THERMAL STIMULATION PROBE AND METHOD

• US 20120095535A1
• Filed: 12/26/2011
• Published: 04/19/2012
• Est. Priority Date: 05/22/2003
• Status: Active Grant

• Current Assignee: Medoc Ltd.
• Original Assignee: Medoc Ltd.
• Inventors: Gafni, Ehud, Granovsky, Yelena
• Granted Patent: US 8,652,189 B2
• Time in Patent Office: Days
• US Class Current: 607/96
• CPC Class Codes: A61B 5/377 using evoked responses
• CPC Class Codes: A61B 5/383 Somatosensory stimuli, e.g. electric stimulation
• CPC Class Codes: A61B 5/4821 Determining level or depth of anaesthesia A61B5/1106 takes precedence
• CPC Class Codes: A61F 2007/0001 Body part
• CPC Class Codes: A61F 2007/0071 using a resistor, e.g. near the spot to be heated
• CPC Class Codes: A61F 2007/0075 using a Peltier element, e.g. near the spot to be heated or cooled
• CPC Class Codes: A61F 2007/0076 remote from the spot to be heated or cooled
• CPC Class Codes: A61F 7/007 characterised by electric heating

Abstract

A physiological thermal stimulation probe, comprising:

• • (a) an electrically controlled heat control element with a relatively low thermal capacity and adapted for contact with tissue on one side thereof;
  • (b) a thermal sink/source with a relatively high effective thermal capacity and a relatively low thermal impedance, such that said thermal sink/source sink can rapidly change a temperature of said heat control element, at a rate above 10 degrees Celsius per second, from a temperature of below 100 degrees Celsius; and
  • (c) circuitry which activates said heat control element to achieve a desired temperature stimulation profile of said tissue.

Claims

1. A physiological thermal stimulation probe, comprising:

(a) an electrically controlled heat control element including a part having a relatively low thermal capacity and adapted for contact with tissue on one side thereof;

(b) a thermal sink/source with a relatively high effective thermal capacity and a relatively low thermal impedance, said thermal sink/source being thermally coupled to said side adapted for contact with tissue and said thermal sink/source having a thermal capacity of at least four times a thermal capacity of said part of said electrically controlled heat control element; and

(c) circuitry which activates said heat control element to achieve a desired temperature stimulation profile of said tissue,

wherein said coupling of said thermal sink/source to said side adapted for contact with tissue is sufficient so that heat flow between the control element and the sink/source can change a temperature of said side adapted for contact with tissue at a rate above 10 degrees Celsius per second.

2. A physiological thermal stimulation probe according to claim 1, wherein said heat control element functions as a cooling element and wherein said thermal sink/source functions as a heat source.

3. A physiological thermal stimulation probe according to claim 1, wherein said heat control element functions as a heating element and wherein said thermal sink/source functions as a heat sink.

4. A probe according to claim 3, wherein said heat sink comprises a cold thermal mass.

5. A probe according to claim 4, wherein said cold thermal mass comprises a thermally conducting plate.

6. A probe according to claim 3, wherein said heat sink comprises an active cooling element.

7. A probe according to claim 4, wherein said heat sink comprises an active cooling thermally coupled to said thermal mass.

8. A probe according to claim 6, said cooling element comprises a Peltier element.

9. A probe according to claim 6, wherein said cooling element comprises a heat pump.

10. A probe according to claim 7, comprising at least one temperature sensor in association with said thermal mass, wherein said circuitry applies closed loop feedback to control a temperature of said thermal mass cooling element using said temperature sensor to control an activation of said active cooling element.

11. A probe according to any of claims 3-10, comprising at least one temperature sensor in association with said heating element, wherein said circuitry applies closed loop feedback to control a temperature of said heating element using said temperature sensor to control an activation of said heating element.

12. A probe according to claim 10 or claim 11, wherein said circuitry samples said at least one temperature sensor at faster than 10 Hz.

13. A probe according to claim 10 or claim 11, wherein said circuitry samples said at least one temperature sensor at faster than 50 Hz.

14. A probe according to any of claims 3-13, wherein said circuitry controls said probe to provide a pulse of heat.

15. A probe according to any of claims 3-14, wherein said circuitry controls said probe to provide a pulse of cold.

16. A probe according to any of claims 3-15, wherein said circuitry controls said probe to selectively stimulate A-delta fibers.

17. A probe according to any of claims 3-16, wherein said circuitry controls said probe to selectively stimulate a subgroup of A-delta fibers.

18. A probe according to claim 17, wherein said sub-group comprises cold sensing fibers.

19. A probe according to claim 17, wherein said sub-group comprises either high or low threshold fibers.

20. A probe according to any of claims 3-19, wherein said circuitry controls said probe to selectively stimulate C fibers.

21. A probe according to any of claims 3-19, wherein said circuitry controls said probe to generate a windup effect.

22. A probe according to any of claims 3-19, wherein said circuitry controls said probe to provide a second pain effect.

23. A probe according to any of claims 3-22, wherein said circuitry controls said probe to have a temperate raise rate of over 30 degrees Celsius per second.

24. A probe according to any of claims 3-23, wherein said circuitry controls said probe to have a temperate decrease rate of over 30 degrees Celsius per second.

25. A probe according to any of claims 3-24, wherein said heating element comprises an array of individually controllable heating elements.

26. A probe according to any of claims 3-24, wherein said heating element comprises a foil heater.

27. A probe according to any of claims 3-26, wherein said circuitry includes a trigger input for triggering stimulation.

28. A probe according to any of claims 3-27, wherein said circuitry includes a trigger output for generating an external trigger.

29. A probe according to any of claims 3-28, wherein said circuitry maintains said probe at a neutral temperature by providing an activation of said heating element to offset the effect of said heat sink.

30. A probe according to any of claims 3-29, wherein said circuitry pre-cools said heat sink.

31. A probe according to any of claims 1-30, including means for sensing brain activity.

32. A probe according to claim 31, including circuitry adapted to display a degree of pain blocking.

33. A probe according to claim 31, including circuitry adapted to display a consciousness level.

44. A probe according to any of claims 1-33, wherein said circuitry is configured to control said heat control elements to produce sharp temperature spikes including a sharp leading edge, a short duration and a sharp trailing edge such that a spike of at least 10 C is shorter than 2 seconds.

46. A probe according to any of claim 1-33 or 44, wherein said profile comprises at least one spike with substantially linear-rate temperature changes.

34. A method of stimulating tissue using a heat probe, comprising:

providing a heat sink/source at a temperature different from a neutral temperature relative to a tissue to be stimulated;

contacting said tissue with a heat control element, which heat control element is in thermal contact with said sink/source; and

controlling said stimulation by selectively varying a power of said heat control element to generate at least one of a heat pulse and a cold pulse.

35. A method according to claim 34, wherein said heat sink/source comprises a heat sink.

36. A method according to claim 34 or claim 35, wherein said heat control element comprises a heater.

37. A method of controlling the application temperature of a probe, comprising:

providing a relatively large thermal mass at a first temperature;

providing a relatively small thermal mass at a second temperature,

which small thermal mass includes an active electrically controlled temperature control element and

which relatively small thermal mass is in thermal contact with said large thermal mass and

which small thermal mass is adapted to apply an application temperature to a body part in contact therewith,

said small thermal mass having a thermal mass less than one quarter the thermal mass of said large thermal mass; and

controlling the application temperature by controlling the active element in a manner which generates an application temperature of said small thermal mass other than said first temperature,

said controlling the application temperature comprising offsetting a thermal effect of the large thermal mass on said application temperature by said controlling said active element of said small thermal mass.

38. A method according to claim 37, comprising stopping said active element to produce a sharp change in temperature of said small thermal mass.

39. A method according to claim 37 or claim 38, comprising powering said active element to produce a sharp change in temperature of said small thermal mass.

40. A method according to any of claims 37-39, wherein said first and second temperatures are different.

41. A method according to any of claims 37-40, wherein said thermal masses have a ratio of over 1:

50.

42. A method according to any of claims 37-40, wherein said thermal masses have a ratio of over 1:

100.

43. A method according to any of claims 37-40, wherein said thermal masses have a ratio of over 1:

1000.

45. A method according to any of claims 37-43, wherein controlling comprises generating at least one sharp temperature spike of at least 10°

C. including a sharp leading edge, a duration of less than 2 seconds and a sharp trailing edge.

47. A method according to any of claim 37-43 or 45, wherein controlling comprises controlling in a manner which generates a temperature spike with substantially linear-rate temperature changes.