Comparison of two internal fixation systems in lumbar spondylolysis by finite element methods

•Finite element method was used to compare the internal fixation methods of lumbar spondylolysis.•Two types of lumbar spondylolysis internal fixation systems: pedicle screw-U shape rod (PSUSR) and pedicle screw-vertebral plate hook (PSVPH) internal fixation systems.•Based on CT images, four models are established by threshold segmentation and contour line reconstruction algorithm.•After finite element analysis, the PSVPH internal fixation system has better biomechanical properties.