Management of intraprocedural spontaneous stent migration into target aneurysm during stent-assisted coiling procedure.

The stent-assisted coiling technique has expanded the applicability of endovascular treatment for wide-neck intracranial aneurysms. However, the stability of the deployed stent has been questioned. We present this case to demonstrate intraprocedural migration of the deployed stent and subsequent management. A 59-year-old female patient presented with dizziness and fatigue. Imaging, including CT and MR angiography, revealed a 7×6.5 mm wide-neck basilar tip aneurysm. Stent-assisted coiling was attempted. After deployment of the stent, the distal portion of the stent migrated into the aneurysm sac, and then stabilized. Since attempted coiling without an assistance device was unsuccessful, the balloon-assisted coiling technique was applied. Near-total obliteration of the basilar tip aneurysm was accomplished. The stability of a deployed stent should be confirmed to exclude the possibility of intraprocedural stent migration. If stent migration into the target aneurysm occurs, the balloon-assisted coiling technique through the deployed stent is a feasible and valuable tool for successful coil embolization.