Clinicopathologic observations on laryngoplasty failure in a horse

Abstract

Objective: To report morphologic findings associated with laryngoplasty failure in a horse.

Study design: Clinical report.

Animals: A 9-year-old Thoroughbred cross gelding.

Methods: Necropsy and histopathology were performed on a horse that died peracutely during anesthetic recovery after correction of a right dorsal displacement of the ascending colon. Three weeks earlier the horse had left laryngoplasty and ventriculocordectomy.

Results: Dissection of the larynx revealed that the laryngoplasty suture had pulled through the muscular process of the left arytenoid cartilage, which appeared grossly normal. Histopathology of the arytenoid muscular process revealed cartilage necrosis, granulation tissue, and inflammation around the cartilage and within the cartilage failure line, and small numbers of coccoid bacteria in a minority of cartilage canals. Multifocal cardiomyopathy and pulmonary congestion, edema, and hemorrhage were also observed histologically.

Conclusion: Death was attributed to peracute pulmonary edema associated with cardiac abnormalities and airway obstruction from laryngoplasty failure. Morphologic changes in the muscular process indicate gradual progression toward laryngoplasty failure, possibly associated with suture-induced pressure necrosis and/or microscopic low-grade postoperative infection.