Effects of TENS applied to acupuncture points distal to a pain site

Abstract

The observation that patients with head and neck cancers undergoing radiotherapy continued to experience pain despite moderate analgesics prompted the first author to investigate whether transcutaneous electrical nerve stimulation (TENS), applied to acupuncture points away from the pain site, would increase the pain relief effect (Table 1). The pilot study involved four patients with head and neck cancers undergoing radiotherapy. The subsequent randomized trial involved 14 patients undergoing inguinal herniorrhaphy. Pain relief in the group receiving TENS on true acupuncture points was compared with that in patients receiving TENS on non-true points. Pain relief was evaluated by pain score and morphine use in the 24 hours following operation. Results of the pilot study suggested that TENS applied to acupuncture points enhanced pain relief. Patients in the follow-up trial had similar pain scores. Those given TENS to non-true acupuncture points required more morphine than those given TENS to true points, suggesting that endogenous opioids released from acupuncture points were boosting pain relief.