With one S1 pedicle screw fixation,the average stiffness was 203N/mm for compression,147N/mm for tension,and 2Nm/deg. for torsion. With two screw fixation,the average stiffnesses increased to 255N/mm(126%),185N/mm(126%) and 2 4Nm/deg.

• 结果 :单钉固定的压缩、拉伸和扭转刚度分别为 2 0 3N/mm、1 4 7N/mm和 2 0Nm/deg ,双钉分别为 2 5 5N/mm、1 85N/mm和 2 4Nm/deg ,两者刚度的差异均有显著性。