Review: acupuncture analgesia in clinical trials.

Acupuncture treatment has been accepted worldwide. Many clinical trials have been conducted especially in analgesia. The present review includes almost all the important trials since 1970. Among all the pain conditions, postoperative pain, lower back pain, osteoarthritis of the knee and chronic headache are the most popular topics. We found that there are diverse conclusions in each condition; however, most trials agree that acupuncture is an effective therapeutic strategy for analgesia. As with regard to the placebo effect, there is no consensus. In chronic headache treatment, the placebo effect of acupuncture seems to be large. However, in osteoarthritis, the placebo effect is minimal. Another issue is the non-specific physiologic response to piercing the skin. We believe that this effect produces analgesia in some heterogeneous syndrome such as lower back pain. However, this effect is not superior to the specific therapeutic effect of acupuncture based on TCM theory in all the pain conditions reviewed here. We also notice that the design of the sham acupuncture or the placebo has great impact on the result. Rigorous design can minimize the non-specific and placebo effects of acupuncture. Therefore, the real effect of acupuncture can be investigated well. We conclude that acupuncture is a proven treatment for relieving pain. This conclusion is based on specific effects of acupuncture rather than placebo.