Three dimensional versus standard miniplate fixation in management of mandibular fractures: A systematic review and meta-analysis

Classification of unusual fracture patterns of the mandible: A retrospective study

The aim of this study is to devise and summarize a classification of fracture patterns involving multiple anatomical sites of the mandible. A retrospective study was conducted by reviewing clinical case records, imaging records, and the surgical management of patients presenting with mandibular fracture. Demographic data were collected and causes of the fractures were studied. Following radiological evaluations based on the courses of fracture lines, these fractures were categorized into three components: horizontal (H), vertical (V), and sagittal (S). In case of horizontal components, the mandibular canal was used as a reference. For vertical components, the fracture lines were classified according to where they terminated. With sagittal components, the direction of the bicortical split at the base of mandible was used as a reference. Out of a total of 893 mandibular trauma patients, 30 unusual fractures were identified (21 in males and nine in females), which do not fit into existing classifications. These were mainly due to road traffic accidents. Horizontal components of fractures were classified as H-I, H-II, and H-III, and vertical components as V-I, V-II, and V-III. For sagittal components, two types were identified - S-I and S-II - resulting in a bicortical split of the mandible. This classification is proposed to help understanding the complex fractures and to allow standardized communication among clinicians. Moreover, it is designed in such a way that aids in the choice of fixation technique. Further studies are needed to establish standardized treatment algorithms for efficient management of these unusual fractures.

An In Vitro Evaluation of a Novel Design Z Plate for Fixation of Mandibular Symphysis and Parasymphysis Fractures-A Finite Element Analysis

Aim

Surgical management of mandibular symphysis and parasymphysis fractures has evolved from rigid fixation to semi-rigid fixation with miniplate osteosynthesis. Various miniplate systems have been developed in recent years including three-dimensional miniplate, microplates and bioresorbable plate, and their advantages and disadvantages have been compared and studied. To overcome the shortcomings of 3D plating system such as difficulty in adaptation and fixation in fractures involving the mental nerve, a novel Z plate has been designed by our institute.

Material and Methodology

An in vitro study was performed to evaluate the biomechanical behaviour of the newly designed Z plate with 3D plate and two-miniplate system using finite element analysis.

Results

Our study showed total structural deformation of 0.17 mm and 0.31 mm of newly designed Z plate after canine loading and molar loading, respectively. The equivalent von Mises force for plate after canine loading had shown the following results-Z plate showed values of 121.3 MPa and 58.40 MPa after molar loading.

Conclusion

Our study concluded that the Z plate produces lowest stresses, lesser total structural deformation, superior stability and support in comparison with the 3D plate and two-miniplate system.

Benefit-risk appraisal of lip-split mandibular "swing" vs. transoral approaches to posterior oral/oropharyngeal carcinomas using number needed to treat, to harm, and likelihood to be helped or harmed

PURPOSE

s: To evaluate benefit-risk profiles of lip-split mandibular "swing" vs. transoral approaches (LS-MSA; TOA) to the American Joint Committee on Cancer (AJCC) stage I-III posterior oral/oropharyngeal carcinomas (PO/OPC).

METHODS

Using a retrospective double-cohort study design, we enrolled stage I-III PO/OPC patients treated in two German medical centers during a 4-year interval. The predictor variable was surgical technique (LS-MSA/TOA), and main outcomes were complete resection with R₀ margins (CR-R₀), 5-year overall survival and recurrence (OS₅; R₅), and adverse events (AEs). Descriptive and bivariate statistics were computed with α = 95%. Benefit-risk profiles were investigated using number needed to treat (NNT), to harm (NNH), and likelihood to be helped or harmed (LLH).

RESULTS

At 5-year follow-ups of 202 subjects, LS-MSA caused significantly better CR-R₀ (P = 0.001; NNT: 4) and fewer R₅ (P = 0.003; NNT: 5), but more risks of wound dehiscence ([WD]; P = 0.01; NNH = 8), and orocutaneous fistula ([OCF]; P = 0.01; NNH: 10). LLH calculations demonstrated that LS-MSA was 2 and 1.6 times more likely to result in CR-R₀ and fewer R₅ than an incident of WD. There was no significant difference in OS₅, postoperative infections (within 30 postoperative days) and AE domains according to the University of Washington Quality of Life questionnaire version 4 (UW-QoLv4) between the surgical approach groups.

CONCLUSIONS

Compared to TOA, LS-MSA is an efficacious and tolerable intervention for inspecting and eradicating stage I-III PO/OPCs, and reducing recurrences at 5-year follow-ups. Post-LS-MSA WD and OCF require meticulous concerns and more investigations.

Evaluation of condylar position in anterior mandibular fractures using 3 dimensional miniplate osteosynthesis versus conventional miniplates: Randomized clinical trial

To compare clinically and radiographically between the 3-D plates and the conventional two Champy's miniplates in the treatment of anterior mandibular fractures. It is a randomized clinical and radiographic comparative study between 2 equal groups of patients with isolated anterior mandibular fractures. Open reduction and internal rigid fixation was accomplished in the study group using 3D miniplates fixation while in the control group using the two Champy's miniplates. The 3D miniplate osteosynthesis consumed less operative time than the two miniplates osteosynthesis. Independent t-test revealed that the difference between the 2 groups was 8.4 ± 3.11 min. This difference was statistically significant (p=0.012). Occlusion was slightly disturbed in two patients in the study group in comparison to three patients in the control group. The difference between the 2 groups was not statistically significant (p=0.62). None of the cases of both groups showed mobility between the reduced and fixed fractured segments, immediately post-operatively and at the end of follow-up intervals. The 3D miniplate osteosynthesis (study group) recorded less intercondylar distance than two miniplates osteosynthesis (control group) immediately post-operatively and after 3 months. Independent t-test revealed that the difference between the 2 groups was not statistically significant, immediately postoperative (p=0.322) and after 3 months (p=0.263). Pre-operatively to 3 months postoperatively, the 3D miniplate osteosynthesis (study group) recorded a lower median percent increase in the intercondylar distance than the two miniplates osteosynthesis (control group). The difference between the 2 groups was not statistically significant (p=0.917). Regarding the intercondylar angle, the3D miniplate osteosynthesis (study group) recorded higher intercondylar angle than the two miniplates osteosynthesis (control group) immediately post-operative (p=0.333) and after 3 months (p=0.255). Independent t-test revealed that the difference between the 2 groups was not statistically significant. The 3-Dimensional strut miniplates should be considered an alternative for internal rigid fixation of anterior mandibular fractures for their ease of adaptation and insertion, while providing the advantage of reduced operative time compared to the conventional two Champy's miniplates.

Treatment of Mandible Fractures Using a Miniplate System: A Retrospective Analysis

Three-dimensional (3D) mini plate systems are used in the treatment of mandibular fractures. The system is advantageous in comparison to conventional plates due to the stabilization of tension and compression areas, improved initial stability, and biomechanical behavior. The aim of this retrospective study was to evaluate the use of a 3D miniplate system for the treatment of patients with mandibular fractures. Patients with mandibular fractures treated with a 3D plate system at the Department of Oral and Maxillofacial Surgery, University Hospital Münster, during a period of 5 years, were included in this study. Mandibular fracture conditions and minor and major post-operative complications were reported. In total, 336 patients and 391 mandibular fractures were assessed. The most common fracture site was anterior mandible, and 155 cases involved a tooth-bearing area. Minor complications were seen in 8.03% of cases, whereas only 1.49% of patients suffered from major complications. The treatment of mandible fractures using 3D miniplates resulted in fracture reduction with a low complication rate.

Assessment of biomechanical properties of specially-designed miniplate patterns in a mandibular subcondylar fracture model with finite element analysis and a servohydraulic testing unit

The aim of our study was to compare the biomechanical stability of three different systems used to fix mandibular condylar fractures on synthetic polyurethane mandibles using a servohydraulic testing unit and finite element analysis (FEA). We measured the resistance to displacement loads causing 1.75 and 3.5mm displacements of the fragments, and the maximum resistance values before failure of the fixation system in 30 condylar necks of 15 polyurethane mandible models. The three subgroups investigated were arranged as a triangular plate (n=10), a quadrangular plate (n=10), and a straight miniplate (n=10). The most successful fixation pattern was achieved with two straight four-hole miniplates. However, the triangular plate can easily be applied as a second option by an endoscopic approach. The rectangular plates showed no success in mandibular condylar fractures.

Evaluation of a Vertical Box Plating Technique for Mandibular Body Fractures and Retrospective Analysis of Patient Outcomes

Importance

Despite advancements, treatment of mandibular body fractures is plagued by complications. Evaluation of a new plating system is needed with the goal of reducing complication rates.

Objectives

To evaluate the biomechanical behavior of a vertically oriented box plate vs traditional rigid internal fixation plating techniques for mandibular body fractures and to test if placement of the 3-dimensional plate oriented parallel to the fracture line provides improved rigidity and greater resistance to torsion, resulting in improved outcomes.

Design, Setting, and Participants

A mandible fracture model with synthetic replicas was used to compare resistance to torsional forces of different plating configurations. Additionally, a retrospective comparative review of the medical records of 84 patients with mandibular body fractures treated from 2005 to 2018 at Jacobi Medical Center, a level-1 trauma hospital in Bronx, New York, was completed.

Exposures

Patients sustained a mandibular body fracture and were treated with open reduction and internal fixation using metal plating.

Main Outcomes and Measures

In the comparative study of biomechanical behavior of various plating configurations, maximum torque sustained prior to deformation and loss of alignment was measured. Medical records were reviewed for surgical approach, plating techniques, operative time, length of admission, and rate of complications, including malocclusion, nonunion, infection, neurosensory disturbance, and wound dehiscence.

Results

Of the 84 patients included in the retrospective review, 76 (91%) were men, and the mean (SD) age was 29.7 (12.0) years. During biomechanical analysis, the vertical box plate provided greater stability and 150% of the resistance against torsional forces when compared with traditional linear plating. In the retrospective review, analysis showed vertical plating was associated with a lower incidence of postoperative neurosensory disturbance (25 [38%] patients treated with vertical plating vs 0 patients treated with box plating; P = .002) and a lower risk of any complication (41 [62%] vs 6 [33%], respectively; relative risk, 0.54; 95% CI, 0.27-1.06; P = .03). Vertical plating was associated with reduced operative time (134 minutes vs 70 minutes, respectively; P < .001).

Conclusions and Relevance

This investigation suggests that vertical box plating is associated with a lower incidence of postoperative complications and reduced operative time compared with traditional plating techniques. The comparative biomechanical component demonstrated that the vertical box plate offered equal or greater resistance to torsional forces. Further studies of greater power and level of evidence are needed to more robustly demonstrate these benefits.

Level of Evidence

3.

A customized fixation plate with novel structure designed by topological optimization for mandibular angle fracture based on finite element analysis

Background

The purpose of this study was to design a customized fixation plate for mandibular angle fracture using topological optimization based on the biomechanical properties of the two conventional fixation systems, and compare the results of stress, strain and displacement distributions calculated by finite element analysis (FEA).

Methods

A three-dimensional (3D) virtual mandible was reconstructed from CT images with a mimic angle fracture and a 1 mm gap between two bone segments, and then a FEA model, including volume mesh with inhomogeneous bone material properties, three loading conditions and constraints (muscles and condyles), was created to design a customized plate using topological optimization method, then the shape of the plate was referenced from the stress concentrated area on an initial part created from thickened bone surface for optimal calculation, and then the plate was formulated as “V” pattern according to dimensions of standard mini-plate finally. To compare the biomechanical behavior of the “V” plate and other conventional mini-plates for angle fracture fixation, two conventional fixation systems were used: type A, one standard mini-plate, and type B, two standard mini-plates, and the stress, strain and displacement distributions within the three fixation systems were compared and discussed.

Results

The stress, strain and displacement distributions to the angle fractured mandible with three different fixation modalities were collected, respectively, and the maximum stress for each model emerged at the mandibular ramus or screw holes. Under the same loading conditions, the maximum stress on the customized fixation system decreased 74.3, 75.6 and 70.6% compared to type A, and 34.9, 34.1, and 39.6% compared to type B. All maximum von Mises stresses of mandible were well below the allowable stress of human bone, as well as maximum principal strain. And the displacement diagram of bony segments indicated the effect of treatment with different fixation systems.

Conclusions

The customized fixation system with topological optimized structure has good biomechanical behavior for mandibular angle fracture because the stress, strain and displacement within the plate could be reduced significantly comparing to conventional “one mini-plate” or “two mini-plates” systems. The design methodology for customized fixation system could be used for other fractures in mandible or other bones to acquire better mechanical behavior of the system and improve stable environment for bone healing. And together with SLM, the customized plate with optimal structure could be designed and fabricated rapidly to satisfy the urgent time requirements for treatment.