NEUROSTIMULATOR

• US 20110077722A1
• Filed: 10/20/2010
• Published: 03/31/2011
• Est. Priority Date: 08/19/2002
• Status: Active Grant

• Current Assignee: Arizona Board of Regents (University of Arizona)
• Original Assignee: Arizona Board of Regents (University of Arizona)
• Inventors: Crisp, William E., Towe, Bruce
• Granted Patent: US 8,626,303 B2
• Time in Patent Office: Days
• US Class Current: 607/68
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/32 alternating or intermittent currents applying electric fields by inductive or capacitive coupling A61N1/40; microwave apparatus A61N5/02
• CPC Class Codes: A61N 1/36071 Pain
• CPC Class Codes: A61N 1/36125 Details of circuitry or electric components
• 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: A61N 7/00 Ultrasound therapy lithotripsy A61B17/22, A61B17/225; massage using supersonic vibration A61H23/00 ; using ultrasound for introducing media into the body A61M37/0092

Abstract

Methods and devices of stimulating nerves are disclosed. In one embodiment adapted for stimulating excitable tissue, the invention includes drive circuitry (12), an acoustic transducer (14) and a pair of electrodes (28).

Claims

1. An isotropic implantable receiver-stimulator device comprising:

(a) an acoustic transducer assembly which receives acoustic energy from an acoustic source and converts the acoustic energy into electrical signals,

(b) demodulator circuitry connected to receive the electrical signals and convert said signals to a biologically stimulating electrical output; and

(c) at least two tissue contacting stimulation electrodes which receive the stimulating electrical output and deliver said output to tissue, wherein the electric output that is produced by the isotropic implantable receiver-stimulator is substantially insensitive to the relative orientation of the receiver-stimulator to the acoustic source, wherein the transducer assembly comprises a plurality of individual transducer elements and wherein the demodulator circuitry comprises a plurality of individual demodulator circuits, with the electrical signal from each transducer element going to a demodulator circuit which produces an output, further comprising summing circuitry which sums all of the converted electrical signals from all of the demodulator circuits to produce the biologically stimulating electrical output.

2. An implantable receiver-stimulator as in claim 1, wherein the electric signal produced by the transducer assembly in response to the acoustic energy varies by no more than ±

6 dB as the orientation relative to an acoustic source varies.

3. An implantable receiver-stimulator as in claim 1, wherein the electric signal produced by the transducer assembly in response to the acoustic energy varies by no more than ±

3 dB as the orientation relative to an acoustic source varies.

4. A device as in claim 1, wherein the transducer assembly comprises a piezoelectric transducer material.

5. A device as in claim 4, wherein piezoelectric transducer material is composed of a polycrystalline ceramic piezoelectric material or is composed of a single crystal piezoelectric material.

6. A device as in claim 4, wherein the transducer assembly comprises a plurality of cylindrical piezoelectric transducers having a pair of opposed surfaces, wherein the conductive transducer electrodes are formed over the opposed surfaces.

7. A device as in claim 6, wherein the conductive transducer electrodes are formed over outer and inner cylindrical surfaces.

8. A device as in claim 6, wherein the piezoelectric transducer is composed of a single crystal piezoelectric material that is cut in the <

001>

or <

011>

orientation.

9. A device as in claim 8, wherein the opposed electrodes are formed over flat end surfaces of the cylinder.

10. A device as in claim 4, wherein the transducer assembly comprises a transducer composed of a single crystal cut in the <

001>

or <

011>

orientation.

11. A device as in claim 1, wherein the transducer assembly comprises a plurality of transducers composed of a single crystal material of the PMN-xPT family, where x is in the range from 5% to 50%.

12. A device as in claim 1, wherein the transducer assembly comprises a transducer composed of a single crystal material of the PZN-xPT family, where x is in the range from 5% to 50%.

13. A device as in claim 1, wherein the transducer assembly comprises a transducer composed of a single crystal material of the Relaxor-PT family.

14. A device as in claim 5, wherein the acoustic source transmits the acoustic energy at a frequency selected to match the lower frequency resonance of the piezoelectric transducer material composed of the single crystal piezoelectric material.

15. A device as in claim 1, wherein the converted electrical signals are summed in parallel.

16. A device as in claim 1, wherein the converted electrical signals are summed in series.

17. A device as in claim 1, wherein the converted electrical signals are summed in a series-parallel combination.

18. A device as in claim 1, wherein the transducer elements each have a size less than one-half the wavelength of the acoustic source while collectively having a size greater than one wavelength in any lateral dimension.

19. A device as in claim 1, further comprising a shell having, a wall surrounding an interior volume, wherein the transducer assembly and demodulator circuitry are within the interior volume and wherein at least a portion of the wall is acoustically transmissive.

20. A device as in claim 19, wherein the entire shell is acoustically transmissive.

21. A device as in claim 20, wherein the shell is cylindrical.

22. A device as in claim 21, wherein the shell has a diameter less than 5.0 mm and a length less than 20.0 mm more preferably a diameter less than 3.0 mm and a length less than 10.0 mm.

23. A system comprising;

an isotropic implantable receiver-stimulator as in claim 1; and

an implantable acoustic controller-transmitter configured to transmit acoustic energy through tissue to the implantable receiver stimulator.

24. A receiver-stimulator device comprising:

a plurality of acoustic transducers, each comprising an implanted piezoelectric chip, that receive acoustic energy from an acoustic source and generate acoustic energy to generate an electric current;

a demodulator connected to each transducer receive the electrical signals and rectify the signals to a biologically stimulating electrical output; and

at least two tissue contacting stimulation electrodes coupled to each demodulator which receive the stimulating electrical output and deliver said output to tissue; and

wherein the contributions of the plurality of acoustic transducers are placed in series such the electric output of each transducer is additive.

25. The device of claim 24, wherein the plurality transducers are positioned such that a resulting transducer array is substantially symmetrical and annular.

26. The device of claim 24, wherein the electrodes are nerve cuff electrodes disposed around a nerve.

27. The device of claim 26, wherein the nerve cuff electrodes stimulate a specific nerve fiber.

28. The device of claim 26, wherein the transducers are ultrasound transducers of sub-millimeter size disposed around the circumference of the nerve cuff and each ultrasound transducer is electrically addressed.