Association of treadmill upper airway endoscopic evaluation with results of ultrasonography and resting upper airway endoscopic evaluation.
Authors: Garrett K S, Woodie J B, Embertson R M
Journal: Equine veterinary journal
Summary
# Editorial Summary Recurrent laryngeal neuropathy (RLN) remains a significant cause of poor performance in racehorses, yet diagnosis has traditionally relied on resting endoscopy, which may fail to detect subtle arytenoid dysfunction. Garrett and colleagues compared three diagnostic approaches—resting endoscopy, treadmill endoscopy and laryngeal ultrasonography—in Thoroughbreds to determine whether ultrasound could reliably identify abnormal arytenoid movement (AM) associated with RLN. Using treadmill endoscopy as their gold standard, they measured muscle echogenicity and cross-sectional area (CSA) of the left cricoarytenoideus lateralis and vocalis muscles via ultrasound, grading resting AM using established clinical scales. Laryngeal ultrasonography demonstrated significantly superior diagnostic accuracy, achieving 90% sensitivity and 98% specificity for detecting abnormal AM, compared to resting endoscopy's 80% sensitivity and 81% specificity; notably, horses with abnormal treadmill AM showed increased echogenicity of the affected left cricoarytenoideus lateralis muscle, though CSA measurements did not differ between groups. For practitioners managing performance-limiting upper airway disease, these findings suggest that laryngeal ultrasonography offers a non-invasive, highly accurate complementary tool that may detect RLN cases missed by traditional resting examination alone, potentially enabling earlier intervention before significant muscle atrophy or clinical decline occurs.
Read the full abstract on PubMed
Practical Takeaways
- •Laryngeal ultrasonography should be incorporated into diagnostic protocols for suspected recurrent laryngeal neuropathy, as it is more accurate than resting endoscopy alone
- •Hyperechogenicity on ultrasound of the left cricoarytenoideus lateralis muscle is a reliable indicator of abnormal arytenoid movement during exercise
- •Treadmill endoscopy remains the gold standard for assessment, but ultrasonography offers a non-exercise complementary diagnostic tool with high specificity to reduce false positives
Key Findings
- •Laryngeal ultrasonography achieved 90% sensitivity and 98% specificity for detecting abnormal arytenoid movement, compared to resting endoscopy at 80% and 81% respectively
- •Abnormal arytenoid movement was associated with relative hyperechogenicity of the left cricoarytenoideus lateralis muscle, while normal movement showed no such changes
- •Cross-sectional area of left cricoarytenoideus lateralis and vocalis muscles did not differ between horses with normal and abnormal arytenoid movement
- •Laryngeal ultrasonography demonstrated superior diagnostic accuracy to resting upper airway endoscopy for identifying abnormal arytenoid movement during exercise