The biological basis of degenerative disc disease: proteomic and biomechanical analysis of the canine intervertebral disc

Table 2 Analysis of angular displacements during the application of 1 Nm moment in flexion and extension and axial rotation motions

Movement		CD canines	NCD canines	p value	95 % CI
Flexion	Zero crossing displacement	0.01° (±0.02)	0.01° (±0.03)	0.850	−0.003, 0.024
	Halfway from zero to peak displacement	1.16° (±0.39)	0.73° (±0.16)	0.000	0.584, 0.876
	Peak displacement	2.29° (±0.79)	1.44° (±0.33)	0.000	1.150, 1.735
	Halfway from peak to zero displacement	1.15° (±0.39)	0.72° (±0.16)	0.000	0.573, 0.866
Extension	Zero crossing displacement	0.00° (±0.00)	0.00° (±0.00)	0.753	−0.001, 0.002
	Halfway from zero to peak displacement	−0.82° (±0.28)	−0.44° (±0.19)	0.000	−0.554, −0.220
	Peak displacement	−1.61° (±0.53)	−0.86° (±0.38)	0.000	−1.063, −0.434
	Halfway from peak to zero displacement	−0.78° (±0.27)	−0.43° (±0.20)	0.000	−0.514, −0.185
Right axial rotation	Zero crossing displacement	0.00° (±0.01)	0.00° (±0.03)	0.358	−0.002, 0.001
	Halfway from zero to peak displacement	0.55° (±0.25)	0.37° (±0.17)	0.016	0.036, 0.334
	Peak displacement	1.10° (±0.50)	0.73° (±0.35)	0.017	0.071, 0.663
	Halfway from peak to zero displacement	0.55° (±0.25)	0.36° (±0.17)	0.017	0.035, 0.331
Left axial rotation	Zero crossing displacement	0.00° (±0.01)	0.00° (±0.00)	0.492	−0.001, 0.001
	Halfway from zero to peak displacement	−0.60° (±0.20)	−0.38° (±0.24)	0.007	−0.374, −0.066
	Peak displacement	−1.20° (±0.41)	−0.73° (±0.48)	0.003	−0.778, −0.172
	Halfway from peak to zero displacement	−0.56° (±0.21)	−0.34° (±0.22)	0.005	−0.366, −0.069

CD chondrodystrophic, CI confidence interval, NCD Non-chondrodystrophic
Statistically significant differences between the NCD and CD motion segments in both flexion and extension and axial rotation motions are observed, indicating that the CD motion segments incur greater displacement (decreased stiffness) than the NCD motion segments
p < 0.05 was considered significant