BackgroundEndoscopic repair of cerebrospinal fluid (CSF) fistulas is a fundamental practice in anterior skull base surgery due to high success rates and low morbidity profile. However, spontaneous CSF (sCSF) leaks have the highest recurrence rate compared to other etiologies. The most effective management is undetermined due to variations in graft materials and limited evidence.ObjectiveWe present the largest study of a standardized endoscopic repair technique for sCSF leaks.MethodsSingle-institution retrospective review of patients who underwent endoscopic sCSF leak repair between October 2011 and January 2018. All patients underwent repair using a temporary lumbar drain, intrathecal fluorescein, and multilayer reconstruction using bilayered fascia lata autograft and vascularized nasoseptal flap.ResultsTwenty patients (100% female, mean age: 53.2 years) with 25 separate sCSF leak sites were included. Obesity was present in 15 of 20 patients (mean body mass index [BMI] = 35.3). No patients had previous sinus surgery. Locations of skull base defects included: cribriform plate (44%), ethmoid (32%), lateral sphenoid (12%), and planum sphenoidale (12%). The mean follow-up was 22.8 months and 92% of the leak sites (23/25) were successfully repaired primarily. There were no neurological complications or cases of meningitis. Two patients (mean BMI = 52) with persistent postoperative CSF leaks and elevated intracranial pressure were successfully managed with ventriculoperitoneal shunt placement. BMI was associated with likelihood of repair failure (P = .003).ConclusionsAt our institution, endoscopic repair of sCSF leaks using a composite autograft of fascia and a nasoseptal flap demonstrates high success rates. Elevated BMI was a statistically significant risk factor for revision.