Challenges and changes in the endovascular treatment of very small intracranial aneurysms.

he coiling of very small intracranial aneurysms, that is, those with diameters of 3 mm or less, is associated with T specific pitfalls and risks. The confined space of these aneurysms greatly limits the ability of the surgeon to achieve stable positioning of the microcatheter within the small sac. Furthermore, the size of the aneurysm increases the friction encountered during coil deployment, and this is action thought to increase the risk of intraprocedural rupture (1, 2, 5, 7). Because of these specific pitfalls, the subset of very small aneurysms was excluded from large studies such as the International Subarachnoid Aneurysm Trial and Guglielmi Detachable Coil registry study (4, 8). In the recent Barrow Ruptured Aneurysm Trial, the small size of aneurysms was the most common anatomical reason for crossover from endovascular to surgical treatment (3). Even though very small aneurysms pose specific technical challenges to endovascular surgeons, increasing operator experience as well as the ongoing development and refinement of endovascular devices has led the very small aneurysm size to become less and less of a relative contraindication to endovascular treatment.