Electroacupuncture and Back Pain

Currently, much acupuncture practice in horses is based on limited evidence, such as small-scale research, case studies, and clinical experience. High-quality research is essential to the long-term development of "evidence-based practice." As there are few controlled studies on the effect of acupuncture on thoracolumbar (relating to the thoracic and lumbar portions of the vertebral column) pain in horses, Huisheng Xie, DVM, PhD; Patrick Colahan, DVM, Dipl. ACVS; and Edgar A. Ott, PhD, all of the University of Florida, performed a prospective study which was published in the Journal of the American Veterinary Medical Association (2005; 227:281-286) which compares electroacupuncture treatment of horses with signs of chronic thoracolumbar pain to treatment with phenylbutazone or treatment with saline.

Fifteen horses were randomly allocated to one of three treatment groups. Initially, four horses received electroacupuncture stimulation (Group 1), seven horses received phenylbutazone (Bute, Group 2), and four horses received saline solution (Group 3, the control group). After a washout period of four weeks, three horses randomly chosen from Group 3 (controls) and one horse randomly chosen from Group 2 (formerly receiving Bute) were reallocated to Group 1 for electroacupunture stimulation, and one horse randomly chosen from Group 3 (controls) was reallocated to Group 2 (receiving Bute). Overall, eight horses received electroacupuncture (four horses after the initial allocation and four additional horses that were reallocated), eight horses received Bute (seven horses after the initial allocation and one additional horse that was reallocated), and four horses received saline solution.

Thoracolumbar pain scores were determined for each horse by grading the behavior in response to continuous digital pressure (the examiner presses with their hands) moving from the thoracic region, through the lumbar, to the sacral region in three lines: on the dorsal midline from the withers to the base of the tail, on the muscular groove between the longissimus and iliocostalis muscles from the caudal (toward the rear) angle of the scapula to the lumbar region bilaterally, and on the depression which is 9 cm lateral to the second line bilaterally. The behavioral response was scored as follows: 0, no obvious aggressive or avoidance response; 1, local muscle contraction, lowering position of the thoracolumbar region, or avoidance response to pressure; 2, head shaking, tail wagging, and pawing the ground; or 3, violent avoidance response to pressure and kicking at the clinician. Thoracolumbar pain scores were evaluated before (baseline) and after each treatment by a blinded investigator.

Electroacupuncture was performed using four acupuncture points: Bai Hui (lumbosacral space), GV-6 (Duan Xue), BL-26 (Shen Shu), and BL-54 (Ba Shan). Each treatment was administered for 30 minutes (20 Hz for 15 minutes and 80 to 120 Hz for another 15 minutes).

Mean thoracolumbar pain scores in horses receiving Bute or saline solution did not change significantly during the study. After the third treatment, mean thoracolumbar pain scores in horses receiving electroacupuncture stimulation were significantly lower than baseline. This effect persisted 14 days after the last treatment.

Results of this study presented evidence that three sessions of electroacupuncture treatment can successfully alleviate signs of thoracolumbar pain in horses and the analgesic effect induced by electroacupuncture can persist for two weeks. Bute and saline did not effectively alleviate signs of thoracolumbar pain in horses.

All horses had signs of thoracolumbar pain of at least three months' duration and were chosen from clinical cases of horses with chronic signs of thoracolumbar pain evaluated at the University of Florida's Veterinary Medical Teaching Hospital (VMTH). Use of analgesic drugs was not permitted for a minimum of four weeks prior to the beginning of the study to avoid any confounding influences from these drugs. Criteria for diagnosis of thoracolumbar pain were based on history, physical examination findings, thoracolumbar pain scores, and negative scintigraphic (bone scan) results. Limb problems, including problems with tendons, ligaments, or joints, were ruled out by physical examination findings or responses to diagnostic nerve blocks and any affected horses were excluded from the study.

Owners and trainers of horses were unaware of treatment group allocation. Signs of thoracolumbar pain were evaluated and graded. The thoracolumbar pain scores were primarily based on behavioral responses. Because evaluation of behavior in horses can be subjective, all behaviors were recorded on videotape. The thoracolumbar pain scores were determined by obtaining the mean score of two investigations and evaluated by the same blinded investigator.

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