THERMAL MANAGEMENT OF IMPLANTABLE MEDICAL DEVICES

• US 20090192575A1
• Filed: 01/22/2009
• Published: 07/30/2009
• Est. Priority Date: 01/29/2008
• Status: Active Grant

• Current Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Original Assignee: Boston Scientific Neuromodulation Corporation (Boston Scientific Corporation)
• Inventors: Carbunaru, Rafael, DiGiore, Andrew, Schleicher, Brett
• Granted Patent: US 8,165,694 B2
• Time in Patent Office: Days
• US Class Current: 607/61
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/3787 from an external energy source
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/15 using ultrasonic waves
• CPC Class Codes: H02J 50/30 using light, e.g. lasers
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction

Abstract

Systems and techniques for thermal management of implantable medical devices. In one aspect an implantable device includes an active component configured to perform medical activities, a charging component configured to convert energy from outside a body in which the implantable device is implanted into potential energy, and a thermal barrier between the charging component and the active portion. The thermal barrier thermally isolates the charging component from the active portion so that thermal resistance between the charging component and the active component is above the thermal resistance between the charging component and the body.

Claims

1. An implantable device comprising:

an active component configured to perform medical activities;

a charging component configured to convert energy from outside a body in which the implantable device is implanted into potential energy; and

a thermal barrier between the charging component and the active portion,

wherein the thermal barrier thermally isolates the charging component from the active portion so that thermal resistance between the charging component and the active component is above the thermal resistance between the charging component and the body.

2. The implantable device of claim 1, wherein the thermal conductance between the charging component and the body is 1.5 or more times the thermal conductance between the charging component and the active component.

3. The implantable device of claim 1, wherein the active component comprises an implantable pulse generator configured to deliver electrical pulses to tissue.

4. The implantable device of claim 1, wherein the implantable pulse generator comprises a microstimulator.

5. The implantable device of claim 1, wherein the charging component comprises a coil configured to respond to an electric or magnetic field generated outside the body.

6. The implantable device of claim 1, wherein:

the implantable device further comprises a lead that allows the active component to access the potential energy from the charging component; and

the thermal barrier comprises a separation between the active component and the charging component spanned by the lead.

7. The implantable device of claim 6, wherein the lead comprises a flexible lead that flexes when subject to physiological-scale stresses associated with implantation.

8. The implantable device of claim 6, wherein:

the active component comprises an implantable pulse generator configured to deliver electrical pulses to tissue; and

the charging component comprises an electrode that is electrically connected to the implantable pulse generator for delivery of the electrical pulses.

9. The implantable device of claim 1, wherein the charging component comprises a flapped appendage that is mechanically joined to the active component at the thermal barrier.

10. The implantable device of claim 9, wherein the thermal barrier has a smaller area than an area of barriers that isolate the charging component from the body.

11. The implantable device of claim 1, wherein the charging component comprises:

a first flapped appendage that is mechanically joined to the active component at a first thermal barrier; and

a second flapped appendage that is mechanically joined to the active component at a second thermal barrier.

12. The implantable device of claim 1, wherein the active component comprises circuitry to manage performance of the medical activities.

13. An implantable device comprising:

an implantable pulse generator configured to deliver electrical pulses to tissue of a body over one or more electrodes, the implantable pulse generator comprising

a thermally insensitive portion that comprises a charging component configured to convert energy from outside a body in which the implantable pulse generator is implanted into potential energy, wherein the conversion is accompanied by a change in temperature,

a thermally sensitive portion that comprises a component whose function or lifespan can be impaired by the change in temperature accompanying the conversion of energy from outside the body into potential energy by the charging component, and

a thermal barrier between the thermally insensitive portion and the thermally sensitive portion, wherein the thermal barrier thermally isolates the thermally insensitive portion from the thermally sensitive portion so that thermal resistance between the thermally insensitive portion and the thermally sensitive portion is above the thermal resistance between the thermally insensitive portion and the body.

14. The implantable device of claim 13, wherein the thermal conductance between the thermally insensitive portion and the body is 1.5 or more times the thermal conductance between the thermally insensitive portion and the thermally sensitive portion.

15. The implantable device of claim 13, wherein:

the implantable device further comprises a lead that allows the thermally sensitive portion to access the potential energy from the charging component; and

the thermal barrier comprises a separation between the thermally sensitive portion and the thermally insensitive portion spanned by the lead.

16. The implantable device of claim 14, wherein the thermally insensitive portion comprises the one or more electrodes.

17. The implantable device of claim 13, wherein the thermally insensitive portion comprises a flapped appendage that is mechanically joined to the thermally insensitive portion at the thermal barrier.

18. The implantable device of claim 17, wherein the thermal barrier has a smaller area than an area of barriers that isolate the thermally insensitive portion from the body.

19. The implantable device of claim 13, wherein the thermally insensitive portion comprises the one or more electrodes.

20. The implantable device of claim 13, wherein the charging component comprises a coil configured to respond to an electric or a magnetic field generated outside the body.

21. An implantable device comprising:

a microstimulator dimensioned to be implanted in a body through a cannula of a surgical tool for performing closed surgical procedures, the microstimulator being configured to deliver electrical pulses to tissue of a body in which the microstimulator is implanted over one or more electrodes, the microstimulator comprising

a charging coil configured to convert an electric field or a magnetic field generated outside the body into potential energy, wherein the conversion is accompanied by a change in temperature,

electrical circuitry to manage delivery of the electrical pulses to the tissue of the body, and

a thermal barrier between the charging coil and the electrical circuitry, wherein the thermal barrier thermally isolates the charging coil from the electrical circuitry so that thermal resistance between the charging coil and the electrical circuitry is above the thermal resistance between the charging coil and the body.