Finite Element Method Model Of The Atlas Posterior Arch Fractures And Internal Fixation Of The Finite Element Analysis

Objective:In this paper, finite element method fracture of the posterior arch of atlas three-dimensional finite element model and simulate the internal fixation biomechanical model analysis and verification, in order to further diagnosis and treatment of clinical fractures of the posterior arch of atlas provide a theoretical basis.Methods:(1) The coordinate data of healthy men's atlas was got by SCT. Then the picture data was converted to ASCII cloudy point by MIMICS. The point data was deal with CATIA software. GEOMAGIC STUDIO and CATIA were used to establish geometry model. The pre-post was carried out by HYPERMESH and LS-DYNA. The finite model was loaded and validated by some test data. (2) The underside of C2 in the healthy atlantoaxial model was fixed, and the significant movement of neck was simulated such as pitching, axial large load, to understand atlantoaxial model under the condition of various movements and forces. (3) Fracture model is treated with internal fixation operation to simulate the normal cervical spine motion, and thus test the feasibility of surgery.Results:1) The established finite element model of upper cervical spine, which contains a total of 35719 nodes,8797 elements, has accurate appearance and good geometric similarity; 2) Using upper cervical spine model (C0-C2) and exerting surface pressure on occipital simulates the situation that when head is in neutral, anteflexion, extension positions, atlas anterior arch is acted by the largest force, followed by the posterior arch and lateral mass; 3) Using atlas model alone and exerting force to upper joint surface of atlas simulates the situation that when head is in neutral, anteflexion, extension positions, atlas maximum stress concentrates on anterior arch and secondary stress concertrates on lateral mass and the junction between posterior arch and lateral mass; directly exerting force to posterior arch simulates the situation that when head is in the position of over-extension, the maximum stress concentrates on the junction between posterior arch and interal mass.4) Finite element analysis of internal fixation model after simulated surgery to the model of atlas posterior arch fracture concludes that when simulating the situation that head is in neutral, anteflexion, extension positions, there is stress concentration in position of screw, but in the ideal range.Conclusion:1, the model looks realistic with the experimental requirements, the data and images can be reused.2, the model can be applied accurately simulated and idealized boundary load conditions, which verifies the fracture mechanism of injury.3, model validation after internal fixation of posterior arch of atlas fracture fixation plate and screws there is stress concentration, but still within the ideal range, show that the surgical method is reliable.