Impact of Obesity on Cerebrospinal Fluid Leakage After Endoscopic Endonasal Skull Base Surgery: A Systematic Review and Meta-Analysis of 7919 Patients

Background: Obesity is a recognized risk factor for various surgical complications, but its impact on cerebrospinal fluid (CSF) leakage following endoscopic endonasal skull base surgery remains unclear. This systematic review and meta-analysis aimed to investigate the effect of obesity and body mass index (BMI) on intraoperative and postoperative CSF leaks. Methods: A systematic search was performed across PubMed, Embase, Scopus, Web of Science, and Cochrane Library. Eligible studies included randomized controlled trials, prospective and retrospective cohorts, case series, and case-control studies reporting CSF leak rates stratified by BMI (>25, 25-30,>30). Data extraction included study design, sample size, and leak outcomes. Pooled estimates were calculated using random-effects models in R, with heterogeneity assessed by the I 2 statistic. Study quality was appraised using design-appropriate tools. Results: Twenty-seven studies comprising 7,919 patients were included, spanning 2010–2025 across North America, Europe, Asia, and the Middle East. The pooled intraoperative CSF leak rate was 41% (95% CI: 19–62%), while postoperative leak rates were 22% (95% CI: 9–36%) among patients with BMI >25 and 34% (95% CI: 11–58%) among those with BMI>30, with consistently high heterogeneity (I 2 > 97%). Obesity was a significant predictor of postoperative CSF leakage, with obese patients having 73% higher odds of leak compared to non-obese counterparts (OR = 1.73, 95% CI: 1.25–2.39; p = 0.001). Patients with spontaneous CSF leaks demonstrated a high mean BMI of 36.5 kg/m 2 , while those with intraoperative and postoperative leaks had mean BMIs of 31.2 kg/m 2 and 29.8 kg/m 2 , respectively. Each unit increase in BMI was associated with a 3% higher hazard of intraoperative leak (HR = 1.03, 95% CI: 1.00–1.06). Conclusion: Obesity significantly increases the risk of postoperative CSF leakage following endonasal endoscopic skull base surgery. Higher BMI also correlates with intraoperative leak risk, underscoring the importance of preoperative risk stratification and tailored reconstruction strategies in obese patients. Publication History Article published online: 27 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany