Two-Operator Endoscopic Resection of Left Cerebellopontine Angle Epidermoid

Intracranial epidermoid cysts are developmental central nervous system abnormalities that arise from erroneous ectodermal inclusion during neural tube closure. Epidermoids are relatively common, representing 1% of all intracranial masses, and are particularly predominant in the cerebellopontine angle (CPA), where they are the third most prevalent diagnosis after schwannomas and meningiomas. Although small, asymptomatic, or incidental lesions may be safely observed, in the presence of symptomatic mass effect, epidermoid cysts typically require surgical resection. As shown in Video 1, we demonstrate the operating room setup and endoscopic resection of a left CPA epidermoid cyst through a retrosigmoid craniotomy. By use of a 2-surgeon 4-hands technique, the mass was dissected from the surrounding neurovascular structures, and a gross total removal was achieved with no postoperative neurologic deficits. Our video highlights the critical nuances pertinent to the fully endoscopic resection technique, with special attention to the relative restrictions of a small working corridor parallel to the tentorium and the petrous bone.