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Background and objectives: The need to evaluate the condylar remodeling after orthognathic surgery, using three-dimensional (3D) images and volume rendering techniques in skeletal Class III patients has been emphasized. The study examined condylar positional, structural, and volumetric changes after bimaxillary or single-jaw maxillary orthognathic surgeries in skeletal Class III patients using the cone-beam computed tomography. Materials and Methods: Presurgical, postsurgical, and one-year post-surgical full field of view (FOV) cone-beam computed tomography (CBCT) images of 44 patients with skeletal Class III deformities were obtained. Group 1 underwent a bimaxillary surgery (28 patients: 24 females and 4 males), with mean age at the time of surgery being 23.8 ± 6.0 years, and Group 2 underwent maxillary single-jaw surgery (16 patients: 8 females and 8 males), with mean age at the time of surgery being 23.7 ± 5.1 years. After the orthognathic surgery, the CBCT images of 88 condyles were evaluated to assess their displacement and radiological signs of bone degeneration. Three-dimensional (3D) condylar models were constructed and superimposed pre- and postoperatively to compare changes in condylar volume. Results: Condylar position was found to be immediately altered after surgery in the maxillary single-jaw surgery group, but at the one-year follow-up, the condyles returned to their pre-surgical position. There was no significant difference in condylar position when comparing between pre-surgery and one-year follow-up in any of the study groups. Condylar rotations in the axial and coronal planes were significant in the bimaxillary surgery group. No radiological signs of condylar bone degeneration were detected one year after the surgery. Changes in condylar volume after surgery were found to be insignificant in both study groups. Conclusions: At one year after orthognathic surgery, there were no significant changes in positional, structural, or volumetric statuses of condyles.

Condylar-base-associated multiple mandibular fractures are more prevalent than single ones. Direct trauma to mandibular symphysis, body or angle are prone to induce indirect condylar fracture. However, little is known about the effects of various rigid internal fixation modalities in condylar base for relevant multiple mandibular fractures, especially when we are confused in the selection of operative approach. Within the finite element analysis, straight-titanium-plate implanting positions in condylar base contained posterolateral zone (I), anterolateral zone (II), and intermediate zone (III). Von Mises stress (SS) in devices and bone and mandibular displacement (DT) were solved, while maximum values (SS max and DT max ) were documented. For rigid internal fixation in condylar-base-and-symphysis fractures, I + II modality exhibited least SS max in screws and cortical bone and least DT max , I + III modality exhibited least SS max in plates. For rigid internal fixation in condylar-base-and-contralateral-body fractures, I + III modality exhibited least SS max in screws and cortical bone, I + II modality exhibited least SS max in plates and least DT max . For rigid internal fixation in condylar-base-and-contralateral-angle fractures, I + III modality exhibited least DT max . The findings suggest that either I + II or I + III modality is a valid guaranty for rigid internal fixation of condylar base fractures concomitant with symphysis, contralateral body or angle fractures. Graphical Abstract

ObjectsChanges in condylar position and morphology after mandibular reconstruction are important to aesthetic and functional rehabilitation. We evaluated changes in condylar position and morphology at different stages after mandibular reconstruction using vascularized fibular free flap with condyle preservation.Materials and methodsA total of 23 patients who underwent mandibular reconstruction with fibular flap were included in this retrospective study. CT data of all patients were recorded before surgery (T0), 7 to 14 days after surgery (T1), and at least 6 months after surgery (T2). Five parameters describing the condylar position and 4 parameters describing the morphology were measured in sagittal and coronal views of CT images. The association between clinical characteristics and changes in condylar position and morphology was analyzed. A finite element model was established to investigate the stress distribution and to predict the spatial movement tendency of the condyle after reconstruction surgery.ResultsThe condylar position changed over time after mandibular reconstruction. The ipsilateral condyles moved inferiorly after surgery (T0 to T1) and continually move anteriorly, inferiorly, and laterally during long-term follow-up (T1 to T2). Contrary changes were noted in the contralateral condyles with no statistical significance. No morphological changes were detected. The relationship between clinical characteristics and changes in condylar position and morphology was not statistically significant. A consistent result was observed in the finite element analysis.ConclusionCondylar positions showed obvious changes over time after mandibular reconstruction with condylar preservation. Nevertheless, further studies should be conducted to evaluate the clinical function outcomes and condylar position.Clinical relevanceThese findings can form the basis for the evaluation of short-term and long-term changes in condylar position and morphology among patients who have previously undergone mandibular reconstruction by FFF with condyle preservation.

Condylar resorption is a feared complication of orthognathic surgery. This study investigated condylar resorption in a cohort of 200 patients This allowed for a powerful update on incidence and risk factors. 9.5% of patients developed resorption. These patients had on average, 17% volume loss with 3.9 mm ramal height loss and 3.1 mm posterior mandibular displacement. 2% of patients had bilateral resorption. Univariable analysis identified a younger age, a bimaxillary + genioplasty procedure, larger mandibular advancements, upward movements of the distal segment, a higher counterclockwise pitch of the distal segment, smaller preoperative condylar volumes and a higher anterior/posterior lower facial height ratio as risk factors on a patient level. Univariable analysis on a condylar level also identified compressive movements of the ramus and a higher mandibular plane angle as risk factors. Using machine learning for the multivariable analysis, the amount of mandibular advancement was the most important predictor for condylar resorption. There were no differences in preoperative mandibular, ramal or condylar shape between patients with or without resorption. These findings suggest condylar resorption may be more common than thought. Identifying risk factors allows surgical plans to be adjusted to reduce the likelihood of resorption, and patients can be more selectively screened postoperatively.

Objectives To assess the effect of patient positioning and general anesthesia on the condylar position in orthognathic surgery. Materials and methods This prospective study included patients undergoing orthognathic surgery between 2019 and 2020. Four weeks prior to surgery (T0) cone-beam computed tomography (CBCT) scans and intra-oral scans (IOS) were acquired in an upright position. Additionally, two IOS were acquired in the operating theatre, one before (T1) and one after (T2) general anaesthesia in supine position. The condylar position was analysed by matching the mandible from CBCT data with IOS at T1, T2 and T3, calculating the spatial differences at the level of lateral condylar points. Results Based on 32 patients, patient positioning and general anesthesia on condylar position significantly affected condylar position. In supine position, the condyles moved primarily in the cranial direction by 0.94 ± 0.92 mm ( p  < 0.01). After anesthesia, the condyles moved posteriorly by 0.20 ± 0.45 mm ( p  = 0.02). These changes in condylar position resulted in the occlusal plane of the mandible being positioned more cranially (2.31 ± 2.61 mm; p  < 0.01), anteriorly (0.70 ± 1.32 mm; p  = 0.04), and counterclockwisely pitched (-1.42 ± 2.25°; p  = 0.02). Conclusion The present study demonstrated that both supine position and general anesthesia significantly influenced the condylar position, the mandibular position, and, subsequently, the surgical accuracy of orthognathic surgery. Clinical relevance Surgeons should take these effects into consideration when planning orthognathic surgery as this might lead to under- or overcorrections.

Objectives Mandibular fractures, especially at the parasymphysis and angle, significantly affect the temporomandibular joint (TMJ) due to remodeling. This study assesses changes in condyle volume, morphology, and position after open reduction and internal fixation (ORIF) using 3D analysis methods. Materials and methods A retrospective study evaluated 16 patients (11 males, 5 females; mean age: 33.63 years) with parasymphysis fractures, categorized into isolated (PS-type) and those with angle involvement (A-type). Preoperative and postoperative CBCT scans (minimum 6-month follow-up) were analyzed. Volumetric, linear, and angular changes in the condyle were assessed on the fractured and non-fractured sides. Results Significant postoperative condylar volume increase was observed on both fractured ( p  = 0.0081) and non-fractured sides ( p  = 0.0453). In PS-type fractures, condylar volume ( p  = 0.0156) and height ( p  = 0.0352) significantly increased on the fractured side, with a marked inter-side volumetric difference ( p  = 0.0232). A-type fractures showed a significant increase in sagittal condylar position on the non-fractured side ( p  = 0.0078). No other parameters showed significant change across or within groups. Correlation analyses revealed no significant association between condylar volume change and patient age or follow-up time. Conclusion TMJ remodeling after ORIF varies by fracture type. Isolated parasymphysis fractures caused significant increases in condylar volume and height. Angle fractures involvement showed greater sagittal positional. These results highlight the impact of fracture location and mechanical force distribution on adaptive remodeling.

Background and Objectives: The most popular surgical procedures among orthognathic surgeries for Class II and III patients are Le Fort 1 osteotomy for the maxilla and bilateral sagittal split ramus osteotomy (BSSRO) for the mandible. Keeping the condyle in its proper place during fixation is one of the difficulties of orthognathic surgery. One of the worst post-orthognathic surgery consequences in the temporomandibular joint (TMJ) area may be condylar resorption. Condylar remodeling refers to a group of processes that occur in reaction to forces and stress placed on the temporomandibular joint in order to preserve morphological, functional, and occlusal balance. A systematic review of the literature was performed with the aim of identifying the mandibular condylar component of TMJ changes after orthognathic surgery in class II and III patients. Materials and Methods: An electronic search was carried out using the PubMed, Cochrane Library, and Google Scholar, databases. The inclusion criteria included trials in non-growing patients upon whom orthognathic surgery was performed due to Angle II or Angle III classes malocclusion; in addition, a CT or cone beam computed tomography (CBCT) scan was performed before and after surgery to track the mandibular condylar component of TMJ changes. The quality of the studies was evaluated by two independent authors. The risk of bias was assessed by using the Downs and Black checklist. Results: The electronic and manual literature search yielded 12 studies that fulfilled all necessary inclusion criteria. Observed studies were evaluated as good (3), fair (8), and poor (1) quality. Two studies evaluated class II patients, six studies observed class III patients, and four studies were comparative. Most of the studies evaluated condyle angle and space changes, and the condylar surface and volume changes were also observed. However, the methodology of evaluation in the publications differs. Conclusions: Reduction of bone density, especially in class II patients, and morphological condyle reshaping, with the apposition of the bone, is the main adaptive mechanism after orthognathic surgery. However, all of the studies we examined were conducted using different methods of evaluation, measurement, and reference points.

Purpose Preoperative virtual planning and osteosynthesis with patient-specific implants (PSIs) have become a quotidian approach to many maxillofacial elective surgery setups. When a process is well-organized, a similar approach can be harnessed to serve the needs of exact primary reconstructions, especially in midfacial trauma cases. PSI osteosynthesis of the mandible is, however, more challenging because a mirror technique of the facial sides is often unreliable due to inherent lack of symmetry, and movement of the mandible increases the risk of loosening of the osteosynthesis. The purpose of this study was to present clinical results of the Helsinki protocol concept of utilizing PSIs in the primary surgery of unilateral mandibular subcondylar fractures as the first publication on the subject. Methods A single-center study of a new Helsinki protocol is presented for surgical treatment of subcondylar mandibular fractures using patient-specific, titanium-milled repositator plates. Ten patients with dislocated subcondylar mandibular fractures received surgery and osteosynthesis with PSI via a retromandibular approach. Results Clinical and radiological outcomes were excellent; none of the patients had fixation-related major complications or developed postoperative malocclusion. Conclusions Study results show that the Helsinki protocol, treating mandibular condylar fractures primarily with PSI plates, is a viable treatment option.

Background Mandibular condyle fractures (MCFs) are common injuries, often resulting from trauma and leading to functional complications. Treatment approaches remain debated, with extracorporeal fixation emerging as a potential alternative to conventional methods. This study explores the effectiveness and outcomes of this technique to guide clinical decision-making. Materials and methods A comprehensive search was conducted across PubMed, EMBASE, and BVS (VHL) for studies published until August 2024. The review included observational studies and clinical trials that assessed postoperative complications following extracorporeal fixation in MCFs. Results Thirty-one studies, comprising 436 participants, were included. Data were extracted on trauma etiology, fracture classification, surgical approaches, and complications such as condylar resorption, which was the most common (18.58%). The studies varied in surgical techniques, with submandibular (40.62%) and retromandibular (37.5%) accesses being the most common. Osteosynthesis materials such as miniplates, screws, and wires were frequently used. Follow-up durations ranged from immediate post-operative periods to 15 years. The quality assessment revealed fair to moderate study quality, with observational studies generally showing methodological limitations, such as sample size issues and heterogeneity in surgical technique and follow-up. Despite concerns about condylar resorption and temporomandibular joint dysfunction, most studies reported that these complications did not significantly affect function or occlusion. Conclusions Extracorporeal fixation of MCFs offers a promising alternative in cases with limited condylar access where conventional methods may fail. Despite a higher risk of condylar resorption, studies suggest minimal long-term functional impairment. This technique remains viable for complex fractures. However, robust clinical trials are needed to evaluate long-term outcomes, particularly regarding resorption and postoperative recovery, given their potential to affect mandibular function, occlusion, and temporomandibular joint health.

Objectives A retrospective cohort study was conducted to compare the treatment outcomes between arthroscopic disc repositioning and suturing surgery, and conservative treatment (without disc repositioning) in juvenile patients with anterior disc displacement without reduction (ADDwoR) and temporomandibular joint osteoarthritis (TMJOA). Methods Patients treated with arthroscopic surgery (surgery group) between March 2022 and March 2023, and those treated with conservative therapy (control group) between July 2014 and August 2022 were included. The patients were assessed clinically and with CBCT before and after the treatments (minimum interval of 6 months). Results A total of 38 patients were included in the study, with 19 patients in each of the groups. The postoperative mouth opening and joint pain improved significantly in both groups ( P  < 0.05), and there was no significant difference between them ( P  > 0.05). Besides clinical symptom relief, both treatments could promote regenerative condylar remodeling. More importantly, the increase in condylar head height and volume in the surgery group was significantly larger than those in the control group ( P  < 0.001). The occurrence of regenerative condylar remodeling in the surgery group (96.6%) was significantly higher than that in the control group (68.4%, P  < 0.001). However, the occurrence of condylar regeneration was exclusively observed in the surgery group. Conclusions The arthroscopic surgery has comparable effect to the conservative treatment on improving clinical symptoms, while it has better regenerative condylar remodeling results compared to the conservative treatment. Clinical Relevanve This study demonstrated that arthroscopic surgery was superior to conservative treatment in promoting regenerative condylar remodeling, which is of significance to guide the treatment decision of juvenile patients with ADDwoR and TMJOA.