Spinal stenosis is a disorder in which the spinal canal narrows, leading to back pain and leg pain that comes and goes with activities such as walking. Although stenosis can occur in all areas of the spine, it most commonly affects the lumbar (lower) spine. However when spinal stenosis occurs in the back, it produces pressure on the spinal cord and may affect gait, bowel and bladder function. Thus spinal stenosis almost always requires spinal treatment. Since it most commonly results from a combination of aging and degeneration of the spine, stenosis usually affects people over 60 years of age. However, the disorder also occurs in younger people who have abnormally small spinal canals from birth.
Since spinal stenosis gives the spinal cord and nerves less room to move, they can become irritated and inflamed. Stenosis in the lower back can cause pain in both the back and legs, with the pain becoming worse when walking or standing for a prolonged period of time. Rest, which takes pressure off the nerve roots, may ease or even eliminate these symptoms.
Anything that narrows the spinal canal makes the spinal cord and spinal nerves vulnerable to pressure that may cause irritation and inflammation. Conditions that can narrow the spinal canal include wear and tear of the joints (degeneration), bulging or herniated discs, arthritis, swollen ligaments, facet joint enlargement (hypertrophy), bone spurs and spondylolisthesis. Rarely, spinal infection or tumors may mimic the symptoms of spinal stenosis. Any activities that increase the demand for blood flow cause the blood vessels to swell and enlarge. If the spinal canal has narrowed, it may leave little or no room for the blood vessels to enlarge. This makes it difficult for blood flow to increase, which causes pain. Weakness also results because the nerves cannot get enough oxygen (which is carried through the bloodstream) to meet the demand. People who have a narrow spinal canal from birth are at risk for developing stenosis earlier in life because even minor crowding inside the spinal canal can cause pain.
The most common diagnostic tests used to determine the presence of spinal stenosis are X-rays of the lower back and an MRI. In some cases, a CT scan may be ordered, either in addition to an MRI or instead of one.
WHERE DOES IT HURT?
Spinal stenosis is a slowly progressive back problem that in its early stages may respond to conservative care, such as pain medications and rest. Your doctor may also recommend physical therapy and/or an epidural steroid injection (ESI). In some cases, simply bending over can relieve the back and leg pain caused by spinal stenosis, because bending over enlarges the spinal canal so that the blood flow to the spinal nerves increases.
Spinal stenosis may worsen over time, necessitating surgery. The main goal of any surgical procedure is to remove the pressure on the nerve roots in the lumbar spinal canal. The surgeon will therefore enlarge the tube of the spinal canal and remove any bone spurs that are pushing into the nerve roots. This procedure is called a decompression, or a decompressive laminectomy, of the lumbar spine.
The surgeon may also have to remove a portion of the facet joints. The lamina and facet joints normally provide stability in the spine. Removal of either or both can cause the spine to become loose and unstable. If this occurs, doctors will restabilize the spine by including spinal fusion as part of the procedure. In most cases, surgery to correct spinal stenosis is appropriate only when the patient regards the pain as unbearable.
In the cervical spine, stenosis may sometimes require decompression from the front, back or both front and back of the spine depending on the severity of the stenosis.