THE QUESTION When the lower body pain of sciatica from a herniated disk persists, epidural steroid injections are a common treatment. Might oral steroids be a less invasive but viable option?

THIS STUDY involved 260 adults (average age, 46) who had pain radiating through their lower back and legs because of a herniated disk. They were randomly assigned to take the steroid prednisone or placebo pills for 15 days.

Prednisone dosage was tapered, from 60 milligrams a day to 40 mg and then 20 mg, with five days at each dosage. Standardized scales rating pain and mobility showed improvement for both groups. People who took prednisone reported, on average, a small gain in the ability to function, compared with those who took the placebo — a difference of about six points on a 100-point scale at three weeks into their treatment and seven points after a year.

Essentially no difference was found in their reporting of pain at any point during the study. About 49 percent of people who took prednisone (vs. 24 percent of the others) reported side effects early on, mainly insomnia, nervousness and increased appetite. Within the year, about 9 percent of both groups opted for back surgery.

WHO MAY BE AFFECTED? People with sciatica caused by a herniated, or ruptured, disk, a condition in which the jellylike substance that provides a cushion between the disks can leak out, irritating the sciatic nerve.

(Antonio Gravante/iStock)

That can lead to pain extending from the lower back and down the legs, as well as muscle weakness in the legs, all of which can limit mobility. Sometimes the condition goes away on its own; if not, treatment options include exercise, medication and surgery.

CAVEATS Data on pain and mobility came from the participant’s perceptions. No other dosage of prednisone was tested for comparison. The researchers wrote that “it may be argued that this dosage was insufficient.”

FIND THIS STUDY May 19 issue of JAMA, the Journal of the American Medical Association (www.jama.com).

LEARN MORE ABOUT sciatica at my.clevelandclinic.org/health. Learn about herniated disks at www.familydoctor.org.

The research described in Quick Study comes from credible, peer-reviewed journals. Nonetheless, conclusive evidence about a treatment's effectiveness is rarely found in a single study. Anyone considering changing or beginning treatment of any kind should consult with a physician.