Ruptured Basilar Artery Perforator Aneurysm Definitely Diagnosed with Intraoperative Microsurgical Findings: Case Report and Literature Review

Abstract

Initial three-dimensional computed tomography and cerebral angiography fail to identify any aneurysm in 20% of cases of subarachnoid hemorrhage. Basilar artery (BA) perforator aneurysms are rare, and approximately 30%-60% were not identified by initial angiography. A 71-year-old male was transferred with a sudden onset of headache and loss of consciousness. Computed tomography demonstrated subarachnoid hemorrhage, but no ruptured aneurysm was detected. Repeat preoperative cerebral angiography indicated a bifurcation aneurysm of the circumflex branch of the superior cerebellar artery perforator, but microsurgical observation identified the BA perforator aneurysm. If the location of the BA perforator aneurysm cannot be clearly identified, as in this case, repeat angiography should be considered, and the treatment strategy should be decided based on a detailed consideration of the site of the aneurysm.

Keywords: basilar artery perforator aneurysm; repeat angiography; subarachnoid hemorrhage; surgical intraoperative findings.

Fig. 1

a: Head CT scan demonstrated diffuse SAH in the perimesencephalic cistern (Fisher group 3). b: DSA showing no cerebral aneurysm on day 1. c: MPR angiogram on day 5 showed a tiny aneurysm (arrow) between the BA and the left SCA. d: MPR angiogram on day 14 showed an aneurysm (arrow) with a neck on the SCA, which was slightly different from the finding on day 5. e: Selective angiogram (MIP axial view) using a microcatheter on day 21 revealed the aneurysm (arrow) between the SCA (small arrow) and the circumflex branch of the SCA perforator (arrowhead). f: The aneurysm (arrow) was below the posterior clinoid process (red arrowhead).

Fig. 2

a, b: Pre-clipping surgical views showing that the neck of the aneurysm was located on the basilar artery perforator. c, d: Post-clipping surgical views showing that only the rupture point was clipped.