Study of the Nasoseptal Flap for Endoscopic Anterior Cranial Base Reconstruction

Objectives/Hypothesis: Measure the dimensions of the nasoseptal (NS) flap and the anterior skull base (ASB) defect. Verify whether the flap is sufficient to cover the defect. Study the anatomy of the septal artery (SA). Study Design: Anatomical and radiological study. Methods: After endoscopic craniofacial resection, sufficiency of the flap to cover the ASB defect was assessed. The SA was dissected. The number of branches in the pedicle and the distance between the artery and the sphenoid ostium were noted. Radiologic study analyzing CT scans of 30 patients for comparison among measurements of the NS flap and the ASB defect was performed. Results: In all cases the flap was sufficient to cover the ASB. Two branches of the SA were found in the pedicle in 71.4%. The distance between the SA and the sphenoid ostium was 9.3 mm. The reconstruction area of the flap (17.12 cm(2)) was larger than the defect area (8.64 cm(2)) (P < .001). The difference between the superior length of the flap and the anterior-posterior distance of the defect was <= 5 mm in 26.7%. Comparison between the anterior flap width and the anterior defect width revealed that in 33% the difference was <= 5 mm. Conclusions: The dimensions of NS flap are sufficient to cover completely the ASB defect. The anterior edge of the defect presents increased risk for failure in coverage. Additional width adding the nasal floor mucosa to the flap is important to decrease the risk of gap in the anterior orbit-orbit defect. It is more common to find two branches of the SA in the pedicle.