Braid-supported spiral lead for implantable electrode leads - Patents.com

Abstract

The present invention relates to an implantable electrode lead 1 comprising at least one electrode pole 2, at least one conductor 3, 30 conductively connected to the at least one electrode pole 2, and at least one longitudinally extending electrical insulator 4, 40. According to the invention, the at least one conductor 3, 30 is spirally wound in a first rotational direction about a longitudinal axis x of the electrode lead 1, and the at least one electrical insulator 4, 40 is spirally wound in a second rotational direction about the longitudinal axis x, opposite to the first rotational direction.

Description

[Technical field]

[0001] The present invention relates to an implantable electrode lead. [Background technology]

[0002] Currently, implantable electrodes primarily use two different types of leads to the electrode: helical leads based on wire-like conductors, and relatively straight leads based on rope-like conductors.

[0003] Due to its plastic deformability, wires can be wound relatively easily into helical leads. However, precisely due to the plastic deformability of the wire, its pitch is limited to the smallest possible value, otherwise the fatigue strength is reduced. On the other hand, rope-like leads have a higher fatigue strength due to their small plastic deformability, but they cannot be wound into coils. However, it is also possible to form them into coils by supporting the rope-like leads in a dimensionally stable manner with additional electrical leads guided in a rotational direction opposite to that of the rope-like leads.

[0004] Particularly for electrode leads used to treat tachycardias, which require the delivery of high-voltage pulses for shock therapy, minimum lead spacing is important and must not be compromised to avoid flashover voltages between the leads. However, ensuring this minimum spacing with lead wires arranged in a crisscross pattern has proven to be very difficult. Summary of the Invention [Problem to be solved by the invention]

[0005] Based on the above, the problem to be solved by the present invention is to provide an improved implantable electrode lead with a spiral lead. [Means for solving the problem]

[0006] This problem is solved by an implantable electrode lead having the features of claim 1. Advantageous embodiments of the invention are set out in the corresponding dependent claims and are explained below.

[0007] According to claim 1, an implantable electrode lead is disclosed, the implantable electrode lead comprising: at least one electrode; at least one electrical conductor connected in a conductive manner to at least one electrode; at least one longitudinally extending electrical insulator; Here, according to the present invention, The at least one electrical conductor is helically wound in a first rotational direction about a longitudinal axis of the electrode lead, and the at least one electrical insulator is helically wound in a second rotational direction about the longitudinal axis opposite the first rotational direction.

[0008] Specifically, the rotational directions correspond to the types of helices (left-handed or right-handed) of the conductors and the electrical insulators, respectively. Specifically, a first rotational direction may mean that at least one conductor forms a left-handed helix. At least one electrical insulator forms a right-handed helix because it includes an opposite rotational direction. Similarly, if at least one conductor forms a right-handed helix, then at least one electrical insulator forms a left-handed helix. Thus, opposite rotational directions mean opposite handedness (left-handed helix and right-handed helix). This means that opposite rotational directions are understood with respect to the longitudinal axis of the implantable electrode from the proximal end to the distal end.

[0009] The structure formed by the conductors and insulators, particularly the braid, has the particular advantage of having an electrode lead that is robust and flexible while at the same time being capable of transmitting torque.

[0010] In other words, the present invention avoids the problems mentioned at the outset by designing a braided structure such that the conductive leads are each spirally wound in only one direction and are supported in their spiral form exclusively by insulation wound in the opposite direction.

[0011] Therefore, the minimum distance between the conductors can be achieved in a simplified manner by running the insulators parallel between the conductors without providing crossing points between the conductors. In other words, the conductors run parallel and do not cross each other. They are only crossed by the insulators. This avoids crossing of the conductors and at the same time establishes the braid.

[0012] In principle, this concept is not limited to electrode leads for treating tachycardia, but can also be applied to other electrode leads or catheters, particularly where cross-placed conductors are undesirable and a structure capable of transmitting torque is desired, e.g. to avoid subclavian crush syndrome.

[0013] In particular, the described method allows for a variable number of leads and can be used for catheters in electrophysiology where a large number of electrode leads are required in a very small space, where the concept of conventional leads with a single wire quickly reaches its limits when high-resolution mapping and differential temperature monitoring are to be performed simultaneously during ablation at many locations, for example to recognize linear lesions in a single procedure.

[0014] According to a preferred embodiment of the invention, the implantable electrode comprises an electrically insulating tube extending along said longitudinal axis. At least one electrical conductor and at least one electrical insulator are disposed on the tube (i.e., spirally wound in said opposite rotational directions on the tube). If the implantable electrode lead comprises multiple electrical conductors and multiple electrical insulators, these conductors and insulators are also disposed on the tube (i.e., spirally wound in the respective rotational directions on the tube).

[0015] According to one embodiment of the present invention, the electrical insulator is configured to be radially elastic. This embodiment provides a smaller overall diameter for the implantable lead. The insulator may be radially compressed at the crossing points with the conductors.

[0016] In accordance with a preferred embodiment of the present invention, the implantable electrode lead comprises a further electrical conductor spirally wound in a first rotational direction about the longitudinal axis.

[0017] Furthermore, in accordance with a preferred embodiment of the present invention, the further electrical conductor is conductively connected to a further electrode pole of the implantable electrode lead.

[0018] Additionally, in a preferred embodiment of the present invention, the implantable electrode lead includes additional electrical insulation spirally wound in a second rotational direction about the longitudinal axis.

[0019] Moreover, according to a preferred embodiment, the electrical conductors are spirally wound in a first rotational direction, while the crossing electrical insulators (e.g. filaments) are spirally wound in an opposite second rotational direction. In this way, the conductors are preferably fixed in place, but can run completely parallel without overlapping within the braid. In a further embodiment, the parallel running electrical conductors may further alternate with insulators. However, according to a preferred embodiment of the invention, in the braid formed by the electrical conductors and the electrical insulators, the conductors do not cross each other.

[0020] According to a preferred embodiment of the present invention, each electrode is a ring electrode.

[0021] Furthermore, according to a preferred embodiment of the present invention, each conductor is a rope comprising a plurality of strands, preferably a plurality of twisted or braided strands. Preferably, according to one embodiment, each strand comprises at least one wire (although it may comprise only a single wire). Furthermore, according to a preferred embodiment, each strand comprises a plurality of wires, in particular twisted wires.

[0022] Furthermore, according to a preferred embodiment of the present invention, each rope comprises 7 strands, preferably at least 7 strands, more preferably exactly 7 strands, and each strand comprises 7 twisted wires, in particular exactly 7 twisted wires.

[0023] Furthermore, in accordance with a preferred embodiment of the present invention, each rope comprises 19 strands, preferably at least 19 strands, more preferably exactly 19 strands, and each strand comprises one wire, in particular exactly one wire (i.e. a single wire).

[0024] According to yet another preferred embodiment of the invention, each rope comprises seven strands, preferably at least seven strands, more preferably exactly seven strands, each strand comprising one wire, in particular exactly one wire (i.e. a single wire).

[0025] Furthermore, in a preferred embodiment of the present invention, each wire comprises or is formed from a material selected from the list consisting of silver, an alloy containing nickel and cobalt, and MP35N.

[0026] Here, MP35N is an alloy containing approximately 35% by weight nickel, 35% by weight cobalt, 20% by weight chromium, and 10% by weight molybdenum.

[0027] According to a preferred embodiment of the invention, each wire comprises a core comprising a first metal and a sheath surrounding the core, the sheath being formed from a different second metal, In a preferred embodiment, the first metal is silver and the second metal is an alloy comprising nickel and cobalt, preferably MP35N (see above).

[0028] Further in accordance with a preferred embodiment of the present invention, each rope is covered with an electrically insulating armor, preferably in the form of an electrically insulating coating. In a preferred embodiment, the armor (specifically the coating) covering each rope is made of the following materials: ETFE (Ethylene Tetrafluoroethylene), PFA (Perfluoroalkoxy Polymer), Polyurethane (PU), Polyester Urethane (PEU), Polyether Urethane (PEEU), Polycarbonate Urethane (PCU), Silicone-based Polycarbonate Urethane (PCU), Polycarbonate Polyurea Urethane (PCHU), Polydimethylsiloxane Urethane (PSU), Polyisobutylene Urethane (PIU), Polyisobutylene-based Copolymers. (PIC), polyether block amide, PEBA, PEBAX, polyimide (PI), fluorinated hydrocarbons, ethylene tetrafluoroethylene copolymer (ETFE), polytetrafluoroethylene, polysulfone (PSU), polyethylene (PE), polypropylene (PP), polyamide (PA), silicone, polyimide (PI), fluorinated hydrocarbons, polytetrafluoroethylene (PTFE), tetrafluoroethylene (TFE), perfluoro(ethylene propylene) (FEP), PEEK.

[0029] Furthermore, in a preferred embodiment of the present invention, the implantable electrode lead comprises at least one electrical conductor and at least one electrical insulator, in particular an electrical insulation layer covering all the conductors and insulators of the braid.

[0030] Further in accordance with a preferred embodiment of the present invention, the implantable electrode lead is preferably configured to be screwed into human or animal tissue, preferably in the form of a septum, for sensing and / or stimulating in the vicinity of the left bundle branch (LBB), and the at least one helically wound electrical conductor and the at least one helically wound electrical insulator are configured to transmit torque when the implantable electrode lead is screwed into said tissue.

[0031] According to yet another preferred embodiment of the invention, each electrical insulator is formed as a plastic thread.

[0032] In the following, embodiments of the invention as well as further features and advantages will be briefly described with reference to the drawings. [Brief description of the drawings]

[0033] [Figure 1] 1 illustrates a portion of one embodiment of an implantable electrode lead according to the present invention. [Diagram 2] 1, but without the outer insulating tube and electrode poles, revealing the underlying conductors or insulators. [Diagram 3] 1 shows a portion of a further embodiment of an implantable electrode lead according to the present invention, without showing the outer electrical insulation layer covering the conductor and insulation; [Figure 4] 1 shows a cross-sectional view of a conductor in the form of a rope of one embodiment of an implantable electrode lead according to the present invention. [Diagram 5] 1 shows a cross-sectional view of a conductor in the form of a rope of one embodiment of an implantable electrode lead according to the present invention. [Figure 6] 1 shows a cross-sectional view of a conductor in the form of a rope of one embodiment of an implantable electrode lead according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] Figure 1 in conjunction with Figure 2 shows, for example, an embodiment of an implantable electrode lead 1 for the treatment of tachycardia according to the present invention, comprising at least one electrode pole 2 and at least one electrical conductor 3 conductively connected to the at least one electrode pole 2, and comprising at least one longitudinally extending electrical insulator 4. According to the present invention, the at least one electrical conductor 3 is helically wound in a first rotational direction about a longitudinal axis x of the electrode lead 1, and the at least one electrical insulator 4 is helically wound in a second rotational direction opposite to the first rotational direction about the longitudinal axis x.

[0035] The implantable electrode lead 1 may further comprise an insulating tube 5, e.g. made from silicone, having an inner diameter of e.g. 0.83 mm and an outer diameter of e.g. 1.13 mm. A coiled wire lead may be disposed in the inner lumen of the hose 5 (not shown), which may be connected to a helical fixation at the distal end. At least one conductor 3 and at least one insulator 4 are disposed on the hose 5.

[0036] Preferably, a plurality of conductors 3 and insulators 4 are provided, as will be described below with reference to Figures 1 and 2.

[0037] Preferably, at least two conductors 3 in the form of rope-like insulated electrical leads, each having a diameter of, for example, 0.36 mm, are wound in parallel on an insulating tube 5 together with two thread-like insulations 4', for example of polyurethane (PU), having a diameter of, for example, 0.15 mm or at least 0.15 mm, the two conductors 3 being braided in parallel in one rotational direction, in each case at least one PU thread 4' being located between the conductors 3, at least four PU threads being braided, for example, in the opposite rotational direction (in FIG. 2, as an example, six PU threads or insulations 4 are laid in the opposite rotational direction).

[0038] The electrical conductors 3 are, for example, a high impedance conductor 3 (e.g., MP3SN) that may in some cases be electrically connected to an electrode wire 1, specifically a ring electrode 2, that may be used to detect electrical activity, and a low impedance conductor 3, for example in the form of a DFT rope having a silver core, that is electrically connected to, for example, a shock coil (not shown).

[0039] An electrical insulating layer 6, in particular an insulating hose 6 (for example silicone or PU) having an inner diameter of at least 2.15 mm and an outer diameter of for example 2.5 mm, is preferably applied over the conductor 3 and the braid of the insulation 4, 4'. Furthermore, a PU hose can also be applied over the silicone hose.

[0040] For other types of tachycardia electrodes, for example electrodes with two shock coils or electrodes with two additional sensing electrodes (DX electrodes) in the atrium, the number of conductors 3 can be increased accordingly.

[0041] To simplify the contact of the braided conductor 3 with the outer electrode 2 or the shock coil, the conductor 3 can be provided with a suitable contact surface, for example in the form of a conductive tab, prior to the braiding process, which can be welded directly to the electrode 2. Thereby, subsequent stripping is unnecessary.

[0042] If the diameter of the conductive lead wire 3 is to be reduced without a corresponding increase in electrical resistance, then instead of one rope-like lead wire, two or more thinner rope-like lead wires can be braided in parallel in the same rotational direction and connected together to the electrode pole 2.

[0043] Instead of using filamentary insulating fibers 4 as part of the braid, insulating tubing can be used, which would result in less increase in the overall diameter of the electrode, but at the same time ensure that the elliptical deformation allows for increased spacing between the conductors 3.

[0044] 3 shows a further embodiment of an implantable lead 1 according to the invention, comprising a braid 9 of at least two conductors 3, 30 wound in parallel in a helical manner in a first rotational direction (e.g. on an electrically insulating carrier, e.g. a tube 5), in which at least two electrical insulators 4, 40 are wound in a helical manner in a second, opposite rotational direction (also in parallel). In other words, the conductors 3, 30 and the insulators 4, 40 have opposite handedness.

[0045] Preferably, the conductors 3, 30 used for the parallel running braids 9 are ropes and can be formed according to one of the embodiments shown in Figs. 4-6. In particular, conductive ropes are used for electrode leads, especially when low resistance is required. This is especially true for tachycardia electrodes, which have to transmit very high currents. The resistance of tachycardia electrodes is only 1-10 Ohms. A higher resistance would result in heating of the electrode during shock. Moreover, the voltage drop in the wire would be very large, so that the device would have to provide a rather high voltage.

[0046] For long-term implantation, copper, a metal with particularly low resistance, is excluded for biocompatibility reasons. Instead, silver is preferably used as the wire material, but due to its mechanical weakness, it is preferably supported by MP35N (35% nickel, 35% cobalt, 20% chromium, and 10% molybdenum), which is stable and corrosion-resistant. Mechanically stable wires made of MP35N may contain a silver core, which significantly reduces the conductivity. The wire can be wound in either a spiral due to the mechanical load at the electrode. Straight wires will break quickly in the electrode. Windings have the disadvantage of long lead lengths and therefore relatively high resistance. Alternatively, the wire 11 can be drawn very thin and many wires 11 can be combined into a rope. Such a rope is mechanically very stable against changes in bending load (even more stable than a spiral in some cases) and has a very low resistance, since the conductors can be connected by the shortest possible path.

[0047] According to the embodiment shown in Fig. 4, the rope 3, 3', 30 preferably used (for example in the embodiment of Figs. 1-3) is a 7 x 7 rope, i.e. seven wires 11, which may be made of the materials mentioned above, twisted into a strand 10. Seven such strands 10 are twisted in turn into the rope 3, 3', 30.

[0048] A little simpler is a 1×19 rope as shown in Fig. 5, where ropes 3, 3', 30 can be formed from 19 strands 10 each with a single wire 11. Such ropes can also be used for tachycardia and nerve electrodes.

[0049] Finally, FIG. 6 shows an embodiment of a rope 3 , 3 ′, 30 suitable for thin nerve electrodes, in which the rope comprises seven strands, each strand 10 being formed from a single wire 11 .

[0050] According to one embodiment, these ropes 3, 3', 30 are either made of solid MP35N wire, having a relatively high resistance sufficient for sensing and stimulation, or contain wires with a silver core, having a very low resistance. The silver content can vary, determining a compromise between low resistance and mechanical stability. Silver-cored wires are used in particular for tachycardia and neuroprobes. For neuroprobes, the silver core is less important for high energy, since these ropes need to be very thin and still conductive.

[0051] Preferably, each rope 3, 3', 30 shown in Figures 4 to 6 is preferably electrically insulated, i.e. surrounded by an electrically insulating sheath 7. This sheath 7 may be a coating material. The corresponding material of the sheath / coating material 7 is usually made of ETFE (Ethylene Tetrafluoroethylene) or PFA (Perfluoroalkoxy Polymer). Other sheathing / coating materials are also contemplated, namely polyurethane (PU), polyester urethane (PEU), polyether urethane (PEEU), polycarbonate urethane (PCU), silicone based polycarbonate urethane (PCU) which will bond better to silicone when extruded, polycarbonate polyurea urethane (PCHU), polydimethylsiloxane urethane (PSU), polyisobutylene urethane (PIU), polyisobutylene based copolymers (PIC), polyether block amides (PEBA, e.g. PEBAX), polyimides (PI), fluorinated hydrocarbons, ethylene tetrafluoroethylene copolymer (ETFE), polytetrafluoroethylene, polysulfone (PSU), polyethylene (PE), polypropylene (PP), polyamide (PA), silicone, polyimides (PI), fluorinated hydrocarbons, polytetrafluoroethylene (PTFE), tetrafluoroethylene (TFE), perfluoro(ethylene propylene) (FEP), PEEK.

[0052] Said electrical insulation by the sheath 7 makes it possible to prevent the formation of an electrolyte bridge between the conductors 3, 30 when body fluids enter.

[0053] The concept according to the invention is of particular use for tachycardia electrodes that are intended to be screwed into the septum to sense and stimulate close to the LBB (left bundle branch), unlike conventional tachycardia electrodes. Typically, electrodes that are actively fixed in tissue use a helix for fixation. The length of this helix is, for example, 2 mm. Longer helixes are also conceivable. However, if it is necessary to reach the LBB at a depth of, for example, 8 mm, the helix needs to be partially insulated so that the current is not unnecessarily dissipated (wasted) over its entire length during stimulation. It would be easier to keep the helix short and let the electrode body enter the septum along the helix until it reaches the LBB. Conventional helical electrodes are fixed by transmitting rotations at the connector pin through the inner conductor helix to the helix, and the helix extends from the helix body and is anchored in the tissue. This technique is useful for conventional electrode applications, as it prevents potential perforation of the cardiac tissue. The torque of the inner conductor is limited, so the helix can be very easily screwed into the tissue until the electrode head (housing) touches the tissue. In the case of normal RA or RV implantation, this is effective in preventing perforation, since if the free cardiac wall were to be perforated, the tip of the electrode would penetrate the pericardium, causing tamponade but no stimulation.

[0054] However, in this application, the septum will be intentionally penetrated by the electrode, preferably to reach the deep LBB. Torque transmission through the inner conductor (e.g., placed in the tube 5) is only moderately adequate, since so many rotations are required to penetrate the electrode. For this reason, in many cases, the threadable screw is omitted and a fixed screw is used, which grips the electrode lead 1 and rotates it by turning it. The braid 9 allows a higher torque to be applied than with the inner helix. However, it is also conceivable to use the connector pin to loosen the helix, preload the inner conductor by tightening the connector pin, and then implant by turning the electrode lead 1.

[0055] Tachycardia electrodes are typically constructed with multi-lumen tubing as the electrode body. Even with multi-lumen tubing, the soft tubing material (silicone or polyurethane) kinks easily and cannot transmit much torque.

[0056] However, the braid 9 of conductors 3, 30 and insulators 4, 40 arranged in opposite directions transmits torque very well. The disadvantage of the braid is that the filaments can cross each other. If the filaments consist of the current carrying conductor, there is a risk of compression of the insulation at the crossing points. Even if the conductors are not touching, there is a risk of insulation breakdown when a shock is applied, especially in tachycardia applications.

[0057] Thus, in this embodiment, the conductive ropes 3, 30 are guided in one rotational direction (chirality), while the crossing insulators 4, 40 (e.g. plastic filaments) are made of insulating material and are guided in the opposite rotational direction (opposite chirality). In this way, the conductors 3, 30 are fixed in place but run completely parallel without overlapping within the braid 9 (see, for example, FIG. 3). In a further embodiment, the parallel running conductors 3, 30 may further alternate with insulators. However, one of the advantageous features of this embodiment is that the conductors 3, 30 do not cross within the braid 9.

[0058] Furthermore, an electrical insulating layer 6 is preferably applied to the braid 9, for example to prevent direct exposure to blood (not shown in FIG. 3, so that the conductors 3, 30 / insulation 4, 40 are visible). The raw braided structure 9 would grow too far into the heart and blood vessels. This would make explantation of the electrode very difficult. A tube (e.g. polyurethane, silicone or copolymer) 6 can be used as the covering 6. In one embodiment, this tube 6 is very firmly connected to the braid 9. This has the advantage that the electrode lead 1 is particularly easy to grip and rotate in the hand. The torque applied by the fingers is directly transferred to the braid 9. This condition can be achieved by over-extending an insulating layer 6, for example made of polyurethane, copolymer or silicone.

[0059] According to a further embodiment, a reflow process can be used, in which a tube 6 made of thermoplastic material is pressed onto the braid 9 and shrinks in a thermal process, melting into the braided structure 9. The electrical conductors 3, 30 are routed continuously within the braid, which means, for example, that the conductor 3 of the ring electrode 2, which is connected to the ring electrode 2 (see FIG. 3) at the connection point 33, also runs under the shock coil (tachycardia electrode arranged in the form of a coil configured to deliver high voltage energy). This can lead to a short circuit when running.

[0060] According to one embodiment, the conductor 3 can be interrupted, for example by the size of one mesh, as shown in FIG. 3 showing the corresponding gap 12, so that this conductor 3 becomes electrically inactive below the shock coil, while the actual braid remains connected and its mechanical properties are hardly affected.

[0061] Preferably, plastic threads can be used as insulators 4, 40, which form the braid 9 with an opposite sense of rotation (chirality) to the conductors 3, 30. At the crossover points, the threads are very flattened due to the structure of the threads and the tension in the threads. The plastic threads used as insulators 4, 40 are configured to be radially elastic.

[0062] This has the significant advantage that only the cross-section of the conductors 3, 30 (e.g., the diameter of the cable, not the diameter of the filaments) is included in the intended wall thickness of the braid 9, so the inner and outer diameters can be kept small.

[0063] The present invention simplifies the manufacture of implantable electrode leads, is advantageously applicable to various types of electrode leads, avoids conductor crossing points, and thus increases safety against high voltage flashover, and also allows for an increased number of leads, while at the same time transmitting torque in an advantageous manner due to the braid formed from the crossing of electrical conductors and electrical insulators.

Claims

1. at least one electrode (2); at least one conductor (3, 30) electrically connected to the at least one electrode (2); and at least one longitudinally extending electrical insulator (4, 40), an embedded electrode lead (1), wherein the at least one conductor (3, 30) is spirally wound in a first rotational direction about the longitudinal axis (x) of the electrode lead (1), and the at least one electrical insulator (4, 40) is spirally wound in a second rotational direction opposite to the first rotational direction about the longitudinal axis (x). Embedded electrode lead (1).

2. The embedded electrode lead according to claim 1, further comprising a further conductor (30) spirally wound in the first rotational direction about the longitudinal axis (x).

3. The embedded electrode lead according to claim 2, wherein the further conductor (30) is electrically connected to a further electrode (2) of the embedded electrode lead (1).

4. The embedded electrode lead according to claim 1 or 2, further comprising a further electrical insulator (40) spirally wound in the second rotational direction about the longitudinal axis.

5. The embedded electrode lead according to claim 1 or 2, wherein each of the electrodes (2) is a ring electrode.

6. The embedded electrode lead according to claim 1, wherein each conductor (3, 3', 30) is a rope comprising a plurality of strands (10).

7. The embedded electrode lead according to claim 6, wherein each of the strands (10) comprises at least one wire (11).

8. The embedded electrode lead according to claim 6 or 7, wherein each said rope comprises 7 strands (10), and each said strand (10) comprises 7 twisted wires (11).

9. The embedded electrode lead according to claim 6 or 7, wherein each said rope comprises 19 strands (10), and each said strand (10) comprises 1 wire (11).

10. The embedded electrode lead according to claim 6 or 7, wherein each said rope comprises 7 strands (10), and each said strand (10) comprises 1 wire (11).

11. The embedded electrode lead according to claim 7, wherein each said wire comprises or is formed from a material selected from the list consisting of silver, an alloy containing nickel and cobalt, and MP35N.

12. The embedded electrode lead according to claim 7, wherein each said wire comprises a core comprising a first metal and a sheath surrounding said core, and said sheath is formed from a different second metal.

13. The embedded electrode lead according to claim 6, wherein each said rope is covered with an electrical insulation jacket (7).

14. The embedded electrode lead according to claim 1 or 2, wherein the embedded electrode lead comprises an electrical insulation layer (6) covering the at least one conductor (3, 3', 30) and the at least one electrical insulator (4, 40).

15. The implanted electrode lead (1) is configured to be screwed into human or animal tissue, and a braid (9) comprising at least one conductor (3, 30) wound in a spiral and at least one electrical insulator (4, 40) wound in a spiral is configured to transmit torque when screwing the implanted electrode lead (1) into the tissue. The implanted electrode lead according to claim 1 or 2.

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