Correlation of performance with endoscopic and radiographic assessment of epiglottic hypoplasia in racehorses with epiglottic entrapment corrected by use of contact neodymium:yttrium aluminum garnet laser

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Summary Epiglottic entrapment in 35 Thoroughbred and 44 Standardbred horses was corrected transendoscopically by use of a neodymium:yttrium aluminum garnet laser. Before surgery, the entrapped epiglottis was classified as hypoplastic or normal in each horse on the basis of endoscopic appearance alone. Using a digitizer, thyroepiglottic length was determined from lateral-view laryngeal radiographs. For 78 racehorses, earnings (<$5,000 or >$5,000) were compared before and after surgery. Earnings category and racing performance after surgery were tested for association with endoscopically determined epiglottic hypoplasia and radiographically determined thyroepiglottic length. Endoscopy and radiography were useful methods of evaluating the epiglottis in horses with epiglottic entrapment. Mean (±sd) thyroepiglottic length for both breeds of horses with epiglottic entrapment was significantly (P = 0.0001) smaller (Thoroughbreds, 7.28 ± 0.67 cm; Standardbreds, 7.21 ± 0.62 cm), compared with thyroepiglottic length measured from control groups composed of clinically normal Thoroughbred (8.56 ± 0.29 cm) and Standardbred (8.74 ± 0.38 cm) racehorses. Both breeds of horses with epiglottic entrapment that had endoscopically apparent hypoplastic epiglottis had significantly (P < 0.0001) smaller thyroepiglottic length (Thoroughbreds, 6.64 ± 0.60 cm; Standardbred, 6.93 ± 0.72 cm) than did horses with epiglottic entrapment that had endoscopically normal epiglottis (Thoroughbreds, 7.57 ± 0.47 cm, Standardbreds, 7.36 ± 0.50 cm). Significant difference was not detected in endoscopic appearance of the epiglottis among age, gender, or breed distributions. For either breed, earnings and performance were not significantly associated with endoscopically determined epiglottic hypoplasia or radiographically determined thyroepiglottic length. Prognosis for racing performance after laser correction of epiglottic entrapment should be based on assessment of the endoscopic and radiographic appearances of the epiglottis, pharynx, and larynx, determination of thyroepiglottic length, and a knowledge of the horse's earnings and racing performance prior to surgery.