MONDAY, April 16 (HealthDay News) -- New research suggests that epidural steroids provided better relief for some patients with sciatica, a searing pain that shoots from the lower back straight down the leg, than Enbrel, a newer type of anti-inflammatory drug.

Yet the differences were "modest" and did not reach statistical significance. And while more patients reported pain relief one month after receiving epidural steroids, the relief didn't necessarily last. At six months, steroids weren't any better than Enbrel (etanercept) or a third treatment tested, injections containing saline and a local anesthetic.

"We found a pretty strong suggestion that steroids were better than both of the other treatments, and the etanercept wasn't better than saline, in the short-term," said study author Dr. Steven Cohen, a professor of anesthesia at Uniformed Services University of the Health Sciences and director of pain research at Walter Reed Army Medical Center, in Bethesda, Md.

The study is published in the April 17 issue of the Annals of Internal Medicine.

Back pain is the leading cause of disability in people under age 45 globally, according to background information in the article. While it was previously believed that "mechanical" problems such as degenerative disks or arthritis caused the vast majority of back pain, "there's a growing realization that nerve-related pain accounts for a greater proportion of people with back pain than was previously appreciated," said Cohen, who is also affiliated with Johns Hopkins University School of Medicine.

Like many other forms of pain involving the spine, sciatica is notoriously difficult to treat, Cohen added.

Epidural steroids have been used to treat back pain for more than 50 years. There have been nearly 40 randomized, placebo-controlled trials -- the gold standard of research -- trying to determine if steroids are effective, Cohen said.

Even after decades of studies, there is still controversy over how effective steroids really are and how long the relief lasts.

"Most people agree that epidural steroids are beneficial in people with nerve-related back pain. Some people say it's effective in the short term but not long-term, or that it helps pain but doesn't help function, or that it helps pain but doesn't decrease need for surgery," Cohen said.

More recently, researchers have tried treating back pain with a newer type of anti-inflammatory pain medication, etanercept, which is used to treat rheumatoid arthritis and other autoimmune disorders.

In sciatica, it was previously believed that the pain emanated from a degenerating disc that pressed on a nerve, but experts now believe that the degenerating disc releases inflammatory molecules known as cytokines, leading to inflammation and pain. Etanercept, a tumor necrosis factor (TNF) inhibitor, blocks those cytokines.

Yet "the evidence doesn't support use of epidural etanercept for sciatica at this time," said Dr. Roger Chou, who chaired the committee that wrote the American Pain Society's guidelines on treating lower back pain.

In the study, 84 adults suffering with sciatica for less than six months received two epidural injections, each two weeks apart, containing either local anesthesia and saline, local anesthesia and steroids, or etanercept. Patients who received epidural steroids received transforaminal injections, a newer technique that studies suggest is more effective but also carries a higher risk of complications, Cohen said.

At one month, about 75 percent of patients reported at least a 50 percent drop in leg pain after the steroid epidural. About 42 percent in the etanercept group and 50 percent in the saline group reported similar pain reductions.

At six months, slightly more of the saline group (40 percent) and etanercept (38 percent) continued to have some pain relief, compared with 29 percent in the steroid group.

The study shows that "transforaminal epidural steroids might be slightly better than epidural saline at short-term follow-up, but any benefits are gone with longer-term follow-up," said Chou, an associate professor of general internal medicine at Oregon Health and Science University, in Portland.

"The differences aren't huge, averaging about one point on a 10-point pain scale," he said. "There weren't any clear benefits from epidural etanercept."

Importantly, people got better no matter which intervention they received, Chou added.

"I think it underscores our previous (APS) recommendation to consider epidural steroids as a potential option for patients who are looking for short-term pain relief, but to be very clear to patients that these benefits do not appear to last and they have a good chance of improving without the injection," Chou said. "I think a lot of doctors (and patients) think that epidural steroid injections are much more effective (and longer lasting) than the evidence shows that they really are."

Even though etanercept didn't work great in this study, researchers say it should continue to be studied for use with sciatica. People in the study got a low dose of the drug, 4 milligrams (mgs), whereas people who receive it for rheumatoid arthritis receive 25 mgs or 50 mgs. It's possible a higher dose would work better, Cohen said.

The bottom line is that better treatments for sciatica are sorely needed, Cohen said.

Epidural injections of steroids can cause complications, including paralysis and death.

Recommendations limit the number of injections people can get in a year to decrease other side effects, including ulcers, immune-system suppression, wound-healing interference and raising blood sugar levels in diabetics, Cohen said.

More information

The U.S. National Library of Medicine has more on sciatica.