This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Operative Surgery, Subject name: ENT
[{'content': 'Fenestration operation is which type of tympanoplasty- \nSelect and explain. \nA. Type-2, B. Type-3, C. Type-4, D. Type-5', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ans. is 'd' i.e., Type-5 Types of tympanoplastyo Wullstein classified tympanoplasty into five typesTypel: Defect is perforation of tympanic membrane which is repaired with a graft. It is also called myringoplasty.Type II: Defect is perforation of tympanic membrane with erosion of malleus. Graft is placed on the incus or remnant of malleus.Type III: Malleus and incus are absent. Graft is placed directly on the stapes head. It is also called myringostapediopexy or columella tympanoplasty.Type IV: Only the footplate of stapes is present. It is exposed to the external ear, and graft is placed between the oval and round windows. A narrow middle ear (cavum minor) is thus created, to have an air pocket around the round window. A mucosa-lined space extends from the eustachian tube to the round window. Sound waves in this case act directly on the footplate while the round window has been shielded.Type V: Stapes footplate is fixed but round window is functioning. In such cases, another window is created on horizontal semicircular canal and covered with a graft. Also called fenestration operation.", 'role': 'assistant'}]