The round window diameter in congenital aural atresia and comparison with sensorineural hearing loss and control group

The aim of this study was to measure round window (RW) diameters in patients with congenital aural atresia (CAA) or sensorineural hearing loss (SNHL) and a normal control group and to analyze whether differences exist between these groups. Temporal bone computed tomographic scans of 12 patients with CAA (5 males, 7 females) aged 1 to 50 years (median age, 6 years), 12 patients with SNHL (8 males, 4 females) aged 2 to 32 years (median age, 5 years), and 11 patients (3 males, 7 females) aged 2 months to 53 years (median age, 8 years) randomly selected from a pool of patients with unilateral chronic otitis media or cholesteatoma were reviewed. We measured RW diameter on oblique reconstruction planes. To prevent possible individual differences, skull width was measured. There were no statistically significant differences between all groups for skull width. Both RW diameter and RW membrane width were found smaller in the CAA group than both SNHL group and control group with statistical significance, whereas there were no statistically significant differences between the SNHL group and the control group. We found that both the RW diameter and RW membrane width in CAA were smaller than those in the control group. If this finding is supported in future studies, the production of floating mass transducer with different sizes may be useful. We suggest that RW diameter should be measured in each patient before operation and thus a floating mass transducer with the appropriate caliber should be chosen.