Minimally invasive endoscopic-assisted approaches to the posterior fossa

Modern surgical approaches are becoming more minimalistic, associated with the term "minimally invasive." The endoscope provides a more panoramic anatomical view in addition to the ability to access narrow deep corners with decent illumination and clear visualization. Endoscopic assisted microsurgery through a tailored small craniotomy is the foundation of keyhole surgery. The endoscope can be advanced deeper into the field, thus enhancing an exposure and allowing bimanual dissection, ultimately providing smaller craniotomies and tailored key exposures. The term "minimally invasive" became associated with reduction of overall tissue injury, decreased potential complications, reduced recovery times/hospital stay, and overall reduced costs. This minimally invasive concept became successfully applicable to diverse pathologies in the three cranial fossae. The posterior fossa houses the most critical neurovascular structures of the brain in an intricate and complex anatomical organization. In this manuscript, we describe keyhole endoscopic-assisted approaches to different regions of the posterior fossa. Five corridors for these approaches are described: 1) midline supracerebellar-infratentorial to the pineal region; 2) upper cerebellopontine angle (CPA) to the trigeminal region; 3) middle cerebellopontine angle to the vestibulocochlear region and internal auditory meatus; 4) inferior cerebellopontine angle to the jugular foramen region and lower cranial nerves; and 5) midline infracerebellar to posterior foramen magnum and the craniocervical junction. We then present a general review of the published literature and case examples demonstrating the effectiveness of the endoscopic-assisted keyhole concept.