腰椎长节段内固定不同曲度连接棒的生物力学分析  

Biomechanical analysis of long segments internal fixation with different bending rod in lumbar spine

作　　者：孟猛 李忠海[1] Meng Meng;Li Zhonghai(Department of Orthopaedics,the First Affiliated Hospital of Dalian Medical University,Dalian 116011,China)

机构地区：[1]大连医科大学附属第一医院骨科,116011

出　　处：《中华实验外科杂志》2022年第7期1256-1259,共4页Chinese Journal of Experimental Surgery

基　　金：辽宁省"兴辽英才计划"项目资助(XLYC1807131)。

摘　　要：目的通过有限元方法分析腰椎长节段椎弓根螺钉内固定时连接棒曲度差异对内固定及椎间盘应力的影响。方法基于大连医科大学附属第一医院1名正常成年志愿者L1~L5节段的CT图像建立腰椎有限元模型。根据连接棒曲度与腰椎正常生理曲度的关系分为直棒组、正常生理曲度棒组及大曲度棒组。比较在腰椎前屈、后伸,左、右侧弯,左、右旋转等6种工况下3组模型的内固定、L1/L2椎间盘和L4/L5椎间盘的最大应力及应力分布。结果在所有不同工况下,椎弓根螺钉、连接棒在直棒组中最大应力分别为61.64、179.28 Mpa;在生理曲度棒组中分别为40.52、66.33 Mpa;在大曲度棒组中分别为45.99、73.37 Mpa。生理曲度棒组内固定最大应力小于直棒组和大曲度棒组。3组模型中内固定的应力均主要分布于螺钉与椎体后壁交界处、钉尾处和钉棒结合处。直棒组、生理曲度棒组、大曲度棒组L1/L2椎间盘最大应力分别为9.20、9.39、9.18 Mpa;L4/L5椎间盘最大应力分别为5.08、5.01、4.88 Mpa。3组模型椎间盘最大应力及分布无明显差异。结论生理曲度连接棒可有效降低椎弓根螺钉和连接棒应力,降低内固定断裂以及钉棒松动的风险。Objective The finite element method was used to analyze the influence of the curvature of the connecting rod on internal fixation and intervertebral disc stress in long segment pedicle screw fixation.Methods Based on CT images of L1-L5 selected from the First Affiliated Hospital of Dalian Medical University,the finite element model was established.According to the relationship between connecting rod curvature and normal physiological curvature,the model was divided into straight rod group,normal physiological curvature rod group,and large curvature rod group.The maximum stress of L1/L2 and L4/L5 intervertebral disc and the stress distribution of three models were compared under six working conditions of lumbar flexion and extension,left and right bending,and left and right rotation.Results The maximum stress of pedicle screw and connecting rod in straight rod group was 61.64 Mpa and 179.28 Mpa,40.52 Mpa and 66.33 Mpa in physiological curve bar group,45.99 Mpa and 73.37 Mpa in large curvature bar group.In three models,the stress of internal fixation was mainly distributed at the junction of screw and posterior wall of vertebral body,the screw tail and the joint of screw rod.The maximum stress of L1/L2 disc in straight bar group,physiological bend bar group and large bend bar group was 9.20,9.39 and 9.18 Mpa.The maximum stress of L4/L5 disc was 5.08,5.01 and 4.88 Mpa.There was no significant difference in the maximum stress and distribution of L1/L2 and L4/L5 intervertebral discs among the three groups.Conclusion The pedicle screws and connecting rods in the physiologically curved bar model had less stress and less risk of internal fixation fracture and rod loosening.

关 键 词：腰椎 内固定 有限元分析 

分 类 号：R687.3[医药卫生—骨科学] R318.01[医药卫生—外科学]