Occipital calvarial bone graft in posterior occipitocervical fusion

Abstract

Study design: Dorsal occipitocervical fusion is associated with a high rate of fusion failure and requires an additional surgical site for donor bone graft harvesting. In this series, an autologous occipital calvarial bone graft obtained from the same occipitocervical incision with contoured metal loops was used in 25 adults to achieve craniovertebral stabilization and fusion.

Objectives: To study the use of autologous occipital calvarial bone grafts in occipitocervical fusion.

Summary of background data: Cranial bone grafts have been used successfully in craniofacial reconstruction with good long-term results. In the plastic surgery literature, there are claims that membranous bone grafts are superior to endochondral bone grafts in fusions because of decreased resorption. In recent studies, results have shown successful use of calvarial bone in fusing the upper cervical spine in children. The use of autologous occipital bone in posterior occipitocervical fusions avoids many of the problems associated with traditional donor sites and provides a sufficient quantity of good quality bone for the fusion. This is especially true in the fragile rheumatoid arthritis patient with cranial cervical instability.

Method: Split-thickness, autologous calvarial bone grafts with contoured loop and cable instrumentation were used for posterior occipitocervical stabilization and fusion in 25 patients, most of whom had rheumatoid arthritis. The calvarial bone graft was harvested from the occipital skull, using a microair impactor, and was secured next to the loop construct. After surgery, all patients were immobilized with external orthoses.

Results: None of the patients had hardware failure or complications from the occipital graft procurement. In 22 patients, good alignment, stability, and bony fusion were shown on radiographs.

Conclusions: Occipital calvarial bone graft appears to work as well as other autologous corticocancellous bone grafts routinely used in posterior occipitocervical fusions.