Crunch time for your back: spinal stenosis


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You're over the age of 50, and when you walk more than a short distance, you get pain or cramping in your legs and lower back. The pain subsides when you sit down. But, you notice the distance you can walk before the pain recurs is getting shorter and shorter, and when the pain recurs, it is more severe.

You may have spinal stenosis, a narrowing of the spinal column that puts pressure on the spinal cord (central canal stenosis), or a narrowing of the openings where spinal nerves leave the spinal column (lateral foraminal stenosis).

"Stenosis" is derived from the Greek word for choking. If the pressure is on the lower part of the spine, the result is pain or numbness in the legs. If the pressure is on the upper part of the spine, the pain and numbness most likely will be in the neck and shoulders. People with more severe cases may have trouble with their balance and may have difficulty controlling their bladder and bowels.

Seniors who have the most common form of stenosis often walk hunched over because that reduces pressure on the spine, said Joseph Maroon, vice chairman of the department of neurological surgery at UPMC. When the spine is flexed forward, more space is available for the spinal cord, causing a reduction in symptoms.

PG graphic: Spinal stenosis
(Click image for larger version)

Spinal stenosis is chiefly a degenerative disease that occurs with age. As we get older, the ligaments of the spine may thicken and calcify, and our bones and joints may enlarge. Stenosis can also be caused by a bulge (herniation) of the intervertebral discs. There's not much you can do to keep from getting it.

The odds are you won't. Estimates of the number of seniors who suffer from spinal stenosis vary widely, because symptoms occur gradually, and many who have the disease in its early stages are not aware of it.

Spine surgeon Nicholas Shamie, a spokesman for the American Academy of Orthopaedic Surgeons, estimates that 1.2 million Americans have lumbar (lower back) stenosis, the most common form. But there are 76 million Americans over the age of 50, so if Dr. Shamie's figure is correct, only about 1.6 percent of seniors have this disease. Risk increases with age and is somewhat greater for women. Genetics plays a role. Some people are born with a more narrow spinal canal.

Risk is also greater for athletes such as gymnasts, construction workers and others whose jobs or activities put stress on their spines.

"Somebody who runs a jackhammer all their life -- basically abuses their spine -- can be predisposed," said Brian Hagen, a sports medicine physical therapist at UPMC's Center for Sports Medicine, whose specialty is rehabilitation involving the spine.

"The more wear and tear, the more stenosis you get," said Donald Whiting, vice chair of the department of neurosurgery at Allegheny General Hospital.

Although there isn't much you can do to keep from getting spinal stenosis, there's a lot you can do to ameliorate its effects.

Perhaps the most important is to lose those extra pounds.

"Being overweight doesn't help," said Jack Wilberger, chairman of neurosurgery at AGH. "It certainly puts more strain on the spine and on the back. We are not currently aware of any other thing that would increase the risk of spinal stenosis."

Exercise can help keep the weight off and is a boon in itself. Exercise that strengthens supporting muscles, including those in the abdomen, can take some pressure off the spine. Tight muscles pull and torque the spine, which can make symptoms of spinal stenosis worse. By helping to maintain flexibility, exercise can loosen those muscles up.

"My advice to folks is to stay as active as they can," Dr. Wilberger said. "If you don't use those joints, the more difficult it becomes to use them."

People should maintain good muscle strength, Mr. Hagen said. "Maintaining good posture and core strength definitely reduces the forces in the spine which lead to premature degenerative changes."

Most beneficial are flexion exercises such as situps, which bend the spine, Mr. Hagen said. "These are helpful because they open the space in the spinal canal and the lateral foramin."

Swimming and water exercises are very good, too, Dr. Wilberger said. He recommended the Silver Sneakers program sponsored by Highmark and other health insurers as "a low-impact activity that folks in this age bracket can easily do." Others recommend bicycling and Tai Chi.

Spinal stenosis can be difficult to diagnose because its symptoms resemble those of other degenerative diseases. If a physical exam is insufficient, an MRI -- the imaging test of choice, according to the Mayo Clinic -- can show pressure on the spinal cord or spinal nerves. A CAT scan can reveal herniated disks and bone spurs. A spinal X-ray can't confirm stenosis, but it can rule out other problems that have similar symptoms.

Once stenosis has been diagnosed, "We treat conservatively with anti-inflammatory drugs and some physical therapy," Dr. Wilberger said. "That works for about 70 percent. When things get so bad people can't function in a reasonable manner, then surgery is an option."

A candidate for surgery, Dr. Maroon said, is a patient who tells him: "I used to walk a mile, than a half a mile, now I need a cart to get around Giant Eagle because of the pain in my legs."

"People who have acute onset of symptoms typically do very well with conservative treatment," Mr. Hagen said. "There was some sort of event that caused this problem. Those who have symptoms occur gradually over a period of time are more likely to require surgery."

"Surgery has a long track record," Dr. Wilberger said. "In general, 70-80 percent get very good relief, 10 percent get some relief."

The traditional surgical treatment is to remove the bone, bone spurs or ligaments that are pushing on the nerves. This treatment is called "decompression."

New, less-invasive procedures make it possible to operate on patients for whom in years past surgery was considered too risky, Dr. Maroon said.

It's not unusual for his patients to come to him in a wheelchair, Dr. Maroon said.

Surgery "gives them their life back," he said. "They're up immediately. Approximately 90 percent of my patients are back home within 24 hours. It's very dramatic."

But patients whose stenosis is more extensive, or who have other conditions, too, may require more complex surgery.

The number of complex spinal surgeries -- which combine decompression with other procedures -- went up by 15 times between 2002 and 2007, according to a study published in the Journal of the American Medical Association in 2010. The complication rate arising from these surgeries was more than twice as high as for decompression surgery alone, and the cost of a patient's hospital stay was more than three times as high. Some physicians -- including the lead author of the JAMA study -- think the risks of these surgeries outweigh the benefits.

Neurosurgeons at Allegheny General Hospital are evaluating a device that could reduce those risks. Facet joints are small stabilizing joints located between and behind adjacent vertebrae in the spine. They provide about 20 percent of the twisting ability in the neck and the lower back. If they become inflamed, they can cause spinal stenosis.

Currently, if the facet joints are removed to relieve pressure on the spinal cord, vertebrae must be fused together to provide the stability the facet joints once provided. But spinal fusion permanently limits range of motion.

The ACADIA Facet Replacement System AGH neurosurgeons are evaluating replaces degenerated facet joints with artificial ones, so spinal fusion isn't required for stability.

With this device, surgeons may be able to eliminate their patients' pain "while preserving their ability to bend and stretch," Dr. Whiting said.

"As long as the disc in front is functional, you can retain your motion," he said. "This is very promising. I think it's pretty cool."

AGH is one of 30 hospitals nationwide taking part in the clinical trial, which will be conducted over the next seven to 10 years.

health

Jack Kelly: jkelly@post-gazette.com or 412-263-1476.


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