Biomechanical Comparison of Multilevel Lumbar Instrumented Fusions in Adult Spinal Deformity According to the Upper and Lower Fusion Levels: A Finite Element Analysis

Table 1

Material properties of the spine.

Materials	Young’s modulus (Mpa)	Poisson’s ratio
Ilium (cortical)	17,000	0.3
Ilium (cancellous)	132	0.2
Sacrum (cortical)	6140	0.3
Sacrum (cancellous)	1400	0.3
Vertebral body (cortical)	12,000	0.3
Vertebral body (cancellous)	100	0.3
Posterior elements	3500	0.25
Annulus fiber	450
Annulus matrix	4.2	0.45
Nucleus pulposus	1	0.499
Endplate	100	0.3