Midline suboccipital approach to a vertebral artery–posterior inferior cerebellar artery aneurysm from the rostral end of the patient using ORBEYE

BACKGROUND: The midline suboccipital approach with the patient in the prone position is safe and effective for clipping vertebral artery–posterior inferior cerebellar artery (VA–PICA) aneurysms. Using a conventional surgical microscope from the rostral end of the patient for this approach without an extreme head-down position requires the surgeon to overhang the visual axis of the microscope and perform surgical manipulations in an uncomfortable posture. We report performing the midline suboccipital approach from the rostral end with slight head-down position using ORBEYE, a new high-definition (4K) three-dimensional exoscope. CASE DESCRIPTION: A 65-year-old woman was admitted for clipping of a right unruptured VA–PICA aneurysm (maximum diameter, 5mm) located medially and ventral to the hypoglossal canal. After induction of general anesthesia, the patient was placed in the prone position with the head titled slightly downward. A midline suboccipital approach was performed from the rostral end of the patient using ORBEYE. Clipping was safely accomplished in a comfortable posture. No operative complications occurred. Postoperative computed tomography angiography showed complete aneurysmal obstruction. CONCLUSION: Exoscopic surgery using ORBEYE is feasible for a midline suboccipital approach to VA–PICA aneurysms from the rostral end of the patient with the patient in the prone with slight head-down position.