Stenting for a Ruptured Blood Blister-Like Aneurysm of the Basilar Artery: Case Report and Literature Review.

Blood blister-like aneurysms (BBAs) usually occur on the supraclinoid portion of the internal carotid artery. There are a few reports of BBAs in other locations. We provide the case details of a ruptured BBA of the basilar artery (BA) that was treated with stenting, with a good outcome. The patient was a 74-year-old Japanese woman with a World Federation of Neurosurgical Societies (WFNS) grade I subarachnoid hemorrhage. Digital subtraction angiography (DSA) performed on day 14 revealed a BBA with a maximum diameter of 1.5 mm and a wide neck on the posterior wall of the BA's tip. Single stenting was performed on day 20, and an additional stenting was performed on day 26 due to postoperative stent migration. At six months post-operation, DSA revealed that the aneurysm had disappeared, and the patient was recovering well. Ruptured BBAs of the BA are rare and difficult to treat due to high rates of rebleeding and the presence of significant perforating branches. BBAs located on the posterior wall, in particular, are at high risk of ischemic complications. If coil embolization within an aneurysm is difficult, stenting alone may also be an effective treatment.