A retrolabyrinthine presigmoid approach was employed successfully in four patients with aneurysms around the vertebral union. This approach allows excellent access to the vertebral union without resection of the sigmoid sinus, with minimum retraction of the cerebellum and brain stem. This approach can be recommended for not only aneurysms of vertebral union and lower basilar trunk, but also VA-PICA aneurysms that are located close to the midline, in high position from the foramen magnum, and far from the clivus.
