Long-term exercising video-endoscopic examination of the upper airway following laryngoplasty surgery: a prospective cross-sectional study of 41 horses.

This research study investigates how successful laryngoplasty surgery is in horses over a long-term period, using video endoscopy during exercise. The results show that despite most owners believing the surgery to be beneficial, large numbers of the horses continued to have upper airway abnormalities.

Study Design

• The study aimed to assess the long-term function of the upper respiratory tract of horses that have previously undergone laryngoplasty (LP). Laryngoplasty is a surgical procedure performed to correct upper airway obstructions in horses.
• The horses were put through an exercise regime that was deemed maximal for their particular discipline. During the exercise, the horses’ respiratory tracts were analyzed using over-ground endoscope equipment. Videos of the larynx and pharynx were taken both at rest and during exercise.
• The research sought to evaluate the horses’ arytenoid abduction (opening of the larynx) and stability, identify any concurrent respiratory issues, and relate these findings to horse owners’ perceptions of the surgery’s success.

Results

• A total of 41 horses were included in the study conducted over a 6-year period. Surprisingly, 78% of the horses exhibited some form of upper airway collapse during exercise, and 41% showed complex forms of collapse.
• However, 93% of the horse owners reported that they perceived the surgical procedure as beneficial.
• The statistical analysis revealed that horses with poor arytenoid abduction were six times more likely to produce respiratory noise versus those with good abduction. Moreover, horses that did not undergo ventriculectomy (removal of the ventricle of larynx) were almost five times more likely to produce respiratory noise after surgery.
• About 24% of horses demonstrated palatal dysfunction (improper functioning of the palate) at rest, and 56% had palatal dysfunction during exercise, showing a strong correlation between the two conditions.
• Increasing severity of a condition known as pharyngeal lymphoid hyperplasia was significantly associated with increased arytenoid abduction.

Conclusions

• Despite the surgery being seen as beneficial by most horse owners, the study found that many horses continue to show upper airway abnormalities post-surgery.
• The findings suggest that when investigating cases of ongoing respiratory noise or poor performance following laryngoplasty, it would be prudent to employ exercising endoscopy.
• The evidence also indicates that persistent respiratory noise may be linked with poor arytenoid abduction and a lack of concurrent ventriculectomy during the laryngoplasty surgery.