Table 1 Patients characteristics

 Age (years)

52.1 ± 12.1

54.5 ± 13.7

0.525

 Female gender^a

16 (57.1%)

15 (57.7%)

0.967

 Body mass index (kg/m², BMI)

23.0 ± 2.6

24.0 ± 2.7

0.663

 ASA class ^c

1.2 ± 0.42

1.3 ± 0.47

0.438

 Spondylolisthesis^a

12 (42.9%)

14 (53.8%)

0.419

 Lumbar instability

10 (35.7%)

6 (23.1%)

0.310

 Lumbar spinal stenosis^b

4 (14.3%)

5 (19.2%)

0.626

 Lumbar disc herniation^a

2 (7.1%)

1 (3.8%)

0.597

 Range

13–59

12–59

 Mean

39.5 ± 6.1

37.0 ± 6.7

0.544