What is lumbar spinal stenosis?

Spinal stenosis is narrowing of the spinal canal that occurs when excessive growth of bone and/or tissue reduces the size of the openings in the spinal bones. This narrowing can squeeze and irritate the nerve roots that branch out from the spinal cord, or it can squeeze and irritate the spinal cord itself. This may cause pain, numbness, or weakness, most often in the legs, feet, and buttocks.

Spinal stenosis occurs most often in the lower back (lumbar) area. When it occurs in the neck (cervical) area, the spinal cord may become squeezed, which if untreated can lead to nerve damage and paralysis. This topic is about lumbar spinal stenosis. If you need information on spinal stenosis of the neck, see the topic Cervical Spinal Stenosis.

What causes lumbar spinal stenosis?

Lumbar spinal stenosis is most commonly caused by age-related changes in the shape and size of the spinal canal. The aging process can cause thickening and hardening of connective tissues (ligaments). Joint disease (osteoarthritis) may destroy the tissue that protects and cushions joints (cartilage). These conditions contribute to deterioration of spinal discs, the development of bony growths (spurs), and damage to spinal joints, which in turn may narrow the space in the spinal canal (spinal stenosis).

What are the symptoms?

Many people older than age 50 have some narrowing of the spinal canal but do not experience symptoms. If your nerve roots or spinal cord becomes squeezed, symptoms may include:

• Numbness, weakness, cramping, or pain in the legs, feet, or buttocks. These symptoms get worse when you stretch or extend your back, such as when you walk, stand straight, or lean backwards. The pain gets better when you flex your spine forward, such as when you sit down or lean over a grocery cart.
• Stiffness in legs and thighs.
• Low back pain.
• In severe cases, loss of bladder and bowel control.

Symptoms may be severe at times and less severe at other times. Usually you will not be severely disabled.

How is lumbar spinal stenosis diagnosed?

A diagnosis of lumbar spinal stenosis usually is based on your history of symptoms, a physical examination, and imaging tests, such as magnetic resonance imaging (MRI), computed tomography (CT) scanning, and sometimes X-rays.

How is it treated?

In mild to moderate cases, symptoms can usually be controlled using medication to relieve pain, exercise to maintain strength and flexibility, physical therapy, or injections of medications (corticosteroids) that reduce inflammation.

Severe symptoms that are getting worse or restrict normal daily activities usually will not improve with nonsurgical therapy and may require surgery. In these cases, surgery to remove bone and tissue that are squeezing the spinal cord (decompressive laminectomy) can help relieve leg pain and allow you to resume normal daily activities.