de Sousa described his experience with 123 operated patients of basilar bifurcation aneurysms from January 1977 till December 1995. In these 123 consecutive surgeries the results were 85% good outcome, 8.1% morbidity, and 6.5% mortality. In the first years of this series the pterional or subtemporal approaches were used, depending on the level of the basilar bifurcation, the exact origin of the sac, its projection and size. From 1987 on all patients were operated by a modified pterional approach described initially by Sano as temporopolar approach ¹⁾.