Isolated Congenital Incus Anomaly

Abstract

Background and Objectives : A non-progressive and conductive hearing loss with normal eardrum, which has no history of trauma and infection is highly suggestive of a congenital ossicular malformation. Among ossicular anomalies, the most common anomalous ossicle is stapes. However, incus anomaly is sometimes encountered with or without stapes anomaly. The objectives of this study are to describe patterns of incus anomaly, encountered in patients who have a normal eardrum and to analyze their surgical results with special reference to the patterns of incus anomaly. Subjects and Method : We reviewed 26 patients (31 ears) with congenital incus anomaly, which were confirmed through exploratory tympanotomy at Ajou University Hospital from 1994 to 2005. We analyzed temporal bone CT, preoperative and postoperative audiometric findings, and surgical findings. Results : 10 anomalous patterns were detected out of 31 cases of congenital incus anomaly. Incus without its long process was the most common anomalous pattern. In 15 out of 26 cases (57.7%), incus anomaly was associated with stapes anomaly, which was usually unilateral. We could get hearing improvement in 26 out of 31 ears (89.1%). Conclusion : Various anomalous patterns of incus were noted in our series. Incus anomaly was often associated with stapes anomaly, which was usually unilateral. The surgical result of incus anomaly was excellent except the cases without stapes.