Effect of Mastoidectomy and Posterior Tympanotomy on Postoperative Hearing

Lee, Kwang Sun; Yu, Hwa Kyung

Abstract

To evaluate the effect of mastoidectomy and posterior tympanotomy on postoperative hearing, 101 cases of type I tympanoplasty operated by one operator were retrospectively reviewed. The patients were divided into three groups; Group I(N=14) was the type I tympanoplasty without mastoidectomy ; Group II(N=44) was the type I tympanoplasty with simple mastoidectomy ; Group III(N=43) was the type I tympanoplasty and mastoidectomy with posterior tympanotomy. The type of operation was determined by preoperative physical finding, radiological findings, and decision was finally made during the operation. Preoperative mean air-bone gaps of pure tone average were significantly different among three groups(group I;13 dBHL; group II ; 22 dBHL, group III ; 31 dBHL). There was no significant difference of the postoperative air-bone gap gains at speech frequencies among three groups and the average gain was about 9 dBHL at 3 months, 11 dBHL at 6 months. respectively. However, the postoperative hearing was significantly changed according to the types of operation in the air and bone conduction, specially in the high tone area. At the 4 kHz, postoperative bone conduction did not changed significantly in the group I and II, however, postopearive bone conduction significantly worsened from 14 dBHL to 20-22 dBHL in the group III. In the same time, air conduction at 8 kHz was significantly aggravated from 52 dBHL to 65 dBHL postoperatively in the group III.