Table 1.

Demographic and baseline data of patients with lumbar spinal stenosis

Variables	Total	Stenosis group (n = 23)	Spondylolisthesis group (n = 15)	Statistics	P
Age (years)	53.4 ± 5.8	52.2 ± 6.1	55.3 ± 5.0	1.64*	0.10
Gender (male/female), n	23/15	14/9	9/6	0.01†	0.96
Follow-up time (months)	78.9 ± 6.9	79.0 ± 7.5	78.7 ± 6.0	0.13*	0.90
Operating levels, n
Single level	28	17	11	0.01†	0.97
Two levels	10	6	4
ROM (°)
Stabilized segment	7.8 ± 2.4	7.6 ± 2.5	8.2 ± 2.3	0.75*	0.46
The upper adjacent segment	8.3 ± 2.4	8.6 ± 2.7	7.7 ± 2.0	1.11*	0.28
Disc height (mm)
Stabilized segment	11.9 ± 2.1	12.1 ± 2.1	11.7 ± 2.2	0.56*	0.58
Upper adjacent segment	12.4 ± 1.8	12.4 ± 1.7	12.5 ± 2.1	0.16*	0.87
Surgical duration (min)	120.3 ± 24.4	117.6 ± 26.6	124.3 ± 20.9	0.82*	0.39
Intraoperative blood loss (ml)	279.2 ± 73.6	270.0 ± 82.2	293.3 ± 57.8	0.95*	0.35

*Independent two-sample t-test; ^†Chi-square test. Values are presented as the mean ± standard deviation or n. ROM: Range of motion.