ツチ・キヌタ骨の癒合・変形・固着とアブミ骨上部構造の変形を合併した耳小骨奇形の1例 Congenital adhesion and fixation of the malleus and incus with deformity of the stapes : a case report
We report a case of congenital adhesion and fixation of the malleus and incus associated with deformity of the stapes superstructure in a 39-year-old man. He had a right auricular malformation (so-called cupped ear) and an ectopic handle of the right malleus without deformity of the external auditory meatus. He complained of hearing impairment on the right side. Pure tone audiometry showed conductive hearing loss of 63.3dB in the right ear. Computed tomography suggested deformity and fixation of the head of the malleus and body of the incus in the right tympanic cavity. Exploration of the right middle ear was performed and the following anomalies were observed: 1) osseous adhesion between the head of the malleus and the body of the incus with formation of the coalescence bone, 2) osseous fixation of the malleus/incus coalescence bone to the lateral wall of the tympanic cavity, and 3) severe deformity of the long process of the incus and the superstructure of the stapes. Fixation of the stapes was not observed. Removal of the bony tissue causing fixation of the malleus/incus coalescence bone was performed, and mobilization of all the ossicles was achieved while keeping the ossicular chain intact. Hearing improvement of 43dB was obtained.<BR>It was speculated that the anomalies were due to abnormal development of the first and second branchial arches at 6 to 7 weeks of the embryonic life.<BR>For classification of auditory ossicle malformations without associated abnormalities of the external auditory meatus, we should not only evaluate discontinuity or fixation of the ossicles but also the extent of deformity.
- Otology Japan
Otology Japan 16(3), 189-194, 2006-07-25
THE JAPAN OTOLOGICAL SOCIETY