Expandable fixation structures

• US 20060095077A1
• Filed: 10/29/2004
• Published: 05/04/2006
• Est. Priority Date: 10/29/2004
• Status: Abandoned Application

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Tronnes, Carole A.
• Application Number:
  US10/977,330
• Publication Number:
  US 20060095077A1
• Time in Patent Office: Days
• US Class Current: 607/2
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/37518 Anchoring of the implants, e.g. fixation
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators

Abstract

In general, the invention is directed to a medical device implantable in a body of a patient. The medical device includes a non-expandable element, constructed of a biocompatible material such as silicone or polyurethane. The device also includes one or more expandable elements constructed of a hydrogel material. During implantation, the expandable elements are in a small, dehydrated state. When implanted in the body of a patient, the expandable elements absorb water from the body tissues and assume a larger, hydrated state, and resist migration of the implanted device.

Claims

1. An implantable medical device comprising:

a non-expandable element; and

a hydrogel element coupled to the non-expandable element;

wherein the hydrogel element has a first perimeter in a dehydrated state and a second perimeter in a hydrated state, and

wherein the hydrogel element is configured to expand from the first perimeter to the second perimeter when the hydrogel element is in contact with a body fluid of a patient.

2. The device of claim 1, wherein the hydrogel element is a first hydrogel element, the device further comprising a second hydrogel element coupled to the non-expandable element and configured to expand from a dehydrated state to a hydrated state.

3. The device of claim 2, wherein the non-expandable element has a proximal end and a distal end, wherein the first hydrogel element is coupled to the proximal end, and the second hydrogel element is coupled to the distal end.

4. The device of claim 1, wherein the non-expandable element is constructed of at least one of polyurethane, silicone, titanium, stainless steel, fluoropolymer or hydrogel.

5. The device of claim 1, wherein the non-expandable element is substantially cylindrical and has a diameter from approximately one millimeter to approximately seven millimeters.

6. The device of claim 1, wherein the length of the device is from ten millimeters to twenty millimeters.

7. The device of claim 1, wherein the second perimeter is approximately two times to five times larger than the first perimeter.

8. The device of claim 1, further comprising an electrode coupled to the non-expandable element.

9. The device of claim 8, further comprising a lead comprising a conductor electrically coupled to the electrode.

11. The device of claim 8, further comprising a pulse generator coupled to the electrode, wherein the pulse generator is housed inside the non-expandable element.

13. The device of claim 1, wherein the non-expandable element is a first non-expandable element and wherein the hydrogel element is a first hydrogel element, the device further comprising:

a second non-expandable element coupled to the first hydrogel element; and

a second hydrogel element coupled to the second non-expandable element.

14. The device of claim 1, further comprising a sensor coupled to the non-expandable element, wherein the sensor is configured to sense at least one of pressure, flow, temperature, fluid level, contractile force, pH or chemical concentration.

10. (canceled)

12. (canceled)

15. An implantable electrical stimulation device comprising:

a non-expandable element housing an implantable pulse generator; and

a hydrogel element coupled to the non-expandable element;

wherein the hydrogel element is configured to expand from a dehydrated state to a hydrated state.

16. The device of claim 15, further comprising a processor configured to control the pulse generator, wherein the non-expandable element houses the processor.

17. The device of claim 15, further comprising a lead comprising a conductor electrically coupled to the pulse generator.

19. The device of claim 15, wherein the non-expandable element is substantially cylindrical and has a diameter from approximately one millimeter to approximately seven millimeters.

20. The device of claim 15, wherein the length of the device is from ten millimeters to twenty millimeters.

21. The device of claim 15, wherein the hydrogel element is configured to expand in dimension approximately two times to five times when expanding from the dehydrated state to the hydrated state.

18. (canceled)

22-27. -27. (canceled)

28. An implantable medical device comprising:

non-expandable element means; and

expandable element means coupled to the non-expandable element means;

wherein the expandable element means is configured to expand from a first perimeter to a second perimeter when the expandable element means is in contact with a body fluid of a patient.

29. The device of claim 28, further comprising an electrode means coupled to the non-expandable element means, and a stimulating means coupled to the electrode means.

31. The device of claim 28, wherein the device is a substantially rice-shaped device prior to expansion of the expandable element means from the first perimeter to the second perimeter.

32. The device of claim 28, wherein the device is a substantially dumbbell-shaped device after the expansion of the expandable element means from the first perimeter to the second perimeter.

33. The device of claim 28, wherein the non-expandable element means is substantially cylindrical and has a diameter from approximately one millimeter to approximately seven millimeters.

34. The device of claim 28, wherein the length of the device is from ten millimeters to twenty millimeters.

35. The device of claim 28, wherein the expandable element means is configured such that the second perimeter is approximately two times to five times larger than the first perimeter.

30. (canceled)

36. A method for implanting a medical device, comprising:

placing a medical device into a bore of an insertion device, the medical device including a non-expandable element and a hydrogel element coupled to the non-expandable element, the hydrogel element being in a dehydrated state;

inserting the insertion device into the body of a patient; and

ejecting the medical device from the insertion device proximate to a target tissue,

wherein the hydrogel element is configured to expand from the first perimeter to the second perimeter when the hydrogel element is ejected from the insertion device.

37. The method of claim 36, wherein the medical device comprises an implantable neurostimulator or an implantable physiological sensor.

39. The method of claim 36, wherein the insertion device comprises one of a needle, a hollow trocar, an endoscope, a catheter or a cannula.

38. (canceled)

40. An implantable electrical stimulation device comprising:

a non-expandable element housing a sensor; and

a hydrogel element coupled to the non-expandable element;

wherein the hydrogel element is configured to expand from a dehydrated state to a hydrated state.

41. The device of claim 40, wherein the sensor is configured to sense at least one of pressure, flow, temperature, fluid level, contractile force, pH or chemical concentration.

43. The device of claim 40, wherein the non-expandable element is substantially cylindrical and has a diameter from approximately one millimeter to approximately seven millimeters.

44. The device of claim 40, wherein the length of the device is from ten millimeters to twenty millimeters.

45. The device of claim 40, wherein the hydrogel element is configured to expand in dimension approximately two times to five times when expanding from the dehydrated state to the hydrated state.

42. (canceled)