Medical instrument with controlled torque transmission

• US 20040220499A1
• Filed: 05/01/2003
• Published: 11/04/2004
• Est. Priority Date: 05/01/2003
• Status: Active Grant

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: Scimed Life Systems Incorporated (Boston Scientific Corporation)
• Inventors: Griego, John A., Weststrate, Patrice A.
• Granted Patent: US 7,780,611 B2
• Time in Patent Office: Days
• US Class Current: 600/585
• CPC Class Codes: A61M 2025/09108 Methods for making a guide wire
• CPC Class Codes: A61M 2025/09175 having specific characteristics at the distal tip
• CPC Class Codes: A61M 25/09 Guide wires
• CPC Class Codes: A61M 25/09033 with fixed mandrils, e.g. mandrils fixed to tip; Tensionable wires
• CPC Class Codes: Y10T 29/49 Method of mechanical manufacture

Abstract

A medical instrument such as a guidewire that is designed to have controlled torque transmission along its length. Specially treated areas are placed in selected and equal areas along the entire length of the elongated shaft of the medical instrument, and are separated from one another by untreated areas. This process ensures that any torque is transmitted distally, in a smooth manner, regardless of the guidewire position, thus resulting in a substantial reduction in whipping. In one embodiment, a stainless steel guidewire is utilized, and is subjected to annealing heat treatment in selected areas. This annealing process creates a mandrel that has repeated temper properties along its length. Torque applied at one end of this mandrel is transmitted to the opposite end in an even and controlled manner, even when the mandrel is formed into a loop.

Claims

1. An elongated medical instrument that is subject to torque when in use, comprising:

a first plurality of sections that have been subjected to a selected treatment process;

a second plurality of sections located between each of the sections of the first plurality of sections, the second plurality of sections not having been subjected to the selected treatment process; and

wherein the first plurality of sections and the second plurality of sections have different torque transmission characteristics.

2. The medical instrument of claim 1, wherein the selected treatment process is a heat treatment process.

3. The medical instrument of claim 2, wherein the heat treatment process is an annealing process.

4. The medical instrument of claim 3, wherein the second plurality of sections are normally tempered.

5. The medical instrument of claim 1, wherein each of the sections in the first plurality of sections are approximately the same length.

6. The medical instrument of claim 5, wherein each of the sections in the second plurality of sections are approximately the same length.

7. The medical instrument of claim 6, wherein each of the sections in the second plurality of sections is approximately twice as long as the sections in the first plurality of sections.

8. The medical instrument of claim 1, wherein the medical instrument comprises stainless steel.

9. The medical instrument of claim 1, wherein the medical instrument is tapered along at least part of its length.

10. The medical instrument of claim 1, wherein the medical instrument is a guidewire.

11. An elongated medical instrument comprising an elongated structural body, the body having repeated temper properties along its length, the repeated temper properties including annealed properties interspersed with normally tempered properties.

12. The medical instrument of claim 11, wherein the annealed properties are contained in sections of the structural body that are separated by sections having the normally tempered properties.

13. The medical instrument of claim 11, wherein the structural body is tapered along at least part of its length.

14. The medical instrument of claim 11, wherein the sections of the structural body that have the normally tempered properties are at least as long as the sections of the body that have the annealed properties.

15. A method for treating an elongated medical instrument, comprising:

preparing a heating process for heating a plurality of selected sections of the medical instrument; and

subjecting the plurality of selected sections of the medical instrument to the heating process so as to alter the torque characteristics of the plurality of selected sections, the plurality of selected sections of the medical instrument being separated from one another by a plurality of unselected sections that are not subjected to the heating process.

16. The method of claim 15, wherein the medical instrument is formed of stainless steel and the heating process raises the temperature of the plurality of selected sections above approximately 1200°

F.

17. The method of claim 15, wherein the plurality of unselected sections that are not subjected to the heating process are protected from the heating process.

18. The method of claim 17, wherein the plurality of unselected sections are protected from the heating process by heat sinks.

19. The method of claim 15, wherein the heating process is followed by a quick quench process.

20. The method of claim 15, wherein each of the sections in the plurality of selected sections is approximately the same length.