Open Reduction and Internal Fixation of Unilateral Mandibular Condylar Base and Neck Fractures Using a Lambda Plate: Selection Criteria for Application.

PURPOSE: The aim of this study was to evaluate the clinical, radiologic, and functional outcomes in a retrospective cohort study of patients with condylar base and neck fractures treated with open reduction and internal fixation via lambda plates to define selection criteria for their application. PATIENTS AND METHODS: Eleven patients underwent open reduction and internal fixation using lambda plates for osteosynthesis of condylar base and neck fractures. The mean follow-up period was 8 months. All kinds of complications were recorded. Postoperative maximum jaw opening and occlusion were determined. Pain on palpation of the joint area, pain on movement, and muscle pain were examined. The criteria for the intraoperative selection of a lambda plate were recorded. RESULTS: Positioning and fixation of lambda plates were feasible in all cases. A condylar neck fracture with limited bone surface on the proximal fragment for internal fixation prevailed as the primary indication for the selection of a lambda plate. Avoiding extensive soft tissue stripping at the proximal fragment when using a transoral endoscopically assisted approach in cases of condylar base fractures also was a selection criterion. The overall complication rate was low. CONCLUSIONS: The indications for lambda plates for internal fixation of condylar fractures are neck fractures with limited bone surface along the proximal fragment for internal fixation. Application of the plate through a transoral endoscopic approach to avoid extensive soft tissue stripping at the proximal fragment is favorable in high condylar base fractures.

Combination of Rigid and Nonrigid Fixation Versus Nonrigid Fixation for Bilateral Mandibular Fractures: A Multicenter Randomized Controlled Trial.

PURPOSE: We aimed to compare complication rates and functional outcomes in patients with bilateral mandibular fractures treated with different degrees of internal fixation rigidity. PATIENTS AND METHODS: This international, multicenter randomized controlled trial included adults with bilateral mandibular fractures located at either the angle and body, angle and symphysis, or body and symphysis. Patients were treated with either a combination of rigid fixation for the anterior fracture and nonrigid fixation for the posterior fracture (mixed fixation) or nonrigid fixation for both fractures. The primary outcome was complications within 6 weeks after surgery. Secondary outcomes were complications within 3 months, Helkimo dysfunction index, and mandibular mobility at 6 weeks and 3 months after surgery. RESULTS: Of the 315 patients enrolled, 158 were randomized to the mixed fixation group and 157 to the nonrigid fixation group. The overall complication rate at 6 weeks in the intention-to-treat population was 9.6% (95% confidence interval [CI], 5.3% to 15.6%) in the mixed fixation group and 7.8% (95% CI, 4.0% to 13.5%) in the nonrigid fixation group. With an unadjusted odds ratio of 1.25 (95% CI, 0.51 to 3.17), there were no statistically significant differences in complication rates between the 2 groups (P = .591). A multivariable model for complication risk at 6 weeks found no significant differences between treatment groups, but patients with moderate or severe displacement had a higher complication rate than those with no or minimal displacement (adjusted odds ratio, 4.58; 95% CI, 1.16 to 18.06; P = .030). There were no significant between-group differences in complication rates at 3 months. Moreover, no significant differences in Helkimo dysfunction index and mandibular mobility index at 6 weeks and 3 months were found between groups according to treatment allocated and treatment received. CONCLUSIONS: A combination of rigid and nonrigid fixation in patients with bilateral mandibular fracture has similar complication rates and functional outcomes to nonrigid fixation for both fractures.

MRI of the inferior alveolar nerve and lingual nerve-anatomical variation and morphometric benchmark values of nerve diameters in healthy subjects.

OBJECTIVE: Since MRI using dedicated imaging sequences has recently shown promising results in direct visualization of the inferior alveolar nerve (IAN) and the lingual nerve (LN) with high spatial resolution, the aim of this study was to generate suitable standard specifications to reliably depict the IAN and LN in MRI and to delineate the anatomy and its variants of these nerves in healthy subjects. METHODS: Thirty healthy volunteers were examined on a 3-T scanner (Elition, Philips Healthcare, Best, the Netherlands). The sequence protocol consisted of 3D STIR, 3D DESS, and 3D T1 FFE "black bone" sequences. RESULTS: The study reconfirmed a good feasibility of direct visualization of proximal and peripheral portions of the IAN and of the proximal course of the LN. The STIR sequence showed the highest apparent signal to noise ratio (aSNR) and best apparent nerve-muscle contrast to noise ratio (aNMCNR) for IAN and for the LN. The applied MRI sequences allowed to differentiate the tissue composition of the neurovascular bundle inside the mandibular canal. CONCLUSION: Dedicated MRI sequence protocols proved effectively to detect the IAN and LN and their course in healthy volunteers. The tissue composition of the mandibular neurovascular bundle was conclusively distinguishable as was the varying topography inside multiple bony channels. CLINICAL RELEVANCE: The presented data on the precise and valid visualization of the IAN and LN have clinical implications in respect to local anesthesia prior to dental treatments in the mandible but also regarding surgical procedures and implant insertion in the molar region.

Evaluation of Complications After Open Reduction and Internal Fixation of Mandibular Condylar Base and Neck Fractures Using Trapezoidal Plates.

The purpose of the study was to evaluate the different fracture pattern of patients being treated with trapezoidal plate fixation of condylar base and neck fractures using the AOCMF Classification System to determine specific fracture pattern that are associated with failure of trapezoidal plate fixation. Ten patients with mandibular condylar base and neck fractures underwent internal fixation using trapezoidal plates. Fractures of the condylar process were classified according to the AOCMF Classification System using computed tomography data. The fracture pattern was compared to complications according to hardware failure such as plate or screw loosening and plate fracture. Plate and screw loosening of trapezoidal plates for fixation of condylar base and neck fractures was associated with fracture location in the neck region and major fragment displacement with contact loss between the proximal and distal fragment of the fracture. Further investigations such as finite-element analysis of different plating systems for fixation of condylar neck fractures are necessary to establish the optimal fixation technique for condylar neck fractures.

Open Reduction and Internal Fixation of Mandibular Condylar Base and Neck Fractures Using Strut Plates.

PURPOSE: To evaluate clinical, radiologic, and functional outcomes of patients with condylar neck or base fractures treated with open reduction and internal fixation using strut plates. PATIENTS AND METHODS: Thirty patients with 34 condylar neck and base fractures were included in the study. Transoral endoscopically assisted, submandibular, or transparotid approaches were performed. Clinical and radiologic outcomes were evaluated. Functional outcomes were assessed with the Helkimo index in a subgroup of 15 patients. RESULTS: Strut plates were successfully placed in all surgical approaches used in this study. Fracture healing occurred without complications in 33 condylar processes. One plate fracture occurred. In the subgroup, 7 patients had a good functional outcome, 7 had a slightly impaired functional outcome, and 1 patient had a moderately impaired functional outcome. CONCLUSION: Strut plates are appropriate for retromandibular transparotid, endoscopically assisted transoral, or submandibular approaches in the management of condylar neck or base fractures. Intraoperative handling and fitting accuracy of the strut plates are good. Good to slightly impaired functional outcome was observed in a subgroup of patients.

Computer-Assisted Designed and Manufactured Procedures Facilitate the Lingual Application of Mandible Reconstruction Plates.

PURPOSE: Lingual positioning of mandible reconstruction plates can prevent typical complications such as plate exposure and orocutaneous fistulas. The aim of this study was to evaluate the feasibility and clinical outcomes of lingually applied patient-specific reconstruction plates. MATERIALS AND METHODS: A retrospective cohort study of patients managed with reconstruction plates positioned at the lingual side of the mandible was performed. The following outcome variables were analyzed: feasibility and handling of the lingual application, fitting accuracy, and postoperative complications. RESULTS: The study sample included 8 patients (4 women, 4 men) with a mean age of 68.8 years (range, 43 to 79 yr). The indications for plate use were defect-like zones owing to multiple fractures in the atrophic mandible (n = 2) and segmental defects attributed to squamous cell carcinoma, osteomyelitis, and bisphosphonate-related osteonecrosis (n = 6). Off-the-shelf reconstruction plates, which were intraoperatively bent (n = 2) or pre-bent to a stereolithographic model (n = 1), or fully computer-assisted designed and computer-assisted manufactured (CAD/CAM) patient-specific reconstruction plates (n = 5) were used. Lingual application of reconstruction plates was feasible in all cases and considerably facilitated by the CAD/CAM plates. The fitting accuracy was high. Within an average follow-up period of 15.3 months, no loosening of plates or screws, plate fracture, or orocutaneous fistula occurred and no dysphagia was observed with the exception of 1 case, in which plate exposure was due to extreme soft tissue thinning and tumor recurrence. CONCLUSIONS: Lingual application of CAD/CAM patient-specific reconstruction plates is technically feasible with high accuracy. It has great potential for low complication rates, especially in unfavorable soft tissue conditions.

Maxillofacial Fractures: Midface and Internal Orbit-Part I: Classification and Assessment.

Fractures of the midface and internal orbit occur isolated or in combination with other injuries. Frequently, the patients are first seen in emergency rooms responsible for the coordination of initial diagnostic procedures, followed by the transfer to specialties for further treatment. It is, therefore, important for all physicians treating facial trauma patients to understand the basic principles of injuries to the midface. Thus, this article aims to describe the anatomy and the current classification systems in use, the related clinical symptoms, and the essential diagnostic measures to obtain precise information about the injury pattern.

Maxillofacial Fractures: Midface and Internal Orbit-Part II: Principles and Surgical Treatment.

Current clinical assessment and imaging techniques were described in part 1, and this article presents a systematic review of the surgical treatment principles in the management of midface and internal orbit fractures from initial care to definitive treatment, including illustrative case examples. New developments enabled limited surgical approaches by standardization of osteosynthesis principles regarding three-dimensional buttress reconstruction, by newly developed individualized implants such as titanium meshes and, especially for complex fracture patterns, by critical assessment of anatomical reconstruction through intraoperative endoscopy, as well as intra- and postoperative imaging. Resorbable soft tissue anchors can be used both for ligament and soft tissue resuspension to reduce ptosis effects in the cheeks and nasolabial area and to achieve facial aesthetics similar to those prior to the injury.

The orbits--anatomical features in view of innovative surgical methods.

The aim of this article is to update on anatomical key elements of the orbits in reference to surgical innovations. This is a selective literature review supplemented with the personal experience of the authors, using illustrations and photographs of anatomical dissections. The seven osseous components of the orbit can be conceptualized into a simple geometrical layout of a four-sided pyramid with the anterior aditus as a base and the posterior cone as apex. All neurovascular structures pass through bony openings in the sphenoid bone before diversification in the mid and anterior orbit. A set of landmarks such as the optic and maxillary strut comes into new focus. Within the topographical surfaces of the internal orbit the lazy S-shaped floor and the posteromedial bulge are principal determinants for the ocular globe position. The inferomedial orbital strut represents a discernible sagittal buttress. The periorbita and orbital soft tissue contents--extraocular muscles, septae, neurovasculature--are detailed and put into context with periorbital dissection.

Orbital reconstruction: prefabricated implants, data transfer, and revision surgery.

External impact to the orbit may cause a blowout or zygomatico-maxillary fractures. Diagnosis and treatment of orbital wall fractures are based on both physical examination and computed tomography scan of the orbit. Injuries of the orbit often require a reconstruction of its orbital walls. Using computer-assisted techniques, anatomically preformed orbital implants, and intraoperative imaging offers precise and predictable results of orbital reconstructions. Secondary reconstruction of the orbital cavity is challenging due to fractures healed in malposition, defects, scarring, and lack of anatomic landmarks, and should be avoided by precise primary reconstruction. The development of preformed orbital implants based on topographical analysis of the orbital cavity was a milestone for the improvement of primary orbital reconstruction.

Transoral open reduction and fixation of mandibular condylar base and neck fractures in children and young teenagers--a beneficial treatment option?

PURPOSE: To evaluate the possible benefits of open surgery, endoscopically assisted reduction and fixation using a transoral route was used in a selected series of pediatric patients with displaced condylar base and neck fractures. PATIENTS AND METHODS: A cohort of 6 patients (1 male and 5 female; age range, 7 to 15 yr; mean, 13.4 yr) with displaced condylar base and neck fractures (n = 9) were included. Inclusion criteria were age younger than 16 years, fracture of the condylar base or neck, and displacement of the fracture by at least 45°. Fractures were classified using conventional radiography, cone-beam computed tomography, or computed tomography. Patients underwent transoral endoscopically assisted open reduction and fixation using miniplate osteosynthesis. Postoperatively, patients were followed clinically and radiographically for 18 months. RESULTS: Complete follow-up varied from 18 to 35 months (median, 24.5 months). All patients showed normal occlusion and pain-free unrestricted function of the temporomandibular joint at 3, 6, 12, and 18 months postoperatively. There were no signs of incomplete remodeling or deformation of the condyles. CONCLUSION: Transoral endoscopically assisted surgical treatment of severely displaced condylar base and neck fractures in children and young teenagers offers a reliable solution to preclude the sequelae of closed treatment, such as altered morphology and functional disturbances, eliminates visible scars, and lowers the risk of facial nerve damage compared with open reduction using an extraoral approach.

MatrixMANDIBLE preformed reconstruction plates--a two-year two-institution experience in 71 patients.

PURPOSE: To evaluate handling, complication rates, clinical and treatment outcomes of the MatrixMANDIBLE Preformed Reconstruction Plates (MMPRPs), in particular with regard to the frequency of fatigue fractures and operative time. PATIENTS AND METHODS: A cohort of 71 subjects with an indication for a load-bearing osteosynthesis of the mandible was enrolled in the present study. The indications for plate use were defects due to tumor, trauma, or osteonecrosis. The outcome variables were fitting accuracy, application time, and postoperative complications, defined as plate exposure, loosening of plates or screws, plate fracture, and orocutaneous fistulas. Additionally, the feasibility of a transoral approach was tested. RESULTS: The sample included 71 subjects with a mean age of 54.8 ± 15.0 years, including 43 men (60.6%). MMPRPs could be placed in 70 of the 71 patients. In 10 patients a transoral approach for plate application was successfully performed. The mean time investment to contour the plates was 13.1 minutes. The fitting accuracies of the nonbendable sections were satisfying. No plate fracture was observed within an average follow-up period of 11.8 months. Postoperative complications occurred in 19 (27.1%) of the 70 patients. Plate removal was required in 11 (15.7%) of 70 patients. CONCLUSIONS: The results of the present study suggest that the use of MMPRPs coincides with a reduced operative time and a minimized risk of fatigue fractures. Thus, MMPRPs seem to be a useful standard device in a scope of indications for load-bearing osteosynthesis of the anterolateral division of the mandible, additionally facilitating a transoral approach for application.

Digital planning and individual implants for secondary reconstruction of midfacial deformities: A pilot study.

Objective: To evaluate the feasibility and accuracy of implementing three-dimensional virtual surgical planning (VSP) and subsequent transfer by additive manufactured tools in the secondary reconstruction of residual post-traumatic deformities in the midface. Methods: Patients after secondary reconstruction of post-traumatic midfacial deformities were included in this case series. The metrical deviation between the virtually planned and postoperative position of patient-specific implants (PSI) and bone segments was measured at corresponding reference points. Further information collected included demographic data, post-traumatic symptoms, and type of transfer tools. Results: Eight consecutive patients were enrolled in the study. In five patients, VSP with subsequent manufacturing of combined predrilling/osteotomy guides and PSI was performed. In three patients, osteotomy guides, repositioning guides, and individually prebent plates were used following VSP. The median distances between the virtually planned and the postoperative position of the PSI were 2.01 mm (n = 18) compared to a median distance concerning the bone segments of 3.05 mm (n = 12). In patients where PSI were used, the median displacement of the bone segments was lower (n = 7, median 2.77 mm) than in the group with prebent plates (n = 5, 3.28 mm). Conclusion: This study demonstrated the feasibility of VSP and transfer by additive manufactured tools for the secondary reconstruction of complex residual post-traumatic deformities in the midface. However, the median deviations observed in this case series were unexpectedly high. The use of navigational systems may further improve the level of accuracy.

Accuracy of free-hand positioned patient specific implants (PSI) in primary reconstruction after inferior and/or medial orbital wall fractures.

BACKGROUND: To assess the accuracy with which CAD/CAM-fabricated patient-specific titanium implants (PSI) are positioned for inferior and/or medial orbital wall reconstruction without the use of intraoperative navigation. METHODS: Patients who underwent a primary reconstruction of the orbital walls with PSI due to fractures were enrolled in this retrospective cohort analysis. The primary outcome variables were the mean surface distances (MSD) between virtually planned and postoperative PSI position and single linear deviations in the x-, y- and z-axis at corresponding reference points. Secondary outcome variables included demographic data, classification of orbital wall defects and clinical outcomes. RESULTS: A total of 33 PSI (orbital floor n = 22; medial wall, n = 11) were examined in 27 patients. MSD was on a comparable level for the orbital floor and medial wall (median 0.39 mm, range 0.22-1.53 mm vs. median 0.42 mm, range 0.21-0.98 mm; p = 0.56). Single linear deviations were lower for reconstructions of the orbital floor compared to the medial wall (median 0.45 vs. 0.79 mm; p < 0.05). There was no association between the occurrence of diplopia and the accuracy level (p = 0.418). CONCLUSIONS: Free-hand positioning of PSI reaches a clinically appropriate level of accuracy, limiting the necessity of navigational systems to selected cases.

Analyzing the Fitting of Novel Preformed Osteosynthesis Plates for the Reduction and Fixation of Mandibular Fractures.

PURPOSE: The known preformed osteosynthesis plates for the midface are helpful tools for a precise and fast fixation of repositioned fractures. The purpose of the current study is to analyze the precision of newly developed prototypes of preformed osteosynthesis plates for the mandible. METHODS: Four newly designed preformed osteosynthesis plates, generated by a statistical shape model based on 115 CT scans, were virtually analyzed. The used plates were designed for symphyseal, parasymphyseal, angle, and condyle fractures. Each type of plate has three different sizes. For analysis, the shortest distance between the plate and the bone surface was measured, and the sum of the plate-to-bone distances over the whole surface was calculated. RESULTS: A distance between plate and bone of less than 1.5 mm was defined as sufficient fitting. The plate for symphyseal fractures showed good fitting in 90% of the cases for size M, and in 84% for size L. For parasymphyseal fractures, size S fits in 80%, size M in 68%, and size L in 65% of the cases. Angle fractures with their specific plate show good fitting for size S in 53%, size M in 60%, and size L in 47%. The preformed plate for the condyle part fits for size S in 75%, for size M in 85%, and for size L in 74% of the cases. CONCLUSION: The newly developed mandible plates show sufficient clinical fitting to ensure adequate fracture reduction and fixation.

Prediction of surface area size in orbital floor and medial orbital wall fractures based on topographical subregions.

OBJECTIVE: This retrospective study evaluates the occurrence and frequency of different fracture patterns in a series of computed tomography (CT) scans in terms of the AOCMF Trauma Classification (TC) orbit module and correlates the assigned defects with measurements of the fracture area in order to get an approximate guideline for fracture size predictions on the basis of the classification. MATERIAL AND METHODS: CT scans of patients with orbital floor fractures were evaluated using the AOCMFTC to determine the topographical subregions. The coding consisted of: W = orbital wall, 1 = anterior orbit, 2 = midorbit, i = inferior, m = medial. The 3-dimensional surface area size of the fractures was quantified by the "defect body" method (Brainlab, Munich, Germany). The fracture area size and its confidence and prediction interval within each topographical subregion was estimated by regression analysis. RESULTS: A total of 137 CT scans exhibited 145 orbital floor fractures, which were combined with 34 medial orbital wall fractures in 31 patients. The floor fractures - W1(i)2(i) (n = 86) and W1(i) (n = 19) were the most frequent patterns. Combined floor and medial wall fractures most frequently corresponded to the pattern W1 (im)2 (im) (n = 15) ahead of W1 (im) 2(i) (n = 10). The surface area size ranged from 0.11 cm2 to 6.09 cm2 for orbital floor and from 0.29 cm2 to 5.43 cm2 for medial wall fractures. The prediction values of the mean fracture area size within the subregions were computed as follows: W1(i) = 2.25 cm2, W2(i) = 1.64 cm2, W1(i)2(i) = 3.10 cm2, W1(m) = 1.36 cm2, W2(m) = 1.65 cm2, W1(m)2(m) = 2.98 cm2, W1 (im) = 3.35 cm2, W1 (im) 2(i) = 4.63 cm2, W1 (im)2(m) = 4.06 cm2 and W1 (im)2 (im) = 7.16 cm2. CONCLUSION: The AOCMFTC orbital module offers a suitable framework for topographical allocation of fracture patterns inside the infero-medial orbital cavity. The involvement of the subregions is of predictive value providing estimations of the mean 3-D fracture area size.

The Comprehensive AO CMF Classification System for Mandibular Fractures: A Multicenter Validation Study.

The AO CMF has recently launched the first comprehensive classification system for craniomaxillofacial (CMF) fractures. The AO CMF classification system uses a hierarchical framework with three levels of growing complexity (levels 1, 2, and 3). Level 1 of the system identifies the presence of fractures in four anatomic areas (mandible, midface, skull base, and cranial vault). Level 2 variables describe the location of the fractures within those defined areas. Level 3 variables describe details of fracture morphology such as fragmentation, displacement, and dislocation. This multiplanar radiographic image-based AO CMF trauma classification system is constantly evolving and beginning to enter worldwide application. A validation of the system is mandatory prior to a reliable communication and data processing in clinical and research environments. This interobserver reliability and accuracy study is aiming to validate the three current modules of the AO CMF classification system for mandible trauma in adults. To assess the performance of the system at the different precision levels, it focuses on the fracture location within the mandibular regions and condylar process subregions as core components giving only secondary attention to morphologic variables. A total of 15 subjects individually assigned the location and features of mandibular fractures in 200 CT scans using the AO CMF classification system. The results of these ratings were then statistically evaluated for interobserver reliability by Fleiss' kappa and accuracy by percentage agreement with an experienced reference assessor. The scores were used to determine if the variables of levels 2 and 3 were appropriate tools for valid classification. Interobserver reliability and accuracy were compared by hierarchy of variables (level 2 vs. level 3), by anatomical region and subregion, and by assessor experience level using Kruskal-Wallis and Wilcoxon's rank-sum tests. The AO CMF classification system was determined to be reliable and accurate for classifying mandibular fractures for most levels 2 and 3 variables. Level 2 variables had significantly higher interobserver reliability than level 3 variables (median kappa: 0.69 vs. 0.59, p < 0.001) as well as higher accuracy (median agreement: 94 vs. 91%, p < 0.001). Accuracy was adequate for most variables, but lower reliability was observed for condylar head fractures, fragmentation of condylar neck fractures, displacement types and direction of the condylar process overall, as well as the condylar neck and base fractures. Assessors with more clinical experience demonstrated higher reliability (median kappa high experience 0.66 vs. medium 0.59 vs. low 0.48, p < 0.001). Assessors with experience using the classification software also had higher reliability than their less experienced counterparts (median kappa: 0.76 vs. 0.57, p < 0.001). At present, the AO CMF classification system for mandibular fractures is suited for both clinical and research settings for level 2 variables. Accuracy and reliability decrease for level 3 variables specifically concerning fractures and displacement of condylar process fractures. This will require further investigation into why these fractures were characterized unreliably, which would guide modifications of the system and future instructions for its usage.

Virtual reconstruction of bilateral midfacial defects by using statistical shape modeling.

PURPOSE: Mirroring and manual adaptation as the main virtual reconstruction method of midfacial defects is time demanding and ignores asymmetrical skull shapes. By using a statistical shape model (SSM), the reconstruction can be automatized and specified. The current study aims to show the ability of the SSM in the virtual reconstruction of artificial bilateral defects. METHODS: Based on 131 pathologically unaffected CT scans of the adult midface region, an SSM was created. DICOM data were generated, segmented and registered on one mesh, which serves as template for the SSM. The SSM consists of the registered surface meshes and includes the shape variability of the cranial vault. Fractured or missing parts were calculated by the known shape variability of healthy midface data. Using 25 CT scans not included in the SSM, the precision of the reconstruction of virtually placed bilateral defects of the orbital floor (Group 1) and bilateral naso-orbital-ethmoid (NOE) fractures (Group 2). Distances to the corresponding parts of the intact skull were calculated to show the accuracy of the virtual reconstruction method. RESULTS: All defects could be reconstructed by using the SSM and GM technique. The analysis shows a high accuracy of the SSM-driven reconstruction, with a mean error of 0.75 ± 0.18 mm in group 1 and with a mean error of 0.81 ± 0.23 mm in group 2. CONCLUSION: The precision of the SSM-driven reconstruction is high and its application is easy for the clinician because of the automatization of the virtual reconstruction process in the field of computer-assisted surgery (CAS). Respecting of the natural asymmetry of the skull and the methods of GM are reasons for the high precision and the automatization of the new shown reconstruction workflow.

Analysis of the accuracy of a novel preformed osteosynthesis plate for the reduction and fixation of zygomaticomaxillary complex fractures.

INTRODUCTION: There has been a shift toward surgical treatment of ZMC (zygomaticomaxillary complex) fractures with open reduction and subsequent fixation in the past decades. Anatomically preformed osteosynthesis plates, already used in the field of craniomaxillofacial surgery for the treatment of fractures of the mandible and the orbit, might be a suitable option for ZMC fractures as well. MATERIAL AND METHODS: A statistical shape model was created from 179 cranial CT scans. Based on this surface model, an anatomically preformed plate for the reduction and fixation of ZMC fractures was developed in 3 sizes (S, M, L). Virtual analysis of the accuracy of the plate was performed on a dataset consisting of 120 CT scans. RESULTS: Within a determined tolerance range of 0-1.5 mm, analysis revealed a high accuracy of the plate in 70-87 % of the CT scans. The S-sized plate has the highest overall accuracy, whereas the L-sized plate has highest accuracy at the "base" region which is essential for the placement of the plate. DISCUSSION: The newly developed plate can be placed via an intraoral approach and analysis of the plate has confirmed its accuracy to be sufficient to ensure an adequate fracture reduction and fixation. It thus might allow for a less extensive approach and less approaches/incisions necessary overall to reduce and fixate ZMC fractures.