The extended nasoseptal flap for coverage of large cranial base defects

Background: The nasoseptal flap (NSF) is commonly used to repair skull base defects via a transnasal endoscopic approach. The original description of the technique includes 2 parallel incisions that follow the sagittal plane of the septum. We describe a novel modification to the traditional NSF that allows coverage along the posterior wall of the frontal sinus. Methods: In addition to the 2 sagittal incisions, a third incision is made between these coursing along the maxillary crest from the posterior edge to the midportion of the flap. This provides an extension that can be rotated further anteriorly. We report 4 adult patients with skull base defects too large and anterior to cover with a traditional NSF, on whom we successfully reconstructed with the extended flap. We also performed the technique on six cadaver heads (11 flaps) to provide average measurements of the extension. Results: Our patients were successfully repaired with maintained flap survival. We were able to achieve an average of 1.9 cm, or 26.8%, of additional length on the cadaveric study. Conclusion: The relaxing incision described here creates a flap that allows for reconstruction of a larger range of skull base defects.