Patient procedural characteristics between severe and minor Clavien grades.
| Patient Procedural Characteristics | Clavien Grade | Total | P Value | |
| Minor | Severe | |||
| Anterior approach | 9.08% | 13.27% | 12.4% | 0.036 |
| Posterior approach | 72.42% | 65.82% | 66.67% | 0.156 |
| Combined approach | 11.37% | 14.32% | 13.59% | 0.09 |
| Anterior decompression | 3.33% | 5.62% | 3.91% | <0.001 |
| Posterior decompression | 39.43% | 35.59% | 35.82% | 0.694 |
| Iliac fixation | 20.17% | 19.68% | 15.65% | <0.001 |
| Osteotomy | 33.96% | 30.84% | 27.11% | <0.001 |
| 3-Column osteotomy | 10.05% | 7.29% | 6.68% | 0.051 |
| Interbody device placement | 28.00% | 33.74% | 31.22% | <0.001 |
| Anterior fusion (0.49 [1.31]) | ||||
| 1 Level | 10.05% | 7.12% | 8.50% | <0.001 |
| 2–3 Levels | 4.78% | 6.24% | 7.10% | 0.005 |
| 4–7 Levels | 3.74% | 2.64% | 3.40% | 0.001 |
| 8+ levels | 0.69% | 0.35% | 0.60% | 0.026 |
| Posterior fusion (3.87 [4.74]) | ||||
| 1 Level | 40.68% | 45.43% | 32.70% | <0.001 |
| 2–6 Levels | 12.68% | 14.59% | 15.50% | 0.048 |
| 7–12 Levels | 21.28% | 15.38% | 16.80% | 0.001 |
| 13+ Levels | 14.35% | 11.60% | 10.20% | <0.001 |
| Anterior lumbar interbody fusion | 8.87% | 16.61% | 13.87% | <0.001 |
| Posterior lumbar interbody fusion | 79.49% | 71.53% | 70.81% | 0.200 |
| Operative time, min, mean (SD) | 387.1 (148.6) | 346.6 (159.3) | 336.1 (153.9) | 0.169 |
Note: Boldface indicates statistically significant findings at P < 0.05 across complication levels.