Surgical treatment of basilar aneurysms.

The surgical therapy and results in 17 cases of basilar aneurysms are reported, extending a series of 15 reported previously. Three surgical approaches were used: subtemporal, pterional, and suboccipital. The subtemporal route was satisfactory for most lesions, although the pterional approach has advantages for upper basilar aneurysms projecting either more than 1 cm above the dorsum sellae or directly anteriorly. A low lateral-suboccipital approach is described and recommended for aneurysms of the proximal basilar trunk and vertebrobasilar junction. The recent literature regarding surgical results, classification, pathogenesis, and technical developments for management of these lesions is reviewed. Most of the morbidity resulting from surgery in the midbrain and pontine region is due to direct or indirect injury to perforating vessels. Superiorly directed bifurcation aneurysms carry the highest risk because of their association with perforating vessels. General precepts regarding size, location, patient condition, and timing of operation with respect to aneurysms of the anterior circulation hold true for aneurysms of the posterior circulation.