Cervical myelopathy and posterior atlanto-axial subluxation in patients with rheumatoid arthritis.

Posterior atlanto-axial subluxation, which is uncommon and usually is considered a benign condition, was associated with cervical myelopathy in four patients with rheumatoid arthritis. The cause of the myelopathy appeared to be posterior kinking of the spinal cord without demonstrable compression. Contrast-enhanced sagittal imaging or computerized tomographic sagittal reconstruction provided the best means of demonstrating the abnormal configuration of the spinal cord. Halo traction and occipitocervical fusion yielded satisfactory results in all four patients after follow-up of one to two years. We developed a method to provide rigid fixation of an occipitocervical fusion in which a corticocancellous iliac-bone graft was backed with metal mesh, wired in place, and reinforced with methacrylate.