Microsurgical clipping or endovascular treatment? For unruptured aneurysms, the only specific randomized trial is CURES. In it, treatment failure at one year was 9% with clipping versus 19% with endovascular treatment, with the same overall morbidity and mortality at one year. Clipping involves more invasiveness at the outset, with more transient neurological deficits and longer hospital stays. In return it offers highly durable occlusion: 98.6% recurrence-free at 15 years. E

We have never detected or treated as many unruptured intracranial aneurysms as we do today. Yet subarachnoid hemorrhage is becoming less frequent and less lethal: its incidence fell from 10.2 to 6.1 per 100,000 between 1980 and 2010, and case fatality dropped from 51% to 35%. The paradox has another side: most aneurysms never rupture (the average annual risk is below 1%), but most of those that do rupture are small, the ones we usually call «low risk». Moreover, the decline i