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.