New techniques make amputation more viable for some patients - DVM
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New techniques make amputation more viable for some patients


DVM360 MAGAZINE


Redden has pioneered the use of grafts of frog tissue that are harvested from the amputated limb, if possible. If the injury has damaged this tissue, then very small grafts are taken from the non-affected foot on the same side.

Redden describes the harvesting of this tissue as making a small slit over the frog and taking a strip of sensitive and non-sensitive tissue. This strip is placed in the stump ending or in a granulation bed if done after the stump has been created.

"It grows like crazy," says Redden, "and creates a wonderful, tough, resilient material for the bottom of the stump. It has to be trimmed every month or so, just like regular frog, or the prosthetic will not fit."

Fiberglass cast A fiberglass cast is constructed next and this cast incorporates both the transfixation pins and the temporary prosthesis.

Horses are recovered using a sling assembly. The use of the sling is crucial to success of this procedure as well since it further reduces post-op trauma. Horses are immediately weight-bearing through the transfixation cast and temporary prosthesis, and this eliminates the "break-down" problems seen on the contralateral limb.

The horse is then monitored closely and the cast changed every 30 days or so. At 10 to 12 weeks, the transfixation pins are removed.

Permanent prosthesis Once the stump has fully healed, a permanent prosthesis is constructed.

Complete healing usually takes 90 to 180 days. The permanent prosthesis is made of carbon graphite, fiberglass and polyethylene.

A prosthetic sock is applied beneath the device, and it is initially changed daily and monitored for pressure sores. It can eventually be changed weekly and the horse can usually be provided with unrestricted exercise five to six months post-surgery.

Success factors Drs. Vlahos, Grant and Redden all agree that patient selection is very important in eventual success.

The acutely injured horse is considered the ideal candidate. "Equine amputation and prosthetic repair is clouded by lack of information and communication," according to Grant.

He feels that too few owners and trainers really understand what is available through this procedure and how well these horses actually do. The perception is that even if the amputation works, these poor horses are merely cripples barely able to get around. "Nothing could be further from the truth," says Redden as he relates the antics of a mare that he has who has been an amputee for the last 11 years.

"She lives outside all year long, and bucks, and runs and plays just like a normal horse," says Redden.

This mare has been a successful broodmare and there have been successful breeding stallions that showed little problem with their handicaps. If amputation could be seen as something other than a last resort, then horses may be presented before they have developed problems of infection or breakdown in the opposite leg. These secondary problems make horses less likely to benefit from amputation, and this has only served to make owners question the efficacy of the procedure.

"Give me a healthy mare that breaks down acutely on the track and turning her around with an amputation and prosthetic repair would be relatively easy," says Redden. "She'd be the perfect candidate," he adds.

Owner commitment Owner commitment is important as well. This is a long-term project and it is unfair to the horse to put it through this procedure if the owners are not willing to see it through.

Grant laments the fact that more funding for amputation research is not available.

He cites the use of articulated prosthesis with electro-muscular implants as an exciting area worthy of more study. He hopes that interested and committed owners may eventually fund some of this needed research that will help further improve the chances for a horse with a catastrophic injury.

Horse's role The personality of the horse also has a lot to do with the eventual success of an amputation. Some horses learn quickly how to use their temporary prosthesis. They tolerate the sling, learn how to get up and lie down easily and tolerate the eventual prosthetic. Other horses struggle and make healing and rehabilitation harder.

Some of these horses do not make the adjustment and, though their stumps are healed, they refracture limbs or succumb to other trauma.

It is difficult to determine which horses will tolerate the procedure and which will have trouble. Helping train these horses to more easily accept convalescence and rehabilitation is another area of study that needs to be done, according to Grant.

Considerations The use of transfixation pins, a recovery cast and a sling greatly improved post-surgical success. The temporary prosthesis and frog grafting to produce a stable, healthy stump clearly added to the improvement of equine amputation to the point where it should now be considered as a potential treatment option in some cases. At a cost of $12,000 to $20,000, it is not a decision to be made lightly, but the chance to provide a good quality life to a breeding animal or valued companion should also be considered.

Most insurance companies will accept amputation as a legitimate procedure.

It is difficult to think of removing a horse's leg and even harder to recommend it to clients as an option, but with the new developments in amputation and prosthetic repair and with the dedication of veterinarians like Grant, Redden and Vlahos, we may find that three good legs are all that are needed.


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