Guidewire having selectively adjustable stiffness and tip curvature

摘要

A guidewire assembly having selectively adjustable stiffness and tip curvature includes a hollow guidewire having a distal portion terminating at a distal tip, a curvature-modifying element anchored to the distal tip, and a stiffness-modifying element displaceable within the hollow guidewire towards and away from the distal tip so as to vary a stiffness of the distal portion. The stiffness-modifying element and the curvature-modifying element are frictionally linked such that movement of the stiffness-modifying element from a current position over a first range of motion causes corresponding displacement of the curvature-modifying element, thereby modifying a state of curvature of at least part of the distal portion of the guidewire. Movement of the stiffness-modifying element beyond the first range of motion displaces the stiffness-modifying element relative to the curvature-modifying element.

主权项

1. An apparatus comprising:
(a) a hollow guidewire having a distal portion terminating at a distal tip, at least part of said distal portion being formed as a helical spring biased to assume a deflected form; (b) a curvature-modifying element anchored to said distal tip and extending proximally from said distal tip through at least said distal portion of said guidewire, said distal portion and said curvature-modifying element being configured such that axial displacement of said curvature-modifying element within a first range of motion modifies a state of curvature of said at least part of said distal portion of the guidewire, refraction of said curvature-modifying element being effective to straighten said at least part of said distal portion by closing together successive coils of said helical spring; and (c) a stiffness-modifying element displaceable within said hollow guidewire towards and away from said distal tip so as to vary a degree of overlap between said stiffness-modifying element and said distal portion, thereby varying a stiffness of said distal portion,wherein said stiffness-modifying element and said curvature-modifying element are frictionally linked such that:
(i) movement of said stiffness-modifying element from a current position over a first range of motion causes corresponding displacement of said curvature-modifying element, thereby modifying a state of curvature of at least part of said distal portion of the guidewire, said stiffness-modifying element and said curvature-modifying element being configured to create therebetween sufficient frictional engagement that retraction of said stiffness-modifying element applies sufficient frictional force to said curvature-modifying element to fully straighten said at least part of said distal portion; and (ii) movement of said stiffness-modifying element beyond said first range of motion overcomes said frictional engagement so as to displace said stiffness-modifying element relative to said curvature-modifying element.