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