Balloon-assisted extrasaccular coil embolization technique for the treatment of very small cerebral aneurysms.

Treatment of very small ruptured cerebral aneurysms (< 2 mm) continues to present a challenge. These lesions are difficult to treat both with neurosurgical and endovascular techniques. A neurosurgical approach is still the treatment of choice for these lesions at many centers because of high rupture rates related to endovascular treatment; however, there are clinical circumstances in which the neurosurgical option cannot be offered. In their review of the literature, the authors did not find any series reporting endovascular treatment of these very small aneurysms. In the present study, the authors report their experience with the endovascular treatment of a series of 4 ruptured aneurysms smaller than 2 mm from neck to dome. They describe their technique of using a remodelling balloon to stabilize the tip of the microcatheter in the neck of the aneurysm without entering it at any time, and of inserting the coil from outside the sac to minimize the risk of intraoperative rupture, which is very high when conventional endovascular embolization is performed.