Surgery-First Orthognathic Surgery for Severe Facial Asymmetry Combined With Mandibular Distraction Osteogenesis Using a Three-Dimensional Internal Distractor

: Severe facial asymmetry in adults with hemifacial microsomia or other types of mandibular hypoplasia is challenging to treat with simultaneous maxillomandibular distraction osteogenesis using an external distractor combined with intermaxillary fixation (IMF). Using an external distractor also produces significant distress for patients for at least 8 weeks. Furthermore, mandibular-driven distraction tends to elongate the midface, with difficulty positioning of the center of the maxilla in the center of the face and horizontalization of the occlusal plane. To overcome these disadvantages, the authors performed repositioning of the Le Fort I segment intraoperatively to restore maxillary roll levering, followed by mandibular distraction using a 3-dimensional internal distractor with a variable angle for better control and tolerable postoperative distraction osteogenesis. This approach is based on the surgery-first concept. During the operation, the Le Fort I segment was fixed centrally in the center of the face and horizontally in the occlusal plane based on a computer-aided surgical simulation. Before mandibular corticotomy, a 3-dimensional internal distractor was placed on the affected side. Finally, vertical ramus osteotomy of the unaffected side was performed. After completion of distraction with IMF using elastic bands, IMF was released. The distractor was removed after a 6-month postoperative consolidation period. This method has been used in 5 patients with severe facial asymmetry, which were all successfully treated without complication. These cases show that this method can be used for severe facial asymmetry in adults, based on the surgery-first concept of minimizing the duration of orthodontic treatment and optimizing facial aesthetics.