A comparison of two classification systems for hemifacial microsomia

Area of Science:

• Craniofacial anomalies
• Medical classification systems
• Genetics and developmental biology

Background:

• Hemifacial microsomia (HFM) classification is crucial for clinical management but challenged by etiological and phenotypic heterogeneity.
• Existing classification systems require evaluation to accurately capture the spectrum of HFM.
• Accurate classification impacts diagnosis, treatment planning, prognosis, and research data evaluation.

Purpose of the Study:

• To examine and compare the OMENS and SAT classification systems for hemifacial microsomia.
• To identify limitations and suggest improvements for existing HFM classification methods.
• To better understand the phenotypic heterogeneity of hemifacial microsomia.

Main Methods:

• Retrospective analysis of data from 50 hemifacial microsomia patients.
• Comparative evaluation of the OMENS (Oculo-Mandibulo-Dento-Aural-Nerve) and SAT (Skeletal, Aural, and Tracheal) classification systems.
• Assessment of concordance with existing literature and identification of phenotypic variations.

Main Results:

• Both OMENS and SAT systems capture major craniofacial defects in hemifacial microsomia.
• The OMENS system offers refined differentiation of soft tissue/nerve and orbital/mandibular defects.
• Neither system currently includes grading for auricular tags or deafness, despite tag prevalence (34%) and clinical relevance.

Conclusions:

• The OMENS system provides a more detailed classification of craniofacial defects in hemifacial microsomia.
• Auricular tags should be considered and graded as minor ear malformations in HFM classification.
• The OMENS system can be enhanced (e.g., OMENS*) to indicate significant non-craniofacial anomalies, improving phenotypic spectrum representation.