Excision of Intralaryngeal Granulation Tissue in 25 Horses Using a Neodymium:YAG Laser (1986 to 1991)

Abstract

Granulation tissue masses arising from the axial surface of the arytenoid cartilage in 25 horses were excised using a contact neodymium:yttrium aluminum garnet laser. A technique that eliminated the need for general anesthesia or laryngotomy was developed for transen-doscopic removal of the masses in standing horses. Nineteen racehorses made abnormal upper respiratory tract noises or their performance was decreased, whereas six horses not used for racing had a history of stertor (five horses) or epistaxis after nasogastric intubation (one horse). Thoroughbreds were significantly (p = .0126) overrepresented compared with the hospital population. The granulation tissue masses were successfully excised and the defect healed in all 25 horses, although a second excision of granulation tissue regrowth was necessary in four horses. In 21 horses, the underlying chondrosis did not progress appreciably. In four horses with preexisting moderate arytenoid cartilage thickening and concurrent laryngeal abnormalities, the surgery site healed but the underlying chondrosis progressed substantially. Twelve of 19 (63%) racehorses returned to race at least three times after the surgery. Of the 19 racehorses, five had only slight arytenoid cartilage involvement whereas 14 had moderate cartilage thickening or concurrent laryngeal pathology. All five horses with slight apparent arytenoid cartilage involvement and no concurrent laryngeal pathology returned to racing. Seven of the 14 horses (50%) with moderate underlying cartilage thickening or concurrent laryngeal pathology returned to racing. The six horses not used for racing returned to their previous activity without further respiratory problems.

Idiopathic mucosal lesions of the arytenoid cartilages of 21 Thoroughbred yearlings: 1997–2001

“…Purchase of horses affected with granuloma of the arytenoid cartilage should be considered carefully, because a granulomatous mass arising from the axial surface of one or both of the arytenoid cartilages may result in partial exercise intolerance, even when the underlying cartilage has normal structure and function (Hay and Tulleners 1993). Endoscopic confirmation of cartilaginous disease beneath a mucosal ulcer or granuloma is difficult in the absence of grossly detectable cartilaginous enlargement.…”

“…and phenylbutazone (2.2 mg/kg bwt, per os, b.i.d.). Exuberant tissue was trimmed to the level of the mucosal surface transendoscopically with a diode laser (Diomed 25 25W S u rg i c a l l a s e r ) 2 , performed as described previously (Hay and Tulleners 1993), with the horse standing and sedated and the larynx anaesthetised with topically applied local anaesthetic solution. The mucosal defect was seen to have healed 4 weeks after surg e r y, but the area beneath the defect appeared to be slightly thickened.…”

“…Reported diseases of the arytenoid cartilage include chondritis (Haynes et al 1980); chondroma (Trotter et al 1981); hypertrophic ossification (Shapiro et al 1979); intralaryngeal granulomas (Hay and Tulleners 1993;Stick et al 1999); small reddened areas of unknown significance on the corniculate process or adjacent to the vocal process (Embertson 1998); and small vesicles and ulceration on the medial aspect of the cartilage (Arthur 1990).…”

Self-Assessment

“…Arytenoid granulomas can be excised surgically by scalpel via a laryngotomy or with the use of a laser trans-endoscopically, as performed in this case. Approximately 65% of cases treated with laser excision require only one treatment (Hay & Tulleners, 1993). Recurrence of granulation tissue can be treated with repeat laser excision, or, if the lesion extends to involve the arytenoid cartilage, arytenoidectomy.…”

Endoscopic electrosurgical excision of laryngeal granulation tissue in a standing pregnant mare

“…It has been suggested that laryngeal trauma and mucosal damage may initiate the problem (Haynes and others 1980), and granulation tissue formation has been reported after laryngotomy and intraluminal surgery of the equine larynx (Haynes 1978). Other possible causes in racehorses include intralaryngeal trauma secondary to the inhalation of track debris, and concussive and abrasive forces between the arytenoids (Hay and Tulleners 1993).…”