From postoperative cerebrospinal fluid leak to meningitis: unveiling the risk factors for meningitis after endoscopic skull base surgery

BACKGROUND: Postoperative cerebrospinal fluid (CSF) leak is a significant complication of endoscopic skull base surgery (ESBS) that increases meningitis risk, a serious and potentially life-threatening infection. This study aimed to delineate the risk factors associated with the development of meningitis in patients who experienced postoperative CSF leakage. METHODOLOGY: We reviewed 1,303 ESBS cases for skull base lesion between January 2020 and July 2024 at a single tertiary center. Patient demographics, pathology, intraoperative CSF leak grade, reconstruction techniques, and postoperative CSF leak management strategiesâ€"including the use of nasoseptal flaps, fat grafts, and lumbar drainsâ€"were collected. Clinical and surgical factors were analyzed among patients with postoperative CSF leak to identify associations with the development of meningitis. RESULTS: Postoperative CSF leak was suspected in 49 patients (3.8%). Among them, 36 (2.8%) underwent repair surgery, while 13 (1.0%) were treated conservatively without surgical confirmation. Meningitis occurred in 21 of these patients. Multivariate analysis revealed that intraoperative CSF leak grade, use of fat grafts, lumbar drain insertion, and delayed CSF leak recognition were significantly associated with meningitis development. Patients with grade 3 intraoperative leaks had 3.21-fold increased odds of developing meningitis compared to grade 0. Tumor pathology, nasoseptal flap viability, and hydroxyapatite use were not significantly associated. CONCLUSIONS: The transition from postoperative CSF leak to meningitis is influenced by the severity of intraoperative leakage, reconstructive choices, and the timing of leak detection. Restricting fat grafts and lumbar drains to selected cases and ensuring close postoperative rhinologic surveillance are critical in mitigating infectious complications following ESBS.