Lumbar Spinal Stenosis
(See also Evaluation of Neck and Back Pain.)
Spinal stenosis can be congenital or acquired. It may involve the cervical or lumbar spine. Acquired lumbar spinal stenosis (LSS) is a common cause of sciatica in middle-aged or elderly patients. The most common causes of LSS are osteoarthritis, degenerative disk disorders, spondylosis, and spondylolisthesis with compression of the cauda equina. Other causes include Paget disease of bone and ankylosing spondylitis.
Pain occurs in the buttocks, thighs, or calves during walking, running, climbing stairs, or even standing. This pain is referred to as neurogenic claudication. The pain is not relieved by standing still but by flexing the back or by sitting (although paresthesias may continue). Walking up hills is less painful than walking down because the back is slightly flexed. Patients may have pain, paresthesias, weakness, and diminished reflexes in the affected nerve root distribution. Rarely, sudden nerve rootlet compression resulting from LSS or a large disk herniation may cause cauda equina syndrome with distal leg paresis and sensory loss in and around the perineum and anus (saddle anesthesia), as well as bladder, bowel, and pudendal dysfunction; unlike in spinal cord injury, muscle tone and deep tendon reflexes are decreased in the legs.
Spinal stenosis is suspected based on characteristic symptoms. Diagnostic tests are the same as for sciatica. Calf symptoms may simulate those of intermittent vascular claudication. Claudication can be differentiated by relief with rest (not position change), skin atrophy, and abnormalities in pulses, capillary refill, and vascular tests.
Conservative treatments and indications for surgery are similar to those for sciatica.
Epidural corticosteroid injections sometimes provide transient relief. In symptomatic patients who are poor candidates for surgical intervention, the combination of epidural injections and flexion-based physical therapy can result in some symptomatic improvement.
For advanced spinal stenosis, surgery involves decompression of nerve root entrapment by vertebral canal and foraminal encroachments, which sometimes requires laminectomy at 2 or 3 levels plus foraminotomies and sometimes fusion surgery.
Spinal stability must be preserved. Spinal fusion may be indicated if there is instability or severe, well-localized arthritic changes in 1 or 2 vertebral interspaces; however, recent studies highlight the controversial nature of this approach (1, 2).
Försth P, Olafsson G, Carlsson T, et al: A randomized, controlled trial of fusion surgery for lumbar spinal stenosis. N Engl J Med 374:1413-1423, 2016. doi: 10.1056/NEJMoa1513721.
Ghogawala Z, Dziura J, Butler WE, et al: Laminectomy plus fusion versus laminectomy alone for lumbar spondylolisthesis. N Engl J Med 374:1424-1434, 2016. doi: 10.1056/NEJMoa1508788.