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

Changes of temporomandibular joint space volume during 1 year after transoral vertical ramus osteotomy in patients with mandibular asymmetry

This retrospective study aimed to evaluate the difference in the temporomandibular joint (TMJ) space volume between the deviated (Dev) and non-deviated (NDev) side following transoral vertical ramus osteotomy (TOVRO) in patients with mandibular prognathism combined with asymmetry using reconstructed 3-dimensional images. Sixty joints from 30 patients who underwent TOVRO between January 2018 and December 2021 were included. Computed tomography (CT) or cone-beam CT was performed before surgery (T0), and 6 (T1) and 12 months postoperatively (T2). The volume of the overall joint space (Vjs) and its compartments (i.e., the anterior, posterior, medial, and lateral joint spaces) were calculated at each time point. A linear mixed model and repeated-measures covariance pattern with unstructured covariance were used. Vjs increased at T1 compared to T0 and decreased at T2 compared to T1 (p < 0.0001). Furthermore, the volume changes over time were statistically significant in all compartments (p < 0.05); however, there was no significant difference in the Vjs and its compartments between the Dev and NDev side over time (p > 0.05). Adjustments for sex and mandibular movements did not affect the results. This study can provide the basis in TMJ spatial change and predicting the prognosis after TOVRO in facial asymmetry.

Three-dimensional Analysis of Skeletal Stability in Cleft Lip and Palate Patients Undergoing Bimaxillary Surgery With Le Fort I Osteotomy and Intraoral Vertical Ramus Osteotomy

Orthognathic surgery in patients with lip and palate clefts is challenging owing to scar tissue from primary repairs and severe deformities. In this study, we evaluated the stability of Le Fort I osteotomy with intraoral vertical ramus osteotomy (IVRO) in patients with cleft lip and palate using 3-dimensional (3D) analysis. This retrospective study comprised 14 cleft lip and palate patients (3 females, 11 males; the average age at surgery: 23.8 y) who underwent bimaxillary orthognathic surgery involving Lefort I osteotomy and IVRO. Cone-beam computed tomography (CBCT) images were obtained at preoperative (T0), 1-month postoperative (T1), and 1-year follow-up (T2) periods. The 3D analysis assessed the transitions and rotations of the maxilla and mandible using a virtual triangle. The maxilla showed stability in all directions at the 1-year follow-up with minimal relapse. The distal segment of the mandible exhibited clinically acceptable anterior (1.15 mm relapse) movements and pitch rotation (2.88° counterclockwise relapse) during the first year postoperatively. The proximal mandibular segment underwent anterior-inferior transition (1.21 and 2.01 mm, respectively) and lateral-outward rotation (4.90° and 7.51°, respectively) postsurgery, remaining unchanged 1 year postoperation. Le Fort I osteotomy with IVRO provides skeletal stability in patients with cleft lips and palates. This study demonstrated a minimal maxillary relapse and clinically acceptable movements in the distal mandibular segment during the first postoperative year. The proximal mandibular segment moved anteriorly and inferiorly, rotated laterally and outward after surgery, and remained unchanged at the 1-year follow-up.

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.