Finite Element Analysis Of Improved Spinal Correction System

Objective: To establish a three-dimensional finite element model of L1-L3 spinal column of normal adult male,to simulate posterior pedicle screw fixation and modified spinal correction system fixation,and to analyze the biomechanical characteristics of the three models.Methods: CT images of L1-L3 in an adult male were collected,and a complete 3D finite element model of L1-L3 was established by means of Mimics 16.0,geographic studio 11.0 and ansys14.0 software.Furthermore,the models of rigid pedicle screw one rod system internal fixation,dynamic pedicle screw rod system and improved spine correction system were constructed and the operation of posterior 3D orthopedic operation was simulated by von Mises stress peak analysis three sets of system stress distribution.Three dimensional finite element model of normal spine L1-L3,pedicle screw model and improved fixation model of spine correction system were successfully established,Three dimensional finite element analysis method was used to simulate physiological load(apply 500 N axial stress to the L1 vertebral body)and appropriate moment(apply 10 N.M lateral torque to the L1 vertebral body on the basis of axial stress)in the case of forward bending,backward bending,left and right side bending,left and right rotation,etc.the three correction systems and the normal spinal model were compared and analyzed to simulate the stress distribution characteristics and stress after operation Shunting,strain,stability and strain angle.Results: Under the stress of 500 N in the axial direction,10 N.m of torque is applied to perform flexion,dorsiflexion,lateral bending and horizontal rotation.During flexion and dorsiflexion,the maximum stress of the vertebral discs of L1/2 and L2/3 intervertebral discs After system B,they are all smaller than the modified spinal correction system C,and the maximum stress of the vertebral body B system is the largest in the L1 vertebral body and the maximum stress in the middle vertebral body L2 is the smallest.The maximum stress figures of the intervertebral discs of the B system and the C system are close when the scoliosis and rotation.By calculating the stress shielding rate,the stress shielding rate of the L1/2 and L2/3 intervertebral discs of the C system and the stress shielding rate of the L2 vertebral body of the intermediate vertebral body were significantly lower than those of the B system.The angular displacement of flexion and extension and the maximum displacement of L1-L3 are B<C<A from small to large.The angular displacements B and C are very close during side bending and rotation,and the maximum displacements B and C during side bending C is also close,but the maximum displacement of horizontal rotation C is significantly smaller than B.The bending stiffness in different directions is B>C>A.Conclusion: the improved spinal correction system can effectively achieve the effect of spinal fixation,and can better stress shunt and reduce the effect of stress shielding,which provides a theoretical basis for the promotion and application of the improved spinal correction system.