Surgery for DDSP

Dorsal displacement of the soft palate (DDSP) occurs when the palate partially obstructs the airway by becoming displaced on top of the epiglottis. This can affect breathing, especially during intense exercise. Jennifer Smith, DVM, University of Pennsylvania's New Bolton Center, discussed the combined effects of the surgeries sternothyroideus myotomy, modified staphylectomy, and soft palate thermoplasty in Thoroughbred racehorses affected with DDSP.

Staphylectomy involves surgically resecting a small portion of the caudal edge of the soft palate. Sternothyroideus myotomy involves cutting the sternothyroideus muscle. During soft palate thermoplasty, a carbon dioxide laser is used to make several parallel lines through the oral mucosa (mucous membrane) and the submucosa along the caudal edge of the soft palate, which creates a large area of fibrosis and stiffens the palate.

In a study of horses treated for DDSP at Rood and Riddle Equine Hospital in Kentucky over a four-year period using the combination surgery, lifetime race records were reviewed on 73 of the horses. It was found that 46 (63%) which raced at least once before and after surgery improved their performance based on an increase in mean earnings per start. The mean time before return to racing after surgery was 109 days. (See article #4965 online.)

Roarers Race After Surgery

Research from New Bolton Center suggests 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). Eric Parente, DVM, Dipl. ACVS, of New Bolton Center, said the study found that horses which had undergone a failed laryngoplasty, or those with arytenoid chondritis, might have success with 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 them out of the airway. An arytenoidectomy is the removal of all or a portion of the arytenoid cartilages. "Partial arytenoidectomy has traditionally been associated with a poor prognosis for return to racing and a high postoperative complication rate," he said.

Of 66 horses in the study, 52 (79%) returned to racing after surgery, and 44 (67%) raced five or more times after surgery. Horses with bilateral lesions (33%) were less likely to return to racing than those with left (85%) and right (73%) lesions.

Complications such as dyspnea (difficulty breathing) and water coming out of the nose were not seen, said Parente. He said 11 horses which had granulation tissue within the larynx after surgery underwent endoscopic laser resection. He said previous reports might not have addressed this post-surgical complication. (See article #4964 online.)

Acute and Chronic Hind Limb Pain

Musculoskeletal pain associated with hind limb injuries is common in equine practice, said Laurie Goodrich, DVM, MS, Dipl. ACVS, of Cornell University. She discussed a pain management technique developed at Cornell that involves administering a combination of the opioids morphine and detomidine given epidurally (in the spinal canal).

"Unabated pain can result in complications such as gastrointestinal disorders and supporting limb laminitis," she said. "Motor function is not affected. Long-term epidural catheterization is not associated with adverse systemic effects." (See article #4960 online.)

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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