Vertebral Artery Junction Aneurysm: Brain Stem Compression due to a Giant Dolichoectatic and Partially Thrombosed Aneurysm Involving the Intradural Segments of Both Vertebral Arteries and the Proximal Trunk of the Basilar Artery; Asymptomatic Thrombosis of the Vertebral Artery Junction After Ventricle Shunting; Endovascular Disconnection of the Vertebrobasilar Junction Using Coil Occlusion of Both V4 Segments and Flow Diverter Stent Deployment from Both Posterior Inferior Cerebellar Arteries to the Afferent V4 Segments; Long-Term Follow-Up Showing Aneurysm Shrinkage and Good Clinical Outcome

Abstract

A 61-year-old female patient was admitted to another hospital with severe dizziness accompanied by nausea and dysbasia. An MRI examination revealed a large, partially thrombosed dolichoectatic basilar artery (BA) trunk and distal vertebral arteries (VA) aneurysm with no signs of active bleeding. This was exerting significant mass effect on the brain stem. Selective vertebral and three-dimensional rotational angiography revealed the morphology of the large aneurysm. The changes originated approximately 0.5 cm proximal to both the anterior inferior cerebellar arteries (AICA) and seemed to end 0.5 cm distal to the origins of the posterior inferior cerebellar arteries (PICA). When bilateral internal carotid injections were performed, neither the proximal part of the basilar artery nor the aneurysm filled. After multiple multidisciplinary discussions, it was felt that the best strategy would be to implant a ventricular catheter prior the endovascular treatment. However, shortly after the surgical procedure and the break in the aspirin regime that procedure necessitated, the patient reported that both the dizziness and the nausea had severely worsened. Cross-sectional imaging revealed slight aneurysmal growth as well as notable changes in the blood flow of both the proximal basilar artery and the target aneurysm. Both AICAs and the proximal one-third of the basilar artery were filling through the anterior circulation. The VAs were now mainly supplying the PICAs. We theorized that interrupting the mono-antiplatelet therapy and placing a ventricular catheter had induced completely unintended yet favorable hemodynamic changes for the aneurysm. Staged endovascular treatment with distal parent vessel occlusion for both VAs followed by disconnecting the vertebrobasilar junction via flow diverter stents into both PICAs was considered to be a potential curative solution. The management of this large partially thrombosed VA junction aneurysm is the main topic of this chapter.