Association between Ear Position in Microtia and Middle Ear Development in 3-Dimensional Computed Tomography Imaging

A correlation between auricular deformity in microtia and middle ear development is recognized, but inconsistencies remain, particularly in cases where patients with severe auricular deformity have well-developed middle ears. This suggests that anatomical features beyond auricle shape may be more closely related to middle ear formation.

Using 3-dimensional computed tomography scans, we evaluated 221 auricles from 188 patients with microtia. The concave part between the upper and lower auricular components was defined as auricular concavity. Auricles were then classified based on the vertical relationship of the auricular concavity to the zygion: the upper position group (at or above the zygion) or the lower position group (below the zygion). Jahrsdoerfer scores were compared between groups.

The upper position group had a significantly higher mean Jahrsdoerfer score (8.1) than the lower position group (4.2), with a 1-sided P < 4.0 × 10 -16 ( df = 72.2), indicating a strong association between auricle position and middle ear development.

The auricle's vertical position, particularly the auricular concavity relative to the zygion, is significantly associated with the degree of middle ear development. Based on external anatomical landmarks, this simple assessment can be performed without computed tomography imaging, may serve as an early indicator of candidacy for middle ear reconstruction, and offers a useful clinical tool for surgeons and nonsurgical providers, enabling earlier counseling for patients and families regarding the potential for hearing improvement through surgery.