SAN DIEGO (FOX 5/KUSI) — A lowland gorilla at the San Diego Zoo Safari Park underwent the first-of-its-kind mastoidectomy to treat an infection that had spread into parts of his skull.
The San Diego Zoo Wildlife Alliance said Monday in a news release that wildlife care specialists noticed in March that 12-year-old Mizani was reluctant to open his mouth, had a decreased appetite and was showing signs of having head pain.
Veterinarians performed a CT scan on Mizani, which showed that he had sinusitis and mastoiditis, which is an infection of the large bone behind the ear.
Based on Mizani’s condition, the Wildlife Alliance said that experts believe the infection developed before he arrived at the Safari Park in November 2024.
A multidisciplinary team of animal care experts at the San Diego Zoo Safari Park and surgeons from UC San Diego helped perform Mizani’s surgery.
The Wildlife Alliance said UC San Diego otolaryngologist-head and neck surgeon Jeffrey Harris and resident fellow Kris Suresh played critical roles in what is believed to be the first surgery of its kind performed on a gorilla in the world.
While gorilla and human anatomy can be similar, the surgical team had to adapt techniques from human medicine since no records existed of such a procedure being performed on a gorilla, according to the Wildlife Alliance.
“Our surgical team regularly performs complex mastoid and skull base procedures but applying that expertise to a critically ill gorilla required meticulous planning,” said Dr. Harris. “After carefully analyzing CT scans, we adapted our approach to account for the significant anatomical differences and proceeded with delicate microsurgery.”
An incision was made along the left side of Mizani’s head, where portions of the infected mastoid bone and tissue were carefully removed. The procedure was performed at the Harter Veterinary Medical Center and lasted approximately five hours.
More than 20 veterinarians, physicians, veterinary technicians, wildlife care specialists and staff from both the university and zoo helped.
“This case was particularly unique because this disease is rarely seen in gorillas, making it a valuable learning opportunity for everyone involved,” said Ryan Sadler, senior veterinarian at the San Diego Zoo Safari Park, in the news release. “Even after working with gorillas throughout my career, I’m still learning something new every day. Procedures like this highlight how medicine can be remarkably similar across species, while also requiring very different approaches depending on the animal.”
Mizani had a recheck exam in June. Zoo officials said he has shown significant improvement with no signs of complications.
He is scheduled for another recheck in a year, but in the meantime, he has returned to his normal diet, activity level and daily routine.
Mizani after his surgery (San Diego Zoo Wildlife Alliance).
Medical staff performing Mizani’s mastoidectomy (San Diego Zoo Wildlife Alliance).
Mizani post-op (San Diego Zoo Wildlife Alliance).
The portion of Mizani’s bone that was infected (San Diego Zoo Wildlife Alliance).
Scans of Mizani’s skull (San Diego Zoo Wildlife Alliance).
Mizani post surgery (San Diego Zoo Wildlife Alliance).
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