Low risk for vertebral slipping after decompression with facet joint preserving technique for lumbar spinal stenosis.

The incidence and magnitude of vertebral slipping after decompression for central lumbar spinal stenosis were determined in a prospective study of 60 consecutive patients. Mean patient age was 64 (35-83) years, and 35 patients were men. In all cases, laminectomy was performed using a facet joint preserving undercutting technique. Plain radiographs were obtained before and 1 year after surgery. Vertebral slipping and disc degeneration were measured. Preoperative degenerative olisthesis was seen in 19 of the 60 patients. Further slipping had occurred in 6 of these patients by 1 year postoperatively. Of the remaining 41 patients, only 1 showed a postoperative slipping. Improvement concerning leg pain was reported by 45 patients, and there was no difference in patients with or without postoperative slipping. It is concluded that decompression with a facet joint preserving technique yielded a low risk for postoperative vertebral slipping. The risk for slip was higher in patients with preoperative degenerative olisthesis but was still less than 1/3. Vertebral slipping did not influence the outcome of the operation at 1 year. Our results do not support the routine use of spinal fusion in connection with decompression for lumbar spinal stenosis.