Veterinarians and horse owners can share in a tremendous amount of knowledge from the AAEP Convention. While many of the topics on surgery were designed to help the practitioner learn new techniques and aren't applicable for the lay person, there are other topics that dealt with surgery and its uses that had a message for both veterinarian and client.

Periosteal Stripping Useful?

One of the more controversial presentations during a session on surgery was offered by Emma K. Read, DVM, of the University of Saskatchewan. Her topic dealt with periosteal stripping for young horses with angular limb deformities. (This is technically known as hemicircumferential periosteal transection and elevation.) Read had questioned whether the procedure was any more beneficial than conservative treatment with stall confinement and trimming.

At the University of Saskatchewan, a study involved taking 10 30-day-old foals, anesthetizing them, and placing a transphyseal bridge "at the distal lateral radial physis of each leg using a pair of 4.5-mm cortical screws and two strands of 1.2-mm wire" to induce angular deformity.

The foals were then confined in a large pen until significant angulation developed. When the limbs had reached 15 degrees of angulation or the foal was 90 days old, the implants were removed and treatment protocols were begun. Legs to be treated were selected at random, with some undergoing the stripping procedure and others being treated with stall rest and proper trimming.

Eight weeks after the treatment began, Read said, the angulation was significantly improved. However, there was no significant difference between limbs that had undergone periosteal stripping and those treated conservatively. Examination of the foals at one year of age showed no significant difference in angulation between limbs treated surgically and those treated conservatively.

Members of the audience challenged her conclusion, but Read held firmly to her conviction that surgery had not improved the outcome.

Patella Fixation

M. Aziz Tnibar, DVM, PhD, of Clinique Equine in Maisons-Alfort, France, reported on a technique that involved ligament splitting for the treatment of upward fixation of the patella. The horse's stifle can be compared to the human knee, and it is the animal's largest and most complex joint. When upward fixation of the patella occurs, the patellar ligaments, which hook over the knob of the femur to lock the stifle in extension, fail to unhook to allow the patella to slide downward and the leg to bend. As a result, a horse will drag the affected leg until the ligament unhooks.

Tnibar said his study involved splitting the upper third of the medial patellar ligament in an effort to foster thickening and strengthening of the ligament. The procedure was performed on four horses and three ponies, he said, and was successful in each instance. There were no complications from the surgery, and all of the animals were able to return to work soon after the surgery.

Stifle Trauma

Carolyn E. Arnold, DVM, of the University of Pennsylvania's New Bolton Center said stifle trauma can be a common cause of lameness in the horse. Fractures of the tibial tuberosity often occur as a result of direct trauma, such as hitting the stifle on a fence while jumping, or as an avulsion injury (tearing away of part of the structure) caused by slipping on ice. When a fracture is involved, surgery is a repair option, but Arnold said there are some inherent risks, especially during recovery from anesthesia.

The purpose of her study was to determine whether conservative treatment involving stall rest would be as successful as surgery. As part of her study, she examined the records of 15 horses admitted to New Bolton Center and treated conservatively for tibial tuberosity fracture. A follow-up survey revealed that 10 of the 15 horses had recovered and were performing at the previous or a higher athletic level at an average of 52 months after the injury.

Three of the 15 never returned to athletic capability due to protracted lameness. The other two horses in the group developed patellar desmitis.

In conclusion Arnold said, "The mortality rate associated with internal fixation (surgery) is as high as 50%. Implant failure and catastrophic fracture of the tibia were cited as the cause for failure.

"Although conservative management might require a more extended period of rehabilitation, the risk of mortality and prognosis for successful outcome are improved compared to surgical treatment," she continued. "Our results suggest conservative management of tibial tuberosity fractures to be an alternative method of treatment with favorable outcome."

Surgical Treatment of Uveitis

The owner of a horse with equine recurrent uveitis (ERU) doesn't have many options when it comes to long-term treatment and care. Two relatively new surgical procedures are available--intravitreal cyclosporine implants and core vitrectomies (CV). Brian C. Gilger, DVM, MS, Dipl. ACVO, Associate Professor of Ophthalmology at the North Carolina State University College of Veterinary Medicine, recently set out to review the literature and find the indications, complications, and long-term results. He presented his findings at the AAEP convention.

In a vitrectomy, the veterinarian removes the vitreous, which is the soft, jelly-like tissue that fills the space between the posterior part of the lens  and the surface of the  eye. Gilger said that while CVs might decrease the number and severity of ERU episodes--keeping the eye comfortable and eliminating the need for enucleation (eye removal)--there is a high cataract formation rate.

Cyclosporine implants are devices that release low levels of Cyclosporine A, an immunosuppressant drug. The implants are designed to prevent the recurrence of ocular inflammation. The implants can be effective for up to five or six years. According to Gilger, implant recipients have minimal complications, ERU episodes are significantly reduced, and many of the horses regain normal vision.

Cyclosporine implants are indicated for eyes with progressive ERU but minimal ocular changes, whereas CV is recommended for horses in a more advanced stage of ERU.

Split-Thickness Meshed Grafts

There are several advantages of meshed skin grafts over nonmeshed ones, said Peter Rakestraw, MA, VMD, Dipl. ACVS, of Auburn University's College of Veterinary Medicine. They allow covering of large wounds with smaller pieces of donor skin; allow antimicrobial medications to contact the wound; and have better drainage, better conformation to the wound, and better handling of motion. Another benefit of meshed grafts is a better final appearance than pinch or punch grafts, which often yield tufts of hair surrounded by hairless skin.

Aseptic technique is vital to the survival of the graft, both during the grafting procedure and when changing bandages following the procedure.

Rakestraw estimated that a significant portion (over 50%) of meshed grafts take roughly 70% of the time, compared to a success rate of 50-90% with pinch and punch grafts. The meshed grafts are more expensive than other grafts, but the followup wound care is the same. Proper training might allow this technique to be practiced on an outpatient basis or even at the farm, significantly reducing the cost, he concluded.

Laser Surgery for Cribbing

Daniel Burba, DVM, of Louisiana State University, reported on the use of laser surgery to solve cribbing in horses. The surgical involves removing a portion of muscles (the sternohyoideus and omohyoideus muscles) in the neck. In his study, Burba said, laser surgery alleviated cribbing in 14 of 14 cases. Using laser surgery resulted in less hematoma and seroma than would be expected with conventional surgery. He suggested that one reason for the high rate of success was because the surgery was performed on the muscles in a more rostral (forward) location.

"More rostral transection of the sternohyoideus and omohyoideus muscles might decrease the possibility of a fibrous union forming between transected muscle ends, which we believe is vital to increasing the success rate," he said. "Minimizing seroma or hematoma formation post-operatively might decrease fibrous tissue formation and also improve the success rate."

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