Transsphenoidal approach with nasoseptal flap pedicle transposition: modified rescue flap technique.

INTRODUCTION The adoption of vascular pedicled flaps to reconstruct skull base defects following endoscopic endonasal skull base surgery is a significant milestone in the development of endoscopic endonasal approaches (EEAs). In 2006, Hadad and Bassagaisteguy introduced the pedicled nasoseptal flap (NSF). The NSF decreased initial postoperative cerebrospinal fluid (CSF) leak rates from >20% to <5% overall, with a 94% success rate following reconstruction of high-flow intraoperative CSF leaks. It is a robust, relatively straightforward to harvest flap that provides a large surface area, and can be rotated to cover a wide variety of skull base defects. Currently, the NSF is widely used and is considered the workhorse for skull base reconstruction following EEAs. In addition, it heals quickly, can be modified to better address complex or multiple defects, and can be reused in revision cases. In a similar fashion to endonasal skull base surgery, the NSF has evolved over time. One product of this evolution was the development of the nasoseptal rescue flap (NSRF). This technique protects the pedicle of the NSF while obviating the need to fully dissect its paddle. A NSRF is indicated in cases where a CSF leak is possible, but not likely. The specific technique for raising the NSRF has been previously described. The salient aspects of the NSRF are the use of the posterior-superior limb of the NSF incision, followed by the inferior reflection and retraction of the pedicle. If the NSF is required for reconstruction, the harvest can be completed following the tumor resection. Otherwise, the mucosa containing the pedicle is repositioned at its original site. Based on our experience, we found the NSRF efficacious in preserving septal mucosa and in eliminating the time and donor site morbidity associated with raising the entire flap. However, we noticed that too often the pedicle required constant retraction and still impeded dissection and exposure of the floor of the sphenoid sinus and lower aspect of the clival recess. Furthermore, the continuous and significant retraction often results in tearing of the pedicle or avulsion of the vessels. Therefore, we modified the technique to include inferior incisions that allow for a greater degree of freedom of the pedicle. This modification successfully improved the ability to transpose the pedicle out of harm’s way.