Early Rebleeding of Small Anterior Communicating Artery Aneurysm with Presumed Extrusion of Coil Loop to Outside the Aneurysmal Wall during Endovascular Treatment: A Report of Two Cases

Although endovascular treatment has been proved to be as effective as surgical clipping in the prevention of rebleeding of ruptured aneurysm, early rebleeding after coil embolization has seldom been reported. We experienced early rehemorrhage in two patients of ruptured small anterior communicating artery aneurysms of complete treatment with coil-embolization initially. In both cases what interested us was not early rebleeding itself but how the presumed extrusion of the first part of coil loop beyond aneurysmal wall developed. However, there was no evidence of intraprocedural rupture and moreover complete occlusion with only one or two coils was obtained. Our two patients underwent successful second treatment. We discovered the presumed extruded first part of the coil loop initially was located inside the enlarged aneurysmal sac in retreatment stage. In case of coil embolization of ruptured small anterior communicating aneurysm, the phenomenon we experienced with no evidence of intraprocedural rupture in spite of obvious extrusion of coil loop beyond the aneurysmal wall can be a sign of necessity for early follow-up study including plain radiography to track the change in the presumed extruded coil loop.