An ex-vivo and in-vitro dynamic simulator for surgical and transcatheter mitral valve interventions.

PURPOSE: Minimally invasive mitral valve surgery (MIMVS) and transcatheter edge-to-edge repair (TEER) are complex procedures used to treat mitral valve (MV) pathologies, but with limited training opportunities available. To enable training, a realistic hemodynamic environment is needed. In this work we aimed to develop and validate a simulator that enables investigation of MV pathologies and their repair by MIMVS and TEER in a hemodynamic setting. METHODS: Different MVs were installed in the simulator, and pressure, flow, and transesophageal echocardiographic measurements were obtained. To confirm the simulator's physiological range, we first installed a biological prosthetic, a mechanical prosthetic, and a competent excised porcine MV. Subsequently, we inserted two porcine MVs-one with induced chordae tendineae rupture and the other with a dilated annulus, along with a patient-specific silicone valve extracted from echocardiography with bi-leaflet prolapse. Finally, TEER and MIMVS procedures were conducted by experts to repair the MVs. RESULTS: Systolic pressures, cardiac outputs, and regurgitations volumes (RVol) with competent MVs were 119 ± 1 mmHg, 4.78 ± 0.16 l min-1, and 5 ± 3 ml respectively, and thus within the physiological range. In contrast, the pathological MVs displayed increased RVols. MIMVS and TEER resulted in a decrease in RVols and mitigated the severity of mitral regurgitation. CONCLUSION: Ex-vivo modelling of MV pathologies and repair procedures using the described simulator realistically replicated physiological in-vivo conditions. Furthermore, we showed the feasibility of performing MIMVS and TEER at the simulator, also at patient-specific level, thus providing new clinical perspectives in terms of training modalities and personalized planning.

Automated calculation of ontology-based planning proposals: An application in reconstructive oral and maxillofacial surgery.

BACKGROUND: Structured modelling of surgical knowledge and its automated processing is still challenging. The aim of this work is to introduce a novel approach for automated calculation of ontology-based planning proposals in mandibular reconstruction and conduct a feasibility study. METHODS: The presented approach is composed of an RDF(S) ontology, a 3D mandible template and a calculator-optimiser algorithm to automatically calculate reconstruction proposals with fibula grafts. To validate the viability of the approach, a feasibility study was conducted on 164 simulated mandibular reconstructions. RESULTS: The ontology defines 244 different reconstruction variants and 80 analyses for optimization. In 146 simulated cases, a proposal could be automatically calculated (average time 8.79 ± 4.03 s). The assessments of the proposals by three clinical experts indicate the viability of the approach. CONCLUSIONS: Due to the modular separation between computational logic and domain knowledge, the developed concepts can be easily maintained, reused and adapted for other applications.

Concept for the Treatment of Class III Anomalies with a Skeletally Anchored Appliance Fabricated in the CAD/CAM Process-The MIRA Appliance.

OBJECTIVE: Intermaxillary elastics, anchored skeletally, represent a promising concept for treatment in adolescent patients with skeletal Class III anomalies. A challenge in existing concepts is the survival rate of the miniscrews in the mandible or the invasiveness of the bone anchors. A novel concept, the mandibular interradicular anchor (MIRA) appliance, for improving skeletal anchorage in the mandible, will be presented and discussed. CLINICAL CASE: In a ten-year-old female patient with a moderate skeletal Class III, the novel MIRA concept, combined with maxillary protraction, was applied. This involved the use of a CAD/CAM-fabricated indirect skeletal anchorage appliance in the mandible, with interradicularly placed miniscrews distal to each canine (MIRA appliance), and a hybrid hyrax in the maxilla with paramedian placed miniscrews. The modified alt-RAMEC protocol involved an intermittent weekly activation for five weeks. Class III elastics were worn for a period of seven months. This was followed by alignment with a multi-bracket appliance. DISCUSSION: The cephalometric analysis before and after therapy shows an improvement of the Wits value (+3.8 mm), SNA (+5°), and ANB (+3°). Dentally, a transversal postdevelopment in the maxilla (+4 mm) and a labial tip of the maxillary (+3.4°) and mandibular anterior teeth (+4.7°) with gap formation is observed. CONCLUSION: The MIRA appliance represents a less invasive and esthetic alternative to the existing concepts, especially with two miniscrews in the mandible per side. In addition, MIRA can be selected for complex orthodontic tasks, such as molar uprighting and mesialization.

3D-2D Distance Maps Conversion Enhances Classification of Craniosynostosis.

OBJECTIVE: Diagnosis of craniosynostosis using photogrammetric 3D surface scans is a promising radiation-free alternative to traditional computed tomography. We propose a 3D surface scan to 2D distance map conversion enabling the usage of the first convolutional neural networks (CNNs)-based classification of craniosynostosis. Benefits of using 2D images include preserving patient anonymity, enabling data augmentation during training, and a strong under-sampling of the 3D surface with good classification performance. METHODS: The proposed distance maps sample 2D images from 3D surface scans using a coordinate transformation, ray casting, and distance extraction. We introduce a CNN-based classification pipeline and compare our classifier to alternative approaches on a dataset of 496 patients. We investigate into low-resolution sampling, data augmentation, and attribution mapping. RESULTS: Resnet18 outperformed alternative classifiers on our dataset with an F1-score of 0.964 and an accuracy of 98.4%. Data augmentation on 2D distance maps increased performance for all classifiers. Under-sampling allowed 256-fold computation reduction during ray casting while retaining an F1-score of 0.92. Attribution maps showed high amplitudes on the frontal head. CONCLUSION: We demonstrated a versatile mapping approach to extract a 2D distance map from the 3D head geometry increasing classification performance, enabling data augmentation during training on 2D distance maps, and the usage of CNNs. We found that low-resolution images were sufficient for a good classification performance. SIGNIFICANCE: Photogrammetric surface scans are a suitable craniosynostosis diagnosis tool for clinical practice. Domain transfer to computed tomography seems likely and can further contribute to reducing ionizing radiation exposure for infants.

Impact of data synthesis strategies for the classification of craniosynostosis.

Introduction: Photogrammetric surface scans provide a radiation-free option to assess and classify craniosynostosis. Due to the low prevalence of craniosynostosis and high patient restrictions, clinical data are rare. Synthetic data could support or even replace clinical data for the classification of craniosynostosis, but this has never been studied systematically. Methods: We tested the combinations of three different synthetic data sources: a statistical shape model (SSM), a generative adversarial network (GAN), and image-based principal component analysis for a convolutional neural network (CNN)-based classification of craniosynostosis. The CNN is trained only on synthetic data but is validated and tested on clinical data. Results: The combination of an SSM and a GAN achieved an accuracy of 0.960 and an F1 score of 0.928 on the unseen test set. The difference to training on clinical data was smaller than 0.01. Including a second image modality improved classification performance for all data sources. Conclusions: Without a single clinical training sample, a CNN was able to classify head deformities with similar accuracy as if it was trained on clinical data. Using multiple data sources was key for a good classification based on synthetic data alone. Synthetic data might play an important future role in the assessment of craniosynostosis.

A Radiation-Free Classification Pipeline for Craniosynostosis Using Statistical Shape Modeling.

BACKGROUND: Craniosynostosis is a condition caused by the premature fusion of skull sutures, leading to irregular growth patterns of the head. Three-dimensional photogrammetry is a radiation-free alternative to the diagnosis using computed tomography. While statistical shape models have been proposed to quantify head shape, no shape-model-based classification approach has been presented yet. METHODS: We present a classification pipeline that enables an automated diagnosis of three types of craniosynostosis. The pipeline is based on a statistical shape model built from photogrammetric surface scans. We made the model and pathology-specific submodels publicly available, making it the first publicly available craniosynostosis-related head model, as well as the first focusing on infants younger than 1.5 years. To the best of our knowledge, we performed the largest classification study for craniosynostosis to date. RESULTS: Our classification approach yields an accuracy of 97.8 %, comparable to other state-of-the-art methods using both computed tomography scans and stereophotogrammetry. Regarding the statistical shape model, we demonstrate that our model performs similar to other statistical shape models of the human head. CONCLUSION: We present a state-of-the-art shape-model-based classification approach for a radiation-free diagnosis of craniosynostosis. Our publicly available shape model enables the assessment of craniosynostosis on realistic and synthetic data.

3D-Guided Face Manipulation of 2D Images for the Prediction of Post-Operative Outcome After Cranio-Maxillofacial Surgery.

Cranio-maxillofacial surgery often alters the aesthetics of the face which can be a heavy burden for patients to decide whether or not to undergo surgery. Today, physicians can predict the post-operative face using surgery planning tools to support the patient's decision-making. While these planning tools allow a simulation of the post-operative face, the facial texture must usually be captured by another 3D texture scan and subsequently mapped on the simulated face. This approach often results in face predictions that do not appear realistic or lively looking and are therefore ill-suited to guide the patient's decision-making. Instead, we propose a method using a generative adversarial network to modify a facial image according to a 3D soft-tissue estimation of the post-operative face. To circumvent the lack of available data pairs between pre- and post-operative measurements we propose a semi-supervised training strategy using cycle losses that only requires paired open-source data of images and 3D surfaces of the face's shape. After training on "in-the-wild" images we show that our model can realistically manipulate local regions of a face in a 2D image based on a modified 3D shape. We then test our model on four clinical examples where we predict the post-operative face according to a 3D soft-tissue prediction of surgery outcome, which was simulated by a surgery planning tool. As a result, we aim to demonstrate the potential of our approach to predict realistic post-operative images of faces without the need of paired clinical data, physical models, or 3D texture scans.

Knowledge Acquisition and Construction of a RDF-Ontology for Computer-Assisted Surgery.

The integration of surgical knowledge into virtual planning systems plays a key role in computer-assisted surgery. The knowledge is often implicitly contained in the implemented algorithms. However, a strict separation would be desirable for reasons of maintainability, reusability and readability. Along with the Department of Oral and Maxillofacial Surgery at Heidelberg University Hospital, we are working on the development of a virtual planning system for mandibular reconstruction. In this work we describe a process for the structured acquisition and representation of surgical knowledge for mandibular reconstruction. Based on the acquired knowledge, an RDF(S) ontology was created. The ontology is connected to the virtual planning system via a SPARQL interface. The described process of knowledge acquisition can be transferred to other surgical use cases. Furthermore, the developed ontology is characterised by a reusable and easily expandable data model.

Accuracy of 3D printing compared with milling - A multi-center analysis of try-in dentures.

OBJECTIVES: In recent years, computer-aided design/computer-aided manufacturing (CAD/CAM) has been used to produce removable complete dentures. Most workflows include fabrication of milled or 3D-printed try-in prostheses. 3D-printing accuracy is affected by laboratory-specific and operator-dependent factors. This international five-center study sought to compare the accuracy of 3D-printed and milled try-in dentures. METHODS: The construction file of a maxillary removable complete denture was selected as a reference. Eight try-in dentures were 3D printed at each of the five centers. Each center used their own printer (Objet260 Connex, Stratasys; MAX, Asiga; Anycubic Photon, Anycubic 3D; PRO2, Asiga and cara Print 4.0, Kulzer) along with their own material, printing settings, post-processing and light-curing parameters. At center 2, eight try-in dentures were milled to serve as a benchmark (PrograMill PM7, Ivoclar Vivadent). Dentures were scanned and aligned to the reference file using best-fit algorithms. Geometric accuracy was analyzed using the root mean square value (trueness) and standard deviation (precision) of the distributed absolute mesh deviations. Mean values of the five sets of printed dentures and the single set of milled dentures were compared. RESULTS: Milled dentures showed a mean trueness of 65 ±â€¯6 µm and a mean precision of 48 ±â€¯5 µm. Thus, they were significantly more accurate than the 3D-printed dentures in four out of five centers. In mean absolute numbers, 3D printing was less true than milling by 17-89 µm and less precise by 8-66 µm. CONCLUSIONS: Although milling remains the benchmark technique for accuracy, differences between milled and 3D-printed dentures were non-significant for one printing center. Furthermore, the overall performance of 3D printing at all centers was within a clinically acceptable range for try-in prostheses. CLINICAL SIGNIFICANCE: The accuracy of 3D printing varies widely between and within laboratories but nonetheless lies within the range of accuracy of conventional manufacturing methods.

Wound closure and alveoplasty after preventive tooth extractions in patients with antiresorptive intake-A randomized pilot trial.

OBJECTIVES: To compare success rates between the sub-periosteal prepared (SPP) muco-periosteal flap and the epi-periosteal prepared (EPP) mucosa flap and the feasibility of alveoplasty after surgical tooth extractions in patients undergoing/after antiresorptive treatment. SUBJECTS: Patients with an indication for preventive tooth extraction undergoing/after antiresorptive treatment were enrolled over a 24-month period in a parallel-group randomized clinical pilot trial and randomly assigned for primary wound closure to either the SPP or the EPP group. The primary outcome was treatment failure 8 weeks after surgery. To assess the feasibility of alveoplasty, necrotic bone changes at the time point of tooth extraction were evaluated. RESULTS: One hundred and sixty patients were randomized to the SSP (n = 82) or the EPP (n = 78) group. One hundred and fifty-seven patients met the primary endpoint 8 weeks after surgery with five treatment failures for the SPP group (6.3%) and 18 (23.4%) for the EPP group (p = .004). A significant relationship (p < .0001) was observed between symptomatic teeth and non-vital bone found in 54.8% of all biopsies. CONCLUSIONS: The strong superiority of the muco-periosteal flap as primary wound closure revealed the feasibility and effectiveness of the study. The large number of necrotic biopsies emphasizes the importance of alveoplasty as a preventive measure.

The Influence of Different Graft Designs of Intraoral Bone Blocks on Volume Gain in Bone Augmentation Procedures: An In Vitro Study.

PURPOSE: Intraoral bone blocks from the external oblique are the gold standard for alveolar ridge bone grafting, but the limited amount of available bone limits their use for larger defects. The objective of this study was to compare whether different graft designs of intraoral bone blocks could affect the amount of bone gain. MATERIALS AND METHODS: In this in vitro study, 20 pig jaws were used to harvest bone blocks and subsequently augment single-wall bone defects. Each bone graft was first used as a full block, and then the same block was divided lengthwise into two blocks, with one block fixed at a distance as a cortical shell and the second block particulated to fill the gap between graft and bone. Three stereolithographic (STL) files (pre-OP, full block, split block) were generated using an intraoral scanner. All STL files were evaluated for volume gain and horizontal bone dimensions. RESULTS: A mean volume gain of 0.36 cm2 (SD: 0.09) was achieved for the full block and 0.78 cm2 (SD: 0.14) for the split block using the same block. The difference was statistically significant (P < .0001). A mean horizontal bone gain of 4.37 mm (SD: 0.93) was achieved with a full block and 5.77 mm (SD: 0.85) with the shell technique (P < .0001). CONCLUSION: With the same amount of bone removed, first as a full block and then as a split block, the split-block technique achieved a significantly higher bone gain compared with the full-block design.

Image-guided percutaneous sclerotherapy of venous malformations of the head and neck: Clinical and MR-based volumetric mid-term outcome.

OBJECTIVE: To report the clinical and MRI-based volumetric mid-term outcome after image guided percutaneous sclerotherapy (PS) of venous malformations (VM) of the head and neck. METHODS: A retrospective analysis of a prospectively maintained database was performed, including patients with VM of the head and neck who were treated with PS. Only patients with available pre- and post-interventional MRI were included into this study. Clinical outcome, which was subjectively assessed by the patients, their parents (for paediatric patients) and/or the physicians, was categorized as worse, unchanged, minor or major improvement. Radiological outcome, determined by MRI-based volumetric measurements, was categorized as worse (>10% increase), unchanged (≤10% increase to <10% decrease), minor (≥10% to <25% decrease), intermediate (≥25% to <50% decrease) or major improvement (≥50% decrease). RESULTS: Twenty-seven patients were treated in 51 treatment sessions. After a mean follow-up of 31 months, clinical outcome was worse for 7.4%, unchanged for 3.7% of the patients, while there was minor and major improvement for 7.4% and 81.5%, respectively. In the volumetric imaging analysis 7.4% of the VMs were worse and 14.8% were unchanged. Minor improvement was observed in 22.2%, intermediate improvement in 44.4% and major improvement in 11.1%. The rate of permanent complications was 3.7%. CONCLUSION: PS can be an effective therapy to treat the symptoms of patients with VMs of the head and neck and to downsize the VMs. MRI-based volumetry can be used to objectively follow the change in size of the VMs after PS. Relief of symptoms frequently does not require substantial volume reduction.

Accuracy of laser-melted patient-specific implants in genioplasty - A three-dimensional retrospective study.

PURPOSE: To assess the accuracy of laser-melted patient-specific implants (PSI) with regard to a preoperative virtual treatment plan for genioplasty based on a new analysis method without the use of landmarks. MATERIALS AND METHODS: A retrospective evaluation of a cohort of Class II and Class III patients who had undergone virtually planned orthognathic surgery (including genioplasty) was carried out. The preoperative virtual treatment plan and the postoperative outcome were fused to calculate the translational and rotational discrepancies between the 3D planning and the actual surgical outcome. RESULTS: The accuracy of left/right positioning was 0.25 ± 0.28 mm (p < 0.001), that of anterior/posterior positioning was 0.70 ± 0.64 mm (p < 0.001), and that of up/down-positioning was 0.45 ± 0.38 mm (p < 0.001). The rotational discrepancies were less than 2 deg. The virtually planned and postoperative positions of the chin differed significantly from each other (p < 0.001 for all rotational and translational discrepanices). CONCLUSION: The findings demonstrate that PSIs can transfer the planned virtual genioplasty into the operation theatre with small but significant deviations. However, since no conclusions can be drawn from the results regarding surgical success in terms of shaping the soft tissue profile as well as the esthetic result, no superiority of PSI over traditional plate osteosynthesis can be demonstrated.

Accuracy of patient-specific implants and additive-manufactured surgical splints in orthognathic surgery - A three-dimensional retrospective study.

INTRODUCTION: Because of the many limitations of conventional surgery planning for the treatment of orthognathic deformities, as well as advancements in computer-assisted planning, there is an urgent need for technical devices that transfer the surgical plan into the operating theatre. In this regard, additive-manufactured, patient-specific implants (PSI) and additive-manufactured interocclusal splints represent promising approaches. The aim of this retrospective study was to compare the accuracy of these two devices, with regard to preoperative virtual treatment planning for maxillary Le-Fort I advancement surgery using IPS CaseDesigner®, and based on a new analysis method without the use of landmarks. MATERIALS AND METHODS: A retrospective evaluation of 18 class III patients (n(PSI) = 9; n(splint) = 9), who had undergone virtually planned orthognathic surgery (including maxillary Le Fort I advancement), was performed. The preoperative treatment plan and the postoperative outcome were combined to calculate the translational and rotational discrepancies between the 3D planning and the actual surgical outcome. RESULTS: For the PSI and splint groups the accuracy of left/right positioning was 0.51 mm ± 0.48 and 1.11 mm ± 1.32 respectively. The accuracy of anterior/posterior positioning was 0.39 mm ± 0.26 and 1.42 mm ± 0.87, and that of up/down-positioning was 0.44 mm ± 0.31 and 0.62 mm ± 0.47. The rotational discrepancies were less than 2° in both groups. CONCLUSION: The findings demonstrate that both PSI and splint approaches can accurately transfer the virtual planning into the operating theatre. However, PSIs show an overall higher accuracy, especially for anterior/posterior translational movement (p < 0.002).

Midface correction in patients with Crouzon syndrome is Le Fort III distraction osteogenesis with a rigid external distraction device the gold standard?

INTRODUCTION: Le Fort III distraction osteogenesis with a rigid external distraction device is a powerful procedure to correct both exorbitism and impaired airways in faciocraniosynostosis. The aim of this study was to investigate treatment effect, perioperative parameters and volumetric outcomes after Le Fort III distraction osteogenesis in patients with Crouzon syndrome in a retrospective study design and to explore potential strengths and weaknesses of this procedure. MATERIALS AND METHODS: From June 2013 to February 2015, a total of nine children with Crouzon syndrome underwent Le Fort III distraction osteogenesis with a rigid external distraction device (RED device, KLS Martin, Tuttlingen, Germany). Along with perioperative parameters, sleep study reports, traditional cephalometric analysis, three-dimensional imaging and photographs were evaluated for severity of disease and therapeutic effect and structural and functional changes of the upper airway preoperatively, after device removal and one year postoperatively. RESULTS: Surgery for Le Fort III distraction was performed at a median age of 12.5 years (SD 2.5 months) with an average weight of 43.0 kg (SD 12.9 kg). Mean estimated blood loss was 535.7 ml (SD 128.1 ml), not requiring any red blood cell transfusions. Mean duration of surgery was 240 min (SD 30.6min), average hospital stay eight days (SD 0.5 days) with a planned median ICU stay of 1.7 days (SD 0.4 days) for all patients. There were a total of five minor complications. Exorbitism and Angle class III malocclusions were corrected in all patients. No patient showed velopharyngeal problems postoperatively. The average amount of distraction was 18.4 mm (14-26 mm). Average length of the distraction period was 18.3 days (SD 0.4 days), with a total distraction plus consolidation time of three months (SD 0.25 months). In two patients, vector correction was performed during distraction. A counterclockwise movement despite vector correction, clinically resulting in an open bite, was observed in one of these two patients. Eight of the nine patients showed a frontal overbite at the end of the distraction period. Cephalometric analysis revealed a significant increase of Sella-Nasion-Point A angle (SNA) from 76.0° (+/- 2.9; T1) to 86.0° (+/- 3.4; T2) (p = 0.006) and growth-related point A-Nasion-point B angle (ANB) from -4.8° (+/-3.7) to 5.7° (+/-4.8) (p = 0.001) from preoperatively to device removal and stable results one year postoperatively. Upper airway structure and respiratory function were improved clinically after the Le Fort III DO treatment in all cases with an average posterior airway space increase from 3199 mm3 (+/- 229.6 mm3) to 8917,7 ml (+/-415.1 mm3) (T1 to T2). Surgical outcome was judged good to excellent both by patients and families and the craniofacial team. CONCLUSION: Le Fort III DO with a rigid external distraction device in patients with Crouzon syndrome is a powerful and reliable surgical procedure that reliably produces a more significant change of appearance than most other single procedures routinely performed by craniofacial surgeons. It effectively treated sleep apnea in the affected patients. In our collective, the maxilla remained stable after advancement without any relapse, but there was no subsequent anterior growth on one year follow-up. Careful vector planning was able to avoid frontal open bite in eight patients. Complication rates were acceptably low and patients' functional and esthetic outcome was high.

Impact of severity and therapy onset on helmet therapy in positional plagiocephaly.

Although helmet therapy is a widely established method in the treatment of positional plagiocephaly, therapeutic regimens remain contentious, especially regarding starting age. Hence, this study investigated the impact of starting age and severity on the effectiveness of helmet therapy. A total of 213 pediatric patients treated for positional plagiocephaly with an orthotic device were enrolled in this study. Pre- and post-treatment calvarial asymmetry was measured according to the Cranial Vault Asymmetry Index (CVAI) using 3D-Photogrammetry. Patients were classified by age at which treatment was started: Group 1 was comprised of patients younger than 24 weeks (n = 82); Group 2, those aged 24-32 weeks (n = 75); Group 3, those aged >32 weeks (n = 56). Additionally, groups were categorized by severity (mild: CVAI 3-7%; moderate: CVAI 7-12%; severe: CVAI > 12%). Mean initial CVAI was 9.8%, which reduced to 5.4% after helmet treatment. Group 1 (<24 weeks) showed the highest absolute and relative rate of correction. Within the groups, severity correlated positively with relative and absolute reduction of the asymmetry. A significant difference in the reduction of the CVAI depending on age was only seen in moderate and severe cases of plagiocephaly- but not in mild plagiocephaly. The present study confirms the effectiveness of helmet therapy for positional plagiocephaly. The use of an orthotic device is an appropriate treatment option particularly in infants with severe plagiocephaly and a start of helmet therapy before the age of 6 month is advisable.

Approach to intraoperative electromagnetic navigation in orthognathic surgery: A phantom skull based trial.

INTRODUCTION: Intraoperative guidance using electromagnetic navigation is an upcoming method in maxillofacial surgery. However, due to their unwieldy structures, especially the line-of-sight problem, optical navigation devices are not used for daily orthognathic surgery. Therefore, orthognathic surgery was simulated on study phantom skulls, evaluating the accuracy and handling of a new electromagnetic tracking system. MATERIAL AND METHODS: Le-Fort I osteotomies were performed on 10 plastic skulls. Orthognathic surgical planning was done in the conventional way using plaster models. Accuracy of the gold standard, splint-based model surgery versus an electromagnetic tracking system was evaluated by measuring the actual maxillary deviation using bimaxillary splints and preoperative and postoperative cone beam computer tomography imaging. The distance of five anatomical marker points were compared pre- and postoperatively. RESULTS: The electromagnetic tracking system was significantly more accurate in all measured parameters compared with the gold standard using bimaxillary splints (p < 0.01). The data shows a discrepancy between the model surgical plans and the actual correction of the upper jaw of 0.8 mm. Using the electromagnetic tracking, we could reduce the discrepancy of the maxillary transposition between the planned and actual orthognathic surgery to 0.3 mm on average. DISCUSSION: The data of this preliminary study shows a high level of accuracy in surgical orthognathic performance using electromagnetic navigation, and may offer greater precision than the conventional plaster model surgery with bimaxillary splints. CONCLUSION: This preliminary work shows great potential for the establishment of an intraoperative electromagnetic navigation system for maxillofacial surgery.