アブミ骨筋腱骨性固着症の2例

Two Cases of Fixation of the Stapedial Tendon

はじめに

　鼓膜所見に異常のない伝音性難聴を呈する疾患は，耳硬化症，耳小骨奇形など種々のものがある。その中で，アブミ骨筋腱固着による報告は少なく，われわれの調べた限りで，わが国では先天性4例^1,2），後天性ではわずかに1例^3）報告があったのみで，欧米でもはっきりとした症例報告は4例^4〜7）のみであった。今回われわれは耳小骨奇形を伴わないこの症例を先天性，後天性共に1例ずつ経験したので報告する。

Two cases of congenital fixation of the sta-pedial tendon uncomplicated by malformations of the auditory ossicles were recently experienced.

Case 1. A 40-year-old male had a left con-genital fixation of the stapes. On the contralateral side, a single crus malformation had been surgi-cally treated with subsequent improvement of auditory function. The similar malformation was suspected on the left side and surgery was per-formed. The normally appeared stapedial tendon was found but cutting of the stapedial tendon resulted in improvement of the auditory acuity from 55.5 to 20.5dB.

Case 2. A 59-year-old female complained of gradual deterioration of auditory acuity. Surgery was performed under the initial diagnosis of oto-sclerosis. The stapedial tendon was almost ossified, unlike the findings of otosclerosis. Severance of the stapedial tendon alone improved the acoustic function from 46.2 to 21.2dB. One of the mech-anisms of ectopic calcification appeared to be responsible.