Synthes Small Stature USS User manual

Instruments and implants
approved by the AO Foundation
Small Stature USS. Dual-opening, low
profile hooks and screws for spinal
fixation.
Technique Guide

Introduction
Surgical Technique
Product Information
Table of Contents
Small Stature USS 2
Indications 3
Preoperative Planning 4
Place Hook 5
Prepare Pedicle 7
Insert Screw 9
Contour Rod 10
Construct Assembly 12
Alternative Method of Construct Assembly 13
Distraction and Compression 15
Final Tightening 16
Attach Transconnector 18
Optional Techniques 19
Implants 21
Instruments 24
Set list 30
Image intensifier control
Synthes Spine

Small Stature USS
Features and benefits
Low-profile system
– For pediatric and small-statured patients
– Designed to minimize soft tissue interactions
Dual (side)-opening, top-tightening
– Reduces inventory
– Simplifies intraoperative procedure
– No preloading implants onto rod
Technique adaptable
– Designed to correct scoliosis either by segmental
correction or global derotation
Biomechanical strength
–Comparable to the Universal Spinal System
Versatile linkage mechanism
– Allows addition or removal of anchorage points
to an assembled construct
2Synthes Spine Small Stature USS

Indications
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The Synthes USS (including the Click’X, USS VAS variable axis
components, and Pangea), Click’X Monoaxial, Pangea
Monoaxial, Dual-Opening and the Small Stature USS (which
includes small stature and pediatric patients) are noncervical
spinal fixation devices intended for use as posterior pedicle
screw fixation systems (T1–S2), aposterior hook fixation
system (T1–L5), or as an anterolateral fixation system (T8–L5).
Pedicle screw fixation is limited to skeletally mature patients
with the exception of the Small Stature USS. These devices
are indicated for all of the following indications regardless of
the intended use: degenerative disc disease (defined as disco-
genic back pain with degeneration of the disc confirmed by
history and radiographic studies), spondylolisthesis, trauma
(i.e., fracture or dislocation), deformities or curvatures (i.e.,
scoliosis, kyphosis, and/or lordosis, Scheuermann’s disease),
tumor, stenosis, pseudoarthrosis, and failed previous fusion.
When treating patients with degenerative disc disease (DDD),
transverse bars are not cleared for use as part of the posterior
pedicle screw construct.
When used with the 3.5 mm/6.0 mm parallel connectors,
the Synthes USS (including the Click'X, USS VAS variable axis
components, and Pangea), Click'X Monoaxial, Pange Mono-
axial, and Dual-Opening USS can be linked to the CerviFix
system. In addition, when used with 3.5 mm/5.0 mm parallel
connectors, the Synthes Small Stature USS, can be linked to
the CerviFix system. When used with the 5.0 mm /6.0 mm
parallel connectors, the Synthes Small Stature USS can be
linked to the Synthes USS (including the Click'X, USS VAS
variable axis components, and Pangea), the Click'X Monoax-
ial, PangeaMonoaxial, and Dual-Opening USS systems.
In addition, Synthes USS (including the Click’X, USS VAS
variable axis components, and Pangea), Click’X Monoaxial,
PangeaMonoaxial and the Dual-Opening USS can be inter-
changed with all USS 6.0 mm rods and transconnectors.

Preoperative Planning
4Synthes Spine Small Stature USS
1
Preoperative planning
Preoperative planning is critical in the preparation for spinal
surgery.
A radiographic evaluation (AP and lateral standing, and AP
lateral bending) should be completed for proper diagnosis
prior to surgical intervention.
Additional evaluation, such as CT scans, may be required if
there are any anatomic variations.
A preoperative planner may be used to plan the hook and
screw layout. A sample of the Small Stature USS planner is
shown on the right.
Small Stature USS Preoperative Planner
Dual-Opening Hooks*
Dual-Opening Screws*
Lamina Hooks
Side-opening Front-opening
Small x98.308 x98.309
Medium x98.318 x98.319
Large x98.328 x98.329
Posterior View
* I mplants are available in both Stainless Steel and Titanium.
Replace “X” with a “2” for Stainless Steel or “4” for Titanium.
Illustrations not shown actual size.
Tall Body Lamina Hooks
Side-opening Front-opening
Small x98.209 x98.210
Medium x98.211 x98.212
Large x98.213 x98.214
Thoracic Lamina Hooks
x98.338, Side-opening
x98.339, Front-opening
Transverse Process Hooks, Right
x98.376, Side-opening
x98.378, Front-opening
4.2 mm Screws
Length
x98.401 25 mm
x98.402 28 mm
x98.403 30 mm
x98.404 32 mm
x98.405 35 mm
x98.406 38 mm
x98.407 40 mm
5.0 mm Screws
Length
x98.409 25 mm
x98.410 30 mm
x98.411 35 mm
x98.412 40 mm
x98.413 45 mm
6.0 mm Screws
Length
x98.415 30 mm
x98.416 35 mm
x98.417 40 mm
x98.418 45 mm
x98.419 50 mm
x98.420 55 mm
7.0 mm Screws
Length
x98.422 30 mm
x98.423 35 mm
x98.424 40 mm
x98.426 45 mm
x98.427 50 mm
x98.428 55 mm
x98.429 60 mm
Transverse Process Hooks, Left
x98.377, Side-opening
x98.379, Front-opening
Angled Lamina Hooks
x98.206, Side-opening
x98.207, Front-opening
Pedicle Hooks
x98.348, Side-opening
x98.349, Front-opening
© SYNTHES Spine 2000
Right Left
Original Instruments and Implants of the Association for the Study of Internal Fixation–AO/ASIF SYNTHES and ASIF are registered trademarks of SYNTHES (USA) and SYNTHES AG Chur.
2
Prepare lamina
Instrument
388.521 LaminaFinder
Use the laminafinder to separate the ligamentum flavum
from the underside of the laminato ensure good bony
contact with the laminahook.

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Place Hook
3
Prepare pedicle
Instrument
388.511 Pedicle Finder
Using the pedicle finder, pierce the facet capsule and locate
the pedicle.
Remove asmall piece of the inferior articular process to
ensure proper seating of the pedicle hook (up-going only).
4
Place hook
Instruments
388.612 Hook/Screw Holder (“Hex Stick”)
388.622 Handle, for hook/screw holder
388.631 Hook Positioner
Align the hex on the “hex stick” holder with the hex in the
top of the appropriate hook and secure with the coupling
screw. Snap the “hex stick” into the handle by depressing
the button on the handle.
Place the hook in the desired location. The hook positioner
may also be used to facilitate placement of the hook.
After the hook is properly seated, remove the handle. The
“hex stick” can remain attached to the hook.

4
Place hook continued
Alternative Technique
Instrument
388.522 Hook Holding Forceps
Attach the appropriate hook to the hook holding forceps,
and place the hook in the desired location.
The hook positioner may be used to facilitate placement of
the hook.
After the hook is properly seated, remove the hook holding
forceps and repeat hook placement at each hook site, as
determined in the preoperative plan.
5
Place remaining hooks
Repeat Steps 2–4 to place hooks at each hook site, as deter-
mined in the preoperative plan.
6Synthes Spine Small Stature USS
Place Hook continued

7
Prepare pedicle
Instruments
388.54 Probe
388.544 Pedicle Probe, for 4.2 mm screws
388.545 Straight Ball Tip Probe
388.546 Curved Ball Tip Probe
388.55 Awl
388.551 Awl, for 4.2 mm screws
Use the awl or awl for 4.2 mm screws to perforate the
posterior cortex of the pedicle.
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Prepare Pedicle
6
Identify pedicles
The entry point for each lumbar pedicle is at the intersection
of ahorizontal line bisecting the transverse process and a
vertical line drawn along the lateral border of the superior
articular process.
The point of entry for each thoracic pedicle is at the intersec-
tion of aline through the transverse processes and aline
through the inferolateral edge of the facet joint.

Prepare Pedicle continued
8Synthes Spine Small Stature USS
7
Prepare pedicle continued
Open the pedicle canal, using the probe or the pedicle probe
for 4.2 mm screws. Displace the soft cancellous bone by ad-
vancing the probe into the pedicle canal. If the probe resists
advancement, use radiographic imaging to check position
and orientation. Care should be taken to not perforate the
walls of the pedicle.
Palpate the walls of the pedicle using astraight ball tip probe
or curved ball tip probe. Use radiographic imaging to confirm
position and orientation.
8
Select proper screw length
Instrument
388.545 Straight Ball Tip Probe
Place the straight ball tip probe into the pedicle canal to
determine proper screw length.
This instrument has depth markings at 25 mm, 30 mm,
40 mm, 50 mm, 60 mm and 70 mm.
Position all screws approximately 50–80% into the vertebral
body.*
* M.E. Müller, M. Allgöwer, R. Schneider, H. Willenegger, Manual of Internal
Fixation, 3rd Edition (Berlin: Springer-Verlag, 1991): p. 668.

Insert Screw
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9
Insert screw
Instruments
388.612 Hook/Screw Holder (“hex stick”)
388.622 Handle, for hook/screw holder
Align the hex on the “hex stick” with the hex in the top
of the appropriate dual-opening screw and secure with
the coupling screw. Snap the “hex stick” into the handle
by depressing the button on the handle.
Insert the dual-opening screw into the prepared pedicle.
After the screw has been inserted, remove the handle by
depressing the button, leaving the “hex stick” in place, if
desired.
Alternative instruments
388.335 4.0 mm Hexagonal Screwdriver
388.337 4.0 mm Hexagonal Screwdriver Shaft
388.38 Holding Sleeve
The 4.0 mm hexagonal screwdriver may also be used for
screw insertion.
The handle used with the 4.0 mm hexagonal screwdriver
shaft offers an alternative method for screw insertion.
The holding sleeve may be used with either screwdriver to
retain the screw during initial insertion into the pedicle.
Important: Care should be taken to align the screws along
the same longitudinal axis to facilitate rod placement. This
may require adjusting the screws so that they are all at ap-
proximately the same height.

11
Cut rod if necessary
Instrument
388.72* Rod Cutter
Adjust the rod length using the rod cutter. All rod cutting
should take place outside the operative field.
10 Synthes Spine Small Stature USS
Contour Rod
10
Determine rod contour
Instruments
388.906 Coated Rod Template, 150 mm
388.907 Coated Rod Template, 500 mm
Once the screws and hooks have been placed and their
position confirmed radiographically, determine the contour
of the rod by using the appropriate coated rod template.
*Also available

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12
Contour rod
Instruments
388.911 Bending Iron, left
388.922 Bending Iron, right
388.961 Rod Bender, with bend radius
adjustment
Contour the rod to match the rod template, using the rod
bender or the bending irons (Figure 1 or Figure 2).
Match contour of rod to template (Figure 3).
Figure 1
Figure 3
Figure 2

14
Apply collars and nuts
Instruments
388.152 Socket Wrench with Straight Handle, for
12-point nut
388.153 Collar Positioner
388.755 Impactor
Load acollar for 5.0 mm rods into the collar positioner. Note
that the collar can be loaded in only one direction.
Place the loaded collar positioner over the head of the im-
plant and seat the collar. If light impaction of the collar is
necessary for final seating, remove the collar positioner and
use the impactor with asmall mallet.
Place a12-point nut over the construct and tighten, using
the socket wrench.
12 Synthes Spine Small Stature USS
Construct Assembly
13
Align rod to hooks and screws
Instruments
388.441 Rod Holding Forceps, for 5.0 mm rods
388.49 Rod Crimping Pliers, for side-opening
implants
388.941 Rod Pusher, for 5.0 mm rods
Position the rod parallel to the side opening of the screws
and hooks, using the rod holding forceps.
Introduce the rod into the side opening of the hook or screw,
using the rod crimping pliers. The rod pusher may also be
used to aid in manipulating the rod into place.

Alternative Method for Construct Assembly
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15
Load collar
Instrument
388.506 Rod Introduction Pliers
The rod introduction pliers may be used with the “hex stick”
for construct assembly.
Load acollar onto the barrel of the rod introduction pliers.
Note that the collar can be loaded on the pliers in only one
direction.
16
Engage rod
Instruments
388.413 Distraction Forceps, for 5.0 mm rods
388.606 Distraction Clip, for hook/screw holder with
4.0 mm hex
Position the barrel of the rod introduction pliers over the
“hex stick” and slide it down to the construct. Engage the
rod with the jaw opposite the barrel of the rod introduction
pliers and squeeze the handle to insert the rod into the hook
or screw.
If biplanar reduction of the rod is necessary, use the distrac-
tion clip and the distraction forceps with the rod introduction
pliers to guide the rod into the hook or screw opening.
Place the distraction clip over the “hex stick.” Use the dis-
traction forceps against the distraction clip while squeezing
the rod introduction pliers until the rod is seated into the
hook or screw.
Collar

Alternative Method for Construct Assembly continued
14 Synthes Spine Small Stature USS
17
Seat collar
Instruments
388.132 Socket Wrench with T-Handle,
for 12-point nut
388.631 Hook Positioner
Use the hook positioner to tap the collar retaining sleeve and
seat the collar onto the implant assembly (Figure 1).
Once the collar is pushed down over the implant, remove the
distraction clip (if necessary) and the rod introduction pliers.
Place a12-point nut over the construct and tighten with the
socket wrench (Figure 2).
Figure 1
Figure 2

Distraction and Compression
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19
Distraction and compression, if necessary
Instruments
388.413 Distraction Forceps, for 5.0 mm rods
388.424 Compression Forceps, for 5.0 mm rods
For distraction, use the distraction forceps for 5.0 mm rods.
Make sure all nuts are loose before distracting against the
point of fixation. Once in the desired position, tighten the
nut using asocket wrench.
For compression, use the compression forceps for 5.0 mm
rods. Make sure all nuts are loose before compressing
against the point of fixation. Once in the desired position,
tighten the nut using asocket wrench.
18
Determine point of fixation
Instrument
388.441 Rod Holding Forceps, for 5.0 mm rods
If necessary, grasp the rod with the rod holding forceps and
slowly rotate the rod in the proper direction. Make sure all
nuts are loose before rotating the rod.
Use the rod holding forceps as apoint of fixation, if neces-
sary, against which to distract or compress.

Final Tightening
16 Synthes Spine Small Stature USS
20
Tightening of construct
Instruments
388.142 Socket Wrench with Straight Handle,
5 mm width across flats
388.266 10 Nm Torque Limiting Wrench, for
12-point nut
388.335 4.0 mm Hexagonal Screwdriver
388.612 Hook/Screw Holder (“Hex Stick”)
388.622 Handle, for hook/screw holder
The 10 Nm torque limiting wrench must be used for final
construct tightening.
The torque limiting wrench is used with either the 4.0 mm
hexagonal screwdriver or the 5 mm socket wrench with
straight handle and the “hex stick” to tighten all the nuts.
Important: This wrench must be used to ensure that the
appropriate amount of torque is applied for final tightening
of the construct.
Note: Any distraction or compression must be completed
prior to final tightening.
Applying countertorque using the 4.0 mm hexagonal
screwdriver
Place the torque limiting wrench over the 12-point nut.
Insert the 4.0 mm hexagonal screwdriver through the torque
limiting wrench and into the hexagonal socket of the hook
or screw. Hold the screwdriver stationary and turn the torque
limiting wrench clockwise to secure the nut.
The torque limiting wrench will “click” at the preset torque
of 10 Nm. No additional tightening is required after the first
“click.”

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Applying countertorque using the 5 mm socket wrench
Place the torque limiting wrench over the “hex stick” and
engage the 12-point nut. Insert the 5 mm socket wrench
through the torque limiting wrench to engage the 5 mm
hex on the “hex stick”. Hold the 5 mm socket wrench
stationary and turn the torque limiting wrench clockwise
to secure the nut.
The torque limiting wrench will “click” at the preset torque
of 10 Nm. There is no additional tightening required after
the first “click.”

Attach Transconnector
18 Synthes Spine Small Stature USS
21
Attach transconnector
Instruments
388.31 Long Small Hexagonal Screwdriver
388.864 Measuring Template, for Low Profile
Transconnector for 5.0 mm rods
The low profile transconnector is used as aconstruct stabi-
lizer to reduce rotation.
Measure distance between rods
Use the measuring template to measure the distance
between the two rods.
Secure transconnector to rods
Loosen all of the setscrews and place the low profile trans-
connector of the appropriate length onto the rods. Use the
long small hexagonal screwdriver to secure the transconnec-
tor to the rods by tightening the setscrews on each end.
Note: For transconnectors with Stargrind, tighten the
stargrind setscrew to lock the angle between the rods.
When using an adjustable length transconnector, adjust the
distance between the rods, if desired, by compressing or dis-
tracting; then tighten the center setscrew on the rotating
shaft, using the long small hexagonal screwdriver.
Note: If any part of the construct requires further adjust-
ment, all transconnector setscrews must be loosened. After
final adjustment, retighten the setscrews.