Treatment of cervical spondylotic myelopathy by enlargement of the spinal canal anteriorly, followed by arthrodesis.

Thirty-seven patients who had enlargement of the spinal canal anteriorly and stabilization of the spine for cervical spondylotic myelopathy were followed for an average of forty-nine months (range, twenty-eight to seventy months). Myelography and computed tomographic myelography were performed preoperatively on all patients to determine the location and features of the areas of decompression. The canal was enlarged by discectomy; by subtotal corpectomy and removal of the anteromedial parts of the pedicles; or by removal of osteophytes or of the posterior longitudinal ligament, or both. Partial corpectomy and interbody arthrodesis was performed in nine patients; subtotal corpectomy, including removal of the posterior parts of the vertebral bodies and of the posterior longitudinal ligament, and strut bone-grafting, in fifteen patients; and subtotal corpectomy, with detachment of the remaining thin posterior parts of the vertebral bodies and of the posterior longitudinal ligament, and strut bone-grafting, in thirteen patients. Postoperatively, radiographic examinations, including myelography and computed tomographic myelography, were performed for thirty-six patients and magnetic resonance imaging, for twenty-eight. A satisfactory neurological result was obtained in twenty-nine patients. Atrophy of the spinal cord, as seen on preoperative computed-tomographic myelograms, was predictive of an unsatisfactory result of the decompression, as was weakness of the peroneal muscles. All but one of the thirty-seven patients had improved walking ability at the most recent follow-up examination: seventeen patients improved by 1 point; fourteen, by 2 points; four, by 3 points; and one, by 4 points. The remaining patient reverted to the preoperative status after an initial improvement. The ability to walk at the interim examinations was compared with that at the most recent examination; three patients had continuing improvement, while three others had deterioration. The main cause of deterioration was new spondylotic changes associated with stenosis of the spinal canal, occurring at the level of the disc just cephalad to the fused levels. We concluded that anterior decompression followed by a secure arthrodesis should be an extensive procedure for patients who have cervical spondylotic myelopathy, as determined preoperatively from a myelogram or computed tomographic myelogram. Excision of the vertebral bodies should also be wide and should include the anteromedial parts of the pedicles. The third or fourth cervical vertebra should be included in the arthrodesis prophylactically in patients who have stenosis of the spinal canal when either of these vertebrae is adjacent to the level of fusion.