Occipital bone graft for atlantoaxial fusion

Instability of the atlantoaxial segment is frequently encountered in neurosurgical practice. Numerous fusion techniques have been employed at this level. Most commonly, arthrodesis is achieved through bone and wire techniques. We have employed the use of suboccipital bone in lieu of iliac crest autograft in order to avoid the significant morbidity associated with iliac crest graft harvest.

Twenty one patients suffering instability from various etiologies underwent C1-C2 fusion at our institution using occipital bone graft and wire fixation. A small craniectomy was performed near the foramen magnum, and the bone graft was notched and secured in place using wire fixation. Patients were placed in a Philadelphia or Aspen collar for 6-12 weeks postoperatively, and flexion/extension plain film of the cervical spine were used to evaluate fusion.

Long term follow up was available on all patients (mean 32 months, range 12-48 months). Fusion was achieved in 81% of patients within 12 weeks. Specifically, 71% (5/7) of rheumatoid patients were successfully fused. All patients with traumatic C1-C2 instability were fused. No complications were associated with the harvest of the occipital bone.

The results of fusion via this technique are comparable to other reported series of C1-C2 fusion. Additionally, the complications associated with iliac crest graft harvest were avoided by the use of occipital bone graft. Occipital bone appears to be a suitable bone graft substance for fusion of the C1-C2 level.