Manufacturing of the occluding filaments. A shows the MF-830 micro forge (Narishige Scientific Instrument Laboratory, Tokyo, Japan) used for the manufacturing of the occluding filaments. The tip of the microloader (Eppendorf AG, Hamburg, Germany) was positioned just above the heatable platinum wire as shown in B. The rounded tip was formed by increasing the temperature of the platinum wire. The heating process was activated and controlled with a foot pedal and could simultaneously be followed through the oculars of the micro forge. The microloader with the black marks has a rounded tip, whereas the microloader below has not been modified (C). The marks were used for the correct positioning of the microloader in the internal carotid artery. The last black mark was placed 22 mm behind the rounded tip and had to be positioned on the level of the carotid bifurcation.