Table 1 Basic information of patients
| Â | Group A | Group B | Standardized differences |
|---|---|---|---|
Cases | 311 | 259 | Â |
Age | 50.3 ± 12.7 | 53.2 ± 12.1 | 0.23 |
Gender | Â | Â | 0.02 |
 Male [n (%)] | 155 (49.84%) | 126 (48.65%) |  |
 Female [n (%)] | 156 (50.16%) | 133 (51.35%) |  |
BMI (kg/m2) | 24.2 ± 3.2 | 24.07 ± 3.0 | 0.04 |
Disease distribution | Â | Â | 0.36 |
 Lumbar disc herniation [n (%)] | 251 (80.71%) | 197 (76.06%) |  |
 Lumbar spinal stenosis [n (%)] | 33 (10.61%) | 54 (20.85%) |  |
 Lumbar degenerative spondylolisthesis [n (%)] | 27 (8.68%) | 8 (3.09%) |  |
Segment distribution | Â | Â | 0.28 |
 L1/2 [n (%)] | 22 (7.07%) | 30 (11.58%) |  |
 L2/3 [n (%)] | 68 (21.86%) | 63 (24.32%) |  |
 L3/4 [n (%)] | 68 (21.86%) | 46 (17.76%) |  |
 L4/5 [n (%)] | 92 (29.58%) | 54 (20.86%) |  |
 L5/S1 [n (%)] | 61 (19.61%) | 66 (25.48%) |  |