Research On Three-dimensional Finite Element Simulation And Biomechanical Analysis Of Maxillofacial Blast Injuries And Secondary Injuries In Skull Base

With the widely using of explosive objects in modern war and the daily production of human beings,the probability of blast injury is significantly increased.The region of the explosion is large,resulting in joint damage of multiple organs and multiple parts of the human body.The maxillofacial region is located in the exposed position of the human body,which is more likely to be damaged in the explosion.According to statistics,although the maxillofacial area is less than 12% part of the total body area,the incidence of blast injury in this area is higher than 40%.Analysis of the anatomical structure,the relationship between the maxillofacial region and the skull base is closely related.When the maxillofacial region is subjected to the impact of an explosion shock wave,the base tissue of the skull is often subjected to secondary damage.In the wars of Iraq and Afghanistan,the number of patients with brain damage related to the explosion may be more then 320,000.How to fully understand the injury mechanism,clinical manifestations and treatment principles of maxillofacial blast injury with craniocerebral injury has become an urgent problem for maxillofacial surgeons.The Finite Element Method(FEM)is a numerical calculation method based on computer operation in modern engineering analysis.It is one of the important methods in biomechanical research.This method is another form of representation of the structure,Geometric models with complex structures are subdivided into a series of subdivisions b y mathematical methods,simplify complex structures into a limited number of elements with simple geometry and the same properties,mathematically describe all elements,then calculate the mathematical equation to obtain the corresponding result.The successful application of the finite element method depends on the improvement of the alculate ability of the computer.In recent decades,with the rapid development of computer technology and the exploiting of various finite element software,the finite element method has been applied to modern engineering analysis for solving a variety of mechanical problems which had many complex structures.Our research group had established the finite element model of mandible blast injury of pigs and humans,dynamically simulated the process of blast injury process,and verified the high simulation of the finite model with animal experiments.Using finite element method to study maxillofacial blast injury can solve the ethical difficulties of animal experiment,have the better Operability and Repeatability.At present,there are few similar studies in the world.We established the three-dimensional finite element model of human maxillofacial blast injury by finite element method,and analyzed the biomechanical of secondary injuries of skull base caused by maxillofacial blast injuries,which provides theoretical foundation for the study on Secondary injury of the skull base caused by blast injury in different parts of the maxillofacial region.Methods:1.Recruit a qualified volunteer,and obtain digital medical images and communication format data of the the volunteer’s maxillofacial tissues by computed tomography.establish a three-dimensional finite element model of human skull with the using of softwear which include Mimics,Geomagic Studio,HyperMesh.2.Ls-dyna 971 R software was used to calculate the model and obtain the result file which were analyzed with HyperView,Ls-Prepost.Results:1.A three-dimensional finite element model of maxillofacial bone was successfully established.The geometric shape of the model is consistent with the skull of Volunteer,and has the mechanical characteristics consistent with the Volunteer’s skull.This model contains 510560 nodes and 857848 element.2.We successfully simulated the finite element model of maxillofacial explosion injury,conducted post-visualization processing of stress and strain,checked the accuracy of analysis results,and detected whether the various output indicators met the expected biomechanical requirements.3.Successfully simulated the blast injury on three parts of maxillofacial region,obtained the dynamic process of maxillofacial bone fracture,Stress distribution and conduction in the skull base.Conclusions:1.When the different parts of maxillofacial were impacted by blast wave,the stress concentration areas were related not only to the structure of skull base,but also to the stress conduction pathway.2.The finite element method can be used to simulate the process of maxillofacial blast injury,It provides an important methods to study the mechanism of skull base’s secondary injury caused by maxillofacial blast injury.3.The three-dimensional finite element model of maxillofacial explosion injury established in this study only considers about the injury effect of blast wave.Other injury factors were not taken into account,so there was still a big gap in the simulation of blast injury,which needs to be more improved in future.