Diagnosis and treatment of basilar artery perforator aneurysm: A 20-year review with proposed treatment guidelines

Introduction: Aneurysms of the vertebrobasilar system comprise approximately 10%–15% of all intracranial aneurysms and most occur at the bifurcation of the basilar artery. Posterior circulation perforator artery aneurysms are sparsely reported in the literature. The natural history of these rare lesions remains unclear and their diagnosis and management are not well defined. Materials and Methods: All case reports and case series from the past 20 years were analysed, and the results tabulated. Based on broad trends, guidelines were proposed for management. Results: Forty-two cases from 22 case reports and case series were analysed. Most were managed endovascularly, with a complication rate approaching 43%. Observation was another popular treatment option with however a comparable morbidity of 42% only surgery proved to be better overall. Aneurysm size was inversely correlated with complication rate with smaller lesions more prone to rupture and complications. The nature of the perforating artery was also found to be a factor, where direct brain stem perforators from the upper two-third of the basilar artery were found to be difficult to treat both by surgery and endovascular methods, leading to significant failures and complications as compared to the wider circumflex perforating arteries. Conclusion: Scarce published literature that addresses the limited understanding of the natural course of this entity lead to difficulties in proposing broad-based recommendations that are fail proof. Nevertheless, we hope this analysis of 20 years of data helps in shedding light on this difficult disease and its possible treatment options along with risks and outcomes.