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, such as osteoarthritis.
The symptoms of lumbar spinal stenosis generally develop slowly over time (most patients are over 50), and may come and go. Symptoms include: leg pain (sciatica) or leg pain with walking (claudication), as well as tingling, weakness or numbness that radiates from the lower back into the buttocks and legs. As symptoms worsen, they may become quite debilitating and it is estimated that 400,000 Americans suffer from leg pain and/or low back pain from spinal stenosis.
The cause of spinal stenosis is commonly associated with aging, although it 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 symptoms of pain, especially with activity.
Generally, patients with spinal 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 spinal stenosis rarely causes nerve damage and surgery is almost always elective.
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 diagnosis.
There are three major types of stenosis, and accurate identification is vital to effective treatment:
