Return to Racing for Roarers After Surgery

Results of a study from the University of Pennsylvania's New Bolton Center suggest that there is a high chance that a horse can return to racing after surgery for laryngeal hemiplegia (partial or complete paralysis of the larynx, also called roaring) or arytenoid chondritis (inflammation of the arytenoid cartilages resulting in paralysis). Presented by Eric Parente, DVM, Dipl. ACVS, of New Bolton Center, at the 2003 American Association of Equine Practitioners' convention, the study found that horses which had undergone a failed laryngoplasty, or those with arytenoid chondritis, might have success after undergoing a partial arytenoidectomy (removal of most of the arytenoid cartilage).

Laryngoplasty involves placing a large suture(s) on the outside of the laryngeal cartilages in order to pull the arytenoids out of the airway. By stabilizing the cartilage out of the airway, dynamic collapse of the cartilage is prevented. An arytenoidectomy is the removal of all or a portion of the arytenoid cartilage on one or both sides of the throat. It has typically been reserved for horses in which laryngoplasty has failed. It is also performed in horses with arytenoid chondritis or other abnormalities of the arytenoid cartilages. This procedure requires the use of a tracheostomy (surgically creating an opening into the trachea), bypassing the throat as a route to administer anesthetic gas, thus allowing room for the surgeon in the throat.

"Partial arytenoidectomy has traditionally been associated with a poor prognosis for return to racing and a high postoperative complication rate," said Parente. "The authors (of the study) have had a different experience and thought that the prognosis may be better than previous reports indicated."

Medical records for 69 horses which underwent partial arytenoidectomy after a previously failed laryngoplasty or for arytenoids chondritis from 1992 to 2002 were evaluated for the study. Three horses were excluded due to other medical problems that prevented discharge from the clinic, resulting in 66 horses used in the final analysis. All of the horses had the affected arytenoid removed. Any granulating (kissing) lesions on the opposite arytenoid were also removed. Out of 69 horses, 22 horses were treated for laryngeal hemiplegia and 47 were treated for arytenoid chondritis.

Post-surgical care included administration of oral phenylbutazone (Bute) and oral trimethoprim sulphamethoxazole. The horses had a small tracheotomy tube for at least one day. The incision sites were cleaned daily. The horses were kept on stall rest for one month before re-evaluation, then were turned out for a second month before resuming exercise, said Parente.

The average time to the first start was six months after surgery, with the time ranging from two months to 20 months. The average number of starts after surgery was seven.

Of 66 horses, 52 (80%) returned to racing after surgery, and 44 (67%) raced five or more times after surgery. Parente found that geldings were more likely to return to racing (96%) and race five or more times (96%). Horses with bilateral lesions (33%) were less likely to return to racing than those with left (85%) and right (73%) lesions. This did not reach statistical significance, but only because of the small number of horses treated bilaterally.

Complications such as dyspnea (difficulty or labored breathing) and water coming out of the nose were not seen, said Parente.

He credited the higher success rate to several factors. One was that the horses with bilateral lesions only underwent surgery to remove one side, if the remaining arytenoids could still maintain a good opening. Kissing lesions were removed with the laser.

Parente said that a more careful dissection to remove as much extraneous (nonessential) mucosa (mucous membrane) as possible was done to limit the amount of upper respiratory obstruction after surgery. This mucosal obstruction has previously been noted as a complication after this type of surgery. In order to minimize another common complication, aspiration of food and water, Parente said that careful dissection to remove the entire cartilage and minimize trauma to adjacent muscles might have reduced the risk of aspiration problems. Parente also pointed out that 11 horses which had granulation tissue within the larynx after surgery underwent endoscopic laser resection after the partial arytenoidectomy. He said that previous reports might not have addressed this post-surgical complication.

For more information on laryngeal hemiplegia, arytenoid chondritis, and its treatments, see "Roaring Down the Stretch."

About the Author

Sarah Evers Conrad

Sarah Evers Conrad has a bachelor’s of arts in journalism and equine science from Western Kentucky University. As a lifelong horse lover and equestrian, Conrad started her career at The Horse: Your Guide to Equine Health Care magazine. She has also worked for the United States Equestrian Federation as the managing editor of Equestrian magazine and director of e-communications and served as content manager/travel writer for a Caribbean travel agency. When she isn’t freelancing, Conrad spends her free time enjoying her family, reading, practicing photography, traveling, crocheting, and being around animals in her Lexington, Kentucky, home.

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