Definitive Guide to Lumbar Spinal Stenosis

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.

Spinal stenosis symptoms and causes

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.

Spinal stenosis diagnosis

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: lateral stenosis, which is the most common type; central stenosis; and foraminal stenosis.

Spinal stenosis treatment

Options for conservative (non-invasive) treatment for spinal stenosis include:

• Activity modification — Patients are usually more comfortable when flexed forward and, for example, can ease discomfort when walking by leaning on a cane, walker or shopping cart.

• Exercise — Though not a cure, a suitable exercise program in the hands of a good physical therapist may be helpful and can prevent further debilitation arising from inactivity. Stationary biking can be a good option because patients are sitting and positioned in a flexed-forward position while exercising.

• Non-steroidal anti-inflammatory drugs (NSAIDs) — As inflammation is a common component of spinal stenosis, anti-inflammatory drugs, such as ibuprofen or aspirin, may be helpful in treating spinal stenosis.

• Epidural injections — Injections are given on an out-patient basis and usually take 15 to 30 minutes. The physician guides a needle into the epidural space (located within the spinal canal between the vertebrae and the tough inner membrane called the dura mater or dura). Once the needle is in proper position, the epidural steroid solution is slowly injected. Epidural injections use steroids as an anti-inflammatory agent, and often include a fast-acting local anesthetic for temporary pain relief.

Spinal stenosis surgery

Spine surgery is the only way to change the anatomy of the spine and give the nerves more room. Choosing whether or not to have surgery depends on the degree of physical disability and pain the patient is experiencing. The two currently available surgical treatments are:

• Decompression surgery — (open laminectomy or microdiscectomy) decompresses the nerves by removing a portion of the enlarged facet joint, preventing the nerve from being pinched when the patient stands up. This surgery is effective in reducing pain and improving function in approximately 80% of cases. Over a 5-year period, the results tend to deteriorate, primarily due to the overall aging process and the progressive nature of osteoarthritis.

• Interspinous process device surgery — (e.g., the commercially available X-STOP and others in development, such as the Wallis® Posterior Dynamic Stabilization System). These devices are designed to open the space through which nerve endings pass, and limit backward extension of the spine, ideally relieving pressure on the nerves and alleviating pain. This surgical approach is relatively new, and the effectiveness of the procedure is still a matter of some debate.

Although laminectomy is the current gold standard for treatment of lumbar spinal stenosis and X-stop is now in use, new implantable devices are undergoing research and clinical testing:

• Facet joint replacement — where a reconstruction of the facet joint is implanted after decompression and removal of the degenerated facet (e.g., the Anatomic Facet Replacement System™ and Total Facet Arthroplasty System®).

• Total element replacement devices – where, after decompression, a device designed to preserve motion is implanted. For an in-depth discussion of new technologies and procedures in being investigated for spinal surgery, see Posterior motion preservation spine surgery: alternative to spinal fusion.

For an in-depth discussion of new technologies and procedures in being investigated for spinal surgery, see Posterior motion preservation spine surgery: alternative to spinal fusion.

By: Peter F. Ullrich, Jr., MD
October 29, 2007