Patent Description:
Medical devices, and especially active implantable medical devices, contain electrodes to electrically stimulate body tissue such as muscles and nerves.

The electrical contacting of an electrical conductor to an electrode can often be a major challenge, in particular if dimensions are small such as in medical devices which are introduced in the human or animal body. Furthermore, e.g., good electrical conductivity and mechanical stability even upon exposure to strong loads over an extended period of time are desired. Another very important feature is the reliability of medical devices such as, e.g., cardiac pacemakers, implantable cardioverters, defibrillation devices, and cardiac resynchronisation devices, particularly with a view to keeping the material fatigue as low as possible. In particular the electrical conductor and the connection to the electrode are exposed to strong loads in operation. Since invasive surgery is commonly required in order to introduce medical devices into the body or to remove or replace parts thereof, the individual components of the device are therefore desired to have a long service life in order to reduce the need for surgical interventions.

Methods for connecting an electrical conductor to an electrode are known in the art. For example, <CIT> refers to a method for connecting a strand of a multi-strand cable to an electrode of an implantable medical device. The method includes cutting a strand of a multi-strand cable, lifting at least one of the free ends, stripping the end of the lifted strand, placing an electrode around the multi-strand cable to partially cover the end of the lifted and stripped stand, and connecting at least one portion of the stripped end of the strand to the electrode. <CIT> refers to a medical lead, comprising a lead body having a seam-less insulator between a proximal end and a distal end of the lead body and having at least one conductor; at least one band electrode secured between the proximal and distal end of the lead body and electrically connected to the conductor; and at least one band connector secured between the proximal and distal end of the lead body and electrically connected to the conductor. <CIT> discloses an electrophysiology catheter comprising: a catheter tube having a band of electrically conductive material extending around substantially the entire circumference of said catheter tube, said conductive material being non-adhesive; a flexible electrical conductor within said catheter tube, said electrical conductor having a free end extending through an opening in said catheter tube, said free end lying along a portion of said band of non-adhesive electrically conductive material, said free end being in electrical contact with said band of non-adhesive electrically conductive material; and an electrically conductive electrode positioned over and in electrical contact with said band of non-adhesive electrically conductive material and said free end of said conductive wire, said electrode being substantially cylindrical and having a distal end and a proximal end. <CIT> refers to a method of manufacturing a biological electrical stimulus cable assembly, comprising a) providing a cable portion, including a plurality of first conductive wires set into a length of insulative material having a surface, wherein the plurality of conductive wires are disposed at substantially the same radial depth within the insulative material, wherein the wires are encapsulated within the insulative material that forms a body of the cable portion; b) removing a portion of said insulative material from said surface of said length of insulative material to only a first one of said first conductive wires at a first location, thereby creating a first exposed first Wire surface and removing a portion of said insulative material from said surface of said length of insulative material, also only to said first one of said first conductive wires at a second location, thereby creating a second exposed first wire surface, wherein the removing is performed on the cable portion after the first conductive wires have been set within the insulative material of the body of the cable portion; c) electrically connecting a second conductive wire to said first exposed first wire surface; and d) wrapping said second conductive wire about said cable portion and connecting it to said second exposed first wire surface, thereby creating & circumscribing electrode, wherein the second conductive wire is welded to the first one of said first conductive wires at the second exposed first wire surface. <CIT> discloses a system for reception and/or emission of an electrical signal from or into the human or animal body, comprising at least one insulated electrical conductor; a sleeve-shaped electrode that is electrically connected to the electrical conductor and comprises an internal side an external side, a channel, and an opening in a wall of the channel; whereby the channel defines a longitudinal axis along which the conductor is arranged in the channel, characterised in that a material of the electrode surrounds the entire circumference of the opening; the electrical conductor is guided through the opening between the internal side and the external side of the opening transverse to the longitudinal axis of the channel; and the electrical conductor is connected to the electrode within the opening directly in firmly-bonded and/or force-locking manner such that a durable mechanical and electrical connection between the electrical conductor and the electrode is established. <CIT> refers to a medical electrode suitable for capacitive coupling to a patient, the medical electrode comprising: a dielectric layer having a first side and a second side; conductive ink carried by the first side of the dielectric layer, with the conductive ink comprising a plurality of similarly shaped, sequentially arranged sections; and a conductive gel connected to and carried by the second side of the dielectric layer opposite said plurality of sections of conductive ink; in which capacitances formed between each section of the conductive ink and conductive gel coating combine to form a total capacitance of the electrode.

Conventional methods have the drawback that the whole electrical conductor including the insulation is cut in order to connect the electrical conductor to the electrode. However, it is typically not possible to properly connect the electrical conductor to the electrode in a flush-fitted manner such that parts of the cut electrical conductor are in contact with surrounding materials. This may result in decreased electrical conductivity and service life.

In view of the above, there is still a need for an electrode-electrical conductor system for a medical device. Furthermore, it is desired that the electrical conductor includes selective openings such that the electrode can be assembled via these openings in a flush-fitted manner.

It is additionally desired that the electrode-electrical conductor system can be easily manufactured, i.e. without complex manufacturing steps and equipment.

Therefore, the present invention is directed to the provision of an improved, or at least alternative, electrode-electrical conductor system for a medical device and a method for preparing such an electrode-electrical conductor system for a medical device.

The foregoing and other objects are solved by the subject-matter as defined in the independent claims. Advantageous embodiments of the present invention are defined in the corresponding subclaims.

The invention provides an electrode-electrical conductor system for a medical device comprising a) at least one electrical conductor comprising one or more electrically insulated wire(s) or cable(s), wherein the electrical insulation comprises two or more partial openings, which are arranged on one side of the wire(s) or cable(s), and b) two or more electrodes, which are mechanically and electrically connected to the wire(s) or cable(s) via the two or more partial openings arranged on one side of the wire(s) or cable(s) by welding, pressing, swaging, adhesives, brazing, soldering and/or dimples, characterised in that the electrical conductor is embedded in a polymer substrate, wherein the polymer substrate is a biocompatible polymer substrate (<NUM>), which is selected from the group comprising polyurethane, thermoplastic polyurethane (TPU), silicone, polyimide, phenyltrimethoxysilane (PTMS), polymethylmethacrylate (PMMA), parylene, polyetheretherketone (PEEK), liquid-crystal polymer (LCP), kapton and mixtures thereof, and comprises one or more opening(s) arranged on the two or more partial openings on one side of the wire(s) or cable(s).

The inventors surprisingly found out that the electrode-electrical conductor system is suitable for a medical device. Furthermore, the electrode can be assembled to the electrical conductor via selective partial openings in a flush-fitted manner. Moreover, it has been found out that the partial opening of the electrical insulation is of great advantage as it increases the dielectric strength/resistance against electrical short circuits towards other insulated conductors within the electrode-electrical conductor system. Moreover, the electrode-electrical conductor system can be easily manufactured without complex manufacturing steps and equipment.

According to one embodiment, the electrical conductor comprises one or more bundle(s) or strand(s) of electrically insulated wire(s) or cable(s), preferably each of the one or more bundle(s) or strand(s) of electrically insulated wire(s) or cable(s) is/are covered by an electrical insulation, which, if present, comprises one or more opening(s) arranged on the two or more partial openings on one side of the wire(s) or cable(s).

According to one embodiment, the wire(s) or cable(s) of the electrical conductor and/or the at least two electrodes comprise(s) one or more of the metals Pt, Ir, Ta, Pd, Ti, Fe, Au, Mo, Nb, W, Ni, Ti, Ag, Cu, or a mixture and/or alloy thereof and/or the electrical conductor and/or the at least two electrodes is/are a multilayered material system(s).

According to one embodiment, the electrical insulation of the electrical conductor comprises an insulating plastic material, preferably an insulating plastic material selected from the group comprising polyethylene, polyurethane, polyimide, polyamide, PEEK, and fluorinated plastic materials such as ETFE, PTFE, PFA, PVDF, FEP or FPO, and mixtures thereof.

According to one embodiment, the wire(s) or cable(s) has/have a thickness in the range from <NUM> to <NUM>, preferably from <NUM> to <NUM>, and/or the electrical insulation of the wire(s) or cable(s) has/have a thickness in the range from <NUM> to <NUM>, preferably from <NUM> to <NUM>.

According to one embodiment the wire(s) or cable(s) within the two or more partial openings is/are mechanically or laser cut such that one or both of the free ends of the cut wire(s) or cable(s) is/are connected to the two or more electrodes.

According to one embodiment, one or both of the free ends of the cut wire(s) or cable(s) is/are pressed or welded.

According to one embodiment, the two or more electrodes are selected from a cubic, rectangular, cylindrical and ring electrode and ring electrode segment, preferably a ring electrode or ring electrode segment.

The electrical conductor is embedded in a biocompatible polymer substrate, which is selected from the group comprising polyurethane, thermoplastic polyurethane (TPU), silicone, polyimide, phenyltrimethoxysilane (PTMS), polymethylmethacrylate (PMMA), parylene, polyetheretherketone (PEEK), liquid-crystal polymer (LCP), kapton and mixtures thereof, comprising one or more opening(s) arranged on the two or more partial openings on one side of the wire(s) or cable(s).

According to a further aspect, a method for preparing an electrode-electrical conductor system for a medical device as defined herein is provided, the method comprising the steps of.

According to one embodiment, the method comprises a further step of cutting the one or more wire(s) or cable(s) by laser cutting or mechanical cutting to obtain two free ends at the cut of the wire(s) or cable(s) before attaching the two or more electrodes to the two or more partial openings of the at least one electrical conductor.

According to one embodiment, the method comprises a further step of lifting one or both of the free ends relative to the rest of the one or more wire(s) or cable(s) before attaching the two or more electrodes to the two or more partial openings of the at least one electrical conductor.

According to one embodiment, the partial opening of the electrical insulation by laser ablation or mechanical cutting is carried out such that the wire(s) or cable(s) are uncut, and/or the further step of cutting the one or more wire(s) or cable(s) by laser cutting or mechanical cutting is carried out such that the remaining electrical insulation surrounding the wire(s) or cable(s) is uncut.

According to one embodiment, the method comprises a further step of pressing or welding one or both of the free ends, preferably both of the free ends.

According to one embodiment, step b) further comprises opening a polymer substrate in which the electrical conductor is embedded by laser ablation or mechanical cutting.

It should be understood that for the purposes of the present invention, the following terms have the following meanings:
Where an indefinite or definite article is used when referring to a singular noun, e.g., "a", "an" or "the", this includes a plural of that noun unless anything else is specifically stated.

Where the term "comprising" is used in the present description and claims, it does not exclude other elements. For the purposes of the present invention, the terms "essentially consisting of" and "consisting of" are considered to be a preferred embodiment of the term "comprising". If hereinafter a group is defined to comprise at least a certain number of embodiments, this is also to be understood to disclose a group, which preferably essentially consists of only of these embodiments, or preferably consists of only of these embodiments.

Terms like "obtainable" or "definable" and "obtained" or "defined" are used interchangeably. This, for example, means that, unless the context clearly dictates otherwise, the term "obtained" does not mean to indicate that, for example, an embodiment must be obtained by, for example, the sequence of steps following the term "obtained" though such a limited understanding is always included by the terms "obtained" or "defined" as a preferred embodiment.

Whenever the terms "including" or "having" are used, these terms are meant to be equivalent to "comprising" as defined hereinabove.

The following schematic drawings show aspects of the invention for improving the understanding of the invention in connection with some exemplary illustrations, wherein.

One aspect of the present invention refers to an electrode-electrical conductor system for a medical device comprising a) at least one electrical conductor comprising one or more electrically insulated wire(s) or cable(s), wherein the electrical insulation comprises two or more partial openings, which are arranged on one side of the wire(s) or cable(s), and b) two or more electrodes, which are mechanically and electrically connected to the wire(s) or cable(s) via the two or more partial openings arranged on one side of the wire(s) or cable(s) by welding, pressing, swaging, adhesives, brazing, soldering and/or dimples, characterised in that the electrical conductor is embedded in a polymer substrate, wherein the polymer substrate is a biocompatible polymer substrate (<NUM>), which is selected from the group comprising polyurethane, thermoplastic polyurethane (TPU), silicone, polyimide, phenyltrimethoxysilane (PTMS), polymethylmethacrylate (PMMA), parylene, polyetheretherketone (PEEK), liquid-crystal polymer (LCP), kapton and mixtures thereof, and comprises one or more opening(s) arranged on the two or more partial openings on one side of the wire(s) or cable(s).

It is thus required that the electrode-electrical conductor system comprises at least one electrical conductor.

The term "at least one" electrical conductor in the meaning of the present invention means that the electrical conductor comprises, preferably consists of, one or more electrical conductor(s). In one embodiment of the present invention, the electrical conductor comprises, preferably consists of, one electrical conductor. Alternatively, the electrical conductor comprises, preferably consists of, two or more electrical conductors. For example, the electrical conductor comprises, preferably consists of, one electrical conductor.

It is further appreciated that the at least one electrical conductor comprises one or more electrically insulated wire(s) or cable(s). That is to say, each electrical conductor comprises one or more electrically insulated wire(s) or cable(s).

It is to be noted that a cable is a regular structure of multiple wires, which are twisted.

In one embodiment, the electrically insulated wire or cable has a thickness ranging from <NUM> to <NUM>, preferably ranging from <NUM> to <NUM>.

It is to be noted that the wire(s) or cable(s), i.e. without electrical insulation, preferably has/have a thickness in the range from <NUM> to <NUM>, preferably from <NUM> to <NUM>.

Additionally or alternatively, the electrical insulation of the wire(s) or cable(s) has/have a thickness in the range from <NUM> to <NUM>, preferably from <NUM> to <NUM>.

In one embodiment, the wire(s) or cable(s), i.e. without electrical insulation, has/have a thickness in the range from <NUM> to <NUM>, preferably from <NUM> to <NUM> or the electrical insulation of the wire(s) or cable(s) has/have a thickness in the range from <NUM> to <NUM>, preferably from <NUM> to <NUM>. In a preferred embodiment, the wire(s) or cable(s), i.e. without electrical insulation, has/have a thickness in the range from <NUM> to <NUM>, preferably from <NUM> to <NUM> and the electrical insulation of the wire(s) or cable(s) has/have a thickness in the range from <NUM> to <NUM>, preferably from <NUM> to <NUM>.

It is to be noted that the one or more electrically insulated wire(s) or cable(s) can be round cable(s) or wire(s), i.e. the thickness of the cable(s) or wire(s) in all dimensions is almost the same. Alternatively, the one or more electrically insulated wire(s) or cable(s) can be flat cable(s) or wire(s), i.e. the thickness of the cable(s) or wire(s) in one dimension is reduced compared to the other dimensions.

In a preferred embodiment, the one or more electrically insulated wire(s) or cable(s) is a/are round cable(s) or wire(s).

The at least one electrical conductor comprises one or more electrically insulated wire(s) or cable(s). Accordingly, the at least one electrical conductor comprises one or more metal wire(s) or cable(s) and an insulation or consists of one or more metal wire(s) or cable(s) and an insulation. In some embodiments, the at least one electrical conductor comprises one or more of the metals Pt, Ir, Ta, Pd, Ti, Fe, Au, Mo, Nb, W, Ni, Ti, Ag, Cu, or a mixture and/or alloy thereof. In some embodiments, the at least one electrical conductor comprises Pt alloys such as Ptlr10 and PtIr20, or the alloys MP35N, MP35N-Ag, <NUM>, <NUM>, SST (stainless steel) or nitinol.

Preferably, the at least one electrical conductor comprises MP35, Cu, Au, Ta, Pt, Ir or Pd. In some embodiments, the electrically conductive part of the at least one electrical conductor consists of MP35N, MP35N-Ag, SST (stainless steel), Cu, Au, Ta, Pt, Ir or Pd or alloys of said metals. In some embodiments, the at least one electrical conductor contains less than <NUM>%, <NUM>% or less than <NUM>% Fe.

MP35N is a nickel-cobalt-based hardenable alloy. A variant of MP35N is described in the industrial standard ASTM F562-<NUM>. In one embodiment, MP35N is an alloy that comprises <NUM> to <NUM>% Co, <NUM> to <NUM>% Cr, <NUM> to <NUM>% Mo, and <NUM> to <NUM>% Ni.

Ptlr10 is an alloy made of <NUM> to <NUM> % platinum and <NUM> to <NUM> % iridium.

PtIr20 is an alloy made of <NUM> to <NUM> % platinum and <NUM> to <NUM> % iridium.

<NUM> is an acid-resistant, CrNiMo austenitic steel with approx. <NUM>% Cr; approx. <NUM>% Ni and at least <NUM> % Mo. One variant of <NUM> is described in the industrial standard EN <NUM>-<NUM>. In one embodiment, <NUM> is an alloy that comprises <NUM> to <NUM>% Cr, <NUM> to <NUM>% Mo, and <NUM> to <NUM>% Ni.

<NUM> is a chromium-nickel steel with high corrosion resistance. One variant of <NUM> is described in the industrial standard DIN <NUM>. In one embodiment, <NUM> is an alloy that comprises <NUM> to <NUM>% Cr and <NUM> to <NUM>% Ni.

Nitinol is a nickel-titanium alloy with a shape memory with an ordered-cubic crystal structure and a nickel fraction of approximately <NUM>%, whereby titanium accounts for the remaining fraction. Nitinol has good properties with regard to biocompatibility and corrosion resistance.

Unless specified otherwise, all percentages given herein shall be understood to be mass percentages (weight%).

It is appreciated that the at least one electrical conductor should have a high electrical conductivity and low electrical resistance. Thus, the at least one electrical conductor preferably comprises one or more wire(s) or cable(s) made from Pt or Pt alloy, MP35N, MP35N-Ag, or SST (stainless steel).

The at least one electrical conductor may also comprise multilayered material systems.

It is preferred that the electrically conductive part of the at least one electrical conductor, i.e. the wire or cable, consists of one or more of said materials and an insulation.

The at least one electrical conductor is electrically insulated, preferably by an insulating plastic material. In as far as multiple electrical conductors or more than one electrically insulated wire(s) or cable(s) are present, these comprise no electrical connection to each other. In some embodiments, the at least one electrical conductor comprises a dielectric sheathing, for example made of an electrically insulating plastic material, silicone or rubber. Suitable insulating plastic materials are selected from the group comprising polyethylene, polyurethane, polyimide, polyamide, PEEK, and fluorinated plastic materials such as ETFE, PTFE, PFA, PVDF, FEP or FPO, and mixtures thereof. Preferably, the insulating plastic material is selected from the group comprising polyurethane and fluorinated plastic materials such as ETFE, PTFE or PFA.

A plurality of electrically insulated wire(s) or cable(s) can be arranged into a conductor bundle or strand. It is also appreciated that the electrical conductor may comprise several bundle(s) or strand(s) of electrically insulated wire(s) or cable(s).

In one embodiment, the electrical conductor thus comprises one or more bundle(s) or strand(s) of electrically insulated wire(s) or cable(s).

It is appreciated that the term "bundle" refers to multiple wires or cables which are randomly bundled. The term "strand" refers to multiple wires or cables which are regular twisted structures.

For the sake of completeness, it is to be noted that each wire or cable in such a bundle or strand is electrically insulated. Thus, the at least one electrical conductor may be in the form of a bundle or strand of electrically insulated wire(s) or cable(s), wherein each wire or cable is electrically insulated.

It is also possible that each of the one or more bundle(s) or strand(s) of electrically insulated wire(s) or cable(s) is surrounded by an outer electrical insulation covering each of the one or more bundle(s) or strand(s) of electrically insulated wire(s) or cable(s). Such an outer insulation preferably has a thickness in the range from <NUM> to <NUM>, preferably from <NUM> to <NUM>.

It is to be noted that the thickness of such an outer insulation of the bundle(s) or strand(s) can be adjusted to the electrode used in order to avoid e.g. assembling of bridging or spacer elements.

It is further to be noted that the electrical insulation of the at least one electrical conductor comprises two or more partial openings which are arranged on one side of the wire(s) or cable(s). That is to say, the two or more partial openings are such that they are only partially surrounding the wire(s) or cable(s), i.e. the electrical insulation surrounding the at least one electrical conductor is not completely removed.

The two or more partial openings are suitable for mechanically and electrically connecting the at least two electrodes of the electrical conductor of the electrode-electrical conductor system.

The number of partial openings in the electrical insulation of the at least one electrical conductor depends on the number of electrodes connected to the at least one electrical conductor.

The at least one electrical conductor includes two or more partial openings, e.g. two to ten partial openings, in the electrical insulation of the at least one electrical conductor. In this case, two or more, e.g. two to ten, electrodes are connected to the at least one electrical conductor.

Thus, it is preferred that the number of partial openings in the electrical insulation of the at least one electrical conductor corresponds to the number of electrodes connected to the at least one electrical conductor.

If the electrode-electrical conductor system comprises more than one electrical conductor, it is appreciated that each electrical conductor may include a different number of partial opening(s), i.e. also a different number of electrodes. However, it is preferred that each electrical conductor in such an arrangement includes the same number of partial opening(s).

It is preferred that the electrode surrounds the entire circumference of the partial opening of the at least one electrical conductor to which the electrode is connected to. This is advantageous in that the wire(s) or cable(s) within the electrical conductor are not exposed to surrounding materials such as tissue resulting in increased electrical conductivity and service life. Thus, the length and diameter of the partial openings is preferably adjusted to the length and diameter of the electrode connected to the electrical conductor.

In one embodiment, the partial openings comprises a varying diameter. For example, the openings can be cone-shaped.

In one embodiment, the diameter of the partial openings is in the range from <NUM> to <NUM>, preferably from <NUM> to <NUM>.

For example, the diameter of the partial openings corresponds to the diameter of the wire(s) or cable(s) within the electrical conductor. Alternatively, the diameter of the partial openings corresponds to the diameter of electrically insulated wire(s) or cable(s). Preferably, the diameter of the partial openings corresponds to the diameter of the wire(s) or cable(s) within the electrical conductor.

It is appreciated the size and shape of the two or more partial openings is selected in a way that the part of the electrical insulation of the at least one electrical conductor, which is in contact with the electrical insulation of an electrical conductor of another conducting channel, remains intact. Thus, the remaining electrical insulation layer of the at least one electrical conductor, which e.g. points radially inwards to the (center of the wire or cable) or points towards the electrical conductor(s) of another conducting channel is intact and functional. Thereby, the dielectric strength/resistance against electrical short circuits is increased. This is one important finding by the inventors.

According to one embodiment, the size of the one or more partial openings in the electrical insulation layer of the at least one electrical conductor, as seen in a cross section, does not exceed <NUM>%, preferably <NUM>%, more preferably <NUM>%, of the perimeter of the at least one electrical conductor.

As already mentioned above, the electrical conductor may comprise one or more bundle(s) or strand(s) of electrically insulated wire(s) or cable(s). In this embodiment, each of the one or more bundle(s) or strand(s) of electrically insulated wire(s) or cable(s) is preferably surrounded by an outer electrical insulation covering each of the one or more bundle(s) or strand(s) of electrically insulated wire(s) or cable(s).

If such outer insulation is present, it is appreciated that the outer insulation of the one or more bundle(s) or strand(s) comprise(s) one or more opening(s) arranged on the two or more partial openings on one side of the wire(s) or cable(s). That is to say, the opening(s) in the outer insulation of the one or more bundle(s) or strand(s) encompass(es) the partial openings of the electrical conductor. The opening(s) in the outer insulation of the one or more bundle(s) or strand(s) can be flush-fitted to the partial openings)of the electrical conductor or the opening(s) in the outer insulation of the one or more bundle(s) or strand(s) can be broader in diameter than the partial openings of the electrical conductor. The later one has the advantage that the wire(s) or cable(s) within the electrical conductor can be better reached such that this embodiment is preferred. If such outer insulation is present, it is preferred that the outer insulation is ablated or cut circumferentially. This is advantageous as a pocket in the outer insulation is created, which receives the ring-electrode/electrode-segment, such that an isodiametric transition is ensured.

Another required component of the electrode-electrical conductor system is at least two electrodes.

The term "at least two" electrodes in the meaning of the present invention means that the electrode comprises, preferably consists of, two or more electrodes.

The electrode comprises, preferably consists of, two or more electrodes.

The type of electrode is not particularly limited as long as the electrode is suitable for use in a medical device. For example, the two or more electrodes are selected from a cubic, rectangular, cylindrical and ring electrode and ring electrode segment. Preferably, the two or more electrodes are a ring electrode or a ring electrode segment.

The electrode is a conductive and electrically conductive element, which can be attached appropriately to the at least one electrical conductor or conductor bundle.

In some embodiments, the at least two electrodes comprises one or more of the metals Pt, Ir, Ta, Pd, Ti, Fe, Au, Mo, Nb, W, Ni, Ti, Ag, Cu, or a mixture and/or alloy thereof. It is to be noted that the at least two electrodes may be in contact with tissue and thus, it is especially preferred that it is made of a biocompatible material. In view of this, it is preferred that the at least two electrodes comprise the alloys MP35N, PtIr20, PtIr10, PdIr10, <NUM>, or <NUM>. The electrode can just as well comprise multilayered material systems. In one embodiment, the electrode consists of one or more of said materials.

In view of the different needs in terms of high electrical conductivity and teak resistance of the at least one electrical conductor on one side and the high biocompatibility of the at least two electrodes on the other side, it is preferred that the at least one electrical conductor, i.e. the conductive part of the electrical conductor, and the at least two electrodes comprise different materials.

Thus, it is preferred that the electrically conductive part of the at least one electrical conductor preferably consists of Cu, Pt alloys such as PtIr20 and PtIr10, or the alloys MP35N, MP35N-Ag, SST (<NUM>, <NUM>), whereas the at least two electrodes comprise the alloys MP35N, PtIr20, Ptlr10, Pdlr10, <NUM>, or <NUM>.

In one embodiment, the at least two electrodes have an external diameter of less than <NUM>, preferably in the range from <NUM> to <NUM> and more preferably from <NUM> to <NUM>.

Additionally or alternatively, the at least two electrodes have a length ranging from <NUM> to <NUM> and more preferably from <NUM> to <NUM>.

It is further to be noted that the electrical insulation of the at least one electrical conductor comprises two or more partial openings suitable for mechanically and electrically connecting the at least two electrodes of the electrode segment to the at least one electrical conductor of the electrical conductor segment. The mechanical and electrical connection between the at least two electrodes and the at least one electrical conductor of the electrical conductor segment can be achieved by welding, pressing, swaging, adhesives, brazing, soldering and/or dimples.

For example, the at least two electrodes are mechanically and electrically connected to the at least one electrical conductor by welding, pressing, swaging, adhesives, brazing, soldering and/or dimples which are pressed through the partial openings of the electrical insulation of the at least one electrical conductor. The connection is preferably the same for all connections present.

The mechanical and electrical connection between the at least two electrodes and the at least one electrical conductor is preferably achieved by welding, pressing, brazing and/or soldering such as soft soldering. Additionally or alternatively, the mechanical and electrical connection between the at least two electrodes and the at least one electrical conductor can be achieved by adhesives and/or dimples which are pressed through the partial openings of the electrical insulation of the at least one electrical conductor.

Preferably, the mechanical and electrical connection between the at least two electrodes and the at least one electrical conductor is achieved by only one means, i.e. by welding, pressing, swaging, adhesives, brazing, soldering and/or dimples which are pressed through the partial openings of the electrical insulation of the at least one electrical conductor.

In one embodiment, the mechanical and electrical connection between the at least two electrodes and the at least one electrical conductor in a firmly-bonded manner. In this case, the mechanical and electrical connection between the at least two electrodes and the at least one electrical conductor is preferably a welded connection. Said welded connection can be attained, for example, by laser welding. The melting of the conductor in the course of welding can be used to completely close the partial opening within the ring electrode. By this means, the ingress of liquids or other contaminations into the partial opening can be prevented. Moreover, sharp edges or burrs on the external side of the partial opening can be covered and therefore smoothed.

Having an exclusively firmly-bonded connection results in a very stable, durable and very conductive connection between the electrical conductor and the electrode.

In one embodiment, the mechanical and electrical connection between the at least two electrodes and the at least one electrical conductor is achieved in a force-locking manner. Said force-locking connection can be achieved by e.g. dimples or other mechanical pressing methods known in this field. Several suitable methods are described in <CIT>. Comparable methods known in this context to a person skilled in the art can be used as well.

In one embodiment, the mechanical and electrical connection between the at least two electrodes and the at least one electrical conductor is achieved in a direct firmly-bonded manner. In one embodiment, the mechanical and electrical connection between the at least two electrodes and the at least one electrical conductor is achieved in a direct force-locking manner. In one embodiment, the mechanical and electrical connection between the at least two electrodes and the at least one electrical conductor is achieved in a direct firmly-bonded as well as a direct force-locking manner. In one embodiment, the mechanical and electrical connection between the at least two electrodes and the at least one electrical conductor is achieved in a direct firmly-bonded manner, but not in a force-locking manner.

It is to be noted that the at least one electrical conductor is preferably connected to the at least two electrodes within the opening in a form-fitting manner.

In one embodiment, the at least one electrical conductor is connected to the at least two electrodes in a firmly-bonded manner, but not in a force-locking manner. The at least one electrical conductor can just as well be connected to the at least two electrodes exclusively in a firmly-bonded manner.

In one embodiment, the at least two electrodes are micro-structured, i.e. they comprise surface structures, or a coating. Said surface structures can impart a higher and precisely defined roughness to the electrode surface. The surface structures can be generated even before connecting the at least two electrodes to the at least one electrical conductor as they are not affected by a force-locking connection. It is also possible to micro-structure the at least two electrodes after attaching it to the at least one electrical conductor.

Similarly, it is feasible to use coated electrodes. Said coatings are preferably used if the mechanical and electrical connection between the at least two electrodes of the electrode segment and the at least one electrical conductor of the electrical conductor segment is of an exclusively firmly-bonded manner. Such a coating is not affected by the inventive contacting of the at least one electrical conductor to the at least one electrode.

The at least two electrodes can be structured, for example, by means of a laser. In one embodiment, the surface of the at least two electrodes is enlarged by roughening the surface. This can take place with a variety of methods, for example by means of a laser.

A coating can be affected, for example, by means of PVD, CVD or electrochemical deposition, which methods are well known to the skilled person. TiN, Ir, IrOx, Pt or conductive polymers, for example conductive polymers based on thiophene, such as, for example, poly-<NUM>,<NUM>-ethylenedioxythiophene (PEDOT) or the conductive polymers described in <CIT>, can be used for said coating.

In one embodiment, the electrode-electrical conductor system comprises a multitude of electrodes, wherein each is electrically and mechanically connected to exactly one of the electrical conductors, such that the multitude of electrodes can be electrically addressed independent of each other. This means that each of the multitude of electrodes is set up to receive an electrical signal exclusively from exactly one electrical conductor or to emit an electrical signal to said electrical conductor, but not to any of the other electrical conductors. Accordingly, each electrode can be electrically triggered independent of the other electrodes.

In one embodiment, other than the direct connection between the at least one conductor and the at least one electrode, there is no further component present that connects the at least one electrical conductor to the at least one electrode in order to establish an electrical and mechanical connection between them. According to one embodiment, a welded or soldered connection or a material forming a connection of this type shall not be understood to be a "component" in this context. A component of this type could, e.g., be an adhesive or dimples, which is attached to the wire or cable of the at least one electrical conductor in order to subsequently connect it to the at least one electrode.

It is appreciated that the at least one electrical conductor is embedded in a polymer substrate.

For example, the at least one electrical conductor is partially embedded in the polymer substrate. Alternatively, the at least one electrical conductor is essentially completely embedded in the polymer substrate. That is to say, the at least one electrical conductor is preferably essentially completely surrounded by the polymer substrate.

In one embodiment, the at least one electrical conductor together with the two or more electrodes connected thereto is embedded in a polymer substrate.

For example, the at least one electrical conductor together with the two or more electrodes connected thereto is partially embedded in the polymer substrate. Alternatively, the at least one electrical conductor together with the two or more electrodes connected thereto is essentially completely embedded in the polymer substrate. That is to say, the at least one electrical conductor together with the two or more electrodes connected thereto is preferably essentially completely surrounded by the polymer substrate.

If the at least one electrical conductor together with the two or more electrodes connected thereto is partially embedded in the polymer substrate, it is preferred that the at least one electrical conductor is partially or essentially completely surrounded by the polymer substrate, whereas the two or more electrodes connected thereto is not embedded in the polymer substrate.

The polymer substrate is a biocompatible polymer substrate.

The term "biocompatible" in the meaning of the present invention is meant to refer to a material which is considered by a person skilled in the art to be safe when being in contact with a living organism (e.g. a human or animal) over a specific period of time (e.g. when used in an implantable medical device).

The biocompatible polymer substrate is selected from the group comprising polyurethane, thermoplastic polyurethane (TPU), silicone, polyimide, phenyltrimethoxysilane (PTMS), polymethylmethacrylate (PMMA), parylene, polyetheretherketone (PEEK), liquid-crystal polymer (LCP), kapton and mixtures thereof.

Preferably, the biocompatible polymer substrate is polyurethane or silicone. More preferably, the biocompatible polymer substrate is silicone.

It is appreciated that the polymer substrate comprises one or more opening(s) arranged on the two or more openings on one side of the wire(s) or cable(s).

That is to say, the opening(s) in the polymer substrate encompass(es) the partial openings of the electrical conductor. The opening(s) in the polymer substrate can be flush-fitted to the openings of the electrical conductor or the opening(s) in the polymer substrate can be broader in diameter than the partial openings of the electrical conductor. The later one has the advantage that the wire(s) or cable(s) within the electrical conductor can be better reached such that this embodiment is preferred.

If the at least one electrical conductor is in the form of bundle(s) or strand(s) of electrically insulated wire(s) or cable(s) and comprises an outer insulation, the opening(s) in the polymer substrate encompass(es) the partial opening(s) in the outer insulation of the one or more bundle(s) or strand(s) and the partial openings of the at least one electrical conductor.

In this embodiment, the opening(s) in the polymer substrate can be flush-fitted to the partial opening(s) in the outer insulation of the one or more bundle(s) or strand(s) or the partial opening(s) in the polymer substrate can be broader in diameter than the partial openings in the outer insulation of the one or more bundle(s) or strand(s). The later one has the advantage that the wire(s) or cable(s) within the electrical conductor can be better reached such that this embodiment is preferred.

In view of the above, it is appreciated that the wire(s) or cable(s) of electrically insulated wire(s) or cable(s) within the at least one electrical conductor is/are provided with free ends such that it may be directly connected to the at least one electrode, preferably by pressing such as pressing or swaging, such that a firmly-bonded connection is achieved. This embodiment is advantageous if one electrical conductor is assembled with multiple electrodes, such as multiple ring electrodes. That is to say, each electrical conductor comprises multiple partial openings in the electrical insulation and to each partial opening an electrode is connected.

Alternatively, the wire(s) or cable(s) within the one or more partial openings of the electrical conductor(s) are mechanically or laser cut. In this embodiment, one or both of the free ends of the cut wire(s) or cable(s) can be connected to the two or more electrodes.

It is appreciated that one or both of the free ends of the cut wire(s) or cable(s) is/are pressed or welded, preferably before connecting one or both of the free ends of the cut wire(s) or cable(s) to the two or more electrodes.

Preferably, the wire(s) or cable(s) within the two or more partial openings of the electrical conductor(s) are mechanically or laser cut.

According to another aspect of the present invention, a method for preparing an electrode-electrical conductor system for a medical device as defined herein is provided. The method comprises the steps of.

As regards the at least one electrical conductor, the at least two electrodes, and preferred embodiments thereof, it is referred to the comments provided above when discussing the electrode-electrical conductor system in more detail.

According to step b), the electrical insulation of the at least one electrical conductor is partially opened by laser ablation or mechanical cutting such as to obtain two or more partial openings on one side of the wire(s) or cable(s). Preferably, the electrical insulation of the at least one electrical conductor is partially opened by laser ablation such as to obtain two or more partial openings on one side of the wire(s) or cable(s).

It is appreciated that the laser ablation or mechanical cutting of the electrical insulation of the at least one electrical conductor results in two or more partial openings on one side of the wire(s) or cable(s). That is to say, the two or more partial openings are such that they are only partially surrounding the wire(s) or cable(s). It is appreciated that the partial opening of the electrical insulation increases the dielectric strength/resistance against electrical short circuits towards other insulated conductors within the electrode-electrical conductor system.

Laser ablation relates to a process of removing material from a solid surface by irradiating the surface with a laser beam. The material of the irradiated surface evaporates, sublimates, and/or is converted to a plasma. The laser ablation step may be carried out using a galvanometer scanner and/or a x-, y-, z- and rotation-axis for the positioning the laser on the surface of the monolithic substrate or the electrode, respectively. Laser ablation and the equipment therefor are known to the skilled person.

According to one embodiment, the laser ablating in step b) is carried out with a nanosecond laser or pulsed laser, more preferably with an ultrashort pulsed laser.

According to one embodiment of the present invention, the laser ablating is carried out with a laser pulse repetition rate of <NUM> to <NUM>, and preferably in the range of <NUM> to <NUM>, and/or a laser pulse duration of <NUM> fs to <NUM> ns, and preferably in the range of <NUM> to <NUM> fs, and/or a laser pulse energy in the range of <NUM> nJ to <NUM>µJ, and preferably <NUM> nJ to <NUM>µJ.

According to one preferred embodiment of the present invention, the laser ablating is carried out with a laser pulse repetition rate of <NUM> to <NUM>, and preferably in the range of <NUM> to <NUM>, and a laser pulse duration of <NUM> fs to <NUM> ns, and preferably in the range of <NUM> to <NUM> fs, and a laser pulse energy in the range of <NUM> nJ to <NUM>µJ, and preferably <NUM> nJ to <NUM>µJ.

It is appreciated that the two or more partial openings suitable for mechanically and electrically connecting the at least two electrodes to the at least one electrical conductor are added into the electrical insulation of the at least one electrical conductor where the at least two electrodes are to be connected to the wire(s) or cable(s) of the at least one electrical conductor.

Furthermore, the number of partial openings suitable for mechanically and electrically connecting the at least two electrodes to the at least one electrical conductor added into the electrical insulation of the at least one electrical conductor depends on the number of electrodes connected thereto. Preferably, the number of partial openings suitable for mechanically and electrically connecting the at least two electrodes to the at least one electrical conductor added into the electrical insulation of the at least one electrical conductor corresponds to the number of electrodes connected thereto.

It is further appreciated that the partial openings can be aligned with each other in order to specifically arrange the electrodes on the electrical conductor.

If such outer insulation is present, it is preferred that the outer electrical insulation of the at least one electrical conductor is circumferentially opened by laser ablation or mechanical cutting such as to obtain one or more opening(s) surrounding the at least one electrical conductor. Preferably, the outer electrical insulation of the at least one electrical conductor is circumferentially opened by laser ablation such as to obtain one or more opening(s) surrounding the at least one electrical conductor.

If such outer insulation is present, it is preferred that the outer insulation is ablated or cut circumferentially. This is advantageous as a pocket in the outer insulation is created, which receives the ring-electrode/electrode-segment after final diameter reduction by swaging, such that an isodiametric transition between electrode and outer coating is ensured.

According to step c) of the present method, the at least two electrodes are connected to the wire(s) or cable(s) via the two or more partial openings of the at least one electrical conductor by welding, pressing, swaging, adhesives, brazing, soldering and/or dimples, whereby a mechanical and electrical connection between the at least two electrodes to the at least one electrical conductor is achieved.

Preferably, the at least two electrodes are connected to the wire(s) or cable(s) via the two or more partial openings of the at least one electrical conductor by welding, pressing, swaging, adhesives, brazing, soldering and/or dimples, whereby a mechanical and electrical connection between them is formed in a firmly-bonded and/or force-locked manner. Preferably, the at least two electrodes are connected to the wire(s) or cable(s) via the two or more partial openings of the at least one electrical conductor by welding, pressing, swaging, adhesives, brazing, soldering and/or dimples, whereby a mechanical and electrical connection between them is formed in a firmly-bonded manner.

Preferably, the at least two electrodes are connected to the wire(s) or cable(s) via the two or more partial openings of the at least one electrical conductor by welding, e.g. laser welding.

Such methods are well known to the skilled person.

In one embodiment of the present method, the at least two electrodes are connected to the uncut wire(s) or cable(s) via the two or more partial openings of the at least one electrical conductor by welding, pressing, swaging, adhesives, brazing, soldering and/or dimples. Thus, the opening of the electrical insulation by laser ablation or mechanical cutting is preferably carried out such that the wire(s) or cable(s) are uncut.

In this embodiment, it is appreciated that the wire(s) or cable(s) within the electrical conductor is/are uncut in step b).

Thus, in a preferred embodiment, the method for preparing the electrode-electrical conductor system for a medical device comprises the steps of.

In another embodiment, the at least two electrodes are connected to one or both free ends of the cut wire(s) or cable(s) of the at least one electrical conductor. Preferably, the at least two electrodes are connected to both free ends of the cut wire(s) or cable(s) of the at least one electrical conductor.

In this case, the method comprises a further step of cutting the one or more wire(s) or cable(s) by laser cutting or mechanical cutting to obtain two free ends at the cut of the wire(s) or cable(s) before connecting the two or more electrodes to the two or more partial openings of the at least one electrical conductor. It is appreciated that this step is preferably carried out after step b).

In one embodiment, the partial opening of the electrical insulation of the at least one electrical conductor by laser ablation or mechanical cutting and the cutting of the one or more wire(s) or cable(s) by laser cutting or mechanical cutting can be carried out in the same step, i.e. by using the same machine/equipment.

It is to be noted that the step of cutting the one or more wire(s) or cable(s) by laser cutting or mechanical cutting to obtain two free ends at the cut of the wire(s) or cable(s) is carried out such that the remaining electrical insulation surrounding the wire(s) or cable(s) is/are uncut. i.e. the electrical insulation located on the electrical conductor opposite the partial openings in the electrical insulation of the at least one electrical conductor. Thus, it is appreciated that the at least one electrical conductor is only partially cut.

Additionally, the method may comprise a further step of lifting one or both of the free ends relative to the rest of the one or more wire(s) or cable(s) before attaching the two or more electrodes to the two or more partial openings of the at least one electrical conductor. Preferably, the method comprises a further step of lifting both free ends relative to the rest of the one or more wire(s) or cable(s) before attaching the two or more electrodes to the two or more partial openings of the at least one electrical conductor. It is appreciated that this step is only possible, if the one or more wire(s) or cable(s) of the electrical conductor is/are cut.

If the method comprises a step of cutting the one or more wire(s) or cable(s) by laser cutting or mechanical cutting to obtain two free ends at the cut of the wire(s) or cable(s), and optionally lifting one or both of the free ends relative to the rest of the one or more wire(s) or cable(s), the method may comprise a further step of pressing or welding one or both of the free ends, preferably both of the free ends. For example, the method comprises a further step of welding one or both of the free ends, preferably both of the free ends. Such a step is preferably carried out before connecting the two or more electrodes to the wire(s) or cable(s) via the two or more partial openings of the at least one electrical conductor by welding, pressing, swaging, adhesives, brazing, soldering and/or dimples in step c).

The at least one electrical conductor of step a) is partially or essentially completely covered with a polymer substrate such that the at least one electrical conductor is at least partially embedded in the polymer substrate.

It is preferred that the at least one electrical conductor is covered with the polymer substrate before step a) by well known methods. For example, the at least one electrical conductor is covered and molded or hot pressed (or laminated) with the polymer substrate.

In this case, step b) of the present method further comprises opening the polymer substrate in which the electrical conductor is embedded by laser ablation or mechanical cutting.

In one embodiment, the opening of the polymer substrate can be carried out by laser cutting or mechanical cutting. For this, the biocompatible substrate is preferably laser cut.

Preferably, the opening of the polymer substrate by laser cutting or mechanical cutting is carried out in the same step as the partial opening of the electrical insulation of the at least one electrical conductor by laser ablation or mechanical cutting and, if present, the cutting of the one or more wire(s) or cable(s), i.e. by using the same machine/equipment.

Alternatively, the method for preparing the electrode-electrical conductor system for a medical device comprises the steps of.

In step c), the two or more electrodes are connected to the wire(s) or cable(s) of step b) via the two or more partial openings in the electrical insulation of the at least one electrical conductor by welding, pressing, swaging, adhesives, brazing, soldering and/or dimples.

It is preferred to connect a ring electrode to the wire(s) or cable(s) of step b) via the two or more openings in the electrical insulation of the at least one electrical conductor, preferably via a bridge comprising a metal or a conductive polymer, e.g. the polymer substrate.

If the bridge comprises a metal, the bridge is preferably attached to the wire(s) or cable(s) of the electrical conductor by a first weld, and to the ring electrode by a second weld. Alternatively, such a bridge attached to the wire(s) or cable(s) of the electrical conductor by methods described in <CIT> or <CIT>.

In step c) of the method, the ring electrode(s) is/are positioned around the electrical conductor obtained in step b) at the position of the two or more partial openings. For this, two or more openings in the electrical insulation of the at least one electrical conductor may be aligned with each other. The positioning of the ring electrode(s) may be done by any suitable means known to the skilled person.

The ring electrode(s) may be attached to the wire(s) or cable(s) of the electrical conductor thereby selectively connecting the ring electrode(s) to the electrical conductor via the two or more partial openings in the electrical insulation of the at least one electrical conductor.

According to a preferred embodiment, the two or more electrodes are attached in step c) by swaging or welding, preferably by welding. According to another embodiment, the two or more electrodes are attached in step c) by swaging and welding.

The method according to the present invention may comprise additional process steps of capping one end of the electrical conductor, adding fixing or spacer elements to system, surface structuring of the two or more electrodes, and the like. Such processes are known to the skilled person and can be selected and adjusted according to the desired application of the electrode-electrical conductor system, preferably to the desired application in a medical device.

Claim 1:
An electrode-electrical conductor system for a medical device comprising
a) at least one electrical conductor comprising one or more electrically insulated wire(s) or cable(s) (<NUM>), wherein the electrical insulation (<NUM>) comprises two or more partial openings (<NUM>), which are arranged on one side of the wire(s) or cable(s), and
b) two or more electrodes, which are mechanically and electrically connected to the wire(s) or cable(s) (<NUM>) via the two or more partial openings (<NUM>) arranged on one side of the wire(s) or cable(s) (<NUM>) by welding, pressing, swaging, adhesives, brazing, soldering and/or dimples, and
characterised in that the electrical conductor is embedded in a polymer substrate, wherein the polymer substrate is a biocompatible polymer substrate (<NUM>), which is selected from the group comprising polyurethane, thermoplastic polyurethane (TPU), silicone, polyimide, phenyltrimethoxysilane (PTMS), polymethylmethacrylate (PMMA), parylene, polyetheretherketone (PEEK), liquid-crystal polymer (LCP), kapton and mixtures thereof, and comprises one or more opening(s) arranged on the two or more partial openings on one side of the wire(s) or cable(s).