Surgical Anatomy and Technique

Copyright © 2009 by the Congress of Neurological Surgeons Extended endoscopic endonasal approaches are becoming increasingly applied in the management of various intracranial pathol ogies along the midline cranial base. On one end of the complexity spectrum lie lesions such as pituitary adenomas and encephaloceles of the cribriform plate, which can be more easily approached through the endonasal corridor (5, 13, 16, 39, 43). On the other end, increasingly challenging lesions such as chordomas, meningiomas, esthesioneuroblastomas, and suprasellar craniopharyngiomas are more demanding to the endoscopic approaches, as they often require extensive drilling of the cranial base and can surround or invade neurovascular structures (12, 14, 15, 17, 22, 25–28, 30, 31, 33, 42, 47). However, these same challenges face the surgeon using open transcranial approaches to similar lesions. Despite the availability of both endonasal and transcranial corridors, little work has been performed to directly compare their applicability and limitations in reaching cranial base targets (6–8). ABBREVIATIONS: BA, basilar artery; CN, cranial nerve; ICA, internal carotid artery; OCR, opticocarotid recess; ON, optic nerve; OZ, orbitozygomatic; PS, planum sphenoidale; 3D, 3-dimensional; TS, tuberculum sellae; 2D, 2-dimensional; VA, vertebral artery THREE-DIMENSIONAL AND 2-DIMENSIONAL ENDOSCOPIC EXPOSURE OF MIDLINE CRANIAL BASE TARGETS USING EXPANDED ENDONASAL AND TRANSCRANIAL APPROACHES