Canal wall-up mastoidectomy for cholesteatoma

When a cholesteatoma has extended beyond the accessible confines of the middle ear, it is necessary to remove cranial bone to reach the temporal bone spaces above and behind the middle ear.
(A) The mastoid cortex is removed with a drill.
(B) The mastoid cortex has been removed to expose a cholesteatoma of the middle ear, attic, and mastoid. The posterior ear canal wall is left intact to separate the middle ear and mastoid in a canal wall-up mastoidectomy.