Some human and other mammalian studies have shown that extracorporeal shock wave therapy (ESWT) has adverse effects on vascular and nerve tissues, but this might not hold true for these structures in the horse. There have been some studies on ESWT’s effects on equine tendons and other large soft-tissue structures, but few studies have been done on the effects on vascular and nerve structures in the horse.

In a recent study presented at the 2006 American Association of Equine Practitioners convention in San Antonio, Texas, held Dec. 2-6, researchers used non-focused ESWT on the vascular bundles in the pasterns of one forelimb and one hind limb in each of five ponies. Adjacent vascular bundles were used as control areas. Each limb was treated with 2,000 pulses at a pressure of 2.5 bars and a frequency of 8 Hz. Scientists monitored the ponies for the following 24-hour period. Then they euthanatized the ponies and took samples of the treated areas.

“The results of this study suggest that non-focused ESWT (evaluated by gross examination and histopathology– microscopically–in adult ponies) does not have any appreciable anatomic or gross functional effect on the digital blood vessels in the short-term period,” explained Mauro Verna, DVM, MS, Dipl. ACVS, currently in Argentina, who performed this study with colleagues at the University of Minnesota.

Verna explained, “No gross evidence of skin ulceration was observed 24 hours post-treatment. Light microscopic examination did not reveal any evidence of clot formation, tissue damage, or infiltration of inflammatory cells in any of the tunics (thin membranous layers of tissue). No evidence of endothelial (lining of the vessels) swelling or detachment was noted in any of the treated or control slides.”

He said the difference between the human trials and the horse trials could be related to the different type of ESWT used (focused versus non-focused). However, he said larger studies are needed to better determine ESWT’s effect on vascular and nerve structures.

Get research and health news from the American Association of Equine Practitioners 2006 Convention in The Horse’s AAEP 2006 Wrap-Up sponsored by OCD Equine. Files are available as free PDF downloads