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Fracture Fixation for Spine

USS Fracture SystemSurgical Technique

Image intensifier control

This description alone does not provide sufficient background for direct use of DePuy Synthes products. Instruction by a surgeon experienced in handling these products is highly recommended.

Processing, Reprocessing, Care and MaintenanceFor general guidelines, function control and dismantling of multi-part instruments, as well as processing guidelines for implants, please contact your local sales representative or refer to:http://emea.depuysynthes.com/hcp/reprocessing-care-maintenanceFor general information about reprocessing, care and maintenance of Synthes reusable devices, instrument trays and cases, as well as processing of Synthes non-sterile implants, please consult the Important Information leaflet (SE_023827) or refer to: http://emea.depuysynthes.com/hcp/reprocessing-care-maintenance

USS Fracture System Surgical Technique DePuy Synthes 1

Table of Contents

Implants 2

Principle of fracture clamps 3

Indications/Contraindications 4

Surgical Technique 5

Fractures with intact posterior wall 7

Fractures with fractured posterior wall 9

Assembling the cross-link system 14

Techniques depending on fracture type 18

Reduction of spondylolisthesis 19

Notes for the surgeon 21

Implants 22

Instruments 25

Bibliography 28

2 DePuy Synthes USS Fracture System Surgical Technique

Implants

Transpedicular Schanz Screw with dual core Length 180/35 mm – B 5.0 mm (496.711–715)* – B 6.2 mm (496.721–725)*

Fracture Clamp for Rods – B 6.0 mm, low profile (498.831)*

Fracture Clamp for Rods

– B 6,0 mm, for cranial end (498.833)*

Rod B 6.0 mm, hard

– length 50, 75 and 100 mm (498.102–104)* – length 125 and 150 mm (498.105–106)*

Cross-Link Clamp for Rods

– B 6.0 mm, preassembled (498.813)*

Cross-Link Rod B 3.5 mm

– length 40 mm (496.930)* – length 50 mm (496.950)* – length 60 mm (496.970)* – length 70 mm (496.980)* – length 80 mm (498.120)*

Fixation Ring for Rods

– B 6.0 mm (498.911)*

Transpedicular Schanz Screw with dual core and double thread

Thread length 40–50 mm – B 6.2 mm (496.776–778)* – B 7.0 mm (496.796–798)*

* All Implants are also available sterile packed. Add suffix “S” to article number.

15º15º9º15º


Principle of fracture clamps

Controlled reduction due to the free angular play of ±15°(fracture clamp for cranial end: +9°/–15°)


– Preoperative X-ray – Postoperative X-ray – Fusion of T12/L2 – Transpedicular defect

filling of L1

– Preoperative CT scan – 19-year-old male – Unstable burst fracture of L1

Indications/Contraindications

The USS Fracture system is a posterior thoracolumbar pedi-cle screw fixation system intended to provide precise and segmental stabilization of the spine in skeletally mature patients. The application area in patients suffering from trauma or tumor disease is usually at the thoracolumbar junction (T12/L1), but can be extended from T6 down to the sacrum (S1).

Indications – Fractures: unstable fractures of the thoracic, lumbar

and lumbo sacral spine and fractures associated with unacceptable deformities. (Discoligamentous disruptions or previous laminectomies do not constitute contraindi-cations.)

– Tumours/infections – Posttraumatic deformities – Spondylolisthesis

Contraindications – The USS Fracture System should not be used above T6

on the spinal column since the pedicles at this point are too narrow and cannot therefore ensure a sufficiently secure screw purchase.

– In fractures and tumors with severe anterior vertebral body disruption, an additional anterior support or col-umn reconstruction is required

– Osteoporosis

Pedicle 8

30

40

50

09_02 USS II von 07_02 USS Paediatric –von 08_02 Ped.Hooks

388.550 388.540

Schanz 03


Surgical Technique

1. Locate and open pedicles

Locate the pedicles.1 Open the pedicles using the Pedicle Awl B 4.0 mm (388.550) to a depth of 10 mm and the Pedicle Probe B 3.8 mm (388.540). The pedicle probe has markings at 30, 40 and 50 mm for checking the depth of pedicle/ver-tebral body penetration. Do not penetrate the anterior wall of the vertebral body. Using the hook of a depth gauge, probe the drilled channel to check that the channel is fully intact and that the spinal canal has not been opened.

2. Insert Kirschner wires

Insert 2 mm Kirschner wires and check that they are correctly positioned under the image intensifier (A/P, lateral and orthograde).

3. Replace Kirschner wires with Schanz screws

Insert the Schanz screws using the T-Handle (395.380) or Universal Chuck (393.100).

The Schanz screws should be inserted under lateral image intensifier control. The tips of the Schanz screws must not penetrate the anterior cortex.

1 Aebi et al. (1998), 102sq.

Schanz 04

Schanz 04

Z.5.1

9° 15°


4. Assemble USS fracture clamps and rod

Select the appropriate rod length. Take any necessary dis-traction into account when determining the length of the rod.

Place the clamps on the Schanz screws, push the rod through both clamps and push the entire construction toward the spine.

A slight resection of the spinal process will cause the assem-bly to lie close to the lamina.

Note: The rod comes to rest medially.

4a. Assembly with USS fracture clamp for the cranial end (optional)

The Fracture Clamp for Rods 498.833 can also be used for the cranial end. Since this clamp is firmly fixed to the rod, only one clamp can be used on each side. This clamp pre-vents the rod from jutting out at the cranial end, thereby protecting ad jacent mobile segments. The cranial fracture clamp is fixed to the vertical rod using the Socket Wrench 6.0 mm (388.140).

Surgical Technique

Schanz 06

10°

5 mm = 10°

10°

10°

10 mm = 10°

10°

Z.5.1


Fractures with intact posterior wall

Principle of kyphosis correction with intact posterior wall

Pressing the Schanz screws together dorsally lordoses the ad jacent vertebrae around the pivot point (red circle) of their facing posterior edges. The clamps on the rod move toward the centre. The fracture clamps must be able to slide freely along the rod, otherwise kyphosis correction will not be achieved.

Principle of kyphosis correction with the cranial clamp with an intact posterior wall (optional)

The use of the cranial fracture clamp allows correction of 10° in each case by moving the caudal clamp 10 mm (guide distance).

Z.6a.1

Z.Schanz 05a


5a. Locate Socket Wrench on both caudal Schanz screws and lordose the spine

Tilt both posteriorly projecting caudal screws cranially to lordose the spine. Secure the clamps/Schanz screws in the desired position using the Socket Wrench B 11 mm (394.701).

Note: It is absolutely essential that the blue-marked Socket Wrench B 11 mm (394.701) is used for the low-profile frac-ture clamps.

6a. Locate Socket Wrench on both cranial Schanz screws and lordose the spine

Repeat the above procedure for the cranial Schanz screws: Tilt in the caudal direction to complete the lordosing operation and secure in the desired position.

Fractures with intact posterior wall

Schanz 06

10°

5 mm = 10°

10°

Z.Schanz 5.2.1

10°

10 mm = 10°

10°


Fractures with fractured posterior wall

Principle of kyphosis correction with fractured posterior wall

Since a reduction produced by pressing the Schanz screw ends together produces undesirable compression on the destroyed posterior wall of the vertebral body, with the associated risk of fragment dislocation into the spinal canal, every clamp on the rod must be secured by a Fixation Ring for Rods B 6.0 mm (X98.911). This shifts the centre of rota-tion (red circle) to the level of the rod.

5 mm gaps between the fixation rings and the clamps allow kyphosis correction of 10 degree in each case (guide value).

Principle of kyphosis correction with the cranial clamp with fractured posterior wall (optional)

The use of the cranial fracture clamp allows correction of 10° in each case by moving the caudal clamp 10 mm (guide distance). A fixation ring must be used as a stop.

Zeichnung 5b

Z. Schanz 6


5b. Mount fixation rings according to the degree of lordosing

Pick up fixation rings using the Screwdriver, hexagonal (314.070) and the Holding Sleeve with Catches (388.363), locating the holding sleeve on the head of the set screw. Secure the fixation rings between the fracture clamps ac-cording to the desired degree of lordosing.

6b. Locate Socket Wrench and lordose the spine

Locate the Socket Wrench B 11 mm and create the corre-sponding lordosis by tilting the Schanz screws as described under 5a and 6a.


Z Schanz.7


7. Fix the clamps on the rodsUsing the Socket Wrench 6.0 mm (388.140), tighten the set screws to fix the fracture clamps on the vertical rods.

Note: If the cranial clamp is used, the caudal fracture clamps are fixed to the vertical rods by tightening the set screws with the Socket Wrench 6.0 mm.

Z. Schanz 9

Z.Schanz.8

Z.8.1



8. If required: Distraction with the Spreader Forceps under image intensifier control

Using the Socket Wrench 6.0 mm, loosen the set screws on the fracture clamps for the relevant vertebra and perform careful distraction if this is necessary to complete the ana-tomical reduction and restore the original level of the frac-tured vertebral body.

Note: If the cranial clamp is used, distraction can only be performed with the caudal clamp.

9. Remove fixation rings

When reduction is complete, tighten the set screws and remove the fixation rings.

Z. 10 Schanz

Z. 10 Schanz

45°

0°


10. Trim Schanz screws using the Bolt Cutter

When reduction is complete and the assembly has been secured, trim the Schanz screws to the required length us-ing the Bolt Cutter (Handle 391.780/790 and Bolt Cutting Head B 5.0 mm 391.771).

Using the Bolt CutterAssemble the Bolt Cutter and place in the neutral position (you should be able to see through the 5 mm hole). Position the handles, one on top of the other, on the bolt cutting head like the hands of a clock. Slide the bolt cutting head over the Schanz screw.

Pull the handles apart to an angle of approximately 45° until the Schanz screw audibly breaks.

Return the handles to the original position and move the bolt cutting head to the next Schanz screw. The previously cut screw shaft will fall out during this operation.

Note: If the cut screw shaft does not fall out of its own accord, it can be pushed out using the Cancellous Bone Impactor, straight (394.570) or the shaft of another Schanz screw. If this is not possible, the bolt cutting head will have to be dismantled and the screw shaft pushed out of the inner bolt.

Z Seite9 oben

Schanz 10 S24


Cross-links are transverse stabilizers that link the two vertical rods, thereby increasing the stiffness of the construct signifi-cantly. They are recommended for unstable fractures and multisegmental constructs.

1. Pick up first Cross-Link Clamp

Assemble the Small Screwdriver, hexagonal (314.070) and the Holding Sleeve with Catches (388.363). To pick up the preassembled Cross-Link Clamp for Rods B 6.0 mm (498.813), insert the hexagonal screwdriver into the set screw on the clamp, push down the holding sleeve and clip the catches onto the sleeve of the preassembled clamp.

2. Mount first Cross-Link Clamp

Pull the holding sleeve back slightly, place the clamp onto the rod and release the holding sleeve.

Assembling the cross-link system

Schanz 11 S24

2

1


3. Insert cross-link rod

The special design of the cross-link sleeve with its two re-cesses on the top allows the cross-link rod to be angled up to ±20° to suit the anatomical situation.

Determine the appropriate length of the B 3.5 mm cross-link rod. If necessary, cut the rod to length using the USS Rod Cutting and Bending Device (388.750).

Hold the clamp with the small hexagonal screwdriver and introduce the B 3.5 mm cross-link rod through the hole in the Cross-Link Clamp (1). If necessary, use the Holding For-ceps for USS Rods B 3.5/4.5 mm (388.450) to introduce the cross-link rod. Tighten the set screw of the Cross-Link Clamp with the small hexagonal screwdriver (2).

S05a

S25 b


4. Mount second Cross-Link Clamp

Repeat the procedure described in step 1 (page 14) for the second clamp on the opposite rod. Introduce the B 3.5 mm cross-link rod through the second clamp so that it protrudes by 5 mm beyond the clamp. Tighten the set screw with the small hexagonal screwdriver.

5. Distract cross-link assembly (optional)

Loosen one of the set screws. Place the Holding Forceps for USS Rods B 3.5/4.5 mm (388.450) next to the clamp and use the Spreader Forceps for Pedicle Screws (388.410) to exert distraction. Retighten the set screw with the small hexagonal screwdriver.

Assembling the cross-link system

USS Titelbild

USS Titelbild


6. Check all set screws on the system

When the system is fully assembled, check that all screws are securely tightened.

Z. Schanz. S.12.eps


Techniques depending on fracture type

Fracture of the posterior elements of the spine or disruption with distraction

In these indications, the USS Fracture System is used as a tension-band wiring system. Reduce the fracture as de-scribed under 5a/6a, then perform appropriate compression using the fixation rings and the Compression Forceps (388.422).

Complete disruption of the anterior and posterior elements of the spine with rotation

In these indications, the USS Fracture System is used as a neutralization system. If necessary, perform compression using the fixation rings and the Compression Forceps (388.422). For added stability, the additional use of one or two cross-link stabilizers to produce a frame construction is recom-mended.

Persisting wedge vertebra after reduction

If a fractured vertebra retains its wedge shape after reduc-tion because the disc is torn and lordosing of the adjacent vertebrae causes the intervertebral space to gape, but does not straighten the vertebral body, then subsequent kyphos-ing can be expected. Within a few years the disc will ag-glomerate and the correction will be lost.

In order to prevent this, a ventral intervertebral bone graft spondylodesis with bone graft is recommended in a second procedure.

Z. Reposition...S.13/1



Reduction of spondylolisthesis

1. Insert Transpedicular Schanz Screws

Insert the Transpedicular Schanz Screws with dual core and double thread (496.776–778 or 496.796–798) into the displaced vertebra (cranial) as described in steps 1–3 on page 5. Normal Schanz screws are inserted into the caudal vertebra. Assemble USS fracture clamps and rods as de-scribed in step 4 (page 6). Secure caudal fracture clamps to the rod.

2. Perform reductionSlide the USS Reduction Sleeve (388.931) and USS Nut, knurled (388.932) over the Schanz screws with double thread. Turn the nuts on both sides until the desired reduc-tion is achieved.



Reduction of spondylolisthesis

3. Tighten fracture clamps

Remove the USS Nuts, kurled and tighten the fracture clamps using the Socket Wrench B 11 mm (394.701).

4. Fix fracture clamps on the rods and trim Schanz screws

Remove the USS reduction sleeves. Fix the USS fracture clamps using the Socket Wrench 6.0 mm as described in step 7 (page 11). Trim the Schanz screws with the Bolt Cutter as described in step 10 (page 13).


Notes for the surgeon

Preoperative planningEvaluation by imaging methods is essential for assessing spinal pathology.

Image intensifier controlThis is essential during the operation in order to avoid lesions of the spinal canal, nerve root damage and vascular injuries.

Filling defective vertebral bodiesAny bone defect in the vertebral body should be filled with autologous bone or – if significant defects affecting the spi-nal mechanics are present – with a bone graft. This will both prevent any corresponding loss of correction and minimize the risk of implant fractures.

Assembly across several segmentsFor the management of fractures, the Schanz screws are im-planted in the adjacent cranial and caudal vertebral bodies. Normally this stabilization across two mobile segments is sufficient. Non-traumatic indications or tiered fractures may require bridging of additional vertebrae. In such cases, the formation of a frame construction with cross-links is recommended.

Postoperative managementEarly mobilization is permissible, provided a three-point cor-set is worn postoperatively to prevent flexion and extension.

Implant removalAfter fracture consolidation (9–12 months), removal of the implant is recommended in order to minimize any impair-ment of the paravertebral muscles. The implant should not be removed if tumours are present.

The clamps are loosened using the Socket Wrench B 11 mm (394.701), while the set screws are loosened with the Socket Wrench 6.0 mm (388.140). The rod and clamps can then be removed from the Schanz screws.

Next, grasp the ends of the Schanz screws with the screw forceps or the T-handle and pull the screws out.


496.711 Transpedicular Schanz Screw B 5.0 mm with dual core, length 180/35 mm, Titanium Alloy (TAN), violet





496.721 Transpedicular Schanz Screw B 6.2 mm with dual core, length 180/35 mm, Titanium Alloy (TAN), dark blue





496.776 Transpedicular Schanz Screw B 6.2 mm with dual core, thread length 40 mm, with double thread, Titanium Alloy (TAN), dark blue



Implants


496.796 Transpedicular Schanz Screw B 7.0 mm with dual core, thread length 40 mm, with double thread, Titanium Alloy (TAN), green



496.930 Cross-Link Rod B 3.5 mm, length 40 mm, Titanium Alloy (TAN)




498.102 Rod B 6.0 mm, hard, length 50 mm, Pure Titanium







498.813 Cross-Link Clamp for Rods B 6.0 mm, preassembled, Titanium Alloy (TAN), dark blue

498.831 Fracture Clamp for Rods B 6.0 mm, low profile, Titanium Alloy (TAN), light blue

498.833 Fracture Clamp for Rods B 6.0 mm, for cranial end, Titanium Alloy (TAN), turquoise

498.911 Fixation Ring for Rods B 6.0 mm, Titanium Alloy (TAN), light blue

Implants


314.070 Screwdriver, hexagonal, small, 2.5 mm, with Groove

388.140 Socket Wrench 6.0 mm, with straight handle

388.363 Holding Sleeve with Catches, for No. 314.070

388.410 Spreader Forceps for Pedicle Screws, length 330 mm

388.422 Compression Forceps, length 335 mm, for Pedicle Screws

388.450 Holding Forceps for USS Rods B 3.5/4.5 mm, length 295 mm

Instruments


388.540 Pedicle Probe B 3.8 mm with Canevasit Handle, length 230 mm, for Pedicle Screws B 5.0 to 7.0 mm

388.550 Pedicle Awl B 4.0 mm with Canevasit Handle, length 230 mm, for Pedicle Screws B 5.0 to 7.0 mm

388.750 USS Rod Cutting and Bending Device

388.931 USS Reduction Sleeve, for Nos. 296.750 and 496.750

388.932 USS Nut, knurled, for No. 388.931

391.771 Bolt Cutting Head B 5.0 mm, long, cutting height 2 mm, for Nos. 391.780 and 391.790

Instruments


391.780 Handle B 13.0 mm for Bolt Cutting Head, length 455 mm

391.790 Handle B 24.0 mm for Bolt Cutting Head, length 455 mm

393.100 Universal Chuck with T-Handle

394.570 Cancellous Bone Impactor, straight

394.701 Socket Wrench B 11.0 mm, cannulated, length 300 mm, for USS Fracture Clamps

395.380 T-Handle for Steinmann Pins and Schanz Screws


Bibliography

Aebi M, Thalgott JS, Webb JK (1998) AO ASIF Principles in Spine Surgery. Springer, Berlin Heidelberg New York, 107–122

Aebi M, Etter C, Kehl T, Thalgott J (1989) The Internal Skele-tal Fixation System. A New Treatment of Thoraco-Lumbar Fractures and Other Spinal Disorders. Clin Orthop 227: 30–43

Aebi M, Etter C, Kehl T, Thalgott J (1987) Stabilization of the Lower Thoracic and Lumbar Spine with the Internal Spine Skeletal Fixation System. Indications, Techniques, and first Results of Treatment. Spine, vol 12: 544–551

Benson DR, Borkus JK, Montesano PK, Sutherland TB, Mc-Lain RF (1992) Unstable Thoraco-Lumbar and Lumbar Burst Frac tures Treated with the AO Fixateur Interne. J Spinal Disord, vol 5, no 3: 335–343

Boss N, Marchesi D, Aebi M (1992) Survivorship Analysis of Pedicular Fixation Systems in the Treatment of Degenerative Disorders of the Lumbar Spine: A Comparison of Cotrel- Dubousset Instrumentation and the AO Internal Fixator. J Spinal Disord, vol 5, no 4: 403–409

Crawford RJ, Askin GN (1994) Fixation of Thoracolumbar Fractures with the Dick Fixator: the Influence of Transpedicu-lar Bone Grafting. Eur Spine J 3: 45–51

Daniaux H (1986) Transpedikuläre Reposition und Spongiosa-plastik bei Wirbelkörperbrüchen der unteren Brust- und Lenden wirbelsäule. Unfallchirurgie 89: 197–213

Dick W (1992) Fixateur Interne. Spine, State of the Art Reviews, vol 6, no 1: 147–173

Dick W (1989) Internal Fixation of Thoracic and Lumbar Spine Fractures. Hans Huber Publishers, Toronto Lewiston NY Bern Stuttgart

Dick W, Kluger P, Magerl F, Wörsdörfer O, Zäch G (1985) A New Device for Internal Fixation of Thoraco-Lumbar and Lumbar Spine Fractures: The ”Fixateur Interne“. Paraplegia 23: 225–232

Esses SI (1989) The AO Spinal Internal Fixator. Spine, vol 14: 373–378

Esses SI, Botsford DJ, Wright T, Bednar D, Bailay S (1991) Operative Treatment of Spinal Fractures with the AO Internal Fixator. Spine, vol 16, no 3S: S146–S150

Krag MH (1991) Biomechanics of Thoraco-lumbar Spinal Fixation. Spine, vol 16, no 3S: S84–S99

Krödel A, Weindl B, Lehner W (1994) Die ventrale Kompres-sionsspondylodese mit Fixateur- interne-Instrumentation – eine biomechanische Untersuchung. Z Orthop 132: 67–74

Magerl F, Aebi M, Gertzbein SD, Harms J, Nazarian S (1994) A Comprehensive Classification of Thoracic and Lumbar Inju-ries. Eur Spine J 3: 184–201

Marchesi DG, Thalgott JS, Aebi M (1991) Application and Results of the AO Internal Fixation System in Non-traumatic Indications. Spine, vol 16, no 3S: S162–S169

Wawro W, Konrad L, Aebi M (1994) Die monosegmentale Montage des Fixateur interne bei der Behandlung von thora-kolumbalen Wirbelfrakturen. Unfall chirurgie 97: 114–120

Wittenberg RH, Shea S, Edwards WT, Swartz DE, White AA, Hayes WC (1992) A Biomechanical Study of the Fatigue Characteristics of Thoraco-Lumbar Fixation Implants in a Calf Spine Model. Spine, vol 17, no 6S: S121–S128

Yamagata M, Kitahara H, Minami S, Takahashi K, Isobe K, Moriya H, Tamaki T (1992) Mechanical Stability of the Pedicle Screw Fixation Systems for the Lumbar Spine. Spine, vol 17, no 3S: S51–S54

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Not all products are currently available in all markets.

This publication is not intended for distribution in the USA.

All surgical techniques are available as PDF files at www.depuysynthes.com/ifu ©

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