Dynamic respiratory endoscopic findings pre- and post laryngoplasty in Thoroughbred racehorses.

This study examines the changes in laryngeal function in racehorses suffering from recurrent laryngeal neuropathy, both before and after undergoing surgery, using dynamic respiratory endoscopy. Largely, the study discovers that while the surgery improves the laryngeal function, additional airway obstructions often occurred.

Methodology

• The study was designed as a prospective case series, including Thoroughbred racehorses which underwent the dynamic respiratory endoscopy (DRE) both before and after laryngoplasty surgery (commonly known as LP).
• Various aspects of laryngeal function, such as the ratio of left-to-right arytenoid cartilage angle and the rima glottidis area, were measured during both rest and exercise, before and after the surgery.

Findings

• The study found that pre-surgery values were greater during rest than exercise. Following the surgery, these values increased during exercise.
• A positive linear relationship was discovered between the post-surgery resting values and the post-surgery exercise values, indicating that the degree of airway opening at rest was useful in predicting the degree of the opening during exercise.
• All horses in the study showed signs of left arytenoid cartilage collapse along with bilateral vocal cord collapse before the surgery. Additionally, 37% of the horses also had an aryepiglottic fold collapse.
• The study reported that 37% of horses developed additional obstructions in their upper airway after the surgery. These horses showed smaller post-surgery rima glottidis area ratios than those that did not develop additional obstructions.

Conclusion

• The study concluded that multiple forms of dynamic upper airway obstruction (DUAO) occurred prior to laryngoplasty (LP) and additional forms often developed after the surgery.
• The evidence suggesting a positive correlation between post-surgery rest and exercise values may be useful for predicting the effectiveness of the surgery. This could help veterinary surgeons to predict complications following surgery, and to take preventive measures.