Comparison of classification of ROT according to the procedure site
| Brain surgical procedure (n=513) % (95% CI) | Spinal surgical procedure (n=483) % (95% CI) | p Value | |
| ROT | 17.7 (14.5 to 24.2) | 4.0 (2.4 to 6.1) | <10−3 |
| UROT | 14.6 (17.7 to 17.9) | 3.5 (2.1 to 5.6) | <10−3 |
| AE-UROT | 10.8 (8.2 to 13.8) | 3.5 (2.1 to 5.6) | <10−3 |
| Infectious AE-UROT | 2.5 (1.3 to 4.2) | 2.3 (1.2 to 4.1) | 0.83 |
| Haemorrhagic AE-UROT | 3.5 (2.1 to 5.4) | 1.0 (0.3 to 2.4) | 0.01 |
| Other AE-UROT | 5.2 (3.4 to 7.5) | 0.2 (0.0 to 1.1) | <10−3 |
AE-UROT, adverse event-associated UROT; ROT, return to operating theatre; UROT, unplanned return to the operating theatre.