Functional electrical stimulation as a safe and effective treatment for equine epaxial muscle spasms: Clinical evaluations and histochemical morphometry of mitochondria in muscle biopsies

Functional Electrical Stimulation (FES) is used to reverse muscle atrophy during rehabilitation. The technology is expanding into other areas, and FES is utilized for injury rehabilitation and performance enhancement in horses. The study confirms that FES is effective and safe in reducing chronic muscle spasms in the top line of horses. Clinical evaluation found epaxial muscle spasms in all horses with minimal to no pelvic extension when manually palpated. FES treatments were performed on the sacral/lumbar region 3 times per week for a period of 8 weeks, obtaining a total of 22 treatments per horse. The Modified Ashworth Scale for grading muscle spasms found a one grade improvement after approximately four FES treatments, indicating improved functional movement of the sacral/lumbar region, supporting the evidence by clinical palpations that a reduction in epaxial muscle spasms occurred.

• 1
  Only a couple of horses showed significant increases in mean muscle fiber size when Pre- vs Post-FES biopsies were compared, as expected for the FES treatment used.
• 2
  Older horses had atrophic and angulated muscle fibers in both Pre- and Post-FES samples, suggesting denervation due to distal neuropathy.
• 3
  Preliminary data indicate an increased density and distribution of mitochondria in Post-FES biopsies, suggesting clinical improvements may be related to increased muscle contraction and perfusion induced by FES training.