Use of Detachable Coils Without the Need of a Double Marker Microcatheter: Technical Note

When using detachable coils for cerebral aneurysm embolization, it is necessary to place a microcatheter with radiopaque markers at 2 sites (tip and 3 cm proximal from the tip) in most cases. Detachable coils that can be positioned independently from the proximal marker may facilitate new applications utilizing their characteristics. Herein, we report 2 cases that were treated with new applications. Detachable coils that function to electrically detect the moment they come out of the microcatheter were used. In one patient with a large aneurysm with an irregular shape, coil embolization was applied by advancing the catheter more than 3 cm from the aneurysm neck to the caudally protruded compartment near the proximal end of the neck, which was difficult to reach with the coil. In the other patient with cerebral arteriovenous malformation (AVM), microcatheters for AVM without a proximal marker were used for coil embolization before Onyx injection: Coil embolization was applied through one microcatheter to a site more proximal than the tip of the other microcatheter, followed by Onyx injection through the distal catheter, by which the nidus was continuously penetrated from the initiation of injection, obtaining an effect similar to that of the plug and push technique. Through the use of detachable coils, which are not dependent on the visibility of the proximal marker, the limitation of catheter positioning is reduced and the applicable types of catheter increase, which may facilitate to enable its use for new clinical indications.