Spinal cord stimulation with interferential current

• US 20040167584A1
• Filed: 01/22/2004
• Published: 08/26/2004
• Est. Priority Date: 01/22/2003
• Status: Active Grant

• Current Assignee: Meagan Medical, Inc.
• Original Assignee: Meagan Medical, Inc.
• Inventors: Carroll, William J., Terrell, Richard M.
• Granted Patent: US 8,977,363 B2
• Time in Patent Office: Days
• US Class Current: 607/46
• CPC Class Codes: A61N 1/0551 Spinal or peripheral nerve electrodes
• CPC Class Codes: A61N 1/0553 Paddle shaped electrodes, e.g. for laminotomy
• CPC Class Codes: A61N 1/36071 Pain
• CPC Class Codes: A61N 1/36171 Frequency
• CPC Class Codes: A61N 1/36175 Pulse width or duty cycle
• CPC Class Codes: A61N 1/36185 Selection of the electrode configuration
• CPC Class Codes: A61N 1/36192 Amplitude modulation
• CPC Class Codes: A61N 1/40 Applying electric fields by inductive or capacitive coupling microwave apparatus A61N5/00; Applying radio-frequency signals

Abstract

A stimulator and a method for the treatment of intractable pain syndromes by electrical stimulation of the spinal cord is disclosed in which implantable electrodes positioned around a targeted area of the spinal cord transmit an interferential current that has a base medium frequency alternating current between 500 Hz-20 KHz. A digital signal processor generates a sine-wave-like waveform from a pulse generator which after further processing is used to generate at least two circuits for use in producing the interferential current. An effective area of stimulation is controlled by the quantity of electrodes, positioning of the electrodes and electrode cross pattern orientation. Amplitude modulation of electrical circuits created at the electrode placements also augments the effective area of stimulation. The stimulator and method reduce accommodation of the body to the electrical stimulation and provide deeper penetration of the resultant signal.

Claims

1. An electrical stimulator for the treatment of intractable pain syndromes, comprising:

an interferential current generator for generating an interferential alternating current output by using common sine wave generators with a base medium frequency of at least 500 Hz but no more than 20 KHz; and

at least two pairs of implantable electrodes connected to said interferential current producing generator and located at predetermined locations on a subject'"'"'s spinal cord wherein each pair of implantable electrodes produces a separate electrical circuit.

2. The stimulator of claim 1, wherein said interferential current generator comprises:

a pulse generator that generates digital signal pulses; and

a digital signal processor connected to said pulse generator that processes the digital signal pulses to approximate a sine-wave-like output waveform.

3. The stimulator of claim 1, wherein said interferential current generator comprises:

a pulse generator that generates digital signal pulses; and

a field-programmable gate array connected to said pulse generator that processes the digital signal pulses to approximate a sine-wave-like output waveform.

4. The stimulator of claim 1, wherein said interferential current includes a resultant beat frequency of no more than 250 Hz.

5. The stimulator of claim 1, wherein said interferential current includes a voltage output of 11 volts maximum for each circuit.

6. The stimulator of claim 1, wherein said interferential current includes a pulse width of 210 microseconds.

7. The stimulator of claim 1, wherein said interferential current includes a pulse width with a range of at least 10 microseconds but no more than 600 microseconds.

8. The stimulator of claim 1, wherein two quadripolar leads are used to produce two interferential currents.

9. An electrical stimulator for the treatment of intractable pain syndromes, comprising:

a pulse generator that generates digital signal pulses;

a digital signal processor connected to said pulse generator that generates a sine-wave-like output waveform that is further processed into first and second circuits; and

two pairs of implantable electrodes connected to said digital signal processor and positioned on a subject'"'"'s spinal cord at predetermined locations to produce an interferential current output waveform from said first and second circuits.

10. The stimulator of claim 9, wherein said interferential current output waveform includes a base medium frequency of at least 500 Hz but no more than 20 KHz.

11. The stimulator of claim 9, wherein said interferential current output waveform includes a resultant beat frequency of no more than 250 Hz.

12. An electrical stimulator for the treatment of intractable pain syndromes, comprising:

a pulse generator that generates digital signal pulses;

a field-programmable gate array connected to said pulse generator that generates a sine-wave-like output waveform that is further processed into first and second circuits; and

two pairs of implantable electrodes connected to said field-programmable gate array and positioned on a subject'"'"'s spinal cord at predetermined locations to produce an interferential current output waveform from said first and second circuits.

13. The stimulator of claim 12, wherein said interferential current output waveform includes a base medium frequency of at least 500 Hz but no more than 20 KHz.

14. The stimulator of claim 12, wherein said interferential current waveform includes a resultant beat frequency of no more than 250 Hz.

15. An electrical stimulator for the treatment of intractable pain syndromes, comprising:

an interferential current generator for generating an interferential alternating current output with a base medium frequency of at least 500 Hz but no more than 20 KHz; and

at least two pairs of implantable electrodes connected to said interferential current producing generator and located at predetermined locations on a subject'"'"'s dorsal column wherein each pair of implantable electrodes produces a separate electrical circuit.

16. The stimulator of claim 15, wherein said interferential current generator comprises:

a pulse generator that generates digital signal pulses; and

a digital signal processor connected to said pulse generator that processes the digital signal pulses to approximate a sine-wave-like output waveform.

17. The stimulator of claim 15, wherein said interferential current generator comprises:

a pulse generator that generates digital signal pulses; and

a field-programmable gate array connected to said pulse generator that processes the digital signal pulses to approximate a sine-wave-like output waveform.

18. The stimulator of claim 15, wherein said interferential current includes a resultant beat frequency of no more than 250 Hz.

19. The stimulator of claim 15, wherein said interferential current includes a voltage output of 11 volts maximum for each circuit.

20. The stimulator of claim 15, wherein said interferential current includes a pulse width of 210 microseconds.

21. The stimulator of claim 15, wherein said interferential current includes a pulse width with a range of at least 10 microseconds but no more than 600 microseconds.

22. The stimulator of claim 15, wherein two quadripolar leads are used to produce two interferential currents.

23. An electrical stimulator for the treatment of intractable pain syndromes, comprising:

a pulse generator that generates digital signal pulses;

a digital signal processor connected to said pulse generator that generates a sine-wave-like output waveform that is further processed into first and second circuits; and

two pairs of implantable electrodes connected to said digital signal processor and positioned on a subject'"'"'s dorsal column at predetermined locations to produce an interferential current output waveform from said first and second circuits.

24. The stimulator of claim 23, wherein said interferential current output waveform includes a base medium frequency of at least 500 Hz but no more than 20 KHz.

25. The stimulator of claim 23, wherein said interferential current output waveform includes a resultant beat frequency of no more than 250 Hz.

26. An electrical stimulator for the treatment of intractable pain syndromes, comprising:

a pulse generator that generates digital signal pulses;

a field-programmable gate array connected to said pulse generator that generates a sine-wave-like output waveform that is further processed into first and second circuits; and

two pairs of implantable electrodes connected to said field-programmable gate array and positioned on a subject'"'"'s dorsal column at predetermined locations to produce an interferential current output waveform from said first and second circuits.

27. The stimulator of claim 26, wherein said interferential current output waveform includes a base medium frequency of at least 500 Hz but no more than 20 KHz.

28. The stimulator of claim 26, wherein said interferential current waveform includes a resultant beat frequency of no more than 250 Hz.

29. A method for the treatment of persistent chronic pain syndromes using electrical stimulation of the spinal cord, said method comprising:

connecting a pulse generator to a digital signal processor and supplying digital signal pulses to said digital signal processor which produces a sine-wave-like current waveform which is further processed and output to first and second pairs of implantable electrodes, wherein first and second circuits are created, respectively;

positioning said first pair of implantable electrodes on a subject'"'"'s spinal cord at one set of diagonal corners of a targeted area;

positioning said second pair of implantable electrodes on the subject'"'"'s spinal cord at the other set of diagonal corners of the targeted area; and

creating an interferential current with a base medium frequency of at least 500 Hz but no more than 20 KHz.

30. The method according to claim 29, wherein said method further includes varying locations of said first and second pairs of implantable electrodes along the spinal cord.

31. The method according to claim 29, wherein said method further includes modulating outputs of amplitudes of said first and second circuits.

32. The method according to claim 29, wherein said method includes creating an interferential current with a resultant beat frequency of no more than 250 Hz.

33. The method according to claim 29, wherein said method includes creating the interferential current with a voltage output of 11 volts maximum for each circuit.

34. The method according to claim 29, wherein said method includes creating the interferential current with a pulse width of 210 microseconds.

35. The method according to claim 29, wherein said method includes creating the interferential current with a pulse width comprising a range of at least 10 microseconds but no more than 600 microseconds.

36. The method according to claim 29, wherein said method includes creating two interferential currents by using two quadripolar leads.

37. A method for electrical stimulation of the spinal cord, said method comprising:

connecting a pulse generator to a digital signal processor and supplying digital signal pulses to said field-programmable gate array which produces a sine-wave-like current waveform which is further processed and output to first and second pairs ofimplantable electrodes, wherein first and second circuits are created, respectively;

positioning said first pair of implantable electrodes on a subject'"'"'s dorsal column at one set of diagonal corners of a targeted area;

positioning said second pair of surface electrodes on the subject'"'"'s dorsal column at the other set of diagonal corners of the targeted area; and

creating an interferential current with a base medium frequency of at least 500 Hz but no more than 20 KHz.

38. The method according to claim 37, wherein said method further includes varying positions of said first and second pairs of implantable electrodes along the dorsal column.

39. The method according to claim 37, wherein said method further includes modulating outputs of amplitudes of said first and second circuits.

40. The method according to claim 37, wherein said method includes creating an interferential current with a resultant beat frequency of no more than 250 Hz.

41. The method according to claim 37, wherein said method includes creating an interferential current with a pulse width of 210 microseconds.

42. The method according to claim 37, wherein said method includes creating two interferential currents by using two quadripolar leads.