The Nasopharyngo-Septal Butterfly Flap: A Novel Adjunct for Reconstructing Large Skull Base Defects.

Objective: Skull base defects can be challenging to reconstruct. The nasoseptal flap (NSF) remains the first-line option for reconstruction. However, it can be inadequate to cover wide defects or compromised by tumor invasion or prior surgery requiring additional reconstructive options. The goal of the study is to describe a novel flap for clival and craniovertebral junction (CVJ) reconstruction.

Study design: Cadaveric study with an illustrative clinical case.

Setting: Cadaver dissection laboratory and tertiary university hospital.

Methods: Endoscopic endonasal dissection was performed in 15 cadavers. A modification of the inferior incision of the NSF was carried out. The inferior incision was performed at a more cranial location, sparing the mucosa of the posterior septum. Two lateral longitudinal incisions were carried out at the pterygo-sphenoidal junction freeing the nasopharyngeal mucosa. A third incision was performed separating the rostral mucosa from the nasal floor. The resulting flap was rotated postero-superiorly covering the clivus and CVJ.

Results: An inferiorly based butterfly-shaped nasopharyngo-septal flap, consisting of nasopharyngeal and posterior septal mucosa and receiving blood supply from the bilateral ascending pharyngeal arteries, was formulated. The lower wings comprised nasopharyngeal mucosa while the upper wings comprised posterior septal mucosa. The mean surface area of the flap was 12.35 ± 0.21 cm² covering the clivus and CVJ in all cadavers.

Conclusion: The nasopharyngo-septal flap is a novel vascularized flap that is well-suited for reconstructing clival and CVJ defects where the NSF is insufficient and can also be used as a salvage flap in cases where the NSF is unobtainable.