IMPLANTABLE DEVICE WITH HEAT STORAGE

• US 20100256708A1
• Filed: 04/03/2009
• Published: 10/07/2010
• Est. Priority Date: 04/03/2009
• Status: Active Grant

• Current Assignee: ReShape LifeSciences, Inc.
• Original Assignee: EnteroMedics, Inc. (ReShape LifeSciences, Inc.)
• Inventors: Sprain, Jason W., Thornton, Arnold W., Weijand, Koen J., Donders, Adrianus P.
• Granted Patent: US 8,326,426 B2
• Time in Patent Office: Days
• US Class Current: 607/61
• CPC Class Codes: A61N 1/37229 Shape or location of the implanted or external antenna
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

Example embodiments of an implantable device are configured to be implanted within a patient to provide medical therapy to the patient. In general, an implantable rechargeable device includes a rechargeable battery and an electronic board assembly arranged within a case and an antenna electrically coupled to the rechargeable battery. The antenna is configured to receive power and to transfer at least a portion of the received power to the rechargeable battery for recharging. A phase change material is arranged within the case around at least a portion of the electronic board assembly. The phase change material is configured to transition from a first phase to a second phase at a transition temperature when the insulating material absorbs heat (e.g., from the electronic board assembly).

Claims

1. An implantable device comprising:

a case comprising defining a device enclosure, a thermal insulating material covering all or a portion of the case;

an electronic board assembly arranged within the device enclosure, the electronic board assembly being configured to generate therapy signals;

a rechargeable power source arranged operationally coupled to the electronic board assembly;

an antenna operationally coupled to the electronic board assembly, the antenna being configured to receive power and to transfer at least a portion of the received power to the electronic board assembly for distribution to the rechargeable power source for recharging; and

a phase change material arranged within the device enclosure around at least a portion of the electronic board assembly, the phase change material being selected to have a transition temperature, mass, and latent heat sufficient to inhibit a rise in temperature within the case from increasing a temperature at the implant-tissue interface by more than about 2°

C. (about 4°

F.) above a threshold temperature.

2. The device of claim 1, wherein the thermal insulating material is arranged along at least a portion of the interior of the case.

3. The device of claim 2, wherein the thermal insulating material has a thermal resistivity sufficient to insulate the exterior of the case from a temperature rise of more than 2°

C. when the temperature in the interior of the case rises at least 1°

C. to 10°

C.

4. The device of claim 3, wherein the thermal insulating material is selected from the group consisting of mylar, Teflon, silicone polymer, and nylon.

5. The device of claim 1, wherein the rechargeable power source is a battery.

6. The device of claim 5, wherein the battery has charge capacity of about 200 to 500 mAh.

7. The device of claim 5, wherein the battery is a lithium ion battery.

8. The device of claim 1, wherein the phase change material has a transition temperature of about 37°

C. to 80°

C.

9. The device of claim 8, wherein the phase change material includes paraffin wax.

10. The device of claim 9, wherein the phase change material includes paraffin wax absorbed into microstructures of expanded graphite.

11. The device of claim 1, wherein the phase change material absorbs heat output by the electronic board assembly when the antenna receives power to recharge the power source.

12. The device of claim 1, wherein the electronic board assembly includes a rectification circuit and wherein the phase change material absorbs heat output by the rectification circuit when the power source is recharged.

13. The device of claim 1, wherein the phase change material has a latent heat of absorption between 40 J/g. and 2260 J/g.

14. The device of claim 1, further comprising a temperature sensor arranged within the case and configured to measure a temperature within the case.

16. The device of claim 1, wherein the case can accommodate the phase change material when the phase change material expands or contracts when transitioning from the first state to the second state.

17. The device of claim 16, wherein the space provided within the case is under vacuum.

18. The device of claim 16, wherein the space provided within the case is at approximate atmospheric pressure and is filled with an inert gas.

19. The device of claim 16, wherein the space provided within the case is filled with a hydrochlorofluorocarbon (HCFC).

20. The device of claim 16, wherein the space provided within the case is filled with a chlorinated fluorocarbon (CFC).

21. The device of claim 16, wherein the space provided within the case is filled with perfluorocarbon.

22. The device of claim 16, wherein the space provided within the case is at approximate atmospheric pressure and is filled with a non-inert gas.

15. The device of claim 15, wherein the electronic board assembly stops recharging the power source when the temperature sensor determines the temperature within the case exceeds a predetermined threshold.

23. A method of manufacturing an implantable device comprising:

arranging a rechargeable battery and an electronic board assembly within a case, wherein the case comprises a thermal insulating material and wherein the rechargeable battery and the electronic board assembly are electrically coupled to each other, and wherein the electronic board assembly is active when generating therapy signals and when the rechargeable battery is being recharged;

electrically coupling an antenna to the rechargeable battery and the electronic board assembly; and

arranging a phase change material within the case in an amount sufficient to inhibit a rise in temperature at the implant-tissue interface by more than about 2°

C. when the electronic board assembly is active.

24. The method of claim 23, wherein arranging the phase change material includes pouring the phase change material over at least a portion of the electronic board assembly.

25. The method of claim 23, wherein arranging the phase change material includes pouring the phase change material over an entirety of the electronic board assembly.

26. The method of claim 23, wherein arranging the phase change material includes pouring the phase change material over at an entirety of the electronic board assembly and the power source.

27. The method of claim 23, further comprising reducing the pressure of the case subsequent to arranging the phase change material within the case.

28. The method of claim 23, further comprising backfilling the case with an inert gas subsequent to arranging the phase change material within the case.

29. The method of claim 28, further comprising backfilling the case with an organic material.

30. The method of claim 29, wherein the organic material is selected from the group consisting of perfluorocarbon, hydrochlorofluorocarbon (HCFC), and hydrochlorofluorocarbon (HCFC).

31. An implantable device comprising:

a case defining a device enclosure and comprising a thermal insulating material;

at least one heat-generating component arranged within the enclosure of the case;

an electronic board assembly arranged within the device enclosure, the electronic board assembly being configured to generate therapy signals; and

a phase change material arranged within the device enclosure around at least a portion of the heat-generating component, the phase change material being configured to absorb heat produced by the heat-generating component and to transition from a first state to a second state when sufficient heat is absorbed to increase a temperature of the phase change material to a transition temperature, wherein a mass of the phase change material is selected so as to inhibit a rise in temperature at the implant-tissue interface by more than about 2°

C. (about 4°

F.).

32. The implantable device of claim 31, wherein the heat-generating component includes a rectification circuit arranged on the electronic board assembly.

33. The implantable device of claim 31, wherein the heat-generating component includes a rechargeable power source arranged within the device enclosure.