Clinical significance the establishment of the C2-4 vertebra finite element model on anterior fixation for the treatment of Hangman fractures

CHENG Guo-fang; HE Bao-lin; WANG Xiao-wei; HUANG Zhi-yong

doi:10.3969/j.issn.1009-4237.2016.10.007

Abstract：Objective To biomechanically analyze the finite element model of Hangman fracture and to provide data for clinical work .Methods A healthy male volunteer was chosen and was performed spiral CT on his cervical vertebra from the 2nd to 4th section.The 3D data was imported into Mimics 14.0 software to form cervical vertebra from the 2nd to 4th section.Then the Hangman fracture model was obtained by the segmentation and other operations .Combined with three-dimensional anatomical data ,the pedicle screw and plate were made by Solidworks 2013 which could simulate three kinds of fixed model:pedicle screw fixation group ,C2-3 anterior plate fixation group and C2-4 anterior plate fixation group .The biomechanics of three kinds of fixation models and Hangman fracture model were compared.Results For the C2-3 segment,the angular displacements on each direction of the Hangman fracture model were more than other three fixation groups , especially for the flexion and extension;the angular dis-placements on each direction of the C 2-3 and C2-4 anterior plate fixation groups were similar and lower than other groups.For the C3-4 segment,the angular displacements on each direction of the C 2-4 anterior plate fixation group were lower than other groups;and the maximum difference of angular displacement was 0.15°between groups;the order of fixture force from high to low was C 2-3 anterior plate fixation group ,C2-4 anterior plate fixation group and pedicle screw fixation group ,respectively .The main force site of the two kinds of plate fixation was the root of screws and the maximum value was 54.73MPa;the main force site of pedicle screw was located through the fracture line and on the screw tip.Conclusion For Hangman fractures,the biomechanical properties of C 2-3 and C2-4 anterior plate fixation are more stable compared with traditional fixation method ,which is worth application .