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  • Writer's pictureDr Michael Porter DVM

Left and right laryngeal hemiplegia in a horse.

The endoscopic images below are from two different horses with similar clinical complaints yet slightly different physical problems. The gelding in Figure 1 presented for significant respiratory noise during the canter (roaring) and resistance when cantering to the right. The gelding was 12 years old and had a history of "roaring" for multiple years.  In Figure 1, it is evident that there is complete paralysis of the left arytenoid process. Under exercise, the paralyzed process tended to cross over mid-line and prevent adequate passage of air.  He was referred to a surgical facility and a "tie back" procedure was performed. Thirty day post-op endoscopy revealed near complete abduction of the left arytenoid (Figure 2)!! The gelding is significantly improved and will likely perform at a higher level than that prior to surgery.

Figure 1: Left arytenoid hemiplegia in a horse.

Figure 2: "Roarer" post tie-back surgery in a horse.

The endoscopic images in Figure 3 and 4 were from a gelding that presented for significant exercise intolerance at the canter in either direction. The initial endoscopic exam revealed complete paralysis of the right arytenoid process (Figure 3). Paralysis of the right arytenoid is much less common than paralysis of the left arytenoid process and is associated with a worse prognosis. Consultation with an equine surgeon determined that the gelding was NOT a candidate for a "tie back" procedure. In an attempt to improve the gelding's airway, a surgical ablation of several components of the larynx was performed. The thirty day post-op endoscopy revealed a significantly improved airway (Figure 4). Prognosis for this horse as a sport horse remains to be determined however his quality of life has significantly improved! These two cases demonstrate the importance of acquiring the correct diagnosis and surgical intervention via an experienced and highly skilled equine surgeon!! Thank you Dr. John Madison (Ocala Equine Hospital)

Figure 3: Right arytenoid hemiplegia in a horse.

Figure 4: Right arytenoid hemiplegia post surgery in a horse.

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