Management strategies for intraprocedural coil migration during endovascular treatment of intracranial aneurysms

Migration of a coil during endovascular treatment of intracranial aneurysm occurs in 2-6% of cases. The consequences of coil migration vary significantly from minor flow alterations of the parent artery which are asymptomatic to thromboembolic occlusion of major intracranial vessels resulting in large territory infarcts. We performed a comprehensive literature review and identified 37 reported cases of migrated coil retrieval consisting of 10 case reports and six case series. Most of the aneurysms presented with rupture (65%) and were located in the anterior circulation (70%). The endovascular treatment approaches were coil embolization alone (57%), stent-assisted coiling (26%) and balloon remodeling (17%). Endovascular retrieval was performed with microwires, the Alligator Retrieval device, Merci devices, snares and stentrievers. There was a single report of microsurgical extraction following failed endovascular removal and three cases of coil fracture in which the coil fragments were secured to the vessel walls with stents.