Acupuncture provided twice as many patients relief from lower back pain as did conventional drug and exercise therapy, which German researchers said on Monday might point to a "superplacebo" effect.
In a study of 1,162 adults with chronic lower back pain, 48 percent of those in a group who underwent between 10 and 15 treatments with traditional Chinese "verum" acupuncture reported at least one-third less pain and an improvement in functional ability, with lasting benefits.
That compared to 27 per cent of those reporting relief in the group undergoing drug and exercise therapy.
In verum acupuncture, 14 to 20 needles are inserted up to 1-1/2 inches deep at "medians" and other prescribed locations until the patient is said to experience a numbing sensation, called Qi.
A third group of patients underwent so-called sham acupuncture, where needles are inserted randomly and less deeply around the painful area while avoiding the medians. Of these, 44 percent reported relief from their back pain -- more patients than conventional therapy and only slightly fewer than traditional acupuncture.
"The superiority of both forms of acupuncture suggests a common underlying mechanism that may act on pain generation, transmission of pain signals or processing of pain signals by the central nervous system and that is stronger than the action mechanism of conventional (drug and exercise) therapy," study author Dr Michael Haake of the University of Regensburg, Bad Abbach, Germany, wrote in the Archives of Internal Medicine.
The researchers had hoped the two acupuncture techniques would identify whether the psychological, or placebo, affect was at work, in which patients' positive expectations persuade them the treatment helps. Patients in the study did not know the difference between the two techniques.
"The underlying mechanism may be a kind of superplacebo effect," Haake wrote.
By some unknown mechanism, acupuncture may relieve pain regardless of where the needles are placed, or the psychological and physical impacts combined to benefit more people in the verum acupuncture group, he wrote.
Between 70 per cent and 85 per cent of people complain of back pain at some point in their lives, according to the study.
"Acupuncture gives physicians a promising and effective treatment option for chronic low back pain, with few adverse effects or contraindications," Haake concluded.