CA1166318A - Body healing apparatus with pulse fed coils - Google Patents

Abstract

ABSTRACT

Disclosed is an electromagnetic body-treatment device for surgically non-invasive modification of the growth, repair and maintenance behavior of living tissues and cells by a specific and selective change in electrical environment. The device comprises two multi-turn electrical coils and body-adapting retaining means adapted to mount the coils in spaced relation on opposite sides of an afflicted body region to be treated.
The coils, when thus mounted, have turns about a flux-development axis through the afflicted body region and are connected in flux-aiding relation.
The turns are radially spaced from the axis to an extent establishing an effective local diameter which substantially equals or exceeds the effective axial spacing between said coils. The coils are electrically excited with a succession of low-voltage unidirectional asymmetrical pulses.

Description

3 ~ ~

This application is a divisional of copending Canadian Patent application serial No. 357,039 filed on July 25, 1980 in the name of Electro-Biology, Inc.
This invention relates to the treatment of living tissues and/or cells by altering their interaction with the charged species in their environment. In particular, the inven~ion relates to a controlled modification of cellular and/or tissue growth, repair and maintenance behavior by the application of encoded electrical information. Still more particularly, this invention provides for the application by a surgically non-invasive direct inductive coupling, of one or more elec~rical voltage and concomitant current signals conforming to a highly specific pattern.
Several attempts have been made in the past to elicit a response of living tissue to electrical signals.
Investigations have been conducted involving the use of direct current, alternating current, and pulsed signals of single and double polarity.
Invasive treatments involving the use of implanted electrodes have been followed, as well as non-invasive techniques utilizing electrostatic and electromagnetic fields. Much of the prior work that has been done is described in Volume 238 of the Annals of The New York Academy of Sciences published 11 October 1974 and entitled "Electrically Mediated Growth Mechanisms in Living Systems" (Editors A. R. Liboff and R. A. Rinaldi). See also "Augmentation of Bone Repair by Inductively Coupled Electromagnetic Fields" by C. Andrew L.
Bassett, Robert J. Pawluk and Arthur A. Pilla published in Volume 184, pages 575-577 of Science ~3 May 1974).
The invention herein is based upon basic cellular studies and 1 - r~

6 ~ 1 ~

analyses which involve a detailed consideration of the interactions of charged species, such as divalent cations and hormones at a cell's interfaces and junctions.
Basically, it has been established that, by changing the electrical and/or electrochemical environment of a living cell and/or tissue, a modification, often a beneficial therapeutic effect, of the growth, repair and maintenance behavior of said tissue and/or cells can be achieved. This modification or effect is carried out by subjecting the desired area of tissues and/or cells to a specifically encoded electrical voltage and concomitant current, whereby the interactions of charged species at the cells' surfaces are modified. Such modifications engender a change in the state or f~mction ~`
of the cell or tissue which may result in a beneficial influence on the treated site. For example, in the specific case of bone growth and repair, it is possible with one electrical code, hereinafter referred to as Mode 1, to change the interaction of the ion such as Ca2 with a cell's membranes.
Whereas, with another electrical code, hereinafter referred to as Mode 2, a modification in the same cell's protein-synthesis capabilities can be a:Efected.
For example, tissue-culture experiments involving the study o~
embryonic chick-limb rudiments show that the use of a Mode 1 code signal elicits enchanced Ca2 release of up to 50% from the competent osteogenic cell.
This effect is highly specific to the parameters of the electrical code of Mode 1. Thus, this code influences one major step of ossification, i.e., the mineralization of a bone-growth site. Similar tissue-culture studies using Mode 2 code signals have demonstrated that this code is responsible for enhanced protein production from similar competent osteogenic cells. This latter effect is also highly specific to the parameters of the electrical code . .~i, ~., .

., ' ~

1 1663 1 ~

of Mode 2. In other words, this code affects certain metabolic processes for these types of cells such as those involved in calcium uptake or release from mitochrondria as well as the syn~hesis of collagen, a basic structural protein of bone.
These studies show that the electrical codes of Mode 1 and Mode 2 elicit individual tissue and cellular responses, indicating that each code contains a highly specific informational content therein. Based upon these and other studies, it has been possible to utilize Mode 1 or Mode 2 signals or a particular combination of Mode 1 and Mode 2 signals to achieve a specific response required to enable the functional healing of a bone disorder. These electrical modes have been applied successfully to human and animal patients for non-healing fractures such as congenital pseudarthrosis and non-unions as well as fresh fractures. Successes achieved in the congenital pseudarthrosis cases are particularly noteworthy, since normally 80% oE children thus afflicted require amputation, since conventional treatments such as bone grafting and internal fixation are unsuccessful.
While there have been many investigations in the past of the response of living tissues and/or cells to 01ectrical signals, clinical results to date using prior techniques have not been uniformly successful or generally accepted withln the appropriate professional community. Several reasons con~ribute to this state. First, it has not been realized heretofore that electrical signals of very specific informational content are required to achieve a spejcifically desired beneficial clinical effect on tissue and/or cells. Second, most of the prior techniques utilize implanted electrodes, which by virtue of unavoidable faradaic ~electrolysis) effects are often more toxic than beneficial in the treated site. Furthermore, the cells and/or 3 :1 ~

tissues are subjected to a highly uncontrolled current and/or voltage d;stribution, thereby co~promising the ability of the cells to respond, should they do so, to the applied signal. This highly uncontrolled current and/or voltage distribution also applies in the case of capacitatively coupled signals.
In contrast, the surgically non-invasive direct inductive coupling of electrical i~formational content of specific electrical codes as involved in the present invention produces within living tissue and/or cells a controlled response.
In brief~ the present invention involves the recognition that the growth, repair and maintenance behavior of living tissues and/or cells can be modified beneficially by the application thereto of a specific electrical information. This is achieved by applying pulse waveforms of voltage and concomitant current of specific time~frequency-amplitude relations to tissue and/or cells by a surgically non-invasive means through use of a varying electromagnetic field which is incluctively coupled through direct induction into or upon the tissue and/or cells under treatment. The information furnished to the cells and/or tissues by these signals is designed to influence the behaviour of non-excitable cells such as those involved in tissue growth, repair, and maintenance. These growth, repair and maintenance phenomena are substantially different from those involved in excitable cellular activity (e.g., nerves, muscles, etc.)~ particularly with respect to the type of perturbation required. Thus, the voltages and concomitant currents impressed on the cells and/or tissues are at least three orders of magnitude lower than those required to effect cellular activities such as cardiac pacing, bladder control, etc.

11~631~

The invention and that of copending Canadian Patent application serial No.357,039 will now be described in greater detail with reference to the accompanying drawings, in which:
Figure 1 is a simplified view showing the treatment of a bone in accordance with the invention;
Figure 2 is a perspective view of the treatment unit shown in Figure l;
Figure 3 is a view ~from the rear) of the unit shown in Figure 2, showing the positioning of a coil therein used for treatment purposes;

Figure ~ is a block diagram of an electrical system for energizing the coil shown in Figure 3 for Mode 1 treatment;
Figure 5 is a block diagram of an electrical system for energizing the coil shown in Figure 3 for Mode 2 treatment;
Figures5a and 5b are pulse waveform diagrams for Mode 1 and Mode 2 treatments, respectively, showing presently preferred pulses as induced in living tissues and cells;
Figure 6 shows alternative forms of negative pulse portions for Mode 2 treatment;
Figure 7 is a front view of a body-treatment device, being an em~odiment in substitution for that of Figure 1, and shown unfolded, in readiness for wrapped application to an afflicted body region;
Figure 7A is a sectional view, taken at 7A-7A of Figure 7;
Figure 8 is a perspective view of a locating element for use with the device of Figure 7;
Figure 9 is a simplified schematic illustration of a method of use of the device and element of Figures 7 and 8;
Figure 10 is a simplified right-sectional view through a body-limb 3 ~ ~

cast to which the device and element of Figures 7 and 8 have been applied;
Figures 11 and 12 are simplified views in perspective showing further body-treatment devices, for particular purposes;
Figure 13 is a diagram to illuminate discussion of dual-coil placement considerations;
Figures 14, 15 and 16 are similar pairs of views a and _, respectively schematically representing front and side elevational views for each of three different generally elliptical dual-coil configurations; and Figures 17 to 20, appearing on the same drawing sheet as Figure 11, are views similar to Figures 11 and 12 to show coil arrangements for further body treatment devices.
DETAILED DESCRIPTION
Referring to Figures 1 to 3, the leg 10 of a person having a broken bone, as indicated as at 12, is shown as representative of the application of the invention to the stimulation of bone growth for healing purposes. A
treatment head 14 is positioned outside tha skin oE the person, and is held in place by use of a strap 16 (secured to head 14 by fasteners 16a) which may include ~elcro material 18 thereon so that the strap may be wrapped about the leg and about the treatment head to maintain the treatment head in position against the leg. The treatment head 14 may include a foam material 20 on the inside surface thereof for the purpose of cushioning and ventilating the treatment head against the leg. It will be noted ~hat the treatment head 14 is generally curved OII the anterior surface thereof so that it conforms to the shape of the leg under treatment The treatment head 14 includes therein a coil 22 which may be of any suitable shape. As shown in Figure 3 the coil 22 is generally rectangular * Trade Mark '.

1 ~i63 1 ~

in shape so as to define a "window" within the interior portion of the turns of the coil. The coil 22, may lie in a plane or it may generally be curved to conform to the curvature of the treatment head 14. The coil 22 includes terminals 24 which extend away from the treatment head 14 to be coupled to a cable 26 for connection to a suitable energizing circuit, as will be explained below in more detail. A diode 27 may be included within the cable 26 for connection across the coil 22 as will also be explained below.
The treatment head 14 is positioned on the patient so that the "window" formed by the coil 22 is adjacent the break 12, i.e., adjacent the tissue under treatment. The coil 22 is energized, as will be explained in more detail below, and induces an electrical potential within the tissue under treatment. It has been found that a particular type of signal should be induced within the tissue and this is achieved by energizing the coil 22 by a circuit, such as shown in Figure 4 or Figure 5, to produce the pulse signal shown in Figure Sa or Figure 5b.
Referring to Figure 4, a variable dc supply 30 is coupled through a gate 32 to the treatment coil 22 (or coilsJ as the case may be, and as will be explained in more detail below). ~he gate 32 is under the control of control units 34 and 36 which cause a pulse signal consisting of repe*itive pulses of electrical potential to be applied to the treatment coil 22. Each pulse, as shown in Figure 5a, is composed of a "positive" pulse portion Pl followed by "negative" pulse portion P2 because of the stored electrical energy within the treatment coil. In the circuit of Figure 4, a diode clamping unit 38 may be employed to limit the pea~ potential of that negative pulse portion. ~he diode clamping unit 38 may be one or more diodes connected across the coil 22, :iL16~3~ ~

and may be advantageously located within ~he cable 26. The diode 27 shown in Figure 1 constitutes such a clamping unit 38.
In Figure 5a, the signals at the treatment coil 22 and hence the induced signal within the tissue to be treated are shown. At time tl, it is assumed that gate 32 is gated on by an appropriate signal from control unit 36 ~designated a pulse width control unit) so that the electrical potential across the treatment coil 22 is raised from about zero volts along pulse segment 39 to a potential designated vl in Figure 5a. The signal across the treatment coil decays in a second pulse segment along the portion of the curve designated 4~ in Figure 5a. The slope of that curve is determined by the L/R
time constant of the circuit of Figure 4, i.e., the inductance of the treatment coil and the effective resistance of the circuit, including distributed factors of capacitance, inductance and resistance. For treatment of many tissues and cells~ it is believed desirable to adjust the circuit parameters so that the portion 40 of the curve is as flat as possible, rendering the signal applied to the treatment coil 22 as rectangular in shape as possible. At the time t2, the gate 32 is gated off by the control unit 36. Just prior to being gated off, the signal across the treatment coil is at the potential v2 shown in Figure 5a. The potential across the treatment coil drops from the level v2 in a third pulse segment 41 to a potential of opposite polarity designated v3 in Figure 5a. The magnitude of the opposite polarity potential v3 may be limited by the diode clamping unit 38 to a relatively small value as compared with value vl. The signal across the treatment coil 22 then decays from the potential level v3 to the zero or reference potential level, finally effectively reaching that level at time t3. A predetermined period passes ~ _ :

l~66~la before the pulse-repetition rate control unit 34 generates an appropriate timing signal to trigger the control unit 36 to generate a signal to turn gate 32 on again ~o continue the cycle just explained.
The control units may typically be monostable multi-vibrators, e.g., to generate appropriate timing signals and which may be variable to control pulse duration and repetition rate within desired limits. Further, the use of a variable dc supply 30 permits variation of the amplitude of the pulse signal as desired.
When pulse-train operation ~ode 2) is employed, additional timing circuitry similar to units 34 and 36 in Figure 4 is employed to provide the burst-segment width and the burst-segment repetition rate. Referring to Figure 5, control units 35 and 37 control gate 33 to produce a signal applied to coil~s) 22 of the wave form type as shown in Figure 5b. The circuit is otherwise the same as in Figure 4, except that the diode-clamping unit 38 is omitted to permit the large negative-pulse portions as shown in Figure 5b. The control unlts 35 and 37 determine the number of pulses in a burst and the time between successive bursts.
It has been found that the signal across the treatment coil 22, and hence the iDduced signal within the tissue under treatment, should satisfy certain criteria. These criteria will be specified with respect to the signal as _nduced in the tissue and/or cells under treatment. Such induced signal may be monitored, if desired, by use of an auxiliary monitoring pickup coil ~not shown) which is positioned at a distance from the treatment coil 22 corresponding to the distance of the tissue under treatment rom that coil, as will be explained in more detail below. In any event, it has been found that _ g _ :1~6~3~

the following criteria should be satisfied for effective treatment of living tissues and cells, in particular, hard tissue such as bone.
~ n the following presentation, the signals shown in Figures 5a and 5b constitute the pulses of electrical potential and concomitan* current generated by the coil and impressed upon the tissues and/or cells. These pulses have one polarity upon "energization" of the coil (termed herein the "positive" pulse portion and shown as the positive-going portion of the waveform on Figures 5a and Sb). These pulses have an opposite polarity upon "de-energiz-ation'l of the coil ~termed herein the "negative" pulse portion and shown as the negative-going portion of the waveforms of Figures 5a and 5b). The terms "positive" and "negative" are intended to be relative only, and are used herein only for the purpose of indicating that pulse portions of opposite polarity, with respect to a reference potential level, are involved.
It has been determined that the "positive" pulse portions should bear a predetermined rela~ionship to the "negative" pulse portions in order to modify beneficially and with uniform results the behavior of living tissues and cells. This pre determined relationship has been achieved by the utilization of two different signal modes, as well as combinations thereof.
In Mode l~see Figure 5a), the asymmetrical waveform induced in tissue or cells by the alternata energization and de-energization of arl electromagnetic coil is repeated at a frequency such that the overall duty cy~le is no less than about 2%. This frequency, in Mode 1, has typically been about,10-100 Hz with duty cycles of 20-30%. The basic relationship for Mode 1 of the respective frequency amplitude content of the "positive" and "negative"
pulse portions is as follows: pulse signal should be of a particular shape, namely, each "positive" pulse portion should be composed of at least three ? `

_ 10 -' :~ ~663~ ~

segments, e.g.,the segments 39, 40 and 41 in Figure 5a. As noted above, it has been found that a substantially rectangular shaped "positive" pulse signal portion is particularly useful in the treatment of tissue and cells. However, it is possible that other pulse configurations ~other than a simple two-segment spike) may be useful. The peak amplitude of the final segment of each "positive" pulse portion, e.g., the potential v2 in Figure 5a should be no less than about 25% of the peak amplitude of the first segment 39 of the "positive" pulse portion, e.g., the potential vl in Figure 5a.
The peak "negative" portion amplitude is denoted by v3 in Figure 5a.
This peak amplitude should be no more than about l/3 the peak amplitude of the "positive" pulse portion. The time duration of each "positive" pulse portion (the period that elapses between times tl and t2 in Figure 5a) should be no longer than about l/9 the time duration of the :Eollowing "negative" pulse portion (the time elapsing between times t2 and t3 in Figure 5a), Because the treatment system utilizes an electro-magnetic coil, the energy of each "positive" pulse portion is equal to the energy o:E each "negative" pulse portion, i.e., the area in Figure 5a embraced by the "positive" pulse portions is equal to ~he area embraced by the "negative" pulse portions. By satisfying the criteria just mentioned, the ~nergy of each "negative" pulse portion is dissipated over a relatively long period of time, and the average amplitùde of that negative pulse portion is limited. It has been found that such average negativé amplitude should be no greater than about l/6 the average amplitude o~
the "positive" pulse portion.
These relationships also ensure that the "positive" and "negative" pul-se portions haue the proper frequency-amplitude characteristics within themselves ~ ~fi63 ~ 8 and to each other such that a beneficial modification of the behavior of tissues and cells is accomplished.
Besides the relationships just mentioned~ it has been found that the average magnitude of the "positive" pulse portion peak potential should be within the range of about O.OOOl to O.Ol volt per centimeter of tissue or cells, corresponding to between about O.l and lO microampere per square centimeter of treated tissue and/or cells (based upon typical cell and tissue resistivities).
It has been found that higher or lower pulse potentials will not result in a beneficial effect. It has also been found that the duration of each "positive"
pulse portion(the time elapsed between times tl and t2 in Figure 5a) should be at least about 200 microseconds. If the time duration of each "positive"
pulse portion is less than about 200 microsecondsJ the tissues and cells are not stimulated sufficiently to modify the repair or other processes. From a practical standpoint, the "positive" pulse portion duration should not be greater than about l millisecond. It has also been found that the repetition rate of the pulses should be within the range oE about 65 to 75 Hz for bone and other hard tissues. Pulse treatments within this range have been found to be particularly effective with reproducible results for tissues and cells of this type. In general, however, pulse repetition rate should be between about lO and lO0 Hz for good results in tissues and cells.
For the treatment of bone disorders, and particularly for the treatment of pseudarthrosis, it has been found that for Mode l an optimum induced "positive" pulse signal portion having a peak amplitude of between about l and 3 millivolts per centimeter of treated tissue (l to 3 microamperes per square centimeter of treated tissue and/or cells~ with the duration of each "positive"

:~ `

13L6~3~ a pulse portion being about 30U microseconds and the duration of each of the "negative" pulse portions about 3300 microseconds~ and a pulse repetition rate of about 72 Hz, represents a presently preferred and optimum induced pulse treatment as long as the pulse-shape requirements noted above are met. Total treatment times may vary. It is presently believed that pulse-signal treatments for periods each lasting for at least about 15 minutes J with one or more periods of treatment during a prescribed number of days, may be effective in stimulating tissue and cell behavior. A preferred treatment regime using Mode l has been found to be a minimum of 8 hrs/day for a period of four months in difficult cases, and two weeks in less difficult cases.
In Mode 2 treatment (Figure 5b) the asymmetrical waveform induced in tissue or cells by the alternate energization and de-energization of an electromagnetic coil is applied in a pulse-train modality, which contains bursts (pulse groups) of as~nmetrical waveforms. Each burst of asymmetrical pulses has a duration such that the duty cycle of the burst portion is no less than about 1%. The burst frequency has typically been about from 5-50 ~1z.
The basic relationshipsfor Mode 2 of the respective frequency-amplitude content of the "positive" and "negative" pulses within the burst section of the pulse train are as follows: each "positive" pulse portion

2~ should be composed of at least three segments, e.g., the segments 39', 40' and 41' in Figure 5b. For this mode, it has also been found that a substantially rectangular shaped "positive" pulse-signal portion is particularly useful in the treatment of tissues and cells. However~ it is possible that pulse configurations other than a simple two segment spike may be useful. The peak amplitude of the final segment of each "positive" pulse portion, e.g , the potential v2 in Figure 5b, should be no less than about 25% of the peak amplltude of the first segment 39' of the "positive" pulse portion, e.g., the potential vl in Figure 5b.
The peak "negative" amplitude is denoted by V3 in Figure 5b.
This "negative" peak amplitude should be no more than about 40 times the "positive" peak amplitude (in this case vl). This requirement may be met by utilizing "negative" pulse portions having several different waveshape forms e.g., substantially rectangular, trapezoidal with exponential decay, bell-shaped, or single-spike with exponential decay, as in representative waveforms a, b, c and d in Figure 6.
The duration of each "positive" pulse portion (the time that elapses between times tl and t2 in Figure 5b) should be at least about 4 times the duration of the following "negative" pulse portion (the time that elapses between times t2 and t3 in Figure Sb). As noted above, since the treatment system utilizes an electromagnetic coil, the energy of each "positive" pulse portion is equal to the energy of each "negative" pulse portion, i.e., the area in Figure 5b embraced by the "posi~ive" pulse portions is equal to the area embraced by the "negative'' pulse portions.
The pulse-repetition rate of the pulses within the burst segment of the Mode 2 pulse train (the time elapsing between times tl and t4) can be between about 2000 Hz and 10,000 Hz.
The width of the burst segment o the pulse train (the time elapsed between tl and t5) should be at least about 1% of the time elapsed between tl and t6.
By satisfying the criteria just mentioned, these relationships also ensure that the "positive" and "negative" pulse portions have the proper ..~

3 1 8 frequency~amplitude characteristics within themselves and to each other such that a beneficial modification of the behavior of tissues and cells is accomplished.
Besides the relationships just mentioned, it has also been found that the average magnitude of the "positive" peak potential should be within the range of about 0.00001 to 0.01 volts per centimeter of tissues and/or cells (between about 0.01 and 10 microampere per square centimeter of treated tissue and/or cells).
It has been found that higher or lower pulse potentials will not result in a beneficial effect on tissues and/or cells. It has also been found that the duration of each "positive" pulse portion in the burst segment of the pulse train (i.e., the time elapsed between tl and t2 in Figure 5b) should be at least about 1000 microseconds. It has also been found that the repetition rate o~ the burst segment should be within the range of about 5-15 Hz for bone and other hard tissues.
Each negative-pulse portion within the burst segment of the pulse train should be of a duration no greater than about 50 microseconds and of an average amplitude no greater than about 50 mv/cm of treated tissue and/or cells (about 50 microamperes per square centimeter of treated tissue and/or cells).
For the treatment of bone disorders, and particularly for the treatment of pseudarthrosis and non-unions, it has been found that an optimum induced "positive" pulse signal ~ortion having a peak amplitude of between about 1 and 3 millivolts/centimeter of treated tissue (i.e.,l to 3 microamperes per square centimeter of treated tissue and/or cells), with the du~ation of each "positive" pulse portion being about 200 microseconds, and the duration of each of the "negative" pulse portions being about 30 microseconds, and a time ~ ~6631 ~

elapsed between times t3 and t~ of Figure 5b of lQ microseconds, and a pulse repetition rate of about 4000 H~, and a burst segment width of aoout 5 milliseconds, and a burst repetition rate of about 10 Hz, represents a presently preferred and optimum induced pulse treatment in bone for Mode 2, as long as the pulse requirements noted above are met.
It is also believed that a single asymmetrical pulse as described in the burst segment of Mode 2 can be employed at a repetition rate similar to that used in Mode 1 for beneficial modification of tissue growth and repair.
Treatment of living tissues and cells by the above methods herein3 in particular for hard tissue such as bone, has demonstrated an increased repair response and generally un;form results have been attained throughout all patient and animal treatments. Particularly beneficial results have been obtained in the cases of treatment of pseudarthrosis in which a bone union has been achieved following previous unsuccessful attempts by other treatment methods and in which amputation has been discussed as a possible alternative to regain function.
In practice, it is believed desirable to utili~e as large a coil "window" as possible and to position the coil such that an adequate flux density is impressed upon the tissue and/or cells being treated. As is known, a time-varying magnetic-field induces a time-varying voltage field orthogonal to it. That is, the geometry of the magnetic-field lines determin~ the geometry of the induced-voltage field. Because a relatively uniform induced-voltage field is desired, the geometry of the magnetic-field lines should be as uniform as possible, which may be achieved by rendering the si~e of the coil relatively large with respect to the area under treatment. At this particular time, it is not believed that there need be a particular orientation between ~ ~ 6 ~t~l ~

the magnetic-field lines and the tissue and/or cells being treated.
It is believed that the uniformity of the induced-voltage field possible through electromagnetic treatment is responsible in many respects for the good treatment results which have been obtained, in distinction to the non-uniform fields which may and probably do result with other types of treatments, for example utilizing electrostatic fields or by the creation of a potential gradient through the use of electrodes implanted within or on tissues or cells. In particular, an induced voltage field is present in a vacuum as well as in a conducting medium or an insulator. The field characteristics will in general be the same (within one percent) in these three cases, except in the case for which an induced current flow is sufficiently great to create a back electromotive force to distort the magnetic field lines.
This condition occurs when the conducting medium has a high conductivityJ
e~g., a metal, and is large enough to intercept a substantial number of magnetic-field lines. Living systems, i.e., tissue and/or cells, are much less of a conductor than a typical metal ~generally by at least 105, i.e.
five orders of magnitude). Because of these considerations, the geometry of the magnetic field present in tissue and/or cells is undisturbed and remains unchanged as the tissue and/or cell growth process continues. Thus, with non-invasive electromagnetic treatment, it is believed that the potentialgradient that is produced within the tissue and/or cells is constant regardless of the stage or condition of the treatment.
Such uniformity of induced potential is virtually impossible to be achieved through the use of implanted electrodes or by electrostatic coupling or by a transformer coupled to electrodes, or by implanted coils coupled to electrodes. Since these latter types of treatments are dependent upon ,. ` ' ~16~31~

conductivity, which will vary within tissue and/or cells, the induced potential gradient will not be constant as the condition of the tissue and/or cells changes. Additionally, at any particular time within tissue and/or cells, individual localities of the material being treated will have different conductivity characteristics, which will result in differing potential gradients throughout the material treated.
For these reasons, it is believed that a surgically non-invasive electromagnetic treatment of tissue and/or cells is greatly preferable to electrical treatment by other means.
Regarding typical coil parameters, it is believed that for typical bone breaks, coil windows of about 2.0" x 2.75" ~for an adult) and 2" x 1.5"
(for a child) are suitable. The wire employed in the coils may be B~S gauge 12 copper wire that is varnish-coated to insulate the turns one from another.
Coils of about 60 turns for an adult and 70 turns for a child seem to be suitable. For treatments in the oral cavity, coil sizes would be correspondingly smaller.
It is believed that the inductance of the treatment coil should be between about 1-5000 microhenriesJ and preferably between about 1000 and 3000 microhenries, with sufficiently low resistance ~e.g., 10 2 to 1 oh~) and a high input coil driving signal between about 2 and 30 volts, to induce the appropriate pulse potential in the tissue and/or cells treated. The lesser the inductance of the treatment coil, the steeper the slope of the curves 40 and ~0' as shown in Figures 5a and 5b; the greater the inductance, the flatter or more rectangular is the "positive" pulse that is produced.
The monitoring of the induced potential may be by actual electrodes making contact with the tissue and/or cells being treated or by use 3 1 ~

of a pickup coil positioned adjacent to the treatment coil 22 at a distance corresponding to the distance of the material under treatment from the coil.
A typical pickup coil that has been employed is circular, about one-half centimeter in diameter, with about 67 to 68 turns of wire. The potential developed by the coil is divided by the length of the wire (in centimeters) to provide an induced voltage per centimeter number that is closely related to the volts per centimeter induced in the tissue and/or cells under treatment.
A typical treatment utilizing a coil having a "window" 2" x 2.75"
and 60 turns of number 17 gauge wire J including a diode at the coil such as the diode 27 in Figure 1, produced the following induced voltages in a pickup coil*
for the pulse times~in microseconds) as follows (voltages and times are with reference to ! the waveform of Figure 5):
Induced Voltagevl v2 v3 tl-t2 t2-t3 Maximum ~at face of treatment coil) 22 17 3.7 300 4200 5/8" from Eace of treatm~nt coil 15 11.5 2.5 300 ~200 1 1/2" from face of treatment coil ; 6.0 4.2 1.0 300 ~200 The use of pulsing electromagnetic fields to control bone formation in a variety of conditions, now, is on a sound experimental and clinical basis.
Thus far, the developments have had application in treating successfully congenital and acquired pseudarthrosis and fresh fractures in humans, increasing _ * These voltage values may be translated into millivolts per centimeter of tissue, by dividing by a factor of substantially ten~

116~

the rate of fracture and reactive periostitis repair in animals, and reducing bone loss in disuse osteoporosis of long bones. Success with the method hinges on the discovery of pulse patterns with specific time-frequency-amplitude relationships as outlined above.
EXAMPLES
In order to demonstrate efficacy, the utilization o~ direc-t i~dUcti~e coupling of electromagnetically induced pulsing voltages and concomitant current via Modes 1 and 2 and combinations thereof for hard tissue growth and repair was initially applied in cases of congenital and acquired pseudarthrosis, In a group of patients, only individuals who had been treated previously by one or more unsuccessful surgical attempts (grafting, internal fixation~ were accepted. For most of these patients, amputation had been recommended by at least one qualified orthopedist. Throughout this study, the necessity for pulse specificity was illustrated again and again. For example, when lack of ossification was the primary problem (usually the case for congenital pseudarthrosis), Mode 1 treatment was utilized with final functional bony union occurring only when the parameters of the pulse corresponded to those given above. On the other hand, when lack of bony matrix was the primary problem, Mode 2 treatment was employed in order to achieve the production of collagen which is the primary supporting protein in bone structure. ~ince protein production and ossification are two completely different steps in bone formation, the highly selective nature of each of the signals utilized in Modes 1 and 2 could be synergistically combined when neither matrix production nor ossification were present in a given patient's treatment history. Thus~ a combination of Modes 1 and 2 was utilized with benefit in this type of situation.

~ ~63:~ ~

In the case of congenital pseudarthrosis, the typical patient is ~etween one and ten years of age. The afflicted part is normally the distal tibia of one extremity. The patients were presented with an average of three prior unsuccessful surgical procedures and had the condition for an average of 5 years, and all were candidates for amputation.
The treatment of such a patient was normally carried out using Mode 1 treatment regime since the primary problem was due to a lack of ossification in the affected area.
The patient is prescribed the appropriate equipment by the attending orthopedic surgeon and carries out his treatment on an out-patient basis. Treatment time is typically 12 to 16 hours a day for about an average of 4 months.
Some 20 of this type of disorder have been treated to date with successful ossification achieved in approximately 90% of the treated individuals.
For acquired pseudarthrosis, either traumatic or operative, patients are mostly adults and had an average number of three failed operations and an average of 2.5 years from onset of non-union. Amputation had been discussed for seventy percent of these individuals. Since in some cases the primary problem was lack of bony matrix, typically visible radiographically as gaps in the bone of more than 2 mm in the fracture site, such a patient was treated commencing with Mode 2 modality. When it was thought that sufficient non-ossified bony matrix was present Mode 1 modality was employed to gain rapid immobilization of the fracture site.
Because of the particular pathology of several patients in this group, a combination of Modes 1 and 2 was employed with this treatment being ~L 16~;3 :1 ~

specifically Mode 2 followed by Mode 1. As in the case of congenital pseudarthrosis, the proper equipment was prescribed by the attending orthopedic surgeon and treatment was performed on an out-patient basis, Treatment time is typically 10 - 14 hours/day for periods ranging from 3 to 9 months.
Some 30 of this type of disorder have been treated to date with successful bony union observed in 75% of the treated individuals.
These clinical results clearly demonstrate that once the particular pathology of a bone disorder is diagnosed it can be selectively beneficially treated by the application of properly encoded changes in electrical environment.
Similar findings have been obtained from a study of bilateral femoral and radial osteotomies in 160 rats. These animals were divided into two major groups; field exposed and control for an interval of 1~ days after operation. Following sacrifice, the extent of fracture repair was judged on the basis of X-ray and histologic evaluation, coupled with non-destructive mechanical testing. These animal models were employed to evaluate the effectiveness o~ treatment modalities of Modes 1 and 2 and combinations thereof. Generally, when the osteotomy gap was less than 1.0 mm, a Mode 1 signal was effective since very little bony matrix was required for solidification. On the other hand, for wider osteotomies, substantially increased matrix production was observed over control animals when Mode 2 was employed. A combination of Modes 1 and 2 was employed in the latter case to obtain a stiffer repair site for an equivalent treatment time.
This was further evaluated by ~he response of these bones to mechanical testing This was performed by subjecting the bone of the rats 1 ~S~l ~

following sacrifice to cantilever loading at various deformations in accordance with the testing procedures described in "Acceleration of Fracture Repair hy Electromagnetic Fields. A Surgically Non-invasive Method" by C. A. L. Bassett, R.J. Pawluk and A. A. Pilla, published on pp. 242-262 of the Annals of The New York Academy of Sciences referenced ahove. The specimens were deformed in the antero-posterior, lateral-medial, postero-anterior, medial-lateral and again the antero-posterior positions.
The average response of a femur to this test at a deformation of 0.05 inch is shown in Table I as follows:
Table I

Mechanical Load Values In Electrical Stimulation of Artificial Osteotomies In Adult Female Rat Femur Load at 0.05 in.
Stimulation Defo:rmation Control ~untre~ted) 42 gms. ~ 5.2 gms.
Mode 1 Signal ~Figure 5a) 580 gms. ~ 65 gms.
In addition to radiographic and mechanical evidence of the effectiveness of the signal employed, histologic evidence further attests to this effectiveness.
Hemotoxylin and eosin stained longitudinal specimens show a much higher degree of maturation for the Mode l signal than in the control case.
For wider osteotomy gaps~ treatment times of fourteen days showed that the active animals had a significantly larger callus than controls.
Histologic evidence shows that the increase is at least 150% over controls.
Limited tooth extraction studies have been performed and show that pulses of the Mode 1 type may have a highly beneficial effect on the rate of ' . ' 1 ~663 1 ~

healing and on bone loss in the oral cavity. The latter effect in the oral cavity is particularly important for the maintenance of mandibular and maxillar crestal bone height, a very important factor for implant fixation.
These observations all point to the fact that electromagnetic fields with highly specific pulse characteristics can be non-invasively inductively coupled to biological systems to control cell behavior. In the initial application of these principles, effects on bone cells have been investigated~ Other biological processes, however, may eventually be proven to be controlled by similar techniques, e.g., malignancy, neuro-repair, inflammatory processes and immune response, among others.
In summary, it is believed that a unique electromagnetic and surgically non-invasive treatment technique has been discovered. Induced pulse characteristics appear to be highly significant, especially those relating to the time-frequency-amplitude relationships of the entire pulse ~or pulse sequence. It is believed that selection of particular time-frequency-amplitude relationships may be the key to successful treatments of varying cellular behavior in a variety of tissues.
Throughout the specification for Mode 1, a preferred pulse repetition rate of between about 65 and 75 Hertz had been specified for bone and other hard tissue, The exact limits of the pulse-repetition rate are not known for all types of tissues and cells. It is believed that preferred operating ranges will vary depend mg on the tissue and cell type. Positive results have been obtained, for example, in soft-tissue treatment at 20 Hertz.
It will be appreciated ~hat the methods and apparatus described above are suscepti~le of modification. For example, while Figures 1 and 2 illustrate a treatment unit which may be strapped to the leg, treatment units incorporated in casts, e.g., may be employed. Further, treatment may be carried out by use of one or more coils of varying shapes positioned adjacent to tissue and/or cells to be treated. In fact, some treatments of humans have involved coils positioned upon opposite sides of a bone break. Coils with metal cores may also be used. In the case of treatment within the oral cavity, it is believed that double coils are advantageous, positioned, for example, on opposite sides of a tooth socket to stimulate repair of that socket. Some specifically beneficial treatment units and procedures will be described in connection with ~igures 7 to 16.

Figures 7 and 7A illustrate a body-treatment or applicator device which is most beneficially applied to the treatment of bone breaks or non-unions in arm or leg members, i.e., wherein the bone region to be treated is relatively elongate. The device comprises two coil-mounting units 50-51 each of which contains an electrical coil of the character already described, and they are flexibly interconnected to permit ready adaptability to opposite sides of the region to be treated. Each of the units 50 - 51 may be of like construction, essentially involv:ing a rigid potting o:E its coil turns in a consolidating mass of cured elastomeric or plastic material; however, in the preferred form, each unit, such as unit 50, comprises a casing consisting of flanged concave-front and convex-back panels 52-53, with the peripheral flange 54 of front panel 52 in continuous telescoping overlap to the similar flange 55 of back panel 53.
Registering and abutting inwardly projecting boss or foot formations in pa~els 52-53, as at 56, enable the two panels to be bolted together in the precisely spaced relation shown in Figure 7A. The respective inner and outer panels of unit 51 are precisely the same as for unit 50, except that as a further feature of the invention a rectangular recess 57 is inwardly formed in panel 52, for a , ' ' locating or key purpose to be later explained. The secured boss or foot formations at 56 are preferably offset inwardly from the flanged peripheries of panels 52 - 53, thereby defining peripherally spaced means for locating the inner limit of turns of coil 58 within the flange 55 of back panel 53. The coil turns may be rigidly bonded in place, to and within flange 55, or they may be adequately retained by compressible material such as urethane foam, compressed as the bolted connections are established at 56.
The flexible interconnection of units 50 - 51 is shown to include an electrical cable 59 for establishing the electrically parallel inter-connection of like coils 58 in the respective units 50 - 51, the polarity of such interconnection being such that magnetic-flux lines within the two coils 58 and in the space therebetween are flux-aiding when the front ~concave) panels of units 50 - 51 are in face-to-face relation. Removable connection of the coils 58 to the energizing circuitry of E~igures ~ or 5 is shown by way of the single plug and socket means 24 - 26, via unit 51. Typically,each of the two coils 58 has an inductance in the order of 5000 microhenries, so that in their preferred parallel relation the inductance presented to the output of the applicable one of the circuits of Figures ~ and 5 is 2500 n~icrohenries.
The flexible interconnection of units 50 - 51 also includes articulating strap means, as of Velcro material, to enable simple adaptation to the dimensional requirements of each patient's particular circumstances.
Thus, uni~ S0 is shown with a first such strap element 60 secured to its back panel 53 and having a free end extending a distance Ll to one lateral side of uni~ 50; similarly, unit 51 is shown with another str~p element fixed to its back panel and having a first free end 61 of length Ll extending laterally for adjustable overlapping connection to the free end of strap 60. The opposite ~ 26 ~

ll663~a end 62 of the strap carried by unit 51 is also free but of substantially greater length L2, to permit full circumferential completion of the strap co~mection as the means of removably applying both units 50 - 51 to the body-member treatment region; preferably, the length L2 is sufficient to enable the ~elcro-material region 63 at the inner or front face of the free end 62 to circumferentially envelop the body member and to enable region 63 to have removable Velcro engagement with~a suitably equipped back surface of the same strap member, as at the region of its fixed mounting to the back panel of unit 51.
The coils 58 are shown to be of generally elliptical configuration.
These coils should be of sufficiently large internal dimensions, in relation to their ultimately installed positioning for bone treatment, as to assure relatively uniformly distributed concentrated flux within the treatment zone.
Elementary principles and preferred dimensional relationships for a two-coil flux-aiding circular configuration will be ]ater discussed, with a view to minimizing the establishment of stray-flux lines between the two coils. It suffices here to point out that by employing ~he cylindrically concave-convex configurations described for panels 52-53, the coils 5~ are necessarily also conormed to a geometrical shape which is cylindrically arcuate, the major-axis direction of the ellipse being parallel to the axis about which each coil 5~ is cylindrically arcuate. Thus, when units 50~51 are positioned for body treatment, the concave sides o both coils 58 are in face-to-face relation, with the minor-axis spaced coil regions m~_ of unit 50 in closer adjacency to the corresponding minor-axis spaced coil regions m'-_'of unit 50 than is the case for coil-to-coil spacing of corresponding major~axis spaced coil regions ~-~ and ~ '; as a result of this relation, any tendency to establish . . ~ '' , ' ~ .
.

stray-flux lines between corresponding minor-axi.s coil regions m-n' and _'-n is minimized.
Specific use of the body-treatment device of Figures 7 and 7A
will be more clearly understood through additional reference to Figures 9 and 10, utilizing a locating-block or keying device (shown in Figure 8) which may be expendable and of suitable molded plastic such as polypropylene. The locating device of Figure 8 comprises a rectangular-prismatic block 65 which is dimensioned for removable locating reception in the rectangular recess formation 57 that is cen*ral to the concave panel 52 of unit 50. Integrally formed with and extending in opposite longitudinal directions from the base of prism 65 are elongate mounting strips 66 which are relatively stiffly compliant for slight bending adaption to particular body or cast configurations. Also, the thickness and material of strips 66 should be such as to permit sheared cut off to shorter length, as may be needed for some applications. A
pressure-sensitive tape 67, which may incorporate metal foil, wire or other material opaque to radiological irradiation i.s shown to be removably adhered to the peripheral edge of block 65.
In the initial s~ages of use of the device of Figure 7, i.e., during the period in which the separate halves o~ a bone break or non-union are to be fixedly retained for electromagnetically induced treatment of the invention, the afflicted limb, for example, the leg 70 of ligure 9, is first placed in a cast 71 which overlaps the afflicted region. The leg is then placed on a table 72 so that the afflicted region can be viewed under radiological irradiation, schematically designated by an arrow, with the legend "X~Rays", instantaneous and current viewing being provided by suitable video-scanning and display means 73-7~. The device of Figure 8 is then placed.upon .. ' ~

~1~63~

a local region of the cast 71 such that the opaque periphery of prism 65 is viewable at 74 as a rectangular frame, surrounding the central zone of the bone break or non-union region to be treated. ~hen the opaque frame is seen in the display in proper surrounding registry with the afflicted bone region, i.e., after such positioning adjustments as may be needed to assure such registry, the strip ends 66 are fastened to the cast 71, as by maans of adhesive tape suggested at 68. The cast 71 may then be further developed over the strip ends 66 to assure permanence of the locating prism as a fixed part of cast 71.
~len prism 65 is thus fixed to cast 71, strip 67 may be removed and discarded, and the patient is ready for the device, of Figure 7, which is assembled by first locating (i.e., keying) unit 50 via recess 57 to the prism 65, by then adjusting the ~elcro overlap 60-61 to position unit 51 in diametrically opposite relation to unit 50 (on the other side of cast 71), and by then using the s*rap end 62 for completion and securing of the circumferential overlap described for the inner-surface region 63. The electrical connection is then completed at 2~-26, and treatment may commence in the manner already described. It should be noted thatJ if the surface of the concave panel of each unit 50-51 is not soft-textured, there may be a tendency to generate chalk dust upon local mechanical fretting of the cast 71~ with repeated assembly and disassembly of units 50-51 theretoJ Such fretting can be minimized by adhering a foamed-plastic or the like yieldable liner to the concave panel of one or both units 5O-51J such a liner being shown at 75 in Figure 10. Still furtherJ the use of a foamed-plastic liner will assure greater patient comfort while frictionally contributing to stable placement and retention of the treatment coils.
Figure 11 depicts a body-treatment device which is particularly : ~ .' ' ~ ' . , . ' ' . ' ' . . ~ :

suited to the treatment of bone affliction in the region of the heel. For simplici~y in Figure 11, the showing is limited to relatively rigid structural components, and the foamed-plastic lining carried by such structure for patient comfort ~i.e., to avoid chafing~ has been omitted. Basically, the rigid structure of Figure 11 comprises a tubular shell 80, as of methylmethacrylate, being open at its longitudinal ends and locally open at 81, over an angular span ~about the shell axis~ and intermediate the longitudinal ends of shell 80.
An "S"-shaped strap 82, which may be of the same material as shell 80, has its upper end secured at 83 to the back end of shell 80, at opening 81, and its lower end 84 extends along the diametrically opposite region of the inner surface of shell80,todefine a plate for basic support of the bottom of a foot 85, to be inserted via the opening 81. The respective courses of two arcuately curved elliptical coils 86-86' are schematically indicated by heavy dashed lines. These coils will be understoocl to be bonded to shell 80 in vertically opposed relation, the upper coil 86 being bonded to the inner surface of shell 80J just inside the edge of opening 81, and the lower coil 86' being similarly bonded at the diametrically opposite location. Coils 86-86' thus have a permanent relation to each other, much the same as described for the coils 58 of units 50-51, once the latter are in body-assembled relation;
alld it will be understood that coils 86-86' are preferably electrically connected in parallel, in flux aiding polarity, being excited by one or the other of the energizing circuits of Figures 4 and 5.
In addition to the described coil-positioning and foot-supporting structure, the device of Figure 11 includes side-bumper guards 87-88 which may be bowed strips of the same plastic material as shell 80, suitably bonded at both ends to the respective longitudinal ends of shell 80. Strips 87-88 are ~ 30 _ ~63la preferahly stiffly yieldable, to cushion the treated region from mechanical shock in the event of unwitting contact with furniture or other objects.
Figure 12 is a simplified diagram similar to Figure 11 to illustrate another another body-treatment device, configurated for application to an afflicted ankle region, or to a lower tibia/femur region. Again, the basic rigid structure is seen to comprise a tubular shell 90, as of suitable plastic.
A single local side-wall opening 91 in shell 90 has a straight lower edge, contiguous to a bottom plate or rest 92 which diametrically spans the lower end of shell 90. Opposed electrical coils 93-94 are bonded to the inner surface of shell 90 at an elevation such that the alignment 95 of their centers of symmetry will geometrically intersect the cen~er of the afflicted region, preferably as confirmed by X-ray observation on the alignment 95.
The configuration of coils 93-9~ may be circular or elliptical, but is preferably cylindrically arcuate, in conformance with the local shell surface to which each of them is bonded; in the event of elliptical coil configurations, the major-axis orientation is preferably vertical, consistent with the discussion above as to coils 58 in Figure 7. Interconnection and excitation of coils 93-94 is as descrlbed for other two-coil devices.
It will be seen that the described devices and techniques represent major advances in surgically non-invasive treatment of body cells, particularly as they may be involved in bone repair and healing. With respect to the body-treatment~devices which have been described, we have not yet established the full range of dimensional limitations, but certain beneficial ranges can be described in general terms, particularly for dual-coil embodiments 9 illustratively disclosed in connection with Figures 7 to 12.
On an elemental basis, it is convenient to consider the circular-.;

.. . . . .

3 ~ ~

coil situation depicted in Figure 13, wherein like circular coils A-B of inside diameter Dl are positioned on a common central axis of symmetry, at parallel planes which are spaced apart by the distance S, and wherein the coils A-B are excited in :Elux-aiding relation If the spacing S is sufficiently small in relation to the diameter Dl, then substantially all flux lines within coils A-B will extend continuously therebetween, on a generally straight alignmen~ which may even neck down as suggested by the profile 96. If the spacing S is greater ~again in relation to the diameter Dl), some stray-flux lines 97 will develop, to the detriment of the development of uniform high-density flux in the central span S. Generally, in view of the necking down(96), and in view of the treatment zone being generally at the center of span S, it is convenient to consider the coils A-B as being desirably effective in producing the uniform flux distribution over an imaginary cylinder 98 of diameter D2, tangent to the neck-down profile 96. From our experience to date, we can state that for body application of the character presently described, the span S should be equal to or less than the diameter Dl, and of course D2 ~the effective diameter of the zone of body treatment) will always be considerably less than Dl, being substantially equal to Dl onl~ when coils A-B
are closely adjacent. As a practical consideration in the application of dual coils to the body, we consider that the nominal inside diameter Dl of the coils should be at least 1.5 times the diameter D2 of the effective body-treatment zone, and this has been found to be a reliable approach for coil spacing S substantially equal to the inside diameter Dl.
Having thus considered criteria factors for the simplified case of flat circular coils, it is possible to develop general criteria applicable to elliptical coils which are "hrapped" in general conformance with a ~ . .
- 32 _ 116~3~

cylindrical arc. Figure 14 schematically depicts the coil-58 relationship discussed for Figure 7, wherein the cylindrical arc of "wrapped" coil curvature is about a central axis 100, which is parallel to the major axis of the coil ellipse. And Figure 15 schematically depicts a coil-58' relationship wherein the cylindrically arcuate curvature of the coils is parallel to the minor axis of each coil. In both cases, the typical resultant treatment-zone section is suggested by dashed outline in the front view (Figure 14a and Figure lSa).
For purposes of deducing central magnetic-field distribution between opposed coils 58, their major-axis regions ~designated p-q-p'-q' in Figure 7) may be deemed to be at maximum separation Sl and their minor-axis regions (designated m-n-m'-n' in Figure 7) may be deemed to be at minimum separation S2, as viewed in Figure 14b. This being the case, major-axis-region contributions to the magnetic field may be deemed to apply for the span S ~of Figure 13) e~ual to Sl(of Figure 14b) in the context of an effective inside diameter Dmaj which corresponds to the major axis of the ellipse; by the same token, minor-axis-~region contributions to the magnetic field may be deemed to apply for a span S2 (of Figure 15b) in the context of an effective inside diameter ~min which corresponds to the minor axis of the ellipse. For sectional considerations at planes intermediate those o the major axes and of the minor axes, the field will follow distribution considerations intermediate those controlling distribution in planes of the major axes and of the minor axes, respectively.
Reasoning applied above as to magnetic-ield distribution for the Figure 14 configuration can also be applied to that of Figure 15, except of course that patterns will differ by reason of the cylindrical curvature about .j ~

~ ~63~ ~

an axis parallel to the minor elliptical axis.
The arrangement of Figure 16 depicts use of two generally cylindrically arcuate coils 58" wherein the cylindrical arcs are nested in spaced relation appropriate to the desired application, electrical connection being again understood to be for flux-aiding. The coil arrangement of Figure 16 will be understood to have application over a generally cylindrically arcuate treatment zone, as in the case of a jaw segment or group of teeth, the latter being suggested schematically at 101 in Figure 16b. Depending upon the size of coils 58", it will be understood that they may be retained in fixed spacing, using a suitable bracket (suggested at 102) which bridges only teeth in the case of insertion of both coils in the mouth, and which bridges teeth as well as the adjacent cheek (via the mouth) in the case of one coil inside and the other coil outside the mouth. It will also be understood that for purposes of certain desired flux distribution within the mouth, as for dental and/or jaw osteogenesis, the inner coil 58" may be of smaller physical size than the outer coil 58".
It will be understood that the foregoing discussion of general principles is with a view to illustration and not limitation,and that modif1cations may be made without departing from the scope of the invention.

For example, if for certain purposes, it is not possible to construct both coils of a dual-coil embodiment so as to completely match in geometry and electrical properties, as suggested above for a dental or jaw application, t~ere can still be a useful employment of the invention, using magnetic-flux distribution which may not be as uniform asjdiscussed in connection with Figures 13 to 16, but which nevertheless derives benefit from the flux-aiding cooperation of two coils in opposite sides of the afflicted region - 3~ -3 1 ~

under treatment, such benefit flowing of course from the excitation of such co~ls hy the specially characteri~ed inputs discussed in connection with FIgures 4 to 6.
Figures 17 to 20 are concerned with coil configurations applicable to flux development along and therefore generally parallel to the longitudinal direction of a body member to be treated. In Figure 17, a single coil of like plural turns 105 is helically developed along the length of a supporting tubular member 106 of suitable plastic or other non-magnetic material. The turns 105 may be on the inner or the outer surface of tube 106, and the axial length of the winding should be such as to overlap both longitudinal ends of the bone fracture or the like to be treated.
In Figure 18, a single winding is again shown carried by one of the cylindrical surfaces of a tubular member 108~ but the latter is locally cut at an opening 109 (as in the manner described at 81 in Figure 11~ to permit insertion of a joint region such as the elbow, with the forearm projecting out one axial end of tubular member 108, and wi~h the upper arm projecting radially outward via opening 109. The single winding is shown as a first plurality 110 of helical turns continuously connected by an axially expanded turn 111 to a second plurality 112 of similar turns, the pluralities 110-112 being positioned on opposite longitudinal sides of the opening 109 and at a spacing which is at least no greater than the effective diameter of the turns 110-112.
The arrangement of Figure 19 is similar to that of Figure 18 except that the respective pluralities of turns 110-112 are electrically connected in parallel, in flux-aiding relation. A central access port will be understood to be provided in tubular member 108 at a location opposite the ,.
~ 35 ~

,.. .
:

opening 109~ to permit excitation wiring connections to be provided external to all turns~ i.e.) no supply lines passing within any of the turns at 110~112.
In the arrangement of Figure 20, two coil subassemblies 115-116 are constructed for assembly to the respective ends of a longitudinally split compliant-supporting member 117 of non-magnetic material. The longitudinal split at 118 permits a degree of flexibility in application to a body member, as for example during the course of its assembly past the heel region to a leg part to be treated. Each of the coil subassemblies is shown to be a relatively rigid annular assembly of a winding to a potting of cured hardenable material, and formed with a counterbore 119 at which the coil subassembly is telescopically assembled over the end of the adjacent end of tubular member 117. The inner end of each counterbore defines an inward flange to limit coil assembly, and to determine repeatably accurate spaced retention of the two coil subassemblies.~ Electricàl connections to the coil subassemblies are shown to be parallel, and should be in flux-aiding relation, and a flexible-cable interconnection is suggested at 120.
It will be understood that various simplifying techniques have been adopted to make for more readily understood reference to the drawings.
For example, in the rigid-frame coil-supporting embodiments of Figures 11, 12, and~l7 to 20, it will be ~understood that in application to the body certain cushioning liner materials such as urethane foam are preferably adhered to the descrlbed structure for comfortable engagement with the body at the region of application, but to have shown such liners would only encumber the drawings. Also, in connection with Figure 9, the showing of the cast 71 is merely illustrative, in that the key device 65 may be otherwise v ~ .
.. ..
- 3~ -- ~ , , ~:

3 1 ~

externall~ mounted~ as for exam~le to an external fixation device such as a puttee~ or to the body limb itself ~i.e., without a cast, as in latter stages o~ a bone repair), and the cast may ~e of materials other than plaster, e.g., the material known as orthoplast.

J ~ 37 -

Claims (12)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. An electromagnetic body-treatment coil assembly, comprising a coil winding having a plurality of turns of large effective radius and short axial extent, and a relatively thin two-part housing for said winding, said housing comprising peripherally flanged front and back panel members assembled in registration with their flanged peripheries in telescoped relation, all turns of said winding being supported and confined at the telescoped peripheral region of and within said housing , said front panel member being concave and generally cylindrically arcuate, and said back panel member being convex with generally the cylindrically arcuate curvature of said front panel member, said winding and said peripheries conforming to substantially the same course and said flanges receiving and locating said winding.

2. The coil assembly of claim 1, in which said coil winding is of generally elliptical course, and said panels are arcuate about an axis that is substantially parallel to the major-axis direction of the winding ellipse.

3. The coil assembly of claim 1, in which said front panel has a central inwardly-cupped prismatic recess formation for removable reception of a body-mounted locating key, said recess formation being symmetrically positioned with respect to the central axis of said coil winding.

4. An electromagnetic body-treatment device for surgically non invasive modification of the growth, repair and maintenance behavior of living tissues and cells by a specific and selective change in electrical environment J
comprising magnetic-circuit means including two spaced elements and body-adapt-ing retaining means adapted to mount said elements in spaced relation on opposite sides of an afflicted body region to be treated, said elements being adapted when thus mounted to establish a flux-development axis therebetween and through the afflicted body region, and electric-circuit means for exciting said magnetic-circuit means with a succession of low-voltage unidirectional asymmetrical pulses, the effective sectional area of said elements being such in relation to the spacing of said elements when thus mounted as to enable establishment of a substantially uniform flux distribution throughout a major fraction of the geometrical volume defined by and between said elements.

5. An electromagnetic body-treatment device for surgically non-invasive modification of the growth, repair and maintenance behavior of living tissues and cells by a specific and selective change in electrical environment, comprising a multi-turn electrical coil and body-adapting retaining means adapted to mount said coil in external adjacency to an afflicted body region to be treated, said coil when thus mounted having turns about a flux-development axis to be aligned through the afflicted body region, said retaining means including a prismatic casing of non-magnetic material, said casing having a front surface adapted for orientation in facing adjacency to one side of the body region to be treated, said coil being located by and within said casing and in adjacency to said front surface, said surface having a locating key formation therein in symmetrical placement with respect to the central axis of said coil, and a removably positionable locating element having a surface formation which conforms to and is inter-engageable with said key formation, said locating element having laterally extending adapter means for relatively fixed location of said locating element with respect to the body to be treated, whereby once correctly located and fixed with respect to the body, said locating element will accurately determine the location of said coil upon assembly of said key formation thereto, so that said retaining means can then correctly reference said coil to the body-treatment region, for repeated application and removal of said coil with respect to the body.

6. The treatment device of claim 5, in which said locating key formation is a keying recess in said front surface, and in which the surface formation of said locating element is a key that is removably enterable in said recess.

7. An electromagnetic body-treatment device for surgically non-invasive modification of the growth, repair and maintenance behavior of living tissues and cells by a specific and selective change in electrical environment, comprising a single electrical coil having a plurality of turns generally helically developed along an axis extending through an afflicted body region to be treated, retaining means for retaining said turns in position external to the body, said coil comprising axially spaced helices of plural turns, the spacing between said helices being at least no greater than the effective diameter of said turns, and means for electrically exciting said coil with a succession of low-voltage unidirectional asymmetrical pulses.

8. The treatment device of claim 7, in which said spaced coil helices are electrically connected in series.

9. An electromagnetic body-treatment device for surgically non-invasive modification of the growth, repair and maintenance behavior of living tissues and cells by a specific and selective change in electrical environment, comprising coil means having plural turns generally helically developed along an axis extending through an afflicted body region to be treated, retaining means for retaining said turns in position external to the body, said coil means being electrically interrupted at its center to define two halves, said halves being electrically connected in parallel and in flux-aiding polarity, and means for electrically exciting said coil means with a succession of low-voltage unidirectional asymmetrical pulses.

10. Electromagnetic body-treatment coil means, comprising a longitudi-nally split tube of compliant non-magnetic material which is transiently deformable in the course of assembly to a body member to be treated and which when thus assembled is circumferentially continuous, and two like coil-winding subassemblies each of which is removably assembled to a respective end of said tube, the assembled axial spacing of said coil-winding subassemblies being less than their effective diameter, and flexible means for electrically connecting said coil-winding subassemblies for concurrent excitation in flux-aiding relation.

11. The body-treatment means of claim 10, in which each of said coil-winding subassemblies comprises a plurality of winding turns embedded in a cured annular body of non-magnetic hardenable material having a counter-bore at one end in telescoped assembly over an end of said tube, the inner end of the counterbore defining a flange to limit the telescope assembly upon abutment with the tube end.

12. An electromagnetic body-treatment device for surgically non-invasive modification of the growth, repair and maintenance behavior of living tissues and cells by a specific and selective charge in electrical environment, comprising coil means having plural turns generally helically developed along an axis extending through an afflicted body region to be treated, retaining means for retaining said turns in position external to the body, said coil means being electrically interrupted at its center to define two halves, said halves being electrically connected in series and in flux-aiding polarity, and means for electrically exciting said coil means with a succession of low-voltage unidirectional asymmetrical pulses.