Bilateral Sagittal Split Mandibular Ramus Osteotomy Alters the Temporomandibular Joint.

ABSTRACT: In this retrospective analysis, we examined temporomandibular joint space volume and condyle position in 10 patients undergoing bilateral sagittal split mandibular ramus osteotomy plus Le Fort I osteotomy to correct mandibular asymmetry. Cone beam computed tomography was used to map temporomandibular joint prior to (T0), immediately after (T1), and at 1 year after surgery (T2). In the deviated side, we detected significant lateral shift of the condyle in 5 patients at T1, and the shift disappeared at T2. In the non-deviated side, we detected significant medial shift of the condyle in all 10 patients at T1; the shift continued in 9 patients at T2. Temporomandibular joint space volume increased significantly at T1 and returned to presurgical volume at T2. In conclusion, there is significant shift in position of condyle in majority of the patients after bilateral sagittal split mandibular ramus osteotomy. The most consistent and persisting change was medial shift on the nondeviated side.

Simultaneous Orthognathic Surgery and Mandibular Contour Osteoplasty for Treating Mandibular Protrusion With High Gonial Angle.

OBJECTIVE: The purpose of this study was to confirm the effectiveness and feasibility of simultaneous orthognathic surgery and mandibular contour osteoplasty with the help of the accurate surgical templates to treat mandibular protrusion with high gonial angle. METHODS: Ten patients diagnosed as mandibular protrusion with high gonial angle were included in this study. Besides the traditional orthognathic surgery, mandibular contour osteoplasty was performed simultaneously. Models of the mandible were fabricated via 3D printing technology. Accurate surgical templates were produced on the 3D printing model according to preoperative design. Radiographs and medical photographs preoperatively and postoperatively were taken to compare the effectiveness of the operation. Measurement items include gonial angle (Ar-Go-Me), midlines of maxilla and mandible. The clinical manifestation of the temporomandibular joint and condylar process were observed. RESULTS: Radiographs and photographs of the face were taken after surgery showed satisfactory esthetic outcomes. The right gonial angle improved from 128.20°â€Š±â€Š5.67° to 120.35°â€Š±â€Š0.46°, and the left gonial angle improved from 129.91°â€Š±â€Š2.78° to 120.74°â€Š±â€Š0.59°. The midlines of the maxilla and mandibular basically consisted of the facial midline. After surgery, patients' clinical manifestation of the temporomandibular joint was no significant difference compared with the preoperative and the condylar process had no absorption. CONCLUSION: The results of this study showed it was possible to perform orthognathic surgery and mandibular contour osteoplasty simultaneously with the help of surgical templates in the treatment of mandibular protrusion with high gonial angle.

A Modified Cosmetic Genioplasty Can Affect Airway Space Positively in Skeletal Class II Patients: Studying Alterations of Hyoid Bone Position and Posterior Airway Space.

BACKGROUND: Improving the posterior airway space is one of the most important functions of genioplasty. Studies have shown that the posterior airway space (PAS) can play an important role in the evaluation of obstructive sleep apnea syndrome (OSAS). The purpose of this study is to evaluate the airway safety of our modified technology by observing the impact on PAS in skeletal Class II patients without OSAS. METHODS: We have modified a cosmetic genioplasty, which can guarantee the continuity of the lower edge of the bilateral mandible by rotating the chin segment clockwise. Fourteen patients submitted to our modified cosmetic genioplasty alone were included in the study. The facial convexity angle and the ratio of the face were measured by analyzing photographs. The position of the hyoid bone and the width of the PAS were measured by analyzing lateral cephalograms. The volume and the cross-sectional area (CSA) of the PAS were measured using 3D reconstruction. The Wilcoxon signed-rank test and paired samples t test were used to assess the significance of differences of the data (p < 0.05). RESULTS: Soft tissue measurements were statistically different (p = 0.001) and achieved satisfactory results. The position of the hyoid bone moved up (LX: p = 0.004; LML: p = 0.056) and forward (LY: p = 0.001; LCV3: p = 0.016). The increase in the CSA had statistical significance (p < 0.005). There were significant statistical differences in the total airway volume and hypopharynx (p = 0.001), except in the oropharynx (p = 0.096). CONCLUSIONS: Our modified genioplasty not only achieved better cosmetic results by ensuring the continuity of the lower edge of the bilateral mandible but also exerted a significant positive impact on the posterior airway space for patients with skeletal class II, thus helping reduce the prevalence of OSAS. We hence suggest performing this modified cosmetic genioplasty on the skeletal class II patients with/without OSAS if necessary. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .