Microsurgical clip obliteration of intracranial aneurysms was the primary modality of treatment before 1991, when Guglielmi first described occlusion of an aneurysm by an endovascular approach with electrolytically detachable coils.139 With advancements in both microsurgical and endovascular approaches, algorithms to determine the proper patient population and aneurysmal characteristics for each treatment are continually undergoing refinement. The only multicenter randomized trial comparing microsurgical and endovascular repair, ISAT, randomized 2143 of 9559 screened patients with aSAH across 42 neurosurgical centers