Coflex和X-STOP治疗腰椎管狭窄的生物力学性能  

Biomechanical properties of Coflex and X-STOP in treatment of lumbar spinal stenosis

作　　者：谷雪莲[1] 蔡方舟 胡方遒[1] 宋成利[1] 

机构地区：[1]上海理工大学教育部微创医疗器械工程研究中心,上海200093

出　　处：《医用生物力学》2015年第4期318-325,共8页Journal of Medical Biomechanics

基　　金：上海市专业学位研究生实践基地建设项目(1014308301)

摘　　要：目的分析棘突间撑开器Coflex和X—STOP在治疗腰椎管狭窄中的不同生物力学特性，为棘突问植入物的设计改进提供参考。方法依据1名正常志愿者中立位下螺旋cT扫描资料构建L2～5健康腰椎有限元模型、IA／5椎间盘轻度退变有限元模型、棘突撑开器X—STOP和Coflex的动态固定模型，并对4组模型分别模拟前屈、后伸、侧弯和轴向旋转，验证和对比分析活动度（rangeofmotion，ROM）的变化和应力在棘突和撑开器上的分布。结果与退变模型相比，Coflex和X—STOP有效限制退变节段后伸ROM-48．12％和-75．35％，Coflex还能限制前屈ROM-59．58％，侧弯和扭转ROM不受限制。Coflex和X—STOP减少椎间盘后伸时应力达-58．03％和-80．75％，Coflex在前屈时应力减少-52．84％。侧弯和扭转的ROM基本不受影响。Coflex最大应力发生在前届时U型弯处，X—STOP最大应力出现在扭转时左翼螺钉连接处。Coflex与腰椎接触最大应力发生在扭转时，为31．38MPa。X—STOP与腰椎接触最大应力发生在侧弯时，为46．86MPa。结论Coflex和X-STOP是治疗腰椎管狭窄的有效方法，均可以显著降低后伸ROM和椎间盘压力，对相邻节段无明显影响。Objective To analyze different biomechanical properties between Coflex and X-STOP device in the treatment of lumbar spinal stenosis （LSS）, and provide references for design improvement of interspinous process spacer. Methods Four finite element models, i. e., the 1.2-5 healthy segment model, the mild degener- ated L4/5 segment model, the X-STOP-fixed 1_4/5 segment model, the Coflex-fixed L4/5 segment model, were constructed based on the normal lumbar CT images of a volunteer, and the models under flexion, extension, lat- eral bending and axial rotation were simulated to compare range of motion （ROM） changes and stress distribu- tions on the spinous process and interspinous process spacer. Results X-STOP and Coflex decreased extension ROM by -48.12% and -75.35%, respectively, and released disc pressure by -58.03% and -80.75%, re- spectively. Coflex even restricted flexion ROM by -59.58% and reduced flexion disc pressure by -52.84%. No distinct changes appeared in lateral bending and axial rotation ROMs and disc pressure. The largest Von Mises stress appeared at the U-shape place during flexion in Coflex and at connection between left wing and screw dur- ing torsion in X-STOP, respectively. The largest contact pressure between Coflex and spinous process was 31.38 MPa during bending, and that between X-STOP and spinous process was 46.86 MPa during torsion. Con-clusions Both X-STOP and Coflex are an effective treatment for LSS, and can effectively restrict the ROM of ex- tension and reduce the disc pressure, without affecting the adjacent segments.

关 键 词：棘突间撑开器 腰椎管狭窄症 生物力学特性 椎间盘压力 

分 类 号：R318.01[医药卫生—生物医学工程]