Abstract
In treatments for vertebral artery (VA) lesions involving the origin of the posterior inferior cerebellar artery (PICA), known as PICA‒involved lesions, various methods have been attempted to preserve the PICA. We report a case of subarachnoid hemorrhage from an atypical lesion of the VA around the origin of the PICA, which was treated by internal trapping with stent placement. A 62‒year‒old woman with occipital headache and vomiting was admitted to our hospital. A computed tomography (CT) scan revealed a subarachnoid hemorrhage primarily in the posterior fossa. Cerebral angiography showed no apparent bleeding source such as an aneurysm or dissecting lesion, but extravasation of the contrast medium was seen around the right VA with no connection to the subarachnoid space. The extravasation disappeared on left VA angiography with interruption of the right VA blood flow by a balloon catheter placed just proximal to the origin of the PICA. We attempted treatment for this right VA lesion similar to that for a PICA‒involved lesion. The next day, we placed an external ventricular drain and performed endovascular therapy with internal trapping by coil embolization just proximal to the origin of the PICA after placing a stent in the range of the PICA and distal VA across the VA union via the left VA. Post‒treatment left VA angiography showed that the extravasation had disappeared with preservation of the blood flow of the right PICA. The patient was discharged home with a modified Rankin Scale score of 0. We believe that a tiny aneurysm and dissecting lesion had occulted and a pseudoaneurysm had formed through a fistula to the exterior of the artery. We achieved complete cure and control of the bleeding source at the VA with preservation of the PICA by internal trapping and stent placement in the range of the PICA and distal VA via the contralateral VA. We consider this method to be superior to direct surgery with regard to both surgical invasiveness and technical difficulty, although there is some risk of thrombotic complications during the perioperative period.
