## Why option 1 is right The pattern marked **A** represents closure of the air-bone gap (air-conduction thresholds converging to meet bone-conduction thresholds) with resolution of the Carhart notch. This is the hallmark of successful stapedectomy/stapedotomy. The piston prosthesis, when properly positioned through the fenestra in the fixed stapes footplate and crimped onto the incus long process, restores mechanical coupling of the ossicular chain and allows sound vibration to transmit to the inner ear. The closure of the air-bone gap to ≤10 dB across speech frequencies (500–2000 Hz) and the "filling in" of the pre-operative Carhart notch at 2 kHz confirm that the ossicular fixation has been relieved and the prosthesis is functioning. Success rates of 90–95% are achieved in experienced hands with this audiometric pattern. ## Why each distractor is wrong - **Option 2 (Persistent conductive gap)**: Prosthesis displacement would result in a **persistent or recurrent air-bone gap** (>10 dB), not closure. The diagram shows closure, not persistence of the gap. - **Option 3 (Sensorineural loss from perilymph fistula)**: Perilymph fistula presents as **new high-frequency sensorineural hearing loss >10 dB**, not closure of an air-bone gap. The pattern **A** shows air-conduction rising to meet bone-conduction, which is conductive improvement, not sensorineural deterioration. - **Option 4 (Recurrent otosclerosis)**: Recurrent otosclerosis with regrowth of otospongiotic bone would present as **re-widening of the air-bone gap** over months to years, not immediate post-operative closure. **High-Yield:** Post-stapedectomy success = air-bone gap closure ≤10 dB + Carhart notch resolution at 2 kHz; any persistent gap or new SNHL mandates workup for prosthesis malposition or perilymph fistula. [cite: Dhingra Diseases of Ear Nose & Throat 7e Ch 15; Cummings Otolaryngology 7e Ch 144]
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