Definitive Guide to Lumbar Spinal Stenosis

Fig. 1: Stenosis
(larger view)

As we age, the spine changes, often leading to a degeneration of the vertebrae (bones), discs, muscles, and ligaments (connective tissues). These changes may lead to spinal stenosis.

The term “stenosis” comes from the Greek word meaning “choking” and is often the result of degenerative conditions like osteoarthritis (see Figure 1). When the spinal nerves in the lower back are choked, lumbar spinal stenosis occurs and most often leads to different types of leg pain, as described in more detail below.

Lumbar Spinal Stenosis Symptoms

The symptoms of lumbar stenosis generally develop slowly over time (most patients are over 50), and may come and go. Lumbar stenosis symptoms may include:

• Leg pain (sciatica)
• Leg pain with walking (claudication)
• Tingling, weakness or numbness that radiates from the lower back into the buttocks and legs.

As lumbar spinal stenosis symptoms worsen, they may become quite debilitating. It is estimated that 400,000 Americans suffer from leg pain and/or low back pain from lumbar spinal stenosis.

Lumbar Stenosis Causes

The cause of spinal stenosis in the lumbar spine is commonly associated with aging. With that said, degenerative lumbar stenosis may occur in younger people who develop a curvature of the spinal canal or suffer a spinal injury. The facet joints (small stabilizing joints located between and behind vertebrae) tend to get larger as they degenerate, and can compress the spinal nerve roots in the lower back, often producing lumbar stenosis symptoms of pain, especially with activity.

Generally, patients with lumbar spine stenosis are comfortable sitting, but standing upright further decreases the space available for the nerve roots and can block the outflow of blood from around the nerve. Congested blood then irritates the nerve, causing pain. It is important to note that lumbar stenosis which causes severe nerve damage is rare, and that surgery is almost always elective.

Lumbar Stenosis Diagnosis

See the Spinal Stenosis
Interactive Video

When a patient presents with the typical symptoms of lumbar spinal stenosis (leg pain, with or without back pain, which is aggravated by walking), a conclusive diagnosis is made using imaging studies from an MRI scan or a CT scan with myelogram (using an x-ray dye in the spinal sack fluid). Physical examination alone does not yield a conclusive lumbar stenosis diagnosis.

There are three major types of stenosis, and accurate identification is vital to stenosis treatment:

• Lateral stenosis. The most common type of spinal stenosis, lateral stenosis occurs when a nerve root that has left the spinal canal is compressed by either a bulging disc, herniated disc or bone protrusion beyond the foramen (a bony, hollow archway through which all spinal nerve roots run).
• Central stenosis. Occurring when the central canal in the lower back is choked, central stenosis may lead to compression of the cauda equina nerve roots (the bundle of roots that branch off at the bottom of the spinal cord like a horse's tail).
• Foraminal stenosis. When a nerve root in the lower back is pressed on and trapped by a bone spur just prior to leaving the spinal canal from the lateral foramen, lumbar foraminal stenosis occurs.

• Article written By:
• Peter F. Ullrich, Jr., MD

August 10, 2009

Print