Characterization of patients of the studied groups.
| Criteria | Group I (n = 192) | Group II (n = 112) | Р Value |
| Age, y, median (Q1; Q3) | 54 (45; 63) | 59 (46; 64) | 0.23 |
| Male/female ratio, n (%) | 134 (69.8)/58 (30.2) | 76 (67.9)/36 (32.1) | 0.42 |
| Number of operated vertebrae, n (%) | |||
| 3 | 117 (60.9) | 73 (65.2) | 0.14 |
| 4 | 61 (31.8) | 31 (27.7) | |
| 5 | 14 (7.3) | 8 (7.1) | |
| Observation period, mo | 27 (25; 32) | 41 (35; 62) | - |
Abbreviations: Q1, quartile 1; Q3, quartile 3.