Carpal tunnel syndrome comprises potentially disabling sensory and/or motor symptoms in the hand. Around 1 in 10 people develop carpal tunnel syndrome at some point, and it is particularly common in women (Hughes 2007), with one study in the UK indicating an incidence of 139.4 cases per 100,000 women per year and 67.2 cases per 100,000 men (Bland 2003). The condition carries considerable implications for employment and healthcare costs (Bland 2007).
The symptoms of carpal tunnel syndrome are caused by compression of the median nerve in the carpal tunnel at the wrist and include numbness, tingling, and burning sensations, and a dull ache in the hand and fingers (Hughes 2009). These symptoms are usually restricted to the thumb, index, middle and ring fingers, but may affect the little finger and/or the palm as well (Stevens 2005). They usually occur at night, often waking the patient from sleep, but can be relieved within a few minutes by shaking the hand (Stevens 2005). Pain sometimes radiates up the forearm as far as the elbow, and even as high as the shoulder or root of the neck (Stevens 2005). Other, less common, symptoms include weakness or clumsiness of the hand, and dry skin, swelling or colour changes in the hand (Bland 2007). Symptoms may recur during the day when the hands are used for carrying things, and for activities that involve holding them up, such as driving or using a keyboard (Stevens 2005).
Research has shown that acupuncture treatment may specifically help in the management of carpal tunnel syndrome by:
acting on areas of the brain known to reduce sensitivity to pain and stress, as well as promoting relaxation and deactivating the analytical brain, which is responsible for anxiety and worry (Hui 2010; Hui 2009);
increasing the release of adenosine, which has antinociceptive properties (Goldman 2010);
regulating the limbic network of the brain, including the hypothalamus and amygdala (Napadow 2007a);
inducing beneficial cortical plasticity (i.e. conditioning the brain to stop processing sensory nerve input from the affected fingers maladaptively, which leads to improved symptoms) (Napadow 2007b).