(a) LS-INT

PLIF model

(b) LS-PEEK

(c) LS-Titanium

P value

(Ⅱ) Flexion

Drucker-Prager stress (MPa)

0.17 ±0.093

1.4 ± 0.74

2.7 ± 1.5

0.002**

Strain energy density (KJ/m³)

0.00078 ±0.0016

0.055 ± 0.062

0.25 ± 0.25

0.003**

Maximum principal stress (MPa)

0.10 ±0.059

0.76 ± 0.47

1.2 ± 1.3

0.12

Minimum principal strain (×1.0E−4)

−0.026 ±0.035

−0.28 ± 0.30

−0.65 ± 0.43

0.003**

(Ⅲ) Extension

Drucker-Prager stress (MPa)

0.23 ± 0.14

1.0 ± 0.29

1.5 ± 0.37

<0.001**

Strain energy density (KJ/m3)

0.0018 ± 0.0031

0.035 ± 0.047

0.076 ± 0.088

0.076

Maximum principal stress (MPa)

0.047 ± 0.10

0.27 ± 0.20

0.70 ± 0.32

<0.001**

Minimum principal strain (×1.0E-4)

−0.083 ± 0.046

−0.35 ± 0.10

−0.43 ± 0.11

0.027*