Congenital anomalies of the ossicles without deformities of the external ear

Abstract

Anomaly of the ossicles is frequently seen in a patient with congenital anomalies of the head or face, such as congenital obstruction of the external ear canal, Treacher Collins syndrome or cephalopathy. Congenital anomaly of the ossicles however is not a rare occurrence even in a patient without anomalies of the head or face.Here, we would present our own experience with six cases of congenital anomalies of the ossicles and with one case of congenital deformity of the round window. The patients with anomalies of the ossicles had non-progressive hearing impairment of purely conductive type, except for one case which had been accompanied by otosclerotic changes and had a bone conduction loss.Case 1. 24-year-old male.An exploratory operation of the left ear had revealed that there were a bony fusion of the short process of incus with the horizontal semicircular canal and a dislocation of the long process of incus, resulting in separation of the incudostapedial joint. The bony bridge was removed and the separated joint was reconstructed by means of a polyethylene tube strut. The acoustic gain was 42db.Case 2. 41-year-old male.Congenital anomaly of the left middle ear was found to be a bony fusion of the short process of incus with the horizontal semicircular canal. The bony bridge was removed, resulting in a hearing improvement. But his hearing became wor se after several months, probably due to recurrence of ankylosis.Case 3. 21-year-old male (left ear)Case 4. 24-year-old male (left ear)Both cases had congenital separation of the incudostapedial joints, due to maldevelopment of the long process of incus. These separated joints were reconstructed by means of a polyethylene tube strut. Hearing improvement were considerable in both cases.Case 5. 31-year-old male.Congenital absence of the head and crus of the stapes was found in his left ear. The foot-plate was movable. A polyethylene tube collumela was introduced between the long process of incus and the foot-plate. Hearing gain was about 30db.Case 6. 38-year-old female.The patient had otosclerosis in both ears. Congeaital separation of the incudostapedial joint was seen in the left ear. Following a stapes mobilization operation, the ossicular chain was reconstructed by means of a polyethylene tube strut. Hearing gain was considerable.Case 7. 25-year-old female (right ear).The round window niche was remarkably narrow.