Table 1.

Effect of reducing postoperative IV rotation on rASD

	Rotation angle of IV			rASD	N-rASD	Ratio	P
Total		Reduced		8	33	19.5%	0.004*
		Not reduced		33	37	47.1%
Total		Fused to S1	Reduced	2	14	12.5%	0.004*
			Not reduced	12	8	60%
		No fused to S1	Reduced	6	19	24%	0.125
			Not reduced	21	29	42%
Single level		Reduced		4	25	13.8%	0.048*
		Not reduced		14	26	35.0%
≥ 2 levels		Reduced		4	8	33.3%	0.078
		Not reduced		19	11	63.3%

IV, Instrumented vertebrae

*, Represents a significant difference between the two groups(P<0.05)