by Zoo Veterinarian Dr. Louise Beyea
Lake Superior Zoo Lead Keeper Emily Perala knows her lemurs. She’s the keeper who is
primarily responsible for the troop of charismatic, striped-tailed busy bodies in the Primate Care
Center.
When Emily informed me about a bump on the nose of Lillian, a 5-year-old female lemur, she
reminded me that Lillian’s father Reagan had a similar bump on his nose several years ago. We
biopsied the mass on Reagan’s nose and the swelling turned out to be a simple inflammatory
reaction (probably the lemur version of a pimple).
Emily’s plate is always full, and we had other animals on the schedule for veterinary care, so we
decided to wait and watch the bump on Lillian’s nose to see if it would follow the behavior of a
simple pimple and go away on its own. But like in every teenager’s nightmare before prom, the
prominent pimple persisted. Lillian’s lump had to be addressed.
Emily and Primate Keeper Bethany Wright first corralled Lillian in the lemur holding area, a room
with two “bedrooms” behind the lemur’s indoor exhibit. With Lillian in this smaller area, she
could be caught in a net, then transferred to a pet carrier for her trip up the hill to the zoo’s
veterinary hospital.
Next, Emily opened the pet carrier door and, wearing heavy leather welder’s gloves to protect
against bites, she grasped the lemur and held it still while I gave Lillian an injection of a sedative
into her rump muscle. In about 10 minutes, Lillian was woozy and we were able to get a better
look at her lumpy nose.
The mass was on the top left side of her nose, about half way between her eye and her nostril.
It was not movable and was very hard, like bone. This clearly wasn’t your average pimple. We
needed more information, and Lillian needed to be a bit more sleepy for us to do additional
tests.
Veterinary Technician Amy Gallagher had already prepared the zoo’s gas anesthesia machine
and gathered the equipment necessary to monitor Lillian if she needed to be put under
anesthesia. First, Amy held a conical mask over Lillian’s face that covered the animal’s mouth
and nose and allowed delivery of anesthetic gas and oxygen to the lemur. When Lillian was
suitably subdued, I opened her mouth to allow Amy to pass a breathing tube through the lemur’s
mouth and voice box and into the windpipe. The breathing tube was tied in place to Lillian’s
lower jaw and connected to the tubing of the anesthesia machine. Lillian was now fully
anesthetized.
We could now see that Lillian’s canine tooth, or fang, on the upper left side of her mouth was
broken off, leaving less than half of the tooth’s original length and exposing the inner pulp cavity
of the big tooth. One of Lillian’s troop mates was probably responsible for the broken tooth. We suspected that Lillian and one of her aunts got into a spat, which can get rather violent when
lemurs work out their grudges.
Canine teeth have loooooong roots. We traced the path of the tooth’s root with our fingers and
came close to the location of the lump on Lillian’s nose. It made sense that the broken tooth had
become infected through bacterial entry into the open pulp cavity.
An abscess develops when white blood cells congregate to kill bacteria. Millions and millions of
white blood cells result in pus, and that pus has to go somewhere. In the case of an infected
upper canine tooth, the pus travels the path of least resistance up and out the top of the tooth
root and into the surrounding tissue which is really close to the top of the nose.
Amy placed a small dental X-ray film into Lillian’s mouth and took an X-ray of the affected tooth
and its root. We could see a black area on the X-ray that abutted the root of the tooth. The
“black hole” indicated loss of bone, and was classic for the appearance of an abscess. Our
hunch was correct. Pimples are similar to small abscesses, and Lillian’s “pimple” was a tooth
root abscess.
Treatment options for abscessed lemur teeth are limited to root canal therapy or extraction.
Lillian’s tooth was broken off so short that it didn’t make sense to try to save the tooth, so
extraction became the treatment of choice.
Removal of a canine tooth in an animal is a daunting task. The canine teeth are some of the
biggest teeth in the mouth, and the long, curved roots are larger than the visible portion of the
tooth. I had never removed a canine tooth on a lemur, but planned to follow the same concepts
used when removing a canine tooth from a dog or cat.
In one respect, I expected the lemur’s tooth extraction to be a bit easier than in a dog because
the root of the tooth wasn’t quite as long as the root in a dog. When extracting a dog’s upper
canine tooth, a surgical flap in the gum tissue has to be created, extending the working area to
three teeth behind the canine tooth. Since Lillian’s tooth root was a little straighter, my working
area needed to extend back by only two teeth.
But I knew the lemur’s tooth was not as “beefy” as a dog’s tooth and would require a more
delicate hand. A dog’s tooth is roughly conical in shape. Lillian’s tooth was shaped more like at
the blade of a boat’s rudder: narrow and flat. That meant the tooth would be more fragile than a
dog’s tooth, and easier to fracture when it was removed.
While Amy expertly delivered the anesthesia and monitored Lillian’s vital signs, I used a scalpel
bade to cut Lillian’s gum and then very gently used a special dissection tool to lift the gum tissue
away from the bone of the upper jaw. This exposed the path of the tooth’s root. Next came
power tools: a high speed dental drill to remove the bone overlying the side of the tooth. This
process of bone removal made room for the use of an elevator, a hand tool that is used like a
precision pry bar. The elevator is twisted gently but firmly, then held in place for at least a count
of 10 to stretch the membrane that holds the tooth in the socket.
Thankfully, Lillian’s infected tooth elevated easily and came out in one, unbroken piece. The
socket that held the blade-like tooth was shallow and did not require filling with grafting material.
The socket was then flushed and the gum flap sewn back in place.
Lillian was given an injection of a long-acting antibiotic and got to go “home” with pain
medication. When she was fully awake, she was released into the “back bedroom” to await
being reunited with her troop. Emily reported that within two days, the lump on Lillian’s nose was
noticeably smaller, and within two weeks, there was no outward evidence of Lillian’s abscess.
If you have comments about this blog, or have questions you’d like me to address in future
blogs, please send me a message via email at lbeyea@lszoo.org. Let’s keep it wild until next
month!