Some vertebro-basilar aneurysm may not be treatable at a reasonable risk by direct clipping. A possible alternative is transvascular obliteration, using the means of modern interventional neuroradiology in combination with neurophysiological monitoring. These possibilities and related difficulties are outlined and discussed and the example of two cases with different types of vertebrobasilar aneurysms (top of the basilar artery and basilar trunk aneurysm) which have been treated by balloon embolization.
