Development and biomechanical testing of a new osteosynthesis plate (TCP®) designed to stabilize mandibular condyle fractures

Influence of Method of Treatment of Mandibular Condylar Fractures on Range of Articular Path Measured by Cadiax Device

Background/Objectives: The aim of this study was to evaluate the function of the treated temporomandibular joint based on the analysis of the image of the articular path using the Cadiax device depending on the choice of treatment method for unilateral condylar fracture of the mandible. Methods: Sixty patients who were treated for condylar fractures of the mandible at the Maxil-lofacial Surgery Department in Katowice were qualified for the analysis of the range of movements of the mandibular heads using the Cadiax device. From the group of patients who suffered fractures of the mandible, including condylar processes, patients were finally qualified for the measurement of the articular path of the injured and healthy joint according to strict criteria. Results: The condylar examination was performed in 20 patients who had conservative condylar fracture treatment and 40 patients who underwent various surgeries in the course of a single condylar fracture. The control group consisted of 20 patients whose mean values for the articular pathway measured for both sides were 12.73 and 12.69 and fell within the standard developed for healthy joints tested with the Cadiax device. Conclusions: We have achieved an almost ideal treatment for condylar fractures. We are also beginning to notice the need for rehabilitation of patients after this type of surgery.

Application of the lambda plate on condylar fractures: Finite element evaluation of the fixation rigidity for different fracture patterns and plate placements

PURPOSE

The treatment challenges of condylar fractures necessitated the production of several plate designs. Among the relatively new plate designs is the lambda plate, for which biomechanical and clinical data are lacking. The purpose of this study is to examine the rigidity of fixation achieved when the lambda plate is applied to different fractures of the condylar neck and base.

METHODS

Five fractures of the condylar area were designed on a virtual model of a healthy mandible obtained from a CT scan. The fractures were reduced using the lambda plate. For the same fractures, alternative placements of the plate were simulated. The generated models were analysed using the finite element analysis for a 500 N bite load. The displacement of the two condylar fragments along the fracture line was calculated as an indicator of the rigidity of the fixation.

RESULTS

The displacement along the fracture was less than 0.144 mm for the neck fractures and greater than 0.165 mm for the fractures of the condylar base. A more cranial placement of the plate for the neck fractures further reduced the displacement, while a more anterior placement of the plate for the base fractures resulted in displacements greater than 0.330 mm.

CONCLUSION

According to our study, the lambda plate offers better rigidity when applied as cranially as possible for condylar neck fractures. The lambda plate did not provide adequate fixation for base fractures. A second plate at the sigmoid notch should be considered to achieve better stabilization along the fracture if the lambda plate is eventually used.

Reliability of a Trapezium Miniplate with Endoscope-Assisted Internal Fixation in Mandibular Subcondylar Fractures: A Three-Dimensional Analysis

This study aimed to evaluate the reliability of a trapezium plate for open reduction and internal fixation (ORIF) of mandibular subcondylar fractures with the simultaneous use of an endoscope. We selected and retrospectively studied 18 patients (12 males and 6 females) with unilateral mandibular subcondylar fractures who visited the Wonju Severance Christian Hospital. The mean age of the patients was 43.43 ± 15.76 years. Patients underwent ORIF with trapezium miniplate application through an intraoral incision under general anesthesia. The clinical and radiographic findings of the fractured side were compared with those of the non-operated side at 6 months follow-up. All occlusions became stable, and transient functional disturbances disappeared within 6 months of periodic follow-up. Functional mandibular movement recovered within the normal range, with an average mouth opening of 41.5 mm, protrusion of 7.5 mm, and lateral excursion of 7 mm at 6 months. Radiographic controls and statistical analysis confirmed a decent anatomical reduction in all 18 cases. In conclusion, the use of a trapezium miniplate with endoscope-assisted ORIF in mandibular subcondylar fractures can be useful for fixation and functional recovery.

Finite element analysis of different titanium miniplates: Evaluation of three-dimensional designs applied on condylar neck fractures

INTRODUCTION

The fixation of condylar neck fractures is raising difficulties and for this reason, many plate designs have been developed. The current study compares the performance of four miniplates used in the condylar neck.

MATERIAL AND METHODS

A virtual condylar neck fracture in a mandible obtained from a CT scan was fixed with four miniplates (two straight miniplates, lambda, strut, and trapezoidal). Using finite element analysis, we examined the fragments' displacements and stress distribution in the titanium material and bone. The models were analyzed under two loading conditions: a reduced bite force of 135 N and a force of 500 N.

RESULTS

No risk of material failure was observed. For a load of 135 N, all four plates offer an adequate fixation. For 500 N of applied loading, the lambda and strut plates showed the best rigidity and lowest bone strains. The two parallel plates showed the lowest rigidity and the trapezoidal plate the highest bone strains around all screws.

DISCUSSION

These findings imply that three-dimensional miniplates (lambda, strut) perform better when higher loads are applied. On the other hand, the trapezoidal plate has an increased risk of screw loosening and the two straight plates higher mobility of the fragments.

Three-Dimensional Osteosynthesis Plates for the Surgical Treatment of Mandibular Fractures

OBJECTIVES

Mandible fractures can be treated with different plate systems, that is, miniplates or three-dimensional (3D) plates. This systematic review describes the effectiveness and clinical outcomes of 3D plates used in fractures of the mandible and aims to critically evaluate its risks and benefits.

MATERIALS AND METHODS

A comprehensive electronic search was conducted without date but with restriction to articles written in English. Studies in humans, including randomized or quasi-randomized controlled trials and retrospective studies, were included. The outcome parameters measured were number of patients, fracture classification, results, follow-up period, postoperative complications, and mean age of patients. Major complications were defined as those needing additional surgical intervention, for example, malocclusion, infection or plate fracture. Accordingly, complications not needing additional surgical intervention were defined as minor (ie, dehiscence, trismus).

RESULTS

Guided by the PRISMA statement and the Cochrane Handbook for Systematic Reviews of Interventions, the authors identified 44 publications with a total of 1790 patients. Among the articles selected for the final review, there were 32 reported prospective studies, 12 reported retrospective studies. Regarding the evaluation of quality, 8 studies showed a low value of the risk of bias, 17 a moderate risk, and 19 a high risk. There were statistically significant advantages for 3D plates in mandibular fractures in terms of postoperative complications, for example, wound dehiscences or plate fracture.

CONCLUSIONS

The 3D plate is an effective treatment modality for mandibular fractures, with low incidence of major complications, decreased length of operation time, and increased stability of osteosynthesis.

Experimental validation of finite element simulation of a new custom-designed fixation plate to treat mandibular angle fracture

BACKGROUND

The objective of the study was to validate biomechanical characteristics of a 3D-printed, novel-designated fixation plate for treating mandibular angle fracture, and compare it with two commonly used fixation plates by finite element (FE) simulations and experimental testing.

METHODS

A 3D virtual mandible was created from a patient's CT images as the master model. A custom-designed plate and two commonly used fixation plates were reconstructed onto the master model for FE simulations. Modeling of angle fracture, simulation of muscles of mastication, and defining of boundary conditions were integrated into the theoretical model. Strain levels during different loading conditions were analyzed using a finite element method (FEM). For mechanical test design, samples of the virtual mandible with angle fracture and the custom-designed fixation plates were printed using selective laser sintering (SLS) and selective laser melting (SLM) printing methods. Experimental data were collected from a testing platform with attached strain gauges to the mandible and the plates at different 10 locations during mechanical tests. Simulation of muscle forces and temporomandibular joint conditions were built into the physical models to improve the accuracy of clinical conditions. The experimental vs the theoretical data collected at the 10 locations were compared, and the correlation coefficient was calculated.

RESULTS

The results show that use of the novel-designated fixation plate has significant mechanical advantages compared to the two commonly used fixation plates. The results of measured strains at each location show a very high correlation between the physical model and the virtual mandible of their biomechanical behaviors under simulated occlusal loading conditions when treating angle fracture of the mandible.

CONCLUSIONS

Based on the results from our study, we validate the accuracy of our computational model which allows us to use it for future clinical applications under more sophisticated biomechanical simulations and testing.

Does Three-Dimensional Plate Offer Better Outcome and Reduce the Surgical Time Following Open Reduction and Internal Fixation of Adult Mandibular Unilateral Subcondylar Fractures. A Randomized Clinical Study

PURPOSE

The management of the condyle fractures continue to be a source of perineal controversy in the field of oral and maxillofacial trauma. The aim of this study was to compare the surgical feasibility, functional outcome, and stability of fixation between the conventional miniplate and 3-dimensional plate in the management of adult mandibular unilateral subcondylar fractures.

MATERIALS AND METHODS

A prospective randomized clinical study with well-structured inclusion and exclusion criteria was carried out. Patients were allocated into Group A (Miniplates) and Group B (3-D Plates). The primary outcome variables were time taken for fixation, maximum mouth opening, occlusal stability, increase in angulation, and increase in the gap between fractured segments in the radiograph. The secondary outcome variables were needed for intermaxillary fixation (IMF) with guiding elastics and jaw movements. Statistical analysis was done using χ² test and student's t test with P value less than 0.05 indicating statistical significance.

RESULTS

Forty-four patients (40 male and 4 female) were enrolled, with 22 patients in each group. Time taken for fixation using 3-D plates was significantly lower than conventional miniplates (9.6 ± 0.9 minutes with P value 0.001). Although clinical parameters showed improved results for Group B, there was no statistical significance. Radiological parameters ie increase in angulation, and increase in the gap, showed statistically significant results. Group A had significant increases in the angulation of the fractured condyle at the end of the third and sixth months with a P value of 0.008 and 0.0001, respectively. The gap between the fractured segments was significantly increased in Group A at the end of the first and third months, with a P value of 0.022 and 0.003, respectively.

CONCLUSIONS

Our results concluded that 3-D plate offers superior fracture fragment stability and less displacement of the fractured segments. It has an added advantage of the ease of adaptation and shorter operating time.

Evaluation of Stress Distribution of Four Different Fixation Systems at High- and Low-Level Subcondylar Fractures on a Nonhomogenous Finite Element Model

PURPOSE

The aim of the present study was to provide insight into a suitable fixation system for subcondylar fractures located at different levels.

MATERIALS AND METHODS

High and low subcondylar fractures were simulated on a nonhomogenous mandibular model, and rhombic, trapezoid, and lambda plates and 2 miniplates were used for fixation. The stress in the bone and displacement of the fracture site were measured using finite element analysis.

RESULTS

For both high and low subcondylar fractures, the lowest von Mises stress was measured in the rhombic plate system. For high subcondylar fractures, the highest tension in the cortical bone was measured in the trapezoid plate system, and the highest compression was measured in the rhombic plate system. For low subcondylar fractures, the highest tension in the bone was measured in the rhombic system and the highest compression was measured in the trapezoid system. In both high and low subcondylar fracture models, the least displacement amount was measured in the 2-plate system.

CONCLUSIONS

The results of the present study have shown that the rhombic plate system might be the proper choice for high subcondylar fractures and the 2-plate system might provide better results for low subcondylar fractures.

Clinical experience and results with a Rhombic Plate for transoral endoscopically-assisted osteosynthesis of fractures of the condylar neck

The intraoral approach is favoured by many patients and surgeons for the treatment of fractures of the condylar neck, but the limited space offered by this approach can make positioning and fixation of the osteosynthesis plate difficult. A rhombic-shaped plate was designed specifically for use with the intraoral approach, and introduced into our clinical practice in 2012. We present the clinical and functional results in 81 patients with 98 fractures of the condylar neck who we have treated with this technique. Of these six required surgical revision, and ultimately all but two had satisfactory occlusion and mandibular function. Our complication rate of 6/81 (7.4%) compares favourably with those reported elsewhere, and confirms that open reduction and internal fixation of condylar fractures using the Rhombic plate through an intra-oral approach provides good outcomes.

Biomechanical behavior of mandibles reconstructed with fibular grafts at different vertical positions using finite element method

BACKGROUND

For large mandibular defects, surgical reconstruction using microvascular fibular grafts has advantages over other alternatives in terms of blood supply and good quality of grafted bone. However, the fibular segment is usually lower in height than that of the original mandible, meaning that the vertical positioning of the fibular graft is variable, with different biomechanical consequences on the reconstructed mandible.

OBJECTIVES

To use finite element method (FEM) to evaluate stress distribution and displacement of a reconstructed mandible versus an intact mandible under occlusal loads.

METHODS

A three-dimensional intact edentulous mandibular bone (Model I) and a reconstructed mandible bone with fibular graft were created from CBCT images. Calculation models were generated with fibular bone graft extracted from the reconstructed mandible of identical length placed into a mimicked defect area on the right-hand side of the mandible at three different vertical positions: superior (Model II), intermediate (Model III), and inferior (Model IV). Forces were applied at lower left first molar region and lower left central incisor area. Von Mises stresses and mandibular displacement were calculated as outcome measurements during loadings.

RESULTS

Maximum stress and strain within the reconstructed mandible were identified at the posterior border of the graft and the contralateral condyle. Maximum displacement occurred near the interface of fibular graft and anterior segment of the mandible. Stress distribution in the graft under functional loads is much higher than that in the residual mandibular segments from Models II to IV. The combined average maximum stress from anterior and posterior loads is 10.66 times higher in the mandible with inferiorly positioned graft (Model IV), 8.72 times for superior graft (Model II), and 3.68 times for intermediate graft (Model III) than that in the control group (Model I). The worst displacement result during functional loadings was in the group with fibular graft located at the inferior border of the mandible.

CONCLUSIONS

The position of fibular graft placed in the surgical resection site has significant effects on the mechanical behavior of the reconstructed mandible. The fibular graft aligned with the inferior border of the mandible, the most common site designated location by clinicians, has the worst effects on the stress distribution and displacement to the mandibular under functional loads. The fibular graft placed at the intermediate location has the best biomechanics and provides favorable condition for subsequent prosthetic reconstruction.

Does lag screw fixation of condylar fractures result in adequate stability? A finite element analysis

The great incidence and controversies related to the diagnosis, treatment, surgical accesses, and type of osteosynthesis materials confer an outstanding role to condylar fractures among facial fractures. Plate configurations, with diverse formats and sizes, may be used to surgically resolve condylar fractures. With the purpose of improving the advantages and minimizing the disadvantages of fixation techniques, the neck screw was developed aiming at the needed stabilization to render a correct fixation through a system of dynamic compression. This is achieved by increasing the contact between the fractured bone stumps, as well as assisting at the time of fracture reduction. The present paper aims at comparing the fixation and stability of mandibular condylar fractures using the neck screw and an overlaid "L"-shaped-4-hole-2 mm plate on the one hand, with a system in which the neck screw and the "L"-shaped plate form a single structure, having been joined by a welded point, on the other hand. The results with the neck screw are satisfactory, and, thus, it is an alternative for the reduction and fixation of fractures of the mandibular condyle, whether or not a plate is joined to the structure, provided it is correctly prescribed and with adequate surgical sequence and technique.

In-vitro comparison of mechanical resistance between two straight plates and a Y-plate for fixation of mandibular condyle fractures

OBJECTIVE

To compare the mechanical resistance of conventional plates with a modified Y-plate in mandibular condyle fracture.

MATERIALS AND METHODS

40 synthetic hemi-mandibular polyurethane replicates were used. Two groups of fixing materials were included: 20 mandibles fixed with 40 straight plates with four roles each (2.0 mm system) and 20 mandibles fixed with 20 Y-shaped plates (2.0 mm system and 1.5 mm thickness). The samples were submitted to linear loading in the following directions: 10 mandibles from each group from lateral to medial and 10 mandibles from each group from anterior to posterior. A universal loading machine, Instron Universal 4411, was used to performed the tests, and the resistance of each fixed mandible was assessed at displacements of 1 mm, 3 mm, and 5 mm. The t-test for independent samples was performed. The p value was set at <0.05.

RESULTS

The worst mechanical resistance was found in the Y-plates loaded from anterior to posterior. The best mechanical resistance was in two straight hole plates loaded from lateral to medial. The Y-plates and two straight hole plates showed similar resistance when a lateral to medial load was applied.

CONCLUSION

There was no difference between the plates when lateral to medial loading was tested.

Evaluation of an experimental oblique plate for osteosynthesis of mandibular condyle fractures

OBJECTIVE

The aim of this study was to test the bone thickness and potential screw length for osteosynthesis of condylar base fractures (according to the Loukota classification) with an experimental titanium plate, placed in an ideal position against 2 types of conventional plates.

STUDY DESIGN

After exclusion of completely edentulous mandibles, 28 dentate macerated mandibles available at the time of the study were included. Linear regression models 1 and 2 compared the sums of the 2 cranial bone thicknesses and the 3 caudal thicknesses among the 3 different plate designs, and linear models 3 and 4 tested the bone thickness in the 2 most cranial screw axes.

RESULTS

Linear models 1 and 2 revealed significantly higher potential screw lengths for the experimental oblique plate. Equally, linear models 3 and 4 indicated significantly higher bone thickness for the novel oblique plate.

CONCLUSION

The novel proposed oblique plate allows for favorable plate positioning in a biomechanically ideal location with sufficient amounts of local bone for stable plate fixation. When plates with 15-degree angulated screw holes are used, stable bicortical plate fixation can be achieved.

Does a Retromandibular Transparotid Approach for the Open Treatment of Condylar Fractures Result in Facial Nerve Injury?

PURPOSE

The retromandibular transparotid approach (RMA) to condylar fractures of the mandible provides excellent access, but can increase the risk of complications. The aim of this study was to estimate the frequency of facial nerve paralysis (FNP) and associated postoperative complications after open reduction and rigid internal fixation (ORIF) of subcondylar fractures through the RMA.

MATERIALS AND METHODS

This was a retrospective cohort study of patients with condylar fractures requiring ORIF through the RMA. The inclusion criteria were 1) a medical record of surgical treatment of a subcondylar fracture by RMA; 2) preoperative and postoperative radiographs; 3) mental status permitting an adequate neuromotor examination; 4) absence of a post-injury or pretreatment functional facial nerve deficit; and 5) regular postoperative follow-up longer than 6 months with documentation of complications, functional results, and fixation stability. The predictive variables were age, gender, fracture site, fracture pattern, concomitant fractures, etiology, and plate types. The outcome variable was FNP. Univariate, bivariate, and multiple logistic regression statistics were computed.

RESULTS

Fifty patients with 55 displaced mandibular subcondylar fractures (35 men, 15 women; mean age, 44.5 yr; range, 17 to 87 yr) met the inclusion criteria. The condylar fracture involved the neck in 35 patients (63.6%) and the base in 20 patients (36.4%). The fracture pattern was deviation in 11 patients (20.0%), displacement in 23 (41.8%), and dislocation in 21 (38.2%). Precise ORIF with double-buttress fixation resulted in immediate functional recovery in all patients. Seven fractures (12.7%) were associated with FNP that resolved completely within 6 months. Further statistical analysis showed that dislocated and displaced condylar neck fractures were significant risk factors for postoperative FNP (P < .05). Other postoperative complications were minimal.

CONCLUSION

The RMA for subcondylar fractures is feasible and safe. Dislocated condylar neck fractures are associated with a highly increased risk of temporary postoperative FNP as a surgical complication.

Evaluation of trapezoidal-shaped 3-D plates for internal fixation of mandibular subcondylar fractures in adults

AIMS

The purpose of this study is to evaluate the clinical results and to assess the efficacy, stability, and rigidity of trapezoidal 3-D plates for osteosynthesis in adult mandibular subcondylar fracture patients.

METHODS

This study included 15 cases of trauma having mandibular subcondylar fractures, in which open reduction and internal fixation are indicated. After selecting patient according to the inclusion criteria, all patients underwent open reduction and rigid fixation. Fracture was then stabilized using 4 hole, 2.0 mm trapezoidal-shaped 3-D titanium plates using retromandibular incision. Postoperative clinical examination was carried out on 3rd day; 1st, 2nd, and 4th weeks; and 3rd and 6th months.

RESULTS

The results of this study suggest that the fixation of mandibular subcondylar fracture with trapezoidal-shaped 3-D plates provides three-dimensional stability and carries low morbidity.

CONCLUSION

Patients with gross displacement of condylar fragment, major reduction in posterior facial height, and deranged occlusion can be successfully managed by open reduction of condylar fracture and its fixation using 3-D plates.

Development and Clinical Evaluation of MatrixMANDIBLE Subcondylar Plates System (Synthes)

In this article, authors report the different steps of development and clinical validation of MatrixMANDIBLE Subcondylar Plates (Synthes, Soletta, Switzerland), a specialized osteosynthesis system developed by Synthes during the past 4 years. Between 2009 and 2013, a total of 62 patients were treated for subcondylar and condylar neck fractures via a preauricular or retromandibular/transparotid approach. The MatrixMANDIBLE Subcondylar Plates System consists of a Trapezoidal Plate, a three-dimensional (3D) 4-hole 1.0-mm plate for smaller fracture areas, the Lambda Plate, a 7-hole 1.0-mm linear plate which mimics the two miniplates technique, and the Strut Plate, a 3D 1.0-mm plate with great versatility of employment. All devices satisfy the principles of a functionally stable osteosynthesis as stated by Champy et al. None of the plates broke and no macroscopic condylar displacement was noted on radiological follow-up. Clinical and functional parameters assessed at 6 months postoperative (mandibular range of motion, pain, dental occlusion) were almost restored. MatrixMANDIBLE Subcondylar Plates System (Synthes) has proved to provide sufficient mechanical stiffness and anatomically accurate fracture reduction to avoid major postoperative drawbacks of subcondylar and condylar neck fractures.

In Vitro Mechanical Evaluation of Mandibular Bone Transport Devices

Bone transport distraction osteogenesis (BTDO) is a surgical procedure that has been used over the last 30 years for the correction of segmental defects produced mainly by trauma and oncological resections. Application of BTDO has several clinical advantages over traditional surgical techniques. Over the past few years, several BTDO devices have been introduced to reconstruct mandibular bone defects. Based on the location and outline of the defect, each device requires a uniquely shaped reconstruction plate. To date, no biomechanical evaluations of mandibular BTDO devices have been reported in the literature. The present study evaluated the mechanical behavior of three different shaped prototypes of a novel mandibular bone transport reconstruction plate and its transport unit for the reconstruction of segmental bone defects of the mandible by using numerical models complemented with mechanical laboratory tests to characterize strength, fatigue, and stability. The strength test evaluated device failures under extreme loads and was complemented with optimization procedures to improve the biomechanical behavior of the devices. The responses of the prototypes were characterized to improve their design and identify weak and strong regions in order to avoid posterior device failure in clinical applications. Combinations of the numerical and mechanical laboratory results were used to compare and validate the models. In addition, the results remark the importance of reducing the number of animals used in experimental tests by increasing computational and in vitro trials.

Epidemiology and treatment outcome of surgically treated mandibular condyle fractures. A five years retrospective study

Surgical management of mandibular condyle fractures is still controversial. Although it provides better outcome than closed treatment questions still remain about the surgical approach and the osteosynthesis devices to be used. Between 2005 and 2010, we managed 168 mandibular condyle fractures with open treatment. Two surgical approaches were used in this study, a pre-auricular and a high submandibular approach (one or the other or as a combined approach). Internal fixation was performed using TCP(®) plates (Medartis, Basel, Switzerland) or with two lag screws (15 and 17 mm). Delta plates were used in 15 cases (8.9%). We report the epidemiology of these fractures and the outcomes of the surgical treatment. We assessed the complications related to the surgical procedure and those related to the osteosynthesis material. The facial nerve related complication rate was very low and the osteosynthesis materials used proved to be strong enough to realize a stable fixation. The two approaches used in this study appeared to be safe with good aesthetic results. Most of the surgical procedure failures occurred in high subcondylar fractures especially when bilateral.

Biomechanical analysis of titanium plate systems in mandibular condyle fractures: a systematized literature review

PURPOSE: To conduct a systematized review of the literature about the main methodologies used to evaluate the biomechanical fixation systems with titanium plates in fractures of the mandibular condyle. METHODS: A systematized review of literature was performed in the electronic databases PubMed, EMBASE, LILACS and MEDLINE without restriction of the publication date. The eligibility criteria were laboratory studies involving mandibular condyle fractures, studies using titanium plates, biomechanical studies, in vitro and computational studies involving the finite element method (FEM). RESULTS: Eleven articles that met the eligibility criteria were selected, including seven articles involving in vitro studies and four studies with biomechanical analysis by using FEM. CONCLUSION: Although few articles have used the finite element method, the results of in vitro studies were similar to those found in computational studies, regarding to the stable use of two titanium miniplates.

Comparative biomechanical evaluation of mono-cortical osteosynthesis systems for condylar fractures using photoelastic stress analysis

Fractures of the condyle account for 20-30% of all mandibular fractures, and are therefore one of the most common facial injuries. Precise evaluation of the mechanical stresses that develop in a fractured mandible is essential, particularly for the testing of systems currently used for stabilisation of the condylar fragment. Photoelastic stress analysis can be used to visualise alterations in the strain that is induced in the mandible by a fracture, and in the osteosynthesis materials used to stabilise it. This method, used on currently used osteosynthesis materials, showed that stabilisation of a subcondylar fracture with a single miniplate does not provide enough stability, whereas the use of two miniplates - properly positioned - offers sufficient stability in all loading conditions. A microplate may be used as a tension-resisting plate with equally good results.

A comparative clinical evaluation of the outcome of patients treated for bilateral fracture of the mandibular condyles

AIM

To compare open reduction and internal fixation (ORIF) with closed treatment and maxillomandibular fixation (CRMMF) for management of bilateral subcondylar fractures of the mandible.

PATIENTS AND METHODS

This study involved a retrospective analysis of bilateral subcondylar fractures of the mandible treated at Government Dental College, Rohtak from 2007 to 2010. Data were collected by a review of pertinent inpatient and outpatient clinic records, and radiographic results. Patients were followed up weekly for 4 weeks and then at 2, 3 and 6 months after surgery. At these visits, careful attention was paid to clinical parameters included mouth opening, protrusion, laterotrusion, deviation on mouth opening and occlusion.

RESULTS

The patient sample ranged in age from 19 to 55 years, with an average age of 28.2 years. In total, 44 patients with 88 mandibular subcondylar fractures were included in the study. Out of these, 20 patients were managed by closed treatment and 24 by ORIF of the subcondylar fractures (19 unilateral and 5 bilateral). Regarding mouth opening/lateral excursion/protrusion, significant (p=0.00) differences were observed between both groups (open 37.6/11.5/5.9 mm versus closed 31.5/7.8/3.1mm). The visual analogue scoring revealed significant (p=0.00) difference with less pain in the operative treatment group (1.3 open versus 7.2 closed). Statistically significant difference was found between two groups for occlusion (p=0.00).

CONCLUSION

The current retrospective study shows that operative treatment was superior in all objective and subjective functional parameters. It is concluded that if either of the condyles is displaced ORIF is the most satisfactory method of treatment.

Review of biomechanical experimental studies on different plating techniques of mandibular condyle fractures

Mandibular condyle fractures are one of the most frequent injuries of the facial skeleton. The option for open treatment of mandibular condyle fractures has become more favorable since osteosynthesis materials were developed in the past few decades. However, the rigid fixation techniques of treating condyle fractures remain one of the controversial issues in maxillofacial trauma. These injuries are currently treated by plate-screw osteosynthesis and, depending on the case, the bone segments are fixed by one or two miniplates. Several techniques and plate types like adaption miniplates, minidynamic compression plates, resorbable plates and double plates have been evaluated biomechanically in various experimental and clinical studies. The biomechanical and physical behavior of mandibles have been investigated by different approaches. It can be divided into computer biomodels (e.g., finite element analysis) and physical models. Physical models allow testing on a gross level to give fatigue performance and fracture strength. The aim of this article is to carry out a review of the literature which deals with biomechanical evaluation made with physical models of plating techniques of mandibular condyle fracture. Based on the results of these studies, osteosynthesis with two miniplates seems to be the most stable way of treating mandible subcondylar fractures, and PLLA plates were not strong enough compared with metal plates.

Prospective closed treatment of nondisplaced and nondislocated condylar neck and head fractures versus open reposition internal fixation of displaced and dislocated fractures

OBJECTIVE

assessment of open reduction internal fixation in displaced or dislocated fractures of the condylar neck and head assessed versus closed treatment of nondisplaced, nondislocated fractures.

MATERIALS AND METHODS

One hundred and twenty patients suffering from 158 fractures; classes II to V according to Spiessl and Schroll, e.g., displaced and dislocated fractures were operated on; classes I and VI nondisplaced, nondislocated fractures were treated conservatively. At 1year, facial symmetry, pain, facial nerve function, and scarring were assessed clinically; reossification and fragment angulation were assessed from radiographs; vertical position, incisal maximum movements, and condyle translation were judged by millimeters.

RESULTS AND DISCUSSION

Clinical courses were uncomplicated in classes I to IV and did reach horizontal and vertical fragment reposition with minor remodeling in follow-up. Single cases evinced persistent pain, dysocclusion, facial nerve palsy, and plate fractures. Results were less successful in classes V and VI: although open reposition internal fixation showed good repositioning in class V, marked vertical bone remodeling occurred; single cases suffered from pain, dysocclusion, and plate fracture. Class VI cases had the worst translation, likewise marked condyle remodeling, and frequent dysocclusion.

CONCLUSION

Classes V and VI remain challenging to treat, while the other classes can be treated reliably with this study's rationale. Condyle remodeling in classes V and VI, translation in class VI may benefit prospectively from even more careful mobilization, improved osteofixation as minimalized operation trauma.

Clinical experience with osteosynthesis of subcondylar fractures of the mandible using TCP plates

AIM

To evaluate the clinical and radiological results obtained with a new kind of osteosynthesis device (Modus TCP) plates, Medartis, Basel, Switzerland), especially designed for low subcondylar fracture (LSCF) and high subcondylar fracture (HSCF) of the mandible in association with the high submandibular approach (HSMA).

METHOD

A prospective clinical and radiological study was carried out over a 41-month period. All adult patients suffering from a displaced LSCF or HSCF who consented to the surgical treatment were included in the study. All fractures were operated on using an HSMA and were stabilised using a 4- or 9-hole TCP((R)) plate. No intermaxillary fixation was used and a soft diet was started on the 1st postoperative day. Clinical examinations and control X-rays were carried out on the 10th postoperative day, in the 1st, the 3rd and, at least, in the 6th postoperative months.

MATERIAL

Sixty-four patients (12 females, 52 males - mean age: 28.3) with a total of 75 fractures (54 LSCF, 21 HSCF) were included in the study. Mean postoperative follow-up was 14 months.

RESULTS

In the 6th postoperative month, all fractures were consolidated in 79% of the cases in an anatomical position. A secondary displacement of the fracture occurred in 6.6% of the cases. Plate fracture was not observed. Dental occlusion remained unchanged in 94% of the patients. The mandibular movements (mouth opening, protrusion, lateral movements on the unfractured and fractured side) had normal mean values (49.5, 10.4, 12.8, 12.1mm, respectively). These movements were symmetrical in 95% of the patients. No patient complained about articular pain or noise. No facial nerve palsy was noticed, not even a transiently one. All patients but one found the scars acceptable.

CONCLUSION

TCP plates, in association with HSMA, were found to be an efficient osteosynthesis device for stabilising subcondylar fractures.