How acupuncture stops pain is controversial. The prevailing model proposes that the insertion of needles elicits a biochemical cascade of neurotransmitters and hormones, some of which are inherently analgesic. Although the evidence confirms that this cascade does occur, the resulting analgesia is actually a side effect of the therapy, not its goal. In fact, acupuncture does not really treat pain at all. Rather, the goal of acupuncture is to identify and eliminate the structural abnormalities producing the pain in the first place.
The majority of pain is caused by the formation of palpable structures referred to in the Chinese as 啊是穴/Ashi Xue (pron. ah-shr shweh). These are discrete sites that mark a distinct thickening and/or contraction of the local muscle tissue and are analogous to the modern concept of the myofascial trigger point.
Histology of a myofascial trigger point: note the irregularity of the striations in the demarcated portion of the fiber compared to the uniformity of the striations in the healthy portion of the fiber.
Generally speaking, Ashi Xue cause pain in two ways: tensile asymmetry and impeded circulation. In the case of tensile asymmetry, thickening and contraction of the tissue produce asymmetrical tension upon the muscular attachment sites along the skeleton. This uneven distribution of force can irritate the muscle belly, its tendon, and can displace the joint. This asymmetry compromises the integrity of these structures thereby increasing their susceptibility to injury even resulting in degenerative diseases such as osteoarthritis.
Simultaneously, thickening and contraction of muscle tissue affect circulation by obstructing the local capillary beds that vascularize the muscle. This can lead to either deprivation of local blood supply resulting in further contraction of the affected fibers, or conversely it can lead to drainage problems resulting in swelling. In turn, this impeded circulation compounds tensile asymmetry and the problems therein, and ultimately prevents a natural recovery.
Diagram illustrating muscle-capillary anatomy: Capillaries enter muscle fibers for the purpose of facilitating oxygen/CO2 and nutrient/waste exchange. Because of their position within muscle bellies, capillaries are susceptible to alterations in the muscle's behavior.
Ashi Xue are identified through palpation. When squeezed or pressed, they are generally painful as the application of pressure increases the excess force they already produce. This tendency to hurt when pressed is what ultimately earned them the name, Ashi Xue, literally translating to "Ah! That's it!" point, reflecting the cries of the patient once a point is located.
Because Ashi Xue create pain by increasing tension, naturally the pain is eliminated by reducing that tension. Needles are utilized to puncture the affected muscle fibers preventing them from being able to pull. This significantly relaxes the muscle, alleviating the asymmetrical force applied to the skeleton, and disinhibiting circulation of the local capillary beds. As the punctured muscle fibers repair, the muscle's relaxed position and improved circulation allow for the punctured fibers to regrow in a lengthened position. This results in proper joint alignment, improved posture, and a substantial reduction in pain. In fact, it is not uncommon for a patient to experience 50-80% improvement after just one treatment.
The use of needles to puncture Ashi Xue means the historical emergence of acupuncture in Chinese antiquity is an example of proto-surgery. In which case, its effects must be understood as such. Acupuncture's success is thus contingent upon other factors beyond puncturing the appropriate locations. This is to say that circulatory problems, inflammatory conditions, and other internal medical disorders can complicate recovery. To optimize success, supplementary therapies such as cupping, guasha (scraping), moxibustion, herbal medicine, dietetics, and rehabilitative exercise are frequently employed. This means acupuncture on its own cannot be regarded as a panacea, but rather one tool in an array of tools that, when properly combined by a trained specialist, prove highly effective at eliminating the most common cause of pain.
- Loren Stiteler, LAc