Aneurysms of the basilar artery trunk.

Ten cases of basilar artery trunk aneurysms are reported; nine were operated on by a middle subtemporal approach and one by a pterional transsylvian technique. The middle subtemporal approach facilitated clipping of aneurysms located as deep as 25 mm below the posterior clinoid process as seen on the lateral views of the angiogram, such that the junction of the vertebral arteries was visible in most cases. The authors emphasize the usefulness of direct retraction of the trigeminal nerve, the pons, and the aneurysm itself; occasionally, drilling off the pyrimidal edge is also valuable. Surgical results were satisfactory in seven cases and poor in one; two patients died.