Abstract
Objective Reconstruction of large clival defects after an endoscopic endonasal procedure is
challenging. The objective is to analyze the morphology, indications, and limitations
of the extended nasoseptal flap, which adds the nasal floor and inferior meatus mucosa,
compared with the standard nasoseptal flap, for clival reconstruction.
Design Twenty-seven sides of formalin-fixed anatomical specimens and 13 computed tomography
(CT) scans were used. Under 0-degree endoscopic visualization, a standard flap on
one side and an extended flap on the other side were performed, as well as exposure
of the sella, cavernous sinus, and clival dura mater. Coverage of both flaps was assessed,
and they were incised and extracted for measurements.
Results The extended flap has two parts: septal and inferior meatal. The extended flaps are
20 mm longer and add 774 mm2 of mucosal area. They cover a clival defect from tuberculum to foramen magnum in
66.6% cases and from below the sella in 91.6%. They cover both parasellar and paraclival
segments of the internal carotid arteries. The lateral inferior limits are the medial
aspect of the hypoglossal canals and Eustachian tubes. CT scans can predict the need
or limitation of an extended nasoseptal flap.
Conclusions The nasal floor and inferior meatus mucosa adds a significant area for reconstruction
of the clivus. A defect laterally beyond the hypoglossal canals is not likely covered
with this variation of the flap. Preoperative CT scans are useful to guide the reconstruction
techniques.
Keywords
cerebrospinal fluid leak - clival reconstruction - endoscopic endonasal - nasoseptal
flap - skull base
