Comprehension of Two Modalities: Endovascular Coiling and Microsurgical Clipping in Treatment of Intracranial Aneurysms

to weakness of all vessel wall layers. Most cerebral aneurysms probably result from hemodynamicallyinduced degenerative vascular injuries by abnormal hemodynamic shear stresses on the walls of large cerebral arteries, particularly at bifurcation points. It has been reported that 90% of all intracranial aneurysms arise from the anterior circulation (1, 2). Most aneurysms are asymptomatic until they rupture; when aneurysms rupture, they are associated with significant morbidity and mortality. About 15% of patients die before reaching the hospital. The 30-day mortality rate is 45%. Approximately one-half of the survivors sustain irreversible brain damage. Although few cases have been reported to resolve spontaneously in unruptured intracranial aneurysms (UIAs), direct treatment is usually recommended and should be treated in ruptured aneurysms (3-6). The true incidence of intracranial aneurysms is unknown, but is estimated at 0.4-6% of the population (7). The rate of SAH due to rupture of intracranial aneurysms is 6-8 per 100,000 in Western countries and 7-11 per 100,000 in Korea (2, 3, 8-11). Ruptured aneurysms can be treated by microsurgical clipping or endovascular coiling because in so doing, the risks and benefits of further bleeding are prevented (2, 9, 10). In 1990, the Guglielmi detachable coil (GDC; Boston Scientific/Target Therapeutics, Freemont, CA, USA) was introduced, and the coil was approved by the US Food and Drugs Administration (FDA) 5 years later (9). Since 1995, coiling has become widely used in ruptured aneurysms and UIAs, and many studies have reported comparisons between clipping and coiling.