Table of contents. Introduction. Features and Benefits 2. AO Principles 4. Indications and Contraindiactions 5. Implants 6. Productinformation

Transcription

1 Technique Guide CerviFix. Modular tension band system for posterior fixation of the occipito - cervical spine, upper and lower cervical spine, and upper thoracic spine.

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3 Table of contents Introduction Features and Benefits 2 AO Principles 4 Indications and Contraindiactions 5 Productinformation Implants 6 Instruments 9 Set 11 Surgical Technique Occipito-Cervical Stabilization 12 Fixation of Lower Cervical Spine 20 Bibliography 25 Image intensifier control Warning This description alone does not provide sufficient background for direct use of the instrument set. Instruction by a surgeon experienced in handling these instruments is highly recommended. Reprocessing, Care and Maintenance of Synthes Instruments For general guidelines, function control and dismantling of multi-part instruments, please refer to: Synthes 1

4 Features and Benefits CerviFix is a modular tension band system for posterior fixation of the occipitocervical spine, upper and lower cervical spine, and upper thoracic spine (T2). A choice of clamps are fixed on a rod by means of set screws. Bone screws can be optimally positioned through the clamps in the desired direction at each level. Individual screw placement Freedom of clamp positioning on the rod lets you choose the anatomically optimal screw entry sites. 2 Synthes CerviFix Technique Guide

5 Secure screw setting Three different clamp angles, according to Magerl trajectories, allow deep, secure anchorage in the lateral masses of C2 and C3 C7, and in the pedicles of T1 T2. C2 C3 C7 T1 T2 Clever solutions Lateral rods allow maximum space for extensive bone grafting. Lamina bridging for dura protection after laminectomy. Lamina hooks for osteoporotic vertebrae. Synthes 3

6 AO Principles In 1958, the Association for the Study of Internal Fixation (AO) formulated four basic principles 1, which have become the guidelines for internal fixation. They are: Anatomical reduction Stable internal fixation Preservation of blood supply Early, active pain-free mobilization The fundamental aims of fracture treatment in the limbs and fusion of the spine are the same. A specific goal in the spine is returning as much function as possible to the injured neural elements. AO Principles as applied to the spine 2 Anatomical reduction 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 pain-free 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 Müller ME, Allgöwer M, Schneider R, Willenegger H (1995) Manual of Internal Fixation. 3rd, exp. a. completely rev. ed Corr. 3rd printing. Berlin, Heidelberg, New York: Springer 2 Aebi M, Thalgott JS, Webb JK (1998) AO ASIF Principles in Spine Surgery. Berlin, Heidelberg, New York: Springer 4 Synthes CerviFix Technique Guide

7 Indications and Contra-indications Indications Occipitocervical and upper cervical spine instabilities: Rheumatoid arthritis Anomalies Posttraumatic conditions Tumours Infections Instabilities in the lower cervical spine: Posttraumatic instabilities Tumours Iatrogenic instabilities following laminectomy Degenerative and painful posttraumatic conditions in the lower cervical spine Anterior fusions requiring additional posterior stabilization Contra-indications Spinal destruction accompanied by loss of ventral support (caused by tumours, fractures and infections) results in major instability of the cervical spine and upper thoracic spine. In this situation, stabilization with CerviFix only is not sufficient. Additional anterior stabilization is crucial. Severe osteoporosis Synthes 5

8 Implants Cortex Screws 3.5 mm Titanium Alloy (TAN) Spherical head Core diameter 2.4mm Self-tapping Art. No. Length mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm mm 6 Synthes CerviFix Technique Guide

9 C2 Clamps (TAN) Art. No. Angulation Right Left C3/C7 Clamps (TAN) Art. No. Angulation Right Left Pedicle Clamp (TAN) Art. No. Angulation Neutral Lamina Clamps (TAN) Art. No. Angulation Right Left Hooks, Titanium Alloy (TAN) Art. No. Angulation Right, small Left, small Right, large Left, large Set Screw with Cone Art. No Synthes 7

10 Implants Rods 3.5 mm Available in lengths 80, 120 and 240 mm Titanium Alloy (TAN) / Pure Titanium (TiCP) Art. No. Length Material mm TAN mm TiCp mm TAN mm TiCp mm TiCP Occiput Rod 3.5 mm Available length 240 mm Pure Titanium (TiCp) Art. No Connecting Rods Available in lengths 300 and 500 mm Pure Titanium (TiCp) Art. No. Length mm 3.5/5.0 mm mm 3.5/6.0 mm mm 3.5/5.0 mm mm 3.5/6.0 mm Parallel Connectors Titanium Alloy (TAN) Art. No CerviFix Parallel Connector, gold 3.5/3.5 mm Parallel Connector for USS Small Stature/Paediatric, light blue, 3.5/5.0 mm CerviFix Parallel Connector 3.5/6.0 mm 8 Synthes CerviFix Technique Guide

11 Instruments Handle for Drill Guide Inserts, for Nos , and Drill Guide Insert 3.5, with Knurled Nut, for No Drill Guide Insert 2.7, calibrated, with Knurled Nut, for Nos and T-Handle with Quick Coupling Drill Bit 2.5 mm, length 160/135 mm, 3-flute, for Quick Coupling Tap for Cortex Screws 3.5 mm Depth Gauge for Screws 2.7 to 4.0 mm, measuring range up to 60 mm For depth measurement through the plate Synthes 9

12 Instruments Screwdriver, hexagonal, small, self-holding Trial Rod 3.5 mm Trial Rod 2.8 mm, length 240 mm, for CerviFix Occiput Trial Rod 3.5 mm Rod Cutter, for Rods 3.5 mm Bending Pliers for Rods 3.5 mm and Plates CerviFix Holding Forceps for Rods 3.5 mm 10 Synthes CerviFix Technique Guide

13 CerviFix Compression Forceps for Rods 3.5 mm Set Vario Case for CerviFix, with Lid, without Contents Synthes 11

14 Occipito-Cervical Stabilization Positioning The patient is placed in a prone position. Reduction Reduction of C1 on C2 is performed when indicated, using image intensification. Approach Subperiosteal exposure of occiput, posterior atlas ring, posterior elements of C2, spinous processes, vertebral arches, and articular masses of those lower cervical spine vertebrae to be included in the fusion. For a transarticular screw fixation of C1/C2, the isthmus of C2 must be exposed on both sides. 1 Semispinalis capitis muscle 2 Semispinalis cervicis muscle 3 Superior oblique muscle of the head 4 Smaller straight muscle of the head 5 Greater straight muscle of the head 6 Inferior oblique muscle of the head 7 Posterior arch of the atlas 8 Zygapophyseal articulations 9 Vertebral artery 10 Occipital artery 11 Third occipital nerve 12 Greater occipital nerve 8 13 Suboccipital nerve Synthes CerviFix Technique Guide

15 1 Bending the rod Instruments Occiput Trial Rod 3.5 mm Bending Pliers for Rods 3.5 mm and Plates Rod Cutter, for Rods 3.5 mm Optional instruments Trial Rod 2.8 mm, length 240 mm, for CerviFix Trial Rod 3.5 mm Bend the template in such a way that its cranial end, adjacent to the midline, is situated just caudal to the protuberantia occipitalis externa, and that the rod passes over the lateral rims of the articular processes of C2, C3, etc. Bend and cut the occipital rod according to the template and confirm the correct fit in situ. Note: Titanium rods are weakened when being bent back and forth. Synthes 13

16 Occipitocervical Stabilization 2 Instrumenting C1/C2 Instruments T-Handle with Quick Coupling Drill Bit 2.5 mm, length 160/135 mm, 3-flute, for Quick Coupling Handle for Drill Guide Inserts, for Nos , and Drill Guide Insert 2.7, with calibrated with Knurled Nut, for Nos and If necessary, reduce a C1/C2 dislocation under image intensification and drill the screw holes on both sides for a trans - articular C1/C2 fusion using the Magerl technique. In order to provisionally stabilize C1/C2, leave the drill bit in situ on one side while drilling and instrumenting the other side. 14 Synthes CerviFix Technique Guide

17 3 Instrumenting the most caudal vertebra Instruments T-Handle with Quick Coupling Drill Bit 2.5 mm, length 160/135 mm, 3-flute, for Quick Coupling Handle for Drill Guide Inserts, for Nos , and Drill Guide Insert 2.7, with calibrated with Knurled Nut, for Nos and Tap for Cortex Screws 3.5 mm, length 180/110 mm Drill the screw hole in the most caudal vertebra to be stabilized using the Magerl technique. Tap the near cortex only. Synthes 15

18 Occipitocervical Stabilization 4 Provisional clamp mounting Instruments Screwdriver, hexagonal, small, self-holding CerviFix Holding Forceps for Rods 3.5 mm Provisionally mount and slightly fasten all necessary clamps on the rod. 5 C1/C2 screw insertion Instruments Depth Gauge for Screws 2.7 to 4.0 mm, measuring range up to 60 mm Tap for Cortex Screws 3.5 mm, length 180/110 mm T-Handle with Quick Coupling Screwdriver, hexagonal, small, self-holding Measure the length of the C1/C2 transarticular screw through its corresponding clamp. Tap and insert the screw. Choose a screw that is a little too short rather than one that is too long. 16 Synthes CerviFix Technique Guide

19 6 Occipital screw insertion Instruments T-Handle with Quick Coupling Drill Bit 2.5 mm, length 160/135 mm, 3-flute, for Quick Coupling Handle for Drill Guide Inserts, for Nos , and Drill Guide Insert 2.7, with calibrated with Knurled Nut, for Nos and Depth Gauge for Screws 2.7 to 4.0 mm, measuring range up to 60 mm Tap for Cortex Screws 3.5 mm, length 180/110 mm Screwdriver, hexagonal, small, self-holding Drill three occipital screw holes, measure the screw length through the plate. Tap and insert the screws. 7 Caudal screw insertion Instruments Depth Gauge for Screws 2.7 to 4.0 mm, measuring range up to 60 mm T-Handle with Quick Coupling Screwdriver, hexagonal, small, self-holding Insert the most caudal screw of the assembly. Synthes 17

20 Occipito-Cervical Stabilization 8 Intermediate screw insertionn Instruments T-Handle with Quick Coupling Drill Bit 2.5 mm, length 160/135 mm, 3-flute, for Quick Coupling Handle for Drill Guide Inserts, for Nos , and Drill Guide Insert 2.7, with calibrated with Knurled Nut, for Nos and Depth Gauge for Screws 2.7 to 4.0 mm, measuring range up to 60 mm Tap for Cortex Screws 3.5 mm, length 180/110 mm Screwdriver, hexagonal, small, self-holding Through the corresponding clamps, drill the screw holes for the intermediate clamps between C2 and the most caudal element. Tap and insert the screws. 18 Synthes CerviFix Technique Guide

21 9 Insert second occiput rod accordingly Repeat steps 1 to Bone grafting Apply cancellous bone graft. Between the occiput and the spinous process of C2, a corticocancellous bone graft is inserted acting as a buttress. Postoperative care A Philadelphia collar is worn for a period of 12 weeks. It may be removed for daily care and while resting. If no cancellous bone graft has been applied (for tumour cases only, when bone cement is used!), an orthosis must be worn for life. Synthes 19

22 Fixation of Lower Cervical Spine Positioning The patient is placed in a prone position. Approach Perform a midline incision, subperiosteally expose the spinal processes, laminae, and articular masses of the vertebrae to be included in the fusion. 1 Bending the rod Instruments Trial Rod 3.5 mm Bending Pliers for Rods 3.5 mm and Plates Rod Cutter, for Rods 3.5 mm Optional instruments Trial Rod 2.8 mm, length 240 mm, for CerviFix Measure the rod length, cut and slightly contour the rod in lordosis. Note: Titanium rods are weakened when being bent back and forth. 20 Synthes CerviFix Technique Guide

23 2 Instrumenting the most cranial and most caudal vertebrae Instruments T-Handle with Quick Coupling Drill Bit 2.5 mm, length 160/135 mm, 3-flute, for Quick Coupling Handle for Drill Guide Inserts, for Nos , and Drill Guide Insert 2.7, with calibrated with Knurled Nut, for Nos and Tap for Cortex Screws 3.5 mm, length 180/110 mm Drill the screw holes for the most cranial and most caudal clamps using the Magerl technique. Tap the near cortex only. 3 Clamp mounting Instruments Screwdriver, hexagonal, small, self-holding CerviFix Holding Forceps for Rods 3.5 mm Mount all the planned clamps on the rod. Synthes 21

24 Fixation of Lower Cervical Spine 4 Caudal and cranial screw insertion Instruments Depth Gauge for Screws 2.7 to 4.0 mm, measuring range up to 60 mm Tap for Cortex Screws 3.5 mm, length 180/110 mm T-Handle with Quick Coupling Screwdriver, hexagonal, small, self-holding Optional instruments CerviFix Compression Forceps for Rods 3.5 mm Measure the screw length through the clamps. Tap the near cortex and insert the most caudal screw, then the most cranial. If you desire slight posterior compression (lordosis), bring the cranial clamp closer to the caudal one and fix it to the rod. The cranial screw will cause intersegmental compression and lordosis when tightened. 22 Synthes CerviFix Technique Guide

25 5 Instrumenting the intermediate vertebrae Instruments Screwdriver, hexagonal, small, self-holding T-Handle with Quick Coupling Drill Bit 2.5 mm, length 160/135 mm, 3-flute, for Quick Coupling Handle for Drill Guide Inserts, for Nos , and Drill Guide Insert 2.7, with calibrated with Knurled Nut, for Nos and Depth Gauge for Screws 2.7 to 4.0 mm, measuring range up to 60 mm Tap for Cortex Screws 3.5 mm, length 180/110 mm Screwdriver, hexagonal, small, self-holding Drill the intermediate screw holes through the clamps. Tap and screw in the corresponding screws. 6 Insert second occiput rod accordingly Repeat steps 1 to 5. Synthes 23

26 Fixation of Lower Cervical Spine 7 Mounting a laminar substitute Instruments Screwdriver, hexagonal, small, self-holding CerviFix Holding Forceps for Rods 3.5 mm To increase rotational stability, to protect the dura after laminectomies, and to suture the musculature, mount a laminar substitute. 8 Bone grafting Apply cancellous bone graft on the articular processes. 9 Wound closure Close the wound. The musculature may be sutured to the laminar substitute. Postoperative care Immobilization of the cervical spine for eight weeks in a Philadelphia collar which can be removed for resting. 24 Synthes CerviFix Technique Guide

27 Bibliography Jeanneret B, Magerl F, Ward EH, Ward JC (1991) Posterior Stabilization of the Cervical Spine with Hook Plates. Spine 16 (3S): Jeanneret B (1992) Posterior Fusion of the Cervical Spine. Spine: State of the Art Reviews 6 (3) Jeanneret B (1994) Posterior Transarticular Screw Fixation of C1 C2. Techniques in Orthopaedics 9 (1) 1994 Jeanneret B (1996) AO Posterior Rod System of the Cervical Spine: a new implant allowing optimal screw insertion. Eur Spine J 5 (5): Sasso RC, Jeanneret B, Fischer K, Magerl F (1994) Occipitocervical Fusion with Posterior Plate and Screw Instrumentation: a long-term follow-up study. Spine 19 (20): Müller ME, Allgöwer M, Schneider R, Willenegger H (1995) Manual of Internal Fixation. 3rd, expanded and completely revised ed Berlin, Heidelberg, New York: Springer

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