A narrowing of the open spaces within the spine is called spinal stenosis. It can put pressure on the spinal cord and the nerves that travel through the spine. Spinal stenosis occurs most often in the neck and lower back. The narrowing may involve a small or large area of the spine.
Spinal stenosis is most commonly caused by wear-and-tear changes in the spine related to aging. As people age, the ligaments of the spine may thicken and calcify (i.e. 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). Two forms of arthritis that may affect the spine and cause spinal stenosis are osteoarthritis and rheumatoid arthritis. It may also be caused by tumors, trauma, Paget’s disease (an uncommon bone condition that results in deformity), and ossification (i.e. calcium deposits) of a ligament located inside the spinal canal. Some people inherit a small spinal canal or have a curvature of the spine (scoliosis) that produces pressure on nerves and soft tissue and compresses or stretches ligaments. While spinal stenosis may occur in younger people who are born with a narrowing of the spinal canal, or who incur an injury to the spine, spinal stenosis is most common in men and women over 50 years of age.
In rare cases, severe back pain can be a sign of cauda equina syndrome (CES), a condition that among other factors, can be caused by spinal stenosis. It is serious and usually requires urgent surgical treatment. CES affects a bundle of nerve roots called cauda equina (Latin for horse’s tail). These nerves are located at the lower end of the spinal cord in the lumbar spine.
While some people have no signs or symptoms, when symptoms occur they depend on the location of the stenosis.
- Pain, numbness, muscle weakness, and problems with bladder or bowel function
- Stenosis in the neck may cause numbness, weakness, tingling in one or both legs, foot, arm or hand
- Stenosis in the lower back: pain, cramping in legs while standing long periods of time or when walking
- Severe cases: affected nerves in bladder or bowel, leading to incontinence
Patients who experience severe leg pain when walking (also called lumbar stenosis and neurogenic claudication) are often candidates for surgery. The goal of surgery is to alleviate pain and allow a return to function in everyday activities.