Extent of Middle Ear Aeration in Congenital Aural Atresia

Abstract

Objectives: To determine the extent of middle ear aeration in patients with aural atresia and to assess how aeration increases with age. To examine the role of middle ear aeration as an adjunct measure in the assessment of aural atresia and the determination of surgical candidacy for aural atresia patients. Study Design: Retrospective review of children with aural atresia in a tertiary academic pediatric otolaryngology practice. Methods: 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 cochlear implant patients, which served as a control population. Results: The average age of patients at the time CT was performed was 4.7 yrs (range <0.1-13.8 yrs). The average middle ear volume of the atretic ears was 0.34 cubic centimeters compared to an average of 0.51 cubic centimeters for the nonatretic ears. The mean ratio of the atretic to nonatretic volume was 0.67. Higher ratio of aeration was correlated with surgical candidacy. In patients who underwent serial scans, no statistically significant difference in the rates of growth was found between atretic and nonatretic ears. Finally, middle ear volume measurement correlated well with clinical grading scales. Conclusions: The middle ear volumes expand over the course of child development equally in atretic and non-atretic ears. Middle ear aeration correlates with classification systems designed to assess operative candidacy. The practitioner may be better able to assess surgical candidacy by supplementing classic atresia classification systems with middle ear volume