A mastoidectomy is a surgery that removes diseased cells from the air-filled spaces in the mastoid bone (which is located behind the ear). Mastoidectomy is often used to treat cholesteatoma (a noncancerous growth that forms behind the eardrum), or ear infections that have spread into the skull. It’s also used when placing cochlear implants.

A mastoidectomy helps enable proper drainage and ventilation of the mastoid bone. Additionally, it prevents potential complications that could extend into the inner ear, leading to hearing loss, dizziness, or even life-threatening infections.