First-Reported Mastoidectomy Performed On Gorilla At San Diego Zoo Safari Park

SAN DIEGO, CA — A western lowland gorilla at San Diego Zoo Safari Park has recovered after undergoing what officials believe is the world's first reported mastoidectomy performed on a gorilla.

Mizani, a 12-year-old male, underwent the five-hour procedure in March after wildlife care specialists noticed he was reluctant to open his mouth, had a decreased appetite and showed signs of head pain, according to San Diego Zoo Safari Park.

Subscribe

A CT scan at the park's Harter Veterinary Medical Center found Mizani had sinusitis and mastoiditis, an infection of the mastoid bone located behind the ear that had spread into portions of his skull. Veterinarians believe the condition likely developed before Mizani arrived at the Safari Park in November 2024.

The surgery was performed by a team of wildlife health experts from the Safari Park and surgeons from UC San Diego Health, including Dr. Jeffrey Harris, an otolaryngologist-head and neck surgeon, and Dr. Kris Suresh, a resident fellow at UC San Diego Health.

Because no previous cases of the procedure being performed on a gorilla were found in scientific records, surgeons adapted techniques used in human medicine while accounting for anatomical differences between humans and gorillas.

The procedure involved an incision on the left side of Mizani's head to access and drain the infection, remove affected mastoid bone and tissue, and close the surgical site.

More than 20 veterinarians, physicians, veterinary technicians, wildlife care specialists and support staff took part in the surgery.

"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 Safari Park.

Mizani has continued to recover and returned to his troop after follow-up exams showed significant improvement with no complications. He has resumed his normal diet and daily activities and will continue to be monitored.

The procedure was performed as the Harter Veterinary Medical Center marks its 25th anniversary. The facility, which opened in 2001, has treated more than 50,000 animals representing hundreds of species, according to the Safari Park.