Spinal stenosis is a narrowing of spaces in the spine (backbone) that results in pressure on the spinal cord and/or nerve roots. This disorder usually involves the narrowing
of one or more of three areas of the spine: (1) the canal in the center of the column of bones (vertebral or spinal column) through which the spinal cord and nerve roots run, (2) the canals at the base or roots of nerves branching out from the spinal cord, or (3) the openings between vertebrae (bones of the spine) through which nerves leave the spine and go to other parts of the body.
Pressure on the lower part of the spinal cord or on nerve roots branching out from that area may give rise to pain or numbness in the legs. Pressure on the upper part of the spinal cord (that is, the neck area) may produce similar symptoms in the shoulders, or even the legs. (See figs. 1, 2 and 3.)
Spinal stenosis is most common in men and women over 50 years of age. Younger people who are born with a narrowing of the spinal canal or who suffer an injury to the spine may develop a stenosis.
Early narrowing of the spinal canal is often asymptomatic. However, if the narrowing places pressure on the spinal cord, cauda equina, or nerve roots, there may be a slow onset and progression of symptoms. Most often, people experience numbness, weakness, cramping, or general pain in the arms or legs. If the narrowed space within the spine is pushing on a nerve root, people may feel pain radiating down the leg (sciatica). Sitting or flexing the lower back should relieve symptoms.
Cauda equina syndrome is a severe, and very rare, form of spinal stenosis. It occurs due to compression of the cauda equina, and symptoms may include loss of control of the bowel, bladder, or sexual function and/or pain, weakness, or loss of feeling in one or both legs. Cauda equina syndrome is a serious condition requiring urgent medical attention.
A thorough medical history and physical exam often times along with imaging studies are necessary to confirm a diagnosis of spinal stenosis and rule out other similarly presenting conditions. X-rays may be used to look for signs of arthritis, injury, tumor or inherited problems. MRI is particularly sensitive for detecting damage or disease of soft tissues, such as the disks between vertebrae or ligaments. It shows the spinal cord, nerve roots, and surrounding spaces, as well as enlargement, degeneration, or tumors.
The normal vertebral canal provides adequate room for the spinal cord and cauda equina. Narrowing of the canal, which occurs in spinal stenosis, may be inherited or acquired. Inherited conditions include a small spinal canal or curvature of the spine (scoliosis) that produces pressure on nerves and soft tissue and compresses or stretches ligaments.
Acquired conditions that can cause spinal stenosis are more common and include: are explained in more detail in the sections that follow.
Degenerative Conditions – Spinal stenosis most often results from a gradual, degenerative aging process. Either structural changes or inflammation can begin the process. As people age, the ligaments of the spine may thicken and calcify (harden from deposits of calcium salts). Bones and joints may also enlarge: when surfaces of the bone begin to project out from the body, these projections are called osteophytes (bone spurs). Other degenerative causes include disc herniation and spondylolisthesis, a condition in which one vertebra slips forward on another.
Osteoarthritis – The most common form of degenerative arthritis and is most likely to occur in middle-aged and older individuals. It is a chronic, degenerative process that may involve multiple joints of the body, including the spine. (see osteoarthritis link for more information) If osteoarthritis affects the facet joint(s) and the disk, the condition is sometimes referred to as spondylosis. This condition may be accompanied by disk degeneration, and an enlargement or overgrowth of bone that narrows the central and nerve root canals.
Other Acquired Conditions – tumors of the soft tissue, trauma, Paget’s disease of the bone, ossification of the posterior longitudinal ligament, and fluorosis
Nonsurgical treatment of spinal stenosis may be provided by internists or general practitioners. The disorder is also treated by specialists such as rheumatologists, who treat arthritis and related disorders; and neurologists, who treat nerve diseases. Orthopaedic surgeons and neurosurgeons also provide nonsurgical treatment and perform spinal surgery if it is required. Allied health professionals such as physical therapists may also help treat patients.
In the absence of severe or progressive nerve involvement, a doctor may prescribe one or more of the following conservative treatments:
- Nonsteroidal anti-inflammatory drugs, such as naproxen (Naprosyn)Â², ibuprofen (Motrin, Nuprin, Advil), or indomethacin (Indocin) reduces inflammation and relieve pain.
- Analgesics, such as acetaminophen (Tylenol), to relieve pain.
- Corticosteroid injections (or epidural injections) into the outermost of the membranes covering the spinal cord and nerve roots to reduce inflammation and treat acute pain that radiates to the hips or down a leg.
- Anesthetic injections, known as nerve blocks, near the affected nerve to temporarily relieve pain.
- Restricted activity (varies depending on extent of nerve involvement).
- Prescribed exercises and/or physical therapy to maintain motion of the spine, strengthen abdominal and back muscles, and build endurance, all of which help stabilize the spine.
- Lumbar brace or corset to provide some support and help the patient regain mobility.
Alternative (or complementary) therapies are diverse medical and health care systems, practices, and products that are not presently considered to be part of conventional medicine. Some examples of these therapies used to treat spinal stenosis include chiropractic treatment and acupuncture.
In many cases, the conditions causing spinal stenosis cannot be permanently altered by nonsurgical treatment, even though these measures may relieve pain for a period of time.
Surgery may be considered immediately if a patient has numbness or weakness that interferes with walking, impaired bowel or bladder function, or other neurological involvement. The effectiveness of nonsurgical treatments, the extent of the patient’s pain, and the patient’s preferences may all factor into whether or not to have surgery. The purpose of surgery is to relieve pressure on the spinal cord or nerves and restore and maintain alignment and strength of the spine.