Chapter 92Acupuncture

Equine Acupuncture for Lameness Diagnosis and Treatment

Interest in veterinary acupuncture for lameness diagnosis and treatment has increased greatly in the public and veterinary medical communities. With this increased awareness has come an increase in veterinary acupuncture research and thus a better understanding of the physiological basis of acupuncture and its clinical applications. Acupuncture may be used as an adjunct diagnostic and therapeutic tool to our traditional lameness examination and to the treatment of lameness, but it is not meant to be a substitute.

With the increased interest in equine acupuncture, there has also been additional controversy and use and misuse of this modality. It is important to understand the scientific basis, traditional Chinese medical theories, and clinical indications and limitations if acupuncture is to be used in a professional manner as part of an integrated approach to equine lameness. Currently, equine acupuncture is practiced by veterinarians trained in the Western medical perspective of scientific acupuncture and the traditional Chinese and Japanese medical theories. The approach may vary slightly based on the practitioner’s perspective.

The history of equine acupuncture dates back to 2000 to 3000 bce during the Shang and Chow dynasties in China. Around 650 bce Bai-le wrote Bai-le’s Canon of Veterinary Medicine, one of the first veterinary textbooks, which described acupuncture and moxibustion in equine medicine. The first atlas of equine acupuncture points and channels, Ma Jing Kong-xiue Tu, was written during the Sui period, from 581 to 618 ce.¹ Equine back pain was first addressed in the ancient veterinary textbook Yuan-Heng Liao Ma Ji (Yuan-Heng’s Therapeutic Treatise of Horses).² Periodically, anecdotal reports of using equine acupuncture would come to the Western world. The first substantial introduction occurred in the 1970s, when the International Veterinary Acupuncture Society was established and developed training programs in veterinary acupuncture in the United States. In 1996 the American Veterinary Medical Association stated, “Veterinary acupuncture and acutherapy are considered valid modalities, but the potential for abuse exists. These techniques should be regarded as surgical and/or medical procedures under state practice acts. It is recommended that extensive continuing education programs be undertaken before a veterinarian is considered competent to practice acupuncture.”³ Postgraduate education in veterinary acupuncture throughout the world—including Australia, Europe, Scandinavia, North and South America, and other areas—is offered by the International Veterinary Acupuncture Society, based in Fort Collins, Colorado.⁴ The Chi Institute of Traditional Chinese Medicine in Reddick, Florida⁵; Colorado State University College of Veterinary Medicine continuing education program in Fort Collins, Colorado⁶; Tufts University School of Veterinary Medicine in North Grafton, Massachusetts⁷; and the Veterinary Institute for Therapeutic Alternatives in Sherman, Connecticut⁸ also offer postgraduate programs. All of the programs are in the United States.

Scientific Basis

Acupuncture may be defined in a Western medical perspective as the stimulation of specific predetermined points on the body to achieve a therapeutic or homeostatic effect. Recent research has provided evidence for the anatomical classification of acupoints. Acupuncture points are areas on the skin of decreased electrical resistance or increased electrical conductivity. Acupuncture points correspond to four known neural structures. Type I acupoints, which make up 67% of all acupoints, are considered motor points. The motor point is the point in a muscle that, when electrical stimulation is applied, will produce a maximal contraction with minimal intensity of stimulation. Motor points are located near the point where the nerve enters the muscle. Type II acupoints are located on the superficial nerves in the sagittal plane on the midline dorsally and ventrally. Type III acupoints are located at high-density foci of superficial nerves and nerve plexuses. For instance, acupoint GB-34 is located at the point where the common fibular (peroneal) nerve divides into the deep and superficial branches. Type IV acupoints are located at the muscle-tendon junctions, where the Golgi tendon organ is located.⁹ Recently, histological studies have revealed that small microtubules, consisting of free nerve endings, arterioles, and venules, penetrate through the fascia at acupuncture points (Figure 92-1).¹⁰

Fig. 92-1 Schematic drawing of the skin, showing a neurovascular bundle wrapped by a sleeve of loose connective tissue deep to an acupoint.

(From Schoen AM, ed: Veterinary acupuncture: ancient art to modern medicine, ed 2, St Louis, 2001, Mosby.)

Acupuncture has many varied physiological effects on all systems throughout the body. No one mechanism can explain all the physiological effects observed. Traditional Chinese medical theories have explained these effects for 4000 years, based on empirical observations and descriptions of naturally occurring phenomena. Western medical theories include the gate and multiple gate theories, autonomic theories, humeral mechanisms, and bioelectric theories.¹⁰ Detailed discussions of the neurophysiological basis of acupuncture are reviewed in a number of texts.^9-12 Essentially, acupuncture stimulates various sensory receptors (pain, thermal, pressure, and touch), which stimulate sensory afferent nerves, which transmit the signal through the central nervous system to the hypothalamic-pituitary system (Figure 92-2). The acupoints correlate with cutaneous areas containing higher concentrations of free sensory nerve endings, mast cells, lymphatics, capillaries, and venules. Various neurotransmitters and neurohormones are then released and have subsequent effects throughout the body. Research in rabbits using electroacupuncture-induced neural activation, detected by the use of manganese-enhanced functional magnetic resonance imaging, demonstrated a corresponding cerebral link between peripheral acupoints and central neural pathways. Research such as this is aiding in further understanding the effects of local peripheral stimulation on specific areas in the brain.¹³ Electroacupuncture has also been found to stimulate endogenous opioids, vasoactive peptides, adrenocorticotrophic hormone, cortisol, and catecholamine in cerebrospinal fluid and peripheral plasma in ponies.¹⁴ Bossut and colleagues¹⁵ documented changes in plasma cortisol and β-endorphin in horses subjected to electroacupuncture for cutaneous analgesia. Changes in serum protein and blood gas concentrations also have been demonstrated in donkeys after acupuncture.^16,17 Xie and colleagues¹⁸ documented that electroacupuncture could relieve experimental pain in the horse via the release of β-endorphin. They found that acupuncture stimulation using local acupuncture points with high frequency (80 to 120 Hz) is more effective than using distal points with low frequency (20 Hz). They found that acupoints close to the painful areas require high-frequency electroacupuncture stimulation, whereas the acupoints far from the painful areas may be stimulated with low-frequency electroacupuncture. Electroacupuncture generally is considered to have stronger effects than other types of acupuncture methods.¹⁸ The degree of stimulation appears to depend on the location of the specific acupoints.^19,20