Comparative Analysis of Cranio-Orbito-Zygomatic and Transorbital Routes to the Superior Orbital Fissure, Orbital Apex, Clinoidal Space, and Suprasellar Cisterns

The superior orbital fissure (SOF), orbital apex (OA), clinoidal space (ClnS) and suprasellar parachiasmatic cisterns (SSPC) represent frequent surgical targets in skull base neurosurgery. Surgical access to these regions remains challenging due to the high density of critical neurovascular structures within multiple cisternal compartments. This study aimed to evaluate a transorbital surgical route to the SOF, OA, ClnS, and SSPC and compare the limits of exposure with those of the conventional trans-sylvian route through a cranio-orbitozygomatic approach (COZA). Methods: Cadaveric dissections were performed to expose the orbital apex, cavernous sinus, sphenoid wing, and suprasellar parachiasmatic cisterns. Trans-sylvian route via COZA was carried out initially, and this was subsequently followed by a transorbital approach directed at the same anatomical areas. Surgical corridors were systematically analyzed, and exposure boundaries were documented and compared. Results: The transorbital route consistently provided access to the SOF, OA, ClnS in addition to the anteromedial cavernous sinus. The extent of exposure achieved via the transorbital route was comparable to that obtained with the COZA for SSPC; however, the transorbital approach appeared to provide a shorter and more direct working corridor. Intradural access to the carotid and proximal sylvian cisterns was achievable; however, chiasmatic and lamina terminalis cisterns were more effectively accessed through the trans-sylvian route via COZA. Conclusion: The transorbital approach offers a direct surgical corridor to selected anterior skull base and parasellar structures without sylvian fissure dissection. While not a substitute for conventional trans-sylvian exposure for all chiasmatic cisterns, the transorbital approach may serve as a complementary or alternative approach for appropriately selected lesions.