Patent ID: 8414634

Claim:
An elongate medical device comprising: a flexible elongate body possessing a distal end portion; an electromagnet disposed at the distal end portion of the elongate body; the electromagnet possessing a proximal end, a distal end and a tapering outer diameter portion at which the outer diameter of the electromagnet decreases towards the distal end of the electromagnet; the electromagnet being energizable to generate a magnetic field at the distal end portion of the elongate body; a helical embolic coil made of ferromagnetic material mounted on the distal end portion of the elongate body, the helical embolic coil possessing a tapering proximal end portion having a tapering shape at which the inner diameter of the proximal end portion of the embolic coil decreases towards a distal end of the embolic coil, the proximal end portion of the helical embolic coil possessing the tapering shape before the helical embolic coil is mounted on the distal end portion of the elongate body, a proximal-most end of the helical embolic coil being open to permit the distal end portion of the elongate body to be inserted into the tapering proximal end portion of the helical embolic coil; the tapering proximal end portion of the helical embolic coil being mounted on the distal end portion of the elongate body so that the distal end portion of the elongate body is positioned inside the tapering proximal end portion of the helical coil, the tapering proximal end portion of the helical embolic coil and the tapering outer diameter portion of the electromagnet axially overlapping one another, and the tapering outer diameter portion of the electromagnet magnetically attracting the tapering proximal end portion of the helical embolic coil to secure the helical embolic coil to the distal end portion of the flexible elongate body in one energization status of the electromagnet, and releasing magnetic attraction of the tapering proximal end portion of the helical embolic coil by changing the energization status of the electromagnet to be different than the one energization status.