Open AccessThe Third Mobile Window Effects in Otology/Neurotology
Author(s) -
Ichiro Ota,
Masaharu Sakagami,
Tadashi Kitahara
Publication year - 2021
Publication title -
the journal of international advanced otology/the journal of international advanced otology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.518
H-Index - 13
eISSN - 2148-3817
pISSN - 1308-7649
DOI - 10.5152/jiao.2021.8632
Subject(s) - otology , medicine , round window , oval window , neurotology , bone conduction , inner ear , middle ear , temporal bone , tympanoplasty , fistula , audiology , anatomy , stapes , surgery , otorhinolaryngology , head and neck surgery
It has been revealed that the pure-tone audiometry demonstrates large air-bone gaps at low pitches due to the presence of inner ear fistulae. When a third mobile window resulting from an inner ear fistula is present, in addition to the 2 normally present windows consisting of the oval window and the round window, a portion of the air-conducted waves escape from the scala vestibuli through the inner ear fistula. On the other hand, bone-conducted waves traveling to the scala vestibuli are reduced by an inner ear fistula; however, bone-conducted waves traveling to the scala tympani are not affected by an inner ear fistula. This results in a larger gap than usual in compliance between both perilymphatic spaces and leads to a decrease in the bone conduction threshold. This phenomenon, so-called the third mobile window effects, sometimes may lead otology/neuro-otology surgeons to misunderstand the reason why large air-bone gaps still exist after ossicular reconstruction in tympanoplasty. This review article gives good examples regarding the third mobile window effects in otology/neuro-otology diseases and surgeries.