Degenerative lumbar spondylolisthesis. II. Surgical treatment.

The authors analyze the results of operative treatment in 32 cases of degenerative spondylolisthesis with various degrees of compression of the nervous structures. Five types of surgery were performed: unilateral laminotomy; bilateral laminotomy with or without transverse process fusion; bilateral laminectomy with or without spinal fusion; and laminectomy, spinal fusion, and interspinous wiring. Satisfactory results were achieved in 84% of the cases. Seventy-six percent of the patients had further vertebral displacement, and 81% showed varying degrees of articular process regeneration more than two years after surgery; these findings concern both patients who had been treated with spinal fusion and those who had not. Bilateral laminotomy is indicated in patients with isolated nerve root canal stenosis; as the olisthesis is mild and lateral flexion-extension radiographs show no vertebral hypermobility, spinal fusion is not necessary. When central spinal canal stenosis is present, bilateral laminectomy, extensive lateral decompression, and spinal fusion are recommended. Interspinous wiring may be useful for immediate vertebral stabilization.