NO148399B - ELECTROMEDICAL DEVICE FOR THERAPEUTIC TREATMENT OF LIVE CELLS AND / OR TISSUE IN A PREDICTED TREATMENT ZONE - Google Patents

Abstract

Electromedical device for therapeutic treatment of living cells and / or tissues in a predetermined treatment zone.

Description

The present invention relates to an electromedical device of the type specified in the introductory part of claim 1, which is suitable for therapeutic treatments of living cells or tissues and particularly in living beings, which cells or tissues on

cellular or tissue level requires a "bioelectrical" signal, as that term is defined below, to artificially stimulate the healing, growth or regeneration of the cells or tissue.

As used herein, the term therapeutic treatment means not only the promotion or stimulation of healing,

growth or regeneration of desirable cells or tissues, but also the promotion or stimulation of unwanted or undesirable cells

clay or tissue breakdown or destruction.

As used here, the term "bioelectric sig-

nal" a signal that activates either a mechanism that promotes cel-

lenes or tissue healing in a living being, or which promotes the breakdown or destruction of the living being's unwanted cells or tissues.

As the term "reactive transfer" is used here re-

it comprises either capacitive coupling or inductive coupling or a combination of these.

The invention will be particularly described in detail in the pre-

bonding with the promotion of bone growth or bone improvement or healing, as the device according to the invention has been spe-

specially developed for such an application. The device according to the invention can, however, be used therapeutically for all the bio-

logical processes that react or can be affected by bio-

logical signals.

It is well known among biologists that electrical activity is associated with most, if not all, cellular processes. It is of particular interest here that lesions, for example bone breaks or fractures, leg amputation etc. are normally followed by a so-called "lesion current", which can be registered as a current strength or a voltage. The important fact here is that the electrical activity observed after lesions is always different from that observed before lesions, i.e. that abnormal electrical conditions prevail after lesions. Although the relationship of this phenomenon to the actual cellular processes, for example in the healing or growth of tissue, has not yet been clarified, it has been observed that artificial control or change of the total electrical activity in the lesion area at certain times can contribute to faster healing.

In the particular case of bone healing, it is known that electrical phenomena are associated with both this process and normal bone formations. These electrical phenomena seem to be produced by the bone's and the surrounding tissue's voltage-generating or piezo-electric-like properties as natural phenomena and the most likely reason why the bone heals naturally in most cases. To study this electrical effect and to try to further promote bone healing, electrodes have been directly implanted in areas with bone lesions. In most cases, the controlled electrical parameter was a continuous, i.e. non-pulsating direct current. In the few cases where electrical input signals other than direct current were used, the overall effect was that a voltage appeared on the tissue level, which was bipolar with amplitude and frequency components that for one polarity were equal to the amplitude and frequency components for the opposite polarity, i.e. the operating voltage was sinusoidal (alternating current). Even with pulsating direct current, the voltage at the tissue plane was bipolar with amplitude and frequency components that were the same for both polarities.

In the other special case of tissue regeneration, it has long been assumed that electrical conditions at the amputation area, which are linked to the central nervous system, are the controlling factors in the regeneration. To artificially stimulate regeneration in mammals (rats), implanted electrodes with continuous direct current signals were used.

A partial recovery of the limb was achieved, which would otherwise not have occurred naturally.

In all the above-mentioned special cases and for most biological processes involving cell activity, it is clear that electrical conditions play an important role. However, most known attempts at healing to date have placed the greatest emphasis on the use of continuous direct current signals as a stimulation source. This entails several major disadvantages, such as:

A. Not all the information (or coding) that can be found

in the electrical energy or the signals when these are finally transferred at cell level are available, when only direct current and only current are used for the transmission.

B. The efficiency of the energy transfer is unnecessarily and severely limited. C. At the cellular level, selective stimulation cannot be achieved as a result of the above-mentioned disadvantages A and B. D. In the vast majority of cases, it is necessary to use implanted electrodes which are subject to certain limitations at the electrode/electrolyte interface. For example, no electrode material is completely inert at direct current with an arbitrary voltage drop when in contact with body fluids.

E. Use of implanted electrodes can be toxic due to weak Faraday reactions that even disappear, and the electrodes themselves are poisoned by long-term implantation.

F. Use of implanted electrodes where the stimulating source is also implanted requires surgical pre- and post-treatment.

G. Where the stimulating source is placed outside the living being and is connected by implanted electrodes together with conductors, there are infection routes through the skin from the surroundings to the body's cavities and internal organs with the consequent risk of external or internal infections.

From the foregoing, it will be understood that bone growth can be promoted by changing electrical potentials that exist

ters in the fracture or break areas. It has been established that the naturally occurring electrical voltage or the naturally occurring voltage difference, which starts from the limb's starting point and runs towards the far end of the limb, rises more or less linearly. However, when there is a fracture or a fracture, the normally occurring stresses change dramatically. It is assumed that the change in stress distribution is part of nature's mechanism for signaling the need for skeletal improvements with consequent bone growth. Although experimental and clinical data have not yet been sufficiently substantiated, sufficient work has been carried out to further assume that the change in stress distribution also signals the need for remediation as a result of damage to other

species, for example tight muscle tissue, broken muscle tissue as well as skin scrapings, lesions and cuts.

From Swedish patent document 362,791, an apparatus of the type in question is known, where a certain healing effect on a bone fracture can be produced by means of the magnetic field from a coil. However, this healing effect as a result of the coil magnetic field itself is not elaborated further and is obviously considered to be a side effect or a secondary effect. This is evident from the fact that primary devices are used in the form of at least one splint, at least one induction coil to be placed in the body together with the splint, an elongated electrode to be inserted into the bone, and another electrode to be inserted into or placed along the bone .

The arrangement of these primary devices is very complicated, not least when it comes to placement, where extensive operative interventions are necessary. In addition, it is even necessary to place or introduce electrodes into the bone itself, and after the bone fracture has healed, extensive operative interventions must again be carried out to remove screws, rails, induction coils and electrodes.

The device according to the present invention is characterized by what is indicated in the characteristic in claim 1. The device is thus based on the recognition that, when the driving signal special to the invention is used, a purely reactive coupling between the driving signal can be used and the body zone to be treated. The special driving signal can thus produce a desired and effective signal at the tissue level without the use of implanted electrodes and the like, i.e.

by using only a reactive coupling. Of course, it is possible to implant electrodes or other parts of the device according to the invention if this is preferred for some particular reason, but implantation is therefore not necessary, which is a decisive advance. In addition, far less discomfort is achieved for the patient as complicated electrodes etc., which must be implanted and removed again operatively, can be completely avoided.

In connection with the invention, benefit has been taken from previous experimental and clinical work as well as from further experimental and clinical work for the artificial generation of at least one desired electrical voltage in or over a predetermined tissue zone in a living tissue or being, in which the need for re- construction is to be signalled. This is achieved by transmitting electrical signals to the predetermined zone in the living tissue or being in order to increase the absolute value of the electrical voltage in the predetermined zone by producing electrical currents that are stronger in one direction than in the opposite direction. As a living body, even if it is a conductor with respect to electric current, also exhibits both capacitive and inductive properties, a reactive transfer is not only possible, but has also been shown to work well in practice. Accordingly, by establishing a pulsating electrical signal with a waveform whose rise time is different from its fall time, the above-mentioned electric current is produced which is stronger in one direction than in the opposite. The voltage drop produced by the electric current causes a different voltage distribution in and across the predetermined tissue zone,

and the effect is added to the naturally occurring voltage change to promote and accelerate the remedial mechanisms with the initiation of tissue growth, which is appropriate for cosmetic or disease-preventing reasons. As a further effect, a faster recovery of tissue that has been exposed to an injury, or a breakdown of unwanted tissue, can be produced.

Based on the fact that supporting the natural pulsating electrical voltage that occurs when tissue is injured in a living being promotes healing, one can expect the opposite results if this voltage is suppressed or reduced, although the experimental and clinical foundations are not yet complete. In this connection, it is known that in both malignant and benign tumors there are voltage differences which seem to suppress the body's ability to eliminate the abnormal cells. Suppression of such tumors can occur if the normally occurring voltage difference is changed so that the process which serves to eliminate unhealthy, or in reality foreign, body cells is initiated. There is only a limited experimental basis to support this theory. The present invention perhaps opens up the possibility of triggering immune rejection or other tumor-eliminating bodily mechanisms.

According to the present invention, the principle is used that a bioelectric signal at cell or tissue level in a living being will artificially stimulate the healing of the cells or tissues in the living being. Although this mechanism itself is currently not known, it is believed that the cell membranes that form boundary or contact surfaces between intra- or extra-cellular fluids behave in the same way as electrode/electrolyte contact surfaces. The biological processes which such occur at stimulable or non-stimulable cell membranes must be assumed to be dependent on voltage or voltage drop in the same way as the voltage or voltage-dependent processes that occur at electrode/electrolyte contact surfaces. In accordance with this, it is assumed that significant amounts of charge can be stored at the cell membranes due to double layer, adsorption, absorption and desorption phenomena. Redox processes can also occur at these contact surfaces. In other words, it is assumed that cell phenomena can be affected by what happens at a cell's membranes, that the membrane acts as an electrode and as a result will be affected by local voltage variations which can, for example, cause an absorption or desorption of a critical, chemical , undissociated or dissociated intermediate and effect the associated special healing process.

It is therefore believed that the application of the principles of the present invention will enable the combined use of voltage control together with an appropriate frequency content of the electrical signals at the tissue level for selective and effective artificial therapeutic treatment without the disadvantages mentioned above during the discussion of the prior art, paragraphs A-G.

In short, the device according to the present invention is thus an electromedical device for changing the electrical voltage in a tissue zone in a living tissue or being. Provisions have been made to produce a pulsating electrical signal having a waveform whose rise time is different from its fall time. These signals can be transmitted reactively to the predetermined zone to produce an electric current in the zone, which current in one direction is stronger than in the other direction.

In the device according to the invention, the reactive coupling can

of the driving signal is carried out in two ways. A capacitive coupling using electrode plates is preferred, since the intensity of the electric field strength can thus be controlled or adjusted by changing the distance of the electrode plates to a tissue zone that is

during treatment. A corresponding possibility for controlling or adapting the force intensity lies in the design of the electrode plates, and in this respect it is preferred that one electrode plate has a significantly larger area than the other, as stated in claim 2.

The arrangement of the apparatus according to the invention also opens up the possibility of designing the electrode plates as simple surface electrodes which can be placed in direct physical contact with the skin surface.

Alternatively, the device according to the invention can work with inductive coupling. The preferred inductive coupling by means of one or more coils provides special possibilities for controlling or adapting the field strength intensity, and furthermore such coils can be embedded or directly included in a bandage, e.g. a plaster bandage, around a limb undergoing treatment.

Regardless of the reactive coupling method used, the embodiment specified in claim 3 has proven to be very suitable, as it thereby provides the opportunity to set the most effective treatment, depending on how deep under the skin the treatment is desired to be concentrated or carried out. Rise times in the interval 0.1 - 0.0001 seconds have thus been shown to be most effective when treating deep-lying tissue, while rise times in the interval 5-1 seconds have proven to be most effective when treating skin tissue.

The invention will subsequently be explained in more detail in connection with a couple of embodiments and with reference to the accompanying drawings, in which: Fig. 1 and 2 show schematic diagrams of embodiments of an electromedical device according to the invention. Figs. 3 and 4 show schematic illustrations of electrical signals which are useful for explaining the effect in the schematic diagrams from Figs. 1 and 2. Figs 5 and 6 show an electromedical device according to the invention with a patient for which it is used and where part of the patient is shown schematically. Fig. 7 schematically shows a mechanical device according to the invention.

In fig. 1 shows an embodiment of a bioelectric signal according to the invention. The circuit in fig. 1 is generally a two-stage frequency tunable complementary astable blocking oscillator or astable multivibrator which produces a pulsating output voltage or electrical signal having a triangular waveform as shown in FIG. 3, across its output contact points 20 and 22. Each triangle waveform can e.g. have an adjustable duration and e.g. be a waveform with a duty cycle of 0.01 seconds, with a rise time of 0.0001 seconds and a fall time of 0.0099 seconds.

A pair of electrodes 50 and 52 are electrically connected to output contact points 20 and 22 via leads 54 and 55. The electrical energy having a sawtooth or triangular waveform is capacitively emitted by means of electrodes 50 and 52 to an "external load" 24 which shall represent a predetermined tissue zone in a living tissue or being in which an in vivo damage or abnormality occurs. In the case of bone healing, the load can be considered to be a patient's arm or leg that has a crack, fracture, or fracture in the bone region located between the electrodes. In this connection, it is preferred that one of the electrodes is placed further away from the tissue zone than the other and of a larger dimension in order to reduce the current density. This will subsequently be explained in more detail with reference to fig. 5.

In connection with the present invention, one benefits from the fact that an electric current can be induced in the living tissue or being by a reactive signal transmission. The living being constitutes a conductive medium whose resistance varies depending on the tissues and body fluids involved. Since a capacitor is established between the electrodes and the body, as will be explained in more detail later, the design in fig. 1 primarily an example of capacitive transfer. Referring now to the waveform in fig. 3, it will be seen that here a voltage is first applied between the electrodes 50 and 52 which rises during a very short period of time, denoted in fig. 3 at the points RST, which is followed by a falling voltage for a significantly longer period of time denoted at the points TU. The cycle is repeated with a rapid rise in voltage in the positive direction followed by a slowly falling voltage in the negative direction. The tension can be positive or negative growing, depending on the observer's definition. Rise time and fall time can also occur when the voltage is growing positively or negatively, and in the present invention the rise time is the part of the signal in fig. 3 with which the particular purpose is to achieve the desired therapeutic signal at the cellular level,

that is, the part indicated by the points RST in fig. 3. It is an important fact here that the release of electrical energy by the one in fig. 3 waveform to a living being causes an electric current in the tissue with the general character shown in fig. 4. As a result, with rapidly rising voltage, there will be a correspondingly high value of induced current in the tissue. At each rise of the voltage from a negative value to a positive value,

as can be seen from fig. 35, there will consequently be a correspondingly high current peak as shown in fig. 4, denoted by the points A, B, C. The slow reduction of the voltage from the positive value to the negative value causes a much weaker current to flow in the tissue, as indicated by the points C, D. In connection with the above, the the rising current either go in the positive direction, as shown in fig. 4, or it may rise in a negative direction, which happens with a delta voltage output signal where the voltage is rapidly negative increasing and then slowly positive increasing, which represents the reverse of the situation shown in fig. 3-

Due to the above phenomena, the current produced in the load, which represents a zone of the living tissue or being, has a strength in one direction that is greater than in the opposite direction. This electric current naturally produces voltage differences across the body tissue, and these differences are believed to modify and change the voltages at the contact surfaces of the cell membranes and the absolute value of the total voltage distribution along the predetermined tissue zone being treated. Hard, tissue that corresponds to bone structure normally lies much deeper than muscle tissue or significant amounts of soft tissue, which includes fluids that are normally found near the surface.

It is an important characteristic of the present invention that it causes a current to flow in the tissue in which the voltages at the cellular level are to be modified. When the tissue in the form of bone structure is deep below the surface of the body, the rise time for the voltage which is emitted to the electrodes 50 and 52 should therefore be long enough to enable penetration to the depth of the bone structure. This will cause a frequency content in the part of the transmitted signal where, as indicated by the points RST in fig. 3 corresponds to the limitations of the penetration depth determined by the electromagnetic eddy current effect. The rise time denoted by the points RST and consequently the frequency content of the in fig. 3 depicted signal is chosen so that the signal is able to penetrate to the deepest parts of the body in order to achieve the voltage changes that are necessary at the cellular level according to the present invention.

Por deep tissue, the maximum frequency content of the part of the operating or activation signal denoted by the points RST in fig. 3 conveniently lie in the area from approx. 10 Hz to approx.

10 kHz, which corresponds to a rise time of approx. 0.1 second to approx. 0.0001 second. For medium-deep tissues, it should be in the range from approx. 10 kHz to approx. 50 kHz, which corresponds to the rise time approx. 100 microseconds to approx. 20 microseconds. For subcutaneous tissue, it should be in the area of approx. 50 kHz to approx. 200 kHz, which corresponds to a rise time of approx. 20 microseconds to approx. 5 microseconds, and for skin tissue it should be in the range of approx. 200 kHz to approx. 1 MHz, which corresponds to a rise time of between approx. 1

and 5 microseconds. Normally, the activation signal should have a waveform whose fall time in relation to the rise time differs from each other by at least one order of magnitude, that is to say by at least a factor of 10.

It should be pointed out here that the just mentioned electromagnetic eddy current effect limits with regard to rise time for the waveform in fig. 3 must correspond to the limitations given by the kinetic reaction rates for the electrochemical processes that take place at the cellular level and which are necessary to

achieve the desired therapeutic effect.

Although in fig. 3 shown waveform has a relatively long fall time in relation to the rise time, it must be understood that a fall time with a shorter period than the rise time of the waveform can be used in the practice of the present invention. This is primarily because the penetration depth for the majority of the current induced in the tissue, which is produced during the fall time, can be regulated by setting the fall period in accordance with the limitations imposed on the induced currents' depth of penetration by the electromagnetic eddy current effect. This will prevent the majority of the induced currents from reaching the tissue being treated. Subsequently, the small part of the induced currents that actually penetrate the tissue being treated during the fall time will be able to be maintained for a period of time that is shorter than necessary to inhibit the electromagnetic processes at the cellular level, which occur during the rise time of the waveform and thereby produce the desired therapeutic effect by adapting the waveform's fall time.

Such fall times would typically be at least an order of magnitude, i.e. at least 10 times less than the rise time and would usually also be less than 10 microseconds, which corresponds to a frequency higher than 100 kHz.

From the foregoing, it will be apparent that the apparatus according to the invention can have different designs, as the rise time for

the activation signal should only deviate from the fall time by a factor

of at least 10, and that the circuit shown in fig. 1 is just an example.

Specifically, in fig. 1 the frequency of the triangular signal proportional to a power supply voltage 23, to the external load 24 placed across the circuit as well as to the value of a resistor 32 and a variable resistor 30. A transistor 25 is of the NPN type and a transistor 26 is of the PNP- the type. Both transistors have the normal emitter, collector and base electrodes. The transistor 25 conducts the power supply 23 via the resistors 30 and 32, charging a capacitor 28 sufficient to preload the emitter-base connection in the transistor 25, so that a point 27 becomes positive and a point 29 negative. A resistor 31 is connected between the emitter of the transistor 25 and a point 35. In that the collector of the transistor 25 is connected to the base of the transistor 26, it in turn causes the transistor 26 to conduct. When the transistor 26 conducts, a current flows through the primary winding 33 of a transformer 34. The secondary winding 36 of the transformer 34 is connected in such a way that the induced voltage further increases the base current supplied to the transistor 25. This self-amplifying effect causes a rapid increase in the current which passes through both transistors 25 and 26 until saturation is achieved in both transistors. The transistors 25 and 26 remain saturated during the rise time of the triangular wave, during which the capacitor 28 is charged, so that the point 29 receives a positive and the point 27 a negative voltage.

The rise time of the triangular waveform thus produced is controlled primarily by the inductance of the transformer 34, the resistance between base and emitter in the transistor 25 and by the capacity of the capacitor 28 with some secondary depending on the capacity of a capacitor 43 which is connected in series with the external load.

Continuing with the function of the one in fig. 1 described circuit to produce the pulsating output voltage, it is seen that when the induced voltage in the secondary winding 36 begins to decrease, the current flowing in the base electrode of the transistor 25 will also decrease, which in turn decreases the base current in the transistor 26. When the transistor 26 switches to the non-conducting state, the current in the primary winding 333 falls, which further reduces the induced secondary voltage in the winding 36. This latter self-reinforcing effect quickly switches the transistors 25 and 26 from saturation to cut-off and thereby brings the rising part of the triangular wave to termination. The voltage that was built up across the capacitor 28 during the pulse resets the emitter-base connection in the transistor 25 to the voltage level to which the capacitor 28 was previously charged. The capacitor 28 is now slowly discharged through the resistors 30, 32 and 3I3 and the power supply consequently produces the falling part of the triangular wave. When the capacitor 28 is completely discharged, the cycle of charging the capacitor 28 through the resistors 30 and 32 is repeated. The bioelectrochemical stimulation circuit in fig. 1 is characterized in that the signal generation frequency is determined by the speed with which the capacitor 28 reaches the base voltage at which the transistor 25 becomes conductive. In accordance with this, the values of the variable resistor 30, the fixed resistors 31 and 32, the power supply and the value of the capacitor 28 can be considered to be the essential RC timing factors in the circuit which determines the duty cycle, i.e. the triangle wave or pulse frequency. As described above, the pulse frequency will also be reduced when the power supply voltage is reduced. Also, any external load applied to capacitor 28 through capacitor 43 will increase the time required for the capacitor to reach the voltage required to activate transistor 253 if the circuit's frequency-determining capacity is increased. Therefore, an increase in the external load will appear as a decrease in the pulse frequency of the triangle waveform produced by the circuit. In accordance with this, the pulse frequency for the signal produced by the circuit in fig. 1 be inversely proportional to the sum of the rise time and fall time of the produced pulsating waveform.

Finally, in connection with the description of the circuit in fig. 1 it is mentioned that a diode 44 is necessary to suppress the large negative voltage peak which is formed across the windings of the transformer 34 at the end of each pulse as a result of the energy stored in the self-induction of the transformer 34. If it is not suppressed, this voltage peak will eventually damage the transistors 25 and 26. A capacitor 40 serves to reduce interference by suppressing extraneous high-frequency magnetic signals which can be directly picked up by the transformer's magnetically permeable core, and which could otherwise cause premature tripping of the circuit in fig. 1. Finally, it can be mentioned that a resistor 46 serves to remove the leakage currents Icbo of the transistors 25 and 26. If these currents are not removed during the period between the pulses, these currents would be reflected in the collector of the transistor 26 and increased by the transistor's beta. For the specially chosen transistors, this would, at an operating temperature of 35 to 40°C, increase the overall average current dissipation in the circuit in fig. 1 several percent.

Now that the general principles of the present invention have been explained in connection with the capacitive, reactive coupling shown in the design of fig. 1, it is understood that a reactive coupling in the form of an inductive coupling can also be used. This is realized as a result of the fact that living tissue is a conductive medium as explained above. In accordance with this, a voltage loop and a consequent induced current will appear in the selected zone if a magnetic flux which has a rate of change is emitted to the selected zone in the body to be treated. If the rate of change in one direction is significantly different from the rate of change in the other direction, a voltage and an electric current will be induced in the selected zone, which current and voltage have a course that normally corresponds to that illustrated in fig. 4. Although those skilled in the art will understand how magnetic flux can be changed to meet the conditions of the present invention, it is in fig. 2 shows a system where an inductive coupling method is used to achieve this result.

Referring now to fig. 2 which is compared with fig. 1

it will be seen that they differ in that the electrode in fig. 2 has been replaced with induction devices or coils 50a and 52a. The electrode plate 52 has been omitted, the output contact point 22 is connected to ground via a wire 56, and an operational amplifier 47 has been added to the circuit. The operational amplifier 47 is supplied with electric power via a 68 volt power supply as indicated in the drawing and is necessary because of the increased power requirements of the coils 50a and 52a compared to the power requirements of the electrode plates 50

and 52 for coupling similar voltage gradients in living tissue. The coils 50a and 52a are electrically connected in parallel and although

two coils are shown, one coil can also be used if this is desired, in order to make use of the present invention. The coils 50a and 52a are placed next to the load 24

and is preferably not in contact with it. The load 25 represents a limb of a patient undergoing treatment, in the same way as the load 24 in fig. 1 represents a patient's limb.

The electrical function of the circuit in fig. 2 as such is the same as the function of the circuit shown in FIG. 1. Even the amplitude of the pulsating output voltage measured between points 20 and 22 is the same in fig. 2 as in fig. 1, the operational amplifier 47 being incorporated as a downstream operational amplifier in the circuit from fig. 2.

The following must be explained here:

(1) There is a capacitive connection between an electrode and

a dissociated, conducting medium, and this is known as an electrical double layer capacity. This capacity can be used for the transfer of energy across the interface, and provided that the voltage across this interface is less than or equal to the voltage at which the Paraday reaction occurs, or that the time during which a reaction voltage is achieved is too short for it to occur a reaction, this energy is transferred without Paraday interference between the electrode and the conducting, dissociated medium with which it is in contact.

(2) Electric eddy currents occur in any dissociated or electrically conductive medium, in which there is a time-varying electromagnetic field produced by induction. This current is produced by the voltage loop which always encloses the magnetic flux which changes in force line density with time. If this medium is therefore normally conductive, this induction can be used to transfer energy to the medium. (3) The efficiency with which the electrical energy can be transferred to such a medium is directly proportional to the components of the maximum amplitude of the electrical signals appearing in the medium and the conductivity of the medium. (4) The penetration depth of the electrical energy will be inversely proportional to the frequency components of the maximum amplitude of the electrical signals occurring in the medium.

Based on (1) and (3) and the fact that cells, tissues and body fluids comprise dissociated and electrically conductive media, it has been shown that one can externally or artificially stimulate normal activity or cell healing or tissue healing in a living being such as bone tissue . This can be achieved, as will be explained in more detail below, by generating a pulsating voltage between electrodes which are placed at the living being, but not necessarily implanted in it. The pulsating voltage, when connected to the tissue, causes an electric current through the tissue, which current in turn produces a bipolar voltage in the tissue, one polarity of which has amplitude and frequency components that are different from the amplitude and frequency components of the opposite polarity. This bipolar voltage is believed to cause the above-mentioned bioelectrical signal which artificially stimulates the healing of the tissue.

This can also be achieved without placing the electrodes inside the living being °P without producing any Paraday reaction at the interface between the electrodes and the body. Therapeutic effects can also occur in cells or tissues by placing the electrodes directly on the surface of the living being, that is, at an interface between an electrical conductor and an electrochemical conductor or with a dielectric material placed between the electrodes and the body surface, that is, at a interface between a dielectric charge carrier and an electrochemical conductor, and based on (4), the transfer of electrical energy from the pulsating voltage source to the treatment area will be induced through or over the body surfaces. This is particularly desirable when you want to promote the healing of broken bones or fractures.

Based on (2) and (3) and the fact that cells, tissues and body fluids comprise dissociated and electrically conductive media, it has been shown that normal activity or healing of cells or tissues in a living being can also be externally or artificially stimulated and that this can be achieved by generating a pulsating voltage across an inductive device which is placed close to the living being. This inductive device will produce an alternating electromagnetic field which varies with time and which, when connected to a living being's tissue, will cause a voltage loop which then

again inducing an electrical current through the tissue. The induced current will then produce in the tissue a voltage which is bipolar and whose amplitude and frequency components of one polarity are different from the other polarity. This bipolar voltage is again believed to produce the above-mentioned bioelectrical signals which artificially stimulate tissue healing. This can even be achieved in the case where electrodes are used to connect the electrical signal to the body without the inductive device being placed in contact with the relevant living being. That is to say, a therapeutic effect can occur in the cells or tissues of a living being by using the inductive device in the vicinity of, but not in contact with, the surface of the body in question, and based on (4) the transfer of electromagnetic energy to the treatment area will take place through or above the intervening tissue. This is again particularly desirable to promote healing in the event of a broken bone or fracture.

Referring now to fig. 3 and 4, as mentioned above, at the output contact points 20 and 22, a pulsating output voltage is generated by the circuits from fig. 1 and 2, and which is illustrated with the one in fig. 3 showed triangular waveform. As mentioned, the amplitude of the output voltage produced by the circuit in fig. 2 the same as for the voltage produced by the circuit in fig. 1, and furthermore the waveform is largely the same, and for purposes of explanation, fig. 3 can also be used with reference to fig. 2.

The waveforms for the signals that occur at the external load in fig. 1, namely the external load 24, is illustrated in fig. 4. For the purpose of explanation, fig. 4 can also be used with reference to fig. 2. Therefore, the waveform of the signals appearing in the external load 24 is also illustrated in fig. 4 where the waveform is therefore representative of both the waveform of the current and the voltage drop at the load 24 and 25, that is to say at tissue level.

A complete waveform for the output voltage at contact points 20 and 22 is shown in fig. 3 of the points RSTU. A Fourier analysis for this waveform will show that the frequency components at maximum amplitude (the fundamental frequency and the first harmonic frequencies) are far higher in the part of the waveform indicated by the points RST than in the part indicated by the points TU.

In the circuit in fig. 1. are the electrode plates 50 and 52, and in the kets course in fig. 2 the coils 50a and 52a electrically connected to the output contact points 20 and 22 to cause an electric current in the loads 24 and 25. The manner in which this electric current is produced in each case will be explained in more detail below. It is of fig. 4 it is clear that the electric current on the tissue level in one direction rapidly increases from the strength shown at point A to a relatively greater strength at point B. The current then drops to the strength at point C and continues at this strength until point D, and then - the cycle is repeated. The fact that the current strength in one direction greatly exceeds the current strength in the opposite direction means that either a predominantly negative or a predominantly positive voltage is produced in the zone of living tissue, as may be desirable in order to vary the normally occurring electrical voltage in this, and that the growth of the tissue is consequently artificially stimulated. The prevailing voltage in the treatment zone, which can either be positive or negative, will be determined by the polarity of the activation or drive signal at the electrodes 50 and 52 and the coils 50a and 52a, respectively. for example, swapping the contact points 20 and 22 in relation to the electrodes 50 and 52 will cause a reversal of the signals as shown in fig. 3 and 4. The fact that a small electrical current flows in a direction that is not desirable for changing naturally occurring voltages, or in a counterproductive direction with regard to tissue growth, does not adversely affect the results of the therapeutic treatment that are achieved with the electric current flowing in the preferred direction being of an order of magnitude many times higher than that of the current flowing in the opposite direction. The one in fig. 4 shown 'tension on tissue level can therefore be considered to be bipolar, and the current which in one direction has far greater strength than in the other produces during the transmission of those in fig. 1 and 2, the circuit's electrical signals to the living tissue or being showed a voltage difference having predominantly a preferred polarity to avoid forced surgical, current-conducting implantation of electrodes in the tissue to be treated. The size of this current is directly proportional to the relative values for the frequency components of it in fig. 3 showed the waveform's maximum amplitude.

It follows from the above that the relatively higher values for the frequency components of the maximum amplitude in the part of the waveform in fig. 3 which is described by the points RST will be expressed in a large total value for the current produced in the load (24 or 25), where as shown in fig. 4 is indicated by the points ABC. The positive direction of this generated current, whose waveform is indicated by points A, B, C in fig. 4 reflects the upward direction of that in fig. 3 showed signal line or drive waveform slope or rate of change. Correspondingly, the relatively low values of the frequency components at maximum amplitude, and which occur in the part of the waveform in fig. 3 which is indicated by the points TU, is expressed in the low total magnitude of the produced current strength in the load 24 or 25, as in fig. 4 is indicated by points C-D. The negative direction of this generated current whose waveform in fig. 4 is indicated by points C, D, expresses the result of the downward direction of that in fig. 3 showed the drive waveform slope or rate of change.

From the foregoing, it will be understood that the amperage produced in the load 24 and 25 is produced in such a way that it expresses the relative values of the frequency components at maximum amplitude which is depicted in fig. 3. That is, a Fourier analysis of the waveform in fig. 4 will show that the frequency components with maximum amplitude are of a much higher frequency in the part of the waveform indicated by points A, B, C than in the part indicated by points C, D. Furthermore, it can be seen from fig. 4 it can be seen that a voltage is produced on tissue level which is bipolar with an amplitude and with frequency components, one polarity of which is different from the other polarity, and that the maximum amplitude of the signals in fig. 4 forward

arrives at point B.

As reference is now again made to fig. 1 it can be seen that the placement of the electrodes in relation to the desired treatment zone or in relation to the damage is such that the electrode with the greatest current density, that is the smallest electrode, is closest to the area where the therapeutic treatment is desired. In the following, the electrode 52 will be called the working electrode. The second electrode, the electrode 50, which will be called the counter electrode in the following, is designed for minimal current density, thereby, as will be explained later, to avoid any counteraction of the healing or healing effect of this electrode, and to keep side effects such as nerve damage , at a minimum, this is placed with a view to optimal voltage distribution. The electrodes 50 and 52 can be made up of any conductive or semi-conductive material. The requirements for the electrode material are: (1) that it does not react to the skin and, for example, cause infection or swelling, (2) that it does not polarize too strongly for healing to occur when body fluids are present, so that the desired energy and frequency content of the signals at cell or tissue level can be available in the right place.

Silver is the preferred material for designing the electrodes 50 and 52, but other suitable materials can also be used.

It should be noted here that the electrodes 50 and 52 can be placed in direct physical contact with the epithelial surfaces of the body being treated, and in this case such physical contact will be an electrical-electrochemical interface, or

a suitable dielectric material, such as for example "Mylar" or even air, can be placed between the electrodes and the body's epithelial surface, and in this case such a physical contact will be a dielectric-electrochemical interface.

In the case of an electrical-electrochemical interface, the maximum voltage or the time during which this is emitted to a given electrode is selected, according to the present invention, so that Faraday reactions are avoided. Measured between the electrodes 52 and 50, the maximum voltage emitted between the electrodes 50 and 52 is advantageously in the range of approx. 0.8 volts to approx. 1.0 volts in the positive direction and in the range approx. 0.0 volts to approx. -0.1 volts in the negative direction.

These Faraday reactions can include local changes in the pH value, local changes in tonicity (so-called osmolality), destruction of necessary proteins, lipids, etc. or electrolysis in the physiological salt solution by evolution of the gases included in this (E^, Cl^ and 0^).

If the working electrode has to be applied a normally undesirable high voltage, i.e. over approx. 1 volt, to effect the desired healing in the tissue zone, tissue necrosis or other deleterious tissue effects can be avoided simply by holding the working electrode at this abnormally high voltage for a period of time less than that. which is necessary for Faraday reactions to occur. The exact upper limit for. the time period will depend on the voltage drop, above. the interface between .working electrode and tissue. This latter voltage drop is not directly measurable. However, a measurable voltage drop can be achieved between the working electrode and a reference electrode. This measurable voltage drop is composed of two components, namely the voltage drop across the interface between the working electrode and the tissue, which voltage is responsible for the presence of Faraday reactions, and the voltage drop caused by the voltage drop across the tissue lying between the working and reference electrodes. the.. Expressed by the measurable voltage drop, the permissible time period's upper limit is therefore dependent on the following factors: The working electrode's area and geometry, the tissue's geometry and the conductivity between the working and reference electrodes, all of which are co-determining for the voltage drop across this tissue volume. The voltage drop due to the impedance of the tissue and body fluids when this is vectorially subtracted from the measured voltage drop between the working and reference electrodes, give the voltage drop across the interface between the working electrode and the tissue. The latter voltage drop will in turn be an expression of the most important electrochemical reactions at this interface and consequently also their kinetic reaction rates. From their speeds, the maximum time can again be derived, i.e. the upper limit of the time period, where it can be allowed for the working electrode to have a voltage drop that is greater than that which will initiate Faraday reactions at the interface between the working electrode and the tissue for long periods of time. With a working electrode voltage of from approx. 1 volt to approx. 100 volts measured in relation to a reversible hydrogen electrode (RHE) in the same electrolyte, i.e. tissue, the working electrode can appropriately only maintain these voltages for approx. 500 microseconds to approx. respectively 1 nanosecond with a working electrode area of 1 cm, before harmful Faraday reactions occur at the working electrode's interface with the tissue.

For a working electrode voltage from approx. -0.01 volts to approx.

-100 volts measured in relation to RHE1 one in the same electrolyte, i.e. tissue, the working electrode can correspondingly only remain at these potentials for approx. 50 microseconds to approx. 1 nano-

and 2

second at a working electrode area of 1 cm before harmful Faraday reactions occur at the interface between the working electrode and the tissue.

As a summary of the above and according to the invention, it can be stated that Faraday reactions are avoided in the case of an electrical-electrochemical interface by an undesired high voltage applied to the electrode tissue interface for a period of time, which does not exceed from 500 microseconds to approx. 1 nanosecond per cm<2 >electrode surface, as the Faraday reactions mentioned have time constants that are much longer than those that apply to charging and discharging the double layer capacity. When this time or frequency limitation cannot be met, it is necessary that the amplitude of the voltage measured across the working electrode and a RHE in the same electrolyte (tissue) does not exceed +0.8 to +1.0 volts in the positive direction or approx. 0.0 volts to approx. -0.1 volts measured between the working electrode and a hydrogen reference electrode in the same electrolyte in the negative direction to avoid the above-mentioned Faraday reactions. These voltage limitations apply to those electrodes, i.e. platinum group metals, whose ions do not dissociate to any significant extent when the voltage is changed from the electrode's normal equilibrium or standard voltage. A narrower, i.e. more limited voltage range must be used for most other electrode types.

In the case of the dielectric-electrochemical interface, the problem of Faraday reactions does not exist at the body's epithelial surfaces.

As reference is now again made to fig. 1, 3 and 4, the pulsating output voltage produced by the circuit in fig. 1, as indicated above at the output contact points 20 and 22, and as mentioned above, the output voltage is illustrated by the sawtooth or triangular waveform shown in fig. 3. The pulsating output voltage is an alternating current and capacitively coupled to the electrodes 50 and 52 via the capacitor 43. This type of coupling ensures that no direct current components occur at the contact points 20 and 22. The capacitor 43 can be omitted in those cases in which the electrodes 50 op, 52 have a dielectric material between them and the surfaces to which they are attached, for the reason that a capacitor is effectively formed at the electrode, the dielectric material and the body surface in each case. The resulting capacitor will effectively block DC components.

Usually, the flow on tissue level appears with the one in fig. 4 showed a current waveform in that the output voltage occurring at the contact points 20 and 22 is placed over a capacitor which is in series and/or parallel with an impedance. The capacitor is formed by the double-layer capacitor that occurs between the electrode plates 50

and 52 which are placed on the body's surfaces and the dissociated substances in the tissue fluids. The impedance is the tissue's impedance to ion movement through the tissue and all other electrochemical processes involved, i.e. redox processes, adsorption and desorption processes. The bipolar voltage at the tissue level, whose voltage drop waveform appears in fig. 4, is the result of the voltage drop caused by the flow through, the impedance of the tissue and body fluids.

It is assumed that in fig. The apparatus shown in 1 works for the purpose in question, as the current strength and the amplitude of the resulting bipolar voltage on tissue level, the pointed peak Y in fig. 4, is higher than what is necessary to produce the desired stimulation during the ascending part of the triangular pulse, that is to say greater than necessary to produce the bioelectric signal. The current strength and the amplitude of the bipolar voltage as in fig. 4 is indicated at points C, D, and both of which are produced at the tissue level, are below the levels necessary to cause stimulation, that is to say below the level that causes the bioelectrical signal.

As a result, the electrode plate 50 or 52, which is closest to the desired treatment zone, appears to be negative or positive in relation to the adjacent cells or tissue. This result is achieved despite the fact that the average current passing through the system is zero. The prior selection of the area for the electrode of positive or negative polarity with respect to the adjacent body surfaces will be explained in more detail below. Normally, however, one of the electrode plates 50 or 52 is placed closer to the desired treatment zone than the other electrode plate. The preferred position of the electrode plates 50 and 52 is close to the epithelial surfaces of the living being or patient being treated. The term close to means as used here, closely lying, adjoining, touching or adjacent. When, for example, the plates 50 and 52 are in direct physical contact with the body surfaces, the plates will touch the body surface, while, on the other hand, the plates will be close to or close, that is, in the immediate vicinity of the body surface when a dielectric material is placed between the plates and the body surfaces.

However, it is clear that the electrodes 50 and '52 can also be designed so that they can be implanted in the treatment zone. That is, both electrodes can be designed as needle electrodes, or alternatively one can be designed as a needle and another electrode as a plate. The preferred location of the electrodes is, however, external to the epithelium of the living being. A method without intrusion is preferred, since the signals produced in this way by the circuit in fig. 1 can be connected to the treatment zone without creating a discontinuity in the epithelium, whereby the risk of superficial or deep infection in the patient undergoing treatment is avoided.

It must also be explained here that although a battery with one or more electrochemical cells is the preferred design for the power supply 23, other suitable known electrical power supplies can also be used. The entire circuit in fig. 1, if desired, is cast in a molding compound that is compatible with the body's environment, with or without incorporating the power supply. In the latter case, the power supply can be electrically connected to the electrical circuit by means of suitable contact points placed in the embedment. This makes it possible that the battery can be replaced during treatment if necessary and that the electronic circuit components can be used again, which would not otherwise be the case if the batteries were embedded together with the components during the production of the circuit from fig. 1. Furthermore, one of the electrodes 50 or 52 can be designed as a plate which is attached to the embedment which encapsulates the electronic components. In this case, the plate must of course be appropriately connected to the electronics inside the embedment. Correspondingly, one or both of the electrodes 50 or 52 can be designed after a rail, the wall of a rail, a plaster cast or a bandage that lies around the treatment zone. It should also be mentioned here that the circuit in fig. 1 can also be embedded or embedded in a material that is unaffected by and does not itself affect the materials used to form the embedding of a broken or fractured limb and the embedding of other body parts. The reason for this is that the circuit from fig. 1, if desired, can be embedded in the casting to fix or support the limb or the other body part, which has been broken or fractured

bone.

The embedded or encapsulated circuit of FIG. 1 can, if desired, also be completely implanted in the body of the patient undergoing treatment. In this case, a coating of silicone rubber and similar material can also be used. That is, the embedding material can have a paper-thin film of silicone rubber formed around it.

Those in fig. 2 shown coils 50a and 52a can be constructed from any conductive or semi-conductive material. The most important requirements for the coils are: (1) that these are placed so that they do not necessarily touch the body surfaces involved and so that the associated electromagnetic field produced by these, while this varies, produces voltage loops and induces eddy currents in the desired areas, and (2) that the coils are constructed of a material that has no significant impedance to the electric current at the voltage gradients that normally occur in this circuit.

The preferred design of coils 50a and 52a is silver, although other suitable materials such as copper may be used.

The coils are preferably placed in such a way in relation to the damage that the most concentrated electromagnetic lines of force pass through the damage area at right angles to the preferred current direction, as will be explained in more detail below. These coils are also preferably designed and placed so that they spread the current, i.e. make the current density small, in the areas of the body or in the surrounding tissue that are not in the immediate vicinity of the damaged area in order to reduce any side effects such as, for example, a negative healing effect.

Referring now to fig. 2, 3 and 4, it appears as mentioned above the contact points 20 and 22 in the circuit from fig. 2 a pulsating output voltage as illustrated by the triangular waveform shown in FIG. 3. As mentioned above, the amplitude of the output voltage produced by the circuit of fig. 2, the same as the amplitude produced by the circuit of FIG. 1, and furthermore the waveform is largely the same, and fig. 3 and 4 will again at this point only be used with reference to fig. 2 for explanatory purposes. The pulsating output voltage is capacitively coupled to the operational amplifier 47 via the capacitor 43. The capacitor 43 can actually, if desired, be omitted in the circuit from fig. 2, as no direct current components can occur in the load 25 due to the inductive coupling of the output voltage to the load 25 in this case.

As a result of the pulsating output voltage or triangular waveform being applied across the coils 50a and 52a, a pulsating current is produced in the coils 50a and 52a which causes a pulsating time-varying electromagnetic field in the vicinity of the load 25 which is a modulated electromagnetic field of triangular waveform and which is coupled to the load 25 by means of the position of the coils in relation to the load 25.

The waveform of the signals appearing in the load 25 is, as mentioned above, illustrated in fig. 4. The one in fig. 4 illustrated waveform represents, as mentioned above, the voltage drop and the induced current waveforms at tissue level. Those skilled in the art will appreciate that the remarks made above with respect to the waveforms shown in FIG. 3 and 4, in terms of the bipolarity of the voltage arising from the load and in terms of a Fourier analysis of these waveforms would show, fits with this.

Typically, the tension loop is produced on the tissue plane by application of the modulated, triangular wave-shaped electromagnetic field produced by the coils 50a and 52a through the tissue perpendicular to the desired current direction on the tissue plane. This voltage loop produces a current which in turn causes the bipolar voltage at tissue level. The voltage drop and the current waveform as shown in fig. 4, is the result of the voltage drop produced by the current, which passes through the impedance of the tissue and body fluids.

It is assumed that the apparatus in fig. 2 fulfills said purpose, as the amplitude of the bipolar voltage produced at tissue level (its pointed peak B in fig. 4) in the growing part X of the triangular wave in fig. 3

in its rise time is above the size necessary to produce the bioelectric signal. The magnitude of the current and the amplitude of the bipolar voltage shown in fig. 4 at the points C, D, which are produced on tissue plane in the falling time of the triangular wave or decreasing part Z in fig. 3 is lower than the level necessary to cause stimulation, that is to say lower than the level necessary to cause the bioelectrical signal. As a result, intermediate cells perceive the voltage drop through the tissue as a polarity associated with the tissue, i.e. that one end

or part of the zone under treatment appears to the intermediate cells to be positive, while the other end or part appears to be negative, even though the average current passing through the system

is zero.

It should be mentioned here that the coils 50a and 52a are usually positioned in such a way in relation to the desired stimulation zone that the electromagnetic field strength is maximum in this zone. The preferred location of the coils 50a and 52a is close to, but not necessarily in contact with, the surface of the skin of the patient undergoing treatment, but the coils 50a and 52a can also, if desired, have such a design that they can be placed on the surface of the patient's skin, or a design that allows these to be implanted in the treatment zone. Both coils can be designed as flattened coils with pointed edges, or alternatively one can have the aforementioned geometry, while the other coil can be designed as a small ferrite core inductor.

It should also be mentioned here that the power supply 23 together with the 68 volt power supply for the operational amplifier 47 is a battery or batteries which each comprise one or more electrochemical cells. Other suitable electrical power supplies can be used if desired. If desired, the entire circuit from fig. 2 is embedded in an implanting compound that is compatible

■with the body's environment (the human body included) with or without the integration of the power supply. In this latter case, the power supply will be electrically connected to the electrical circuit by means of suitable contact points, which are arranged in the embedment. This feature enables the batteries to be replaced during processing if necessary, and it also enables the electronic circuit components to be reused, which would not normally be the case if the batteries were encapsulated together with the components that make up the circuit from fig. 2. The coils 50a and 52a can further each be designed as a wound coil which is attached to the embedment housing of the electronic components. In this case, the coils can of course be suitably connected to the electronics inside the encapsulation container. Each of the coils 50a and 52a can likewise be adapted to the shape of a splint or the wall of a splint, a cast or a bandage about the damaged area. It should also be pointed out here that the circuit from fig. 2 can also be embedded or embedded in a material that is compatible with the environment of the materials used to form embeds for broken or fractured limbs and other body parts. The reason for this is that, if desired, the circuit in question can be embedded in the casting, to hold or support the limb or other body part that has a broken or

fractured bone.

The encapsulated circuit of FIG. 2 can also be completely implanted in the patient's body during treatment if this is desired. In this latter case, a coating of silicone rubber or other similar material can also be used. That is to say, the embedding material can be surrounded by a thin silicone concave layer.

However, as mentioned, the preferred location of the coils is outside the body's epithelial surfaces, a non-invasive surgical method being the preferred one for connecting the electrical energy to the living being using the principles of the present invention.

While emphasis has so far been placed on the therapeutic treatment of bone tissue as a concrete example of application of the device according to the present invention, it is clear that the biochemical activity at the cell membranes lends itself to control from the outside. Therefore, the device according to the present invention will be able to produce an effective stimulating or healing effect in the following areas:

(1) Growth.

(2) Restoration and rectification.

(3) Conversion.

(4) Malignant disease states.

(5) Therapeutic pain control.

(6) Therapeutic muscle and nerve control.

(7) Infection.

These possible areas of application mean that the device according to the present invention can probably be used in such areas as bone repair or healing of fractures, suppression of cancer, regeneration of limbs, repair of soft tissue and thrombosis. In other words, all the biological processes that exhibit abnormal electrical conditions can be favorably influenced by a correctly programmed device according to the invention.

With regard to the circuits from fig. 1 and 2, the term correctly programmed means as a result that it includes variations in the frequencies, the duty cycles, the rise times of the waveform, the fall time of the waveform as well as the polarity of the output voltage produced by the circuit from fig. 1 and 2. Those skilled in the art will appreciate that these factors determine the characteristics of the output voltages produced by the circuits of FIG. 1 and 2. With respect to the duty cycle, the rise time and the frequency, variations can be produced by varying the resistor 30, the capacitor 28 and the power supply 23. As regards the fall time, variations can be produced by changing the inductance of the transformer windings, for example by replacing one transformer with another , and with regard to polarity variations, these can be produced by reversing the transmission links 54 and 55 in the circuit from fig. 1 or the transmission links 54 and 56 in the circuit from fig. 2.

If it concerns the circuit from fig. 1, correct programming also means that the location, the electrode plate area and the electrode plate geometry are included. That is to say, these latter factors control the strength and the area with which, respectively, via which the energy is transferred from the circuit in fig. 1 to the predetermined zone of the living being being treated. Where bone healing, wound healing and tissue regeneration are concerned, for example, the preferred design of the electrode plates is an arrangement on the working or the negative electrode plate 52 is over the treatment area, and the counter electrode plate or the positive electrode plate 50 is placed over an area where a possibly facing or the opposite effect in relation to the desired effect is either not harmful, or neither can nor will occur. Usually, the working electrode or the electrode that is to produce the desired stimulating or healing effect has an area of approx.

1/5 of the counter electrode or the opposite electrode plate, and the shape of the electrode plate is chosen so that the concentration of the electric field is as close to the desired treatment area as possible. Where it is a question of cancer retraction, breakdown or destruction of unwanted tissue, the same criteria can be applied when it comes to plate shape, arrangement, etc.,

however, it is assumed that the polarity of the electrode plates should be reversed, i.e. that the electrode plates should be placed opposite to what they become during bone healing, wound healing and tissue regeneration.

In the case of the circuit from fig. 2 means correctly programmed that placement, coil volume and coil geometry are included. These latter parameters control the strength and the area over which the energy is transferred from the circuit in fig. 2 to the tissue zone in the living being that is being treated. Usually, the therapeutic coil geometry is chosen so that the highest field concentration, i.e. the maximum flux density, is S t3.ett at the desired treatment area as possible.

In fig. 5 shows an electromedical device of the one in fig. 1 shown type with a patient for which this is used, and with schematically shown parts of the patient. The working electrode or the negative electrode 52 sits close to the area being treated,

and the counter electrode or the positive electrode 50 is placed far away from the area under treatment. By means of a block 100, a circuit that can generate an electrical signal is denoted. which pulsates in both positive and negative directions, and which has a waveform whose rise time differs from the fall time. With such an arrangement, a current will be generated in a part 102 of the patient undergoing treatment during the undulations of the operating signal generated by the circuit in the block 100. The current strength in the direction from the vicinity of the limb 102 to the farthest region of the limb will be stronger than in the opposite direction direction. The magnitude of the strongest current will correspond to the current signal as in fig. 4 is indicated by points A,

B, C, and the smallest magnitude of the current, which goes in the direction from the distant region to the vicinity of the limb 102, will correspond to the current signal as in fig. 4 is indicated at points C, D. As a result of this current, a bipolar voltage will be produced in and across the treatment zone, which alternates in both positive and negative directions so that the maximum amplitude of the bipolar voltage in one direction is greater than the bipolar voltage maximum amplitude in the opposite direction, that is to say correspond to the voltage drop waveform from fig. 4. The thus established bipolar voltage in the treatment area has predominantly negative polarity, which increases the absolute value of the naturally occurring electrical voltage in the treatment area, and it is assumed that this bipolar voltage can be added to the naturally occurring voltage change that occurs in the event of injury to promote and speeding up the repair mechanism by subsequent higher reconstitution rate of the damaged bone.

In fig. 6 shows an electromedical device of the one in fig. 1

shown type with a patient for which it is used, and with schematically shown parts of the patient. A single coil 202 is seen which is

brought over the treatment area so that this is as close to the treatment area as possible. A block 200 represents a circuit that can generate an electrical signal that pulsates in both negative and positive directions, and that has a waveform whose rise time is different from its fall time. With the arrangement shown in fig.

6, a pulsating current is produced in the coil 202 which in turn causes a pulsating, time-varying electromagnetic field. which, due to the position of the coil 202 in relation to the part 102 of the patient, is connected to the part 102 during the undulations of the operating signal produced by the circuit in the block 200. It appears on tissue-

plan a voltage loop which in turn causes in the part 102 a current which in turn produces a bipolar voltage in and across the part 102 of the patient. The electromagnetic field produced by the coil 202 is perpendicular to the desired current directions, and the current pulses in both negative and positive directions in the part 102 of the patient. The size of the current that runs in the direction from the near area of the part 102 to the far area of the part 102 will be greater than the size of the current that runs from the far area of the part 102 to its near area. The larger current corresponds to the current signal as in fig. 4 is indicated at points A,B,C, and the smaller current corresponds to

affects the current signal indicated at points C, D. As a result of this current, a bipolar voltage will be established in and across the treatment zone which alternates in both positive and negative directions and where the maximum amplitude of the bipolar voltage in one direction is greater than the maximum amplitude of the bipolar voltage in the opposite direction, i.e. corresponding to the voltage drop waveform from fig. 4.

The thus produced bipolar tension in the treatment area

has predominantly negative polarity, which increases the absolute magnitude of the naturally occurring electrical voltage in the treatment area, and it is assumed that this bipolar voltage can be added to the naturally occurring voltage change that occurs in case of injury,

to promote and speed up the repair mechanism with a subsequent higher reconstitution rate for the damaged bone.

Although so far only electronic circuits have been mentioned

Those skilled in the art will understand that a mechanical device, capable of producing either a pulsating electrodynamic or electromagnetic field that rises and falls in accordance with a predetermined frequency, and

i the field's rise is different from its fall time, will cause a current on the tissue plane in accordance with the instructions of the present invention. Such a mechanical device is shown in schematic form in fig. 7 where a magnet 302 rotates about an axis 304. An element 306 is a plate of a material impermeable to the magnetic field of the rotating magnet 302, and the element 306 has a triangular opening 308. Those skilled in the art will understand that when the poles of the magnet 302 are rotated past the opening 308, an electromagnetic field is formed on the other side of the element 306 which rises and falls in accordance with the rotation speed of the magnet 302. The build-up time of the generated magnetic field will also be different from its fall time due to the triangular opening 308.

It should be remembered that the broadest area of the present invention is the treatment of living cells using the properties, at the contact surfaces of the cell membranes, which means that cell membranes behave as electrodes. In accordance with this, cell membranes will react to local voltage variations even though nerve cells, due to their special structure and special sensitivity, may be among the cells most affected by the local electrical voltages described above, it is not only the purpose of the present invention to stimulate nerve cells, although this may be a necessary step in a healing process, but also to stimulate other susceptible cell or tissue types, which is necessary to achieve the desired final effects in the form of healing or restoration of the desired tissue types , or alternatively in the form of the possible breakdown or destruction of unwanted tissue.

Although reference has been made in the present invention to concrete mechanism phenomena which are connected with cell and tissue healing, it must be understood that in many areas the actual processes involved have not yet been fully understood. Those that have been put forward have only been attempts at an explanation of the fact that the devices described work for the purposes mentioned.

In a practical embodiment of the present invention, they can, in connection with fig. 1 mentioned components have the values stated in table 1.

In a practical embodiment of the present invention, they can, in connection with fig. 1 mentioned components have values that are indicated in table 2:

Claims (3)

1. Electromedical device for therapeutic treatment of cells and/or living tissue in a predetermined zone in a living body, where the device comprises an organ for generating a wave-shaped electrical signal, and electrodes for reactive coupling of a signal to the predetermined treatment zone, characterized in that the signal generating device is arranged to be set to generate a driving signal (Fig. 3) with a waveform, where the wave's fall time (TU) differs from the wave's rise time (RST) by a factor of at least 10, and that the signal generating device is arranged to emit a driving potential to the electrodes for a period of time that does not exceed from 500 ^s to 1 ns per cm 2 electrode area. 2. Apparatus in accordance with claim 1, where the electrodes are two separate electrode plates (50, 52), characterized in that one of the electrode plates has a surface which is considerably larger, preferably approx. five times larger than the surface of the other electrode plate. 3. Apparatus in accordance with claim 1 or 2, characterized in that the signal-producing device is adjustable for emitting rise times of from approx. 0.1 s down to approx. 1 us.