Carpal tunnel syndrome (CTS) is a common condition that causes pain, numbness and a tingling sensation in the hand and fingers. This is caused by compression of median nerve that passes carpal tunnel and controls sensation and movement of the hand. If the nerve is entrapped in the tunnel, an unpleasant tingling, pain or numbness will occur in the distal distribution area which is in the hand and fingers. About 10% of people in the UK develop this condition. The symptoms include slowed median nerve conduction velocity, local pain and abnormal sensations such as tingling, burning, numbness etc. The symptoms develop gradually and are worse during the night. The affected fingers include thumb, index finger, middle finger and half of the ring finger. The risk of developing carpal tunnel syndrome include a family history of CTS, pregnancy, injuries to the wrist, other health conditions such as diabetes and rheumatoid arthritis and strenuous, repetitive work with the hand.
Acupuncture reduces pain dramatically. Acupuncture could reduce the pain completely or could reduce pain over 50% in some cases.
Research has shown that acupuncture could be an effective treatment for CTS and has greatly improved the symptoms in patients with CTS. Khosrawi S et al studied the acupuncture treatment for CTS using a randomised controlled trial. In this trial they recruited 64 patients who received 8 sessions of acupuncture treatment over 4 week period. They found that acupuncture improved the overall symptoms of CTS in these patients and nerve conduction velocity was improved as well. Another study by Kumnerddee W and Kaewtong A showed that 10 sessions of acupuncture over 5 weeks have better effect than that for night splinting in pain reduction. Yang CP observed the long term (1 year) effect of acupuncture on CTS. The patients with mild to moderate CTS received 8 sessions of acupuncture treatment over 4 week period. 1-year follow-up result showed that acupuncture treatment group had a significantly better improvement in overall symptoms, distal motor lantencies and distal sensory latencies compared to steroid group. These studies suggested that acupuncture has short term and long term effect in patients with CTS and acupuncture is a treatment option for patients with CTS.
Recently Maeda Y et al in Massachusetts General Hospital USA studied how brain contributes to the response to acupuncture in pain relief in patients with CTS. Brain response to electroacupuncture was assessed with functional MRI. The patients were allocated into three groups: local acupoints group, distal acupoint group and sham acupuncture group. In local acupoint group, two acupoints PC7 and TW5 on the affected wrist were used. In distal acupoint group, SP6 to LV4 acupoints were used. Sham acupoints were performed at nonacupoints locations on the affected wrist. They found that patients in the local and distal group reported reduced pain. Acupuncture group has greater reduction of abnormal sensation changes compared to sham group. Compared to sham group, local acupuncture produced greater activation in insula and S2 and greater deactivation in ipsilateral S1, while distal acupuncture produced greater activation in S2 and deactivation in posterior cingulated cortex. Brain activation in prefrontal cortex, SMA and S1 region was associated with analgesia.
Acupuncture is believed to stimulate the nervous system releasing neurochemical molecules to reduce pain. Acupuncture stimulates limb network in the brain and alter sensory process. Acupuncture reduces inflammation which may contribute to the mechanism.
Khosrawi S et al J Res Med Sci (2012) 17:1-7
Kumnerddee W and Kaewtong A J Med Assoc Thai (2010) 93:1463-9
Yang CP et al J Pain (2011) 12: 272-9
Maeda Y et al. Evid Based Complement Alternat Med (2013) Jun 17