NEURAL STIMULATION DEVICES AND SYSTEMS FOR TREATMENT OF CHRONIC INFLAMMATION

• US 20110190849A1
• Filed: 12/23/2010
• Published: 08/04/2011
• Est. Priority Date: 12/23/2009
• Status: Active Grant

• Current Assignee: Setpoint Medical Corporation
• Original Assignee: Setpoint Medical Corporation
• Inventors: Liu, Yiming, Simon, Jesse M., Faltys, Michael A.
• Granted Patent: US 8,612,002 B2
• Time in Patent Office: Days
• US Class Current: 607/50
• CPC Class Codes: A61N 1/0556 Cuff electrodes
• CPC Class Codes: A61N 1/36053 adapted for vagal stimulation A61N1/36114 takes precedence
• CPC Class Codes: A61N 1/3606 adapted for a particular treatment
• CPC Class Codes: A61N 1/36125 Details of circuitry or electric components
• CPC Class Codes: A61N 1/36142 for improving safety
• CPC Class Codes: A61N 1/36175 Pulse width or duty cycle
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/37235 Aspects of the external programmer
• CPC Class Codes: A61N 1/375 Constructional arrangements, e.g. casings
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators
• CPC Class Codes: A61N 1/3787 from an external energy source

Abstract

A system for treating chronic inflammation may include an implantable microstimulator, a wearable charger, and optionally an external controller. The implantable microstimulator may be implemented as a leadless neurostimulator implantable in communication with a cervical region of a vagus nerve. The microstimulator can address several types of stimulation including regular dose delivery. The wearable charger may be worn around the subject'"'"'s neck to rapidly (<10 minutes per week) charge an implanted microstimulator. The external controller may be configured as a prescription pad that controls the dosing and activity of the microstimulator.

Claims

1. A system for treating chronic inflammation in a patient, the system comprising:

an implantable microstimulator configured for implantation around a cervical portion of a vagus nerve to modulate inflammation by applying a low duty-cycle stimulation;

a charger configured to be worn around the patient'"'"'s neck and to charge the implantable microstimulator; and

an external controller configured to set a dose amplitude and dose interval for the microstimulator.

2. The system of claim 1, further comprising a POD for securing the microstimulator within the patient.

3. The system of claim 1, wherein the system is configured to charge the implantable microstimulator for less than about 10 minutes per week.

4. The system of claim 1, wherein the charger comprises a belt-like loop that fastens around the patient'"'"'s neck so that power may be transmitted by the loop to the implant.

5. The system of claim 1, wherein the external controller comprises an electronic prescription pad.

6. The system of claim 1, wherein the implantable microstimulator comprises a hermetically sealed capsule body having at least two conductive regions, the capsule body surrounding a resonator, battery and an electronic assembly sealed within the capsule body, wherein the electronic assembly is connected to the capsule body by a suspension configured to absorb mechanical shock.

7. The system of claim 6, wherein the electronic assembly comprises power management circuitry configured to receive power from the resonator to charge the battery, and a microcontroller configured to control stimulation of the vagus nerve from the conductive regions of the capsule body.

8. A system for treating chronic inflammation in a patient, the system comprising:

an implantable microstimulator configured for implantation around a cervical portion of a vagus nerve to modulate inflammation by applying low duty-cycle stimulation to the vagus nerve;

a POD configured to hold the implantable microstimulator in contact with a patient'"'"'s vagus nerve;

a charger configured to be worn around the patient'"'"'s neck and to charge the implantable microstimulator implanted within the patient'"'"'s neck region; and

an external controller configured to communicate with the microstimulator through the charger and to thereby set the dose amplitude and dose interval for the microstimulator,

wherein microstimulator is configured to continuously modulate inflammation while charging by the charger for less than 10 minutes per week.

9. The system of claim 8, wherein the system is configured to charge the implantable microstimulator for less than about 10 minutes per day.

10. The system of claim 8, wherein the charger comprises a belt-like loop that fastens around the patient'"'"'s neck so that power may be transmitted by the loop to the implant.

11. The system of claim 8, wherein the charger loop is magnetically fastened for quick release and electrical contact is made through one or more spring like contacts for each turn of the coil.

12. The system of claim 8, wherein the external controller comprises an electronic prescription pad.

13. The system of claim 8, wherein the implantable microstimulator comprises a hermetically sealed capsule body having at least two conductive regions, the capsule body surrounding a resonator, battery and an electronic assembly sealed within the capsule body, wherein the electronic assembly is connected to the capsule body by a suspension configured to absorb mechanical shock.

14. The system of claim 12, wherein the electronic assembly comprises power management circuitry configured to receive power from the resonator to charge the battery, and a microcontroller configured to control stimulation of the vagus nerve from the conductive regions of the capsule body.

15. A leadless, implantable microstimulator device for treating chronic inflammation, the device comprising:

a hermetically sealed capsule body;

at least two electrically conductive capsule regions, wherein each region electrically connects to an electrode for applying stimulation to a vagus nerve;

a resonator within the sealed capsule body;

a battery within the sealed capsule body; and

an electronic assembly within the sealed capsule body, wherein the electronic assembly is connected to the capsule body by a suspension configured to absorb mechanical shock and make electrical contact;

wherein the electronic assembly comprises power management circuitry configured to receive power from the resonator to charge the battery, and a microcontroller configured to control stimulation of the vagus nerve from the conductive capsule regions.

16. The device of claim 15 wherein the capsule body comprises a ceramic body with hermetically sealed titanium alloy ends and integral platinum-iridium electrodes attached thereto.

17. The device of claim 15, further comprising an overtemperature control including a thermistor that is configured to shut the device down if the operating temperature exceeds a 41°

C.

18. The device of claim 15, wherein the battery comprises a Lithium solid-state battery.

19. The device of claim 15, further comprising voltage limiters to limit the amount of power that can charge the battery from the resonator.

20. The device of claim 15, further comprising load stabilizers to reduce communication errors due to power load fluctuations.

21. The device of claim 15, wherein the at least two electrically conductive capsule regions comprise the ends of the capsule body.

22. The device of claim 15, wherein the at least two electrically conductive capsule regions are made from a resistive titanium alloy to reduce magnetic afield absorption.

23. The device of claim 15, wherein the suspension comprises clips or springs.

24. The device of claim 15, further comprising an H-bridge current source with capacitor isolation connecting each of the two electrically conductive capsule regions.

25. The device of claim 15, further comprising a temperature sensor configured to detune the resonator to prevent energy absorption if the temperature exceeds a predetermined value.

26. The device of claim 15, further comprising an overvoltage sensor configured to detune the resonator to prevent energy absorption.

27. The device of claim 15, further comprising a current limiter configured to limit current from the resonator to enable reliable powerup.

28. The device of claim 15, wherein the resonator comprises a coil and capacitor configured to resonate at about 131 KHz+/−

2%.

29. The device of claim 15, wherein the resonator comprises a ferrite coil wherein the ferromagnetic material is chosen to maximize permittivity in the operating range and minimize permittivity and energy absorption from higher frequency sources such as MRI and Diathermy devices.

30. The device of claim 15, wherein the electronic assembly comprises telemetry circuitry configured to detect and demodulate control information from the resonator and communicate the control information with the microcontroller.

31. A leadless, implantable microstimulator device for treating chronic inflammation by stimulation of a cervical region of a vagus nerve, the device comprising:

a hermetically sealed capsule body having two electrically conductive capsule end regions separated by a central non-conductive region, wherein each conductive region is configured to electrically connect to an electrode for applying stimulation to a vagus nerve;

a resonator, battery and electronic assembly within the sealed capsule body; and

a suspension connecting the electronic assembly to the capsule body to absorb mechanical shock;

wherein the electronic assembly comprises power management circuitry configured to receive power from the resonator to charge the battery, and a microcontroller configured to control stimulation of the vagus nerve from the conductive capsule regions.

32. A charger device configured to be worn around a patient'"'"'s neck for charging a microstimulator implanted in the patient'"'"'s neck, the device comprising:

an energizer coil configured to fit around the patient'"'"'s neck;

a latch configured to releasably secure together two ends of the energizer coil to close the energizer coil and form a solenoid loop around the patient'"'"'s neck; and

a class-D amplifier driving the solenoid loop and configured to create a magnetic field of between about 40 and 100 A/m at a frequency of between about 120 and 140 KHz.

33. The device of claim 32, wherein the latch comprises a plurality of pins making electrical connection between the ends of the energizer coil, the pins configured to maintain a low coil resistance and high Q.

34. The device of claim 32, wherein the class-D) amplifier comprises a high efficiency class-D amplifier.

35. The device of claim 32, wherein the class-D amplifier is configured to be driven at a variable frequency to maximize power transfer.

36. The device of claim 32, wherein the class-D amplifier output is driven to optimize the microstimulator power absorption by measuring the back-telemetry modulation depth.

37. The device of claim 32, wherein the class-D amplifier controls temperature and prevents telemetry channel saturation.

38. The device of claim 32, further comprising a digitally compensated pwm circuit to modulate the magnetic field strength and tune the power.

39. The device of claim 32, wherein the class-D amplifier driving the solenoid loop is configured to create a magnetic field of between about 47-94 A/m at a frequency of between about 127-135 KHz.

40. The device of claim 32, further comprising resonators that are adjustable to between about 127 KHz to 135 KHz.

41. The device of claim 32, further comprising a telemetry system.

42. The device of claim 41, wherein the telemetry system comprises a microprocessor configured to modulate a transmitter collector voltage to send data.

43. The device of claim 32, further comprising a display.

44. A charger device configured to be worn around a patient'"'"'s neck for charging a microstimulator implanted in the patient'"'"'s neck, the device comprising:

a solenoid loop configured to be worn around the patient'"'"'s neck; and

a class-D amplifier driving the solenoid loop and configured to create a magnetic field of between about 40 and 100 A/m at a frequency of between about 120 and 140 KHz.

45. A method of treating chronic inflammation in a patient, the method comprising:

implanting a microstimulator in the patient'"'"'s neck in electrical communication with a cervical region of the subject'"'"'s vagus nerve; and

charging and programming the implanted microstimulator from a charger worn around the subject'"'"'s neck.

46. The method of claim 45, further comprising applying electrical energy to the vagus nerve to modulate inflammation.

47. The method of claim 45, further comprising programming the microstimulator using an external controller and transmitting control information from the charger.

48. The method of claim 45, wherein the step of inserting the microstimulator comprises inserting the microstimulator into a Protection and Orientation device (POD) that at least partially surrounds the vagus nerve, wherein the POD is configured to secure the microstimulator in communication with the vagus nerve.

49. The method of claim 45, wherein the step of inserting the microstimulator comprises implanting a microstimulator having a hermetically sealed capsule body with at least two electrically conductive capsule regions separated by a non-conductive region and a resonator, battery and electronic assembly within the sealed capsule body, and a suspension connecting the electronic assembly to the capsule body to absorb mechanical shock.

50. The method of claim 45, further comprising securing a charging device around the patient'"'"'s neck.

51. The method of claim 45, further comprising securing a charging device around the patient'"'"'s neck by latching the charging device around the patient'"'"'s neck to form a complete solenoid loop.

52. The method of claim 45, wherein the step of charging and programming the implanted microstimulator comprises emitting a magnetic field of between about 40 and 100 A/m at a frequency of between about 120 and 140 KHz from the charger.

53. A method of treating chronic inflammation in a patient, the method comprising:

implanting a microstimulator in the patient'"'"'s neck in electrical communication with a cervical region of the subject'"'"'s vagus nerve;

stimulating the subject'"'"'s vagus nerve to modulate inflammation;

securing a charging device around the patient'"'"'s neck; and

charging the implanted microstimulator from a charger worn around the subject'"'"'s neck for less than 20 minutes per week by emitting a magnetic field of between about 40 and 100 A/m at a frequency of between about 120 and 140 KHz from the charger.