Spotlight on Vet Medicine
October 7, 2004
Mending a Monkey
National Zoo veterinarians use a special “pin” to repair the fractured arm of a Goeldi’s monkey.
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| Goeldi's monkey in Amazonia. |
Goeldi's monkeys (Callimico goeldi) are tiny New World monkeys, weighing just 17 to 18 ounces, with glossy black, long, silky fur over their entire body.
They are active during the day, when they forage for the invertebrates and fruits that make up the bulk of their diet. They are both arboreal and terrestrial, spending most of their time in trees but fairly close to the ground. They travel by leaping between undergrowth tree trunks.
The Goeldi’s monkey has a very small distribution in South America, in scrubby upland habitat at the base of the Andes mountains, where they are very rare. It is listed as endangered under the U.S. Endangered Species Act, and "near threatened" on the World Conservation Union (IUCN) Red List. It is also on CITES Appendix I, which means that international trade in the species is illegal except under exceptional circumstances.
Goeldi’s monkeys have long been resident at the National Zoo’s Amazonia exhibit. Recently, keepers at Amazonia called in the Zoo’s veterinarians, after noticing that Ivan, a 13-year-old Goeldi's monkey, had injured his arm. However, because Ivan was hiding high in the canopy of the trees in Amazonia, it was difficult for them to do a close examination. So keepers caught Ivan and took him to the Zoo’s veterinary hospital for a detailed physical exam and radiographs (x-rays).
Diagnosis
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| The fracture in the humerus is clearly revealed in this radiograph. |
The veterinarians anesthetized Ivan for the exam. When they felt his right arm, they detected a closed fracture. (A closed fracture is one in which they broken bone does not break the skin.) Radiographs confirmed the diagnosis: Ivan had fractured his humerus, which is the bone between the shoulder and elbow. The broken bones were severely out of line.
Treatment
Veterinarians performed surgery to insert an intramedullary (IM) pin into the bone marrow canal in the center of fractured humerus. Veterinarians use IM pin to align and stabilize fractures of long bones, such as the humerus. A cast, often used to set broken bones, helps support the bone while it heals. However, an IM pin actually shares the load with the bone, enabling the animal to use the affected limb more quickly.
Radiographs taken after the procedure confirmed that the pin was properly positioned and that the fracture was well aligned. Ivan was also given drugs reduce inflamation to prevent infection. Then he was returned to an off-exhibit area at Amazonia so he could be cared for by familiar keepers during his recuperation.
For the first few days after surgery, Ivan’s arm showed mild swelling and bruising. This is considered normal. At ten days, Ivan began to move his right arm and use his fingers to take food as well as to grab sticks.
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| This radiograph shows how the fracture has healed. |
The vets removed Ivan's stitches after three weeks and at that time found that the humerus was stable and there was no displacement on the fracture site. Radiographs revealed callus formation and good bone healing. The intramedullary pin stayed in place for eight weeks, which allowed the bone to heal perfectly, then was removed.
Prognosis
Ivan’s prognosis is very good. You can see for yourself how well he responded to treatment by visiting him at the National Zoo’s Amazonia exhibit.
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