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  • Effect of Carotid Siphon Anatomy on Aneurysm Occlusion after Flow Diversion for Treatment of Internal Carotid Artery Aneurysms

    Final Number:

    Leonardo Rangel-Castilla MD; Waleed Brinjikji BS; Harry Cloft MD; David F. Kallmes MD

    Study Design:

    Subject Category:

    Meeting: Congress of Neurological Surgeons 2018 Annual Meeting

    Introduction: Flow diversion (FD) is effective for treatment of intracranial internal carotid artery (ICA) aneurysms. We aimed to determine whether carotid siphon (CS) geometry influences the efficacy of FD when employed for ICA aneurysms.

    Methods: Outcomes of a consecutive series of patients with ICA aneurysms treated with FD were retrospectively reviewed. CS anatomy was quantified through measurement of the posterior, anterior, and anterosuperior bend angles in accordance with previously described methodology. The relationship of CS geometry to likelihood of incomplete aneurysm occlusion at one year after treatment was assessed with multivariate logistic regression analysis.

    Results: There were 167 ICA aneurysms in 164 patients treated with FD during the study period. The mean age of our cohort was 55.7 years [Standard Deviation (SD): 12.3] and a majority of patients were female (145/164, 86.8%). Anterior (47.4 degrees vs 8.5, p < 0.001) and anterosuperior bend angles (100.9 vs 76.5, p = 0.002) were significantly greater in aneurysms that required repeat FD after initial treatment. On multivariate logistic regression analysis, increasing patient age (Unit OR: 1.05, 95% CI 1.01-1.08; p = 0.003) and anterior bend angle =-3.5 (OR: 2.47, 95% CI 1.04-5.86; p = 0.046) were associated with increased odds of incomplete aneurysm occlusion at one year after treatment.

    Conclusions: These findings suggest that variations in CS anatomy may influence the efficacy of FD treatment and should be analyzed prior to offering FD for treatment of ICA aneurysms. Further investigation into the hemodynamic effects of CS geometry is warranted.

    Patient Care: Our research will aid in identification in aneurysms at risk of incomplete occlusion after flow diversion, potentially influencing treatment selection and post-operative observation strategies.

    Learning Objectives: By the conclusion of this session, participants should be able to: 1) quantify carotid siphon anatomy through the use of specific angle measurements, and 2) understand how variations in carotid siphon anatomy affects the efficacy of flow diversion for internal carotid artery aneurysms.


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