Finite Element Modeling And Analysis Of Anterior Cervical Fixation System In Children

OBJECTIVE: To establish a three-dimensional finite element model of children's cervical vertebra,and to provide experimental basis for the study of biomechanical characteristics and injury mechanism of children's neck.METHODS: The finite element model of the lower cervical vertebra of a 6-year-old child was established in a complete and detailed manner.On the basis of verifying the validity of the model,a further comparative analysis was conducted on the personalized series of children's anterior cervical locking internal fixation system designed by ourselves(Anterior cervical Orion plate fixation,ACOP,Anterior cervical vertebral locking plate fixation,ACVLP,Anterior cervical single cortical pedicle locking plate fixation,ACSLP,Anterior cervical bicortical pedicle locking plate fixation,ACBLP),and obtained the patent authorization of "a locking internal fixation system for anterior cervical screw"(ZL201822056700.9).The finite element mechanical properties of the four different anterior cervical internal fixation systems,the finite element comparative analysis of the screw-bone tensile strength test,the displacement and stress peak of the internal fixation methods.RESULTS AND CONCLUSIONS: 1.The 3D finite element model of children's cervical vertebra,the complex anatomical structure and the changing characteristics of the geometric size of each vertebra were successfully simulated and constructed,providing a new computational method for the subsequent damage mechanism research.2.The validity of the 3D finite element model is verified with 6 working conditions(forward bending,backward stretching,left and right lateral bending,and left and right rotation).3.In each model,the stress of ACBLP vertebral body and its accessories was the least,the internal fixation was the best,and the effect on adjacent segments was relatively small,followed by ACSLP.4.In anterior cervical bicortical pedicle screw internal fixation(ACBS),screw holding ability or anti-pull ability is better,while that of monocortical internal fixation is the second,indicating that pedicle internal fixation has more stability than only centruminternal fixation.5.In the process of screw pulling out,the front of the screw rod bears the maximum stress,and the stress is attenuated in the process of transferring to the middle and tip.6.The maximum stress peak was found in the cervical centrum of all the internal fixation models.7.Anterior cervical Orion screw and vertebral body locking screw internal fixation have no screw in the pedicle,so the pedicle was almost powerless to biomechanics transmission.8.In anterior cervical single and biocortex pedicle screw fixation,the peak stress of the latter pedicle was significantly higher than that of the monocortex.