WO2009029977A1 - Transcutaneous energy transfer coil assembly - Google Patents

Transcutaneous energy transfer coil assembly Download PDF

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Publication number
WO2009029977A1
WO2009029977A1 PCT/AU2008/001302 AU2008001302W WO2009029977A1 WO 2009029977 A1 WO2009029977 A1 WO 2009029977A1 AU 2008001302 W AU2008001302 W AU 2008001302W WO 2009029977 A1 WO2009029977 A1 WO 2009029977A1
Authority
WO
WIPO (PCT)
Prior art keywords
assembly
coil
connector
patient
tet
Prior art date
Application number
PCT/AU2008/001302
Other languages
French (fr)
Inventor
Francesca Paris
Peter Joseph Ayre
Original Assignee
Ventrassist Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2007904754A external-priority patent/AU2007904754A0/en
Application filed by Ventrassist Pty Ltd filed Critical Ventrassist Pty Ltd
Publication of WO2009029977A1 publication Critical patent/WO2009029977A1/en

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Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00Electrotherapy; Circuits therefor
    • A61N1/18Applying electric currents by contact electrodes
    • A61N1/32Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/372Arrangements in connection with the implantation of stimulators
    • A61N1/37211Means for communicating with stimulators
    • A61N1/37217Means for communicating with stimulators characterised by the communication link, e.g. acoustic or tactile
    • A61N1/37223Circuits for electromagnetic coupling
    • A61N1/37229Shape or location of the implanted or external antenna
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00Electrotherapy; Circuits therefor
    • A61N1/18Applying electric currents by contact electrodes
    • A61N1/32Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/372Arrangements in connection with the implantation of stimulators
    • A61N1/378Electrical supply
    • A61N1/3787Electrical supply from an external energy source

Definitions

  • the present invention relates to energy transfer coil assemblies and in particular to Transcutaneous Energy Transfer (TET) coil assemblies and systems for providing energy and/or data to/from implantable medical devices.
  • TET Transcutaneous Energy Transfer
  • Transcutaneous Energy Transfer Systems can be used to power implantable medical devices (IMDs) such as blood pumps, and neural stimulators without the need for a permanent percutaneous lead to cross the skin layer of the patient.
  • TETS usually function by mounting an electromagnetic coil of wire on respective sides of the skin layer and transmitting electrical signals therebetween across the skin layer.
  • An advantage of TETS relative to using percutaneous leads is the reduction or elimination of infection that can be associated with percutaneous leads at the exit site of the lead through the patient's skin layer.
  • Another advantage may include that the patient feels they have less of a burden with a TETS compared to using a percutaneous lead, in that they can have periods of untethered support where the IMD is powered and controlled by an implantable rechargeable battery and controller.
  • TETS are not without their own problems.
  • One difficulty with TETS is that for maximum efficiency of energy transfer between the coils, both the coils need to be in axial alignment. Therefore, there is a need for a convenient, relatively painless method or system for attaching and/or positioning an external transcutaneous energy and/or transfer (TET) coil on the patient in relation to an implanted TET coil.
  • TET transcutaneous energy and/or transfer
  • positioning magnets are used to centre and align the two coils.
  • the positioning magnets may cause discomfort to the patient and patients may develop pressure sores in the localised regions of their skin near the magnets because of the clamping force applied across the skin layer between the attracted magnets.
  • the patient may also experience adverse heating events due to the proximity of the positioning magnets to the electromagnetic fields generated by the coils; this is particularly an issue if the magnets are undesirably heated such that they cause localised damage to the patient.
  • a transcutaneous energy transfer (TET) coil assembly comprising: a support having an induction coil mounted thereon; and a first connector on or in the support for releasable non-magnetic physical connection to a second connector mountable to an external skin surface of a patient, wherein the TET coil assembly is configured for transcutaneous inductive coupling to a second TET coil assembly.
  • TET transcutaneous energy transfer
  • a releasable non-magnetic physical connection can reduce the risk of pressure sores on the patient compared with prior art transcutaneous magnetic connectors.
  • the connectors may comprise respective male and female couplable portions.
  • the first connector may comprise the female couplable portion.
  • the male and female couplable portions may be configured for releasable snap-locking engagement. Such an arrangement may provide a connection type which is simple and convenient for patient use.
  • the first connector is at least approximately central of the induction coil.
  • the coil may be annular or torroidal.
  • the induction coil may be encapsulated by the support and the first connector may be formed on or in the support.
  • the first connector may be a recess or hole formed in the support.
  • the assembly may comprise the second connector.
  • the second connector may comprise an adhesive surface for adhesion to the external skin surface of the patient.
  • the assembly may comprise two or more first connectors. This may provide more stability in connection of the TET coil assembly to the patient.
  • the two or more first connectors may be spaced from a central region of the coil.
  • the central region may comprise the portion of the assembly in the middle of the annular coil, within the centre defined by the annular coil.
  • the assembly comprises at least one other connector on the support other than the first connector, the at least one other connector comprising a magnetic device for magnetic connection to a magnetic device on or in the patient.
  • the magnetic device on or in the patient is on the patient, the magnetic device may be associated with the second connector.
  • the assembly may be configured for electrical connection to a controller and/or power supply for controlling/powering an implantable medical device via the second TET coil assembly.
  • a transcutaneous energy transfer
  • TET transcutaneous inductive coupling with an internally located TET coil assembly.
  • the connectors may comprise respective male and female couplable portions.
  • the first connector may comprise the female couplable portion.
  • the male and female couplable portions may be configured for releasable snap-locking engagement.
  • the first connector is configured for releasable non-magnetic physical connection to the second connector.
  • the first connector is at least approximately central of the induction coil.
  • the coil may be annular or torroidal.
  • the induction coil may be encapsulated by the support and the first connector may be formed on or in the support.
  • the first connector may be a recess or hole formed in the support.
  • the assembly may comprise the second connector.
  • the second connector may comprise an adhesive surface for adhesion to the external skin surface of the patient.
  • the assembly may comprise two or more first connectors. This may provide more stability in connection of the TET coil assembly to the patient.
  • the two or more first connectors may be spaced from a central region of the coil.
  • the central region may comprise the portion of the assembly in the middle of the annular coil, within the centre defined by the annular coil.
  • the assembly comprises at least one other connector on the support other than the first connector, the at least one other connector comprising a magnetic device for magnetic connection to a magnetic device on or in the patient.
  • the magnetic device on or in the patient is on the patient, the magnetic device may be associated with the second connector.
  • the assembly may be configured for electrical connection to a controller and/or power supply for controlling/powering an implantable medical device via the second TET coil assembly.
  • a transcutaneous energy transfer
  • TET TET
  • system comprising: a first TET coil assembly implantable in a patient beneath a portion of a skin layer of a patient and connectable to an implantable medical device; and a second TET coil comprising the TET coil assembly of any one of the above described aspects and/or their optional features.
  • an energy transfer coil assembly comprising: a support having an energy transfer coil mounted thereon; and a first connector on or in the support for releasable non-magnetic physical connection to a second connector mountable to an external skin surface of a patient, wherein the coil assembly is configured for electrical energy transfer coupling to a second energy transfer coil assembly.
  • the connectors may comprise respective male and female couplable portions.
  • the first connector may comprise the female couplable portion.
  • the male and female couplable portions may be configured for releasable snap-locking engagement. Such an arrangement may provide a connection type which is simple and convenient for patient use.
  • the energy transfer coil assembly comprises a transcutaneous energy transfer (TET) coil assembly.
  • TET transcutaneous energy transfer
  • the TET coil assembly may comprise any one or more of the above described optional features with respect to eh above described aspects.
  • an energy transfer coil assembly comprising: a support having an energy transfer coil mounted thereon; a first connector on the support; and a second connector mountable to an external skin surface of a patient, wherein the first and second connectors are configured for releasable physical connection to each other, and the energy transfer coil assembly is configured for electrical coupling with an internally located transcutaneous energy transfer (TET) coil assembly.
  • the connectors may comprise respective male and female couplable portions.
  • the first connector may comprise the female couplable portion.
  • the male and female couplable portions may be configured for releasable snap-locking engagement.
  • Such an arrangement may provide a connection type which is simple and convenient for patient use.
  • the energy transfer coil assembly comprises a transcutaneous energy transfer (TET) coil assembly.
  • the TET coil assembly may comprise any one or more of the above described optional features with respect to eh above described aspects.
  • a TETS external coil assembly for use with a TETS internal coil assembly implanted within a patient, operably connected to an implanted medical device, wherein said TETS external coil assembly comprises a first mating member and a second mating member, said first mating member is removably attachable to the skin layer of said patient by a means of adhesion, and said second mating member comprising an encapsulated coil, said first mating member and said second mating member each having a coupling member, the respective coupling members capable of being selectively and removably coupled to each other.
  • At least one of said coupling members is electrically non- conductive.
  • said coupling members are snap connectors.
  • said coupling member on said second mating member is disposed at the centre of said coil.
  • said coupling member on said first mating member is disposed at or near the centre thereof.
  • said first mating member is a substantially flat disc shape.
  • said assembly includes at least a partial coating of anti-infective or antimicrobial material.
  • said means of adhesion is an adhesive layer disposed on said first mating member.
  • said adhesive layer is comprised of a relatively long lasting adhesive and is not water soluble.
  • a TETS external coil assembly for use with a TETS internal coil assembly implanted within a patient, operably connected to an implanted medical device, wherein said TETS external coil assembly comprises first and second mating members capable of being selectively and removably coupled to each other, said first mating member removably attachable to a skin layer via an adhesive, and said second mating member comprises an encapsulated coil.
  • said first mating member has a first coupling member able to be removably attached to a second coupling member disposed on said second mating member, at least one of said first and second coupling members being electrically non- conductive.
  • a method for attaching a TETS external coil assembly to a skin layer comprises a first step of adhering a first mating member to said skin layer by a means of adhesion, said first mating member comprising a first coupling member; and a second step of attaching a second mating member to said first mating member via a second coupling member disposed on said second mating member, said second coupling member capable of being selectively and removably coupled with said first coupling member, and said second mating member including an encapsulated coil.
  • Figure 1 is a schematic view of a TETS that may incorporate any of the embodiments of the present invention
  • Figure 2 is a transparent plan view of an external TET coil assembly in accordance with an embodiment of the present invention
  • Figure 3 is a cross-sectional view of the coil assembly illustrated in Figure 2 taken on line 3-3;
  • Figure 4 is a plan view of a second connector for use with an embodiment of the present invention.
  • Figure 5 is a cross-sectional view of the second connector illustrated in Figure 4 taken on line 5-5;
  • Figure 6 is a plan view of another embodiment of a second connector
  • Figure 7 is a transparent plan view of another embodiment of an external TET coil assembly
  • Figure 8 is a cross-sectional view of the coil assembly illustrated in Figure 7 taken on line 8-8;
  • Figure 9 is a front elevation of a patient showing an implanted part of a TETS in dotted outline; Figures 10 and 11 illustrate the patient of Figure 9 further illustrating various components of at least one embodiment of the present invention;
  • Figures 12 and 13 are cross-sectional side elevations of the coil assembly illustrated in Figure 3 and the second connector illustrated in Figure 5 de-coupled and coupled, respectively;
  • Figure 14 is a transparent plan view of an external TET coil assembly in accordance with another embodiment of the present invention.
  • Figure 15 is a plan view of an alternative embodiment of a second connector
  • Figure 16 is a transparent plan view of another embodiment of an internal TET coil assembly
  • Figure 17 is a transparent plan view of another embodiment of an external TET coil assembly
  • Figure 18 is a plan view of a coil for use with an external or internal TET coil assembly.
  • a Transcutaneous Energy and/or Data Transfer System which comprises an internal, or implantable, transcutaneous energy and/or data transfer (TET) coil assembly 50 and an external TET coil assembly 51 which electrically interconnect components internally disposable within a patient with externally disposable components, where in use the implanted and external TET coil assemblies 50, 51 are separated by a skin layer SL of the patient.
  • TET transcutaneous energy and/or data transfer
  • the internal, or implantable, components comprise a blood pump 52, for example a left ventricular assist device (LVAD), connected by a lead Ll to an internal controller 53.
  • the internal controller 53 includes a small battery, preferably a lithium ion rechargeable battery 54, encapsulated within a biocompatible housing 55, such as an injection moulded silicone housing, or a titanium housing.
  • the internal controller 53 is electrically connected by a lead L2 to the internal TET coil assembly 50 which is mounted in parallel to and just beneath the skin layer SL of the patient.
  • the blood pump 52 may be any type of blood pump. For example, it may be of a type implanted directly below the patient's heart, such as the VentrAssist®
  • LVAD by Ventracor Limited, Sydney Australia, or it may be implanted in the thoracic region of the patient, such as the pump disclosed in US-B-6530876.
  • the internal TET coil assembly 50 may be implanted, for example, in the abdominal region of the patient, also as disclosed in US-B-6530876.
  • the type and location of blood pump and internal TET coil assembly are not limited to these examples.
  • the internal TET coil assembly 50 is electrically inductively couplable to the external TET coil assembly 51 which in use is configured to occur across the patient's skin layer SL.
  • the external TET coil assembly 51 is mounted at least approximately in parallel to the internal coil assembly 50 on the opposite, external side of the skin layer SL. It is preferred that the distance between the internal and external coil assemblies 50,51 is kept to a minimum to increase efficiency of energy and/or data transfer between the internal and external coil assemblies 50,51.
  • the internal TET coil assembly 50 would therefore preferably be mounted immediately below the skin layer SL, and the external TET coil assembly 51 would preferably be mounted or positioned on or as close to the skin layer SL as possible.
  • the external TET coil assembly 51 is connectable by a lead 56 to an external controller 57, which includes a rechargeable battery, such as a lithium ion battery, to act as a power supply.
  • the external controller 57 is also selectively connectable to an alternative power supply, such as mains power which is used either to supply power to the controller or to recharge the battery in the external controller 57.
  • the external controller 57 is also connectable to a PC running a Graphical User Interface (GUI) 58, which may be used: to update the software components; download results and data; and/or adjust the operating parameters of the blood pump 52 or the overall system.
  • GUI Graphical User Interface
  • Internal TET coil assembly 50 and external TET coil assembly 51 cooperate, when in use, to transmit electrical signals across the electrical gap made by the skin layer SL.
  • the electrical signals transferred are one or both of energy/power supply or data.
  • the TETS is configured to allow power supply to be directed from the external coil assembly 51 to the internal coil assembly 50, while data transmission can occur in both directions.
  • the external coil 51 is energised with an electrical current or signal, a reciprocal current or signal is generated in the implanted coil 50, thus allowing for the transmission of electrical power and signals.
  • FIG. 2 and 3 illustrate a TET coil assembly in the form of an external TET coil assembly 51.
  • the external TET coil assembly 51 includes an induction coil in the form of a coil 59 of electrically conductive wire encapsulated within a layer of corrosion resistant material that prevents or limits the ingress of fluid or oxidising agent to adversely affect the wire.
  • this first layer of material is poly-fluoro-acetate (PFA).
  • PFA poly-fluoro-acetate
  • the combination of PFA and copper wire is then injection moulded within a support in the form of a housing 60 of a biocompatible material, preferably flexible, such as silicon.
  • the coil 59 forms a generally planar, pancake, annular/torroidal shape having an external diameter of about 50mm, but which may be in the range of 30mm to 70mm, or more preferably 40mm to 60mm.
  • the coil 59 of this embodiment has a central aperture or void region 61 having a diameter of about 20mm, but which may be in the range of 3mm to 40 mm, or more preferably 10mm to 30mm.
  • the void region 61 generally increases the overall efficiency of transmission of the TETS. It may also reduce the heat generated by external coil 59.
  • the coil 59 is formed from spiral windings of Litz wire due to its relatively low resistance and high conductivity. Depending on the gauge of the Litz wire, which for example may be about 16AWG to 22 AWG, the coil 59 may comprise about six to thirteen turns or windings.
  • the coil 59 is integrally joined to lead 56 which encapsulates the beginning and end wires, 62a,b, joining the coil 59 at its beginning and end windings.
  • the external TET coil assembly 51 is preferably connected to other electrical components by the use of the beginning and end wires 62a,b, which may also preferably be coated with PFA and then encapsulated within a silicone moulded sheath to form the lead 56.
  • the lead 56 is, in this embodiment, silicon, however may be in any appropriate material. Whereas the beginning and end wires 62a ,b are illustrated in Figure 2 in two spaced and side-by- side parts, they may be braided or twisted together. Alternatively, the spiral windings may be formed from thin braided copper wire fashioned into a continuous coil.
  • the external TET coil assembly 51 comprises a first connector having a female couplable portion in the form of a female press stud connector or hole 63.
  • the hole 63 is centrally located with respect to the annular coil 59.
  • the external TET coil assembly 51 also comprises a second connector in the form of an adhesive patch 66 comprising a male couplable portion in the form of a male press stud connector or post 64 being part of the adhesive patch 66, as illustrated in Figures 4 and 5.
  • the hole 63 is configured for releasable non-magnetic physical connection to the post 64.
  • the physical connection is provided as a releasable snap-locking engagement with the post 64 of the adhesive patch 66.
  • the post 64 of this embodiment comprises a head 68 and neck 70.
  • the post 64 is configured such that the diameter of the head 68 of the post 64 is greater than the diameter of the hole 63.
  • the head 68 of the post 64 must be forced through the hole 63, such that when engaged, the bore 72 of the hole 63 rests about the neck 70.
  • the adhesive patch of this embodiment is an electrocardiogram (ECG) electrode, such as the "RED DOT®” electrode of 3M Company, Minnesota, USA, or of the type described in US-B-7,245,957.
  • ECG electrocardiogram
  • US-B-7,245,957 describes a medical snap- lock connector system, whereby an adhesive strip is adhered to the skin layer of a patient.
  • the snap connector described in US-B-7,245,957 is adapted to be electrically conductive on the patient' s skin such that ECG equipment connected by leads to the adhesive strip can passively detect electrical signals generated by the patient's heart.
  • the ability of these ECG electrodes to be electrically conductive on the patient's skin SL is not required for the present embodiment of the internal TET coil 50 to function.
  • the adhesive patch 66 comprises an adhesive layer 74 having an adhesive surface 76 with an adhesive substance thereon.
  • the adhesive substance is biocompatible to prevent or limit patient discomfort and also may be impermeable to water or at least resistant to water so that the adhesive layer 74 is not accidentally removed from the skin layer SL during normal washing.
  • the adhesive layer is breathable.
  • the adhesive layer is mounted to a second layer 78 adapted to reinforce the overall structure of the adhesive patch 66, where the second layer 78 is less flexible than the adhesive layer 74.
  • the post 64 is itself mounted to the second layer 78.
  • the adhesive layer 74 of the present embodiment is provided on the adhesive patch 66, it should be understood that in alternative embodiments the adhesive patch 66 may not be provided with an adhesive layer and the user will attach the adhesive patch by another "means of adhesion" such as a bio-compatible double- sided tape or by applying a bio-compatible compatible glue.
  • the adhesive patch of the above embodiment typically comprises an electrically conductive paste on the adhesive surface 76 and also the post 64 is itself electrically conductive.
  • the non-electrically conductive post 64 may comprise a material such as ceramic or suitable polymer.
  • a central metal post 64 may act as a conductor during inductive energy transfer between the external TET coil assembly 51 and internal TET coil assembly 50 and heat up causing discomfort or, in some circumstances, damage to the patient's skin layer in the immediate vicinity of the adhesive patch 66. Electrically conductive connectors such as the post 64 may work with the present embodiment, but not as efficiently.
  • the patch 66 merely comprises a single layer 80 to which the post 64 is attached.
  • the single layer 80 and post 64 are integrally formed, such that the single layer forms a flange from the post, the flange having an adhesive on its surface (not shown) opposite to the surface 82 with the post 64 for adhering to the patient.
  • the single layer may be configured to be breathable to increase patient comfort.
  • the hole 63 is formed in the silicon housing 60 either by being cut in the housing 60 or moulded therein.
  • the hole is formed in the centre of a plastic insert 84 which is itself mounted within an aperture 85 in the silicon housing 60.
  • the plastic insert 84 is relatively less flexible than the silicon housing 60 and can provide a relatively stronger coupling fit with the post 64 compared with the hole of the previously described embodiments.
  • the coil 59 is mounted on a backing plate 86.
  • the backing plate 86 is preferably ferrite and fitted to the back of the external coil 59, to increase transfer efficiency of the EMF generated by the coil 59 when energised.
  • the coil 59 and backing plate 86 being encapsulated in PFA which is in turn encapsulated in silicon to form the housing 60.
  • the coil 59 and backing plate 86 are encapsulated in silicon only. While this embodiment has been described by combining the plastic insert 84 feature and the backing plate 86 feature, it will be understood that each feature may exist in alternative embodiments separate from each other.
  • FIG 9 illustrates a patient P with a blood pump 52 implanted such that it draws blood from the patient's heart H via inflow cannula 88 and returns it to the patient's aorta A via outflow cannula 90.
  • the blood pump 52 is controlled by internal controller 53 which in this embodiment houses the battery.
  • An internal TET coil assembly 50 is directly electrically connected to the internal controller 53 by lead L2 and is located in the patient's right sub-clavicle thoracic region. As will be understood, the internal TET coil assembly 50 in alternative embodiments may be positioned elsewhere, such as in the patient's abdominal area.
  • Figure 10 illustrates the patient P with an adhesive patch 66 affixed to the skin layer of his chest directly over the site of the internal TET coil assembly 50.
  • the patient P is able to feel the outline of the internal TET coil assembly 50 under his skin layer to be able to locate the adhesive patch 66 directly thereover or as close as possible thereto.
  • Figure 11 illustrates the patient P with the external TET coil assembly 51 having been snap-lockingly coupled to the adhesive patch 66.
  • the external TET coil assembly 51 is connected to external controller 57, which includes a battery therein, by lead 56.
  • the external controller 57 may be carried by the patient in a suitable bag or sling.
  • This overall configuration allows external TET coil assembly 51 to be positioned and aligned correctly with the internal TET coil assembly 50 without the need for positioning magnets that are commonly used in the prior art.
  • the external TET coil assembly is securely positioned relative to skin layer by the adhesive patch 66.
  • the external controller and battery 57 can then power and control the blood pump 52 via an inductive transcutaneous energy transfer between the external and internal TET coil assemblies 51, 50.
  • Figures 12 and 13 illustrate the snap-locking engagement or coupling between hole 63 and post 64 in more detail.
  • adhesive patch 66 is affixed to the patient's skin layer SL with post 64 directed away from the skin layer SL.
  • the hole 63 of the external TET coil assembly 51 is presented to the post 64.
  • the head 68 of the post 64 has been forced through the hole 63 to provide the snap-locking engagement.
  • the external TET coil assembly 51 can be released or decoupled from the adhesive patch by forcing the head 68 of the post 64 back through the hole 63.
  • the snap-locking connection may be arranged in other forms.
  • the hole 63 may take the form of a recess which does not pass entirely through the housing 60, but only partway through.
  • the post 64 when coupled to the hole (recess) would be releasably retained in the housing 60.
  • the recess may be shaped in a complementary fashion with respect to the post 64.
  • FIGS 14 and 15 illustrate an alternative embodiment of the external TET coil assembly 51 where like reference numerals denote like parts.
  • the external TET coil assembly 51 comprises four circumferentially located holes 63' configured for snap-locking engagement with four complementarily spaced posts 64' on a corresponding adhesive patch 66'.
  • the external TET coil assembly 51 can then be coupled to the patch 66' in four different radial positions on the patch 66 while maintaining the same relative axial position.
  • Alternative arrangements of this embodiment may comprise more or fewer holes and posts 63, 64. For example, there may be two or more holes and posts 63, 64.
  • the connectors of the abovementioned embodiments may be used in conjunction with a magnet arrangement.
  • the use of stud connectors or other coupling members means the magnets used may require less attractive force, than is employed in the prior art, or would be required by use of magnets alone, and therefore be less uncomfortable and detrimental to the patient, than the prior art magnets.
  • Such magnets may preferably be disposed at or near the periphery of at least one of the mating members.
  • FIG. 16 illustrates an external TET coil assembly 51
  • Figure 17 illustrates an internal TET coil assembly 50
  • the internal TET coil assembly 50 comprises four magnets 92 circumferentially spaced about the internal coil 94.
  • this embodiment of the internal TET coil assembly 50 is implanted in a patient in the same manner described above in relation to the previously described embodiments.
  • the external TET coil assembly 51 illustrated in Figure 16 comprises a hole 63 for engagement with a patch 66 such as those described above.
  • the external TET coil assembly 51 further comprises positioning magnets 100 for mutual magnetic connection with corresponding magnets 92 on the internal TET coil assembly 50.
  • the internal and external TET coils 50, 51 illustrated in Figure 16 and 17 comprise four and three magnets 92, 100 respectively, they may contain more or fewer magnets to provide different potential radial magnetic coupling orientations of the external TET coil assembly 51 with respect to the internal TET coil assembly 50 while maintaining the same relative axial position.
  • the internal coil 94 is illustrated as an annular disc in Figure 17, it is formed in practice by a flat spiral wound coil starting from lead wire 95 and ending with lead wire 96 and which defines a void 97 in the middle of the flat spiralled coil 94.
  • An example of such a coil is illustrated in Figure 18, where like reference numerals denote like parts, which may form the coil of either the internal or external TET coil assembly 50,51.

Abstract

A transcutaneous energy transfer (TET) coil assembly comprises a support having an induction coil mounted thereon and a first connector on the support. The first connector is arranged for releasable non-magnetic physical connection to a second connector mountable to an external skin surface of a patient. The TET coil assembly is configured for transcutaneous inductive coupling to a second TET coil assembly. The first and second connectors may be corresponding male and female connectors, and may be arranged for releasable snap-lock connection.

Description

TRANSCUTANEOUS ENERGY TRANSFER COIL ASSEMBLY
TECHNICAL FIELD
The present invention relates to energy transfer coil assemblies and in particular to Transcutaneous Energy Transfer (TET) coil assemblies and systems for providing energy and/or data to/from implantable medical devices.
BACKGROUND ART
Transcutaneous Energy Transfer Systems (TETS') can be used to power implantable medical devices (IMDs) such as blood pumps, and neural stimulators without the need for a permanent percutaneous lead to cross the skin layer of the patient. TETS usually function by mounting an electromagnetic coil of wire on respective sides of the skin layer and transmitting electrical signals therebetween across the skin layer. An advantage of TETS relative to using percutaneous leads is the reduction or elimination of infection that can be associated with percutaneous leads at the exit site of the lead through the patient's skin layer. Another advantage may include that the patient feels they have less of a burden with a TETS compared to using a percutaneous lead, in that they can have periods of untethered support where the IMD is powered and controlled by an implantable rechargeable battery and controller.
However, TETS are not without their own problems. One difficulty with TETS is that for maximum efficiency of energy transfer between the coils, both the coils need to be in axial alignment. Therefore, there is a need for a convenient, relatively painless method or system for attaching and/or positioning an external transcutaneous energy and/or transfer (TET) coil on the patient in relation to an implanted TET coil.
In some prior art systems, positioning magnets are used to centre and align the two coils. However, the positioning magnets may cause discomfort to the patient and patients may develop pressure sores in the localised regions of their skin near the magnets because of the clamping force applied across the skin layer between the attracted magnets. Furthermore, the patient may also experience adverse heating events due to the proximity of the positioning magnets to the electromagnetic fields generated by the coils; this is particularly an issue if the magnets are undesirably heated such that they cause localised damage to the patient.
Another prior art system, described in US-A-2005/0288743, includes the use of a vest or shoulder sling to be worn by the patient, where the vest includes pockets for holding the external TET coil.
It is an object of at least one of the preferred embodiments to overcome or ameliorate at least one of the problems of the prior art, or at least to provide a useful alternative thereto.
SUMMARY OF THE INVENTION
According to a first aspect of the invention there is provided a transcutaneous energy transfer (TET) coil assembly comprising: a support having an induction coil mounted thereon; and a first connector on or in the support for releasable non-magnetic physical connection to a second connector mountable to an external skin surface of a patient, wherein the TET coil assembly is configured for transcutaneous inductive coupling to a second TET coil assembly.
A releasable non-magnetic physical connection can reduce the risk of pressure sores on the patient compared with prior art transcutaneous magnetic connectors.
Optionally, the connectors may comprise respective male and female couplable portions. The first connector may comprise the female couplable portion. The male and female couplable portions may be configured for releasable snap-locking engagement. Such an arrangement may provide a connection type which is simple and convenient for patient use.
Optionally, at least a portion of the first connector is at least approximately central of the induction coil. The coil may be annular or torroidal. The induction coil may be encapsulated by the support and the first connector may be formed on or in the support. For example, the first connector may be a recess or hole formed in the support.
Optionally, the assembly may comprise the second connector.
Optionally, the second connector may comprise an adhesive surface for adhesion to the external skin surface of the patient.
Optionally, the assembly may comprise two or more first connectors. This may provide more stability in connection of the TET coil assembly to the patient. The two or more first connectors may be spaced from a central region of the coil. For example, if the coil is annular, the central region may comprise the portion of the assembly in the middle of the annular coil, within the centre defined by the annular coil.
Optionally, the assembly comprises at least one other connector on the support other than the first connector, the at least one other connector comprising a magnetic device for magnetic connection to a magnetic device on or in the patient. Where the magnetic device on or in the patient is on the patient, the magnetic device may be associated with the second connector.
Optionally, the assembly may be configured for electrical connection to a controller and/or power supply for controlling/powering an implantable medical device via the second TET coil assembly. According to another aspect there is provided a transcutaneous energy transfer
(TET) coil assembly comprising: a support having an induction coil mounted thereon; a first connector on or in the support; and a second connector mountable to an external skin surface of a patient, wherein the first and second connectors are configured for releasable physical connection to each other, and the TET coil assembly is configured for transcutaneous inductive coupling with an internally located TET coil assembly.
Optionally, the connectors may comprise respective male and female couplable portions. The first connector may comprise the female couplable portion. The male and female couplable portions may be configured for releasable snap-locking engagement. - A -
Optionally, the first connector is configured for releasable non-magnetic physical connection to the second connector.
Optionally, at least a portion of the first connector is at least approximately central of the induction coil. The coil may be annular or torroidal. The induction coil may be encapsulated by the support and the first connector may be formed on or in the support. For example, the first connector may be a recess or hole formed in the support.
Optionally, the assembly may comprise the second connector.
Optionally, the second connector may comprise an adhesive surface for adhesion to the external skin surface of the patient.
Optionally, the assembly may comprise two or more first connectors. This may provide more stability in connection of the TET coil assembly to the patient. The two or more first connectors may be spaced from a central region of the coil. For example, if the coil is annular, the central region may comprise the portion of the assembly in the middle of the annular coil, within the centre defined by the annular coil.
Optionally, the assembly comprises at least one other connector on the support other than the first connector, the at least one other connector comprising a magnetic device for magnetic connection to a magnetic device on or in the patient. Where the magnetic device on or in the patient is on the patient, the magnetic device may be associated with the second connector.
Optionally, the assembly may be configured for electrical connection to a controller and/or power supply for controlling/powering an implantable medical device via the second TET coil assembly. According to another aspect there is provided a transcutaneous energy transfer
(TET) system comprising: a first TET coil assembly implantable in a patient beneath a portion of a skin layer of a patient and connectable to an implantable medical device; and a second TET coil comprising the TET coil assembly of any one of the above described aspects and/or their optional features.
According to another aspect there is provided an energy transfer coil assembly comprising: a support having an energy transfer coil mounted thereon; and a first connector on or in the support for releasable non-magnetic physical connection to a second connector mountable to an external skin surface of a patient, wherein the coil assembly is configured for electrical energy transfer coupling to a second energy transfer coil assembly.
Optionally, the connectors may comprise respective male and female couplable portions. The first connector may comprise the female couplable portion. The male and female couplable portions may be configured for releasable snap-locking engagement. Such an arrangement may provide a connection type which is simple and convenient for patient use.
Optionally, the energy transfer coil assembly comprises a transcutaneous energy transfer (TET) coil assembly. The TET coil assembly may comprise any one or more of the above described optional features with respect to eh above described aspects.
According to another aspect there is provided an energy transfer coil assembly comprising: a support having an energy transfer coil mounted thereon; a first connector on the support; and a second connector mountable to an external skin surface of a patient, wherein the first and second connectors are configured for releasable physical connection to each other, and the energy transfer coil assembly is configured for electrical coupling with an internally located transcutaneous energy transfer (TET) coil assembly. Optionally, the connectors may comprise respective male and female couplable portions. The first connector may comprise the female couplable portion. The male and female couplable portions may be configured for releasable snap-locking engagement. Such an arrangement may provide a connection type which is simple and convenient for patient use. Optionally, the energy transfer coil assembly comprises a transcutaneous energy transfer (TET) coil assembly. The TET coil assembly may comprise any one or more of the above described optional features with respect to eh above described aspects.
According to another aspect there is provided a TETS external coil assembly for use with a TETS internal coil assembly implanted within a patient, operably connected to an implanted medical device, wherein said TETS external coil assembly comprises a first mating member and a second mating member, said first mating member is removably attachable to the skin layer of said patient by a means of adhesion, and said second mating member comprising an encapsulated coil, said first mating member and said second mating member each having a coupling member, the respective coupling members capable of being selectively and removably coupled to each other.
Preferably at least one of said coupling members is electrically non- conductive. Preferably said coupling members are snap connectors.
Preferably said coupling member on said second mating member is disposed at the centre of said coil.
Preferably said coupling member on said first mating member is disposed at or near the centre thereof.
Preferably said first mating member is a substantially flat disc shape.
Preferably said assembly includes at least a partial coating of anti-infective or antimicrobial material.
Preferably said means of adhesion is an adhesive layer disposed on said first mating member.
Preferably said adhesive layer is comprised of a relatively long lasting adhesive and is not water soluble. According to another aspect there is provided a TETS external coil assembly for use with a TETS internal coil assembly implanted within a patient, operably connected to an implanted medical device, wherein said TETS external coil assembly comprises first and second mating members capable of being selectively and removably coupled to each other, said first mating member removably attachable to a skin layer via an adhesive, and said second mating member comprises an encapsulated coil. Preferably said first mating member has a first coupling member able to be removably attached to a second coupling member disposed on said second mating member, at least one of said first and second coupling members being electrically non- conductive. According to another aspect there is provided a method for attaching a TETS external coil assembly to a skin layer, said method comprises a first step of adhering a first mating member to said skin layer by a means of adhesion, said first mating member comprising a first coupling member; and a second step of attaching a second mating member to said first mating member via a second coupling member disposed on said second mating member, said second coupling member capable of being selectively and removably coupled with said first coupling member, and said second mating member including an encapsulated coil.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:
Figure 1 is a schematic view of a TETS that may incorporate any of the embodiments of the present invention; Figure 2 is a transparent plan view of an external TET coil assembly in accordance with an embodiment of the present invention;
Figure 3 is a cross-sectional view of the coil assembly illustrated in Figure 2 taken on line 3-3;
Figure 4 is a plan view of a second connector for use with an embodiment of the present invention;
Figure 5 is a cross-sectional view of the second connector illustrated in Figure 4 taken on line 5-5;
Figure 6 is a plan view of another embodiment of a second connector; Figure 7 is a transparent plan view of another embodiment of an external TET coil assembly; Figure 8 is a cross-sectional view of the coil assembly illustrated in Figure 7 taken on line 8-8;
Figure 9 is a front elevation of a patient showing an implanted part of a TETS in dotted outline; Figures 10 and 11 illustrate the patient of Figure 9 further illustrating various components of at least one embodiment of the present invention;
Figures 12 and 13 are cross-sectional side elevations of the coil assembly illustrated in Figure 3 and the second connector illustrated in Figure 5 de-coupled and coupled, respectively; Figure 14 is a transparent plan view of an external TET coil assembly in accordance with another embodiment of the present invention;
Figure 15 is a plan view of an alternative embodiment of a second connector;
Figure 16 is a transparent plan view of another embodiment of an internal TET coil assembly; Figure 17 is a transparent plan view of another embodiment of an external
TET coil assembly; and
Figure 18 is a plan view of a coil for use with an external or internal TET coil assembly.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to Figure 1, a Transcutaneous Energy and/or Data Transfer System (TETS) is disclosed which comprises an internal, or implantable, transcutaneous energy and/or data transfer (TET) coil assembly 50 and an external TET coil assembly 51 which electrically interconnect components internally disposable within a patient with externally disposable components, where in use the implanted and external TET coil assemblies 50, 51 are separated by a skin layer SL of the patient.
In this example, the internal, or implantable, components comprise a blood pump 52, for example a left ventricular assist device (LVAD), connected by a lead Ll to an internal controller 53. The internal controller 53 includes a small battery, preferably a lithium ion rechargeable battery 54, encapsulated within a biocompatible housing 55, such as an injection moulded silicone housing, or a titanium housing. The internal controller 53 is electrically connected by a lead L2 to the internal TET coil assembly 50 which is mounted in parallel to and just beneath the skin layer SL of the patient. The blood pump 52 may be any type of blood pump. For example, it may be of a type implanted directly below the patient's heart, such as the VentrAssist®
LVAD by Ventracor Limited, Sydney Australia, or it may be implanted in the thoracic region of the patient, such as the pump disclosed in US-B-6530876. The internal TET coil assembly 50 may be implanted, for example, in the abdominal region of the patient, also as disclosed in US-B-6530876. However, the type and location of blood pump and internal TET coil assembly are not limited to these examples.
The internal TET coil assembly 50 is electrically inductively couplable to the external TET coil assembly 51 which in use is configured to occur across the patient's skin layer SL. The external TET coil assembly 51 is mounted at least approximately in parallel to the internal coil assembly 50 on the opposite, external side of the skin layer SL. It is preferred that the distance between the internal and external coil assemblies 50,51 is kept to a minimum to increase efficiency of energy and/or data transfer between the internal and external coil assemblies 50,51. The internal TET coil assembly 50 would therefore preferably be mounted immediately below the skin layer SL, and the external TET coil assembly 51 would preferably be mounted or positioned on or as close to the skin layer SL as possible.
The external TET coil assembly 51 is connectable by a lead 56 to an external controller 57, which includes a rechargeable battery, such as a lithium ion battery, to act as a power supply. The external controller 57 is also selectively connectable to an alternative power supply, such as mains power which is used either to supply power to the controller or to recharge the battery in the external controller 57. The external controller 57 is also connectable to a PC running a Graphical User Interface (GUI) 58, which may be used: to update the software components; download results and data; and/or adjust the operating parameters of the blood pump 52 or the overall system. Internal TET coil assembly 50 and external TET coil assembly 51 cooperate, when in use, to transmit electrical signals across the electrical gap made by the skin layer SL. The electrical signals transferred are one or both of energy/power supply or data. As will be understood, the TETS is configured to allow power supply to be directed from the external coil assembly 51 to the internal coil assembly 50, while data transmission can occur in both directions. When the external coil 51 is energised with an electrical current or signal, a reciprocal current or signal is generated in the implanted coil 50, thus allowing for the transmission of electrical power and signals.
A preferred embodiment is illustrated in Figures 2 to 5 where like reference numerals denote like parts. Figures 2 and 3 illustrate a TET coil assembly in the form of an external TET coil assembly 51. In this embodiment, the external TET coil assembly 51 includes an induction coil in the form of a coil 59 of electrically conductive wire encapsulated within a layer of corrosion resistant material that prevents or limits the ingress of fluid or oxidising agent to adversely affect the wire. Preferably, this first layer of material is poly-fluoro-acetate (PFA). The combination of PFA and copper wire is then injection moulded within a support in the form of a housing 60 of a biocompatible material, preferably flexible, such as silicon. In this embodiment, the coil 59 forms a generally planar, pancake, annular/torroidal shape having an external diameter of about 50mm, but which may be in the range of 30mm to 70mm, or more preferably 40mm to 60mm. The coil 59 of this embodiment has a central aperture or void region 61 having a diameter of about 20mm, but which may be in the range of 3mm to 40 mm, or more preferably 10mm to 30mm. The void region 61 generally increases the overall efficiency of transmission of the TETS. It may also reduce the heat generated by external coil 59.
In this embodiment, the coil 59 is formed from spiral windings of Litz wire due to its relatively low resistance and high conductivity. Depending on the gauge of the Litz wire, which for example may be about 16AWG to 22 AWG, the coil 59 may comprise about six to thirteen turns or windings. The coil 59 is integrally joined to lead 56 which encapsulates the beginning and end wires, 62a,b, joining the coil 59 at its beginning and end windings. The external TET coil assembly 51 is preferably connected to other electrical components by the use of the beginning and end wires 62a,b, which may also preferably be coated with PFA and then encapsulated within a silicone moulded sheath to form the lead 56. The lead 56 is, in this embodiment, silicon, however may be in any appropriate material. Whereas the beginning and end wires 62a ,b are illustrated in Figure 2 in two spaced and side-by- side parts, they may be braided or twisted together. Alternatively, the spiral windings may be formed from thin braided copper wire fashioned into a continuous coil.
The external TET coil assembly 51 comprises a first connector having a female couplable portion in the form of a female press stud connector or hole 63. In this embodiment, the hole 63 is centrally located with respect to the annular coil 59. The external TET coil assembly 51 also comprises a second connector in the form of an adhesive patch 66 comprising a male couplable portion in the form of a male press stud connector or post 64 being part of the adhesive patch 66, as illustrated in Figures 4 and 5. The hole 63 is configured for releasable non-magnetic physical connection to the post 64. In this embodiment, the physical connection is provided as a releasable snap-locking engagement with the post 64 of the adhesive patch 66. As illustrated in Figure 5, the post 64 of this embodiment comprises a head 68 and neck 70. The post 64 is configured such that the diameter of the head 68 of the post 64 is greater than the diameter of the hole 63. For the releasable snap-lock engagement to occur, the head 68 of the post 64 must be forced through the hole 63, such that when engaged, the bore 72 of the hole 63 rests about the neck 70.
The adhesive patch of this embodiment is an electrocardiogram (ECG) electrode, such as the "RED DOT®" electrode of 3M Company, Minnesota, USA, or of the type described in US-B-7,245,957. US-B-7,245,957 describes a medical snap- lock connector system, whereby an adhesive strip is adhered to the skin layer of a patient. The snap connector described in US-B-7,245,957 is adapted to be electrically conductive on the patient' s skin such that ECG equipment connected by leads to the adhesive strip can passively detect electrical signals generated by the patient's heart. The ability of these ECG electrodes to be electrically conductive on the patient's skin SL is not required for the present embodiment of the internal TET coil 50 to function. However, as will be understood using hindsight, it is convenient to be able to use such off the shelf adhesive patches in the present embodiment as they are typically readily available in hospitals and surgeries. Therefore, given that in use it is contemplated that the patient will likely replace the adhesive patch on a regular basis, for example from 2 or 3 times per day to 2 or 3 times per week, there can be a ready supply of adhesive patches 66 available to the patient.
The adhesive patch 66 comprises an adhesive layer 74 having an adhesive surface 76 with an adhesive substance thereon. Preferably, the adhesive substance is biocompatible to prevent or limit patient discomfort and also may be impermeable to water or at least resistant to water so that the adhesive layer 74 is not accidentally removed from the skin layer SL during normal washing. In this embodiment, the adhesive layer is breathable. The adhesive layer is mounted to a second layer 78 adapted to reinforce the overall structure of the adhesive patch 66, where the second layer 78 is less flexible than the adhesive layer 74. The post 64 is itself mounted to the second layer 78.
Whilst the adhesive layer 74 of the present embodiment is provided on the adhesive patch 66, it should be understood that in alternative embodiments the adhesive patch 66 may not be provided with an adhesive layer and the user will attach the adhesive patch by another "means of adhesion" such as a bio-compatible double- sided tape or by applying a bio-compatible compatible glue.
The adhesive patch of the above embodiment typically comprises an electrically conductive paste on the adhesive surface 76 and also the post 64 is itself electrically conductive. In alternative embodiments, it may be desirable to have a non-electrically conductive post 64 and/or no conductive paste on the adhesive surface. For example, the non-electrically conductive post 64 may comprise a material such as ceramic or suitable polymer. Also a central metal post 64 may act as a conductor during inductive energy transfer between the external TET coil assembly 51 and internal TET coil assembly 50 and heat up causing discomfort or, in some circumstances, damage to the patient's skin layer in the immediate vicinity of the adhesive patch 66. Electrically conductive connectors such as the post 64 may work with the present embodiment, but not as efficiently.
In an alternative embodiment, illustrated in Figure 6 where like reference numerals denote like parts, the patch 66 merely comprises a single layer 80 to which the post 64 is attached. In another alternative embodiment, the single layer 80 and post 64 are integrally formed, such that the single layer forms a flange from the post, the flange having an adhesive on its surface (not shown) opposite to the surface 82 with the post 64 for adhering to the patient. The single layer may be configured to be breathable to increase patient comfort.
Referring again to the external TET coil 51 illustrated in Figures 2 and 3, the hole 63 is formed in the silicon housing 60 either by being cut in the housing 60 or moulded therein. In an alternative embodiment, illustrated in Figures 7 and 8 where like reference numerals denote like parts, the hole is formed in the centre of a plastic insert 84 which is itself mounted within an aperture 85 in the silicon housing 60. In this embodiment, the plastic insert 84 is relatively less flexible than the silicon housing 60 and can provide a relatively stronger coupling fit with the post 64 compared with the hole of the previously described embodiments.
In this alternative embodiment of the external TET coil 51, the coil 59 is mounted on a backing plate 86. The backing plate 86 is preferably ferrite and fitted to the back of the external coil 59, to increase transfer efficiency of the EMF generated by the coil 59 when energised. The coil 59 and backing plate 86 being encapsulated in PFA which is in turn encapsulated in silicon to form the housing 60. Alternatively, the coil 59 and backing plate 86 are encapsulated in silicon only. While this embodiment has been described by combining the plastic insert 84 feature and the backing plate 86 feature, it will be understood that each feature may exist in alternative embodiments separate from each other.
The above described preferred embodiments will now be described in use, with reference to Figures 9 to 13, where like reference numerals denote like parts. Figure 9 illustrates a patient P with a blood pump 52 implanted such that it draws blood from the patient's heart H via inflow cannula 88 and returns it to the patient's aorta A via outflow cannula 90. The blood pump 52 is controlled by internal controller 53 which in this embodiment houses the battery. An internal TET coil assembly 50 is directly electrically connected to the internal controller 53 by lead L2 and is located in the patient's right sub-clavicle thoracic region. As will be understood, the internal TET coil assembly 50 in alternative embodiments may be positioned elsewhere, such as in the patient's abdominal area. Figure 10 illustrates the patient P with an adhesive patch 66 affixed to the skin layer of his chest directly over the site of the internal TET coil assembly 50. In practise, the patient P is able to feel the outline of the internal TET coil assembly 50 under his skin layer to be able to locate the adhesive patch 66 directly thereover or as close as possible thereto. Figure 11 illustrates the patient P with the external TET coil assembly 51 having been snap-lockingly coupled to the adhesive patch 66. In this illustration, the external TET coil assembly 51 is connected to external controller 57, which includes a battery therein, by lead 56. The external controller 57 may be carried by the patient in a suitable bag or sling. This overall configuration allows external TET coil assembly 51 to be positioned and aligned correctly with the internal TET coil assembly 50 without the need for positioning magnets that are commonly used in the prior art. The external TET coil assembly is securely positioned relative to skin layer by the adhesive patch 66. The external controller and battery 57 can then power and control the blood pump 52 via an inductive transcutaneous energy transfer between the external and internal TET coil assemblies 51, 50.
Figures 12 and 13 illustrate the snap-locking engagement or coupling between hole 63 and post 64 in more detail. As is illustrated in these Figures, adhesive patch 66 is affixed to the patient's skin layer SL with post 64 directed away from the skin layer SL. As illustrated in Figure 12, the hole 63 of the external TET coil assembly 51 is presented to the post 64. In Figure 13, the head 68 of the post 64 has been forced through the hole 63 to provide the snap-locking engagement. As will be understood, the external TET coil assembly 51 can be released or decoupled from the adhesive patch by forcing the head 68 of the post 64 back through the hole 63. This would release the inductive connection between the internal and external TET coil assemblies 50, 51 after which the internal battery 54 and internal controller 53 would take over powering and operating the blood pump 52. The patient can then enjoy untethered control of his blood pump 52 and may replace the adhesive patch if required or desired.
As will be understood, while the above embodiments have been described in relation to the use of snap-locking connectors, other forms of coupling members other than snap connectors may be used, which allows the first mating member to be selectively and removably attached to the second mating member. For example, complementary bayonet-style connectors or screw-threaded connectors may be employed centrally of the coil 59. With each of these embodiments of connections, accurate location of the external TET coil assembly with respect to the internal TET coil assembly can be achieved, given that they can only be affixed in one axial position. Also, the snap-locking connection may be arranged in other forms. For example, the hole 63 may take the form of a recess which does not pass entirely through the housing 60, but only partway through. In this case, the post 64, when coupled to the hole (recess) would be releasably retained in the housing 60. In this case, the recess may be shaped in a complementary fashion with respect to the post 64.
Figures 14 and 15 illustrate an alternative embodiment of the external TET coil assembly 51 where like reference numerals denote like parts. In this embodiment, the external TET coil assembly 51 comprises four circumferentially located holes 63' configured for snap-locking engagement with four complementarily spaced posts 64' on a corresponding adhesive patch 66'. The external TET coil assembly 51 can then be coupled to the patch 66' in four different radial positions on the patch 66 while maintaining the same relative axial position. Alternative arrangements of this embodiment may comprise more or fewer holes and posts 63, 64. For example, there may be two or more holes and posts 63, 64.
Whilst the abovementioned embodiments allow the TETS external coil assembly 51 to be operably connected to an internally disposed TETS internal coil assembly 50 without the use of magnets, it will be understood that in alternative embodiments the connectors of the abovementioned embodiments may be used in conjunction with a magnet arrangement. In such an arrangement, the use of stud connectors or other coupling members, means the magnets used may require less attractive force, than is employed in the prior art, or would be required by use of magnets alone, and therefore be less uncomfortable and detrimental to the patient, than the prior art magnets. Such magnets may preferably be disposed at or near the periphery of at least one of the mating members. One example of such an alternative embodiment is illustrated in Figures 16 and 17, where like reference numerals denote like parts, and where Figure 16 illustrates an external TET coil assembly 51 and Figure 17 illustrates an internal TET coil assembly 50. The internal TET coil assembly 50 comprises four magnets 92 circumferentially spaced about the internal coil 94. As will be understood, this embodiment of the internal TET coil assembly 50 is implanted in a patient in the same manner described above in relation to the previously described embodiments. The external TET coil assembly 51 illustrated in Figure 16 comprises a hole 63 for engagement with a patch 66 such as those described above. However, the external TET coil assembly 51 further comprises positioning magnets 100 for mutual magnetic connection with corresponding magnets 92 on the internal TET coil assembly 50. While the internal and external TET coils 50, 51 illustrated in Figure 16 and 17 comprise four and three magnets 92, 100 respectively, they may contain more or fewer magnets to provide different potential radial magnetic coupling orientations of the external TET coil assembly 51 with respect to the internal TET coil assembly 50 while maintaining the same relative axial position. As with the illustrations described above in relation to the external TET coil assemblies, while the internal coil 94 is illustrated as an annular disc in Figure 17, it is formed in practice by a flat spiral wound coil starting from lead wire 95 and ending with lead wire 96 and which defines a void 97 in the middle of the flat spiralled coil 94. An example of such a coil is illustrated in Figure 18, where like reference numerals denote like parts, which may form the coil of either the internal or external TET coil assembly 50,51.
The above embodiments have been described with reference to having a female connector on the external TET coil assembly 51 and a male connector on the adhesive patch 66. It will be understood that this is not a limitation and that the male connector may be located on external TET coil assembly 51 and the female connector may be located on the patch 66.
As will be understood, unless the context requires or suggests otherwise, features of any one of the above described embodiments may be used in conjunction with another one or more of the above described embodiments. While the invention has been described in reference to its preferred embodiments, it is to be understood that the words which have been used are words of description rather than limitation and that changes may be made to the invention without departing from its scope as defined by the appended claims. For example, the above description has been described in relation to TETS, however may be adapted for use in other energy transfer systems, particularly induction based energy transfer. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.
A reference herein to prior art information is not an admission that the information forms part of the common general knowledge in the art in Australia.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:-
1. A transcutaneous energy transfer (TET) coil assembly comprising: a support having an induction coil mounted thereon; and a first connector on or in the support for releasable non-magnetic physical connection to a second connector mountable to an external skin surface of a patient, wherein the TET coil assembly is configured for transcutaneous inductive coupling to a second TET coil assembly.
2. The assembly of claim 1 wherein the connectors comprise respective male and female couplable portions.
3. The assembly of claim 2 wherein the first connector comprises the female couplable portion.
4. The assembly of claim 2 or 3 wherein the male and female couplable portions are configured for releasable snap-locking engagement.
5. The assembly of any preceding claim wherein at least a portion of the first connector is at least approximately central of the induction coil.
6. The assembly of any preceding claim wherein the coil is annular or torroidal.
7. The assembly of any preceding claim wherein the induction coil is encapsulated by the support and the first connector is formed on or in the support.
8. The assembly of any preceding claim wherein the assembly comprises the second connector.
9. The assembly of any preceding claim wherein the second connector comprises an adhesive surface for adhesion to the external skin surface of the patient.
10. The assembly of any preceding claim comprising two or more first connectors.
11. The assembly of claim 10 wherein the two or more first connectors are spaced from a central region of the coil.
12. The assembly of any preceding claim comprising at least one other connector on the support other than the first connector, the at least one other connector comprising a magnetic device for magnetic connection to a magnetic device on or in the patient.
13. The assembly of claim 12 wherein the magnetic device on or in the patient is on the patient and associated with the second connector.
14. The assembly of any preceding claim wherein the assembly is configured for electrical connection to a controller and/or power supply for controlling/powering an implantable medical device via the second TET coil assembly.
15. A transcutaneous energy transfer (TET) coil assembly comprising: a support having an induction coil mounted thereon; a first connector on or in the support; and a second connector mountable to an external skin surface of a patient, wherein the first and second connectors are configured for releasable physical connection to each other, and the TET coil assembly is configured for transcutaneous inductive coupling with an internally located TET coil assembly.
16. The assembly of claim 15 wherein the connectors comprise respective male and female couplable portions.
17. The assembly of claim 16 wherein the first connector comprises the female couplable portion.
18. The assembly of claim 16 or 17 wherein the male and female couplable portions are configured for releasable snap-locking engagement.
19. The assembly of any one of claims 15 to 18 wherein the first connector is configured for releasable non-magnetic physical connection to the second connector.
20. The assembly of any one of claims 15 to 19 wherein at least a portion of the first connector is at least approximately central of the induction coil.
21. The assembly of any one of claims 15 to 20 wherein the coil is annular or torroidal.
22. The assembly of any one of claims 15 to 21 wherein the induction coil is encapsulated by the support and the first connector is formed on or in the support.
23. The assembly of any one of claims 15 to 22 wherein the second connector comprises an adhesive surface for adhesion to the external skin surface of the patient.
24. The assembly of any one of claims 15 to 23 comprising two or more first connectors.
25. The assembly of claim 24 wherein the two or more first connectors are spaced from a central region of the coil.
26. The assembly of any one of claims 15 to 25 comprising at least one other connector on the support other than the first connector, the at least one other connector comprising a magnetic device for magnetic connection to a magnetic device on or in the patient.
27. The assembly of claim 26 wherein the magnetic device on or in the patient is on the patient and associated with the second connector.
28. The assembly of any one of claims 15 to 27 wherein the assembly is configured for electrical connection to a controller and/or power supply for controlling/powering an implantable medical device via the second TET coil assembly.
29. A transcutaneous energy transfer (TET) system comprising: a first TET coil assembly implantable in a patient beneath a portion of a skin layer of a patient and connectable to an implantable medical device; and a second TET coil comprising the TET coil assembly of any one of claims 1 to 14 or 15 to 28.
30. An energy transfer coil assembly comprising: a support having an energy transfer coil mounted thereon; and a first connector on or in the support for releasable non-magnetic physical connection to a second connector mountable to an external skin surface of a patient, wherein the coil assembly is configured for electrical energy transfer coupling to a second energy transfer coil assembly.
31. The assembly of claim 30 wherein the connectors comprise respective male and female couplable portions.
32. The assembly of claim 31 wherein the first connector comprises the female couplable portion.
33. The assembly of claim 31 or 32 wherein the male and female couplable portions are configured for releasable snap-locking engagement.
34. The assembly of any one of claims 30 to 33 wherein at least a portion of the first connector is at least approximately central of the induction coil.
35. The assembly of any one of claims 30 to 34 wherein the coil is annular or torroidal.
36. The assembly of any one of claims 30 to 35 wherein the assembly comprises the second connector.
37. The assembly of any one of claims 30 to 36 wherein the second connector comprises an adhesive surface for adhesion to the external skin surface of the patient.
38. The assembly of any one of claims 30 to 37 wherein the energy transfer coil assembly comprises a transcutaneous energy transfer (TET) coil assembly.
39. The assembly of any one of claims 30 to 38 wherein the assembly is configured for electrical connection to a controller and/or power supply for controlling/powering an implantable medical device via the second coil assembly.
40. An energy transfer coil assembly comprising: a support having an energy transfer coil mounted thereon; a first connector on or in the support; and a second connector mountable to an external skin surface of a patient, wherein the first and second connectors are configured for releasable physical connection to each other, and the energy transfer coil assembly is configured for electrical coupling with an internally located transcutaneous energy transfer (TET) coil assembly.
41. A transcutaneous energy transfer system (TETS) external coil assembly for use with a TETS internal coil assembly implanted within a patient, operably connected to an implanted medical device, wherein said TETS external coil assembly comprises a first mating member and a second mating member, said first mating member is removably attachable to the skin layer of said patient by a means of adhesion, and said second mating member comprising an encapsulated coil, said first mating member and said second mating member each having a coupling member, the respective coupling members capable of being selectively and removably coupled to each other.
42. A transcutaneous energy transfer system (TETS) external coil assembly for use with a TETS internal coil assembly implanted within a patient, operably connected to an implanted medical device, wherein said TETS external coil assembly comprises first and second mating members capable of being selectively and removably coupled to each other, said first mating member removably attachable to a skin layer via an adhesive, and said second mating member comprises an encapsulated coil.
43. A method for attaching a transcutaneous energy transfer system
(TETS) external coil assembly to a skin layer, said method comprises a first step of adhering a first mating member to said skin layer by a means of adhesion, said first mating member comprising a first coupling member; and a second step of attaching a second mating member to said first mating member via a second coupling member disposed on said second mating member, said second coupling member capable of being selectively and removably coupled with said first coupling member, and said second mating member including an encapsulated coil.
PCT/AU2008/001302 2007-09-03 2008-09-03 Transcutaneous energy transfer coil assembly WO2009029977A1 (en)

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AU2007904754 2007-09-03

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US9855376B2 (en) 2014-07-25 2018-01-02 Minnetronix, Inc. Power scaling
US10149933B2 (en) 2014-07-25 2018-12-11 Minnetronix, Inc. Coil parameters and control
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US10342908B2 (en) 2015-01-14 2019-07-09 Minnetronix, Inc. Distributed transformer
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