Abstract Objective To analyze biomechanical stability of cortical bone trajectory system inthe osteoporotic type-A3 thoracolumbar fractures.Methods Six fresh thoracolumbar spinal function units (L1~3) were harvested from old cadaver spines.Bone mineral density (BMD) was measured for all the vertebral bodies.The ranges of motion of all specimens were detected on the MTS-858 spinal biomechanics testing instrument under different states respectively,normal state,classic pedicle screw fixation,cortical bone trajectoryscrew fixation,type A3 L2 vertebral body fracture classicpedicle screw fixation,and type A3 L2 vertebral body fracture cortical bone trajectory screw fixation.Results Ranges of motion at flexion,extension,left bending,right bending,left axial rotation and right axial rotation were significantly lower in the cortical bone trajectory screw group and classic pedicle screw group than in the normal state group (P<0.01).There were no significant differences between the rages of motion of the cortical bone trajectory screw fixation group and classic pedicle screw fixation group.The ranges of threedimensional motion were significantly lower in the type A3 L2 vertebral body fracture classic pedicle screw fixation group and type A3 L2 vertebral body fracture cortical bone trajectory screw fixation group than in the normal state group (P<0.05).Likewise,there were no significant differences between the range of motion of the type A3 L2 vertebral body fracture classic pedicle screw fixation group and type A3 L2 vertebral body fracture cortical bone trajectory screw fixation group (P>0.05).The range of motion between the classic pedicle screw fixation group and the type A3 L2 vertebral body fracture classic pedicle screw fixation group was insignificant (P>0.05).Conclusion These results confirmed that cortical bone trajectory technology can obtain similarimmediatestability as the traditional pedicle screw fixationinthe osteoporotic type-A3 thoracolumbar fractures.Simultaneously,it is a good choice for the osteoporotic type-A3 thoracolumbar fractures.
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