Unilateral and bilateral compression of the epiglottis during poll flexion in harness racehorses

Abstract

Objectives: To describe a formerly unknown dynamic disorder of the epiglottis and to attempt to determine the pathogenesis and clinical relevance. Methods: Medical records of Standardbred trotters and Norwegian Coldblooded trotters referred to the Norwegian School of Veterinary Medicine for upper airway evaluation with high-speed treadmill endoscopy were reviewed. Results: 15 harness racehorses were diagnosed with unilateral or bilateral compression of the epiglottis during poll flexion. Harness racehorses, which are predisposed to this condition, demonstrate this disorder before the appearance of other dynamic airway disorders during the first period of induced poll flexion. In all cases, the compression of the epiglottis seemed to be due to inward pressure from the lateral pharyngeal wall and the thyrohyoid-thyroid cartilage articulation during periods of poll flexion. Conclusions: Compression of the epiglottis during poll flexion in harness racehorses is a primary upper airway disorder induced by poll flexion. At present date, there are no surgical treatments. The current recommendations are use of tack to limit the degree of poll flexion in these horses.