Implantable medical lead and manufacturing method therefor

Abstract

The invention refers to an electrode assembly for an implantable medical lead that allows cost-effective manufacturing. The electrode assembly comprises - a lead body section with a plurality of electrically conducting wires and / or electrically conducting wire bundles and an electrically insulating outer layer forming an outer surface, and - an electrode member fixed to the outer surface of the lead body section, wherein the electrode member comprises at least one cutting edge shearing and penetrating through the electrically insulating outer layer of the lead body section and / or shearing and penetrating through an electrically insulating sheathing of a single electrically conducting wire or through an electrically insulating sheathing of a single electrically conducting wire bundle thereby interlocking with and providing an electrical connection of the electrode member to the single electrically conducting wire (33, 133) or the single electrically conducting wire bundle at the cutting edge. The invention further refers to an implantable medical lead comprising such electrode assembly (30, 130, 230) and a manufacturing method for such implantable medical lead.

Description

[0001] Applicant: BIOTRONIK SE & Co. KG

[0002] Date: 24.09.2025

[0003] Our Reference: 24.051P-WO

[0004] Implantable Medical Lead and Manufacturing Method therefor

[0005] The invention generally relates to an implantable medical lead for electrical therapy like defibrillation, pacing, spinal cord stimulation, deep brain stimulation or neurostimulation or for electrical sensing of bodily parameters, as well as to an electrode assembly for such implantable medical lead and to a respective manufacturing method.

[0006] Medical leads implanted in a patient’s body for electrical cardioversion or pacing of the heart are generally known in the art. In particular, electrically conducting leads may be implanted in or about the heart to reverse (i.e., defibrillate or cardiovert) certain life-threatening arrhythmias or to stimulate contraction (pacing) of the heart. Electrical energy is transmitted from a pulse generator which can be electrically connected to the lead. Such transmitted electrical energy is applied to the heart via the lead to return the heart to normal rhythm or to stimulate the heart. Leads have also been used to sense conditions, materials or events (generally referred to as "sense" or "sensing") in the body, such as electrical potential in the atrium or ventricle of the heart. For that such medical lead may be connected to a sensing device using a connector assembly at the proximal end of the medical lead. Alternatively, the sensed signals may be transmitted to and processed by the pulse generator, and, for example, used for pacing control. Further, implantable medical leads may be used in connection with spinal cord stimulation (SCS), deep brain stimulation (DBS) or neurostimulation devices.

[0007] Implantable medical leads represent the electrical link between the stimulation signal generator or processing unit for measured signals and the patient’s body tissue which is to be treated or sensed. Accordingly, the medical lead must be mechanically and electrically reliably connected to the patient’s body tissue at a pre-defined target location. During implantation alternating mechanical loads are expected, when the medical lead is pushed through a typically curved catheter.

[0008] In the aforementioned use cases for implantable medical leads, electrodes are used to either transmit stimulation signals to the patient's body tissue or to receive bodily signals. These implantable medical leads usually have multiple electrical conducting wires comprising a conductive core and, if applicable, individual electrically insulating sheathing extending within a lead body. The lead body electrically and mechanically connects each electrode to an input of a stimulation signal generator or of a processing unit by an electrical connector located at the proximal end of the lead body. In many cases, the medical lead comprises a plurality of electrically conducting wires and / or wire bundles to provide the required therapy and sensing functionality. The single or bundled conducting wires in most cases having electrically insulating sheathing and located within the lead body, are arranged as a bundle, which is susceptible to damage from varying mechanical loads, particularly bending. To reduce mechanical stress caused by varying loads the wires or wire bundles are braided or arranged in a helical structure, wherein the helical structure is also used for high voltage applications. Examples for structures of implantable medical leads are provided in documents US 3,760,812 A and EP 3 756 725 Al.

[0009] Each single conducting wire or wire bundle can be, among other techniques, electrically connected to an electrode member fixed to the outer surface of the medical lead via crimping and welding. However, this method of providing an electrical connection to an electrode member is cost intensive and challenging for leads with braided or helical structure. This is because a separate component is needed and a stripping step of the electrically insulating material is necessary to facilitate a reliable electrical connection to the crimping sleeve. When stripping single conducting wires or wire bundles they split open, which makes it difficult to install a crimping sleeve. A direct connection of a wire, e.g. by laser welding to an electrode member, is also made more difficult by splitting. Additionally, for some material pairings, providing a reliable direct electrical connection to the electrode member by direct welding is difficult, e.g. with regard to the frequently used nickel cobalt alloy MP35N Drawn Filled Tubing (DFT) wires (sil ver-filled). Additionally, leads with a high number of single wires or wire bundles, wherein a plurality thereof comprises an electrically insulating sheathing are hard to handle.

[0010] Accordingly, it is an objective of the present invention to provide a cost-effective implantable medical lead suitable for various use cases as well as a cost-effective electrode assembly of such lead. Accordingly, it is an objective to propose a respective, automatable manufacturing process for such lead.

[0011] The above-mentioned objective is solved by an electrode assembly having the features of claim 1 and by an implantable medical lead having the features of claim 13. Accordingly, the objective is solved by a manufacturing method having the features of any one of claims 14 and 15.

[0012] The object is solved by an electrode assembly for an implantable medical lead comprising

[0013] - a lead body section with a plurality of electrically conducting wires and / or electrically conducting wire bundles and an electrically insulating outer layer forming an outer surface, and

[0014] 24.05 IP- WO / 24.09.2025 - an electrode member fixed to the outer surface of the lead body section, wherein the electrode member comprises at least one cutting edge shearing and penetrating through the electrically insulating outer layer of the lead body section and / or shearing and penetrating through an electrically insulating sheathing of a single electrically conducting wire or through a single electrically insulating sheathing of one electrically conducting wire bundle thereby interlocking with and providing an electrical connection of the electrode member to the single electrically conducting wire or the single electrically conducting wire bundle at the cutting edge.

[0015] The lead body of the implantable medical lead extends from the proximal end of the implantable medical lead to its distal end along an axial direction. At a section, e.g. towards the distal end or the proximal end, one electrode assembly providing an electrode for sensing and / or therapy and / or for providing an electrical connection to an electrical connector assembly or two or more than two of such electrode assemblies is / are located.

[0016] The implantable medical lead may be used in connection with electrical therapy like defibrillation, pacing, SCS, DBS, neurostimulation and / or in connection with electrical sensing of bodily parameters. For that, the electrical connector assembly may be electrically and mechanically detachably connected with a pulse generator and / or a sensing and / or data processing device. Electrical signals from the pulse generator and / or the sensing and / or data processing device may be transmitted via the lead to the electrode and / or sensed electrical signals from the electrode may be transmitted via the lead to the pulse generator and / or the sensing and / or data processing device, wherein the electrode is formed by the electrode member.

[0017] The lead body has a structure consisting of an electrically insulating material accommodating a plurality of electrically conducting wires and / or electrically conducting wire bundles. The lead body may comprise a tubular electrically insulating member and an inner lumen accommodating the plurality of electrically conducting wires and / or wire bundles, wherein each electrically conducting wire or wire bundle comprises an individual electrically insulating sheathing. Alternatively, the plurality of electrically conducting wires and / or wire bundles with or without electrically insulating sheathing may be embedded in electrically insulating matrix material, wherein the wire / wire bundles and the electrically insulating material together forms the lead body. The electrically conducting wire bundle may be formed, for example, by at least two braided or wound electrically conducting strands. For example, the electrical insulation forming by an insulating sheathing of one wire or one wire bundle fully surrounds an electrically conducting core to provide an individual electrical insulation with regard to each other wire or wire bundle. The plurality of wires or wire bundles with or without individual electrically insulating sheathing may form, for example, a braided structure or a helical

[0018] 24.05 IP- WO / 24.09.2025 structure wound around a core wire. Electrically insulating filaments may be intertwined into the above-mentioned wire structure to separate the electrically conducting wires / wire bundles effecting an electrical insulation and spatial separation. Each wire of the plurality of electrically conducting wires and / or each wire bundle of the plurality of wire bundles extends from the proximal end of the lead body to its distal end. With regard to all above-mentioned embodiments, the lead body comprises an electrically insulating outer layer (provided, e.g., by a tubular member or a matrix material) fully encompassing all wires / wire bundles and forming an outer surface. To electrically connect an electrode member fixed to the outer surface of the electrically insulating outer layer of the lead body section, one wire / wire bundle is electrically connected to this electrode member through the electrically insulating outer layer and, if applicable, additionally through an individual electrically insulating sheathing provided at said wire / wire bundle. The lead body may comprise a circular or rectangular cross section. The lead body section forms a section of the lead body and is located, for example, at a distal end section of the lead body or at a proximal end section of the lead body.

[0019] The electrode assembly comprises the electrode member which is fixed to the outer surface of the lead body section and provides the electrical connection to a pre-defined single wire or single wire bundle of the plurality of wires and / or wire bundles.

[0020] The electrode member of the electrode assembly comprises at least one cutting edge which is configured to shear and penetrate to the electrically insulating material of the lead body section concerned, e.g., the electrically insulating outer layer and / or, if applicable, the electrically insulating sheathing of a single electrically conducting wire or a single electrically conducting wire bundle. Additionally, the at least one cutting edge is configured to interlock with the single electrically conducting wire or the single electrically conducting wire bundle thereby effecting the electrical connection to the electrode member. The electrode member having the at least one cutting edge allows a cost-effective manufacturing process by automatically stripping the electrically insulating outer layer of the lead body section and / or the electrically insulating sheathing of the single electrically conducting wire or the electrically insulating sheathing of the single electrically conducting wire bundle and / or providing the electrical connection to the electrode member thereby omitting separate stripping and splitting for connection with a crimping sleeve. The at least one cutting edge may extend at least sectionwise parallel to the axial direction of the lead body section. Alternatively or additionally, the at least one cutting edge may extend in radial direction of the lead body section. The at least one cutting edge may comprise or consist of a sharp peak and / or may comprise and consist of an elongated sharp blade. By the at least one cutting edge, the at least one electrode member is reliably and permanently electrically connected to the single electrically conducting wire or to the single electrically conducting wire bundle.

[0021] 24.05 IP- WO / 24.09.2025 The electrode member may enclose the entire or a partial circumference of the lead body section concerned. The electrode member may comprise an additional fixing element to attach the electrode member reliably and permanently to the outer surface of the lead body section. The electrode assembly may comprise one electrode member, two electrode members or more than two electrode members, wherein each electrode member is electrically connected to a different single wire or single wire bundle. In case the electrode assembly comprises two or more than two electrode members, they are arranged at a distance along the axial direction of the lead body.

[0022] A surface of the electrode member facing away from the lead body section provides a pre-defined function such as an electrode function and / or a sensor function transmitting electrical signals or may carry an additional functional element such as an actuator or another electrically conducting element having a pre-defined shape. Such additional functional element may be permanently attached to the electrode member by crimping or welding.

[0023] In one embodiment of the electrode assembly, the electrode member is a first sleeve exhibiting at least one groove on its inner surface, wherein the at least one groove extends in an axial direction of the first sleeve and forms at least one cutting edge. The at least one groove extends along the inner surface of the first sleeve. The inner surface is formed by a through-hole of the first sleeve extending in a substantially axial direction of the first sleeve and having, for example, a substantially circular cross section or another cross section adapted to the cross section of the lead body section. The at least one cutting edge is formed by one rim (edge) or both rims (edges) of the at least one groove, wherein one rim is located at a transition of the inner surface of the through-hole to the groove if the circumferential direction is considered. At least part of the rim forms a sharp cutting edge, wherein the cutting edge extends substantially in the axial direction and may by at least sectionwise straight or curved. This embodiment is, for example, used in case one single conductive wire / wire bundle with electrically insulated sheathing is pulled out of the lead body. The lead body is introduced into the through hole of the first sleeve and the first sleeve and the lead body perform a relative movement in axial direction of the lead body for mounting. Thereby, the at least one groove receives a portion of the electrically insulating sheathing of the single electrically conducting wire / wire bundle. Subsequently, the at least one cutting edge of the groove shears and penetrates through the electrically insulating sheathing of the single electrically conducting wire / wire bundle, i.e. strips the electrically insulating sheathing and interlocks with the single wire / wire bundle. Accordingly, a reliable and permanent electrical connection of the electrically conducting wire / wire bundle and the electrode member via the at least one cutting edge is formed.

[0024] 24.05 IP- WO / 24.09.2025 The outer shape of the first sleeve may be, for example, cuboid or cylindrical. An outer surface section of the first sleeve, which is configured to be in contact with human tissue, may be, e.g., flat or curved, for example, may be shaped like a shell surface of a cylinder. Further, the first sleeve may be a single-piece element or may consist of a first element and a second coaxially arranged and initially separated element, wherein both elements are fixedly attached to each other during manufacturing of the electrode assembly for the implantable medical lead. Both elements may be fixed, for example, by crimping, by a clip-on joint or by welding.

[0025] In one embodiment, a plurality of grooves is provided on the inner surface of the first sleeve. These grooves may be, for example, evenly spaced at the circumference of the inner surface. The first sleeve exhibits, e.g., a number of grooves between one and eight on its inner surface. For example, the width or diameter of one groove varies between 0.1 mm and 0.5 mm and the depth of one groove varies between 0.05 mm and 0.2 mm. The width and / or depth of the at least one groove is adapted to the diameter of the single wire or single wire bundle to be automatically stripped, i.e. is formed little smaller than this diameter. One groove may have, for example, a cross section forming a segment of a circle. The outer diameter of the first sleeve, may be, for example, between 1.5 mm and 4.0 mm. The inner diameter of the through-hole of the first sleeve is adapted to the outer diameter of the lead body section.

[0026] In one embodiment of the electrode assembly, the at least one groove extends along the full axial length of the first sleeve. This electrode assembly is cost-effective because manufacturing of the first sleeve is easy. Alternatively, the at least one groove may extend along part of the full axial length of the first sleeve and ends at the inner surface of the through hole. In this case, the inner surface may form a stop surface for shearing and penetration into the electrically insulating material.

[0027] In one embodiment of the electrode assembly, the first sleeve forms a substance-to-substance bond, for example by welding, to the single electrically conducting wire or to the single electrically conducting wire bundle at the at least one cutting edge and / or at the at least one groove. The substance-to-substance bond provides a more reliable electrical connection between the electrically conducting wire or the electrically conducting wire bundle and the first sleeve. The substance-to- substance bond may be provided, e.g., through a borehole extending in radial direction within the first sleeve.

[0028] In one embodiment of the electrode assembly, the first sleeve comprises at least one protrusion, wherein the at least one protrusion extends from a front surface of the first sleeve in axial direction providing an electrical port. Such port may be used to connect an electric member, for example, a

[0029] 24.05 IP- WO / 24.09.2025 shock coil. In one embodiment, the first sleeve may comprise a plurality of such protrusions extending parallel from the same front surface of the first sleeve, i.e. the protrusions are arranged side by side. The at least one protrusion may exhibit a constant width along its axial extension.

[0030] In one embodiment, the first sleeve comprises at least one through hole extending radially from the at least one groove to the outer surface of the electrode member. The at least one through hole provides accessibility to the automatically stripped wire or wire bundle, thereby such that the above- mentioned substance-to-substance bond can be easily facilitated. Additionally, such through hole may provide a peephole perspective with regard to the lead body section thereby simplifying positioning of the first sleeve relative to a pre-defined wire or wire bundle.

[0031] In one embodiment, the electrode assembly comprises a second sleeve fixed to the outer surface of the lead body section coaxially within the first sleeve, wherein the second sleeve comprises a through hole feeding through the single electrically conducting wire or the single electrically conducting wire bundle, each with electrically conducting sheathing. The second sleeve provides an additional electrical insulation of the lead body and its plurality of electrically conducting wires and electrically conducting wire bundles. In one embodiment, the second sleeve comprises a slit extending basically in axial direction from a front surface and ending at its through hole. The slit may at least sectionwise run parallel to the axial direction or curved with regard to the axial direction. Further, the slit of the second sleeve receives one conducting wire or wire bundle with its electrically conductive sheathing, positions it in the through hole and fixes it via clamping, providing a defined position of the wire or wire bundle. This is beneficial for mounting of the first sleeve. In one embodiment, the axial length of the second sleeve is greater than the axial length of the first sleeve. In this case the second sleeve provides additional bending protection for the lead body.

[0032] In one embodiment of the electrode assembly, the at least one groove extends along the inner surface of the sleeve having a curved shape, e.g. a helical shape. For example, the helical shaped groove is represented by a straight line if the inner surface of the first sleeve is projected onto one plane, wherein the straight line is inclined with regard to the axial direction. Alternatively, the at least one groove may have sections with different shapes, e.g. may run in different sections axially and curved. The specific shape of the groove provides further simplification of automatic stripping of the electrically insulating material from the at least one electrically conducting wire or the at least one electrically conducting wire bundle.

[0033] In one embodiment of the electrode assembly, the electrode member is a rod-shaped member extending substantially parallel to an axial direction of the lead body section, wherein the rod-shaped

[0034] 24.05 IP- WO / 24.09.2025 electrode member comprises a fixing element and at least one projection being spaced from one another in said axial direction, wherein the at least one projection exhibits the at least one cutting edge extending along its length and wherein the fixing element forms a positive locking connection with the outer surface of the lead body section. When the rod-shaped electrode member is positioned at its pre-defined location for mounting, the rod-shaped electrode member is pressed against the outer surface of the lead body with the at least one cutting edge shearing and penetrating through the electrically insulating outer layer of the lead body section and / or penetrating through an electrically insulating sheathing of a single electrically conducting wire or through an electrically insulating sheathing of a single electrically conducting wire bundle thereby interlocking with and providing an electrical connection of the electrode member to a single electrically conducting wire or a single electrically conducting wire bundle at the at least one cutting edge. This provides the electrical connection between the rod-shaped member and one electrically conducting wire or wire bundle without the need to pull the wire or wire bundle out of the lead body. Additionally, the positioning of the electrode member on the lead body is more precise such that a specific wire or wire bundle can be chosen for electrical connection to the electrode member.

[0035] The surface section of the rod-shaped electrode member being in contact with the outer surface of the lead body may be flat or curved, wherein in one embodiment the curvature of this surface section corresponds to the curvature of the outer surface of the lead body to provide an excellent fit of the rod-shaped member at the lead body thereby preventing sliding of the electrode member. The fixing element encompasses a part of or the complete circumference of the lead body section forming a positive-locking connection, e.g. a clip-on joint, or penetrates the lead body section forming a friction locking.

[0036] In one embodiment, the at least one projection, may be an integral part of the rod-shaped member or may be an initially separate element. In one embodiment, the at least one projection extends substantially parallel to the fixing element from one surface section of the electrode member. The at least one projection may take, for example, the form of a needle, a pin and / or a blade.

[0037] The fixing element and the at least one projection are arranged at specific, pre-defined positions with a pre-defined distance in axial direction. For example, the fixing element is arranged towards the distal end of the rod-shaped member and the at least one projection is arranged towards the proximal end of the rod-shaped member or vice versa. The distance of the fixing element and the at least one projection is, for example, at least 0,05 mm and the length of the rod-shaped member is, e.g., at least 0,1 mm.

[0038] 24.05 IP- WO / 24.09.2025 In one embodiment of the electrode assembly, the at least one projection is formed by an, for example, initially separate contact pin extending through a through hole of the rod-shaped member. The electrical connection between the rod-shaped member and the at least one conducting wire or wire bundle is facilitated after a fixation of the rod-shaped member on the lead body using the fixing element. In this embodiment, a separate contact pin comprising at least one cutting edge shears and penetrates through the electrically insulating outer layer of the lead body section and / or shears and penetrates through an individual electrically insulating sheathing of one electrically conducting wire or through an individual electrically insulating sheathing of one electrically conducting wire bundle thereby interlocking with and providing an electrical connection of the electrode member to the one single electrically conducting wire or the one single electrically conducting wire bundle at the cutting edge. After or during establishing the electrical connection, the contact pin is fixedly and permanently attached to the rod-shaped member. For example, the contact pin comprises a head forming a formlocking connection with the rod-shaped member. The at least one cutting edge is formed at the shaft and / or the tip of the contact pin, wherein the tip is opposite the head of the contact pin if one considers the axial extension of the contact pin.

[0039] Reliable electrical connection and mechanical fixation of the contact pin is achieved by bending the end of the contact pin located opposite the head providing reliable anchoring of the contact pin within the lead body section and / or by substance-to-substance bond to the rod-shaped electrode member The contact pin can also be designed as a screw or hollow rivet for secure anchoring or can be fixed by another element in the form of a clamp.

[0040] In one embodiment, the contact pin exhibits at least one barb, for example, at its shaft. The at least one barb provides a better anchoring of the contact pin within the electrically insulating material and / or within the electrically conducting material of the wire or the wire bundle. In one embodiment, the at least one barb forms a section of the cutting edge. Accordingly, the reliability of fixation and of electrical connection is increased.

[0041] In one embodiment of the electrode assembly, the electrode member comprises at least two projections, wherein two of the at least two projections form two opposite and converging cutting edges. The electrical connection between the rod-shaped member and the one electrically conducting wire or wire bundle is achieved by interlocking of the cutting edges and this wire or wire bundle, wherein the opposite cutting edges of the two projections penetrate (into) the electrically conducting material of the wire or wire bundle similar to a pair of pliers. Analogously to the above embodiment using the contact pin, the electrical connection to one electrically conducting wire or one electrically

[0042] 24.05 IP- WO / 24.09.2025 conducting wire bundle can be automated. Further, it is advantageous, that the electrode member is integrally formed with the at least two projections.

[0043] Further, the above objective is solved by an implantable medical lead comprising an electrical connector assembly at a proximal end, a lead body extending from the proximal end to a distal end and having a plurality of electrically conducting wires and / or electrically conducting wire bundles and an electrically insulating layer forming an outer surface and an above-described electrode assembly at a distal end section. The implantable medical lead has the advantages that are mentioned above with regard to the above-described electrode assembly.

[0044] In one embodiment, the implantable medical lead may comprise a fixation assembly at its distal end to fix the distal tip of the lead at a pre-defined target location in the patient’s body. In one embodiment, the electrical connector assembly is configured to be connected to a connector of a signal generator and / or a sensing and / or data processing device.

[0045] Another aspect of the invention relates to a method for manufacturing an implantable lead. The method comprises at least the following steps which may be performed, for example, in the following order: (i) providing the lead body, (ii) pulling a single electrically conducting wire with electrically insulating sheathing or a single electrically conducting wire bundle with electrically insulating sheathing out of the lead body and (iii) pushing the electrode member over or along the lead body such that the at least one cutting edge shears and penetrates through the electrically insulating sheathing thereby interlocking with and providing an electrical connection to said single electrically conducting wire or said electrically conducting wire bundle. This method is applicable in particular to an implantable lead comprising an electrode assembly having an electrode member wherein the electrode member is the above-described first sleeve.

[0046] By pushing the electrode member along the lead body, the electrically insulating sheathing of one electrically conducting wire or wire bundle can be at least partially stripped and electrically and mechanically connected to the electrode member in a single step and allows automation. This significantly reduces manufacturing cost. As indicated above, in an embodiment, a subsequent provision of a substance-to-substance bonding / fixing (e.g. welding) may further enhance reliability of the electrical and mechanical connection.

[0047] Another aspect of the invention relates to a method for manufacturing an implantable lead. The method comprises at least the following steps which may be performed, for example, in the following order: (i) providing the lead body, (ii) positioning and / or fixing the electrode member at a pre-defined

[0048] 24.05 IP- WO / 24.09.2025 location at the lead body, e.g. by using the fixing element, and (iii) moving the at least one cutting edge of the at least one projection (e.g. of the contact pin or of the at least two projections) radially to the axial direction of the lead body such that the at least one cutting edge shears and penetrates through the electrically insulating outer layer of the lead body section and / or shears and penetrates through an electrically insulating sheathing of one electrically conducting wire or through an electrically insulating sheathing of one electrically conducting wire bundle thereby interlocking with and providing a reliable electrical connection of the electrode member to a single electrically conducting wire or a single electrically conducting wire bundle at the cutting edge. By moving the at least one cutting edge in a way that the at least one cutting edge interlocks with a single electrically conducting wire or a single electrically conducting wire bundle, an electrical connection between the electrode member and a single electrically conducting wire or a single electrically conducting wire bundle can be established in a single step without any additional stripping step. This significantly reduces manufacturing cost. Automation of these steps is possible. This method is particularly applicable to implantable leads comprising an electrode assembly with a rod-shaped electrode member.

[0049] In one embodiment, the first sleeve may comprise at least one material of the group comprising polyimide and polyetheretherketone, the second sleeve may comprise at least one material of the group comprising platinum (Pt), platinum iridium alloy (Ptlr), gold (Au) alloys and MP35N, the wire or wire bundle may comprise at least one electrically conducting material of the group comprising steel (e.g. MP35N), MP35N filled with silver (MP35N DFT), other nickel-cobalt alloys, stainless steels, gold alloys and platinum alloys, the electrically insulating material of the electrically insulating outer layer and / or of the electrically insulating sheathing may comprise at least one biocompatible material of the group comprising silicone, polyurethane (PU), polytetrafluoroethylene (PTFE), fluorethylene (FEP), perfluoralkoxy polymer (PF A) and polimide (Pi), the rod-shaped member and / or the fixing element and / or the rod-shaped electrode member may comprise at least one material of the group comprising Pt, Ptlr, gold alloys, MP35N, stainless steel, titanium (Ti) and nickel titanium alloy (NiTi).

[0050] The present invention will now be described in further detail with reference to the accompanying schematic drawings, wherein

[0051] Fig. 1 shows a first embodiment of an implantable medical lead with a first embodiment of an electrode assembly in a side view,

[0052] 24.05 IP- WO / 24.09.2025 Fig. 2 depicts an embodiment of a plurality of electrically conducting wire bundles of a lead body in a side view,

[0053] Fig. 3 shows a second embodiment of an electrode assembly with a first embodiment of a first sleeve in a longitudinal section,

[0054] Fig. 4 illustrates the embodiment of a first sleeve of the electrode assembly of Fig. 3 in a perspective side view,

[0055] Fig. 5 shows a second embodiment of a first sleeve of an electrode assembly in a perspective side view,

[0056] Fig. 6 depicts a third embodiment of a first sleeve of an electrode assembly in a perspective side view,

[0057] Fig. 7 illustrates a fourth embodiment of a first sleeve of an electrode assembly in a perspective side view,

[0058] Fig. 8 illustrates a fifth embodiment of a first sleeve of an electrode assembly in a perspective side view,

[0059] Fig. 9 shows the embodiment of a first sleeve of Fig. 9 in another perspective side view,

[0060] Fig. 10 illustrates a section of a sixth embodiment of a first sleeve of an electrode assembly in a perspective side view,

[0061] Fig. 11 depicts a third embodiment of an electrode assembly in a longitudinal section,

[0062] Fig. 12 shows an embodiment of a second sleeve of the electrode assembly of Fig. 11 in a perspective side view,

[0063] Fig. 13 depicts a fourth embodiment of an electrode assembly with a first embodiment of a rodshaped electrode member in a longitudinal section,

[0064] Fig. 14 illustrates a second embodiment of a rod-shaped electrode member in a cross-sectional view,

[0065] 24.05 IP- WO / 24.09.2025 Fig. 15 depicts the embodiment of a rod-shaped electrode member of Fig. 14 in another cross section,

[0066] Fig. 16 illustrates a third embodiment of a rod-shaped electrode member in a cross section,

[0067] Fig. 17 shows a contact pin of the embodiment of a rod-shaped member of Fig. 16 in a longitudinal section.

[0068] Fig. 1 shows an embodiment of an implantable medical lead 1. In this example, the implantable medical lead 1 comprises an electrical connector assembly 20 located at a proximal end, wherein the electrical connector assembly 20 comprises a plurality of electrical terminals arranged thereon to interface with a signal generator or a signal processing unit. A lead body 10 extends from a distal end of the implantable medical lead 1 to its proximal end. Towards the distal end, one section 31 of the lead body 10 functions as an electrode assembly 30. Each electric terminal of the electrical connector assembly 20 is connected to one respective electrode member 34 located at the lead body’s outer surface 11 via one respective conducting wire 33 or wire bundle extending within the lead body 10.

[0069] In one example, each electrode member 34 is fixed at the lead body’s outer surface 11 and electrically connected to one conducting wire 33 or wire bundle.

[0070] Fig. 2 shows a braided pattern 48 of two first conducting wire bundles 53a and two second conducting wire bundles 53b, each consisting of twisted ropes of steel filaments (e.g. MP35N) and each comprising an electrically insulating sheathing cover consisting of PTFE, wherein the first conducting wire bundle 53a has a greater diameter than the second conducting wire bundle 53b. Further, the braided pattern comprises four electrically insulating filaments 47 helically and alternating wound around a core member 56 in opposite direction thereby keeping the wire bundles 53a, 53b with their electrically insulating sheathing at a pre-defined distance. The core member 56 may be, for example, a DFT wire having a silver core and a steel sheath material (e.g. MP35N). In one embodiment, a lead body may be formed using such braided pattern and an electrically insulating cover layer of PU material applied such that this material fills the interspaces in the braided pattern 48 and forms an electrically insulating outer layer and the outer surface of the lead body. The PU material coating may be provided by a reflow process, for example. Other braided patterns comprising a plurality of wires or wire bundles can be used, as well.

[0071] 24.05 IP- WO / 24.09.2025 A second embodiment of an electrode assembly 130 is depicted in Fig. 3. The electrode assembly 130 comprises a lead body section 131 of a lead body 110, a plurality of electrically conducting wires 133 extending within the lead body 110, wherein each wire 133 comprises a separate electrically insulating sheathing (not shown). The wires 133 with their electrically insulating sheathing form a braided structure which is simplified to straight lines in Fig. 3, thereby making Fig. 3 easier to understand. The wires 133 with their individual electrically insulating sheathing are covered by another electrically insulating material forming the electrically insulating outer layer and an outer surface 111 of the lead body 110. The electrode assembly 130 further comprises an electrode member realized as tubular first sleeve 134 (i.e. a first embodiment of a first sleeve) which is depicted in further detail in Fig. 4. The first sleeve 134 comprises one straight groove 140 extending along the axial direction of the first sleeve 134 within its inner surface 139. The groove 140 extends along the entire axial length of the first sleeve 134 and forms two cutting edges 141, one at each rim / edge of the groove 140 formed at the transition of the inner surface 139 of the first sleeve to the groove 140. The width of the groove 140 may be, e.g., 0,15 mm and the depth of the groove 140 may be, e.g., 0,10 mm and the distance of the cutting edges 141 of one groove 140 in circumferential direction is, for example, 0,15 mm. The length of the first sleeve 134 and, accordingly, of the groove 140 may be, e.g., 3,0 mm. The first sleeve 134 is fixedly attached to the outer surface 111 of the lead body 110. The first sleeve 134 further comprises a through hole 145 extending in radial direction from the outer surface 134a of the first sleeve 134 and ending in the groove 140 of the first sleeve. One wire

[0072] 133 of the plurality of conducting wires 133 is accommodated within and directly contacts the groove 140 of the first sleeve. During manufacturing process, the individual electrically insulating sheathing of the wire 133 was automatically stripped by the cutting edges 141 provided by the groove 140 as explained below in more detail. Accordingly, the single wire 133 is electrically connected to the first sleeve 134.

[0073] The manufacturing method of the electrode assembly 130 is explained in the following. In a first step the lead body 110 and the first sleeve 134 are provided. In a second step, one section of the electrically conducting wire 133 having its individual electrically insulating sheathing is pulled out of the lead body 110. Alternatively, the pre-defined electrically conducting wire may be produced such that it forms a protruding loop during manufacturing of the lead body. Afterwards, the first sleeve 134 is coaxially aligned with the outer surface 111 of the lead body 110 such that the groove 140 and the pulled out wire 133 with its electrically insulating sheathing align. In the next step, the first sleeve

[0074] 134 is pushed along the lead body 110 in axial direction (i.e. from right to left in Fig. 3), wherein at the same time the electrically insulating sheathing is sheared by the cutting edges 141 of the groove 140. The cutting edges 141 penetrate into the electrically insulating sheathing of the single wire 133 as well as into the electrically conducting wire material and thereby interlocks with the wire 133.

[0075] 24.05 IP- WO / 24.09.2025 Accordingly, an electrical connection of the wire 133 and the first sleeve 134 is created such that electrical signals may be transmitted from the outer surface 134a of the first sleeve to the wire 133 or vice versa, wherein the outer surface 134a of the first sleeve 134 forms a functional surface for, e.g., a therapy application or sensing. The first sleeve 134 may be additionally crimped such that its outer and inner diameter are reduced, thereby providing an additional fixation at the lead body 110. Additionally or alternatively, the first sleeve 134 may be welded to the single wire 133 using the through-hole 145 thereby providing an additional fixation and electrical connection of the single wire 133 and the first sleeve 134. In one embodiment, the through-hole 145 may be used to monitor the correct position of the single wire 133 within the groove 140. The through-hole 145 may have a diameter of 0,15 mm.

[0076] In the following, further embodiments of first sleeves are depicted in Fig. 5 to 10. The reference numbers of elements of the first embodiment of the first sleeve 134 correspond to the elements of the further embodiments having similar reference numbers in their ones and tens digit (but differ in their hundreds digit). Accordingly, it is referred to the explanation of the first embodiment of a first sleeve 134 in this regard.

[0077] Fig. 5 shows a second embodiment of a first sleeve 234 having a tubular shape. The first sleeve 234 comprises eight grooves 240 at its inner surface 239 extending over the entire axial length of the first sleeve 234 and parallel to the axial direction along the inner surface 239 of the first sleeve 234. Each groove 240 comprises two cutting edges 241 at its rim. The grooves 240 are evenly spaced over the circumference of the through-hole 245 of the inner surface 239 of the first sleeve 234.

[0078] Fig. 6 illustrates an embodiment of a first sleeve 334 having a plurality of straight grooves 340 extending in axial direction at the inner surface of the first sleeve 334. The outer surface of the first sleeve 334 comprises two opposite flat surfaces 334a and a pair of grooves 336 extending at each side surface in axial direction. The flat surfaces 334a provide large surfaces, e.g. for contact with the patient’s tissue. All in all, the shape of the outer surfaces of the first sleeve 334 is substantially cuboid.

[0079] A fourth embodiment of a first sleeve 434 shown in Fig. 7 has a tubular shape similar to the second embodiment depicted in Fig. 5. The first sleeve 434 comprises additionally a plurality of projections 444 extending from one front surface of the first sleeve 434 providing a flange for shock coil attachment. The axial length of such projection 444 may be, for example, 0,5 mm.

[0080] Another embodiment of a first sleeve 534 is illustrated in Fig. 8 and 9, wherein this embodiment is very similar to the third embodiment shown in Fig. 6. The outer surface of the first sleeve 534 is

[0081] 24.05 IP- WO / 24.09.2025 substantially cuboid but each side surface has only one groove 536 (instead of two grooves 336 of the third embodiment). Additionally, for each groove 540 at the inner surface 539 of the first sleeve 534 one through-hole 545 extending in radial direction is provided. However, at each flat surface 534a only one through-hole 545 is arranged. Accordingly, the respective wire or wire bundle may be fixed by welding to the first sleeve 534 using one through-hole 545 notwithstanding the used groove 540 for stripping the wire or wire bundle.

[0082] In another example, the tubular first sleeve 634 comprises a curved groove 640 extending in a curved shape at the inner surface 639 of the first sleeve 634 as depicted in Fig. 10. Such a curved shape of the groove 640 may be advantageous when the first sleeve 634 is rotated relative to the lead body during stripping of electrically insulating sheathing of the wire / wire bundle.

[0083] Fig. 11 depicts a second embodiment of an electrode assembly 230 comprising the first sleeve 134 as shown in Fig. 3 and 4. Furthermore, the lead body 110 corresponds to the lead body shown in Fig. 3 and forms a lead body section 131 having the outer surface 111. The electrode assembly 230 comprises additionally a substantially tubular second sleeve 260 fixed to the outer surface 111 of the lead body 110 coaxially with the first sleeve 134. The second sleeve 260 is arranged between the lead body section 131 and the first sleeve 134 and is depicted in Fig. 12. The second sleeve 260 exhibits a through hole 265 and a slit 266 extending in radial direction from the through hole 265 to the front surface of the second sleeve 260. During manufacture of the implantable medical lead, the second sleeve 260 is coaxially aligned with the lead body 110 and slid over the lead body’s outer surface 111 prior to mounting the first sleeve 134. The pulled-out wire 133 with its electrically insulating sheathing (not shown) is fixed (clamped) in the through hole 265 of the second sleeve 260 and thereby securely kept in place when the first sleeve 134 is moved relative to the lead body 110 and the second sleeve 260. The further manufacture of the implantable medical lead is similar to the one described with regard to Fig. 3.

[0084] In one embodiment, the axial length of the second sleeve 260 is greater than the axial length of the first sleeve 134, so that additional bending resistance for the lead body 110 is provided. Further, the second sleeve 260 provides an additional electrical insulation. The material of the second sleeve 260 is, e g., PEEK.

[0085] Fig. 13 illustrates another embodiment of an electrode assembly 230 that can be used, for example, for an implantable medical lead 210 having an inner lumen 215. Electrically conducting wire bundles 253a and 253b a helically wound around the inner lumen 215 forming a braid. Electrically insulating material 254 is provided at the interspace between the electrically conducting wire bundles 253a and

[0086] 24.05 IP- WO / 24.09.2025 253b forming an electrically insulating outer layer and an outer surface 211 of the medical lead 210. A lead body section 231 of the medical lead 210 comprises a rod- and U-shaped electrode member 670 extending in axial direction of the lead body section 231, wherein the rod-shape relates to the axial direction and the U-shape relates to the circumferential direction. The electrode member 670 further forms a functional surface 670a located at a side opposite the lead body section 231. At one end (in axial direction) the electrode member 670 comprises a through-hole 672 and at the opposite end (in axial direction) the electrode member 670 comprises a fixing element 674. The electrical connection between one conducting wire bundle 253a and the rod-shaped electrode member 670 is facilitated by a contact pin 680 extending through the through hole 672 of the rod-shaped electrode member 670, through the conducting wire bundle 253a and into the inner lumen 215 of the lead body section 231 where the tip of contact pin 680 is bent for fixation. The contact pin 680 comprises at least one cutting edge 681 extending along the shaft of the contact pin 680 and shearing as well as penetrating into the electrically insulating material 254. Further, the cutting edge 681 interlocks with the electrically conducting material of the wire bundle 253a. The fixing element 674 is formed as a pin and extends from the rod-shaped electrode member 670 radially into the lead body section 231, in particular through the electrically insulating material 254 forming an outer layer and into the inner lumen 215. It fixes the rod-shaped electrode member 670 by friction locking. In one embodiment, the fixing element 674 is integrally formed with the rod-shaped electrode member 670. In one embodiment, a separate contact pin 680 is welded by its head 682 to the through-hole 672 of the electrode member 670. The electrode member 670 forms a functional surface 670a at a side formed opposite the lead body section 231, for example in a section of the rod-shaped electrode member 670 located in axial direction between the contact pin 680 and the fixing element 674.

[0087] A second embodiment of a rod-shaped electrode member 770 is illustrated in Fig. 14 and 15. The rod-shaped electrode member 770 having a functional surface 770a located opposite the surface that is in contact with the outer surface of the lead body section. The electrode member 770 comprises two legs 774 extending from the electrode member 770 such that these legs 774 at least partially encompass the outer surface of the lead body section thereby fixing the rod-shaped electrode member 770 by a positive locking connection at the lead body section, for example by snap-fitting. The two legs 774 forming fixing elements have a pre-defined distance in axial direction from two projections 772 penetrating into the lead body section. In particular, the two projections 772 form two opposite and converging cutting edges 771, wherein these cutting edges shear and penetrate through the electrically insulating material 254 and interlock with the wire or wire bundle of the lead body section thereby providing an electrical connection of the rod-shaped electrode member 770 to the wire or wire bundle.

[0088] 24.05 IP- WO / 24.09.2025 Alternatively, in a third embodiment of a rod-shaped electrode member 870, the projection having the at least one cutting edge is formed by a contact pin 880 extending through a through hole of the rod-shaped electrode member 870 as shown in Fig. 16. The shaft of the contact pin 880 forms a first cutting edge 881a and the tip of the contact pin 880 forms a second cutting edge 881b. Additionally, the shaft of the contact pin 880 comprises two barbs 885 providing an additional fixation of the contact pin 880 within the electrically insulating and electrically conducting material. In one embodiment, a head 882 of the contact pin 880 may be welded to the rim of the through-hole of the rod-shaped electrode member 870.

[0089] The manufacturing method of an implantable medical lead using a rod-shaped electrode member 670 is explained in the following. The manufacturing method using the further, above-explained embodiments of rod-shaped electrode members 770 and 870 is similar. In a first step of the manufacturing method the lead body 210 and the rod-shaped electrode member 670 are provided. In a second step, the rod-shaped electrode member 670 is aligned with the lead body 210 in a way, that the fixation pin 674 may penetrate into the lead body section 231 where there is no wire bundle 253a, 253b. At the same time, the through-hole 672 of the rod-shaped electrode member 670 is moved to a pre-defined position at the outer surface 211 of the lead body section 231 above a pre-defined electrically conductive wire bundle 253a. During positioning, the through-hole 672 of the electrode member 670 may be used as a peephole. After correct positioning, the contact pin 680 is pushed through the through hole 672 in a way that its cutting edge 681 shears and penetrates into the electrically insulating outer layer of the electrically insulating material 254 of the lead body section 231 and (if applicable) the electrically insulating sheathing of the electrically conducting wire bundle 253a and interlocks with the wire bundle 253a. In case the contact pin 680 extends into the inner lumen 215 of the lead body section as illustrated in Fig.13, the tip located opposite the head 682 of the contact pin 680 may be bent, e.g. by a flat mandrel. Additionally, the head 682 may be welded to the rim of the through hole 672 for reliable fixation of the contact pint 680 at the rod-shaped electrode member 670.

[0090] The above explained embodiments of implantable medical leads with electrode assemblies and respective manufacturing methods show that cost-effective and automatable manufacture of such devices can be realized, for example for implantable therapy and sensor devices. Separate stripping may be omitted thereby avoiding splitting of the wire or wire bundles. The electrode members are reliably fixed to the lead body and provide a permanent electrical connection to a single, pre-defined wire or wire bundle of the lead body.

[0091] 24.05 IP- WO / 24.09.2025

Claims

Claims1. An electrode assembly (30, 130, 230) for an implantable medical lead (1) comprising- a lead body section (31, 131, 231) with a plurality of electrically conducting wires (33, 133) and / or electrically conducting wire bundles (53a, 53b, 253a, 253b) and an electrically insulating outer layer forming an outer surface (11, 111, 211), and- an electrode member (34, 134, 234, 334, 434, 534, 634, 670, 770, 870) fixed to the outer surface (11, 111, 211) of the lead body section (31, 131, 231), wherein the electrode member (34, 134, 234, 334, 434, 534, 634, 670, 770, 870) comprises at least one cutting edge (141, 241, 341, 441, 541, 641, 681, 771, 881a, 881b) shearing and penetrating through the electrically insulating outer layer of the lead body section (31, 131, 231) and / or shearing and penetrating through an electrically insulating sheathing of a single electrically conducting wire (33, 133) or through an electrically insulating sheathing of a single electrically conducting wire bundle (53a, 53b, 253a, 253b) thereby interlocking with and providing an electrical connection of the electrode member (34, 134, 234, 334, 434, 534, 634, 670, 770, 870) to the single electrically conducting wire (33, 133) or the single electrically conducting wire bundle (53a, 53b, 253a, 253b) at the cutting edge (141, 241, 341, 441, 541, 641, 681, 771, 881a, 881b).

2. The electrode assembly (30, 130) of claim 1, wherein the electrode member is a first sleeve exhibiting at least one groove (140, 240, 340, 440, 540, 640) on its inner surface (139, 239, 339, 439, 539, 639), wherein the at least one groove (140, 240, 340, 440, 540, 640) extends in an axial direction of the first sleeve (134, 234, 334, 434, 534, 634) and forms at least one cutting edge (141, 241, 341, 441, 541, 641).

3. The electrode assembly (30, 130) claim 2, wherein the at least one groove (140, 240, 340, 440, 540, 640) extends along the full axial length of the first sleeve (134, 234, 334, 434, 534, 634).

4. The electrode assembly (30, 130) of any one of the claims 2 to 3, wherein the first sleeve (134, 234, 334, 434, 534, 634) forms a substance-to-substance bond, for example by welding, to the single electrically conducting wire (33, 133) or to the single electrically conducting wire bundle (53a, 53b, 253a, 253b) at the at least one cutting edge (141, 241, 341, 441, 541, 641) and / or at the at least one groove (140, 240, 340, 440, 540, 640).24.05 IP- WO / 24.09.20255. The electrode assembly (130) of any one of the claims 2 to 4, wherein at least one protrusion (444) extends from a front surface of the first sleeve (434) in axial direction providing an electrical port.

6. The electrode assembly (30, 130) of any one of the claims 2 to 5, wherein the first sleeve (134, 234, 434, 534) comprises at least one through hole (145, 245, 445, 545) extending radially from the at least one groove (140, 240, 440, 540) to the outer surface (134a, 234a, 434a, 534a) of the electrode member (134, 234, 434, 534).

7. The electrode assembly (230) of any one of the claims 2 to 6, comprising a second sleeve (260) fixed to the outer surface (111) of the lead body section (131) coaxially within the first sleeve (134), wherein the second sleeve (260) comprises a through hole (265) feeding through the single electrically conducting wire (133) or the single electrically conducting wire bundle, each with electrically conducting sheathing.

8. The electrode assembly (130) of any one of the claims 2 to 7, wherein the at least one groove (640) extends along the inner surface (639) of the first sleeve (634) having a curved shape, e.g. a helical shape.

9. The electrode assembly (230) of claim 1, wherein the electrode member is a rod-shaped electrode member (670, 770, 870) extending substantially parallel to an axial direction of the lead body section (231), wherein the rod-shaped electrode member (670, 770, 870) comprises a fixing element (674, 774) and at least one projection (680, 772, 880) being spaced from one another in said axial direction, wherein the at least one projection (680, 772, 880) exhibits the at least one cutting edge (681, 771, 881a, 881b) extending along its length and wherein the fixing element (674, 774) forms a positive locking connection with the outer surface (211) of the lead body section (231).

10. The electrode assembly (230) of claim 9, wherein the at least one projection is formed by a contact pin (680, 880) extending through a through hole (672) of the rod-shaped electrode member (670, 770, 870).

11. The electrode assembly (230) of claim 10, wherein the contact pin (880) exhibits at least one barb (885).24.05 IP- WO / 24.09.202512. The electrode assembly (230) of any one of the claims 9 to 11, wherein the electrode member (770) comprises at least two projections (772), wherein two of the at least two projections (772) form two opposite and converging cutting edges (771).

13. An implantable medical lead (1) comprising an electrical connector assembly (20) at a proximal end, a lead body (10, 110, 210) extending from the proximal end to a distal end and having a plurality of electrically conducting wires (33, 133) and / or electrically conducting wire bundles (53a, 53b, 253a, 253b) and an electrically insulating layer forming an outer surface (11, 111, 211) and an electrode assembly (30, 130, 230) of any one of the previous claims at a distal end section.

14. A method for manufacturing an implantable lead of claim 13 if it refers to any one of the claims 1 to 8 comprising the following steps:- Providing the lead body (110),- Pulling a single electrically conducting wire (133) with electrically insulating sheathing or a single electrically conducting wire bundle with electrically insulating sheathing out of the lead body (110), and- Pushing the electrode member (134, 234, 334, 434, 534, 634) over or along the lead body (110) such that the at least one cutting edge (141, 241, 341, 441, 541, 641) shears and penetrates through the electrically insulating sheathing thereby interlocking with and providing an electrical connection to said single electrically conducting wire (133) or said electrically conducting wire bundle.

15. A method for manufacturing an implantable lead of claim 13 if it refers to any one of claims1 and 9 to 12 comprising the following steps:- roviding the lead body (210),- Positioning and / or fixing the electrode member (670) at a pre-defined location at the lead body (210), and- Moving the at least one cutting edge (681) radially to the axial direction of the lead body (210) such that the at least one cutting edge (681) shears and penetrates through the electrically insulating outer layer of the lead body section (231) and / or shears and penetrates through an electrically insulating sheathing of one electrically conducting wire or through an electrically insulating sheathing of one electrically conducting wire bundle (253a) thereby interlocking with and providing an electrical connection of the electrode member (670) to a single electrically conducting wire or a single electrically conducting wire bundle (253a) at the cutting edge (681).24.05 IP- WO / 24.09.2025

Images