1. SURGICAL TECHNIQUES IN CERVICAL SPINE STABILIZATION Manish Vaish

2. C1 C2 Dens Zygapophyseal joints The articulation of the ATLANTOAXIAL JOINT between the atlas (C1) and the axis (C2) has a range of motion in the transverse plane for rotation. The DENS of C2 acts as a pivot point for the rotation of C1. The articulating surfaces of the two vertebrae form the ZYGAPOPHYSEAL (FACET) JOINTS that allow flexion-extension, side bending, and rotational movements. 3. Axial View Transverse ProcessBody Sulcus for Spinal Nerve Lateral Mass Lamina Pedicle Superior Articular Facet Vertebral Foramen Bifid Spinous Process Transverse Foramen 4. Sulcus for Spinal Nerve Uncinate Process Uncovertebral Joint (Joint of Luschka) Anterior View 5. 45 to the axial plane In the cervical region, the facet joints are flat and oriented 45 to the horizontal. This means that the cervical region has a significant range of motion in the six degrees of freedom. 6. 14year/male After RTA in FEB 2011 and presented to FHN in May 2011 with Pain in neck movements which progressed to inability to move neck Quadriparesis 7. 35 years/male H/O RTA admitted with Painful neck movements Difficulty in walking 8. 58 years male K/C/O Rheumatoid arthritis for 13 years Quadriparesis 20 days Operated twice(2007,2009) with C1 posterior arch excision with C0 C2 fusion and revision done with C3 C4 laminectomy 9. Atlantoaxial dislocation reducible irreducible Type II # Odontoid screw Magerl or Various C1-2 screw fixation Occiput-Cervical fusion Anterior compression Anterior decompression No compression C1 laminectomy fragile C1 lamina Failed C1-2 fusion Occipitalised atlas C1 post elements # 10. Magerl transarticular Screws C1 lateral mass screw C2 pars screw C2 pedicle screw C2 laminar screws Hybrid wire and screw fixation 11. Source: Medscape, MyAANS 12. Entry point in line with the medial edge of the lamina origin Direction of screws 13. The average length of screw adjacent to the lamina is 1cm and within the lateral massis upto 2 cm 14. The Harms technique The entry point for placement of a C2 pedicle screw was 2 mm from the medial border and 5 mm from the caudal border of the C2 articular process. The trajectory is at an angle of 20 to 30 degrees cranially, and in the transversal plane, the screws were directed medially at an angle of 20 to 25 degrees 15. Lateral mass 25 Trans Artricular 45 Pedicle 1mm medial 1-2 mm cephalad 16. CT Scan Madawi AA, Casey AT, Solanki GA, Tuite G, Veres R, Crockard HA : Radiological and anatomical evaluation of the atlantoaxial transarticular screw fixation technique. J Neurosurg 86 : 961-968, 1997 17. Image guided spinal surgery C1-C2 TRANSARTICULAR SCREWS 18. LEFT C1-C2 RIGHT C1-C2 ENTRY POINT TARGET POINT Image guided spinal surgery 19. Image guided spinal surgery C1-C2 TRANSARTICULAR SCREWS 20. Destruction of C1 lateral mass/ fracture or destroyed C2 pars interarticularis Large Vertebral Artery groove Irreducible subluxation Aberrant Vertebral Artery Occipitalized atlas (relative) Following transoral odontoidectomy (relative) 21. Mal position of screws Implant failure Spinal cord / dura/ 12th injury Vertebral Artery injury 22. A C2 pars screw is placed in a trajectory similar to that of a C1-C2 transarticular screw except that it is much shorter Screw length is typically 16 mm, stopping short of the transverse foramen . 23. Because the trajectory of this technique is more superior and medial than the transarticular screw fixation, potential risk of vertebral artery injury is lower Intraoperative reduction of the C1-C2 complex can be accomplished by direct manipulation of C1 and C2. The polyaxial screws can be joined to the occiput and subaxial cervical spine. Temporary fixation of the C1-C2 complex is possible, because this technique does not damage the C1-C2 facet joint 24. Wright NM : Posterior C2 fixation using bilateral, crossing C2 laminar screws : case series and technical note. J Spinal Disord Tech 17 :158-162, 2004 Leonard JR, Wright NM : Pediatric atlantoaxial fixation with bilateral, crossing C-2 translaminar screws. Technical note. J Neurosurg 104 : 59-63, 2006 25. Entry point spine-lamina junction Directed towards lamina-facet junction Average 30mm long 26. Roy-Camille Variations in entry point, trajectory An technique lowest risk of nerve root injury screw =15mm 27. 3 column fixation (A) Superior to lateral mass screws (biomechanical) Preop CT: bones, verts, nn. Enter lateral to center of facet, close to post margin of superior articular surface Point of entry decorticated with high speed drill Angles vary (B, C) 28. These three techniques provided equivalent stability to the C1 to C2 complex in flexion- extension and axial rotation C1 lateral mass-C2 laminar screw technique provided slightly less stiffness than other techniques in lateral bending pedicle screws provide the strongest fixation for both initial and salvage applications. If they should fail, lamina screws appear to provide stronger and more reproducible fixation than pars screws. 29. Dissection is carried to the tips of the transverse processes Attention is given to the preservation of the most cephalad facet capsule while all other soft tissue is removed from the facet The peri-spinal musculature is retracted for intra-canal work Appropriate laminotomies and/or laminectomy may be performed Attention is now directed toward instrumentation of the spine 30. The anatomy of the C2 is highly variable. It is essential to routinely perform a CT an individually evaluate every screw tract to provide the safest option. Knowledge of the various techniques described are useful when dealing with instability in the craniovertebral junction 31. THANKS VERY MUCH