Introduction: Asymptomatic aneurysm management changed in large part due to the findings printed in such publications as ISUIA I and II. The present and projected future trends in aneurysm management will have significant implications for patients and how we educate future cerebrovascular specialists.

Methods: Previous surveys in this field focus almost exclusively on postoperative outcomes while the focus of this study is the insights of experts into the different treatment methods and the decision-making processes. We present an up to date international survey with a focus on rupture risk factors, management trends and decisions for endovascular vs. open techniques. We then determine the implications of these trends to the practice of neurosurgeons. We summarize our findings from a panel of 231 experts across 5 continents from both academic and private practices, stratifying these experts according to geographic criteria and level of expertise.

Results: 1) When to treat according to size and location: 4 mm: 47.6% for AcoA vs. 50.4% MCA choose to always treat these aneurysms by either clipping (27.2% AcoA vs. 40.1% MCA) or coiling (22.4% AcoA vs. 10.3% MCA). 10 mm: Equally divided on the choice of endovascular treatment vs. clipping when it came to AcoA. Europe showed a clear bias in favor of choosing coiling as a method of treatment. 16 mm: There was a clear change in choosing clipping over coiling, even with the AcoA group. 2) How to treat using risk factors: The presence of co morbidities and young age were the most important risk factors in choosing endovascular and open treatment techniques respectively. Further details and data will be provided.

Conclusions: There is a significant discrepancy between the recommendations of the accepted papers and real world practice that is illustrated in graphs. When this is stratified geographically a significant difference in practice around the world is detected.

Patient Care: 1. Improve the awareness of the geographical difference in practice among Neurosurgical experts 2. Educate future cerebrovascular neurosurgeon 3. Develop an understanding of up to date experts opinions in managing asymptomatic aneurysms around the world 4. Decision making in which mode of treatment to choose (Open vs. endovascular) 5. Help guide us for a future larger scale study to develop guidelines in treating asymptomatic incidental aneurysms

Learning Objectives: Find a common ground of approach for all well trained and highly experienced neurosurgeons in the decision-making paradigm and the implications of these trends to the practice of neurosurgeons.

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