Right Cerebellomedullary Cistern Epidermoid: Microsurgical Resection Via Far Lateral Transcondylar Approach: 2-Dimensional Operative Video

Intracranial epidermoid cysts are rare, benign lesions accounting for 1% of intracranial tumors.¹ They may arise from misplaced squamous epithelium during neural tube closure, and are found in the paramedian position, cerebellopontine angle, or parasellar region with other locations considered rare.^2-4 The far lateral approach and its extensions enables access and visualization of ventral and ventrolateral lesions at the craniocervical junction without retraction.^5-15 A 32-year-old female patient presented with gait instability, visual disturbances, and severe headaches. Magnetic resonance imaging (MRI) demonstrated a solid, non-contrast enhancing T1 hypointense and T2 hyperintense lesion in the right cerebellomedullary cistern with mass effect on cerebellum and brainstem, consistent with radiologic findings of epidermoid cysts. The patient underwent far lateral suboccipital craniotomy (performed by KIA) with partial posterior medial condylectomy and C-1 hemilaminectomy while prone, which enabled unobstructed ventral view. A 4-hand (i.e., 2-surgeon) microsurgical technique in tumor resection enabled dynamic, gentle tissue retraction and safe tumor resection (Video 1). Apart from transient swallowing problems that resolved 2 weeks postoperatively, the patient's postoperative course was uneventful. Follow-up MRI revealed gross total removal. This video demonstrates the steps, anatomy, and technical nuances for vascular and neural preservation during removal of epidermoid cysts in the cerebellomedullary cistern. To the best of our knowledge, this is the first operative video showing the resection of a pure cerebellomedullary cistern epidermoid cyst. The utility of fat graft dural closure enhancement decreased the risk of cerebrospinal fluid leak. The patient provided consent. Institutional review board approval was not required for individual cases and thus was not sought.