Sensorineural hearing loss: There is no correlation with isolated dysplasia of the lateral semi-circular canal on temporal bone CT

Background: Inner ear malformations may cause sensorineural hearing loss (SNHL). However, the correlation between the small lateral semi-circular canal (LSCC) and SNHL is controversial. Purpose: To determine whether there is a correlation between the two using CT-based measurement. Material and Methods: We retrospectively reviewed the high-resolution CT images of the temporal bone obtained from consecutive patients. A total 136 ears of 68 patients (25 men and 43 women; age range 20-85 years, mean 49.8 years) were included in this study. Patients whowere clinically suspected to have otosclerosis were also excluded. Two radiologists independently measured the width and cross-sectional area of the bony island of LSCC. We evaluated the correlation between LSCC bone island width or cross-sectional area and hearing level in all cases using Pearson correlation co-efficients. In addition, we compared hearing levels among the patient group with normal-sized LSCC (≥mean-SD), small LSCC (<mean-SD) and very small LSCC (<mean-2SD) as defined by the width and cross-sectional area of the bony island using Student's t-test. Results: A total 136 ears of 68 patients (25 men and 43 women; age range 20-85 years, mean 49.8 years) were included in this study. No significant correlation was shown between LSCC bony island width or crosssectional area and hearing level (P > 0.05). No significant difference in hearing levels were found among groups of the normal-sized, small and very small LSCC (P > 0.05). Conclusion: We conclude that there is no correlation between isolated small LSCC and SNHL.