The Correlation Between Severity Of Microtia And Abnormal CT Findings Of Ossicular Malformation And Hemifacial Microsomia

Abstract

Background: Microtia is a congenital malformation of the pinna frequently associated with anomalies of the temporal bone and maxillofacial structures, arising from the shared embryological origin of the first and second branchial arches. In Indonesia, cases of syndromic microtia which accompanied by other congenital anomalies such as hemifacial microsomia (HFM) are more prevalent than isolated microtia. Understanding the correlation between the clinical severity of microtia and the status of the ossicles and other middle ear structures is crucial for planning complex reconstructive surgeries. Objective: To analyze the correlation between the severity of microtia, based on the Hunter classification, with ossicular malformations and the severity of hemifacial microsomia using the Pruzansky-Kaban classification via High-Resolution Computed Tomography (HRCT) of the temporal bone. Methods: This analytical observational study was conducted on 86 samples from microtia patients at Universitas Airlangga Hospital between 2020 and 2026. Microtia severity was clinically assessed using the Hunter classification, while ossicular malformations (malleus, incus, stapes) and HFM grades were evaluated using temporal HRCT by radiologists. Bivariate data analysis was performed using Spearman’s correlation and Chi-square tests with a 95% confidence interval (p<0.05). Results: Sample characteristics showed a male predominance (ratio of 1.69:1) and frequent right-sided unilateral involvement. Significant strong correlations were found between microtia severity and malformations of the malleus (r=0.748; p=0.000), incus (r=0.732; p=0.000), and stapes (r=0.722; p=0.000). A moderate correlation (r=0.410; p=0.000) was observed between microtia severity and hemifacial microsomia. The correlation with external auditory canal (EAC) anomalies was strong (r=0.733; p=0.000), whereas the association with round window anomalies was weak (r=0.381; p=0.006). Approximately 32.6% of the microtia samples were associated with HFM. Despite the evident linear correlation, individual variations were noted where mild-grade microtia could still present with complex ossicular malformations. Conclusion: The severity of microtia is significantly and linearly correlated with the degree of ossicular malformation (particularly the malleus-incus complex) and the severity of hemifacial microsomia. However, due to internal anatomical variations that do not always mirror the external clinical appearance, temporal HRCT remains a mandatory modality for the preoperative evaluation of microtia.