Rostral displacement of the palatopharyngeal arch in a seven-month-old Hanoverian colt

Cricopharyngeal-laryngeal dysplasia in a horse with sudden clinical onset idiopathic laryngeal hemiparesis

A 7-year-old Thoroughbred racehorse developed loud exercise-related respiratory noises and exercise intolerance over a short period. Examination showed congenital cricopharyngeal-laryngeal dysplasia (rostral displacement of the palatopharyngeal arch) and also left sided idiopathic laryngeal hemiparesis, the latter appearing to be of recent clinical onset. The animal developed colic some months after laryngeal surgery and a nephrosplenic entrapment was surgically corrected. Aerophagia and regurgitation worsened after surgery and, after developing inhalation pneumonia, the animal was destroyed. Post-mortem examination confirmed the presence of idiopathic laryngeal hemiparesis and of cricopharyngeal-laryngeal dysplasia which had some previously undescribed laryngeal muscle abnormalities.

Disorders of the pharynx

Pharyngeal disorders are complex and difficult to treat. Disorders that lead to anatomic derangement, such as trauma and neoplasia, can significantly affect the function of this organ. Pharyngeal dysfunction can manifest as dysphagia, persistent palatal displacement, or exercise intolerance. Secondary complications are serious and life threatening and include aspiration pneumonia, weight loss, and death. Pharyngeal disorders that are only recognizable during strenuous exercise are difficult to diagnose and are treated with limited success, even though they are responsible for significant economic losses with performance animals.

History, Instrumentation, and Techniques of Flexible Endoscopic Laser Surgery in Horses

There are clearly a number of applications for which flexible endoscopic laser surgery has become the state of the art in equine surgery, and the Nd:YAG laser seems to be the most versatile instrument for this type of surgery. Nevertheless, it is critical to understand the advantages and disadvantages of each laser technique. For example, the Nd:YAG laser used in a noncontact fashion seems to be superior when ablation of tissue is required such as treatment of upper airway masses. Conversely, contact Nd:YAG laser techniques have proven themselves to be superior when more precise cutting is advantageous such as treatment of epiglottic entrapment. Ultimately, it seems that a range of lasers is necessary to ensure selection of the most appropriate technique, adding significantly to the expense of equipment but improving the outcome for a range of equine diseases.

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

OBJECTIVE

To document the use and clinical outcome of transendoscopic laser 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 exercise intolerance in horses, and may be associated with abnormal laryngeal anatomy. There are few reports of successful treatment of this condition, and no reports of the treatment of RDPA using laser techniques.

METHODS

The diagnosis of RDPA was based on the presence of palatal tissue covering the dorsal aspect of the arytenoid cartilages on endoscopic examination. Either a neodymium:yttrium aluminum garnet (Nd:YAG) laser noncontact technique (1060 nm, 100 W continuous mode) or a diode laser contact technique (808 nm, 14 W, continuous mode) was used.

RESULTS

In 3 horses in which the Nd:YAG laser was used, displaced palatal tissue was not fully divided at surgery, but separated after latent thermal necrosis within 3 days. In the horse in which the diode laser was used, tissues were fully divided at the time of surgery. Two horses had abnormal laryngeal anatomy and laryngeal hemiplegia. One of these 2 horses was subjected to arytenoidectomy, and had limited success as a race-horse, while the other was retired as a broodmare. One of 2 horses 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 transendoscopic surgery, but despite successful ablation of displaced tissue the prognosis for athletic performance is poor.