CA1157527A - 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 main-tenance 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

BACKGROUND AND BRIEF DESCRlPl'lON OF THE INVENl'ION
This invention relates to the treatment of living tissues and/or cells by altering ~heir interaction with ~he charged species in their envi-ronment. In particular, the invention relates to a controlled modification of cellular and/or tissue growth, repair and maintenance behavior by the ap-plication of encoded electrical information. Still more particularly, this invention provides for the application by a surgically non-invasive .~

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1 1575~7 dire~t inductive couplin~, of one or more electrical voltage an~ concomitant current signals conforming to a highly specific' pattern .
Several attempts have been made in the past to elicit a 5 response of li~ing tissue to electrical signals.
Investigations ha~e been conducted involving the use of direct current, alternating current, and pulsed signals of single and double polarity. Invasive treatments in~olv.ing the '' use of imPlanted electrodes have been followed, as well as non-... . . . . ...... .
invasive techniques utilizing electrostatic and electroma~netic fields. Much'of the prior work.tha-t has been done is described in Volume 238 of thè Annals of The New York Academy o~-Sciences published 11 October 1974 and entitled "Electrically Mediated Growth ~Iech~nisms in ~i~ing Systems" (Editors A. R. Libo f'and ..
R. A. Rinaldi~.. See also '~Augmentation of Bone Repair by Induct~vely Coupled Electromagne~ic Fields" by C. Andrew L.
Bassett, Ro~ert 3; Pawluk and Arthur A. Pilla published in -Volu~e 184, pages 575-577 of'Sci'ence ~3 May 1974).
The invention herein is based upon basic cellular studies .' 2Q and ~nal~ses whlch'involve a detailed consideration of the 'intexactions of charged species, such as divalent cations and hormones at a cell's ~nterfaces and junctions..
Basically, it has been established that, by changiny the electrical and/or elèctrochemical environment of a living cell and/or'tissue, a modification, often a beneficial therapeutic effect, of the grow~h, repair and maintenance behavior OL said tissue and/or cells'can be achieved. ~his modification or effect is carried out by subjec-ting the desirea area-of tissues .and/or cells to a specifically encoded electrical vol~age and .
concomitant current, whereby the interactions of charged species l 157527 at the cellsl surfaces are modified. Such modifications en~ender a chanye in the s-tate or function of the cell or tissue ~/hich may result in a beneficial influence on the treated si-te. For e~ample, in -the specific case of bone gro~th and repair, it is possible ~?ith one electrical code, hexeinafter referred to as Mode l, to change -the interaction' of the ion such as Ca2'~ with a cell's membranes. ~7hereas, with anot~er eleetrieal code, hereinafter refexred to as .
Mode 2, a modlfication in -the same cell's pro~ein-s~nthesis ~ 10 eapabilities ean be affeeted.
For e~ample, -tissue-culture experi~ents involving the study of embryonie ehick~limb rudiments show that the use of a ~lode 1 code signal elicits enchanced Ca2~ release of up -to 50O from the competent osteogenie eell. This e~fect is highly specific to the parameters of the electrical code o~ Mode'l.
Thust this eode influences one major step of ossi~ieation, i.e ,' the mineralization of a bone-~rowth site. Sim}lar tissue-eulture studies using Mode 2 code siynals have demonstrated ' that this code is responsible *or enhaneed protein produetion from similar eompetent osteogenic eells. This lat~er effect is .
also hi~hly speeifie to the parameters oE the electrical eode of Mode 2~ In other words, this eode af~eets eertain metabolie processes for these t~pes of cells such as those involved in ealciu~ uptake or release from mitochrondria as well as the synthesis of collayen, a basic s-tructural protein of bone.
These studies show that -the electrical codes of Mode 1 and Mode 2'elicit individual tissue and eellular responses, indicatiny that each code contains a highly specific informa-tional content therein. Based upon these and other studies, 3~ i-t has been possible to utilize Mode 1 or Mode 2 siynals or a -!

particular co~ina-tion oE ~lode 1 and ~lode 2 signals to achiev2 a specific response requixed to enable the functional healiny of a bone disorder. These electrical modes have been applied successfully to human and animal patients for non-healing fractures such as congeni-tal pseudar~rosis and non-unions as well as fresh -Eractures.
Successes achieved in -the congenital pseudarthrosis cases are particularly note~orthy, since normally 80~ of children thus afflicted require amputa-tion, since conventional treat-ments such as bone yrafting and internal fixation areunsuccess~ul.
While there have been many investigations in the past of the response of living tissues and/or cells to electrical signals, clinical results to date using prior techni~ues have not been uniformly success~ul or generally accepked within the appropriate professional community, Several xeasons contribute to this state. First, it has not been realized heretofore that electrical signals of ~ery specific informational content are required to achieve a specifically desired beneficial clinical effect on tissue and/or cells. Second, most of the prior techniques utilize implanted electrodes, which by vir-tue o~ -unavoidable faradaic ~e:Lectrolysis) effects are often more toxic than beneficial in the treated site. Furthermore, ~he cells - and/or tissues are subjected to a highly uncontrolled current and/or voltage dis~ribution, thereby co~promising the ability of the cells to respond, should they do so, to the applied si~nal. This highly uncontrolled curren~ and/or voltage distribution also applies in the case of capacita~ively coupled 29 si~nals.

, In contrast, th2 sur~icall~ non-invasive direct inductive coupling o~ electrical informational con~ent of specific electrical codes as involved in the present invention produces within living tissue and/or cells a con~rolled response.' In ~rie~, the present invention involves the recognition that the gro~th, repair and maintenance behavior or living tissues and/or c211s can be modi~ied beneicially by the application thbreto of a specific electrical informa tion, This is achi'eved by applying pulse waveforms of volta'ge and concomitant current of specîfic time-frequency-ampli-tude relations to tissue'and~or cells by a surgically non-invasive means through use of a ~arying electromagnetic field which is inductively coupled through direct induction'into or upon the tissue and/or cells under treatment. -The informa-tion furnished to the cells and/or tissues by these signals is designed to ' ., . . : . .
influence the behavior of non-excitable cells such as those in~olYed in tissue'growth,' repair, and maintenance. These growth, repair and maintenance phenomena are substantially different from those`involved in excitable cellular aeti~ity (e.g., nerves,'muscles, etc.), particularly with respect to ' the type of perturbation required. Thus, the ~-oltages and concomitant curren~s impressed on the cells and/or tissues are at least three orders of magnitude lower than those required 2S to effect cellular activities such as cardiac -pacing, bladder control, etc.
The invention will be more completely understood by reerence to the following detailed descrip~ion, in conjunction 29 ~Yith the accompanyiny drawinys, in which : . . . ~. .

1 15 7~27 Fiy. 1 is a simpli.fied vie~ sho-~ing the treatment of a bone in accordance with the invention;
Fi~. 2 is a perspective vi~w oE the treatment unik shown in Flg. l;
Fig. 3 is a vie-~ ~xom the rear) of the unit shown in Fig. 2, showing the ~ositioning of a coil therein used for treatment purposes;
Fig. 4 is a block diagram of an electrical system for energiæing the coil sho~rn in Fig~ 3 for ~ode l treatment~ ..
Fig. 5 is a block diagram of an electrical syste~ for energizing the coii shown in Fig. 3 for ~ode 2 trea-tment, Figs. Sa and 5b are pulse waveform diagrams for Mvde l and Mode 2 treatments, respec~ively, showing presently pre-fexred pulses as induced in living tissues and cells;
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lS Fig. 6 shows alternative forms of negative pulse portions ~or Mode 2 treatment;
Fig. 7 i.s a fron~ ~ie~ of a body-treatment device, being an embodimen-t in substitution for that of Fig~ l, and shown un~olded, in readiness for wrapped application LO an afflic~ed boay xegion; .
Fig~ 7A is a sectional vie~, taken at 7A-7A of Fig. 7;
Fig. ~ is a perspec~ive view of a locating element for use with t:he device oE Fig. 7;
- Fig. 9 is a simplified schema-tic illustration of à method o~ use of the device and element OL FigsO 7 and 8;
~ ig. lO is a simplified right-sectional view through a bod~-limb cast to wQich the device and element of Figs. 7 and 8 have been appliedi . Figs. ll and 12 are sLmpli~ied views in perspective showin~
30 further body-treatment devices, for particular purposes;

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1 ~5~527 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 b respec-tively schematically representing ~ront 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 Pigure 11 are views similar to Figures 11 and 12 to show coil arrangements for further body treatment devices.
D~TAILED 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 repr0sentative of the application o the invention to the stimulation of bone growth for healing purposes.
A treatment head 14 is positioned outside the skin of the person, and is held in place by use of a strap 16 ~secured to head 14 by fasteners 16a) which may include \fielcro material 18 thereon so that the strap may be wrap-ped 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 that the treatment head 14 is generally curved on 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. ~s shown in Figure 3 the coil 22 is generally rectangular 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 ~ r,y.~ q,~

~ -7-1 1575~7 en-r~i~ing circui~, as ~ill be explained below in more de-tail. ~ diode 27 may be included wikhin the cable 26 for connection across -the coil 22 ~s ~7ill also be explained belo~.
The treatment heaa la is positioned on the patient so that the "~indow" formed by the coil 22 is adjacent the bre2k 12, i e., adjacent the tissue under treatment. The coil 22 is energized, as will be e~plained in more detail belot~, and induces an electrical potential within the tissue 10 under trea~ment. It has been found that a paxticular type of signal should be induced wi~hin the tissue and this is achieved by energizing the coil 22 by a circuit, such as shown in Fig. 4 or Fig. 5, to produce the pulse signal shown in Fig. 5a or Fig. 5~. -Refexring to Fig. 4, a variable dc supply 3~ is coupled through a gate 32 to the trea-tment coil 22 (or coils, as the case may be, and as will be explained in more détail below~.
The gate 32 is under the control of contro]. un ts 34 and 36 which cause a pulse signal consisting of repetitive pulses of electrical potential to be applied to the trea-tment coil - 22. Each pulse, as shown in Fig. 5a, is composed o~ a "positive" pulse portion Pl followed by "negative" pulse - portion P2 because o~ the stored electrical energy wi~hin the treatment coil. In the circuit of Fig. 4, a diode clamp-ing unit 38 may be employed to limit the pe~k potential of that negative pulse portion. The diode clamping unit 3~ may be one or more diodes connected across the coil 22, and may be advantageously located wi-thin the cable 26. The diode 27 29 sho~ln in Flg. 1 constitutes such a clamping unit 38.

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~ In Fi~J. 5a, the signals at the trea-bment coil 22 and hence the induced signal ~ithin the ti5sue to be treated are shown. ~t time tl, i-t is ass~lmed th~t yate 32 is ~ated on by an appropriate signal from control unit 36 (d~signated a pulse ~idth 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 Fis. 5a. T~e signal across the trea-tment coil decays in a second pulse segment along th~ portion of th~e curve designated 40 in Fi~. 5a. The slope oE that curve is determined ~y the L/~ time constant of the circuit of Fig. 4, i.e., the inductane of the treatment coil and the e~fective resistance of the circuit, including distributed factors of capacitance, inductance and resistance. For treatm~nt of many tissues ana cells r it is believed desirable to adjust the circuit parameters so that the portion 40 of the curve is as fla~ as possible, renaering the signal applied to the treatment coil 22 as rectangular in shape as possible.
At the time t2, the gate 32 is gated o~r by ~e control unit 36.`
Just prior to bein~ gated off, the signal across -~he trea~ment coil is at the potential v~ shown in Fig. 5a. The poten~ial across the treatment coil drops from the level v2 in a third pulse segment 41 to a potential o~ opposite polarity designated v3 in Fig. 5a. The magnitude o~ the opposite polari-ty 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, ~inally effectively - 30 reaching that level a~ time t3. A pre_etermined period passes -_9_ beEore t~e pulse-repetition ra-t~ control unit 34 generates . an appropriate timing SicJnal to trigger the control unit 36 to generate a signal to turn gate 32 on ~gain to 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 varia~le to control pulse duration and repeti~ion rate within desired limits. Furthex, the use of a variable dc supply 30 permits vaxiation of the am~litude of the pulse signal as desired. - .
Nhen pulse-train operation (Mode 2) is employed,.
additional t~lin-~ circui~ry similar to units 34 and 36 in Fig. 4 is emplo~ed to provide the burst-segment width and '.
the burst~segment repetition ra-te. Referring to Fig. S, contxol units 35 and 37 control ga-te 33 -to produce a signal applied to coilLs) 22 of the wa~eform type as shown in ~ig.
5b. The circuit is otherwise -the same as in Fig. 4, except that'the diode-'clamping unit 38 is omitted to permit the large negative-pulse portions as shown in Fig. 5b. The 20' con~xol units 3~ and 37 aetermine ~he number of pulses in a '.burst and the time between succes'sive bursts.
It has been found that the signal across the treatment coil 22~ and hence the induced signal within the tissue under treatment, should satisfy cer~ain criteria. These criteria ' will be specifi'èd with respect to the signal as induced in the tissue and/or cells under treatment. Such induced signal ma~
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be monitoxed, if desired, by use of an auxiliary monitoring pickup coil (not shown~ ~hich is positioned at a distance from the treatment coil 22 corresponding to the distance of the 30 tissue under treatment from that coil, as ~lill be explained..

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in more det~il belo~ n any even-t, it has been ound that the follo~iing criteria should be satisfied for eefective treatment of livincJ tissues and cells, in particular, hard tissue such as bone.
In the following presentation, the signals sho~7n in Figs. 5a and 5b constitu-te the pulses OL electrical potential and concomitant current gener ted by the coil and impressed upon the tissues and~or cells. These pulses have one polarity upon l'energization" of the coil (~ermed herein the "po~itive" pul5e portion and shown as the positive-going portion of the waveform on Figs. 5a and 5b).
These pulses have an opposite pola itv,upon "de-energization"
o the coil Ctermed herei'n the "negative" pulse portion and shown as ~he neyative-going por-tion of the waveforms o~ Figs.' 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 pbrtions of opposite polarity'r with respect to a reference potential level, are involved.
It has heen determined tha~ the "positlve" pulse portions should bear a predetermined relationship to the "negative'l ' - pulse portions'in order to modi~y beneficially and with uniform results kile behavior of living tissues and cells. This pre-dete~lined realtionship has been achieved by the utilization of -two di:Eferent signal modesr as well as combinations thereof.
In Mode 1 (see Fig. 5a~, the asy~metrical waveform induced in tissue or cells by the alternate energization and de-enersiza-tion of an'electromagnetic coil is repeated-at a rrequency such that the overall duty cycle is no less than about 2%. This fre~uencyr in Mode 1, has typically been about 10-100 Hz with du~y cycles of 20-30~, The basic relationship for ~,od~ 1 of 1 ~ 575~7 the respective frequ2ncy ~mplitucle content of the '!positive"
and "ne~ative" pulse por-tlons is as follows: pulse sig~al should be of a particular shape, namely, each "positive"
pulse portion should be composed o~ at least three segments, 5 e.g., the segments 39, 40 and 41 in Fig. Sa. As noted above, it has been ~ound that a substantially rectangular shaped "positive" pulse signal portion is particularly use~ul in the treatr~ent o~ tissuè and cells. However, it is possible that other puls~ con:Eigurations tother than a simple two-sesment spi~e) may be use~ul. The peak amplitude of the final.seyment o each `'positive" pulse portiont e.g., the potential v2 in Fig. 5a should be no less than about 25% of the peak amplitude of the first se~men-t 39 of the 'Iposltive" pulse portion, eOg., the potential vl in Fig. 5a The peak "ne~ative" portion amplitude is deno-ted by V3 in Fig. 5a. This peak amplitude should be no more ~han about 1/3 the peak amplitude oE the "positive" pulse por-tion. .The time duration of each "positive" pulse portion ~the period that elapses between times tl and t2 in Fig. Sa) should be no longer than about ~/9 the time du~ation of the followlng "negative"
pulse portion tthe time elapsing between times t2.and t3 in - Fig. 5a~. Because the treatmen-t system uti.lizes an electro-magnetic coil, the energy of each "positive" pulse por-~ion is equal to the energy oE each "negative" pulse portion, i.e., the area in Fig. 5a er~raced by -the "positive" pulse portions is equal to the area embraced by the "negative" pulse portions.
By satisfying the criteria just mentioned, the energy of each "negative" pulse por~ion is dissipated over a rëlatively lon~
period of tirne, and the average amplitude of that negative pulse portion is limiled. It has been found ~at such average . -12- .

negative amplitude snould be no greater than ahou-t 1/6 the average ampli~ude of -the l'positive" pulae portion These relationshlps also ensure that the l'positive"
and "negative" pulse portions have the proper frequency-amplitude characteristics within themselves and to eachother such that a beneficial modification of the behavio.r of tissues and cells is accomplished.
Besides the relationships just mentioned, it has been found t~at the average magnitude o~ the "positive" pulse portioIl peak potential should be within ~he range of about 0.0001 to 0.01 volt per centimeter of tissue or cells, corresponding to be~een about 0.1 ana 10 microam~re per square centimeter of treated tissue and/or cells (based upon typical cell and -tissue reslstivities) It has been found that hi~her or lo~er pulse potentials will not result in a .. beneficial effect, It has al.so been found that the duration of each "posi-tive" pulse portion.(the tLme.elapsed be~ween .
times tl and t2 in ~ig. 5a~ should be at least about 200 micro-seconds. If the time duration of each "positive" pulse portion 20 is less than about 200 microseconds, the tissues and cells ~re.
not stimulated sufficien~ly to modify the repair or other processes~ From a practical standpoin~, the "positive" pulse portion duratlon should not be greater than about 1 millisecond.
. It has also been found that the repetition rate of the pulses shoul~ be within the range of about 65 -to 75 Hz for bone and other hard tissues. Pulse treatments wi-thin this range have been found to be particularly efEective with re~roducible results for tissues and cells of this -type. In general, ho~ever, pulse repetition rate should be be~een about lQ and 100 Hz for ~ood results in tissues and cells.

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1 ~57527 For the treatm2nt of bone disorders, and particularly for the treatment oE pseudarthrosis, it has been found that for ~lod~ 1 an optimum induced "positive" pulse si~nal portion having a peak amplitude of between about'l and 3 millivolts per centimeter o treated tissue (1 to 3 microam2eres per s~uare centimeter of treated tissue and/or cells) with the dura-tion of each ~Ipositive~ pulse portion being about 300 .
microseconds and the duration of eac~ o the "negative" pulse portions about 3300 microseconds, and a pulse repetition rate.
10 .o~ about 7Z ~Iz, rep.resents a presently pre~erred and optimum induced pulse treatment as long as the pulse-shape requirements ~ . .
noted above are me-t. Total treatment times may vary. It is presently ~elieved that pulse-signal treatments.for periods ' e~ch lasting for at least about 15 minutes, with one or more periods of trea-~nent during a prescribed number of days, may .
be eflective-in.stimulating tissue and cell behà~iort A pre-. ferred treatment regime using,Mode 1 has been found to b.e a - . minimum o~ 8 hrs/day for,a period of four months in di~ficul~
cases, and two weeks in less difficul-t cases.
. In Mode 2 treatment ~Fig. 5b)-, the asymmetrical waveform induced in tissue or cells by the alterna~e.energization and de-ener~ization of an electromagnetic coil is .applied in a .
pulse-train modality, which contains bursts tpulse groups) of as~mmetrical waveforms. Each burst of asymmetrical pulses has a duration such that the duty cycle of the buxst portion is no less than about'1%. The burst ~requency has typically been-about from 5-50 ~Iz.
The basic relationships for Mode 2 of the respective requency-amplitude con-tent of the "positive" and "negative"

pulses within the burst section o~ the pulse train are as .,, -l~t~

1 ~57527 follo~ls: ~ach "positive" pulse portion should be co~posed o~ at least three segmen-ts, e.y , the segments 39', 40' and ~1' in ~'iCJ . 5b. For -this mode, it has also been ~ound t~at a substantially rect~Ilgular shaped "positive" pulse-signal portion is particularly useful in the treatment oftissues and cells. However, it is possible that pulse con-figurations other than a simple two segment spike may be useful. The peak amplitude of the final se~men-t of each "positive" pulse portion, e.g., the potential v2 in Fig. 5b, should be no less than about 25% o:E khe peak amplitude o~
the first segm~llt 3~'of -the "positive" pulse portion, e.g., the potential vl :in Fi~. 5b.
The peak "nec~ative" amplitude ls denoted by V3 in Fig.
5b. This `'negative" pea~ amplitude should be no more than about ~0 times the "positive" pea~ amplitude ~in -this case vl~.
This re~uirement may ~e met by utilizing l'negative" pulse portions having several different waveshape forms, e.g./
substantially rectangular, ~rapezoidal with exponential decay, bell-shaped, or single-spike with exponential decay, as in xepresentative waveforms a, b, c an~ d in Fig~ 6~
The duration of ~ach "positive" pulse portion (-the time that elapses between times tl and t2 in Fig. 5b) should be at least about 4 times the duration of the followin~ "negativel' pulse portion ~the time tha-t elapses be-t~een times t2 and t3 in Fig~ 5b)~ As noted above, since the treatment system utilizes an electromagnetic coil, the energy of each "pos-itive"
pulse portion is equal to the energy of each "ne~ative" pulse portlon, i.e., the area in Fig. 5b embraced by -the "posl~ive"
pulse portions is equal to the area embraced by the "negative"
pulse portions.

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-15- , 1~57~27 The pulse-repetition rate o~ the pulses within the burst se~.ent of the ~lude ~ pulse train (the time elapsing between times tl and t~) can be bett~een abou-t 2000 Hz and 10, ooo }~z, The width of the burst segment of the pulse train (the time elapsed between tl and t5) should be at least abou-t 1 of the time elapsed between tl and t6.
By satisfying the criteria just mentioned, -these relationships also ensure tha-t the "positive" and "nega-tive"`
pulse portions have thè proper frequency-amplitude character-istics within the~lselves and to each other such that a beneficial mocliE.ication o the behavior of tissues and cells is accomplished.
Beside~ the re~.ationships just mentioned, it has also been found that -the average magnitude of the "positive" peak potential should be within the xange of about O.OOOOl to 0.01 ~olts per centimeter of tissues and/or cells (bet~een about 0.01 and 10 microampere per square centimeter of treated tissue and/or cellsl~
It has been found that hi~her or lower pulse potentials .
will not result in a beneficial effect on tissues andJor cells.
It has also been found that the duration o each "positive!' pulse portion in the burst seyment of the pulse train (i,e , the time elapsed between tl and t2 in Fi~. 5b~ should be at least about 1000 microseconds. It has also been found that the repetition rate of the burst segment should be within the ranye Gf about 5-15 Hz for bone and o-ther hard -tissues Each negative-pulse portion within the burst segment of the pulse txaill should be of a duration no greater than about 50 microseconds and of an averaye amplitude no greater than '~`

1 157~27 about 50 l~v/cm of tr~ated tissu~ and/or c~lls (about 50 ~icroa~?eres per squ~r~ centimeter of treat~d tissue and/or cells).
For the trea-bment of bone disorders, and particularly for the trea~ne~t of pseudarthroses and non-unions, i-t has been lound that an optimum induced "positive" pulse signal portion naving a peak am~litude of between about 1 and 3 millivol~s/centime-ter of treated tissue ~i.e., 1 to 3 micro-amperes per square centimeter of treated tissue and/or cells), wi,h the duration of each "positive" pulse portion being about 2Q0 mic~oseconds, and the duration of each of the "negative"
pulse oortions being about 30 microseconds, and a time elapsed bet~een times t3 and t4 oE Fig 5b o 10 microseconds, and a pulse repe~ition rate of abou~ 4000 ~z, and a burst segment width of a~out S milliseconds, and a burst repetition rate o about lQ Hz, represen-ts a presently preferred and op-timum induced pulse treatment in bone -for Moae 2, as long as the pulse re~uirements noted above are met.
It is also believed that a single asymme~rical pulse as described in the burst segment of Mode 2 can be employed at a repe~ition rate similar to that used in Mode 1 ~or beneficial modification of tissue gro~th and repair.
Trea~ment of livin~ -tissues and cells by -~he above me~ods herein, in particular for hard tissue such as bone, has demon-~5 st~ated an increased repair response and generally uniformresults have been at-tained throughout all patient and animal trea~ments. Particularly beneficial results have been obtained in the cases oE treatment of pseudarthrosis in whlch a bone union has been achieved followin~ previous unsuccessful a-t~empts by o~her treatment me-thods and in which amputatiOn has been discussed as a possible alterna~ive to regain function , _7 7_ I 1 57~27 In pr~ctlce, it is beli~ved desirable to utilize as large a coil "windo~" as possi~le and to posi tion th~
coil such that an adequate flux density is impressed upon the tissu2 and/or ceIls bein~ trea-ted. As is known, a time-varving magnetic field induces a time~vary~ng voltage field orthogonal to it. That is, the ~eometry of the magnetic-field lines determines the geometry of the induced-voltage field. Because a relatively uni~orm induced-voltage field i5 dèsired, ~he geometry of the magnetic-field lines should be as uniform as possible, which may be achieved by rendering the size o-f the coil relatively large with respect to th~e area ~Inder -treatment. At this particular time, it is not believed that thère need be a particular orientation between the magnetic-field lines and the -tissue and/or cells being treated.
It is believed that the uniformi~ of the induced-vol~age field possi~le through electromagnetic trea-tment is responsible in many rèspects for the good treatment results which have been cbtained, in distinction to ~e non-uniform ~ields which may and probably do resul-t uith other types o~ trea-tments, 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 medi~ or an insulator~ Tne field characteristics will in general be -the same ~within one percent~ in these three cases, except in the case for which an induced curren-t flow i5 suf~ficien-tly great to create a back electromotlve force to distort the magnetic field lines. This condition occuxs when the conduc-ting medium has a high conductivity, eOg., a metal, ~,3 _ ~ :a57s~7 and is lars~ enough to .intercept a substantial number of ma~netic-field l.ines~ I,iviny systems, i.e., tissue and/or cells, are much le5s of a con-luctor ~han a t~pical metal (generally by ~t least 105, i.e. five orders of maqnitude). Because o 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 gro~th process continues. .
Thus, with non-invasive electromagnetic treatment, it is believed that the potential gradient that is produced ~Ji-thin the tissue and~or cells is constant re~ardless of the stage or condition o~ the treatment.
Such uni~o~ity oE induced potential is virtually impossible to be achieved through the use of implanted electrodes or b~ eIectrostatic coupling or b~ a transformer coupled to electrocles, or by implanted coils coupled to ' electrodes. Since't~ese'latter types of treatments are.
dependent upon conducti~ity, which wiil vary within tissue and/or cells, the'induced potential gradient will not be constant as the conditiQn oE the tissue and/or cells Ghanges.
Additionally, at any particular time within tissue and/or '.
.cells, individual localities of the material being ~reated will have different conductivity characteristics r which will result in differing;potential gradients throughout the material treated.
~5 For these reasons, it is believed that a surgically non-inYasiYe electromagnetic treatment oE tissue and/or cells i5 greatly preferable to electrical trea-tment by o~her means.
Regarding ty~ical coil parameters, it is believed that for -typical bone breaks, coil ~Jindows oE about 2.0`' ~ 2.75"
(for an adult) and 2" x 1.5" Ofor a child) are suitab~e.

~l9-The wirc em~loyed in the coils may be B&S c~au~e 12 copper wire tha~ 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 believecl that the inductance of the treatment coil should be between about 1-5000 microhenries, and pre-ferably between about lO00 and 3000 microhenries, with suf~ieiently low resistance (e.g., 10 2 to 1 ohm) 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 lessier the inductance of the treatment coil, the steeper the slope of the eurves 40 and 40' as shown in Figs. 5a and 5h; the greater the inductance, the flatter or more reetangular is the "positive" pulse that is produeed.
The monitoring o the induced potential may be by actual electrodes making eontact with the tissue and/or cells being treated or by use of a pi.ckup coil positioned ac1jacent to the treatment coil 22 at a distance corresponding to the distanee of the material under treatment from the coil. A typical pick-up eoil tnat has been employed is circular, about one-half eentimeter 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 centimete.rs) to provide.an induce.d voltage per centi-mete.r number that is elosely related to the volts per centimeter induced in the tissue and/or cells under trea-tment.
A typical treatment utilizing a coil having a "window"

2" x 2.75" and 60 turns of number 17 gauge wire, includi.ng a diode at the coil such as the diode 27 in Fig. l, produced the following induced voltages in a pickup coil* for the pulse times *These voltage values may bë translated into millivolts per centi-meter of ~issue, by dividing by a factor of substant.ially ten.

. -20-1 1S7~27 (in microseconds) as follows (vol-tages ~nd times axe with reEerenc~ to the waveorm o~ Fi~. 5~:
Induced Vo:Lta~e vl ~2 v3 tl-t2 t2-t3 S ~la~imum (at face of treatmQnt eoLl) 22 17 3.7 300 4200 5/~" fro~ face of treatment coil 15 11.5 2.5 300 4200 1 1/2" from ace of treatment coil 6.0 4.2 1.0 300 4200 The use of pulsing electromagnetic fields to control bone fo~mation in a variety of conditions, no~, is on a sound e~perimerltal and clinical basis. Thus far, the develop~ents have had application in treating sueeessfully congenital and acquired pseuaarthrosis and ~resh fractures in humans~ increasing the rate of fracture and reactive periostitis repair in animals, and reducing bone loss in dis~
use QS teoporosis of long bones. Success with the method hinges on the discovery of pulse patterns with specifie time-frequency-amplitude relationships as outlined above - ~X~PLES
In order to demonstrate efficacy,the utilization of direet inductive coupling of eleetromagne-tically induced pulsing voltages-and concomitant-current via Modes 1 and 2 and combinations thereof for hard tissue growt~ and repair t~as initially applied in cases of congenital and acquired pseudarthrosis. In a group of pa-tients,only individuals who had been -treated previously by one or more unsuccessful surgical attempts (grafting, internal fixa-tion) were accepted.

For most of these patients, amputation had been reco~mended by at least one qualified orthopedis~. Throughout this study, the necessity for pulse specificity was illustrated again and 33 again. For e~amole, when lac~ of ossification was the primary ~ 157527 problc~ (usua]ly the case for congenita~ pseudarthroses), ~1ode 1 tr~a~ment~s u-tilized ~ith final functional bony union occurring on~y when the parame-ters of the pulse corresponded to those given above. On the o-ther hand, wh~n lack of bony matr:ix was the primaxy problem, Mode 2 treatment was employed in order to achieve the production of collagen which is the primary supporting protein in bone structure. Since protein procluction and ossification are two completely different steps in bone formation, the highly selective na-ture oE each of the sig}lals utilized in Modes 1 and 2 could be synergistically combined when neither matrix production nor os-;ification were present in a given patient's treatment history~ Thus, a combination of Modes 1 and 2 was utilized ~ith benefit in this type of si-tuation.
In the caCe of congenital pseudarthroses, the typical patien~ is ~e~ween 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 un-success~ul surgical procedures and had the condltion ~or an ~verage o~ 5 years,and all were candidates for amputation.
The treatment;o~ such a patient was noxmally carried out using Mode 1 treatment regime since the primaxy pxoblem 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 txeaument on an out-patient basis. Treatment time is typically lZ 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.

.

l 1S752~

~ or acquired pseudarthrosls, either traumatic or operat:ive, pa-tients are mostly adults and had an average number o~ three failed operations and an averaye of 2.5 years from on~et oE non-union~ ~mputation had been discussed for s-even-ty percent o~ these individuals. Since - in so~e cases the primary problem was lack of bony matrix, typically visible radiographically as gaps in the bone of more than 2 mm in the frac-ture site, such a pztient was treated com~encing with Mode 2 modality. When it was thought that sufficient non-ossified bony matrix was presen-t, Mode 1 modality was employed to ~ain rapid immobilization of the fracture si-te.
~ ecause o~ the particular pathology of several patients in this group, a combination of Modes 1 and 2 was employed with this ttreatment being specifically Mode 2 follo~ed by Mode 1~ ~s in the case of congeni~al pseudar-throsis, the proper e~uipmçnt was prescribed by the attending orthopedic surgeon and treat~ent was performed on an out-patient hasis.
Trea~ment time is typically 10-14 hours/day for periods ranging from 3 to 9 months.
~ ome 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 demons~rate that once the particular pathology of a bone disorder is dia~nosed it can be select:ively ~eneficially treated by the application of properly encoded changes in electrical environment.
Similar findin~s have been obtainea from a study of bilateral fermoral and radial osteotomies in 160 rats. These animals were divided into two ma~or groups; field exposed and -.

1 15752~

con~rol for an interval of :L4 days aEter opera~ion.~ollo~in~ sacrifice, the e~tent oE fracture repair was judged on the basis oE X-ray and histolo~ic evaluation, cou~led ~tith non-destructive mechanical testing. These animal mo-lel~ ~rere employed to evalua-te the effectiveness of treatrent modalities of ~odes 1 and 2 and combinations thereof~ Generally, when the osteoiomy gap was less than 1 . n mm, a Mode 1 signal was ef~ective since very little bony m~tri~ was r~tired for solidification. On the other hand, for wider 05 teotomies, substantially increased matrix production ~qas ob.served over control animals when Mode 2 was employ2d. ~ co~bination o Modes 1 and 2 was employed in the lat-ter case to obtain a stiffer repalr site for an equivalent treatment time.
Th~s ~as fur-ther evaluated by -the response o~ these bones to mechanical testing. This was performed b~ subjecting ~he bone of t~e rats following sacrifice to cantilever loading at ~arious de~o~mations .~n accoxdance with,the tes-ting proced-ures described in "AcceIeration of Fr,acture Repair by-Electro-magnetic Fields. ~ Surgically Non-invasive Method" by C. A. L.
Bassett, R. ~, Pa~lùk and A. ~. Pilla, published on pp~ 242-262 o~ the Annals of_The New York Academ,y of Sciences referenced abo~e, The specimens were deformed in the antero-posterior, lateral-medial, pos-tero-an-terior, medlal-lateral and again ~he antero-posterior positions.
The avera~e response o~ a femur to this test at a delormation of 0.05 inch is shown in Table I as follows:

, 'Ta~le I

ech~nic~l Lo~d Values In Electrical Stimulation of Arti~icial Osteotomies __ In Adul~ Female Rat Femur ' Load at 0.05 in.
Stimulation ~ De'formation .. . . . _ .
Control ~untrea-ted) 4~ gms~ ~ 5.2 gms.
~ode 1 Signal ~Figure 5a~ 580 gms _ 65 gms.
In addition to radiographic and mechanical evidence of the e fectiveness o~ the signa~ em~loyed, histologic evidence furtner attests to this effectiveness.
~ emoto~ylin and eosin stained longitudinal specimens sho-.~ a much higher degree o~ maturation for the Mode 1 signal than in t~le control case.
For wider osteotomy gaps, treatmen-t times of fourteen days shoT~ed th~lt the active animals had a significantly larger callus than controls. Histologic evidence shows that the increase is at least 15~% over controls.
Limited tooth'extraction studies have been performed and sho~ th~t pulses of the'Mode 1 ~ype may have a highly beneficial effect on the rate of healing and on bone loss ln the oral cavity. The latter'effec~ 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 electro-magnetic ~ields with highly specific pulse charac~eristics can be non-invasively inductively coupled -to biological systems to control cell behavior. In the initial application o~ 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., malignancyr - . .

' ' -25-1~S7~2~7 neuro-rc~air, inflal~natory processes and immune response, among others.
In summary, it i5 believed that a unique elec-tromagne-tic and sur~ically non-invasive treatmen-t techni~ue has been discovered. Induced pulse characteristics appear to be highly si~nificant, especially those relating to the time-frequency-amplitude relationships of tne entire pulse or pulse se~uence.
It is believed -tha-t selection of particular time-frequency-amplitude relat:ionships may be the key to successful treatments of varying cellular behaviox in a variety of tissues.
Througho~lt the specification for Mode 1, a preferred pulse repetition rate of bet~een àbout 65 and 75 Hertz had been specified :Eor 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 var~ dependin~ on the tissue and cell type. Positive results have been o~tained, for example, in soft-tissue treat-ment at 20 Hertz.
~t ~ill be appreciated that the methods and apparatus described above are susceptible of modification. For example, ~hile Figs. 1 and 2 illustrate a treatment uni~ which may be strapped to the leg, treatment units lncorpora-ted in casts, e.g., may be employe~. Further, treatment may be carried out by use o one or more coils of var~ing shapes positloned adjacent to tissue and/or cells to be treated. In fact, some trea-tments o~ humans have involved coils positioned upon opposite sides of a bone break. Coils ~Jith metal cores may also be used. In the case of trea~men~ within -the oral cavi~y, it is believed that double coils are advantageous, positioned, for example, on opposite sides o~ a tooth soc~et -to stimulate rep`air of that socket. Some specificall~ beneficial trealment units and procedures ~ill be described in connection with Figs.
7 ~o 16.

Fiys. 7 and 7A illustrate a body-treat~ent or ap?licator device which is most heneficially applied to tlle treatment of bone br~ks or non-unions in arm or leg members, i.e., wherein the bone recJion to be trea~ed is relati~ely elongate. The device comprises two coil-mounting u~its 50-51 each of which contains an electrical coil OL
the character already described, and they are ~lexibly interconnected to p~rmit ready adaptability to oppos~te sides o~ the region to be treated. Each of the UllitS 50-51 ma~ be OL like constr~lction, essentially involving a rigid .
pottins ol its coil turns in a consolida-ting mass of cured elasto~eric or p:lastic material, however, in the pre~erxed form, each unit, such as un~t 50, comprises a casing consisting of flanged concave-front and convex-back panels 5~-53, with the peri~heral flange 54 of fron-t panel 52 in continuous`
telescopin~ overlap to the similar flange 55 of back panel 53 Registering and abutting inwardl~ projecting boss~or foot form~tions in panels 52~53, as at 56, enable the t~Jo panels to be bolted together in the precisely spaced relation shown in Fig. 7A. The respective inner and outer panels of unit S1 are precisely the same as for unit 50s except that as a further feature of the invention a rectangular recess 57 is inwardly for~ed in panel 52, or a locating or key purpose to be later explained. The secured boss or foot formations at 56 are preferably of-Eset inwardly from the flan~ed 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, com-pressed as the bolted connections are established at 56.

5 ~ ~

The fle~ible interconnection o~ units 50-Sl is shown to include an electrical cable 59 ~or establishing the el~ctrically parallel interconnection oE like coils 58 in the respective units 50-51, the polarity o~ such inter-connection being such that magnetic-~lu~ lines within the t~Jo coils 58 and in khe space therebet~1een are flux-aiding when the ~ront ~concave~ panels of units 50-51 are in face-to-f2ce relation. Removable connection of ~e coils 58 to the energizin~ circuitry of Figs. 4 ox S is shown by way of the single plu~ an-l socket means 24-26, via uni-t 51. Typically, each of the two coils 58 has an .inductance in the order o~
5000 microhenries, so that in their preferred parallel relation the inductance p.resented to ~he outpu~ of the applicable one of the circuits o.E I?i~s. 4 and 5 is 2500 microhenries.
The flexible intexconnection of units S0-51 also includes .
articulating strap means, as of ~elcro material, to enable , s~mple adapt~tion to t~e dimensional requirements of each patient's particular.circumstances. Thus, unit 50 is shown with a ~irst such strap element 60 secured to its back panei .
20 53 and having a ~ree end e~tending a distance Ll to one laterai side of unit 50; similarly, unit-51 is shown with ano~her strap element fixed.to.its.back panel and having a first free end 61 of leng~h Ll extending laterally for adjustable overlapping connection to t~e free end of strap 60. The opposite end 62 of the strap carried by uni-t 51 is also free but of substantiall~
greater length L2, -to permit.full circumerential completion of the strap connection as the means of removably applying both units 50~51 to the body-member treatment region; preferably, the length L2 is sufEicient to enable the ~elcro-material region 63 at the inner or front face of the free end 62 to .

-2~~ . .

1 ~ ~)75~7 circumferent:ially envelop the body member and to enable Tegion 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 uni~ 51.
The coils 58 are shown to be of generally elliptical configuration. These coils should be of sufficiently large in-ternal dimensions, in relation to their ultimately installed positioning for bone treatment, as to assure relatively uni-formly distributed concentrated flux within the treatment zone.
Elementary principles and preferred dimensional relationships for a two-coil flux-aiding circular configuration will be later discussed, with a view to minimiæing the establishment of stray-flux lines between the two coils. It suffices here to point out that by employing the cylindrically concave-convex configurations described for panels 52-53, the coils 58 are necessarily also conformed to a geometrical shape which is cylindrically arcuate~
the major-axis direction of the ellipse being parallel to the axis about which each coil 58 is cylindrically arcuate. Thus, when units 50-51 are positioned for body treatment, the concave sides of both coils 58 are in face-to-face relation, with the minor-axis spaced coil regions m-n of unit 50 in closer adja-cency to the corresponding minor-axis spaced coil regions m'-n' of unit 50 than is the case for coil-to-coil spacing of corre-sponding major-axis spaced coil regions ~-q and ~-q'; as a re-sult of this relation, any tendency to establish stray-flux lines between corresponding minor-axis coil regions m-n' and m'-n is minimized.
-S~ecific use of the body-treatment device of Figures 7 and 7A will be more clearly understood through additional reference :````~

l 157~7 to E~igs 9 and 10, utilizing a locating-block or keying device ~sho~m in Fi~. 8) which may be expendable and of suitable molded plastic such as polyprop~rlene. The locating device of Fi~. 8 comprises a rectangular-prismatic block 65 which is dimensioned ~or removablelocating reception in the rectangular recess formation 57 that is c~ntral to the concave panel 52 of unit 50.
Integrally formed ~Jith and extending in opposite longi-tudinal directions Erom the base o prism 65 are elongate mounting strips ~,fi which'are relativel~ sti~ly'compliant for slight bending adaptation to particular body or cast configurations. ~iso, the'thickness and material of strips 66 should be s-~ch as to permit sheared cut o~f to shorter length, as may be needed ~or s~me applications. A pressure-sensitiye tape 67 r which may incorporate metal foil, wire orother material opaque to radiological irradia-tion is shown to be ~emova~l~ adhered to the peripheral edge of block 65.
- In the initial stages of use of the device of Fis. 7, .
i.e., during the period in ~ich the separate halves o~ a bone breaX or non-union are to ~e'fixedly retained ~or electro- ' 'magnetically induced ~reatment of the invention~ the afflicted limb, for example, the leg''70 of-Fig. 9,' is irst placed in a ' c~st 71 ~hich overlaps the afflicted region. The leg is then placed on a tahle 72 so that t~e afflicted region can be viewed under radiological irradiation, schematically designated by an arrow, with the legend "~~Rays", instantaneous and current viewing being provided by suitable video-scannin~ and display means 73-7~. The device of FLg. 8 is then placed upon a local region of the cast 71 such that the opaque periphery of prism 65 is viewable at 7~ as a rectangular frame, surrounding the .

~30-l :157527 central 7,0ne of the bone-brea~ or non-union region to be treatecl.
~7nen the opaque fr~me is seen in the displ~ in proper surround-in~ registry with the aflicted bone region, i.e., after such positioning adjustments as may be needed to assure such registry, the strip ends 66 are fastened to the c~st 71, as by means of adhesive taoe su~gested at 68. The cast 71 may then be further develo~ed over the strip ends 66 to assure permanence of the locating prism as a fixed part of cast 71. When prism 65 is thus fixea to cas, 71, strip 67 may be removed and discarded, and the patie~t i5 ready for the device, of Fig. -7, which is assembled by first locatin~ ~i.e., keying~ unit'50 vla recess 57 to the prism 65, by then adjustiny t~e ~elcro overlap 60-61 to position uni-t 51 in diametrically opposite relation to unit 50 (on the other ' side of cast 711, and'~y then using the strap end 62 or comple-' tion and securincJ o-f the'circum-ferential overlap described for ' the inner-sux~ace region ~3. The electrical'connection is then comoleted at 24-26, and treabment may commence in the manner - already described. It should be noted that, if the surface of the conca~e panel of each unit 50-51 is not soft-textured, -there may ~ a tendency to generate chal~ dust upon local mechanical fretting of the cast 71, with repeated assembly and disassembly o units 50-51 thereto.' Such fretting can be minimized by adher-' ing a oam~d-plas-tic or the like yieldable liner'to -the concave' panel of one or both units 50-51) such a liner being shown at 75 in ~ig. 10. Still ~urther, the use of a foamed-plas-tic liner wil assure greater patient comfort while frictionally contributing to stable p'l~cement and retention of the trea~ment coils.
Fig. 11 depicts a body-treatment device which is a 7~ c ~
- particularly suited to the treatment of bone a~lic~sn in the regio~ o~ the heel. For simplicity in Fig. 11, the sho.~ing - is limited to relatively rigid structural comoonents~ and the ., . `

~ -31-~ 15~527 foamed-plastic lining carried by such st:ructure for patient comfort (i.e., to avoid chafin~ has been omitted. Basically, the rigid structure of Fig. 11 comprises a tubular shell 80, as o meth~lmethacr.ilate, being open at its longitudinal ends and locally open at 81, over an angular span (about ~he shell axis) and intermedia-te the longitudinal ends of shell 80. An "S"-shaped strap 82, which may be of -the same material as shell 80, has its upp._r end secured at 83 to the back end of shell B0, at oDening Bl, and i~s lower end 8~ ex~ends along the 10 diametrlcally opposite region of.the inner surface of shell 80, to define a plate for basic support oE the bottom of a foot 85, to be inserted vi~ the opening 81. The respective courses of two arcuately cuxved ellip~ical coils 86-86' are schematically indicated by heavy dashed lines. These coils will be understood lS to be ~onaed to shell 80 in vertically opposed relation, the upper coil 86 beinct bonded to the inner surface of shell 80, just inslde -~he edge of opening 81, and the.lower coil 86' being similarly bondea 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 t , . .
once the latter.are in body-assembled relation; and it will be understood ~hat coils 86-86' are preferably electrically . .
connected in parallel~ in flux-aiding polarity; being exci-ted b~ one or the other of the ener~izing circuits o~ Figs~ 4 and 5. .
Xn addition to the described coil-positioning and foot-suppor~ing structure, the device of Fig. 11 includes side-bumper guards 87-88 ~hich may be bowed strips of the same pla~tic material as shel~ 80, suitably bonded at hoth ends to ~he respecti~e longituainal ends of shell B0~ Strips 87-88 are prcferably stiffly yieldable, to cushion the treated region - -32- .

1157~
fro~ mecr.anical shoc~ in ~he event o~ un-~itting contact witn furni-ture or other objects.
Fig. 12 is a simplifled dia~rt~m similar to Fig. 11 to illust~ate ano~her body-treatment device, configurated for ap?lication to an af~licted ankle region, or to a lower tibia/~emur region. Again, the basic riyid structure is seen LO com~rise a tubular shell 90, as of suitable plastic.
A single local side-wall opening 91 in shell 90 has a straight lo-.~er edge, contiguous -to a bottom plate or rest 92 which diametrically spc~ns .the`lower end oE shell 90. ~pposed electrical coils 93~94 are bonded to the inner sur~ace o~ .
shell 90 a L an e.~evation suc~ that the alignment 95 of their centers OL symmetry ~ill geometrically intersect -the center . OL the aLlicted region, preferably as con~irmed by X-ray observation on the alignment 95. The configuration o coils ~3-9~ may be circular or elliptical, but is preferably cylindrically arcuate, in con~armance with the loca- shell ~urface to which each of them is bonded; in the event o elli~tical coil conigurations, the major-axis orien-tation is preLerably vertical, consistent with the discussion above as to coils S8 in Fig. 7. Interconnection and excitation o~ .
coils 93-9~ is as described for other two-coil devices.
It ~Jill 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~ ~lith respect to the body~treatment devices hich have been desGribed, we have not yet established -the full range of di~ensional limi-tations, but certain beneicial ranges can be described in general terms, particularly for dual-coil e~bodime~ts, illus-tratively disclosed in connection wi-th Figs.
7 to 12.

11575~7 On an elemental basis, it is convenient to consider the circular~coil situation depicted in Fig. 13, wherein li~c circular coils ~-~ of inside diameter Dl are positioned on a co~non central axis of symmetry, at parallel p].anes which are spaced apart b~ the distance S, and wherein the coils A-B are e~ci-ted in flux-aiding relation. If the . .
spacing S is sufficiently small .in relation to the diame-ter Dl, then substantially all flu~ lines within coils ~-B will extend continuously therebetween, on a ~enerally straight alignment whicll may even neck down as suggested by the profile 96. If the spaoi~c~ S is greater (again in relation to the diame~er Dll, some stray-flux lines 97 will develop, to ~ e detriment of the development of uniform hlgh-density flux in -the central span S. Generally, in view of the necking down .15 (96~, and in v.ie~ o~ the treabment ~one being genexally at the center of span S, it is convenient to ~onsider the coils A-B as being desirably effective in producing the un~form ~lux distrl~ution 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 applica-tion of the ch~rac~er presently described, the span S.should.be equal to ox less than ~he diameter Dl, and o~ course D2 (the efEec-ti~e diameter o~ ~he zone of body treatment~ will always be considerably less than Dl, being substantially e~ual 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 ~2 of the ef~ective bod~-treatment zone, and this has been found to be a reliable approach for coil spacin~ S substan-tially equal to the inside diameter Dl.

-34-.

1 1~7527 }laving thus conaidered criteria factors for the simplified case of flat circular coils, it is possible to develop general criteria applic~bl~ to elliptical coils which ,are "wrapped" in general con-~ormance,with .
a cylindrical arc. Fig. la schematically depic~s the - coil-58 relationship discussed for Fig. 7, wherein the -, c~lindrical arc oE "wrapped" coil curvature is about a central axis lO0, which is paxallel to the majox a~Yis of the coil ellipse. And Fig. 15 schematicaily depicts a , coil~5~' relationship.whexein the cylindrically arcuate curv~ture of ~he coils is parallel to the minor axis of each coil. In bo-th cases, the typical resultant treat-ment zone sec-tion is sugge5ted by aashed outline in the ront vie~ tr~ig. l4a and Fig. 15a).
. 15For purposes of deducing central magnetic-fiela distr;bution between opposed coils 58, their major-axis . . re~ionsi (designated p-q-p'-q' in Fig. 7~ ma~ be aeemed to.
be at maximum separation Sl and their minor-axis regions, ~designated m-n-m'-n' in Fig., 72 ma~ be deemed to be a~ ,, ~20 minimum separcation S2r as viewed in Fig. 14b. :This being ;the case, ma30r-axis-region contributions to the magne~ic field may be deemed-to-appl-y Eor the span S (of Fig. 13) e~ual to Sl (of Fi~. 14b) in the context o:E an effective inside diameter Dmaj which corresponds to the major axis of the ellipse; by the same toXen, minor-axis-region contri-butions to the magnetic field may be deemed to apply~for a span.S~ lo~ Fig. 15~) in the context.o~ an effective inside diameter Dmin ~hich corresponds to the minor axis of the ellipse. For sectional considerations at planes intermediate those of the major axes and of the minor axes/ the field ~ill.
.
.

1 1575~7 ollow distribution considerations intermediate those controlling distribution in planes o~ the major axes and of thc minor axes, respectively.
Reasoning applied above as to maynetic-~ield distribution for -the ~ig. 1~ configuration can also be applied to that of Fig. 15 r e~cept of course ~hat patterns `Jill difer by reason of the cylindxical curvature about an axis parallel to the minor ellip-tical axis.
The arrallCJement of Fig. 16 depicts use of t~o gener~lly cylincir:ic~ arcua-te coils 58" trherein the c~lindrical arc3 ~re nes'ted in spaced relation appropriate to the des'ired ~plication, electrical connection being again understooc1 to be or flux-aiding. The coil arrangement of Fig. 16 will }~ ~mderstood to have appllcation over a genexally cylinc~rically arcuate treatment zone, as in the case of a ~aw segment or group of teeth, the latter heing su~gested schematically at 101 in Fig. 16b. Depending upon ~he size o~ coils 58", it will be understood that they may be retained in fixed spacing, using a suitable bracket (suggested at 102~ ~hic~ bridges onl~ teeth in the case of ' insertion of both'coils in the mouth, and which bridges -teeth as well as the` adjacent cheek (via the mou-th~' in the case o~
one coil inside and the other coil outside the mouth. It will also be understood t~at for purposes of certain desired ~lux distribution within the mouth, as for dental and/or jaw osteogenesis, the inner coil 58" may be of smaller physical size ~han the outer coil 58".
It will be understood that the foregoing discussion of general principles is with a view to illustration and n~t limitation, and that modifications may be made without de~arting 1 1 ~7527 from the scope of the invention. For example, if for certain purposes, it is not possible -to construct bo-th coils of a dual-coil e~bodiment so as to completely,match in ~eometr~ and electrical properties, as suggested above for a dental or ja~ application, there can still be a useful em~loyment of the` invention, using magnetic-flux distxibution ~.
hich may not be as uniform as discussed in connection with ,.
Fiss. 13 to 16, but whi'ch nevertheless,derives benefit from the fl~L~:-aidincJ cooperation of' tt~o colls in opposite sides o. the afflicte~l regio.n under treatment, such benefit flowing of course from the~ e~citation of such'coils by the specially characterized inp~lts discussed in connection with Figs. 4 to G.
Figs. 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 treatea. ~n ~ig. 17,.a sin~le coil of like plural turns 105 is helically developed along the length of a supporting tubulax member 106 of sui-table pIastic or other non-magnetic material.
20 .The turns 105 may be on the inner or the outer surface o tube 106, and the axial length of the w;nding should be such as to overlap both longituainal ends of the bone fracture or the like' to be treated.
In Fig. 18, a single winding is again shown carried by one of the c~lindrical surfaces of a ~ubular member 108, but the latter is locall~ cut at an opening 109 (as in the manner described at 81 in Fig.. 11) tQ permit insertion of a joint region such as the elbow, with the forearm projecting out one axial end of tubular member 108, and with -the upper arm pro-jecting xadially out~ard via opening lO9. The single wind~ng' q . . .

I :l57527 is sho~.n as a firs~ plurality 110 oE helical -turns contin-uousl~f connect~d b~ an axially e~panded t~rn 111 to a s~cond plurality 112 of similar turns, the pluralities 110-112 being posi~ioned on opposite longitudinal sides of the opening 109 and at a spacing which is a-t least no greater -than the effective diameter of the turns 110-112.
T'ne arran~ement of Fig. 19 is similar to that of Fig. 18 excep~ that the respective pluralities of turns 110-112 are electricall~ connected in parallel, in flux-aiding relation.
~ central acccss port ~ill be ~mderstood -to be provided in ' , tubular member 108 at a location opposite the opening 109, to perm~t excitation ~ir~ng connections to be provided external to all turns, i.~, no supply lines passing within any of the , turns at 110~112.
In the arrallclement Q~ Fig. 20, two coil subassemblies 115-116 are cons~ructed for assembly to'the,respective ends of a longitudinall~ split compliant-supporting me~ber 117 of non-magnetic material. The lonyitudinal split at 118 permits a degree of-flexibility in apPlication to a body me~berr as for example durin~ the course of its assembly past the heel ' region to a leg part to be treated. Each of -the coil sub-assemblies is shown to be'a relatively rigid annular assembly of a winding to apotting o~ 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 de~ines an inward flange to limit coil assembly, a~d to determine repeatably accurate spaced retention of the t~lo coil subassemblies. Electrical connections to the coil sub-

3~ assemblies are sho~n to be parallel, and should be in flux-1 ~7~27 ai~ing relation, and a f-lexible-cable interconnection is sug~ested at 12~.
It ~-ill be understood that various simplifyiny techniques have been adopted to make for more readily understood reference to the dra~7ings. For example, in the riyid-frame coil-supporting embodlments of Fig5. 11, 12, and 17 to 20, it will be unders-tood that in application to the bod~ certain cushioning liner materials such as urethane IOam are preferably adhered to the described structure for cc~m:Eol^ta~le enga~ement with the body at the region of application, bu-t to have shown such liners would only encumber the.d.rawings. Also, in connection wi~h Fig. 9, the showing of tlle cast 71 is merely illustrative, in that the key device 65 may be othen~ise e~ternally mounted, as for example to an exl:ernal fixation device such as a puttee, or to the bod~ limb itself ~i.e., without a cast, as in.latter stages of a bone repairl, and the cast may be of materials 18 oth_r th-n plas~_r, e.g., the ~tB~isl h~owr as crthoplas_.

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Claims (30)

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

1. 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 two multi-turn electrical coils and body-adapting retaining means adapted to mount said coils in spaced relation on opposite sides of an afflicted body region to be treated, said coils when thus mounted having turns about a flux-development axis through the afflicted body region and being connected in flux-aiding relation, said turns being radially spaced from said axis to an extent establishing an effective local diameter which substantially equals or exceeds the effective axial spacing between said coils, and means for electrically exciting said coils with a succession of low-voltage unidirectional asymmetrical pulses.

2. The treatment device of claim 1, in which said retaining means com-prises strap means adapted for circumferential wrap of the afflicted body region, said coils being mounted to and along said strap means in spaced relation such as to position said coils on opposite sides of the body-treat-ment region when said strap means is in circumferentially wrapped application to the body.

3. The treatment device of claim 2, in which said strap means is flex-ible and includes means for selectively adjusting the strap-connected span between said coils.

4. The treatment device of claim 3, in which said strap means is of length extending beyond the adjustably connected span in an amount at least sufficient for full circumferential envelopment of said adjustably connected span, and selectively operable means for securing said strap means in the position of such circumferential envelopment.

5. The treatment device of claim 1, in which at least one of said coils is of generally elliptical configuration.

6. The treatment device of claim 5, in which said elliptical coil is developed in essentially a single surface which is generally cylindrically arcuate.

7. The treatment device of claim 6, in which the arcuate curvature is about an axis generally parallel to the major axis of the ellipse.

8. The treatment device of claim 6, in which the arcuate curvature is about an axis generally parallel to the minor axis of the ellipse.

9. The treatment device of claim 1, in which both of said coils are of generally elliptical configuration, and in which said retaining means positions the major-axis orientation of said coils in generally parallel relation.

10. The treatment device of claim 9, in which each of said coils is developed in essentially a single surface which is cylindrically arcuate, said retaining means being adapted to position the concave sides of the respective coils in face-to-face relation across the afflicted region.

11. The treatment device of claim 9, in which each of said coils is developed in essentially a single surface which is cylindrically arcuate about an axis which is generally parallel to the major axis of its ellipse, said retaining means being adapted to position the major axes in generally parallel relation.

12. The treatment device of claim 9, in which each of said coils is developed in essentially a single surface which is cylindrically arcuate about an axis which is generally parallel to the minor axis of its ellipse, said retaining means being adapted to position the minor axes in generally parallel relation.

13. The treatment device of claim 9, in which each of said coils is developed in essentially a single surface which is cylindrically arcuate, said retaining means being adapted to position the concave sides of the respective coils in nested relation, with the concave side of one coil facing the convex side of the other coil across the afflicted region.

14. The treatment device of claim 1, in which both said coils are of generally helical configuration, the helical advance of both coils being in the same direction.

15. The treatment device of claim l, in which each of said coils com-prises plural generally helically advancing turns in the same direction.

16. The treatment device of claim l, in which said coils are electrically connected in parallel.

17. The treatment device of claim l, in which said coils are electrically connected in series.

18. The treatment device of claim 1, in which said retaining means comprises a rigid tubular frame member with said respective coils rigidly mounted to said frame member at opposed locations, the wall of said frame member being locally open within the region of mounting one of said coils, whereby a body member having the afflicted region may be removably entered into said frame member and pass through the frame opening to place the afflicted region in the treatment zone of said coils.

19. The treatment device of claim 1, in which said retaining means com-prises a rigid tubular frame member with said respective coils rigidly mounted to said frame member at spaced locations, the wall of said frame member being locally open in a region intermediate the mounting of said coils, whereby a body member having the afflicted region may be removably entered into said frame member and pass through the frame opening to place the afflicted region in the treatment zone of said coils.

20. The treatment device of claim 1, in which said retaining means for at least one of said coils includes 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 one coil being located by and within said casing and in adjacency to said front surface, said surface having a keying recess formed therein, the peripheral edge of said recess extending symmetrically about the central axis of said one coil, and a separate key element conforming to and re-movably insertable in said recess, said key element having laterally exten-ding adapter means for relatively fixed location of said key element with respect to the body to be treated, whereby once correctly located and fixed with respect to the body, said key element will accurately determine the location of said one coil upon assembly of the surface recess thereto, so that said retaining means can then correctly reference both coils to the body-treatment region, for repeated application and removal of said coils with respect to the body.

21. The treatment device of claim 20, in which said key element includes radiologically opaque frame-marking means at peripheral edges of said key element.

22. The treatment device of claim 21, in which said frame-marking means includes a strip of metal tape removably adhered to the peripheral edge of said key element.

23. The treatment device of claim 1, in which said retaining means for at least one of said coils includes 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 one 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 one coil, and a removably positionable locating element having a surface formation which conforms to and is interengageable with said key formation, said locating element having laterally extending adapter means for relatively fixed loca-tion of said location elements with respect to the body to be treated, where-by once correctly located and fixed with respect to the body, said locating element will accurately determine the location of said one coil upon assembly of said key formation thereto, so that said retaining means can then correct-ly reference both said coils to the body-treatment region, for repeated ap-plication and removal of said coils with respect to the body.

24. An electromagnetic body-treatment device for surgically non-inva-sive modification of the growth, repair and maintenance behavior of living tissues and cells by a specific and selective change in electrical environ-ment, comprising two multi-turn electrical coils of generally circular con-figuration and body-adapting retaining means adapted to mount said coils in spaced relation on opposite sides of an afflicted body region to be treated, said coils when thus mounted having turns about a flux-development axis through the afflicted body region and being connected in flux-aiding rela-tion, said turns being radially spaced from said axis to an extent establish-ing an effective local diameter which substantially equals or exceeds the ef-fective axial spacing between said coils, and means for electrically exciting said coils with a succession of low-voltage unidirectional asymmetrical pulses.

25. The treatment device of claim 24, in which both said coils are of generally circular helical configuration, the helical advance of both coils being along the same axis.

26. The treatment device of claim 24, in which each of said coils comprises plural helically advancing turns along the same axis.

27. The treatment device of claim 24, in which said coils are elec-trically connected in parallel.

28. The treatment device of claim 24, in which said coils are elec-trically connected in series.

29. The treatment device of claim 24, in which said retaining means comprises a rigid tubular frame member with said respective coils rigidly mounted to said frame member at diametrically opposed locations, the wall of said frame member being locally open within the region of mounting one of said coils, whereby a body member having the afflicted region may be remov-ably entered into said frame member and pass through the frame opening to place the afflicted region in the treatment zone of said coils.

30. The treatment device of claim 24, in which said retaining means comprises a rigid tubular frame member with said respective coils rigidly mounted to said frame member at axially spaced locations, the wall of said frame members being locally open in a region intermediate the mounting of said coils, whereby a body member having the afflicted region may be remov-ably entered into said frame member and pass through the frame opening to place the afflicted region in the treatment zone of said coils.