Design And Biomechanical Study Of Anatomical Transoral Atlantoaxial Lateral Mass Fusion Cage And Zero-Profile Plate

Objective:To design an anatomical transoral atlantoaxial lateral mass fusion cage and zero-profile plate base on the CT scan data of 40 postoperative patients operated with TARP.And compare the stabilities of Z-P plate,the anatomical lateral mass fusion cage or iliac crest autograft combined with Transoral Atlantoaxial Reduction Plate(TARP)system and posterior C1-C2 pedicle screw-rod system.Method:Z-P plate and anatomical cage were designed based on the three-dimension parameters of 40 postoperative patients operated with TARP.Range of motion(ROM)in flexion-extension,left-right bending and axial rotation of 6 cadaveric specimens with different treatments were recorded by Motion Analysis,Co.6 Eagle.Results:1.The measured data indicated that feasible anatomical cage and Z-P plate design were in 3 sizes.ROM of unstable group increases obviously than that of intact group.2.The difference between the intact group and fixation groups was statistically significant.There is no statistically significant difference between group A and group C in all directions.ROM in left/right lateral bending of group A and group C is different to that of group B.Conclusion:1.The biomechanical study indicated that stiffness was analogous between Z-P plate,TARP system(combined with cage or iliac crest autograft)and posterior C1-C2 pedicle screw-rod system in extention/flection and axial rotation.However,Z-P plate and TARP system provide superior stiffness in left/right lateral bending.2.Furthermore,Z-P plate and cage combined with TARP may simplify surgery procedure and decrease the incidence of clinical application.