Table 2.

Comparisons of clinical data before and after surgery between the two groups

Items	CR Group	PR Group	p
Surgical.time/min	146.2 ± 35.8	134.4 ± 30.2	0.224
Bleeding/mL	156.2 ± 89.0	120.4 ± 44.3	0.075
ADI /mm
Before surgery	6.5 ± 1.9	7.3 ± 2.2	0.155
At discharge	2.3 ± 0.9	1.5 ± 1.0	0.012
Final follow-up	2.3 ± 0.8	1.6 ± 0.7	0.001
P1	< 0.001	< 0.001	/
P2	< 0.001	< 0.001	/
JOA/score
Before surgery	13.0 (15.0–11.0)	12.0 (14.0–11.0)	0.418
At discharge	15.0 (16.0–13.0)	15.0 (16.0–13.0)	0.416
Final follow-up	16.0 (17.0–14.0)	16.0 (17.0–16.0)	0.201
P1	< 0.001	< 0.001	/
P2	< 0.001	< 0.001	/
VAS/score
Before surgery	4.0(5.0-2.5)	4.0(5.0–2.0)	0.832
At discharge	1.0(2.0-0.5)	1.0(2.0–0)	0.583
Final follow-up	0(1.0–0)	0(1.0–0)	0.541
P1	< 0.001	< 0.001	/
P2	< 0.001	< 0.001	/
NDI/%
Before operation	58.0(61.0–54.0)	58.0(60.0–56.0)	0.975
At discharge	24.0(28.0–22.0)	26.0(28.0–24.0)	0.216
Final follow-up	2.0(4.0–0)	0(4.0–0)	0.365
P1	< 0.001	< 0.001	/
P2	< 0.001	< 0.001	/
Complications/n(%)
Bone non-fusion	0	1 (3.7%)	> 0.999
Bony fusion/n(%)
3-month follow-up	17 (80.9%)	14 (51.6%)	0.037
6-month follow-up	19 (90.5%)	23 (85.2%)	0.683
12-month follow-up	21 (100%)	26 (96.3%)	> 0.999

*Values are expressed as mean ± standard error or the median plus the interquartile range, with the range in parentheses

CR = Crossed rod; PR = Parallel rod; ADI = Atlas-dens intervals; JOA = Japanese Orthopaedic Association score; VAS = visual analogue scale; NDI = Neck Disability Index; P1 represents the statistical difference between preoperative and postoperative changes in observed values; P2 represents the statistical difference between preoperative and at the final follow-up changes in observed values