Results and problems on direct embolization of cerebral aneurysms using interlocking detachable coils

The clinical results of direct embolization of cerebral aneurysms using interlocking detachable coils (IDCs) were analysed. In 27 patients who underwent direct embolization of the aneurysm, 19 patients (70%) were treated uneventfully. In the other 8 patients, symptomatic or asymptomatic complications occurred; parent artery occlusion in 3 patients, rupture of the aneurysm in 2 patients, distal embolism in 2 patients, and neurological deterioration due to enlargement of the aneurysm after embolization in 1 patient. In 5 of 8 patients in whom complications occurred, neurological deficits disappeared after additional embolizations or thrombolysis therapies. Permanent deficits were observed in 3 of all patients (11%). These deficits were caused by the parent artery occlusion due to protrusion of the detached coil in wide neck aneurysms. These results suggest that indication of direct embolization of the cerebral aneurysm should be decided according to neck size. Balloon-assisted coil placement in wide-necked aneurysms was useful but unable to prevent protrusion or migration of the coils after balloon withdrawal. Development of a new device, such as a stent for intracranial use, may make it possible.