Development And Finite Element Analysis Of The Anatomic 3D Printing Porous Titanium Cage For Lumbar OLIF Approach

Objective:To develop an anatomic 3D printing porous titanium intervertebral fusion cage for specific application in the oblique lumbar interbody fusion(OLIF).To study the biomechanical attributes of the anatomic 3D printing porous titanium cage in OLIF surgery by three dimensional finite element analysis.Methods:1.New anatomic 3D printing porous titanium cage were designed according to the anatomical characteristics of the chinese lumbar,mean curve of the lumbar endplates and 3D printing porous titanium material properties.2.A 3D finite element model of regular human L3-5 was established,and the validity of the model was verified.3.Based on the intactmodel,the new anatomic 3D printing porous titanium cage,the normal cage and the individuation cage were fitted to the L3-4 vertebral body in order to simulate the OLIF operation process and validate the applicability of new anatomic cage in lumbar segments.4.Analysed the maximum stress,stress distribution of the three kinds of cage and the ROM of the L3-L4.Results:1.A new lumbar anatomic 3D printing porous titanium cage for specific application in the OLIF was designed and developed successfully.the "curved surface" design of new cage can better meet endplates structure.2.The normal finite element model of L3-L5 mobility under various load conditions was reported in the literatu.3.Based on the intactmodel,Its validated that the applicability of new anatomic cage in L3-4 lumbar segments.4.The maximum stress of the anatomic cage was 75.367、24.625、47.082、56.879、40.569、51.290 MPa,the normal cage was 101.129、43.129、62.071、70.226、58.649、68.70 MPa,the individuation was:91.465、49.169、60.272、50.388、68.763、56.376 Mpa,In thel finite element analysis of simulated OLIF operation in L3-L4 segment,under the motion of flexion,extension,bending and rotation.By the same way,we find that the L3-L4 vertebral displacement distance of the new anatomic 3D printing porous titanium cage group are 0.62、0.55、0.1、0.06、0.11、0.12,the universal cage group are 0.62、0.55、0.1、0.06、0.11、0.12,and the individuation cage group are 0.61、0.55、0.11、0.05、0.11、0.09,but the regular human L3-L4 vertebral displacement distance are 2.7、3.8、3.3、3.45、3.2、3.41.5.The L3-L4 vertebral activities of three groups is the same,but the maximum stress of the anatomic cage and individuation cage is less than the normal cage group.Conclusions:1.The anatomic 3D printing porous titanium intervertebral fusion cage can satisfy the need of XLIF/OLIF surgically.2.The regular human L3-L5 finite element model is verified to be valid and can be used in the following 3D finite element analy.3.The application of new anatomic cage in the OLIF surgery can decrease the maximum stress,avoid stress concentration and reduce vertebral activity,as good as the individuation one.