Complications, Interventions, and Emergency Utilization After Endoscopic Endonasal Surgery: A National Cohort Analysis

Objective: Endoscopic endonasal approach (EEA) is the predominant technique for pituitary and sellar lesions with favorable outcomes, yet post-operative complication rates have not been delineated using contemporary large-scale data. We utilized a nationwide EHR database to characterize complications following EEA and their temporal trends. Methods: We conducted a retrospective cohort study of patients who underwent EEA (CPT code 62165) between January 2018 and January 2025, identified using Epic Cosmos. Unlisted EEA codes were not included. Post-operative complications, including cerebrospinal fluid (CSF) leak, epistaxis, meningitis, and related surgical interventions, were evaluated at 1-, 2-, 4-, 8-, 16-, and 24-weeks following surgery. Unplanned readmissions within 30 days of discharge and emergency encounters (ED visits or ED-to-inpatient transitions) were also assessed. Cause-specific data were not available, and encounters could not be confirmed as surgery-related. Temporal trends were analyzed using chi-square testing, odds ratios relative to 2018, and logistic regression. Results: A total of 18,008 patients were included. Complications were most common in the early post-operative period ([ Fig. 1 ]). CSF leak occurred in 0.84% at week 1, 2.3% at 1 month, and 3.0% by 16 weeks. Post-operative epistaxis rates at 1 week, 2 weeks, and 1 month were 0.59%, 1.5% and 2.3% respectively and most noted after 1–2 weeks post-op. Meningitis was rare (0.88% overall) with an onset later than other complications: 0.1% at 1 week and 0.5% at 1 month, peaking at 0.8% by 2 months. Emergency encounters of any cause occurred in 3.7% at 1 week and rose steadily to 22.7% at 6 months. Unplanned 30-day readmissions occurred in 6.1% of the cohort. Surgical interventions for epistaxis were uncommon (sphenopalatine artery ligation 0.1%, interventional radiology embolization 0.07%). From 2018 to 2025, complication rates remained stable. In contrast, emergency department utilization increased significantly from 20.6% in 2018 to 25.1% in 2024 ( p < 0.001), with a 4% increase in odds of ED visits per year (OR 1.04, 95% CI 1.03–1.06, p < 0.001). Odds of CSF leak and epistaxis fluctuated in the past 8 years with no consistent trend observed. Conclusion: In this large national cohort, most postoperative complications after EEA surgery occurred within 2 months of surgery, with CSF leak and epistaxis as the common adverse events. CSF leak and epistaxis occurred the earliest and meningitis peaked slightly later. Of note, this study is limited to CPT code 62165, which likely does not capture expanded endoscopic approaches and tumor resections which may have higher risks of complications. While complication rates remained stable across 2018–2025, all-cause emergency department utilization increased steadily over the same period, suggesting evolving patterns of health care use independent of surgical morbidity. These findings highlight the importance of early postoperative monitoring and raise questions about systemic or patient-level factors driving increased ED visits after EEA. Fig. 1 Post-Operative Complications by Time Interval. Publication History Article published online: 27 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany