Is the sitting position safe in posterior fossa surgery? An analysis of air embolism risk, complications, and surgical outcomes

In posterior fossa surgery, patient positioning (sitting, prone, or park-bench) requires a balance between surgical exposure, blood loss, and hemodynamic effects. Due to inter-center variability and case heterogeneity in the literature, no definitive superiority has been demonstrated. This study compared the effects of different positions on surgical outcomes and complications based on a single-center experience and investigated independent predictors of postoperative complications. A retrospective observational analysis was performed on 336 consecutive patients undergoing posterior fossa surgery between January 2015 and January 2025. Positions were classified as sitting (n = 250, 74.4%), prone (n = 67, 19.9%), and park-bench (n = 19, 5.7%). Surgical position, pathological characteristics, operative time, intraoperative venous air embolism (VAE), postoperative complications, hydrocephalus, mortality, and residual lesion were reviewed. Multivariable logistic regression identified predictors of postoperative complications. Overall mortality was 6.8%, with no significant difference between positions (p = 0.678). Intraoperative clinically evident VAE occurred in 9 patients (2.7% overall), all in the sitting group (3.6% of sitting cases); Transesophageal Echocardiogram (TEE)/Precordial Doppler detected additional subclinical air embolism events (27 patients in total). Postoperative complications were observed in 33.9% of patients, most commonly cerebrospinal fluid fistula (13.7%) and infection (11.3%), without significant differences between positions (p = 0.445). Residual lesions occurred in 16.7% of cases and were less frequent in the sitting position than in the prone position (p < 0.001). Operative time was shorter in the sitting position (p < 0.001). Hydrocephalus was more common in pediatric patients (p < 0.001) and independently predicted postoperative complications (OR=2.06), whereas surgical position did not (p > 0.05). In this large single-center cohort, the sitting position provided advantages in operative time and residual lesion rate, while mortality and complication profiles were similar to other positions. The incidence of clinically evident VAE was low and manageable. The findings support that, under meticulous patient selection and standardized anesthesia and neuromonitorization protocols, the sitting position remains a safe and effective option in posterior fossa surgery.