Table 1.

Biomechanical demands for an AF repair: healthy and degenerative properties of the human lumbar disc.

	Property	Disc Grade	Property Range	Reference
Organ Level/ Motion Segment (in situ testing)	Disc height	Healthy	11.1 ±2.5 mm 11.3 ±0.3 mm	(Chen and Wei, 2009) (O’Connell et al., 2007)
		Degenerative	9.2 ±2.9 mm (spondylolisthetic disc height)	(Chen and Wei, 2009)
	Intradiscal pressure	Healthy	0.5 MPa (leakage pressure) 1.9 MPa (300 N load pressure) Single patient 0.1–2.3 MPa	(Panjabi et al., 1988) (Adams et al., 1996) (Wilke et al., 1999)
		Degenerative	0.2 MPa (leakage pressure) 1.3 MPa (300 N load pressure)	(Panjabi et al., 1988) (Adams et al., 1996)
	Torsional mechanics	Healthy	0.7° – 0.8° (with 8° pelvic rotation) 3°max axial rotation 3.18 ±0.89 Nm/°	(Blankenbaker et al., 2006) (Haughton et al., 2002) (Costi et al., 2007) (Showalter et al., 2012)
		Degenerative	1.8° – 3.2° (with 8° pelvic rotation)	(Blankenbaker et al., 2006) (Haughton et al., 2002)
Tissue Level (in vitro testing)	Compressive (confined compression)	Healthy	0.56 ±0.21 MPa (HA, aggregate modulus)	(Iatridis et al., 1998)
		Degenerative	1.10 ±0.53 MPa (HA, aggregate modulus)	(Iatridis Et Al., 1998)
	Tensile (circumferential samples)	Healthy	12.7 MPa (E, tensile modulus)	(Acaroglu et al., 1995)
		Degenerative	9.4 MPa (E, tensile modulus)	(Acaroglu et al., 1995)
	Shear	Healthy	25 <Geq (kPa)<110	(Iatridis et al., 1999)
		Degenerative	25 <Geq (kPa)<140	(Iatridis et al., 1999)