Microtia grade as an indicator of middle ear development in aural atresia.

OBJECTIVE: To correlate the appearance of the external ear with the development of the middle ear in patients with congenital aural atresia.

DESIGN: Retrospective analysis of patients with congenital aural atresia. Obtain the microtia grades assigned to affected ears and correlate them with atresia scores that describe the degree of the middle ear malformation.

SETTING: University of Texas-Houston Otolaryngology Clinic (1988 to 1992).

PATIENTS: A total of 199 ears with congenital microtia and aural atresia and 25 ears with canal stenosis without microtia were identified, all of which had been previously evaluated by high-resolution computed tomography of the temporal bone, and then assigned an atresia score. Patients with Treacher Collins syndrome were not included in our study.

RESULTS: The average atresia score in cases with grade I microtia was 8.5; grade II microtia, 7.2; and grade III microtia, 5.9. In cases with canal stenosis without microtia, the average atresia score was 8.3.

CONCLUSION: The better developed the external ear, the better developed the middle ear.