Nationwide survey of middle ear cholesteatoma surgery cases in Japan: Results from the Japan Otological society registry using the JOS staging and classification system.

Objective: This study was aimed to determine the characteristics of middle ear cholesteatoma and to investigate short-term outcomes regarding the rates of residual and recurrent cholesteatoma and the postoperative hearing results in Japan, via a nationwide survey using staging and classification criteria for middle ear cholesteatoma, as proposed by the Japan Otological Society (JOS).

Methods: The first-round survey was conducted in 2016. The target was patients with middle ear cholesteatoma who were surgically treated in Japan between January and December 2015. Medical information on the patients was anonymized. The questionnaire entries were age, sex, cholesteatoma classification and stage, preoperative hearing level, mastoid development, status of the stapes, and surgical method. There were a total of 1,787 registered patients from 74 facilities from all over Japan. The second survey was conducted in January 2018 and received 1,456 responses from 49 facilities in Japan. Of the 1,456 cases, 1,060 were conducted in the postoperative hearing survey and 1,084 in the residual recurrence survey.

Results: The most common cholesteatoma type was pars flaccida cholesteatoma (63.3%), followed by pars tensa cholesteatoma (13.0%), congenital cholesteatoma (12.9%), and cholesteatoma secondary to chronic tensa perforation (5.6%). Cholesteatoma of uncertain origin accounted for 5.0% (90 cases). Stage II was predominant in pars flaccida and pars tensa cholesteatoma, which frequently involves the mastoid, whereas about half of cases of cholesteatoma secondary to chronic tensa perforation and congenital cholesteatoma were classified as stage I. One hundred fifty-two of 1,084 cases (14.0%) had recurrent cholesteatoma, residual cholesteatoma, or both following first surgeries. The postoperative rates of hearing success rate was 63.3%.

Conclusion: We were able to clarify not only the current epidemiological status of middle ear cholesteatoma but also the current trends of cholesteatoma surgery in Japan. The development of a staging system by the JOS Committee serving an epidemiological database for international or time-dependent comparison. It is possible to use this staging system with reasonable reliability.