突発難聴における正円窓膜破裂説について

THE ROUND WINDOW MEMBRANE RUPTURE

　I．緒言

　突発難聴の原因の一つに正円窓膜破裂説がある。この膜破裂をおこす誘因としては，肉体労働や頭部外傷，急激な外圧の変動などが挙げられているが，まつたく誘因なく膜破裂を認める症例もある。一方，人工的に正円窓膜を破つてみても聴力低下はほとんど認められないという。このように正円窓膜破裂が真に突発難聴の原因として存在するものかどうかまだ結論をみていない。われわれは，今回，諸種の治療に反応せず，鼓室試開を行ない正円窓膜破裂を認めた突発難聴症例と，突発難聴ではないが，外傷性の卵・正円窓破裂，外リンパ瘻症例を経験したので，この2症例をもとにして、突発難聴の正円窓膜破裂説について若干の考察を行ない報告する。

　Many etiologies about sudden deafness have been discussed recently. The round window membrane rupture is thought to be one of them. Two clinical cases were presented. The first case is a 53-year-old male who complained of sudden hearing loss and was surgically proved the round window membranerupture. The second one is a 21-year-old female who complained of hearing loss with vertigo after the mechanical injury of the left middle ear and was surgically proved perilymph fistula through labyrinthine window membrane rupture.

　According to these cases, a simple round windowmembrane rupture itself does not seem to cause a severe hearing loss in sudden deafness. Some damages in labyrinthine membrane other than the round window membrane rupture should exist so that suuden profound hearing loss might be caused.