[Failure of surgery for lumbar spinal stenosis. Apropos of 38 cases verified by computed x-ray tomography].

The authors have reviewed 38 patients who had been operated on for lumbar spinal stenosis. All were studied by C.A.T. scanning. In 28 instances the results were satisfactory. In 22, the scan was normal but in 4 a central stenosis remained and in two a lateral stenosis. Despite the fact that the patients were asymptomatic, the authors consider that they may be subject to recurrence in future. The results were fair or poor with persistent neurological claudication or root impairment. In 8 instances the scanning was performed of the whole length of the lumbar spine and showed thick remaining central stenoses, two of them at a level higher than the level of the surgical procedure. These cases had not been diagnosed by pre-operative myelography. In two instances the root was still compressed despite total laminectomy and joint resection. In two instances the post-operative scan did not reveal the cause of the failure but the whole length of the lumbar spine had not been examined. It is concluded that total laminectomy and joint excision is the safer surgical procedure in cases of root impairment but the procedure may lead to instability in instances where the lumbar spine is still mobile. This may have to be treated by arthrodesis. Tomodensitometry is of considerable help but is not the only fact on which surgical procedures should be based.