A comparison of laryngoplasty and modified partial arytenoidectomy as treatments for laryngeal hemiplegia in exercising horses.
Authors: Radcliffe Catherine H, Woodie J Brett, Hackett Richard P, Ainsworth Dorothy M, Erb Hollis N, Mitchell Lisa M, Soderholm L Vince, Ducharme Norm G
Journal: Veterinary surgery : VS
Summary
# Laryngeal Hemiplegia Treatment: Laryngoplasty versus Modified Partial Arytenoidectomy Left laryngeal hemiplegia (recurrent laryngeal neuropathy) causes severe airway obstruction during exercise, and two surgical approaches—laryngoplasty with vocal cordectomy (LPVC) and modified partial arytenoidectomy (MPA)—are commonly used to restore function, yet direct comparison of their physiological outcomes remained limited. This study used six horses with experimentally induced laryngeal hemiplegia, measuring airway mechanics, arterial blood gases, and airway contamination under both procedures at 80% and 100% of maximal heart rate. At moderate exercise intensity (80% HR max), both procedures restored most variables to normal, though MPA preserved bicarbonate levels better than LPVC; at maximal intensity (100% HR max), neither fully restored minute ventilation, arterial pH, and carbon dioxide levels to baseline, despite improving all measured variables compared with the paralysed state. For practitioners, these findings indicate that both LPVC and MPA perform equivalently for sub-maximal work, with clinically negligible differences at maximal effort, meaning surgical choice can be guided by factors such as surgeon expertise, cost, and post-operative recovery expectations rather than superior physiological outcomes—though practitioners should counsel owners that neither procedure completely restores normal upper airway function during all-out exercise.
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Practical Takeaways
- •For sport horses working at typical intensities (sub-maximal), both LPVC and MPA are functionally equivalent—procedure choice can be based on surgeon preference, cost, or horse anatomy rather than expected outcome differences.
- •Understand that neither procedure fully restores normal airway function at peak exertion; horses may have residual performance limitations at maximal effort despite successful surgery.
- •Both procedures increase aspiration risk by compromising laryngeal protection during exercise, so monitor for respiratory signs post-operatively and manage exercise resumption carefully.
Key Findings
- •Both laryngoplasty/vocal cordectomy (LPVC) and modified partial arytenoidectomy (MPA) restored airway mechanics and blood gases to near-normal at 80% maximal heart rate, with only minor differences between procedures.
- •At 100% maximal heart rate, both procedures improved all variables but failed to fully restore minute ventilation, arterial pH, and PaCO₂ compared to control.
- •Both LPVC and MPA resulted in equivalent tracheal contamination post-exercise, indicating similar compromise of laryngeal protective mechanisms.
- •Sub-maximal exercise ventilation is normalized by either procedure, but maximal exercise performance remains compromised with slight superiority of LPVC over MPA.