Dissection of the Vertebral Artery Fenestration Limb Presenting with Occlusion After Rupture.

Background: Dissection of a vertebral artery (VA) fenestration is extremely rare. We herein present the first case of a patient who presented with the dissection of a VA fenestration limb accompanied by occlusion after rupture, who was treated with internal trapping of the dissected limb and the parent artery proximal to the fenestration.

Case Description: A 55-year-old man presented with sudden headache and altered consciousness. Computed tomography at admission showed subarachnoid hemorrhage. Angiography showed occlusion of the inner limb of the vertebrobasilar junction fenestration, and the occluded ends had a tapered shape, suggesting the occlusion of the dissection of the inner limb after rupture. Angiography immediately before embolization revealed inner limb recanalization with an irregular string sign; thus only the inner limb was embolized. Angiography after embolization showed near-complete suppression of the blood flow in the inner limb; however, a slight antegrade flow through the coil mass was observed in the late phase. The procedure was finished with the expectation of complete occlusion over time with natural heparin reversal. Angiography 8 days after embolization revealed a significant increase in antegrade blood flow through the coil mass within the inner limb. Therefore additional embolization of the parent artery proximal to the fenestration was performed, which achieved complete occlusion.

Conclusions: The embolization length was limited and the antegrade blood flow through the other limb remained during internal trapping for the dissected VA fenestration limb; therefore careful observation of the blood flow to the dissected segment after embolization is necessary.