Stenosis is the narrowing of the spinal canal. Typically, the tunnels in vertebrae are quite spacious and much larger than the spinal cord and nerves that pass through them.
Each lumbar vertebra has three tunnels that can be affected by stenosis. The large tunnel in the middle of the vertebra is where the spinal cord and all of the spinal nerves are contained. A much smaller tunnel is on each side of the vertebra, where the individual nerves exit the spine. Narrowing of any of these tunnels can result in pressure on the spinal cord or spinal nerves.
Causes of Lumbar Spinal Stenosis
Some patients are genetically programmed to have smaller sized tunnels in the spine, predisposing them to develop spinal stenosis. Arthritic changes such as bone spurs, thickened ligaments, joint laxity and disc bulges can also cause stenosis, as can disc herniations or fractures.
Symptoms of Lumbar Spinal Stenosis
Patients with lumbar spinal stenosis typically experience lower back pain along with pain in the buttocks and legs. This usually affects patients more when they are standing or walking, and pain is often relieved when sitting or lying. Many patients report that the decrease in their ability to walk is the most bothersome part of the condition. Some have found that leaning forward, such as using a cart while shopping, helps to ease pain.
Other conditions such as poor blood circulation to the legs, diabetic neuropathy, and hip or knee arthritis have very similar symptoms to spinal stenosis.
Treatment of Lumbar Spinal Stenosis
Conservative treatments such as over-the-counter anti-inflammatory medication, physical therapy, and chiropractic care may result in partial relief of symptoms. For more severe symptoms, a series of steroid injections into the spine may calm the inflammation of the nerves and give temporary relief of the buttock and leg pain. Though these treatments may help the patient cope with the symptoms for several years, they have little effect on the natural progression of the disease, which is slowly degenerative.
Patients who are no longer able to tolerate the symptoms or have symptoms that interfere with everyday activities despite conservative treatments may be good candidates for a decompression type of spine surgery. The procedure typically performed is called a laminectomy. Some patients may require a lumbar fusion in addition to the laminectomy if there is too much joint laxity from the arthritic changes in the spine.
A decompression operation for spinal stenosis is about 80% effective in reducing buttock and leg symptoms, including the ability to stand and walk. Though there may be some reduction in low back pain, a laminectomy is much less predictable for the treatment of isolated back pain without symptoms in the buttocks or legs.