Surgical treatment of atlantoaxial instability

Objective To summarize the effect of midline and lateral fixation for atlantoaxial instability. Methods Bone grafting and internal fixation were performed for the atlantoaxial instability in 68 patients with interlaminar or interspinous cable and clamp or atlas and axis vertebrae screw through the midline or lateral mass. Results Immediate rigid segmental stabilization was observed in all cases with no procedure-related morbidity or mortality. Forty-seven patients were followed up for 3 months -7 years （averaged 17 months）. Pain of neck was disappeared and the myodynamia of extremities was improved at different extents after operation. No internal fixation breakage or loosening or dislocation was observed on dynamic radiographs 3 months after operation. Stable osseous fusion or well-aligned fibrous union was found in 46 patients. Follow-up 1 year after operation found that the grafted bone was absorbed and 1 patient experienced surgical operation showed that the grafted bone was absorbed in 1 patient and fused 1 year after repair. Conclusion Atlantoaxial stability and grafted bone fusion can be achieved in most atlantoaxial instability patients with midline sublaminar cable techniques. Lateral fixation of C1 and C2 can be used as an adjuvant method of midline fixation techniques.