Minor ossicular anomalies in the middle ear: role of submillimeter multislice computed tomography.

OBJECTIVE: The objective was to elucidate clinical effectiveness of submillimeter multislice 2- and 3-dimensional computed tomography (CT) for diagnosis of congenital middle ear anomaly. MATERIALS AND METHODS: Preoperative CT and operative findings were retrospectively analyzed in 36 ears of 33 patients. The distance between the malleal handle (MH) and the incus long process (ILP) was measured in 28 normal ears. RESULTS: Mean ± SD MH-ILP distance in normal ears was 1.8 ± 0.3 mm. In patients with middle ear anomaly, overall specificity, accuracy, and positive and negative predictive values were 99.7%, 98.7%, 91.7%, and 99.1%, respectively. Overall sensitivity was 82.1%, with relatively low sensitivities for detecting fused incudomalleolar joint, lenticular process defect, stapedial footplate defect, and oval window atresia and high sensitivities (80%-100%) for stapedial crural anomaly and certain fibrous connections. CONCLUSIONS: Submillimeter CT improved detectability of anomalies of the stapedial superstructure; however, it is still difficult to identify abnormalities of the footplate.