Risk factors for perioperative morbidity in spine surgeries of different complexities: a multivariate analysis of 1,009 consecutive patients

The present study confirms several modifiable and non-modifiable risk factors for perioperative and early postoperative morbidities in spine surgery, among which surgical factors (such as complexity, revision surgery, and instrumentation, including the pelvis) play a crucial role. A classification of surgical complexity is proposed and validated.