Table 1.

Comparison of the concave/convex ratios of SI–ASIS in patients with AIS

		Concave/convex ratios of SI–ASIS
Curve type	N	Mean ± SD	P-value
All	42	0.97 ± 0.03	< 0.0001*
Group 1	12	0.98 ± 0.04	0.12
Group 2	8	0.98 ± 0.03	0.06
Group 3	22	0.97 ± 0.03	0.001*

Group 1: thoracic curve group; Group 2: thoracolumbar/lumbar curve group; Group 3: double curve group.

SI–ASIS, the distance between two plumb lines through the inferior ilium at the sacroiliac joint (SI) and the anterior superior iliac spine (ASIS).

^*P (mean compared with 1).