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Introduction: Craniopharyngiomas are usually slow growing, benign epithelial tumors, arising from cell remnants of Rathke's pouch with its ultimate site of origin being the embryologic stomadeum. Although considered WHO grade I tumors, they are often locally aggressive. However, malignant transformation is extremely rare. Until now, 42 cases of malignant craniopharyngioma have been reported. In this article, the interdisciplinary, i.e. neurosurgical and maxillofacial, approach to a case of secondary malignant craniopharyngioma with multiple recurrences is discussed.Case report A 73-year-old woman with a history of recurrent, extracranially expanding craniopharyngioma was referred to the department of Neurosurgery following the MRI finding of a 7th tumor recurrence, located at the level of the right lateral orbital wall. Previously, the patient had already undergone five surgical resections and three radiotherapeutic treatments elsewhere. Histopathological examination revealed an adamantinomatous craniopharyngioma with sites of malignant transformation. Tumor resection with exenteration of the right eye was performed with an immediate reconstruction using a PEEK-PSI (Patient Specific Implant) and anterolateral thigh flap. Histopathological examination confirmed the diagnosis of craniopharyngioma with malignant transformation. Conclusions: Malignant transformation in a craniopharyngioma is uncommon but has a poor prognosis. The assumed correlation between radiotherapy and malignant transformation is not yet clearly established. Therefore, radiotherapy remains a good choice to reduce recurrence of a benign cranopharyngioma. PEEK implantation seems a safe option for allogenic reconstruction in patients with large maxillofacial defects. In complex cases the benefit of a multidisciplinary approach should not be underestimated.

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., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

The aim of this study was to assess the morphological characteristics of the coronoid process (CP) and define coronoid hyperplasia (CH) using cadaveric mandibles of a Caucasian population. A sample of 151 adult dry cadaveric mandibles (302 CPs) was acquired. Three distances were measured, which included the width, height, and length of CP. The surface area measurements involved area A: above the width distance line; area B: between incisura mandibulae-Alveolar ridge line and width distance line; area C: between distance lines of width and height. Finally, angulations of the CP and gonial angles were identified. Both length and surface area A + B acted as hyperplastic indicators. Based on the selection criteria, a sample of 197 CPs was included. The hooked shape (59%) was most commonly observed. No significant difference existed between left and right sides (p > 0.05). The mean values of length and surface area A + B were 2.2 ± 0.3 cm and 3.3 ± 0.8 cm 2 , and any values above 2.7 cm (n = 5 CPs- 2.5%) and 5.0 cm 2 (n = 9 CPs- 4.6%) were described as hyperplastic, respectively. The presented data could act as quantitative reference for differentiating between normal and hyperplastic conditions., (© 2023. The Author(s).)

Objectives: To investigate whether variations in head positioning may influence the reproducibility of cone-beam CT (CBCT) three-dimensional (3D) segmented models of the mandibular condyle., Methods: Five fresh frozen cadaver heads were scanned in four different positions: reference position (RP) and a set of three tilted alternative head positions (AP) in anteroposterior direction (AP1: 2 cm anterior translation, AP2: 5° pitch rotation, AP3: 10° pitch rotation). Surface models of mandibular condyles were constructed and compared with the condylar reference position using voxel-based registration. Descriptive statistics and a linear mixed-effects model were performed to compare condylar volumetric differences and root mean square (RMS) distance between surfaces of AP vs RP., Results: The mean differences in condylar volumes of AP vs RP were 14.1 mm³ (95% CI [-79.3, 107.4]) for AP1, 1.0 mm³ (95% CI [-87.2, 89.2]) for AP2 and 0.1 mm³ (95% CI [-88.3, 88.4]) for AP3. Mean and absolute volumetric differences did not exceed earlier reported intraoperator differences of 30 mm³. The RMS distance values obtained per group were 0.12 mm (95% CI [0.05,0.20]) for AP1, 0.17 mm (95% CI [0.10, 0.22]) for AP2 and 0.17 mm for AP3 (95% CI [0.10,0.22]). The confidence intervals (CI) for RMS distance remained far below the threshold for clinical acceptability (0.5 mm)., Conclusions: Within the limits of the present study, it is suggested that tilted head positions may affect the reproducibility of 3D condylar segmentation, thereby influencing outcome in repeated CBCT scanning. Nevertheless, observed differences are unlikely to have a meaningful impact on clinical patient diagnosis and management.

Background: Arthroscopy is a minimally invasive diagnostic tool and treatment strategy in patients suffering from temporomandibular disorders (TMD) when conservative treatment fails. This study aimed to find specific variables on pre-operative MRI or during arthroscopy that could predict success of arthroscopic lysis and lavage., Methods: This retrospective analysis compared pre-operative maximum interincisal opening (MIO), pain and main complaint (pain, limited MIO or joint sounds) with results at short-term and medium-term follow-up (ST and MT respectively). Different variables scored on MRI or arthroscopy were used to make a stepwise regression model, subsequently a combined analysis was conducted using variables from both MRI and arthroscopy., Results: A total of 47 patients (50 joints) met the inclusion criteria. The main complaint improved by 62 and 53% at ST and MT respectively. The absolute or probable absence of a crumpled disc scored on MRI predicted success at ST and MT (p = 0.0112 and p = 0.0054), and remained significant at MT in the combined analysis (p = 0.0078). Arthroscopic findings of degenerative joint disease predicted success at ST (p = 0.0178), absolute or probable absence of discal reduction scored during arthroscopy significantly predicted success in the combined analysis at ST (p = 0.0474)., Conclusion: To improve selection criteria for patients undergoing an arthroscopic lysis and lavage of the TMJ, future research might focus on variables visualized on MRI. Although more research is needed, disc shape and in particular the absolute or probable absence of a crumpled disc might be used as predictive variable for success., (© 2022. The Author(s).)

Objective: To develop and validate a layered deep learning algorithm which automatically creates three-dimensional (3D) surface models of the human mandible out of cone-beam computed tomography (CBCT) imaging., Materials & Methods: Two convolutional networks using a 3D U-Net architecture were combined and deployed in a cloud-based artificial intelligence (AI) model. The AI model was trained in two phases and iteratively improved to optimize the segmentation result using 160 anonymized full skull CBCT scans of orthognathic surgery patients (70 preoperative scans and 90 postoperative scans). Finally, the final AI model was tested by assessing timing, consistency, and accuracy on a separate testing dataset of 15 pre- and 15 postoperative full skull CBCT scans. The AI model was compared to user refined AI segmentations (RAI) and to semi-automatic segmentation (SA), which is the current clinical standard. The time needed for segmentation was measured in seconds. Intra- and inter-operator consistency were assessed to check if the segmentation protocols delivered reproducible results. The following consistency metrics were used: intersection over union (IoU), dice similarity coefficient (DSC), Hausdorff distance (HD), absolute volume difference and root mean square (RMS) distance. To evaluate the match of the AI and RAI results to those of the SA method, their accuracy was measured using IoU, DSC, HD, absolute volume difference and RMS distance., Results: On average, SA took 1218.4s. RAI showed a significant drop (p<0.0001) in timing to 456.5s (2.7-fold decrease). The AI method only took 17s (71.3-fold decrease). The average intra-operator IoU for RAI was 99.5% compared to 96.9% for SA. For inter-operator consistency, RAI scored an IoU of 99.6% compared to 94.6% for SA. The AI method was always consistent by default. In both the intra- and inter-operator consistency assessments, RAI outperformed SA on all metrics indicative of better consistency. With SA as the ground truth, AI and RAI scored an IoU of 94.6% and 94.4%, respectively. All accuracy metrics were similar for AI and RAI, meaning that both methods produce 3D models that closely match those produced by SA., Conclusion: A layered 3D U-Net architecture deep learning algorithm, with and without additional user refinements, improves time-efficiency, reduces operator error, and provides excellent accuracy when benchmarked against the clinical standard., Clinical Significance: Semi-automatic segmentation in CBCT imaging is time-consuming and allows user-induced errors. Layered convolutional neural networks using a 3D U-Net architecture allow direct segmentation of high-resolution CBCT images. This approach creates 3D mandibular models in a more time-efficient and consistent way. It is accurate when benchmarked to semi-automatic segmentation., (Copyright © 2021. Published by Elsevier Ltd.)

Purpose: Nonsurgical treatment of mandibular fractures secondary to medication-related osteonecrosis of the jaw (MRONJ) or osteoradionecrosis (ORN) mostly results in nonunion, whereas nonsurgical fracture treatment of atrophic fractures can achieve favorable results in selected cases. The aim of this study was to compare callus formation in pathological mandibular fractures due to MRONJ, ORN, or extreme mandibular atrophy., Methods: A retrospective cohort study reviewing the medical records of all MRONJ-, ORN-, or atrophy-related fractures treated at the departments of maxillofacial surgery in the Leuven or Lille university hospitals between 2010 and 2019 was undertaken. The primary predictor variable in this study was disease state (MRONJ, ORN, or extreme mandibular atrophy). The primary outcome variable was callus formation after 1 month of follow-up (present, absent). Additional study variables measured included patient age and gender. T-tests, Fisher exact tests, and multiple logistic regression were used for statistical analysis. The significance level was set at P < .05., Results: Seventy patients were analyzed (12 MRONJ cases, 54 ORN fractures, 4 atrophic fractures). The callus formation prevalence in nonsurgically approached fractures secondary to ORN and MRONJ after 1 month of follow-up was 3.03% (2/66 cases). In contrast, callus was detected in all patients in the mandibular atrophy-related fracture group. Osteonecrosis was statistically correlated with impaired callus formation (P = .0121)., Conclusion: Whereas one would expect indirect fracture healing and thus callus formation to occur in all non-surgically treated fractures, our data demonstrate its absence in the majority of MRONJ- and ORN-related fractures. Multiple plausible explanations for this phenomenon were identified: periosteal damage with loss of callus-forming cells, compromised vasculature, and bacterial colonization., (Copyright © 2021 The American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

The aim of this retrospective observational study was to assess the potential agreement between independent magnetic resonance imaging (MRI) and arthroscopic findings and their respective contributions to a final diagnosis in patients with refractory temporomandibular joint disorders. Two dentomaxillofacial radiologists and two oral and maxillofacial surgeons scored 50 joints. All observers, who were blinded to additional clinical information, used a specific scoring form and selected one or more diagnostic labels. Agreement between MRI and arthroscopy and their contributions to the final diagnosis were assessed as primary outcomes using Fleiss' kappa. Intra-modality agreement and the correlation between signal intensity ratio (SIR) measurements on MRI and synovitis grading on arthroscopy were assessed as secondary outcomes. Agreement between MRI and arthroscopy was poor. A fair level of agreement was only reached for reduction capacity of the disc and disc perforation. Arthroscopic diagnostic labels matched better with the final diagnosis, suggesting a bigger contribution to that diagnosis. Higher SIR measurements correlated with higher synovitis grading scores for the retrodiscal tissue and the posterior band of the disc. Intra-modality agreement was better in arthroscopy. When blinded to clinical information, arthroscopy and MRI observations can lead to different conclusions. The diagnostic outcomes of both examinations should be considered and integrated into a final diagnosis., (Copyright © 2020 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

Automatic craniomaxillofacial (CMF) three dimensional (3D) dense phenotyping promises quantification of the complete CMF shape compared to the limiting use of sparse landmarks in classical phenotyping. This study assesses the accuracy and reliability of this new approach on the human mandible. Classic and automatic phenotyping techniques were applied on 30 unaltered and 20 operated human mandibles. Seven observers indicated 26 anatomical landmarks on each mandible three times. All mandibles were subjected to three rounds of automatic phenotyping using Meshmonk. The toolbox performed non-rigid surface registration of a template mandibular mesh consisting of 17,415 quasi landmarks on each target mandible and the quasi landmarks corresponding to the 26 anatomical locations of interest were identified. Repeated-measures reliability was assessed using root mean square (RMS) distances of repeated landmark indications to their centroid. Automatic phenotyping showed very low RMS distances confirming excellent repeated-measures reliability. The average Euclidean distance between manual and corresponding automatic landmarks was 1.40 mm for the unaltered and 1.76 mm for the operated sample. Centroid sizes from the automatic and manual shape configurations were highly similar with intraclass correlation coefficients (ICC) of > 0.99. Reproducibility coefficients for centroid size were < 2 mm, accounting for < 1% of the total variability of the centroid size of the mandibles in this sample. ICC's for the multivariate set of 325 interlandmark distances were all > 0.90 indicating again high similarity between shapes quantified by classic or automatic phenotyping. Combined, these findings established high accuracy and repeated-measures reliability of the automatic approach. 3D dense CMF phenotyping of the human mandible using the Meshmonk toolbox introduces a novel improvement in quantifying CMF shape.

Objectives: Three-dimensional models of mandibular condyles provide a way for condylar remodeling follow-up. The overall aim was to develop and validate a user-friendly workflow for cone beam CT (CBCT)-based semi-automatic condylar registration and segmentation., Methods: A rigid voxel-based registration (VBR) technique for registration of two post-operative CBCT-scans was tested. Two modified mandibular rami, with or without gonial angle, were investigated as the volume of interest for registration. Inter- and intraoperator reproducibility of this technique was tested on 10 mandibular rami of orthognathic patients by means of intraclass correlation coefficients (ICC's) and descriptive statistics of the transformation values from the VBR. The difference in reproducibility between the two modified rami was evaluated using a paired t -test ( p < 0.05). For the segmentation, eight fresh frozen cadaver heads were scanned with CBCT and micro-CT. These data were used to test the inter- and intraoperator reproducibility (ICC's) and accuracy (Bland-Altman plot) of a newly designed workflow based on semi-automated contour enhancement., Results: Excellent ICC's (0.94-0.99) were obtained for the voxel-based registration technique using both modified rami. If the gonial angle was not included in the volume of interest, there was a trend of increased operator error suggested by significant higher interoperator differences in translation values ( p = 0,0036). The segmentation workflow proved to be highly reproducible with excellent ICC's (0.99), low absolute mean volume differences between operators (23.19 mm 3 ), within operators (28.93 mm 3 ) and low surface distances between models of different operators (<0.20 mm). Regarding the accuracy, CBCT-models slightly overestimate the condylar volume compared to micro-CT., Conclusions: This study provides a validated user-friendly and reproducible method of creating three-dimensional-surface models of mandibular condyles out of longitudinal CBCT-scans.

Orthognathic surgery involving the mandible can lead to remodelling of the temporomandibular joint (TMJ). Cone beam computed tomography (CBCT) provides an easily accessible three-dimensional (3D) approach to study this entity. A systematic review of the literature was performed with the aim of identifying condylar remodelling analysis protocols using CBCT-derived 3D models. The search yielded 10 eligible studies. The systematic review identified three pillars of a condylar remodelling analysis protocol that were retrievable from each of the included studies: (1) registration, (2) segmentation, and (3) analysis. The studies lacked consensus on how these pillars should be transferred to their respective protocol. Through critical assessment, criteria for a universal condylar remodelling analysis are suggested: (1) performance of a regional voxel-based registration of baseline and postoperative CBCT scans using an anatomical region not prone to postoperative changes, (2) application of a (semi-)automated 3D segmentation algorithm, (3) performance of a combination of both volumetric and surface-based 3D condylar analysis, and (4) extensive validation of each step of the protocol. The homogenization of condylar remodelling analysis protocols and their incorporation into virtual planning software suites raises the potential for the inclusion of larger numbers of patients in future prospective studies in order to gain evidence-based data., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

The fibula free flap (FFF) has been a workhorse in maxillofacial reconstruction. High success rates of this technique are reported. However, identifying risk factors for flap failure and analyzing complications can open the way to better patient care. A retrospective analysis was conducted of all FFFs performed over a 20-year period at a low-volume single tertiary center to identify risk factors and postoperative complications. A total of 129 FFFs were included (122 mandible, 7 maxilla). Complete flap failure occurred in 12.4% and partial flap failure in 7.8% of patients. A significant relation was found between younger age and flap failure, and most failures were associated with venous thrombosis. In-hospital surgical complications occurred in 60.5%, in-hospital medical complications in 49.6%, and out-of-hospital complications in 77.5% of patients. The in-hospital reintervention rate was 27.1%, and including salvaged flaps, flap survival rate was 87.6%. Osteomyocutaneous FFF failure (complete 12.4%; partial 7.8%) is an important clinical reality in a low-volume head and neck reconstruction center resulting in an in-hospital reintervention rate of 27.1%. Postoperative complications are frequent, both surgical and out-hospital complications. These results provide a better understanding of the limitations of the FFF in a low-volume center and can be used to optimize care in this kind of setting.

The sagittal split ramus osteotomy is a key approach for treating dentofacial deformities. Although it delivers excellent results, the sagittal split ramus osteotomy is believed to induce stress to the temporomandibular joint. Potential stress inducers could be classified as intra- and postoperative factors resulting in an inflammatory response and molecular cascades, which initiate physiological remodeling. Occasionally, this process exceeds its capacity and causes pathological remodeling, through either degenerative joint disease or condylar resorption. Hard evidence on how orthognathic surgery causes inflammation and how this inflammation is linked to the spectrum of remodeling remains scarce. Current concepts on this matter are mainly based on clinical observations and molecular mechanisms are extrapolated from fundamental research in other body parts or joints. This perspective study provides an overview of current knowledge on molecular pathways and biomechanical effects in temporomandibular joint remodeling. It provides research directions that could lead to acquiring fundamental evidence of the relation of orthognathic surgery and inflammation and its role in remodeling. Performing osteotomies in animal models and identifying inflammatory mediators as well as their effect on the joint seem promising. Patients affected by pathological remodeling can also provide samples for histological as well as molecular analysis. Individual susceptibility analysis by linking certain suspect phenotypes to genetic variation could identify the cause and molecular pathway responsible for degenerative joint disease and condylar resorption, ultimately leading to clinically applicable treatment and prevention strategies.

After orthognathic surgery for class II dentofacial deformity, remodelling of the mandibular condyle will take place. In a number of cases, this may evolve towards a phenomenon of condylar resorption. Yet, studies on the occurrence of this complication after the correction of a class III deformity are scarce. A systematic review of the literature was performed with the aim of identifying reports on condylar resorption or remodelling after orthognathic surgery for class III dentofacial deformity. A search of the international databases yielded 12 eligible studies. Eight studies reported some degree of postoperative condylar remodelling, while symptoms of condylar resorption were only described in a limited group of patients. Thus, the literature may show evidence of condylar remodelling after orthognathic treatment of class III patients, and anecdotal reports of condylar resorption exist. The small sample sizes, heterogeneity in methods and outcomes, and use of two-dimensional radiographs indicate the need for updated long-term research. In the future, the use of cone beam computed tomography data for volumetric and morphological condylar analysis in combination with three-dimensional cephalometry may provide the opportunity to further elucidate this phenomenon and better characterize its aetiology., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Purpose: This report originated from the finding of metal artefacts on magnetic resonance images (MRI) which were not detected on panoramic radiography or cone beam computed tomography (CBCT) imaging. It was hypothesised that drills or implants might release metal particles during surgical procedures in the jawbones. Therefore, the aim was to assess whether dental implants or surgical drills might cause metal debris in the surrounding tissues., Materials and Methods: The experiment consisted of a postmortem and an antemortem model. A split-mouth design was carried out in a postmortem fresh frozen cadaver head. In the left mandible only the drill preparation sequence was performed, whereas in the right mandible, the drill sequence was followed by implant placement. Before surgery, the postmortem model underwent a baseline MRI acquisition. A second MRI (MRI2) was acquired after performing the osteotomies on both sides and implant placement on the right side. Finally, the implants were carefully removed, and a final MRI (MRI3) was acquired. Bone blocks containing the implant and osteotomy sites were isolated. For the antemortem model, a fresh frozen cadaver head was selected that already had implants in place. An implant in the anterior maxilla was removed and the surrounding bone block was isolated as well. A histological analysis was prepared for both models., Results: In the antemortem model, histological analysis showed irregular-shaped dark particles near the bone-implant interface consistent with metal debris. Additionally, in the postmortem model, both sites showed metal artefacts on MRI2 and MRI3, and by using a balanced fast field echo sequence, and histological analysis, the suspected particles of metal debris were confirmed on both sides of the mandible., Conclusions: Further studies should investigate the origin and extent of the metal debris following implant placement, as well as its clinical significance, possible risk factors and preventive measures., Competing Interests: Conflict of interest statement: The authors declare no financial disclosures or conflicts of interest.

Squamous odontogenic tumor is a rare benign epithelial odontogenic tumor of the jaw. Most are solitary lesions, although rare multifocal lesions have been described. Maxillary lesions have more aggressive behavior. Because of their benign character, these lesions are usually treated using a conservative surgical approach with curettage and surgical enucleation. This report describes the case of a 29-year-old woman with multifocal lesions who was initially treated with conservative surgical therapy. Early recurrence 6 months after surgery prompted more aggressive resection. This case is discussed in the context of current evidence related to the epidemiology, etiology, diagnosis, and therapy of squamous odontogenic tumors., (Copyright © 2017 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.)

The rupture of the anterior cruciate ligament is one of the most common orthopaedic injuries. This review gives an overview of the surgical treatment of the ACL rupture. A correct knowledge of the anatomy of the ACL is crucial in treating this injury. Recent studies describe the ACl as flat rather than divided in distinct structural bundles. Reconstructive and primary repair techniques can be used to approach this native anatomy. Reconstructive surgery of the ACL still is the golden standard in ACL surgery. An individualized approach is key and should be used. However, ACL reconstruction is not always a success. Return to preinjury of sports only reaches 65% and ACL-reconstructed knees are prone to osteoarthritis. Previous attempts at the primary repair of the ACL were archaic and had disappointing results. Modern diagnostics, operative and biological techniques and strict patient selection could initiate a revival of this technique.