ABSTRACT
Hemifacial microsomia is the second most common congenital anomaly of the craniofacial region. Abnormal development of the structures derived from the first and second branchial arches results in unilateral hypoplasia and asymmetry of the orbit, mandible, ear, cranial nerve VII and overlying soft tissue. Extracranial anomalies may occur. The characteristic finding of hemifacial microsomia, including bilateral involvement, is the asymmetry in craniofacial development. Many patients tend to posture the head towards the affected side or may have musculoskeletal restrictions. In such cases, the patient should be examined in resting and corrected position with the horizontal facial plane established. Skin markings may help establish the facial planes. Advanced technology is allowing for surgical treatment planning using virtual surgery software. The chapter describes the more conventional treatment planning method. Conventional model surgery is then performed on plaster models of the patient mounted in a semi-adjustable articulator.
