Steerable guidewire and method of use
This invention is a transvascularly placed steerable guidewire, further including internal steerability and the ability to articulate in a direction at right angles to its longitudinal axis at or near its distal end. The steerable guidewire is generally fabricated from stainless steel and includes an outer tube, an inner tube, hub structures, and a distal articulating region. The steerable guidewire can be advanced through a body lumen in its straight configuration and then be selectively articulated or curved to permit negotiation of tortuous curvature. The steerable guidewire hub can be removed to permit advancement of catheters over its proximal end followed by re-attachment of the hub to permit deflection of the distal end of the steerable guidewire. Removal of the hub can result in a limp guidewire or maintenance of a forced curvature of the distal end of the guidewire.
1. A steerable guidewire comprising:
an inner tube characterized by a proximal and a distal end, said inner tube having a flexible region near the distal end thereof;
an outer tube characterized by a proximal end, a distal end, and a flexible region at the distal end, said flexible region also characterized by a proximal and a distal end,
said inner tube longitudinally fixed to the outer tube at a point in the outer tube proximate the distal end of the flexible region of the outer tube;
a hub releasably affixed to the proximal end of the inner tube and the proximal end of the outer tube and comprising a hub body and a control knob with a hub lumen passing through the hub;
a jack-screw traveler element affixed to the proximal end of the inner tube, wherein the jack-screw traveler element comprises a traveler thread, wherein the outer tube can be tensioned axially relative to the hub and the inner tube in response to movement of the jack-screw traveler element;
wherein the hub lumen is configured for receiving the jack-screw traveler element and preventing the jack-screw traveler element from moving along the longitudinal axis of the hub, and wherein the outer tube is constrained not to move longitudinally relative to the hub; and
wherein the knob is capable of being rotated by a user, to rotate the traveler element; and the apparatus further comprises:
features operable to prevent longitudinal motion of the inner tube relative to the outer tube upon removal of the hub.
2. The steerable guidewire of claim 1 wherein longitudinal movement of the outer tube relative to the inner tube causes distortion of the outer tube in a region of laterally oriented slots and results in selective bending of the outer tube and inner tube in the region of the laterally oriented slots.
3. The steerable guidewire of claim 1 wherein the distal end of the outer tube can controllably curve between about 0 degrees and at least about 180 degrees from the longitudinal axis of the outer tube.
4. The steerable guidewire of claim 1 wherein an outer diameter of the steerable guidewire is approximately the same along a length of the steerable guidewire.
5. The steerable guidewire of claim 1 wherein the features operable to prevent longitudinal motion comprise spring loaded pins disposed within the inner tube that engage openings in a wall of the inner tube or a wall of the outer tube, or both.
6. The steerable guidewire of claim 1 wherein the features operable to prevent longitudinal motion comprise leaf springs integral with the inner tube that engage the proximal end of the outer tube.
7. The steerable guidewire of claim 1 further comprising a catheter configured to be routed alongside the guidewire by means of fasteners that open and close around the outer tube.
8. The steerable guidewire of claim 1 further comprising a locking collar that protrude from the inner tube, proximate a proximal end of the apparatus such that the hub can engage the features and lock thereto.
9. The steerable guidewire of claim 1 further comprising a removable obturator slidably disposed within the lumen of the inner tube, wherein the obturator can be advanced forward out the distal end of the inner tube or it can be removed from the inner tube by withdrawal through the proximal end of the inner tube.
10. The steerable guidewire of claim 1 wherein the flexible portion of the outer tube comprises a plurality of approximately laterally oriented slots.
11. The steerable guidewire of claim 1 wherein the inner tube imparts off-center forces due to a discontinuity in a structure of the inner tube.
12. The steerable guidewire of claim 1 wherein the outer tube is a composite and comprises coils of wire along at least a portion of its length.
13. The steerable guidewire of claim 1 wherein the inner tube comprises a protrusion near its proximal end and the outer tube comprises a longitudinal slot having one or more cul-de-sacs wherein the protrusion on the inner tube can move longitudinally or axially within the longitudinal slot in the outer tube and rest within the one or more cul-de-sacs such that further longitudinal movement of the inner tube relative to the outer tube is prevented.
14. The steerable guidewire of claim 1 wherein the features operable to prevent longitudinal motion comprise an outward protrusion on the inner tube and an opening on the outer tube configured to receive the outward protrusion.