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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.
However, some patients are genetically programmed to have smaller size tunnels
in the spine, predisposing them to develop symptoms from spinal stenosis. Arthritic
changes such as bone spurs, thickened ligaments, joint laxity and disc bulges
can cause stenosis, as can disc herniations or fractures.
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.
Symptoms
Patients with lumbar spinal stenosis typically have 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.
Treatments
Conservative treatments such as over-the-counter anti-inflammatory medication,
physical therapy and chiropractic care may give 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 symptoms. Though these treatments may help the patient
cope with the symptoms for several years, they have little effect on the natural
history of the disease, which is slow progression.
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 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.
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