[Endoscopic Endonasal Surgery for Tumors in the Posterior Fossa and Cerebellopontine Angle]

Endoscopic endonasal surgery (EES) has rapidly evolved as a minimally invasive option for ventral posterior fossa lesions, offering a direct midline corridor while avoiding soft-tissue dissection, cerebellar or temporal lobe retraction, and the extensive petrosectomy required in traditional open approaches. However, the indications, anatomical concepts, and technical nuances for safely applying EES to intradural posterior fossa tumors have not yet been standardized. This article presents a practical, stepwise overview of EES for posterior fossa intradural tumors arising around the clivus and ventral brainstem. Based on a three-level clival classification (high, middle, and low clivus defined by Dorello's canal and glossopharyngeal meatus), we outlined the rational selection and execution of transsphenoidal transclival, transpharyngeal transclival, and combined approaches with pituitary transposition. Detailed descriptions of the nasal and skull base exposure, management of high-flow venous and CSF bleeding, and multilayer reconstruction using fascia, rigid buttress, fat graft, and a robust rhinopharyngeal flap. By sharing a reproducible high-resolution strategy grounded in anatomical principles and reconstructive techniques, we aimed to facilitate the safe expansion of EES indications for complex posterior fossa tumors.