MATERIAL and METHODS: ETO technique was studied on 3 cadavers and 6 CSes of these cadavers. Endoscopic dissection was visualized with a 0-degree angle endoscope and recorded with fiberoptic cable, light source and camera system and digital video recording system.

RESULTS: Superior orbital fissure (SOF), optic canal (OC), anterior ethmoidal artery (AEA) and posterior ethmoidal artery (PEA) foramens were visualized with periorbital dissection. Anterior wall of CS was reached after drilling the optic strut (OS). When the wall was opened, CS lateral and anteroinferior compartments were visualized. Internal carotid artery (ICA) were visualized from proximal ring to the last 2 cm of paraclival carotid artery. Cranial nerves (CNs) within the CS and the course of the interclinoid ligament were revealed.

CONCLUSION: The transorbital endoscopic method is an alternative approach to other techniques for accessing the lateral and anteroinferior compartments of CS. The advantages, disadvantages and limitations of the technique have been determined. Keywords : Transorbital, Lateral compartment, Anteroinferior compartment, Optic strut, Superior orbital fissure