Implantable neurostimulation systems

• US 20080004676A1
• Filed: 06/15/2007
• Published: 01/03/2008
• Est. Priority Date: 06/16/2006
• Status: Active Grant

• Current Assignee: Neuropoint Medical, Inc.
• Original Assignee: Neuropoint Medical, Inc.
• Inventors: Kim, Hyoung-Ihl, Osypka, Thomas, Shin, Yong-Il
• Granted Patent: US 8,116,875 B2
• Time in Patent Office: Days
• US Class Current: 607/59
• CPC Class Codes: A61N 1/0531 Brain cortex electrodes
• CPC Class Codes: A61N 1/0539 Anchoring of brain electrode systems, e.g. within burr hole

Abstract

The subject invention is directed to new and useful neurostimulation systems that include an implantable pulse generator dimensioned and configured for implantation in the skull of a patient. The implantable pulse generator has an electrode operatively associated with a distal end portion thereof and can be provided with adjustment means, such as an adjustable biasing member or spring arranged between the electrode to the distal end portion of the pulse generator. The subject invention is also directed to systems involving networked neurostimulators that are configured and adapted to work jointly in accordance with prescribed treatment protocol to effect a desired recovery from brain injury. Such networked neurostimulation systems are particularly advantageous for effecting relatively large and/or relatively distant regions of the brain. The subject invention is further directed to systems and methods for motor-evoked potential (MEP)-based neuromodulation. Further, AC and/or DC stimulation can be utilized, depending on the precise implementation.

Claims

1. An implantable neurostimulator comprising:

a) a housing;

b) mounting means for securing the housing and the neurostimulator to a cranium of a patient;

c) stimulus generating means provided within the housing for generating a therapeutic electrical stimulus;

d) a first electrode for contacting a dura of a brain of the patient;

e) an electrically conductive element operatively connecting the pulse generating means and the electrode, adapted and configured to deliver the electrical stimulus generated by the pulse generating means to the electrode; and

f) a stem element arranged between the housing and the electrode, a length of the stem setting a minimum distance between the housing and the electrode.

2. The implantable neurostimulator of claim 1, further comprising an antenna operatively connected to the pulse generating means, the pulse generating means receiving a control signal from an external control unit through the antenna.

3. The implantable neurostimulator of claim 1, further comprising biasing means arranged between the mounting means and the electrode for biasing the electrode toward the brain of the patient.

4. The implantable neurostimulator of claim 3, wherein the biasing means is arranged between the housing and the electrode.

5. The implantable neurostimulator of claim 3, wherein the biasing means is a resilient element.

6. The implantable neurostimulator of claim 5, wherein the biasing means is a spring.

7. The implantable neurostimulator of claim 5, wherein the biasing means functions as the electrically conductive element by having at least an electrically conductive portion.

8. The implantable neurostimulator of claim 3, wherein the biasing means is one or more shims.

9. The implantable neurostimulator of claim 1, wherein the mounting means is integrally formed with the housing.

10. The implantable neurostimulator of claim 9, wherein the mounting means is includes one or more extension portions extending from the housing, adapted and configured to be secured to the cranium of the patient by one or more mechanical fasteners.

11. The implantable neurostimulator of claim 1, wherein the mounting means is integrally formed with the stem element, the stem element directly engaging the cranium of the patient.

12. The implantable neurostimulator of claim 11, wherein the mounting means includes threads arranged on an outer surface of the stem element for engaging the cranium of the patient.

13. The implantable neurostimulator of claim 11, wherein the mounting means includes a textured surface arranged on an outer surface of the stem element for engaging the cranium of the patient.

14. The implantable neurostimulator of claim 13, wherein the textured surface is adapted and configured to promote bone ingrowth into the neurostimulator, to aid fastening of the neurostimulator to the cranium.

15. The implantable neurostimulator of claim 1, wherein the mounting means includes a fastening strap adapted and configured to engage the housing and to be secured to the cranium of the patient by one or more mechanical fasteners.

16. The implantable neurostimulator of claim 1, wherein the mounting means includes a platform element configured and adapted to be secured to the cranium of the patient by one or more mechanical fasteners, to which the stem element is also mutually engageable.

17. The implantable neurostimulator of claim 1, wherein the stem element functions as the electrically conductive element by having at least an electrically conductive portion.

18. The implantable neurostimulator of claim 1, wherein the housing includes a cap portion and a base portion sealed together, forming the housing.

19. The implantable neurostimulator of claim 1, further comprising a retainer lip arranged on a lower surface of the housing, adapted and configured to engage the stem element.

20. The implantable neurostimulator of claim 19, wherein the retainer lip includes an anti-rotation feature to inhibit relative rotation between the retainer lip and the stem element.

21. The implantable neurostimulator of claim 1, wherein the housing is adapted and configured to function as a second electrode, to complete an electrical circuit with the first electrode when delivering a therapeutic electrical stimulus.

22. The implantable neurostimulator of claim 1, wherein the housing is provided with a separate second electrode, carried thereon, to complete an electrical circuit with the first electrode when delivering a therapeutic electrical stimulus.

23. The implantable neurostimulator of claim 1, wherein the first electrode is adapted and configured to slideably engage the stem element, a biasing element being provided between the electrode and stem element for urging the first electrode toward the brain of the patient.

24. The implantable neurostimulator of claim 23, wherein the stem element is provided with a groove for engaging the biasing element, to prevent unintentional relative translation between the stem element and the biasing element.

25. The implantable neurostimulator of claim 1, further comprising an aperture defined in the housing, configured and adapted to receive passage of an antenna, extending from the stimulus generating means outside of the housing.

26. The implantable neurostimulator of claim 25, wherein a feedthrough element is provided within the aperture to seal an internal environment of the housing from the external environment of the housing.

27. The implantable neurostimulator of claim 1, further comprising an aperture defined in the housing, configured and adapted to receive passage of a conductor, extending from the stimulus generating means to the first electrode.

28. A system for therapeutic neurostimulation, the system comprising:

a) a plurality of implantable neurostimulators in accordance with claim 1;

and

b) communication means connecting the plurality of neurostimulators.

29. The system for therapeutic neurostimulation of claim 28, wherein the plurality of implantable neurostimulators are arranged in an array in the cranium of the patient.

30. The system for therapeutic neurostimulation of claim 29, wherein the array is a rectangular array.

31. The system for therapeutic neurostimulation of claim 18, wherein the array is a circular array.

32. The system for therapeutic neurostimulation of claim 28, wherein the plurality of implantable neurostimulators are adapted and configured to communicate with one another by way of a conductive element provided between implantable neurostimulators.

33. The system for therapeutic neurostimulation of claim 28, wherein the plurality of implantable neurostimulators are adapted and configured to communicate with one another by way of a wireless signal.

34. The system for therapeutic neurostimulation of claim 28, wherein at least one implantable neurostimulator is adapted and configured to receive power from at least one other implantable neurostimulator by way of a conductive element provided between implantable neurostimulators.

35. The system for therapeutic neurostimulation of claim 28, further comprising a programmer provided external to the patient for programming a predetermined treatment protocol into at least one of the implantable neurostimulators.

36. A method for using motor evoked potential (MEP) for determination of optimal treatment parameters, the method including the steps of:

a) implanting a primary stimulating electrode in a target region of the brain cortex, in which treatment is desired;

b) implanting a satellite stimulating electrode arranged on the motor cortex of the patient'"'"'s brain;

c) stimulating the motor cortex a first time by way of the satellite stimulating electrode and measuring a motor evoked potential (MEP) at a muscle corresponding to the stimulated region of the motor cortex;

d) stimulating the target region of the brain by way of the primary stimulating electrode;

e) stimulating the motor cortex a second time by way of the satellite stimulating electrode and measurement of motor evoked potential (MEP) at the muscle corresponding to the stimulated region of the motor cortex;

f) comparing the cortical excitability between the first motor cortex stimulation and the second motor cortex stimulation;

g) determining optimal treatment parameters based on the compared cortical excitability; and

h) stimulating the target region by way of the primary stimulating electrode for a treatment duration.

37. The method of claim 36, further comprising repeating of step c through step g during or after a prescribed course of treatment.