CSF Rhinorrhea After Endoscopic Trans-Sphenoidal Surgery (ETSS): Repair Technique, Management Protocol, and Lessons Learned

Introduction: Cerebrospinal fluid (CSF) rhinorrhea is one of the most common and clinically significant complications of endoscopic trans-sphenoidal surgery (ETSS). Although ETSS has matured into a safe and effective approach for pituitary adenomas, the challenge of preventing and managing CSF leaks continues to impact recovery, infection risk, and long-term outcomes. This study describes a single-surgeon experience with a standardized “plug-in” repair protocol, selective lumbar drainage, and key lessons learned over long-term follow-up. Methods: Between 2020 and 2025, 650 consecutive patients undergoing ETSS for pituitary adenomas were retrospectively reviewed. Intraoperative arachnoid breaches were classified as: • Grade 1 - minor, low-flow leaks • Grade 2 - moderate leaks • Grade 3 - large or high-flow leaks Repair involved autologous fat and tensor fascia lata (TFL) grafts, reinforced with fibrin glue. The plug-in technique was systematically applied in Grade 2–3 leaks, with selective use of vascularized nasoseptal flap (NSF) augmentation and lumbar drainage (LD). Data on leak grade, flow rate, technical feasibility, and postoperative outcomes were analyzed. Results: Intraoperative arachnoid breach occurred in 80 patients (12.3%): 40 Grade 1, 20 Grade 2, and 20 Grade 3. Fifteen patients had high-flow leaks. Plug-in repair achieved successful intraoperative sealing in 36/39 patients (92.3%); failures ( n = 3) were related to inaccessible or poorly visualized sites. Elective LD was used in all Grade 3 and selected Grade 2 cases. Postoperative CSF rhinorrhea occurred in 4 patients (0.6% overall; 5% of leak subgroup): • Two Grade 3 defects, due to incomplete sealing or missed site. • Two Grade 1 leaks, which resolved with conservative LD management. NSF augmentation did not independently reduce leak rates when plug-in repair was adequate. No cases required permanent CSF diversion. Discussion: This series highlights the efficacy of the plug-in technique as a reliable and reproducible method for intraoperative leak closure during ETSS. Autologous fat and TFL, compactly inserted into the defect, provide mechanical stability and watertight sealing. Key determinants of success include precise localization of the breach, adequacy of plug placement, and careful avoidance of overpacking, which can compromise chiasmal or vascular structures. Lumbar drainage is not universally required but remains valuable for large or high-flow leaks, supporting graft adherence during the critical healing phase. The low postoperative leak rate (