Skull Base Reconstruction Following Endoscopic Endonasal Approaches: A Systematic Literature Review of Postoperative Cerebrospinal Fluid Leak Rates Across Closure Techniques

Objectives: To synthesize postoperative cerebrospinal fluid (CSF) leak rates across all major skull base reconstruction techniques following endoscopic endonasal approaches (EEA) within a single unified framework. Design: PRISMA-guided systematic review with descriptive quantitative synthesis; publication bias assessed by funnel plot with Egger's regression test. Setting: Systematic literature search of PubMed, Research Rabbit, and Google Scholar for original studies reporting postoperative CSF leak outcomes following EEA tumor resection. Participants: Eighty-nine studies published between 2004 and 2026, comprising 16,402 patients undergoing EEA for tumor resection. Main Outcome Measures: Pooled postoperative CSF leak rate (n/N, %) overall and stratified across seven prespecified closure categories: no closure or minimal reconstruction; fat-based closure; nasoseptal flap (NSF)-based closure; free mucosal graft closure; watertight dural closure (WTDC); gasket seal and rigid buttress; and miscellaneous techniques. Results: Overall pooled postoperative CSF leak rate was 3.11% (510/16,402). Category-level rates were: no closure or minimal reconstruction 1.00% (22/2,196); fat-based closure 4.22% (123/2,916); NSF-based closure 6.29% (196/3,116); free mucosal graft 2.14% (16/748); WTDC 1.85% (24/1,295); gasket seal and rigid buttress 2.12% (104/4,898); and miscellaneous techniques 2.66% (72/2,710). Individual studies could contribute data to more than one category where applicable. Conclusions: No closure or minimal reconstruction and WTDC produced the lowest pooled leak rates; NSF-based closure produced the highest, reflecting preferential deployment in inherently higher-risk reconstructive scenarios rather than intrinsic inferiority. These findings provide a contemporary technique-spanning benchmark and highlight the need for prospective, intraoperative-leak-grade–stratified comparative studies to guide evidence-based closure decisions in EEA surgery.