Acupuncture is one component of traditional Chinese medicine. As such, it has its theoretical roots in Taoist ideas about the universe, living systems, health, and disease. Modern scientific scrutiny has already yielded more information about acupuncture mechanisms than for any other alternative therapy. The discovery of opioid receptors and endorphins has led to a large number of investigations into the role these receptors and ligands play in producing acupuncture analgesia. Nearly all such studies support the conclusion that acupuncture analgesia is mediated in part by the opioid system. Acupuncture analgesia can be reversed with administration of naloxone [7–9]. Increased levels of endogenous opioid following acupuncture have been directly measured in humans [10, 11]. Antiserum to opioid receptors applied to the periaqueductal gray matter has been shown to block experimental acupuncture analgesia in primates.

Han and Terenius reviewed a number of studies that demonstrate the importance of biogenic amines in acupuncture analgesia [12]. Ablating the descending inhibitory pathway for pain at the dorsal and medial raphe nuclei blunted acupuncture analgesia. Blocking serotonin receptors in rabbits and rats also diminished acupuncture analgesia. Administering a serotonin precursor potentiates acupuncture analgesia. Serotonin and its by-products are increased in the lower brainstem during acupuncture analgesia. Other neurochemical mediators of experimental acupuncture analgesia have been implicated in preliminary investigations including substance P, CGRP, CCK, and C-fos [13].

That stimulation of tissue, including neural tissue, produces analgesia has only recently gained acceptance in conventional medicine. Neurosurgeon Norman Shealy pioneered the use of transcutaneous electrical nerve stimulation (TENS) in the 1970s—less than a decade after Melzack and Wall published their gate theory of pain modulation that postulated a competitive inhibition of pain by non-noxious stimuli. Wallin and colleagues showed that spinal cord stimulation inhibits long-term potentiation of spinal wide dynamic range neurons. Hanai demonstrated a similar response to peripheral nerve stimulation [14].

History of Acupuncture. When New York Times reporter James Reston wrote about his experience with acupuncture while covering the US–China Ping-Pong games which opened China to the West in 1971, the reaction in the United States was one of intrigue and skepticism. How could pain be alleviated by inserting, of all things, needles into the body? It was unfathomable to the western mind that needles would produce an effect without injecting something through them or taking something out. Words like voodoo, magic, trickery, and scam were found in every media report and conversation. Teams of American scientists were sent over to verify and scrutinize this mystical procedure. The Chinese must have been surprised and puzzled by the flurry of interest. After all, acupuncture along with herbal therapies was just part of their everyday system of medicine that had been in existence for over 2,000 years.

Almost four decades later, acupuncture is one of the alternative medicine techniques that is most recognized and most researched in the world. It has the strongest scientific foundation in the laboratory and an expanding body of clinical trial evidence. Chiropractic education now incorporates acupuncture training routinely, and The American Academy of Medical Acupuncture now has over 1,800 physician members [15].

What is acupuncture? The broadest definition of acupuncture is that it is the ­stimulation of specific points on the body to achieve a therapeutic effect. A more elaborated definition that puts it in a meaningful context would describe acupuncture as a component of Traditional Chinese Medicine (TCM), rooted in Taoist philosophy, involving stimulation at specific points on the body which lie along channels or meridians. A vital energy known as Chi is purported to flow within the channels. When disease occurs, the flow of chi is accelerated or blocked. Acupuncture regulates the flow and restores balance and health.

How was acupuncture discovered? Acupuncture is ancient. There is written documentation of acupuncture practice dating to around 600 BC—even before the availability of iron and steel for fashioning needles. It is unknown whether acupuncture points and technique were derived empirically or by some other means. See the historical timeline for a summary of acupuncture history [15] (Fig. 8.1).

Acupuncture technique. Needles are generally made of stainless steel, but are sometimes gold or silver to achieve energizing or sedating effects. Twenty-eight to thirty-two gauge solid needles are used. The length of the needle and depth of penetration depends on the thickness of the underlying soft tissue. Many acupuncture points overlie muscle and the depth of needle insertion is usually to the center of the muscle belly. Needles may be inserted perpendicularly, obliquely or tangentially. The acupuncturist usually tries to elicit a special needling sensation called deqi, which refers to a deep, heavy, warm, spreading or aching sensation that is felt to be crucial to achieve a therapeutic effect.

Stimulation of the acupuncture points is a necessary part of treatment. Needles may be stimulated in a variety of ways: manually, by thrusting up and down or twisting back and forth or by tapping or scraping the handle of the needle. Electrical current can be applied to pairs of needles at frequencies of 3–5 Hz or higher frequencies in the 100 or 1,000 Hz range. The amplitude of stimulation is adjusted to patient tolerance. Needles and acupuncture points may also be heated in various ways including the use of moxa, a plant that is burned near the acupuncture point or on the needle—a technique known as moxibustion.

The duration of an acupuncture session is about 20–45 min. The frequency of sessions is variable, depending on the clinical problem, its chronicity, and availability of resources. Typically, treatments are carried out once to three times per week. Sometimes treatments are offered daily or as infrequently as once or twice a month. A course of treatment consists of 10–20 sessions; but for intractable chronic conditions, periodic maintenance therapy may be offered. Ultimately, the intervals between treatments and the duration of a course of acupuncture remain empiric.

How are points chosen for treatment? There are two approaches: the Traditional Chinese Medicine approach and a formula approach. Traditional Chinese Medicine (TCM) uses a diagnostic system that is based on Taoist concepts of the natural order of the universe and life: Yin and Yang; the flow of vital energy, chi; and the relationships between the five elements that make up all things in the universe—fire, earth, metal, water, and wood. Human diseases are diagnosed in part by history; but the physical examination in TCM is quite different from that in Western Medicine. The appearance of the tongue and the qualities of the radial pulse are the primary physical assessment tools. In TCM, these physical attributes are elaborated to such an extent as to form a whole diagnostic system of medicine that is the basis for acupuncture point selection and treatment.

Equally acceptable, and commonly used in China and around the world, is a formula approach to point selection. It is based on some of the TCM concepts, but utilizes a limited number of basic rules for point selection:

What are the risks of acupuncture? Common side effects of acupuncture include syncope or near-syncope in less than 1% of patients (more likely if sitting up during the treatment), bruising around the needle site in about 2% of needle sticks, and persistent soreness from needling that outlasts the treatment by hours to days. We sometimes see a brief flare-up of a patient’s pain symptoms after the initial treatment and reduce the number of needles used or the amount of stimulation in subsequent sessions. Contact dermatitis has been reported and attributed to the nickel content in stainless steel needles. Acupuncture should be avoided during pregnancy or used with caution due to the apparent effect of uterine muscle contraction and cervical dilation that has been produced by stimulating certain points. Other risks of acupuncture can be divided in to organ or tissue damage and infections. The lung is the organ most likely to be injured during acupuncture. Several reports of unilateral and bilateral pneumothorax have emerged. Cases of spinal cord and peripheral nerve injuries have been associated with acupuncture due to migration of a broken needle fragment or a purposefully retained needle. Boxall reported 29 cases of serologically proven Hepatitis B traced to an acupuncture clinic in Birmingham, England. Four cases of hepatitis B were reported and traced to acupuncture treatment received at a chiropractic clinic in Florida in 1980. In both clinics poor needle management was used: reusable needles, use of hollow syringe-type needles, and unsterilized needles.

Clinical Studies. In one extensive multicenter randomized controlled trial of acupuncture, amitriptyline or placebo for HIV-related neuropathic pain, no differences were found between groups; but all groups showed significant reductions in pain [16]. Using an electro-acupuncture-like treatment, Hamza and colleagues showed a substantial reduction in pain scores and analgesic use and improvement in quality of life measures among patients with Type II diabetes and painful neuropathy in a sham-controlled crossover trial of 50 patients [17]. More recently, Schroeder et al. have reported on a pilot study of acupuncture compared with conventional treatment for chemotherapy-induced peripheral neuropathy. Those patients receiving acupuncture tended to show more improvement in nerve conduction studies than the control group [18]. Earlier, Schroeder had shown that acupuncture was effective at controlling pain and improving nerve conduction in idiopathic peripheral neuropathy [19]. In a randomized controlled trial of acupuncture for severe acute pain in herpes zoster, acupuncture was as effective as pharmacological treatment at controlling pain [20].