Background Blister aneurysms (BAs) of the internal carotid artery (ICA) are associated with high mortality rates and are challenging to treat because of their fragile wall, typically poorly defined neck, and broad communication with the parent artery.

Objective To evaluate the efficacy and outcomes of endovascular compared to open microsurgical treatment for BAs of the ICA.

Methods A literature search of PubMed and Web of Science was performed to identify primary studies from 2000 to 2022 that discussed the clinical outcomes of endovascular or open surgical treatment of BAs of the ICA. Case reports, technical reports, animal studies and non-English studies were excluded. Studies describing modified Rankin Score (mRS) following treatment of BAs of the ICA were extracted for systematic review and meta-analysis.

Results Twenty-six studies describing 519 cases with ruptured BAs of the ICA treated with endovascular or surgical approaches were included. Of the 519 cases, 350 cases were endovascularly managed, while 169 cases were microsurgically managed. Endovascular treatments resulted in better functional outcomes with lower mRS (OR: 4.80; 95% CI = 1.18-19.48; P = 0.03). Pre-operative Fisher grade lower than 3 was associated with better functional outcomes (OR: 6.12; 95% CI = 1.32-28.37; P = 0.02), but age younger than 47 years-old (integer value corresponding to mean age of all patients included in our analysis) was not associated with better functional outcomes (OR: 1.62; 95% CI = 0.44-5.93; P = 0.47).

Conclusion Our results suggested that when endovascular treatment was an option, it was associated with improved outcomes over open microsurgical management. While we examined open versus endovascular interventions for blister aneurysms from a macro scale perspective, future studies should focus on comparing more granular data pertaining to the specific, nuanced variations in techniques within the open and endovascular approach categories. Furthermore, the ways in which specific angioarchitectural makeup, aneurysm location and size, and associated comorbidity factors may make a particular blister aneurysm more suited for one approach over another should be further delineated.

Disclosures N. Brown: None. R. Singh: None. S. Koester: None. J. Gendreau: None.