In 1997, the National Institutes of Health Consensus Development Panel suggested that acupuncture may be effective or useful in treating 14 disorders, including headache. The history of the practice of acupuncture in the United States and the theoretical framework for acupuncture in Chinese medicine are reviewed. The basic scientific background and clinical application of acupuncture in headache management are discussed.
Historical note and terminology
Acupuncture is an important therapy in East Asian medicine, the traditional medicine of China, Japan, and Korea. With the growth of interest in alternative medicine, acupuncture has become more popular in the United States as a treatment option. Despite the fact that more scientific studies are needed to confirm the efficacy of acupuncture, the National Institutes of Health Consensus Development Panel issued a report in November 1997 stating that acupuncture may be effective in several conditions and situations (39). The National Institutes of Health Consensus Development Panel concluded that promising results have emerged, for example, showing efficacy of acupuncture in adult postoperative and chemotherapy nausea and vomiting and in postoperative dental pain. There are other situations such as addiction, stroke rehabilitation, headache, menstrual cramps, tennis elbow, fibromyalgia, myofascial pain, osteoarthritis, low back pain, carpal tunnel syndrome, and asthma, in which acupuncture may be useful as an adjunct treatment, an acceptable alternative, or be included in a comprehensive management program.
To western thinking, it is difficult to understand how acupuncture relieves headache by placing needles in the scalp, moreover, by treating points in the hands and feet. This essay briefly reviews the historical and theoretical framework for acupuncture, the scientific evidence for its efficacy in headache relief, and its safety profile.
Acupuncture is thought to have existed in China in one form or another since at least the Xia Dynasty (2000 to 1500 BC) (20). The earliest major source on acupuncture is found in the textbook Huang Di Nei Jing (Yellow Emperor’s Inner Classic) from the Han Dynasty (200 BC to 100 AD) (20). It was first brought to Europe in the 1700s and was introduced to the United States during the 19th to 20th centuries. Acupuncture treatment for lumbago was recommended in Sir William Osler’s The Principles and Practice of Medicine, from the first 1892 edition through the sixteenth and final edition in 1947 (20). In the 1950s China reported the use of electroacupuncture to obtain surgical analgesia (59). In 1996 the United States Food and Drug Administration changed the classification of acupuncture needles from Class III (experimental) medical devices to Class II (nonexperimental but regulated) medical devices (10). Being Class III hindered standard use of acupuncture, as it could only be performed in approved research settings (eg, hospital laboratories). By November 1997 the National Institutes of Health Consensus Development Panel had concluded that acupuncture was effective or useful in 14 disorders, including headache.
From the Chinese perspective, acupuncture is necessarily embedded in a complex theoretical framework that provides conceptual and therapeutic directions. The theories of yin and yang, 5 elements (the evolutionary phases of fire, earth, metal, wood, and water), Qi (vital energy), meridians, and collaterals provide the most important guidance for acupuncture treatment. These theoretical principles are briefly described below.
Yin and yang. The concept of yin and yang is the generalization of the 2 opposite aspects in related objects and phenomena in the natural world. The Chinese believe that all the objects in the universe include the 2 opposite aspects of Yang and Yin, for instance day and night, heat and cold, motion and tranquility, sympathetic and parasympathetic functions. Yin and Yang theory is among the most important principles underlying the practice of all Chinese medicine, including acupuncture. Disease and pain are the result of imbalance of the Yin and Yang, and acupuncture treatment aims to restore the balance.
Qi. The ancient Chinese believed that Qi is the basic substance composing the world, and all that matters in the universe appear by the movements and mutations of Qi. The vital energy or life force, Qi is fundamental to the description of nature in Chinese medicine. According to traditional Chinese tenets and beliefs, Qi circulates inside the meridians and supports every life process and every organic function. Chinese doctors think that pain is the result of stasis or blockade of the meridian Qi flow. An acupuncturist will apply needle stimulation aiming to reopen the related meridian by giving an external force to the energy and Qi. After the elimination of a severe blockage of Qi, pain will go away.
Jing-Luo. The Jing-Lou meridian network consists of major meridians (Jin channels) and minor meridians (Luo collaterals). Jing-Luo meridians are distributed throughout the body and inside the meridians Qi flows continuously. There are 14 major meridians including 12 “regular” and 2 “curious” meridians in the body (74; 19), which are commonly used in acupuncture practice and mentioned in the literature. They are named according to their distributed organs, including lung meridian, pericardium meridian, heart meridian, large intestine meridian, triple energizer meridian, small intestine meridian, stomach meridian, gallbladder meridian, bladder meridian, spleen meridian, liver meridian, and kidney meridian. The 2 major curious meridians are Ren MO (conception vessel) and Du MO (governor vessel).
Acupuncture points (acupoints), their anatomy and physiological characteristics. The anatomy of acupuncture points has been investigated (41). They are in the vicinity of the small or large peripheral nerves and their bifurcations, motor points of neuromuscular attachments, blood vessels, ligaments, and suture lines of the skull. Dung further found that all the acupuncture points in the face and forehead region are located along terminal or cutaneous branches of the trigeminal nerve and between muscular branches of the facial nerve (07). Acupoints were found to have lower electrical impedance compared to nonacupoints (45). Increased skin conductivity was also reported in the acupoints in rats and men, compared to the nonacupoints (23). It is still unclear what contributes to the difference of skin electrical properties. Based on the distinction of skin electrical impedance and conductivity, diagnostic and therapeutic probes have been developed. Such probes can help the acupuncturists or researchers to locate the acupoints by detecting the fall of cutaneous electrical resistance of the patients, and even be used for treatment of those points (56). A PET-CT study on 30 migraineurs was conducted to investigate the electroacupuncture-induced brain metabolism changes at specific acupoints and nonacupoints (70). Stimulation of the true acupoints increased the brain glucose metabolism in the middle frontal gyrus, postcentral gyrus, the precuneus, parahippocampus, cerebellum, and middle cingulated cortex, and it decreased in the left hemisphere of middle temporal cortex. In comparison, activation of the nonacupoints increased the metabolism in the posterior cingulated cortex, insula, inferior temporal gyrus, middle temporal cortex, superior temporal gyrus, postcentral gyrus, fusiform, inferior parietal lobe, superior parietal lobe, supramarginal gyrus, middle occipital lobe, angular, and precuneus, whereas it decreased in cerebellum and parahippocampus. In the aspect of Chinese medicine, acupuncture points are the sites through which the Qi of the organs is transported to the body surface by way of the above described meridians. The acupuncture points are divided into 3 categories: acupoints of 14 regular meridians (described above), extraordinary points, and Ashi points. (1) The acupoints of 14 regular meridians are the major components of the acupoint system. One example is Hegu, the fourth point at the large intestinal meridian. It is commonly used in the treatment of head or orofacial pain. (2) The extraordinary points are located beyond 14 regular meridians and play special roles in management. For instance, Taiyang locates at the temporal region and is the fifth extraordinary head and neck point. It plays an important role in migraine treatment. (3) Ashi points are also called tender points. They do not have specific names and defined locations. They are highly important in the diagnosis and treatment of headache and pain.