Videoendoscopic assessment of dynamic laryngeal function during exercise in horses with grade-III left laryngeal hemiparesis at rest: 26 cases (1992-1995)

Abstract

Objective To evaluate laryngeal function by means of videoendoscopy during high-speed treadmill exercise in racehorses with grade-III left laryngeal hemiparesis at rest and to determine outcome of treatment. Design Retrospective study. Animals 26 racehorses. Procedure Videoendoscopy of the larynx was performed while horses were at rest and exercising on a treadmill. Horses were classified as having grade-III A, -IIIB, or -IIIC laryngeal hemiparesis on the basis of the degree of arytenoid cartilage abduction maintained during exercise. Postoperative racing performance was determined by evaluating race records and conducting telephone surveys. Results 20 (77%) horses had grade-IIIC laryngeal hemiparesis (ie, severe dynamic laryngeal collapse during exercise). Eighteen underwent surgery, and racing performance was improved in 9. Five (19%) horses had grade-IIIB laryngeal hemiparesis (ie, left arytenoid cartilage and vocal fold were maintained in an incompletely abducted position during exercise). Four underwent surgery, and racing performance was improved in 1. One (4%) horse had grade-IIIA laryngeal hemiparesis (ie, full abduction of arytenoid cartilage during exercise); surgery was not performed. Clinical Implications Videoendoscopy is useful in determining dynamic laryngeal function in racehorses with grade-III laryngeal hemiparesis at rest. ( J Am Vet Med Assoc 1998; 212:399-403)