Purpose: Distraction osteogenesis (DO) has become an accepted method of treatment for patients requiring mandibular lengthening due to congenital malformations. However, the skeletal growth pattern of a distracted mandible on long-term basis has still not been clearly shown in the literature. The purpose of this presentation is to put forth growth pattern of hemifacial microsomia for consideration by analyzing the dentofacial changes observed during a 10-year follow-up period, in a case treated by mandibular distraction osteogenesis.
Subject and Method: Twelve years old girl with Pruzansky-Kaban Type IIB right hemifacial microsomia, who had undergone DO with an external device. The analysis of the morphological changes during the observation period was based on panoramic radiographs, posteroanterior and lateral cephalograms.
Results: Marked amount of lengthening and a significant improvement in mandibular symmetry were achieved during the active phase of mandibular distraction. The ratio between the ramus heights of the affected side and the normal side improved significantly in the affected side's favor as the mandible was lengthened, but this ratio turned back to its initial value at the end of 10 years observation period.
Conclusion: Although there was some amount of growth at the affected side during the follow-up period, this was not enough to catch up with the growth of the condyle at the normal side. Therefore, the asymmetry reoccurred as a consequence of growth pattern in the growing hemifacial microsomia case of this report.