Method for manufacturing a medical implant

Abstract

A method for producing a medical implant is described, comprising a head portion having at least one blind hole-like recess in the form of an electrical plug contact socket, along which at least one electrically conductive contact element is arranged; and a power supply portion fixedly connected to the head portion, the power supply portion comprising at least one electrical component, preferably in the form of a microcontroller and / or a power supply, the at least one electrical component being electrically connected to the at least one electrically conductive contact element via at least one electrical conductor structure. The method is characterized by the following steps: producing a fixing plate made of a hardenable potting material having a plate top and a plate bottom, the at least one electrical conductor structure being fixed in the fixing plate and thereby extending through the plate top and the plate bottom, arranging the fixing plate in an injection mold such that the plate bottom forms a partial surface of the injection mold, electrically contacting the at least one electrical conductor structure with the at least one electrical component before or after arranging the fixing plate as a partial surface delimiting the injection molded portion, and producing the power supply portion by encapsulating at least one microcontroller, the power supply, and the at least one electrical conductor structure protruding from the plate bottom with the hardenable potting material, thereby forming a material-bonded connection with the plate bottom of the fixing plate.

Description

Technical Field

[0001] The invention relates to a method for producing a medical implant, comprising a head part having at least one blind-hole-shaped recess in the form of an electrical plug contact socket, along which at least one electrically conductive contact element is arranged, and a power supply part fixedly connected to the head part, comprising at least one electrical component, preferably in the form of a microcontroller and / or a power supply, which is electrically connected to the at least one electrically conductive contact element via at least one electrical conductor structure. Background Art

[0002] Implantable medical devices for electrical stimulation of localized internal body regions, temporarily implantable pulse generators (IPGs), for example for defibrillation, pacemaker, and resynchronization applications in cardiac therapy, for neurostimulation therapy such as spinal cord stimulation, brain stimulation, or vagus nerve stimulation, to name a few, each have a self-enclosed housing containing components for generating electrical pulses, such as at least one power source and a circuit structure connected thereto. Furthermore, the housing is connected to a so-called head section, which contains an electrical contact assembly electrically connected to the energy source or the circuit structure. A plug assembly, which is fluid-tightly connected to the head section, can be inserted into the electrical contact assembly and is connected to input and output cables for locally applying electrical stimulation signals in the body and, if necessary, for transmitting locally detected electrical signals in the body to the circuit structure located on the housing side.

[0003] EP 2 134 418 B1 describes a head section of this type for an implantable medical device. The head section comprises two head section housing halves that can be joined along a seam. Semi-cylindrical recesses are formed into each of the head section housing halves, spaced apart by a partition wall, in a series arrangement. Electrically conductive contact ring elements and electrically insulating sealing rings are inserted into the recesses in a series alternating arrangement. The head section, joined by the two head section housing halves, thus comprises an assembly of coaxially oriented and electrically insulating contact ring elements. Lateral access points are provided in the head section for electrical contacting of the contact ring elements, through which an electrical plug assembly can be inserted in a fluid-tight manner into a hollow cavity surrounded by the fully annular contact ring elements.

[0004] Publication DE 10 2012 010 901 A1 discloses a method for positioning and retaining electrical contacts and seals within a head section for electrical contact with an implantable medical device. A blind hole is machined into a head section housing made of a biocompatible and electrically insulating material on one side. Electrically conductive contact rings and annular sealing elements are inserted into the head section housing in an alternating sequence. These contact rings and annular sealing elements together define a hollow cavity into which a rod-shaped plug assembly can be inserted. Each individual annular contact ring is connected within the head section to electrical components located within the housing of the implantable medical device via electrical connecting wires.

[0005] Publication DE 20 2013 012 073 U1 discloses a plug-and-socket module assembly. For assembly, a number of contact rings and sealing elements are arranged in an alternating sequence along a rod-shaped installation tool. All contact rings and sealing elements arranged along the installation tool are clamped together by means of a clamping device while applying an axial joining force. To maintain the joining force, a cartridge element is used, which is axially fixedly attached to the installation tool by means of grub screws. Together with the installation tool head at the end, the cartridge element delimits the assembly consisting of contact rings and sealing elements axially on both sides. In this clamped state, the assembly is cast with a hardenable casting compound, which absorbs the joining force in the hardened state.

[0006] Manufacturing methods for medical implants are known from publications US 2016 / 0 166 825 A1 and US 2008 / 0 033500 A1. In both cases, the power supply part and the head element are encapsulated by a single-piece potting compound at least in the final manufacturing step.

[0007] Publication US 2003 / 0 144 707 A1 discloses an implantable medical device having a surface-contact component.

[0008] Publication DE 10 2017 222 364 A1 describes a method for producing a head portion of an implantable medical device having a plug-in contact socket in which annular contact elements and an electrically insulating sealing ring are arranged in a series. A mounting tool is used to mechanically clamp the annular elements together, which is removed when the medical device is manufactured. The force-exerting, mutual support of the annular elements is then taken over by the hardened plastic base of the head portion. Summary of the Invention

[0009] The present invention is based on the object of further improving a method for producing a medical implant comprising a head portion having at least one blind hole-like recess in the form of an electrical plug contact socket, along which at least one electrically conductive contact element is arranged; and a power supply portion fixedly connected to the head portion, comprising at least one electrical component, preferably in the form of a microcontroller and / or a power supply, which is electrically connected to the at least one electrically conductive contact element via at least one electrical conductor structure, so that the method-related, time-related, and cost-related expenditures for producing implants produced both in individual batches and in large quantities are significantly reduced. Furthermore, it is particularly important to meet the highest requirements for the production quality, fluid-tightness, and associated service life of the implant. Since, for current method-related reasons, the head portion and the power supply portion must be produced in separate production processes, particular attention is paid to joining the head portion and the power supply portion together in order to achieve a permanently fluid-tight joint connection in accordance with the aforementioned production requirements.

[0010] The solution to the object addressed by the present invention is provided in the method according to the invention for producing a medical implant. Features which further develop the inventive concept in an advantageous manner are apparent from the accompanying method and from the contents of the description, in particular with reference to the exemplary embodiments shown in the drawings.

[0011] The method for producing a medical implant according to the solution consists according to the invention of the following method steps.

[0012] Crucial in the production of such medical implants is the realization of a bonded connection between the head part and the current supply part, which, depending on the solution, is achieved in a materially bonded, i.e., integral, manner and thereby ensures a permanently fluid-tight bonded composite between the head part and the current supply part. Regardless of the specific technical design of the head part and the current supply part, these are encapsulated with a biocompatible potting material by a casting method. Both the head part and the current supply part are materially bonded to two opposite upper sides of a connecting plate, also referred to as a fastening plate, which is made of a hardening potting material, with which both the head part and the current supply part are enclosed.

[0013] In order to electrically connect at least one electrically conductive contact element contained in the head part to a microcontroller and a power source, preferably contained in the power supply part, at least one electrical conductor structure is passed through a fastening plate connecting the head part to the power supply part.

[0014] According to the method of the solution, a fixing plate having a plate top and a plate bottom is first produced, which is obtained as a semi-finished product by a casting method using a hardening casting material. During the casting process, at least one electrical conductor structure, preferably in the form of a wire, is oriented and arranged perpendicularly to the plate top and bottom of the fixing plate, so that after the casting material has hardened, the conductor structure is firmly connected to the fixing plate and protrudes from the plate top and bottom.

[0015] Depending on the number of conductive contact elements present within the head section, a corresponding number of conductor structures are provided through the mounting plate. To this end, the conductor structures extending through the mounting plate perpendicularly to the plate's upper and lower sides are distributed within the mounting plate, corresponding to the spatial arrangement of the conductive contact elements within the head section. Instead of embedding the conductor structures within the casting process, the mounting plate can also be manufactured independently of the conductor structures by the casting process. In this case, the conductor structures are then inserted into fine holes through the mounting plate and impregnated with an adhesive, such as a drop of epoxy resin, which secures the conductor structures upon curing and is made of the same material as the head section.

[0016] To produce the power supply, an injection mold is used in a known manner, which determines its external shape and configuration. To prepare for the casting process, at least one electrical component, preferably in the form of a microcontroller and / or power supply, is placed inside the injection mold and connected to at least one electrical conductor structure. According to one embodiment, the injection mold is designed so that a semi-finished fixing plate is integrated into the mold, with the underside of the fixing plate forming a partial surface defining the mold boundary. The at least one electrical conductor structure extending from the underside of the plate and the at least one electrical component are then cast with a hardenable casting compound.

[0017] Within the framework of the casting process, the prepared injection mold is filled with casting material and surrounds the components arranged therein, the flowable casting material infiltrating the plate underside of the fastening plate serving as the injection molded part surface, forming an integral material connection.

[0018] After the potting material has hardened, the power supply part together with the fixing plate fixedly adhered to the power supply part or fixedly connected to the power supply part is removed from the injection mold.

[0019] To produce the head part, firstly at least one electrically conductive contact element is provided and connected to at least one electrical conductor structure protruding from the plate side of the fastening structure.

[0020] The head section is typically provided with a plurality of electrically conductive contact elements, which are designed in the form of contact ring elements and are arranged in a coaxial, axially serial sequence, alternating with electrically insulating, elastically deformable sealing rings and engaging with each other in a force-fitting manner under an axial engagement force. A preferred embodiment of this prestressed stack of contact ring elements, which is integrated into the head section, is explained in detail with reference to the following figures.

[0021] The electrical conductor structures extending from the upper surface of the fixing plate are electrically connected to the respective electrical contact elements disposed within the head section, preferably by soldering, bonding, gap welding, or friction welding. Optionally, additional electrical structures, such as an antenna connectable to corresponding electrical components within the power supply section, may be incorporated into the head section. Furthermore, at least one contact element electrically connected to the electrical conductor structure is cast with a hardenable casting material in such a manner as to form a mating connection with the upper surface of the fixing plate material. The casting process for manufacturing the head section can be performed before, during, or after manufacturing the power supply section.

[0022] As in the case of the casting process for producing the power supply part, a fluid-tight, integral material connection is also formed between the plate side of the fixing plate and the hardening casting material on the head part side, so that all electrical components encapsulated by means of the hardening casting material in the area of ​​the head part, the fixing plate and the power supply part are completely fluid-tightly surrounded by the casting material without any dividing interfaces.

[0023] Biocompatible plastics or epoxy resins are suitable as casting materials for producing the head part, the fastening plate and the power supply part. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention will be described below by way of example with reference to the accompanying drawings, without limiting the overall inventive concept.

[0025] Figure 1 A diagram showing a medical implant constructed according to the solution,

[0026] Figure 2 A view showing a fixing plate with an electrical conductor structure passing through,

[0027] Figure 3 Shows the injection mold used to manufacture the power supply part,

[0028] Figure 4 shows the electrical connection of the electrical conductor structure to the assembly consisting of contact ring elements, and

[0029] Figure 5 A view showing the potting material used to produce the head part. DETAILED DESCRIPTION

[0030] Figure 1 A medical implant 1 manufactured according to the solution is shown, comprising a head part 2, a power supply part 3 and a fixing plate 4, the plate upper side 4 ′ of which is materially connected, i.e. integrally, to the head part 2, and the plate lower side 4″ of which is materially connected, i.e. integrally, to the treatment unit 3.

[0031] The head section 2 has a blind-hole-like recess 5 in the form of an electrical plug contact socket, along which electrical contact elements 6 in the form of contact ring elements are arranged in a series arrangement, each spaced axially apart, with electrically insulating sealing rings 7 located between them. The series arrangement of contact ring elements 6 and sealing rings 7 is subjected to an axial engagement force F, which connects the contact ring elements 6 and sealing rings 7 to each other in a fluid-tight manner. To provide electrical signals and supply energy, the electrical contact ring elements 6 are connected via a wire-like electrical conductor structure 8 to a microcontroller 9 housed within the power supply section 3 and a power source 10 electrically connected to the microcontroller 9. The power source 10 can be designed as a battery, an accumulator, a biofuel cell, or as an inductive coupling circuit for contactless inductive energy transmission. Of course, alternative or additional electrical components can be included in the power supply section 1.

[0032] All components of the medical implant 1 are respectively cast with the same biocompatible casting material, preferably a plastic or resin material, preferably an epoxy resin material.

[0033] To manufacture Figure 1 The medical implant 1 shown in FIG. 4 is a fixing plate 4 according to Figure 2 The device is manufactured from a biocompatible casting material within the framework of a casting method, wherein a wire-like electrical conductor structure 8 passes through the fixing plate 4 perpendicularly to the plate upper side 4 ′ and the plate lower side 4″ of the fixing plate. Optionally, a mechanical connection element 11, preferably in the form of a threaded nut with a screw that can be inserted therein, is inserted into the fixing plate 4 to fix the head part-side series sequence consisting of the sealing ring 7 and the contact ring element 6 in a fixed position (see also Figure 4 The contact ring element / sealing ring element assembly 14 in FIG. 1 can be equipped with corresponding mechanical holding devices (not shown) for additional fastening to the fastening plate 4 by means of screw connections 11 .

[0034] The fixing plate 4, which is designed as a separate semi-finished product and has the wire-like electrical conductor structure 8 fixed therein, further serves as a partial surface for producing and forming an injection mold 12 for the power supply 3. The electrical conductor structure 8 extending from the plate underside 4″ is first electrically connected to the microcontroller 9 and the power supply 10 shown. This electrical connection can be made before or after the fixing plate 4 is placed in the injection mold to define the mold.

[0035] Figure 3 The fixing plate 4 is shown inserted into the injection mold 12, whose plate bottom side 4″ can define the interior of the injection mold 12 in a fluid-tight manner. The injection mold 12 is then completely filled with a biocompatible, hardenable casting material. The biocompatible, hardenable casting material used when filling the injection mold 12 is the same as the casting material forming the fixing plate 4, so that a material-fitting, integral connection is formed between the plate bottom side 4″ of the fixing plate 4 and the casting material.

[0036] according to Figure 4 After the casting process, electrical contact is made between the electrical conductor structure 8 projecting from the plate top 4 ′ of the fastening plate 4 and the contact ring element 6 .

[0037] Figure 4 The axial stack assembly 14 shown in the figure is composed of electrical contact ring elements 6 and sealing rings 7 located between the electrical contact ring elements. It is also a semi-finished product. The stack assembly has a rod-shaped installation tool 13, along which the conductive contact ring elements 6 and the electrically insulating sealing rings 7 made of elastic material located between the contact ring elements are arranged in an axially alternating sequence. The fixing parts 15 and 16 are respectively arranged along the rod-shaped installation tool 13 on both sides of the axial stack assembly 14 consisting of the alternating sequence of contact ring elements 6 and sealing rings 7. Figure 4 In the case of the fixing element 16 shown in FIG, this fixing element is a disk-shaped or circular mechanical stop integrally connected to the further rod-shaped installation tool 13, with the axial stacking component 14 directly adjoining the stop on one side. The fixing element 15, arranged opposite the stop along the axial stacking component 14, is designed to be axially movable along the rod-shaped installation tool 13 and furthermore has a latching mechanism that can secure the fixing element 15 axially immovably relative to the rod-shaped installation tool. Preferably, the fixing element 15 is a nut or a plate with an internal thread that mates with an external thread (not shown) provided on the end side of the rod-shaped installation tool 13.

[0038] In order to apply a joining force which is oriented axially relative to the rod-shaped installation tool 13 and which joins the alternating sequence of contact ring elements 6 and sealing rings 7 to each other in a force-fitting manner, the installation tool 13 is rotated relative to the fixing part 15, for example, by completely screwing the external thread on the installation tool side into the internal thread of the fixing part 15, thereby adjusting a definable and predeterminable joining force acting along the contact ring elements 6 and sealing rings 7 arranged on the installation tool 13.

[0039] Figure 4 The axial stack assembly 14 shown in FIG is a semi-finished product to be processed separately, which is placed in the electrical conductor structure 8 and the electrical contact ring element 6 according to the electrical contact axis. Figure 5 In the injection mold 17. The injection mold 17 is as in the Figure 3 As in the case of the casting process of , the fixing plate 4 is partially delimited by the fixing plate 4, which is integrally connected to the potting material on the power supply side, that is, the plate side 4 ' of the fixing plate 4 is closed in a fluid-tight manner to the rest of the injection mold 17. The casting process is carried out in the same way by using the hardenable potting material described below, from which the fixing plate 4 and the potting body of the power supply part 3 are already formed.

[0040] After the potting compound on the head part has hardened, the medical implant 1 can be removed from the injection mold 17 and the setting tool 13 can be separated by rotating the fixing element 15. The axially generated joining force between the contact ring element 6 and the sealing ring 7 is supported and maintained by the potting compound hardened on the head part.

[0041] Alternatively to the aforementioned method, it is also possible to Figure 5 The casting method is used in the manufacture of Figure 3 The power supply part 3 is cast before or simultaneously with the casting method.

[0042] Reference Signs List

[0043] 1Medical implants

[0044] 2 head part

[0045] 3 Power supply part

[0046] 4 fixed plate

[0047] 4' board upper side

[0048] 4" board underside

[0049] 5Blind hole-like recess

[0050] 6 conductive contact elements, contact ring elements

[0051] 7 Sealing ring

[0052] 8 Electrical conductor structure

[0053] 9. Microcontroller

[0054] 10 Power supply, battery

[0055] 11 Mechanical connectors

[0056] 12 Injection Molding

[0057] 13 Installation Tools

[0058] 14 stacking components

[0059] 15, 16 fixing parts

[0060] 17 Injection molding.

Claims

1. A method for producing a medical implant (1), the medical implant comprising: A head part (2) having at least one blind hole-shaped recess (5) in the form of an electrical plug contact socket, along which at least one electrically conductive contact element (6) is arranged; and a power supply part (3) fixedly connected to the head part (2), comprising at least one electrical component, the at least one electrical component being electrically connected to the at least one electrically conductive contact element (6) via at least one electrical conductor structure (8), The method is characterized by the following method steps: - producing a fixing plate (4) made of a hardenable casting material, having a plate top and a plate bottom (4', 4"), in which the at least one electrical conductor structure (8) is fixed and thereby passes through the plate top and the plate bottom (4', 4"), - arranging the fixing plate (4) in an injection mold (12) so that the plate underside (4") forms part of the surface of the injection mold (12), - before or after arranging the fixing plate (4) as a partial surface for partially delimiting the injection mold (12), electrically contacting the at least one electrical conductor structure (8) with the at least one electrical component, and The power supply part (3) is produced by encapsulating the at least one electrical component and the at least one electrical conductor structure (8) protruding from the plate bottom (4") by means of the hardenable potting material, thereby forming a material-fit connection with the plate bottom (4") of the fixing plate (4).

2. The method according to claim 1, characterized in that The fastening plate (4) is produced by a casting method in which the hardenable casting material is injected into a sheet metal injection mold.

3. The method according to claim 2, characterized in that During the casting process, the injection mold (12) is penetrated by the at least one electrical conductor structure (8).

4. The method according to claim 3, characterized in that At least one hole is machined into the hardened fixing plate (4), the electrical conductor structure (8) is guided through the hole and fixed in the hole by means of an adhesive.

5. The method according to any one of claims 1 to 4, characterized in that At least one electrical conductor structure (8) protruding from the upper side (4') of the plate is electrically connected to the at least one electrically conductive contact element (6), and The at least one electrically conductive contact element (6) is fixedly connected to the fixing plate (4) indirectly or directly.

6. The method according to any one of claims 1 to 4, characterized in that A plurality of electrically conductive contact elements (6) are provided, which are designed in the form of contact ring elements and which alternate with electrically insulating, elastically deformable sealing rings (7) in a coaxial and axially serial sequence and engage with each other in a force-fitting manner under an axial engagement force, and A plurality of contact ring elements and sealing rings (7) arranged in a coaxial and axially serial sequence are fixedly connected to the plate side (4') of the fixing plate (4) after the contact ring elements are each electrically contacted with at least one electrical conductor structure (8) protruding from the plate side (4').

7. The method according to claim 5, characterized in that Before, during or after the production of the power supply part (3), at least one electrically conductive contact element (6) electrically connected to the electrical conductor structure (8) is cast with a hardenable casting material when forming the head part (2), thereby forming a material connection with the plate side (4') of the fixing plate (4).

8. The method according to claim 6, characterized in that Before, during or after the production of the power supply part (3), at least one electrically conductive contact element (6) electrically connected to the electrical conductor structure (8) is cast with a hardenable casting material when forming the head part (2), thereby forming a material connection with the plate side (4') of the fixing plate (4).

9. The method according to any one of claims 1 to 4, characterized in that Use biocompatible polymers as casting materials.

10. The method according to claim 9, characterized in that Biocompatible epoxy resin was used as the casting material.

11. The method according to any one of claims 1 to 4, characterized in that The power supply part (3) constitutes an implantable medical device used as a pulse generator.

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