Learning Objectives:

The committee on Nomenclature of the Japan Otological Society (JOS) was appointed in 2004 to create a cholesteatoma staging system widely applicable in Japan and as simple as possible to use in a clinical practice. After the initial proposal of the principal staging system for attic cholesteatoma in 2008, we proposed a 2010 version of the staging system for two main types of acquired cholesteatoma; pars flaccida type and pars tensa type. Since then, this staging system has been widely used in Japan, allowing for more meaningful communication between outcome studies based on surgical methods used for a respective type and stage of cholesteatoma.

A nationwide survey was conducted by the Committee of JOS in order to promote the use of this system among JOS members and to capture the prevalence of cholesteatoma types and stages in Japan in 2015. The operative methods employed in each case were also included to reveal the current trends of cholesteatoma surgery in Japan. Medical information of the patients were anonymized and registered through the JOS website voluntarily between 1 January and 29 February 2016.

As of 2016/02/27, 1480 cases from 59 hospitals have been registered. 99.8% underwent general anesthesia as to local anesthesia 0.2%. Transcanal, retroauricular, and endaural approach was carried out in 8.0%, 88.5%, and 3.5% of the cases respectively. In terms of equipment, microscope alone was used in 74.0%, as to endoscope alone 6.7%. Combination of both microscope and endoscope was used in 19.3%. As to surgical procedure, canal wall down tympanoplasty without canal wall reconstruction, canal wall down tympanoplasty with canal wall reconstruction, canal wall up tympanoplasty, and tympanoplasty without mastoidectomy was pursued in 16.6%, 33.2%, 28.6% and 21.6% respectively. Based on the final registration data, we will propose and analyze the surgical procedure of each stage of cholesteatoma.