A guidewire useful for feeding a medical catheter through a body duct network to a distant target site within the body has a flexible distal portion. The distal portion facilitates threading the guidewire in a tortuous path through acute bends at branch junctions in the duct network. The guidewire end is able to feed into very delicate vessels such as ventricles of the brain and the spinal canal without puncturing the walls or damaging organs.
The novel guidewire includes beads displaced longitudinally at the distal end of a core wire. The beads are separated by a gap distance. The core wire can flex at points within the gaps between beads which allows the dial end of the guidewire to bend at branch junctions and to conform to the curvature in the vessel duct. The beads can be fixed to the core wire or they can move freely along the distal portion. Also, beads freely sliding along the core wire can be compressed against each other to control the degrees of stiffness and curvature of the distal portion by manipulating the proximal end of the guidewire outside the body during deployment of the guidewire. An insertion tube is provided for initially feeding the flexible guidewire end into the body duct.