Study On The Optimization Of Intervertebral Fusion In Patients With Osteoporosis

Osteoporosis is a common bone disease in the society at present.With the deepening of social aging,lumbar diseases related to osteoporosis are becoming more and more common.Conservative treatment often can not alleviate the pain,and the treatment effect can only be achieved by using interbody fusion to reduce the internal pressure of the pathological lumbar segment.At present,the posterior fixation system provides the posterior support for the intervertebral fusion and is an important part of the intervertebral fusion.Osteoporosis reduces the holding power of the bone for the posterior fixation system,and the failure rate of conventional intervertebral fusion is high.The bone cement nail strengthening technique will bond the screw and the vertebral body through bone cement,improve the anti-pullout ability of the screw,and reduce the risk of fusion failure.However,the use of bone cement causes complications of bone cement leakage.The more use of bone cement,the higher the risk of serious consequences caused by complications.The main purpose of this paper is to reduce the use of bone cement and maintain sufficient posterior fixation effect.In this paper,the biomechanical data of lumbar interbody fusion are obtained by finite element analysis.The main steps are as follows.First,the CT image is imported into Mimics software,and the three-dimensional geometric model of lumbar spine bone is reconstructed.Then,use 3-matic software to optimize the surface of the three-dimensional geometric model of the lumbar spine,add lumbar structures such as intervertebral disc and endplate cartilage,and establish the L3-5 lumbar spine model that conforms to the human physiological structure.Use the mesh division function of 3-matic software to divide the face mesh and volume mesh of the lumbar model.Finally,the material attributes,load application and contact setting of the lumbar model are completed in the ANSYS software.The models established in this paper include the normal lumbar spine model of L3-5 and L4-5 segments,the L4-5 unilateral posterior fixation model and the L4-5 bilateral posterior fixation model.By adjusting the material properties of the model in Ansys software,the lumbar characteristics of osteoporosis patients and normal bone mass are realized,and the applied load is changed to simulate the forward bending,backward extension,lateral bending and rotation of the human lumbar spine.Observe and analyze the equivalent stress of the nail rod system,the nail path and the bone cement,and obtain the experimental results.The results showed that in a bilateral posterior fixation model,the reduction of two screws with bone cement reinforcement can still achieve a posterior fixation effect of all screws with bone cement reinforcement.Through the comparative analysis of multiple groups of experimental data,it is found that proper change of the screw fixation mode in the posterior fixation system can improve the posterior fixation effect of the low bone mass lumbar model.The use of bone cement nail reinforcement can improve the posterior fixation effect of patients with osteoporosis.Proper reduction of the number of bone cement nail reinforcement can still achieve good fixation effect and reduce the risk of complications.