Introduction: Intracranial blister aneurysms are rare lesions that are notoriously more difficult to treat than typical saccular aneurysms. High complication rates associated with surgery have sparked considerable interest in endovascular techniques, though not well studied, to treat blister aneurysms.

Methods: All consecutive intracranial blister aneurysm cases treated using an endovascular approach at our institution between January 2009 and January 2012 were retrospectively analyzed.

Results: Over the study period, 9 patients with blister aneurysms underwent 11 endovascular interventions. In various combinations, stents were used in 8/11, coils were used in 5/11, and Onyx was used in 3/11 procedures. At mean angiographic follow-up of 200 days, 8/9 aneurysms were completely or near-completely occluded by endovascular means alone requiring no further treatment, and 1 aneurysm required surgical bypass and trapping after one failed surgical and two failed endovascular treatments. At mean clinical follow-up of 416 days, mRS scores were improved in 6, stable in 2, and worsened in 1 patient. One complication occurred in 11 procedures (9%), resulting in a permanent residual neurologic deficit. No unintended endovascular parent vessel sacrifice, intra-procedural aneurysmal ruptures, anti-platelet-related complications, post-treatment aneurysmal re-ruptures, or deaths occurred.

Conclusions: This series highlights both the spectrum and limitations of endovascular techniques currently utilized to treat blister aneurysms, including a novel application of stent-assisted Onyx embolization. Long-term follow-up and larger experiences are required to better define the role of endovascular therapy in the management of these difficult lesions.

Patient Care: Highlights the current state-of-the-art of endovascular therapy for blister aneurysms, increases awareness of technical pitfalls and limitations of endovascular techniques in an era where enthusiasm for devices exceeds experience with their use.

Learning Objectives: By the conclusion of this session, participants should understand the unique features of blister aneurysms that make them difficult to treat by standard open surgical or endovascular methods and be aware of the spectrum and limitations of various endovascular techniques available for treating these difficult lesions.

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