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December 4 , 2006
Herniated disk, leg pain surgery study shows treatments work

by sarah goodwin

A groundbreaking study comparing surgery to nonsurgical treatment for people with herniated disks and related leg pain shows that both treatments help patients, but surgery may actually improve quality of life sooner, according to a study reported in November 22/29 issue of the Journal of the American Medical Association.

Participants with lumbar disk herniation who had surgery or non-operative treatments showed similar levels of improvement in the reduction of pain over a two-year period.

The study used a traditional statistical comparison known as intent-to-treat analysis. Trials that randomly assign patients to receive surgery or non-operative treatment are very difficult to perform, and many patients were in too much pain to stay in the non-operative group and had to switch over to surgery.

When looking at the as-treated analysis, which takes these cross-over patients into account, the surgical patients faired better in all parameters. In addition, some patients with severe pain who underwent surgery reported greater improvement earlier than those with non-surgical interventions.

Emory University Spine Center Director Scott Boden, working with co-researcher James Weinstein of Dartmouth Medical School and colleagues across the country, compared the outcomes of surgical and non-operative treatment for lumbar intervertebral disk herniation in the Spine Patient Outcomes Research Trial.

“This is truly a landmark study,” Boden said. “ Although some of the resulting headlines may suggest that there was no difference between surgery and non-operative treatments, the real answer lies in understanding the complete findings.

“We learned that patients make better choices when properly informed of their medical condition,” he said. “It was no surprise that patients switched out of their originally assigned treatment groups when their pain was too much to bear or because the pain improved on its own. How to properly account for these cross-over patients is a challenging task, but the data strongly favor the outcomes with surgery when patients were tabulated with the treatment they ultimately received.”

The JAMA report reflects findings from both a randomized study group, of which Boden is a study co-author, and an observational study group where participants designated their own treatment. The National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health funded the SPORT study in 1999 in hopes of measuring the efficacy and cost-effectiveness for these procedures. The disk herniation study results are the first to be published.

Some of the participating centers are members of the National Spine Network, a not-for-profit consortium of spine centers that collected the pilot data that ultimately led to SPORT, which received the largest award for a clinical trial in the history of NIAMS. Boden founded NSN in 1996 for the purpose of collecting outcomes data on treatments for spine disorders.

Experts say lumbar diskectomy — the surgical removal, in part or whole, of an intervertebral disk — is the most common surgical procedure performed in the United States for patients having back and leg pain. The vast majority of the procedures are elective.

However, lumbar disk herniation is often seen on imaging studies in the absence of symptoms as shown by Boden in a 1990 study. According to Boden, up to one third of normal volunteers may have evidence of disk herniation on their magnetic resonance imaging scans. With a high variation in regional diskectomy rates in the U.S. and lower rates internationally, questions can arise regarding the appropriateness and effectiveness of some of these surgeries, compared to non-operative care. Previously, evidence has been inconclusive on the optimal treatment.

The JAMA study enrolled patients between March 2000 and November 2004 from 13 multidisciplinary spine clinics in 11 U.S. states. The participants included 472 patients who were candidates for surgery, with imaging-confirmed lumbar intervertebral disk herniation and persistent signs and symptoms of radiculopathy for at least six weeks.

Patients were randomized to undergo diskectomy vs. non-operative treatment, which included physical therapy, education/counseling with home exercise instruction, and nonsteroidal anti-inflammatory drugs, if tolerated. There was follow-up at six weeks, thre months, six months, and one and two years.

The researchers found that adherence to assigned treatment was limited: 50 percent of patients assigned to surgery received surgery within three months of enrollment, while 30 percent of those assigned to non-operative treatment received surgery in the same period. This confirmed the expectation that some patients with severe pain were unable to continue with non-operative treatment and insisted on having surgery.

“Patients in both the surgery and non-operative treatment groups improved substantially over the first two years,” Boden said. “Between-group differences in improvements were consistently in favor of surgery for all outcomes and at all time periods but were small and not statistically significant where outcomes were assessed based on the therapy to which the patient was initially assigned.”

In addition, substantial improvements were demonstrated for all secondary outcomes, including sciatica severity, satisfaction with symptoms, self-reported improvement, and employment status, in both treatment groups, with the surgical group showing greater improvements.

“The intent-to-treat analysis likely underrepresents the true treatment effect due to the tendency for patients to switch treatment groups in a surgical trial for such a painful condition. Because of the high numbers of patients who crossed over in both directions, conclusions about the superiority or equivalence of the treatments are not warranted based on the intent-to-treat analysis alone,” he said. When tabulating patients with the treatments they ended up receiving, surgery clearly resulted in better outcomes.

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