The respective steering group of EAONO and JOS decided to work together to produce a single consensus document on the "Definitions, Classification, and Staging of Middle Ear Cholesteatoma" to globalize the system.
Six European otologists of the original EAONO steering group (Matthew Yung, Ewa Olszewska, Nuri Ozgirgin, Holger Sudhoff, Jef Mulder, and Armagan Incesulu) and four Japanese otologists of the original JOS steering group (Tetsuya Tono, Masafumi Sakagami, Yutaka Yamamoto, and Hiromi Kojima) participated in the joint EAONO/JOS steering group to work on the consensus project.
Except for some minor changes in the narratives, the original EAONO statements on definitions of cholesteatoma were adopted.
However, it may be located at the posterosuperior quadrant or other locations" is an amendment to the original EAONO statement to reflect the fact that many congenital cholesteatomas in Japan were found at the posterosuperior quadrant.
The term "chronic otitis media with or without cholesteatoma" in the original 2015 EAONO document was dropped from the joint consensus as the term is not universally accepted.
The classification proposed originally by EAONO and JOS independently were compared, modified, and merged: