Type IV Tympanoplasty Results after Stapedectomy

Abstract

Of the patients on whom type IV tympanoplasty after stapedectomy has been performed since 1966 at the Otolaryngological Clinic, Ojiya Hospital, two cases are reported. Type IV tympanoplasty after stapedectomy was performed using the fascia temporalis and the application of a plug consisting of absorbable gelfoam dipped in a mixture of 0.5% Chloromycetin and 1% hydrocortisone acetate at the oval window following the removal of the stapes facilitated the formation of a new membrane at the oval window. Due to the enlargement of the small tympanic cavity, cochlear fluids are set freely in motion, so that the round window membrane become freely movable following release of the displaced perilymph, resulting in a marked improvement in hearing. The formation of a prominent peak at 2000 Hz following postoperative hearing acuity and the loading test at the oval window may indicate the minimum acoustic impedance of the inner ear. Due to a series of loading tests, sound energy will be considered to be propagated chiefly through the route of external ear canal—oval window—inner ear. It seems to the author that type IV tympanoplasty involving complete removal of the pathological stapes is worthy of notice in stapes surgery.