CHAPTER 198 Integrative Medicine: Applications of Acupuncture
Over the past several decades, performance demands on equine athletes in racing, eventing, and endurance have greatly increased. Therefore, most equine acupuncturists have responded by focusing their practice of traditional Chinese medicine (TCM) on management of chronic musculoskeletal pain and injuries.
Acupuncture is one of the oldest and most common forms of therapeutic intervention in the world. Although debate exists regarding the origin of acupuncture, widespread views often date the roots of this procedure back at least 2500 years. Acupuncture made its “debut” in the United States in 1971 following a New York Times report documenting how doctors in China used needles to ease pain in patients following abdominal surgery. Acupuncture has subsequently grown in popularity in the United States in both human and veterinary medicine.
In a 1998 Harvard University study it was estimated that Americans made more than 5 million visits per year to acupuncture practitioners. A 2002 National Health survey, the most comprehensive complementary and alternative medicine (CAM) study to date, estimated that 8.2 million U.S. adults had used acupuncture. A survey of members of the American Association of Equine Practitioners indicated that acupuncture referrals rose from 37% in 1998 to 56.4% in 2002, suggesting that owners and trainers are increasingly seeking CAM for treatment of chronic musculoskeletal pain and injury in their horses. This concept is also supported by the growing number of studies investigating CAM in both human and veterinary medicine. The National Institutes of Health has increasingly funded research projects on acupuncture through the National Center for Complementary and Alternative Medicine. In response to both the increased interest and growth in CAM, many U.S. medical schools and several veterinary schools have created CAM curricula and academic departments of alternative medicine.
Nonetheless, the question remains: does acupuncture work? A recent NIH consensus statement on acupuncture concluded that there have been many studies on acupuncture’s potential usefulness, yet results have been mixed, primarily because of complexities and inherent challenges with study design and size, along with difficulties in choosing placebos or “sham” acupuncture. However, promising results have emerged. A 2000 study published in the Journal of the American Medical Association revealed the efficacy of acupuncture in alleviating postoperative nausea and nausea and vomiting associated with chemotherapy in adults. Another recent study funded by NCCAM, the longest and largest randomized, controlled phase III clinical trial of acupuncture ever conducted, was published in the December 2004 issue of the Annals of Internal Medicine. This study demonstrated that acupuncture reduces the pain and functional impairment of osteoarthritis of the knee in humans. Although there are an increasing number of studies investigating CAM in veterinary medicine, results are often equivocal or contradictory and not sufficiently compelling to recommend or reject acupuncture as a treatment option in domestic animals.
A small number of randomized controlled equine clinical trials have been performed. Electroacupuncture was demonstrated to decrease thoracolumbar pain scores. Chronic thoracolumbar pain was successfully alleviated in three sessions of electroacupuncture treatment, with analgesic effect lasting at least 2 weeks. In comparison, phenylbutazone did not effectively alleviate signs of thoracolumbar pain in horses in that study. Equine and canine studies have also demonstrated some benefit of electroacupuncture in producing rectal analgesia. In contrast, other studies have found no significant benefit of acupuncture for treatment of recurrent airway obstruction, duodenal distension, laminitis, and navicular disease, or diagnosis of equine herpesvirus infection. Similar conflicting results are reported in the veterinary literature pertaining to dogs, with decreased emesis, sedation, increased gastric motility, and decreased colonic motility reported as effects of electroacupuncture. No significant benefit was reported in dogs with chronic elbow joint osteoarthritis secondary to elbow joint dysplasia.
One of the primary advantages of acupuncture is that the incidence of adverse effects is substantially lower than that of many drugs or other accepted medical procedures used for similar conditions. For example, painful musculoskeletal conditions, including osteoarthritis, are often treated with nonsteroidal anti-inflammatory drugs (NSAIDs) or corticosteroids. Pharmacologic management of these conditions is often ineffective and may result in unwanted or deleterious side effects. Despite the absence of compelling evidence-based–supported proof of efficacy of acupuncture in pain management, accumulated literature suggests acupuncture as a potentially useful option. Acupuncture may be beneficial in the treatment of many of these conditions and should be part of a comprehensive medical management program. Overall the integrative approach to medicine—incorporating the technology and solid orthodoxy of western medicine along with basic principles of TCM and eastern medicine—is an ideal method of diagnosis and treatment of many equine disorders. Regardless of the clinician’s approach, it is important to maintain and observe the perspective of seeing the relationship of the sign or signs to the entire body.
In the gate control theory, the experience of pain (nociception) depends on a complex interplay of pain messages originating in nerves (nociceptors) associated with the damaged tissue and conductance via peripheral nerves to the spinal cord and on up to the brain. Before impulses reach the brain, these messages encounter “nerve gates” in the spinal cord that open, allowing signal transduction, or close, blocking signal transduction, depending on a number of factors. At least two types of afferent nerve fibers are thought to carry most pain messages to the spinal cord: small, myelinated, fast (15 m per second) A-δ nerve fibers, and unmyelinated, slow, (1 m per second) C-fibers. Activation of other types of nerve fibers can modify or block the sensation of pain by overriding pain messages carried by the A-δ and C-fibers. Treatments such as massage, heat, cold, transcutaneous nerve stimulation, or acupuncture can ameliorate a pain message by influencing interactions between nerve fiber transmissions.
Compelling evidence supports the claim that a cascade of endorphins and monoamines is released during acupuncture and at least in part explains the analgesic and anti-nociceptive effects of acupuncture. This hypothesis is further strengthened by the fact that the opioid antagonist naloxone reverses the analgesic effects of acupuncture. Stimulation by acupuncture needles may also activate the hypothalamus and the pituitary gland, resulting in systemic effects such as secretion of neurotransmitters and neurohormones, changes in regulation of blood flow, and alterations in immune functions.