Postoperative Epistaxis After Endoscopic Endonasal Skull Base Surgery: Incidence, Timing, and Clinical Implications

OBJECTIVE: To determine the incidence, timing, bleeding sources, and associated factors of clinically significant postoperative epistaxis after endoscopic endonasal skull base surgery in a large single-center cohort. STUDY DESIGN: Retrospective cohort with a frequency-matched case-control analysis. SETTING: Single tertiary center. SUBJECTS AND METHODS: Among 1070 adults who underwent endoscopic endonasal skull base surgery (2015-2025), patients who developed postoperative epistaxis requiring medical evaluation or surgical intervention (n = 13) were compared with 52 frequency-matched controls without bleeding. Bleeding timing, endoscopic bleeding sources, management, and exploratory univariable associations were evaluated. RESULTS: The incidence of clinically significant postoperative epistaxis was 1.2%. Bleeding occurred between postoperative Days 0 and 28 (mean ± SD, 13.1 ± 7.6 days; median, 14 days), and 76.9% occurred during Days 8 to 23. Identified bleeding sources included posterior septal branches of the sphenopalatine system (23%), flap donor site or inferior septal mucosal edge (15%), diffuse mucosal oozing (23%), and cerebrospinal fluid-mixed bleeding (15%). In exploratory univariable analyses, hypertension (odds ratio, 4.90; 95% CI, 1.35-17.80) and postoperative systemic steroid use (odds ratio, 3.60; 95% CI, 1.02-12.73) were associated with bleeding. Most patients (92.3%) required endoscopic surgical re-exploration for definitive hemostasis. CONCLUSION: Clinically significant postoperative epistaxis after endoscopic endonasal skull base surgery most often occurred during the second to third postoperative week and commonly originated from posterior septal branches or donor-site mucosa. These findings highlight the importance of careful postoperative monitoring and a low threshold for early endoscopic evaluation when clinically significant bleeding occurs.