Electrode arrangement for electrical stimulation and method for manufacturing an electrode arrangement

Description

[0001] The invention relates to an electrode arrangement for electrically stimulating the tissue of a living being, in particular for neurostimulation. Furthermore, the invention relates to a method for producing an electrode arrangement for electrically stimulating the tissue of a living being. An electrode body is also described.

[0002] Such electrode bodies and electrode assemblies generate an electric field in the region of the tissue of a living being for electrical stimulation of this tissue, with the electrodes being powered by an energy source. The terms electrode and electrode body are essentially synonymous, with the term electrode body being used hereinafter in particular to describe the design and structure of such electrodes of an electrode assembly.

[0003] EP 2 709 716 A1 discloses a device for implantation in or on a head, wherein the device has a housing in which several electrodes are arranged, the electrodes generating an electric field in a specific region of the head. The device is configured to receive and transmit data via Wi-Fi.

[0004] WO 2005 / 002665 A2 discloses an electrode system for implantation in a human, comprising two rows of electrodes, with several electrodes arranged side by side in a line within each row. The rows of electrodes can be controlled with different voltages, generating an electric field.

[0005] EP 2 038 004 B1 discloses an electrode system for implantation on the head outside the skull, comprising multiple disc electrodes arranged in a matrix. Depending on the application, selected disc electrodes can be controlled by a switching subsystem to generate a desired electric field without having to change the position of the disc electrodes. WO 2016 / 079263 A1, US 8 774 938 B2, and US 2017 / 252553 A1 disclose further electrode systems.

[0006] Based on this, it is an object of the present invention to provide an improved electrode assembly. Furthermore, it is an object of the present invention to provide an improved method for producing an electrode assembly.

[0007] The object is achieved by an electrode arrangement having the features of claim 1. Advantageous embodiments are described in the subclaims.

[0008] An electrode body of an electrode arrangement can be provided for electrically stimulating the tissue of a living being, in particular for neurostimulation. The electrode body is designed to be arranged at a location between the skull and scalp of a living being. The electrode body has a stimulation surface designed to be brought into contact with the tissue of the living being in order to generate electrical stimulation of the tissue by alternating current and / or direct current pulses. This also includes combined or superimposed alternating current and direct current pulses, for example, asymmetric pulses that do not have the same instantaneous or integral current flow in the positive and negative directions.

[0009] The electrode body can have a stimulation surface with an area of ​​at least 50 mm². The electric field generated by the electrode body of an electrode arrangement is attenuated by the skull of the living being. By generating a sufficiently strong electric field through a stimulation surface of the electrode body of at least 50 mm² without damaging the stimulation surface through electrochemical processes, this attenuation by the skull can be better compensated. Furthermore, the stimulation surface of at least 50 mm² proves advantageous when electrical pulses with a long pulse duration are used, since at a constant current strength they lead to lower current densities at the stimulation surface and thus reduce irreversible electrochemical processes. Furthermore, the potentially stimulable brain area is increased.The comparatively large stimulation surface also has a positive effect on the signal-to-noise ratio.

[0010] Alternatively or additionally, the electrode body can have a stimulation surface with an area of ​​at least 20 mm² and additionally a surface treatment that increases the effective stimulation surface. For example, such a surface treatment can create a rougher or dimpled surface, or even a fractal surface, resulting in an increase in surface area and reducing the transition impedance between the electrode body and the tissue, thus improving the signal-to-noise ratio.

[0011] Alternatively or additionally, the electrode body may have a fixation structure for fixing the electrode body to the tissue of a living being.

[0012] Alternatively or additionally, the electrode body may have a conductor connection via which the electrode body can be connected to an electrical conductor for electrically connecting the electrode body to an electrical device or another electrode body by soldering, gluing, welding or another connection technique.

[0013] Alternatively or additionally, the electrode body can be completely surrounded by an electrically insulating carrier material, except for the stimulation surface. This allows for easy arrangement and fixation of the electrode body in a higher-level structure, in particular an electrode array. Furthermore, the electrically insulating carrier material prevents or at least reduces the occurrence of leakage and short-circuit currents. In this case, the electrode body can also be surrounded by several electrically insulating carrier materials. For example, a polyimide substrate can be applied to the electrode body, which is additionally embedded in silicone.

[0014] Alternatively or additionally, the electrode body can have recesses distributed around its circumference for securing the electrode body in a carrier material. Such recesses have the advantage that the electrode body can be better secured in the carrier material by achieving an improved positive connection. During production, the initially liquid carrier material, such as silicone, enters the recesses of the electrode body. After the carrier material hardens, the electrode body is firmly bonded to the carrier material. The recesses can, for example, be arranged in a ring around a fastening opening in the electrode body and / or along the electrode edge.

[0015] In a particularly advantageous embodiment, the carrier material has a first, at least partially, circumferential sealing lip on an exposed contact side of the electrode body. A circumferential sealing lip has the advantage that the electrode body is protected from undesirable interactions with the environment at the implanted site, wherein the circumferential sealing lip provides insulation that remains intact even if the electrode body or an electrode arrangement receiving the electrode body is deformed. In contrast to electrode bodies and electrode arrangements known from the prior art, durability can be improved and short circuits caused by electrolytes or tissue located between the electrode and the skull can be prevented or at least significantly reduced. Furthermore, the signal-to-noise ratio is improved. It is conceivable that the first circumferential sealing lip can be formed in one piece from the carrier material.

[0016] It is advantageous if the first, at least partially circumferential, sealing lip extends beyond the electrode body by 0.05 mm to 1 mm, in particular 0.1 mm to 0.3 mm. These dimensions have been shown to ensure the flexibility of the electrode body and of an electrode assembly accommodating the electrode body, while simultaneously providing efficient insulation of the electrode body from external influences. The sealing lip can extend beyond the electrode body in any spatial direction. For example, the sealing lip can extend beyond the electrode body in the normal direction of the stimulation surface and / or centripetally to the stimulation surface.

[0017] According to an advantageous embodiment, the electrode body is circular, elliptical, ring-shaped, or bean-shaped. Such a shape ensures good contact of the electrode body with the tissue of the living being.

[0018] It is advantageous if the conductor connection of the electrode body is designed as a tangential conductor connection. A tangential conductor connection runs orthogonally to the connecting line between the contact point and the center of the electrode body. A conductor connected to the electrode body via the conductor connection touches the electrode body like a tangent. This has the advantage that the connection point is relieved of mechanical stress on the electrical conductor, such as a tensile force, thus reducing the likelihood of damage to the connection point and thus electrode failure. The electrical conductor can be welded or soldered to the electrode body, for example.

[0019] However, it is also conceivable for the conductor connection of the electrode body to be designed as a rectangular conductor connection. A rectangular conductor connection is understood to be a conductor connection that perpendicularly intersects the contour or circumferential line of the electrode body in the connection area, so that a right angle is formed between the conductor and the contour or circumferential line in the connection area. In contrast to the tangential conductor connection, the rectangular conductor connection runs parallel to, rather than orthogonally to, the connecting line between the contact point and the center of the electrode body. This conductor connection form is advantageous, for example, with polyimide substrates.

[0020] In an advantageous embodiment, an electrical conductor for electrically connecting the electrode body to an electrical device or another electrode body is connected to the conductor connection.

[0021] It is advantageous if the electrical conductor runs in a meandering pattern. A meandering arrangement reduces the stress on the electrical conductor, particularly in its connection area, which can arise, for example, from bending and pulling an electrode assembly that accommodates the electrode body. Arranging the conductor on a curved path further improves stress relief. The curved path advantageously runs around the primary electrode over an angular range of 40° to 100°, based on a 360° system.

[0022] According to a favorable embodiment, the connection point between the electrical conductor and the electrode body is sealed, in particular with an epoxy resin. This has the advantage of protecting the sensitive connection point from external influences such as liquids that would lead to electrode failure, for example, due to corrosion.

[0023] In an advantageous embodiment, the electrical conductor consists of a material or material composition that, in ion-containing solution, does not form a local electrochemical element with the material of the electrode body. Such a material selection reduces the likelihood of corrosive processes that could lead to damage to the electrode or the electrical conductor.

[0024] Advantageously, the electrode body or at least the stimulation surface consists entirely or partially of a biocompatible and inert material such as platinum-iridium, which, inherently or through a special coating, for example with iridium oxide or graphene, has a high charge injection capacity.

[0025] It is advantageous if the fixing structure of the electrode body comprises an insulating sleeve designed to insulate a mechanical fastening element from the electrode body. The insulating sleeve thus electrically insulates a mechanical fastening element, such as a screw, so that no unwanted electrical currents are generated from the electrode body to the fastening element.

[0026] The fixation structure of the electrode body may comprise fixation means on the circumference or one end of the electrode body or may comprise fixation means embedded in the carrier material next to or adjacent to the electrode body in order to connect the electrode body to the tissue of a living being.

[0027] In a favorable embodiment, the fixation structure has at least one fastening opening in the electrode body, through which the electrode body can be fastened to the tissue of the living being by means of the mechanical fastening element, e.g. a screw, a nail, a staple, a thread or a similar mechanical fastening element. Furthermore, it is particularly advantageous if the aforementioned insulating sleeve is arranged in the fastening opening. The electrode body can then be fastened, for example, to a bone structure of the living being via the fastening opening by guiding a mechanical fastening element, such as a screw, through the fastening opening, particularly advantageously through an insulating sleeve arranged in the fastening opening, and fixing it to the bone structure. However, other fastening means such as surgical threads for fastening the electrode body are also conceivable.In this case, the fastening opening, and advantageously also an insulating sleeve arranged in the fastening opening, are designed to allow attachment of the alternative fastening means. For example, in the case of the surgical thread, the insulating sleeve has at least two openings.

[0028] According to an advantageous embodiment, the insulating sleeve has a second, at least partially circumferential sealing lip. This has the advantage of protecting the electrode body from liquids that may reach the electrode body through gaps between the electrode body or the electrode assembly accommodating the electrode body and the insulating sleeve. It is conceivable that the insulating sleeve or the second circumferential sealing lip can be formed in one piece from the carrier material.

[0029] It is advantageous if the insulating sleeve is made at least partially of polyetheretherketone (PEEK). Polyetheretherketone is a high-temperature-resistant thermoplastic, which is also used in medical technology. Polyetheretherketone has the advantage of being biocompatible and radiolucent. Furthermore, the material has a low coefficient of friction, so only a small amount of force can be transferred from a fastening device such as a screw to the insulating sleeve and thus to the electrode body, thus protecting it from damage such as deformation. Polyetheretherketone also has an electrically insulating effect, preventing unwanted electrical currents from flowing between the electrode body and the mechanical fastening device.

[0030] According to an advantageous embodiment, the electrode body has a preformed, concave stimulation surface. Such a stimulation surface can optimally adapt to the external shape of most cranial regions of a living being. The electrode body is thus better adapted to the curvature of the bone structure.

[0031] Alternatively, the electrode body may have a preformed flat stimulation surface with at least one incision and / or cutout, which improves the flexible adaptability of the electrode body to the outer contour of the skull of a living being.

[0032] It is advantageous if the electrode body is also suitable for recording the living being's bioelectrical signals. For example, an electroencephalogram (EEG), electrocardiogram (ECG), or electromyogram (EMG) can be recorded using the electrode body. For this purpose, an amplifier with an analog-to-digital converter (ADC) and, if necessary, an analog or digital signal filter can be connected to or integrated into the electrode body. These can be used for diagnostic purposes or to control the stimulation following the recording of the living being's bioelectrical signals. For this purpose, an evaluation and control unit can also be connected to the electrode body or integrated into a power source that can be connected to the electrode body.

[0033] In an advantageous embodiment, the electrode body has a maximum surface area of ​​7.1 cm², in particular a maximum surface area of ​​4.6 cm². Such a comparatively small electrode body enables good integration and reduced interference with the tissue of the living being, thus reducing the risk of tissue damage.

[0034] According to an advantageous embodiment, the electrode body has a maximum thickness of 2 mm, in particular a maximum thickness of 1 mm. In this way, an arrangement formed with one or more electrode bodies can also have a small thickness, for example less than 3 mm, less than 2 mm or less than 1 mm. In this way, an implanted electrode arrangement hardly protrudes under the scalp of the living being. This has a cosmetic advantage, whereby the environment cannot perceive the implanted electrode arrangement. In addition, the likelihood of damage from external influences is reduced, since the potential surface area for such damage is reduced. Wearing comfort for the living being is also improved by a reduced thickness.

[0035] Thus, an electrode arrangement for electrically stimulating tissue of a living being, in particular an electrode arrangement for neurostimulation, is provided, comprising at least one primary electrode and at least one secondary electrode. One, several, or all primary electrodes are each formed by an electrode body, and / or one, several, or all secondary electrodes are each formed by an electrode body.

[0036] The at least one primary electrode and the at least one secondary electrode are each connected to a connecting element by means of electrical conductors, wherein the connecting element is configured for connection to another electrode or an energy source. Alternatively or additionally, the primary electrode and the secondary electrode are arranged on a common carrier material.

[0037] The electrodes of the electrode arrangement are connected to a connecting element, which can be connected to an energy source and / or an electrical signal source to supply the electrodes with current. The electrical signal source can be configured to transmit electrical stimulation signals. The electrodes can be embedded in the carrier material. The connecting element can have a plug connector or be designed as a plug connector. However, it is also conceivable for the connecting element to be designed as a polyetheretherketone adapter, which represents the transition between the electrode arrangement and the energy source or the electrical signal source.The energy source and / or the signal source can be implanted at a different position in the body of the living being than the electrode arrangement, wherein the energy source can be connected to the connection element by means of an electrical conductor and this electrical conductor can be welded or soldered to the connection element.

[0038] Furthermore, an electrode arrangement for electrically stimulating tissue of a living being is provided, in particular for neurostimulation, wherein the electrode arrangement is configured to be arranged at a location between the skull and the scalp of a living being. The electrode arrangement has at least one primary electrode and at least one secondary electrode. It also has a stimulation surface configured to be brought into contact with the tissue of the living being in order to generate electrical stimulation of the tissue by means of alternating current and / or direct current pulses. This also includes combined or superimposed alternating current and direct current pulses, for example asymmetric pulses that do not have the same instantaneous or integral current flow in the positive and negative directions.

[0039] The electrode arrangement according to the invention can be designed to be implanted between the scalp and skull of the subject. Especially in the field of neurostimulation for epilepsy patients for whom medication treatment is ineffective, a maximally invasive method involving the implantation of an intracranial electrode system has often been used to provide relief to the patient. The electrode arrangement according to the invention can be implanted on the subject's skull bone to achieve the necessary stimulation of specific brain regions, which represents a significantly less invasive procedure for the patient and thus means less stress for the patient.

[0040] The electrode arrangement can have a total stimulation surface area of ​​the primary electrodes and / or a total stimulation surface area of ​​all secondary electrodes with a surface area of ​​at least 50 mm². The electric field generated by the electrode arrangement is attenuated by the skull of the living being. By generating a sufficiently strong electric field through a stimulation surface of the electrode arrangement of at least 50 mm² without damaging the stimulation surface through electrochemical processes, this attenuation by the skull can be better compensated. Furthermore, the stimulation surface of at least 50 mm² proves advantageous when electrical pulses with a long pulse duration are used, since they lead to lower current densities at the stimulation surface at a constant current strength, thus also reducing irreversible electrochemical processes.Furthermore, the potentially stimulable brain area is increased. The comparatively large stimulation surface also has a positive effect on the signal-to-noise ratio. The electrode area is limited by the overall size of the electrode array, ensuring that the electrode array can still be implanted in humans.

[0041] Alternatively or additionally, the electrode arrangement can have a total stimulation surface area of ​​the primary electrodes and / or a total stimulation surface area of ​​all secondary electrodes with a surface area of ​​at least 20 mm² and additionally a surface treatment that increases the effective stimulation surface area. For example, such a surface treatment can create a rougher or dimpled surface or even a fractal surface, resulting in a surface enlargement and reducing the transition impedance between the electrode body and tissue, thus improving the signal-to-noise ratio.

[0042] Alternatively or additionally, the electrode arrangement has a fixation structure for fixing the electrode arrangement to the tissue of a living being.

[0043] Alternatively or additionally, the electrode array is completely surrounded by an electrically insulating carrier material, except for the stimulation surfaces of the primary and secondary electrodes. This allows for easy positioning and fixation of the electrode array on the tissue of the organism. Furthermore, the electrically insulating carrier material prevents or at least reduces the occurrence of leakage and short-circuit currents at the electrodes. The electrode array can also be surrounded by several electrically insulating carrier materials. For example, a polyimide substrate can be applied to the primary and / or secondary electrodes, which can also be embedded in silicone.

[0044] In an advantageous embodiment of the electrode arrangement, a reinforcing element, in particular a reinforcing mesh, is arranged on the carrier material. Such a reinforcing element can increase the tear strength of the electrode arrangement. This has the advantage that the geometric accuracy of the electrode arrangement, i.e. the position of the primary electrode and the secondary electrodes relative to one another, and thus the necessary electric field, can be ensured. Advantageously, the reinforcing element is a reinforcing mesh, such as a surgical mesh, the strands of which extend between the primary electrode and the secondary electrodes. It is possible for certain parts of the electrode arrangement not to have a reinforcing element. For example, it is conceivable for no such reinforcing element to be arranged on the contacting section of the electrode arrangement in order not to reduce its flexibility.

[0045] According to an advantageous embodiment of the electrode arrangement, at least one electrical conductor is at least partially surrounded by the carrier material. This has the advantage that the electrical conductor is held in position by the carrier material. This prevents unwanted displacement of the electrical conductor. Furthermore, the electrical conductor is insulated against external influences, shielding it from liquids, for example, and thus preventing unwanted reactions.

[0046] It is advantageous if the thickness of the electrode array is less than 4 mm, especially less than 2 mm. This ensures that an implanted electrode array barely protrudes beneath the scalp of the subject. This has a cosmetic advantage, as the implanted electrode array cannot be detected by the environment. Furthermore, the likelihood of damage from external influences is reduced, as the potential area for such damage is reduced. A reduced thickness also improves wearing comfort for the subject.

[0047] According to an advantageous embodiment, the electrode arrangement has at least one primary electrode and at least two secondary electrodes. It is particularly advantageous if the electrode arrangement has at least four secondary electrodes. A larger number of electrodes allows for more precise control of the electric field configuration, which can be advantageous, for example, due to inhomogeneities in the conductivity of the tissue or for more precise focusing of the electric field on a tissue area. Furthermore, with multiple electrodes, it is possible to choose between multiple channels of signal derivation, which increases the information content. It is advantageous if the electrode arrangement has between three and eight secondary electrodes, in particular exactly four secondary electrodes.

[0048] It is advantageous if at least one of the electrical conductors of the secondary electrodes is arranged in a meandering pattern around the primary electrode, with the meandering arrangement of the electrical conductor running along a curved path around the primary electrode. A meandering arrangement reduces the mechanical stress on the electrical conductors, particularly their connection areas, which can arise, for example, from bending and pulling the electrode arrangement. The arrangement on a curved path further improves stress relief. The curved path advantageously runs around the primary electrode over an angular range of 40° to 100°, based on a 360° system.

[0049] In principle, the carrier material of the electrode array can have fastening structures with which the electrode array can be attached to a bone structure of the living being. The fastening structures can be designed, for example, as screw holes or eyelets for creating a suture connection.

[0050] Alternatively or in combination, the primary electrode and / or at least one of the secondary electrodes each have at least one fastening opening, with an insulating sleeve arranged in each of the fastening openings. The electrode arrangement can then be fastened to a tissue structure of the living being via the fastening opening by fastening means such as screws being guided through the insulating sleeves arranged in the fastening openings and fixed to the tissue structure. However, other fastening means such as surgical threads for attaching the electrodes are also conceivable. In this case, the insulating sleeve is designed in such a way that the alternative fastening means can be attached, in the case of the surgical thread, for example, through at least two openings in the insulating sleeve.By securing the primary electrode and / or the secondary electrodes, the remaining electrodes can be held in a desired position and improved contact with the cranial bone can be achieved, allowing the desired electrical field to be generated at the desired location even during the implantation of the electrode array. This type of attachment also reduces unwanted tissue ingrowth between the electrode and the cranial bone. Furthermore, the insulating sleeve electrically insulates the attachment device, preventing unwanted electrical currents from flowing from the primary electrode and / or the secondary electrodes to the attachment device.

[0051] The insulating sleeve can be made at least partially of polyetheretherketone (PEEK). Polyetheretherketone is a high-temperature-resistant thermoplastic, which is also used in medical technology. Polyetheretherketone has the advantage of being biocompatible and radiolucent. Furthermore, the material has a low coefficient of friction, allowing only minimal force to be transferred from the screw to the insulating sleeve and thus to the respective electrode, thus protecting it from damage such as deformation. Polyetheretherketone also acts as an electrical insulator, preventing unwanted electrical currents from flowing between the electrodes and the screw.

[0052] The insulating sleeve of the electrode assembly can have a second sealing lip that extends at least partially around the entire circumference. This has the advantage of protecting the electrodes from fluids that may reach the electrodes through gaps between the electrode assembly and the insulating sleeve. It is conceivable that the insulating sleeve or the second sealing lip could be formed in one piece from the carrier material.

[0053] Alternatively or in combination, the primary electrode and / or at least one of the secondary electrodes have recesses distributed over the circumference for fixing in the carrier material. Such recesses have the advantage that the primary electrode and the secondary electrodes can be better fixed in the carrier material by achieving an improved positive connection. During production, the initially liquid carrier material, such as a silicone, enters the recesses of the primary electrode and the secondary electrodes, and after the carrier material has hardened, the primary electrode and the secondary electrodes are firmly connected to the carrier material. The recesses can, for example, be arranged in a ring around the fastening opening of the primary electrode and / or at least one of the secondary electrodes and / or along the electrode edge of the primary electrode and / or at least one of the secondary electrodes.

[0054] Alternatively, or in combination, a connection point between the electrical conductor and the primary electrode and / or at least one of the secondary electrodes is a tangential conductor connection. A tangential conductor connection runs orthogonally to the connecting line between the contact point and the center of the respective electrode. The conductor touches the electrode like a tangent. This has the advantage that the connection point is relieved when the electrical conductor is subjected to stress, such as a tensile force, thus reducing the likelihood of damage to the connection point and thus of failure of the respective electrode. The electrical conductor can, for example, be welded or soldered to the electrode.

[0055] However, it is also conceivable for a connection point between the electrical conductor and the primary electrode and / or at least one of the secondary electrodes to be formed as a rectangular conductor connection. A rectangular conductor connection is understood to be a conductor connection that perpendicularly intersects the contour or circumferential line of the electrode in the connection area, so that a right angle is formed between the conductor and the contour or circumferential line in the connection area. Compared to the tangential conductor connection, the rectangular conductor connection runs parallel rather than orthogonally to the connecting line between the contact point and the center of the electrode. This conductor connection form is advantageous, for example, with polyimide substrates.

[0056] In a favorable embodiment, the electrode arrangement has a contacting section, wherein the connecting element is arranged on the contacting section and wherein the contacting section protrudes laterally from the electrode arrangement. The protruding contacting section allows the connecting element to be mechanically insulated from the area of ​​the primary electrode and the secondary electrode, thus preventing undesirable interactions.

[0057] Furthermore, it is advantageous if the contacting section has a greater length than width. The length is the dimension in the direction of travel of the contacting section, while the width is the dimension perpendicular to the direction of travel of the contacting section. The elongated design allows forces acting on the contacting section to be dissipated, preventing these forces from reaching the area of ​​the electrodes and causing damage there.

[0058] Furthermore, it is advantageous if fastening elements for screw fastening are arranged on the contacting section. The fastening elements can be designed, for example, as elongated holes, whereby the contacting section can be fastened to the living being by means of screws or other fastening means. In this way, a secure attachment of the contacting section to the living being can be achieved, whereby mechanical forces can be dissipated via the skull. The fastening elements can be arranged in such a way that they form a hexavalent bearing, whereby the rotational and translational degrees of freedom are limited.

[0059] According to a favorable embodiment, the total area of ​​the secondary electrodes is larger than the area of ​​the primary electrode. This embodiment enables good current distribution across the tissue surface of the living being and a reduced risk of tissue damage. Furthermore, it is advantageous if the primary electrode and / or the secondary electrodes each have an area of ​​50 mm² to 71 mm², in particular an area of ​​20 mm² to 46 mm². With these electrode surfaces, particularly good current distribution is achieved with a reduced risk of tissue damage.

[0060] Alternatively, in an advantageous embodiment, the total area of ​​the secondary electrodes can also be smaller than the area of ​​the primary electrode. This design allows for a reversed stimulation current direction, such as anodal stimulation instead of cathodal stimulation, without leading to corrosion-related damage to the electrodes. This allows for the treatment of various indications and clinical pictures.

[0061] It is advantageous if the secondary electrodes are arranged on at least one circular path around the primary electrode. In a further advantageous embodiment, the secondary electrodes of the electrode arrangement can be arranged equidistantly on at least one circular path around the primary electrode. Furthermore, it is advantageous if the secondary electrodes are distributed on a concentric circular path around the primary electrode. This distribution of the secondary electrodes around the primary electrode further promotes the generation of an electric field through a shield such as a skullcap.

[0062] According to a favorable embodiment, the center point of at least one of the secondary electrodes is arranged at a distance of 5 mm to 55 mm, in particular at a distance of 10 mm to 50 mm, from the center point of the primary electrode. Furthermore, it is advantageous if the edge of at least one of the secondary electrodes is arranged at a distance of 1 mm to 8 mm, in particular at a distance of 2 mm to 6 mm, from the edge of the primary electrode. It has been shown that small distances between the secondary electrodes and the primary electrode enable optimal focusing of the electric field, whereby a sufficient distance between the secondary electrodes and the primary electrode can reduce or prevent the likelihood of leakage and short-circuit currents and increase the depth of penetration of the electric field into the head. These distances therefore form an optimized middle ground between the opposing requirements of focusing and leakage and short-circuit current prevention.Short-circuit currents. A greater distance between the electrodes leads to a higher signal, but also to lower focality.

[0063] Advantageously, the carrier material has at least one recess, wherein the recess is arranged between adjacent secondary electrodes. It is also conceivable for the carrier material to have a tapered section, i.e. a decreasing or lower material thickness. In this way, the electrode arrangement can be designed to be flexible. The recess or tapered section increases flexibility, particularly at the secondary electrodes, wherein a recess or tapered section is advantageously arranged between each two adjacent secondary electrodes. The increased flexibility thus makes it possible to respond to the irregular surface of the skullcap of a living being by ensuring that the electrode arrangement has sufficient contact with the skullcap at every position.

[0064] It is proposed that the carrier material have a first, at least partially, circumferential sealing lip on an exposed contact side of the primary electrode and / or on at least one of the secondary electrodes. A circumferential sealing lip has the advantage that the electrodes are protected from undesired interactions with the environment at the implanted site, wherein the circumferential sealing lip provides insulation that remains intact even if the electrode arrangement is deformed. In contrast to electrode arrangements known from the prior art, durability can be improved and short circuits caused by electrolytes or tissue located between the electrode and the skull can be prevented or at least significantly reduced. Furthermore, the signal-to-noise ratio is improved. It is conceivable that the first circumferential sealing lip can be formed in one piece from the carrier material.

[0065] According to an advantageous embodiment, a first at least partially circumferential sealing lip projects at least partially beyond one, several or all primary electrodes and / or at least partially beyond one, several or all secondary electrodes by 0.05 mm to 1 mm, in particular 0.1 mm to 0.3 mm. It has been shown that these dimensions ensure the flexibility of the electrode arrangement and, at the same time, provide efficient insulation of the electrodes from external influences. The sealing lip can project beyond the electrode body of the respective electrode in any spatial direction. For example, the sealing lip can project beyond the electrode body in the normal direction of the stimulation surface and / or centripetally to the stimulation surface.

[0066] Any insulation described in this application, for example by the carrier material or sealing lips, also contributes to improved signal quality of the electrodes, so that the signal-to-noise ratio is improved.

[0067] The connection point of the electrical conductor with the primary electrode and / or at least one of the secondary electrodes can be sealed, in particular with an epoxy resin or other sealant. This has the advantage of protecting the sensitive connection point from external influences such as liquids that would lead to failure, for example, due to corrosion, of the respective electrode.

[0068] Advantageously, the electrical conductor is made of a material that, when in electrical contact with the electrode material, does not form a local electrochemical element in aqueous electrolyte solution. This material selection reduces the likelihood of corrosive processes that could lead to damage to the electrodes or the electrical conductor.

[0069] The problem is further solved by a method having the features of claim 13.

[0070] Thus, a method for producing an electrode arrangement for electrically stimulating tissue of a living being is provided, in particular for producing an electrode arrangement according to the features described above.

[0071] In a process step a), electrode bodies are produced from a film of an electrode material of suitable thickness, e.g. by laser cutting or punching. In a process step b), if appropriate, a surface coating and / or a surface structuring is applied to at least part of the electrode surface. In a process step c), an electrical conductor is attached to each electrode body or the electrical conductor is produced from a single piece together with the electrodes. In a process step d), if appropriate, an epoxy resin or another electrical insulator is applied to the connection point. In a process step e), a mold of the electrode arrangement is produced from the carrier material. In a process step f), the electrode body and, if appropriate, the electrical conductor and, if appropriate, the reinforcing element are embedded.In a process step g), an electrical conductor is connected to the contacting section of the electrode arrangement.

[0072] The problem is further solved by a method having the features of claim 14.

[0073] Thus, a method for producing an electrode arrangement for electrically stimulating tissue of a living being is provided, in particular for producing an electrode arrangement according to the features described above.

[0074] In process step a), a carrier material is provided. In process step b), one or more electrode bodies are produced on the carrier material by a vapor deposition process and / or by electroplating. In process step c), a surface coating and / or surface structuring is optionally applied to at least part of the electrode surface. In process step d), the carrier material is optionally embedded in another insulating carrier material.

[0075] In an advantageous embodiment of the method, at least one electrical conductor for electrically connecting the electrode body to an electrical device or another electrode body is produced by a vapor deposition process and / or by galvanic deposition and connected to the electrode body.

[0076] The invention is explained in more detail below by way of example with the accompanying drawings. They show: Figure 1 - a schematic structure of an electrode body; Figure 2 - a schematic representation of an electrode body with a connected electrical conductor and an insulating sleeve; Figure 3 - a schematic representation of the electrode body from Figure 2with a carrier material; Figure 4 - a schematic representation of several electrode bodies which are connected to an energy source via electrical conductors; Figure 5 - a schematic representation of an electrode body embedded in a carrier material in a side view; Figure 6 - a schematic representation of an electrode arrangement in a plan view; Figure 7 - a schematic representation of an electrode arrangement with electrodes embedded in a carrier material in a side view; Figure 8 - a schematic representation of a method for producing an electrode arrangement; Figure 9 - a schematic representation of a further method for producing an electrode arrangement.

[0077] Figure 1shows a schematic structure of an electrode body 20. The electrode body 20 shown is designed as a round electrode. However, other electrode shapes are also conceivable. It is clear that the electrode body 20 has a fastening opening 10 for attachment to a living being. It is also clear that the electrode body 20 has recesses 16 distributed over its circumference. The recesses 16 enable improved fixation of the electrode body 20 in a Figure 3 shown carrier material 6. In the manufacture of a carrier material accommodating the electrode body 20, for example in Figure 6 In the electrode arrangement 1 shown, the carrier material 6 is initially in a liquid state, wherein the carrier material 6 is distributed in the recesses 16 and the electrode body 20 can thus be held fixed after the carrier material 6 has hardened.

[0078] Figure 2schematically shows an electrode body 20, also designed as a round electrode, with a connected electrical conductor 4. For connecting the electrical conductor 4, a conductor connection 7 is provided on the electrode body 20, which can be designed, for example, as a projection protruding from the circular surface of the round electrode in order not to reduce the effective stimulation surface of the electrode body 20. The conductor connection 7 is designed here as a tangential conductor connection 7, so that the connected electrical conductor 4 touches the electrode body 20 like a tangent. This relieves the connection point in the event of a tensile force occurring, thus preventing damage to the conductor connection 7 and resulting failure of the electrode.The electrical conductor 4 can be soldered or welded to the conductor terminal 7 of the electrode body 20. It is advantageous if the connection point is sealed against external influences, for example, with an epoxy resin. It can be seen that the electrical conductor 4 runs in a meandering shape. This reduces the stress on the electrical conductor 4, particularly in its connection area at the conductor terminal 7, which can arise, for example, from bending and pulling of an electrode assembly 1 that accommodates the electrode body.

[0079] Furthermore, it can be seen that the electrode body 20 has a fastening opening 10 into which an insulating sleeve 11 is inserted. This allows the electrode body 20 to be fastened to a skull of the living being via a fastening element, for example a screw, through the insulating sleeve 11. The insulating sleeve 11 prevents excessive torque from being transmitted to the electrode body 20 and thus damaging it. Furthermore, an undesired current flow between the electrode body 20 and the fastening element is avoided. The insulating sleeve 11 can be made of a polyetheretherketone, for example. By fastening the electrode body 20 via a fastening opening 10, an exact position of the electrode body 20 can be ensured, which can generate a desired electric field in the target region.

[0080] In Figure 3 the electrode body 20 is made of Figure 2shown. In this view, it can be seen that the electrode body 20 is embedded in a carrier material 6 indicated by hatching. The carrier material 6 is electrically insulating and completely surrounds the electrode body 20 except for the stimulation surface. The carrier material 6 can consist of silicone, for example. However, other materials are also conceivable that fulfill the application-specific properties (biocompatibility, flexibility, electrically insulating, etc.). The carrier material 6 enables simple arrangement and fixation of the electrode body 20 in a higher-level structure, in particular an electrode arrangement 1. In addition, the electrically insulating carrier material 6 prevents or at least reduces the occurrence of leakage and short-circuit currents.

[0081] Furthermore, the electrode body 20 has recesses 16. The carrier material 6, which is initially liquid during a manufacturing process, penetrates into the recesses 16 and thus, after curing, supports the fixation of the electrode body 20 in the carrier material 6.

[0082] Figure 4 schematically shows several, namely a total of four, electrode bodies 20, which are connected to an energy source 21 via electrical conductors 4. The energy source 21 can be designed as a supply source to supply the electrode bodies with electrical current and thereby enable their operation. Alternatively or additionally, the energy source 21 can be designed as a signal source to generate targeted electrical stimulation signals at the electrodes.

[0083] It can be seen that the electrode bodies 20 do not have to be directly connected to the energy source 21. An arrangement is also conceivable in which one electrode body 20 is connected to another electrode body 20, which in turn is connected to the energy source 21. For this purpose, the respective electrical conductor 4 runs either between one electrode body 20 and the energy source 21 or between two electrode bodies 20. By indirectly connecting an electrode body 20 to the energy source 21 via another electrode body 20, tissue regions further away from the energy source 21 can also be reached without having to provide longer electrical conductors 4 or stretching them and thereby exposing them to a greater risk of stress. Of course, several, i.e. more than two, electrode bodies 20 can also be connected to another electrode body 20.The multiple conductors 4 can, for example, be soldered side by side to the conductor terminal 7 provided for connecting the electrical conductors 4. In principle, it is of course also conceivable to use a longer conductor 4 for the spatially more distant electrode body 20 and to electrically connect another, spatially closer electrode body 20 as a branch.

[0084] Figure 5shows a side view of the electrode body 20 embedded in a carrier material 6. It can be seen that the electrode body 20 has a continuous fastening opening 10, wherein an insulating sleeve 11 is arranged in the fastening opening 10, and wherein the electrode body 20 can be fastened to a bone or other tissue structure of the living being via the insulating sleeve 11 by means of a fastening element (not shown). It is clear that the carrier material 6 has a first circumferential sealing lip 14 on a contact side 15 of the electrode body 20. The circumferential sealing lip 14 can be formed integrally from the same material as the carrier material 6. In this way, the electrode body 20 can be fastened to the site to be implanted despite unevenness, without causing deformation of the electrode body 20.It is also conceivable for the circumferential sealing lip 14 to partially project beyond the electrode body 20, thereby enabling improved fixation of the electrode body 20 in the carrier material 6. It can also be seen that the electrode body 20 is exposed on the contacting side 15 and is covered in an insulating manner by the carrier material 6 on the other side. The electrode body 20 is thus embedded in the carrier material 6. This enables efficient insulation of the electrode body 20 from the outside and at the same time ensures the generation of a desired electric field in a body region towards the contacting side 15. It is also conceivable for the insulating sleeve 11 to have a second circumferential sealing lip (not shown), which further promotes this effect.

[0085] Figure 6shows a schematic representation of an electrode arrangement 1 in a plan view. For clarity, the electrode arrangement 1 is partially cut away, whereby different layers of the electrode arrangement 1 can be seen. The electrode arrangement 1 has a primary electrode 2, wherein the primary electrode 2 is surrounded by four secondary electrodes 3. The secondary electrodes 3 are arranged on a common circular path around the primary electrode 2. The primary electrode 2 and the secondary electrodes 3 are each connected via an electrical conductor 4 to a connection element 5, wherein the connection element 5 is configured for connection to an energy source 21. The primary and secondary electrodes 2, 3 can advantageously have further features of the previously described electrode body 20.

[0086] It is clear that the components (primary electrode 2, secondary electrodes 3, electrical conductors 4 and connection element 5) are arranged on a carrier material 6. The carrier material 6 can be made of silicone, for example. However, other materials that meet the application-specific properties (biocompatibility, flexibility, electrical insulation, etc.) are also conceivable. It is clear that the primary electrode 2 and the secondary electrodes 3 as well as the electrical conductors 4 are embedded in the carrier material 6. It is also clear that the electrical conductors 4 of the rear secondary electrodes 3, which are further away from the connection element 5, are arranged in a meandering pattern around the primary electrode 1, with the meandering arrangement running on a curved path around the primary electrode 2. In this way, the load on the electrical conductors 4 and thus also the probability of failure of the secondary electrodes 3 can be reduced.The electrical conductors 4 are connected to the secondary electrodes 3 via a connection point, wherein the connection point is a tangential conductor connection 7. The electrical conductor 4 can be soldered or welded to the secondary electrode 3, whereby it is advantageous if the connection point is sealed against external influences, for example, with an epoxy resin.

[0087] A reinforcing element 8 in the form of a surgical mesh is arranged on the electrode assembly 1, with the reinforcing element 8 being inserted between the outer layers of the carrier material. The reinforcing element 8 is arranged between the primary electrode 2 and the secondary electrodes 3 to improve the tear resistance.

[0088] It can be seen that the connection element 5 is arranged on a contacting section 9, wherein the contacting section 9 protrudes laterally from the electrode arrangement 1 and has a greater length L than width B. The elongated design of the contacting section 9 has the advantage that the connection element 5 is decoupled from the primary electrode 2 and the secondary electrodes 3, wherein forces acting on the contacting section 9 are compensated over the length L of the contacting section 9 to such an extent that these forces are not transmitted at all or are transmitted only weakly to the electrode arrangement 1. To ensure the flexibility of the contacting section 9, it can be advantageous if the reinforcing element 8 is not arranged on the contacting section 9 and extends only to the transition area to the contacting section 9 or extends gradually into the contacting section 9, similar to a kink protection element.

[0089] The electrode arrangement 1 is designed to be implanted, for example, between the scalp and skull of a living being. The primary electrode 2 and the secondary electrodes 3 have fastening openings 10, with an insulating sleeve 11 inserted into each fastening opening 10. The electrode arrangement 1 can then be fastened to the skull of the living being using fastening elements such as screws through the insulating sleeve 11. The insulating sleeve 11 prevents excessive torque from being transmitted to the primary electrode 2 or the secondary electrode 3, which could damage them. Furthermore, an undesired current flow between the electrodes (primary electrode 2 and secondary electrodes 3) and the fastening element is avoided. The insulating sleeve 11 can be made of a polyetheretherketone, for example.By attaching the electrode assembly 1 to the respective electrodes (primary electrode 2 and secondary electrode 3) via fastening openings 10, a precise position of the electrodes can be ensured, which can generate a desired electric field in the target region. Furthermore, it can be seen that two fastening elements 12 for screwing onto a living being are arranged on the contact section 9. The contact section 9 can be attached to the skull of the living being using the fastening elements 12.

[0090] It is clear that the electrode arrangement 1 has a recess 13 between each secondary electrode 3. The recesses 13 increase the flexibility of the electrode arrangement 1, particularly in the area of ​​the secondary electrodes 3. Since the bone of a living being is generally not flat, but the electrodes (primary electrode 2 and secondary electrodes 3) must be positioned precisely on the bone, it is advantageous if the flexibility of the electrode arrangement 1 is correspondingly high so that the electrodes 2, 3 can be attached in appropriate proximity to the bone and the electrode arrangement 1 can adapt well to the shape of the bone.

[0091] Figure 7shows a schematic representation of a primary electrode 2 and a secondary electrode 3 in the carrier material 6 in a side view. It can be seen that the primary electrode 2 and the secondary electrode 3 each have a through-hole 10, wherein an insulating sleeve 11 is arranged in the hole 10, and wherein the electrode arrangement 1 can be attached to a bone or tissue structure of a living being by means of fastening elements via the insulating sleeve 11.

[0092] It is clear that the carrier material 6 has a first circumferential sealing lip 14 on the exposed contacting side 15 of the secondary electrodes 3. The circumferential sealing lip 14 can be formed integrally from the same material as the carrier material 6. In this way, the electrode arrangement 1 can be attached to the site to be implanted despite unevenness, without causing deformation of the secondary electrodes 3. It is also conceivable for the circumferential sealing lip 14 to partially project beyond the secondary electrode 3, thus enabling improved fixation of the secondary electrode 3 in the carrier material 6. It can also be seen that the secondary electrodes 3 are exposed on the contacting side 15 and are covered in an insulating manner by the carrier material 6 on the other side. The secondary electrodes 3 are thus embedded in the carrier material 6.This enables efficient insulation of the secondary electrodes 3 from the outside and simultaneously ensures the generation of a desired electric field in a body region toward the contact side 15. It is also conceivable for the insulating sleeve 11 to have a second circumferential sealing lip 17, which further promotes this effect. It is advantageous if all electrodes of the electrode arrangement 1 have this configuration.

[0093] Figure 8 shows schematically a method for producing an electrode arrangement for electrically stimulating tissue of a living being, in particular for producing an electrode arrangement 1 according to the features described above.

[0094] In a process step a), electrode bodies 20 are produced from a film of an electrode material of suitable thickness, e.g. by punching or cutting, e.g. with a laser. In an optional process step b), a surface coating and / or a structuring of the surface is applied to at least part of the electrode surface. In a process step c), an electrical conductor 4 is attached to each electrode body 20. In an optional process step d), an epoxy resin or another electrical insulator is applied to the connection point. In a process step e), a mold of the electrode arrangement 1 is cast from the carrier material 6. In a process step f), the electrode body 20 and optionally the electrical conductor 40 and optionally the reinforcing element 8 are embedded.In a method step g), an electrical conductor 4 is connected to the contacting section 9 of the electrode arrangement 1.

[0095] Figure 9 schematically shows a further method for producing an electrode arrangement 1 for electrically stimulating tissue of a living being, in particular for producing an electrode arrangement 1 according to the features described above. In a method step a), a carrier material 6 is provided. In a method step b), one or more electrode bodies 20 are produced on the carrier material 6 by a vapor deposition process and / or by galvanic deposition. In an optional method step c), a surface coating and / or structuring of a surface is applied to at least part of the electrode surface. In an optional method step d), the carrier material 6 is embedded in a further insulating carrier material.

[0096] The figures are intended to represent one possible embodiment. Other forms of the teachings of the invention are also conceivable. Furthermore, the embodiments of the embodiment are not inextricably linked to one another, so that, for example, the implementation of the invention is not dependent on the specifically described embodiments of the embodiment. Thus, variability, for example, in the number or positioning of the individual elements such as the primary electrode 2, secondary electrodes 3, cutouts 13, and / or recesses 16, is always conceivable.

Claims

1. Electrode arrangement (1) for the electrical stimulation of tissue of a living being, in particular electrode arrangement (1) for neurostimulation, having at least one primary electrode (2) and at least one secondary electrode (3), one, several or all primary electrodes (2) each being formed by an electrode body (20) and / or one, several or all secondary electrodes (3) each being formed by an electrode body (20), wherein the primary electrode (2) and the secondary electrode (3) are arranged on a common carrier material (6), characterized in that the carrier material (6) has a first at least partially circumferential sealing lip (14) on an exposed contacting side (15) of the electrode body (20), which at least partially projects beyond one, several or all primary electrodes (2) and / or at least partially beyond one, several or all secondary electrodes by 0.05 mm to 1 mm, in particular 0.1 mm to 0.3 mm.

2. Electrode arrangement (1) according to claim 1, characterized in that the electrode arrangement (1) is adapted to be placed at a location between the skull and the scalp of a living being, and wherein the electrode arrangement (1) comprises a stimulation surface adapted to be brought into contact with the tissue of the living being in order to generate electrical stimulation of the tissue by alternating current and / or direct current pulses, wherein the electrode arrangement (1) comprises one or more of the following features a) to d): a) a total size of the stimulation surface of the primary electrodes (2) and / or a total size of the stimulation surface of all secondary electrodes (3) with an area of at least 50 mm2, b) a total size of the stimulation surface of the primary electrodes (2) and / or a total size of the stimulation surface of all secondary electrodes (3) with a surface area of at least 20 mm2 and additionally a surface treatment increasing the effective stimulation surface, c) a fixing structure for fixing the electrode arrangement (1) to the tissue of a living being, d) the electrode arrangement (1) is completely surrounded by an electrically insulating carrier material (6) except for the stimulation surfaces of the primary and secondary electrodes.

3. Electrode arrangement (1) according to claim 1 or 2, characterized in that a reinforcing element (8), in particular a reinforcing mesh, is arranged on the carrier material (6).

4. Electrode arrangement (1) according to one of claims 1 to 3, characterized in that the at least one electrical conductor (4) is at least partially surrounded by the carrier material (6).

5. Electrode arrangement (1) according to one of claims 1 to 4, characterized in that the thickness of the electrode arrangement (1) is less than 3 mm, in particular less than 2 mm or less than 1 mm.

6. Electrode arrangement (1) according to one of claims 1 to 5, characterized in that the electrode arrangement (1) has at least one primary electrode (2) and at least two secondary electrodes (3).

7. Electrode arrangement (1) according to one of claims 1 to 6, characterized in that at least one of the electrical conductors (4) of the secondary electrodes (3) is arranged in a meandering manner around the primary electrode (2), the meandering arrangement of the electrical conductor (4) running along a curved path around the primary electrode (2).

8. Electrode arrangement (1) according to one of claims 1 to 7, characterized in that the electrode arrangement (1) has a contacting section (9), wherein the connecting element (5) is arranged on the contacting section (9) and wherein the contacting section (9) projects laterally from the electrode arrangement (1).

9. Electrode arrangement (1) according to claim 8, characterized in that the contacting section (9) has a greater length than width.

10. Electrode arrangement (1) according to one of claims 1 to 9, characterized in that the secondary electrodes (3) are arranged on at least one circular path around the primary electrode (2).

11. Electrode arrangement (1) according to one of claims 1 to 10, characterized in that the edge of at least one of the secondary electrodes (3) is arranged at a distance of 1 mm to 8 mm, in particular at a distance of 2 mm to 6 mm, from the edge of the primary electrode (2).

12. Electrode arrangement (1) according to one of claims 1 to 11, characterized in that a first at least partially circumferential sealing lip (14) at least partially projects beyond one, several or all primary electrodes (2) and / or at least partially beyond one, several or all secondary electrodes by 0.05 mm to 1 mm, in particular 0.1 mm to 0.3 mm.

13. Method for producing an electrode arrangement (1) for the electrical stimulation of tissue of a living being according to one of the preceding claims, characterized by the following steps: a) Manufacture of electrode bodies (20), in particular by laser cutting, from a sheet of an electrode material of suitable thickness, b) If necessary, application of a surface coating and / or structuring of the surface on at least part of the electrode surface, c) Attachment or manufacture of one electrical conductor (4) to each electrode body (20), d) If necessary, apply an epoxy resin to the joint, e) Casting a mold of the electrode assembly (1) from the carrier material (6), f) Embedding the electrode bodies (20) and, if applicable, the electrical conductors (4) and, if applicable, the reinforcing element (8), g) Connecting an electrical conductor (4) to the contacting section (9) of the electrode arrangement (1).

14. Method for producing an electrode arrangement (1) for electrical stimulation of tissue of a living being according to one of the preceding claims, characterized by the following steps: a) Providing a carrier material (6), b) Producing one or more electrode bodies (20) on the carrier material (6) by a vapor deposition process and / or by electrodeposition, c) If necessary, application of a surface coating and / or structuring of the surface on at least part of the electrode surface, d) If necessary, embed the carrier material (6) in another insulating carrier material.