Table 2 Summary of the material properties used in our finite element models

Bone

Linear-elastic

ρ = 1.067 * HU + 131 (g/cm³)

23

E = 0.09882 ρ^1.56 (MPa)

Intervertebral disc

Mooney-Rivlin formulation (MPa)

c₁₀

c₀₁

D ₁

NUC

Hyper-elastic

0.12

0.09

1

25

ANN

0.56

0.14

1

26

Ligaments

Ogden-3 formulation (MPa)

27, 28

ALL

Hyper-elastic

(See Table 3)

SSL

ISL

PLL

Hyper-elastic

(See Table 3)

LF

IL

Hyper-elastic

(See Table 3)

Facet Joint

Linear-elastic

Spring elements: E=250 (MPa)

29

Modulus of Elasticity

Poisson’s Ratio (μ)

Graft bone

Linear-elastic

100 (MPa)

0.2

10

AIB

Linear-elastic

1500 (MPa)

0.3

24

PEEK

Linear-elastic

3500 (MPa)

0.3

20

Titanium

Linear-elastic

110 (GPa)

0.3

11