Steerable variable stiffness device

• US 5,531,685 A
• Filed: 08/01/1994
• Issued: 07/02/1996
• Est. Priority Date: 06/11/1993
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed, Inc. (Boston Scientific Corporation), Catheter Research Incorporated
• Original Assignee: Catheter Research Incorporated, Schneider Electric SE
• Inventors: Hemmer, Chad G., Forman, Michael R., Steen, John A., McGrath, Jonathan R.
• Primary Examiner(s): Yasko, John D.
• Assistant Examiner(s): CERMAK, ADAM
• Application Number:
  US08/284,076
• Time in Patent Office: 701 Days
• Field of Search: 604/95, 604/280-282, 600/143
• US Class Current: 604/95.05
• 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

An apparatus includes a flexible tubular member containing a shape-memory tube formed to include a lumen extending along the central axis of the tubular member. A liner sleeve extends through the lumen of the shape-memory tube and lies inside the tubular member. A control system selectively heats the shape-memory tube to its activated state causing the shape-memory tube to move toward a predetermined shape if it is different than its present configuration. Whether the shape-memory tube moves or not, it will increase significantly in stiffness, both axial and bending to help retain, hold, or wedge the apparatus in place in a selected body cavity while catheters or other objects are passed through a lumen in the liner sleeve.

Claims

1. An apparatus comprising

a flexible, elongated tubular member having a central axis extending therethrough,

a shape-memory tube made of temperature-activated shape-memory material and formed to include a lumen extending therethrough, the shape-memory tube being arranged in the tubular member to cause the lumen to extend along the central axis of the tubular member,

a liner sleeve positioned to extend through the lumen of the shape-memory tube and lie inside the tubular member, the liner sleeve being configured to have an annular exterior surface, and

control means for selectively heating the shape-memory tube to move the shape-memory tube to assume a stiff predetermined shape, thereby stiffening and moving the tubular member so that it moves toward a corresponding predetermined shape, the control means including a first electrically conductive coating around the liner sleeve, a second electrically conductive coating around the liner sleeve and positioned to lie in spaced-apart relation to the first electrically conductive coating, insulator means for preventing establishment of an electrical connection between the shape-memory tube and each of the first and second electrically conductive coatings, the insulator means being positioned to lie around the annular exterior surface of the liner sleeve and formed to include first and second openings, first conductor means passing through the first opening in the insulator means for electrically connecting the first electrically conductive coating to the shape-memory tube, and second conductor means passing through the second opening in the insulator means for electrically connecting the shape-memory tube to the second electrically conductive coating.

2. The apparatus of claim 1, wherein the liner sleeve and the shape-memory tube cooperate to define an annular space therebetween, the first electrically conductive coating is affixed to the liner sleeve, the second electrically conductive coating is affixed to the liner sleeve, and the insulator means is disposed in the annular space to lie around the first and second electrically conductive coatings and inside the lumen of the shape-memory tube.

3. The apparatus of claim 2, wherein the shape-memory tube has a cylindrical interior surface, the first electrically conductive coating has a concave interior surface affixed to the liner sleeve and a convex exterior surface facing toward the cylindrical interior surface of the shape-memory tube, and the first conductor means lies in said annular space and interconnects the convex exterior surface and the cylindrical interior surface.

4. The apparatus of claim 3, wherein the first conductor means is a curved strip of electrically conductive material.

5. The apparatus of claim 3, wherein the liner sleeve has an elongated cylindrical surface having a circumference and the first conductor means is a C-shaped curved strip positioned to extend around a semicircular portion of the circumference of the cylindrical exterior surface of the liner sleeve.

6. The apparatus of claim 3, wherein the first conductor means is formed of an electrically conductive material.

7. The apparatus of claim 3, wherein the second electrically conductive coating has a concave interior surface affixed to the liner sleeve and a convex exterior surface facing toward the cylindrical inner surface of the shape-memory tube and the second conductor means lies in said annular space in spaced-apart relation to the first conductor means and interconnects the convex exterior surface of the second electrically conductive coating and the cylindrical interior surface of the shape-memory tube.

8. The apparatus of claim 7, wherein the liner sleeve has an elongated cylindrical exterior surface having a circumference, the first conductor means is a C-shaped curved strip positioned to extend around a semicircular portion of the circumference of the cylindrical exterior surface of the liner sleeve, and the second conductor means is another C-shaped curved strip positioned to extend around an opposite semicircular portion of the circumference of the cylindrical exterior surface of the liner sleeve.

9. The apparatus of claim 7, wherein the shape-memory tube has spaced-apart first and second ends, the first conductor means is a first curved strip engaging the first end, and the second conductor means is a second curved strip engaging the second end.

10. The apparatus of claim 7, wherein the first conductor means is a first curved strip having first and second longitudinally extending edges and the insulator means includes a first curved end portion interconnecting the first and second longitudinally extending edges of the first curved strip and contacting both of the convex exterior surface of the second electrically conductive coating and the cylindrical interior surface of the shape-memory tube.

11. The apparatus of claim 10, wherein the second conductor means is a second curved strip having first and second longitudinally extending edges and the insulator means includes a second curved end portion interconnecting the first and second longitudinally extending edges of the second curved strip and contacting both of the convex exterior surface of the first electrically conductive coating and the cylindrical interior surface of the shape-memory tube and an elongated middle portion interconnecting the first and second curved end portions and contacting the convex exterior surfaces of the first and second electrically conductive coatings and the cylindrical interior surface of the shape-memory tube.

12. The apparatus of claim 1, wherein the first electrically conductive coating has a semicircular transverse cross-sectional shape.

13. The apparatus of claim 12, wherein the second electrically conductive coating has a semicircular transverse cross-sectional shape.

14. The apparatus of claim 1, wherein the insulator means is a cylindrical coating made of a dielectric material.

15. The apparatus of claim 14, wherein the insulator means is formed to position the first opening inside the lumen of the shape-memory tube and adjacent to one end of the shape-memory tube and to position the second opening inside the lumen of the shape-memory tube and adjacent to an opposite end of the shape-memory tube.

16. The apparatus of claim 1, wherein the first electrically conductive coating has a semicircular transverse cross-sectional shape and spaced-apart first and second longitudinally extending edges passing through the lumen of the shape-memory tube and adjacent to the liner sleeve, the second electrically conductive coating has a semicircular transverse cross-sectional shape and spaced-apart first and second longitudinally extending edges passing through the lumen of the shape-memory tube and adjacent to the liner sleeve, the first longitudinally extending edges of each of the first and second electrically conductive coatings are spaced apart to define a first longitudinally extending channel along an exterior surface of the liner sleeve, the second longitudinally extending edges of each of the first and second electrically conductive coatings are spaced apart to define a second longitudinally channel along an opposite side of the exterior surface of the liner sleeve, and the insulator means includes an elongated strip lying in each of the first and second longitudinally extending channels.

17. The apparatus of claim 16, wherein the second electrically conductive coating and the shape-memory tube are positioned to define an annular space therebetween, the first electrically conductive coating and the shape-memory tube are positioned to define another annular space therebetween, and the insulator means further includes a first curved end portion appended to each elongated strip and positioned to lie in the annular space located between the second electrically conductive coating and the shape-memory tube and a second curved end portion appended to each elongated strip and positioned to lie in said another annular space located between the first electrically conductive coating and the shape-memory tube.

18. The apparatus of claim 1, wherein the tubular member includes a distal tip positioned to lie in axially spaced-apart relation to the shape-memory tube and a tube-covering portion abutting the distal tip and containing the shape-memory tube therein, the distal tip is made of a first material having a first hardness, and the tube-covering portion is made of a second material having a second hardness greater than the first hardness.

19. The apparatus of claim 18, wherein the tubular member further includes a base portion lying in spaced-apart relation to the distal tip to position the tube-covering portion between the distal tip and the base portion and the base portion is made of a third material having a third hardness greater than the second hardness.

20. The apparatus of claim 19, further comprising a tubular braided sleeve formed to include a lumen receiving at least the liner sleeve therein and wherein the tubular braid sleeve includes an axially forward portion disposed in the tube-covering portion of the tubular member and an axially rearward portion disposed in the base portion of the tubular member.

21. The apparatus of claim 1, wherein the insulator means is formed to include an interior region receiving the shape-memory tube therein.

22. An apparatus comprising

an inner tubular member,

a first electrically conductive coating positioned to lie on an exterior surface of the inner tubular member,

a second electrically conductive coating positioned to lie on the exterior surface of the inner tubular member in spaced-apart relation to the first electrically conductive coating,

a shape-memory tube made of temperature-activated shape-memory material and formed to include a lumen extending therethrough, the inner tubular member and the first and second electrically conductive coatings extending through the lumen of the shape-memory tube,

means for coupling the shape-memory tube to the first and second electrically conductive coatings to establish an electrical circuit including in series a first conductive path through the first electrically conductive coating, a second conductive path through the shape-memory tube, and a third conductive path through the second electrically conductive coating,

an outer tubular member formed to include a lumen receiving the inner tubular member, the first and second electrically conductive coatings, the shape memory tube, and the coupling means therein, and

control means for applying an electrical potential to the first and second electrically conductive coatings to pass an electric current through the second conductive path through the shape-memory tube to heat the shape-memory tube so that the shape-memory tube moves toward a predetermined shape, thereby moving the outer tubular member toward a corresponding predetermined shape.

23. The apparatus of claim 22, wherein the first electrically conductive coating has a semicircular transverse cross-sectional shape.

24. The apparatus of claim 23, wherein the second electrically conductive coating has a semicircular transverse cross-sectional shape.

25. The apparatus of claim 22, wherein the shape-memory tube has a cylindrical interior surface and the first electrically conductive coating has a concave interior surface affixed to the exterior surface of the inner tubular member and a convex exterior surface facing toward the cylindrical interior surface of the shape-memory tube.

26. The apparatus of claim 25, wherein the coupling means is positioned to lie in said annular space and inside the lumen of the shape-memory tube.

27. The apparatus of claim 25, wherein the second electrically conductive coating has a concave interior surface affixed to the exterior surface of the tubular member and a convex exterior surface facing toward the cylindrical interior surface of the shape-memory tube.

28. The apparatus of claim 27, wherein the first and second electrically conductive coatings and the shape-memory tube cooperate to define an annular space therebetween and the coupling means is positioned to lie in said annular space and inside the lumen of the shape-memory tube.

29. The apparatus of claim 22, wherein the coupling means includes first conductor means for electrically connecting the first electrically conductive coating to the shape-memory tube, second conductor means for electrically connecting the second electrically conductive coating to the shape-memory tube, and an insulator between the shape-memory tube and each of the first and second conductor means.

30. The apparatus of claim 29, wherein the first conductor means is a curved strip of electrically conductive material.

31. The apparatus of claim 29, wherein the inner tubular member has an elongated cylindrical surface having a circumference and the first conductor means is a C-shaped curved strip positioned to extend around a semicircular portion of the circumference of the cylindrical exterior surface of the inner tubular member.

32. The apparatus of claim 29, wherein the first conductor means is formed of an electrically conductive material.

33. The apparatus of claim 29, wherein the liner sleeve has an elongated cylindrical exterior surface having a circumference, the first conductor means is a C-shaped curved strip positioned to extend around a semicircular portion of the circumference of the cylindrical exterior surface of the liner sleeve, and the second conductor means is another C-shaped curved strip positioned to extend around an opposite semicircular portion of the circumference of the cylindrical exterior surface of the liner sleeve.

34. The apparatus of claim 29, wherein the first conductor means is a first curved strip having first and second longitudinally extending edges and the insulator includes a first curved end portion interconnecting the first and second longitudinally extending edges of the first curved strip and contacting both of the convex exterior surface of the second electrically conductive coating and the cylindrical interior surface of the shape-memory tube.

35. The apparatus of claim 34, wherein the second conductor means is a second curved strip having first and second longitudinally extending edges and the insulator includes a second curved end portion interconnecting the first and second longitudinally extending edges of the second curved strip and contacting both of the convex exterior surface of the first electrically conductive coating and the cylindrical interior surface of the shape-memory tube and an elongated middle portion interconnecting the first and second curved end portions and contacting the convex exterior surfaces of the first and second electrically conductive coatings and the cylindrical interior surface of the shape-memory tube.

36. An apparatus comprising

a shape-memory tube made of shape-memory material and formed to include a lumen extending therethrough,

an inner tubular member extending through the lumen of the shape-memory tube,

a first electrically conductive coating on the inner tubular member,

a second electrically conductive coating on the inner tubular member,

a dielectric coating lying in the lumen of the shape-memory tube and electrically separating the first and second electrically conductive coating from one another and from the shape-memory tube,

a first electrical conductor interconnecting the first electrically conductive coating and the shape-memory tube and passing through the dielectric coating,

a second electrical conductor interconnecting the second electrically conductive coating and the shape-memory tube and passing through the dielectric coating, and

an outer tubular member formed to include a lumen receiving the inner tubular member, the first and second electrically conductive coatings, the dielectric coating, the first and second electrical conductors, and the shape-memory tube.

37. The apparatus of claim 36, wherein the first and second electrical conductors are positioned to lie in the lumen of the shape-memory tube.

38. The apparatus of claim 37, wherein at least one of the first and second electrical conductors is a curved strip of electrically conductive material.

39. The apparatus of claim 37, wherein at least one of the electrical conductors is formed of an electrically conductive material.

40. The apparatus of claim 36, wherein the first electrically conductive coating has a semicircular transverse cross-sectional shape.

41. The apparatus of claim 40, wherein the second electrically conductive coating has a semicircular transverse cross-sectional shape.

42. The apparatus of claim 36, wherein the inner tubular member has an elongated cylindrical surface having a circumference and the first electrical conductor is a C-shaped curved strip positioned to extend around a semicircular portion of the circumference of the cylindrical exterior surface of the inner tubular member.

43. An apparatus comprising

a flexible, elongated tubular member having a central axis extending therethrough,

a shape-memory tube made of temperature-activated shape-memory material and formed to include a lumen extending therethrough, the shape-memory tube being arranged in the tubular member to cause the lumen to extend along the central axis of the tubular member, the shape-memory tube having a certain modulus of elasticity at a predetermined temperature,

a liner sleeve positioned to extend through the lumen of the shape-memory tube and lie inside the tubular member, the liner sleeve being configured to have an annular exterior surface, and

control means for selectively heating the shape-memory tube to a temperature in excess of the predetermined temperature to stiffen the shape-memory tube so that it has a modulus of elasticity that is greater than the certain modulus of elasticity and assumes a stiff predetermined shape, thereby stiffening the tubular member, the control means including a first electrically conductive coating around the liner sleeve, a second electrically conductive coating around the liner sleeve and positioned to lie in spaced-apart relation to the first electrically conductive coating, insulator means for preventing establishment of an electrical connection between the shape-memory tube and each of the first and second electrically conductive coatings, the insulator means being positioned to lie around the annular exterior surface of the liner sleeve and formed to include first and second openings, first conductor means passing through the first opening in the insulator means for electrically connecting the first electrically conductive coating to the shape-memory tube, and second conductor means passing through the second opening in the insulator means for electrically connecting the shape-memory tube to the second electrically conductive coating.

44. The apparatus of claim 43, wherein the liner sleeve and the shape-memory tube cooperate to define an annular space therebetween, the first electrically conductive coating is affixed to the liner sleeve, the second electrically conductive coating is affixed to the liner sleeve, and the insulator means is disposed in the annular space to lie around the first and second electrically conductive coatings and inside the lumen of the shape-memory tube.

45. The apparatus of claim 43, wherein the first electrically conductive coating has a semicircular transverse cross-sectional shape.

46. The apparatus of claim 45, wherein the second electrically conductive coating has a semicircular transverse cross-sectional shape.

47. The apparatus of claim 43, wherein the insulator means is a cylindrical coating made of a dielectric material.

48. The apparatus of claim 43, wherein the first electrically conductive coating has a semicircular transverse cross-sectional shape and spaced-apart first and second longitudinally extending edges passing through the lumen of the shape-memory tube and adjacent to the liner sleeve, the second electrically conductive coating has a semicircular transverse cross-sectional shape and spaced-apart first and second longitudinally extending edges passing through the lumen of the shape-memory tube and adjacent to the liner sleeve, the first longitudinally extending edges of each of the first and second electrically conductive coatings are spaced apart to define a first longitudinally extending channel along an exterior surface of the liner sleeve, the second longitudinally extending edges of each of the first and second electrically conductive coatings are spaced apart to define a second longitudinally channel along an opposite side of the exterior surface of the liner sleeve, and the insulator means includes an elongated strip lying in each of the first and second longitudinally extending channels.

49. The apparatus of claim 43, wherein the tubular member includes a distal tip positioned to lie in axially spaced-apart relation to the shape-memory tube and a tube-covering portion abutting the distal tip and containing the shape-memory tube therein, the distal tip is made of a first material having a first hardness, and the tube-covering portion is made of a second material having a second hardness greater than the first hardness.

50. The apparatus of claim 43, wherein the insulator means is formed to include an interior region receiving the shape-memory tube therein.