Table 2.

Mechanical Properties of Intact and Discectomy Intervertebral Discs Under Axial Compression, Axial Tension, Bending (i.e., Flexion, Extension, and Lateral Bending), Axial Torsion, and Shear

	Intact	Discectomy
Compressive modulus (MPa)
ND	10–20	7–14
D	5–12	8
—	4–25	2–29
Tension modulus (MPa)
ND	2.6–3.5
—	n/a	2.5
Bending stiffness (N × mm/deg)
Flexion	500–2200
Extension	1100–2500
Lateral	1800–3800
Torsional stiffness (N × mm/deg)
ND	700–1100	200–1000
D	600–1800	500–1400
Shear stiffness (N/mm)
Lateral	40–300	200–265
Anterior–posterior	20–300	165–500

Values for ND and D discs are separated when noted in the respective studies. “—” Represents pooled data for ND and D discs reported. Values were compiled from data reported in Refs.^{3,38,57,66–71,91,151}