INDUCTIVELY RECHARGEABLE IMPLANTABLE DEVICE WITH REDUCED EDDY CURRENTS

• US 20120274271A1
• Filed: 04/29/2011
• Published: 11/01/2012
• Est. Priority Date: 04/29/2011
• Status: Active Grant

• Current Assignee: LivaNova USA, Inc. (LivaNova Plc)
• Original Assignee: Cyberonics, Inc
• Inventors: Thompson, David L., Cowley, Anthony W., Hussain, Saadat, Flesher, James L., Shen, Jianxiang, Chow, Eric Y., Floyd, Jared B.
• Granted Patent: US 9,531,195 B2
• Time in Patent Office: Days
• US Class Current: 320/108
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/4029 for evaluating the peripheral nervous systems A61B5/24 takes precedence
• CPC Class Codes: A61B 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: H02J 2310/23 The load being a medical device, a medical implant, or a life supporting device
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/007182 in response to battery voltage

Abstract

A case for an implantable medical device includes a metal case portion, having an inside and an outside, configured to attach to at least one other case portion to define a biocompatible case for the implantable medical device. The metal case portion has a plurality of grooves disposed on at least one of the inside and the outside, the grooves being oriented substantially perpendicular to an expected direction of eddy currents produced by an inductive recharging coil in proximity thereto.

Claims

1. An implantable device, comprising:

an inductive recharging coil, coupled to a rechargeable battery and control circuitry, adapted to provide recharging current to the rechargeable battery in response to a proximate electromagnetic field; and

a conductive case, adapted for subcutaneous implantation, encasing the rechargeable battery, the control circuitry and the inductive recharging coil, having at least one of an inner surface and an outer surface with a pattern of grooves disposed thereupon, the grooves being oriented substantially normal to an anticipated direction of eddy current flow in response to the proximate electromagnetic field.

2. A device in accordance with claim 1, wherein at least one of a width and a depth of at least one groove of the pattern of grooves is non-uniform.

3. A device in accordance with claim 1, wherein the grooves are arranged in a substantially radial pattern.

4. A device in accordance with claim 3, wherein the radial pattern is substantially cross-shaped.

5. A device in accordance with claim 3, wherein the radial pattern is centered at an approximate center of expected eddy current generation.

6. A device in accordance with claim 1, wherein the grooves have a width of about 1 to 2 mm, and a groove depth of about 0.15 mm.

7. A device in accordance with claim 1, wherein the grooves extend entirely through the conductive case, and further comprising a dielectric material disposed on the grooves.

8. A device in accordance with claim 1, wherein the conductive case comprises a front side, and the grooves are disposed on at least one of the inner surface and the outer surface of the front side.

9. A device in accordance with claim 1, further comprising a polymer insert, attached to the inner surface of the conductive case, having a front surface shaped to nest in the grooves.

10. A device in accordance with claim 1, wherein the conductive case has a minimum cross-sectional thickness that is less than about 0.5 mm.

11. A device in accordance with claim 1, wherein the conductive case includes at least one of an interior surface and an exterior surface having a roughened texture.

12. A case for an implantable medical device, comprising a metal case portion, having an inside and an outside, configured to attach to at least one other case portion to define a biocompatible case for the implantable medical device, the metal case portion having a plurality of grooves disposed on at least one of the inside and the outside, the grooves being oriented substantially perpendicular to an expected direction of eddy currents produced by an inductive recharging coil in proximity thereto.

13. A case for an implantable medical device in accordance with claim 12, wherein the grooves define a substantially radial pattern, centered upon an expected center of eddy current generation.

14. A case for an implantable medical device in accordance with claim 12, wherein the grooves extend entirely through the metal case portion, and further comprising a dielectric material disposed on the grooves.

15. A case for an implantable medical device in accordance with claim 12, wherein the metal case portion is of titanium or titanium alloy, having a minimum thickness that is less than about 0.5 mm.

16. A rechargeable, implantable system, comprising:

an external recharging device, having a first inductive recharging coil; and

an implantable device having

a rechargeable battery;

a second inductive recharging coil, coupled to the rechargeable battery, and configured to provide recharging current to the rechargeable battery in response to a proximate electromagnetic field of the first recharging coil; and

a metal case housing the rechargeable battery and the second inductive recharging coil, the metal case having a front face disposed between the first and second inductive recharging coils, the front face having a plurality of grooves disposed on at least one of an inside and an outside of the front face, the grooves being oriented substantially perpendicular to an expected direction of eddy currents produced by operational proximity of the first and second inductive recharging coils.

17. A device in accordance with claim 16, wherein the grooves define a substantially radial pattern, centered upon an expected center of eddy current generation.

18. A system in accordance with claim 16, wherein the plurality of grooves extend through the front face of the metal case, and further comprising a dielectric material disposed on the grooves.

19. A system in accordance with claim 16, wherein the metal case is of titanium and has a minimum thickness of less than about 0.5 mm.

20. A system in accordance with claim 16, further comprising a roughened surface on at least one of an exterior surface and an interior surface of the front face.