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Aim: The purpose of this study was to evaluate the effect of adding a fourth osteotomy at the lower border of the mandible on the lingual cortical fracture pattern in bilateral sagittal split ramus osteotomies., Patients and Methods: The sample of the study consisted of 20 patients (12 male and 8 female, with a mean age of 26.79 ± 7.12 years) with mandibular deformities who needed bilateral sagittal split ramus osteotomy. One side underwent a traditional sagittal split ramus osteotomy, and the procedure was modified on the other side by adding a 1 cm horizontal osteotomy at the lower border of the mandible, just distal to the caudal end of the vertical buccal osteotomy cut. A 3D CBCT was used to identify the split pattern., Results: In the total sample, 40% of the lingual splits ran vertically toward the lower border of the mandible (LSS1), 20% of the splits passed horizontally to the posterior border of the mandible (LSS2), 32.5% of the splits took place along the inferior alveolar canal (LSS3), and 7.5% of the splits were unfavourable fractures (LSS4). On the inferior border osteotomy sides, the distribution of LSS1, LSS2, LSS3, and LSS4 was 10 (25%), 6 (15%), 4 (10%), and 0 (00), respectively. Their distribution on the sides without inferior border osteotomy was 6 (15%), 8 (20%), 13 (32.5%), and 3 (7.5%), respectively. Statistical analysis revealed a significant difference between the two groups (p < 0.05)., Conclusion: Inferior border osteotomy tends to direct the lingual split fracture line toward the lower and posterior borders of the mandible and minimizes bad splits; however, further studies are needed to confirm our findings., (© 2023. The Author(s).)

Introduction: This study aimed to compare postsurgical stability between conventional (CSA) and surgery-first (SFA) approaches and investigate its prognostic factors in patients with a skeletal Class Ⅲ extraction., Methods: Twenty and 19 patients treated with LeFort I osteotomy and bilateral sagittal split ramus osteotomy (BSSRO) with premolar extraction were enrolled in SFA and CSA groups, respectively. Serial cone-beam computed tomography images obtained before surgery, immediately after surgery (T1), 3 months after surgery, and 12 months after surgery were used for 3-dimensional quantitative analysis. The condyle was segmented for analyzing volumetric changes. Repeated measures analysis of variance, independent t test, and chi-square test were used to compare time-course and intergroup differences. Pearson and Kendall correlation and multivariate linear regression analyses were used to explore prognostic factors affecting skeletal stability., Results: In both CSA and SFA, postsurgical relapse mainly occurred in the mandible sagittal and vertical dimensions and during the first 3 months after surgery. Stability in SFA was significantly less than that in CSA. Intraoperatively, inferolateral condylar displacement with proximal segment inwards, clockwise rotation, and return movements after surgery were observed regardless of the treatment approach. The condylar volume remained stable over time. Multivariate regression analysis showed that posterior vertical dimension (VD) at T1 (-1.63 mm), surgical amount of mandibular setback (-10.33 mm), surgical condylar downwards displacement (-1.28 mm), and anterior overjet at T1 (6.43 mm) were the most important predictors of early mandibular relapse (r 2  = 0.593)., Conclusions: The risk of early relapse could be reduced by controlling the anterior, middle, and posterior constraints provided by the prediction model., (Copyright © 2023 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)

The aim of this study was to identify clinical factors associated with progressive facial swelling after orthognathic surgery. Patients diagnosed with jaw deformities and undergoing orthognathic surgery were retrospectively evaluated, and those with surgical site infection, Le Fort I osteotomy, or genioplasty only were excluded. Facial swelling volume was calculated by comparing facial volume preoperatively and three days postoperatively using 3D images and image analysis software (VECTRA H2). FXIII was measured within three days after surgery in only patients with unexplained postoperative bleeding or hematoma. The correlation between facial swelling volume and clinical factors was statistically analyzed. Facial swelling volume was examined in 78 patients. Univariate analysis showed a significant difference between facial swelling volume (mean = 41.6 cm 3 ) and operation time (mean = 209.3 min, r = 0.283, p = 0.012), ΔHb level (mean = 1.18 g/dL, r = 0.235, p = 0.039), as well as decreased factor XIII activity (mean = 75.3%, p = 0.012). Multivariate analysis showed a significant difference between facial swelling volume and FXIII deficiency (standard error = 6.44, p = 0.031).Progressive facial swelling immediately after orthognathic surgery may be due to factor XIII deficiency., Competing Interests: Declaration of competing interest There are no conflicts of interest to disclose in this article., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Condylar adaptations following orthognathic surgery remain an area of interest. Prior studies do not use 3-dimensional imaging modalities and lack standardization in the choice of osteotomy and movement when assessing condylar changes., Purpose: The purpose of this study was to use 3-dimensional cephalometry to measure the association between osteotomy type (sagittal split osteotomy [SSO] vs vertical ramus osteotomy [VRO]) and changes in condylar volume and position., Study Design, Setting, and Sample: This is a retrospective cohort study from January 2021 through December 2022 of patients at Bellevue Hospital in New York City, New York who were treated with either SSO or VRO for the correction of Class III skeletal malocclusion., Predictor/exposure/independent Variable: The primary predictor was the type of mandibular osteotomy, sagittal split osteotomy, and vertical ramus osteotomy., Main Outcome Variables: The primary outcomes were changes in condylar volume (change measured in mm 3 ) and relative position (anterior-posterior change utilizing the Pullinger and Hollinder method)., Covariates: Covariates included patient age, sex, setback magnitude, temporomandibular joint symptoms, and fixation method for SSO patients., Analyses: Univariate comparisons were performed between independent variables and study outcomes. Volume changes were compared within each predictor using paired t-tests. Position changes were compared within each predictor using χ 2 tests. If there were multiple significant univariate predictors, multiple regression models were created to predict volume and position changes. A P < .05 value was considered statistically significant., Results: The final sample comprised 30 condyles derived from 30 subjects. Mean age was 22.7 years (SD = 5.7) and mean setback was 3.9 mm (SD = 0.9). Twenty two condyles (73.3%) were subject to SSO with fixation, while the remaining 8 (26.7%) condyles were subject to intraoral VRO without fixation. When compared to VRO, condyles manipulated with SSO had greater volume loss (-177.2 vs -60.9 mm 3 ; P = .03) and positional change (68.2 vs 12.5%; P < .01). Self-reported measures of postoperative pain, internal derangement, and myofascial symptoms were not significantly associated with either volume or positional changes., Conclusions and Relevance: The SSO resulted in greater postoperative condylar volume loss and positional changes. These volume and positional changes were not correlated with self-reported temporomandibular disorder symptoms., (Copyright © 2023 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

The bilateral sagittal split osteotomy (BSSO) is the most popular orthognathic procedure performed by maxillofacial surgeons to treat skeletal class II and class III and to correct mandibular asymmetries. The study aimed to evaluate the lingual splitting patterns and lateral bone cut end (LBCE) in bilateral sagittal split osteotomy (BSSO) and their relation with the ramal thickness and the presence of impacted third molars using cone beam computed tomography (CBCT). This prospective observational study included patients with mandibular prognathism who were treated with BSSO with or without Le Fort I osteotomy. Cone beam computed tomography was used to measure the ramal thickness preoperatively and to evaluate the LBCE, and the lingual splitting patterns postoperatively. Twenty-one patients (42 sides) were included in this study. The most commonly observed lingual splitting pattern was type III (47.6%), while the most common LBCE was type B (59.5%). The bad split was encountered 8 times on 42 sides (16.7%). A nonsignificant relationship between the ramal thickness and bad splitting was observed ( P =0.901). Impacted third molars were present in 16 of the 42 sides (38.1%) and had no significant effect on the occurrence of bad splitting ( P =0.063). Type III lingual splitting pattern and type B LBCE were the most commonly observed patterns. No direct association was observed concerning the presence of impacted mandibular third molars and the thickness of the ramus with the occurrence of bad splitting., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 by Mutaz B. Habal, MD.)

Objective: The objective of this study was to investigate of the effect of piezzo and conventional osteotomy techniques on bone reserve in the osteotomy line and comminuted fracture ratios that is able to compromise bone to bone contact negatively., Methods: Bilateral sagittal split ramus osteotomy was performed on 12 fresh male Thracian curly caprine mandible. In the first group (n: 12) osteotomies were performed with piezzo device. In the second group (n: 12) osteotomies were performed with micromotor and manual osteotomes. Operative time was measured. The number of comminuted fractures, length and width of the osteotomy, and the space between the osteotomy lines was evaluated from 3-dimensional computed tomography scans., Results: The mean value of procedure duration was 320.4±10.76 seconds for piezo osteotomy and 238.8±8.29 seconds for conventional micromotor ( P <0.0001). Number of comminuted fractures was 1.41±1.3 in piezoelectric group, 1.5±1.3 in conventional group and the difference was not statistically significant (p: 0,88). Osteotomy lengths and widths were 35.58±5.2, 2.196±1.9 and 36.23±5.05, 2.27±1.85 in the piezzo and conventional groups, respectively. (p lengths :0,75; p widths :0,92) The volume of the bony interface between the distal and proximal segments of the mandible after osteotomy was 166.3±184.2 mm 3 in the piezzo group and 163.5±129.3 mm 3 in the conventional group (p: 0,96)., Conclusion: The piezo surgery and the conventional osteotomy were found to be similar in terms of the gap between the distal and proximal mandible and the number of comminuted fractures. The duration to perform the conventional osteotomy was found to be shorter than the piezo surgery., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 by Mutaz B. Habal, MD.)

Background: The aim of this study was to evaluate the stress occurring in the fixation systems both developed in various geometric designs for this study and currently used in sagittal split ramus advancement osteotomy using finite element analysis., Material and Methods: The finite element model that imitates three-dimensional sagittal split advancement osteotomy was fixed in 10 different miniplate fixation methods: one miniplate fixed with four monocortical screws in a horizontal and oblique pattern; four-hole two miniplates with eight monocortical screws; five-hole miniplate fixed with four monocortical and one bicortical screws; six-hole straight and curved miniplates fixed with six monocortical screws in different geometric designs. Unilateral masticatory muscle loads that have previously determined in the literature were applied to the model at the anatomical muscle attachment regions and the data obtained from finite element analysis and static linear analysis methods were recorded as Von mises, maximum principle and minimum principle stress values., Results: It was observed from the results that maximum stress occurred in Group 1, which consisted of double backward T-shaped miniplate with 6-holes and, minimum stress occured in group 10, which mimiced hybrid system with one miniplate and four monocortical and one bicortical screws., Conclusions: Based on our results, the stress on the miniplates changes according to the geometric designs and the stress on the miniplate decreases as the numbers of miniplates and bars increase. The hybrid miniplate may be preferred by the surgeon as it will be exposed to less stress in excessive mandibular advancements by using the advantages of both the miniplate and the bicortical screw.

Purpose: To analyze the morphological changes of the upper airway and related influencing factors in patients with skeletal Class Ⅲ malocclusion after bimaxillary surgery., Methods: Twenty skeletal Class Ⅲ patients who underwent Le Fort I osteotomy and bilateral sagittal split ramus osteotomy(BSSRO) for maxillary advancement and mandibular setback were selected. The patients received CT scans before(T0) and 3-6 months after surgery, and the images were reconstructed three-dimensionally with Dolphin Imaging 11.9 software. Changes in the volume, cross-sectional area, and landmarks of each soft and hard tissue of the airway were measured. Statistical analysis of the data was performed using SPSS 25.0 software package., Results: The volume of nasopharyngeal airway increased after operation (P＜0.05), and the volume of oropharyngeal airway decreased significantly(P＜0.01). The cross-sectional area of the airway at the plane of the second cervical vertebra was significantly decreased (P＜0.01), and the coronal and sagittal diameters were decreased(P＜0.05). The change of nasopharyngeal airway volume was moderately positively correlated with the sagittal change of the posterior nasal spine (r=0.460, P＜0.05), and the change of oropharynx and laryngopharyngeal airway volume was positively correlated with the vertical change of the midpoint of the soft palate(r=0.496, 0.696, P＜0.05). The airway cross-sectional area in the second and third cervical vertebra planes and the sagittal diameter of the airway in the third cervical vertebra plane were positively correlated with the vertical changes of the midpoint of the soft palate(r=0.474, 0.629, 0.547, P＜0.05). The change of airway cross-sectional area at the third cervical vertebra plane was moderately negatively correlated with the change of mandibular plane angle(r=-0.536, P＜0.05)., Conclusions: The volume and cross-sectional area of oropharyngeal airway in skeletal Class Ⅲ patients after bimaxillary surgery will decrease. However, the total upper airway volume doesn't change significantly. The changes in the upper airway are correlated with the changes in some soft and hard tissue landmarks.

Orthognathic surgery is highly effective in improving overall facial esthetics, in addition to achieving an ideal occlusion. Sagittal split ramus osteotomy (SSRO) of the mandible is the mainstay of modern orthognathic surgery, but intraoperative injury to the inferior alveolar nerve (IAN) remains one of the common complications. The authors report a case of 19-year-old male patient with left cleft lip and palate who received orthognathic surgery involving SSRO. The patient's right IAN ran close to the outer cortex of the mandible, but SSRO was successfully performed without injuring the nerve. Detailed preoperative evaluation using computed tomography images is essential. Blind splitting maneuvers during SSRO may cause IAN injury, and direct visualization inside the ramus helps to prevent injury to the nerve. Sagittal split ramus osteotomy could be considered as a viable option even when the IAN runs close to the outer cortex. This article describes SSRO procedures, highlighting the methods to avoid nerve injury., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 by Mutaz B. Habal, MD.)

In this paper, an innovative technique for resection and reconstruction of the temporomandibular joint by sliding vertical ramus osteotomy using only a submandibular approach is presented. Before pulling the posterior mandibular border slightly downward to expose parts of the condyle, the vertical ramus osteotomy was performed. With the help of 3D simulation and surgical templates, the condylectomy was carried out using the ultrasonic osteotome through the submandibular approach. Our technique achieved the desired results while preventing complications of facial nerve paralysis, the occurrence of Frey syndrome, and the preauricular scar. Therefore, we suggest that this surgical method represents an alternative treatment option for temporomandibular joint lesions., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 by Mutaz B. Habal, MD.)

This study included 46 patients with class II malocclusion ranging in age from 19 to 39 years old treated with bilateral sagittal split ramous osteotomy (BSSRO). Left and right temporomandibular joints (TMJs) of each subject were evaluated independently with cone-beam computed tomography (CBCT) before operation (T1), 1 week after operation (T2), and 1 year after operation (T3) and assessed the effects of orthognathic surgery (OGS) on the temporomandibular joint disease (TMD) symptoms. Temporomandibular joint morphology evaluation included condylar volume, condylar area, cortical bone thickness, depth of the mandibular fossa, fossa thickness, joint nodule angle, joint space, and condyle-fossa relationship, which were calculated by using the Mimics software and 3-matic software. Data were statistically analyzed with SPSS software (P <0.05 means statistically significant). In our study, bilateral TMJs have no difference in T3. Bilateral sagittal split ramous osteotomy had no significant effect on the articular fossa. The condyle volume and surface area decreased from T1 to T3, but the cortical thickness of the bone did not change significantly. More anterior condyle positions in T1 and more posterior in T3.21 patients had at least 1 sign or symptom of TMD in T1 and 27 patients in T3. Four patients who were asymptomatic in T1 developed pain after surgery, 10 developed noises, 12 showed limited mouth opening, and 8 had abnormal opening patterns. It is concluded that more condylar posterior position after BSSRO and the reduction of condyle may be related to the enlargement of anterior space. The number of patients with joint symptoms increased postoperative, and the impact of BSSRO on TMD may be negative., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 by Mutaz B. Habal, MD.)

With the advancement of digital technology over the last few decades, the use of virtual surgical planning and fabrication of surgical guides have tremendously improved the outcomes of various maxillofacial surgical procedures. The intraoral vertical ramus osteotomy (IVRO) is an orthognathic surgical procedure largely employed for mandibular setback in correcting dentofacial deformities. This study describes the design and application of a surgical cutting guide for IVRO. The guide can also be used to facilitate the placement of miniplate fixation. The initial experience at the authors' centre suggests that the guide has allowed the osteotomy to be performed with increased precision and confidence. Furthermore, the use of miniplate fixation decreased the period of maxillomandibular fixation. However, a larger series is required to evaluate the utility of this system more thoroughly., (Copyright © 2022 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Objectives: This study aimed to evaluate the surgically impacted trabecular changes in mandibular osteotomy lines and mandibular condyles after bilateral sagittal split ramus osteotomy using the fractal analysis method., Materials and Method: The study population consisted of 30 patients (9 male, 21 female) diagnosed with mandibular prognathism and operated with bilateral sagittal split ramus osteotomy under general anesthesia. Fractal analyses observed the alterations on the trabecular structure of osteotomy lines, and mandibular condyles on panoramic radiographs obtained preoperatively, postoperatively, 1st week, 6th month, and 12th month. The box-counting method was used to evaluate the changes in trabecular structure by fractal analysis. P-values of less than 0.05 were considered significant., Results: The fractal dimension values in both osteotomy lines and mandibular condyles were significantly decreased on postoperative 1st week regarding preoperative values. However, fractal dimension values commenced increasing in the following postoperative period. The fractal dimension values of the horizontal and vertical osteotomy lines reached their preoperative values on postoperative 6th and 12th month, respectively. The decreased fractal dimension values observed in the early postoperative period in the right and left condyles reached their preoperative values at the 6th postoperative month., Conclusion: Fractal analyses performed postoperatively can provide information about trabecular changes and bone healing of structures such as osteotomy lines directly affected by bilateral sagittal split ramus osteotomy and indirectly affected mandibular condyles. The results support that fractal analysis can be used together with clinical data in the evaluation of bone healing process., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Segmental mandibular advancement (SMA) consists of a combination of bilateral sagittal split osteotomy, anterior subapical osteotomy with extraction of the first premolars, and genioplasty, to allow an extended advancement of the mandible for the improvement of tongue base obstruction in moderate-to-severe obstructive sleep apnoea (OSA) and to minimize any unfavourable aesthetic change due to the large jaw advancement. The aim of this pilot study was to evaluate the surgical outcomes and complications following SMA in OSA patients. Twelve patients (nine male, three female) underwent SMA as part or whole of their skeletal advancement procedure for OSA. The apnoea-hypopnoea index (AHI) improved from a mean± standard deviation 42.4 ± 22.0/hour preoperatively to 9.0 ± 17.4/hour at 1 year postoperative. Surgical success (50% reduction in AHI) was achieved in 11 of the 12 patients (91.7%) at 1 year postoperative, while seven patients (58.3%) attained surgical cure (AHI<5/hour). The lowest oxygen saturation (LSAT) increased from a mean 73.3% preoperatively to 78.7% at 1 year postoperative. The airway volume increased from a mean 2.4 ± 1.7 cm 3 at baseline to 6.7 ± 3.5 cm 3 at 1 year postoperative (P < 0.001). No major complication occurred. This pilot study showed that SMA appears to be safe and effective as part or whole of the skeletal advancement surgery for moderate-to-severe OSA., (Copyright © 2022 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Objective: To evaluate 3D condylar displacement and long-term remodeling following the correction of bimaxillary protrusion by anterior segment osteotomy (ASO) with and without Le Fort I surgery., Materials and Method: This retrospective study included 32 adults with bimaxillary protrusion who underwent ASO alone (group 1) or with concomitant Le Fort I osteotomy (group 2). Subject's computed tomography scans at basic (T0), immediate postoperatively (T1), and at 1 year or more follow-up (T2) were collected. The condyle displacement was measured at superior-inferior, lateromedially, and anteroposterior surfaces, while condyle remodeling was measured at the superior, lateral, anterior, medial, and posterior surfaces. All 3D analyses were performed using 3D Slicer software (4.11.2)., Results: At T1, 52.7%, 86.7%, and 94.4% of condyles in group 1 were displaced inferiorly, laterally, and posteriorly, respectively, as well as 75%, 89.2%, and 53.5% of condyles in group 2, which had not fully returned to the original preoperative positions at T2. Condylar remodeling was observed in both groups at T2, and no significant difference was found in the overall condylar volume between T1 and T2 in both groups. Patients in group 2 exhibited significant bone resorption at both lateral and anterior surfaces compared to group 1 (P = 0.000 and 0.01, respectively)., Conclusion: This study's results demonstrated that ASO is associated with a degree of condylar changes even if the posterior mandible is not osteomized. The positional changes vary between bimaxillary ASO alone and those with simultaneous Le Fort I osteotomy. However, both groups' condyle volume remained stable at the long-term follow-up., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To establish a three-dimensional method to evaluate whether there is a difference in stability between bimaxillary simultaneous genioplasty and simple genioplasty., Methods: This study was a retrospective study. Sixty patients who underwent genioplasty were selected. They were divided into bimaxillary simultaneous genioplasty group (n=30) and simple genioplasty group (n=30). The spiral CT data of patients at 2 months before operation (T0), 7 days after operation (T1) and 12 months after operation (T2) were collected, reconstructed and separated, and the three-dimensional model of maxilla and mandible was obtained. A three-dimensional analysis method of stability was established by 3D-matching. Recurrences in three-dimensional space 12 months after surgery were analyzed in two groups of patients. Statistical analysis of the data was performed with SPSS 26.0 software package., Results: In simple genioplasty, the maximum amount of the chin recurrence was sagittal backward recurrence (0.54±0.38) mm, and the sagittal recurrence rate was 12.27%. In bimaxillary simultaneous genioplasty, the maximum amount of the chin recurrence was sagittal backward recurrence (0.60±0.31) mm, and the sagittal recurrence rate was 12.96%. Rotation occurred in both groups 12 months after operation, which was 1.98±2.70° in the simple genioplasty group and 1.01±1.61° in the bimaxillary simultaneous genioplasty group(P＜0.05). There was no significant difference in the sagittal movement of the chin between the two groups, and in the sagittal recurrence(P＞0.05)., Conclusions: The three-dimensional method established in this study can be used to evaluate the stability after genioplasty. The recurrence after genioplasty mainly occurred in the sagittal direction. The rotation trend of chin after genioplasty is worthy of attention. There was no increased risk for bimaxillary simultaneous genioplasty.

Purpose: To measure and compare changes in postoperative condylar position following bilateral sagittal split osteotomy in patients with asymmetry treated using a posterior bending osteotomy (PBO) and conventional methods (shaving of premature contacts)., Methods: Participants were randomized to either the PBO or conventional group. The inclusion criteria were the need for bilateral sagittal split osteotomy or bimaxillary asymmetric surgery (menton deviation >4 mm). The primary outcome variable was changes in the condylar position in the axial, coronal, and sagittal planes 6 months after surgery, whereas the secondary outcome variable was changes in temporomandibular joint symptoms. Covariates included surgery type, deformity type, age, and sex. Categorical and numerical variables were analyzed using Fisher exact χ 2 test and 2-way analysis of covariance., Results: The study sample comprised 42 patients with a mean age of 23.3 years; 57.5% were women. The alteration in the coronal condyle angle was 0.8⁰ ± 0.86⁰ in the PBO and 2.72⁰ ± 0.81⁰ in the conventional group. The differences in the condylar position in the coronal plane were not statistically significant (P = .129). The alteration in the axial condyle angle was 2.31⁰ ± 1.74⁰ in the PBO group and 5.65⁰ ± 1.65⁰ in the conventional group. The alteration in the sagittal plane was 0.44⁰ ± 1.52⁰ in PBO and 0.47⁰ ± 1.44⁰ in the conventional group. Alterations in axial (P = .194) and sagittal (P = .976) condylar positions were insignificant. In the conventional group, statistically significant differences were found in the axial (P = .002) and coronal (P = .002) planes, and the condyle turned inward in both planes. There were no statistically significant differences between the groups or within the groups in the sagittal plane (P > 0,5). In PBO and conventional groups, joint noise examination revealed positive results in 11 and 6 patients preoperatively and 1 and 2 patients postoperatively, respectively. A statistically significant decrease in joint noise was detected in the PBO group (P = 0,04). The maximum mouth opening without pain was 5.95 ± 1.47 in the PBO group and 7.91 ± 1.39 in the conventional group, respectively. The alteration was not statistically significant between the groups but was significant within the groups (P < .001)., Conclusions: PBO effectively prevents premature contact between mandibular segments in facial asymmetry., (Copyright © 2023 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Objective: The present study aimed to characterize three-dimensional (3D) long-term quantitative condyle change including positional, surface, and volumetric alterations in patients with skeletal class III malocclusion treated with bimaxillary orthognathic surgery., Material and Methods: Twenty-three eligible patients (9 males, 14 females, mean age: 28.28 years old) treated from Jan. 2013 to Dec. 2016 with postoperative follow-up over 5 years were retrospectively enrolled. Cone-beam computed tomography scan for each patient was conducted at 4 stages: 1 week preoperatively (T0), immediately after surgery (T1), 12 months postoperatively (T2), and 5-year postoperatively (T3). Positional changes, surface, and volumetric remodeling of condyle were measured in segmented visual 3D models and statistically compared between stages., Results: Our 3D quantitative calibrations revealed that the condylar center shifted in anterior (0.23 ± 1.50 mm), medial (0.34 ± 0.99), and superior (1.11 ± 1.10 mm) directions and rotated outward (1.58 ± 3.11°), superior (1.83 ± 5.08°), and backward (4.79 ± 13.75°) from T1 to T3. With regard to condylar surface remodeling, bone formation was frequently observed in the anteromedial areas, while bone resorption was commonly detected in the anterolateral area. Moreover, condylar volume remained largely stable with a minimal reduction during the follow-up., Conclusion: Collectively, although condyle undergoes positional changes and bone remodeling after bimaxillary surgery in patients with mandibular prognathism, these changes largely fall in the range of physical adaptations in the long run., Clinical Relevance: These findings advance the current understanding of long-term condylar remodeling after bimaxillary orthognathic surgery in skeletal class III patients., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: This study aimed to determine the positional changes in the condyle in the temporomandibular joint (TMJ) of severe skeletal class II malocclusion patients treated with surgical-orthodontics., Materials and Methods: The measurements of TMJ space in 97 severe skeletal class II malocclusion patients (20 males, 77 females, mean age, 24.8 years, mean ANB = 7.41°) were assessed using limited cone-beam computed tomography (LCBCT) images acquired before orthodontics (T0) and 12 months after surgery (T1). 3D remodeling of the TMJ and measurements of the anterior space (AS), superior space (SS), and posterior space (PS) were performed to determine the position of the condyle for each joint. All data were analyzed by t test, correlation analysis, and Pearson correlation coefficient., Results: The mean AS, SS, and PS values after the therapy changed from 1.684 to 1.680 mm (0.24%), 3.086 to 2.748 mm (10.968%), and 2.873 to 2.155 mm (24.985%), respectively. The decreases in SS and PS were statistically significant. Positive correlations were found in the mean AS, SS, and PS values between the right and left sides., Conclusions: The combination of orthodontic and surgical treatment makes the condyle move counterclockwise in the TMJ in severe skeletal class II patients., Clinical Relevance: Studies of temporomandibular joint (TMJ) intervals changes in patients with severe skeletal class II after sagittal split ramus osteotomy (SSRO) are limited. The postoperative joint remodeling, resorption, and related complications remain unstudied., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To retrospectively compare the high-angled sagittal split osteotomy (HOO) and the bilateral sagittal split osteotomy (BSSO) for the correction of skeletal dysgnathias regarding intra- and postoperative complications., Methods: The electronic medical records of all patients treated with an orthognathic surgery at the Department for Oral, Maxillofacial and Facial Plastic Surgery, University Hospital Frankfurt, Germany, between the years 2009 and 2019 were retrospectively reviewed., Results: Two hundred ninety-one patients were included. The overall complication rates were 19.78% (BSSO) compared to 12.5% (HOO) (p = 0.14). Significant differences were found regarding the operation time (HOO < BSSO, p = 0.02), material failure (HOO > BSSO, p = 0.04), and early recurrence requiring revision surgery (HOO < BSSO, p = 0.002). The use of a ramus plate significantly reduced the risk of plate failure (2.8% < 13.6%, p = 0.05). More bad splits (p = 0.08) and early sensory disorders (p = 0.07) occurred in the BSSO group., Conclusion: The HOO presents a possible alternative to the BSSO since newly developed osteosynthesis material significantly reduces the risk of material failure. The BSSO is accompanied by higher risks of developing complications like a bad split and sensory disorders but, however, remains the standard for large anterior-posterior transpositions of the mandible., (© 2022. The Author(s).)

Tensionless adaptation of nerve ends is a challenging task in the repair of damaged inferior alveolar nerve (IAN). A new technique is introduced with posterior ostectomy of a mandibular distal segment after sagittal splitting for nerve bundle traction to tensionless anastomosis of nerve ends. We were able to create tensionless anastomosis of an IAN defect without autogenous or alloplastic graft using this method. This method is suitable for neurorrhaphy after neuroma removal in cases of IAN damage during dental procedures., Competing Interests: Declaration of Competing Interest None., (Copyright © 2022 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Purpose: Patients with facial asymmetry often seek improved symmetry in lower face contour resulting in transverse movement of the proximal segments. The study aimed to investigate the association between transverse change in the proximal segments and postoperative relapse after the surgical correction of skeletal Class III facial asymmetry., Methods: This retrospective cohort study includes consecutive patients with skeletal Class III asymmetry who underwent 2-jaw orthognathic surgery. The primary predictor variable was ramus plane angle (RPA). The patients were grouped as small (S group, <4°) and large (L group, ≥4°) changes in RPA. The primary outcome was the positional change of B point, menton, and the intergonial width. Cone-beam computed tomography images were obtained before surgery (T0), 1 week after surgery (T1), and debond (T2). Intergroup comparison was conducted with independent t test. Correlations between the variables were estimated by Pearson correlation., Results: The study sample was composed of 60 subjects with 30 subjects in each study group. In the S group, the mean surgical changes of RPA were inward rotated 0.91° bilaterally. In the L group, the mean surgical changes of RPA were inward rotated 4.80° and 0.32° on the deviated and non-deviated side. After surgery, further minor inward adaptation of both sides was noted (<1 mm), and intergonial distance reduced with these changes in the proximal segments. By comparing the postsurgical stability between S and L group, the overall sagittal and vertical stability had no significant difference between 2 groups. However, the postsurgical transverse menton relapse (ΔMe in T2-T1) was significantly larger in L group (0.81 ± 1.40 mm) than S group (0.04 ± 1.32 mm) by 0.77 mm (P = .014)., Conclusion: Greater surgical changes in the proximal segments had minor clinical effect on transverse stability. Minor transverse overcorrection of 1 mm is recommended in cases with severe facial symmetry with extensive changes in the proximal segments., (Copyright © 2023 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Condylar displacement and remodelling are phenomena closely related to orthognathic surgery and critically involved in occlusal and skeletal stability. The aim of the present case report is to describe over time condylar displacement and surface remodelling after bilateral split sagittal osteotomy (BSSO) in an adult patient with severe class II skeletal malocclusion treated with ortho-surgical approach. A male of 21years comes to our observation. The extraoral examination shows a symmetrical square-shaped face, a convex profile, an acute nasolabial angle and a deep labiomental fold. Intraoral examination reveals a class II division 2 with a 2mm deviation of the mandibular midline to the left and the presence of a scissor bite of the bicuspids between quadrants II and III. The Spee curve and overbite are extremely accentuated (OV 14.3mm) as the overjet (11.1mm). Axiographic reconstructions of CBCT show a normal shape and position of both condyles. The cephalometric analysis shows a reduced lower facial height, a normal upper jaw position, a mandibular underdevelopment masked by a very developed symphysis and an extremely low divergence (FMA 11.2°). BSSO for mandibular setback was performed in the 13th month of orthodontic therapy. Original CBCT data before surgery (T0), at the end of treatment (T1), 2years postoperatively (T2) and 5years postoperatively (T3) were collected and reconstructed for 3-dimensional (3D) qualitative analyse. At the end of the surgical-orthodontic treatment (26months), good function and good aesthetics were achieved. The qualitative and comparative analysis of the superimpositions and the cuts made on the CBCT at T0, T1, T2, T3 showed a physiological remodelling and adaptation of the condyles., (Copyright © 2023 CEO. Published by Elsevier Masson SAS. All rights reserved.)

Background: To model the effect of isolated bilateral sagittal split osteotomy (BSSO) on changes in posterior (PSD), superior (SSD), and medial space dimensions (MSD) of the temporomandibular joint., Methods: Using a retrospective cohort study design, pre- and postoperative (immediately after surgery; 1 year follow-up) cone-beam computed tomography measurements of 36 patients who had undergone BSSO for mandibular advancement were compared with a control group of 25 subjects from whom a mandibular odontogenic cyst was removed under general anesthesia. Generalized estimation equation (GEE) models were used to examine the independent effects of study group, preoperative condylar position, and time points on PSD, SSD, and MSD adjusting for covariates (age, sex, and mandibular advancement)., Results: No significant differences were found regarding changes in PSD (p = 0.144), SSD (p = 0.607), or MSD (p = 0.565) between the BSSO and control groups. However, the preoperative posterior condylar position showed significant effects on PSD (p < 0.001) and MSD (p = 0.043), while the preoperative central condylar position demonstrated a significant effect on PSD (p < 0.001)., Conclusion: The data suggest that preoperative posterior condylar position is a significant effect modifier of PSD and MSD over time in this cohort., (© 2023. The Author(s).)

Bilateral sagittal split osteotomy (BSSO) mandibular advancement can cause mandibular lower border notching (MLBN). The objective of this study was to calculate the incidence of MLBN and identify risk factors. This single-centre, retrospective study was performed between January 2018 and November 2020, in the Maxillofacial Surgery Department, Centre Hospitalier Universitaire, Caen. Patients who underwent BSSO advancement and had cone beam computed tomography (CBCT) scans obtained preoperatively, immediately postoperative (within 1 week), and late postoperative (≥1 year) were included. Measurements were made on the CBCT images. A total of 113 patients (226 operated sides) were enrolled. Mean age at the time of surgery was 17 years; 66.4% of patients were female and 33.6% were male. MLBN was observed on 35 operated sides (15.5% of sides). Advanced age (P = 0.002) and the degree of mandibular advancement (P = 0.008) were determined to be risk factors for developing MLBN. Sex, the operated side, third molar removal, and genioplasty were not associated with an increased occurrence of MLBN. Older patient age at the time of surgery and the requirement for a large advancement should be taken into consideration by the surgeon in order to reduce the risk of MLBN by using a modified BSSO procedure or bone grafting., (Copyright © 2022. Published by Elsevier Inc.)

Bilateral sagittal split osteotomy for orthognathic surgery is the most used technique for mandible advancement or setback and has been well documented and modified over the years since Trauner and Obwegeser described it. The improvement brought by each technique allowed the surgeons to perform safer osteotomies, shorten the operative time, and increased the flexibility of the programmed mandibular movements. The authors present a modification of the bilateral sagittal osteotomy technique with the aim of making the technique easier to perform and more comfortable for the surgeon for the purpose of positioning the osteosynthesis plates and screws. Finally, the authors describe a nomenclature on the osteotomy lines of the bilateral sagittal split osteotomy., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 by Mutaz B. Habal, MD.)

Purpose: Despite decades of study, the best technique for mandibular ramus sagittal osteotomy has not been definitively determined. The purpose of the present study was to compare fracture patterns, inferior alveolar nerve (IAN) visualization, and torque required for mandibular sagittal splitting using the Hunsuck/Epker, Wolford, and Posnick techniques., Methods: This was a laboratory (ex vivo), randomized, a single-blind study performed to evaluate sagittal split osteotomies in porcine mandibles using a specifically designed test system. The study's predictor variable was the osteotomy technique, which was divided into 3 groups: Group Hunsuck/Epker (GHE), group Wolford (GW), and group Posnick (GP). The outcome variables were lingual fracture pattern, torque in newtons (N) required to separate the mandible, and IAN visualization. The covariates were mandibular radiodensity and time between dejection and the experiment. The Kolmogorov-Smirnov normality statistics and analysis of variance with Tukey post test statistics were performed. P value <.05 was considered statistically significant., Results: The sample was composed of 120 equally divided porcine hemimandibles in each group. The torque forces were significantly lower (P < .001) when using the Posnick technique (2.07 ± 0.22 N) than when using the Hunsuck/Epker technique (4.45 ± 0.32 N) and Wolford (3.00 ± 0.21 N). GW (93.3%) and GHE (56.7%) showed a higher prevalence of lingual fracture in the posterior region of the mandibular canal (P < .001), while the GP (90%) had a higher frequency of lingual fracture pattern on the mylohyoid sulcus (P < .001). In more than 90% (P < .001) of the mandibles in GW and GHE, the IAN visualization was higher than 50%. In the GP, 90% (P < .001) of patients had IAN visualization of less than 50%., Conclusions: The Posnick technique required less torque to perform the sagittal osteotomy in a pig mandible and had good predictability (90%) for the less preferred lingual fracture pattern and minimal visualization of the nerve. The Wolford technique provided the best predictability (93%) for the preferred lingual fracture pattern and the best nerve visualization. Caution must be exercised when extrapolating the results from animal models to human applications., (Copyright © 2023 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Objective: To investigate and compare the effect of two orthognathic procedures for mandibular setback, namely, sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO), on oral health, mental- and physical health-related quality of life across time., Materials and Methods: Patients with mandibular prognathism and planned for orthognathic surgery were recruited in this study. Patients were randomized into two groups (IVRO and SSRO groups). Quality of life (QoL) was assessed with the 14-item Short-Form Oral Health Impact Profile (OHIP-14) and the 36-item Short-Form Health Survey (SF-36) preoperatively (T 0 ), postoperative 2 weeks (T 1 ), 6 weeks (T 2 ), 3 months (T 3 ), 6 months (T 4 ), 12 months (T 5 ), and 24 months (T 6 ). A comparison of OHIP-14 and SF-36 scores between two groups was conducted., Results: Ninety-eight patients (49 SSRO group, 49 IVRO group) participated in this study. There was no significant difference in OHIP-14 scores between SSRO and IVRO throughout the treatment process. SSRO group had significant reduction of OHIP-14 score (i.e., improving oral health-related QoL) since postoperative 2 weeks, whereas IVRO group had significant reduction since postoperative 6 weeks. Starting from postoperative 3 months, the oral health-related QoL of both groups was already significantly better than the baseline level and continued to steadily improve afterwards. For SF-36, both groups had increased physical health summary score starting from postoperative 2 weeks, indicating an early and gradual recovery of physical health-related QoL. The mental health summary score of the SSRO group began to increase from postoperative 2 weeks, but that of the IVRO group only began to increase from postoperative 6 weeks. Patient age at the time of surgery was positively correlated with OHIP scores in the postoperative period., Conclusions: The study concludes that both SSRO and IVRO contributed to the improvement of QoL in the long term, but oral health- and mental health-related QoL of SSRO groups showed earlier improvement., Clinical Relevance: Undergoing orthognathic surgery at early ages is advised, as older age of patients appeared to have worse QoL., Trial Registration: Clinical trial registration number: HKUCTR-1985. Date of Registration: 14 Apr 2015., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The sagittal split ramus osteotomy (SSRO) has been performed mainly on an inpatient basis because of the duration of anaesthesia and the potential risk of postoperative complications, such as bleeding, pain, nausea, and vomiting. However, advances in both surgical and anaesthetic management have enabled the reduction of these risks and shortened the length of hospital stay. Thus, the SSRO may be feasible even in the ambulatory setting in elective cases. The clinical records of all patients who underwent an outpatient SSRO between August 2011 and September 2020 at Lilla Craniofacial Clinic were reviewed retrospectively. Data on age, sex, duration of surgery, operative procedures, intraoperative bleeding, and admission status were investigated. In total, 143 patients underwent a bilateral SSRO. The SSRO was performed as an isolated procedure in 73 patients and concomitantly with other surgical procedures in the remaining 70 patients. Overall, 142 of the 143 patients were discharged on the day of surgery (99.3%); only one (0.7%) required an overnight stay because of a submental haemorrhage after genioplasty. No emergency hospitalizations or readmissions occurred after discharge. Multimodal perioperative management, both surgical and anaesthetic, facilitated enhanced patient recovery after surgery, and SSRO was performed successfully and safely as an ambulatory procedure., (Copyright © 2022 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Objectives: This study aimed to find out the correlation between different anatomical parameters of the mandible and the occurrence of a bad split in patients who had undergone bilateral split sagittal ramus osteotomy (BSSRO)., Materials and Method: At both the distal roots of the first molar (1) and the retromolar area (2), we measured the distance from the buccal margin of the inferior dental canal (IDC) to the buccal margin of the cortical bone (MCBC), the thickness of both buccal cortical (WBCB) and cancellous bone (WBCA), distance from the superior border of IDC to the alveolar crest (MCAC), buccolingual thickness (BLT), and thickness of cancellous bone (WCA). At the ramus, the distances between the sigmoid notch to the upper part of the lingula (SL) and the inferior border of the mandible (SIBM), the thickness of the ramus at the level of the lingula (BLTR), and the anteroposterior width of the ramus (APWR) were measured. The paired and independent t-tests were used when applicable, and a P-value < 0.05 was considered significant., Results: MCBC1 showed a significant difference between bad and non-bad split sides (P = 0.037). Both WBCA1 and WBCA2 show the same significant difference (P = 0.023, 0.024). Similarly, WCA1 and WCA2 showed a statistical difference between the bad and non-bad split sides (P = 0.027, 0.036). There were no statistically significant differences between the compared sides of WBCB1, WBCB2, MCAC1, MCAC2, SIBM, APWR, SL, and BLTR., Conclusion: Narrow space between IDC and the buccal cortical margin, along with the decrease in the thickness of both buccal cancellous bone and total cancellous bone at the inferior border of the mandible along the course of SSRO, has been implicated in the occurrence of bad split intraoperatively., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: A recently proposed modification of the sagittal split osteotomy (SSO) of the mandible places the horizontal medial cut 'low and short' of the lingula. The purpose of the study was to answer the following clinical question: Among patients undergoing mandibular setback procedures (≤ 8 mm) via SSO, does the placement of the medial horizontal osteotomy below the lingula (infralingular), when compared to placement above the lingula (supralingular), results in different neurosensory, bite force, and range of motion outcomes?, Materials and Methods: This was a single-center, double-blind, parallel-group study among patients undergoing mandibular setback by SSO (≤ 8 mm), between January 2021 and September 2022. Patients were randomly allocated in a ratio of 1:1 to the supralingular (control) and the infralingular (study) group. Primary outcome variables included neurosensory disturbance of the inferior alveolar nerve based on clinical neurosensory testing and severity graded using Zuniga and Essick's protocol, bite force, and maximum mouth opening evaluated postoperatively during the first week (T1), first month (T2), and third month (T3) of follow-up. Secondary outcome measures included the incidence of a bad split and distal segment interferences intraoperatively. Association between the variables was assessed using Pearson chi-squared test or Fisher's exact test based on the expected observations. A P value of ≤.05 was considered statistically significant., Results: A total of 29 patients (58 osteotomies) were included in the study. Group 1 consisted of 15 patients (9 females and 6 males) with a mean age of 26.4 years. Group 2 consisted of 14 patients (8 females and 6 males) with a mean age of 25.9 years. Patients with severe neurosensory disturbance of the inferior alveolar nerve were more common in group 2 (n = 15, 53.6%) than group 1 (n = 4, 13.3%) at T1 (P value = .0001) and insignificant between the two groups at T2 (P value = .63) and T3 (P value = .99). Comparison of maximum mouth opening between the two groups at T1 (P value = .535), T2 (P value = .934), and T3 (P value = .703) and bite force at T1 (P = .324), T2 (P = .113), and T3 (P = .811) was not significant., Conclusion: Both SSO techniques have similar clinical outcomes among patients having mandibular setbacks (≤ 8 mm) for the variables studied., (Copyright © 2022 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

The aim of the study was to describe an approach where condylar resection with condylar neck preservation was combined with Le Fort I osteotomy and unilateral mandibular sagittal split ramus osteotomy (SSRO). Patients with a unilateral condylar osteochondroma combined with dentofacial deformity and facial asymmetry who underwent surgery between January 2020 and December 2020 were enrolled. The operation included condylar resection, Le Fort I osteotomy and contralateral mandibular sagittal split ramus osteotomy (SSRO). Simplant Pro 11.04 software was used to reconstruct and measure the preoperative and postoperative craniomaxillofacial CT images. The deviation and rotation of the mandible, change in the occlusal plane, position of the "new condyle" and facial symmetry were compared and evaluated during follow-up. Three patients were included in the present study. The patients were followed up for 9.6 months on average (range, 8-12). Immediate postoperative CT images showed that the mandible deviation and rotation and occlusion plane canting decreased significantly postoperatively; facial symmetry was improved but still compromised. During the follow-up, the mandible gradually rotated to the affected side, the position of the "new condyle" moved further inside toward the fossa, and both the mandible rotation and facial symmetry were more significantly improved. Within the limitations of the study it seems that for some patients a combination of condylectomy with condylar neck preservation and unilateral mandibular SSRO can be effective in achieving facial symmetry., Competing Interests: Declaration of competing interest The authors have no conflicts of interest to declare., (Copyright © 2023 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

The aim of this systematic review and meta-analysis was to assess whether the presence of inferior third molars during sagittal split mandibular ramus osteotomy increases the risk of intraoperative and postoperative complications. The PRISMA protocol was followed in this study, and the review was registered in the PROSPERO database (CRD42020147642). A search was conducted in the MEDLINE (PubMed), Web of Science, Cochrane Central, and Scopus databases on November 1, 2021. Nineteen articles were included, and the variables analysed were unfavourable fractures, infection, neurosensory disturbance, removal of osteosynthesis material, and duration of surgery. Meta-analyses were performed for the variables unfavourable fractures (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.58-1.57, P = 0.84), infection (RR 0.75, 95% CI 0.48-1.18, P = 0.21), and neurosensory disturbance (RR 1.55, 95% CI 0.61-3.91, P = 0.35); no statistically significant difference in the risk of these variables was found between the groups with and without third molars. The third molars did not increase the need to remove fixation material, but increased the surgery time. The presence of the third molar during sagittal split mandibular ramus osteotomy appears not to increase the risk of intraoperative and postoperative complications. The results presented here must be interpreted with caution due to the heterogeneity presented by the observational studies included., (Copyright © 2022 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

An unfavourable split is a well-known complication following a sagittal split osteotomy (SSO) of the mandible. Our aim was to analyse all unfavourable mandibular splits that had occurred when carrying out a SSO with the aim to design a classification which can facilitate management. We carried out a retrospective study analysing all orthognathic surgery from January 2010 until April 2021. Data surrounding unfavourable splits during this period were specifically analysed. Orthognathic surgery during this period was performed by a single OMFS unit with osteotomies performed by a single surgeon and their trainee. The dataset included 311 patients who underwent either a bilateral sagittal split osteotomy (BSSO) or a bimaxillary osteotomy. There were 225 bimaxillary osteotomies and 86 BSSOs. Twenty-one patients had unfavourable splits following their BSSO with a total of 22 out of 622 sagittal split osteotomies over this 11-year period. Bilateral unfavourable splits occurred in one patient. These results correlate to an incidence rate of 6.8% of unfavourable splits following SSO's in an 11-year period. The results reveal common patterns of unfavourable splits to suggest a simple classification based on our results. This can be applied to any unfavourable splits in SSO which then allows the clinician to proceed with surgery and prevent abandonment of the procedure. It is classified as follows: Type 1 fractures where the mandibular condyle is attached to the proximal fragment; Type 2 fractures whereby the mandibular condyle is attached to the tooth-bearing segment; Type 3 fractures are lingual cortex fractures. Each of these fracture types has a specific management protocol, which we recommend is used in all unfavourable splits., (Copyright © 2022 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

This study was performed to evaluate the condylar displacement and associated condylar remodeling in class III patients following mandibular setback surgery via sagittal split ramus osteotomy (SSRO). The sample comprised of 26 condyles of 13 subjects (mean age of 21.2±2.6 y). We evaluated patients with mandibular prognathism and facial asymmetry who had undergone SSRO for mandibular setback at Korea University Hospital between January 2016 and December 2018. Three-dimensional segmentation of the mandibular condyles was done using the initial cone-beam computed tomography scan and scan taken 12 months postoperatively or later. Quantitative assessments of the 3-dimensional condylar displacement from T0 to T1 and bony remodeling of 8 regions of the condylar head were performed. The correlation between the condylar displacement and condylar head remodeling on the deviated (D) and nondeviated (ND) sides was analyzed. Significant correlations between condylar displacement and surface remodeling were observed in both D and ND condyles. The anteroposterior condylar displacement was significantly different between the D and ND sides (P=0.007). There was no significant difference in condylar remodeling between the 2 sides. Condylar displacement and adaptive remodeling after SSRO varied greatly among individuals. Compared with displacement in the ND condyle, displacement in the D condyle has a greater association with condylar remodeling in both D and ND condyles. There is no significant difference in condylar head remodeling between D and ND condyles., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of Mutaz B. Habal, MD.)

Purpose: This study compared the mechanical behavior of two fixation techniques used in three sections representing the sagittal split ramus osteotomy (SSRO) in polyurethane replicas that were divided into groups, according to type of section, and sub-groups according to type of fixation, simulating 11-mm advancement and 6º clockwise mandibular rotation., Methods: Loads were applied in two regions, aiming at progressive application and consequent strength value, measured in kilogram-force in displacements of 1, 3, 5, and 7 mm, from the load application tip. Shapiro-Wilk test was performed, followed by two-way analysis of variance (ANOVA-2 way), and Bonferroni's multiple comparison., Results: The results showed no statistically significant difference in the type of section and type of fixation used when load was applied to the inter-incisor region. However, when load was applied to the first molar region, statistically significant difference was observed in 1-mm displacement, in which section described by Epker with two modifications showed greater strength, regardless of type of fixation used (p = 0.007)., Conclusion: In the application of load in the inter-incisor region, there was no statistical difference between the type of osteotomy and the type of fixation used. When applying loads to molars, there was a difference for the type of osteotomy, where the Epker osteotomy with 2 modifications presented greater resistance, regardless of the type of fixation used., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The aim of the study was to assess the changes in the condylar position after orthognathic surgery (OGS) and its effect on temporomandibular disorders (TMD). A total of 37 dentofacial deformity patients included in the study who had undergone OGS were divided into three groups: Group I, Le Fort I maxillary advancement; Group II, bilateral sagittal split osteotomy (BSSO) mandibular advancement ± Le Fort I; and Group III, BSSO mandibular setback ± Le Fort I. Patients were evaluated clinically using Diagnostic Criteria for TMD and by radiography preoperatively and 6 months postoperatively. The positional changes in condyle were correlated with signs and symptoms of TMD. A total of 37 patients in three groups (Group I, 8 patients; Group II, 10 patients; and Group III, 19 patients) were evaluated. Overall, condyles had anterio-medio-inferior movement with 7 of 8 patients in Group I, 6 of 10 patients in Group II and 13 of 19 patients in Group III having ≤2 mm displacement. In angular changes, inward-anterio-medial movement was observed with 6 of 8 patients in Group I; about 5 of 10 patients, and 10 of 19 patients in Group II and III respectively had ≤5° change. Intragroup and intergroup comparisons showed insignificant changes in TMD and linear/angular movement (p ≥ 0.05). Pearson correlation coefficient was found to be nonsignificant on the radiographic and clinical comparison (p ≥ 0.05). Intrarater reliability (Kappa value) was found to be 0.83, confirming the results. Within the limitations of the study it seems that there are minimal linear and angular changes in condyle after orthognathic surgery that were not responsible for the development of temporomandibular disorders in the postoperative course., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

Objectives: To evaluate postoperative mandibular stability and condylar changes in patients with mandibular hypoplasia and preoperative condylar resorption (CR) undergoing orthognathic surgery., Materials and Methods: Fifty-four patients were included in this retrospective study. Computed tomography (CT) scans were acquired preoperatively (T0), 2-7 days immediate postoperatively (T1), and at least 1 year postoperatively (T2). Three-dimensional (3D) cephalometric analysis and measurements of condylar angle, volume, and position (joint spaces) were performed. A 2-mm mandibular relapse was deemed clinically acceptable. We also analyzed the correlations between relapse and postoperative CR and susceptible factors using a multivariate logistic regression model., Results: The results showed one year after the surgery, the average mandibular relapse was 1.0 mm (p < 0.05), and the average reduction of condylar volume was 152.4 mm 3 (12.7%). Condyle-fossa relationships were improved immediately after the surgery, with a tendency of returning to their original state in the follow-up (p < 0.05). Anteroposterior advancement at point B (B-CP advancement) at T1 and superior joint space (SJS) at T0 were significantly correlated with mandibular relapse, and postoperative CR was mainly associated with vertical increasement at point B (B-AP increasement) at T1. The optimal cut-off values were as follows: 1.6 mm for SJS, 4.2 mm for B-CP advancement, and 1.8 mm for B-AP increasement. Concomitant advancement Genioplasty showed no significant correlation with relapse and postoperative CR., Conclusions: While patients with mandibular hypoplasia and preoperative CR were vulnerable to further condylar resorption after mandibular advancement, the treatment outcomes were generally clinically acceptable. Postoperative relapse was associated with a larger than 4.2 mm of mandibular advancement measured at B-CP and a larger than 1.6 mm of superior joint space measured at SJS, and postoperative CR was associated with a larger than 1.8 mm of mandibular vertical increasement measured at B-AP., Clinical Relevance: The findings of this study suggested that the mandibular advancement might be limited to 5 mm for patients with preoperative CR. A concomitant advancement genioplasty might also be considered to achieve a better facial profile in these patients., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Levasseur-Merrill retractor (LMR) utilization during the intraoral vertical ramus osteotomy (IVRO) helps initiate the osteotomy approximately 7 mm from the posterior border of the mandible, preventing damage to the inferior alveolar nerve. The purpose of this in vivo study is to evaluate the IVRO placement and the risk of neurosensory deficit (NSD) while using the LMR., Methods: This prospective case series was conducted at a single tertiary care center. Medical records were reviewed for medical and demographic information. Inclusion criteria were as follows: underwent the IVRO procedure by a single provider from June 2020 to June 2022 and postoperative cone beam computed tomography images. Exclusion criteria were as follows: age less than 16 years, previous mandibular osteotomies, inadequate clinical documentation, or follow-up. The primary outcome variables included the proximal segment width and proximity of the IVRO to the inferior alveolar foramen. The secondary outcome variable was NSD as measured subjectively by 2-point discrimination, sharp versus dull touch, and light touch with von Frey filaments., Results: The 26 subjects (42 operated sides) were 96% female, with an average age of 30.1 years (range 17-54 years). The mean proximal segment width was 10.3 ± 1.7 mm (95% confidence interval: 9.77, 10.83). The mean distance from the posterior border of the inferior alveolar foramen (IAF) to the osteotomy was -0.89 ± 1.7 mm (95% confidence interval: -1.43, -0.35), with negative numbers indicating violation of the IAF. IAF and full bony canal violation occurred in 61.9% and 4.8% of operated sides, respectively. NSD at 6 months postoperatively occurred in the 2 sides that experienced full bony canal violation., Conclusions: The LMR did not consistently guide the IVRO position within 7 mm from the posterior border of the mandible as previously thought and allows for frequent violation of the IAF. Long-term NSD of the inferior alveolar nerve was infrequent and correlated with violation of the full bony canal., (Copyright © 2022. Published by Elsevier Inc.)

The aim of this study was to evaluate the stress distribution and displacement values of six different miniplate systems in large mandibular advancement after sagittal split ramus osteotomy (SSRO) with finite element analysis (FEA). A three-dimensional model of a mandible was created and a 10 mm advancement SSRO was simulated. The model was fixed using a four-hole miniplate, a six-hole miniplate, a newly designed six-hole miniplate and their curved versions. Maximum principal stress values for bone, von Mises stress values for osteosynthesis materials, and the amount of displacement between segments were measured. The highest von Mises value was observed in the curved version of the newly designed six-hole miniplate; the lowest value was detected in the four-hole curved miniplate. The lowest value of maximum principal stress in the bone was found in the curved version of the novel design six-hole miniplate. The least displacements between segments were also recorded in the new design of straight miniplate; therefore, for large mandibular advancement surgery, this novel six-hole miniplate may be a promising option with positive biomechanical characteristics., Competing Interests: Conflict of interest We have no conflict of interests., (Copyright © 2022 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

The aim of this study was to compare how the displacement of the mandibular condyle changed after symmetric or asymmetric mandibular setback surgery using the surgery-first approach (SFA). Patients who underwent mandibular setback surgery using the SFA were selected and divided into a symmetry group (n = 18) with differences of less than 2 mm between the right and left setback, and an asymmetry group (n = 18) with a difference of greater than 2 mm. Cone-beam computed tomography (CBCT)-generated cephalograms were obtained after three-dimensional superimposition of CBCT images taken before surgery (T0), within one week after surgery (T1), and seven months after surgery (T2). The condylar positions were measured. Condylar positional changes according to time were compared between the two groups and correlation analysis was performed. There were significant positional changes in mandibular condyles over time in both groups. However, most of these changes returned to their initial state. In the asymmetry group, there was a greater internal rotation of the mandibular condyle on the lesser setback side. The correlation analysis results revealed that only the setback difference was associated with rotational displacement of the condyle on the lesser setback side at two time points (T1-T0, T2-T0). In the SFA, significant condylar displacement occurred immediately after both symmetric and asymmetric mandibular setback surgery, and the right/left difference in mandibular setback showed a significant positive correlation with rotational displacement. Although more significant rotational displacement of the mandibular condyle was observed after asymmetric mandibular setback surgery, the amount was not large enough to be clinically significant., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

The aim of this study was to assess the occurrence of neurosensory disturbance of the inferior alveolar nerve (IAN) following modified mandibular bilateral sagittal split osteotomy (BSSO) that preserves the mandibular inferior border. All patients undergoing BSSO, associated or not with a Le Fort I osteotomy (performed by the same senior operator) between January 2018 and December 2019, were eligible. The modified BSSO consists of a modification of the technique described by Epker: the bony section of the buccal cortex stops 3-4 mm above the basal mandibular edge. While respecting the basilar border, sectioning is then performed up to the gonial angle where bicortical section is finally performed. Sensibility of the labial and chin area was evaluated immediately postoperatively, and at six months and two years of follow up. A total of 140 eligible patients underwent the modified BSSO between January 2018 and December 2019, and 72 were included. Hypoaesthesia was found in 81.9% of the patients (59/72 patients) at initial evaluation. It decreased to 45.8% (33/72 patients) at the six-month examination and to 12.5% (9/72 patients) at the last examination. Four bad splits were recorded. The modified BSSO preserves the inferior border of the mandible and maintains the IAN in the lingual fragment. There is no need to release the IAN, hence its manipulation is reduced and the incidence of IAN postoperative hypoaesthesia is also reduced., (Copyright © 2022 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Abstract: This study was performed to evaluate condylar position and angulation after asymmetric mandibular setback between a conventional (CA) and surgery-first approach (SFA) using three-dimensional analysis. The condylar positions of 30 patients with skeletal Class III malocclusion and facial asymmetry who underwent 1-jaw (sagittal split ramus osteotomy) or 2-jaw orthognathic surgery (Le Fort I osteotomy and sagittal split ramus osteotomy) with CA (n = 18) or SFA (n = 12) from 2 university hospitals were studied. The three-dimensional assessment of condylar changes was performed using computed tomography images at the initial time point (T0) and at least 6 months after surgery (T1). Segmentation of condyles and cranial base assessment from cone-beam computed tomography images were performed using ITK-SNAP software (version 3.4.0). Condylar position and angulation changes were calculated using 3D Slicer software (version 4.10.2), and statistical analysis was performed. No significant translational or rotational condylar changes were observed between the deviated and non-deviated sides in each group or between the CA and SFA groups except yaw ( p = 0.014). Linear mixed-model analysis and multi-variate analysis showed no significant difference between the CA and SFA groups. Surgery-first approach might not be associated with more harmful effects on the condylar position and angulation changes as compared with CA., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of Mutaz B. Habal, MD.)

The aim of this study was to clarify the effects of three different orthognathic surgical procedures on the temporomandibular joint after mandibular setback. Conventional sagittal split ramus osteotomy (SSRO) with segmental fixation (conv-SSRO), intraoral vertical ramus osteotomy (IVRO), or SSRO without fixation followed by the physiological positioning strategy (nonfix-SSRO) was performed for mandibular setback. Temporomandibular joint disorder (TMD) symptoms were clinically assessed, and the condylar head angle was measured. In total, 129 patients participated. Preoperative TMD and treatment procedure were related to postoperative TMD. A menton deviation of 3.43 mm was the cutoff for the risk of postoperative TMD. The incidence rate of postoperative TMD in the conv-SSRO group was higher than that in the IVRO (p = 0.0197) and nonfix-SSRO (p = 0.0001) groups in asymmetric cases. There was no significant postoperative change in the temporomandibular joint space in each group. In symmetric and asymmetric cases, the condylar head was rotated inwards by 5.82 ± 4.75° (p < 0.0001) and 5.44 ± 3.10° (p < 0.0001), respectively, in the conv-SSRO group, and outwards by -7.98 ± 5.05° (p < 0.0001) and -8.32 ± 6.38° (p < 0.0001), respectively, in the IVRO group, but it was almost stable in the nonfix-SSRO group. Within the limitations of the study it seems that nonfix-SSRO should be preferred over conv-SSRO and IVRO whenever appropriate., Competing Interests: Declaration of competing interest None to declare., (Copyright © 2022 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.)

The aim of this study was to investigate whether the bone marrow space volume of the mandible affects blood loss during bilateral sagittal split osteotomy (BSSO). Sixteen patients who underwent BSSO in our hospital were included in this study. Bone marrow space volume of the mandible was measured by analyzing images from computed tomography. Blood loss during BSSO was measured by weighing gauze, measuring suctioned blood, and adjusting for the volume of irrigation solution used during BSSO. Mean blood loss during BSSO for the 16 patients was 200.5 ml, and patients were divided into: Group I, with less than mean blood loss; and Group II, with greater than mean blood loss. Total bone marrow space volume was significantly greater in Group II (12,450.7 ± 2644.3 mm 3 ) than in Group I (9130.3 ± 3005.8 mm 3 ; P<0.05). A correlation between bone marrow space volume and blood loss during BSSO was suggested, and these results are beneficial for surgeons planning and preparing the orthognathic surgery., Competing Interests: Competing of Interests We declare that the authors have no conflicts of interest., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

The assessment of the stability of orthognathic surgery is often time-consuming, relies on manual re-identification of anatomical landmarks, and has been based on short-term follow-up. The purpose of this study was to propose and validate a semi-automated approach for three-dimensional (3D) assessment of the long-term stability of segmental bimaxillary surgery. The approach was developed and validated using cone beam computed tomography scans obtained at 2 weeks and 2 years postoperative. The stability of the surgical outcome was calculated as 3D translational and rotational differences between the short- and long-term postoperative positions of the individual bone segments. To evaluate reliability, intra-class correlation coefficients were calculated at a 95% confidence interval on measurements of two observers. Ten class II and III patients (six male, four female; mean age 24.4 years), who underwent a combined three-piece Le Fort I osteotomy, bilateral sagittal split osteotomy, and genioplasty, were included in the study. Intra- and inter-observer reliability were excellent (range 0.82-0.99). The range of the mean absolute difference of the intra- and inter-observer translational and rotational measurements were 0.14 mm (0.13)-0.44 mm (0.50) and 0.20° (0.16)-0.92° (0.78). The approach has excellent reliability for 3D assessment of long-term stability of segmental bimaxillary surgery., Competing Interests: Competing interests None., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

The purpose of this study is to evaluate mandibular osteotomy procedures during orthognathic surgery, with an emphasis on the complications of the two leading procedures: intraoral vertical ramus osteotomy (IVRO) and sagittal split osteotomy (SSO). We conducted a retrospective cohort study by extracting the records of patients who underwent either IVRO or SSO procedures during orthognathic surgery in a single center between January 2010 and December 2019. A total of 144 patients were included (median age of 20.5 years, 52 males). The IVRO:SSO ratio was 118:26 procedures. When referring to all surgeries performed, IVRO procedures were associated with shorter hospitalization than the SSO procedures, while the overall durations of surgery and follow-up periods were comparable. In contrast, when referring only to bimaxillary procedures, the duration of the IVRO bimaxillary procedures was significantly shorter than the SSO bimaxillary procedures. There were 53 complications altogether. Postoperative complications consisting of skeletal relapse, temporomandibular joint dysfunction, sensory impairment, and surgical-site infection were significantly fewer in the IVRO group. Both types of osteotomies have acceptable rates of complications. IVRO appears to be a safer, simpler, though less acceptable procedure in terms of patient compliance.

Abstract: Unfavorable fractures in sagittal split ramus osteotomy are hard to manage. The aim of this study is to develop a new classification method for unfavorable fractures of the proximal segment to guide clinical managements. After reviewing 964 cases of sagittal split ramus osteotomy, we found that the unfavorable fractures can be divided into 3 types: mandibular ramus transverse fractures (Type 1), bad fractures accompanied by free fragments (Type 2), and unexpected separation patterns without free fragments (Type 3). We calculated the incidence of each fracture type and provided instructions for their corresponding treatments. Thirty-six patients suffered from unfavorable fractures (7.4% of patients), among which 32 patients had unilateral fractures and 4 patients had bilateral fractures. There were 2 Type 1 fractures (0.2% of split sites), 8 Type 2 fractures (0.8% of split sites), and twenty-six Type 3 fractures (2.3% of split sites). Type 1 unfavorable fractures are difficult to deal with, but Types 2 and 3 are generally manageable and they have no significant impact on the final outcomes. The new classification can effectively guide treatment strategies for unfavorable fractures. Severe cases of unfavorable fractures are rare, and most unfavorable fracture cases have a positive prognosis if correctly treated in time., Competing Interests: The authors report no conflicts of interest., (Copyright © 2021 by Mutaz B. Habal, MD.)

Abstract: Bilateral sagittal split osteotomy is a routine procedure with predictable and well-known complications. The authors report a thitherto unreported complication of bilateral sagittal split osteotomy presenting as a postoperative sialocele of submandibular salivary gland tissue in the floor of the mouth. The sialocele was probably caused by overinstrumentation and injury to sublingual salivary tissues or Wharton's duct during bicortical drilling or screw fixation. This iatrogenic sialocele was managed conservatively with multiple aspiration and compression dressings. Although rare and unreported so far this complication may be included in the preoperative consent process., Competing Interests: The authors report no conflicts of interest., (Copyright © 2022 by Mutaz B. Habal, MD.)