By Brenda Goodman, MA
WebMD Health News
Reviewed by Brunilda Nazario, MD
April 13, 2016 -- Two new studies out Wednesday cast doubt on whether a common and costly operation used to relieve leg and back pain is always needed.
The studies found that the procedure, known as spinal fusion, wasn't any more effective at helping people walk or do daily tasks than a simpler surgery to relieve pressure on squeezed spinal nerves, a condition called spinal stenosis.
One study found fusion might improve a patient's quality of life, though -- a result researchers say is important and should help guide people in their treatment decisions.
But the spinal fusion procedure was also more intensive, resulting in more serious side effects and longer hospitals stays for patients. It's also much more expensive. A spinal fusion can cost over $88,000 before insurance, while the simpler surgery, called a laminectomy, is about one-quarter of that.
"I think it's important for patients to have a frank discussion with their surgeons," says Brook Martin, PhD, an assistant professor at the Dartmouth Institute for Health Policy and Clinical Practice.
"There's a lot that patients need to think about before they agree to a fusion," says Martin, who has tracked the rise in fusion procedures in the U.S., but was not involved in the research.
Stenosis, a narrowing of the spinal canal caused by arthritis in the joints between back bones, is a disease of aging. It causes searing or aching leg or back pain that gets worse with exercise, like walking. It may also cause numbness and weakness in a leg or foot. Some 100,000 Americans have surgery for spinal stenosis in their lower backs each year.
Over the last decade or so, there's been a dramatic shift in how these patients are treated.
In the early 2000s, studies show, most people with a diagnosis of stenosis in the lower back were treated with a procedure called a decompression, or a laminectomy, where surgeons carved away some of the bone in their vertebrae to give spinal nerves more room.
Doctors have feared that cutting away bone from the spine might weaken it. So in some cases, surgeons do a second procedure along with the decompression. The additional procedure, called a spinal fusion, inserts screws and rods into the bones above and beneath the area where the nerves had been painfully squeezed.
Fusions are especially popular for people who have a back bone, or vertebrae, that has slipped slightly out of alignment with the rest of the spine, a condition called spondylolisthesis. About 40% of people with stenosis also have spondylolisthesis.
Between 2002 and 2007, one study found that while the number of people getting simple decompressions for spinal stenosis dropped slightly, the number of patients who got fusion procedures increased 15-fold.
Spinal fusions are now the single most expensive surgery in the U.S., and are one of the most commonly performed surgical procedures, despite the fact that there's little good evidence to show they benefit people more than a decompression alone.
What the New Research Says
The two new studies in the New England Journal of Medicine aimed to test whether adding fusion to decompression really improved function and pain for back patients.
The first study, which was based in Sweden, included 247 patients between the ages of 50 and 80. Along with their stenosis, or a narrowing of the spinal canal, 135 people also had a back bone that was slightly out of alignment with the rest of the spine, or spondylosisthesis. The others only had stenosis.
About half of the group received only decompression surgery. The other half had decompression plus fusion. Before surgery, the groups reported about the same degree of pain and trouble walking and doing daily tasks.
Two years after their operations, all the patients in the study saw the same degree of improvement, no matter which procedure they had.
Patients who'd had fusion surgery could walk an average of 397 meters in 6 minutes, while those who'd only had the simpler procedure, decompression, were able to walk an average of 405 meters, a difference that could have been due purely to chance, so it wasn't significant. The results also didn't differ when the researchers considered only patients who'd had a spine bone out of alignment before the procedure.
People who had fusions spent about twice as long in the hospital, though, and had about twice the risk of infection -- 11 patients in the fusion group needed antibiotics to treat wound infections after their surgery, compared to five patients in the decompression group.
The researchers think their results are clear.
"In the vast majority of spinal stenosis patients, we think the treatment of choice should be decompression alone," says Peter Forsth, MD, an orthopedic surgeon at the Uppsala Clinical Research Center in Stockholm, Sweden.
Forsth says that during the period of his study, there was a shift in thinking in Sweden about how to treat people with stenosis. He said 4 or 5 years ago, about 40% to 50% of those patients would have gotten a fusion along with a decompression, but because of concerns over cost and side effects, the rate of fusions has dropped substantially. It's down to about 15% now, he says, and patients haven't suffered because of it.
The second study, done in the U.S., focused solely on people with stenosis who also had a bone out of alignment in their spines.
The U.S. researchers made the main focus of their study a scale that measured quality of life. Along with questions about their day-to-day pain, these patients were asked if they could lift and carry groceries, climb stairs, and about how far they could walk at a time. They were also asked about their overall energy and emotions.
The U.S. study included 66 men and women who were between 50 and 80. The researchers randomly assigned them to get either a simple decompression surgery or a decompression with a fusion.
After 2 years, the patients said they had the same amount of improvement in their ability to walk and do daily tasks, regardless of which procedure they'd had.
But patients who'd had the added fusion said they had a better quality of life.
Lead researcher Zoher Ghogawala, MD, a spine and brain surgeon at Lahey Hospital in Burlington, VT, says one way to think about the results is that no matter what procedure people had, after 2 years, they all improved and regained the ability to walk about the same distance and about the same speed. "But patients who had a fusion had less pain and enjoyed that walk more," he says.
He says rather than his study offering a "one-size-fits-all" answer about back surgery, he hopes patients and their doctors can use the research results to figure out what the right procedure might be.
He offers two examples to illustrate his point. The first, he says, might be a patient in their late 70s who can't walk and is in generally fragile health. Perhaps they recently recovered from a bout of pneumonia, and their children are concerned that a major operation like a spinal fusion might be too stressful.
In that case, his study shows "the simpler operation, the laminectomy, has a 70% chance of giving you a very good outcome," he says.
But for a different kind of patient, say someone who is in their early 60s and is used to being very active, "I think [this] study says have a fusion," he says.
Another thing for patients to consider, says Martin, is that decompression procedures have improved over the years. Doctors now remove less bone than they used to, which may lessen the need for a repeat surgery. Importantly, he says, the U.S. study didn't test these newer decompression methods.
Another Expert's Take
Frank Schwab, MD, chief of spine service at the Hospital for Special Surgery in New York City, says the studies are important and will help guide patients and doctors in their treatment decisions.
"I do think not everyone needs a fusion, I entirely agree with that," says Schwab, who was not involved in the research.
But he also says the question of which procedure might be best for someone can be nuanced, and he says the findings of these studies would be important for educating people about which treatment might work better for them.
"I would tell a patient in the U.S. that there are different studies out there," he says, "and different views on this same question."
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