34th Annual Scientific Meeting proceedings

Objectives:

The primary objective was to evaluate structural and functional abnormalities in dysphagic horses following prosthetic laryngoplasty, using a combination of normograde (NST) and retrograde endoscopic (RST) swallowing tests, and comparing results with those from healthy horses. A secondary objective was to demonstrate how this technique enabled the selection of an etiologic treatment and improved clinical outcome.

Methods:

Five healthy horses without a history of laryngeal pathology underwent combined NST and RST using a standard flexible endoscope introduced via tracheostomy or a needle arthroscopy with the head in various positions. Endoscopic findings were assessed and standardised. Twenty-six client-owned horses with post-laryngoplasty dysphagia, evaluated between 2019 and 2024, underwent assessment using this technique. Endoscopic images were recorded and reviewed in slow motion by two observers, and findings were compared with normal images

Results:

The RST was well tolerated by both normal and dysphagic horses. The most common finding during swallowing was epiglottic left retroversion (ELR) which led to dorsal leakage of food material (N=16; 62%). This finding was undetectable using the NST. Ventral leakage due to vocal remnant retraction (VRR) was the second leading cause of dysphagia (N=4; 15%) and was partially detectable with NST. Combined ELR and VRR were observed in 6 horses (23%).Treatment involved repeat laryngoplasty, vocal cord augmentation, or a combination of both. At six weeks post-operatively, 80% of horses showed improvement.

Conclusions:

The combination of NST and RST proved useful for detecting structural and functional causes of post-laryngoplasty dysphagia and for selecting an appropriate etiologic treatment.