Monopodal stapesであった先天性伝音難聴の1症例

Monopodal Stapes:A Case Report

　はじめに

　先天性アブミ骨奇形には，その完全な欠損から，形態は正常であるが底板の固着があるものまで種々のものが知られている^1〜5）。

　その中でmonopodal stapesは，アブミ骨脚が1本の脚に融合したままの状態の奇形である。比較的稀な耳小骨奇形であるとされており，本邦では本症のみを独立して取り上げ検討した報告は少ない^6）。

The authors presented a case of “monopodal stapes”, which is characterized in the presence of one central crus and the absence of the normal stapes structure.

A 28-year-old female showed a bilateral conduc-tive hearing loss. A right middle ear exploration was performed and the following anomalies were observed:1) fixation of the long process of the incus to the tympanic wall, 2) monopodal stapes with crus fixed to the fallopian canal. The forma-tion of footplate was normal, and fixation of the footplate was not observed. The conduction chain was reconstructed by a sliced cartilage after mobili-zation of the stapes. Hearing improvement of 30 dB was obtained.