外傷性伝音難聴について—特に手術所見を中心として

Post-traumatic Conductive Hearing Loss

I．はじめに

　外傷性の伝音難聴は，鼓膜損傷，鼓室内あるいは外耳道の出血による場合が多く，保存的な治療により聴力改善をみる場合が多い。しかし，何らかの原因で鼓膜穿孔の閉鎖が遅延する場合や，耳小骨連鎖に異常がある場合は，手術的治療を行わざるを得ない。我々は外傷後に難聴を主訴として来院し，手術を行った症例19例につき，手術所見を中心に，若干の考察を加えて報告する。

　Nineteen cases of post-traumatic conductive hearing loss were studied, and 10 cases out of 19 cases showed a perforation of the tympanic membrane without any ossicular chain lesion. These cases were treated as out-patients for at least 3 months until myringoplasty was done. Several factors which contributed to the delayed healing of the tympanic membrane are discussed.

　Nine cases had ossicular lesion, and in 6 cases the incudostapedial joint was disarticulated and the displacement of the incus was observed. These cases showed immobile ossicular chain. Movement of the chain was recovered by the removal of the epitympanal bony wall. This suggests that ossicular chain fixation might be caused by the displaced fragments of the epitympanal bony wall.