Sequential sagittal alignment changes in the cervical spine after occipitocervical fusion

Table 2 Pearson product moment coefficient (Pearson’s r value) between O-C2 angle and C2-7 angle and other parameters in the occipitocervical fusion and control groups

OCF (n = 84)	r value	P value	Control (n = 42)	r value	P value
O-C2a
O-EAa	0.039	0.728	O-EAa	0.309	0.046
C2Ta	-0.872	0.000	C2Ta	-0.802	0.000
C2-7a	-0.585	0.000	C2-7a	-0.385	0.012
T1 slope	-0.174	0.214	T1 slope	-0.080	0.615
C2-7 SVA	0.067	0.545	C2-7 SVA	0.331	0.032
PIA	0.757	0.000	PIA	0.579	0.000
C2-7a
O-C2a	-0.585	0.000	O-C2a	-0.385	0.012
O-EAa	0.023	0.837	O-EAa	-0.100	0.530
C2Ta	0.540	0.000	C2Ta	0.326	0.035
T1 slope	0.490	0.000	T1 slope	0.523	0.000
C2-7 SVA	-0.013	0.909	C2-7 SVA	-0.239	0.127
PIA	-0.546	0.000	PIA	-0.156	0.324

O-C2a: O-C2 angle; O-EAa: Occipital and external acoustic meatus to axis angle; C2Ta: C2 tilting angle; C2-7a: C2-7 angle; SVA: Sagittal vertical axis; PIA: Pharyngeal inlet angle.