Use of videoendoscopy during exercise for determination of appropriate surgical treatment of laryngeal hemiplegia in a colt.

Videoendoscopy of the larynx during treadmill exercise was used to determine the surgical treatment of upper airway obstruction in a Standardbred colt. Surgical correction of right-sided laryngeal hemiplegia, first by laryngoplasty, then subtotal arytenoidectomy, was ineffective. Videoendoscopy indicated, and upper airway flow mechanics confirmed, that the laryngeal opening was adequate at rest, but obstruction occurred during exercise. On the basis of the appearance of the larynx during high airflow rates on slow-motion playback of the videorecording, total arytenoidectomy was performed, which permitted the horse to race successfully. Videoendoscopy of the upper airway during exercise accurately predicted airflow impedance and permitted salvage of this racehorse, indicating that this is a practical, useful technique that will improve evaluation of upper airway obstructions in the horse.