Treatment of Intracranial Aneurysms: Clipping Versus Coiling

Intracranial aneurysms (IAs) have an estimated incidence of up to 10 % and can lead to serious morbidity and mortality. Because of this, the natural history of IAs has been studied extensively, with rupture rates ranging from 0.5 to 7 %, depending on aneurysm characteristics. The spectrum of presentation of IAs ranges from incidental detection to devastating subarachnoid hemorrhage. Although the gold standard imaging technique is intra-arterial digital subtraction angiography, other modalities such as computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are being increasingly used for screening and treatment planning. Management of these patients depends upon a number of factors including aneurysmal, patient, institutional, and operator factors. The ultimate goal of treating patients with IAs is complete and permanent occlusion of the aneurysm sac in order to eliminate future hemorrhagic risk, while preserving or restoring the patient's neurological function. The most common treatment approaches include microsurgical clipping and endovascular coiling, and multiple studies have compared these two techniques. To date, three large prospective, randomized studies have been done: a study from Finland, International Subarachnoid Aneurysm Trial (ISAT), and the Barrow Ruptured Aneurysm Trial (BRAT). Despite differences in methodology, the results were similar: in patients undergoing coiling, although rates of rebleeding and retreatment are higher, the overall rate of poor outcomes at 12 months was significantly lower. As minimally invasive procedures and devices continue to be refined, endovascular strategies are likely to increase in popularity. However, as long-term outcome studies become available, it is increasingly apparent that they are complementary treatment strategies, with patient selection of critical importance.