Intervertebral Disc Modeling And Surgical Evaluation Based On Finite Element Method

In recent years,intervertebral disc disease has become one of the most common lumbar diseases.Due to the complexity of the lumbar structure,current surgical treatment is discectomy.Although some patients' conditions are alleviated in the clinical symptoms,there are still some cases of symptoms continue and become even more severe.Therefore,in this paper,we will model and analyze the lumbar L4-L5 section with the normal intervertebral disc,on the basis of that,the lumbar L4-L5 section with the disc herniation will be modeled to compare with the normal one.By simulating the operation of the intervertebral disc,the postoperative models are obtained to be used for study,which can provide theoretical foundation and guidance for clinical medicine.The main works are as follows:1.The finite element method is used to simulate the biological morphology structures of lumbar spine,calculate and analyze the displacement and stress in different states,which providing further scientific basis for medical diagnosis and surgical treatment.This study aims at rebuilding the mechanical model of lumbar intervertebral disc with finite element method,simulating the situations of intervertebral disc herniation,intervertebral disc removal and intervertebral fusion,which gains the corresponding postoperative model.Firstly,three-dimensional reconstruction of the model is rebuilt by using CT data and MRI data.Secondly,the reconstruction methods of surface rendering and volume rendering are introduced,and its advantages and disadvantages are analyzed as well.Furthermore,based on the medical software modeling method,the reconstruction of lumbar L4-L5,including intervertebral discs and partial ligaments,are achieved by medical modeling software Mimics and Simpleware.2.The finite element model is generated by smoothing,meshing,setting material properties and defining the connection relation on the reconstruction model,applying different loads and freedom degree constraints to the model in software ANSYS to simulate the different states of human being's movements,and gaining the corresponding deformation,displacement and stress nephograms to verify the validity of the model.Comparing with the intervertebral disc herniation model and analyzing the changes of the displacement and stress.3.We establish the L4-L5 model of completely removed and intervertebral fused by simulating intervertebral disc surgery.The two models are subjected to the same concentrated force and freedom degree constraints as the normal model,which can proceed postoperative evaluation.We analyze the displacement and stress changes of the normal lumbar model,the nucleus completely removed model and the intervertebral fusion model under different movement states,providing some certain scientific reference for the treatment and postoperative recovery of clinical lumbar disc disease.