Degenerative spondylolisthesis is a condition in which breakdown of the cartilage between the vertebrae of the spine causes one vertebra to slip over the one below. This can result in narrowing of the spinal column (spinal stenosis), which can put pressure on the nerves, resulting in pain in the buttocks or legs with walking or standing. The condition generally occurs after age 50 and it affects six times as many women as men.

The management of degenerative spondylolisthesis with spinal stenosis is controversial, says James N. Weinstein, D.O., M.Sc., lead author and chairman of the Departments of Orthopaedics at Dartmouth-Hitchcock Medical Center and Dartmouth Medical School. Surgery is widely used, but its effectiveness in comparison with nonsurgical treatment had not been demonstrated in controlled clinical trials. The purpose of this arm of the SPORT trial was to make that comparison.

SPORT followed 601 patients diagnosed with degenerative spondylolisthesis and symptomatic spinal stenosis. Of those, 372 received a surgery called decompressive laminectomy, which involved removing bone and soft tissue to relieve pressure on the nerves.

The remaining 235 pursued nonoperative treatments such as physical therapy, steroid injections and analgesic medications. Two years after enrollment in the trial, patients in the nonoperative groups reported modest improvement in their condition; however, patients who had the surgery reported significantly reduced pain and improved function. Furthermore, for the surgery group, relief from symptoms came quickly; some reported significant improvement as early as six weeks after the procedure.