The bipedicled anterior septal flap: a radioanatomic and cadaveric study.

OBJECTIVES/HYPOTHESIS: Pedicled mucosal flaps are the preferred method of endoscopic skull base reconstruction. Vascularized coverage of the anterior and posterior frontal tables remains a challenge given the lack of large caliber vessels supplying the anterior septum. The objective of this study was to define a novel bipedicled anterior septal (BAS) flap that is hypothesized to be capable of providing reproducible coverage of these difficult areas.

STUDY DESIGN

Radioanatomic and cadaveric study.

METHODS

The flap outline was superimposed over nine midline sagittal computed tomography images. The pedicles are comprised of the septal branch of the superior labial artery and the nasopalatine artery. The flap length subtended the distance from the incisive canal to the sphenoid face at the level of the choanal arch. Radiometric analysis of the flap length to base ratio and anterior/posterior frontal table coverage were calculated. These projected values were confirmed in four cadaveric dissection specimens.

RESULTS

The mean flap length was 39.64 ± 4.26 mm with a mean length:base ratio of 3.29 ± 0.70 and a total surface area of 916.46 ± 262.66 mm(2) . The flap was estimated to provide coverage of 100.31 ± 21.34% of the frontal beak and 50.74 ± 32.54% of the posterior frontal table. In all cadaveric specimens the flap extended beyond the superior aspect of the frontal beak and at least 50% of the posterior table.

CONCLUSIONS

The BAS flap represents a novel septal mucosal flap based on two well-defined arterial inputs. This flap is capable of providing reliable vascularized coverage of the posterior frontal table and the frontal beak following frontal drillout.