Middle ear volume as an adjunct measure in congenital aural atresia

Objective: To examine middle ear volume in patients with aural atresia and investigate the role of middle ear volume as an adjunct measure in determining surgical candidacy. Methods: We performed a retrospective review of children with aural atresia in a tertiary academic pediatric otolaryngology practice. High resolution multiplanar CT scans of the temporal bones were analyzed for middle ear volume and staged according to existing clinical grading scales. Atretic ears were compared to the nonatretic ears of the same patient as well as to ears of a control population. Results: The average age of patients at the time CT was performed was 4.7 years (range <0.1-13.8 years). The average middle ear volume of the atretic ears was 0.34. cc compared to an average of 0.51. cc for the nonatretic ears. The mean ratio of the atretic to nonatretic volume was 0.67. In patients who underwent serial scans, no statistically significant difference in rates of growth existed between atretic and nonatretic ears. Finally, measures of middle ear volume correlated well with clinical grading scales. Conclusions: Both middle ear volume and the ratio of the atretic volume to nonatretic volume serve as useful adjunct measurements in determining surgical candidacy. The practitioner may be better able to assess surgical candidacy by supplementing classic atresia classification systems with middle ear volume measurements.