Electrothermal Coil Detachment Failure in Flow Diverter-Assisted Coiling of a Small Blister Aneurysm: Technical Considerations and Possible Solutions

Flow diversion stenting combined with coiling offers both immediate protection from rebleeding for ruptured aneurysms and long-term stability for wide-necked or blister aneurysms. It is particularly useful for tiny ruptured aneurysms, alleviating the concern that small coils may prolapse between the struts of conventional stents. We employed this technique in a very small, broad-based ruptured aneurysm of the internal carotid, jailing the coiling microcatheter with a Pipeline Embolization Device. However, coil detachment repeatedly failed, until we withdrew the detachment zone into the microcatheter. We suggest that if the tip of the coiling catheter is adjacent to the stent, contact between the junction zone of the coil and the high metal density of the flow diverter may prevent proper electrothermal coil detachment. Detachment can be undertaken successfully within the microcatheter, though care must be taken thereafter to fully push the detached coil tail into the aneurysm.