[Coil Selection, Handling and Troubleshooting in Detachment Failure].

The first coil should be as thick, long, and large as possible. A retrospective study at the Toranomon Hospital revealed that if the volume of the first coil is 1/3rd or more of the total coil volume, there are less chances of retreatment. Thus, a thick and long first coil contributes to stable long-term anatomical results. The length of the first coil should be approximately 8% of the volume of the aneurysm. After the placement of the first coil, a smaller and shorter coil should be placed sufficiently close to it to complete the procedure. The goal is to achieve prevention of acute re-rupture in ruptured acute aneurysms and life-long prevention of rupture in unruptured asymptomatic aneurysms. If the coil does not detach, check the position of the detachment point, and replace the power supply. In addition, refer to the direction for use of the device for prevention of coil disconnection failure and countermeasures. Although it is not a recommended method, a method of rotating the delivery wire at the detached position to thread the coil and a method of reconstructing the electric circuit with a crocodile clip has been reported.