压缩载荷下猪腰椎间盘髓核摘除后力学行为的实验研究

为研究退变及摘除髓核后腰椎间盘的力学行为,对猪腰椎间盘进行压缩实验。髓核摘除并经胰蛋白酶处理后的椎间盘作为实验组,正常椎间盘作为对照组。考虑载荷大小及加载速率的影响,得到椎间盘应力和应变关系、瞬时弹性模量及蠕变性能,并建立了蠕变本构模型。结果发现:随着压缩载荷和加载速率的增大,实验组的应变及蠕变与对照组相比均明显增大,瞬时弹性模量与对照组相比则明显减小,这表明髓核摘除后,椎间盘的承载能力受压缩载荷大小及加载速率的影响明显大于正常椎间盘。实验组仍可以采用Kelvin三参量固体模型描述其蠕变性能,预测腰椎间盘去核后的蠕变行为。研究结果可为椎间盘疾病的临床治疗及术后康复提供理论基础。

Experiments study on mechanical behavior of porcine lumbar intervertebral disc after nucleotomy under compression

In order to study the mechanical behavior of degeneration and nucleotomy of lumbar intervertebral disc, compression experiments with porcine lumbar intervertebral discs were carried out. The lumbar intervertebral discs with trypsin-treated and nucleus nucleotomy served as the experimental group and the normal discs as the control group.Considering the effects of load magnitude and loading rate, the relationship between stress and strain, instantaneous elastic modulus and creep property of intervertebral disc were obtained. The creep constitutive model was established. The results show that the strain and creep strain of the experimental group increase significantly with the increase of compression load and loading rate, whereas the instantaneous elastic modulus decreases obviously, compared with the control group. It indicates that the effect of load magnitude and loading rate on load-bearing capacity of intervertebral disc after nucleotomy is larger obviously than that of normal disc. The creep behavior of the experimental group can be still predicted by the Kelvin three-parameter solid model. The results will provide theoretical foundation for clinical treatment and postoperative rehabilitation of intervertebral disc disease.