关键词: 生物力学;内固定器;对照临床试验

    摘 要:目的 了解不同形状螺纹的椎弓根螺钉在椎弓根内的拔出力的大小，给临床应用不同类型的经椎弓根内固定器提供实验依据. 方法 采用4种形状螺纹的椎弓根螺钉，分别在椎弓根内及椎体松质骨中进行拔出试验，观察其拔出力的大小及位移情况. 结果 在椎弓根内，Diapason的拔出力最大(1265±157)N(P<0.01)，CCD(913±85)N(P>0.05)及Dick(922±142)N次之，AF(648±68)N(P<0.01)的拔出力最小.而在松质骨内，Diapason(858±81)N(P<0.01)及CCD(816±23)N(P<0.01)则无差别，AF(511±20)N(P=0.025)其次，Dick(447±28)N的拔出力最小.最大拔出力下降50%时，CCD在椎弓根内的位移松动最大，AF与Dick其次，Diapason最少. 结论 Diapason外锥螺纹式的螺钉拔出力最大，临床上应尽可能地使用此种结构的内固定器.

    Biomechanics of pullout testing on the different threaded form of pedicle screws

    PAN Xian-Ming TAN Ying-Jun ZHANG Bo QUAN Yi HU Xiu-De HUANG Gang LI Yan CHEN Meng-Shi

    1 Department of Orthopedics，General Hospital of Chengdu Command Area of Chinese PLA，Chengdu610083，China，

    2 Mechanical Laboratory of Sichuan University，Chengdu610083，China

    Keywords:biomechanics;internal fixators;controlled clini-cal trials

    Abstract:AIM To study the pullout force of pedicle screws with different forms of thread and to supply the experiment data for the clinical application of transpedicular internal fixa┐tors.METHODS The pullout force scale and migration were observed when pedicle screws with four different forms of thread were pulled out from pedicle and cancellous bone.RESULTS In pedicle ......