Transendoscopic laser treatment of rostral displacement of the palatopharyngeal arch in four horses

Objective: To document the use and clinical outcome of transendoscopic lase r techniques for treatment of rostral displacement of the palatopharyngeal arch (RDPA) in horses, Summary Background Data: Rostral displacement of the palatopharyngeal arch is a rare cause of upper respiratory noise and exerc ise intolerance in horses, and may be associated with abnormal laryngeal an atomy, There are few reports of successful treatment of this condition, and no reports of the treatment of RDPA using laser techniques, Methods: The d iagnosis of RDPA was based on the presence of palatal tissue covering the d orsal aspect of the arytenoid cartilages on endoscopic examination, Either a neodymium:yttrium aluminum garnet (Nd:YAG) laser noncontact technique (10 60 nm, 100 W continuous mode) or a diode laser contact technique (808 nm, 1 4 W, continuous mode) was used, Results: In 3 horses in which the Nd:YAG la ser was used, displaced palatal tissue was not fully divided at surgery, bu t separated after latent thermal necrosis within 3 days, In the horse in wh ich the diode laser was used, tissues were fully divided at the time of sur gery, Two horses had abnormal laryngeal anatomy and laryngeal hemiplegia, O ne of these 2 horses was subjected to arytenoidectomy, and had limited succ ess as a racehorse, while the other was retired as a broodmare, One of 2 ho rses with no other laryngeal abnormalities raced once unsuccessfully, while the other horse was never raced, Conclusions: Rostral displacement of the palatopharyngeal arch may be corrected in standing horses using transendosc opic surgery, but despite successful ablation of displaced tissue the progn osis for athletic performance is poor.