Background: Unruptured intracranial aneurysms (UIAs) are increasingly identified and are an important health-care burden; in the past they were commonly treated by surgical clipping, but nowadays endovascular coil embolization is increasingly employed as an alternative.
Methods: The Unruptured Aneurysms Italian Study (UAIS) is a multicentric cooperative prospective study aimed to delineate the "State of the Art" of UIAs treatment in Italy. 51 Italian Neurosurgical and Neuroradiological Units, representatives of all 20 Italian regions are involved in the Study.
Results: UAIS started on June 2003 and ended on July 2007. 1138 patients were collected by that date, but 181 were ruled-out due to severe violation of the protocol; 957 had complete data and could be statistically evaluated.
Conclusions: UAIS demonstrates that the treatment of UAs, as performed in Italy as a Nation, is effective in improving long-term outcome vs. natural history, particularly in aneurysms larger than 7 mm.