Surgery to correct "roaring" in National Hunt Thoroughbred racehorses can restore racing performance to levels similar to a matched group of peers in the short term, but career longevity appears to be negatively impacted following these procedures, report a team of UK researchers led by Safia Barakzai, BVSc, MSc, DESTS, Dipl ECVS, from the Royal (Dick) School of Veterinary Studies at the University of Edinburgh, Scotland.

"Roaring" is caused by dysfunction of the left recurrent laryngeal nerve, resulting in either partial or complete paralysis of the left arytenoid cartilage. Subsequently, the affected left cartilage droops into the lumen of the larynx where it obstructs the flow of air. The treatment of choice is laryngoplasty (i.e., "tie-back" surgery), which involves placing one or more sutures (stitches) to abduct the anomalous arytenoid cartilage, rendering the laryngeal lumen permanently open on one side.

"Compared to Thoroughbreds that race on the flat, National Hunt Thoroughbreds run over longer distances (2-4.5 miles) and also jump hurdles or fences," Barakzai explained.

Because the efficacy of laryngoplasty in National Hunt horses was not known, Barakzai and colleagues analyzed race records for 63 National Hunt Thoroughbreds and 126 race-matched controls to evaluate the effect of laryngoplasty and ventriculocordectomy (removal of the left vocal cord and saccule) on short- and long-term racing performance