Table 1 Patients’ data
N | 176 |
|---|---|
Age (years old) | 65.5 ± 14.0 (range: 20–83) |
Male/female | 69/107 |
Disease | Â |
 Isthmic spondylolisthesis | 14 |
 Degenerative spondylolisthesis | 63 |
 Spinal canal stenosis | 77 |
 Degenerative scoliosis | 13 |
 Vertebral fracture | 9 |
Level of pedicle screw placement | Â |
 L1 | 30 |
 L2 | 48 |
 L3 | 104 |
 L4 | 284 |
 L5 | 320 |
 S1 | 68 |
 Total | 854 |