Dynamic laryngeal collapse associated with poll flexion as a complication of laryngeal tie-forward surgery in three harness racehorses.
Authors: Vermedal Hanna, Strand Eric
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: Dynamic Laryngeal Collapse Following Laryngeal Tie-Forward Surgery Laryngeal tie-forward procedures (LTFP) are commonly performed in harness racehorses to address dorsal displacement of the soft palate, but Vermedal and Strand's 2020 case series reveals an important iatrogenic complication that may be significantly underdiagnosed in practice. Three standardbreds and Norwegian coldblooded trotters developed bilateral arytenoid cartilage and vocal fold collapse specifically when exercised in poll flexion (as occurs during driving with bit and reins), despite being clinically normal at liberty, highlighting a critical diagnostic limitation of conventional endoscopic evaluation. The condition appeared in three of 35 postoperative horses reviewed via high-speed treadmill videoendoscopy—a notably higher detection rate than would likely be found during routine resting or free-exercise examination. For practitioners managing ongoing upper airway obstruction in harness racehorses following LTFP, dynamic laryngeal collapse associated with poll flexion must be considered as a differential diagnosis, requiring assessment under ridden or driven conditions rather than resting evaluation alone. This work underscores the importance of position-specific airway examination and suggests that apparently unsuccessful LTFP outcomes warrant investigation during functional exercise mimicking actual racing conditions.
Read the full abstract on PubMed
Practical Takeaways
- •When harness racehorses continue to show respiratory signs after laryngeal tie-forward surgery, evaluate them specifically under working conditions (with bit/reins) rather than free lunging, as DLC may only manifest with poll flexion
- •Understand that normal appearance at rest or in free head carriage does not rule out post-surgical dynamic laryngeal collapse in these horses
- •Consider poll flexion mechanics as a risk factor when counselling clients on complications and expected outcomes of laryngeal tie-forward procedures
Key Findings
- •Three harness racehorses developed bilateral arytenoid cartilage and vocal fold collapse associated with poll flexion after laryngeal tie-forward procedure
- •Dynamic laryngeal collapse was only apparent during high-speed treadmill or overground videoendoscopy with bit and reins, not in free head carriage
- •This complication may be underdiagnosed because clinical signs are masked when horses are evaluated without poll flexion
- •Post-LTFP laryngeal collapse should be considered as a differential diagnosis in racehorses with persistent airway problems after surgery