Surgical techniques: Endoscopic transseptal approach (Video 1)
After lateralization of bilateral turbinates, the first incision was
made anterior to the nasal septal body to avoid bleeding. The mucosal
flap was elevated from the subperichondrial and continuing subperiosteal
planes, followed by dissection superiorly to the perpendicular plate of
the ethmoid bone, posteriorly to the sphenoid rostrum, laterally to the
sphenoid sinus ostium, and inferiorly to the nasal floor. Another
incision on the other side was made posterior to the nasal septal body
to avoid perforation, followed by the same dissection. Partial removal
of the perpendicular plate was performed, and we applied a Cottle nasal
speculum between the septal flaps to establish a surgical corridor and
to prevent unexpected injury to the septal mucosa and olfactory
neuroepithelium (Fig. 1A and 1B). Then we performed sphenoidotomy by
removing the rostrum. After creating a sufficient space for four-hand
surgery, neurosurgeons removed the tumor until the arachnoid membrane
descended (Fig. 1C and 1D). Finally, we repositioned the septal flaps
and restore bilateral middle turbinates to the neutral position to
prevent sinusitis. Bilateral incision wounds were left unsutured to
facilitate drainage of exudate.