Does a Full-Fluid Diet Reduce the Risk of Post-Operative CSF Leak After Expanded Endonasal Approach in Skull Base Surgery?

Background: Low fluid intake is consistently linked to higher constipation risk and consequent straining. Studies show an inverse, dose-responsive, non-linear relation between dietary moisture and constipation, with the greatest risk reduction when moving from the lowest to higher intake. After expanded endoscopic approach (EEA) in skull base surgery, postoperative straining is theoretically thought to raise intracranial pressure and stress a dural repair. Therefore, we examined whether a short-course full-fluid diet reduces postoperative CSF leak risk. Our study aims to find out if a 7 days full-fluid diet post EEA skull base surgery is associated with decreased risk of CSF leak. Methodology: A retrospective cohort study was conducted at a tertiary center in Lebanon. Patients who underwent EEA skull base surgery were included, and their postoperative management, including diet, was determined by long-standing surgeon preference as part of routine care. All patients received stool softeners. A group of patients were receiving a full-fluid diet course for 7 days, and another group received a regular diet. We compared postoperative CSF-leak rates between groups after excluding patients with major comorbidities, trauma, or malignancy. Results: Postoperative CSF leak occurred in 1/106 (0.94%) in the full-fluid group and 0/87 (0%) in the regular-diet group. The difference was not significant. No hyponatremia reported in either groups. These findings suggest that diet texture did not reduce CSF leak risk in this cohort, though the study is underpowered to detect small differences. Conclusion: A short-course full-fluid diet was not associated with lower postoperative CSF leak rates compared with a regular diet. These findings do not support diet texture as a CSF leak-prevention strategy. Although larger, prospective studies are warranted to detect small effects and guide postoperative dietary practice. Publication History Article published online: 27 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany