April 11, 2001 -- "Oh! My aching back!"
It's one complaint that nearly all of humankind has in common. Many people just live with it, putting up with bouts of pain. But for a few select people, back problems are so severe they become chronic and debilitating, often requiring surgery.
Now a group of researchers has identified a genetic abnormality that dramatically increases the risk of one of the most common back disorders -- lumbar disk disease. They hope this genetic defect may eventually be a target for gene therapy.
"This is a breakthrough," study author Leena Ala-Kokko, MD, PhD, associate professor in the Center for Gene Therapy at Tulane University Health Sciences Center in New Orleans, tells WebMD. "It's quite possible that genetic defects may be the major cause of this disease." The research findings appear in the April 11 issue of TheJournal of the American Medical Association.
Lumbar disk disease affects about 5% of the population. It often causes a herniated disk to stick into the spine resulting in sciatica, a severe pain in the lower back radiating down the back of the thigh and knee to the foot. The disease also causes the disks to wear down, or degenerate.
Lumbar disk disease "can be a very nasty disease," Ala-Kokko tells WebMD. Patients "never really recover. [They] go on to have lots of operations, change occupation."
Certain genes regulate the formation of the disks -- the cushions between the bones in your spine -- and the cartilage that surrounds them. Defective genes can interfere with this process.
In analyzing the genes of 171 unrelated Finnish patients with sciatica, researchers found a genetic variation in 12% of patients with lumbar disk disease. Presence of the variation "increases risk of lumbar disk disease about threefold," says Ala-Kokko.
Though the genetic variation does not cause lumbar disk disease, people with this genetic change may be more susceptible to the degenerative forces that lead to the disease.
Although back pain is so common, "we haven't known what causes it," Ala-Kokko says. "This is a breakthrough in understanding the disease, which is very important in diagnosis and treatment. We know you should not operate on some patients because their condition will get worse, but we can't tell those apart from the others. Now we have a tool to start understanding this disease, so one day we can have a targeted treatment."
Her research group is already hard at work on a gene therapy for lumbar disk disease, which she says should be available in less than 10 years.
"We're excited about this discovery," says Robert S. Biscup, MS, DO, an orthopaedic surgeon and director of regional spine development at The Cleveland Clinic. "This research is trying to find the trigger mechanism by which the disk starts [to degenerate]. If we can find it and stop or reverse it, it may eliminate the need for these surgeries."
But if unrelenting back pain is already part of your life, what can you do right now?
Tremendous progress has been made in the last 15 years in understanding "how the spine works from a mechanical standpoint, how the muscles and joints work -- as well as understanding the mechanisms of pain, what seems to cause back pain," Biscup tells WebMD.
The spine is complicated because the muscles, bones, ligaments, spinal cord, and nerves all are a very intimate part of the anatomy in that area, explains Biscup.
"Degenerative spine disease is responsible mostly for back pain, and that in itself can be quite incapacitating. But when the nerves become involved, then patients experience severe leg pain, leg numbness, severe weakness ... and there can be combined problems, ... tremendous back pain because of spinal degeneration and nerve pain because of pinched nerves."
The two most commonly treated conditions that cause back pain are herniated disk and spinal stenosis, which occurs when the lower end of the spinal column becomes narrowed and compressed, squeezing the spinal cord or spinal nerves.
In the past, these conditions were treated with aggressive, major surgeries, requiring large incisions to expose the back side of the spine and remove a considerable amount of the spine's bony covering as well as muscle ligaments -- a procedure called a laminectomy.
Although laminectomy takes pressure off the nerves and relieves the severe leg pain and symptoms, says Biscup, "the spinal degeneration that caused the condition in the first place is still there and continues to progress to some degree. [Surgery] doesn't solve the problem, but treats fairly severe symptoms of the underlying spinal degeneration problem."
Microsurgery is the best treatment to date and has been available for 12 or 13 years, says Biscup. "But not all surgeons do microsurgeries," he says.
Microdiscectomy treats herniated disk and microdecompression is for spinal stenosis. Both of these minimally invasive procedures, which involve a 1-inch incision and use a laser and special scope, are done as outpatient surgery under a local anesthetic -- so patients go home the same day.
In microdiscectomy, the soft tissues causing pressure on nerves are gently removed using lasers, and 90% to 95% of the time patients have complete relief, Biscup tells WebMD. Microdecompression involves lasers to remove painful bone as well as the very thick ligament that is pinching the nerves; 90% of the time patients are relatively pain-free afterward.
"These procedures are very, very effective," says Biscup. People return to "normal lifestyles in a relatively quick period of time."