Dry needling is an invasive therapeutic procedure that involves the insertion of solid filament needles for the purpose of relieving muscle pain. Although it is similar to Chinese acupunture techniques, dry needling is based on Western neurophysiological and anatomical principles. The treatment is used specifically for pain control in the musculoskeletal system and primarily for people who suffer from myofascial pain syndrome.
Myofascial pain syndrome, which is characterized by pain in the muscles and associated connective tissue, can be acute or chronic. It is caused by overloading of the muscles by factors such as trauma, disease, infection, homeostatic imbalance and psychological stress. This loading on the muscles subsequently causes trigger points (TrPs) to form. Trigger points were first identified by doctor Janet Travell as hyperirritable points in the skeletal muscles because of the localized contraction of small numbers of muscle fibers within the larger muscle, forming a knot that produces and maintains the pain associated with myofascial pain syndrome. These knots, which are the main diagnostic indication of the condition, are identified by palpation and the associated symptoms of tenderness and pain.
Initial treatment of these trigger points involved inserting a needle through the skin and into the muscle at the TrP, then injecting an analgesic. In the late 1970s, it was found that pain relief in patients who had myofascial complaints seemed to be more correlated with the actual pressure of the needle at the TrP than any pain-relieving medication used. For dry needling to properly alleviate pain, however, the needle must make accurate contact with the TrP.
If the TrP is properly stimulated, a local twitch response will be produced. This local twitch response is an involuntary reflex of the spinal cord, which produces a contraction in the tightened muscles. The analgesic effect of dry needling is thought to be caused by the subsequent stimulation of the production of opioids that are already produced naturally by the body, including endorphins, endomorphins, dymorphins and enkephalins.
The actual efficacy of dry needling was not well known as of 2011, because studies that examined the technique and its effects had small samples sizes and poor quality data. This treatment method is practiced by chiropractors and physical therapists in countries such as Canada, Great Britain, South Africa, Switzerland and the Netherlands. Dry needling also is performed in Chile, New Zealand and Spain. In the United States, dry needling is used as a therapeutic technique but is legal only in certain states.