Epidural glucocorticoid injections have been used for some time as a temporizing treatment for the pain of lumbar stenosis but a randomized trial conducted by Friedly and colleagues found no difference in disability or leg pain 6 weeks after one or two such injections. Nevertheless, the procedure is still widely used and some patients report relief, which is difficult to separate from the natural course of the process. A series of cases of meningitis that resulted from contaminated drug obtained wide attention but is less likely to occur in the future. Various physical therapy maneuvers and exercises may be helpful in the short run but none has been validated in comparison to others.
Insofar as lumbar stenosis can cause a cauda equina syndrome, its differential diagnosis is also considered in Chap. 42 on diseases of the spinal cord.
Degenerative Osteoarthritis of the Spine
Chronic and recurring back pain caused by degenerative arthritic disease is among the most common disorders in general practice. It occurs in later life and may involve all or any part of the spine but is most prevalent in the cervical and lumbar regions. The pain is described as a stiffness that is centered in the affected part of the spine. It is increased initially by movement and is associated with limitation of motion but is often worse on arising in the morning. In contrast to the spinal claudicatory syndrome of lumbar stenosis, warming up and progressive mobilization make the pain better. There is a notable absence of systemic symptoms such as fatigue, malaise, or fever, and, more importantly, there are usually no features of radicular compression although vague aching may be felt in a sciatic distribution. In contrast to conventional lumbar root compression, the straight-leg raising tests do not elicit pain. The sitting position is usually comfortable, although stiffness and discomfort are accentuated when the erect posture is resumed.
The severity of the symptoms often bears little relation to the radiologic changes; pain may be present despite minimal radiographic findings; conversely, marked osteophytic overgrowth with spur formation, ridging, bridging of vertebrae, narrowing of disc spaces, subluxation of posterior joints on flexion, and air in the disc spaces can be seen in both symptomatic and asymptomatic persons.
This syndrome has been somewhat clarified in recent years but its definition remains imprecise. In one form, osteoarthritic degeneration of the facet joint gives rise to a focal parasagittal lumbar back pain, with variable tenderness over the joint but without signs of nerve root compression. The pain can be quite severe, worse at night, and prevent sleep if no comfortable position can be found. Nonsteroidal anti-inflammatory drugs are helpful. Some patients have discovered that they may obtain temporary relief from facet pain by forcefully twisting or stretching the back and creating an audible pop at the affected joint, comparable to chiropractic manipulation. Over time, they acquire a laxity of the supporting structures of the joint, which may actually perpetuate the problem.
The diagnosis is confirmed when the pain is relieved for a variable period by injection of the joint with local anesthetic. Often one is uncertain whether it was the analgesic effect on the joint or the infiltration of the region around the nerve root that has relieved the pain. Two controlled studies have suggested the procedure of corticosteroid injections into the facet joints is ineffective, both in the short and long term (Carette et al, 1991; Lilius et al). Notwithstanding these reports, we have found the injection of analgesics and steroids in and around the facet to be a useful temporizing measure in some patients. Epidural injections of steroids have no clear role in the treatment of this condition. If the diagnosis is established by local injection, many centers offer radiofrequency ablation of the small recurrent sensory nerves that innervate the joint as a means of permanent relief. This has met with some success, but has not been studied systematically.