Fig. 3

Anterior skull base reconstruction with sphenoidotomy. a An illustration of the sagittal view with sphenoidotomy. b A 0-degree endoscopic view of the anterior skull base with sphenoidotomy and (c) the view after covering with the pedicled nasoseptal flap. d Confirmation of the end point of the coverage under navigation. ASBD: anterior skull base distance, CPFS: coverage at the posterior wall of the frontal sinus, CL: coverage from the limbus, PS: planum sphenoidale