Additional Rescue Stent Placement for Stabilization of a Prolapsed Coil during Stent-assisted Coil Embolization of a Wide-Neck Intracranial Aneurysm.

We report a case of a 55-year-old man carrying two unruptured internal carotid artery (ICA) wide-neck aneurysms. In the same session, the smaller aneurysm was treated by coils using the remodeling technique and the large aneurysm was treated by stent-assisted coil embolization. During the stent-assisted procedure for the large aneurysm, the microcatheter tip moved from the aneurysm into the parent artery causing a prolapse of some coil loops into the vessel lumen. The distal part of the coil was tangled within the stent's struts, therefore, in order to introduce the entire coil, an attempt was made to withdraw the prolapsed loops of the coil within the microcatheter and concomitantly repositioning the microcatheter into the residual aneurysm neck through the stent struts. However this maneuver was unsuccessful. An attempt to retrieve gently the coil also failed and the coil prematurely detached. For maintaining the patency of the arterial lumen and to reduce the embolic risk, a second stent was used to pin the free coil loops. The rescue stent was positioned within the coil loops and its deployment allowed a circumferential expansion of some loops around the stent perimeter while other loops were flattened against the wall of the artery. The parent artery remained patent at one-year follow-up angiographic study. No clinical complications were observed.