Apparatus and method for micro-electric medical stimulation of cells of living animal tissue

• US 4,738,250 A
• Filed: 10/01/1985
• Issued: 04/19/1988
• Est. Priority Date: 10/01/1985
• Status: Expired due to Fees

• Current Assignee: MEMS Technology Incorporated
• Original Assignee: MEMS Technology Incorporated
• Inventors: Fulkerson, Melvin A., Tretter, Joseph P., Jacobson, Wyman E., Van Dierendonck, John
• Primary Examiner(s): Kamm, William E.
• Application Number:
  US06/782,427
• Time in Patent Office: 931 Days
• Field of Search: 128/419 R, 128/429 R, 128/422, 128/423 R
• US Class Current: 607/50
• CPC Class Codes: A61N 1/326 for promoting growth of cells, e.g. bone cells

Abstract

A medical electrical apparatus impresses a bipolar, low frequency voltage wave form through spaced-apart electrodes, across a damaged area of living animal tissue to cause a low, bipolar, current to flow through the damaged area to increase the metabolic activity of viable cells in that area and hence to accelerate healing. The current flow is monitored and used to control the magnitude of the voltage wave to cause the magnitude of current flow to be within the desired parameters. The frequency, wave form and voltage of the impressed voltage wave and the current flow are all below a level which can damage typical living cells.

Claims

1. A treatment method of increasing the metabolic activity of preselected cells in living animal tissue including the steps of:

A. situating a pair of spaced-apart electrodes in contact with healthy animal tissue on opposite sides of an area containing cells to be treated; and

B. externally inducing a percutaneous flow of electrical current between said electrodes through said area by impressing an external bipolar voltage wave form across said electrodes at a frequency of between 0.1 and 1.0 Hz.

2. The method of claim 1 including the step of:

C. monitoring the current between said electrodes and adjusting the voltage wave impressed between the electrodes so that the current flow resulting from performance with Step B does not at any time exceed 900 microamperes.

3. The method of claim 2 including the step of:

D. confining the maximum flow of current between the electrodes in Step B to a range between 20 and 900 microamperes.

4. The method of claim 2 including the step of:

D. controlling the frequency of the voltage wave impressed across the electrodes in Step B to between 0.1 and 1.0 Hz.

5. The method of claim 4 including the step of:

E. selecting the wave form of the voltage impressed in Step B from among wave forms which when impressed on the electrodes according to the method of the claim will produce no insult to the animal tissue being treated.

6. The method of claim 4 including the steps of:

E. continuing the externally induced flow of electrical current between the electrodes and through the area containing cells to be treated for a predetermined treatment activation period;

F. terminating the current flow after the activation period;

G. repositioning the electrodes in contact with healthy tissue in adjacent but spaced relation to the area containing cells to be treated to provide a different path for current flow between the electrodes; and

H. repeating steps A-G until all portions of the area to be treated have been treated by current flow between the electrodes.

7. The method of claim 6 including the step of:

I. controlling the treatment activation period of induced current flow for each positioning of the electrodes to not less than 20 seconds.

8. The method of claim 7 including the step of:

J. limiting the activation period of induced current flow to not more than 20 minutes.

9. A treatment method of increasing the metabolic activity of preselected cells adjacent to damaged cells in living animal tissue and of reducing the concentration of free radicals adjacent the damaged cells resulting from the damage to those cells, said method including the steps of:

A. situating a pair of spaced-apart electrodes in contact with the living tissue on opposite sides of cells to be treated and in spaced, relatively close adjacent relation to such damaged cells;

B. inducing a percutaneous bipolar flow of current between said electrodes by impressing a bipolar voltage wave form across the electrodes; and

C. monitoring the power level between the electrodes to assure that a power level of the current and voltage is at all times insufficient to damage said cells.

10. An electrical medical treatment instrument for increasing metabolic activity of preselected cells of living tissue, said instrument including:

A. a source of direct electrical energy;

B. a pair of output terminals;

C. means for generating from said energy source a voltage wave of predetermined shape and magnitude and impressing it across said output terminals, said voltage wave being such as to never generate a power level sufficient to damage the preselected cells being treated, and being of a frequency and form which will not insult living tissue when impressed across adjacent areas of said tissue;

D. a pair of electrodes adapted to be positioned in spaced relation to each other, in contact with said tissue on opposite sides of, and spaced from, said cells to be treated, and each being electrically connected to one of said output terminals to induce percutaneous electron flow in said tissue; and

E. means to limit the flow of current in said tissue to less than that which can damage the cells being treated.

11. An electrical medical instrument for increasing metabolic activity of preselected cells of living tissue by producing an electrical treatment signal adapted for application to the tissue to thereby induce percutaneous electric current flow through the cells to be treated, including:

A. means for producing a plurality of periodic electrical treatment signals at a treatment signal frequency, each for a treatment signal time period, the treatment signal being characterized by first and second electrical parameters;

B. means for receiving information representative of a selected value of the first electrical parameter of the treatment signal;

C. means for monitoring the first electrical parameter of the treatment signal; and

D. means responsive to the means for receiving information and the means for monitoring the first electrical parameter for causing the second parameter of the treatment signal to increase during each treatment signal time period until the first parameter of the treatment signal attains the selected value, and for maintaining the first parameter of the treatment signal at the selected value for a remainder of each such period.

12. The instrument of claim 11 wherein:

A.(1) the means for producing treatment signals causes the first electrical parameter to be current of the treatment signals; and

(2) the means for producing the treatment signals causes the second electrical parameter to be voltage of the treatment signals.

13. The instrument of claim 12 wherein:

A.(1)(a) the means for producing the treatment signals causes magnitude of the current of the treatment signals to be within a range of about 20 to 900 microamperes.

14. The instrument of claim 12 wherein:

A.(2)(a) the means for producing the treatment signals causes magnitude of the voltage of the treatment signal to be within a range of about 0 to 30 volts.

15. The instrument of claim 11 wherein:

A.(1) the means for producing the treatment signals produces a bipolar wave of treatment signals.

16. The instrument of claim 11 and further incuding:

E. means for receiving information representative of a selected treatment signal frequency, connected to the means for producing the treatment signal to cause the treatment signals to have the selected treatment signal frequency.

17. The instrument of claim 16 and further including:

F. means connected to the medical instrument for prompting a clinician to enter the information representative of the selected treatment signal frequency.

18. The instrument of claim 17 and further including:

G. means connected to the medical instrument for producing a visual display of the selected treatment signal frequency.

19. The instrument of claim 11 wherein:

A.(1) the means for producing the treatment signal causes the treatment signal frequency to be within a range of about 0.1 to about 0.9 Hz.

20. The instrument of claim 11 and further including:

E. means for receiving information representative of a selected activation time period, connected to the means for producing the treatment signals to cause the treatment signals to be produced for the selected activation time period.

21. The instrument of claim 20 and further including:

F. means for prompting a clinician to enter the information representative of the selected activation time period.

22. The instrument of claim 21 and further including:

G. means for producing a visual display of selected activation time period.

23. The instrument of claim 11 wherein:

A.(1) means for producing the treatment signal causes the activation time period to be within a range of about 20 seconds to about 20 minutes.

24. The instrument of claim 11 and further including:

E. means for prompting a clinician to enter the information representative of the first electrical parameter.

25. The instrument of claim 24 and further including:

F. means for providing a visual display of the selected value of the first electrical parameter.

26. The instrument of claim 11 wherein:

D.(1) the means for causing the second parameter of each treatment signal to increase causes the second parameter to increase linearly during each treatment signal time period until the first parameter of the treatment signal attains the selected value and causes it to maintain the selected value for the remainder of the treatment signal time period.

27. The instrument of claim 11 wherein:

D.(1) the means for causing the second parameter of each treatment signal to increase causes the second parameter to increase nonlinearly during each treatment signal time period until the first parameter of the treatment signal attains the selected value and causes it to maintain the selected value for the remainder of the treatment signal time period.

28. The instrument of claim 27 wherein:

D.(1)(a) the means for causing the second parameter of each treatment signal to increase causes the second parameter to increase as a function of an exponential during each treatment signal time period until the first parameter of the treatment signal attains the selected value and causes it to maintain the selected value for the remainder of the treatment signal time period.

29. The instrument of claim 28 wherein:

D.(1)(a)(i) the means for causing the second parameter of the treatment signal to increase causes the second parameter of the treatment signal to increase in proportion to an exponential function (1-e^-t/K) where t is time and K is a constant.

30. The instrument of claim 11 and further including:

E. power supply means connected to the medical instrument; and

F. means connected to the power supply means for providing a visual initialization message when power is first applied to the instrument.

31. The instrument of claim 11 and further including:

E. means connected to the medical instrument for producing a visual display indicative of instrument operation input requirements.

32. The instrument of claim 11 and further including:

E. battery means connected to the medical instrument; and

F. means connected to the battery means for producing a visual display indicative of low battery power.

33. An electrical medical instrument for increasing metabolic activity of preselected cells of living tissue by producing an electrical treatment signal adapted for application to the tissue to thereby induce percutaneous electric current flow through the cells to be treated, including:

A. means for producing a plurality of periodic electrical bipolar treatment signals at a treatment signal frequency, each for a treatment signal time period, the treatment signal being characterized by first and second electrical parameters;

B. means for receiving information representative of a selected value of the first electrical parameter of the treatment signal;

C. means for monitoring the first electrical parameter of the treatment signal;

D. means responsive to the means for receiving information and the means for monitoring the first electrical parameter for causing the second parameter of the treatment signal to increase during each treatment signal time period until the first parameter of the treatment signal attains the selected value, and for maintaining the first parameter of the treatment signal at the selected value for a remainder of each such period;

E. means for preselecting a range of electrical parameters for acceptable operation of the medical instrument; and

F. means for aborting the periodic electrical treatment signals and returning the second parameter of electric treatment signal to zero upon the magnitude of any of the preselected parameters being outside of its preselected range.