Dynamic respiratory videoendoscopy in ridden sport horses: effect of head flexion, riding and airway inflammation in 129 cases.

The study investigates how rider interaction, head flexion, and airway inflammation can cause dynamic obstruction in a horse’s upper airway during exercise. The paper recommends overground endoscopy as the best method for evaluation since these changes wouldn’t normally be detected with treadmill videoendoscopy.

Research Methods

The research involved video recordings of 129 sport horses both at rest and during exercise. The reasons for referrals were generally due to concerns about respiratory noise, suboptimal performance, or for routine evaluation.

• The researchers encouraged the rider to adjust poll flexion (the angle of the horse’s head and neck) and their riding style during exercise, recording any changes in upper airway obstruction (UAO).
• The study also assessed inflammation state in both the upper and lower airways of the horses.

Results

Researchers found the occurrence of UAO in:

• 91% of horses referred due to respiratory noise,
• 71% of horses referred due to poor performance.
• Pharyngeal instability (the instability of the horse’s throat) was the most common problem identified.
• Distinct differences were noted between dressage horses and showjumpers in terms of airway obstruction.

According to the study, rider interaction and head flexion increase upper airway instability and can lead to more complex cases of UAO. Both pharyngeal lymphoid hyperplasia (an overgrowth of lymphoid tissue in the horse’s throat) and lower airway inflammation were associated with pharyngeal instability, but no link was found with other types of UAO.

Conclusion

Findings suggest that the actions of the rider during exercise (such as asking the horse to carry out certain movements) can alter the anatomy and function of the horse’s upper respiratory tract. These changes could potentially conduce to increased instability in the larynx or pharynx. Importantly, these changes may not typically be identified with treadmill videoendoscopy. Consequently, the authors propose that overground videoendoscopy, performed while the horse is ridden, should be the preferred means for evaluating the upper airway in sport horses.