Synthes Synex System User manual

Instruments and implants
approved by the AO Foundation
Synex System. An expandable vertebral
body replacement device.
Technique Guide

Introduction
Surgical Technique
Care and Maintenance
Product Information
Table of Contents
Synex System 2
AO Principles 4
Indications 5
Perform Corpectomy 6
Determine Implant Size 7
Fill with Bone Graft 8
Attach Headpieces to Parallel Distractor 9
Expand Implant 10
Verify Locking Ring is Closed 12
Apply Supplemental Fixation 13
Low Profile Parallel Distractor Disassembly 14
and Assembly
Implants 17
Instruments 19
Set List 22
Image intensifier control
Synthes Spine

Synex System
The Synex implant is an expandable vertebral body
replacement device:
–Available in several heights and various endplate configurations
– Self-locking to provide an efficient means of restoring proper
spinal alignment
–Rapid and controlled in situ expansion with minimal
instrumentation
– Convex endplates anatomically designed to minimize
subsidence while optimizing bone graft placement
following expansion
–Implants made from titanium alloy (Ti-6Al-7Nb)
Expansion mechanism
– Self-locking ratchet
–Each ratchet step equals 2.5 mm of distraction
–R
apid, controlled in situ expansion of the implant in the
corpectomy site
2Synthes Spine Synex System Technique Guide

Endplate design
–Large endplate contact surfaces designed to minimize
subsidence into adjacent vertebral bodies
– Convex surfaces match vertebral body endplate anatomy
– Teeth and spikes designed to minimize implant migration
– Kyphotic and lordotic configurations available
– Open and closed endplates available
Access for bone graft
–Large window for internal bone graft placement
after expansion
– Endplate preserves space for peripheral bone
graft placement
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In 1958, the AO formulated four basic principles, which have
become the guidelines for internal fixation.1They are:
–Anatomic reduction
–Stable internal fixation
–Preservation of blood supply
–Early, active mobilization
The fundamental aims of fracture treatment in the limbs and
fusion of the spine are the same. A specific goal is returning
as much function as possible to the injured neural elements.2
AO Principles as Applied to the Spine3
Anatomic alignment
Restoration of normal spinal alignment to improve the
biomechanics of the spine.
Stable internal fixation
Stabilization of the spinal segment to promote bony fusion.
Preservation of blood supply
Creation of an optimal environment for fusion.
Early, active mobilization
Minimization of damage to the spinal vasculature, dura, and
neural elements, which may contribute to pain reduction and
improved function for the patient.
1. M.E. Müller, M. Allgöwer, R. Schneider, and H. Willenegger: AO Manual of
Internal Fixation, 3rd Edition. Berlin; Springer-Verlag. 1991.
2. Ibid.
3. M. Aebi, J.S. Thalgott, and J.K. Webb. AO ASIF Principles in Spine Surgery.
Berlin; Springer-Verlag. 1998.
4Synthes Spine Synex System Technique Guide
AO Principles

Indications
The Synex implant is avertebral body replacement device
intended for use in the thoracolumbar spine (T1–L5) to
replace acollapsed, damaged, or unstable vertebral body
resulting from tumor or traumatic fracture. The Synex implant
can be packed with bone and should be used with Synthes
supplemental internal fixation systems, such as TSLP, VentroFix,
USS and Pangea. Synex implants are designed to provide
anterior spinal column support even in the absence of fusion
for aprolonged period.
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Perform Corpectomy
1
Choose the appropriate approach
Use alateral or anterolateral approach, depending
on the spinal level involved.
2
Perform corpectomy
Perform apartial or complete corpectomy as required.
Note: Remove the superficial layer of the cartilaginous
endplates to expose bleeding bone. Excessive removal of
subchondral bone may weaken the vertebral endplate. If
the entire endplate is removed, subsidence and aloss of
segmental stability may occur.
6Synthes Spine Synex System Technique Guide

Determine Implant Size
3
Determine implant size
Instruments
389.193 Parallel Distractor
8203 Preoperative Planner
Determine the height of the corpectomy site using the
parallel distractor. The scale on the handle of the parallel
distractor indicates the height of the implant needed to fill
the void. Use the preoperative planner and the following tips
for ease of implant selection:
– The height of the implant in its starting position should be
less than the undistracted corpectomy height.
–Subtract 4 mm from the value read on the distractor scale
to account for the height of the three tallest spikes.
–Themaximum expanded height of the implant should
exceed the measured corpectomy height.
4
Pick up implant
Instrument
389.204 Implant Holder
Grasp the implant with the implant holder close to the
locking ring, with the release opening facing the user.
Note: For the smallest implants (495.315 and 495.316)
place the implant holder close to the lower implant endplate
(see Step 8 on page 10).
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Fill with Bone Graft
5
Fill with bone graft
Prior to implantation, fill the implant endplates with bone
graft. Place additional bone graft on the contralateral side
of the corpectomy (which cannot be reached after insertion
of the Synex implant). Fill the hollow body of the implant
after expansion.
6
Insert implant
Guide and position the implant with the implant holder.
Ensure that the release opening is facing the implant
holder to allow repositioning if necessary.
Note: The optimal position for the implant is in the center of
the vertebral endplate. Maintain space around the endplate
of the implant to allow for peripheral bony fusion.
8Synthes Spine Synex System Technique Guide

Attach Headpieces to Parallel Distractor
7
Attach headpieces to parallel distractor
Instruments
389.205 Small Headpiece
389.206 Large Headpiece
Attach the appropriate headpieces onto the blades of the
parallel distractor for implant expansion. The headpiece sizes
correspond to the implant diameters. Use the headpieces
labeled “B” for blue Synex implants and headpieces labeled
“G” for green Synex implants.
Note: After use, press the buttons on the distractor blades
to remove the headpieces.
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Release button
for headpieces