Department of Mechanical Engineering, Polytechnique Montreal, Quebec, Canada.
Julius Wolff Institut, Charité - Universitätsmedizin Berlin, Augustenburger Platz 1, 13353 Berlin, Germany.
J Biomech. 2020 Mar 26;102:109441. doi: 10.1016/j.jbiomech.2019.109441. Epub 2019 Oct 22.
Human lumbar motion segment is composed of various components with distinct contributions to its gross mechanical response. By employing experimental and computational approaches, many studies have investigated the relative role of each component as well as effects of various factors such as boundary-initial conditions, load magnitude-combination-direction, load temporal regime, preload, posture, degeneration, failures and surgical interventions on load-sharing. This paper reviews and critically discusses the relevant findings of in vitro and finite element model studies on load-sharing in healthy, aged, degenerate and damaged human lumbar motion segments. Two systematic searches were performed in PubMed (October 2018 - March 2019) using three sets of concepts ("lumbar spine", "load-sharing" and "motion segment components") followed by a complementary generic search. The segment overall response as well as the relative role of its constituents are markedly influenced by alterations in resection sequence, boundary conditions, geometry, loading characteristics (rate, magnitude, combinations and preloads), disc hydration, bone quality, posture and time (creep and cyclic). Structural transection order affects both findings and conclusions not only in force-control protocols but also in displacement-control loading regimes. Disc degeneration, endplate fracture and surgical resections significantly alter load transmission in the lumbar spine. In summary, in vitro and finite element model studies have together substantially improved our understanding of functional biomechanics (load-sharing) of human lumbar spine in normal and perturbed conditions acting as invaluable complementary tools in clinical applications.
人类腰椎运动节段由各种具有明显贡献的成分组成，对其整体力学反应有影响。通过采用实验和计算方法，许多研究已经研究了每个成分的相对作用，以及各种因素的影响，如边界初始条件、载荷大小-组合方向、载荷时间状态、预载荷、姿势、退变、故障和手术干预对载荷分配的影响。本文综述并批判性地讨论了关于健康、老化、退变和损伤的人类腰椎运动节段的载荷分配的体外和有限元模型研究的相关发现。在 PubMed 中进行了两次系统搜索（2018 年 10 月至 2019 年 3 月），使用三组概念（“腰椎”、“载荷分配”和“运动节段成分”），然后进行了补充的一般搜索。节段的整体反应及其组成成分的相对作用受到切除顺序、边界条件、几何形状、载荷特性（速率、大小、组合和预载荷）、椎间盘水合作用、骨质量、姿势和时间（蠕变和循环）的改变的显著影响。结构截断顺序不仅影响力控制方案，而且影响位移控制加载模式下的结果和结论。椎间盘退变、终板骨折和手术切除会显著改变腰椎的载荷传递。总之，体外和有限元模型研究共同极大地提高了我们对正常和受扰条件下人类腰椎功能生物力学（载荷分配）的理解，作为临床应用中宝贵的补充工具。
