The surgical removal of mastoid air cells during which the surgery may extend into the middle ear.

Mastoid air cells are open, air-containing spaces in the skull, behind the ear.

The surgery used to be a common way to treat an infection in the mastoid air cells, which usually came from an ear infection that spread to the nearby bone in the skull.

Mastoidectomy is now seldom needed because the infections are commonly treated with antibiotics; however, this surgery may be used to treat other problems; such as, cholesteatoma, complications of the otitis media, or used as a surgical approach for cochlear implant insertion.