Neurosurgeons are commonly called upon to conduct heroic and sometimes unusual duties in order to save and enhance human life. Yet, it is not so common to donate time and efforts to save the life of a gorilla. But two neurosurgeons at Loyola University Medical Center (LUMC) in Chicago did just that on December 21, 1994.
Douglas Anderson, MD, with the assistance of Andrew Zelby, MD, performed surgery on a male western lowland gorilla. Although physicians have successfully treated head injuries in gorillas, this was the first recorded attempt by neurosurgeons to undertake microsurgery in a gorilla’s brain to remove a tumor similar to one that can develop in humans.
“This was a joint effort on the part of Loyola and Brookfield Zoo to save the life of a male western lowland gorilla, which is just now reaching the prime of its life has a critical role to play in maintaining its endangered species in American zoos,” said Dr. Thomas Meehan, Chief Veterinarian at Brookfield Zoo.
The 250-pound, nine-year-old gorilla, named Chicory, came to Brookfield Zoo in Brookfield, Ill., six years ago from Audubon Park and Zoological Gardens in New Orleans on a breeding loan. In February of 1994, Chicory began exhibiting occasional spells of balance-related problems, muscular weakness, shakiness, general malaise and lack of appetite. As the spells increased in frequency and duration, the zoo veterinarians consulted Loyola neurologist Madeleine Grigg-Damberger, MD, about the apparent seizures. By then, Chicory had an eight-month history of non-specific neurologic signs that became more diffuse and longer in duration with each episode.
Dr. Grigg-Damberger recommended taking an magnetic resonance imaging scan of the gorilla’s head at LUMC. The images revealed the presence of a large mass, about the size of a lemon, on the right side of the brain. After review by both Drs. Anderson and Meehan, they emphasized that the animal faced two options: dying as a result of the tumor or undergoing potentially lifesaving surgery. The second was the obvious option.
His prognosis was very poor unless the tumor was surgically removed. Similar tumors in humans generally respond well to surgery with complete return to normal function.
“We felt it appropriate to attempt the surgery, so we contacted Loyola for assistance. Chicory represents a breeding animal that is not very plentiful on this planet. This is an all-out effort to preserve a member of an endangered species,” Meehan said.
Donating their services in this endeavor, Drs. Anderson and Zelby undertook a thirteen-and-a half-hour surgery to remove the brain tumor in specially-equipped support facilities not used by human patients at Loyola University Medical Center. “All precautions were taken to minimize risks to the animal during surgery,” Dr. Anderson added. Recovering well after the tumor was removed, “Chicory was walking around, eating well, and responded to his keepers. He remained under 24-hour care and continued to receive medication to aid in his recovery,” said Dr. Meehan.
Monday, December 26, five days after surgery, Chicory began developing problems. Loyola neurosurgeons and zoo veterinarians performed a procedure on Chicory in Brookfield Zoo’s Animal Hospital to relieve inflammation and fluid buildup resulting from the brain surgery. “This condition is not an uncommon problem in humans who have had the same type of surgery,” said Dr. Zelby. Both neurosurgeons and other Loyola medical staff visited Chicory during this week.
On January 6, 1995, Chicory was moved from Brookfield Zoo’s Animal Hospital to the gorilla holding area in Tropic World. The gorilla remained under 24-hour watch for three days as he settled into his area, which physically separates him from the zoo’s other eight gorillas but allows him to see and communicate with them.
Chicory remained off public exhibit for several weeks until zoo veterinarians and keepers were confident he regained his strength and his skull was fully healed. “We wanted to make certain Chicory has the strength to maneuver in the gorillas’ public exhibit area which was deliberately built with many climbing challenges. We are very pleased at his progress since the surgery, and based on his activity and appetite, feel he is doing well enough to return to the gorilla holding area in Tropic World,” said Dr. Meehan. Since then, he has been recovering steadily. He went back on exhibit in February, 1995.