MONDAY, Aug. 2 (HealthDay News) -- A new study suggests that injecting steroids straight into the spinal nerve might serve as an alternative to surgery for a kind of back pain known as sciatica when it's caused by herniated discs.

However, two experts said the findings don't tell the whole story.

According to the study authors, steroid injections can reduce the pain of sciatica. But research has suggested that, depending on where the injection is given, it doesn't work well compared to a placebo and a local anesthetic.

But one kind of steroid injection, known as transforaminal, sends the shots directly into the spinal nerve.

In the new study, researchers tried five injection strategies to treat sciatica on 150 patients.

More than half of patients treated with transforaminal injections reported pain relief. Only 7 percent of those treated with a local anesthetic did. The next most successful treatment was intramuscular steroid injections, which improved pain in 21 percent of patients who got it.

The study appeared in the current issue of Pain Medicine.

The transforaminal injections offer a modest immediate effect, but it's "substantial, and is not simply a placebo effect," study co-author Dr. Nikolai Bogduk, a researcher at the University of Newcastle in Australia, said in a news release from the journal's publisher.

The study suggests the injections can be an alternative to surgery, but it doesn't prove that, said Brook I. Martin, a researcher at Dartmouth-Hitchcock Medical Center in Lebanon, N.H. Other research, he said, has not shown that injections reduce the need for surgery or painkiller use.

Dr. Nick Shamie, an orthopedic surgeon at the University of California at Los Angeles School of Medicine, cautioned that sciatica patients should look upon injections skeptically. They can be helpful, he said, but "chances are you don't need it, and even if you get the procedure it will not have lasting benefits."

More information

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