Transthird ventricular approach for a high basilar bifurcation aneurysm. Report of three cases.

Three cases of ruptured aneurysm at the basilar bifurcation accompanied by megadolichobasilar anomaly were successfully treated using a transthird ventricular approach. A translamina terminalis approach was used to enter the third ventricle. In two cases, the floor of the third ventricle had been partly destroyed by aneurysm rupture, and a small split in the third ventricular floor was necessary to gain a wide operative field. In the third case, an intact floor was opened along the midline. Clipping was accomplished in all three cases after preserving the perforating arteries. Postoperatively, no complications from splitting the floor were observed. Key surgical points and the prospective view of the transthird ventricular approach are discussed.