Biomechanical Investigation of the Posterior Pedicle Screw Fixation System at Level L4-L5 Lumbar Segment with Traditional and Cortical Trajectories: A Finite Element Study

Table 1

Material properties of each component in the FE models.

Element	Element type	Modulus of elasticity (MPa)	Poisson ratio	Density (ton/mm^3)
Vertebral cortical bone	C3D10M	12000	0.30	1.9e − 9
Vertebral cancellous bone	C3D10M	100	0.2	0.7e − 9
Annulus fibrosus and nucleus pulposus	C3D10M	3.2	0.45	0.9e − 9
Screw and rod	C3D10M	110000	0.3	4.5e − 9