不同矢状角度置入椎弓根螺钉的拔钉生物力学研究

Biomechanical Study of Pull-out Force on Pedicle Screws of Different Sagittal Angles

目的观察椎弓根螺钉不同矢状成角置入后单个椎体的拔钉生物力学特点,为临床置钉提供理论依据。方法采用猪新鲜L1共12个椎体标本,将24侧椎弓根分三组,按不同矢状成角0°组、10°组、-20°组置入椎弓根螺钉,测出最大轴向拔出力。结果-20°组椎弓根螺钉拔出力及拔出能量最大,0°组最小,10°组界于二者之间;三组之间最大拔出力及拔出能量两两比较P<0.05,提示各组之间差异均有统计学意义。结论矢状面成角置钉对螺钉的把持力大于0°角置钉,随置钉角度的增加,螺钉把持力也增大。

Objective To study the biomechanics of pull-out force on the pedicle screws after the screws inserted into the pedicle of vertebral arch at different angles in vertical plane, and provide the basis for the clinical practice. Methods The pedicle of vertebral arch （24 sides） were randomly selected into 3 groups： group A, 0° in the vertical plane; group B, 10° in the vertical plane and group C, -20° in the vertical plane. The maximum axial direction extraction force was examined. Results The maximum axial direction extraction force appeared in group C （-20°）, while the minimum value appeared in group A （0°）. In group B（10°）, the measurement value was between the above 2 groups. The differences were significant （P〈0.05）. Conclusion When the screws are inserted into the pedicle of vertebral arch angulated, the holding force will be greater than 0° group. The holding force is increased as the angle is augmentated.