Retrospective study investigating causes of abnormal respiratory noise in horses following prosthetic laryngoplasty.

This research article examines potential causes for respiratory noises in horses after they’ve undergone a surgical procedure known as prosthetic laryngoplasty, and it specifically investigates if there is a correlation between the degree of arytenoid abduction and other abnormalities in the upper respiratory tract (URT).

Study Purpose and Methodology

• The purpose of this retrospective study was to explore causes of abnormal respiratory noises in horses once they’ve received prosthetic laryngoplasty, a surgery commonly executed on equines suffering from laryngeal hemiplegia (partial paralysis of the larynx).
• The study was further interested in discerning any relationships between the level of arytenoid abduction (an aspect of the surgery that pertains to the arytenoid cartilages’ displacement within the larynx) and any other present URT abnormalities, such as right-sided collapse.
• To accomplish this, the investigation examined clinical records and dynamic videoendoscopic recordings—from a span of 15 years—of horses who displayed respiratory noises during exercise post-laryngoplasty.

Study Findings

• Out of the 30 horses that met the criteria for this study, all had received previous prosthetic laryngoplasty surgery in different hospitals and, in 63% (19/30) of these cases, a left-sided ventriculocordectomy (another surgical procedure used to treat upper respiratory diseases in horses) had been done in addition.
• Majority of the equines (87%) were diagnosed with multiple respiratory abnormalities, with only 13% exhibiting a single disorder in the URT.
• Palatal dysfunction was the most commonly noted disorder (diagnosed in 83% of cases), followed by axial deviation of the aryepiglottic folds (60%) and vocal cord collapse (43%).
• There was no statistical correlation identified between the degree of left arytenoid abduction and any other URT disorders.
• Equally, horses with suboptimal left arytenoid cartilage abduction were not predisposed to experiencing right-sided laryngeal collapse.

Conclusion

• This retrospective study concluded that a variety of dynamic URT disorders were diagnosed in horses exhibiting unusual respiratory noises after a laryngoplasty surgery.
• No link was found between the degree of left arytenoid abduction and these incidents of URT abnormalities. This suggests that suboptimal left arytenoid cartilage abduction does not increase the risk for right-sided laryngeal collapse.
• The findings further underscored the importance of dynamic endoscopy—a diagnostic procedure involving the use of a flexible tube with a light and camera attached—for accurately diagnosing dynamic airway collapse in horses that have been surgically treated for URT issues.