2026 Poster Presentations
P238: THE NASOSEPTAL "MIRROR" FLAP FOR EXPANDED ENDOSCOPIC SKULL BASE RECONSTRUCTION
Neal R Godse, MD1; Olivia R O'Brien, BS2; Andrew S Venteicher, MD, PhD3; 1Department of Otolaryngology-Head and Neck Surgery, University of Minnesota Medical School, Minneapolis; 2University of Minnesota Medical School, Minneapolis; 3Department of Neurosurgery, University of Minnesota Medical School, Minneapolis
Since its introduction in 2006, the nasoseptal flap has become a cornerstone of skull base reconstruction, reducing postoperative cerebrospinal fluid (CSF) leak rates from approximately 20% to 3–5%. Despite this success, the traditional flap can be limited in cases involving large or complex defects, particularly when the arterial supply is compromised due to tumor invasion or prior surgical manipulation. In this study, we describe two cases of patients with extensive skull base tumors. In both cases, the anticipated resection defect spanned the middle and anterior cranial fossae with significant lateral extension to the infratemporal fossa with the potential for high flow CSF leak. Moreover, the tumors involved the ipsilateral sphenopalatine artery, eliminating the potential for an ipsilateral nasoseptal flap for reconstruction. Given this, a novel modification of the nasoseptal flap was designed which allowed simultaneous harvest of bilateral septal mucosa, pedicled on the contralateral (non-tumor) sphenopalatine artery. This was achieved by modifying the typical posterior, inferior choanal cut (ipsilateral to the pedicle along the posterior edge of the septum) to cross the spheno-vomeral junction along the nasopharyngeal roof superiorly and the palato-vomeral junction inferiorly (Figure 1). This allowed the ipsilateral (tumor side) septal mucosa to remain attached to the contralateral flap (non-tumor) via the confluent mucosal surface along the posterior free edge of the septum. The final flap had two distinct, but connected, mucosal paddles which were mirror images of each other. In both cases, the extra surface area obtained using this method allowed for complete coverage of the skull base defect. In the second case, the flap was used to successfully reconstruct a high flow CSF leak at the middle cranial fossa through the infratemporal fossa. In both cases, both portions of the flap (ipsilateral and contralateral mucosal paddles) demonstrated brisk fluorescence with intraoperative indocyanine green fluorescent endoscopy. At one month post-operatively, both flaps had healed completely. This modified mirror flap may be useful in cases where the typical vascular pedicle of the nasoseptal flap is not present on one side of the nasal cavity (due to revision surgery, pathology, or the need for extensive transpterygoid exposure). In addition, the orientation of the paddles of the flap allows for extensive coronal or sagittal plane coverage.
Figure 1. Schematic representation of mirror flap. Drawing demonstrates a left pedicled flap. A) View from the left nasal cavity. B) View from the right nasal cavity. QC - quadrangular cartilage; NF - nasal floor; V - vomer; PP - perpendicular plate; SO - sphenoid ostium; VP - vascular pedicle
