A Case of Bilateral Vertebral Artery Dissecting Aneurysm Treated With Multimodality Therapy Under Superficial Temporal Artery Assistance–Posterior Cerebral Artery Bypass

A ruptured bilateral vertebral artery dissecting aneurysm (BVDA) is a challenging vascular disorder. Trapping surgery with bypass assistance could be a potential treatment; however, there is a risk of ischemic complications. Recently, endovascular treatment has been reported, but its long-term outcomes remain uncertain. The patient was a 57-year-old male who presented with subarachnoid hemorrhage. Digital subtraction angiography showed a dilated dominant left vertebral artery (VA) and a narrowed right VA, suggesting a BVDA. First, we performed a right superficial temporal artery-superior cerebellar artery (STA-SCA) insurance bypass. We then performed proximal clipping of the left vertebral VA. The pulsation of the STA-SCA bypass disappeared on day 6. Three-dimensional computed tomography angiography (3DCTA) showed the emergence of a fusiform aneurysm and proximal stenosis of the contralateral VA. On day 31, we performed a superficial temporal artery-posterior cerebral artery (STA-PCA) insurance bypass. Stent-assisted coil embolization was planned for two days after the STA-PCA bypass. However, preoperative angiography showed progression of right proximal VA stenosis, and stenting appeared impossible. There was no change in somatosensory evoked potential (SEP), and angiography showed sufficient retrograde blood flow to the posterior circulation during the right VA balloon occlusion test (BOT). Therefore, internal trapping of the right VA was performed. Postoperative angiography showed perfect patency of the left STA-PCA bypass and retrograde blood flow to the posterior circulation. There was no additional neurological deficit after endovascular treatment. Multimodality therapy could be a potential treatment for bilateral VA dissection.