A medical filler delivery assembly includes a micro catheter for delivering filler material such as filamentary material into an aneurysm in a vessel. The assembly also includes a positioning mechanism which includes a support element made of knitted wires, as well as an expansion mechanism for expanding the support element within the vessel. The support element is able to trap the micro catheter in position and in practice such that its distal end is disposed within the aneurysm sac. The knitted wire configuration of the support element provides sufficient holding force to the distal end of the micro catheter and also has an open structure which permits continuation of fluid flow through the vessel. The entire assembly can be removed from the vessel after the delivery of filamentary material, thereby not retaining within the vessel any foreign object such as a stent.
