Three-dimensional changes of proximal segments in facial asymmetry patients after bilateral vertical ramus osteotomy

Recent Trends in Orthognathic Surgery in Asia

Anatomy and standards of beauty are different between Asians and Westerners. Unlike Westerners, Asians have a wide and prominent jaw shape but prefer a slim and soft face shape. To achieve this goal, maxillary setback and/or posterior impaction surgeries are popular among upper jaw surgery, and various adjuvant surgeries are performed simultaneously on the mandible to obtain the so-called oval shape or V-line face. In addition, according to the development of virtual surgery software and orthodontic treatment techniques, the surgery-first approach is now accepted as a reliable option for orthognathic surgery if it is indicated.

The outcome of skeletofacial reconstruction with mandibular rotation for management of asymmetric skeletal class III deformity: A three-dimensional computer-assisted investigation

The mandibular proximal ramus segments should be moved and rotated during orthognathic surgery-based skeletofacial reconstruction for the correction of challenging patients with facial asymmetry and malocclusion, but quantitative data regarding this rotation were not sufficient to date. This 3D computer-assisted study measured the proximal ramus segment rotation after 3D simulation-guided two-jaw surgery in patients with facial asymmetric deformity and class III malocclusion (n = 31). Using 3D mandible models and a reliable proximal ramus segment-related plane, angular changes in pitch, roll and yaw directions were measured before and one month after surgery. Significant rotational changes (p < 0.01) were observed in the left and right sides and overall proximal ramus segments after surgery, with absolute differences of 4.1 ± 3.0 (range −7.8 to 6.9), 2.8 ± 2.3 (−8.8 to 5.0), and 2.7 ± 2.4 (−6.6 to 9.9) degrees in pitch, roll, and yaw rotations, respectively. Numbness and mouth opening limiting occurred within the first 6 months after surgery but the patients had an unremarkable long-term postoperative course, with no revisionary surgery required. This study contributes to the multidisciplinary-related literature by revealing that proximal ramus segment rotation and rigid fixation with no postoperative intermaxillary immobilization was practicable in skeletofacial surgery for the successful treatment of asymmetric deformity and class III malocclusion.