Minimally Invasive Transnasal Approach to the Anteromedial Temporal Fossa and Lateral Sphenoid Using a Novel Landmark between Periorbita and Periosteum of the Pterygopalatine Fossa: A Cadaveric Study

The anteromedial temporal region and the lateral wall of the sphenoid can be the site of an array of pathology including trigeminal schwannoma, encephalocele, cholesterol granuloma of the petrous apex, malignancy, infection, and sellar pathology extending to the lateral cavernous sinus. Approaches to this region are technically challenging and the existing approach requires sacrifice of all of the turbinates including the nasolacrimal duct, which can cause postoperative complications. We describe a novel anatomical landmark between the periorbita and the periosteum of the pterygopalatine fossa (which is located at the inferolateral periorbital periosteal line [ILPPL]). The posterior one-third of the incision line lies between the foramen rotundum and the superior orbital fissure, which is proximal to the maxillary strut. A 1.5-cm incision can divide the orbital and pterygoid contents and lead us to the posterior inferolateral orbital region, anteromedial temporal region, lateral wall of the sphenoid sinus, and lateral wall of the cavernous sinus. A combined multiangled approach to the ILPPL will enable us to preserve all of the turbinates and the septum, and the nasolacrimal duct, allowing for the preservation of the physiological function and pedicled flaps, such as the middle turbinate, inferior turbinate, and septal membrane flap. The ILPPL is a simple, effective, and novel landmark for the minimally invasive approach to the anteromedial temporal fossa.