Surgical and conservative management of bilateral dynamic laryngeal collapse associated with poll flexion in harness race horses.

The research aimed to study the impact of bilateral ventriculocordectomy, a surgical procedure, on racehorses suffering from bilateral dynamic laryngeal collapse associated with poll flexion, a disorder that affects the horse’s upper respiratory tract and ultimately performance during races. The study concluded that the procedure was not significantly improving the horses’ performance or stabilizing other physical abnormalities in the larynx.

Research Methods

• The study was designed as a retrospective study, which implied the researchers examined the past medical records and other data relating to each horse’s condition.
• It involved 26 harness racehorses. The specific breed focused on were Norwegian Coldblooded Trotters (NCT), which were found to be overrepresented in those suffering from the disorder.
• What defined the disorder was simultaneous bilateral vocal fold collapse (VFC) and arytenoid cartilage collapse (ACC).
• The chosen horses had been admitted for high-speed treadmill videoendoscopy (HSTV), a diagnostic procedure to analyze their airways during a high-exertion state like racing.

Results

• Of the 26 horses, 16 underwent surgical treatment, the bilateral ventriculocordectomy, while the other ten were treated via conservative management methods.
• Based on race records, owner interviews and follow-up HSTV, the research found that the surgical procedure did not lead to significant improvement in racing performance or a return to racing within or between the groups that were treated.
• Follow-up HSTV on six of the horses that had the surgical treatment showed no remaining soft tissue collapse in the ventral part of the rima glottidis, a part of the animal’s larynx. However, ACC and other abnormalities were still evident.

Conclusion

• The study concluded that bilateral ventriculocordectomy solved the VFC issue but did not stabilize the arytenoid cartilages or significantly improve racing performance.
• It was also noted that bilateral dynamic laryngeal collapse associated with poll flexion is a significant performance-limiting upper respiratory tract disorder, particularly in NCT racehorses, and there is currently no consistently effective treatment method.
• The researchers suggest that VFC might not be the initial event causing this complicated obstructive airway disorder, contrary to what was hypothesized before the study.