1111111111111111 IIIIII IIIII 1111111111 11111 111111111111111 1111111111 111111111111111 11111111
`US 20110125203Al
`
`c19) United States
`c12) Patent Application Publication
`Simon et al.
`
`c10) Pub. No.: US 2011/0125203 Al
`May 26, 2011
`(43) Pub. Date:
`
`(54) MAGNETIC STIMULATION DEVICES AND
`METHODS OF THERAPY
`
`(75)
`
`Inventors:
`
`Bruce Simon, Mountain Lakes, NJ
`(US); Joseph P. Errico, Warren, NJ
`(US); John T. Raffle, Austin, TX
`(US)
`
`(73) Assignee:
`
`ElectroCore, LLC., Morris Plains,
`NJ (US)
`
`(21) Appl. No.:
`
`12/964,050
`
`(22) Filed:
`
`Dec. 9, 2010
`
`Related U.S. Application Data
`
`(63) Continuation-in-part of application No. 12/859,568,
`filed on Aug. 19, 2010, which is a continuation-in-part
`of application No. 12/408,131, filed on Mar. 20, 2009.
`
`(60) Provisional application No. 61/415,469, filed on Nov.
`19, 2010.
`
`Publication Classification
`
`(51)
`
`Int. Cl.
`A61N 1136
`(2006.01)
`(52) U.S. Cl. ............................................................ 607/2
`ABSTRACT
`(57)
`
`Devices and systems are disclosed for the non-invasive treat(cid:173)
`ment of medical conditions through delivery of energy to
`target tissue, comprising a source of electrical power, a mag(cid:173)
`netically permeable toroidal core, and a coil that is wound
`around the core. The coil and core are embedded in a con(cid:173)
`tinuous electrically conducting medium, which is adapted to
`have a shape that conforms to the contour of an arbitrarily
`oriented target body surface of a patient. The conducting
`medium is applied to that surface by any of several disclosed
`methods, and the source of power supplies a pulse of electric
`charge to the coil, such that the coil induces an electric current
`and/or an electric field within the patient, thereby stimulating
`tissue and/or one or more nerve fibers within the patient. The
`invention shapes an elongated electric field of effect that can
`be oriented parallel to a long nerve. In one embodiment, the
`device comprises two toroidal cores that lie adjacent to one
`another.
`
`NS Device- 300
`
`lmpu!se
`Generator
`3·10
`
`Control
`Unit
`330
`
`PO\ver
`Source
`320
`
`LUMENIS EX1049
`Page 1
`
`

`

`Patent Application Publication
`
`May 26, 2011 Sheet 1 of 9
`
`US 2011/0125203 Al
`
`FIG. 1
`
`NS Device 300
`
`lmpu!se
`Generator
`3'10
`
`Control
`Unit
`33-0
`
`Po\ver
`Source
`32:0
`
`FIG. 2
`
`400
`
`Activity
`
`Current
`
`Time
`
`410
`
`\
`
`f
`
`/
`
`420
`
`Current
`
`Time
`
`LUMENIS EX1049
`Page 2
`
`

`

`Patent Application Publication May 26, 2011 Sheet 2 of 9
`
`US 2011/0125203 Al
`
`FIG.3A
`
`FIG. 3B
`
`30
`
`FIG.3C
`
`30
`
`FIG. 3D
`
`30
`
`34
`
`34
`
`33
`
`LUMENIS EX1049
`Page 3
`
`

`

`Patent Application Publication May 26, 2011 Sheet 3 of 9
`
`US 2011/0125203 Al
`
`FIG.4.A
`
`FIG.4D
`
`FIG.4E
`
`LUMENIS EX1049
`Page 4
`
`

`

`Patent Application Publication May 26, 2011 Sheet 4 of 9
`
`US 2011/0125203 Al
`
`FIG. 5
`
`30
`
`:39
`
`l--38
`
`LUMENIS EX1049
`Page 5
`
`

`

`Patent Application Publication May 26, 2011 Sheet 5 of 9
`
`US 2011/0125203 Al
`
`FIG. 6
`
`-----==----=i.---------- 7 5
`----=--,-------a"t---------"k-- 7 6
`---,JL------ 77
`
`30
`
`LUMENIS EX1049
`Page 6
`
`

`

`Patent Application Publication May 26, 2011 Sheet 6 of 9
`
`US 2011/0125203 Al
`
`FIG. 7
`
`66 67 68
`
`76
`
`LUMENIS EX1049
`Page 7
`
`

`

`Patent Application Publication May 26, 2011 Sheet 7 of 9
`
`US 2011/0125203 Al
`
`FIG. 8
`
`82---+--
`
`30
`
`LUMENIS EX1049
`Page 8
`
`

`

`Patent Application Publication May 26, 2011 Sheet 8 of 9
`
`US 2011/0125203 Al
`
`FIG. 9
`
`0
`
`30
`
`LUMENIS EX1049
`Page 9
`
`

`

`Patent Application Publication May 26, 2011 Sheet 9 of 9
`
`US 2011/0125203 Al
`
`FIG. ·10
`
`30
`
`103
`
`102
`
`101-
`
`100
`
`a
`
`.....
`
`LUMENIS EX1049
`Page 10
`
`

`

`US 2011/0125203 Al
`
`May 26, 2011
`
`1
`
`MAGNETIC STIMULATION DEVICES AND
`METHODS OF THERAPY
`
`CROSS REFERENCE TO RELATED
`APPLICATIONS
`
`[0001] This application claims the benefit of priority of
`U.S. Provisional Patent Application No. 61/415,469 filed
`Nov. 19, 2010. This application is a continuation-in-part of
`co-pending U.S. patent application Ser. No. 12/859,568 filed
`Aug. 9, 2010 which is a continuation-in-part application of
`co-pending U.S. patent application Ser. No. 12/408,131,
`titled Electrical Treatment of Bronchial Constriction, filed
`Mar. 20, 2009, the entire disclosure of which is hereby incor(cid:173)
`porated by reference.
`
`BACKGROUND OF THE INVENTION
`
`[0002] The field of the present invention relates to the deliv(cid:173)
`ery of energy impulses (and/or fields) to bodily tissues for
`therapeutic purposes. It relates more specifically to toroidal
`magnetic stimulation devices, as well as to non-invasive
`methods for treating medical conditions using energy that is
`delivered by such devices. The medical conditions include,
`but are not limited to, post-operative ileus, neurodegenerative
`disorders (such as Alzheimer's disease), post-operative cog(cid:173)
`nitive dysfunction (POCD), post-operative delirium (POD),
`dementia, rheumatoid arthritis, acute and chronic depression,
`epilepsy, Parkinson's disease, multiple sclerosis (MS), bron(cid:173)
`choconstriction associated with asthma, anaphylaxis or
`COPD, sepsis or septic shock, hypovolemia or hypovolemic
`shock, orthostatic hypotension, hypertension, urinary incon(cid:173)
`tinence and/or overactive bladder, and sphincter of Oddi dys(cid:173)
`function.
`[0003] Treatments for various infirmities sometime require
`the destruction of otherwise healthy tissue in order to produce
`a beneficial effect. Malfunctioning tissue is identified and
`then lesioned or otherwise compromised in order to produce
`a beneficial outcome, rather than attempting to repair the
`tissue to its normal functionality. A variety of techniques and
`mechanisms have been designed to produce focused lesions
`directly in target nerve tissue, but collateral damage is inevi(cid:173)
`table.
`[0004] Other treatments for malfunctioning tissue can be
`medicinal in nature, but in many cases the patients become
`dependent upon artificially synthesized chemicals. Examples
`of this are anti-asthma drugs such as albuterol, proton pump
`inhibitors such as omeprazole (Prilosec ), spastic bladder
`relievers such as Ditropan, and cholesterol reducing drugs
`such as Lipitor and Zocor. In many cases, these medicinal
`approaches have side effects that are either unknown or quite
`significant. For example, at least one popular diet pill of the
`late 1990's was subsequently found to cause heart attacks and
`strokes. Unfortunately, the beneficial outcomes of surgery
`and medicines are often realized at the cost of function of
`other tissues, or risks of side effects.
`[0005] The use of electrical stimulation for treatment of
`medical conditions has been well known in the art for nearly
`two thousand years. It has been recognized that electrical
`stimulation of the brain and/or the peripheral nervous system
`and/or direct stimulation of the malfunctioning tissue holds
`significant promise for the treatment of many ailments,
`because such stimulation is generally a wholly reversible and
`non-destructive treatment.
`
`[0006] Nerve stimulation is thought to be accomplished
`directly or indirectly by depolarizing a nerve membrane,
`causing the discharge of an action potential; or by hyperpo(cid:173)
`larization of a nerve membrane, preventing the discharge of
`an action potential. Such stimulation may occur after electri(cid:173)
`cal energy, or also other forms of energy, are transmitted to the
`vicinity of a nerve [F. RATTAY. The basic mechanism for the
`electrical stimulation of the nervous system. Neuroscience
`Vol. 89, No. 2, pp. 335-346, 1999; Thomas HEIMBURG and
`Andrew D. Jackson. On soliton propagation in biomem(cid:173)
`branes and nerves. PNAS vol. 102 (no. 28, Jul. 12, 2005):
`9790-9795]. Nerve stimulation may be measured directly as
`an increase, decrease, or modulation of the activity of nerve
`fibers, or it may be inferred from the physiological effects that
`follow the transmission of energy to the nerve fibers.
`[0007] Electrical stimulation of the brain with implanted
`electrodes has been approved for use in the treatment of
`various conditions, including pain and movement disorders
`such as essential tremor and Parkinson's disease. The prin(cid:173)
`ciple underlying these approaches involves disruption and
`modulation of hyperactive neuronal circuit transmission at
`specific sites in the brain. Unlike potentially dangerous
`lesioning procedures in which aberrant portions of the brain
`are physically destroyed, electrical stimulation is achieved by
`implanting electrodes at these sites. The electrodes are used
`first to sense aberrant electrical signals and then to send
`electrical pulses to locally disrupt pathological neuronal
`transmission, driving it back into the normal range of activity.
`These electrical stimulation procedures, while invasive, are
`generally conducted with the patient conscious and a partici(cid:173)
`pant in the surgery.
`[0008] Brain stimulation, and deep brain stimulation in par(cid:173)
`ticular, is not without some drawbacks. The procedure
`requires penetrating the sknll, and inserting an electrode into
`brain matter using a catheter-shaped lead, or the like. While
`monitoring the patient's condition (such as tremor activity,
`etc.), the position of the electrode is adjusted to achieve sig(cid:173)
`nificant therapeutic potential. Next, adjustments are made to
`the electrical stimulus signals, such as frequency, periodicity,
`voltage, current, etc., again to achieve therapeutic results. The
`electrode is then permanently implanted, and wires are
`directed from the electrode to the site of a surgically
`implanted pacemaker. The pacemaker provides the electrical
`stimulus signals to the electrode to maintain the therapeutic
`effect. While the therapeutic results of deep brain stimulation
`are promising, there are significant complications that arise
`from the implantation procedure, including stroke induced by
`damage to surrounding tissues and the neuro-vasculature.
`[0009] One of the most successful applications of modem
`understanding of the electrophysiological relationship
`between muscle and nerves is the cardiac pacemaker.
`Although origins of the cardiac pacemaker extend back into
`the 1800's, it was not until 1950 that the first practical, albeit
`external and bulky, pacemaker was developed. The first truly
`functional, wearable pacemaker appeared in 1957, and in
`1960, the first fully implantable pacemaker was developed.
`[0010] Around this time, it was also found that electrical
`leads could be connected to the heart through veins, which
`eliminated the need to open the chest cavity and attach the
`lead to the heart wall. In 1975 the introduction of the lithium(cid:173)
`iodide battery prolonged the battery life of a pacemaker from
`a few months to more than a decade. The modem pacemaker
`can treat a variety of different signaling pathologies in the
`cardiac muscle, and can serve as a defibrillator as well (see
`
`LUMENIS EX1049
`Page 11
`
`

`

`US 2011/0125203 Al
`
`May 26, 2011
`
`2
`
`U.S. Pat. No. 6,738,667 to DENO, et al., the disclosure of
`which is incorporated herein by reference).
`[0011] Another application of electrical stimulation of
`nerves has been the treatment of radiating pain in the lower
`extremities by stimulating the sacral nerve roots at the bottom
`of the spinal cord (see U.S. Pat. No. 6,871,099 to WHITE(cid:173)
`HURST, et al., the disclosure of which is incorporated herein
`by reference).
`[0012] The present disclosure involves devices and medical
`procedures that stimulate nerves by transmitting energy to
`nerves and tissue non-invasively. A medical procedure is
`defined as being non-invasive when no break in the skin (or
`other surface of the body, such as a wound bed) is created
`through use of the method, and when there is no contact with
`an internal body cavity beyond a body orifice ( e.g, beyond the
`mouth or beyond the external auditory meatus of the ear).
`Such non-invasive procedures are distinguished from inva(cid:173)
`sive procedures (including minimally invasive procedures) in
`that invasive procedures do involve inserting a substance or
`device into or through the skin or into an internal body cavity
`beyond a body orifice.
`[0013] Potential advantages of such non-invasive medical
`methods and devices relative to comparable invasive proce(cid:173)
`dures are as follows. The patient may be more psychologi(cid:173)
`cally prepared to experience a procedure that is non-invasive
`and may therefore be more cooperative, resulting in a better
`outcome. Non-invasive procedures may avoid damage of bio(cid:173)
`logical tissues, such as that due to bleeding, infection, skin or
`internal organ injury, blood vessel injury, and vein or lung
`blood clotting. Non-invasive procedures are sometimes pain(cid:173)
`less or only minimally painful and may be performed without
`the need for even local anesthesia. Less training may be
`required for use of non-invasive procedures by medical pro(cid:173)
`fessionals. In view of the reduced risk ordinarily associated
`with non-invasive procedures, some such procedures may be
`suitable for use by the patient or family members at home or
`by first-responders at home or at a workplace, and the cost of
`non-invasive procedures may be reduced relative to compa(cid:173)
`rable invasive procedures.
`[0014] For example, transcutaneous electrical nerve stimu(cid:173)
`lation (TENS) is non-invasive because it involves attaching
`electrodes to the surface of the skin (or using a form-fitting
`conductive garment) without breaking the skin. In contrast,
`percutaneous electrical stimulation of a nerve is minimally
`invasive because it involves the introduction of an electrode
`under the skin, via needle-puncture of the skin. Both TENS
`and percutaneous electrical stimulation can be to some extent
`unpleasant or painful, in the experience of patients that
`undergo such procedures. In the case of TENS, as the depth of
`penetration of the stimulus under the skin is increased, any
`pain will generally begin or increase.
`[0015] The form of non-invasive electrical stimulation with
`which the present application is primarily concerned is mag(cid:173)
`netic stimulation. It involves the induction, by a time-varying
`magnetic field, of electrical fields and current within tissue, in
`accordance with Faraday's law ofinduction. Magnetic stimu(cid:173)
`lation is non-invasive because the magnetic field is produced
`by passing a time-varying current through a coil positioned
`outside the body, inducing at a distance an electric field and
`electric current within electrically-conducting bodily tissue.
`Because the induced electric field and induced current depend
`not only upon current being passed through wire of the coil,
`but also upon the permeability of core material around which
`
`the coil may be wound, the term coil as used herein refers not
`only to the current-carrying wire, but also to the core material,
`unless otherwise indicated.
`[0016] Large, pulsed magnetic fields (PMF) can induce
`significant electric fields in conducting media, including
`human tissue. Particular waveforms and amplitudes can
`stimulate action potentials in nerves, both in vitro and in vivo.
`Due to the noninvasive nature of the stimulation, PMF
`devices have found utility in several clinical applications,
`both therapeutically, e.g., for treating depression via transc(cid:173)
`ranial magnetic stimulation (TMS), and diagnostically, for
`peripheral nerve stimulation. It is an objective of the present
`invention to use magnetic stimulation to produce significantly
`less pain or discomfort, as compared with that experienced by
`the patient undergoing a treatment with TENS, for a given
`depth of stimulus penetration. Or conversely, for a given
`amount of pain or discomfort on the part of the patient (e.g.,
`the threshold at which such discomfort or pain begins), an
`objective of the present invention is to achieve a greater depth
`of penetration of the stimulus under the skin.
`[0017] The principle of operation of magnetic stimulation,
`along with a description of commercially available equip(cid:173)
`ment and a list of medical applications of magnetic stimula(cid:173)
`tion, is reviewed in: Chris HOVEY and Reza Jalinous, The
`Guide to Magnetic Stimulation, The Magstim Company Ltd,
`Spring Gardens, Whitland, Carmarthenshire, SA34 OHR,
`United Kingdom, 2006. The types of the magnetic stimulator
`coils that are described there include circular, parabolic, fig(cid:173)
`ure-of-eight (butterfly), and custom designs. Additional types
`of the magnetic stimulator coils are described in U.S. Pat. No.
`6,179,770, entitled Coil assemblies for magnetic stimulators,
`to MOULD; as well as in Kent DAVEY. Magnetic Stimula(cid:173)
`tion Coil and Circuit Design. IEEE Transactions on Biomedi(cid:173)
`cal Engineering, Vol. 47 (No. 11, November 2000): 1493-
`1499 and in HSU K H, Nagarajan S S, Durand D M. Analysis
`of efficiency of magnetic stimulation. IEEE Trans Biomed
`Eng. 2003 November; 50 (11):1276-85.
`[0018] The circuits that are used to send pulses or other
`waveforms through magnetic stimulator coils are also
`described by HOVEY and Jalinous in The Guide to Magnetic
`Stimulation that was cited above. Custom magnetic stimula(cid:173)
`tor circuits for control, impulse generator and power supply
`have also been described [Eric BASHAM, Zhi Yang, Natalia
`Tchemodanov, and Wentai Liu. Magnetic Stimulation of
`Neural Tissue Techniques and System Design. pp 293-352,
`In: Implantable Neural Prostheses 1, Devices and Applica(cid:173)
`tions, D. Zhou and E. Greenbaum, eds., New York: Springer
`(2009); U.S. Pat. No. 7,744,523, entitled Drive circuit for
`magnetic stimulation, to EPSTEIN; U.S. Pat. No. 5,718,662,
`entitled Apparatus for the magnetic stimulation of cells or
`tissue, to JANILOUS; U.S. Pat. No. 5,766,124, entitled Mag(cid:173)
`netic stimulator for neuro-muscular tissue, to POLSON].
`[0019] As described in the above-cited publications, the
`circuits for magnetic stimulators are generally complex and
`expensive. They use a high current impulse generator that
`may produce discharge currents of 5,000 amps or more,
`which is passed through the stimulator coil, and which
`thereby produces a magnetic pulse. Typically, a transformer
`charges a capacitor in the impulse generator, which also con(cid:173)
`tains circuit elements that limit the effect of undesirable elec(cid:173)
`trical transients. Charging of the capacitor is under the control
`of a control unit, which accepts information such as the
`capacitor voltage, power and other parameters set by the user,
`as well as from various safety interlocks within the equipment
`
`LUMENIS EX1049
`Page 12
`
`

`

`US 2011/0125203 Al
`
`May 26, 2011
`
`3
`
`that ensure proper operation, and the capacitor is then dis(cid:173)
`charged through the coil via an electronic switch ( e.g., a
`controlled rectifier) when the user wishes to apply the stimu(cid:173)
`lus. Greater flexibility is obtained by adding to the impulse
`generator a bank of capacitors that can be discharged at dif(cid:173)
`ferent times. Thus, higher impulse rates may be achieved by
`discharging capacitors in the bank sequentially, such that
`recharging of capacitors is performed while other capacitors
`in the bank are being discharged. Furthermore, by discharg(cid:173)
`ing some capacitors while the discharge of other capacitors is
`in progress, by discharging the capacitors through resistors
`having variable resistance, and by controlling the polarity of
`the discharge, the control unit may synthesize pulse shapes
`that approximate an arbitrary function.
`[0020] Another practical disadvantage of magnetic stimu(cid:173)
`lator coils is that they overheat when used over an extended
`period of time, because large coil currents are required to
`reach threshold electric fields in the stimulated tissue. At high
`repetition rates, currents can heat the coils to unacceptable
`levels in seconds to minutes, depending on the power levels
`and pulse durations and rates. Accordingly, coil-cooling
`equipment is used, which adds complexity to the magnetic
`stimulator coils. Two approaches to overcome heating are to
`cool the coils with flowing water or air or to increase the
`magnetic fields using ferrite cores (thus allowing smaller
`currents). For some applications where relatively long treat(cid:173)
`ment times at high stimulation frequencies may be required,
`e.g. treating asthma by stimulating the vagus nerve, neither of
`these two approaches may be adequate. Water-cooled coils
`overheat in a few minutes. Ferrite core coils heat more slowly
`due to the lower currents and heat capacity of the ferrite core,
`but they also cool slowly and do not allow for water-cooling
`because the ferrite core occupies the volume where the cool(cid:173)
`ing water would flow. One solution to this problem is to use a
`core that contains ferrofluids [U.S. Pat. No. 7,396,326 and
`published applications US20080114199, US20080177128,
`and US20080224808, all entitled Ferrofluid cooling and
`acoustical noise reduction in magnetic stimulators, respec(cid:173)
`tively to GHIRON et al., RIEHL et al., RIEHL et al. and
`GHIRON et al.]. However, even the use of ferrofluids may be
`inadequate when long treatment times at high stimulation
`frequencies may be required.
`[0021] Another problem that is sometimes encountered
`during magnetic stimulation is the unpleasantness or pain that
`is experienced by the patient in the vicinity of the stimulated
`tissue. Little is known about the mechanism that produces the
`pain, although it is generally recognized that magnetic stimu(cid:173)
`lation produces less pain than its electrode-based counterpart.
`Most investigations that address this question examine pain
`associated with transcranial stimulation.
`[0022] ANDERSON et al found that when magnetic stimu(cid:173)
`lation is repeated over the course of multiple sessions, the
`patients adapt to the pain and exhibit progressively less dis(cid:173)
`comfort [Berry S. ANDERSON, Katie Kavanagh, Jeffrey J.
`Borckardt, Ziad H. Nahas, Samet Kase, Sarah H. Lisanby,
`William M. McDonald, DavidAvery, Harold A. Sackeim, and
`Mark S. George. Decreasing Procedural Pain Over Time of
`Left Prefrontal rTMS for Depression: Initial Results from the
`Open-Label Phase of a Multisite Trial (OPT-TMS). Brain
`Stimul. 2009 April 1; 2(2): 88-92]. Other than waiting for the
`patient to adapt, strategies to reduce the pain include: use of
`anesthetics placed on or injected into the skin near the stimu(cid:173)
`lation and placement of foam pads on the skin at the site of
`stimulation [Jeffrey J. BORCKARDT, Arthur R. Smith,
`
`Kelby Hutcheson, Kevin Johnson, Ziad Nahas, Berry Ander(cid:173)
`son, M. Bret Schneider, Scott T. Reeves, and Mark S. George.
`Reducing Pain and Unpleasantness During Repetitive Tran(cid:173)
`scranial Magnetic Stimulation. Journal ofECT 2006; 22:259-
`264], use of nerve blockades [V. HAKKINEN, H. Eskola, A.
`Yli-Hankala, T. Nurmikko and S. Kolehmainen. Which struc(cid:173)
`tures are sensitive to painful transcranial stimulation? Elec(cid:173)
`tromyogr. clin. Neurophysiol. 1995, 35:377-383], the use of
`very short stimulation pulses [V. SUIHKO. Modelling the
`response of scalp sensory receptors to transcranial electrical
`stimulation. Med. Biol. Eng. Comput., 2002, 40, 395-401],
`and providing patients with the amount of information that
`suits their personalities [Anthony DELITTO, Michael J
`Strube, Arthur D Shulman, Scott D Minor. A Study of Dis(cid:173)
`comfort with Electrical Stimulation. Phys. Ther. 1992;
`72:410-424]. U.S. Pat. No. 7,614,996, entitled Reducing dis(cid:173)
`comfort caused by electrical stimulation, to RIEHL discloses
`the application of a secondary stimulus to counteract what
`would otherwise be an uncomfortable primary stimulus.
`However, these methods of reducing pain or discomfort on
`the part of the stimulated patient are not always successful or
`practical.
`
`SUMMARY OF THE INVENTION
`
`[0023] The present invention discloses devices and meth(cid:173)
`ods for the non-invasive treatment of medical conditions,
`utilizing an energy source that transmits energy non-inva(cid:173)
`sively to bodily tissue. In particular, the device can transmit
`energy to, or in close proximity to, one or more selected
`nerves to temporarily stimulate, block and/or modulate elec(cid:173)
`trophysiological signals in the selected nerves.
`[0024]
`In one aspect of the invention, an apparatus for
`applying energy transcutaneously to a target region within a
`patient comprises a source of energy for generating a mag(cid:173)
`netic field that is located essentially entirely exterior to an
`outer skin surface of the patient and a conduction medium
`through which an electrical current induced by the magnetic
`field penetrates the outer skin surface of the patient. The
`source of energy and the conduction medium are configured
`to shape the electrical field that is induced by the magnetic
`field, such that energy from the induced electric field and/or
`induced current is sufficient to modulate a nerve at the target
`region. The source of energy is preferably a source of elec(cid:173)
`trical energy coupled to a coil housed within an enclosure that
`is configured to contain the magnetic field therein.
`[0025]
`In one embodiment, the source of energy comprises
`a source of electrical energy coupled to first and second coils
`configured to generate first and second time-varying mag(cid:173)
`netic fields; each coil being housed within an enclosure con(cid:173)
`figured to substantially confine the magnetic field therein.
`The first and second coils are preferably toroidal such that the
`first coil is configured to orient the first magnetic field in a first
`direction around the first toroid and the second coil is config(cid:173)
`ured to orient the second magnetic field in a second direction
`around the second solenoid, and wherein the first and second
`directions are opposite. The conduction medium is preferably
`positioned in electrical contact to a portion of an outside
`surface of the enclosure to at least partially restrict the direc(cid:173)
`tion of the electric field. In an exemplary embodiment, the
`conduction medium comprises an electrically conductive
`fluid, such as a solution of electrolytes or a conductive gel,
`housed within the outer enclosure and at least
`[0026]
`In another aspect of the invention, a method is pro(cid:173)
`vided for selectively applying energy to a target region within
`
`LUMENIS EX1049
`Page 13
`
`

`

`US 2011/0125203 Al
`
`May 26, 2011
`
`4
`
`a patient. The method includes generating a time-varying
`magnetic field that is located essentially entirely outside of
`the patient and shaping an electric field induced by the mag(cid:173)
`netic field. An electric current from the electric field is con(cid:173)
`ducted through an outer skin surface of the patient to the target
`region to modulate a nerve at the target region. The target
`region is preferably at least approximately 1-2 cm below the
`outer skin surface and preferably about 2-5 cm below the
`outer skin surface. The electric field is constrained from
`modulating one or more nerves in a second region between
`the outer skin surface and the target region.
`In one embodiment, the generating step comprises
`[0027]
`generating the time-varying magnetic field within a first
`enclosed coil and generating a second time-varying magnetic
`field within a second enclosed coil positioned near or adjacent
`to the first enclosed coil. In an alternative embodiment, the
`shaping step comprises positioning a conducting medium
`around a portion of the enclosed coil such that the direction of
`the electrical field is constrained within the conducting
`medium. In yet another embodiment, the shaping step com(cid:173)
`prises positioning an electrical insulator around a portion of
`the enclosed coil such that the component of the induced
`electric field normal to the surface of the insulator is zero.
`In another aspect of the present invention, a device
`[0028]
`comprises a source of electrical power, a magnetically per(cid:173)
`meable toroidal core, and a coil that is wound around the core.
`The device also comprises a continuous electrically conduct(cid:173)
`ing medium in which the coil and core are embedded, wherein
`the conducting medium has a shape that conforms to the
`contour of an arbitrarily oriented target body surface of a
`patient when the medium is applied to the target body surface.
`The source of power supplies a pulse of electric charge to the
`coil, such that the coil induces an electric current and/or an
`electric field within the patient, thereby stimulating tissue
`and/or one or more nerve fibers within the patient.
`[0029] Because coils of the device produce time-varying
`magnetic fields when time-varying currents are passed
`through the coils, and because the time-varying magnetic
`fields induce an electric current and/or an electric field within
`the patient, the device is known as a magnetic stimulator.
`Because the magnetically permeable cores of the device and
`their corresponding coils are in the shape of a toroid, the
`device is known as a toroidal magnetic stimulator. In one
`aspect of the invention, a toroidal core comprises a high(cid:173)
`permeability material such as Supermendur, wherein current
`passing through the coil produces a magnetic field within the
`core of about 0.1 to 2 Tesla. Current passing through a coil
`may be about 0.5 to 20 amperes, typically 2 amperes, with
`voltages across each coil of 10 to 100 volts. The current is
`passed through the coils in bursts of pulses. The burst repeats
`at 1 Hz to 5000 Hz, preferably at 15-50 Hz. The pulses have
`duration of 20 to 1000 microseconds, preferably 200 micro(cid:173)
`seconds and there may be 1 to 20 pulses per burst.
`[0030] The disclosed invention shapes an elongated electric
`field of effect that can be oriented parallel to a long nerve. In
`a preferred embodiment, the device comprises two toroidal
`cores that lie side-by-side one another, around which coils are
`wound. In one embodiment, coils are wound with the same
`handedness around the cores, and current is passed in oppo(cid:173)
`site directions through the coils. In another embodiment, coils
`are wound with the opposite handedness around the cores,
`and current is passed in the same direction through the coils.
`In other embodiments of the invention, the device comprises
`
`more than two toroids, and the shapes of the toroids may be
`configured to have non-planar or non-circular geometries.
`In one embodiment of the present invention, the
`[0031]
`electrically conducting medium is contained within a cham(cid:173)
`ber having apertures on its surface that are adapted to dis(cid:173)
`pense the conducting medium through the apertures to the
`target surface of the patient. In another embodiment, interface
`material is interposed between the conducting medium and
`the target surface of a patient, such that the conducting
`medium leaks through the interface to make electrical contact
`with the skin of the patient. For example the interface material
`may be electrically conducting material that is hydrophilic, an
`electrically conducting hydrogel, or a material such as Mylar
`having a sub-micron thickness and a high dielectric constant,
`for example, a dielectric constant of about 3. In another
`embodiment of the invention, the conducting medium is con(cid:173)
`tained within a conducting deformable elastomeric balloon.
`In one embodiment of the present invention, the
`[0032]
`magnetic stimulator preferably operates to induce an electri(cid:173)
`cal signal within the tissue, where the induced electrical sig(cid:173)
`nal has a frequency between about 1 Hz to 3000 Hz and a
`pulse duration of between about 10-1000 microseconds. By
`way of example, at least one induced electrical signal may be
`of a frequency between about 15 Hz to 35 Hz. By way of
`example, at least one induced electrical signal may have a
`pulsed on-time of between about 50 to 1000 microseconds,
`such as between about 100 to 300 microseconds. The induced
`electrical signal may have any desired waveform, which may
`be one or more of: a full or partial sinusoid, a square wave, a
`rectangular wave, and triangle wave.
`In one aspect of the invention, the disclosed device
`[0033]
`is configured to induce a peak pulse voltage sufficient to
`produce an electric field in the vicinity of a nerve to cause the
`nerve to depolarize and reach a threshold for action potential
`propagation. By way of example, the threshold electric field
`for stimulation of nerve terminals may be about 8 V /mat 1000
`Hz. For example, the device may induce an e