Dynamic ventrorostral displacement of the dorsal laryngeal mucosa in horses.

This study investigates a rare condition in horses called dynamic ventrorostral displacement of the dorsal laryngeal mucosa (VRDDLM), where the upper lining of the larynx shifts in a specific manner during strenuous exercise. The condition was detected in 12 out of 600 Thoroughbred horses undergoing endoscopic examination for performance issues or unusual respiratory noise, and associated with other respiratory abnormalities in eight of these horses.

Research Methodology

• The researchers conducted a retrospective review of records from 600 dynamic endoscopic examinations of the upper respiratory tract in horses.
• The examinations were performed on Thoroughbred horses that were presented due to poor performance and/or abnormal noise during respiration.
• Horses with VRDDLM were identified by a particular pattern of movement in the dorsal laryngeal mucosa, where the mucosa progressively blocked the interarytenoid notch and dorsoaxial portion of the corniculate processes of the arytenoid cartilages during high-speed exercise.

Results

• The condition VRDDLM was identified in 12 out of the 600 horses, marking it as a relatively rare abnormality in the equine respiratory tract.
• Among these 12 horses, the researchers also identified other concurrent abnormalities in the respiratory tract in eight horses. These included axial deviation of the aryepiglottic folds, vocal cord prolapse, unilateral and bilateral ventromedial luxation of the apex of the corniculate process of the arytenoid cartilage, and intermittent dorsal displacement of the soft palate.

Implications of the Findings and Future Research Directions

• The studied condition (VRDDLM) could potentially be the cause of abnormal respiratory noises and may also impact the performance of the horses.
• However, the significance and implications of this condition are not yet fully understood, calling for further research in this area.
• The condition often appearing alongside other respiratory diseases suggests that there could be a relationship or common underlying factor that needs to be investigated.