Endoscopic approaches to the petrous apex

Surgical approaches to the petrous apex include transtemporal, middle cranial fossa, and transsphenoidal approaches. Lateral approaches risk brain injury, facial paralysis, and loss of hearing and vestibular function. Recent advances in minimally invasive surgery with the use of intraoperative navigational systems allow transnasal endoscopic access to petrous apex lesions with minimal morbidity. Removing bone medial to the internal carotid artery at the level of the clival recess can drain cholesterol granulomas of the petrous apex. Potential advantages include avoidance of a craniotomy, faster recovery, minimal postoperative symptoms, shorter hospitalization, and improved maintenance of a drainage pathway. This article describes the authors' technique for endoscopic surgery of the petrous apex (medial approach), and highlights the important anatomic relationships and potential problems of an endoscopic approach.