Biomechanical study of transpedicular fixation via injured vertebra plus connector for short-segment instrumentation of the spinal fracture

English Keywords:Spinal fracture  Pedicular screw  Fixation of the fractured vertebra  Stability

English Abstract:

  【Abstract】 Objective：To investigate the biomechanical stability of transpedicular fixation via injured vertebra plus connector for short-segment instrumentation of the spinal fracture.Method：L3 vertebral body fracture model were made on 5 fresh calf lumbar spine specimens，the stability of the L2-L4 segment with regard to intact specimens（control group），fractured model specimens（fracture group），transpedicular fixation via injured vertebra（6-screws construct） and transpedicular fixation via injured vertebra plus connector（6-screws plus connector construct） were tested for the range of motion（ROM） in flexion-extension，lateral bending and axial rotation.Result：The ROM of L2-L4 in flexion-extension，lateral bending and axial rotation of the fracture group was more than the intact specimens，which showed significant difference（P<0.05）.The ROM in flexion-extension，lateral bending and axial rotation of 6-screw and 6-screws plus connector constructs was smaller than those of the fracture group（P<0.05）.Two instrumentation group exhibited a smaller ROM in flexion-extension and lateral bending compared with the intact specimens（P<0.05）.There was no siginificant difference in the flexion-extension and lateral bending ROM between two instrumentation groups（P>0.05），but 6-screw plus connector constructs had smaller axial rotation ROM than that 6-screws constructs alone（P<0.05）.Conclusion：Transpedicular fixation via injured vertebra can enhance the biomechanical stability of the short-segment pedicle fixation system.Additionally，transpedicular fixation via injured vertebra plus connector is superior than the single 6-screw construct in providing axial rotation stability.