TABLE II.

Flexion and Extension Rotation Range of Motion (in Degrees) During Dynamic Flexion-Extension^*

	C2/C3		C3/C4		C4/C5		C5/C6		C6/C7
Group	Flex	Ext	Flex	Ext	Flex	Ext	Flex	Ext	Flex	Ext
Control†	5.9 ± 2.4	4.2 ± 2.2	7.9 ± 3.6	6.3 ± 3.3	8.0 ± 2.6	7.9 ± 3.3	7.4 ± 2.9	7.3 ± 3.8	7.1 ± 3.9	5.4 ± 2.3
C5/C6 arthrodesis†	N/A	N/A	6.1 ± 3.1	7.1 ± 2.2	5.1 ± 3.7*	11.7 ± 4.1*	2.2 ± 1.1*	0.6 ± 1.4*	5.9 ± 3.1	6.7 ± 3.0
Difference	N/A	N/A	−1.8	0.8	−2.9	3.8	−5.2	−6.7	−1.2	1.3
95% CI‡	N/A	N/A	−4.5 to 0.9	−1.5 to 3.2	−5.3 to −0.5	0.9 to 6.6	−7.1 to −3.2	−9.2 to −4.1	−4.1 to 1.7	−1.1 to 3.6

^*No significant differences between flexion and extension ranges of motion were identified in the control group or arthrodesis group at any motion segment. The following significant differences between the control and arthrodesis groups were identified (marked by asterisks within the table): C4/C5 (extension): control < arthrodesis (p = 0.011); C4/C5 (flexion): control > arthrodesis (p = 0.019); C5/C6 (flexion): control > arthrodesis (p < 0.001); and C5/C6 (extension): control > arthrodesis (p < 0.001). N/A = not available.

^†The values are given as the mean and standard deviation.

^‡The 95% confidence interval of the difference between groups.