３．Endoscopic Approach to the Skull Base and Adjacent Organs

Skull base lesions are difficult to approach due to the delicate structure and the complexity of anatomy.Endoscopic skull base surgery is highly technique dependent and takes great risks.It has undergone rapid advancement in the past two decades moving from simple pituitary surgery to suprasellar lesions and now to extended lesions extending from the anterior skull base to the C2 and laterally to the petrous apex and infratemporal fossa.Key principle of endoscopic endonasal approach(EEA)is choosing a surgical corridor that minimizes the need for neural and vascular manipulation.This review talk would describe and discuss the surgeries in anatomy-based ventral skull base surgical modules along the coronal and sagittal planes.In each section, the anatomy, common lesions, surgical landmarks and skills are provided.On sagittal plane, transsellar, transtuberculum, transplanum, transcribriform, transclival and transodontoid approaches are reviewed.Besides, pterygopalatine fossa, transpterygoid approach, cavernous sinus, foramen lacerum, petrous apex, orbit, and contralateral transmaxillary approach(CTM)would be reviewed on the coronal plane section.We would pay attention to the surgical approaches to the floor of middle cranial fossa.Different approaches would be addressed and the combined approaches would be proposed for a minimally invasive alternative to the lesions of the middle cranial fossa.