The anterolateral triangle enclosed by the foramen rotundum and foramen ovale constitute part of the floor of the MCF.

This study was done with the purpose to assess the feasibility of a transnasal pre-lacrimal approach for accessing the floor of MCF via an anterolateral triangle corridor. Another goal of this study was to determine the extent of maximal exposure while safeguarding neurovascular structures.

A transnasal pre-lacrimal approach was performed in 5 cadaveric specimens with a total of 10 sides. After the identification of foramen rotundum and foramen ovale, the bony ridge between 2 was drilled to expose the MCF. The temporal lobe dura was then elevated laterally, and the distances from foramen ovale to the respective borders of the area of the MCF window were measured using a surgical navigation device.

The MCF was exposed with a 0° scope in all specimens also exposing significant landmarks including the middle meningeal artery, greater superficial petrosal nerve, superior petrous sinus, and arcuate eminence. Preservation of the vidian nerve, greater palatine nerve, lateral nasal wall, and the nasolacrimal duct as possible on all 10 sides.

It is feasible to access the floor of MCF via an endoscopic transnasal pre-lacrimal approach with seemingly low risk.