Mid-long-term follow-up of operated level kinematics after single-level artificial cervical disc replacement with Bryan disc

Table 4 Correlations between COR and other follow-up data at the last follow-up

Parameters	COR (X) (%)		COR (Y) (%)
Parameters	r value	P value	r value	P value
Age (years)	0.244	0.201	− 0.276	0.147
Follow-up period (months)	0.003	0.989	0.038	0.845
mJOA	− 0.266	0.163	0.213	0.268
VAS (neck pain)	0.036	0.853	0.025	0.897
VAS (arm pain)	0.167	0.388	0.042	0.831
NDI	0.277	0.146	− 0.083	0.668
mJOA improvement rate (%)	− 0.279	0.143	0.184	0.340
VAS (neck pain) improvement rate (%)	0.001	0.998	− 0.068	0.726
VAS (arm pain) improvement rate (%)	− 0.143	0.461	− 0.032	0.868
NDI improvement rate (%)	− 0.354	0.060	− 0.075	0.699
ROM (overall cervical) (°)	− 0.003	0.987	− 0.182	0.346
Lordosis angle (overall cervical) (°)	− 0.108	0.577	− 0.002	0.991
Lordosis angle (operated level) (°)	0.162	0.402	0.132	0.495
ROM (operated level) (°)	− 0.014	0.942	− 0.622*	< 0.001
SROM (°)	0.150	0.438	− 0.078	0.688
IROM (°)	− 0.046	0.811	− 0.269	0.157
Translation (operated level) (mm)	0.263	0.169	− 0.767*	< 0.001

COR, center of rotation; mJOA, modified Japanese Orthopedic Association; VAS, visual analogue scale; NDI, Neck Disability Index; ROM, range of motion; SROM, superior range of motion; IROM, inferior range of motion
^*P < 0.05, significant correlation between two parameters

ISSN: 1749-799X