あぶみ骨前庭陥没を伴う外傷性鼓膜穿孔

Traumatic Luxation of the Stapes into the Vestibule

I．はじめに

　外傷性鼓膜穿孔は日常診療においてしばしば経験するものであるが，同時に前庭へあぶみ骨陥没を伴う例は少ない。われわれは外傷性鼓膜穿孔に耳小骨連鎖離断およびあぶみ骨の前庭陥没を伴う症例を経験したのでここに報告する。

　A 12-year-old girl suffered from vertigo, tinnitus and loss of hearing following accidental introduction of a twig into the left external ear canal. The tympanic membrane showed a small perforation in the superior-posterior portion and through it the capitulum of the stapes was visible. An audiogram showed a severe combined hearing loss with a slight increase of a bone conduction threshold in the left ear. When she assumed a left-side-down position, rotatory and horizontal nystagmus was elicited. The dizziness gradually subsided and the perforation healed.

　She underwent exploratory tympanotomy because of a 50-60 dB conductive hearing loss. The needle otoscope was introduced into the tympanic cavity after reflection of the tympanomeatal flap under general anesthesia. The incudomallear and incudostapedial joints were separated and the intact stapes was depressed into the vestibule. The incus and stapes were removed and the oval window was sealed by temporal fascia and gelfoam. The incus was trimmed and placed between the fascia and the tympanic membrane.

　Postoperatively, the hearing was improved and vertigo disappeared, but tinnitus remained unchanged.