In the literature, 30% of VB system aneurysms are reported to be fusiform and not amenable to neck clipping. The authors reported 14 cases of VB fusiform aneurysms that were not possible to exclude from the circulation with a surgical clip or ligature. In our series, intracranial proximal occlusion of the vertebral artery was performed in three cases, coating or wrapping in four, and only a shunting operation was done in three cases. In the remaining four cases, conservative management was continued without any surgical intervention.
The natural courses of the conservatively managed patients were relatively benign, as were the postoperative courses of the surgically treated cases. One patient died of a progressive mass effect of a giant aneurysm, which was not eliminated by a shunting operation. In another case of a giant VB fusiform aneurysm, angiographical obliteration of the aneurysm was obtained by proximal clipping of the ipsilateral intracranial vertebral artery.
Recent reports have described the occurrence of dissecting aneurysms in the VB system. Some of these aneurysms may be angiographically indistinguishable from fusiform aneurysms, unless they show a typical“double lumen”sign. In our series, only one patient was surgically verified to be a dissecting aneurysm, in which a subadventitial hemorrhage was observed in the vertebral artery just proximal to the PICA origin. Some of the other cases were suspected of dissecting aneurysm on angiography, although they were not surgically verified.
The authors' experience indicated that proximal occlusion of the vertebral artery is the procedure of choice in the treatment of ruptured or mass-effect-producing fusiform or dissecting aneurysms in the VB system.
