The surgery session at the American Association of Equine Practitioners (AAEP) convention covered a variety of subjects that ranged from using a laser to cauterize displaced soft palates to administering butorphanol for 24 hours to ameliorate pain in the wake of colic surgery.

The leadoff presenter was Patricia Hogan, VMD, Dipl. ACVS, from New Jersey Equine Clinic. Intermittent dorsal displacement of the soft palate (DDSP) during exercise, she told her listeners, is an important performance-limiting problem in the racehorse. In the past, the condition has been treated surgically, which, in one procedure called staphlectomy, involves removal of a portion of the soft palate. However, it was theorized that because flaccidity (lacking firmness) of the soft palate can be a contributing factor, the ability to change the character of the soft palate to create fibrosis without removing any of the substance might be a treatment of choice. A laser was utilized to cauterize the soft palate, rather than remove a portion of it.

Involved in the study were 42 Standardbred and 10 Thoroughbred racehorses, all of which had a history of exercise intolerance that was diagnosed by the referring veterinarians as involving the soft palate. Forty-six of the horses were reported to have audible upper respiratory noise detected at or near the end of a race, breeze, or training mile. The laser treatment, considered to be adjunctive therapy, was combined with a surgical procedure known as sternothyroideus tenectomy (SST)--removal of a portion of a muscle that is involved with control of the epiglottis and larynx--in 42 of the horses. Eight of them had already undergone this procedure at an earlier date, so only the laser was utilized, and for two of them only the laser treatment was advised because a definitive diagnosis for DDSP was lacking. Fifty of the 52 horses raced after surgery, and in 46 of the cases, the trainers reported that there was a decrease in or cessation of upper respiratory noise. 

In the Standardbred population of the study, there was a significant improvement in the fourth quarter racing times after surgery. This was considered to be a subjective indicator that DDSP was not occurring. Also, more than 90% of the horses which had experienced ulceration of the soft palate before surgery (an indication that DDSP is occurring at speed) had completely resolved the ulcerations after surgery--another subjective indicator that DDSP was not occurring during exercise. No complications from the laser treatment were reported.

Roaring in Drafts
Beth M. Kraus, DVM, University of Pennsylvania, reported on surgery to solve the problem of laryngeal hemiplegia or roaring in the draft horse. The draft horse is at an increased risk for the development of anesthetic complications, she said, and little information concerning the use of the surgical procedure on them is available.

To learn more about how draft horses reacted to the surgery, medical records and postoperative endoscopy were reviewed of draft horses which had been treated at New Bolton Center between 1992 and 2000. All of the horses were competitive hitch horses where the noise from "roaring" is not permitted in the show ring.

Involved in the study were 104 horses. Follow-up information was available on 86 of the draft horses. Of that number, 82% showed improvement. This compares to about 69% improvement when the procedure is performed on racehorses.

Kraus concluded that the higher success rate in draft horses could be because they do not perform as strenuously as racehorses. She concluded that the surgical procedure is effective for draft horses.

Lesions of the Nose
Lloyd Tate Jr., VMD, Dipl. ACVS, reported on new perspectives on diagnosis and treatment of ethmoid hematomas. Involved are lesions in the caudal or back part of the nostril near the sinuses.

The most consistent clinical sign of the condition, he said, is a bloody discharge from one or both nostrils. The problem with some of the established treatment protocols involves recurrence rates in the range of 20-50%. Treating the lesions with a laser, he reported, prevented recurrence in 80% of the cases. However, he added, no treatment is 100% effective in preventing recurrence.

Problems in the Jaw
H. David Moll, DVM, MS, Dipl. ACVS, of Oklahoma State University, presented a paper on "A Review of Conditions of the Equine Tempormandibular Joint (TMJ)." The joint in question involves the point where the lower jaw attaches to the skull.

TMJ conditions in horses, he said, might be overlooked because of the nonspecific nature of the clinical signs. These signs include dysphasia (difficulty in swallowing) due to chewing problems, malocclusion, localized pain, decreased range of motion of the lower jaw, and fistulous tract formation.

One of the best diagnostic tools, he said, is computed tomographic (CT) imaging.
Treatment of conditions of the TMJ, he said, normally would be similar to treatment of other joints in the horse. Arthroscopic surgery also might be useful in the diagnosis and treatment of conditions of the TMJ.

Pain After Colic Surgery
Debra Sellon, DVM, PhD, Dipl. ACVIM, of Washington State University, reported on the effect of using continuous butorphanol to reduce pain in postoperative colic cases. The drug was administered intravenously as part of the fluid therapy for 24 hours after colic surgery. She said that horses treated in that manner had improved recovery characteristics over horses which were only administered banamine.

The study, she said, was a joint effort between North Carolina State University, where she previously was located, and Washington State.

Plates in Cannon Fractures
Christopher Beinlich, DVM, MS, of Cornell University, reported on the results of plate fixation of front and rear cannon bone fractures. He studied case records from The Ohio State University between 1970 and 1986 and from the Rood and Riddle Equine Hospital from 1987 to 2000.

Sixty-three horses were studied. Of that number, 33 were treated with one plate and 30 were treated with two plates. Twenty-four horses were also placed in casts.

It was found he said that if the fractures were rated as being axially stable (i.e, spiraling condylar fractures), the survival rate was 100%; but only 53% of them were able to return to competition. When the fracture was rated as being axially unstable, the survival rate dropped to 77% with return to performance unknown.

Meniscal Injuries
Mary Beth Whitcomb, DVM, University of California, Davis, reported on a study of equine meniscal injuries in 14 horses. The meniscus is the cartilaginous tissue that prevents bones in the stifle joint from coming into contact with each other.

She concluded that meniscal injuries should be suspected in horses with severe hind limb lameness with prominent stifle effusion (the leakage of fluid into the joint) and arthritic changes affecting one side of the stifle joint based on X rays.

Ultrasonographic evaluation of the stifle joint should be performed in such cases to rule out meniscal or other soft tissue injury, she said. Ultrasound provides a reliable, non-invasive diagnostic modality for the diagnosis of equine meniscal injuries.

About the Author

Les Sellnow

Les Sellnow is a free-lance writer based near Riverton, Wyo. He specializes in articles on equine research, and operates a ranch where he raises horses and livestock. He has authored several fiction and non-fiction books, including Understanding Equine Lameness and Understanding The Young Horse, published by Eclipse Press and available at www.exclusivelyequine.com or by calling 800/582-5604.

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