الملخص
BACKGROUND:In recent years,the treatment method of injecting bone cement into the intervertebral space has been introduced from abroad for the treatment of lumbar recurrent pain caused by lumbar disc degeneration and intervertebral space narrowing;however,some patients had vertebral fractures after treatment;the fracture may occur because the bone cement injected into the intervertebral space has a poor elastic modulus. OBJECTIVE:To analyze the effect of bone cement with different elastic moduli injected into the intervertebral space on the maximum stress of upper and lower vertebrae using a three-dimensional finite element model. METHODS:A volunteer with normal spine was recruited to obtain CT data.The finite element model of L2-L5 lumbar spine was established using Mimics,Geomagic,SolidWorks,and Ansys.Subsequently,a L3-L4 intervertebral space injection model with different doses(1 mL and 4 mL)of bone cement was established.Four different elastic moduli(1 000,2 000,4 000,and 8 000 MPa)were assigned to bone cement at each dose.Pressure and bending moment were applied on the surface of the L2 vertebral body to analyze the stress on the lower surface of the L3 vertebral body and the upper surface of the L4 vertebral body. RESULTS AND CONCLUSION:(1)In the case of the same amount of bone cement injection,as the elastic modulus of bone cement increased,the stress on the lower surface of L3 vertebral body and the upper surface of L4 vertebral body increased.Among them,the bone cement with an elastic modulus of 1 000 MPa had the least effect on the lower surface of L3 vertebral body and the upper surface of L4 vertebral body.Bone cement with elastic modulus of 8 000 MPa had the greatest effect on the lower surface of L3 vertebral body and the upper surface of L4 vertebral body.Bone cement with different elastic moduli had little effect on the motion range of the whole lumbar spine.(2)The results indicate that injecting bone cement with lower elastic modulus while meeting treatment requirements can reduce the risk of postoperative fractures.