Conducting a Double Blind Study of Acupuncture Therapy for Chronic Lameness in Horses
Janet Steiss DVM, PhD
Scott-Ritchey Research Centre
College of Veterinary Medicine
Auburn University AL 36849, USA
International Veterinary Acupuncture Society (IVAS) 25th Annual Congress,
Lexington, KY, USA, September 1999
There is good documentation of analgesic effects of acupuncture (AP) stimulation in many experiments on acute pain in laboratory animals. However, very few publications substantiate beneficial effects of AP in the treatment of spontaneously occurring diseases of domestic animals. Of those that have been published in the veterinary literature, most if not all have methodological problems. My PhD dissertation was conducted in the late 1970's at the University of Georgia, College of Veterinary Medicine. As part of my thesis, I undertook a controlled trial to evaluate the possible beneficial effects of AP on horses suffering from chronic lameness due either to navicular disease or laminitis. Although many aspects of the study were designed appropriately, the results were inconclusive. The abstract of that project, which was published (Steiss JE, White NA, Bowen JM. Electroacupuncture in the treatment of chronic lameness in horses and ponies: A controlled clinical trial. Canadian Journal of Veterinary Research 53:239-243, 1989), summarises the results:
Abstract: Electroacupuncture (EAP) was used to treat lameness in horses and ponies with chronic laminitis (n=10) or navicular disease (n=10). A clinical trail was conducted with random allocation of equal numbers of animals to control and treatment groups. EAP was performed three times per week for four consecutive weeks. The degree of lameness was assessed by (1) a grading scheme, (2) measurement of stride lengths, and (3) analysis of weight distribution using a force plate. Although 7/10 animals with chronic laminitis improved clinically during the trial, differences between treatment and control groups were not statistically significant. Of horses with navicular disease, 6/10 improved, but differences between treatment and control groups were not significant.
Advantages in the design of this study were:
- After admission to the study, animals were assigned randomly to control and treatment groups.
- The untreated control group had the same number of animals as the treatment group.
- The diagnoses were definitive, based on radiographs, diagnostic nerve blocks, etc.
- Animals with other concurrent illness (which could alter treatment response) were excluded.
- Several evaluations were used, including objective measures (stride length and force plate analysis) as well as a 6-point grading scheme for lameness, all of which could be statistically analysed.
- One experienced equine clinician graded the subjective lameness, thereby eliminating issues of inter-rater reliability. That person was blinded as to which animals were being treated.
Disadvantages in the design of this study were:
- There were no data to predict responses to therapy from any previous pilot study.
- The natural course of each lameness was not fully understood.
- The control groups showed improvement despite being lame >6 months.
- The lameness in the navicular control group had a cyclic pattern.
- Over the 4-week period, the laminitis controls progressively improved clinically. This spontaneous recovery in controls was unexpected, but underlines the importance of not having subjects serve as their own controls.
- Sample size (the number of animals/group) was too small to yield meaningful statistical results.
- Sample size was necessarily small because of the difficulty of finding a larger number of animals that would meet the admission criteria within a fixed time period, and because of funding limitations.
- No certified veterinary acupuncturist was available nearby.