颈椎后凸畸形山羊动物模型:力学失衡及异常应力

Mechanical imbalances and abnormal stress in a goat model of cervical kyphosis

背景：颈椎后凸畸形发生的同时其生物力学行为也发生变化,但关于颈椎后凸畸形动物模型的生物力学研究少见文献报道。目的：分析颈椎后凸畸形山羊动物模型的生物力学变化。方法：通过外加因素,模拟颈椎后凸畸形的形成病因,构建颈椎后凸畸形山羊的动物模型,并对颈椎后凸畸形山羊和正常山羊的新鲜颈椎标本作生物力学的对比研究,测量其三维运动范围和弯曲刚度。结果与结论：与正常山羊颈椎标本比较,颈椎后凸畸形山羊后凸范围在C2-5,颈椎后凸畸形山羊在C2/3-C4/5节段的三维运动范围明显减小,而在C5/6节段此差距明显缩小,在C6/7节段基本无差别,甚至会略大于正常山羊颈椎三维运动范围,在屈伸、左右侧屈、左右旋转运动中,旋转运动下降最多,旋转活动基本被限制;颈椎后凸畸形山羊在C2/3-C4/5节段的弯曲刚度明显增大,而在C5/6和C6/7节段两者较接近。反映了在施加实验因素后,羊的颈椎出现了生物力学的改变,羊颈椎在出现后凸畸形后变得僵硬了。结果提示后颈椎后凸畸形形成后,后凸节段颈椎的力学失衡和异常应力的存在造成颈椎关节的异常融合,导致了颈椎生物力学特征的改变。

BACKGROUND：The incidence of cervical kyphosis occurs with bio-mechanical behavior changes.However,bio-mechanics research of animal model of cervical kyphosis has been rarely reported. OBJECTIVE：To analyze biomechanical changes in a goat model of cervical kyphosis. METHODS：To simulate the formation of cervical kyphosis cause,a goat model of cervical kyphosis was made.Biomechanics of fresh cervical specimens of the cervical kyphosis goats and normal goats was compared to measure three-dimensional range of motion（ROM）and bending stiffness. REULTS AND CONCLUSION：Compared with normal specimens,the deformity range of cervical kyphosis goats was from C2 to C5,and their ROM in the C2/3 to C4/5 segment was obviously reduced.ROM differences between two groups in C5/6 segment was significantly reduced,similar in the C6/7 segment,even slight greater than normal specimens.The rotation motion was significantly reduced,nearly limited.The bending stiffness of the kyphosis group was increased significantly in the C2/3 to C4/5 segment,while almost the same as normal group in the C5/6 and C6/7 segments.With the formation of kyphosis,mechanical imbalances and the presence of abnormal stress in the deformity range resulted in abnormal cervical joint fusion,leading to cervical biomechanical changes.