Influence of unilateral and bilateral vocal cordectomy on airflow across cadaveric equine larynges at different Rakestraw grades of arytenoid abduction.
Authors: Lean Natasha E, Bertin Francois R, Ahern Benjamin J
Journal: Veterinary surgery : VS
Summary
# Vocal Cordectomy and Equine Airway Flow: Does Arytenoid Position Matter? Recurrent laryngeal neuropathy (RLN) management in horses often involves vocal cordectomy to improve airflow, yet evidence supporting this approach remains limited. Researchers examined 20 cadaveric equine larynges using a unidirectional airflow model to determine whether removing vocal cord tissue actually reduces resistance to airflow and whether the degree of arytenoid abduction (classified by Rakestraw grade) influences outcomes. Unilateral vocal cordectomy reduced translaryngeal impedance by 14.5% only in larynges positioned at Rakestraw grade B, whilst at grade A it produced no measurable improvement in flow resistance; bilateral cordectomy increased the glottal opening cross-sectional area in both grades but failed to reduce impedance at grade A. These findings suggest that vocal cordectomy's aerodynamic benefit depends critically on baseline arytenoid positioning—a sobering reminder that grade B horses may genuinely benefit from cordectomy, but grade A cases (often the most severely affected) may gain no functional airway advantage from the procedure, warranting reconsideration of surgical planning and patient selection criteria.
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Practical Takeaways
- •Pre-operative assessment of arytenoid abduction position (Rakestraw grading) should guide surgical decision-making for vocal cordectomy—the procedure only improves airflow in grade B cases
- •Vocal cordectomy expands the glottic opening but this benefit is limited to horses with adequate baseline arytenoid abduction; in poorly abducted larynges (grade A), the procedure provides no functional airflow advantage
- •Consider whether post-operative gains in glottic area translate to clinically meaningful performance improvement, especially in grade A cases where airflow mechanics are unchanged
Key Findings
- •Unilateral vocal cordectomy (LVC) reduced translaryngeal impedance by 14.5% in Rakestraw grade B larynges but had no effect in grade A larynges
- •Both LVC and BVC significantly increased rima glottis cross-sectional area regardless of Rakestraw grade, with bilateral cordectomy producing greater effect than unilateral
- •Arytenoid abduction grade is a critical determinant of whether vocal cordectomy will improve airflow mechanics
- •Surgeons should assess arytenoid position before performing vocal cordectomy as the procedure may not improve airflow in grade A positions