This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
[{'content': 'All of the following steps are done in radical mastoidectomy except - \nSelect and explain. \nA. Lowering of facial ridge, B. Removal of middle ear mucosa and muscles, C. Removal of all ossicles except stapes footplate, D. Maintenance of patency of eustachian tube', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Steps in radical mastoidectomy\n\nThe posterior meatal wall is removed and the entire area of the middle ear, attic, antrum and mastoid is converted into a single cavity, by removing the bridge and lowering the facial ridge.\nAll remnants of tympanic membrane, ossicles (except the stapes footplate) and mucoperiosteal lining are removed.\nThe eustachian tube is obliterated by a piece of muscle or cartilage.\nThe diseased middle ear and mastoid are permanently exteriorised for inspection and cleaning.', 'role': 'assistant'}]