Lateral Semicircular Canal Dysplasia in Middle Ear Cholesteatoma Patients / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Lateral semicircular canal (LSC) dysplasia is the most common congenital anomaly in the inner ear. The LSC dysplasia usually accompanies other inner ear anomalies, and the concurrent occurrence of the inner ear anomaly and the middle ear anomaly also has been reported. The purpose of this study was to investigate the LSC dysplasia among patients with middle ear cholesteatoma. MATERIALS AND METHOD: Medical record and temporal bone computed tomographic (CT) scan of cholesteatoma patients with the LSC dysplasia were analyzed retrospectively. RESULTS: There were four cases of the LSC dysplasia among 262 cholesteatoma patients (1.5%) during five years. Temporal bone CT scan showed short, dilated LSC and enlarged vestibule. The cochlea and the opposite side of the bony labyrinth were normal. All of the patients showed middle ear cholesteatoma occurring on the affected ear. Three patients showed mixed type of hearing loss, and the other one patient with Down's syndrome showed profound hearing loss on auditory brainstem response. In the velocity step test, two patients were normal, and one patient showed decreased response in the affected side. CONCLUSION: This study showed that the LSC dysplasia might be a relatively common inner ear anomaly encountered on the preoperative CT scan of cholesteatoma patients. The relationship between the LSC dysplasia and the development of middle ear cholesteatoma is not clear, and further studies are needed.