キヌタ骨長脚が鼓膜より突出した耳小骨離断の1例

Ossicular Dislocation with Projection of the Incus from the Ear Drum caused by Direct Trauma:A Case Report

　はじめに

　外傷性耳小骨離断は日常臨床においてしばしば経験するが，多くは交通事故や，災害事故など他の外傷を伴って生じることが多い。耳清掃中に生じる中耳外傷は鼓膜穿孔，鼓膜裂傷が多く，時に直接損傷により耳小骨離断を生じ，めまい，難聴，耳鳴を起こすことがある。

　今回われわれは，耳清掃時の耳かき棒による鼓膜穿孔と，キヌタ骨長脚が鼓膜より突出した非常に稀な外傷性耳小骨離断の1例を経験したので報告する。

A 23-year-old man complained of a hearing loss and tinnitus occured just after injuring the left ear drum with an ear pick. Through a perforation the incus was projecting. Pure tone audiometry showed a mixed hearing loss of 55 dB. Vestibular function tests showed no nystagmus. High resolution CT showed dislocation of the incus preoperatively. Exploratory tympanotomy was performed, and in-cudostapedial joint was found dislocated, but the oval window was normal. Ossicular chain continuity was reconstructed by auricular cartilage. Postoper-atively hearing was improved.