Arthritis Treatment: Lumbar Spinal Stenosis - An Increasingly Common Arthritis Problem

Lumbar spinal stenosis (LSS) is one of the most common maladies seen by rheumatologists. It is a condition that affects the low back. To understand what happens with this condition, it's important to briefly review the anatomy.

The lumbar spine consists of bones, called vertebrae, which are stacked one upon the other and separated by rubbery discs in the front and by joints (called "facet joints") in back. Down the center of this stack is a tunnel where the spinal cord is housed. The column of bones is supported inside and outside the tunnel by a series of ligaments.

LSS occurs when the spinal cord is compressed. There are three abnormalities that are responsible. First, the discs begin to bulge as a result of aging. They dry out and flatten. This leads to disc protrusion into the tunnel where the spinal cord passes. Second, the facet joints develop arthritis and the spurs from these facet joints protrude into the tunnel also. Finally, one of the ligaments that supports the spinal column inside the tunnel begins to hypertrophy and this also protrudes into the tunnel.

The end result is pressure on the spinal cord.

The history and physical examination are usually enough to suspect the diagnosis. Typically a patient older than 70 years will present with low back pain that is aggravated by walking or standing and relieved by sitting or by bending forward.

The pain radiates from the back into the buttocks and sometimes the thighs. Patients will walk with a wide-based gait- legs wider than usual because they feel unstable. This is because the normal signals that are sent from the brain to the feet are not being received so the patient's sense of where they are in space is abnormal.

Severe spinal stenosis is accompanied by bladder problems such as urinary frequency- going to the bathroom much more often than normal.

LSS is often confused for vascular claudication. This is a disorder where the blood flow to the legs is compromised because of narrowing of the arteries. The symptoms are similar. Also, narrowing of the spinal canal in the neck and hip disorders can also mimic lumbar spinal stenosis.

The diagnosis can be confirmed by either magnetic resonance imaging (MRI) or by CT scan of the low back.
The natural history of the disorder is one of progression. Conservative measures such as epidural steroid injections and physical therapy can be useful but most patients will require surgery which is often very effective.