Biomechanical assessment of mandibular fracture fixation using finite element analysis validated by polymeric mandible mechanical testing.

The clinical finite element analysis (FEA) application in maxillofacial surgery for mandibular fracture is limited due to the lack of a validated FEA model. Therefore, this study aims to develop a validated FEA model for mandibular fracture treatment, by assessing non-comminuted mandibular fracture fixation. FEA models were created for mandibles with single simple symphysis, parasymphysis, and angle fractures; fixated with 2.0 mm 4-hole titanium miniplates located at three different configurations with clinically known differences in stability, namely: superior border, inferior border, and two plate combinations. The FEA models were validated with series of Synbone polymeric mandible mechanical testing (PMMT) using a mechanical test bench with an identical test set-up. The first outcome was that the current understanding of stable simple mandibular fracture fixation was reproducible in both the FEA and PMMT. Optimal fracture stability was achieved with the two plate combination, followed by superior border, and then inferior border plating. Second, the FEA and the PMMT findings were consistent and comparable (a total displacement difference of 1.13 mm). In conclusion, the FEA and the PMMT outcomes were similar, and hence suitable for simple mandibular fracture treatment analyses. The FEA model can possibly be applied for non-routine complex mandibular fracture management.

Maxillofacial haemorrhagic symptoms in emergency department patients: impact of antithrombotics.

PURPOSE: To investigate the effect of antithrombotics on the occurrence of maxillofacial haemorrhagic symptoms, and to determine if these haemorrhagic symptoms are predictors of maxillofacial fractures. METHOD: A prospective cohort study was conducted of consecutive patients with maxillofacial trauma who had been admitted to the emergency department of four hospitals in the Netherlands. This study compared five haemorrhagic symptoms (peri-orbital haematoma, raccoon eyes, epistaxis, subconjunctival ecchymosis, and intra-oral haematoma) between patients not-using (NUA) and using (UA) of antithrombotics, and whether these maxillofacial haemorrhagic symptoms served as predictors for maxillofacial fractures. RESULTS: Out of the 1005 patients, 812 (81%) belonged to the NUA group, and 193 (19%) to the UA group. UA patients exhibited higher frequencies of peri-orbital hematoma (54% vs. 39%, p < 0.001), raccoon eyes (10% vs. 5%, p = 0.01), and subconjunctival ecchymoses (16% vs. 7%, p < 0.001). In NUA, peri-orbital hematoma (OR = 2.5, p < 0.001), epistaxis (OR = 4.1, p < 0.001), subconjunctival ecchymosis (OR = 2.3, p = 0.02), and intra-oral hematoma (OR = 7.1, p < 0.001) were significant fracture predictors. Among UA, peri-orbital hematoma (OR = 2.2, p = 0.04), epistaxis (OR = 5.4, p < 0.001), subconjunctival ecchymosis (OR = 3.7, p = 0.008), and intra-oral hematoma (OR = 22.0, p < 0.001) were significant fracture predictors. CONCLUSION: Maxillofacial haemorrhagic symptoms were observed more frequently in the UA group than in the NUA group. However, in both groups, maxillofacial haemorrhagic symptoms appear to be predictors of maxillofacial fractures. Caution is warranted in attributing these symptoms solely to antithrombotic use during emergency department assessments.

Quantitative Three-Dimensional Computed Tomography Measurements Provide a Precise Diagnosis of Fractures of the Mandibular Condylar Process.

As 2D quantitative measurements are often insufficient, a standardized 3D quantitative measurement method was developed to analyze mandibular condylar fractures, and correlate the results with the mandibular condylar fracture classifications of Loukota and Spiessl and Schroll and clinical parameters. Thirty-two patients with a unilateral mandibular condylar fracture were evaluated using OPT, 2D (CB)CT images, and 3D imaging to measure the extent of the fractures. The maximum mouth opening (MMO) was measured. Ramus height loss could be measured only in OPT, but not in 2D CT images. The Intraclass Correlation Coefficient was excellent in the 3D measurements. In the Loukota classification, condylar neck fractures had the largest median 3D displacement and the highest rotations of the fracture fragments. The largest fracture volume was observed in base fractures. According to the Spiessl and Schroll classification, type V fractures had the largest median 3D displacement and the highest rotation in the X-axis and Z-axis. Type I fractures had the largest fracture volume. We found a moderate negative correlation between MMO and 3D displacement and rotation on Z-axis. The 2D quantitative analysis of condylar fractures is limited, imprecise, and not reproducible, while quantitative 3D measurements provide extensive, precise, objective, and reproducible information.

Reliability and accuracy of the torque applied to osteosynthesis screws by maxillofacial surgeons and residents.

Applying the right torque to osteosynthesis screws is important for undisturbed bone healing. This study aimed to compare test-retest and intra-individual reliabilities of the torque applied to 1.5 mm and 2.0 mm osteosynthesis screws by residents and oral and maxillofacial surgeons (OMF-surgeons), to define the reference torque intervals, and to compare reference torque interval compliances. Five experienced OMF-surgeons and 20 residents, 5 of each 4 residency years, were included. Each participant inserted six 1.5 × 4 mm and six 2.0 × 6 mm screws into a preclinical model at two test moments 2 weeks apart (T1 and T2). Participants were blinded for the applied torque. Descriptive statistics, reference intervals, and intra-class correlation coefficients (ICC) were calculated. The OMF-surgeons complied more to the reference intervals (1.5 mm screws: 95% and 2.0 mm screws: 100%) than the residents (82% and 90%, respectively; P = 0.009 and P = 0.007) with the ICCs ranging between 0.85-0.95 and 0.45-0.97, respectively. The residents' accuracy and reliability were inadequate regarding the 1.5 mm screws but both measures improved at T2 for both screw types compared to T1, indicating a learning effect. Training residents and/or verifying the applied torque by experienced OMF-surgeons remains necessary to achieve high accuracy and reliability, particularly for 1.5 mm screws.

Titanium or Biodegradable Osteosynthesis in Maxillofacial Surgery? In Vitro and In Vivo Performances.

Osteosynthesis systems are used to fixate bone segments in maxillofacial surgery. Titanium osteosynthesis systems are currently the gold standard. However, the disadvantages result in symptomatic removal in up to 40% of cases. Biodegradable osteosynthesis systems, composed of degradable polymers, could reduce the need for removal of osteosynthesis systems while avoiding the aforementioned disadvantages of titanium osteosyntheses. However, disadvantages of biodegradable systems include decreased mechanical properties and possible foreign body reactions. In this review, the literature that focused on the in vitro and in vivo performances of biodegradable and titanium osteosyntheses is discussed. The focus was on factors underlying the favorable clinical outcome of osteosyntheses, including the degradation characteristics of biodegradable osteosyntheses and the host response they elicit. Furthermore, recommendations for clinical usage and future research are given. Based on the available (clinical) evidence, biodegradable copolymeric osteosyntheses are a viable alternative to titanium osteosyntheses when applied to treat maxillofacial trauma, with similar efficacy and significantly lower symptomatic osteosynthesis removal. For orthognathic surgery, biodegradable copolymeric osteosyntheses are a valid alternative to titanium osteosyntheses, but a longer operation time is needed. An osteosynthesis system composed of an amorphous copolymer, preferably using ultrasound welding with well-contoured shapes and sufficient mechanical properties, has the greatest potential as a biocompatible biodegradable copolymeric osteosynthesis system. Future research should focus on surface modifications (e.g., nanogel coatings) and novel biodegradable materials (e.g., magnesium alloys and silk) to address the disadvantages of current osteosynthesis systems.

Outcome of implants placed to retain craniofacial prostheses - A retrospective cohort study with a follow-up of up to 30 years.

OBJECTIVES: To retrospectively assess the treatment outcomes of endosseous implants placed to retain craniofacial prostheses. MATERIAL AND METHODS: Patients with craniofacial defects resulting from congenital disease, trauma, or oncologic treatment had implant retained prostheses placed in the mastoid, orbital, or nasal region and then assessed over a period of up to 30 years. Implant survival rates were calculated with the Kaplan-Meier method. Clinical assessments consisted of scoring skin reactions under the prosthesis and the peri-implant skin reactions. Possible risk factors for implant loss were identified. Patient satisfaction was evaluated using a 10-point VAS-scale. RESULTS: A total of 525 implants placed in 201 patients were included. The median follow up was 71 months (IQR 28-174 months). Implants placed in the mastoid and nasal region showed the highest overall implant survival rates (10-year implant survival rates of 93.7% and 92.5%, respectively), while the orbital implants had the lowest overall survival rate (84.2%). Radiotherapy was a significant risk factor for implant loss (HR 3.14, p < 0.001). No differences in implant loss were found between pre- and post-operative radiotherapy (p = 0.89). Soft tissue problems were not frequently encountered, and the patients were highly satisfied with their implant-retained prosthesis. CONCLUSION: Implants used to retain craniofacial prostheses have high survival and patient satisfaction rates and can thus be considered as a predictable treatment option. Radiation is the most important risk factor for implant loss.

Maxillofacial Fractures in Electric and Conventional Bicycle-Related Accidents.

PURPOSE: With the increased use of both e-bike and conventional bicycle, the number of bicycle-related accidents has increased accordingly. To determine whether there are differences in maxillofacial injuries between these 2 types of bicycle accidents, e-bike and conventional bicycle accidents were compared. MATERIAL AND METHODS: A retrospective cohort study was conducted for all the consecutive patients with maxillofacial injury due to e-bike and conventional bicycle accidents attending the emergency department of 4 hospitals in the Netherlands between May 2018 and October 2019. Primary outcomes are maxillofacial fractures present or absent and the severity of maxillofacial injury using the Maximum Abbreviated Injury Scale and Facial Injury Severity Scale (FISS) after e-bike and conventional bicycle accidents. A binary logistic regression analysis was used to assess differences in risk between an e-bike and conventional bicycle accident, where age, alcohol use, and comorbidities were added as covariates, for maxillofacial fractures, dental injury, and severe maxillofacial fractures. RESULTS: In total, 311 patients were included (73 e-bikers and 238 conventional cyclists). Sex distribution was equal in both groups (45% male vs 55% female). The e-bike group was older (66 vs 53 median age in years, P < .001) and had more comorbidities (0 vs 1, P < .001), while alcohol use was higher in the conventional bicycle group (32% vs 16%, P = .008). e-Bikers sustained midfacial fractures more frequently (47% vs 34%, P = .04), whereas conventional cyclists more often had mandibular fractures (1% vs 11%, P = .01). Although median Maximum Abbreviated Injury Scale and FISS scores did not differ between e-bike and conventional bicycle accidents, severe maxillofacial fractures (FISS score ≥ 2) were observed more often in the conventional cyclists (45% vs 25%, P = .04). No significant differences in risk of midfacial, mandibular, and severe maxillofacial fractures were found between e-bikers and conventional cyclists irrespective of their age, alcohol use, and comorbidities. CONCLUSION: Both the distribution and the severe maxillofacial fractures differed between the e-bike and conventional bicycle accident patients. Patient-specific characteristics, such as age, alcohol use, and comorbidities, may have a greater influence on sustaining maxillofacial fractures than the type of bicycle ridden.

A clinical decision aid for patients with suspected midfacial and mandibular fractures (the REDUCTION-I study): a prospective multicentre cohort study.

PURPOSE: To assess physical examination findings related to maxillofacial trauma to identify patients at risk of midfacial and mandibular fractures and then to construct a clinical decision aid to rule out the presence of midfacial and mandibular fractures in emergency department patients. METHODS: We performed a prospective multicentre cohort study in four hospitals in the Netherlands, including consecutive patients with maxillofacial trauma. Each patient received a standardized physical examination consisting of 15 and 14 findings for midfacial and mandibular traumas, respectively. Consequently, clinical decision aids were constructed with the focus being on ruling out the presence of midfacial and mandibular fractures, and diagnostic accuracy was calculated. RESULTS: A total of 993 consecutive patients were identified of whom 766 and 280 patients were suspected of midfacial and mandibular fractures, respectively. Midfacial fractures were diagnosed in 339 patients (44.3%), whereas mandibular fractures were observed in 66 patients (23.6%). The decision aid for midfacial trauma consisting of peri-orbital hematoma, epistaxis, ocular movement limitation, infra-orbital nerve paresthesia, palpable step-off and tooth mobility or avulsion, produced a sensitivity of 89.7 (86.0-92.5), a specificity of 42.6 (38.0-47.4), and a negative predictive value of 83.9% (78.4-88.2). The decision aid for mandibular trauma consisting of the angular compression test, axial chin pressure test, objective malocclusion, tooth mobility or avulsion and the tongue blade bite test resulted in a sensitivity of 98.5 (91.9-99.7), a specificity of 34.6 (28.5-41.2), and a negative predictive value of 98.7% (92.8-99.8). CONCLUSION: The constructed clinical decision aids for maxillofacial trauma may aid in stratifying patients suspected for midfacial and mandibular fractures to reduce unnecessary diagnostic imaging. CLINICAL TRIAL REGISTRATION: The study was registered at ClinicalTrials.gov with the identifier NCT03314480.

Biocompatibility and degradation comparisons of four biodegradable copolymeric osteosynthesis systems used in maxillofacial surgery: A goat model with four years follow-up.

Applying biodegradable osteosyntheses avoids the disadvantages of titanium osteosyntheses. However, foreign-body reactions remain a major concern and evidence of complete resorption is lacking. This study compared the physico-chemical properties, histological response and radiographs of four copolymeric biodegradable osteosynthesis systems in a goat model with 48-months follow-up. The systems were implanted subperiosteally in both tibia and radius of 12 Dutch White goats. The BioSorb FX [poly(70LLA-co-30DLLA)], Inion CPS [poly([70-78.5]LLA-co-[16-24]DLLA-co-4TMC)], SonicWeld Rx [poly(DLLA)], LactoSorb [poly(82LLA-co-18GA)] systems and a negative control were randomly implanted in each extremity. Samples were assessed at 6-, 12-, 18-, 24-, 36-, and 48-month follow-up. Surface topography was performed using scanning electron microscopy (SEM). Differential scanning calorimetry and gel permeation chromatography were performed on initial and explanted samples. Histological sections were systematically assessed by two blinded researchers using (polarized) light microscopy, SEM and energy-dispersive X-ray analysis. The SonicWeld Rx system was amorphous while the others were semi-crystalline. Foreign-body reactions were not observed during the complete follow-up. The SonicWeld Rx and LactoSorb systems reached bone percentages of negative controls after 18 months while the BioSorb Fx and Inion CPS systems reached these levels after 36 months. The SonicWeld Rx system showed the most predictable degradation profile. All the biodegradable systems were safe to use and well-tolerated (i.e., complete implant replacement by bone, no clinical or histological foreign body reactions, no [sterile] abscess formation, no re-interventions needed), but nanoscale residual polymeric fragments were observed at every system's assessment.

Diagnostic accuracy of physical examination findings for midfacial fractures: a systematic review and meta-analysis.

OBJECTIVES: To conduct a systematic review and meta-analysis to assess the diagnostic accuracy of physical examination findings and related clinical decision aids for midfacial fractures in comparison to computed tomography and cone beam computed tomography. MATERIAL AND METHODS: A systematic review was performed by searching the MEDLINE, Cochrane, EMBASE, and CINAHL databases. Risk of bias was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. Pooled sensitivity, specificity, and diagnostic odds ratios with the corresponding 95% confidence intervals were calculated for each physical examination finding and reported clinical decision aids. RESULTS: After screening 2367 records, 12 studies were included. High risk of patient selection bias was detected in three studies (25%). Additionally, high concerns regarding applicability were found for the patient selection in five studies (41.7%), and for the reference standard in eleven studies (91.7%). Of the total 42 individual physical examination findings, only 31 were suitable for a meta-analysis. High specificity and low sensitivity were found for most findings. The pooled diagnostic odds ratio ranged from 1.07 to 11.38. Clinical decision aids were reported by 8 studies, but none were constructed specifically for midfacial fractures. CONCLUSION: Based on the current available evidence, the absence of physical examination findings can successfully identify patients who do not have a midfacial fracture, but the presence of individual findings does not necessarily mean that the patient has a midfacial fracture. Although various clinical decision aids were presented, none focused on exclusively midfacial fractures. CLINICAL RELEVANCE: The diagnostic accuracy of physical examination findings can be used to diagnose a midfacial fracture so as to reduce unnecessary imaging, health care costs, and exposure to ionizing radiation.

A clinical decision aid to discern patients without and with midfacial and mandibular fractures that require treatment (the REDUCTION-II study): a prospective multicentre cohort study.

PURPOSE: To assess the diagnostic accuracy of physical examination findings and to construct clinical decision aids to discern emergency department patients without and with midfacial and mandibular fractures that require treatment. METHODS: A prospective multicentre cohort study was conducted in four hospitals in the Netherlands. Consecutive maxillofacial trauma patients were included whereupon each patient underwent a standardized physical examination consisting of 15 and 14 findings for midfacial and mandibular trauma, respectively. The primary outcome was the decision whether to treat during the emergency department stay or within 24 h of admission. The diagnostic accuracy was calculated for the individual physical examination findings and ensuing clinical decision aids with the focus being on detecting midfacial and mandibular fractures that require active treatment. RESULTS: A total of 766 midfacial trauma patients were identified of whom 339 (44.3%) had midfacial fractures. Of those, 74 (21.8%) required active treatment. A total of 280 mandibular trauma patients were identified of whom 66 (23.6%) had mandibular fractures. Of those, 37 (56.0%) required active treatment. The decision aid for midfacial trauma consisting of facial depression, epistaxis, ocular movement limitation, palpable step-off, objective malocclusion and tooth mobility or avulsion had a sensitivity of 97.3 (90.7-99.3), a specificity of 38.6 (35.0-42.3), and a negative predictive value of 99.3 (97.3-99.8). The decision aid for mandibular trauma consisting of mouth opening limitation, jaw movement pain, objective malocclusion and tooth mobility or avulsion resulted in a sensitivity of 100.0 (90.6-100.0), a specificity of 39.1 (33.2-45.4), and a negative predictive value of 100.0 (96.1-100.0). CONCLUSION: The clinical decision aids successfully identified midfacial and mandibular trauma patients requiring active fracture treatment and so may be useful in preventing unnecessary radiological procedures in the future. TRIAL REGISTRATION: The study was registered at ClinicalTrials.gov with the identifier NCT03314480.

Structural similarity analysis of midfacial fractures-a feasibility study.

The structural similarity index metric is used to measure the similarity between two images. The aim here was to study the feasibility of this metric to measure the structural similarity and fracture characteristics of midfacial fractures in computed tomography (CT) datasets following radiation dose reduction, iterative reconstruction (IR) and deep learning reconstruction. Zygomaticomaxillary fractures were inflicted on four human cadaver specimen and scanned with standard and low dose CT protocols. Datasets were reconstructed using varying strengths of IR and the subsequently applying the PixelShine™ deep learning algorithm as post processing. Individual small and non-dislocated fractures were selected for the data analysis. After attenuating the osseous anatomy of interest, registration was performed to superimpose the datasets and subsequently to measure by structural image quality. Changes to the fracture characteristics were measured by comparing each fracture to the mirrored contralateral anatomy. Twelve fracture locations were included in the data analysis. The most structural image quality changes occurred with radiation dose reduction (0.980036±0.011904), whilst the effects of IR strength (0.995399±0.001059) and the deep learning algorithm (0.999996±0.000002) were small. Radiation dose reduction and IR strength tended to affect the fracture characteristics. Both the structural image quality and fracture characteristics were not affected by the use of the deep learning algorithm. In conclusion, evidence is provided for the feasibility of using the structural similarity index metric for the analysis of structural image quality and fracture characteristics.

Efficacy and morbidity of biodegradable versus titanium osteosyntheses in orthognathic surgery: A systematic review with meta-analysis and trial sequential analysis.

Titanium osteosynthesis is currently the gold standard in orthognathic surgery. Use of biodegradable osteosyntheses avoids removal of plates/screws in a second operation. This systematic review aimed to assess the efficacy and morbidity of biodegradable vs. titanium osteosyntheses in orthognathic surgery (PROSPERO CRD42018086477). Patients with syndromic disorder(s) and/or cleft lip/palate were excluded. Randomised, prospective and retrospective controlled studies were searched for in nine databases (February 2021). The time periods perioperative, short-term, intermediate, long-term, and overall follow-up were studied. Meta-analyses were performed using random-effects models. A total of 9073 records was assessed, of which 33 were included, comprising 2551 patients. Seven RCTs had 'some concerns' while another seven RCTs had 'high' risk of bias (Cochrane-RoB2). No differences in malunion (qualitative analyses), mobility of bone segments [RR 1.37 (0.47; 3.99)], and malocclusion [RR 0.93 (0.39; 2.26)] were found. The operative time was longer in the biodegradable group [SMD 0.50 (0.09; 0.91)]. Symptomatic plate/screw removal was comparable among both groups [RR 1.29 (0.68; 2.44)]. Skeletal stability was similar in most types of surgery. Biodegradable osteosyntheses is a valid alternative to titanium osteosyntheses for orthognathic surgery, but with longer operation times. Since the quality of evidence varied from very low to moderate, high-quality research is necessary to elucidate the potential of biodegradable osteosyntheses.

Diagnostic accuracy of physical examination findings for midfacial and mandibular fractures.

OBJECTIVES: To assess the diagnostic accuracy of physical examination findings used to identify patients at risk for midfacial or mandibular fractures. MATERIALS AND METHODS: A five-year retrospective cohort was constructed from all emergency department patients with a midfacial or mandibular trauma. The sensitivity, specificity, pre-test probability, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio data was calculated for 19 and 14 physical examination findings for midfacial and mandibular fractures respectively. Computed Tomography and panoramic radiography were used as index tests. RESULTS: A total of 1484 patients were identified among whom 40.4% midfacial and 33.4% mandibular fractures were diagnosed. Overall, specificity was found to be higher than sensitivity. Regarding midfacial fractures, high specificity was found for raccoon eyes, malar eminence flattening and all the findings that are related to palpation, the nasal, ocular and intra-oral assessment. Malar eminence flattening, external nasal deformity, nasal septum hematoma, change of globe position and palpable step-off had ad high positive predictive value and positive likelihood ratio. Regarding mandibular fractures high specificity was found for mouth opening restriction, auditory canal bleeding, intra-oral assessment related findings, palpable step-off, inferior alveolar nerve paresthesia, the angular compression test and chin axial pressure test. CONCLUSIONS: The diagnostic accuracy of relevant physical examination findings were identified for the prediction of midfacial and mandibular fractures.

Iterative reconstruction and deep learning algorithms for enabling low-dose computed tomography in midfacial trauma.

OBJECTIVES: The objective of this study was to quantitatively assess the image quality of Advanced Modeled Iterative Reconstruction (ADMIRE) and the PixelShine (PS) deep learning algorithm for the optimization of low-dose computed tomography protocols in midfacial trauma. STUDY DESIGN: Six fresh frozen human cadaver head specimens were scanned by computed tomography using both standard and low-dose scan protocols. Three iterative reconstruction strengths were applied to reconstruct bone and soft tissue data sets and these were subsequently applied to the PS algorithm. Signal-to-noise ratios (SNRs) and contrast-to-noise ratios (CNRs) were calculated for each data set by using the image noise measurements of 10 consecutive image slices from a standardized region of interest template. RESULTS: The low-dose scan protocol resulted in a 61.7% decrease in the radiation dose. Radiation dose reduction significantly reduced, and iterative reconstruction and the deep learning algorithm significantly improved, the CNR for bone and soft tissue data sets. The algorithms improved image quality after substantial dose reduction. The greatest improvement in SNRs and CNRs was found using the iterative reconstruction algorithm. CONCLUSION: Both the ADMIRE and PS algorithms significantly improved image quality after substantial radiation dose reduction.

Comparison of the mechanical properties of biodegradable and titanium osteosynthesis systems used in oral and maxillofacial surgery.

To guide the selection of osteosynthesis systems, this study compared the mechanical properties of biodegradable and titanium osteosynthesis systems. SonicPins Rx and xG were subjected to pull-out tests. Additionally, 15 biodegradable (Inion CPS 2.0 and 2.5 mm; LactoSorb 2.0 mm; Macropore 2.0 mm; Polymax 2.0 mm; BioSorb FX 2.0 mm; ResorbX 2.1 mm; Osteotrans-MX 2.0 mm with plate thicknesses 1.0 and 1.4 mm; SonicWeld Rxplate/Rxpins, xGplate/Rxpins and xGplate/xGpins 2.1 mm without and with tapping the burr hole) and six titanium (CrossDrive (2006), CrossDrive (2018), MaxDrive; all 1.5 and 2.0 mm) straight, four-hole osteosynthesis systems were evaluated. All systems were subjected to tensile, bending and torsion tests. Pull-out loads of the SonicPins were comparable (P = 0.423). Titanium systems' tensile loads were higher than biodegradable systems (P < 0.001). CrossDrive (2018) and MaxDrive systems' tensile and torsional stiffness were lower, accompanied with higher ductility, than corresponding CrossDrive (2006) systems (P < 0.001). Bending stiffness of 1.5 mm titanium systems was comparable to, and of the 2.0 mm systems higher than, all biodegradable systems (P < 0.001). Regarding biodegradable systems, Inion CPS 2.5 mm had highest tensile load and torsional stiffness, SonicWeld 2.1 mm highest tensile stiffness, and BioSorbFX 2.0 mm highest bending stiffness (P < 0.001). On the basis of the results of this study, the CrossDrive (2018) and MaxDrive 1.5 mm titanium systems are recommended for midface fractures (e.g., zygomatic or maxillary fractures) and osteotomies (e.g., Le Fort I osteotomy), and the CrossDrive (2018) and MaxDrive 2.0 mm titanium systems for mandibular fractures and osteotomies when a titanium osteosynthesis system is used. When there is an indication for a biodegradable osteosynthesis system, the SonicWeld 2.1 mm or BioSorbFX 2.0 mm are recommended for midface fractures and osteotomies, and the Inion CPS 2.5 mm biodegradable system for mandibular osteotomies and non-load bearing mandibular fractures, especially when high torsional forces are expected (e.g., mandibular symphysis fractures).

Novel finite element-based plate design for bridging mandibular defects: Reducing mechanical failure.

INTRODUCTION: When the application of a free vascularised flap is not possible, a segmental mandibular defect is often reconstructed using a conventional reconstruction plate. Mechanical failure of such reconstructions is mostly caused by plate fracture and screw pull-out. This study aims to develop a reliable, mechanically superior, yet slender patient-specific reconstruction plate that reduces failure due to these causes. PATIENTS AND METHODS: Eight patients were included in the study. Indications were as follows: fractured reconstruction plate (2), loosened screws (1) and primary reconstruction of a mandibular continuity defect (5). Failed conventional reconstructions were studied using finite element analysis (FEA). A 3D virtual surgical plan (3D-VSP) with a novel patient-specific (PS) titanium plate was developed for each patient. Postoperative CBCT scanning was performed to validate reconstruction accuracy. RESULTS: All PS plates were placed accurately according to the 3D-VSP. Mean 3D screw entry point deviation was 1.54 mm (SD: 0.85, R: 0.10-3.19), and mean screw angular deviation was 5.76° (SD: 3.27, R: 1.26-16.62). FEA indicated decreased stress and screw pull-out inducing forces. No mechanical failures appeared (mean follow-up: 16 months, R: 7-29). CONCLUSION: Reconstructing mandibular continuity defects with bookshelf-reconstruction plates with FEA underpinning the design seems to reduce the risk of screw pull-out and plate fractures.

Accuracy and outcome of mandibular fracture reduction without and with an aid of a repositioning forceps.

PURPOSE: It is presumed that adequate reduction of a fracture of the mandible favors bone healing and diminishes the risk of complications. In this retrospective study, we compared the accuracy of fracture alignment and complication rate of mandibular fractures reduced without or with aid of a repositioning forceps. METHODS: Retrospective analysis of consecutive 252 patients with mandibular fractures treated between January 2010 and December 2016. Eligible for this study were patients with isolated mandibular fractures needing open reduction and internal fixation in whom pre- and postoperative radiographs and patient records were available. In total, 131 (252 fractures) patients fulfilled the inclusion criteria. RESULTS: Seventy-one (54%) patients were men. Mean age of the patients was 33 ± 16.5 years, and the median and interquartile range of age was 25 (20;41). In 54 patients, mandibular fractures were reduced without the aid of repositioning forceps, and in the remaining 77 patients, the fractures were reduced with the aid of the repositioning forceps. Anatomical alignment of the fractures was poor in the non-forceps-aided group (48%) compared to the forceps-aided group (58%) (P = .067). Overall complication rate was higher in the group of fractures reduced without the aid of forceps (17%) than in the forceps-aided group (7%) (P = .045; OR, 2.7; 95% CI, 1.0-7.4). CONCLUSIONS: Mandibular fractures reduced with the aid of repositioning forceps are accompanied by a lower complication rate and better alignment. This is an important observation as better alignment of the fracture fragments favors bone healing and reduces complications.

Fractures of the mandibular condyle: A comparison of patients, fractures and treatment characteristics between Groningen (The Netherlands) and Dresden (Germany).

PURPOSE: To explore differences in patient, fracture, accident and treatment characteristics between patients treated for a mandibular condyle fracture in the University Centres of Dresden and Groningen, as an explanation for differences treatment results. MATERIALS AND METHODS: Patients' fracture, accident and treatment characteristics were obtained from the medical records of Dresden and Groningen from January 1, 2008, to August 31, 2011, and were analysed using logistic regression analysis. RESULTS: In Dresden, compared to Groningen, patients were generally older (OR 1.03, 95% CI 1.02; 1.05, per year), were more often male (OR 2.54, 95% CI 1.48; 4.34) and more often had intracapsular (OR 2.95, 95% CI 1.67; 5.22) and low condylar (OR 1.86, 95% CI 1.14; 3.04) fractures. In Groningen 98% of patients received closed treatment and in Dresden 42%. CONCLUSION: Significant differences in patients and fractures and treatments were found between both Centres. These differences can partly be explained by the demographics of the cities and differences in imaging techniques (e.g., computed tomography, Orthopantomogram, Towne projection) applied to identify fractures. This study illustrates that differences in diagnosis, treatment and outcome are not only related to the health care system but also to differences in patient characteristics between centres.

A Treatment Protocol for Fractures of the Edentulous Mandible.

PURPOSE: The incidence of fractures of edentulous mandibles is relatively low. Knowledge about the management of these fractured edentulous mandibles relies heavily on case reports and observational studies. On the basis of the current literature, we compiled a treatment protocol for fractures of the edentulous mandible and hypothesized that this protocol would result in fewer complications. PATIENTS AND METHODS: We conducted a retrospective cohort study of edentulous patients with mandibular fractures. The predictor variable was the fulfillment of the treatment protocol (yes or no). The outcome variables were postoperative complications and reoperations. Patient demographic characteristics were collected from patient records. The χ2 test was used for statistical analysis between predictor and outcome variables. RESULTS: Of 61 edentulous mandibular fractures (36 patients), 53 were treated according to the protocol and 8 were not. We observed 4 complications in the first group (complication rate, 7.5% [4 of 53]) and 4 in the second group (complication rate, 50% [4 of 8]). The fracture treatments that followed the protocol had a significantly lower postoperative complication rate (P = .001; odds ratio, 0.082) and needed fewer reoperations (P = .0001; odds ratio, 0.019) compared with the treatments that did not follow the protocol. CONCLUSIONS: The results of this study show that following the compiled treatment protocol for fractures of edentulous mandibles significantly reduces postoperative complications and reoperations.