顎関節ヘルニアを伴った特発性外耳道骨欠損症の1例

A case of persistent foramen of Huschke with temporomandibular joint herniation

はじめに

　特発性外耳道骨欠損は，外耳道の成長過程で本来5歳頃までに閉鎖する鼓室骨鼓室孔（foramen tympanicum，Huschke孔）に，原因不明の融合不全が生じ，骨部外耳道最深部の前壁皮下に骨欠損が遺残した状態である。同孔（以下，H孔）の存在のみでは無症状であるが，他疾患が併存しH孔を経て耳症状を呈すると特発性外耳道骨欠損症と称される。

　今回，筆者らは顎関節ヘルニアによる症例を経験したので，文献的考察を加えて報告する。

　Foramen of Huschke（foramen tympanicum）is an anatomical variation of the tympanic portion of the temporal bone. In a world-wide literature search, there were over 50 cases reported related to this foramen. 13 cases among them were reported in Japan. Herein, our case of foramen Huschke with herniation of the right temporomandibular joint that result in aural fullness and rustling sound during mastication and its treatment are described. A 9×10 mm size foramen was identified at the deep surface near the petrotympanic fissure. The dehiscence was covered by titanium mesh. More than seven years follow-up after the operation, the patient spent without symptome.