Table 2.

Comparison of radiographic parameters between the two groups

	4S group	6S group	P value
LL (°)
Pre	52.30 ± 7.94	53.02 ± 8.55	0.705
1 month	57.49 ± 6.51*	60.17 ± 7.10*	0.090
6 months	57.30 ± 6.45*	60.08 ± 7.06*	0.077
Final	56.35 ± 6.15*	59.55 ± 6.84*	0.036
SL (°)
pre	16.32 ± 4.83	16.04 ± 4.54	0.999
1 month	24.37 ± 2.68*	25.21 ± 2.95*	0.197
6 months	24.26 ± 2.60*	25.16 ± 2.91*	0.160
Final	23.49 ± 2.34*	24.88 ± 2.85*	0.023
PI (°)
Pre	61.84 ± 9.35	62.64 ± 10.03	0.721
1 month	62.30 ± 9.02	62.44 ± 9.83	0.949
6 months	62.35 ± 9.07	62.33 ± 9.91	0.992
Final	62.22 ± 9.04	62.41 ± 9.86	0.931
PT (°)
Pre	21.27 ± 4.00	20.85 ± 5.05	0.690
1 month	16.41 ± 4.23*	15.03 ± 4.27*	0.161
6 months	16.62 ± 4.04*	15.21 ± 4.11*	0.136
Final	17.35 ± 3.98*	15.49 ± 4.05*	0.047
SS (°)
Pre	40.76 ± 10.19	41.87 ± 10.18	0.532
1 month	46.51 ± 9.71*	47.46 ± 10.37*	0.681
6 months	46.11 ± 9.48*	47.15 ± 10.35*	0.650
Final	45.27 ± 9.26*	46.85 ± 10.34*	0.486
SVA (mm)
Pre	54.43 ± 46.21	56.52 ± 45.76	0.844
1 month	31.26 ± 43.78*	27.81 ± 42.98*	0.730
6 months	32.98 ± 43.85*	28.01 ± 43.07*	0.620
Final	33.71 ± 44.64*	28.98 ± 44.12*	0.644
SD (%)
Pre	22.40 ± 7.20	23.18 ± 7.53	0.646
1 month	6.67 ± 2.88*	5.23 ± 2.12*	0.015
6 months	7.03 ± 2.54*	5.59 ± 1.89*	0.009
Final	8.08 ± 2.53*	6.08 ± 2.07*	0.003
Slip correction rate (%)	68.86 ± 15.67	77.25 ± 7.4	0.004

LL Lumbar lordosis, SL Segmental lordosis, PI Pelvic incidence, PT Pelvic tilt, SS Sacral slope, SD Slippage degree, SVA Sagittal vertical axis

Slip correction rate (%) = [(preoperative slip percentage – postoperative slip percentage)/ (preoperative slip percentage) × 100%]

1 month: one month after surgery, 6 months: six months after surgery, FINAL: final follow-up

*Statistically significant compared with the preoperative value, p < 0.05

Bold represents there is statistical significance between the groups, p < 0.05