Magnetic wires: A novel design for neuroendovascular coil retrieval

The present study aimed to evaluate the operation, application and safety of a novel prototype device designed for the retrieval of a migrated coils, an intraprocedural complication of endovascular aneurysm treatment, compared with the widely used Solitaire AB stent retriever. The prototype retrieval device, referred to as magnetic wires, consisted of two microwires that were joined by a small magnetic ring near to the tips. To retrieve a coil, the wires are advanced through the dislodged coil one at a time and then capture the target coil in a chopstick-like manner, as their tips are attracted to the magnet. In vitro tests were performed five times for each retrieval device using a pulsing flow circulator to compare retrieval effectiveness. In vivo efficacy testing was performed in 5 male piglets. The left and right carotid arteries were used to assess the magnetic wires and the Solitaire retriever, respectively. While the two devices successfully retrieved coils in vitro at a rate of 100%, the magnetic wires did so in a shorter time. In vivo, the magnetic wires successfully captured the migrated coils in 3/5 cases (60%), whereas the Solitaire AB stent retriever was successful 4/5 cases (80%). Endothelial injury was observed following magnetic wires retrieval in 1/5 cases (20%) and following use of the Solitaire AB stent retriever in 3/5 cases (60%). These results demonstrate the feasibility and safety of this novel prototype coil retrieval device, which with further development has the potential to be an optimal device for the retrieval of dislodged coils.