Early Postoperative Adverse Events (≤ 30 Days) in Spinal Oncology: Defining the Incidence, Severity, and Predictors in a Mixed Prospective Cohort Including Intradural and Metastatic Spinal Tumors.
Complication reporting in spinal tumor surgery remains inconsistently defined. We aimed to quantify the incidence, severity, and spectrum of early (≤ 30 days) postoperative adverse events (AEs) in spinal tumor surgery and to identify predictors of overall and serious complications using standardized severity grading. We analyzed prospective data from 156 patients undergoing spinal tumor surgery for mixed primary and metastatic pathologies between 2023 and 2025. Intra- and extradural lesions were included. AEs were classified according to the Clavien-Dindo system, and risk factors were identified using logistic regression. The age-adjusted Charlson comorbidity index (ACCI) was used to assess comorbidity burden. Any postoperative AE occurred in 16.7% of cases, and serious complications (Clavien-Dindo ≥ III) occurred in 7.1%. Surgery-related events predominated (14.7%). Stratified analysis revealed differences between tumor subgroups, with the highest complication rates observed in intramedullary tumors, primarily driven by neurological deficits. The ACCI was the strongest predictor of both overall (p = 0.006) and serious complications (p = 0.001), corresponding to a 20%-39% risk increase per point. Emergency surgery and advanced age were associated with serious complications, while operative duration correlated modestly with overall AEs. Mortality within 30 days was 1.9%. AEs were dominated by neurological and surgery-related complications. Complication profiles differed according to tumor location, reflecting underlying surgical and biological differences. Comorbidity burden and urgency emerged as predictors for AEs in general. These findings underscore the need for structured preoperative risk stratification, timely elective referral, and standardized AE reporting to improve safety and comparability across spinal tumor surgery studies.