Mastoidectomy involves the removal of bone and air cells contained within the mastoid portion of the temporal bone. Common indications for this procedure include acute mastoiditis, chronic mastoiditis, cholesteatoma, and the presence of tympanic retraction pockets. Mastoidectomy may also be performed as part of other otologic procedures (e.g. cochlear implantation, lateral skull base tumors, labyrinthectomy, etc.) in order to gain access to the middle ear cavity, petrous apex, and cerebellopontine angle. The procedure involves dissecting within the confines of the mastoid cavity, which include the tegmen superiorly, the sigmoid sinus posteriorly, the bony ear canal anteriorly, and the labyrinth medially. Mastoidectomy is traditionally classified as: simple (cortical/Schwartze), radical, and modified radical/Bondy’s mastoidectomy. The procedure can also be classified based on the preservation of the posterior canal wall: canal wall up (CWU) or canal wall down (CWD).