Factors affecting hearing results after stapes surgery.

Factors affecting auditory improvement after stapes surgery were investigated retrospectively on a study group of 106 otosclerotic ears (86 subjects). While the closure of the air-bone (A-B) gap after surgery was good at 2 kHz and 4 kHz, it was poor at 8 kHz and at frequencies lower than 1 kHz. Under 1 kHz, the lower the frequency, the worse the A-B gap after surgery. Stapedotomy and partial stapedectomy showed better post-operative hearing gain at 4 kHz than total stapedectomy. Total stapedectomy scored significantly better at 250 Hz and 500 Hz than stapedotomy. There was a close relationship between the pre-operative and post-operative A-B gap at frequencies under 1 kHz. The smaller the pre-operative A-B gap, the better the closure of the post-operative A-B gap at these frequencies. It was speculated that otosclerotic ears with a larger pre-operative airbone gap might have another lesion in the middle ear other than the oval window.