Unilateral laser ventriculocordectomy results in increased arytenoid stability in horses with severe left sided recurrent laryngeal neuropathy.

BACKGROUND: There is no objective information reporting the effect of unilateral laser ventriculocordectomy (VeC) on arytenoid abduction or stability.

OBJECTIVES: To evaluate arytenoid stability and abduction in horses with severe recurrent laryngeal neuropathy (RLN) before and after unilateral laser VeC.

STUDY DESIGN: Prospective cohort.

METHODS: Eight horses with grade C or D exercising laryngeal function that underwent unilateral laser VeC were included. Exercising endoscopy was performed before and ≥6 weeks after left-sided laser VeC. Arytenoid stability at maximal exercise was calculated by measuring the left-to-right quotient angle ratio (LRQ) of the corniculate processes at the points of maximal arytenoid abduction (expiration) and maximal arytenoid collapse (inspiration). For each horse, means of measurements obtained for four breaths pre- and post-operatively were used for statistical analysis.

RESULTS: The difference in LRQ between inspiration and expiration was lower post-operatively (median 0.039; interquartile range [IQR] 0.032-0.047) compared with pre-operatively (median 0.158; IQR 0.083-0.249; p = 0.01) confirming the left arytenoid was more stable following unilateral laser VeC. The degree of improvement was significantly greater for grade D horses compared with grade C horses (p = 0.04). The LRQ measured on maximal abduction was also lower post-operatively (median 0.467; IQR 0.444-0.506) compared with pre-operatively (median 0.578; IQR 0.554-0.655; p = 0.02) indicating the left arytenoid was less abducted following surgery.

MAIN LIMITATIONS: The sample size was small, no racehorses were included and post-operative assessment was conducted at a variable time after surgery.

CONCLUSION: Unilateral laser VeC in grade C and D RLN-affected horses results in slightly reduced left arytenoid abduction but increased arytenoid stability.