Patients treated with 10 sessions of acupuncture over three months reported less pain at a 24-month follow-up than patients who did not get the therapy.

The difference between the two groups was small, however, with researchers concluding there was a "small benefit" at two years.

Study co-author Hugh MacPherson, PhD, characterized acupuncture's impact on the patients' pain as modest, but he tells WebMD that the ancient Chinese medical treatment has proven its worth as an adjunct to traditional therapies for nonspecific back pain.

"Acupuncture definitely has a role in the treatment of low back pain," he says. "And it seems to be associated with longer-term effects than anyone has realized."