Steerable catheter with adjustable bend location and/or radius and method

• US 5,391,147 A
• Filed: 11/05/1993
• Issued: 02/21/1995
• Est. Priority Date: 12/01/1992
• Status: Expired due to Fees

• Current Assignee: Cardiac Pathways Corp. (Boston Scientific Corporation)
• Original Assignee: Cardiac Pathways Corp. (Boston Scientific Corporation)
• Inventors: Imran, Mir A., Glynn, Brian A., Pomeranz, Mark L.
• Primary Examiner(s): Yasko, John D.
• Assistant Examiner(s): WILKENS, FRANK
• Application Number:
  US08/147,753
• Time in Patent Office: 473 Days
• Field of Search: 604/95, 604/281, 128/656-658, 128/772
• US Class Current: 604/528
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2017/003 Steerable
• CPC Class Codes: A61B 2017/00867 shape memory effect for prostheses A61F2210/0014
• CPC Class Codes: A61B 2018/00351 Heart
• CPC Class Codes: A61B 2018/00577 Ablation
• CPC Class Codes: A61B 2018/0091 Handpieces of the surgical instrument or device
• CPC Class Codes: A61B 2018/00916 with means for switching or controlling the main function of the instrument or device
• CPC Class Codes: A61B 2018/00946 slidable
• CPC Class Codes: A61B 2018/1253 monopolar
• CPC Class Codes: A61B 2018/1467 using more than two electrodes on a single probe
• CPC Class Codes: A61M 25/0136 Handles therefor
• CPC Class Codes: A61M 25/0144 having flexible regions as a result of inner reinforcement means, e.g. struts or rods
• CPC Class Codes: A61M 25/0147 with movable mechanical means, e.g. pull wires
• CPC Class Codes: A61M 25/0158 with magnetic or electrical means, e.g. by using piezo materials, electroactive polymers, magnetic materials or by heating of shape memory materials

Abstract

A steerable catheter comprising a flexible elongate tubular member having proximal and distal extremities, a handle secured to the proximal extremity, said tubular member having a lumen extending therethrough, a mandrel slidably mounted in the lumen and extending into the distal extremity and means extending through the tubular member for causing a bending of the distal extremity with respect to the mandrel disposed therein.

Claims

1. A steerable catheter comprising a flexible elongate tubular member having proximal and distal extremities, a handle secured to the proximal extremity, said tubular member having a lumen extending therethrough, a mandrel slidably mounted in the lumen and extending into the distal extremity and means extending through the tubular member for causing bending of the distal extremity with respect to the mandrel disposed therein, said mandrel having a portion of reduced stiffness so that the bend location can be selected depending upon the position of the region of reduced thickness.

2. A steerable catheter comprising a flexible elongate tubular member having proximal and distal extremities, a handle secured to the proximal extremity, said tubular member having a lumen extending therethrough, a mandrel slidably mounted in the lumen and extending into the distal extremity and means extending through the tubular member for causing bending of the distal extremity with respect to the mandrel disposed therein and memory means carried by the distal extremity of the flexible elongate tubular member having a memory which wishes to assume a straight shape to aid in returning the distal extremity of the flexible elongate member to a straight shape when the pull wire is released.

3. A catheter as in claim 2 wherein said memory means assuming a straight shape is comprised of a superelastic material in ribbon form having a width and a thickness and permitting bending of the ribbon in a direction which is perpendicular to the surface forming the width of the ribbon.

4. A steerable catheter comprising a flexible elongate tubular member having proximal and distal extremities, a handle secured to the proximal extremity, said tubular member having a lumen extending therethrough, a mandrel slidably mounted in the lumen and extending into the distal extremity, means extending through the tubular member for causing bending of the distal extremity with respect to the mandrel disposed therein together with means carried by the handle for advancing and retracting the mandrel, said means carded by the handle for advancing and retracting the mandrel including a pin secured to the proximal extremity of the mandrel and a sleeve carried by the handle and rotatably mounted on the handle and means coupled to the sleeve and to the pin for causing longitudinal movement of the pin with respect to the handle upon rotation of the sleeve.

5. A steerable catheter comprising a flexible elongate tubular member having proximal and distal extremities, a handle secured to the proximal extremity, said flexible elongate tubular member comprising an inner shaft having at least one lumen extending therethrough, a coaxial sleeve mounted on the shaft, at least a portion of said shaft having a twist provided therein and a means for securing said sleeve to said shaft at opposite ends of said portion to retain said twist in said shaft, a pull wire extending through said at least one lumen and connected to the distal extremity of the flexible elongate tubular member and means carried by the handle and secured to the pull wire for retracting and advancing said pull wire, said sleeve being formed of a material having good torque transmitting properties, said pull wire being used for placing a bend in the distal extremity of the flexible elongate tubular member, said twist in said portion of said shaft serving to prevent the pull wire from selecting a preferred orientation when said portion of the shaft is formed into a bend.

6. A catheter as in claim 5 wherein said twist extends through substantially 360°

.

7. A catheter as in claim 5 wherein said portion of the shaft has a length of approximately 15".

8. A catheter as in claim 5 wherein said shaft is provided with a central lumen, a mandrel slidably mounted in said central lumen and extending to the distal extremity and means carried by the handle and secured to the mandrel for advancing and retracting the mandrel in the central lumen.

9. A catheter as in claim 8 wherein the at least one lumen for the pull wire is offset with respect to the central lumen.

10. In a steerable catheter having an adjustable bend location, a flexible elongate tubular member having proximal and distal extremities, a plurality of circumferentially spaced-apart flexible elements disposed in the distal extremity for causing bending of the distal extremity of the flexible elongate member and movable means disposed at the distal extremity of the flexible elongate member for selecting the location in the distal extremity where bending is to occur to thereby adjust the length of the flexible elongate member which extends beyond the bend, said movable means being in the form of a shape-memory element having a memory which makes it assume a straight position upon the application of an electrical current thereto and bypass means adjustable longitudinally of the shape-memory element for causing the current applied to the shape-memory element to bypass a portion of the length of the shape-memory element so that it remains flexible at that portion to provide a hinge point for the bend.

11. A catheter as in claim 10 wherein said bypass means consists of a conductive sleeve movable longitudinally of the shape-memory element.

12. A catheter as in claim 11 wherein said sleeve is in the form of conductive mesh of a highly conductive material.

13. A catheter as in claim 11 together with means coupled to said sleeve for moving said sleeve longitudinally of said shape-memory element, said means coupled to the sleeve extending to the proximal extremity of the flexible elongate member.

14. A catheter as in claim 13 together with a control mechanism mounted on the proximal extremity of the flexible elongate member, said control mechanism including a control member movable longitudinally thereof and connected to the member coupled to the sleeve.

15. A catheter as in claim 13 wherein said means coupled to said sleeve is in the form of a tubular member having a bore therein and wherein said shape-memory element extends through said bore.

16. In a steerable catheter having an adjustable bend location, a flexible elongate tubular member having proximal and distal extremities, a plurality of circumferentially spaced-apart flexible elements disposed in the distal extremity for causing bending of the distal extremity of the flexible elongate member and movable means disposed at the distal extremity of the flexible elongate member for selecting the location in the distal extremity where bending is to occur to thereby adjust the length of the flexible elongate member which extends beyond the bend, said movable means being in the form of a plurality of stiffening elements, each having a weakened region providing a hinge point in a different longitudinal position of the stiffening element than the longitudinal positions of the other said stiffening elements.

17. A catheter as in claim 16 wherein said stiffening element is comprised of an elongate flexible member of a predetermined cross-section and wherein said weakened region is formed by producing a region of reduced cross-section.

18. In a steerable catheter having an adjustable bend location, a flexible elongate tubular member having proximal and distal extremities, a plurality of circumferentially spaced-apart flexible elements disposed in the distal extremity for causing bending of the distal extremity of the flexible elongate member and movable means disposed at the distal extremity of the flexible elongate member for selecting the location in the distal extremity where bending is to occur to thereby adjust the length of the flexible elongate member which extends beyond the bend, said movable means being in the form of a telescoping assembly movable between collapsed and extended positions comprising at least first and second telescoping members telescopically mounted with respect to each other disposed in the distal extremity of the flexible elongate member, flexible elongate means extending to the proximal extremity of the flexible elongate member and coupled to said second telescoping member of said telescoping assembly for moving said telescoping assembly between said collapsed and extended positions, said flexible elongate means coupled to said telescoping assembly including a weakened longitudinal portion which forms a hinge point.

19. A method for adjusting the bend location in a steerable catheter having a distal extremity, providing stiffening means within the distal extremity of the catheter, providing a hinge point in the stiffening means and adjusting the location of the hinge point longitudinally of the stiffening means to adjust the position of the hinge point whereby the length of the distal extremity of the catheter extending beyond the hinge point can be adjusted.

20. A method for preventing whipping of the distal extremity of a steerable catheter as the steerable catheter is rotated when a bend has been placed in the distal extremity of the steerable catheter of the type which is provided with an elongate shaft and having a centrally disposed lumen therein extending therethrough and an additional lumen disposed therein offset from the centrally disposed lumen and a coaxially mounted sleeve mounted on said shaft comprising imparting a twist to at least a portion of the shaft and securing opposite sides of the portion of the shaft having the portion therein to the sleeve to retain the twist in the shaft and placing a pull wire in the additional lumen in the shaft and secured to the distal extremity.

21. A method as in claim 20 together with the step of positioning a mandrel within the central lumen adjusting the position of the mandrel to adjust the radius of the bend placed in the distal extremity of the catheter as the pull wire is retracted.

22. A method as in claim 20 together with the step of placing a member in the distal extremity of the catheter having a superelastic memory in the form of a straight shape so that when the pull wire is advanced, the distal extremity of the catheter assumes a straight shape under the urging of the superelastic memory member.

23. A method as in claim 22 together with the step of forming the number having a superelastic memory into the form of a ribbon and orienting the ribbon so that the distal extremity of the flexible elongate tubular member will only bend in a direction toward the pull wire which is perpendicular to the width of the ribbon.