| 摘要 |
The present invention relates to a guidewire which comprises an elongated core, the distal end portion of which has been made more flexible by cutting notches 2-25 % of the diameter into the elongated core. The notches may be a continuous helical notch or discrete, axially or circumferentially spaced notches in the distal end portion. In an alternative embodiment, the distal end portion of the elongated core may be ground to a constant diameter which is smaller than that of the proximal end of the elongated core. In an additional embodiment, the distal end portion may be ground to a diameter which tapers from a larger diameter adjacent to the proximal end to a smaller diameter at the distal end of the distal end portion. In both such embodiments, the distal end portion is also notched to further increase flexibility. In an alternative embodiment, a polymeric sleeve may be bonded to the distal end portion of the elongated core to encase the notched distal end portion. In an additional embodiment, a helically wound spring is disposed at its proximal end within a continuous helical notch in the distal end portion of the elongated core. The spring is then bonded to the elongated core using a suitable means. The distal end of the spring extends distally of the distal end portion of the elongated core. A safety wire is connected at one end to the distal end portion of the elongated core and at the other end to the rounded tip. The distal end portion of the elongated core may also be either ground to a smaller diameter or to a taper relative to the diameter of the proximal end. In an alternative embodiment, the elongated core is notched in an intermediate portion and is either tapered or is made of a smaller diameter in the distal end portion. A helically wound spring is disposed at its proximal end within a continuous helical notch in the intermediate portion. The distal end of the spring extends distally of the distal end portion of the elongated core. |
