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Table 2 Vertical displacement and maximum von Mises stress distribution of five groups

From: S2-alar-iliac screw and S1 pedicle screw fixation for the treatment of non-osteoporotic sacral fractures: a finite element study

Groups

Vertical displacement (mm)*

The maximum von Mises stress in the implant (MPa)

The maximum von Mises stress in the bone around the screw (MPa)

Main screw**

Secondary screw

LPF

0.9861

97.354

26.810

10.402

TIFI

1.0694

65.580

21.390

0.638

SIS

0.7119

165.770

31.955

–

S2AI-S1

0.6864

55.262

26.695

26.304

S2AI-CS1

0.7491

63.589

36.839

7.715

  1. *The vertical displacement (Z-axis) of the center point of the upper surface of the S1 vertebral body
  2. **In the LPF and TIFI groups, the main screw is the right iliac screw, while in the S2AI-S1 and S2AI-CS1 groups, the main screw is the S2AI screw. The screws in each group except one main screw are secondary screws