Three-dimensional approach to analysis and treatment of hemifacial microsomia.

Based on our experience with 40 patients with hemifacial microsomia (first and second branchial arch deformity), we have developed a three-dimensional analytic approach to the skeletal deformity. The sagittal plane x-ray views (lateral cephalogram and panorex) demonstrate the anatomy of the temporomandibular joint as well as the shape and height of the mandibular rami. The frontal plane is demonstrated by the anterio-posterior (A-P) cephalogram, which shows the discrepancy in ramus height and the abnormal arc of mandibular rotation toward the affected side. The transverse plane is evaluated with a submental vertex radiograph, which shows the shape of the mandibular body and medial displacement of the temporomandibular joint. Three-plane radiographic analysis demonstrates the total anatomic distortion and the abnormal growth vectors. We hypothesize that abnormal mandibular growth is of primary importance in this deformity. Application of this analysis has influenced the timing of intervention and the design of corrective procedures.