Direct Posterior Reduction and Fixation for the Treatment of Basilar Invagination With Atlantoaxial Dislocation

OBJECTIVE: To report the surgical technique and clinical results for the treatment of basilar invagination (BI) with atlantoaxial dislocation (AAD) by direct posterior reduction and fixation using intraoperative distraction between the occiput and C2 pedicle screws. METHODS: From May 2004 to June 2008, 29 patients who had BI with AAD were surgically treated in our department. Pre- and postoperative dynamic cervical x-rays, computed tomographic scans, and 3-dimensional reconstruction views were performed to assess the degree of dislocation. Ventral compression of the cervicomedullary junction was evaluated by magnetic resonance imaging. For all patients, reduction of the AAD was conducted by intraoperative distraction between the occiput and C2 pedicle screws using a direct posterior approach. RESULTS: Follow-up ranged from 6 to 50 months in 28 patients. Clinical symptoms improved in 26 patients (92.9%) and were stable in 2 patients (7.1%) without postoperative deterioration. Radiologically, complete or more than 50% reduction was achieved in 27 of 28 patients (96.4%). In 1 patient, the reduction was less than 50% because the direction of the facets on 1 side of the C1-C2 joint was vertically oriented, instead of horizontal. Overall, good decompression and bone fusion were shown on postoperative magnetic resonance imaging, computed tomography, or x-ray scans for all patients. There was 1 death in the series because of basilar artery thrombosis 1 week after the operation. CONCLUSION: The direct posterior distraction technique between occiput and C2 pedicle screws is an effective, simple, fast, and safe method for the treatment of BI with AAD. Transoral odontoidectomy and cervical traction for the treatment of BI with AAD should be reconsidered.