Aneurysms of the persistent hypoglossal artery.

The primitive hypoglossal artery is one of four embryonic anastomoses between the carotid and basilar arterial systems. The so-called persistent hypoglossal artery is most likely a complex vessel comprised proximally of a persistent hypoglossal artery and distally of components of the primitive lateral basilar-vertebral anastomotic network. This is the sixth reported case of an aneurysm of the persistent hypoglossal artery, and it is unique in its association with two supratentorial aneuryms, one of which had ruptured. All three aneurysms were treated by a direct surgical approach (two operations). Review of the other published cases demonstrates that these aneurysms arise at the junction of the persistent hypoglossal with the basilar artery. Aneurysms of this vessel require direct surgical treatment, because the parent vessel is functionally the only artery supplying the brain stem and therefore may not be ligated. The aneurysms usually lie in the subarachnoid space, indenting the brain stem, and may be approached through a suboccipital craniectomy.