Hemifacial microsomia: a multisystem classification.

Variability of deformities in hemifacial microsomia has precluded the general acceptance of any classification based on one reference organ. We present a review of hemifacial microsomia classifications and propose a TNM-style multisystem classification. This alphanumeric coding system, SAT, provides cohesion to existing hemifacial microsomia classifications. The acronym SAT is derived as follows: S = skeletal, A = auricle, and T = soft tissue. There are five levels of skeletal deformity (S1 through S5), four levels of auricular deformity (A0 through A3), and three levels of soft-tissue deformity (T1 through T3). Hence a patient with minimal deformity would be classified S1A0T1, whereas a patient with the most severe deformity would be S5A3T3.