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NIH NITAAC Blog

A blog by Sr Acquisition Consultant in General

Are You Curious About Oral Presentations?

• oral presentations
• real time solicitation
• industry proposal

Entry posted by Sr Acquisition Consultant in NIH NITAAC BLOG March 8, 2022

6,177 views

Did you know …

• that many industry proposal writers take on proposal development duties on top of their 40-hour work week?
• that written proposals are sometimes created by updating the last response, bearing the uncaught typos and prior agency names?

Imagine a real time solicitation response tailored to your requirement. With a properly developed solicitation, this could be exactly what you get.  

I’ve yet to see a successful one-size-fits-all approach to contracting. Of course, certain techniques and approaches have worked well over the years—they are our best practices. Even so, sometimes it’s time to try something new because maybe that will work too. Not convinced? What do you think when you read this brief comparison between written responses and oral responses?

  Do I have your interest…but perhaps you’re not sure where to start? If so, why not try an initial practice step that will help build your muscles?   A simple approach is to lead your program and acquisition team through one-on-one market research sessions. What will that do for you? Consider the following:

Perhaps you can see by the roles and actions above that interactive market research trains the government team’s muscles and prepares them for similar activities in oral presentations. By facilitating one-on-one market research sessions, the government not only receives better industry insights, it helps smooth the process for successful oral presentations. These sessions provide industry with an opportunity to help the government with relevant feedback and real time to rehearse oral presentations. Additionally, it benefits all with experience in time management--which is critical for oral presentations.

Are you ready to get started using oral presentations?  

Are you feeling uncertain about walking the oral presentations plank? You are not alone! Many of my program offices were reluctant to try oral presentations. But once they went through the process with me, they’ve all said they only want to use oral presentations going forward. Why? Because the value of oral presentations to the government from industry competitors is immediately evident. It distinguishes a detailed and tailored solution from a check-the-box regurgitation of your solicitation.

In part 1, we discussed some first steps to prepare your team for oral presentations. Now, in part 2 of this series, we’ll finish our discussion of preparation and cover the importance of establishing a clear and coherent solicitation process. This process includes using effective solicitation language, tips to communicate with the competitors and options to conduct oral presentations.

As you know, oral presentations are a show, not tell, practice to find an industry solution to a government solicitation. However, orals don’t run themselves. For smooth sailing, I cannot emphasize enough that the contracting team post a draft solicitation early in the process. This draft should include information about your oral presentation process or at least that you will be using oral presentations. Who benefits from early engagement? Everyone does, here’s how:

At a minimum, early communications can eliminate the government scrambling for answers, making revisions and avoid extending the solicitation’s closing date. This is even more critical during oral presentations because employee schedules have been cleared and conference rooms have been reserved. To avoid rough waters, plan your orals and follow your plan.

To conduct oral presentations, a best practice is having a process plan in place and publishing certain elements of it in the solicitation (see sample at the end of this article). Much of the information here focuses on oral presentations in a virtual environment. Consider the following logistical choices:

Now that we’ve covered the preparation portion of this process, let’s focus on developing clear and coherent solicitation language. I cannot overemphasize how helpful it is to share up front everything industry needs to know to participate in your oral presentations. Such language is always dependent on the requirement however, I’ve included sample language at the end of this article. This language has evolved over time and I anticipate it will continue to evolve.   The intent of sharing it is to help you get started.

It’s up to you to find the right plan that fits your requirement and your team. However, here is one tried and true approach to conducting orals. Consider:

When it comes to due diligence, perhaps you can see by the roles and actions above, oral presentations aren’t much different from written response evaluations. Oral presentations do not remove any responsibilities in our procurement process. Rather orals are a streamlined approach where the acquisition team works together to hear and review the real-time presentation simultaneously.

The information in this part may seem hefty but it will begin to make more sense as you get started and make it your own. You are not alone – consider reaching out to a trusted colleague or join the federal mentoring community at https://openopps.usajobs.gov/communities/13 for further assistance. For now, I invite you cast anchor and walk confidently through orals, complete your evaluations and prepare for debriefings.

Sample solicitation language:

Oral presentations date:

The government will contact contract holders with the actual date, time, virtual location, and other logistical instructions for the oral presentations. Competitors will be managing their own presentation including sharing slides, changing slides, etc. Assigned times will be provided on a first come, first served basis. Please be prepared with your team’s availability and expect contact from the government for this information within approximately an hour after the task order request has closed. The government intends to hold oral presentations the week of (provide an estimate or at a minimum add these dates in the final solicitation).  

Within five business days of issuing this task order request, or when feasible, the government asks for a courtesy notification from the contract holder if their company intends to compete for this work. This courtesy will allow the government to complete the logistics for oral presentations. Contract holders may send this notification to the contracting officer and contract specialist.

Technical Presentation Instructions

Contract holder submissions must be clear, coherent and delivered in enough detail for the government to determine its level of confidence in the contract holder’s ability to perform the requirements of this task order (TO). Presentations must clearly demonstrate how the competitor intends to accomplish the project and must include convincing rationale and substantiation of all claims.

Contract holders must use their own equipment to deliver the presentation. The government conference room may include standard equipment such as a lectern, microphone, presentation screen with computer connection cords, guest Wi-Fi, etc..   Competitors may arrive up to 30 minutes before the scheduled time of their presentation to set up, test connectivity, etc.   The government will provide an electronic invitation to the contract holder with a link to attend the presentation .

Competitors may bring up to nine attendees. Competitors are encouraged to have only proposed personnel deliver the presentation. For the successful contract holder who wins this TO, please note the annual contract holder performance assessment may include a government statement assessing the proposed personnel, what personnel performed, and any disruptions that may delay work due to contract holder personnel replacements.   Any firm may attend only one oral presentation, whether for itself as a prime contract holder or as a subcontractor for only one prime firm.

Contract holders will use the exact presentation submitted at the close of the TO request. The contracting officer will ensure the written presentation is identical to the submitted documents, any substitutions may disqualify a contract holder from award. Contract holders’ presenters and attendees may not use electronics, phones or other means to reach their firm for any input during the presentations.  

Oral presentations may be recorded. Given current global conditions, there is a high probability oral presentations may be, in whole or in part, held virtually. If the presentation is not held virtually, this determination will be decided by mutual agreement between each contract holder and the government. If presentations are held virtually, each member of the competitor’s team may be required to adhere to more specific restrictions. Such restrictions may include signing a statement certifying during the time of the presentation the member did not reach out to resources outside of the identified and present oral presentations team.   The contract holder is responsible for sending the names and email addresses of all oral presentation participants to the contracting officer and contract specialist prior to the start of the presentation.

Due to internal government technological connectivity issues the government prefers to use a WebEx meeting for virtual orals.   The government is open to alternate software solutions however alternate suggestions will require a connectivity check prior to scheduling oral presentations.

Sample solicitation schedule

 Sample email calendar invitation

Team Competitor:

Thank you for your interest in our requirement. We have agreed upon the following date and time for your presented solution to this requirement. We look forward to meeting you online. Please forward this calendar invitation to the appropriate members of your team.

If you have any questions between now and this meeting please let us know. We will open the WebEx session at exactly 7:30 am ET so you may begin any preparation which suits your team.  

If presentations are held virtually, each member of the competitor’s team may be required to adhere to more specific restrictions. Such restrictions may include signing a statement certifying during the time of the presentation the member did not reach out to resources outside of the identified and present oral presentations team.  The contract holder is responsible for sending these signed statements after the presentation (a personal email from each team member is acceptable) to the contracting officer and contract specialist no later than close of business the day the oral presentations are held.

The contract holder is responsible for sending the names and email addresses of all oral presentation participants to the contracting officer and contract specialist prior to the start of the oral presentation.

                (insert a copy of the oral presentations table schedule from your solicitation)

               Thank you,

               Contract specialist  

Oral presentations are over, now what?

Congratulations! You’ve made it through the biggest part of oral presentations—conducting them.

Throughout this series, we’ve covered a lot of information about oral presentations. In part 1 we discussed first steps and preparations, in part 2 we wrapped up preparations and conducted oral presentations. And just when you thought it was safe to go back in the water, I’m telling you there’s more to it. I invite you to stick with me for part 3, where we’ll look at ways to close out oral presentations.   Specifically, we’ll focus on debriefings and capturing lessons learned.

Under our NITAAC GWAC task order solicitations we use FAR 16.5 processes which guide our award notifications and debriefings. Let’s break out a few items for your consideration.

Now let’s focus on capturing lessons learned. For those who are committed to continuous professional development, this is a never-ending process. One approach is to survey, interview and separately ask your technical evaluation panel members, industry competitors and your contracting team. There are a few places in the process where I’ve found asking for feedback to be most helpful. They are: At the end of the last technical evaluation panel consensus meeting (program); during scheduled debriefings (industry) and after the kickoff meeting (your contracting team). Here are a few questions to consider asking:   Did we meet our goal? What worked? What did you like? What might still be unclear? What would make this process better? Would you do oral presentations again? If so, how come?

I find oral presentations an invaluable addition to streamlining my procurements. Thank you for sticking with me for this series. I would love to hear your feedback: How has it helped you? What could be added? What could be improved? Is there anything else you would like to share?

Sample language for debriefing oral presentations

Near the beginning of the debriefing I share something like:

Before we begin, I would like to provide a general overview of the oral presentation process. As noted in the FAR, oral presentations can be effective in streamlining the source selection process.   Our oral presentation structure and schedule as published in the solicitation was identical for all competitors. The overall oral presentation process includes the morning schedule as noted in solicitation. The technical evaluation team received a copy of the slide deck and supporting documents (excluding price) the morning of each presentation. After the oral presentation the government team resumed in the afternoon to conduct the technical evaluation and consensus. The CO facilitated the evaluation and consensus. At the conclusion of the oral presentations for all competitors the government team met again and performed a review of the pricing.

               ---

I conclude oral presentations debriefings with something like:

For oral presentations I provide the following general information to all contract holders whom I debrief

a.       Consider making concluding statements. For instance, a competitor may spend time discussing how an approach was used in another environment. How does that translate to the current requirement? A concluding statement might be: “Based on the experience we just described we excel at ____, from our assessment of your environment, we will use ___ approach. Consequently, in your environment we anticipate this will do ___ and ___. The benefit to the government of this approach is ___.”  

b.       Consider minimizing a focus on historical accolades. If in personal employment interviews it is the time to talk about yourself, in oral presentations it is the time to talk about the government’s requirement. How well do you know the specific government agency and its environment? What is your solution? How would your detailed understanding be applied in the specific government environment?

Who do I contact?

Kelly Lael is an assisted acquisition contracting officer at NITAAC. She is passionate about solving problems in an innovative manner that highlights the strengths and talents of federal employees. Please contact Kelly at 301.402.5683 and [email protected] .

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Top 10 Logistics PPT Templates with Samples and Examples

" Logistics " was originally a  defense term used to represent how military personnel acquired, stored, and transferred equipment and supplies. In today’s business world, however,   the expression is  used to describe how resources are managed and transferred across the supply chain, especially those running  manufacturing units. .

Logistics play a  strategic role in business. Among retailers and wholesalers, they go beyond inventory management and transportation to cover important variables in company success: Location in relation to markets or suppliers. Logistics PPT in manufacturing is concerned with fundamental issues, such as plant location, raw material procurement, and customer service requirements. In recent years, developments in the business landscape have required firms of all sizes to dedicate close consideration to how this function interacts with others.

From Source to Destination: Logistics Simplified

There is no better example to understand the logistics process than that of Amazon or FedEx . These global logistics giants exemplify modern logistics, seamlessly connecting manufacturers, distributors, and consumers worldwide.

Picture this: You are sitting at home and decide to order a book from Amazon. You find the book you want on their website and place your order. With just a few clicks, you've initiated a logistical process that involves multiple parties. First, Amazon's system communicates with the publisher or supplier of the book to confirm availability and initiate the shipment. Once the book is ready to be shipped, it's picked up from the publisher's warehouse by a logistics partner or Amazon's delivery network. The book then goes through a series of steps in the logistics chain, including sorting, packaging, and transportation. Finally, the book arrives at your doorstep, completing the logistical journey.

Through this process, Amazon fulfills its responsibility to ensure timely delivery to its eight billion-strong consumer base, showcasing the pivotal role of logistics in today's interconnected world.

LOGISTICS PPT TEMPLATES

With SlideTeam’s logistic PPT Templates , you can be assured that you will be able to:

• Draft an impressive logistics business proposal
• Track your company activities, inventory and logistics, and revenue through our dashboards .
• Stay informed about the transport of raw materials, goods, and supply chain
• Bridge the gap between clients (sellers and buyers).
• Track Key Performance Indicators (KPIs)

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Let's explore these Top 10 Logistics PPT Templates with Samples and Examples

Template 1: Logistics Business Proposal PowerPoint Template 

Whether you’re considering opening up a small local package delivery business or picturing your future as an international shipping magnate, every logistics business has to start somewhere. The best start to that is by drafting a proposal. This logistics business proposal Template in 22 slides highlights the cover letter, table of contents, project context, business offerings, and more. The logistic process, stakeholder or client investment, certification are part of the package. A summary of the firm is also included in this resourceful bundle.  Download now!

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Template 2: Inventory and Logistics Revenue and Cost Dashboards

The logistics analytics dashboard is like a control center. It collects lots of data and shows you how to manage logistics efficiently. It’s not just about displaying data; it’s about presenting it in a readable, visual format. This is where an inventory and logistics revenue and cost dashboard comes into light, transforming columns of numbers into understandable charts and graphs for more accessible data visualization. Download now!

Template 3: Logistics Company Organization Chart Supply Chain Company Profile

An organizational structure is a strategy that outlines how certain activities are overseen to achieve the goals of an organization. These activities include rules, roles, and responsibilities. The organizational network also specifies how information flows between levels within the company. This PPT  Slide highlights the organizational chart of the supply chain or logistics company. It includes transportation, a warehouse, international forwarding, a shipping agency, and a finance department. Download now!

Template 4: Logistics Automation Systems PowerPoint Template

Logistics Automation Systems PowerPoint Template covers a logistics company’s introduction with its designs, controls, and details on supply chain management. This PPT illustrates logistics company operations during supply procurement, storage, transportation, order fulfillment, and distribution, depending on the commercial agreement between the parties.   This presentation also covers the reasons for poorly integrated shipping and logistics management in the company. It mentions the need for an effective logistics management system.  Using this PPT Template, you can even showcase a  solution to overcome the gap between business and technology. Lastly, this PPT aims to provide details on cost-efficient, streamlined, and error-free solutions through automating the processes and using secured software to carry out  tasks. Download now!

Template 5: Warehousing Logistics PPT Template

Enhance warehouse workforce management with our Warehousing Logistics PowerPoint deck. This inventory setup template comprises  slides discussing  statistics related to effective warehouse management. It includes slides on handling warehouse arrangement, managing warehouse fulfillment strategies, optimizing operations, enhancing workforce management, investment analysis, etc. The primary functions of warehouse logistics are:

• To store products efficiently, ensure they are protected and in the proper conditions for preservation.
• Managing stored product inventories, recording incoming and outgoing products, verifying stock, and generating inventory reports.

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Template 6: Logistics Transport Company Profile PowerPoint

A company profile is a professional overview of a  firm's activities, goods, and services for prospective clients. This PowerPoint Template for Logistics Transport Company Profile includes freight, shipping, and cargo transportation rules, among other things. It features an executive summary, firm overview, awards and accomplishments, subsidiaries, purpose, vision, and core values. Use it to demonstrate international presence and global supply chain channels. It includes transport services, a logistics fleet, a pricing system, and a business plan. This PowerPoint deck includes the management team and organizational structure, company history, ownership structure, client testimonials, the organization's plan, SWOT analysis, CSR efforts, and costs. Download now!

Template 7: Export Logistics PPT Template

Logistics for export refers to the complete supply chain channel, including order handling, shipping, inventory management and handling, storage, packing, and clearance of export items.  This PPT Template, a complete deck in 17 slides, highlights an export logistic management workflow, documentation requirements, strategies to optimize the export logistics process, and more.  Efficient logistics management can lend a competitive edge to any export organization by improving order processing and cash flows. Download now!

Template 8: Supply Chain Management And Logistics PPT Planning Transportation Comparison Importance Businesses

Supply chain logistics manages the storage and delivery of products along the supply chain. The approach starts with raw materials, moves on to manufacture and distribution, and concludes when a company delivers finished products to a consumer or their final destination. At the same time, logistics is concerned with transporting and storing goods within the supply chain. This PowerPoint Template in 12 slides includes essential elements of supply chain and logistics, the benefits of each, and a comparison table of logistics and supply chain management. This template bundle also includes the importance of logistics training in supply chain management. Download now!

Template 9: Transport Management Dashboard For Logistics Company With Fleet Status

Track your delivery and logistics status with this designated dashboard template. This PowerPoint Slide displays the KPI dashboard to measure the company's transportation management efficiency for optimizing its  delivery time. It includes elements like revenue, cost, shipments, profit by country, etc. Download now!

Template 10: One-Pager Transport and Logistics Business Plan

Logistics companies are the actual and figurative wheels of the global economy. The transportation and logistics business is essential to the economy because it transports commodities from source to customer. One of the most critical steps in making your business successful is writing a business plan for logistics. This one-page PowerPoint Slide showcases ways to improve customer satisfaction rates and reduce logistics business distribution and transportation costs. It depicts details related to the company overview, key highlights, vision, industry analysis, marketing plan, etc. of the business. Download now!

Efficiency in Motion

In modern times, technological development and the complexity of logistics procedures have given rise to logistics management programs and specialized logistics-focused organizations that speed up the transfer of resources throughout the supply chain. The logistics function inside a firm comprises elements such as order processing, inventory control, warehousing, material handling, customer service, and demand forecasting. When a firm optimizes its logistics, it increases efficiency across the whole supply chain. Understanding how to get the appropriate resources to the correct location at the right time is e a competitive advantage for a company, bringing value to the customer while lowering costs and increasing profitability.

Related posts:

• Top 5 Inventory Management Templates with Samples and Examples
• [Updated 2023] Top 50 Scorecards and Dashboards PowerPoint Templates to Analyze your Business Performance
• Top 25 Travel, Transportation and Logistics PowerPoint Templates to Keep your Boat Afloat!
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98 Top Logistics Startups & Companies (Moscow)

Avtoplanshet

Service that provides taxi passengers with a free tablet during the ride and advertisers get access to a new audience Based out of Moscow, Moscow City, Russian Federation

Twitter | Facebook | Linkedin ‍

Learn more about their finances on Crunchbase

R Group is a cargo, freight and logistics agency. Based out of Moscow, Moscow City, Russian Federation

United Europe Group

United Europe Group provides distribution, logistics, retail, development, and production services of perfumery and cosmetic products. Based out of Moscow, Moscow City, Russian Federation

Dilex offers a IT-platform for building effective transport logistics by cargo owners and carriers. Based out of Moscow, Moscow City, Russian Federation

Service for automatic online-stores logistics Based out of Moscow, Moscow City, Russian Federation

Beluga Projects Logistic

Beluga Projects Logistic is a logistics & transportation agency offering freight, warehouse logistics, outsourcing & consulting services. Based out of Moscow, Moscow City, Russian Federation

East-West company is a supplier of restaurants and confectionery industries. Based out of Moscow, Moscow City, Russian Federation

M&TM Freight

M&TM Freight offers local and international freight forwarding services. Based out of Moscow, Moscow City, Russian Federation

ZTM Logistic

ZTM Logistics as providing transportation delivery packing industries. Based out of Moscow, Moscow City, Russian Federation

MultiRoad is a digital logistics service company that offers freight forwarding, multimodal container logistics and transportation services. Based out of Moscow, Moscow City, Russian Federation

MUST Insurance

MUST Insurance is an insurance firm which provides logistics based carrier liability, driver accident, and cargo insurance products. Based out of Moscow, Moscow City, Russian Federation

Courier Service Express

Courier Service Express is a logistics company. Based out of Moscow, Moscow City, Russian Federation

FINDOSTAVKA

FINDOSTAVKA is 1st marketplace broker for the delivery of legally significant financial documents in Russia Based out of Moscow, Moscow City, Russian Federation

ROMAX FINE ART

Specialist White Glove Logistics Focused on High Value Furniture, Artwork and Antiques Based out of Moscow, Moscow City, Russian Federation

AAA Cargo offers railway, air, sea transportation and temperature-sensitive freight solutions for pharmaceuticals and clinical trials. Based out of Khimki, Moscow City, Russian Federation

Providing cloud fulfillment automation for small and mid-sized ecommerce companies. Based out of Moscow, Moscow City, Russian Federation

B2CPL is a logistics firm that provides cash service, courier delivery, packaging, and other services to e-commerce companies. Based out of Moscow, Moscow City, Russian Federation

Vig Trans offers international logistics, customs clearance, and legal support for foreign trade activities services. Based out of Moscow, Moscow City, Russian Federation

Transsertico

Transsertico is a freight company that offers customs clearance, cargo, logistics, certification, and foreign trade outsourcing services. Based out of Moscow, Moscow City, Russian Federation

UTLC ERA specializes in cargo transportation and logistics services. Based out of Moscow, Moscow City, Russian Federation

Fastdo offers an express delivery service in moscow that takes 90 minutes. Based out of Moscow, Moscow City, Russian Federation

CityVans provides transportation services for the packaging, labeling, and delivery of goods. Based out of Moscow, Moscow City, Russian Federation

Svetlana-K provides transportation, logistics, project management, and consulting services. Based out of Moscow, Moscow City, Russian Federation

Antares Trading

Antares Trading specializes in freight, warehouse, import, export, and trade services as well as provides transport and logistics solutions. Based out of Moscow, Moscow City, Russian Federation

Gruzhunter is a logistics company that provides local and regional transportation through cargo services. Based out of Moscow, Moscow City, Russian Federation

Gulliver & Co International

Gulliver & Co International is a management consulting firm that offers logistics, legal, IT, financial, and personnel management services. Based out of Moscow, Moscow City, Russian Federation

Rail Garant

Rail Garant offers transportation of goods, liquid cargo, cars, and construction materials through railways of the Russian Federation. Based out of Moscow, Moscow City, Russian Federation

Deliverator

SaaS for managing mobile workforce Based out of Moscow, Moscow City, Russian Federation

Garpix provides cargo space planning system inorder to distribute cargo in a container, truck on a pallet in 3D mode. Based out of Moscow, Moscow City, Russian Federation

LCM Express

LCM Express offers transportation, logistics, and courier service. Based out of Moscow, Moscow City, Russian Federation

ArmPack is a decentralized eco-system designed for protection against forgery. Based out of Moscow, Moscow City, Russian Federation

Major provides logistics, transportation, shipping, terminal handling, and cargo insurance services. Based out of Moscow, Moscow City, Russian Federation

Freight One

Freight One is a provider of cargo transportation services. Based out of Moscow, Moscow City, Russian Federation

STA Logistic

STA Logistic is a logistic and supply chain company. Based out of Moscow, Moscow City, Russian Federation

RFID Engineering

RFID Engineering develops and markets RFID solutions for various industries such as warehouse, production, logistics, and inventory control. Based out of Moscow, Moscow City, Russian Federation

KPD-Cargo is a logistics services provider based in Moscow. Based out of Moscow, Moscow City, Russian Federation

S2B Group is a web services providing firm that offers software services for automation of transport logistics and freight management. Based out of Moscow, Moscow City, Russian Federation

Traft is a logistics and cargo transportation firm that provides warehousing, audit services in transportation, and software solutions. Based out of Moscow, Moscow City, Russian Federation

Free Lines is a transportation and logistics company that imports clothes and furniture to various international destinations. Based out of Moscow, Moscow City, Russian Federation

BIOCARD is a pharmaceutical and logistics company. Based out of Moscow, Moscow City, Russian Federation

Sendie is a platform which offers people to ship goods, parcels and deliver them in flexible and affordable prices. Based out of Moscow, Moscow City, Russian Federation

Take'N'Go

Take'N'Go is a courier service company. Based out of Moscow, Moscow City, Russian Federation

dropnship.ru

Dropshipping online platform for suppliers. They receive a new sales channel, online stores and don't carry warehouse and logistics costs. Based out of Moscow, Moscow City, Russian Federation

Logistic tools

Logistics Tools provides a route planning & vehicle management software for the logistics industry. Based out of Moscow, Moscow City, Russian Federation

NAWINIA is a logistics and supply chain management company. Based out of Moscow, Moscow City, Russian Federation

Transport Development

Transport Development is a cargo, and freight service company. Based out of Moscow, Moscow City, Russian Federation

First Open-Community Logistics Platform Based out of Moscow, Moscow City, Russian Federation

WelShip LLC

WelShip.com is a free service that helps you find a carrier for your shipment. Based out of Moscow, Moscow City, Russian Federation

RTL is a provider of logistics and freight services. Based out of Moscow, Moscow City, Russian Federation

Extremely safe electric air vehicle (VTOL) Based out of Moscow, Moscow City, Russian Federation

Global Logistic Projects

Global Logistic Projects provides warehouse logistics and customs clearance services. Based out of Khimki, Moscow City, Russian Federation

Filuet provides professional contract logistics and BPO solutions to help foreign companies expand into the emerging markets. Based out of Moscow, Moscow City, Russian Federation

Russian Logistic Service

Russian Logistic Service provides full range of logistics services transportation, warehousing, custom clearance, certification, consulting. Based out of Moscow, Moscow City, Russian Federation

STS Logistics

STS Logistics provides warehouse logistics, forwarding and outsourcing services. Based out of Moscow, Moscow City, Russian Federation

Irbis is a supplier of Rescue equipment and machinery. Based out of Moscow, Moscow City, Russian Federation

Sovtransavto

Sovtransavto offers logistic and transport services, warehousing, insurance, cargo processing, and affiliated legal solutions. Based out of Moscow, Moscow City, Russian Federation

TENEX supplies nuclear fuel cycle and uranium products along with compliance and logistics services. Based out of Moscow, Moscow City, Russian Federation

UAV, drones, turbogenerators Based out of Moscow, Moscow City, Russian Federation

Mosgortrans

Mosgortrans is a transportation service provider company operating bus and electrical bus networks in Moscow. Based out of Moscow, Moscow City, Russian Federation

JSC Belomortrans

JSC Belomortrans offers trucking, air, sea, river and rail transportation, and warehousing services. Based out of Khimki, Moscow City, Russian Federation

CUBQ Transport and Logistics

CUBQ Transport and Logistics offer project transportation, bulky transportation and general cargo transportation services. Based out of Moscow, Moscow City, Russian Federation

Orfe is a 4 PL provider that offers comprehensive pharmaceutical and para-pharmaceutical logistics and warehouse services. Based out of Moscow, Moscow City, Russian Federation

Nipigas offers project management, equipment procurement, logistics, construction management, pre-commissioning, and documentation services. Based out of Moscow, Moscow City, Russian Federation

Pola Tech is a maritime company specializing in SaaS-based subscription solutions for voyage, deals, and fleet management Based out of Moscow, Moscow City, Russian Federation

INIER operates in the field of freight transportation to services on organization of transportation by air, road, rail, river. Based out of Moscow, Moscow City, Russian Federation

VVP Group deals with the distribution, logistics and warehousing of mobile phones, tablets, modems and related accessories. Based out of Khimki, Moscow City, Russian Federation

AI Eye is a driver monitoring app that automatically detects distracted driving and fatigue Based out of Moscow, Moscow City, Russian Federation

GetMeNow is a same-day delivery platform that enables its users to get products delivered in less than 90 minutes. Based out of Moscow, Moscow City, Russian Federation

Aviazapchast JSC

Aviazapchast is a foreign trade company specializing in the supply and after-sales service of domestic civilian & dual-use aircraft abroad. Based out of Moscow, Moscow City, Russian Federation

Volga-Dnepr Group

Volga-Dnepr Group is an air cargo company that provides transporters and scheduled cargo operations services. Based out of Moscow, Moscow City, Russian Federation

Pingdelivery

Collaborative Last-mile Delivery Platform. Get last-mile delivery seamlessly integrated with your business. Based out of Moscow, Moscow City, Russian Federation

SPSR-Express

Offers a broad range of services in relation to express delivery of documents, mail and cargo all over Russia and abroad Based out of Moscow, Moscow City, Russian Federation

The market-leading private Courier, Express and Parcel (CEP) operator in Russia Based out of Moscow, Moscow City, Russian Federation

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• Global Spine J
• v.9(2 Suppl); 2019 May

Oral Presentations

Op01: degenerative-cervical 1, a001: pain is the recovery priority for patients with degenerative cervical myelopathy, benjamin davies 1 , oliver mowforth 1 , iwan sadler 2 , bizhan aarabi 3 , brian kwon 4 , shekar kurpad 5 , james harrop 6 , jefferson wilson 7 , robert grossman 8 , and michael fehlings 7, 1 university of cambridge, cambridge, uk, 2 myelopathy.org, 3 university of maryland, college park, md, usa, 4 university of british columbia, vancouver, british columbia, canada, 5 medical college of wisconsin, milwaukee, wi, usa, 6 thomas jefferson university hospital, philadelphia, pa, usa, 7 university of toronto, toronto, ontario, canada, 8 houston methodist hospital, houston, tx, usa.

Introduction: Degenerative cervical myelopathy (DCM) is a very common and disabling condition caused by chronic compression of the cervical spinal cord from surrounding degenerative changes of the spine. At present the only treatment available is surgical decompression. While this is able to stop disease progression, recovery after surgery often remains incomplete and many patients are left with life-long disability. Individuals with DCM suffer among the lowest quality of life scores of all chronic diseases, yet their suffering is poorly understood. The present study therefore aimed at establishing relevant functional domains and recovery priorities for DCM sufferers. Material and Methods: Functional domains were established as part of qualitative interviews and a consensus process. A cross-sectional survey was advertised via a DCM charity (Myelopathy.org) and Google AdWords. Individuals were asked about their disease characteristics, including limb pain (visual analogue scale) and functional disability (patient-derived modified Japanese Orthopaedic Association score). They were also asked to rank the established recovery domains (arm and hand function, walking, upper body/trunk function, sexual function, elimination of pain, sensation and bladder/bowel function) in order of priority. Priorities were analyzed as the modal first priority and mean ranking. The influence of demographics on selection was analyzed, with significance P < .05. Results: Of 659 survey responses obtained, 481 were complete. Overall, pain was the most popular recovery priority (39.9%) of respondents, followed by walking (20.2%), sensation (11.9%), and arm and hand function (11.5%). Sexual function (5.7%), bladder and bowel (3.7%), or trunk function (3.5%) were chosen less frequently. When considering the average ranking of symptoms, while pain remained the priority (2.6 ± 2.0), this was closely followed by walking (2.9 ± 1.7) and arm/hand function (3.0 ± 1.4). Sensation ranked much lower (4.3 ± 2.1). With respect to disease characteristics, overall pain remained the recovery priority, with the exception of patients with greater walking impairment ( P < .005) who prioritized walking, even among patients with lower pain scores. Conclusion: This is the first study investigating patient priorities in DCM. The patient priorities reported provide an important framework for future research and will help ensure that it is aligned with patient needs.

A002: Surgical Outcome of Anterior Versus Posterior Approach in the Treatment of Cervical Spondylotic Myelopathy: A Propensity-Score-Matched Analysis

Hui yu koh 1 , kenneth cheung 1 , and kenny kwan 1, 1 the university of hong kong, hong kong.

Introduction: Surgical decompression is the only known effective intervention to relieve cervical spondylotic myelopathy (CSM) patients of their symptoms and can be broadly divided into the anterior and posterior approaches. Several studies have compared these 2 approaches. However, no definitive conclusion has been drawn due to methodological bias and inappropriate comparisons. The aim of this study was to compare the surgical outcome in CSM patients undergoing anterior versus posterior approach using a propensity score-matched analysis. Material and Methods: A retrospective cohort study was performed, and medical records were reviewed. Inclusion criteria were patients with a clinical and appropriate radiological diagnosis of CSM with no prior surgical intervention who underwent surgical decompression in our institution between January 2005 and December 2015, aged above 18 years, and a minimum follow-up of 2 years. Exclusion criteria were loss to follow-up, revision surgery, and incomplete clinical data set in the medical records. A 1:2 propensity score matching of the anterior and posterior group was performed. Matching criteria were age at surgery, number of spinal levels involved, preoperative mJOA (modified Japanese Orthopaedic Association) score, preoperative Nurick score, C2-7 SVA (sagittal vertical axis), and C2-7 lordosis. A nearest-neighbor method within 0.02 standard deviations of the calculated score without replacement was performed to adjust for the patients’ baseline characteristics. All statistical analyses were performed using SPSS Statistics software version 24.0 (IBM). A significance level of <.05 was assumed to be statistically significant. Results: A total of 242 patients matched the inclusion criteria and underwent surgical intervention at our institution. Eighty-seven patients were excluded due to incomplete records. The study group thus comprised of 155 patients (43 anterior and 112 posterior surgery patients). A total of 82 patients were matched, consisting of 32 anterior and 50 posterior surgery patients. There was no significant difference in for all covariates after propensity score matching. Overall, both anterior and posterior surgical approach groups did not differ in postoperative Nurick scores, mJOA scores, length of hospital stay, blood loss, and complication rates. Patients who underwent anterior surgery had better maintenance of C2-7 lordosis compared with the posterior group (−8.37 ± 12.1° vs −1.87 ± 13.4°, P < .05). In addition, recovery rate (62.1 ± 26.9% and 49.8 ± 32.3%, respectively) was higher in the anterior group as compared to the posterior group, but this was not found to be statistically significant. Further subgroup analysis based on the cervical sagittal alignments showed that patients with C2-7 SVA and C2-7 lordosis misalignment had better surgical outcomes in terms of postoperative mJOA score (14.7 ± 1.66 vs 13.2 ± 1.92, P < .05) and 1.35 times reduction in relative risk of reoperation ( P = .031) if they underwent anterior surgery compared with posterior surgery. Conclusion: Our findings show that there was no difference in terms of neurologic outcomes between anterior and posterior approaches, which is in line with some of the findings of the recent meta-analyses. However, we found that patients who had undergone anterior surgery had better maintenance of their cervical sagittal alignment. Moreover, patients who had preoperative sagittal malalignment had better clinical outcomes and reduced reoperation rates if they underwent anterior surgery.

A003: Treatment of Cervical Spinal Canal Stenosis With Myelopathy With Corpectomy and Expandable Cage Implantation: 5 Years Outcomes

Vadim byvaltsev 1 , andrei kalinin 1 , marat aliev 1 , evgenii belykh 1 , ivan stepanov 1 , bakhyt aglakov 1 , and bobur yussupov 1, 1 irkutsk state medical university, irkutsk, russian federation.

Introduction: Cervical myelopathy is one of the severe pathological conditions leading to a significant deterioration in the quality of life, a decrease in the ability to work, and disability of patients. The development of clinical symptoms of cervical myelopathy is based on congenital or acquired narrowing of the vertebral canal. To date, an optimal method for treating the stenosis of the cervical spinal canal is the anterior decompression of the spinal cord with interbody fusion by various materials. According to the published data, in a number of cases complications are associated with nontransplantation, repeated compression of neural structures due to migration, difficulty in preparing the required implant size for the restoration of cervical lordosis with prolonged decompression of the spinal cord. The purpose of our study was to analyze treatment results of patients with the degenerative cervical spinal canal stenosis with myelopathy after corpectomy and telescopic expandable cage implantation. Materials and Methods: Authors reviewed 60 patients (35 males, 25 females), mean age 47.3 years (range: 39-62 years), that were available at 5-year follow-up after surgery. Neck Disability Index (NDI), Visual Analogue Scale (VAS), Macnab and Nurick scales were used to assess the preoperative status and clinical outcomes. X-rays and MSCT (multislice computed tomography) scans were used to assess the fusion. Results: All patients had failed conservative treatment within the mean period of 10 months (6-18 months) and proceeded with surgery. One-level corpectomy was performed in 29 (48.3%) patients, 2 levels in 22 (36.7%), and 3 levels in 9 (15%). Significant decrease of pain was revealed after surgery in cervical spine and in upper extremities (mean VAS decreased from 54 to 14, P = .02; and from 62 to 10, P = .015 consequently). Mean NDI decreased significantly at 1-year follow-up from 68 to 16, P = .03, and did not change at the 5-year follow-up. According to the Nurick scale 5 years after surgery full regress of symptoms was achieved in 24 (40%), 29 (48.3%) patients improved, 6 (10%) unchanged, and 1 patient get worse (1.7%). Macnab results were excellent in 19 (31.6%), good in 30 (50%), fair in 10 (16.7%), poor in 1 (1.7%) cases. Fusion was achieved at 1-year follow-up in 48 (80%) cases, at 2 years in 53 (88.3%), at 3 years in 56 (93%), at 4 years in 57 (95%), at 5 years in 58 (97%) patients. MRI (magnetic resonance imaging) showed complete regression of cord lesion in 14 (23.3%) and partial regression in 32 (53.3%) cases. Electromyography showed improvement of F-wave and M-response in upper extremities in 41 (68.3%) patients. There were no complications associated with corpectomy or implant itself but 3 postoperative wound infections and 2 hematomas which were successfully treated conservatively. Conclusion: This retrospective review showed effectiveness of anterior decompression and expandable cages implantation in the patients with degenerative cervical spinal canal stenosis and myelopathy. The robust fixation allowed achieving fusion in the 97% of patients after single and multilevel corpectomies at 5-year follow-up without significant postoperative complications.

A004: Do Cervical Spine Patients Recall Their Preoperative Status? A Cohort Study of Recall Bias in Patient-Reported Outcomes

Ilyas aleem 1 , bradford currier 2 , heidi poppendeck 2 , paul huddleston 2 , jason eck 3 , john rhee 4 , mohamad bydon 2 , brett freedman 2 , and ahmad nassr 2, 1 university of michigan, ann arbor, mi, usa, 2 mayo clinic, rochester, mn, usa, 3 center for sports medicine and orthopaedics, chattanooga, tn, usa, 4 emory spine center, emory university, atlanta, ga, usa.

Introduction: Recall bias is a well-known source of systematic error in clinical research. The accuracy of patient recall following cervical spine surgery, however, remains unknown. We sought to characterize the accuracy of patient recollection of preoperative symptoms after cervical spine surgery. Material and Methods: Consecutive patients undergoing cervical spine surgery for myelopathy or radiculopathy were enrolled. Neck and arm numeric pain scores and Neck Disability Indices were recorded preoperatively. Patients were asked to recall their preoperative status at both short (<1 year) and long-term (≥1 year) follow-up. Actual and recalled scores were compared using paired t -tests and relations were quantified using Pearson correlation coefficients. Multivariable linear regression was used to identify factors impacting recollection. Results: Seventy-three patients with a mean age of 58.2 years were included. Compared to their preoperative scores, patients showed significant improvement in neck pain (mean difference [MD] = −2.9, 95% CI = −3.5 to −2.3), arm pain (MD = −3.4, 95% CI = −4.0 to −2.8), and disability (MD = −12.4%, 95% CI = −16.9 to −7.9). Patient recollection of preoperative status was significantly more severe than actual for neck pain (MD = +1.5, 95% CI = 0.8 to 2.2), arm pain (MD = +2.3, 95% CI = 1.6 to 3.0), and disability (MD = +5.8%, 95% CI = 2.4 to 9.2). Moderate correlation between actual and recalled scores with regard to neck ( r = 0.41), arm ( r = 0.50) pain, and disability ( r = 0.67) was seen. This was maintained across age, gender, and time between date of surgery and recollection. Over 30% of patients switched their predominant symptom on recall. Conclusion: Relying on patient recollection does not provide an accurate measure of preoperative status following cervical spine surgery. Prospective and not retrospective collection of patient-reported outcomes remains the gold standard to measure and interpret outcomes following cervical spine surgery. Recall bias has the potential to affect patient satisfaction and requires further study.

A005: Minimum Clinically Important Difference and Patient Acceptable Symptom State of Japanese Orthopaedic Association Score in Degenerative Cervical Myelopathy Patients

So kato 1 , yasushi oshima 1 , yoshitaka matsubayashi 1 , yuki taniguchi 1 , sakae tanaka 1 , katsushi takeshita 2, 1 university of tokyo, tokyo, japan, 2 jichi medical university, shimotsuke, japan.

Introduction: Despite the worldwide popularity of modified Japanese Orthopaedic Association score (mJOA), the original Japanese Orthopaedic Association (JOA) score is still commonly used in East Asian countries, including Japan. However, unlike mJOA score, the psychometric properties of JOA score remain poorly understood. The objective of the present study was to elucidate the psychometric properties of the original JOA score, including the minimum detectable change (MDC), minimum clinically important difference (MCID), and patient accepted symptom state (PASS). Material and Methods: We retrospectively reviewed a consecutive series of laminoplasty for degenerative cervical myelopathy patients in a single academic institution. Pre- and postoperative JOA scores were collected, and the recovery rate was calculated. The patients were also asked to answer an anchor question analyzing their postoperative health transition used for the MDC and another question assessing the patient satisfaction used for the MCID and PASS. Anchor-based methods were used to determine the cutoff values by a receiver operating characteristic (ROC) curve analysis. Results: A total of 101 patients were included in the analysis. The mean preoperative JOA score was 10.3 (standard deviation [SD]: 2.4), and the mean postoperative JOA score was 13.4 (SD: 2.5). The mean recovery rate was 44%. A total of 68% of the patients admitted that their health condition was at least “somewhat better” than their preoperative condition, and 66% were at least “somewhat satisfied” with the treatment results. Based on ROC curve analyses, the MDC and MCID for JOA score in degenerative cervical myelopathy patients were calculated to be 2.5. The PASS was estimated to be 14.5, and the MCID for JOA recovery rate was 52.8%. Conclusion: The MDC, MCID, and PASS for JOA score for degenerative cervical myelopathy patients were reported by anchor-based ROC curve analyses.

A006: Epidemiology and Outcomes of Neck Pain Following Surgery for Cervical Radiculopathy

Mark a. maclean 1 , ayoub dakson 1 , fred xavier 1 , sean d. christie 1 , and csorn investigators 2, 1 dalhousie university, halifax, nova scotia, canada, 2 canadian spine outcomes research network, toronto, ontario, canada.

Introduction: Degenerative cervical radiculopathy (DCR) is commonly associated with severe neck pain, in addition to arm pain and moderate levels of disability. Many studies have demonstrated improved arm pain following surgery; however, axial neck pain is generally not felt to improve. The purpose of this study was to determine whether surgery for cervical radiculopathy improves axial neck pain. Materials and Methods: This retrospective study utilized data from the Canadian Spine Outcomes and Research Network (CSORN) registry for patients who received surgery for degenerative cervical radiculopathy. Subgroups were comprised of patients that underwent 1-level, 2-level, 3-level ADCF (anterior cervical discectomy and fusion) or cervical disc arthroplasty (CDA). The primary outcome was 12-month postoperative reduction in Visual Analogue Scale for Neck Pain (VAS-NP). Secondary outcomes included Neck Disability Index (NDI), Visual Analogue Scale for Arm Pain (VAS-AP), Short-Form Physical Health Composite Scale (SF-36-PCS), and Mental Health Composite Scale (SF-36-MCS). Results: We identified 79 patients with cervical radiculopathy: 1-level ACDF (38%), 2-level ACDF (35%), 3-level ACDF (8%), and CDA (19%). Preoperative clinical outcome scores were similar for all patients, regardless of procedure. Mean VAS-NP and VAS-AP improved by 3.6 ± 2.7 and 4.4 ± 3.2 points, respectively. Mean change in VAS-NP, VAS-AP, SF-36-MCS, SF-36-PCS, and NDI were not statistically different across surgical groups (for all outcome measures, P > .05). Although VAS-AP was significantly reduced in all surgical groups ( P < .05), only patients undergoing 2-level ACDF and CDA demonstrated significant improvement in VAS-N ( P < .001). Mean change in VAS-NP was not significant for 1-level ( P = .098) and 3-level ACDF ( P = .132) groups, respectively. Conclusion: Reduction in VAS-NP score was similar for all procedures. However, only patients that underwent a 2-level ACDF or CDA demonstrated a statistically significant 12-month postoperative improvement in VAS-NP. This study provides new information on the improvement in neck pain following surgery for cervical radiculopathy and may allow surgeons to more accurately prognosticate patient’s convalescence and aid surgical decision making.

OP02: Trauma-Cervical 1

A007: the clinical implications of adding computed tomography angiography in the evaluation of cervical spine fractures: a propensity-matched analysis, daniel tobert 1 , hai le 2 , justin blucher 2 , mitchel harris 2 , and andrew schoenfeld 2, 1 university of utah, salt lake city, ut, usa, 2 harvard university, boston, ma, usa.

Introduction: Screening asymptomatic blunt trauma patients for cervical arterial injury is controversial. Vertebral artery injury (VAI) is most commonly associated with cervical spine fracture and many guidelines advocate indiscriminate screening of all cervical spine fractures. The purpose of this study is to determine whether the addition of computed tomography angiography (CT-A) results in a change in management for patients with cervical spine fractures. Materials and Methods: Adult patients with acute cervical spine fractures after blunt trauma between 2000 and 2015 were retrospectively identified. Patients with penetrating trauma, neoplasm, or prior cervical spine surgery were excluded. The following variables were recorded: age, biologic sex, medical comorbidities, Injury Severity Score (ISS), mechanism of injury, whether CT-A of the neck was obtained in addition to CT, cervical spine fracture characteristics, and the presence of VAI. Recommendation for a change in management with antithrombosis was the primary outcome measure. Detection of stroke and VAI were secondary outcomes. Propensity score matching was performed to negate the significant baseline demographic and clinical characteristics. Results: There were 3943 patients screened and 2831 patients eligible. Propensity score matching yielded one cohort receiving CT-A and one cohort that did not, both with 644 patients and equivalent demographic and clinical characteristics. CT-A identified definite or indeterminate VAI in 113 patients and 62 patients had antithrombosis recommended. In the cohort without CT-A, VAI was discovered in 11 patients incidentally through other imaging and 8 were recommended antithrombosis. Two patients in the CT-A group had major adverse bleeding events as a result of antithrombosis initiation. There were no preventable strokes in either group. Conclusion: The addition of CT-A increased detection of VAI and antithrombosis recommendation. There was a high incidence of indeterminate CT-A findings. There were no preventable strokes in either cohort and 2 major adverse bleeding events as a result of recommended pharmacologic antithrombosis. Nonselective screening is not warranted and should be limited to a high-risk subset of patients.

A008: The Window of Opportunity for Surgical Decompression in Patients With Acute Traumatic Cervical Spinal Cord Injury

Marko jug 1 , nataša kejžar 2 , matej cimerman 1 , fajko bajrovic 1, 1 university medical center ljubljana, ljubljana, slovenia, 2 university of medicine, ljubljana, slovenia.

Introduction: Acute traumatic spinal cord injury (tSCI) is a devastating event. Recent clinical practice guidelines suggest early surgical decompression (SD), that is, within 24 hours after injury, but the optimal time for SD remains unknown. In this study we aimed to analyze the effect of timing of SD within the first 24 hours after injury and to find the optimal time window for SD in patients with acute cervical tSCI and persistent spinal cord compression in order to achieve a significant neurologic recovery of at least 2 AIS grades. Additionally, we evaluated the association of timing of SD adjusted for the degree of spinal canal compromise (SCC) and severity of SCI (complete or incomplete). Material and Methods: A prospective cohort study of consecutive patients with AIS grades of A through C and fracture and/or dislocation of the subaxial cervical spine with MRI-confirmed spinal cord compression operated on within the first 24 hours after injury was performed. The primary outcome was the change in AIS grade at the 6-month follow-up. Receiver operating characteristic (ROC) curve was used to determine the best cut-point for the time form injury to SD in which the chances for significant neurologic recovery are the highest (Youden index). Multivariate logistic regression was used to model significant neurologic recovery with time to SD, percentage of SCC and injury severity. Results: Of the 73 enrolled patients, 64 patients concluded the study. Forty-one patients presented as (ASIA Impairment Scale) AIS A, 9 as AIS B, and 14 as AIS C injuries. The median time to decompression was 7 hours. Twenty-five percent of patients improved by at least 2 AIS grades, 28% by 1 AIS grade, and 45% experienced no improvement, with 1 patient deteriorating by 1 AIS grade. Time of SD and SCC were statistically significant predictors of neurologic recovery of at least 2 AIS grades, that is, increasing the delay in time from injury to SD or increasing the degree of SCC before SD lowered the chances for significant neurologic improvement. The injury severity was a marginally significant predictor of neurologic recovery with strong correlation to SCC. The optimal time window for SD to achieve a neurologic improvement of at least 2 AIS grades for our population of patients was within 4 hours form injury (95% CI = 4, 9). Sensitivity and specificity at optimal cutoff point were 0.58 and 0.92, respectively. Conclusion: Our results show that the effect of SD on neurologic recovery within the first 24 hours after acute cervical tSCI is time dependent and the optimal time window for SD in our cohort is between the time of injury and the first 4 to 9 hours after injury, depending on the degree of SCC and injury severity. Therefore, due to heterogeneity of tSCI no uniform cutoff for the timing of SD can be set for all patients. Nevertheless, SD should be achieved as soon as possible.

A009: Blunt Cerebrovascular Injury: Incidence and Long-Term Follow-up

Dennis hundersmarck 1 , willem-bart slooff 1 , jelle homans 1 , quirine van der vliet 1 , nizar moayeri 1 , falco hietbrink 1 , gert de borst 1 , cumhur Öner 1 , sander muijs 1 , and luke leenen 1, 1 university medical center utrecht, utrecht, netherlands.

Introduction: Blunt cerebrovascular injuries (BCVI) are identified in 1% to 2% of all blunt trauma patients and can cause ischemic stroke. Computed tomography angiography (CTA) scanning is the diagnostic modality of choice in BCVI suspected patients. Although CTA-scanning capabilities are ever improving, digital subtraction angiography remains the golden standard. Furthermore, data about long-term functional outcomes after BCVI is limited. The aim of this study was to determine BCVI incidence in relation to imaging modality improvements and determine long-term functional outcomes. Material and Methods: This retrospective cohort study was performed at the University Medical Center Utrecht, a Dutch level 1 trauma center. During a 10-year period, from January 2007 till December 2016, all consecutive BCVI patients ≥18 years old were identified. BCVI incidence among the overall blunt trauma group and specific trauma population subgroups (polytrauma, basilar skull fracture, and cervical trauma) was calculated before and after improvements in CTA scanning and contrast administration protocol. Three periods were identified where CTA diagnostic modalities were improved. In the first period (I), from 2007 up to and including 2009, trauma patients received a full body CT angiogram using a 64-slice CT scanner. In the second period (II), during the course of 2010 up to and including 2013, trauma patients received a full body CT angiogram using a 256-slice CT scanner. In the third period (III), during the course of 2014 up to and including 2016, trauma patients received a full body CT angiogram using the same CT scanner used in period II. However, split bolus intravenous contrast administration flow during the second phase of administration was increased from 3 mL/s to 6 mL/s, providing a higher contrast density. In addition, trauma patients presenting in period III with isolated maxillofacial, cervical, or head injuries, visible at CT scanning, received additional CTA scanning. Long-term functional outcomes following BCVI, using the EuroQol 6-dimensional (EQ-6D) telephonic questionnaire, were determined. Functional outcomes were compared to reference populations, using the EQ-5D index score. Results: Seventy-one BCVI patients were identified among approximately 12 000 (0.59%) blunt trauma patients. In the first period (I) BCVI incidence among the overall blunt trauma group and polytrauma, basilar skull fracture, and cervical trauma subgroups was found to be 0.3%, 0.9%, 1.2%, 4.6%, respectively, which more than doubled toward the third period (III), resulting in 0.8%, 2.4%, 1.9%, 8.5%, respectively. Ischemic stroke as a result of BCVI was found in 20 patients (28%). Six in-hospital deaths were BCVI related (8%). Functional outcomes were determined by the EQ-5D score, with a follow-up rate of 83%. BCVI patients reported lower functional outcomes compared with the Dutch reference population of the same age ( P < .001), as well as the general trauma population presenting at the same institution ( P < .01). Ischemic stroke was identified as a major cause of functional impairment at long-term follow-up. Conclusion: Improved CTA diagnostic modalities have increased BCVI incidence. Furthermore, BCVI patients reported significant functional impairment at long-term follow-up.

A010: Unbiased Recursive Partitioning to Stratify Patients With Acute Traumatic Spinal Cord Injuries: External Validity in an Observational Cohort Study

Nathan evaniew 1 , nader fallah 1 , carly rivers 1 , vanessa noonan 1 , tova plashkes 1 , zeina waheed 1 , brian kwon 1 , charles fisher 1 , and marcel dvorak 1, 1 university of british columbia, vancouver, british columbia, canada.

Introduction: Clinical trials of novel therapies for acute traumatic spinal cord injuries (SCI) are extremely challenging because variability in spontaneous neurologic recovery can make discerning actual treatment effects challenging. Unbiased Recursive Partitioning regression with Conditional Inference Trees (URP-CTREE) is a novel approach to this challenge that was developed through analyses of a large European SCI database (EMSCI). URP-CTREE uses early neurologic impairment to predict how much motor recovery individual patients will achieve, and it holds potential to optimize clinical trial design by efficiently stratifying patients and decreasing required sample sizes. We performed an external validation study to determine how well a previously reported URP-CTREE model stratified patients into distinct homogeneous subgroups and predicted subsequent neurologic recovery when applied to an independent cohort. Methods: We included all eligible patients from an ongoing prospective cohort study that presented to a single academic quaternary care referral center from May 2004 to February 2018 with complete American Spinal Injury Association (ASIA) Impairment Scale (AIS) A acute traumatic cervical spinal cord injuries and baseline motor levels at C4 to C6. We applied the previously reported URP-CTREE model and evaluated Upper Extremity Motor Score (UEMS) recovery at final follow-up. We tested univariate associations with the Pearson correlation coefficient, and differences between medians with the Mann-Whitney U test. We considered recovery to be correctly predicted when final UEMS scores were within a prespecified threshold of 9 points from the median in each group. Results: We included 101 cervical AIS A patients, whose mean times from injury to baseline and follow-up neurological examinations were 6.1 days (SD 17) and 235 days (SD 71), respectively. Median UEMS recovery was 7 points (interquartile range [IQR] = 2 to 12). We applied the previously reported URP-CTREE model, which partitioned our cohort into 5 stratified groups of predicted UEMS recovery, according to 4 predictor variables. One of the predictor variables was not statistically significant in our independent sample of patients, one of the stratified groups did not fit a consistent sequence of progressively improving UEMS scores, and 3 of the 5 stratified groups had medians that were not significantly different from their adjacent groups. However, the model correctly predicted UEMS recovery in 86 patients (85%). Prediction accuracy decreased to 75% in a sensitivity analysis that included only those patients whose time from injury to baseline neurological examination was less than 24 hours (n = 63). Conclusions: A previously reported URP-CTREE model had limited ability to stratify patients into distinct homogeneous subgroups, but reasonably promising accuracy for predicting final motor recovery in an independent cohort of acute cervical AIS A patients. Our cohort had earlier baseline examinations than the majority of patients in the EMSCI database, but their examinations were still later than that which is typical for enrolment in acute clinical trials. Further research is warranted to evaluate the external validity of URP-CTREE among patients with incomplete injuries and to investigate additional strategies for accurately stratifying patients with acute SCI.

A011: Early Complications, Morbidity, and Mortality in Octo- and Nonagenarians Undergoing Posterior Intraoperative Spinal Navigation Based C1/2 Fusion for Acute Traumatic Odontoid Type II Fractures

Basem ishak 1 , till schneider 1 , valerie gimmy 1 , andreas unterberg 1 , and karl kiening 1, 1 heidelberg university hospital, heidelberg, germany.

Introduction: Odontoid type II fractures are the most common cervical spine injury in the elderly. Recent studies confirm that external stabilization is associated with high mortality and complication rates. The decision for surgical treatment is still controversial, particularly with regard to elevated perioperative risk owed to frequent comorbidities and poor bone quality. Modern navigation may help improve perioperative safety and efficacy and thereby reduce complication rate. The aim of this study was to assess short-term mortality as well as mid-term clinical and radiological outcome in elderly. Material and Methods: Thirty-five patients with an acute traumatic odontoid type II fracture who underwent posterior atlanto-axial instrumentation with a modified Goel-Harms technique at our institution between January 2007 and December 2015 were retrospectively analyzed and prospectively examined clinically and radiologically. Comorbidities were stratified using the age-adjusted Charlson Comorbidity Index (AACCI). Mortality, length of ICU (intensive care unit) and hospital stay were determined. The neurological and radiological outcome, blood loss, the necessity of blood transfusion as well as medical and surgical complications were evaluated. Quality of life was measured using the EQ-5D and SF-36 questionnaires at final follow-up (FU). Results: Average age was 86.5 years (range 80-96 years). Mean AACCI was 7.1, which is classified as severe. In-hospital mortality was nonexistent and no patient showed new permanent neurological deficits after surgery. Average length of hospital stay was 13.8 days and 2 days for ICU. Blood transfusion was necessary in one patient. Three patients developed cardiopulmonary complications postoperatively (2 pneumonia, 1 heart attack). One wound infection occurred. Twenty-five patients were available for final FU with a mean FU of 22 months (range 6-72 months). The quality of life measured by EQ-5D showed a good outcome (0.7 ± 0.1). All SF-36 domains were reduced in comparison with the German population. Solid bony fusion could be achieved in all patients. Conclusion: Our current study confirms that modification of the C1/C2 posterior fusion technique by using intraoperative CT navigation is a safe and effective procedure in the elderly with few complications and preservation of favorable postoperative quality of life. Implant-related complications such as screw loosening or migration could be avoided under navigation guidance. The overall complication rate was 11%. Surgery in the very old should be considered as first-choice treatment.

A012: Management in Acute Traumatic Cervical Spinal Cord Injury

Andrei stefan iencean 1 and stefan mircea iencean 2, 1 clinic emergency n oblu hospital, iasi, romania, 2 gr t popa university of medicine and pharmacy, iasi, romania.

Introduction: Acute traumatic cervical spinal cord injury (SCI) is a very important medical emergency. Many traumatic spinal cord injuries are initially incomplete and the secondary damage completes the destruction of the spinal cord later. Materials and Methods: We present the retrospective analysis of over 1100 cases of acute traumatic cervical spinal cord injuries treated over a 30-year period (1988-2018). These cases of complete or incomplete acute traumatic cervical spinal cord injuries have been treated differently in relation to the evolution of knowledge and the setting standards of treatment. Results: The results were analyzed according to the complete or incomplete lesion; corticoid treatment; surgical timing (early or late surgical decompression); and other types of neuroprotection (correction of hypotension, hypoxia, decrease of intrathecal pressure by lumbar puncture, bone marrow tissue implant, etc). Our patients with acute traumatic cervical spinal cord injuries were treated in this period in relation to the treatments recommended at that time. For example, we used methylprednisolone for a while, or after that we used another corticosteroid scheme; also we have established correlations between the evolution of patients with cervical SCI and the level of the phosphorylated neurofilament NF-H subunit in cerebrospinal fluid as a biomarker. Conclusions: Analysis of over 1000 patients showed better results after early surgical decompression; correction of systemic hypotension and reduction of intrathecal pressure by lumbar puncture; and using an individualized corticotherapy scheme.

OP03: Deformity-Thoracolumbar (Adult) 1

A013: is fresh whole blood superior to blood components transfusion in major spine surgeries a randomized controlled study, shanmuganathan rajasekaran 1 , p. keerthivasan 1 , ajoy prasad shetty 1 , and rishi mugesh kanna 1, 1 ganga hospital, coimbatore, india.

Introduction: Major spine surgeries are associated with significant morbidity that are complemented by increased risks of significant perioperative blood loss with need for multiple blood transfusions. Any possibility to decrease the morbidity and improve outcome is beneficial and should be explored. Transition from fresh whole blood (FWB) to component transfusion in the 1990s was based on convenience rather than on scientific evidence. FWB transfusion has proved superior to blood components in reducing coagulopathic and inflammatory response and improving survival rate in hemorrhagic shock and cardiovascular surgery. However, the primary pathology itself in those studies confound the coagulation and inflammatory markers. Whether this superiority of FWB over component transfusion stands true in major spine surgeries too remain unknown and needs to be evaluated. We did a prospective randomized control study in our hospital from September 2017 to August 2018 to compare the effectiveness of FWB and blood component transfusion in improving clinical outcome and serological parameters in early postoperative period following major spine surgery. Materials and Methods: Sixty-five patients (adolescent idiopathic scoliosis 31, early onset scoliosis 16, neuromuscular scoliosis 15, and neurofibromatosis 3) planned for major spine surgery(>6 levels of fusion, expected blood loss >750 mL, duration of procedure >4 hours) were randomized into 2 groups. FWB group received fresh whole blood, whereas COMP group received components transfusion. Preoperative parameters including demographics, diagnosis, and facial measurements to assess puffiness, intraoperative parameters including level of fusion, type of graft, duration of procedure, volume of transfusion, and blood loss, and postoperative parameters including postoperative drain collection, vitals, duration of oxygen support and ICU (intensive care unit) stay, volume of transfusion, complications, and well-being score were assessed. In addition, biochemical parameters such as PT (prothrombin time), ABG (arterial blood gas), calcium, electrolytes, lactate, and interleukin-6 were also compared between the 2 groups. Results: Mean age of study group was 14.17 years in FWB and 16.48 in components (COMP) group. Mean number of segments fused were 10 in both groups, duration of procedure was 219.52 minutes (FWB) and 206.50 minutes (COMP). Intraoperative blood loss was 926 mL versus 845 mL, and mean transfusions made was 1.90 units versus 1.61 units. Postoperative drain collection was more in FWB (516.84 mL vs 406.19 mL). Duration of ICU stay was less in FWB (40.44 hours vs 45.53 hours), and duration of oxygen dependence is also less (36.34 hours vs 43.29 hours). Mean pH was 7.445 in FWB and 7.397 in COMP ( P < .01). Interleukin-6 was 30.63 and 34.48, respectively. Facial puffiness was present in 18 out of 35 in component group and only 7/30 in FWB group. Other biochemical parameters were similar. Conclusion: Patient transfused with fresh whole blood achieved better clinical outcome in the immediate postoperative period in terms of decreased duration of ICU stay and oxygen dependence and had lesser inflammatory response compared to those who had component transfusion.

A014: Low-Cost Indigenous Implants Versus High-Cost Multinational Company Implants in Treatment of Adolescent Scoliosis Surgery

Rishi m. kanna 1 , ajoy p. shetty 1 , and s. rajasekaran 1.

Introduction: Corrective surgery for adolescent idiopathic scoliosis (AIS) involves huge costs with average per patient cost being approximately $100 000 in the United States. The awareness about the disease and the benefits of surgery are increasingly being recognized in developing countries like India. However, lower per capita income, socioeconomic status, and meagre health care insurance often make the surgeon and the patient to opt for low-cost Indian pedicle screws for deformity correction surgeries (7-10 times less expensive than imported screws). These titanium screws conform to the American Standards for Testing and Materials (ASTM) and are widely used in the Indian subcontinent. However, there is no available data regarding the safety, efficacy, durability, and cost-effectiveness of low-cost Indian screws in comparison to imported screws in scoliosis surgeries. Methods: We performed a retrospective review of case records of consecutive patients who underwent posterior deformity corrective surgery for AIS and completed a minimum of 2-year follow-up. Patients with congenital scoliosis, deformity >100°, pathological curves, need for complex osteotomy, and age >20 years were excluded from the study. Both groups of patients had a uniform surgical technique operated by the same surgical team, pedicle screws placed strategically, and curve correction achieved by rod rotation technique. Patients’ demographics, pre- and postoperative Cobb angle, Lenke curve type, curve flexibility, number of screws used, total vertebral segments fused, and cost analysis based on implants, length of stay, and complications were studied. The patients chose an Indian versus imported implant based on their affordability. Results: Ninety-two patients (female–male = 82:10) formed the study group and were divided into 2 groups: Group A (Indian)—n = 30; and Group B (Imported)—n = 62. The distribution of curves was as follows: Lenke I—40, II—3, III—13, IV—1, V—25, VI—10. The mean age in years was comparable (16.7 ± 3.8 vs 15.2 ± 3.3, P = .05). There was no significant difference in the various study parameters including the mean preoperative Cobb angle: 59.4 ± 14.4° versus 56.8 ± 13.5° ( P = .3990); curve flexibility—39.9 ± 13.5% versus 41.5 ± 14.5% ( P = .6); mean postoperative Cobb angle—21.6° versus 17.8° ( P = .5); mean curve correction achieved—65 ± 23.8% versus 69 ± 25.7% ( P = .46); mean levels fused—10.9 ± 2.3 versus 10.4 ± 2.6 ( P = .36); the screw density ratio—0.68 versus 0.69 ( P = .9); and the mean loss of correction at final follow-up, 2.4° versus 2.6° ( P = .71) between the 2 groups. But the mean cost per patient of $2339.42 in Group A was significantly less than in Group B ($9045.75) ( P < .001). Conclusion: The significantly lower cost Indian pedicle screws provided similar deformity correction, which was maintained at 2 years. The mean levels fused, number of screws used, and screw density ratio was similar in both groups. With concerns about raising health care costs, a low-cost model for spine deformity correction surgery is a welcome need of the hour.

A015: One-Stage Posterior Multiple-Level Asymmetrical Ponte Osteotomies Versus Single-Level Posterior Vertebral Column Resection for Severe and Rigid Adult Idiopathic Scoliosis: A Minimum 2-Year Follow-up Comparative Study

Yangpu zhang 1 and yong hai 1, 1 capital medical university of china, beijing, china.

Introduction: To evaluate and compare the efficacy and safety of one-stage posterior multiple level asymmetrical Ponte osteotomies (MAPO) and single-level posterior vertebral column resection (VCR) in the treatment of severe and rigid adult idiopathic scoliosis (AIS), a retrospective comparison study was performed. Material and Methods: A retrospective comparative study was conducted to evaluate radiological and clinical results in patients with severe and rigid AIS. A total of 38 patients who underwent one-stage posterior MAPO or VCR and fusion surgery at our hospital with minimum 2-year follow-up between February 2009 and November 2015 were enrolled and divided into 2 groups according to the procedures they received. Twenty-six patients were included in MAPO group and 12 patients in VCR group with an average age of 26.65 ± 8.40 years and 27.92 ± 7.50 years. The average follow-up was 30.24 ± 10.55 months. The surgical details and complications were recorded. The radiological parameters before and after the surgery, as well as the final follow-up was collected and analyzed. Clinical outcome including Oswestry Disability Index (ODI) and Scoliosis Research Society-22 (SRS-22) questionnaire scores were obtained preoperatively and at final follow-up. Results: The main curve in MAPO and VCR group were corrected from an average of 98.52 ± 16.50° to 44.11 ± 17.72° and 108.91 ± 16.56° to 56.49 ± 18.82°, with a mean correction rate of 56.72 ± 13.38% and 49.18 ± 12.00% with no significant difference among the 2 groups. No significant loss of correction at final follow-up was found for major curves in both groups. The postoperative coronal and sagittal parameters of the 2 groups were all improved and it showed no significant differences between the 2 groups. The mean operative time and blood loss of VCR group was significantly greater than those of MAPO group. All the clinical scores were significantly improved at final follow-up, with no statistical difference. The incidence of complications in VCR group was 33.33%, which was significantly higher than that in MAPO group. Conclusion: The surgical procedure of multiple asymmetrical Ponte osteotomy is a safe, easy-to-operate, and effective technique that can correct scoliosis and restore the sagittal alignment. It can gain similar correction outcome to VCR, offering the advantages of reduced operation time, reduced blood loss, and greatly reduced the complication and may go a long way toward solving the problems of severe and rigid adult idiopathic scoliosis.

A016: The Role of the Fractional Lumbosacral Curve in Persistent Coronal Malalignment Following Adult Thoracolumbar Deformity Surgery

Alekos theologis 1 , thamrong lertudomphonwanit 2 , lawrence lenke 3 , keith bridwell 4 , and munish gupta 4, 1 university of california–san francisco, san francisco, usa, 2 ramathibodi hospital, mahidol university, bangkok, thailand, 3 columbia university medical center, new york, ny, usa, 4 washington university in st louis, st louis, mo, usa.

Introduction: Achieving appropriate coronal alignment is less reliable in adults with coronal malalignment due to trunk shift ipsilateral to degenerated thoracolumbar scoliosis’ apex. The goal of this study is to compare radiographs/surgical techniques for thoracolumbar deformity with varying severity and direction of coronal imbalance. Material and Methods: Review of adults who underwent posterior spinal fusions to pelvis (≥5 levels) for thoracolumbar scoliosis. Exclusion: revisions, no coronal deformity, thoracic Cobb >30°, and anterior operations. Patients were divided into 3 groups, as proposed by Rao et al: (1) Type A, CSVL (central sacral vertical line) <3 cm; (2) Type B, CSVL >3 cm, and C7 plumb shifted to scoliosis’ concavity; (3) CSVL >3 cm and C7 plumb shifted to scoliosis’ convexity. Radiographic parameters and surgical techniques were compared. Results: A total of 144 patients (male 6; female 118; avgerage age 58 ± 10 years; Type A 87; Type B 19; Type C 18). Type C had significantly greater lumbosacral fractional curves. Twenty-eight percent of Type C were treated with fractional curve TLIFs (transforaminal lumbar interbody fusion), while all, but one, Type B had TLIFs of the fractional curve. Deformity parameters after surgery were similar, except Type C had persistently greater fractional curves/coronal malalignment. All preoperative Type B were appropriately corrected postop. For preoperative Type C, 67% remained Type C and 33% became Type A postoperative. Compared to those who became Type A, persistently undercorrected and malaligned (Type C) patients had significantly greater preoperative lumbosacral fractional curves, greater preoperative coronal Cobb angles, and more commonly involved TLIFs of lumbosacral fractional curves. Conclusion: In adults who underwent primary, posterior-only operations for thoracolumbar spinal deformity, the majority of Type C coronal deformities remained coronally undercorrected and malaligned postoperative. For these patients, an alternative surgical strategy should be considered to more adequately correct lumbosacral fractional curves and maintain and/or restore coronal balance.

A017: Successful Creation of Deployable Preoperative Predictive Risk Calculators for Individual Patient Event-Free Survivorship for Major Complications, Hospital Readmissions, and Unplanned Surgery Following Adult Spinal Deformity (ASD) Surgery

Ferran pellisé 1 , miquel serra-burriel 2 , sleiman haddad 1 , alba vila-casademunt 3 , francisco javier sánchez pérez-grueso 4 , shay bess 5 , emre r. acaroglu 6 , justin s. smith 7 , frank kleinstück 8 , virginie lafage 9 , ibrahim obeid 10 , frank j. schwab 9 , christopher i. shaffrey 7 , ahmet alanay 11 , christopher p. ames 12 , international spine study group issg 9 , european spine study group essg 3, 1 hospital vall d’hebron, barcelona, spain, 2 universitat pompeu fabra, barcelona, spain, 3 vall d’hebron institute of research, barcelona, spain, 4 hospital universitario la paz, madrid, spain, 5 presbyterian st. luke’s/rocky mountain hospital for children, denver, co, united states, 6 ankara artes spine center, ankara, turkey, 7 university of virginia medical center, charlottesville, va, usa, 8 schulthess klinik, zürich, switzerland, 9 hospital for special surgery, new york, ny, usa, 10 bordeaux university hospital, bordeaux, france, 11 acibadem university, istanbul, turkey, 12 university of california san francisco, ca, usa.

Introduction: Accurate preoperative risk stratification in adult spinal deformity (ASD) surgery is indispensable to improve patients’ selection, accordingly adjust surgical invasiveness and optimize outcomes. Few predictive models allow for proper patient selection, adjustment of invasiveness, and patient frailty optimization to predict and reduce postoperative major complications (MC), hospital readmissions (READMIT), and unplanned surgery (UNPLAN). We aim to create accurate predictive models for the occurrence and timing of these MC, READMIT, and UNPLAN following ASD surgery. Material and Methods: Surgically treated ASD patients with >2 year follow-up were identified. Patient demographic, radiographic, operative, baseline patient-reported outcome measures, and complications data were analyzed to build event-free survival curves for MC, READMIT, and UNPLAN, and to create predictive models by means of a random survival forest with 80/20 train/test sets. A total of 101 variables were used to train the models. Goodness of fit was assessed in the test set. Missing value imputation was performed with the miss-Forest package. R software was used for analysis. Results: A total of 1018 ASD patients operated before September 2014 (77.7% women, 55.5 years mean age, 10.7 levels fused segments, 55.5% pelvic fixation, 21.2% 3CO) by 57 surgeons at 24 sites in 5 countries (2 continents), with 2047.9 observation-years, were included in the analysis used to build MC, READMIT, and UNPLAN risk calculating models with proved successful model fit. Missing value imputation was 14.59%. C-statistic value (70.6%) proved successful model fit. Models demonstrate that 87.9% of patients are MC-free at 10 days postoperative, 78.5% at 90 days, and 63% at 2 years. Surgical invasiveness (LIV-pelvic fixation, length of fusion, prior surgery), age, magnitude of sagittal deformity, patient frailty (walking and lifting capacity), and blood loss most strongly predict MC. Surgeon and site most strongly predict READMIT and UNPLAN. Curves show a continued survivorship decrease for event free MC, READMIT, and UNPLAN beyond >2-year follow-up. Conclusion: Risk calculating models for event-free MC, READMIT, and UNPLAN following ASD surgery demonstrate that patient-related factors, >1/3 of which are modifiable, account for 55% of the MC predictive model weight. Surgeon and site represent 4% for MC, but are most relevant for READMIT and UNPLAN.

A018: Rocket Incision and Approach: A Novel Surgical Approach in Posterior Correction of Neuromuscular Scoliosis

Saurabh kapoor 1 , keiran o’boyle 1 , and masood shafafy 1, 1 queen’s medical center, nottingham, uk.

Introduction: Surgical treatment of neuromuscular scoliosis is associated with high risk of infection as incision extends into the nappy area. We describe the safety and efficacy of a new approach developed to reduce these risks. Methods: Data were prospectively collected for a cohort of patients with neuromuscular scoliosis requiring posterior correction in which this novel surgical approach was utilized. A single surgeon at a single institution operated all patients. Technique: Patient is positioned as standard for a posterior approach. Both posterior superior iliac crests (PSIS) are marked on the skin. The positions of the superior gluteal arteries (SGA) are marked bilaterally using pulsations located approximately 1 inch below and at the junction of outer and middle third of the iliac crest. A semilunar line is drawn from one PSIS to the other curving upward with the apex centered at L2/L3. From the apex a vertical line centered on the spine is drawn to the proximal thoracic spine. The overall shape of this looks similar to a rocket or inverted wine glass. The semilunar line is incised directly to through the skin, subcutaneous fat, and the deep fascia. This flap is then raised inferiorly as a whole away from the posterior paravertebral muscles as far as necessary but staying short of the origin of the SGA. Detaching paravertebral muscles distally from middle portion of posterior iliac crest follows subperiosteal exposure. This allows relatively blood less exposure of the posterior pelvis for instrumentation, and when they are reattached, they cover the screws making them less prominent. For closure, the muscles are first reattached to using nonabsorbable sutures or absorbable with long half-life followed by standard closure technique. Results: Study cohort included 4 males and 1 female, with average age of 16.2 years (range 8-19). Average period of follow-up was 15 months (range 3-24). Four patients had cerebral palsy and one Duchene muscular dystrophy. All surgical wounds healed with no complications including superficial or deep infection or metal work prominence. Conclusion: Rocket incision and approach appears to provide a safe and effective alternative approach in posterior correction of neuromuscular scoliosis.

OP04: Biomechanics 1

A019: the effects of added compression on sagittal plane lumbosacral junction rod strain and sacral screw bending moment during in vitro loading, brian p. kelly 1 , anna newcomb 1 , jennifer lehrman 1 , bernardo deandrada pereira 1 , jake godzik 1 , jay turner 1 , and randy hlubek 1, 1 barrow neurological institute, phoenix, az, usa.

Introduction: Variations in load distribution based on surface strains of instrumentation spanning the lumbosacral junction during in vitro loading are often used to evaluate biomechanical effects of different pedicle screw and rod (PSR) configurations. The gold standard for biomechanical comparisons of spinal instrumentation involves the application of pure moment loads to induce bending of the instrumented spine. However, spinal constructs in vivo are subjected to substantial vertical compressive forces due to gravitational loading of upper body mass. The effects of added compressive loads during in vitro bending of the PSR instrumented lumbar spine, as determined by surface strains at the lumbosacral level, are not well understood. The purpose of this study was to analyze the biomechanical differences in lumbosacral rod strain, and sacral screw bending moments during sagittal plane bending, with and without a compressive pre-load. Material and Methods: Fourteen cadaveric specimens were tested in a 6 DOF (degree of freedom) robot under continuous real-time loading in 2 PSR configurations (L2-S and L2-IL) using 5 types of loads: 7.5 N m flexion (FL), 7.5 N m extension (EX), 400 N compression (C), combined C + FL, and combined C + EX. Strain gauges were used to measure rod strains (RS) at L5-S and net sacral screw bending moments (SS). Data were analyzed using one-way repeated-measures ANOVA followed by Holms-Sidak paired analysis ( P < .05). Results: RS significantly increased with L2IL versus L2S (FL: +77%; EX: +65%; C + FL: +46%; C: +40%; P < .004), but without significance during C + EX (+20%, P = .224). SS significantly decreased with L2IL versus L2S (FL: −78%; EX: −81%; C + FL: −52%; C+ E X: −33%; C: −50%; P = .049). Compression loading alone induced significantly greater RS and SS than pure moment FL and EX in both L2S and L2IL groups ( P < .001). Adding C to FL significantly increased RS in L2S (+170%) and L2IL groups (+123%) ( P < .001), and SS in L2S (+86%) and L2IL (+292%) ( P < .001). Adding C to EX significantly increased RS in L2S (+76%; P < .001) and L2IL groups (+27%; P = .043), as well as SS in L2IL (+277%; P < .001) only. Compared to C alone, C + FL increased RS and SS in both groups but without significance, while C + EX tended to reduce RS with significance for L2IL only (−21%; P = .007), and reduce SS with significance for L2S only (−31%; P = .002). In the presence of C, SS was greater and more sensitive to the direction of loading (C + FL vs C + EX) with L2S ( P < .001) versus L2IL ( P = .510), while RS was more sensitive to the direction of loading with L2IL ( P < .001) versus L2S ( P = .430). These differences were not present for magnitudes of RS or SS with pure moment loads (FL vs EX; P > .2). Conclusion: The relative effects of L2IL versus L2S (increased RS and reduced SS) were consistent among all types of loads. However, the additive effects of compression on RS and SS varied with type of instrumentation (L2S vs L2IL) and direction of bending (FL vs EX). Compression loading significantly influences instrumentation performance and can help provide improved understanding of lumbosacral junction load distributions with PSR constructs.

A020: Dual Pedicle and Cortical Screws Using Robotic Navigation Improves Load to Failure in the Osteopenic Lumbar Spine: An In Vitro Biomechanical Analysis

Michael steinmetz 1 , jessica riggleman 2 , jonathan harris 2 , john butler 1 , chelsea wright 1 , mir hussain 2 , bryan ferrick 3 , and brandon bucklen 2, 1 cleveland clinic lerner college of medicine, cleveland, oh, usa, 2 musculoskeletal education and research center (merc), a division of globus medical, inc, audubon, pa, usa, 3 drexel university, philadelphia, pa, usa.

Introduction: Compression fractures due to severe osteopenia may result in kyphotic deformity and/or neurological deficit requiring surgical intervention. Multi-rod reconstruction techniques have been shown to maximize posterior fixation, but at present, utilize a single pedicle screw anchor point to support multiple rods. Robotic navigation technologies have been developed to improve pedicle screw (PS) accuracy and may allow for the insertion of both PS and cortical screws (CS) within the same pedicle, providing 4 points of bony fixation per vertebra. Recent studies have demonstrated the radiographic feasibility for such a dual screw trajectory for posterior lumbar spinal instrumentation; however, the biomechanical characterization of the technique is presently lacking. Investigators quantified the ultimate load to failure and construct stiffness of 4-rod constructs of (1) bilateral pedicle screw and (2) bilateral dual pedicle and cortical screw (PSCS) techniques in an osteopenic model. Material and Methods: Fourteen cadaveric lumbar vertebrae (L2) were divided into 2 groups (n = 7) of similar bone density ( t -score: −2.30 ± 1.38 and −2.16 ± 1.17 for PS and PSCS, respectively). Group 1 was instrumented with PS, and group 2 was instrumented with PS and CS screws within the same pedicle. Operative constructs (L2) included (1) bilateral pedicle screw fixation with 4 rods using rod-to-rod connectors (PS 4-rod); and (2) bilateral PSCS dual screw fixation with 4 rods affixed at PS and CS (PSCS 4-rod). Static compression testing was performed. The construct was connected to four 5.5 mm diameter titanium rods, and the cranial ends of 2 rods were secured to pedicle screws placed within the polyblock. The specimen was loaded in the axial direction to failure at a constant displacement rate of 5 mm/min. Ultimate load to failure (N) and mechanical stiffness (N/mm) were determined. Comparisons were made between groups (significance at P < .05). Results: PSCS 4-rod reconstruction significantly improved the ultimate load-to-failure and mechanical stiffness outcomes. The average load to failure between groups was 892.50 ± 288.15 N and 1798.04 ± 329.23 N for PS 4-rod and PSCS 4-rod, respectively. The average stiffness between groups was 329.67 ± 79.35 and 429.64 ± 84.02 for PS 4-rod and PSCS 4-rod, respectively. A significant difference was noted between groups for both outcome measures ( P < .05). Conclusion: The present study provided the first biomechanical evaluation of a novel dual screw technique using robotic navigation. Four-rod reconstruction with dual pedicle and cortical screws significantly improved pedicle fixation and construct stiffness. Increased stiffness and resistance to failure could be an important component, particularly in patients with severe osteopenia, in hardware maintenance in the absence of fusion, or until bone fragment healing is finalized following stabilization of comminuted bone. Further clinical work is required to determine the efficacy of dual screw fixation in resisting failure in patients with osteopenia.

A021: Functional Requirements for the Long-Term Stabilization of Annulus Fibrosus Lesions

Dmitriy alexeev 1 , benedikt helgason 1 , melanie tschopp 1 , and stephen ferguson 1, 1 eth zurich, institute for biomechanics, zurich, switzerland.

Introduction: The use of thin membranes has been proposed for the repair and stabilization of annulus fibrosus defects. Poly(∊-caprolactone) (PCL) is widely used in the production of bioresorbable electrospun nanofibrous membranes for tissue engineering and regenerative medicine applications. In the context of applying PCL scaffolds to repair annulus fibrosus defects, specific mechanical properties that guide cellular activity and resist deformation are required. Ideally, the mechanical properties of the membrane should match those of the native tissue and remain stable over a relevant time period to allow tissue regeneration and repair. Factors such as increased temperature and hydration, in combination with the temporally changing material properties of PCL, may lead to undesirable alterations in scaffold properties following prolonged exposure. The aims of this study were to define the required properties of electrospun PCL membranes and to study the changes in mechanical properties over a 6-month period in a simulated physiological environment. Material and Methods: To define the required material properties of PCL membranes, a parametric finite element model of the spinal motion segment was created. The dimensions of the model were varied to reflect the natural population variation in disc height, width, and lordosis angle. The range of stress-strain profiles in the outer posterolateral annulus were determined for physiological bending and compression. Based on the predicted material properties, 3 types of PCL scaffolds were produced under variable electrospinning conditions with distinct fiber diameters: (1) 1.5 ± 0.3 μm, (2) 3.5 ± 0.2 μm, and (3) 6.5 ± 0.5 μm. The scaffolds were submerged in DMEM at 37°C for 180 days. Control scaffolds were kept dry at 37°C over the same period. Cyclic extension tests, dynamic scanning calorimetry to determine crystalline content, and infrared spectroscopy to determine ester bond degradation were performed at 0, 14, 30, 60, 90, and 180 days. Results: Required modulus values in the range of 10 to 20 MPa were predicted. These properties were best replicated by the membranes with 3.5 μm and 6.5 μm fiber diameters. No significant difference in the mechanical properties between the submerged and control scaffolds was observed at any time point. A small but significant increase in the crystalline content of the scaffolds was observed at the 180-day time point (∼42% to 47%). All samples were found to have a significant increase in E modulus over the incubation time, which correlated with the change in crystalline fraction. No significant changes in ester bond density were observed. Conclusion: Electrospun PCL membranes represent a promising strategy for annulus fibrosus repair, providing mechanical properties similar to native tissue, with a degree of flexibility in fiber diameter which can be used to tailor cell response. Contrary to expectations, no significant reduction in mechanical properties was observed over a 6-month period, which corresponds to the typical spontaneous tissue healing time reported in literature. Linear degradation of bulk PCL samples by ester bond cleavage has been observed in in vivo rat models. As this behavior was not seen in the submerged scaffolds, we conclude that the in vivo degradation is driven by enzymatic processes.

A022: A Biomechanical In Vitro Study of a Novel Radio Translucent Expandable CF/PEEK Vertebral Body Replacement

Daniel adler 1 and michael akbar 1, 1 ruprecht-karls-university heidelberg, heidelberg, germany.

Introduction: Vertebral body replacement (VBR) combined with dorsal instrumentation is well-established to stabilize tumor related, unstable (>AOSpine A3) vertebral fractures in patients with adequate general condition and life expectancy. The vast majority of implants are manufactured of metallic alloys, which lead to artifacts in postoperative radiological diagnostics as well as in adjunct radiation therapy. The purpose of this study was to evaluate biomechanical data of a novel CF/PEEK (carbon fiber–reinforced PEEK) VBR in combination with a CF/PEEK screw and rod system compared to an established titanium 360° treatment. Material and Methods: Six fresh frozen human thoracolumbar specimens (Th11-L3) were tested in a 6 degree of freedom spine tester in flexion/extension, lateral bending, and axial rotation with pure bending moments of ±7.5 N m. CF/PEEK pedicle screws (6.5 mm) were used in Th11/12 and L1/2 in all tested specimens. Variations in the instrumentations consisted of 2 different 6 mm rod materials (CF/PEEK vs titanium) with and without cross-connectors and 2 different VBR materials (CF/PEEK prototype vs titanium). Results: In lateral bending the ROM (range of motion) of the treated index segments (Th12-L2) was significantly ( P < .05) reduced in all instrumented states compared to native condition (instrumentations: 0.24-0.30° [SD 0.18-0.21] vs native: 11.2° [SD 3.26]). There were no significant differences ( P > .05) between the tested instrumentations in all specimens. In flexion/extension the ROM of the instrumented index (Th12-L2) segments’ was significantly ( P < .05) reduced in all instrumented states compared to segments’ native condition (instrumentations: 0.29-0.35° [SD 0.12-0.31] vs native: 10.3° [SD 2.4]) without significant differences ( P > .05) between the tested instrumentations. In axial rotation the ROM of the instrumented index (Th12-L2) segments’ was also reduced in all instrumented states ( P < .05) compared to native condition (instrumentations: 1.84-3.95° [SD 0.33-0.9] vs native: 4.83° [SD 0.95]). Less rigid CF/PEEK rods in combination with CF/PEEK VBR resulted in the highest ROM (3.95°, SD 0.90), whereas titanium rods with titanium VBR and 2 additional cross-connectors resulted in the lowest ROM (1.84°, SD 0.33). Two additional cross-connectors reduced ROM in axial rotation for all instrumentations independently to VBR or rod material (CF/PEEK vs titanium). VBR’s material (CF/PEEK vs titanium) had only small effect on ROM while posterior rod material (CF/PEEK vs titanium) had a greater effect on ROM in axial rotation. Conclusion: The novel CF/PEEK VBR meets the expectations regarding load capacity and stability. Two cross-connectors are recommended as they reduce ROM independently of rod and VBR material. In axial rotation CF/PEEK rods provide a higher ROM than titanium rods. In lateral bending and flexion/extension there were no significant differences between the tested instrumentations and VBR. The stiffness of rod material affects the ROM rather than the stiffness of VBR material.

A023: Dual Fluoroscopy for Measurement of Spinopelvic Parameters Through the Gait Cycle

Iain s. elliott 1 , keisuke uemura 1 , penny atkins 1 , niccolo fiorentino 1 , nicholas spina 1 , darrel brodke 1 , andrew anderson 1 , and william ryan spiker 1.

Introduction: Spinopelvic parameters measured on lateral long-cassette standing radiographs are performed with the patient in an upright standing posture, in which they are asked to hold a specific postural position for a length of time sufficient to acquire a radiograph that will encompass the entire spine and pelvis. Normal ranges for pelvic tilt (PT), pelvic incidence (PI), and sacral slope (SS) have been defined, and multiple studies have shown that aberrant radiographic metrics correlate with health-related quality of life measures. However, we have yet to understand how these parameters might vary in a patient’s daily life, and whether there might be some ability to compensate when asked to take long-standing cassette films in clinic. It is currently unknown whether spinopelvic parameters vary significantly at other points in a patient’s life, and whether abnormal degrees of motion are associated with pathology. In this study, we used high-speed dual fluoroscopy to quantify in vivo motion of the pelvis to analyze spinopelvic parameters dynamically in healthy volunteers. Material and Methods: Eleven healthy volunteers underwent computed tomography (CT) scans of their pelvis, and walked at their self-selected speed on a treadmill. A previously validated dual fluoroscopy system acquired images of a randomly selected hemi-pelvis and proximal femur. Three-dimensional reconstructions of the hip were generated from the CT image data. Model-based tracking was used to calculate the in vivo position of the hip in each frame of the high-speed fluoroscopic video. PT, PI, and SS were quantified as dynamic parameters throughout the full gait cycle. Results: The range of PI was from 33.9° to 73.9°. Pelvic tilt at static position ranged from 1.72° to 22.2°. The average subject had a variation in the pelvic tilt of 4.7° through the course of the gait cycle and ranged from 1.8° to 10.9°. The maximum that the pelvic tilt changed in any subject was 10.9°, and the least was 1.8°. Conclusion: The sacral slope and pelvic tilt vary throughout the gait cycle, even for healthy individuals. More research is needed to understand the implications of high degrees of pelvic mobility and whether abnormally high or low motion is associated with pathology. Although the sample size is low due to the time-intensive nature of data collection with dual fluoroscopy, the data provided by this study will allow comparison to patients with pathologic sagittal imbalance, and inform interpretation of static radiographs of spinopelvic parameters.

A024: Variations Among Human Spine Segments and Their Relationships to In Vitro Kinematics: A Retrospective Analysis of Experimental Data Including 581 Cervical Motion Segments From 147 Donor Spines

Anna newcomb 1 , jennifer lehrman 1 , bernardo deandrada pereira 1 , neil crawford 2 , and brian p. kelly 1, 2 globus medical, phoenix, az, usa.

Introduction: Kinematic data from in vitro flexibility tests involving cadaveric spines are often used to evaluate medical device performance and to validate finite element models of human spine segments. However, data describing relationships between motion segment features (ie, dimensions of vertebrae and discs, subject height) and kinematics are lacking. The goal of the current study was to retrospectively investigate the relationships between cadaveric cervical spinal motion segments and their biomechanical characteristics, including coupled motion. Materials and Methods: 581 cadaveric cervical motion segments (between C1 and T1) from 147 donor spines (86 males/61 females, range: 20-69 years, mean age 53.5 ± 10.6 years, bone mineral density [BMD] 0.558 ± 0.101 g/cm 2 , mean height 173.4 ± 12.0 cm) were studied. General spine tissue donor information (age, gender, height, and weight at time of death) was obtained from medical histories provided by tissue banks. BMD were obtained from DEXA scans at C4. Dimensions of vertebrae and discs were measured using ImageJ. Kinematic data were retrieved from studies involving intact testing of the fresh cervical spine segments (Occiput-T1), with all tests performed in the same lab using the same protocol. Loads of 1.5 N m were applied while optoelectronically measuring intervertebral rotations in 3 planes (FE, LB, and AR) at all spinal levels. Relationships between donor information (vertebrae and disc dimensions, subject height, weight, gender), bone quality (BMD), and kinematic data (range of motion [ROM], CF LB/AR, and CF AR/LB) were studied using Pearson correlation and multiple regression analyses ( P < .05). Results: Overall values for ROM for intact motion segments were within typical values as reported in the literature (Figure 1). There were significant negative correlations between BMD and ROM, starting at C4-C5 and continuing caudally ( R < −0.18, P < .02). Other significant correlations with ROM include the following: cervical level (all directions of motion: R < −0.18, P < .001]), vertebral body height (FL-EX: R = −0.15, P = .004), vertebral body width (AR: R = −0.22, P < .001; LB: R = −0.28, P < .001), lateral mass height (AR: R = 0.11, P < .05; LB: R = −0.18, P < .03), disc height (FL: R = −0.14, P = .014), donor age (LB: R = −0.11, P < .009), gender (FL-EX and LB: male < female, P < .001), weight (FL-EX and LB: R = −0.10, P < .02), height (FL-EX and LB: R < −0.13, P < .003), and body mass index (BMI; LB: R = −0.132, P = .004). There were significant correlations between both CMs and cervical level (Figure 2), with AR/LB decreasing caudally and LB/AR following the trend of primary motion ratios (LB/AR). There were no correlations between CM and donor information ( P > .4). Multiple linear regression analysis showed that ROM of cervical motion segments can be predicted using relationships between subject cervical level, gender, age, weight, and/or BMD (FL-EX: R = 0.321, P < .001; AR: R = 0.643, P < .001; and LB: R = 0.535, P < .001). Conclusion: Significant relationships exist between cervical spine segments’ dimensions, BMD, and biomechanical properties (ROM and CM) at mid- and lower cervical levels. These relationships are of value especially during the cervical spine model validation process, and in studies focusing on motion preservation.

OP05: Arthroplasty-Cervical

A025: reconsideration of patient selection for cervical disc replacement (cdr) based on minimum 10-year follow-up results, feifei zhou 1 and yu sun 1, 1 peking university third hospital, beijing, china.

Introduction: Cervical disc replacement (CDR) can be complicated by heterotopic ossification (HO) and unwanted ankylosis at the index level, which some authors considered it as an inevitable consequence of cervical nonfusion surgery. Through a tough learning curve of CDR, we noticed that patients with more severe preoperative cervical spondylosis had higher rates of postoperative ossification. Most of indications for different cervical artificial prostheses were described qualitatively, but lack of quantitative criteria. The objective of our study was to explore the quantitative preoperative degenerative changes so as to control the incidence of HO at a relatively low level based on a minimum of 10-year follow-up data. Methods: A retrospective review was performed on 54 patients (66 levels) who underwent Bryan disc replacements by a single group within one institution between December 2003 and August 2008. All patients had at least 10 years of clinical follow-up. Postoperative bone formation at the index level was graded on lateral cervical spine radiographs using the McAfee classification. Preoperative degeneration of the index level was measured by quantitative scoring system based on neutral lateral radiographs including disc height loss, anterior osteophytes with respect to the AP diameter of the corresponding vertebral body, and endplate sclerosis ( Table 1 ). The appearance of ossification of anterior longitudinal ligament (OALL), the range of motion (ROM) at the target level, age, and gender were also collected. Descriptive analyses were presented using means and standard deviations for normally distributed variables and t -test was used to compare between 2 groups (age and ROM). The data sets that were not normally distributed were evaluated with the Mann-Whitney U -test. Fisher’s exact χ 2 test was used to compare the categorical variables (disc height, anterior osteophytes, endplate sclerosis, and OALL) between the groups. According to univariate analysis, the significant factors were analyzed with the multifactor logistic regression analysis. The receiver operating characteristic curve (ROC) was conducted to identify the optimal cutoff point for the significant factors. Results: The study patients had an average age of 44 years, with a mean follow-up of 120.3 months. The overall incidence of postoperative bone formation was 68.2% (45/66 levels). According to the univariate analysis, gender, disc height, anterior osteophyte, and endplate sclerosis were included for multivariate analysis. The multivariate logistic regression identified disc height, anterior osteophyte, and endplate sclerosis as the independent risk factors for postoperative bone formation while the optimal cutoff point for disc height, anterior osteophyte, and endplate sclerosis were 0.5, 1.5, and 1.5 in terms of ROC curve. Conclusion: The overall incidence of postoperative bone formation after CDR was relatively high when patients are followed for greater than 10 years. Most notably, patient selection in preoperative degeneration of the target level plays an important role in postoperative ossification. Rigorous indication, nearly normal disc height, mild anterior osteophyte, and endplate sclerosis should be considered in Bryan disc replacement.

Scoring System of Cervical Disc Degeneration Based on Neutral Lateral Radiographs (Walraevens J, Liu B, Sloten JV, Goffin J. Qualitative and quantitative assessment of degeneration of cervical intervertebral discs and facet joints. Eur Spine J . 2009;18:358-369.)

A026: Clinical Significance of Bone Loss Phenomenon of Vertebral Bodies at the Operative Segment After Cervical Arthroplasty

Dong hwa heo 1 and choon keun park 1, 1 the leon wiltse memorial hospital, suwon, republic of korea.

Introduction: Heterotopic ossification and spontaneous fusion are complications of cervical arthroplasty. In contrast, bone loss phenomenon of vertebral bodies at the operation segment after cervical arthroplasty has also been observed. The purpose of this study is to investigate a potential complication—bone loss of the anterior portion of the vertebral bodies at the surgically treated segment after cervical total disc replacement (TDR)—and discuss the clinical significance. Material and Methods: All enrolled patients underwent follow-up for more than 24 months after cervical arthroplasty using the Prodisc-C, Prodisc-vivo, Mobi-C, Discocerv, and Baguera C disc. Clinical evaluations included recording demographic data and measuring the Visual Analog Scale and Neck Disability Index scores. Radiographic evaluations included measurements of the functional spinal unit’s range of motion and changes such as bone loss and heterotopic ossification. The grading of the bone loss of the operative segment was classified as follows: Grade 1, disappearance of the anterior osteophyte or small minor bone loss; Grade 2, bone loss of the anterior portion of the vertebral bodies at the operation segment without exposure of the artificial disc; or Grade 3, significant bone loss with exposure of the anterior portion of the artificial disc. Results: A total of 247 patients were enrolled in this study. Among them, bone loss developed in 114 patients (Grade 1 in 40 patients, Grade 2 in 38 patients, and Grade 3 in 36 patients). Grade 3 bone loss was significantly associated with postoperative neck pain ( P < .05). Incidence of bone loss was significantly higher in Baguera-C than other types of artificial discs ( P < .05). In contrast, incidence of heterotopic ossification was significantly higher in Prodisc-C ( P < .05). Bone loss was related to the motion preservation effect of the operative segment after cervical arthroplasty in contrast to heterotopic ossification. Conclusion: Bone loss may be a potential complication of cervical TDR and affect early postoperative neck pain. However, it did not affect mid- to long-term clinical outcomes or prosthetic failure at the last follow-up. Also, this phenomenon may result in the motion preservation effect in the operative segment after cervical TDR.

A027: Correlation Between Heterotopic Ossification After Artificial Cervical Disc Replacement and Intervertebral Disc Degeneration

Xiongsheng chen 1 , yin zhao 1 , shengyuan zhou 1 , and bo yuan 1, 1 changzheng hospital, second military medical university, shanghai, china.

Introduction: There were kinds of factors influencing the incidence of heterotopic ossification (HO) after artificial cervical disc replacement (ACDR), while not including reports about the effects of intervertebral disc degeneration on the occurrence of HO. In view of this, the current research retrospectively analyzed the data of 120 patients having accepted ACDR, to investigate the correlation between the HO after ACDR and the degeneration of cervical intervertebral disc. Material and Methods: From January 2009 to June 2016, 120 patients who had undergone ACDR (Discover, Depuy Spine) were included into this study. There were 87 males and 33 females with an average age of 43.83 ± 8.76 years (range 27-67 years). There were 100 patients who had undergone single-level implant and 20 patients double-level implant. Cervical spine flexion-extension X-rays were taken to assess the range of motion (ROM) of the surgical level. HO situation were evaluated by McAfee classification through cervical lateral X-rays. Degeneration degree of patients’ cervical intervertebral discs were evaluated by Pfirrmann grading standards with the preoperative cervical magnetic resonance imaging (MRI). The occurrence and McAfee classification of HO in the replacement segment at the last follow-up were done. According to whether HO occurred, the patients were divided into HO group and non-HO group. ROM and preoperative Pfirrmann score were compared between the 2 groups of patients. Results: All 120 patients were followed-up. The average follow-up time was 52.29 months (13-102 months). The Visual Analogue Scale (VAS) score, Japanese Orthopaedic Association (JOA) score, and Neck Disability Index (NDI) index all improved at the last follow-up. At the last follow-up, a total of 27 patients developed HO, and the incidence of HO was 22.5%. ROM of the HO group (7.40 ± 1.75°) was significantly smaller than that of the non-HO group (9.79 ± 1.40°). Pfirrmann score of preoperative disc degeneration (3.31 ± 1.11) was significantly higher in HO group than in the non-HO group (2.40 ± 0.96). The correlation analysis showed that the Pfirrmann degeneration score of the preoperative replacement segment of the HO group was positively correlated with the postoperative HO McAfee classification ( R = 0.765, P < .01), and negatively correlated with ROM of the replacement segment ( R = −0.866, P < .01). Conclusion: The occurrence of HO after ACDR was correlated with the degree of preoperative degeneration of intervertebral disc. The degree of degeneration of cervical disc in HO group was significantly higher than that of non-HO group. In the HO group, the higher the degree of Pfirrmann degeneration of the intervertebral disc preoperatively was, the higher the McAfee grade at the last follow-up was and the lower ROM of the replacement segment was.

A028: Single-Level Cervical Arthroplasty With ProDisc-C Artificial Disc: 10-Year Follow-up Results in One Center

Yanbin zhao 1 , feifei zhou 1 , and yu sun 1.

Introduction: The aim of this study was to evaluate the clinical and radiographic outcomes of cervical arthroplasty using the ProDisc-C prosthesis. Material and Methods: Clinical and radiographic evaluations, including dynamic flexion-extension lateral images, were performed at baseline and at final follow-up. Results: Twenty-one patients who had single-level ProDisc-C arthroplasty were followed up for a mean period of 122 months. The range of motion at the operated level was 9.1 ± 4.0° at baseline and 6.3 ± 3.7° at final follow-up. Fifteen of 21 levels (71.4%) developed heterotopic ossification: 3 were classified as grade I or grade II heterotopic ossification, 12 were classified as grade III or grade IV heterotopic ossification, according to McAfee’s classification. Two patients developed adjacent segment diseases and received the revision surgeries. Conclusion: ProDisc-C arthroplasty had acceptable clinical and radiographic results at 10-year follow-up. Heterotopic ossification was common after ProDisc-C arthroplasty, which decreased the range of motion.

A029: Clinical and Radiographic Outcomes for a Next-Generation Artificial Cervical Disc: Two-Year Follow-up at 5 Investigational Centers Participating in an US FDA-Approved Study

Richard guyer 1 , dom coric 2 , frank phillips 3 , rick sasso 4 , andew sama 5 , frank cammisa 5 , scott blumenthal 1 , todd albert 5 , and jack zigler 1, 1 center for disc replacement at texas back institute, plano, tx, usa, 2 carolina neurosurgery & spine associates, charlotte, nc, usa, 3 rush university medical center, chicago, il, usa, 4 indiana spine group, carmel, in, usa, 5 hospital for special surgery, new york, ny, usa.

Introduction: Ball-and-socket design cervical disc replacements have been previously described regarding their clinical and radiographic outcomes. A next-generation artificial cervical disc (M6-C ; Spinal Kinetics, an Orthofix Company), which mimics the natural disc morphology and biomechanical characteristics, is currently the subject of a US FDA clinical trial. The unique design of this cervical disc provides 6 independent degrees of freedom including axial compression, flexion-extension, lateral bending, translation, and axial rotation. Materials and Methods: The 5 investigational centers participated in a prospective, multicenter, FDA IDE study of patients with cervical radiculopathy who had not improved after at least 6 weeks of nonsurgical treatment. Skeletally mature patients were implanted with the cervical disc at one level from C3 to C7. Patients were enrolled according to specified entry criteria including preoperative Neck Disability Index (NDI) score of ≥30%, neck or arm pain Visual Analogue Scales (VAS) ≥4, with additional study entry criteria similar to prior FDA IDE studies. Patient evaluation included the NDI, Neck and Arm VAS, neurological assessment, and radiographic assessments. Radiographs were obtained for both quantitative and qualitative assessments using validated methods (QMA; Medical Metrics, Inc). Results: Eighty-three patients (43 males) with a mean age at surgery of 44 years and a mean length of symptoms prior to surgery of 24 months were included in this analysis. Mean blood loss was 31 cc. Surgical time was 83 minutes and mean hospital stay was 0.5 days. Baseline mean NDI was 55.4 and at 2-year follow-up was significantly decreased to 11.3 ( P < .001). There was a significant reduction in VAS neck pain from 7.3 preoperative to 1.3 at 2 years ( P < .001). Mean predominant preoperative arm VAS pain was 7.2 and improved to 0.5 at 2 years ( P < .001). Radiographically there were no migrations, no cases of neurological deterioration as a result of the procedure, and one mild radiolucency at 24 months. Additionally, there were no reports of revision or supplemental fixation during the follow-up period. There was one removal due to suspected infection and one reoperation 1 month postoperatively due to incomplete decompression at the index surgery. The mean index level ROM (range of motion) improved from 7.8° preoperative to 8.1°. Conclusion: The results from this 2-year follow-up of cervical disc replacement subjects implanted with a next-generation design demonstrate the expected clinical outcomes. The results to date may be comparable to, or better than, prior reports of other cervical discs but a limited cohort population does not allow a full comparison at this time.

A030: Influence of Prosthesis Design on the Relationship Between Preoperative and Postoperative Flexion-Extension Range of Motion After Cervical Disc Arthroplasty

Avinash patwardhan 1 , robert m havey 2 , and saeed khayatzadeh 2, 1 department of orthopaedic surgery and rehabilitation, maywood, il, usa, 2 edward hines jr. va hospital, hines, il, usa.

Introduction: Biomechanical goals of cervical disc arthroplasty are to (1) restore physiologic motion and (2) maintain stability at the index segment. In a patient with limited mobility at the index, segment disc arthroplasty should restore normal physiologic motion. Conversely, if a motion segment is hypermobile, the prosthesis should restore stability by eliminating hypermobility. We investigated the influence of prosthesis design on the relationship between preoperative and postoperative FE-ROM (flexion-extension range of motion) after cervical disc replacement using fixed-core, mobile-core, and restrained compressible-core prostheses. Material and Methods: Sixty-Five C5-C6 and C6-C7 motion segments were tested using identical methodology. The flexion-extension motions of cervical segments before and after disc replacement were investigated using 5 different cervical disc prostheses classified into 3 design groups: Fixed-Core (N = 33): PRODISC C, DISCOVER, and PCM; age: 56 ± 10, 19 males/9 female, 28 C5-C6 and 5 C6-C7; Mobile-Core (N = 16): Mobi-C; Age: 42 ± 6, 5 males/3 female, 8 C5-C6 and 8 C6-C7; Restrained Compressible-Core (N = 16): M6 C; Age: 43 ± 5, 5 males/3 females, 8 C5-C6 and 8 C6-C7. Each cervical spine specimen underwent kinematic testing (FE moment = ±1.5 N m, compressive follower preload = 150 N) using the same testing apparatus and protocol. Results: Fixed-Core: FE-ROM after TDA was positively correlated with preoperative FE-ROM ( R 2 = 0.65, P < .0001). Preoperative FE-ROM ranged from 5° to 19°, whereas motion after disc arthroplasty ranged from 2° to 23°. Mobile-Core: FE-ROM after TDA was positively correlated with preoperative FE-ROM ( R 2 = 0.36, P = .014). Preoperative FE-ROM ranged from 6° to 20°, whereas motion after disc arthroplasty ranged from 8° to 24°. Restrained Compressible-Core: FE-ROM after TDA was not correlated with preoperative FE-ROM ( R 2 = 0.17, P = .12). Preoperative FE-ROM ranged from 5° to 21°, whereas motion after disc arthroplasty ranged from 8° to 17°. Conclusion: We observed that disc replacement using either a fixed-core or moving-core design yielded postoperative FE-ROM that was positively and significantly correlated with preoperative FE-ROM ( P < .05). Arthroplasty with the mobile-core prosthesis allowed segmental motions far exceeding the physiologic range, with 6/16 implanted segments yielding motions of 20° or greater. Following disc arthroplasty using a restrained compressible-core prosthesis, segments with limited mobility had physiologic ROM whereas hypermobile segments showed more controlled postoperative motion. These results suggest that a restrained compressible-core prosthesis that provides progressive resistance to angular motion like the natural anatomy can better achieve both goals of restoring physiologic motion without sacrificing stability.

OP06: Trauma-Cervical 2

A031: systemic protein kinase inhibition mitigates immune cells infiltration after spinal cord injury, mohammad-masoud zavvarian 1 , james hong 1 , jian wang 2 , and michael fehlings 1, 1 university of toronto, toronto, ontario, canada, 2 toronto western hospital, university health network, toronto, ontario, canada.

Introduction: Traumatic spinal cord injury (SCI) is a debilitating and multifaceted condition that limits the quality of life for millions of patients worldwide. Despite recent advances in the posttraumatic care, the available treatment options for SCI patients are still limited. The disruption of blood-spinal cord barrier (BSCB) by the mechanical trauma is a major challenge that limits the potency of most SCI treatments. Infiltration of pro-inflammatory immune cells following the BSCB disruption leads to further permanent damage to the injury epicenter. Therapeutic stabilization of BSCB can potentially attenuate the immune cells migration and improve SCI recovery. Protein kinase C (PKC) is a key regulator of the junctional complexes in BSCB, and its inhibition has been shown to enhance the integrity of the BSCB in non-SCI injury models. The aim of this study is to analyze the effect of PKC inhibition using midostaurin—a clinically approved protein kinase C inhibitor—on BSCB integrity, and to determine their efficacy as a treatment for SCI. Materials and Methods: SCI was induced in 12 Wistar rats using the clip-compression injury model at C6-7. The injured rats were randomly assigned to 2 cohorts (n = 6), receiving either midostaurin or vehicle control. In addition, 6 laminectomized shams were used to constitute a noninjured cohort. All rats were sacrificed at 24 hours postoperation, and the total RNA and protein were extracted from the spinal cord to evaluate the molecular changes. Western blotting was used to assess the phosphorylation of downstream target molecules. Differentially expressed genes were identified using reverse transcription qualitative polymerase chain reaction. Multiplex Luminex assay was used to examine the inflammatory response after SCI. Results: Administration of 25 mg/kg midostaurin reduced the phosphorylated GSK3 and STAT3 at the injury epicenter (1 day postinjury). This demonstrates the penetrance of the midostaurin into the spinal cord. The transcriptional analysis reveals downregulation of adhesive and migratory genes including JAM2, THY1, and ITGB1. This ultimately leads to the mitigation of pro-inflammatory markers, such as fractalkine, IL-1a, and IL-5 at 1-day postinjury. Conclusions: This study demonstrates that systemic protein kinase C inhibition is an effective strategy for preventing secondary SCI damage, which can have a significant impact on the enhancement of neuroprotective regime applied on traumatic SCI. In the future, a dose-response study will be performed to determine the most effective dosage of midostaurin for reducing BSCB permeability after SCI. The results obtained from this study will further our understanding of molecular changes in SCI and enhance the availability of clinical treatments in order to improve the quality of life for SCI patients.

A032: Early Surgical Decompression Improves Neurological Outcome After Complete Traumatic Cervical Spinal Cord Injury: A Meta-Analysis

Paula valerie ter wengel 1 , p. c. de witt hamer 2 , j. c. pauptit 2 , n. a. van der gaag 3 , f. c. oner 4 , and w. p. vandertop 2, 1 slotervaart hospital, amsterdam, netherlands, 2 amsterdam umc, vumc, amsterdam, netherlands, 3 lumc, the hague, netherlands, 4 umcu, utrecht, netherlands.

Introduction : In patients with traumatic spinal cord injury (tSCI), a distinction in surgical urgency is made on the basis of severity of initial neurological injury. The optimal timing of surgical decompression, as well as its impact on neurological recovery, is as of yet undetermined. This study addresses neurological improvement after early and late surgery for complete and incomplete cervical traumatic spinal cord injury. Material and Methods: A systematic search retrieved 15 publications of observational studies reporting outcome measurements after surgery in 1.126 patients with cervical tSCI from PubMed and Embase databases. Surgery was considered early within 24 hours, and late thereafter. An improvement of at least 2 grades on the ASIA (American Spinal Injury Association) scale was considered clinically meaningful. The MOOSE guidelines were followed. Improvement rates were summarized using individual patient data in a Bayesian random effects model and compared for those with complete and incomplete tSCI after early and late surgery. Results: In patients with complete cervical tSCI (n = 422), improvement was more frequent after early surgery than after late surgery (respectively, 22.6%, 95% confidence interval [CI] = 16.6% to 28.7%, and 10.4%, 95% CI = 5.6% to 15.8%; odds ratio [OR] = 2.6 [95% CI = 1.4-5.1]). Whereas in patients with incomplete cervical tSCI (n = 636), improvement was similar between early and late surgery (respectively, 30.4%, 95% CI = 19.8% to 41.6%, and 32.5%, 95% CI = 21.4% to 45.8%; OR = 0.9 [95% CI = 0.4-1.9]). Conclusion: These data suggest a paradigm shift in the treatment of patients with complete cervical tSCI, as surgical decompression within 24 hours is more frequently associated with clinically meaningful improvement. In incomplete cervical tSCI, neurological outcome is similar between early and late surgery.

A033: Does the Cervical X-Ray and CT Provide False Security After Trauma? Sensitivity and Specificity of X-Ray, CT, and MRI in Patient With Cervical Trauma

Sebastian bigdon 1 , pascale amrein 1 , sven hoppe 1 , moritz deml 1 , aristomenis exadaktylos 1 , lorin benneker 1 , and christoph albers 1, 1 inselspital university of bern, bern, switzerland.

Introduction: Trauma with consecutive neck pain is a common reason for admission to the emergency department. The Canadian C-Spine rules and the NEXUS criteria are well accepted to guide decision making toward radiographic workup. The modality of imaging depends on the patients’ history and clinical symptoms; however, there is no consensus whether conventional X-ray, computed tomography (CT), or magnetic resonance imaging (MRI) is superior to confirm or rule out C-spine injuries. Materials and Methods: We retrospectively reviewed 4110 consecutive patients with neck pain after a trauma that were admitted to the emergency department (ED) of our level 1 trauma center. The available imaging as well as the modality of imaging obtained during the presentation in ED was documented. Thereafter, radiographic findings documented by the radiologist were compared to the report from the spine surgeon, and the presence or absence of any kind of injury was compared between the 2 reports. In case of disagreement between the 2 reports, 2 orthopedic surgeons specialized in spine surgery blinded to the former report independently reviewed the images to find a consensus. Results: In 540 patients primary conventional X-ray of the C-spine was performed. An injury was detected in 10 patients (2%). In 390 patients additional CT scans or MRI was conducted. The evaluation of all acquired images revealed that 32 injuries to the cervical spine were missed on plain films leading to a 24% sensitivity of conventional X-ray. There were no false positive injuries diagnosed on conventional X-ray as compared to CT or MRI, resulting in a specificity of 100%. In 2193 patients, primary CT scan was performed. One hundred sixty-four patients had an injury of the C-spine (7%). Ninety out of the 2193 patients received additional MRI scans (4%) revealing 10 additional injuries, of which 5 required immediate surgical therapy. One initially suspected injury on CT could not be confirmed on MRI. The resulting overall sensitivity of CT was 94% and specificity of 99%, respectively. Sixty-three patients underwent MRI without previous X-ray or CT to assess possible C-spine injuries. Three injuries were found. A total of 160 patients had MRI with additional CT and/or X-ray. Thirty-four injuries were detected on MRI with no missed injury and no false positive report as compared to the other 2 imaging modalities, leading to a 100% sensitivity and specificity of MRI. Conclusion: Our study is to this point the largest evaluation of patients with traumatic neck pain admitted to a level 1 trauma center. We found that X-ray examinations have a poor sensitivity to find injuries to the cervical spine, missing nearly 7 out of 10 injuries in this series. While CT scan has a very good sensitivity and is routinely performed to confirm or rule out an injury, there are still relevant injuries missed using only the CT. In our retrospective analysis, the MRI was the best diagnostic modality with a sensitivity and specificity of 100% to detect C-spine injury following trauma.

A034: Temporary Atlantoaxial Segmental Fixation and Reduction for Grauer Type IIB Dens Fractures

Nanjian xu 1 and weihu ma 1, 1 sixth hospital of ningbo, ningbo, china.

Introduction: The treatment of Grauer type IIB dens fractures not amenable to anterior screw fixation remains a challenge for spinal surgeons because of preservation of atlantoaxial rotation. Although most of the atlantoaxial fixation techniques used to address dens fractures achieve satisfactory stability and bone fusion, atlantoaxial rotation is rarely preserved. The purpose of this study is to assess the clinical results of temporary atlantoaxial segmental fixation and reduction for Grauer type IIB dens fractures, which may traditionally require posterior atlantoaxial fusion. Material and Methods: From May 2010 to June 2015, 23 patients with Grauer type IIB dens fractures not amenable to anterior screw fixation were enrolled and treated using 1-stage temporary atlantoaxial segmental fixation and reduction without fusion. There were 15 males and 8 females, aged from 14 to 68 years with an average of 47.3 ± 16.19 years. The internal fixations were removed after the consolidation of the fractures was radiologically confirmed. Dynamic CT (computed tomography) was performed >1 year after implant removal to evaluate atlantoaxial rotation. Visual analogue scale (VAS) and Neck Disability Index (NDI) were used to evaluate the clinical efficacy. Results: Two patients had numbness of occipital cervical, and both of them recovered within 2 months. All patients were followed-up. The follow-up time ranged from 18 to 25 months (average 21.61 ± 2.35). The healing time of bone fusion ranged from 6 to 10 months (average 8.26 ± 1.25). At a mean of 8 months after the initial operation, fracture union was confirmed and implants were removed. There were no complications associated with instrumentation. Fracture healing was observed in 23 patients and the instrumentation was removed. After removing the instrumentation, the NDI had improved ( P < .01). The average preoperative VAS score was 6.78 ± 0.67, while the score of last follow-up was 0.43 ± 0.51, with statistically significant differences ( P < .01). The mean atlantoaxial rotation was 15.80 ± 5.16° to the left and 15.80 ± 5.31° to the right. The average total atlantoaxial rotation was 31.60 ± 9.87°. Conclusion: Temporary atlantoaxial segmental fixation and reduction could effectively avoid the loss of atlantoaxial rotation caused by posterior atlantoaxial fusion.

A035: Description of a New Odontoid Fracture Variant: Proposal for a Modification of the Anderson and D’Alonzo Odontoid Fracture Classification

David gendelberg 1 , haitao zhou 1 , amy cizik 1 , nathan wigner 1 , christina cheng 1 , quynh nguyen 1 , and carlo bellabarba 1, 1 university of washington, harborview medical center, seattle, wa, usa.

Introduction: Odontoid fractures are common cervical spine injuries in the adult population. The classification system described by Anderson and D’Alonzo is the most frequently used to describe odontoid fractures. Type 3 odontoid fractures are usually amenable to conservative management and type 2 fracture management is controversial. We have observed an odontoid fracture variant that consists of an odontoid fracture and a concurrent fracture in the coronal plane that separates the pars-interarticularis from the rest of the C2 body. Therefore, the purpose of this paper is to describe this odontoid fracture variant and designate it as a type 4 odontoid fracture in the Anderson and D’Alonzo classification. Materials and Methods: A more precise distinction between odontoid fractures with and without a fracture that separates the pars-interarticularis from the C2 body is proposed. Criteria that define this fracture variant include the following: (1) coronal fracture line separating pars-interarticularis from rest of the C2 body; (2) any type of odontoid fracture; and (3) unilateral versus bilateral pars involvement. To evaluate for reproducibility, a Cohen κ test with a power analysis was performed to evaluate interobserver reliability among 2 spine surgeons for the proposed classification system modification. Results: Sixteen odontoid fracture variants were reviewed, of which 13 were acutely treated operatively. Of the 3 fractures treated conservatively, 2 cases failed and displaced and 1 case failed halo management and was subsequently treated operatively. Cohen κ test for interobserver reliability was found to be 0.686, indicating “good” agreement. Conclusion: Odontoid fractures in which one or both pars-interarticularis are separated from the vertebral body are clinically distinct fracture patterns, which differ from the other odontoid fracture types in the Anderson and D’Alonzo classification. These fractures are relatively common. In one study, where they were described as “complex C2 fractures,” and they compromised 19% of all C2 fractures. We feel that this odontoid fracture variant indicates a greater degree of instability and may therefore benefit from surgical intervention. Furthermore, identification of this fracture variant has been reproduced among different surgeons. In light of its frequency and its influence on clinical decision making we believe that it should be designated as a type 4 odontoid fracture.

A036: Radiologic Factors to Predict Injury of Transverse Atlantal Ligament in Unilateral Sagittally Split Fracture of C1 Lateral Mass

Jong-beom park 1 and do-gyun kim 1, 1 uijeongbu st. mary’s hospital, the catholic university of korea, uijeongbu, republic of korea.

Introduction: Unilateral sagittally split fracture (USSF) of C1 lateral mass (LM) is a variant type of C1 atlas fracture. Recently, it is recognized as unstable fracture, which causes late deformity of occipitocervical junction that requires extensive reconstructive surgery. Since USSF of C1 LM is rare, its definite treatment guideline has not been established. The integrity of transverse atlantal ligament (TAL) is a key factor to determine whether to treat surgically or nonsurgically in C1 atlas fracture. However, no information is available about which type of USSF of C1 LM is associated with injury of TAL. Therefore, we performed the current study to investigate radiologic factors to predict injury of TAL in USSF of C1 LM. Material and Methods: Twenty-six consecutive cases of USSF of C1 LM were included from 5 trauma centers of tertiary university hospitals. The fractures associated with other cervical spines, such as C2 and occiput, were excluded from the study. The mean age was 52 years. Sixteen were males and 10 were females. Two radiologists determined presence of TAL injury in MRI (magnetic resonance imaging) using Dickman’s classification and divided into 2 groups: TAL injury and TAL intact. If the results of 2 judgements were not identical, the third radiologist reevaluated. Three spine surgeons measured radiologic parameters and the averages were used as final results: Total LM displacement (LMD), unilateral LMD at fracture side, atlanto-dental interval (ADI), fracture gap, clivus canal angle (CCA), atlanto-occipital joint axis angle (AOJAA), and basion-dens interval (BDI). The radiologic results were compared between 2 groups. The incidence of associated other C1 fractures was also investigated and compared between the 2 groups. Results: Sixteen were TAL injury group (9 type I and 7 type II) and 10 were TAL intact group. Total LMD and unilateral LMD at fracture side were higher in TAL injury group than TAL intact group (5.9 mm vs 1.2 mm, P < .001, and 4.3 mm vs 1.0 mm, P < .001, respectively). ADI and fracture gap were higher in TAL injury group than TAL intact group (2.0 mm vs 1.5 mm, P < .05, and 6.9 mm vs 2.1 mm, P < .001, respectively). However, CCA, AOJAA, and BDI were not statistically different between the 2 groups (155.6° vs 154.9°, P = .824; 107.8° vs 105.9°, P = .676; and 4.4 mm vs 4.2 mm, P = .751. Total LMD was positively correlated to unilateral LMD at fracture side (CC = 0.937, P < .001), ADI (CC = 0.449, P < .01), and fracture gap (CC = 0.658, P < .001), but not CCA, AOJAA, and BDI (CC = −0.221, P = .279; CC = −0.042, P = .837; and CC = −0.138, P = .502). Incidence of associated other C1 fractures was higher in TAL injury group that TAL intact group (87% vs 20%, P < .001). Conclusion: Our results suggest that total LMD more than 5.9 mm and unilateral LMD at fracture side more than 4.3 mm are radiological factors to predict injury of TAL in USSF of C1 LM. For such cases, we recommend early surgical stabilization to avoid coronal and sagittal malalignment of occipitocervical junction, resulting in unsatisfactory clinical outcomes.

OP07: Infections 1

A037: hemoglobin a1c as a predictor of surgical site infection following single-level lumbar/lumbosacral posterior fusion in patients with diabetes, dong wuk son 1 , geun sung song 1 , sang weon lee 1 , soon ki sung 1 , jun seok lee 1 , and doo kyung son 1, 1 pusan national university yangsan hospital, pusan, republic of korea.

Introduction: Diabetes mellitus (DM) is a prevalent disease of glucose dysregulation that has been associated with an increased risk for postoperative infection following spine surgery. The status of preoperative blood glucose management may affect the risk of surgical site infection (SSI). In the present study, we evaluated the association between preoperative glycemic control as indicated by hemoglobin A1c (HbA1c) in patients with diabetes and incidence of postoperative SSI following single-level lumbar/lumbosacral posterior fusion. Furthermore, we calculated a threshold level of HbA1c above which the risk of SSI after posterior lumbar/lumbosacral arthrodesis increases significantly in diabetic patients. Material and Methods: From January 2009 to December 2015, a total of 92 patients who underwent single-level lumbar/lumbosacral posterior fusion with a diagnosis of DM who had a preoperative HbA1c recorded within 4 weeks of surgery were included in the study. Patients were divided into 2 groups according to whether they had SSI, and then demographic/clinical data were compared. A receiver operating characteristic (ROC) and area under the curve (AUC) analysis was conducted to define the cutoff value of HbA1c above which the risk of SSI was significantly increased. Including this value, potential variables were verified by multiple logistic regression analysis. Results: Twenty-four patients were treated for SSI and 68 patients maintained noninfectious condition within 1 year. Three of the 24 (12.5%) patients developed SSI in the deep layer requiring operative irrigation and debridement. The preoperative HbA1c value was significantly higher in patients with SSI (6.8%) than in those without SSI (6.0%; P = .008). The results of ROC analysis determined that HbA1c ≥6.9% could serve as a threshold for significantly increased risk of SSI ( P = .003, AUC = 0.708, sensitivity = 62.5%, specificity = 70.6%). After adjusting for potential confounders, there was a significant association between preoperative HbA1c and occurrence of SSI ( P = .008, odds ratio = 4.500, 95% confidence interval = 1.486-13.624). Conclusion: In patients with diabetes, the preoperative glycemic control as indicated by HbA1c is an independent risk factor for SSI following single-level lumbar/lumbosacral posterior fusion. Particularly when preoperative HbA1c exceeded 6.9%, the risk of SSI significantly increased.

A038: Factors Associated With an Increased Risk of Developing a Postoperative Infection Following Spine Surgery

Mina aziz 1 , greg mcintosh 2 , michael johnson 3 , charles fisher 4 , michael weber 1 , and michael goytan 3, 1 mcgill university, montreal, quebec, canada, 2 canadian spine outcomes and research network, mandrake, ontario, canada, 3 university of manitoba, winnipeg, manitoba, canada.

Introduction: Postoperative infection is a serious complication of spine surgery and can contribute to the strain on the health care system’s resources; some studies have estimated the cost of such an infection to be $200 000 per patient. The purpose of this study is to determine what factors affect the risk of developing postoperative infection. We hypothesize that female gender, smoking, diabetes, having thoracolumbar procedures, having a neurological deficit, increased age, body mass index (BMI), American Society of Anesthesiologists (ASA) score, blood loss, and number of operative levels increase the patients’ risk of developing a postoperative infection. Material and Methods: A retrospective review of prospectively collected data within the Canadian Spine Outcome Registry Network (CSORN) was conducted. Data were analyzed using IBM-SPSS. ANOVA was used to analyze continuous variables, while odds ratios were used to analyze categorical variables. Multivariable logistical regression analysis was conducted (odds ratios) to determine any association between the outcome and independent factors. Significance level was P < .05. Results: There were 7747 patients identified from the registry that had completed at least 12 weeks of follow-up. There were 199 infections recorded representing a 2.6% risk of infection. There were no association found between the risk of developing a postoperative infection and gender, age, smoking status, neurological status, and diabetes. Having a higher ASA score was associated with an increased risk of developing a postoperative infection (adjusted odds ratio [OR] = 1.427, 95% confidence interval [CI] = 1.123-1.812, P < .004). Increased intraoperative blood loss was associated with an increased risk of developing a postoperative infection (adjusted OR = 1.0, 95% CI = 1.0-1.001, P < .008). Increased number of operative levels was associated with an increased risk of developing a postoperative infection (adjusted OR = 1.076, 95% CI = 1.003-1.154, P < .004). Having an elevated BMI showed a trend toward an association with developing postoperative infection but did not reach statistical significance (adjusted OR = 1.025, 95% CI = 0.999-1.052, P < .056). Undergoing thoracolumbar procedures also showed a trend toward an association with developing postoperative infection but did not reach statistical significance (adjusted OR = 1.517, 95% CI = 0.953-2.413, P < .079). Conclusion: There is a 2.6% overall rate of postoperative spine infection across 20 Canadian centers. The factors that were associated with an increased risk of developing a postoperative infection were higher ASA scores, increased blood loss, and having more operative levels. Undergoing thoracolumbar procedures and having a higher BMI showed a trend toward association that did not reach statistical significance. This study establishes a benchmark against which the effectiveness of future interventions to reduce infection can be compared.

A039: Prevention of Surgical Site Infection in Major Spinal Surgery: Evidence Update With Focus on Wound Care

Goldenberg yoni 1 , martin k hunn 1 , susan liew 1 , and jin w tee 1, 1 alfred hospital, melbourne, victoria, australia.

Introduction: Surgical site infection (SSI) is a major strain on health care resources. Rates of SSI in spinal operations are reported to be anywhere between 0.6% and 16%, each with huge economic burden and morbidity to the patient. While the literature appears to suggest that major spine surgery (≥3 levels) increases the risk of SSI, there has been significant variability in the techniques reported in the literature aimed at preventing these wound complications. This review has considered new research and systematic reviews over the last 18 years that focus on wound care techniques which would reduce SSIs, in particularly in major spine surgery, and whether or not those should be incorporated in future guidelines. The domains that were considered are (1) preoperative bathing, (2) skin preparation, (3) skin incision prophylaxis, (4) fascia and skin closure techniques, (5) dressings, and (6) use of drains. Material and Methods: This review was conducted in accordance with the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines. For each domain, electronic databases and reference lists of key articles were searched from January 1, 2000, to August 31, 2018, to identify studies meeting inclusion criteria. Results: Initial search combined for all domains yielded 818 studies. After applying the study inclusion criteria 52 studies were retrieved. Examining independently each domain, 20 publications were selected. The review has revealed mounting evidence in support of preoperative chlorhexidine gluconate bathing and nasal screening for Staphylococcus aureus preoperatively. Statistical significance was not always demonstrated and none were focused on major spine surgery. The most efficacious skin preparation is not established in the literature with some studies showing superiority of chlorhexidine-alcohol solution over aqueous povidone iodine. Other fields in the literature further support alcohol-based antiseptics. There has been strong recommendation for the use of antibiotic prophylaxis. Prolonged antimicrobial prophylaxis, defined as >24 hours after first preoperative dose, does not reduce SSI risk, and major spine surgery was not studied separately in relation to risk-reduction stratification. Limited level I evidence was available for wound closure techniques with only a single systematic review. In that study there was felt to be a lack of evidence for optimal closure technique in posterior spinal surgery. Lower quality studies demonstrated significant reduction in SSI using 2-octyl-cyanoacrylate. No data were available to support a particular technique of fascia closure; however, in other specialties, interrupted and continuous suture fascial closure were found to demonstrate no difference in terms of wound infection or dehiscence while antimicrobial sutures significantly reduced SSI in these cohorts. Evidence regarding dressings and drains in reducing SSI are limited but emerging evidence suggests some utility in those treated with silver-impregnated dressings. Drains have demonstrated to neither increase nor reduce the risk of SSI. There is no evidence to support the use of prophylactic antibiotics while the drains are in situ. Conclusion: This review enables tertiary spine centers to structure a comprehensive wound care plan that is evidence based while acknowledging that more high-quality research is required in order to validate such wound care plans in reducing institutional SSI in major spine surgery patients.

A040: Application of Simultaneous PET-MR Imaging in Pyogenic Spondylodiscitis: Preliminary Study

Ikchan jeon 1 , eun jung kong 1 , and chul pyo hong 2, 1 yeungnam university hospital, daegu, korea, 3 catholic university of daegu, daegu, korea.

Introduction: There is still no definite correlation between follow-up magnetic resonance (MR) imaging findings and clinical status for monitoring treatment response in spinal infection. Furthermore, several factors related with general condition can have an influence on blood inflammatory indexes. Recently, fluorine-18 fluorodeoxyglucose positron emission tomography (F-18 FDG PET) shows great potential as a new option. Simultaneous F-18 FDG PET and MR (PET/MR) imaging make us to expect a huge synergic effect in a view of anatomic and metabolic advantages. Material and Methods: Prospective study. From January 2017 to February 2018, 34 patients with pyogenic thoracolumbar spondylodiscitis were enrolled. Decision making for treatment response (good or poor response) was performed based on clinical symptoms, blood inflammatory marker (erythrocyte sedimentation rate [ESR] and C-reactive protein [CRP]), and 1 or 2 times of PET/MR imaging in the patients after at least 3 weeks of antibiotic therapy. We compared the differences of clinical data including ESR, CRP, and PET/MR imaging between good-response group (n = 28, group A) and poor-response group (n = 16, group B) (10 patients of group B were also included to group A after a successful treatment), and analyzed the recurrence rate at least 6 months of follow-up period in group A. Results: Good-response group showed lower ESR (45.64 ± 29.33 vs 72.31 ± 29.20), CRP (0.95 ± 1.38 vs 2.83 ± 2.64), and SUV max (4.15 ± 1.42 vs 6.84 ± 2.23) in group A than group B ( P < .05). There was a difference in the distribution of F-18 FDG uptake depending on treatment response. F-18 FDG uptake was limited to destroyed disc in group A compared with the broad involvement to vertebral body in group B. SUV max was the most reliable diagnostic method with cutoff value 5.14, sensitivity 93.8%, specificity 82.1%, positive predictive value 75%, and negative predictive value 95.8%. There was one patient with recurrence during the follow-up period (1/28, 3.6%). We found the possibility of DWI and ADC as the specific MR sequences which can reflect the result of PET. Conclusion: PET/MR imaging is an independent valuable method that is unaffected by other conditions with higher sensitivity and negative predictive value for evaluating treatment response in pyogenic spondylodiscitis. We need to obtain the best MR sequences that can reflect the result of PET to be more helpful.

A041: Multidisciplinary Management of Pyogenic Spondylodiscitis: Epidemiological and Clinical Features, Prognostic Factors, and Long-Term Outcomes

Enrico pola 1 , giovanni autore 1 , valerio cipolloni 1 , luca piccone 1 , massimo fantoni 1 , and francesco ciro tamburrelli 1, 1 catholic university of the sacred heart, rome, italy.

Introduction: Pyogenic spondylodiscitis (PS) is a severe infective disease burdened by high morbidity rates. Although there is rising incidence, the proper management of PS is still much disputed. Objectives of this study were to delineate the clinical features of PS and to analyze the prognostic factors and the long-term outcomes of a large population of patients. Material and Methods: A total of 207 cases of PS treated from 2008 to 2016 with a 2-year follow-up were enrolled. Clinical data from each patient were reported. The outcomes was initially the rate of healing without residual disability and secondary outcomes the length of stay, healing from infection, death, relapse, and residual disability. Binomial logistic regression and multivariate analysis were used to evaluate prognostic factors. Results: Median diagnostic delay was 30 days and the rate of onset neurological impairment was 23.6%. Microbiological diagnosis was established in 155 patients (74.3%), and the median duration of total antibiotic therapy was 148 days. Orthopedic treatment was conservative for 124 patients and surgical in 47 cases. Complete healing without disability was achieved in 142 patients (77.6%). Statistically confirmed negative prognostic factors were negative microbiological culture, neurologic impairment at diagnosis, and underlying endocarditis ( P ≤ 0.05). Healing from infection rate was 90.9%, while residual disabilities occurred in 23.5%. Observed mortality rate was 7.8%. Conclusion: The leading predictive factor for successful treatment is microbiological diagnosis. Multidisciplinary management and early diagnosis are necessary to identify underlying aggressive conditions and to reduce neurological complications associated with poorer long-term outcomes. Despite good prognosis rates, PS may lead to major disabilities still representing a challenging disease.

A042: One-Stage Reconstruction Surgery in Tuberculous Spondylitis With Kyphotic Deformity

Asrafi rizki gatam 1 , phedy phedy 1 , fachrisal ipang 1 , ajiantoro aji 1 , and luthfi gatam 1, 1 fatmawati general hospital, jakarta selatan, indonesia.

Introduction: In managing tuberculous spondylitis with kyphotic deformity, 2-stage combined anterior-posterior approaches were performed to reconstruct both anterior and posterior column. Anterior procedure is known for increase morbidity due to very extensive approach such as thoracotomy or thoracophrenicolumbotomy. Single -stage posterior only with lateral extracavitary approach for anterior column reconstruction is one of the options in managing the cases with less morbidity. The objective of this study is to evaluate clinical outcome and radiologic result kyphotic deformity patients who were treated using one-stage reconstruction surgery. Method: This is a prospective study of tuberculous spondylitis with kyphotic deformity managed with single-stage anterior and posterior reconstruction with lateral extracavitary posterior only approach. Comparison of pre- and postoperation Visual Analogue Scale (VAS), Oswestry Disability Index (ODI), kyphotic angle, and sagittal balance were measured in all the cases. Result: There were 20 tuberculous spondylitis cases managed with this technique. All of the cases were located on thoracal or thoracolumbar junction area. The mean age of the patients was 37.1, 12 males and 8 females. Procedures were performed with lateral extracavitary approach. The mean estimated blood loss and length of surgery were 750 mL and 194 minutes. The mean preoperation local kyphotic angle was 54.1°, and regional kyphotic angle was 37.5°. The mean postoperation local kyphotic angle was 23.9°, and regional kyphotic angle was 16.8°. Two patients had postoperative hypoesthesia in the subsequent dermatome level. All of the patients have good clinical outcomes with no neurologic deficit, with mean 1 year postoperation VAS of 0.3 and ODI of 6.7. Radiology of 1-year follow up showed good fusion on the anterior segment of the spine. Conclusion: Single-stage posterior only with lateral extracavitary approach for anterior column reconstruction and posterior instrumentation is a viable alternative method to treat kyphotic deformities. This surgical procedure will produce a good alignment, strong fixation, better fusion, and reduced morbidity with 1-stage surgery.

OP08: Biomechanics 2

A043: sequential changes in lumbar lordosis and segmental stability following lateral interbody cage placement, smith-peterson osteotomy, and anterior longitudinal ligament release, richard k. hurley jr 1 , amy a. claeson 2 , jason a. inzana 2 , anup gandhi 2 , and zachary child 3, 1 brooke army medical center, fort sam houston, tx, usa, 2 zimmer biomet, westminster, co, usa, 3 tahoe orthopedic institute, south lake tahoe, ca, usa.

Introduction: Interbody cage systems can be used in isolation to achieve lumbar lordosis correction, but can also be deployed using techniques to shorten the posterior or lengthen the anterior spinal column to yield even larger corrections. The Thomasen pedicle subtraction osteotomy (PSO) yields ∼30° of correction, but with high degree of difficulty and surgical complication rates. 1,2 A lateral lordotic cage with Smith-Petersen Osteotomy (SPO), a hyper-lordotic lateral cage with anterior longitudinal ligament (ALL) release, 3,4 or a lateral cage with combined techniques 3 show potential for substantial lordosis correction. The removal or release of local spinal anatomy, however, can increase segmental motion and may inhibit fusion. The objective of this biomechanical cadaver study was to identify the lordosis correction and resulting segmental stability achieved with implantation of lateral lordotic cages of increasing angle coupled with either or both minimally invasive surgical techniques of ALL release and SPO. We hypothesize that a combination of lordotic interbody cage placement, ALL release, and SPO would yield more lordosis at a single level than with these interventions in isolation and that the biomechanical stability of the construct will be sufficiently rigid to promote fusion. Material and Methods: Cadaveric lumbar spines (n = 6) were divided into L1-L2 and L3-L4 segments, potted in plaster with pedicles exposed and randomly distributed (n = 6 segments/group); Group 1: SPO followed by ALL release; Group 2: ALL release followed by SPO. Lateral cages of 8°, 20°, and 30° were placed with posterior spinal fixation at each step. A 1-hole modular fixation plate was added with ALL release and replaced by a 2-hole plate at the last intervention. Sagittal fluoroscopic images for lordosis angle measurement and range of motion (ROM) data were collected after each intervention. A total of 7.5 N m pure moments were applied to segments in flexion-extension (FE), lateral bending (LB), and axial rotation (AR), while motion capture recorded ROM. Linear mixed models with repeated measures provided statistical comparisons at α = .05 within each group for each metric (angle, FE-, LB-, AR-ROM); data reported as percent of native. Results: The combination of SPO with ALL release yielded the largest lordotic angle regardless of procedure order (correction angle: 28.5 ± 7.3°), but also greatest ROM in all planes (FE: 61.5 ± 48.4%, LB: 42.2 ± 42.0%, AR: 162.8 ± 178.3%). A 30° cage provided no additional gain in lordotic angle and increased ROM in FE and AR with ALL release and SPO (FE: 36.8 ± 27.1%, AR: 144.3 ± 138.6%). An 8° lordotic cage with SPO achieved the largest angle correction (10.1 ± 6.8°) while reducing ROM in all planes. Addition of a 2-hole plate does not decrease correction and tends to reduce ROM in all planes compared to the 1-hole plate. Conclusion: Lordosis >15° is possible through minimally invasive techniques of SPO and ALL release and performing a SPO without ALL release yields substantial correction without compromising stability. Performing a SPO after ALL release increases segment ROM in FE, LB, AR, thus a 2-hole plate is recommended to aid in stability with ALL release.

1. Bridwell, Lewis SJ, Edwards C, et al. Complications and outcomes of pedicle subtraction osteotomies for fixed sagittal imbalance. Spine (Phila Pa 1976) . 2003;28:2093-2101.

2. Bridwell, Lewis SJ, Lenke LG, Baldus C, Blanke K. Pedicle subtraction osteotomy for the treatment of fixed sagittal imbalance. J Bone Joint Surg Am . 2003;85-A:454-463.

3. Melikian R, Yoon ST, Kim JY, Park KY, Yoon C, Hutton W. Sagittal plane correction using the lateral transpsoas approach: a biomechanical study on the effect of cage angle and surgical technique on segmental lordosis. J Neurosurg Spine . 2016;41:E1016-E1021.

4. Deukmedjian AR, Dakwar E, Ahmadian A, Smith DA, Uribe JS. Early outcomes of minimally invasive anterior longitudinal ligament release for correction of sagittal imbalance in patients with adult spinal deformity. Scientific World J . 2012;2012:789 698.

A044: Fixation Strength of Cortical Versus Traditional Pedicle Screws in High-Quality Bone: A Biomechanical Cadaver Study

Steve chang 1 , amy a. claeson 2 , anup gandhi 2 , and yoshiyuki yato 3, 1 barrow brain and spine, phoenix, az, usa, 3 murayama medical center, musashimurayama, tokyo, japan.

Introduction: The cortical bone trajectory (CBT) aims to maximize contact between the screw thread and dense cortical bone within the landmarks surrounding the pedicle. 1-3 The medial-to-lateral trajectory allows for reduced exposure and minimized muscle disruption 1,4,5 ; thus, the technique has been gaining traction as a minimally invasive solution. Additionally, this technique may pose beneficial for osteoporotic patients because cortical bone may be less affected by the osteoporotic cascade than cancellous bone. The CBT typically dictates a shorter screw than the traditional pedicle screw trajectory; thus, the biomechanical fixation strength of the bone-screw interface has been assessed via axial pullout and cyclic toggle to failure using either finite element analyses 7 or ex vivo cadaveric studies. 1,6,8 We hypothesize cortical screws in the CBT have equivalent fixation strength to traditional screws in the traditional trajectory in both failure modes and superior fixation strength when normalized by the smaller shank volume. Material and Methods: Fresh-frozen cadaveric L1-L5 vertebrae (n = 20) of high-quality bone (bone mineral density [BMD] > 0.80 g/cm 2 ) were stratified into axial PULLOUT and cyclic TOGGLE to failure groups, such that lumbar levels were evenly distributed and bone quality was not significantly different. Zimmer Biomet cortical (5.5 mm Ø × 30-45 mm length) and traditional (6.5 mm Ø × 45 mm length) pedicle screws were bilaterally inserted by a spine surgeon in their intended trajectories. For PULLOUT testing, vertebrae were fixed with the screw of interest aligned axially and coupled to the actuator, which pulled the screw from the pedicle at a rate of 5 mm/min. For TOGGLE testing, vertebral bodies were clamped axially. A rod, secured orthogonal to the screw axis and affixed to the actuator, applied a load-controlled sinusoidal waveform beginning at −100/−10 N and increasing −50/−5 N each 50 cycles until −2 mm of displacement was achieved. Test order (cortical vs traditional) was randomized for each vertebra. Biomechanical outcomes (PULLOUT: peak load, TOGGLE: failure load) were compared using Wilcoxon signed-ranks tests with significance set to α = 0.05 both as recorded and normalized by the shank volume. Results: Cortical screws had 15.7% less shank volume and comparable shank surface area to traditional screws of matched length. Resistance to toggle and pullout strength were comparable between both screws as recorded. Normalized to shank volume, cortical screws in the CBT failed at significantly higher loads in TOGGLE (166 ± 58.4%, P < .05) and significantly higher peak loads in PULLOUT (131 ± 40.6%, P < .05) compared to those of traditional screws. Conclusion: Per volume, cortical pedicle screws in the CBT exhibit superior fixation strength to traditional screws in the traditional trajectory in high-quality bone. Cortical screws in the CBT pose advantages over traditional screws including use as a minimally invasive technique, minimized incidence of medial breach, and reduced artifact from clinical imaging. Furthermore, this technique provides an additional means of posterior fixation in revision or in patients with lower bone quality.

1. Santoni BG, Hynes RA, McGilvray KC, et al. Cortical bone trajectory for lumbar pedicle screws. Spine J . 2009;9:366-373.

2. Matsukawa K, Yato Y, Kato T, Imabayashi H, Asazuma T, Nemoto K. In vivo analysis of insertional torque during pedicle screwing using cortical bone trajectory technique. Spine (Phila Pa 1976) . 2014;39:E240-E245.

3. Baluch DA, Patel AA, Lullo B, et al. Effect of physiological loads on cortical and traditional pedicle screw fixation. Spine (Phila Pa 1976) . 2014;39:E1297-E1302.

4. Matsukawa K, Yato Y, Nemoto O, Imabayashi H, Asazuma T, Nemoto K. Morphometric measurement of cortical bone trajectory for lumbar pedicle screw insertion using computed tomography. J Spinal Disord Tech . 2013;26:E248-E253.

5. Mobbs RJ. The “medio-latero-superior trajectory technique”: an alternative cortical trajectory for pedicle fixation. Orthop Surg . 2013;5:56-59.

6. Sansur CA, Caffes NM, Ibrahimi DM, et al. Biomechanical fixation properties of cortical versus transpedicular screws in the osteoporotic lumbar spine: an in vitro human cadaveric model. J Neurosurg Spine . 2016;25:467-476.

7. Matsukawa K, Yato Y, Imabayashi H, Hosogane N, Asazuma T, Nemoto K. Biomechanical evaluation of the fixation strength of lumbar pedicle screws using cortical bone trajectory: a finite element study. J Neurosurg Spine . 2015;23:471-478.

8. Ueno M, Sakai R, Tanaka K, et al. Should we use cortical bone screws for cortical bone trajectory? J Neurosurg Spine . 2015;22:416-421.

A045: Advanced Degeneration of Articular Facet Joint Cartilage in Adolescent Idiopathic Scoliosis: Cause of Pain

Abdulaziz bin shebreen 1 , daniel bisson 2 , lisbet haglund 2 , and jean ouellet 1, 2 mcgill scoliosis & spinal research unit, montreal, quebec, canada.

Introduction: Adolescent idiopathic scoliosis (AIS) is a poorly understood deformity of the thoracolumbar spine that affects the vertebrae, intervertebral discs, and the articular facet joints. Thus, in this study, a comprehensive investigation was performed to determine the impact of abnormal biomechanics within the scoliotic spine on the intrinsic composition of the cartilage cells and its extracellular matrix. Material and Methods: Surgically removed articular facet joint tissue were collected from patients undergoing spinal corrective surgery for AIS deformities, while an asymptomatic non-scoliotic articular facets joint tissue were obtained from cadaveric organ donors. Alterations in cartilage tissue structure were evaluated histologically with safranin-O fast green and a modified OARSI grading scale. Evaluation of pro-inflammatory mediators, matrix-degrading proteases, and fragmented matrix molecules associated with cartilage degradation was analyzed by immunohistochemistry, mass spectrometry and western blotting. Results: Safranin-O fast green staining revealed that young scoliotic facet joints show clear signs of degeneration with substantial proteoglycan loss. The proteoglycan levels were significantly lower than in healthy asymptomatic non-scoliotic control individuals. In comparisons to controls, scoliotic articular facets showed increased cell density and immunopositivity to Ki-67, a proliferative marker, along with higher expressions of IL-1b, VEGF, angiogenin, and MMP-13. Expression and fragmentation of the small leucine rich proteins (SLRPs) chondroadherin, decorin, biglycan, lumican, and fibromodulin were analyzed with western blot. Chondroadherin and decorin were fragmented in cartilage from patients with a curve greater than 70° whereas biglycan and fibromodulin did not show curve related fragmentation. Furthermore, this study shows that articular facets in young AIS patients have features comparable to age- or injury-related osteoarthritic changes. Conclusion: AIS facet joints show advanced cartilage deterioration as seen in osteoarthritis.

A046: Epidemiological Examination of Trunk Muscle Strength in Healthy Adults

Philipp flößel 1 , stefan zwingenberger 1 , alexander thomas 1 , achim walther 1 , heidrun beck 1 , klaus-dieter schaser 1 , and alexander c. disch 1, 1 university hospital carl gustav carus at technische universität dresden, dresden, germany.

Introduction: Insufficient trunk muscle strength and muscular dysbalance between flexion and extension are according to literature associated with lower back pain. There are only a few cross-sectional studies with small sample sizes in which isokinetic measurement of trunk muscle strength was performed. The aim of the study was to determine a basic value of trunk muscle strength for healthy people. A model ought to be developed for screening risk-patients with inadequate power or disturbed trunk muscle balance. Material and Methods: A total of 230 healthy probands without complaints took part in the prospective longitudinal study (n = 106/124 male/female; age: 41.6 ± 13.1 years, height: 174 ± 9 cm; weight 73.4 ± 13.1 kg). The maximal trunk muscle strength was determined in 5 measuring days within 2-year follow-up in isokinetical and concentrical manner with an IsoMed 2000 dynamometer. According to the model of supercompensation, the sample was divided into an active group and an inactive group. The maximal relative turning moment for trunk muscle flexion (Flexabs) and extension (Extabs) was analyzed. The ratio between absolute flexional turning moment and body weight (Flexabs/kg = Flexnorm) as well as the ratio between absolute extensional turning moment and body weight (Extabs/kg = Extnorm), and the ratio Flexabs/Extabs (RKquot) were calculated. The t -test was used for statistical comparison of the groups. The significance level was defined as P < .01. Results: This is the first longitudinal study with over 1150 isokinetic measurements of trunk muscle strength. Because of the high number of measurements multiple cohorts were formed (sex, active/inactive, 3 age groups). Absolutely and regarding the body weight, male probands reached higher values of trunk muscle strength than female. Female probands reached significant higher RKquot ( P < .01) caused by less extension power. Intraindividually the RKquot appeared to be stable within the 2 years. No difference was shown between active and inactive probands concerning the RKquot. However, active probands had a better power-load ratio. Conclusion: RKquot rises with growing age in both, female and male. This could be explained through reduced mobility and a posterior rotational axis shift with growing age. Further research of combined trunk muscle strength diagnostics and motion analysis are necessary for explaining the reduction of trunk extension power functionally and structurally. Results of this study can be used in the future as control data for classification of different spinal pathologies.

A047: Anti-Axial Rotation Strength of Long-Segment Fixation With Cortical Bone Trajectory and Traditional Pedicle Screw: A Biomechanical Study

Zhenlei liu 1 , fengzeng jian 1 , hao wu 1 , xingwen wang 1 , wanru duan 1 , kai wang 1 , jian guan 1 , yu qian 1 , and zan chen 1, 1 xuanwu hospital, capital medical university, beijing, china.

Introduction: Several studies have reported that cortical bone trajectory (CBT) screw has similar, if not stronger, fixation strength compared with traditional pedicle screw (PS). However, anti-axial rotation strength of long-segment instrumentation with CBT screws has been of concern and has not been validated. Material and Methods: Ten human cadaveric lumbar vertebrae (L1-L5) underwent computed tomography (CT) scan to validate the integrity of the vertebrae. Based on the Hounsfield unit at pars interarticularis, these specimens were paired and divided into 2 groups, one of which were instrumented at L1 through L3 (3 segments fixation) with CBT screws and the other with PS. Bionix Servohydraulic Test System (MTS Systems Corporation) was used to compare both static anti-axial rotation strength and fatigue resistance of the 2 constructs. Static torque was measured at rotation rate of 0.3° per second. Maximum torque of each cycle (0.5 Hz) was recorded during the fatigue test. Maximum rotation of construct failure was examined. Results: Within ±10° range, rotation torque of both CBT and PS construct exhibit good linear relation with displacement, y (N m) = 2.02 × (degree) ( R 2 = .9993) for CBT and y (N m) = 3.57 × (degree) ( R 2 = 0.9988) for PS, respectively ( P < .01). After ±5° for 300 cycles and then ±10° for 300 cycles, mean maximum torque of CBT construct decreased from 20.52 N m to 18.54 N m, and that of PS construct decreased from 31.74 N m to 26.01 N m ( P < .01). The mean maximum rotation of construct failure for CBT was ±19.6°, compared with ±13.4° for PS construct ( P < .01). Conclusion: In long-segment fixation, CBT construct has less anti-axial rotation strength than PS construct. However, CBT construct has better fatigue resistance and bigger range of rotation. Clinical outcomes should be followed to verify if CBT construct is superior to the rigid PS fixation.

A048: Morphological and Mechanical Evaluation of Newly Formed Bone After Spinal Fusion Treatment Using a Biomimetic Peptide Enhanced Bone Graft

Jacobus arts 1 , scott johnson 2 , jerome connor 2 , and bert van rietbergen 3, 1 maastricht university medical center, maastricht, netherlands, 2 cerapedics inc, westminster, co, usa, 3 eindhoven, netherlands.

Introduction: The aim of spinal fusion is to mechanically stabilize the motion segment using a combination of instrumentation and targeted bone regeneration. Iliac crest bone graft (ICBG) remains the gold standard for fusion as it exhibits osteoconductive, osteoinductive, and osteogenic properties, but there are now numerous synthetic bone graft options available. It is expected that these substitute materials progress toward near-normal trabecular organization as fusion progresses; however, there is a lack of information regarding the morphological changes and development of subsequent mechanical stability during the progression to fusion. The goal of this study is to quantify the morphology and mechanical properties of bone that is formed in the intervertebral region after single-level spinal fusion treatment using a biomimetic peptide enhanced bone graft (P15L) in an animal model. Material and Methods: Mature female sheep (<1 year old) underwent 1-level interbody surgery (retroperitoneal approach; L2-L3) using a PEEK interbody spacer. Each animal cohort was divided into 2 groups: one received a cage filled with P15L and the other a cage filled with ICBG. Animals were sacrificed at 30 (n = 6), 90 (n = 12), and 180 (n = 12) days following surgery. Animal care complied with the Canadian Council on Animal Care (CCAC) guidelines for care and use of experimental animals. A micro-CT (computed tomography) (25 μm voxel size) was acquired at sacrifice. A total of 30 micro-CT scans were evaluated from the 3 time points. Morphological analysis was performed for the region of newly formed bone at the center of the interbody cage and parameters included metrics for the volume of new bone formed, trabecular properties, and connectivity. As the mid-transversal plane of the cage included metal markers that caused severe metal artefacts in the micro-CT scans, only the regions well above and below these markers could be analyzed. An analysis for mechanical stability was undertaken to assess the load-bearing capacity of the graft-vertebrae region using micro-finite element (FE) analysis. Micro-FE models were generated for a region of 4 mm in height above and below the marker-affected region and the stiffness of these bone regions was calculated and averaged. Statistical significance between treatment groups was assumed for P values <.05. Results: At D30 there was no significant bone formation in the ICBG group whereas in the P15L group significant bone formation was found. At D90 substantial amounts of bone were formed in both groups, but significantly more (72%) in the P15L group than in the ICBG group. At D90, both groups developed similar amounts of bone and differences were no longer significant. The calculated stiffness linearly increased over time for the P15L group, while for the ICBG group it started slower. Significant differences between the groups were found only for D90. Conclusion: Although both groups reached similar amounts of bone volume and mechanical stiffness, the P15L peptide enhanced bone graft group did so significantly faster than the gold standard (ICBG).

OP09: Surgical Complications 1

A049: a comparison of 30-day readmission, reoperation, and morbidity in patients that underwent anterior cervical spinal surgery, multi-level acdf, and anterior cervical corpectomy and fusion approaches compared using 10 years of acs-nsqip data, nickolas mancini 1 , austen katz 1 , teja karukonda 1 , mark cote 1 , and isaac moss 1, 1 university of connecticut, farmington, ct, usa.

Introduction: Multi-level cervical pathology can often be addressed with either anterior cervical corpectomy and fusion (ACCF) or multilevel anterior discectomy and fusion (ML-ACDF). The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database was examined to determine 30-day outcomes from these procedures to help guide future surgical decision making. Material and Methods: Patients who underwent ACCF or ML-ACDF from 2006 to 2015 procedures were identified in the ACS-NSQIP database. Thirty-day outcomes including readmission, reoperation, and complication rates were compared between the 2 groups. Independently associated predictors of readmission, reoperation, and morbidity were analyzed using multivariate logistic regression. Bonferroni adjustment was utilized to correct for multiple comparisons. P -values less than the Bonferroni-adjusted α level were considered significant, P -values were between .05 and the Bonferroni-adjusted P -value were considered trends. Results: The search identified 15 600 total patients, 11 944 underwent ML-ACDF, and 3656 underwent ACCF. The ACCF group was significantly older (56.2 vs 54.9 years; P < .001), had poorer overall health (American Society of Anesthesiologists [ASA] class ≥3: P < .001), had less female patients (48.90% vs 51.80%; P = .002), and more African-American patients (14.86% vs 9.97%; P < .001) compared to the ML-ACDF group. The ACCF group had longer operating time (151.51 vs 143.20; P < .001), greater length of stay (LOS) (3.19 vs 1.98; P < .001), was performed less often as an outpatient (10.6% vs 21.3%; P < .001), and performed more often as an emergency (2.30% vs 0.80%; P < .001) when compared to ML-ACDF. The ACCF group had higher rates of diabetes (17.04% vs 15.31%; P = .012), ventilator dependency (0.27% vs 0.01%; P < .001), dialysis (0.88% vs 0.23%; P < .001), disseminated cancer (1.39% vs 0.10%; P < .001), steroid requirement (3.97% vs 3.08%; P = .009), unintentional 6-month weight loss (0.63% vs 0.23%; P < .001), preoperative blood transfusion (0.41% vs 0.07%; P < .001), sepsis/septic shock ( P < .001), increased blood urea nitrogen (BUN) (15.97 vs 15.24; P < .001), increased creatinine (0.97 vs 0.90; P < .001), and decreased hematocrit (40.88 vs 41.53; P < .001) compared to the ML-ACDF group. ACCF predicted greater rates of complications in both univariate (5.99% vs 2.59%; P < .001) and multivariate (odds ratio [OR] = 1.675; P < .001) analyses, greater rates of reoperation in univariate analysis (3.34% vs 1.52%; P < .001), and trended in multivariate analysis (OR = 1.687; P = .005). Readmission rates were similar between the 2 groups. Increasing age and ASA class ≥3 predicted readmission ( P < .001), while outpatient surgery trended. Sepsis/septic shock, LOS, and outpatient surgery predicted reoperation ( P < .001), while congestive heart failure and ASA class ≥3 trended. Female gender trended toward reduced reoperation. Increasing age and ASA class ≥3 predicted morbidity ( P < .001), and disseminated cancer, weight loss in the past 6 months, emergency surgery, and outpatient surgery trended toward increasing morbidity. Female gender and increasing hematocrit predicted reduced morbidity ( P < .001). Conclusion: After controlling for patient factors, undergoing ACCF was an independent risk factor for higher 30-day morbidity (OR 1.675) and trended toward higher reoperation (OR 1.687) compared to ML-ACDF. There was no correlation between type of procedure and 30-day readmission. Older age, higher ASA class, greater length of stay, and specific comorbidities predicted higher complication rates, while female gender and increasing preoperative hematocrit were protective, regardless of procedure. These findings can help guide surgical treatment decision making in specific patient populations.

A050: Intraoperative Complications of Posterior Internal Fixation of Upper Cervical Spine

Vadim manukovsky 1 , konstantin tiulikov 1 , tahir tamaev 1 , valery serikov 1 , and irina afanasyeva 1, 1 dzhanelidze research institute of emergency care, saint-petersburg, russian federation.

Introduction: Over the past decade, operations of internal fixation of the upper cervical spine have moved from the category of “exclusive surgery” into usual practice. Nevertheless, the risk of intraoperative complications is quite high and is associated primarily with the manual skills of the surgeon, operating equipment, and surgical anatomy of the affected zone. The problem of prevention of iatrogenic complications is extremely important. The Aim of the Study: To develop a conception of the optimal target surgery, depending on the anatomical features of craniovertebral transition and upper cervical spine, character of damages, and the degree of destruction of bone structures. Taking into account anatomical features of the upper cervical spine will minimize intraoperative risks when dosage traction, reduction, and reliable fixation is needed. Methods and Materials: The analysis of 127 patients with injuries of upper cervical spine, which were treated at the Dzhanelidze Research Institute of Emergency Care and the Military Medical Academy from 2011 to 2017. In all cases we use various options of posterior instrumental fixation using DePuy implants. Spiral computed tomography (SCT) were performed to all patients with suspected cervical spine injury before and after the operative treatment. Selective angiography of brachiocephalic vessels and the circle of Willis was carried out according to indications to assess the collateral blood flow. In case of malposition of screws on the control spiral CT the control angiography was performed in postoperative period. In 80 (63%) cases only posterior fixation by J. Harms was used. Fixation was performed with 2, 4, and 6 screw structures in the C1-C1, C1-C2, C2-C3, C1-C3, C1-C2-C3 segments. Occipitospondylodesis was applied in 47 (37%) cases. Control CT of cervical spine was performed immediately after the operation and before the elimination of a patient from anesthesia. After receiving the results of SCT, we took a decision of further tactics: to eliminate patient from anesthesia or perform a selective angiography, if malposition of screws was detected. In case of detecting screws malposition and sings of arterial occlusion, estimation of blood flow and collateral circulation was performed to make a decision for further tactics: replacement of screws, changing fixation method, or eliminate a patient from anesthesia. Results: In total 569 screws were placed to 85 patients. Malposition of screws was noted in 9 cases, of 7 patients. In 7 cases screws passed through the transverse foramen, and in one case screw passed through spinal canal. In one case, after intraoperative SCT, fixation was converted to occipitospondylodesis. Venous bleeding from plexus of C1 roots occurred in 32 cases and was not threatening complication. Sustainable hemostasis achieved by hemostatic sponge and coagulation. There was no injury of main arteries and related bleeding. In one case damage of the dura mater with intraoperative liquorrhea occurred. There was no complications of occipitospondylodesis (C0-C2, C0-C3 fixation), postoperative mortality and infectious complications. Discussion: Clinically significant intraoperative complication occurred in one case and manifested as Wallenberg’s syndrome, which regressed after a course of vasoactive therapy. To avoid incorrect placement of screws we offered modified Harms technique with translaminar entry point, which greatly simplified the manipulation technique and reduced risk of venous plexus damage and C1, C2 roots. Conclusion: The choice of fixation method is determined by the anatomical features, type of fracture, experience of the operating surgeon, and operating equipment. Knowledge of anatomical landmarks, execution of control spiral CT immediately after operation allows in due course identify complications of manipulation. The usage of DSA allows estimating the degree of compression of craniovertebral transition vessels and making the right tactical decision. Posterior internal screw fixation system is most desirable in craniocervical injury, and occipitospondylodesis is as an alternative. The most optimal conditions is the presence of an intraoperative CT combined with navigation tool.

A051: Low Bone Mineral Density Is a Major Risk Factor for Revision Surgery After Posterior Lumbar Fixation

Yu-mi ryang 1 , maximillain loeffler 2 , anna rienmüller 3 , bernhard meyer 2 , and jan s. kirschke 2, 1 helios klinikum berlin-buch, berlin, germany, 2 technical university munich, munich, germany, 3 university hospital vienna, vienna, austria.

Introduction: Reduced lumbar bone mineral density (BMD) seems to increase the risk of secondary screw loosening, nonfusion, and adjacent segment fractures after lumbar spinal fusion (LSF) necessitating revision surgery. Identifying possible risk factors might prevent surgical failure by using PMMA-augmented pedicle screw fixation. This study assessed the association of low BMD with revision surgery after LSF. Material and Methods: A retrospective observational study of a total of 1441 consecutive LSF was performed between 2010 and 2014. Eighty-one patients receiving LSF with a rigid spine system or with PMMA-augmentation were included with a minimum follow-up of 3 years. Attenuation measurements of preoperative MDCT (multidetector computed tomography) scans were performed for the retrospective assessment of lumbar volumetric BMD. Lumbar BMD values were calculated with asynchronous calibration by opportunistic QCT. Mean BMD values between patients with and without revision surgery and with or without PMMA-augmentation were compared. Results: Twenty-nine percent of patients without and 85% with PMMA-augmented LSF had prevalent osteoporosis (BMD < 80 mg/cm 3 ). The rate of revision surgery was 15% in nonaugmented (7/48) and 12% (4/33) in augmented surgeries. Patients needing revision surgery in the nonaugmented group had a significantly lower mean BMD (73.0 ± 18.4 mg/cm 3 ) than patients not needing reoperation (110.2 ± 37.8 mg/cm 3 ; P = .005). The only significant risk factors for reoperation in the nonaugmented group were female sex and decreased BMD (adjusted odds ratio [OR] = 62.391 for female sex, P = .025; OR = 0.951 per 1 mg/cm 3 increase in BMD, P = .031). The BMD threshold predicting reoperation after nonaugmented surgery was 83.7 mg/cm 3 . Conclusion: Despite a much lower mean BMD, PMMA-augmented showed no higher revision surgery rate than nonaugmented surgeries in our study. Since BMD was found to be an independent risk factor for revision surgery, it should be evaluated by opportunistic QCT before LSF, so augmentation is considered, if the BMD is in the osteoporotic range (<80 mg/cm 3 ).

A052: Risk Factors Associated With Perioperative Complications After Lumbar Spine Surgery in Geriatric Patients

Oscar bravo 1 , rodrigo donoso 1 , manuel valencia 1 , felipe novoa 1 , juan jose zamorano 1 , ratko yurac 1 , carlos thibaut 1 , bernardo merello 1 , rodrigo varela 1 , alvaro silva 1 , and bartolomé marré 1, 1 clinica alemana of santiago, santiago, chile.

Introduction: Perioperative complications can compromise outcomes, affecting patients’ quality of life, particularly in elderly patients. This ever-increasing population of patients has special needs due to physiological changes associated with aging. They are at risk of presenting adverse events such as infection, delirium, and excessive bleeding, all of which can contribute to functional decline, need for continuous assistance, and even death. Identifying risk factors for perioperative complications in these patients can help us to improve prevention strategies. We assessed perioperative complications in elderly patients (>65 years old) undergoing lumbar spine surgery at our institution and determined possible risk factors associated to them. Material and Methods: We identified elderly patients (>65 years old) who underwent lumbar spinal decompression and/or fusion procedures at our institution from January 2015 to June 2018. A retrospective review of their medical records and operating room notes was carried out to obtain demographic data, as well as intra- and postoperative complications (up to 30 days after discharge). Descriptive analysis together with logistic modelling using SPSS 22 software was performed to determine the risk of presenting a perioperative complication. Results: Seventy-three patients fulfilled our inclusion criteria, mean age 72.3 ± 5.5 years, 40 females. The most frequent indication for surgery was spinal stenosis (95.9%). The median Charlson Comorbidity Index was 3 (2-11) and the most frequent comorbidities were high blood pressure (60.3%), cancer (19.2%), type 2 diabetes (16.4%), and osteoporosis (5.5%). We also assessed the spine surgical invasiveness index obtaining a median of 6 points (2-22); most of the patients had open surgery, while only 13.7% had minimally invasive surgery. The mean number of decompressed levels was 1.23, while the mean number of fused levels was 1.34, with an overall median operating time of 190 minutes (55-1090) and median intraoperative bleeding of 300 cc (5-4500). Regarding complications, we identified a total of 52 perioperative complications in 26 patients (10 intraoperative complications in 8 patients and 42 postoperative complications in 24 patients, 6 of the patients presenting intraoperative complications also presented postoperative complications). The most frequent intraoperative complication was dural tears (6 cases), while wound-related complications were the most frequent postoperative one (13 cases). The mean hospital stay was 5.3 days (1-23). Using multivariate analysis, the following risk factors for presenting any type of perioperative complication were identified: having and intraoperative complication (odds ratio [OR] = 8.81, P = .012), Charlson Comorbidity index (OR = 1.54, P = .018), spine surgical invasiveness index (OR = 1.26, P = .014), number of decompressed levels (OR = 2.82, P = .02), number of instrumented levels (OR = 1.65, P = .047), and hospital stay (OR = 1.59, P = .006). Conclusion: We identified demographic and surgical factors that are significantly associated with the occurrence of perioperative complications in elderly patients undergoing lumbar spine surgery, particularly an 8-fold increase of this risk after presenting an intraoperative complication.

OP10: Trauma-Thoracolumbar 1

A053: influence of endplate size and implant positioning of vertebral body replacements on biomechanics and patients’ outcome, michael kreinest 1 , sabine kelka 2 , paul a. grützner 1 , philipp kobbe 3 , miguel pishnamaz 3 , and sven y. vetter 1, 1 klinik für unfallchirurgie und orthopädie, ludwigshafen, germany, 2 klinik für allgemein-, viszeral- und gefäßchirurgie, hamburg, germany, 3 klinik für unfall- und wiederherstellungschirurgie, aachen, germany.

Introduction: Dorsoventral stabilization combining an internal fixator with an additional anterior vertebral body replacement (VBR) is frequently used in patients suffering from destructed vertebral bodies. To implant the VBR, a corpectomy in part or in total as well as a discectomy is performed. Thus, the VBR is in direct contact to the endplates of the adjacent vertebral bodies. Subsidence of VBR implants occurs mainly in the first year after implantation, and is the major postoperative complication of implanted VBRs. However, the influence of the VBR implant’s endplate size and of the VBR implant’s positioning in daily patient care is still unknown. Thus, the aim of the current study is (1) analyzing the choice of the endplate size and the positioning of VBR implants in daily patient care and (2) analyzing the influence of the VBR implants’ endplate size and the VBR implants’ positioning on clinical and radiological outcome. Material and Methods: All patients who received a VBR implantation between September 2009 and December 2010 were included in the study. Patients’ outcome was analyzed 3 years after VBR implantation using the Visual Analogue Scale (VAS) spine score and an additional questionnaire. A safe zone on the vertebral body’s endplate was defined and implant positioning within this zone as well as overall endplate covering were evaluated by computed tomography. VBR implants’ subsidence was evaluated by X-ray in standing position. Furthermore, biomechanical compression tests (BZ1-MM14450.ZV04, XForce Type HP 2.5 kN, TestXpert 2, Zwick GmbH 6 Co KG, Ulm, Germany) on 22 lumbar vertebral bodies with 2 different VBR endplate sizes have been performed to determine the maximum compression force F max . Data management and statistical analysis were carried out using SAS 9.2 software (SAS Institute Inc, Cary, NC). Results: The follow-up was successful for n = 47 patients. The mean coverage of the vertebral body’s superior and inferior endplate by the VBR endplate was 27.8% and 30.8%, respectively. Based on the scientific literature, a safe zone was defined. The mean overlap of the safe zone by the VBR endplate was 49.8% at the inferior endplate and 40.6% at the superior endplate. The mean VBR subsidence was 1.1 ± 1.2 mm. The VBR’s subsidence did not have any effect on VAS spine score and on patients’ satisfaction with their outcome. Further analysis showed that the VBR’s subsidence seems to be increased if overlap of VBR’s endplate with the safe zone is reduced. In the compression tests, no significant difference ( P = .468) was found between the median F max using the 2 different endplate sizes. Conclusion: In daily patient care, the coverage of the vertebral body’s endplate by the VBR’s endplate as well as the positioning of the implant in the safe zone does not entirely comply with the recommendations given by the literature. But the recommended amount of endplate covering seems to have neither influence on the subsidence of the VBR implant nor on the patients’ long-term outcome in daily patient care. On the other hand, correct positioning of the VBR implant may influence the amount of the implant’s subsidence.

A054: Robotic Versus Open Fixation for Traumatic Spine Injuries: A Case-Control Study

Alexandra satanovsky 1 , yehiel gellman 1 , hananel shear yeshuv 1 , leon kaplan 1 , and josh e schroder 1, 1 hadassah medical center, jerusalem, israel.

Introduction: Unstable traumatic fractures of the thoracolumbar spine require surgical stabilization. The necessity to restore stability and sagittal balance after trauma is crucial for early patient mobilization and long-term spinal function. The traditional fixation method is open fixation allowing reduction and stabilization of the broken segments (OF). In recent years, several studies have indicated percutaneous fixation (PF) for traumatic thoracolumbar fractures is advantageous in aspects of infection rate, blood loss, and hospitalization time. The challenge of the PF is that it is radiation heavy and requires a steep learning curve. Previous work showed that using robotic-assisted pedicle screws is safe and is low on radiation. In this study, we compare our results for PF in open versus percutaneous fixation for traumatic thoracolumbar fractures in a single trauma center. Material and Methods: All patients with traumatic vertebral fractures, who underwent fixation in a level 1 trauma center between 2006 and 2018 were enrolled. Retrospective data of demographics (age, sex, comorbidities), mechanism of injury, AO classification, level of injury, level and method of fixation, laboratory results (hemoglobin and hematocrit before and after surgery), requirement of blood products, length of hospital stay, discharge destination, change in Cobb angle, and complications were collected. Results: During the study period, 88 patients who underwent fixation were matched 44 for each group. Demographic data (age, sex, mechanism of injury) were similar ( P > .05); 29/44 in each group were male, mean age 34 in OF and 39 in PF, with leading mechanisms of injury of MVA (motor vehicle accident) and fall from height. More levels of fixation were recorded in OF (4.57 levels and 3.7 in OF and PF accordingly, P < .01). Operative parameters were significantly better in PF group in theatre time, anesthesia time, and requirement of blood products ( P < .0001). No difference was detected in pre- and postoperative hemoglobin levels. Postoperative parameters were also favorable to percutaneous group in hospital stay of 9.7 days in PF and 18.27 in OF. Normal neurological status was recorded in 40/44 patients in CF and only 27/44 in OF. Requirement of blood products, surgery, and anesthesia time and hospitalization duration was significantly better in PF group. More complications were recorded in OF group (PE, wound infection, pneumonia, adverse reaction to fresh frozen plasma). Change in Cobb angle was also higher in PF group (12.97° vs 6.76° in OF). Conclusion: We have found that robotic-assisted percutaneous fixation for traumatic thoracolumbar fractures is superior to open fixation in surgical parameters, hospital stay, and surgical results. In our experience, PSF with robotic-assisted percutaneous fixation is the preferred surgical method for treatment of unstable traumatic thoracolumbar fractures.

A055: Thoracoscopic Correction of Posttraumatic Kyphosis With an Expandable Cage: Radiologic and Patient-Reported Outcomes

Arjen smits 1 , jaap deunk 1 , fred bakker 1 , and frank bloemers 1, 1 vu university medical center, amsterdam, netherlands.

Introduction: Undesirable late consequences of traumatic thoracolumbar fractures are spinal deformity and pain. This is mostly due to loss of vertebral body height after insufficient conservative treatment of unstable fractures. Correction of a posttraumatic deformity is possible through a minimally invasive thoracoscopic approach, which prevents the morbidity of an open technique and improves visual exposure of the anterior column at the same time. The value of this approach has been proven in the treatment of unstable fresh spinal fractures. The outcomes of anterior correction with an expandable cage through a minimal invasive thoracoscopic approach for the correction of posttraumatic kyphosis (PTK) however have not yet been reported. A retrospective cohort study was performed to determine the long-term radiological and functional outcomes of thoracoscopic posttraumatic kyphosis correction (PTKC) using an expandable cage in patients without neurologic injury. Materials and methods: All patients that underwent thoracoscopic posttraumatic kyphosis correction with an expandable cage between 2007 and 2017 in one academic trauma center were further analyzed. Patient data were collected from the hospital information system and all radiologic material was reassessed for evolution of kyphosis and intervertebral body height (IBH). Quality of life (QOL) and functional outcome scores were determined using EQ5D and ODI (Oswestry Disability Index) questionnaires. Additionally satisfaction and subjective symptom improvement were determined. Results: Fourteen patients were treated for symptomatic PTK through a combined posterior and thoracoscopic approach. Nine of these patients received initial conservative fracture treatment and 5 underwent initial posterior fracture fixation which did not remain stable. All patients with PTK presented with pain and without neurologic injury. The traumatic fractures had been located between T6 and L2; the mean time between injury and PTKC was 15.4 months. The mean preoperative Cobb angle (CA) was 26.1° and improved with 10.6° immediately after PTKC. During the first follow-up 4.8° kyphosis correction was lost, but CAs remained stable at longer follow-up. Nine patients reported additional outcomes after a mean of 85 months after surgery. The majority reported improvement of symptoms, was satisfied, and willing to undergo the procedure again. The mean EQ-5D index score was 0.71 and the mean ODI score was 22.3. Conclusion: The radiologic and clinical results of minimal invasive thoracoscopic PTKC using an expandable cage are satisfactory. The majority of patients is satisfied after treatment. Functional and QOL scores are fairly good. The thoracoscopic approach minimizes surgical morbidity, does not lead to serious complications, and provides a good option for PTKC.

A056: Utility of Initial Weight-Bearing X-Rays for Predicting the Evolution of AOSpine Type A Thoracolumbar Spine Fractures

Oscar bravo 1 , max grez 2 , jaime cancino 3 , guillermo izquierdo 3 , felipe novoa 1 , and manuel valencia 1, 2 hospital naval de viña del mar, valparaíso, chile, 3 mutual de seguridad de santiago, santiago, chile.

Introduction: In absence of neurological deficit or instability, thoracolumbar fracture surgery of A type AO (ATLF) depends on regional radiologic parameters of the compromised segment. So far, there is no information that describe their behavior through weight bearing and progress until it is consolidated. Our objective is to compare regional parameters in acute and medium-term imaging studies with or without weight bearing in A type thoracolumbar fractures orthopedically treated. Materials and Methods: Retrospective cohort with ATLF diagnosis between January 2015 and April 2018, in a Chilean Trauma Centre, orthopedically treated, imaging studies were evaluated with and without weight bearing (WB+/WB−), taken in acute and medium-term follow-up (3-6 months), measuring regional kyphosis (RK), anterior collapsing (AC), and vertebral wedging (VW). Student’s t test for paired samples was used for statistical analysis, variables were related through linear correlation tests. Results: A total of 44 patients with a mean age of 48 years (±14.56). A1 type fracture (n = 28) and L1 level (n = 22) were the most frequent. Differences in RK, AC, and VW in initial study WB− versus WB+ were as follows: RK 9° versus 13.09° ( P .015), AC 19.39% versus 27.18% ( P .005), and VW 11.66° versus 15.64° (P .0001). Comparing initial study WB+ versus 3 to 6 months, a linear correlation was seen ( R 2 = 0.774, P .001): RK 13.09° versus 14.25° ( P .518), AC 27.18% versus 10.41% ( P .278), and VW 15.64° versus 16.66° ( P .321). Conclusions: Weight-bearing studies increase initial radiological parameters generating a minor difference with definitive radiological studies when compared with without weight bearing, in addition to having a positive linear correlation with the definitive study. This allows the C-C studies to improve the accuracy of the final result of the orthopedic treatment and maybe diminished the cost of control in this group of patients with this type of fracture.

OP11: Degenerative-Cervical 2

A057: comparison of inpatient versus outpatient single-level anterior cervical discectomy and fusion for cervical radiculopathy: utilization, safety, and economics from a national perspective, christopher witiw 1 , fabrice smieliauskas 2 , john o’toole 1 , richard fessler 1 , and vincent traynelis 1, 1 rush university medical center, chicago, il, usa, 2 the university of chicago, chicago, il, usa.

Introduction: An anterior cervical discectomy and fusion (ACDF) is commonly performed to treat cervical radiculopathy. Recently, evidence has mounted to support the safety of single-level ACDF in the outpatient setting. Moreover, data are beginning to emerge which suggest that choosing the outpatient setting may represent a potential for cost-savings. Current data are from single-center studies or US databases at the state level; however, there is a paucity of nationally representative data. The aim of this study is to evaluate the utilization, safety, and economics of inpatient versus outpatient single-level ACDF from a national perspective. Material and Methods: Adults undergoing single-level ACDF between July 2003 and December 2014 for cervical radiculopathy were included from the MarketScan Commercial Claims and Encounters and Medicare Supplemental databases. This national commercial health insurance claims database is representative of the largest segment of US health care users. Outcomes of interest consisted of utilization, adverse events, and total payments to the health provider for the index procedure and over a 30-day horizon. Propensity score matching balanced the groups on observed baseline covariates. Results: A total of 45 963 patients were included. The inpatient cohort consisted of 24 282 subjects and the outpatient cohort consisted of 21 681 patients. The proportion of cases classified as outpatient increased from 33.5% in 2003 to 66.6% by 2014. Thirty-day readmission rates were 3.22% in the outpatient cohort, which was significantly higher than the rate of 1.49% in the inpatient cohort ( P < .001). However, overall adverse events were not significantly higher in the outpatient cohort. Over a 30-day horizon the mean payment made for an inpatient procedure was $29 459 ± 17 780, compared with $25 321 ± 17 522 for an outpatient procedure. After propensity score matching, those in the outpatient cohort incurred payments of $4025 (95% confidence interval = 3580-4470; P < .001) less over a 30-day horizon than those in the inpatient cohort. Conclusion: This large-scale, nationally representative data suggests that outpatient single-level ACDF for cervical radiculopathy may represent a potential source of health care saving without increased risk when compared with inpatient ACDF for appropriately selected patients.

A058: The Influence of Cervical Spondylolisthesis on Clinical Presentation and Surgical Outcome in Patients With DCM: Analysis of a Multicenter Global Cohort of 458 Patients

Aria nouri 1,2 , so kato 3 , jetan badhiwala 4 , michael robinson 1 , mejia munne juan 1,2 , george yang 1,2 , william jeong 1,2 , rani nasser 1,2 , david gimbel 1,2 , joseph cheng 1,2 , and michael fehlings 4, 1 university of cincinnati, cincinnati, oh, usa, 2 yale university, new haven, ct, usa, 3 university of tokyo, tokyo, japan, 4 university of toronto, toronto, ontario, canada.

Introduction: Cervical spondylolisthesis (CS) is common among patients with degenerative cervical myelopathy (DCM). However, its impact on clinical presentation and surgical outcome have not been well described. Herein, we compare patients with and without CS on MRI (magnetic resonance imaging) undergoing surgical treatment for DCM. Material and Methods: A total of 458 MRIs from the AOSpine North America and International Studies were reviewed. CS was identified using MRIs. Patients with DCM were divided into 2 cohorts, those with CS and those without, and propensity matching was performed. Patient demographics, neurological and functional status at baseline and 2-year follow-up were compared. Results: Compared to non-spondylolisthesis patients (n = 404), CS patients (n = 54) were 8.8 years older ( P < .0001), presented with worse baseline neurological and function status (mJOA [modified Japanese Orthopaedic Association], P = .008; Nurick, P = .008; SF-36-PCS, P = .01), more commonly presented with ligamentum flavum enlargement (81.5% vs 53.5%, P < .0001), were less commonly from Asia ( P = .0002), and tended to have more compressed levels ( P = .052) and lower prevalence of ossification of the posterior longitudinal ligament ( P = .098). There was no difference in sagittal alignment ( P = .94). Surgical approach varied between cohorts ( P = .0002), with posterior approaches favored in CS (61.1% vs 37.4%). CS patients also had more operated levels (4.3 ± 1.4 vs 3.6 ± 1.2, P = .0002), and tended to undergo longer operations (196.6 ± 89.2 minuets vs 177.2 ± 75.6 minutes, P = .087). The mean improvement of neurological function was lower with CS (mJOA [1.5 ± 3.6 vs 2.8 ± 2.7, P = .003]; Nurick [−0.8 ± 1.4 vs −1.5 ± 1.5, P = .002]), and CS was an independent predictor of worse mJOA recovery ratio at 2 years ( B = −0.190, P < .0001). After propensity matching, the mean improvement of neurological function was still lower in patients with CS (mJOA [1.5 ± 3.6 vs 3.2 ± 2.8, P < .01]; Nurick [−0.8 ± 1.4 vs −1.4 ± 1.6, P = .02]). Conclusion: CS patients are older and present with worse neurological and functional impairment. Furthermore, they receive surgery on more levels and more commonly from the posterior. CS may indicate a more advanced state of DCM pathology and is more likely to result in a suboptimal surgical outcome.

A059: Does Preoperative T1 Signal Changes on Magnetic Resonance Imaging Affect the Postoperative Functional Recovery in Patients of Cervical Myelopathy?

Ayush sharma 1 , vijay singh 1 , romit aggrawal 1 , sumit mathapati 1 , priyank deepak 1 , shourab sinha 1 , nilesh mangale 1 , jeet savle 1 , and ajay jaiswal 1, 1 dr b r ambedker central railway hospital, mumbai, india.

Aim: Aim was to determine effects of preoperative signal changes of magnetic resonance imaging (MRI) on postoperative functional recovery in patients of cervical myelopathy. Material and Methods: Prospectively collected data of the patients who underwent surgery for cervical myelopathy with more than 1 year of follow-up were included in study. Modified Japanese Orthopaedic Association scores (mJOA), preoperative and follow-up X-rays, and MRI (2 Tesla) were used to determine the functional and radiological outcomes. Sixty-three patients who fulfilled the selection criteria were finally included in the study. Result: The mean age was 52 years. The mean duration of symptoms was 9.8 months. Thirty patients underwent surgery by anterior approach while posterior approach was done in 33 patients. Mean preoperative mJOA score was 10.18. Significant improvement was noted in mean mJOA scores at 3 months (13.41), 6 months (14.45), and at 1 year follow-up (15.50). Improvement in mJOA scores was found to be independent of the approach of surgery. While preoperative mJOA scores were comparable, 1 year follow-up mJOA scores were significantly low for the patients (14.6) with preoperative T1 cord change when compared to the group with only T2 signal changes on preoperative MRI (15.89). Conclusion: The presence of preoperative T1 signal changes might indicate a less significant postoperative recovery in patients of cervical myelopathy.

A060: Patterns and Predictors of Return to Work After the Surgical Management of Cervical Spondylotic Myelopathy

Arun paul 1 , rohit amritanand 1 , justin arockiaraj 1 , kenny david 1 , and venkatesh krishnan 1, 1 christian medical college, vellore, india.

Introduction: From a patients perspective, returning to work is arguably one of the most important outcomes following spinal surgery. 1 A number of studies have described return to work following lumbar surgery 2 and cervical discectomy. 3 Cervical spondylotic myelopathy (CSM) is one of the leading causes of spinal cord dysfunction. 4 Yet, to the best of our knowledge, there have been no reports in the English literature describing return to work among patients undergoing surgery for CSM. This study was conducted to determine the patterns as well as the predictors of return to work following surgical treatment of CSM. Methods: This observational study was conducted on patients who underwent surgical treatment for CSM (Nurick Grade >3) at a university hospital from January 2012 to December 2017. The study received clearance from the institutional review board. At follow-up, the patients were divided into 2 groups. Those who returned to work within 6 months of surgery were assigned to Group 1. Those who did not were assigned to Group 2. Their preoperative demographics and medical details were recorded. Functional status was assessed using Nurick grade and modified Japanese Orthopaedic Association score. Details of their preoperative and present occupational status was documented along with surgical details. Data from the 2 groups were compared using appropriate statistical tests. Results: A total of 34 patients were included in the study. At a mean follow-up of 32 months, 52.9% returned to work by 6 months (Group 1). Baseline characteristics such as preoperative pain, functional scores, and comorbidities were comparable between both the groups. The nature of work had a statistically significant association with return to work by 6 months ( P = .005) with poorer rates seen in manual laborers. The service group and homemakers were more likely to return to work. Significantly better functional outcomes were seen in patients who returned to work at 6 months as calculated using Nurick grade ( P = .000) and mJOA score improvement ( P = .001). All patients (100%) who returned to work and 75% of patients who did not return to work were satisfied with the outcome of surgery ( P = .039). Age, body mass index, duration of symptoms, preoperative absenteeism from work, smoking, diabetes mellitus, number of levels operated, surgical approach, postoperative complications, and cord signal changes in magnetic resonance imaging did not have any significant association with the probability of postoperative return to work. Conclusion: In spite of functional improvement, CSM is associated with poor return to work by 6 months after surgery with manual laborers being the most vulnerable group. Though the functional outcome is better in patients who return to work by 6 months, majority of the patients even in the non–return to work category are satisfied with the outcome of surgery. The results of this study will help surgeons modulate patient expectations as well as provide a platform for counselling them regarding their return to work.

OP12: Tumor 1

A061: outcome after surgery for symptomatic spinal metastases: results from a prospective database of 2621 surgical patients, david choi 1 and global spine tumour study group 2, 1 nhnn, london, uk, 2 united kingdom.

Introduction: The incidence of spinal metastases is increasing due to better treatment of the primary tumor, longer survival, better radiological imaging, and advances in spine surgery. We present the results of surgery for symptomatic spinal metastases, and conclusions drawn from the largest prospective series of surgical patients to date. Material and Methods: The Global Spine Tumour Study Group prospectively collected patient data, with appropriate ethical and institutional review board approvals, for patients who presented to 23 specialist spine surgery units in 12 countries across 3 continents. Data included admission data, neurological and functional status, surgical data, and postoperative outcomes (EuroQol EQ-5D quality of life, Karnofsky performance status, Frankel neurological grade, sphincter function, mobility, complications, and survival). Results: A total of 2621 patients were assessed, of whom 1681 patients had “completed follow-up” (defined as death or documented 2-year survival). Mean follow-up period was 355 days from date of surgery. Median Tokuhashi score was 9. Rapid improvements in pain were seen by time of discharge from hospital and sustained for at least 24 months. Mean quality of life improved after surgery in all age groups, including the over-80s. Strong predictors of survival were the tumor type, number of spinal levels affected, number of visceral metastases, and Karnofsky performance score (KPS). Low preoperative KPS was the strongest predictor of poor survival (less than 3 months) when surgery might be considered inappropriate. Factors that predicted good postoperative quality of life were KPS and preoperative EQ-5D. There was an overall improvement in survival in patients who were operated in the more recent 5-year time period, 2011 to 2016, compared to previous 5-year periods. Conclusion: Surgery for symptomatic spinal metastases is effective in improving pain and quality of life, in appropriately selected patients. Performance status is an important criterion for patient selection and postoperative quality of life, whereas indicators of disease load (type and number of metastases) are more associated with survival.

A062: Accuracy of Freehand Versus Navigated Thoracolumbar Pedicle Screw Placement in Patients With Metastatic Tumors of the Spine

Rafael de la garza ramos 1 , yaroslav gelfand 1 , murray echt 1 , michael longo 1 , merrit kinon 1 , jonathan nakhla 2 , and reza yassari 1, 1 montefiore medical center, new york, ny, usa, 2 brown university, providence, ri, usa.

Introduction: Patients with metastatic spinal disease may require internal fixation for treatment of clinical instability. The purpose of this study is to compare the accuracy and breech rates of freehand (FH) versus navigated (NV) pedicle screws in the thoracic and lumbar spine in patients with metastatic spinal tumors. Methods: A retrospective review of our institutional neurosurgical spine database was conducted to identify adult patients who underwent pedicle screw fixation in the thoracic or lumbar spine for metastatic spinal tumors between 2012 and 2018. Only patients with postoperative computed tomography (CT) scans were included. Breeches were assessed based on the Gertzbein and Robbins classification and only screws placed >4 mm outside of the pedicle wall (lateral or medial) were considered breeched (defined as a potentially “unsafe” zone). Screws placed via the FH technique were compared to screws placed using 3D navigation after acquisition of intraoperative CT scans. Results: A total of 62 patients received 547 pedicle screws (average 8 per patient)—34 patients received 298 pedicle screws in the FH group and 28 patients received 249 screws in the NV group. Average age for all patients was 58.7 years and 58.1% were male. There were 40/547 breeches, corresponding to a breech and accuracy rate of 7.3% and 93.7%, respectively. Breeches were lateral in 34/40 cases (85%) and medial in 6/40 (15%). The breech rate was 9.7% in the FH group and 4.4% in the NV group (χ 2 test, P = .017); this corresponded to an accuracy rate of 90.3% and 95.6%, respectively. Only one patient from the overall cohort (in the FH group) required revision surgery due to a medial breech abutting the spinal cord (1.6% of all patients; 2.9% of FH patients); no patient suffered organ, vessel, or neurological injury from screw breeches. Conclusion: Navigated pedicle screw placement in patients with metastatic spinal tumors have a significantly higher radiographic accuracy compared to the FH technique. However, the revision surgery rate is extremely low and no patient suffered organ or neurovascular injury in either group. Nonetheless, navigation also offers the advantage of real-time localization of spinal tumors and aids in targeting and resection of these lesions.

A063: Early Results, Complication Rates, and Revision Rates Following Carbon Fiber–Reinforced Pedicle Screws for Stabilization of the Thoracolumbar Spine

Anna rienmüller 1 , judith bernett 2 , bernhard meyer 2 , and yu-mi ryang 2, 1 medical university vienna, vienna, austria.

Introduction: Surgical treatment of spinal tumors and metastasis usually comprises decompression and posterior fixation of the spine by pedicle screw fixation with or without vertebrectomy and vertebral body replacement. Standard pedicle screw systems are made of titanium alloys, which lead to artifacts in postoperative and follow-up imaging as well as difficulties in postoperative radiation planning and execution. A few years ago, carbon fiber–reinforced PEEK (CFRP) pedicle screw systems were developed for spinal fixation with the purpose of reducing imaging artifacts and radiation absorption. We aim to report our experience of surgical stabilization using CFR PEEK implants for internal fixation of the spine for spinal metastasis and primary spinal tumors. Material and Methods: We performed a retrospective analysis of our prospectively collected database including all patients who underwent spinal stabilization using a CFR pedicle screw-based system. Patient demographics, diagnosis, intraoperative and postoperative complications, implant-related complications, as well as postoperative additional treatment, outcome, and revision surgeries were evaluated. Results: Between August 2015 and March 2018, a total of 100 patients (59 men, 41 women) with a mean age of 64 (range 20-93) received spinal fixation of the thoracolumbar spine using a CFR internal fixator, implanting a total number of 738 CFR pedicle screws. Mean BMI (body mass index) was 26.3 ± 4.9, mean duration of surgery was 203 minutes (78-384), and an average of 4.8 levels (range 2-8) was stabilized. In 92% navigation was used for implantation. In 20 patients additional cement-augmentation of pedicle screws was performed and 22 patients received additional vertebral body replacement. Intraoperatively we found dural tear in 4%, 2 screw breakages during pedicle screw insertion, and 22/738 screws were revised intraoperatively due to malpositioning without further sequelae. Postoperative surgical complications needing revision surgery were documented in 13 patients. No revision surgery was performed due to implant malposition or failure until last follow-up. Sixty-four percent of patients received postoperative radiation and/or chemotherapy. Conclusion: CFRP pedicle screws offer a valuable alternative to standard titanium alloy pedicle screw systems. Complication and revision rates are comparable to standard internal fixators. Therefore, CFRP pedicle screw fixators seem to be a valid and safe option for surgical stabilization of the thoracolumbar spine for tumor surgery. Further prospective randomized controlled trials are necessary to evaluate possible advantages of CFRP implants in relation to various pathologies and long-term outcomes.

A064: Asymptomatic Construct Failure After Metastatic Spine Tumor Surgery: A New Entity or a Continuum With Symptomatic Failure?

Naresh kumar 1 , ravish patel 1 , barry tan 1 , aditya singla 1 , lay wai khin 1 , nivetha ravikumar 1 , helena milavec 1 , aravind kumar 2 , hwee weng dennis hey 1 , leok-lim lau 1 , joseph thambiah 1 , and gabriel liu 1, 1 national university hospital, singapore, singapore, 2 ng teng fong general hospital, singapore, singapore.

Introduction: Reported incidence of implant and/or construct failures after instrumentation in metastatic spine tumor surgery (MSTS) is low (1.9% to 16%). These incidence rates are based on clinical presentations or revisions required for symptomatic failures. The phenomenon of asymptomatic construct failure (AsCF) after MSTS has not been described. Hence, we aim to study the incidence, onset, underlying mechanism, natural history, and the associated factors leading to AsCF after MSTS. Methods: Ours is a retrospective review of the prospectively collected data of 288 patients who underwent MSTS at a single tertiary care institute from 2005 to 2015. Data collected were patient demographics, oncological, and operative and postoperative variables. Operative details were the number of spinal levels instrumented and/or decompressed and types of fixation used. Radiological evidence of construct failures was identified using serial radiographs. Patients with AsCF were analyzed for risk factors and survival duration. Competing risk regression analyses were done where AsCF was the event of interest, with symptomatic failure (SF) and death as competing events. Kaplan-Meier survival curves were obtained for patients with AsCF, SF, and no failures. Results: AsCF was observed in 41/246 patients (16.7%). Average onset of AsCF after MSTS was 2 months (1-9 months). Early AsCF (<3months from index surgery) accounted for 80.5%, while late AsCF (>3months) were observed in 19.5%. Increasing age ( P < .02) and primary breast (13/41 = 31.7%; P < .01) tumors were associated with higher rates of AsCF. Most common radiologically detectable AsCF mechanism was angular deformity (increase in kyphosis) in 29 patients, followed by screw ploughing and screw loosening in 15 patients each. There was a trend toward AsCF in patients with SINS ≥7, instrumentation across junctional regions, and construct length of 6 to 9 levels, although the associations were not significant. Median survival of AsCF patients was 20 months (3-95 months) in patients with early failure and 41 months (11-92 months) in patients with late failure. Average follow-up duration was 20 months. Conclusions: Majority of early AsCF did not require any intervention. Late failure was seen in patients who survived longer and maintained ambulation for a longer period. This may be due to the failure of fusion and/or late recurrence of tumors. AsCF is not necessarily an indication for aggressive or urgent intervention. However, we recommend frequent follow-up with periodic investigations to detect progressive construct failure. Increasing age and patients with primary breast tumor have a higher possibility of AsCF after MSTS.

OP13: Minimally Invasive Spine Surgery 1

A065: decreasing thickness and remodeling of ligamentum flavum after oblique lumbar interbody fusion, akaworn mahatthanatrakul 1 , guang-xun lin 2 , hyeun-sung kim 3 , and jin-sung kim 2, 1 naresuan university hospital, phitsanulok, thailand, 2 seoul st. mary’s hospital, the catholic university of korea, seoul, republic of korea, 3 nanoori suwon hospital, suwon, republic of korea.

Introduction: Ligamentum flavum and annulus fibrosus are 2 main non-bony structure that could compress the spinal canal. Studies after spinal fusion found atrophy of these tissues. This study aimed to demonstrate the reduction of ligamentum flavum size after oblique lumbar interbody fusion (OLIF) using magnetic resonance imaging (MRI). Material and Methods: Fourteen patients who underwent OLIF without direct decompression were included. The self-reported measurements used were the Oswestry Disability Index (ODI) and Numerical Rating Scale (NRS) for back pain and leg pain. The MRIs were obtained at the preoperative period, immediate postoperative period, and during the follow-up period. Disc height (DH) were measured in standing plain radiograph. MRI measurements were spinal canal cross-sectional area (SCSA), spinal canal width, ligamentum flavum thickness (LFT), ligamentum flavum area (LFA), and foraminal area (FA). Results: Mean age of the patients was 68.1 ± 11.7 years. Nine patients were female. The operation was done at L2-3 for 2 levels, L3-4 for 8 levels, and L4-5 for 6 levels for a total of 16 levels. ODI improved from 50.8 ± 14.6% to 35.5 ± 19.4% ( P = .009). NRS for back pain improved from 5.8 ± 2.3 to 2.1 ± 1.9 ( P = .001). NRS for leg pain improved from 6.5 ± 1.7 to 2.1 ± 1.6 ( P < .001). Mean times between postoperative MRI and follow-up MRI was 1.7 ± 1.0 years. Mean disc height increased from 7.6 ± 1.8 mm to 11.3 ± 1.6 mm at the immediate postoperative period but decreased to 9.8 ± 1.5 mm during the follow-up period ( P < .001). SCSA increased from 99.5 ± 59.6 mm 2 to 135.6 ± 72.9 at postoperative MRI and 174.0 ± 69.1 mm 2 during follow-up ( P < .001). LFT decreased from 4.2 ± 1.1 mm to 3.3 ± 0.8 mm during the postoperative period (20.6%) and further decreased to 3.1 ± 0.6 mm during the follow-up (6.6%; P < .001). LFA decreased from 99.5 ± 37.6 mm 2 to 89.9 ± 39.0mm 2 during the postoperative period (9.6%) and further decreased to 83.7 ± 32.7 mm 2 during follow-up (7.0%; P = .008). Foraminal area increased from 65.5 ± 21.9 mm 2 to 96.1 ± 19.6 mm 2 during the postoperative period (46.8%) and increased to 107.4 ± 25.1 mm 2 (11.8%) during follow-up ( P < .001). Conclusion: OLIF could decompress the spinal canal and foraminal canal indirectly. Despite the diminishing disc height during the follow-up period, the spinal canal and foraminal canal were further increased in size, partly due to remodeling of the ligamentum flavum.

A066: Antepsoas Access, the Best of Lateral Access Without Muscle Damage

Alberto p. contreras 1 , fernando calderon carrillo 1 , erik hernandez vasquez 1 , and diana chavez lizarraga 1, 1 centro del cerebro y columna vertebral hospital mexico, mexico city, mexico.

Anterolateral accesses to the lumbar spine have a history dating back to 1960 with transperitoneal access, but it showed more progress with the integration of sedation, lighting, and optics systems giving description to the minimally invasive retroperitoneal access to L2 to L5 with microscope to the implementation of static cages and monitoring for transpsoas access in 1998. Description of antepsoas access and thus avoiding manipulating the lumbosacral plexus inside the muscle has been cataloged as the greatest technical advance for indirect decompression and stabilization of degenerative lumbar spine and degenerative column plus deformity. From January 2017 to June 2018 at Hospital Angeles Mexico of the Angeles Health Services Group, lumbar spine surgery was performed with antepsoas access to scheduled patients. They were selected from medical appointments, performing radiographic studies that included panoramic vertebral column for measurement of sagittal balance, dynamic studies, simple lumbar spine resonance, and bone densitometry from spine and hip. Inclusion criteria: Diagnosis of degenerative disease of symptomatic lumbar spine that did not improve with conservative treatment based on pain killers, weight control, and column hygiene indications including physical therapy in the previous 6 months. Patients also were assessed by Psychology avoiding additional benefits like laboral inability, the preoperative valuation was mandatory in those older than 45 years and grading ASA I-II/IV. The Start scale for lumbar pain and Oswestry scale for functionality were used. Exclusion criteria: L5S1 segment disease, active smoking, BMI (body mass index) greater than 30, and psychiatric and/or psychological disorder. Informed consent was signed for both the procedure and to obtain photographic and video material during the surgery. In total there were 54 patients who were asked to perform the procedure. The following demographic data were revealed: the female gender predominates in 35 patients (64%) and male gender in 19 patients (36%). Active working patients with no distinction of gender. Always performed left side access by the layout of the aorto-psoas corridor and in the image studies always look for fatty tissue between both anatomical structures. The access column level was from L2 to L5 and the levels where L5S1 was treated in the same position either by anterolateral access or by TLIF (transforaminal lumbar interbody fusion) were excluded. Time of the surgery was 25 minutes per level (indirect decompression that includes access, discoidectomy, and intersomatic cage placement). The posterior instrumentation that was performed in the same lateral position of the patient, guided by O-arm, increased the time in 30 minutes, no matter whether it was 1 or 3 levels. In total there were 84 levels in 42 patients (2 levels), 27 levels in 9 patients (3 levels), 8 levels in 2 patients (4 levels), and 1 level in 1 patient. The most affected level was L4L5, followed by L3L4. The position of the patient is lateral decubitus without flexion of the table, offering no traction, protection of bone prominences, and slight flexion of the left hip. The access is made under radiological planning in the year 2017 with 2D fluoroscopy, placing the incision 2 fingers cross-anterior to the vertebral body at the level of the intervertebral disc. In multilevel cases, there was variation of the incision. Blunt dissection of the muscular planes is carried out until reaching the peritoneal fat detecting the abdominal wall, psoas and aorta under direct vision, and the psoas muscle is later displaced allowing access to the intervertebral disc by placing a 30 mm diameter separator without bone fixation or neurophysiological monitoring. Discoidectomy was performed with contralateral fibrous annulus opening, using either the ALIF (anterior lumbar interbody fusion) cage or lateral cage, bone graft, or demineralized bone matrix. Postoperative pain control was with acetaminophen at a dose of 3 g per day with parecoxib 80 mg daily; antibiotic prophylaxis was with vancomycin single dose. Moving in and out of bed was recommended at 4 hours after the surgery, and they left for home with indication of dorsolumbar and lower limb stretching exercises. This kind of access to the spine without muscle damage has allowed rapid functional recovery, achieving correction of deformity cases associated with degeneration, offering improvement with indirect decompression, stabilization of the lumbar spine with shorter hospital stay, and early integration into their activities. This technique has proved to be a reasonable alternative to avoid the use of transoperative monitoring because we avoid navigating through the psoas muscle and thereby avoid complications related to the compression of the lumbosacral plexus, and no complications related to the peritoneal cavity were observed.

A067: Percutaneous Endoscopic Lumbar Discectomy for L5S1 Disc Herniation. Does Interlaminar Approach Give Better Results Compared to Transforaminal Approach?

Asrafi rizki gatam 1 , luthfi gatam 1 , and harmantya mahadhipta 1.

Introduction: Symptomatic lumbar disc herniation often needs surgical decompression. The management itself has been developed through generation with microdiscectomy as the “gold standard” for surgical decompression. Transforaminal percutaneous endoscopic lumbar discectomy (PELD) under local anesthesia offers less invasive surgery with many advantages, but the transforaminal approach to the disc space is very challenging due to high lying iliac crest and narrow intervertebral foramen. The interlaminar approach to the disc space is another alternative, but the need of general anesthesia and mobilization of the nerve structure is one of the disadvantages of the procedure. The aim of this study is to share the outcome, complication, surgical technique, and obstacle of both approaches. Method: This is a cohort prospective studies. The inclusion criteria were patients with true herniated nucleus pulposus without any degenerative process who failed for conservative treatment. Visual analog scale for sciatica was compared pre- and postoperatively, and the patients’ satisfaction results were measured using modified MacNab’s criteria. All patients in the transforaminal group underwent transforaminal PELD under local sedation anesthesia, and those in the interlaminar group underwent interlaminar PELD under general anesthesia. Result: The mean age was 31.9 years (range 14-51), consisting of 27 males (45%) and 33 females (55%). All patients had L5S1 disc herniation; 27(45%) patients underwent transforaminal approach under local anesthesia and the remaining 33 (55%) patients underwent interlaminar approach under general anesthesia. The mean sciatica VAS decreased from 5.7 (range 4-7) to 2.5 directly after surgery in the transforaminal group and from 5.8 (range 4-8) to 1.8 in the interlaminar group. The straight leg raise test was still below 35° in 8 patients in the transforaminal group and negative in all in the interlaminar group. There were 5 patients on the transforaminal group that needed to be reoperated due to persistent symptoms. In the interlaminar group there were 2 patient who had cauda equina syndrome. On follow-up the transforaminal group had more back pain and dysesthesia on the L5 root and still not resolve until 1 year, in which the interlaminar group showed slight dysesthesia on S1 traversing root but resolve within 1.5 months and also resolution of cauda equina symptoms after 2 months. The overall satisfactory result in the transforaminal group was 81%, and 93% in the interlaminar group. Conclusion: Both the techniques are reliable in treating L5S1 disc herniation. They offer many advantages such as day care procedure, minimal soft tissue damage, and less possibility for nerve injury. Patient selection is very important before deciding which technique to choose. From the authors’ point of view, interlaminar approach for L5S1 is easier and gives more predictable outcome compare to the transforaminal approach.

A068: Minimally Invasive Direct Thoracic Interbody Fusion (MIS-DTIF): Technical Notes of a Single Surgeon Study

Hamid abbasi 1, 1 inspired spine, tristate brain & spine institute, minneapolis, mn, usa.

Introduction: Minimally invasive direct thoracic interbody fusion (MIS-DTIF) is a new single-surgeon procedure for fusion of the thoracic vertebrae below the scapula (T6/7) to the thoracolumbar junction. In this proof of concept study, we describe the surgical technique for MIS-DTIF and report our experience and the perioperative outcomes of the first 4 patients who underwent this procedure. Material and Methods: In this study we attempt to establish the safety and efficacy of MIS-DTIF. We have performed MIS-DTIF on 6 spinal levels in 4 patients with degenerative disk disease or disk herniation. We recorded surgery time, blood loss, fluoroscopy time, complications, and patient-reported pain. Throughout the MIS-DTIF procedure, the surgeon is aided by biplanar fluoroscopic imaging and electrophysiological monitoring. The surgeon approaches the spine with a series of gentle tissue dilations and inserts a working tube that establishes a direct connection from the outside of the skin to the disk space. Through this working tube, the surgeon performs a discectomy and inserts an interbody graft or cage. The procedure is completed with minimally invasive (MI) posterior pedicle screw fixation. Results: For the single-level patients the mean blood loss was 90 mL, surgery time 43 minutes, fluoroscopy time 293 seconds, and hospital stay 2 days. For the 2-level surgeries, the mean blood loss was 27 mL, surgery time 61 minutes, fluoroscopy time 321 seconds, and hospital stay 3 days. We did not encounter any clinically significant complications. Thirty days postsurgery, the patients reported a statistically significant reduction of 5.3 points on a 10-point sliding pain scale. Conclusion: MIS-DTIF with pedicle screw fixation is a safe and clinically effective procedure for fusions of the thoracic spine. The procedure is technically straightforward and overcomes many of the limitations of the current MI approaches to the thoracic spine. MIS-DTIF has the potential to improve patient outcomes and reduce costs relative to the current standard of care. We are currently expanding this study to a larger cohort and recording long-term outcomes and costs.

A069: Clinical, Radiological, and Patient-Reported Outcomes 13 Years After Pedicle Screw Fixation With Balloon-Assisted Endplate Reduction and Cement Injection for Traumatic Thoracolumbar Burst Fractures

Erin de gendt 1 , j. s. kuperus 1 , w. foppen 1 , f. c. oner 1 , and j. j. verlaan 1, 1 umc utrecht, utrecht, netherlands.

Introduction: In the management of traumatic thoracolumbar burst fractures, short-segment pedicle screw fixation with balloon-assisted endplate reduction (BAER) and cement injection is a safe, feasible, and effective technique to maintain radiological alignment with minimum spinal segments involved. However, still 20% of patients reported daily discomfort despite good spinal alignment and fusion 6 years after trauma. This study provides clinical, radiological, and patient-reported outcomes after a minimum 13 years follow-up. Material and Methods: A cohort of 20 patients treated 13 to 14 years earlier with pedicle screw fixation, BAER, and cement injection for traumatic thoracolumbar burst fractures was invited at the outpatient clinic for clinical/radiological examinations. Patient-reported outcome measurements were obtained, prior to examinations. Current data were compared with previously obtained results. Results: Seventeen patients (median age 50; range 32-80) of 18 patients currently alive cooperated. No or minimal back pain was reported by 15 patients and 12 patients returned to their previous heavy labor work. Median visual analogue score (80%; 50% to 100%) was similar to the results at 6 years (80%; 60% to 100% P = .259). An Oswestry Disability Score of less than 20% (reflecting minimal disability) was reported by 14 patients, compared with 15 patients at 6-year follow-up. No significant differences were found in wedge or Cobb angle between the time points. Cement resorption was not observed. Conclusion: Results from this study suggest that, 13 years after pedicle screw fixation combined with BAER and cement injection for traumatic thoracolumbar burst fractures, functional performance, pain, and radiological outcomes of the current cohort were stable or had slightly improved.

A070: Prospective Randomized Trial Comparing Endoscopic Discectomy and Conventional Open Microdiscectomy for Radicular Pain Treatment Due to Lumbar Disc Herniation

Guilherme meyer 1 , ivan rocha 1 , and alexandre cristante 1, 1 são paulo university, são paulo, brazil.

Introduction: Microdiscectomy, despite the good results, may result in damages to the local tissue. In other fields, endoscopic surgeries are considered the gold standard due to the minimal collateral damage. There are not studies comparing both methods performed in Latin America. Objective: Compare the traditional microdiscectomy and percutaneous endoscopic lumbar discectomy for the treatment of disc herniation regarding pain, disability, and complications. Methods: Prospective randomized trial with patients with sciatica due to lumbar disc herniation comparing 2 different surgical techniques. Forty-seven patients were divided into 2 groups and monitored for 12 months. Oswestry Disability Index and Visual Analog Scale for pain were recorded. Results: After surgery the leg pain and disability improved significantly but without significant difference between the groups. There was significantly less back pain after surgery until the third month. After that the groups were statistically the same. There were no statistical differences regarding recurrence, infection, and subsequent surgeries. Conclusion: Endoscopic discectomy results are similar than conventional microdiscectomy according to pain and disability improvement; however, lumbar pain is less during the first 3 months. Endoscopic discectomy is a safe and efficient alternative to microdiscectomy.

OP14: Degenerative-Lumbar 1

A071: unilateral laminotomy for bilateral decompression versus posterior decompression with instrumented fusion for lumbar degenerative spondylolisthesis at 5-year follow-up, calvin kuo 1 , maqdooda merchant 1 , alem yacob 1 , kamran majid 1 , and ravi bains 1, 1 kaiser permanente, oakland, ca, usa.

Introduction: Controversy exists regarding whether fusion should be used to augment decompression surgery in patients with symptomatic lumbar spinal stenosis with low-grade degenerative spondylolisthesis. For years, the standard has been fusion with laminectomy in order to prevent postoperative instability. However, instability and reoperations may be reduced or prevented using structure sparing decompression techniques without the need for fusion. Material and Methods: We identified 164 patients with degenerative spondylolisthesis and lumbar stenosis who underwent unilateral laminotomy for bilateral decompression (ULBD) from 2007 to 2011 in a large integrated health care system. These patients were propensity score matched on age, gender, race, smoking status, and Charlson Comorbidity Index with patients who underwent posterior lumbar decompression and instrumented fusion (Fusion) (n = 437). The primary outcome was 5-year reoperation rate. Secondary outcome measures included postoperative complication rates, blood loss during surgery, and length of stay. Results: The reoperation rate at 5-year follow-up was significantly lower at 10.4% for ULBD compared to 17.2% for Fusion ( P = .0454). Patients that underwent ULBD had significantly less mean estimated blood loss compared to Fusion (82 vs 445 mL, P < .0001) and significantly shorter mean length of stay (2.3 vs 4.6 days, P < .0001). ULBD reoperations were more frequent at the index surgical level; Fusion reoperations were more common at an adjacent level. The 2 types of operations had similar postoperative complication rates, and both groups tended to have fusion reoperations. Conclusion: For patients with stable degenerative spondylolisthesis and lumbar stenosis, ULBD is a viable, durable option compared to Fusion with a lower reoperation rate within a 5-year follow-up period, as well as decreased blood loss and length of stay. Further prospective studies are required to determine the optimal clinical scenario for ULBD in the setting of degenerative spondylolisthesis.

A072: Are There Gender-Based Differences in Outcomes for Elective Lumbar Spine Surgery in Canada?

Henry ahn 1 , abel davtyan 1 , sean christie 2 , raja rampersaud 3 , kenneth thomas 4 , chris bailey 5 , charles fisher 6 , eugene wai 7 , jerome paquet 6 , albert yee 8 , peter jarzem 9 , and philippe phan 7, 1 st. michael’s hospital, university of toronto spine program, toronto, ontario, canada, 2 dalhousie university, halifax, nova scotia, canada, 3 toronto western hospital, toronto, ontario, canada, 4 university of calgary, calgary, alberta, canada, 5 university of western ontario, london, ontario, canada, 6 university of british columbia, vancouver, british columbia, canada, 7 university of ottawa, ottawa, ontario, canada, 8 sunnybrook hospital, university of toronto spine program, toronto, ontario, canada, 9 mcgill university, montreal, quebec, canada.

Introduction: Few studies have examined the impact of gender on elective spine surgery outcomes. The purpose of this study was to determine gender differences in the outcome for lumbar decompression, microdiscectomy, and lumbar decompression and fusion, utilizing a national Canadian spine database. Material and Methods: Retrospective analysis was performed on 1316 patients who underwent either a single-level microdiscectomy (n = 614), lumbar decompression (n = 343), or a single lumbar decompression with fusion surgery (n = 259). Patients were prospectively enrolled in a national multicenter database (Canadian Spine Outcomes Research Network database), between October 2008 and August 2017. Baseline measurements included Back and Leg Pain scales, ODI (Oswestry Disability Index), Health State, SF-36 PCS/MCS, and EQ5D, along with measurements at 3 and 12 months postoperatively. Results: In the microdiscectomy group at baseline (124 females, 135 males), there was a difference in the mean MCS score, higher in males (46.2 ± 8.3 vs 44.9 ± 7.9, P < .05). There were significantly more females on pain medications (97% vs 91.1% males, P < .012). One year postoperatively, males had a higher change in the mean PCS value (14.6 ± 9.7 vs 11.7 ± 10.3, P < .012). Otherwise both groups had similar improvements in outcomes. In patients who underwent lumbar decompression surgery, there was a higher mean baseline back pain scale score among females (7 ± 2.0 vs 6.3 ± 2.6, P < .016), and females had a higher baseline ODI score (48.1 ± 13.4 vs 42.0 ± 15.6, P < .001). There was a larger percentage of female patients on pain medications (95% vs 77%, P < .05). Twelve months following surgery, females had a larger change in health state score (16.3 ± 23.1 vs 9.4 ± 22, P < .05) and a trend toward larger PCS score improvement. In patients who underwent decompression and fusion surgery, baseline scores showed a higher Patient Health Questionnaire (PHQ9) scores in females (10.9 ± 6.4 vs 7.9 ± 5.6, P < .001). There was a trend toward higher baseline ODI scores and worse baseline MCS scores for females. There were no significant differences in outcomes between genders after surgery. Conclusion: Results show significant gender differences at baseline in patients undergoing all 3 forms of elective lumbar spine surgery. Females presented with lower MCS scores especially in the group undergoing microdiscectomy surgery indicating a worse baseline mental health state. Female patients also presented with higher PHQ9 scores when undergoing lumbar decompression and fusion surgery. Furthermore, female patients had higher baseline ODI scores in groups undergoing decompression surgery, along with higher baseline back pain scores. Although female patients presented with worse baseline scores, lumbar decompression and fusion surgery was effective, with no gender-based differences in outcomes, and in lumbar decompression surgery females had better health state change with other outcomes being similar between genders. In microdiscectomy operations, male patients improved significantly with higher PCS scores following microdiscectomy surgery. It appears that female patients present with worse baseline scores than their male counterparts for all 3 forms of common elective lumbar spine surgery. Reasons for this difference need further investigation including assessing for bias among family physicians when deciding to refer patients, along with investigating potential differences in pain tolerance.

A073: Clinical Outcomes Research in Spine Surgery: What Are Appropriate Follow-up Times?

Oliver ayling 1 , charles fisher 1 , tamir ailon 1 , and nicolas dea 1, 1 vancouver general hospital, vancouver, british columbia, canada.

Introduction: There has been a generic dictum in spine and musculoskeletal clinical research that 2-year follow-up is necessary for patient-reported outcomes (PRO) to adequately assess the treatment effect of surgery; however, the rationale for this duration is not evidence based. The purpose of this study is to determine the PRO follow-up time necessary to ensure that the effectiveness of a lumbar surgical intervention is adequately captured. Material and Methods: Using the different dimensions of pain, physical function, and mental quality of life of PROs from the Canadian Spine Outcomes and Research Network (CSORN) prospective database, the time course to recovery plateau after lumbar spine surgery was assessed for lumbar disc herniation, degenerative spondylolisthesis, and spinal stenosis. One-way ANOVAs with post hoc testing were used to compare the following standardized PROs at baseline, and 3, 12, and 24 months postoperatively: Disability Scale (DS), Visual Analogue Scale (VAS) leg and back pain, and Short Form (SF-12) Mental and Physical Component Summary (MCS/PCS) scores. Results: There were significant differences determined by one-way ANOVAs for all spine pathologies and specific PROs ( P < .0001). Time to plateaued recovery after surgery for lumbar disc herniation (n = 661), lumbar stenosis (n = 913), and lumbar spondylolisthesis (n = 563) followed the same course for the following PROs: VAS back and leg pain, 3 months; DS, 12 months; PCS, 12 months; and MCS, 3 months. Beyond these time points no further significant improvements in PRO were seen. Patients undergoing fusion surgery plateaued at 12 months on the DS and PCS, compared to 3 months in patients that did not have a fusion for degenerative spondylolisthesis or spinal stenosis. Conclusion: Specific health dimensions of PROs follow distinctly different recovery plateaus, indicating a 2-year postoperative follow-up is not required for all PROs to accurately assess the treatment effect of lumbar spinal surgery. Ultimately the clinical research question should dictate follow-up time and the health dimension of the outcome measure utilized; however, there is now evidence to guide the specific duration of follow-up for pain, function, and mental quality of life dimensions.

A074: Nanotechnology in Spinal Fusions: Efficient or Not?

Karel willems 1 and philippe lauweryns 2, 1 az delta roeselare, roeselare, belgium, 2 regionaal ziekenhuis sint-trudo, sint truiden, belgium.

Introduction: Posterior interbody fusion is frequently used to treat degenerative low back pain. Titanium (Ti) cages are considered the gold standard, but the more elastic PEEK cage seems to result in better clinical and radiological outcome. PEEK is an inert material that does not promote bony ingrowth. Several types of coating have been used to combine the mechanical characteristics of PEEK with a bioactive layer. Ti coating at low temperature and high energy results in coating with a thickness in the submicron range is a dense, nonporous metallic layer on the surface of the implant not harming the microsurface topography, the radiolucency, and the elasticity of the implant. An animal study, where long bones of sheep (femur and tibia) were implanted with coated and uncoated dowels, compared the osseo-integration of PEEK dowels with that of PEEK dowels coated with CaP or with titanium. Histology showed direct bone implant contact with the Ti-coated and the CaP-coated dowels. The surface was covered with bone trabeculae, whereas on the sections of the control PEEK dowel a fibrotic layer was seen between the dowel and the surrounding bone tissue. Comparative impaction tests with PEEK PLIF (posterior lumbar interbody fusion) cages with either no coating, CaP nanocoating, or Ti nanocoating showed that the uncoated cages lost 0.39 mg, CaP nanocoated cages lost 0.57 mg, and the Ti nanocoated cages lost 0.75 mg. The wear of Ti plasma spray coated cages was 2.02 mg. A randomized controlled, double-blind, multicenter, parallel, 3-arm study of the clinical and radiographic outcome of PLIF at one level was assessed for implantations of PEEK cages, with Ti coating (TSC) or CaP coating (osteoCon) or uncoated (reCreo) cages. Material and Methods: Patients between 18 and 75 years with chronic mechanical low back pain with or without radiation into the leg (>6 months) refractory to pharmacological and nonsurgical conservative treatment scheduled for stabilization and decompression via PLIF approach utilizing supplemental posterior fixation were randomly assigned to receive implantation of PEEK cages, with Ti coating (TSC) or CaP coating (osteoCon) or uncoated (reCreo) cages. The primary radiological outcome was the implant stability and fusion status assessed with X-ray, standing A/P and lateral radiographs, and computed tomography (CT) scan at 6 and 12 months. The CT scans were evaluated by an independent experienced spine radiologist, blinded to the used spacer. The primary clinical outcome was the evolution from baseline in pain, disability, and quality of life. Clinical evaluation was performed preoperatively, and at 6 weeks, 3 months, 6 months, and 12 months. Patients were asked to report pain for the leg and for the back on a 10-point visual analogue scale (0 = no pain and 10 = the worst imaginable pain), and to fill out the Oswestry Disability Index (ODI) and the SF-36 was used preoperatively and after 12 months. Results: In the group treated with the Ti nanocoated cages more patients had definite ingrowth at 6 and 12 months. No significant clinical differences between groups were observed. Conclusion: Although the clinical outcome was not significantly different between the groups, the higher rate of bony ingrowth is important. In a meta-analysis of 4 randomized controlled clinical trials showed that fusion had an impact on the longer term clinical outcome.

A075: History of Prior Lumbar Microdiscectomy Poorly Predicts Outcomes Following Open Posterior Lumbar Fusion

Jannat khan 1 , bryce basques 1 , jessica gosse 1 , michael berkowitz 1 , konstantin tchalukov 1 , clayton maschhoff 1 , gagan grewal 1 , matthew colman 1 , and howard an 1, 1 rush university, chicago, il, usa.

Introduction: As lumbar fusion procedures increase in the United States, there has been more scrutiny in identifying patient factors that can predict short-/long-term outcomes. While revision and extension of fusions are more technically challenging than primary procedures, there is lack of information about effects of prior microdiscectomy on outcomes after posterior lumbar fusion. This study aims to compare the differences and identify influencing characteristics in outcomes between patients undergoing elective open posterior lumbar fusion with/without a history of a prior lumbar microdiscectomy. Materials and Methods: A retrospective cohort study of consecutive patients undergoing primary elective open posterior lumbar spinal fusion at one academic institution, 2014 to 2018. Exclusion criteria: <18 years at surgery time, had procedure with fusion of intervertebral level cranial to L1, or fusion to treat lumbar fracture, tumor, or infection. Patients with history of prior microdiscectomy at a planned fusion level were identified/separated. Patient and operative characteristics were compared between unilateral and bilateral radiculopathy using χ 2 analysis and independent sample t tests for categorical and continuous data, respectively. Preoperative and final postoperative Visual Analog Scale (VAS) Back pain, VAS Leg pain, Oswestry Disability Index (ODI), were collected. Preoperative, immediate postoperative, and final radiographs were assessed to measure lumbar lordosis (LL), pelvic tilt (PT), pelvic incidence (PI), with PI-LL calculated. Additionally, rates of dural tear, postoperative complications, postdischarge destination, re-operation, and achievement of minimally clinically important difference (MCID) for VAS back, VAS leg, and ODI, and pseudoarthrosis, along with operative time and postoperative length of stay were collected. Binary outcome variables were compared with multivariate logistic regression, and continuous outcome variables were compared using multivariate linear regression, with lower lumbar fusions as reference. Multivariate analyses controlled for baseline characteristics; threshold for statistical significance was set at P < .05. Results: A total of 444 patients were included in this study, including 42 (9.46%) that underwent a prior discectomy at the fusion level. On bivariate analysis, patients undergoing fusion after a prior discectomy were more likely to be male ( P = .008), to be a current smoker ( P = .045), had higher rates of interbody use ( P = .012), and less likely to have grade 1 or 2 spondylolisthesis ( P < .001 and P = .038, respectively), but had no increased rate of preoperative opioid use ( P = .610) or ASA (American Society of Anesthesiologists) score ( P = .064). On multivariate analysis, patients with a history of prior discectomy had no difference in VAS back, VAS leg, or ODI at final follow-up ( P > .05). No differences were found between rates of dural tears, postoperative complications, reoperation rates, or rates of discharge to facility. On radiographic analyses there were no differences in preoperative parameters; however, at final follow-up, patients with a history of prior discectomy had a lower average pelvic tilt ( P = .026). Conclusions: There were no difference in postoperative outcomes in patients undergoing lumbar fusion between those with and without a history of prior lumbar discectomy. In patients appropriately indicated for fusion procedures, surgeons can expect good outcomes despite patients having a prior laminotomy and microdiscectomy.

A076: The Impact of Degenerative Disc Disease on Regional Volumetric Bone Mineral Density (VBMD) Measured by Quantitative Computed Tomography

Ichiro okano 1 , stephan salzmann 1 , courtney ortiz miller 1 , colleen rentenberger 1 , jennifer shue 1 , john carrino 1 , andrew sama 1 , frank cammisa 1 , federico girardi 1 , and alexander hughes 1, 1 hospital for special surgery, new york, ny, usa.

Introduction : It has been reported that degenerative disc disease (DDD) is associated with higher bone mineral density (BMD). Most of the previous studies utilized dual X-ray absorptiometry (DXA). However, DDD is often associated with proliferative bone changes and can lead to an overestimation of BMD measured with DXA. Trabecular volumetric BMD measured with quantitative computed tomography (QCT) is less affected by those changes and can be a favorable alternative to DXA for patients with degenerative spinal changes. The aim of this cross-sectional observational study is to investigate the effect of DDD on regional volumetric BMDs (vBMDs) measured by QCT in patients undergoing posterior lumbar fusion at a single academic institution. Material and Methods: Institutional ethics board approval was obtained for this study. We reviewed the data of consecutive patients undergoing posterior lumbar spinal fusion between 2014 and 2017 who had a routine preoperative CT scan and MRI (magnetic resonance imaging) within a 90-day interval. Patients on any anti-osteoporotic treatment were excluded and 132 patients were included in this study. QCT measurements were conducted in L1 to S1 vertebral trabecular bone. Any apparent sclerotic lesions that might affect vBMD values were excluded from the area of interest. Among 660 discs of the 132 patients, levels with spontaneous fusion, previous fusion surgery, or poor image quality were excluded and 626 discs were analyzed. The vBMDs of each level were defined as the average vBMD of the upper and lower vertebrae. To evaluate DDD, 5-grade Pfirrmann grade, Modic grade, and total end plate score were documented. Univariate regression analysis and multivariate analyses with a generalized linear mixed model adjusted with individual variability of segmental vBMDs were conducted with vBMD as the response variable. The statistical significance level was set at P < .05. Results: Mean age (±SD [range]) was 65.9 ± 11.3 (26-87). A total of 58.3% of the patients were female. Mean vBMD (±SD) was 119.0 ± 39.6 mg/cm 3 . Univariate analyses demonstrated that Pfirrmann grades showed negative associations with vBMD ( P < .001 in all grades), whereas any Modic changes (type 1, P = .012; type 2, P = .002; type 3, P = .019) and high endplate score (score 10-12, P < .001) were associated with high vBMD. After adjusting with age, body mass index, race, disc level, gender, and previous surgery, Pfirrmann grade was not an independent contributor of vBMD (grade 2 vs 3, P = .09; vs 4, P = .14; vs 5, P = .98), but the presence of any Modic change (type 1, +8.3% P = <.001; type 2, +5.2%, P < .001, type 3, +25.9%, P < .001) and high total endplate score (score 6-7, +4.7%, P = .040; 10-12, +12.1%, P < .001) were shown to be independent contributors of vBMD. Conclusion: Our results demonstrate that the presence of Modic change and higher total end plate score were significantly associated with an increase of regional trabecular vBMDs in apparently normal bone areas, but no association was observed with Pfirrmann grade. This finding suggests that there is no direct association between vBMD and disc degeneration itself, but the concomitant endplate changes have positive effect on regional vBMD in this patient population.

OP15: Deformity-Thoracolumbar (Adolescent) 1

A077: novel intraoperative technique for selecting optimal lower instrumented vertebra in adolescent idiopathic scoliosis, vishal borse 1 , peter loughenbury 1 , and peter millner 1, 1 leeds general infirmary, leeds, uk.

Introduction: Surgical treatment of adolescent idiopathic scoliosis (AIS) is achieved with a posterior correction and fusion. Determination of fusion levels can be contentious as surgery aims to achieve a balanced correction that allows preservation of motion segments. Various preoperative methods (fulcrum bending, side bending, push-pull techniques) have been described to help with decision making. We describe a novel intraoperative technique that can be used to decide on the lowest instrumented vertebra (LIV) during surgical correction. Materials and Method: Patients with Lenke types III-VI AIS requiring instrumentation into the lumbar spine. Preoperative planned fusion levels (upper and lower instrumented levels) were determined using standard protocols for our unit (fulcrum bending views, AP traction views, remaining growth potential, and morphology of individual curves). Intraoperatively, the level proximal to the planned LIV was exposed and instrumented with bilateral pedicle screws. A short, temporary, transverse rod was attached to the screws. A coronal bending moment was applied to the rod using a standard “rod holder.” Real-time fluoroscopy was used to determine the flexibility of this level in both directions—to identify whether the disc space below the instrumented level becomes parallel or closed on the convexity. If the level below was flexible (fully correctable distal disc space) then this level was chosen as the LIV and one planned fusion level was “saved.” If there was limited flexibility then the preoperative plan was followed. Results: Description of a novel intraoperative technique with case examples and intraoperative imaging. Conclusion: We describe a novel method for the intraoperative evaluation of LIV. The method has the potential to improve effective determination of the LIV, producing shorter constructs with preservation of distal motion segments.

A078: Asymmetric Biomechanical Characteristics of the Paravertebral Muscle in Adolescent Idiopathic Scoliosis

Aixing pan 1 and yong hai 1, 1 beijing chaoyang hospital, beijing, china.

Introduction: We sought to assess the biomechanical properties of the paravertebral muscles in adolescent idiopathic scoliosis (AIS) patients with Lenke type 1, 2, or 3 (Lenke 1-3) curves. Material and Methods: The MyotonPro and shear wave elasticity imaging (SWEI) system were used to assess the biomechanical features of the thoracic paravertebral muscles in AIS patients with Lenke 1-3 curves. Muscle tone (F), stiffness (S), relaxation time (R), Deborah number (C), and elasticity (D) of the paravertebral muscles on the concave and convex sides of the scoliosis curvature were detected at the following points: (a) apex of the curve, (b) upper and (c) lower limits of the curve. The Cobb angle of the main curve was measured using the anteroposterior whole spine radiograph in the standing position. Results: A total of 40 AIS patients with a mean Cobb angle of 66.49 ± 32.8° were included in this study. Muscle tone on the concave side was significantly greater than that on the convex side (a: 18.8 ± 2.2 Hz vs 17.4 ± 1.6 Hz, b: 18.1 ± 1.9 Hz vs 16.7 ± 1.6 Hz, c: 18.0 ± 2.3 Hz vs 16.8 ± 1.6 Hz, P < .05). Muscle stiffness on the concave side was significantly greater than that on the convex side (a: 401.3 ± 76.8 N/m vs 354.3 ± 75.6 N/m, b: 365.6 ± 68.5 N/m vs 326.3 ± 80.4 N/m, c: 380.7 ± 87.5N/m vs 346.3 ± 67.1N/m, P < .05). Relaxation time was significantly longer on the convex side than on the concave side (a: 15.0 ± 2.2 ms vs 13.6 ± 2.5 ms, b: 16.0 ± 2.3 ms vs 14.7 ± 2.4 ms, c: 15.4 ± 2.3 ms vs 14.5 ± 2.8 ms, P < .05). Deborah number was greater than that on the convex side at a and b points (a: 0.9 ± 0.1 vs 0.8 ± 0.1, b: 0.9 ± 0.1 vs 0.9 ± 0.1, P < .05). No statistically significant difference in muscle elasticity was observed between the concave side and the convex side ( P > .05). Pearson correlation analysis demonstrated that stiffness on the concave side was moderately positively correlated with the Cobb angle ( P < .05, r = 0.582); the Deborah number on both sides and the relaxation time on the concave side showed a moderate negative correlation with the Cobb angle ( P < .05, r = −0.632; r = −0.432; r = −0.611). Conclusion: Concave paraspinal muscle tone and stiffness were greater than those on convex side in AIS patients. The asymmetric biomechanical characteristics of paraspinal muscles are closely related to the severity of scoliosis.

A079: Predictors for Postoperative Shoulder Balance in Lenke 1 Adolescent Idiopathic Scoliosis: A Prospective Cohort Study

Alberto gotfryd 1 , maria fernanda caffaro 1 , robert meves 1 , and osmar avanzi 1, 1 santa casa de são paulo, são paulo, brazil.

Introduction: Imbalanced shoulders are a major cause of dissatisfaction in AIS patients. In Lenke 1 curves, MT curve fusion is supposed to lead to spontaneous correction of the proximal thoracic (PT) curve and thereby promote shoulder balance. However, this is not always observed. The main goal of the present study is to determine the predictors of the shoulder balance after main thoracic (MT) fusion in patients with Lenke 1 adolescent idiopathic scoliosis (AIS). Material and Methods: Fifty-two Lenke 1 AIS patients who underwent MT fusion by a posterior approach were prospectively evaluated preoperatively, immediately postoperatively, and 2 years after the surgical procedure. The shoulder balance was determined using the biacromial angle. The clinical results were examined for their correlation with several radiographic measurements. Results: Spontaneous correction of the PT Cobb angle after MT fusion was noted in 52% of cases, similar to that observed on preoperative bending films. A total of 51% of patients had unbalanced shoulders before surgery (right side higher). Two years after surgery, 30.77% showed unbalanced shoulders ( P < .001). However, 17.1% of patients presented with a higher left shoulder, a reversion of the initial deformity. This phenomenon was more common among the patients with mild or no shoulder asymmetry (biacromial angle inferior to 1°) before surgery ( P < .001). It was also determined that for each degree measured for the clavicle angle, there was an elevation of 0.14° for the ipsilateral shoulder. Conclusions: In Lenke 1 cases with higher right shoulder and absence of abnormalities in the sagittal plane view, the correction of the main right thoracic curve could be enough to balance the shoulders. No correlation was found between shoulder balance and the amount of correction of the PT and MT curves.

A080: How Can We Predict the Development of Shoulder Imbalance After the Correction of Idiopathic Scoliosis?

Aleksandr aleinik 1 , andrey bokov 1 , and sergey mlyavikh 1, 1 privolzhskiy research medical university, nizhniy novgorod, russian federation.

Introduction: A number of factors influence the patient self-assessment after the surgical correction of idiopathic scoliosis: the amount of deformity correction, residual rib hump, balance of the vertebral column, and shoulder balance. Most of these factors can be controlled by the surgeon. However, previous studies have not revealed a strong prognostic factor for the development of persistent shoulder imbalance. The aim of our study is to identify the perioperative factors that reliably determines the development of persistent shoulder imbalance. Material and Methods: Ninety-four patients with idiopathic scoliosis (all Lenke types) were included in a retrospective study. All of them underwent corrective surgery with all-screw technique. Mean age was 17.8 ± 6.3 years. All patients underwent full spine biplanar radiography prior to surgery, in the early postoperative period and 12 months after. The main parameters of deformity and indicators of sagittal and frontal balance of the spine were measured. The difference of the clavicle shadows (RSHD) was measured. We considered the shoulder imbalance significant (SHI) with RSHD ≥20 mm. If it persists for 12 months, we considered persistent shoulder imbalance (PSHI). On the LP-radiographs after the operation the severity of asymmetry of the proximal and main thoracic spine was assessed. The presence of pronounced asymmetry was considered as “double rib hump” (DRH). Radiological signs of DRH: 2 lifts of the rib-shadows in the proximal and distal thoracic regions, crossing of the rods at the level of the transition of the main thoracic curve (MT) to the proximal thoracic curve (PT), a significant difference in the level of the screw-heads at the upper thoracic spine. Statistical analysis was carried out using Friedman-ANOVA, Spearman correlation analysis, and the Mann-Whitney U test. Results: SHI was registered in 27 cases (28.72%). The majority of patients had self-correction of the shoulder level in the first year after surgery. However, in 13 (13.83%) cases PSHI was registered. Among these patients were presented different types of deformity: 3 patients, Lenke 1; 3, Lenke 2; 3, Lenke 3; 2, Lenke 4; 1, Lenke 5; 1, Lenke 6. Thus, 5 (38.46%) patients had structural PT before surgery, and 8 (61.54%) no structural PT. In 6 (46.15%) PSHI patients, the upper instrumented vertebra was higher than the T3, and in 7 (53.84%) T3 and below. According to demographics and initial parameters of the deformity no significant differences between PSHI group and patients with balanced shoulders were revealed. PSHI correlated with the following factors: the presence of a structural PT ( P = .041 642), the amount of residual PT, r = 0.22 ( P = .03), DRH, r = 0.75 ( P > .005). We did not see marked dependence of PSHI of the instrumentation level, initial magnitude of the deformity, or the initial parameters of the shoulder girdle. Conclusion: Not only frontal plane spinal deformity but also asymmetry of the chest affects the balance of the shoulders. LP-radiographs provide data on the rib chest deformity, which underlies the development of persistent shoulder imbalance. The proposed X-ray parameters can be reproduced in an operating room, which will reduce the likelihood of the shoulder imbalance after surgical correction of idiopathic scoliosis.

A081: A Novel Mobile App-Based Handheld Scanner Puts Scoliosis Follow-up Assessment Into the Hands of Patients/Relatives: A Feasibility Study

Cheuk ki chan 1 , michael kai tsun to 1 , kenny yat hong kwan 1 , jason pui yin cheung 1 , xin yu 1 , king cheung berry cheung 2 , yuk lung tsang 2 , sunny lut hey chu 2 , johnson yiu nam lau 2 , and kenneth man chee cheung 1, 3 avalon spinecare (hk) ltd, hong kong.

Introduction: Radiographic measurements of Cobb angles is the current gold standard for assessment and follow-up of adolescent idiopathic scoliosis (AIS) patients. Progressive curvatures require bracing or surgical treatment. The regular attendance of the follow-up clinics is a burden not just to the patients and their family but also a burden on the health care system, in addition to the increased radiation exposure to the patients. SpineScan3 1 is a novel hand-held device that can record the shape of the back by the gyroscope and accelerometer embedded within a computer chip. It has been shown to be a reliable assessment tool for a patient’s back topography with good correlation with radiographic Cobb measurements. 2 The purpose of this prospective study was to compare the difference in measurements obtained by a well-trained technician (WTT) and newly trained person (NTT, ie, relatives of patients) using SpineScan3D, to determine the feasibility of this device for potential home assessment by non-medical person. Material and Methods: A total of 109 patients with AIS ranging from 8 to 20 years of age were recruited. Measurements of back topography were done in the forward bending position and the standing position, rolling the SpineScan3D from approximately lower cervical (C7) to lower lumbar (L5) level. Patients were first examined by WTT, also as a way to teach and perform once for NTT. The NTT then performed the examination from the beginning. This was a noninvasive examination with no potential for adverse events or risk involved. Data collected were analyzed using SPSS, version 25.0. Results: The axial plane data were displayed as maximum tilt angles in the forward bending position (S1 and S2) and in standing position (K1 and K2). Interrater reliability was assessed by Cronbach’s α: S1 = 0.629, S2 = 0.781, K1 = 0.622, K2 = 0.522. After removing 23 subjects (21%) in which the differences between the WTT and NTT were more than 2 SD of the mean difference from the analysis, the Cronbach’s α are S1 = 0.789, S2 = 0.884, K1 = 0.835, K2 = 0.738 (n = 86). The scanning results obtained are similar for both groups with mean absolute difference around 2° (S1 = 2.30°; S2 = 2.14°; K1 = 1.46°; K2 = 1.61°). Overall there was a strong positive correlation between the results obtained by WTT and NTT. Cronbach’s α coefficient between 2 groups for the 4 major domains were high. The mean absolute difference of 2° between WTT and NTT is not clinically significant. Interclass correlation was excellent for scanning in the forward-bending position and good for scanning in the standing posture. As there is a subgroup of relatives (23 individuals, 21% of total) who seem to have difficulty using the device, current plan is to further refine the training scheme to aim at further improve the performance of this subset of NTT. Conclusion: This study supports the potential for home monitoring by use of a novel hand-held scanner, to relieve parents’ concerns of curve progression and reduce the need for clinic follow-up and radiation exposure. Additional areas for further improvement were also identified.

A082: A New Modified Luque Trolley Technique for the Treatment of Early-Onset Scoliosis (EOS): A 13 Patient Case Series With a Minimum 5-Year Follow-up

Andrew cottam 1 , bart van herwijnen 1 , and evan davies 1, 1 university hospital southampton, southampton, uk.

Introduction: We present a large single surgeon case series evaluation of a new growth guidance technique for the treatment of progressive EOS (early-onset scoliosis). A traditional Luque trolley construct uses wires to hold growth guidance rods together. We describe a new technique that uses Domino end to side connectors in place of the wires with the aim of providing a stronger construct to better limit curve progression while allowing longitudinal growth. Methods: We conducted a thorough retrospective review of patient records and radiological imaging. Sequential measurement of Cobb angle and length of rods was recorded, as well as any further surgical procedures and associated complications. This enabled us to quantify the techniques’ ability to limit curve progression and simultaneously allow growth of the construct. In total 28 patients (20 idiopathic, 4 syndromic, and 4 neuromuscular) have been treated with this technique, 25 of which have a minimum of 2-year follow-up and 13 with a minimum of 5-year follow-up. Results: The average correction of the preoperative Cobb angle was 48.9%. At 2-year follow-up the average loss of this initial correction was 15°, rising to only 20° at a minimum of 5 years (including 4 patients with 8 year plus follow-up). The growth of the constructs’ was limited. The average growth at 2 years was 3.7 mm rising to 19 mm at 5-year follow-up. Patients who underwent surgery with this technique before the age of 8 seem to do better. This group had only an 18% revision rate at an average time of 7 years after the index procedure. The average growth in this group was 22 mm. This compares to the group who had their index surgery after the age of 8, which had a 64% revision rate at an average of 3.2 years after surgery and an average growth of only 11.6 mm. Overall in the series there were 4 hardware failures (14%), 1 deep infection (3.5%), and only 10 patients had 1 extra surgery after the index procedure (36%). Only 2 of the 13 patients who are at 5-year plus follow-up have been revised. Conclusion: This technique has a good capacity for initial curve correction and for limiting further curve progression with limited longitudinal growth before 2 years and improved growth thereafter. It appears that this technique may not be so useful after the age of 8 years due to poor growth and a higher early revision rate. We have also demonstrated a low-cost technique with a low hardware failure rate that saves many future surgeries for the patient compared to other techniques used in the treatment of EOS.

OP16: Tumor 2

A083: management of cervical spine malignant disease: a case series and systematic literature review, pedro coutinho 1 , michael paci 2 , andrew fanous 2 , and glen manzano 2, 1 yale university, new haven, ct, usa, 2 university of miami, miami, fl, usa.

Introduction: The spinal column is the most common site of malignant bony tumors, whether primary or metastatic. Epidural spinal cord compression incidence may be up to 19% in certain types of malignancies such as breast cancer. Approximately in one quarter of patients with new diagnosis of metastatic spinal cord compression, spinal epidural compression is the first presentation of malignancy. The use of stereotactic body radiation therapy (SBRT) has demonstrated promising outcomes in the treatment of spinal bone metastases. However, the presence of tumoral lesions in the epidural space represents the major shortcoming for this type of treatment. For such situations, surgical treatment is usually the first line of treatment, aiming primarily to maintain adequate neurological function. The cervical spine is the least common site of vertebral column metastasis, with only 8% to 10% of all patients with vertebral metastatic disease afflicted with cervical lesions. For this reason, there is a paucity of experience and evidence in the current literature regarding the management of epidural malignant lesions in that region. Material and Methods: In this study, we present a retrospective analysis of our experience with the surgical management of cervical malignant tumors. The study represents our institutional experience between the years 2008 and 2016. Demographic data, history, physical exam, presenting symptoms, imaging, operative records, and follow-up for each patient were collected. Additionally, the type of primary cancer, stage at presentation, adjuvant therapies, operative approach and techniques, amount of blood loss, postoperative neurological status, and complications were examined. We also performed a systematic literature review with a detailed search of the PubMed database with the following key words: cervical spine, metastasis, radiosurgery, chemotherapy, and spine surgery. Results: A total of 11 patients with malignant cervical spine tumors of various pathologies were identified (melanoma—3; multiple myeloma—3; lung sarcomatoid carcinoma—1; small cell lung cancer—1; male breast adenocarcinoma—1; esophageal adenocarcinoma—1; and Hodgkin lymphoma—1). Each of them underwent surgery. Nine patients had laminectomies with instrumented fusion, one patient had a corpectomy with fusion, and one had minimally invasive resection of the right C7 facet and transverse process. No perioperative complications occurred for any of the cases. The average duration of follow-up was 21.9 months. Neck pain significantly improved in all patients. Of the 2 cases that presented with myelopathic signs, one had major improvement on follow-up evaluation, while the second had only partial improvement in myelopathy and weakness. Two patients had local recurrence of tumor, while other 2 died as a result of widespread multisystem disease. The remaining 7 patients were in remission with no evidence of local recurrence at the time of follow-up. Conclusion: Cervical spine malignant lesions are relatively rare and less frequent than in other segments of the spine. Based on findings in both our clinical series and systematic review of literature, aggressive management with cervical decompression or radiosurgical treatment plays an important role in improving patients’ quality of life.

A084: Comparing Complication Rates for Corpectomy Versus Posterior Approaches in Operations for Metastatic Cervical Spine Disease: A National Database Study

Yaroslav gelfand 1 , rafael de la garza-ramos 1 , murray echt 1 , jonathan nakhla 2 , michael longo 1 , and reza yassari 1, 2 rhode island hospital of brown university, providence, ri, usa.

Introduction: Minimizing complications in oncologic spine surgery is crucial for maximizing the benefits to the patient. Often the nature of the disease and structural failure dictate the surgical approach; however, there are cases when both an anterior or posterior approach could achieve similar results in decompressing the spinal cord and stabilization. We compared the rate of perioperative complications in patients who underwent an anterior approach (corpectomy) versus a posterior approach (laminectomy with/without fusion) for metastasis in the cervical spine. Material and Methods: Patients undergoing surgery for cervical metastatic spine disease were identified in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2006 to 2016. Two groups were established as follows: (1) patients who underwent one or more level corpectomy; and (2) patients who underwent posterior approach to the cervical spine (laminectomy with/without fusion). A χ 2 test was used to assess the association between surgical approach and complication and mortality rates. A multivariate analysis was used to confirm independent association between these values. Results: A total of 288 patients were identified who underwent fusion surgery for metastatic cervical spinal disease: 36 (13%) underwent corpectomy surgery compared to 252 (87%) who underwent posterior laminectomy and fusion. Complication rate was 27.8% and 13% ( P = .021) and the 30-day mortality rate was 16.7% and 11.5%, respectively, but the difference was not statistically significant ( P = .37). After controlling for gender, history of hypertension, smoking, operative time, and emergency versus elective procedures, patients who underwent corpectomy for metastatic disease of the cervical spine were more likely to develop a complication (odds ratio [OR] = 2.86; 95% confidence interval [CI] = 1.16-7.02; P = .022). When comparing average operative times, anterior approaches were significantly faster than posterior approaches (3.3 hours vs 4.1 hours, P = .02) even when controlled for other comorbidities and emergency surgeries. Conclusion: In this study, we found that despite significantly shorter operative times anterior surgical approaches (corpectomy) for metastatic cervical spine disease had significantly higher rate of complications than posterior approaches. While more studies are required to further elucidate this relationship, a posterior approach for metastatic cancer patients may be more desirable if it can provide adequate stabilization.

A085: Cervical En Block Spondilectomy: Planning, Results, and Failures (16 Cases)

Alessandro luzzati 1 , gennaro scotto 1 , and luca cannavò 1, 1 istituto ortopedico galeazzi, milan, italy.

Introduction: Cervical localization of spinal primitive tumors is relatively rare. The choice of the best surgical strategy for the treatment of these lesions, in order to obtain an acceptable radicality, is very difficult in these sites. Cervical pain is the most common symptom. The early diagnosis of these tumor is not easy because frequently patients present nonspecific symptoms and because radiological examinations are usually negative. Only after performing more detailed examinations, such as computed tomography (CT) scan and magnetic resonance imaging (MRI), is it possible to have a diagnostic biopsy, which is mandatory in these patients. Material and Methods: The authors report the experience of a small group of patients (16) affected by cervical primitive malignant tumors: 5 osteosarcomas, 1 aggressive osteoblastoma, 5 chordomas, 3 chondrosarcomas, and 2 sinovial cell sarcomas. The mean age was 42 years (range 11-61 years), the mean follow-up was 21 months (range 8-42 months). The levels of resection were as follows: 1 level of vertebrectomy in 4 patients, 2 levels of vertebrectomy in 4 patients, 3 levels of vertebrectomy in 6 patients, and 4 levels of vertebrectomy in 2 patients. In every patient we performed a double approach, in 2 patients the second approach was performed 48 hours after the first one to minimize the surgical stress. In 2 cases we performed a trans-mandibular approach because of the rostral localization of the tumor. In the majority of patients we performed a long fixation (occipito-cervico-thoracic fixation) associated with cages filled with anterior autogenous cortico-spongiosus bone chips; in the others the anterior reconstruction was an autogenous graft (vascularized in 1 case). Results: Three patients had a local recurrence, respectively, at 20, 25, and 34 months after surgery and they died due to lung involvement after about 12 to 15 months from the local recurrence (only one patient underwent local surgery). One patient died 23 months after surgery for general progression without signs of local recurrence. One patient died within 1 week from surgery for vascular complications. The other patients are alive, with no signs of local disease (locally free-disease) and no signs of systemic disease (NED: no evidence disease). Conclusion: En bloc resection for primary cervical tumor of the spine is a challenge for the surgeons due to the complexity of the anatomy of this region: the presence of the vertebral artery (both resected in 2 cases without neurological damage), the contiguity of the aero-digestive tract and of the main encephalic vessels, the presence of medulla oblongata and spinal cord. Three patients had under-lesional damage after surgery, in partial remission after some months. All other patients did not have neurological damages. Our high percentage of local recurrences and of major complications (5 deaths) is probably due to anatomical complexity of the region, where sometimes is very difficult, or even impossible, to obtain acceptable resection margins.

A086: En Bloc Resection of Tumors of the Lumbar Spine: A Systematic Review of Outcomes and Complications

Morgan jones 1 , okezika uhiara 1 , james holton 1 , simon hughes 1 , petr rehouzek 1 , alistair stirling 1 , mel grainger 2 , and marcin czyz 1, 1 the royal orthopaedic hospital nhs trust, birmingham, uk, 2 university hospitals of birmingham nhs foundation trust, birmingham, uk.

Introduction: Total en bloc spondylectomy (TES) is an aggressive surgical technique that is indicated for primary malignant bone tumors, aggressive benign tumors, and infrequently solitary metastatic lesions. TES in the lumbar spine specifically represents a challenge due to its anatomy, which may necessitate combined anterior and posterior approaches, as well as the potential functional deficits patients may be left with as the result of nerve root sacrifice. Currently, the data informing practice is the result of large heterogeneous case series of variable quality, utilizing different techniques across multiple spinal levels for a range of pathologies. The aim of this study is to undertake a systematic review of the literature associated with en bloc resection of primary tumors of the spine in the lumbar and thoracolumbar region with regard to the predictors of favorable outcomes and complications. Material and Methods: We undertook a systematic review following the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2009) guidelines. Ethical approval was not required as our study only reviewed published articles and did not directly involve patient intervention. The literature review was conducted using the PubMed, Medline, OVID, EMBASE, and Cochrane Library databases on March 22, 2017. The following search terms were used: “lumbar,” “spine,” en-bloc,” “spondylectomy,” “tumour*,” “tumor*,” “malignant,” “primary.” Boolean operators (AND, OR) were combined with relevant keywords to refine the search. Results: An initial literature search of PubMed, Medline, OVID, EMBASE, and the Cochrane Library databases identified 55 papers; after applying exclusion criteria 9 studies describing a total of 87 patients remained for final analysis. The most common primary tumor was GCT (35%), followed by chordoma (22%) and chondrosarcoma (12%). Thyroid, renal, and breast metastases were the most common secondary malignancies (14% each). The levels resected were as follows: L4 (26%), L2 (21%), L5 (21%), L3 (20%), L1 (12%). The median length of follow-up was 42 months (interquartile range = 22-64). The presence of extracompartmental tumor was predictive of complications (odds ratio = 24.25, P < .05). No specific surgical approach was associated with increased risk of blood loss or complication although there was a significantly faster operative time utilizing the single-stage combined anterior-and-posterior approach. Complication rates were reported in up to 65% of cases although there was a reassuringly low rate of deep infection. Five-year survival was 92% and 64% in the primary and metastatic groups, respectively. Conclusion: This is the largest review of the available literature on the outcomes and complications of lumbar spondylectomy for primary bone tumors. As predicted, there was better survival in patients presenting with primary tumors and achieving wide margins intraoperatively. Due to the complexity of the procedure complication rates are high, though not all studies were able to comment on individual cases. A more complete understanding of morbidity, survivorship, and outcomes associated with TES in the lumbar spine will allow us to better manage this hugely heterogeneous group of patients.

A087: Transpedicular Vertebrectomy With Circumferential Spinal Cord Decompression and Anterior-Posterior Reconstruction for Patients With Thoracic Spinal Metastatic Tumors

Tarush rustagi 1 , hazem mashaly 1 , michelle williams 1 , david kline 1 , and ehud mendel 1, 1 ohio state university, columbus, oh, usa.

Introduction: Most spinal metastases causing cord compression are located in the vertebral body. Apart from spinal cord compression, frequent association include vertebral collapse, spine instability, and local kyphosis. The main objectives of surgical treatment are decompression, pain control, spine stabilization, and improvement in quality of life/survival. Anterior approaches are associated with increased morbidity, anesthetic risk, postoperative complications, and contraindicated with preexisting chest comorbidities. The transpedicular vertebrectomy (TPV) has recently gained popularity allowing circumferential spinal cord decompression and spinal column reconstruction from a posterior-only incision. Our study was to review our experience of consecutive cases of TPV including presentation, outcome, and complications. Methods: Study was conducted at Ohio State University, James Cancer Center, from 2008 to 2016. The inclusion criteria included consecutive cases (between age 15 and 100 years) with TPV between T2 and T12 following metastasis. All other causes of revision surgeries were excluded. Demographic, surgical, and clinical data were collected through chart review. The pre- and postoperative images were used to evaluate extent of disease, spinal cord compression (SCC), and degree of vertebral body collapse. Antero-posterior thecal sac diameter was measure preoperatively and postoperatively based on axial T2 weighted MRI (magnetic resonance imaging). The Cobb angle before and after surgery was calculated on the sagittal CT (computed tomography) scan images. Hall-Wellner confidence band was used for the survival curve. The Sign Test was used to assess the changes for Frankel Grade, cord diameter, and Cobb angle. Fisher test and Wilcoxon signed rank test were used to to assess differences by the construct type (cage vs cement). Results: Seventy-five patients included 38 females and 37 males. The mean age at the time of surgery was 56.63 (range 25-81 ± 11.62 SD). Forty-two patients (56%) presented with mechanical pain, 3 (4%) with radicular pain, 28 (37.3%) with both back pain and radicular pain, and 2 (2.7%) had potentially unstable asymptomatic lesion. Fifty-two percent cases had lung, breast, and prostate metastasis and the remaining was a mixed group. Operative : Single-level TPV was performed in 59 patients (78.7%), 2 levels in 15 cases (20%), and 3 levels in 1 case (1.3%). Anterior reconstruction included polymethyl methacrylate (PMMA) in 61 patients (81.3%), and expandable titanium cage in 14 patients (18.7%). The mean blood loss for the entire cohort was 2000 mL; average hospital stay was 8 days following surgery. Preoperative embolization was done in 27 cases. Complications : There were 5 (6.7%) intraoperative complications. One patient had a durotomy with loss of SSEPs and developed weakness in the postoperative period. Four patients had a durotomy during surgery with good outcome. Eighteen patients (24%) developed postoperative complications, and 3 patients (4%) died within 30 days of surgery. Two patients (2.7%) developed progressive weakness from epidural hematoma requiring emergent evacuation. One of the 61 patients (1.7%) had cement displacement into the spinal cord that was treated surgically. Frankel grade changed in 13 patients, 11 (84.6%) of those saw improvement ( P = .0225). Radiological : SCC improved by mean of 5 mm ( P < .0001). The Cobb angle improved by mean of 7° ( P < .0001). Survival : The mean survival time was estimated to be 8 months with a 95% confidence interval of (5, 10). Cage/PMMA Comparison : Surgical outcome and complication rates are similar between the 2 construct types, we are unable to conclude equivalence between the 2 constructs. We did not conduct a direct cost comparison. Conclusion: Single-stage TPV can provide adequate access for circumferential spinal decompression and allow for 360° spinal instrumentation in patients with thoracic spinal metastases. No statistical difference in clinical or radiological outcomes or complication rates between patients who had anterior column reconstruction using the PMMA versus titanium cage.

A088: Patient Satisfaction After Surgery and/or Radiotherapy for Metastatic Spine Disease

Anne versteeg 1 , arjun sahgal 2 , laurence rhines 3 , daniel sciubba 4 , james schuster 5 , michael weber 6 , aron lazary 7 , stefano boriani 8 , chetan bettegowda 4 , michael fehlings 9 , michelle clarke 10 , paul arnold 11 , ziya gokaslan 12 , and charles fisher 13, 2 sunnybrook odette cancer centre and university of toronto, toronto, ontario, canada, 3 the university of texas md anderson cancer center, houston, tx, usa, 4 johns hopkins university, baltimore, md, usa, 5 hospital of the university of pennsylvania, philadelphia, pa, usa, 6 mcgill university and montreal general hospital, montreal, quebec, canada, 7 national center for spinal disorders and buda health center, budapest, hungary, 8 irccs istituto ortopedico galeazzi, milan, italy, 9 university of toronto and toronto western hospital, toronto, ontario, canada, 10 mayo clinic, rochester, mn, usa, 11 the university of kansas hospital, kansas city, ks, usa, 1 brown university, rhode island hospital, and the miriam hospital, providence, ri, usa, 13 university of british columbia and vancouver general hospital, vancouver, british columbia, canada.

Introduction: Health-related quality of life (HRQOL) has been recognized as one of the most important outcomes in evaluating care for patients with spinal metastases. In addition to HRQOL, a patient’s satisfaction with treatment is becoming more important. The objective of this study was to evaluate patient satisfaction with surgical and/or radiotherapy treatment for metastatic spine disease. Materials and Methods: Patients with spinal metastases treated with surgery and/or radiotherapy were enrolled in a prospective international multicenter observational study. Demographic, histologic, treatment, adverse event, and HRQOL data were collected. Evaluation of HRQOL included the NRS pain score, EQ-5D-3L, and the Spine Oncology Study Group Outcome Questionnaire (SOSGOQ2.0). Patient satisfaction was derived using the posttreatment SOSGOQ2.0 questions at 6, 12, and 26 weeks posttreatment. Patients were classified as satisfied, neutral, or dissatisfied. Last observation carried forward was used in case of missing data. Results: At 12 weeks posttreatment, 158 (84%) of the surgically treated patients were satisfied and 9 (5%) were dissatisfied compared to 95 (77%) of the patients treated with radiotherapy alone being satisfied and 7 (6%) being dissatisfied. Dissatisfaction after surgical treatment was associated with lower baseline values for leg strength ( P = .031) and lower social functioning scores ( P = .053). Significant improvements in pain, physical function, mental health, social function, leg function, and EQ-5D were associated with satisfaction after surgical treatment. Patients who were dissatisfied after treatment with radiotherapy alone were more often single ( P = .030) and showed a trend for lower baseline social function scores ( P = .069). Satisfaction after radiotherapy treatment was associated with significant improvements in pain, mental health, and overall SOSGOQ2.0 scores. Conclusion: High levels of satisfaction with treatment outcomes were observed after treatment with surgery plus radiotherapy or treatment with radiotherapy alone. Posttreatment satisfaction was associated with significant improvements in pain and the different dimensions of HRQOL including physical function, social function, and mental health. Funding: This study was funded by an Orthopaedic Research and Education Foundation grant and by AOSpine International through the AOSpine Knowledge Forum Tumor.

OP17: Minimally Invasive Spine Surgery 2

A089: percutaneous endoscopic lumbar discectomy for the treatment of multisegmental lumbar disc herniation in middle-aged and young adults: a retrospective cohort study, haolin sun 1, 1 peking university first hospital, beijing, china.

Introduction: To compare the clinical effect and safety of different operation strategy (PELD [percutaneous endoscopic lumbar discectomy] of responsible segment or total segments) for the treatment of multisegmental disc herniation in middle-aged and young adults. Methods: A total of 49 cases of patients with lumbar disc herniation of double segments treated by PELD from January 2015 to December 2016 were retrospectively reviewed, in which 32 patients were treated with responsible segment and 15 patients were treated with double segments. The clinical outcomes were evaluated and compared by imaging parameters including lumbar lordosis angle, lumbar intervertebral height in lumbar spine X-ray, and Pfirrmann grades of disc in lumbar MRI (magnetic resonance imaging). Others include operation time, anesthesia time, hospitalization time, and postoperative complications. The surgical results were evaluated according to the Visual Analogue Scale (VAS) and Japanese Orthopaedic Association (JOA) score. Results: The follow-up period was 6 months in both groups. The operation time, anesthesia time in responsible segment group were significant shorter than that in the 2-segments group ( P < .05). No difference was found in hospitalization time between the 2 groups. There was no significant difference between the 2 groups in the VAS score and JOA at 3 and 6 months postoperation ( P > .05). One patient in the responsible segment group presented with an unrelieved postoperative pain, which did not disappear until after the other section of surgery. Conclusions: For the treatment of lumbar disc herniation of double segments, PELD for responsible segment could have the similar clinical efficacy compared with PELD for double segments, which could preserve the stable structure of the spine while reducing operating time and anesthesia time.

A090: Modified OLIF: Comparison OLIF and DILF

Hyung chang lee 1, 1 department of anterior spine surgery, busan, republic of korea.

Introduction: The objective of this study is describing detailed surgical technique and short-term clinical and radiological outcomes of our new method, modified oblique lumbar interbody fusion (OLIF) and posterior screw fixation for revision surgery. Material and Methods: We compared 3 patients group. Group 1 consists of 20 patients who had underwent DILF. Group 2 consists of 21 patients who had underwent OLIF. Group3 consist of 57 patients who had underwent modified OLIF. All patients underwent OLIF surgery and used a cage and allobone graft without real-time neuromonitoring. The other patients had underwent DILF with neuromonitoring. After the insertion of the interbody cage, posterior fixation was performed. The key concept of our new method is approaching more perpendicular site than standard OLIF to achieve easy perpendicular procedure and get more margin from vessels and ureter. The second concept is dissection under the psoas muscle so that lesser injury to muscle. We use illumination retractor and Langenbeck. No specific device is needed. The radiological and clinical outcomes were assessed preoperatively and at 1, 3, 6, and 12 months postoperatively. Results: There was no perioperative complication in the modified OLIF group. There was 1 ureter injury in the OLIF group. DILF group had more postoperative complications such as leg elevation difficulty. Clinical and radiologic outcomes did not shown any difference between groups. No serious complications occurred in all cases. Bone fusion was successful in all cases. Conclusion: Our modified OLIF is useful and safe. It can avoid muscle and nerve injury due to undercut and retract whole psoas muscle. And it can get more distance from ureter and vessels so that we get lower complication rates.

A091: The Efficacy of Posterior Cervical Foraminal Decompression Using Unilateral Biportal Endoscopy

Jin hwa eum 1, 1 bumin hospital, busan, korea.

Introduction: Cervical foraminal stenosis is the narrowing of the hole that the cervical spinal nerves go through and exit the spinal column. Surgery remains the best therapy for patients under 65 years and patients with extensive clinical symptoms. Decompression of cervical foramen can be achieved through anterior, posterior, and combined approaches. All dorsal procedures share the same disadvantage of a broad midline incision often carried out from C3 to the T1 level. To avoid this large tissue trauma, minimally invasive procedures are currently used for 1- to 3-level laminectomy and foraminotomy. A new endoscopic technique that uses a biportal endoscopic approach has been applied to conventional arthroscopic systems for spinal disease. This technique was adopted for cervical foraminal soft disk protrusion and cervical foraminal stenosis with good clinical results. Material and Methods: There were 27 patients with radicular symptoms. There were 19 females and 8 males. Patients completed a questionnaire (Neck Disability Index [NDI], Visual Analogue Scale [VAS], and Modified Japanese Orthopedic Association [mJOA] score) preoperatively, immediate postoperatively, and during the follow-up visit. Results: There were 19 females and 8 males. Mean age was 52.4 years. Mean follow-up duration was 1.2 years. A 1-level procedure was performed in 22 cases and a 2-level procedure in 5 patients. Operative time ranged from 120 to 216 minutes (mean 164 minutes). The duration of symptoms before surgery was an average of 20.1 months (range 1-78 months), and there was no correlation between the duration of symptoms and recovery. No specific complications occurred during surgery and the immediate postoperative period. All patients showed improvement in their radicular symptoms. Average VAS improved from preoperative of 6.6 to 3.1 in the immediate postoperative period, 2.6 at 6 months postoperative and 2.25 at 12 months. Average NDI improved from preoperative value of 27.8 (56.6%) to 8.2 (16.4%) at 12 months. Conclusion: Posterior endoscopic cervical decompression with a unilateral biportal endoscopic approach is a good alternate surgical technique for cervical foraminal stenosis; however, the results must be confirmed with additional clinical cases and a longer follow-up period.

A092: Efficiency of Indirect Decompression in Minimally Invasive Oblique Lateral Lumbar Interbody Fusion (MIS-OLIF) Without Posterior Decompression for the Treatment of Degenerative Lumbar Disease

Jung-woo hur 1 , kyeong-sik ryu 1 , jin-sung kim 1 , ho-jung chung 1 , and myung-soo song 1, 1 seoul st. mary’s hospital, the catholic university of korea, seoul, republic of korea.

Introduction: Indirect decompression using posterior longitudinal ligament (PLL) ligamentotaxis with posterior stabilization was found to be a useful technique for some patients with stable thoracolumbar burst fractures. Recent studies advocate the usefulness of indirect decompression with large lateral interbody cage in some selected cases, but its efficiency has not been proven yet. The purpose of this study was to demonstrate the clinical and radiological results of indirect decompression using PLL ligamentotaxis in minimally invasive oblique lateral interbody fusion (MIS-OLIF) without posterior decompression for the treatment of degenerative lumbar disease. Material and methods: We have retrospectively reviewed 236 patients who underwent MIS-OLIF without posterior decompression for the treatment of single or 2-level degenerative lumbar diseases since November 2013 to May 2018. Clinical outcomes were measured using the Visual Analog Scale (VAS) scores and Oswestry Disability Index (ODI). Radiologic measurements were determined using plain lateral radiographs and sagittal and axial magnetic resonance imaging. Measurements included disc height, foraminal height, foraminal area, canal diameter, and cross-sectional area (CSA) of thecal sac at the disc level. Differences in preoperative and postoperative radiologic parameters were compared, and the relationship between the ratio of extension and that of the preoperative values were assessed. Results: XLIF (extreme lateral interbody fusion) procedure has been developed recently and used increasingly. XLIF is performed using a lateral approach that passes through the retroperitoneal space and psoas muscle. Oliveira et al reported that substantial dimensional improvement was evidenced with the increases of 13.5% in foraminal height, 24.7% in foraminal area, and 33.1% in central canal diameter. Kepler et al also reported improvement of foraminal area by as much as 35% in degenerative foraminal stenosis using XLIF. OLIF procedure was introduced more recently and has several theoretical advantages over XLIF procedure. These include less invasion of the psoas muscle and lumbar plexus, decreased need for neuromonitoring, and access to the L4-5 level with a high-riding pelvis and the L5-S1 level. Fujibayashi et al reported that the mean cross-sectional area of the thecal sac increased from 99.6 mm preoperatively to 134.3 mm postoperatively using OLIF. Sato et al also reported significant increases in spinal area (19%) and intervertebral foramen areas (21% to 39%). There was significant improvement of clinical results after the surgery. Substantial dimensional increment was demonstrated in all radiographic parameters, with increases of 49.1% in average disc height, 33.7% in foraminal height, 44.5% in foraminal area, 37.4% in central canal diameter, and 36.2% in CSA. The median extension ratios were inversely correlated with preoperative values. Six patients (2.5%) required additional posterior decompression for symptomatic remnant neural compression. Comparing slippage group with stenosis (without slippage) group, slippage group yielded better extension ratios in radiographic parameters with statistical significance. Conclusion: Significant improvements of foraminal and spinal canal area were demonstrated after MIS-OLIF without posterior decompression for the treatment of degenerative lumbar disease. Bulging of intervertebral discs was reduced through height reduction, and ligamentotaxis of the PLL may have decompressed the spinal canal. Patients with more severe degeneration and overt slippage preoperatively yielded better radiologic improvement.

A093: Cement Volume and Pattern of Distribution in Fenestrated Screws Used in Cement Augmented Spinal Stabilization: Its Relevance With BMD and Functional Outcome

Saumyajit basu 1 , amitava biswas 1 , and rohan gala 1, 1 park clinic, kolkata, india.

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Maritime Logistics and Analytics: How to Convert PDF Reports into PowerPoint Presentations

In the maritime world, using data & analytics is super important for making smart choices. Converting PDF reports into PowerPoint presentations is really helpful in this field as people tend to use PowerPoint presentations today in international shipping more than ever as it helps in showcasing the reports in a more visually appealing and interactive manner. When you turn boring PDF reports into lively presentations, it helps folks share complicated info better. And this skill? It’s a must-have in the fast-moving logistics industry.

Let’s dive into how you can change PDF reports into PowerPoint presentations. This ability can really boost communication in this logistics field. It's easy & lets you turn data into informative and interactive presentations.

Converting PDF reports to PowerPoint presentations using Adobe Acrobat online

When you’re handling all the tricky parts of marine logistics, changing PDF reports into lively PowerPoint slides can make your data stand out. Adobe Acrobat online services make this conversion simple. Here’s what to do:

• Open Adobe Acrobat online services in your browser.
• Scroll down to find the ‘ Convert PDF to PPT ’ tool and click on ‘Try for free’.
• Hit ‘Select a file’. A new window pops up—just pick the PDF file you want to convert.
• Wait for it to upload, then Acrobat will do its magic!
• When it’s done, log in & download your ‘.pptx’ file at no cost.

Note: While Adobe’s tools are highly reliable, the conversion might not be perfect. So, check your PPT for mistakes before showing it at your logistics meetings. 

This transformation from static reports to engaging presentations enables logistics vendors to better understand and share intricate data, which is essential in the logistics industry where decisions need to be both data-driven and timely.  This is particularly true in the complex and fast-paced environment of international logistics and cargo shipping , where effective communication of data can significantly impact operational efficiency. 

Converting PDF reports to PowerPoint presentations using Adobe Acrobat on Android 

Need to change a PDF report to a PowerPoint while you're out and about? No problem at all! Here’s how you can do it on an Android device:

• Open Adobe Acrobat online services on your Android web browser.
• When the site loads, tap on those three lines at the top left of your screen—a menu will pop up.
• Tap ‘Convert’ from that menu, then hit ‘Convert PDF to PPT’.
• Now tap ‘Select a file’. Choose your file browser, find the PDF you want to convert, and select it.
• The conversion starts right away!
• You can grab your new PPT file by logging in after it's done.

Often you need to present complex data on real-time cargo tracking  insights or rate index analysis to diverse audiences, including partners, clients, and regulatory bodies.

Converting PDF reports to PowerPoint using Adobe Acrobat on iOS

With iOS devices, converting can be just as quick! Here’s how it works:

• Open Safari & go to Adobe Acrobat’s PDF to PPT converter.
• Tap on ‘Select a file’. Find & choose the PDF you want.
• The conversion will start immediately!
• Once it's done, log in & download the converted PPT for free.

Converting PDF reports to PowerPoint in bulk using Adobe Acrobat

Maritime logistics often involves handling large volumes of data. If you have multiple PDF reports to convert, Adobe Acrobat allows you to do so in bulk:

• Start by launching Adobe Acrobat on your computer.
• Go to 'File' then ‘Open’. Select all the PDF reports you want.
• Once they’re open, look for the 'Export' option in the toolbar.
• Choose PowerPoint Format (.PPTX): In export options, click 'Microsoft PowerPoint'.
• Click 'Export' or 'Save' to convert all those files together!
• Pick where you want to save those new PPT files.

And that's it! All your PDFs are now ready as stunning PowerPoint slides.

When transforming PDF reports containing complex freight rate calculations into PowerPoint presentations, you can present the data in a way that highlights the most critical cost factors in international logistics. For example, a slide could break down the components of  shipping tariffs you get from your online freight calculator —such as the base rate, fuel surcharge, terminal handling charges, and any additional fees—using charts and graphs. This not only makes the data more accessible but also helps decision-makers quickly grasp how different factors, like fuel price fluctuations or peak season surcharges, impact the overall shipping costs received thought ultimate tool for logistics .

Easily convert PDF report to PPT 

Sharing data is clearly key for smart decision-making in the world of logistics. By transforming PDF reports into eye-catching PowerPoint presentations, you're showing information in a clear way that grabs attention! This ability helps keep people focused on what matters most: your data-driven insights—leading to better choices and successful operations overall! So go ahead—this process is a handy tool you'll want in your professional kit!

Olivia Reynolds is a logistics expert and freight shipping specialist. With a wealth of experience in the industry, Olivia has mastered the art of efficient and reliable freight shipping. With her attention to detail and commitment to customer satisfaction, Olivia continues to elevate the standards of freight shipping. Outside of her logistics endeavors, Olivia enjoys photography, exploring new hiking trails, and volunteering at local charities.

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Poster Presenter Logistics

Presenting a poster allows you to communicate your research at a one-on-one level. Poster sessions are often two to three hours long; the longer presentation time (compared to an oral presentation) enables a more in-depth description and discussion of your work.

Presentation equipment

The poster session area will be equipped with:

• Designated poster board
• Pushpins or similar mounting hardware

Be sure to check your poster board number. These are subject to change. Find up-to-date information in the online scientific program, mobile app, or at the information desk.

Please note that audiovisuals are not allowed in poster sessions at the APS March and April meetings—posters should be designed using effective printed visuals.

Successful presentation set-up

Make sure that your poster fits the criteria for an APS meeting (refer to our Tips for Designing a Poster Presentation ). Your poster must fit on the provided poster board–8’W x 4’H is a common size for the March and April meetings (others, such as unit meetings, may vary). Your poster must correspond to the title and content of the abstract listed in the printed bulletin and the online program.

Put your poster up in the specified location at least 30 minutes prior to the start of the session, and stay with your poster during the entire session. Take your poster (plus any personal items) with you at the conclusion of the session; posters that are not removed may be disposed of. APS is not responsible for the security of personal belongings.

During your presentation

Remember, it pays to practice! You never know who will stop by to ask about your project. Clearly communicate your research and its value by implementing our Tips for Presenting a Scientific Poster .

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Report about the meeting of the COSMO Steering Committee (STC) Moscow, 6 and 7 September 2010

Aug 22, 2014

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Report about the meeting of the COSMO Steering Committee (STC) Moscow, 6 and 7 September 2010. Detlev Majewski, Head of STC Deutscher Wetterdienst, Offenbach, Germany. COSMO, before and …. after. COSMO STC Meeting, 6 and 7 Sept. 2010. Participants: D. Majewski (Germany)

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• lace groups
• operational runs
• high resolutions
• potential licence takers
• pp versus status

Presentation Transcript

Report about the meeting of the COSMO Steering Committee (STC) Moscow, 6 and 7 September 2010 Detlev Majewski, Head of STC Deutscher Wetterdienst, Offenbach, Germany

COSMO, before and …

COSMO STC Meeting, 6 and 7 Sept. 2010 Participants: D. Majewski (Germany) T. Charantonis (Greece) M. Ferri (Italy) M. Ziemianski (Poland) R. Dumitrache (for G. Stancalie, Romania) D. Kiktev (Russia) P. Steiner (Switzerland) M. Arpagaus (SPM) For VERSUS (after lunch break) : A. Raspanti, U. Damrath, V. Stauch

COSMO Science Plan 2010 - 2014 • Presentation by M. Arpagaus

COSMO Software, additional software Current status; see COSMO contract COSMO model including nudging data assimilation Interpolation program int2lm Proposal by P. Steiner Additional programs: fieldextra, VERSUS Requirements for COSMO-Software: Portable, documented (internal + external), supported Procedures for the proposal of new COSMO-Software

NCMS (United Arab Emirates) signed licence agreement in July 2010 Four more potential licence takers in the future: Brazil (INMET and DHN), Oman, Catalunya Support of licence takers (see Licence Contract): Installation of the COSMO software on customer‘s computer and second level support (by DWD only) Support of COSMO software for at least four years (all COSMO partners) How to use the licence fees? Further development of COSMO, e.g. mutual short-term visits in the framework of PPs, invitation of experts; external software contracts; participation at a conference with an oral presentation about COSMO related scientific results COSMO Licence Issues, Part I

DWD asks for 50% of the licence fees for providing support to the customers and (usually) the initial/lateral boundary data based on analyses/forecasts of the global model GME. How to apply for support funded from the licence fees? 1-page proposal to the COSMO SPM and Head of STC detailing aim of activity, persons involved and costs forseen. SPM and STC will decide on a propsal after consultation with the WG-Leader(s). COSMO Licence Issues, Part II

Current Users of HRM

Goal: Provide a medium-term perspective for current HRM users in developing countries. Proposal: Provide an old cycle (question: How old?) of the COSMO model without support to users in developing countries; see http://data.worldbank.org/about/country-classifications/country-and-lending-groups; here: Low-income economies ($995 or less) and Lower-middle-income economies ($996 to $3,945) Decision of STC needed until end of 2010 because HRM has to be phased out until 2012 (GRIB2, ICON for lateral boundary values, grid spacing of 7 km or less) Head of STC will prepare letter to be send to COSMO Directors. From developing countries viewpoint: COSMO model or WRF (NOAA/NCAR) as replacement of HRM COSMO model for developing countries

STC discussed the status of all PPs and PTs STC agreed to extend the following PPs: COLOBOC (by one year) CONSENS (by one year) STC agreed to create the new PP POMPA “Performance on massively parallel architectures” STC discussed the status and future development of PP VERSUS Status of PPs; New PP: POMPA; Status of VERSUS

Sochi 2014 (Winter Olympic) Brazil 2014 (Soccer World Cup) Brazil 2016 (Summer Olympics) Can the COSMO Partners offer some show pieces (FDPs, RDPs) to increase the visibility of COSMO? Head of STC will write a letter to the Directors of the COSMO Partners. COSMO and important sport events

What to do if a COSMO member cannot provide 2 FTEs for two or even three years? Head of STC will ask the President of DWD to write a letter of concern to the Director of the COSMO Partner involved to ask for proposals of how to alleviate the situation. Missing FTEs should not be due to a lack of focus at the service because of running other regional NWP models! FTE 2009/2010/2011

How to improve communication within STC and with Head of STC? Jour fixe SPM and head of STC once a month (phone call) Once a year Head of STC and SPM will write a short (1-2 pages) paper about COSMO progress for Directors Communication issues

COSMO-GM 2011 from 12 – 16 September in Rome (Italy) COSMO-GM 2012 from 10 – 14 September in Lugano (Switzerland) Next COSMO-GMs

Report of BRAC-Meeting 17 – 20 May 2010Supetar, Brac Island, CroatiaD. Majewski, DWD, Head of STC BRAC-HR BRainstorming on Advanced Concepts on High Resolution Modelling Workshop NWP at scales of a few hundreds of meters to a few kilometers

Background • General Assembly of ALADIN partners 2009 in Istanbul • Problems seen in HARMONIE/AROME integrations at high resolutions detected by HIRLAM: - Fireworks (precipitation, cold pools, wind gusts) - Stability of integration • Concerns about scalability of HARMONIE on future massively parallel computer systems • Strategic planning process for the next 5 – 10 years • Two-stage process: Brainstorming meeting in Brac in May 2010 Scientific vision workshop in early 2011

Known deficiencies by Sander Tijm • Daily cycle of convection • Outflow (how to verify?) • Low level clouds • Strength of convection

Daily cycle of convection by Sander Tijm

Outflow: Temperature Cold pools as seen in the 2m-temperature

Strength convection by Sander Tijm

Impact of horizontal diffusion by Sander Tijm

New computer architectures like multi-/many-core CPUs and GPUs (Graphics Processing Unit like NVIDIA) Massively parallel computer systems with > 100.000 cores. Mixed OpenMP / MPI parallelization. Portability of numerical model to different platforms. Scalability of numerical model on > 10.000 cores. Major challenges: Load balancing (e.g. physical processes) and efficient I/O on > 10.000 cores. Stability of operational runs using 100.000 cores (with a potential small mean time between interrupts!). Future HPC challenges

Scalability of COSMO-EU on 512, 1024 and 2048 coresof an IBM Blue Gene (PowerPC 450, 850 MHz) 24-h forecast; 665 x 657 gridpoints, 40 layers (852, 426, 213 gridpoints/core)

Workshop in Brac, Croatia Organisers J. F. Geleyn (ALADIN), J. Onvlee (HIRLAM), D. Klaric (RC LACE), P. Termonia (Belgium), C. Fisher (France) Participants About 23 particpants from ALADIN, AROME, HIRLAM, LACE groups and D. Majewski (COSMO) T. Davies (UKMO) E. Kallen (ECMWF)

Organisation of BRAC-HR Monday: Plenary with several key note lectures Tuesday and Wednesday: Working group meetings • WG1: Dynamical cores‘ development • WG2: Upper air physics • WG3: Physics – dynamics interface • WG4: Validation and verification • WG5: Nesting, LBC, coupling • WG6: Surface modelling Thursday: Reports of WGs and draft of standpoints

Outcome of BRAC-HR • „Official“ 12+6 page report by the organizing committee (probably mainly written by J. F. Geleyn) dated 20/08/2010 • This report distinguishes between: - areas of broad consensus (6 pages) - areas of divergence of opions (5 ½ pages) - attempt of a synthesis for future steps (1 page)

Areas of broad consensus At high resolution, stochastic point of view more and more important Increased sophistication for process description primarily for microphysics of precipitation and cloud-determination scheme(s) Some 3D-effects of radiation like slope and shadow of clouds Improvements of physics-dynamics interface needed For verification: Radar and satellite data Onset of (airmass) convection is one of the most fundamental problems to be solved

Areas with divergence of opinions Detailed priorities for the necessary evolutions of the diagnostic – validation – verification toolkit Evolution or substitution of the current AROME spectral SI/SL dycore; two extreme solutions: Spectral SI/SL vs. gridpoint RK (like WRF, COSMO) Relative priority to be asigned to the dynamical core issues (Météo France participants (F. Bouttier and C. Lac; see also paper by P. Benard and C. Lac) argue that the current dycore is the cause of the problems; J. F. Geleyn and many other participants (but not the COSMO representative) blame missing lateral mixing.

Summary and outlook Deep internal controversy between Météo France, ALADIN and HIRLAM about the cause of the problems of the current AROME and how to tackle them. To shed some light on the problem: - Run Weisman/Klemp (1982) test with AROME and COSMO-Model. - Compare operational forecasts of AROME and COSMO for common areas (Southwestern Germany, Netherlands, Belgium).

Orography (m) AROME (2.5 km) COSMO (2.8 km)

Temperature (°C) at 2m and wind at 10m 12 July 2010 00 UTC +12hAROME (2.5 km) COSMO (2.8 km)

Wind gusts (km/h) at 10m 12 July 2010 00 UTC +12hAROME (2.5 km) COSMO (2.8 km)

Temperature (°C) at 2m and wind at 10m 12 July 2010 00 UTC +14hAROME (2.5 km) COSMO (2.8 km)

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