WEDNESDAY, Feb. 20 (HealthDay News) -- The largest study of its kind concludes that surgery is better than nonsurgical treatments for spinal stenosis, a painful narrowing of the spine that stems from the normal deterioration that accompanies aging.

People who underwent an operation showed more improvement in pain, function, satisfaction and self-rated progress than those who received the typical, nonsurgical care.

But the procedure should not be overused, warned the authors of the study, which is published in the Feb. 21 issue of the New England Journal of Medicine.

"We don't want people to surmise that because this works, all spine surgery is good," said study author Dr. James Weinstein, chairman of the department of orthopedics at Dartmouth Medical School, in Lebanon, N.H. "These people all had very specific physical findings and diagnostic criteria. In these specific cases, this is a good operation. This is not a back pain operation."

Although surgery to correct the condition is common, particularly among those over the age of 65, Weinstein noted there was little objective evidence on the effectiveness of such a procedure.

"Studies have not been done in a way that might be generalizable or usable for the rest of country," Weinstein said.

The study involved two groups of patients: 289 who were randomized to receive surgery or usual nonsurgical care (physical therapy, education or counseling with home exercise instruction, and non-steroidal anti-inflammatory drugs if indicated), and 365 who did not want to be randomized and so were assigned to an "observational" group. In all, 13 clinics in 11 states were involved.

All participants had had at least 12 weeks of symptoms of spinal stenosis, without spondyloisthesis (when a vertebra in the lower part of the spine slips), as confirmed by imaging.

After two years, two-thirds of patients who had been randomly assigned to surgery had actually undergone surgery, while 43 percent of those in the nonsurgical group had also undergone surgery.

Surgery was twice as effective as nonsurgical treatment in addressing symptoms and improving actual function. Some improvements were seen as early as six weeks post-surgery, reaching their peak at six months and continuing for two years.

"I was hoping as a spine surgeon that it really worked, and we found that it did," Weinstein said. "It looks like from our results that surgery is better than non-surgery."

"People who received nonsurgical care did a little better, but not a lot. They pretty much stayed the same," Weinstein said. "Operative patients get a lot better, comparatively."

But there's an argument for both approaches. "One thing I learned is there's still a choice," Weinstein said. "Nobody got worse with or without surgery."

Another expert applauded the research.

"This study confirms what surgeons have felt all along," said Dr. Mark D. Rahm, assistant professor of surgery at Texas A&M Health Science Center College of Medicine. "It points out that people who are symptomatic enough to want to do surgery can feel good about the fact that it will likely improve their overall condition."

More information

The American Academy of Orthopaedic Surgeons has more on spinal stenosis.

SOURCES: James Weinstein, D.O., chairman, department of orthopedics, Dartmouth Medical School, and director, Dartmouth Institute of Health Policy and Clinical Practice, Lebanon, N.H.; Mark D. Rahm, M.D., assistant professor of surgery, Texas A&M Health Science Center College of Medicine, and director, Division of Spine Surgery, Scott & White, Temple, Texas; Feb. 21, 2008, New England Journal of Medicine