Abstract
The clinical records of 361 patients (377 ears) with middle ear diseases operated at the University of Tsukuba Hospital from January 2002 to December 2011 were reviewed. The majority of patients (247 ears: 65.5%) were diagnosed as having chronic otitis media with cholesteatoma. The overall success rate of treatment to improve hearing was 63.2% in patients with a cholesteatoma. There was a tendency towards the success rate being higher in patients undergoing type I tympanoplasty.