Comparison of biomechanics among three different internal fixation operations in thoracolumbar fractures

ZHU Tong; MA Lin; HUA Shuang-lin; QIN Hong

doi:10.3969/j.issn.1009-4237.2017.05.004

Abstract：Objective To compare the biomechanics data among three different internal fixation operations in thoracolumbar fractures. Methods Thirty-two cases of fresh pig spinal specimens(T13-L5) were selected and randomly divided into normal group(4 cases),transvertebral short segment group(4 cases),three segments group(4 cases) and long segment group(4 cases).They were made into thoracolumbar fractures models and corresponding internal fixation except the normal group.The axial compression stiffness and range of motion(ROM) of flexion,extension,lateral flexion and rotation were compared among the four groups. Results There was no significant difference in the ROM of flexion[(1.19±0.27)°vs.(1.29±0.48)°],extension[(1.13±0.34)°vs.(1.02±0.46)°],lateral flexion[(2.01±0.66)°vs.(1.94±0.61)°] and rotation[(2.48±0.50)°vs.(2.59±0.48)°] between the three segments group and the long segment group(P>0.05);the ROM of flexion[(1.19±0.27)°vs.(2.50±0.41)°],extension[(1.13±0.34)°vs.(1.70±0.44)°],lateral flexion[(2.01±0.66)°vs.(3.44±0.85)°] and rotation[(2.48±0.50)°vs.(3.24±0.65)°] in the three segments group were lower than those of the transvertebral short segment group(P<0.05).There was no significant difference in axial compression stiffness between the three segments group and the long segment group[(194.12±99.83) N/mm vs.(238.36±96.01) N/mm,P>0.05];the axial compression stiffness of the three segments group was higher than that of the transvertebral short segment group[(194.12±99.83) N/mm vs (157.91±52.87) N/mm,P<0.05]. Conclusion Both three segments fixation and long segment fixation show excellent spinal stability in burst thoracolumbar fractures.However, three segments fixation fixes less vertebrae with more flexibility.