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Variable stiffness guidewire

  • US 7,867,176 B2
  • Filed: 12/27/2005
  • Issued: 01/11/2011
  • Est. Priority Date: 12/27/2005
  • Status: Expired due to Fees
First Claim
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1. A variable stiffness guidewire for navigating through body vessels, comprising:

  • a tube having a proximal portion substantially comprised of a first material and a distal portion substantially comprised of a second material, wherein said second material is different from and more flexible at human body temperature than said first material;

    an elongated corewire received by the tube and including a distal end, a proximal end, and a protruding portion extending beyond the distal portion of the tube;

    a unitary coiled spring surrounding at least said protruding portion of said corewire, said spring having a distal end associated with said distal end of said corewire and a proximal end associated with said distal portion of said tube, wherein said corewire is axially movable with respect to said tube to adjust the total length of the spring and thus the stiffness of said spring;

    the unitary coiled spring having a plurality of cross-sectional shapes, wherein a plurality of coil lengths of the spring have a first portion with a first cross-sectional shape that is substantially flat and a second portion with a second cross-sectional shape that is substantially circular with a given diameter, said substantially flat first cross-sections are diametrically opposed to said substantially circular second cross-sections, the first cross-sections being along a first longitudinal side of the coiled spring that is diametrically opposed to a second longitudinal side of the unitary coiled spring, and said substantially flat first cross-sections each have a length and a width shorter than the length, and said length extends substantially parallel to said corewire at its said protruding portion, said substantially parallel length being greater than the given diameter of said substantially circular second cross-sections, the second longitudinal side being longer than the first longitudinal side when respective flat first cross-section widths and circular second cross-sections of adjacent coil lengths engage each other, whereby the unitary coiled spring exhibits pre-shaped curvature bending; and

    a non-rotation system comprising a longitudinal pathway along one of said tube or corewire and a follower on the other of said tube or corewire, said follower being slidable with respect to said pathway and at least partially received within the pathway.

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