A New Technique for the Surgical Treatment of Atlantoaxial Instability: C1 Lateral Mass and C2-3 Transfacet Screwing

Özet

Atlantoaxial instability is a special entity that may be caused by many disorders such as trauma, tumor, arthritis, congenitalmalformation and infection. Atlantoaxial fixation is needed to provide stability, prevent neurological deficits and correct deformity.The aim of this report is to introduce an alternative technique for the treatment of atlantoaxial instability in patients who have vertebralartery anomaly, anomalous C2 or osteoporosis. C1-2-3 fixation was performed in a 50-year-old male patient with atlantoaxialinstability due to os odontoideum. C1 lateral masses were identified and screw placement was performed. C2 facet joints wereidentified bilaterally. The superior margin of the junction of pedicle and the lamina was used as the entry point and 3.5x22 mmscrews were inserted from C2 facet joint to the C3 facet joint in the mediolateral and craniocaudal direction under fluoroscopicguidance with caution. The posterior fixation screws were interconnected with two rods. Finally, autologous grafts were placedposterolaterally to encourage the fusion. The patient’s complaints were relieved after the surgery. C1-C2 instability was not seenin the postoperative radiological examinations. In the surgical treatment of C1-2 instability, our technique could help reduce thepossibility of vertebral artery injury in patients who have a vertebral artery course anomaly or when it is difficult to place C2 pediclescrews due to anomalous C2 pedicles and osteoporosis. High fusion rate could be achieved with this technique due to passingthrough the four cortical surfaces. No wire or allograft was required. Thus, the instrumentation cost could be reduced.