斜扳手法对人体腰椎间盘退变后三关节复合体的力学效应

Mechanical effect of oblique-pulling manipulation on triarticular complex after human lumbar intervertebral disc degeneration

背景:斜扳法治疗腰椎间盘退变的生物力学研究主要集中于纤维环、髓核及骨性结构的应力及位移分析,对腰椎间盘退变后三关节复合体的力学研究目前较少见。目的:通过有限元分析斜扳手法对腰椎间盘退变后三关节复合体生物力学的影响。方法:将人体腰部CT图像导入到Mimics、Geomagic studio、solidworks、Hypermesh等有限元软件,构建L、L椎体、椎间盘、韧带、关节囊等有限元模型。根据腰椎间盘退变材料属性的不同分别给予赋值,建立正常及轻度、中度退变腰椎模型,分析斜扳法对不同退变程度腰椎间盘三关节复合体的力学分布影响。结果与结论:(1)斜扳手法作用后,正常及轻度、中度退变椎间盘的最大应力分别为0.78,3.21,3.94 MPa,而对应的椎间盘最大位移逐渐减少;(2)斜扳手法作用后,正常及轻度、中度退变椎间盘的纤维环应力逐渐增大,中度退变椎间盘的纤维环应力明显增加;正常及轻度、中度退变椎间盘髓核内的最大应力分别为0.87,0.56,0.44 MPa,关节囊的最大拉伸高度分别为1.74,2.48,3.10 mm;(3)结果表明,正常椎间盘能减少腰椎三关节复合体的应力加载,起到保护作用;斜扳手法对中度退变椎间盘的操作是安全的,其最大应力值不会造成腰椎组织的破坏。

BACKGROUND:Biomechanical studies on the treatment of lumbar intervertebral disc degeneration by oblique-pulling manipulation mainly focus on the stress and displacement analysis of the annulus fibrosus,nucleus pulposus and bony structure,while mechanical studies on the three-articular complex after lumbar intervertebral disc degeneration have not been found.OBJECTIVE:To analyze the biomechanical dynamic changes of the three-joint complex after lumbar intervertebral disc degeneration by oblique-pulling manipulation with finite element method.METHODS:CT images were imported to Mimics,Geomagic Studio,Solid Works,Hypermesh and other finite element software to construct Land Lvertebral body,intervertebral disc,ligament,joint capsule and other finite element models.According to the different material properties of lumbar disc degeneration,the values were assigned to establish normal,mild and moderate degeneration models.The mechanical distribution differences of the three-joint complex with different degrees of lumbar disc degeneration were analyzed by oblique-pulling manipulation.RESULTS AND CONCLUSION:(1) After oblique-pulling manipulation,the maximum stresses of normal,mild and moderate degenerative intervertebral discs were 0.78,3.21,and 3.94 MPa,respectively,while the corresponding maximum displacement of the intervertebral disc gradually decreased.(2) After obliquepulling manipulation,the annulus fibrosus stress of normal,mild and moderate degenerative intervertebral discs increased gradually,and the annulus fibrosus stress of moderate degenerative intervertebral discs increased significantly.The maximum stresses in the nucleus pulposus of normal,mild and moderatedegenerative intervertebral discs were 0.87,0.56,and 0.44 MPa,and the maximum stretched heights of the joint capsule were 1.74,2.48,and 3.10 mm,respectively.(3) The results suggest that the normal intervertebral disc without degeneration can reduce the stress loading of the lumbar triarticular complex and play a protective role.Oblique-pulling manipulation of moderate degenerative intervertebral disc is safe,and its maximum stress will not cause damage to lumbar tissue.