Overground endoscopic findings and respiratory sound analysis in horses with recurrent laryngeal neuropathy after unilateral laser ventriculocordectomy.

This research article investigates the effects of a surgical procedure, unilateral ventriculocordectomy, on horses suffering from a common nerve disorder, recurrent laryngeal neuropathy. The researchers analyzed the change in respiratory noise and throat health in the horses before and after surgery.

Methodology

• The study was conducted with client-owned horses that were clinically affected by recurrent laryngeal neuropathy.
• The horses underwent exercising endoscopy, a procedure in which a flexible tube fitted with a camera is inserted down the horse’s throat to get a clear look at the larynx. The endoscopy was performed while the horses were under sedation.
• At the same time, the horses’ respiratory noises were recorded.
• The horses then underwent a left-sided laser ventriculocordectomy, which is a surgical procedure to remove part of the vocal cord.
• The owners were asked to bring the horses back for re-examination six to eight weeks after surgery, at which time the endoscopy and sound recordings were repeated.
• The results were analyzed by measuring the change in the position and movement (LRQ and RGA), as well as the change in energy in the F1, F2, and F3 sound formants.

Results

• The study included three horses with grade B laryngeal function and seven horses with grade C function.
• Before the surgery, all the grade C horses and 5 out of 7 grade B horses were found to have abnormalities, including bilateral vocal fold collapse (VFC) and right-sided medial deviation of the ary-epiglottic fold (MDAF).
• After the surgery, it was found that these abnormalities were still present in the grade C horses, while the grade B horses had no other endoscopic dynamic abnormalities.
• The sound analysis showed significant reduction in energy in the F2 formant after surgery, which suggests improvement in the condition.

Conclusions

• The study had a small sample size and the multiple dynamic abnormalities in the horses made sound analysis challenging.
• Nonetheless, it was concluded that horses affected by recurrent laryngeal neuropathy experience reduction in sound levels in the F2 formant after undergoing unilateral laser ventriculocordectomy.
• Surgery was deemed beneficial for grade B horses, but for grade C horses, a different approach, possibly including bilateral ventriculocordectomy, right ary-epiglottic fold resection, and laryngoplasty, might be more suitable.