Analyzing Discrepancies and Correlations in Soft and Hard Tissue Asymmetry: A Focused Study on Hemifacial Microsomia and Isolated Microtia

Background: This study aims to thoroughly investigate the distinctions and relationships between facial hard and soft tissue asymmetry, as well as their variations within different conditions and age groups.

Methods: This cross-sectional study analyzed pre-treatment computed tomography (CT) images from 120 male patients aged 5 to 12 years with unilateral HFM (Pruzansky-Kaban types I and IIA) or isolated microtia. The 120 patients were categorized into four groups by condition (HFM or isolated microtia) and age (5-7, 8-12 years). Segmentation and extraction of anatomical landmarks were performed using Mimics software, followed by generating root-mean-square (RMS) values for facial asymmetry. Statistical analysis, including the Wilcoxon signed-rank test and Spearman correlation coefficient, was conducted to assess differences and correlations in asymmetry.

Results: The study found that soft tissue asymmetry was generally greater than hard tissue asymmetry across all facial regions. The complexity of regional asymmetry correlations increased with age in HFM patients but decreased in isolated microtia patients. Significant correlations between hard and soft tissues were observed within the same anatomical regions, particularly in HFM patients aged 8-12 years.

Conclusion: The intricate interplay between hard and soft tissues was observed in HFM and isolated microtia patients. Personalized analysis of the causes of asymmetry in different regions is crucial for the formulation of effective treatment plans.

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