Upper airway dysfunction associated with collapse of the apex of the corniculate process of the left arytenoid cartilage during exercise in 15 horses.
Authors: Dart Andrew J, Dowling Bradley A, Smith Christine L
Journal: Veterinary surgery : VS
Summary
# Editorial Summary: Corniculate Process Collapse as an Upper Airway Abnormality Between 1998 and 2003, Dart and colleagues identified a previously unreported dynamic upper airway obstruction in 15 of 309 horses (4.9%) presenting with poor performance and respiratory noise during exercise. Using high-speed treadmill videoendoscopy, they documented progressive collapse of the left corniculate process of the arytenoid cartilage folding under the right cartilage and into the airway during inspiration, a mechanism that appeared to compromise the dorsal rima glottidis and was often accompanied by secondary collapse of the left aryepiglottic and vocal folds. The affected horses were predominantly young males (aged 2–5 years), and notably, five had previous surgical interventions for left recurrent laryngeal neuropathy (nerve muscle pedicle grafts or laryngeal prostheses), suggesting a possible pathophysiological link to adductor denervation. The authors hypothesise that weakness of the left arytenoideus transversus muscle—potentially related to advanced left recurrent laryngeal neuropathy—permits the elastic corniculate cartilage to collapse inward under the negative inspiratory pressures of exercise, though the precise aetiology remains unclear. Clinicians evaluating racehorses and performance animals with unexplained exercise intolerance or respiratory noise should remain alert to this condition, as it is only definitively diagnosed during high-speed videoendoscopy and may significantly compromise athletic capacity if unidentified.
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Practical Takeaways
- •This uncommon upper airway problem can only be diagnosed using high-speed treadmill videoendoscopy—standard endoscopy at rest will miss it.
- •Affected horses are predominantly young males (2-5 years) in racing disciplines; consider this diagnosis in Thoroughbreds and Standardbreds with poor performance or respiratory noise that fail other diagnostic workups.
- •The condition may develop after previous laryngeal surgery for RLN, suggesting a possible link to advanced adductor nerve involvement requiring further investigation.
Key Findings
- •Dynamic collapse of the left corniculate process apex occurred in 15 of 309 horses (4.9%) referred for upper airway evaluation.
- •All affected horses showed progressive collapse of the left corniculate process under the right during high-speed treadmill videoendoscopy, followed by collapse of the left aryepiglottic and vocal folds.
- •Five horses had previous surgery for left recurrent laryngeal neuropathy (2 nerve-muscle pedicle grafts, 3 laryngeal prostheses).
- •The condition may represent an unusual manifestation of advanced recurrent laryngeal nerve neuropathy, though pathogenesis remains unclear.