Stress-strain relations of single-level vertebrae compression fracture in rabbits

doi:10.3969/j.issn.2095-4344.1035

Abstract

Abstract:

BACKGROUND: Spine is the central axis of the body, and has complex structure and versatile functions. Spinal injury will not only affect the sensory and movement systems, but may even result in life-long disability or life-threatening injuries.

OBJECTIVE: To analyze the stress-strain relations of the rabbit vertebrae obtained by uniaxial compression, and to explore the effects of rabbit age, body weight, and vertebral body type on the vertebral load, stress, and strain in order to provide biomechanical guidance to spinal compression fractures.

METHODS: Axial and lateral compression experiments of the vertebral body were performed through a material properties tester, strain gauges were attached to the ventral middle part of the vertebral bodies, and the data such as the load of the tester and the strain were recorded. The sectional area of vertebrae was obtained by CT scanning for rabbit spine.

RESULTS AND CONCLUSION: (1) The rabbit age had a significant effect on the ultimate load, and with age increasing, the ultimate load of most of vertebrae could bear was increased. (2) The vertebral body at the turning point of spine physiological bending was liable to fracture or damage. (3) Our results can be employed to validate the finite element analysis model of rabbit vertebral compression.

中国组织工程研究杂志出版内容重点：人工关节；骨植入物；脊柱；骨折；内固定；数字化骨科；组织工程

Key words: Spinal Injuries, Fractures, Compression, Biomechanics, Tissue Engineering

CLC Number:

R459.9

Li Zhou, Han Shibing, Zhang Yuwen, Guo Yuan, Zhang Xushu . Stress-strain relations of single-level vertebrae compression fracture in rabbits[J]. Chinese Journal of Tissue Engineering Research, 2019, 23(4): 538-544.

Figures/Tables 5

通过对材料性能试验机和应变仪测量的数据进行处理和分析，得到椎体的载荷-位移曲线、载荷-时间曲线、应变-时间曲线，再通过软件测量出应变计粘贴位置的椎体横截面积，进而计算出椎体整体压缩(名义应力、名义应变)和应变计所在局部位置的应力-应变曲线(名义应力、应变计的点应变)，最后获得椎体破坏的极限载荷、极限应力等数据。 2.1 椎体的载荷-位移、应变-时间曲线实验通过Instron 5544万能材料试验机获得了各椎体的载荷、位移数据，以位移为横坐标、载荷为纵坐标作图，可得各椎体的载荷-位移曲线，见图3-5。图3A，图4A，图5A所示分别为2#兔C3、A#兔T2、28#兔L7的载荷-位移曲线。将XH5699动静态应变测试分析系统获得应变计的应变数据，以时间为横坐标、以应变为纵坐标，可得各椎体应变计位置的应变-时间曲线，图3B，图4B，图5B所示分别为2#兔C3、A#兔T2、28#兔L7的应变-时间曲线，其中一条应变曲线为颈椎椎孔内腹侧一个应变计数据，2条应变曲线为椎体腹侧中央左、右2个应变计的测量数据。图3A、图4A，图5A所示的椎体载荷-位移曲线均呈现出2个明显的波峰，图3B，图4B，图5B所示的椎体应变-时间曲线均呈现出2个明显的波谷，均表明脊椎在压缩过程中都发生了2次较大破坏，且椎体破坏位置与兔龄无关。椎体压缩实验结果见图6，颈椎见图6A，在椎弓位置处有2个明显的裂痕，中间1位置较大裂痕是第1次破坏形成，并与载荷-位移曲线的第1个波峰、应变-时间曲线的第1个波谷相对应；两侧2位置较小裂痕是第2次破坏形成，与载荷-位移曲线的第2个波峰、应变-时间曲线的第2个波谷相对应，且第2次破坏的载荷明显大于第1次；胸椎压缩实验结果见图6B，椎弓处的裂纹是第1次破坏，椎体破坏是第2次，且第1次破坏的载荷要大于第2次；在腰椎的压缩实验中，第1次破坏发生关节突骨折，见图6C所示，第2次破坏是椎体骨折，见图6D所示，而且2次破坏的载荷数值上相差不大。"

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