摘要
背景:Topping-off技术通过将腰椎融合和棘突间动态内固定系统(Coflex)结合,在实现充分减压的同时也能够对相邻节段予以保护。目前将Topping-off技术应用于腰骶区需要融合同时相邻节段存在退变的年轻患者的相关力学研究尚未见报道。目的:建立腰骶交界区Topping-off有限元模型,分析邻近节段生物力学及全腰椎活动度的变化趋势。方法:随机选择1名健康年轻男性志愿者,既往无腰部外伤史及腰痛病史,经签署志愿同意书后,行薄层CT扫描,获取影像学资料。将图像信息导入计算机,依次通过Mimics、Geomagic Studio 12.0、HyperMesh、Abaqus对图像信息进行分析建立全腰椎模型,即健康组模型。验证模型的有效性后,在健康组模型的基础上改变L4-S1椎间盘材料属性建立椎间盘中度退变模型,并在退变模型的基础上分别建立融合模型和Topping-off模型。然后分别计算4组模型在施加400 N的预载荷和10 N m的扭转力矩后L2-L5节段活动度变化趋势及L4/L5椎间盘、髓核以及关节突关节的应力变化。结果与结论:①Topping-off模型与融合模型腰椎活动度较退变模型减小,且Topping-off模型比融合模型减小更明显;②融合模型术后L4-L5活动度较退变模型显著增加,L2/L3、L3/L4节段活动度相比退变模型并无明显改变;Topping-off模型L4-L5活动度较退变模型减小,L2/L3、L3/L4节段活动度相比退变模型在前屈及后伸体位下均有一定程度增加;③相比退变模型,融合模型L4-L5节段在前屈、后伸、左旋、左侧弯4个体位下,椎间盘、髓核、关节突关节应力均增大,而Topping-off模型纤维应力在4个体位下均降低;④说明Topping-off技术不仅能够降低上位相邻节段椎间盘、髓核和关节突的关节应力,而且能够减少相邻节段过度活动,增加上位其他节段的活动度,进而在代偿腰椎活动度的同时延缓相邻节段退变。
BACKGROUND:The Topping-off technique,which combines lumbar fusion with the dynamic internal fixation system(Coflex),can not only reduce the pressure,but also protect the adjacent segments.There is no relevant mechanical analysis performed on the rationality of the application of Topping-off technique to young patients with the need for fusion on the lumbosacral region and adjacent degenerated segments.OBJECTIVE:To establish a finite element model of Topping-off surgery on the lumbosacral junction and to analyze the biomechanical changes of the adjacent segments and the range of motion trend of the lumbar spine.METHODS:A healthy young male volunteer with no previous history of low back pain or congenital malformations was randomly selected for thin-slice CT scanning after signed the informed consent.The image information was imported into the computer and the whole lumbar spine model as the healthy group model was established by analyzing the image information through Mimics,Geomagic Studio 12.0,HyperMesh and Abaqus successively.After verifying the effectiveness of the model,the moderate degeneration model of intervertebral disc was established by changing the material properties of L4-S1 discs on the basis of the healthy model,and the fusion model and Topping-off model were respectively established on the basis of the degeneration model.After applying 400 N compressive load and 10 N m momentum to the four groups of models,the variation trends of range of motion from L2 to L5 and the stress changes of L4/L5 intervertebral disc,nucleus pulposus and facet joints were calculated respectively.RESULTS AND CONCLUSION:(1)Compared with the degeneration model,the lumbar range of motion of Topping-off model and fusion model decreased,and the Topping-off model decreased more significantly than the fusion model.(2)The range of motion of fusion model L4-L5 increased significantly and the range of motion of L2/L3 and L3/L4 segments did not change significantly.Compared with the degeneration model,the L4-L5 range of motion of Topping-off model decreased,and range of motion of the L2/L3 and L3/L4 levels increased to some extent in the flexion and extension positions.(3)Compared with the degeneration model,the stress on the disc,nucleus pulposus and facet joint of the fusion model L4-L5 increased in four positions of flexion,extension,rotation and bending,while the fiber stress on the Topping-off model decreased significantly in all four positions.(4)These results suggest that Topping-off technology can not only reduce the stress on the upper adjacent degenerative intervertebral disc,nucleus pulposus and facet joints,but also reduce the hyperactivity of the adjacent segments and increase the range of motion of other upper segments,thereby compensating the lumbar spine mobility and delaying the degeneration of upper adjacent segments.
作者
曹亮亮
徐建广
梅伟
Cao Liangliang;Xu Jianguang;Mei Wei(Zhengzhou Orthopedics Hospital,Zhengzhou 450052,Henan Province,China;Sixth People’s Hospital Affiliated to Shanghai Jiao Tong University,Shanghai 200000,China)
出处
《中国组织工程研究》
CAS
北大核心
2020年第12期1905-1910,共6页
Chinese Journal of Tissue Engineering Research
基金
上海市市级医院新兴前沿技术联合攻关项目(SHDC12014102)，课题名称：棘突间动态固定系统防治腰椎间盘退变的规范化方案研究及推广应用，项目负责人：徐建广~~
