Canal wall down mastoidectomy is done in cases of attic cholesteatoma. In this procedure mastoid cavity is left open into the external auditory canal. Since the patient in the question is suffering from attic cholesteatoma and secondary complications canal wall down mastoidectomy would be the treatment of choice. Other indications of this procedure includes extensive chronic otits media, formation of a new attic retraction pocket with disease following a previously performed canal wall up procedure, lateral semicircular canal fistula in the only hearing ear.