Although endovascular coiling has been shown to be a safe and effective treatment, some of these same patients require repeat treatment for recurrence of an aneurysm [30 31]. Published series regarding mid and long-term clinical outcome and follow up angiographic findings confirm that recanalization may occur in up to 33% of treated patients, which also tends to increase in the aneurysms with wider necks and larger sizes [2 30 32 33]. In the case of coiled aneurysms, large aneurysms are more likely to recur than smaller ones and ruptured aneurysms are more likely to recur than unruptured ones [11 30].