U of I Equine Surgeon Uses Balloons to Improve
Difficult Surgery
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Pet Column for the week of April 26, 1999
Office of Public Engagement
2001 S. Lincoln Ave.
Urbana, Illinois 61802
Phone: 217/333-2907
By Sarah Probst
Information Specialist
University of Illinois
College of Veterinary Medicine
Some fungal diseases, such as athlete's foot, cause superficial tissue damage and
inflammation in specific parts of the body. However, when a horse gets a fungal infection in
its guttural pouch, the tissue damage can go deeper and even erode through arteries and
nerves. Arterial erosion produces a large hole in the wall of the artery, and severe bleeding
from this is the most common complication of fungal infection in the guttural pouch.
Guttural pouches are found in horses and not in other domestic animals or human beings.
They are large extensions of the Eustachian tube, a canal that connects the throat cavity and
the inner ear. "Mycotic" is another word for "fungal," and veterinarians refer to a fungal
infection of the guttural pouch as "guttural pouch mycosis."
Many important arteries and nerves pass through the guttural pouch. Of these, the internal
carotid artery-the main supplier of blood to the brain-is most likely to be eroded by guttural
pouch mycosis. Usually only one of the two internal carotid arteries is affected, which is
fortunate because the horse needs only one to adequately supply blood to the brain.
"The resulting hemorrhage is typically recurrent and severe, and can eventually cause death
if not stopped," explains Dr. David Freeman, an equine surgeon at the University of Illinois
College of Veterinary Medicine Teaching Hospital in Urbana. Owners will observe this as
profuse bleeding from the nose. Unlike most bleeding from the nose in horses, it is not
brought on by exercise. When a horse experiences such bleeding, without recent severe
exercise, guttural pouch mycosis should be the top suspect. Other less common clinical
signs of guttural pouch mycosis include difficulty in swallowing, drooping eyelid, nasal
discharge, abnormal respiratory noise, abnormal head posture, and facial nerve paralysis.
The surgical technique devised by Dr. Freeman to treat bleeding from guttural pouch
mycosis has been widely acknowledged as the ideal method of treatment. Previous surgical
methods ligated (tied off with suture) the affected artery. Unfortunately, the internal carotid
artery does not end at the brain; instead, it joins up with several other arteries. Such
connections allow what is called collateral blood flow, a system that allows blood to flow
freely through that part of an artery beyond a ligature. As a result, blood can flow in the
opposite direction through the artery, and the horse can still bleed to death through the hole
in the arterial wall.
Two ligatures, one placed on each side of the hole in the artery, can eliminate all flow to the
site of damage and completely prevent bleeding. Unfortunately, the second ligature has to
be placed on the roof of the guttural pouch, an almost impossible procedure because the
artery is not readily accessible at this site, it is obscured by the infection, and it is so close to
vital nerves that nerve damage is almost certain.
Dr. Freeman's balloon-catheter technique has eliminated the problems associated with
double ligation and yet can safely eliminate bleeding. A catheter is a hollow, flexible tube
that can be put into a blood vessel or body cavity. In the case of the balloon-catheter, a
small balloon at the end can be inflated by injecting liquid into the catheter. When placed in
the damaged internal carotid artery, the balloon is inflated at a position that prevents blood
flowing backward from the brain, and does this without the risks and difficulties of a ligature
in the same place. The artery is also ligated where the catheter is inserted, thus preventing
blood flow from the heart.
New developments in surgery constantly change and improve the lives of animals and
human beings. Surgeons like Dr. Freeman continue to make such life-saving developments.
For more information about equine health, contact your local veterinarian.