経外耳道性外傷による耳小骨骨折

FRACTURE OF THE MALLEUS HANDLE DUE TO PER-MEATAL INJURY

　外傷性の耳小骨離断の原因および，その受傷部位としてもつとも多いものは頭部外傷によるきぬた骨の偏位である。耳小骨の骨折は経外耳道的に異物が入り耳小骨に直接外力が加わつた場合にみられることもあるが，非常に稀である。

　ここに報告する症例はつち骨柄の骨折をおこしたもので，手術によりある程度の聴力改善を得ることができたものである。

　A 34 year-old woman suffered from tinnitus and loss of hearing following accidental introduction of a frame of an umbrella into the external ear canal.

　An audiogram taken thereafter demonstrated a combined hearing loss. The tympanogram was indicative of a separated ossicular chain. No stapedial reflex was detected on the affected ear.

　Fracture of the malleus handle was witnessed by exploratory tympanotomy. The fractured handle was lifted up and moved on to the long process of the incus.

　The hearing was improved postoperatively; stapedial reflex was demonstable. However, the tympanograms still showed a deep type A by American Electromedics' impedance audiometers and notches by Grason-Stradlers' otoadmittance meter.