Contemporary Treatment of Intracranial Blood Blister Aneurysms - A Systematic Review.

[INTRODUCTION] Blood blister aneurysms (BBAs) are rare aneurysms affecting non-branched points of intracerebral arteries. Due to their small size and fragility, BBAs are prone to rupture, and can be challenging to diagnose and treat. Several treatment options have been suggested yet there is no consensus regarding the best modality to reduce morbidity and mortality.

[MATERIALS AND METHODS] A systematic review of the literature was conducted searching for articles discussing the treatment of BBAs. Inclusion criteria included: articles published between January 2010 and August 2020, English language, with each paper including at least 15 patients. Studies included required detailed reporting of patient demographics, treatment, and patient outcomes (including complications, recurrence, neurologic functional status, and mortality).

[RESULTS AND DISCUSSION] A total of 25 studies with 883 patients were included. Most were female (n = 594, 67.3%) and aneurysms were overwhelmingly located in the supraclinoid internal carotid artery (99%). Aneurysms were variable in size and mostly presented with subarachnoid haemorrhage. Endovascular treatment (n = 518, 58.7%) was more common than microsurgery (n = 365, 41.1%) while only 2 patients were managed conservatively. Complications were more common in patients treated microsurgically. Microsurgical procedures had an unfavorable outcome (mRS 4-6, GOS 1-3) rate of 27.8% (n = 100/360) while that of endovascular procedures was 14.7% (n = 70/477). Endovascular procedures had a lower mortality rate than microsurgical interventions (8.4% vs 11%).

[CONCLUSION] This review demonstrates that endovascular treatment of blood blister aneurysm has reduced morbidity and mortality when compared with microsurgical treatment. Small sample sizes and substantial study heterogeneity makes strong conclusions difficult.