慢性中耳炎における感音性難聴

INNER EAR DEAFNESS IN CHRONIC OTITIS MEDIA

　I．緒言

　近年慢性中耳炎に対する微細手術は著しい発達を遂げ，その間中耳内の病変がどのような種類のものであり，非可逆的変化と可逆的変化はどのようにして区別されるか，それらの病変を終息せしめるには如何にすればよいかなど，病理学的，生化学的，細菌学的など種々の角度から検索されている。また外科的処置との関連において治療方法や治癒成績も多く研究されている。しかし中耳内炎症が内耳へ如何に影響するかについての検索は現状ではまだ十分とはいえない。一方，鼓室成形術は著しく進歩している反面手術操作のため術後の聴力が予期に反して改善されないのみならず，かえつて感音系難聴が加わつてかなりの増悪を来たす場合があり，非常に稀であるがろうに陥る場合さえ経験することがある。今回慢性中耳炎耳の聴力を骨導域値の面から統計的に観察し，これら症例の後術骨導域値の変動を追うことにより慢性中耳炎と蝸牛機能との関係を調べることを試みた。

　For the treatment of the middle ear infections systemic administration of antibiotics and local application of various anti-inflammatory drugs are being employed. For the treatment of chronic otitis media, tympanoplasty,especially, is performed in attempts at improving the hearing by abating the inflammatory process and thereby repair the damaged intratympanic sound conducting mechanism. It is indeed possible to abate the inflammation of the middle ear through these therapeutic procedures.

　However, on the other hand, it is not at all rare that the infection itself or the surgical procedures may result in untoward effects or other disorders.

　In order to clarify these points 168 cases of chronic otitis media cases, who underwent tympanoplasty were examined for statistical observation by obtaining preoperative and postoperative data of hearing. The results were as follows: In cases of chronic otitis media the lowering or loss of bone conduction hearings were invariably found. The higher the sound frequency the more marked was the hearing loss; the severer the lesion in the round and oval windows the greater was the loss of bone conduction hearing.

　Tympanoplasty may at times cause a transcient loss of boneconduction hearing which would be particularly large in the higher-frequency range of sound.