摘要：目的：研究脊柱椎弓根螺钉并横向牵引装置的把持力与外倾角的关系。方法：将18只成人腰椎干燥标本随机分为三组，每组6只，分别以5°、15°、30°的外倾角打入直径5.5mm的椎弓根螺钉，钉尾用横向牵引装置连接，测定把持力。结果：在5°～30°的范围内，随着外倾角的增加，椎弓根螺钉的把持力增加，但对椎体的应力也增加。结论：在应用经椎弓根螺钉内固定并加用横向牵引装置时，适当增加外倾角，可增大螺钉的把持力，提高固定强度，外倾角过大则易对椎体造成破坏。

    关键词：外倾角；椎弓根螺钉；横向牵引装置；内固定；生物力学；把持力

    Biomechanical Evaluation of Pedicle Screw Internal Fixation Effects with Different Extraversion Angle

    CHEN Qun,JIN Zhen-shuai,CAO Xiao-jian,et al

    (The First Affiliated Hospital of Nanjing Medical University, Jiangsu Nanjing 210029, China)

    Abstract：Objective: To study the correlations of the pullout strength of pedicle screw with device for transverse traction and extraversion angle.Methods: 18 adulted human lumber vertebrae were randomly divided into 3 groups,6 lumber vertebrae for each group. pedicle screws (diameter 5.5mm)with device for transverse traction were inserted into with extraversion angle 5°,15°,30° for pullout test. Results: The pullout strength were increased when the extraversion angle were augmented from 5o to 30o. meanwhile, the vertebral stress force increased too.Conclusion: Results suggested that the pedicle screws with device for transverse traction might have better fixation effects when extraversion angle were augmented, but the increased stress force might damage vertebrae. ......