A Paramedian Supracerebellar, Infratentorial Approach for Resection of Midbrain Tumor.

Brainstem tumors represent formidable lesions for neurosurgical intervention. They should be approached with a thorough understanding of the anatomy and clear sense of surgical goals. A 14-year-old previously healthy girl presented with 2 weeks of nausea, headaches, diplopia, and gait instability. Workup revealed a 3.5 x 2.5 x 2.5 cm contrast-enhancing mass within the right midbrain. The patient consented to the surgical procedure. Preoperative imaging demonstrated superior displacement of the deep venous system because of the tumor, as well as inferior displacement of the fourth cranial nerve exit zone and posterior bowing of the entire tectal region. This allowed a safe corridor from a supracerebellar infratentorial approach. The three quarters lateral position was chosen to optimize surgeon ergonomics and allow for gravity to drain blood from the operative field. Near total resection was obtained without any new neurologic deficit. Final pathology was consistent with pilocytic astrocytoma, World Health Organization grade I. The video demonstrates the surgical approach in addition to techniques for brainstem tumor resection (Video 1).