Hemimandibular hyperplasia: classification and treatment algorithm revisited.

Hemimandibular hyperplasia (HH) is a developmental asymmetry characterized by three-dimensional enlargement of one half of the mandible. The hyperplastic side usually involves the condyle, condylar neck, ramus, and body, with the anomaly terminating abruptly at the symphysis. The malformation results in the clinical presentation of ipsilateral enlargement of the mandible and tilted occlusal plane, associated with a deviated chin to the contralateral side. Since the first case report of HH in the English literature in 1836, various terminology and classifications were used. In this study, the authors classified the patients into typical and atypical types of HH on the basis of clinical and radiologic observations in an effort to achieve a simplified and efficient surgical management on the basis of the severity of deformity. Accordingly, surgical treatments are designed respectively on the basis of the authors' classification and treatment algorithm. In addition, in view of potential complications arising from condylectomy, none of the patients had undergone condylectomy as part of the surgical treatment. The authors present their experience on the basis of this proposed classification and treatment algorithm with functional and aesthetic outcomes as the end points of this study.