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

Expand Implant
8
Expand implant
Instrument
389.193 Parallel Distractor
Alternative instruments
01.807.003 Synex Endoscopic Spreader Instrument Set
389.202 Synex Low Profile Parallel Distractor
Refer to page 14 for additional information on the Synex
low profile parallel distractor.
Refer to the Synex Endoscopic Spreader Instrument Set Tech-
nique guide for additional information on that instrument.
Expand the Synex implant in situ using the parallel distractor.
If necessary, the implant holder may be used simultaneously
to maintain implant position during distraction.
Expand the implant until the desired amount of spinal
correction is achieved. Each step of the ratchet mechanism
produces 2.5 mm of distraction. A stop will engage if the
implant reaches its maximum height, preventing the implant
from separating.
Note: If ataller implant is required, remove the implant as
described on page 11 (“Implant repositioning”) and replace
it with an appropriately sized implant.
When expanding the shorter Synex implants, the parallel
distractor may press against the implant holder instead of
the implant endplate.
10 Synthes Spine Synex System Technique Guide

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Implant repositioning (optional)
Instrument
389.201 Disconnecting Instrument
If it is necessary to reposition the implant, use the disconnecting
instrument to collapse the expanded implant to its starting
position. Introduce the disconnecting instrument into the slot
between the two ends of the locking ring and turn it
one-quarter (1/4) of arevolution. Remove the implant using
the implant holder.
Note: Do not reuse Synex implants once they have been
implanted or expanded.

Verify Locking Ring is Closed
12 Synthes Spine Synex System Technique Guide
9
Verify locking ring is closed
After expansion, check the closure of the locking ring. If there
is agap of approximately 1 mm (Figure 1), the implant height
is secure. If the slot is larger (Figure 2), expand the implant
slightly to engage the locking ring.
10
Place bone graft
Radiographically verify the position of the implant in relation
to the vertebral bodies in the frontal and sagittal planes
intraoperatively.
Pack bone graft in and around the cage, especially the
anterior zone of the corpectomy site.
Figure 1 Figure 2

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Apply Supplemental Fixation
11
Apply supplemental fixation
To ensure stability of the spine and maintain adequate
compression on the Synex construct, the Synex system is
indicated for use with supplemental anterior and/or posterior
fixation. The following systems may be used: VentroFix, TSLP,
Pangeaand/or USS. Refer to the appropriate technique
guides for information on the indications, descriptions,
contraindications, precautions, warnings, and potential
risks associated with these supplemental fixation systems.

14 Synthes Spine Synex System Technique Guide
Disassembly
1
Open distractor
Instrument
389.202 Synex Low Profile Parallel Distractor
Open the distractor completely by turning the T-handle clock-
wise until the red line (a) on the shaft is visible. Turn the locking
bolt (b) counterclockwise until it disconnects from the spreading
instrument. Remove the locking bolt from the shaft.
2
Disengage T-handle
Disengage the T-handle from the hex-head (c) by pulling on
the distractor blade.
Synex Low Profile Parallel Distractor Disassembly and Assembly
a
c
a
b

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3
Remove T-handle
Remove the T-handle by turning it clockwise until
unthreaded and then pull it out of the shaft.
4
Remove hex-head
Remove the hex-head by turning it counterclockwise.

Synex Low Profile Parallel Distractor Disassembly and Assembly continued
16 Synthes Spine Synex System Technique Guide
Assembly
After cleaning, assemble the spreading instruments.
1
Insert hex-head
Thread the hex-head clockwise into the distractor blade until
fully seated.

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2
Insert T-handle
Insert the T-handle into the distractor shaft and thread counter-
clockwise to the red line. Attach the hex-head to the T-handle.
3
Insert locking bolt
Insert the locking bolt into the T-handle and turn clockwise
until fully seated.

Implants
18 Synthes Spine Synex System Technique Guide
Note: Implants shown actual size.
Synex with small endplates (green)
The green Synex implants (small endplates) are used
in the upper to midthoracic spine. They are available
with -5° kyphotic endplates in arange of heights.
Angle Height Range Angulation
495.320 -5º 20 mm–25 mm kyphotic
495.315 -5° 23 mm–31 mm kyphotic
495.318 -5° 28 mm–40 mm kyphotic
495.325 -5° 36 mm–56 mm kyphotic
Synex with small endplates (green), open
Angle Height Range Angulation
04.807.120 -5° 20 mm–25 mm kyphotic
04.807.123 -5° 23 mm–31 mm kyphotic
04.807.128 -5° 28 mm–40 mm kyphotic
04.807.136 -5° 36 mm–56 mm kyphotic
21 mm x 22 mm
21 mm x 22 mm
-5°
495.318

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Synex with large endplates (blue)
The blue Synex implants (large endplates) are used in the
lower thoracic and lumbar spine. They are available in six
height ranges with four different angulations to meet the
anatomical needs of the spine.
Angle Height Range Angulation
495.316 0° 23 mm–31 mm parallel
495.317 0° 26 mm–36 mm parallel
495.319 0° 31 mm–46 mm parallel
495.321 10° 33 mm–48 mm lordotic
495.323 20° 37 mm–55 mm lordotic
495.327 -6° 45 mm–73 mm kyphotic
Synex with large endplates (blue), open
Angle Height Range Angulation
04.807.223 0° 23 mm–31 mm parallel
04.807.226 0° 26 mm–36 mm parallel
04.807.231 0° 31 mm–46 mm parallel
04.807.233 10° 33 mm–48 mm lordotic
04.807.237 20° 37 mm–55 mm lordotic
04.807.245 -6° 45 mm–73 mm kyphotic
25 mm x 28 mm
25 mm x 28 mm
0° 10° 20° -6°
495.327495.323
495.321
495.319