Stepwise Algorithm for Skull Base Reconstruction in Endoscopic Endonasal Surgery: From the Simple to the Complex

Abstract

INTRODUCTION: The most frequent complication of endoscopic endonasal surgery (EES) is postoperative cerebrospinal fluid (CSF) leak. This study was designed to develop a step-wise algorithm for EES reconstruction across the spectrum of skull base defects: from free mucosal graft for uncomplicated pituitary adenomas to free flaps in complex cases with recurrent leaks. METHODS: All patients with skull base pathologies who underwent EES between January 2017 and December 2018 were included and retrospectively analyzed. Tumor location, reconstruction method and postoperative CSF leak were reviewed and a step-wise algorithm based on size and location of defect was developed. RESULTS: Location of skull base defects was categorized as follows: anterior fossa, suprasellar, sellar and posterior fossa. For all nonsellar sites, we performed a multilayer (collagen matrix + /-fascia lata + /-fat graft + vascularized flap) reconstruction. The nasoseptal flap (NSF) was the first choice for vascularized reconstruction when available. For all sellar lesions we employed a free mucosal graft unless a high-flow CSF leak was present, in which case a single-layer reconstruction with NSF was performed. When the NSF was not available, alternative local (lateral nasal wall flap) and regional (extracranial pericranial flap) pedicled flaps were successful choices. When patients failed multiple attempts at repair, regional or microvascular free flaps were options. Lumbar spinal drainage was employed for large anterior and posterior fossa defects and during secondary repair of postoperative CSF leaks. Of 347 patients, 4.6% had a postoperative CSF leak. Of 158 patients with an intraoperative leak (45.5%), 10.1% developed a postoperative CSF leak: 7.8% for sellar/suprasellar defects and 13% for anterior/posterior fossa defects. CONCLUSION: This algorithm provides a standardized, stepwise approach to the reconstruction of all skull base defects after EES based on location.