Qualitative variables by group.
| Variable | Deformity, n (%) | Degenerative Disease, n (%) | P Value |
| Gender | |||
| Men | 4 (44.4) | 4 (22.2) | |
| Women | 5 (55.6) | 14 (77.8) | 0.375 |
| Revision surgery | |||
| Yes | 2 (22.2) | 7 (38.9) | |
| No | 7 (77.8) | 11 (61.1) | 0.667 |
| Area | |||
| Thoracic spine | 1 (11.1) | 1 (5.6) | |
| Lumbar spine | 3 (33.3) | 16 (88.9) | |
| Thoracolumbar spine | 5 (55.6) | 1 (5.6) | 0.003 |
| No. of segments fused | |||
| 2 | 1 (11.1) | 8 (44.4) | |
| 3 | 3 (33.3) | 8 (44.4) | |
| 4 | 3 (33.3) | 2 (11.1) | |
| 5 | 2 (22.2) | 0 (0.0) | 0.057 |
| Antibiotic prophylaxis | |||
| Cefazolin | 4 (44.4) | 13 (72.2) | |
| Vancomycin | 1 (11.1) | 0 (0.0) | |
| Cefazolin + aminoglycoside | 3 (33.3) | 4 (22.2) | |
| Cefazolin + gentamicin + rifampicin | 0 (0.0) | 1 (5.6) | |
| Unspecified | 1 (11.1) | 0 (0.0) | 0.207 |
| Obesity (by body mass index [kg/m2]) | |||
| <30 | 5 (55.6) | 7 (43.8) | |
| 30–35 | 3 (33.3) | 8 (50.0) | |
| >35 | 1 (11.1) | 1 (6.2) | 0.840 |
| Smoking | |||
| Yes | 1 (11.1) | 0 (0.0) | |
| No | 8 (88.9) | 18 (100) | 0.333 |
| No malnutrition | 8 (100) | 18 (100) | 0.050 |
| American Society of Anesthesiologists class | |||
| II | 1 (11.1) | 9 (50.0) | |
| III | 8 (88.9) | 9 (50.0) | 0.091 |
| History of infection | |||
| Yes | 1 (11.1) | 0 (0.0) | |
| No | 8 (88.9) | 18 (100) | 0.333 |
| Early infection | 8 (100) | 18 (100) | 0.050 |
| Deep infection level | 9 (100) | 18 (100) | 0.083 |
| Bacteria | |||
| Gram-positive | 3 (33.3) | 7 (38.9) | |
| Gram-negative | 4 (44.4) | 3 (16.7) | |
| Polymicrobial | 2 (22.2) | 8 (44.4) | 0.268 |
| Measurement of C-reactive protein level | |||
| Performed | 0 (0.0) | 1 (5.9) | |
| Not performed | 7 (100) | 16 (94.1) | 1.000 |
| Sonication | |||
| Performed | 1 (12.5) | 1 (5.6) | |
| Not performed | 7 (87.5) | 17 (94.4) | 0.529 |
| Pathogen concordance | |||
| Yes | 4 (44.4) | 9 (50.0) | |
| No | 5 (55.6) | 9 (50.0) | 1.000 |
| No. of irrigations | |||
| 1 | 3 (33.3) | 10 (55.6) | |
| 2 | 4 (44.4) | 7 (38.9) | |
| 3 | 1 (11.1) | 0 (0.0) | |
| 4 | 0 (0.0) | 1 (5.6) | |
| 6 | 1 (11.1) | 0 (0.0) | 0.303 |
| Plastic surgery | |||
| Yes | 3 (33.3) | 2 (11.1) | |
| No | 6 (66.7) | 16 (88.9) | 0.295 |
| Vacuum-assisted closure therapy | |||
| Yes | 4 (44.4) | 2 (11.1) | |
| No | 5 (55.6) | 16 (88.9) | 0.136 |