Spinal stenosis

Pressure on nerves in the lower spine is a common cause of lower back pain in older women

PEOPLE WHO HAVE pain in their lower back shouldn't just assume it's the result of back strain. It could be lumbar spinal stenosis (LSS). While 65% of people have low back pain at some time, in over half of them, lumbar spinal stenosis is the predominant cause of their pain.

LSS occurs when there's a narrowing of the spinal canal or the space between the vertebrae where nerves pass through to the leg and lower back muscles. The compression of the nerves causes pain in the legs and the back while walking. "It's not the low back pain that prompts people to seek help, but the leg pain, often in both legs, which can be quite severe and interfere with functioning," says Elisabeth Lachmann, MD, a clinical associate professor of rehabilitation medicine at the Weill Medical College of Cornell University.

Many causes of pain

LSS can have many causes, including osteoarthritis (the wearing away of cartilage that cushions bone), bone spurs, joint overgrowth due to other forms of arthritis, or flattening of the disks between the spinal vertebrae, all of which press on and narrow the spinal canal and places where nerves exit the lower spine (lumbar region). The resulting pressure on the nerves triggers pain, but it can also produce numbness, tingling, and heaviness or weakness in one or both legs when you walk, explains Dr. Lachmanii. It's most common in women over age 50.

"You don't get this pain while you are sitting down. In fact, women with lumbar spinal stenosis ieel better when they sit because it relieves pressure on the spine and the nerves. Women also tend to lean forward as they walk because that makes their pain better. It's called the 'shopping cart sign,' as if they are walking along pushing a cart. It's a classic sign of lumbar stenosis," says Dr. Lachmann. In severe cases, women may be able to stand or walk ior only a few minutes due to the pain.

The diagnosis is confirmed by magnetic resonance imaging (MRI), which can rule out other causes of pain such as spinal tumors.

Steps to ease pain

Symptoms can often be relieved with conservative treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) to relieve pain, and a program of exercise and physical therapy to stretch and strengthen the muscles in the lower back and legs can often improve symptoms. Applying moist heat can increase blood flow, relax tight muscles, and relieve local pain.

"Weight loss also helps. Less weight around the abdomen puts less pressure on the lower back. Once you lose the weight, you can start working on some exercises to strengthen and stretch muscles to decrease muscle spasms," remarks Dr. Lachmann.

"We prescribe exercises to minimixe curvature of the lower spine, specifically to strengthen the abdominal muscles, loosen up the flexor and the abductor muscles of the hip and stretch them out. Then we try to stretch out the back extensor muscles. I also encourage patients to become involved in some type of aerobic activity," she explains.

Beneficial aerobic activities include walking on a treadmill using ami swings to loosen spinal muscles (a $ to 7-degree incline may he more comfortable than a level surface); walking in the shallow end of a swimming pool against the resistance of the water, or doing the side stroke. Bicycling or using a cross-country ski machine can also provide strengthening for the back and hips, says Dr. Lachmann.

Corticosteroid injections into the epidural space around the spinal canal may provide short-term pain relief, says Dr. Lachmann. "Epidural steroids, while very helpful, do not change the underlying problem which is producing the symptoms."

When surgery is needed

Surgery to relieve pressure on the nerves is done when conservative treatment approaches fail to relieve pain, or when pain is chronic and severe.

The surgery removes bone and other tissues from the vertebrae to relieve pressure on nerves. More than one vertebra may be treated. The most common procedure, called a decompressing laminectomy, removes part of the vertebra, relieving pressure and creating more space for the nerves. If the vertebrae have been damaged, spinal fusion to stabilize them may be needed. It can take 6 weeks to fully recover from the procedure, and physical therapy is also needed.

"Whether one has pain from mild spinal stenosis or severe spinal stenosis, no one can predict how a patient will do with decompressing laminectomy. Even in the hands of the best surgeons, we are always uncertain of functional outcome following the surgery," remarks Dr. Lachmann. However, less than 10% of people with LSS will need surgery.

Copyright 2003 Women's Health Advisor. Reprinted with permission, Englonder Communicotions. For subscription ond other infbrmotion, coll (800) 424-7887.

Copyright American Association of Medical Assistants Sep/Oct 2003
Provided by ProQuest Information and Learning Company. All rights Reserved