Influence of unilateral and bilateral vocal cordectomy on airflow across cadaveric equine larynges at different Rakestraw grades of arytenoid abduction

Abstract

Objective: To assess the effect of vocal cordectomy on airflow across equine larynges at different Rakestraw grades of arytenoid abduction using a unidirectional airflow model. Study design: Ex vivo, repeated measures. Sample population: Twenty cadaveric equine larynges. Methods: The right arytenoid cartilage was maximally abducted in all larynges. Each larynx was assigned a Rakestraw grade A or B, and the left arytenoid was abducted accordingly. Each larynx was tested under 3 conditions: intact, left vocal cordectomy (LVC), and bilateral vocal cordectomy (BVC). Translaryngeal pressure and airflow were measured, and digital video footage was obtained. Translaryngeal impedance (TLI) was calculated, and the arytenoid left-to-right quotient angle (LRQ) and rima glottis cross-sectional area (CSA) were measured from standardized still images. Results: Vocal cordectomy reduced TLI by 14.5% in LVC in comparison with intact larynges at Rakestraw grade B (P =.014). In Rakestraw grade A position, neither unilateral nor bilateral vocal cordectomy had any effect on TLI. Regardless of Rakestraw allocation, both LVC and BVC increased CSA in comparison with intact larynges (P