Endoscopic skull base reconstruction: a review and clinical case series of 152 vascularized flaps used for surgical skull base defects in the setting of intraoperative cerebrospinal fluid leak

Endoscopic skull base surgery continues to rapidly evolve, requiring comparable advances in reconstructive techniques. While smaller skull base defects with low intraoperative CSF flow have been successfully managed with a variety of avascular and/or noncellular techniques, larger defects with high CSF flow require more robust repairs often in the form of vascularized flaps, which confer excellent success rates in this setting. Despite these successful outcomes, a paucity of data describing specific patient and operative characteristics and their effects on repair exist. Therefore, a retrospective, consecutive chart review was performed on patients who underwent endoscopic skull base reconstruction with a vascularized flap in the setting of intraoperative CSF leaks. In this series, 151 patients with a mean age of 51 years underwent 152 vascularized flap skull base reconstructions for an array of benign and malignant pathologies. These vascularized flaps included 144 nasoseptal flaps, 6 endoscopic-assisted pericranial flaps, 1 facial artery buccinator flap, and 1 inferior turbinate flap that were used throughout all regions of the skull base. Perioperative (< 3 months) and postoperative (> 3 months) flap complications were assessed and revealed 3 perioperative flap defects (2.0%) defined as a visualized defect within the substrate of the flap and a total of 5 perioperative CSF leaks (3.3%). No patient experienced flap death/complete flap loss in the cohort. Assessed postoperative flap complications included 1 case (0.7%) of mucocele formation, 8 cases (5.3%) of prolonged skull base crusting, and 2 cases (1.3%) of donor-site complication, specifically septal perforation secondary to nasoseptal flap harvest. Among the 152 cases identified, 37 patients received radiation therapy while 114 patients did not undergo radiation therapy as part of the treatment profile. No significant association was found between perioperative complication rates and radiation therapy (p = 0.634). However, a significant association was found between postoperative complication rates and radiation therapy, primarily accounted for by an increased risk for prolonged (> 6 months) skull base crusting (p = 0.025). It is clear that larger skull base defects with high intraoperative CSF flow require thoughtful approach and strong consideration for vascularized repair.