Outcome analysis of 95 harness racehorses with confirmed dorsal displacement of the soft palate treated with laryngeal tie-forward surgery.

Abstract

The laryngeal tie-forward (LTF) procedure is commonly used to treat intermittent dorsal displacement of the soft palate (iDDSP). There is a wide range in reported efficacy of treating horses with and without a definitive diagnosis of iDDSP. To evaluate the racing performance of harness racehorses in which iDDSP had been definitely diagnosed and treated solely with the LTF procedure. Retrospective case series. Ninety-five harness racehorses were treated with LTF for confirmed iDDSP. A definite diagnosis of iDDSP was made with high-speed treadmill or overground endoscopy. Upper respiratory tract (URT) disorders, short-term complications, and horses returning for recurrence of URT problems were recorded. Performance before and after LTF was assessed by reviewing career race records and comparing performance index (PI), and racing speed marks from the baseline, preoperative, and postoperative periods. The effect of basihyoid-cricoid (BC) net distance shortened on racing performance was assessed. Postoperatively, PI increased in 36/54 (67%, 95% CI 54%-79%) of experienced racehorses, and 44/67 (66%, 54%-77%) established or improved their racing speed mark relative to the preoperative period. As a group, PI decreased by a mean (SE) of 0.9 (0.17) points (P<.001) prior to diagnosis/surgery. Postoperatively, PI increased by 0.5 (0.16) points (P=.003), and racing speed improved by 0.83 (0.22)s (P<.001). Twenty-five percent (17%-34%) and 49% (39%-60%) of horses did not demonstrate a decline in PI and racing speed prior to diagnosis, respectively. Net BC distance shortening did not affect performance postoperatively. Twenty of 95 horses (21%, 13%-29%) had confirmed recurrence of iDDSP 46-708days postoperatively. Not all horses were evaluated with exercising endoscopy postoperatively. Racehorses inevitably develop other racing-related problems which confound studies of this nature. This study provides scientific support for the use of LTF to treat iDDSP in harness racehorses although iDDSP seems to affect harness racehorses differently as individuals.