Equine veterinary journal2013; 45(5); 593-597; doi: 10.1111/evj.12020

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

Barnett, TP
·
O'Leary, JM
·
Parkin, TD
·
Dixon, PM
·
Barakzai, SZ

Abstract: To investigate upper respiratory tract function in horses, previously undergoing laryngoplasty (LP), using exercising video-endoscopy. Objective: To evaluate arytenoid abduction and stability, diagnose any concurrent upper airway problems, and correlate these with the owners' perception of success. Methods: Horses undergoing LP during a 6-year period at one hospital were initially included. Those available for re-examination were exercised for a duration and intensity considered maximal for their discipline using an over-ground endoscope. Resting and exercising laryngeal and pharyngeal videos were analysed blindly. Multivariable analysis was used to test associations between resting and exercising endoscopic variables, and also between endoscopic variables and owner questionnaire findings. Results: Forty-one horses were included and 78% had a form of upper airway collapse at exercise, with 41% having complex forms, despite 93% of owners reporting the surgery to have been beneficial. Horses with poor abduction (grades 4 or 5/5) were 6 times more likely to make respiratory noise compared with those with good (grades 2 or 3/5) abduction (P = 0.020; 95% confidence interval [CI] 1.3-27.0), and those not having a ventriculectomy were 4.9 times more likely to produce respiratory noise post operatively (P = 0.048; 95% CI 1.0-23.9). Palatal dysfunction was observed in 24% of horses at rest, and 56% at exercise, with the diagnosis at rest and exercise significantly associated (P = 0.001). Increasing severity of pharyngeal lymphoid hyperplasia (prevalence 61%) was significantly associated with increasing arytenoid abduction (P = 0.01). Thirty-four per cent of horses had aryepiglottic fold collapse and 22% of horses had vocal fold collapse. Conclusions: Many horses that had previously had LP were diagnosed with upper airway abnormalities, despite the procedure being considered as beneficial by most owners. Conclusions: When investigating cases of ongoing respiratory noise or poor performance following LP, exercising endoscopy must be considered. Continued respiratory noise may be associated with poor arytenoid abduction and not performing concurrent ventriculectomy.

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Publication Date: 2013-01-29 PubMed ID: 23360315DOI: 10.1111/evj.12020Google Scholar: Lookup

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Summary

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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.

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APA

Barnett TP, O'Leary JM, Parkin TD, Dixon PM, Barakzai SZ. (2013). Long-term exercising video-endoscopic examination of the upper airway following laryngoplasty surgery: a prospective cross-sectional study of 41 horses. Equine Vet J, 45(5), 593-597. https://doi.org/10.1111/evj.12020