Postoperative adverse events after spinal surgery: Sex-specific risk profiles and ICU utilization.

Background: Sex differences in surgical outcomes are well-documented, yet data specific to spinal surgery remain conflicting. Research question: We investigated whether postoperative risk truly differs between sexes or if disparities reflect case mix and ICU triage practices. Methods: We analyzed prospectively collected data from 1337 spinal procedures (2023-2025) at a tertiary neurosurgical center. Multivariable logistic and Poisson regression models estimated the independent effect of sex on 30-day outcomes (complications, neurological deficits, rebleeding, ICU admission) and length of stay (LOS), adjusting for age, diagnosis, procedure type, comorbidities (AACCI), and operative time. Results: The cohort included 703 men and 634 women with similar baseline diagnoses. Thirty-day adverse events were equivalent between sexes, including aggregate complications (9.8% men vs 8.8% women), new neurological deficits (2.7% vs 2.1%), and adjusted LOS (mean 8.1 days). Conversely, ICU admission was significantly more frequent in men (8.0% vs 4.1%; p = 0.005). After adjustment, female sex was not associated with complications (aOR 0.95) or LOS, but remained independently associated with reduced ICU admission (aOR 0.42, 95% CI 0.24-0.73), even when accounting for comorbidities and operative time. Conclusions: Despite equivalent complication profiles and hospital stays, women were half as likely as men to be admitted to the ICU. Since this disparity persists after adjusting for clinical complexity and operative burden, ICU utilization in spinal surgery may be driven by provider practice patterns rather than objective physiological risk.