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LAPAROSCOPY: Advances in surgical techniques
easier on horses
by Jennifer Lansdowne, Ludovic Bouré,
Simon Pearce Department of Clinical Studies Ontario Veterinary College
University of Guelph
Cryptorchidism is a developmental defect
in both animals and humans that is characterized by failure of one or
both testes to descend into the scrotum. Descent of the testes normally
occurs in the male fetus. The testes move from within the abdominal cavity
through a space called the inguinal canal, to a position outside the body
cavity within the scrotum. In male foals, this process is generally completed
by two weeks of age. Interruption in this process will result in one or
both testis being retained anywhere along its route. Thus the testes may
be located inside the abdomen, within the inguinal canal or under the
skin in the inguinal (groin) area.
Retained testicles are not fertile (they do not produce viable sperm),
but do produce male hormones (testosterone), causing the cryptorchid horse
to have the behavioral characteristics of a stallion. Many veterinarians
and breeders believe that chryptorchidism is heritable. This means that
a stallion that has one chryptorchid testis and one normal fertile testis
can pass on the trait to his offspring. Retained testes have a tendency
to become cancerous in horses, and testes that are retained in the inguinal
area may be associated with hind limb lameness in some horses. For these
reasons, castration of cryptorchid horses is recommended.
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Drs. Ludovic Boure and Simon Pearce perform a laparoscopic cryporchidectomy
on a horse under general anesthesia. The procedure may also be done
in a standing, sedated horse. This less invasive surgical techique
is being mastered at the OVC, and is also proving successful for
removing ovaries in problem mares. The research team continues to
investigate new applications for this procedure.
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A laparotomy is the typical procedure used to castrate cryptorchid stallions.
A laparotomy requires general anesthesia and is an invasive surgery, resulting
in a large incision in the body wall. In the last six years, laparoscopic
cryptorchidectomy has been successfully developed and performed in horses.
Laparoscopy has many advantages over laparotomy in the surgical correction
of cryptorchidism. Laparoscopy is a less invasive procedure, requiring three
or four 1-cm incisions. These small incisions decrease the time required
in surgery and in closing the surgical incisions, as well as decrease the
time required for the horse to be off exercise while the incision heals.
The retained testis can easily be identified using laparoscopy, thus there
is less chance of accidental trauma to the abdominal organs during the surgery.
Laparoscopy can also be very useful for the evaluation and the treatment
of male horses with no palpable testes but with a known history of displaying
stallion-like tendencies. Often, these horses are required to go through
an exploratory laparotomy under general anesthesia. This surgery is invasive
and requires exploration of both inguinal areas up to the abdominal cavity.
Laparoscopy in these horses permits a non-invasive exploration of the abdominal
cavity and the accurate distinction between a gelding and a cryptorchid.
During the surgery, if a retained testis is found, it can be easily removed.
The major disadvantages of laparoscopy are cost of equipment and training.
The equipment necessary to perform laparoscopic evaluation of the abdominal
cavity is likely too expensive for the average practitioner, but many veterinary
teaching institutions are equipped with the latest in laparoscopic technology.
There is a high level of expertise and training required to perform this
technique.
Laparoscopic cryptorchidectomy is a safe procedure, but the anesthetized
horse must be monitored by a veterinarian specialized in equine anesthesia.
Potential complications do exist, but these can be kept to a minimum through
the mastering of the laparoscopic technique by the veterinary surgeon and
through meticulous monitoring and observation of the horse. Laparoscopic
technology is currently available at the Ontario Veterinary College, and
as such is readily accessible to horse owners.
www.erc.on.ca
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