WO2025008125A1

WO2025008125A1 - Implantable medical device and assembly method for such device

Info

Publication number: WO2025008125A1
Application number: PCT/EP2024/065408
Authority: WO
Inventors: Jan Romberg; Marcel Starke; Jutta MUENTJES
Original assignee: Biotronik SE and Co KG
Current assignee: Biotronik SE and Co KG
Priority date: 2023-07-05
Filing date: 2024-06-05
Publication date: 2025-01-09
Anticipated expiration: 2026-01-05

Abstract

The invention refers to an implantable medical device comprising at least one first housing component (10, 11) and a circuit board (6) with an electrically isolating, plate-like and rigid substrate (7) supporting and/or integrating at least one electronic module (8). In order to produce the medical device cost-effective, the substrate comprises a first portion (7a) and a second portion (7b), wherein the first portion of the substrate and the at least one first housing component are assembled such that the at least one first housing component and the first portion of the substrate form sections of the housing of the medical device and that the at least one electronic module is located inside the housing and is covered by the housing, wherein the second portion of the substrate projects from the housing and is located outside the housing, wherein the first portion and the second portion of the non-conductive substrate are integrally formed. The invention further refers to an assembly method for such implantable medical device.

Description

Implantable medical device and assembly method for such device

The present invention refers to an implantable medical device and an assembly method for such implantable medical device.

Active or passive implantable medical devices (IMD), for example implantable spinal cord stimulation devices, defibrillators, conventional pacemakers or implantable intracardiac pacemakers (also known as leadless pacemakers), monitoring device are well known miniaturized medical devices which may be implanted into or at the patient's body. Pacemakers apply electrical stimulation in the form of pulses to the heart in order to generate a physiologically appropriate heartrate and/or in the form of shocks for cardioversion or defibrillation in order to restore a more normal heart rhythm. Alternative or additional functions of IMDs comprise providing other electrical or electromagnetic signals to the patient as well as measuring or surveilling of body activities, for example by an implantable loop recorder (ILR), such as a heart rate, heart rhythm, blood pressure, blood sugar, oxygen levels and/or alike.

Usually, the hermetically sealed housing of the IMD comprises an electronic module (e.g. a printed circuit board with mounted electronics components, for example a processor for data processing and/or signal generating and an energy source (e.g. a battery, a capacitor, or coil, for wireless charging). A header assembly, generally fixed to the distal end of the IMD, provides the electric connection of the electronic module within the housing to at least one electrode or an electrode socket for an electrode lead using a feedthrough component. Further, the header hermetically seals the housing of the IMD at its distal end.

A conventional cardiac pacemaker (or artificial pacemaker) generates electrical pulses as indicated above, wherein the pulses are delivered by electrodes connected to or fixed at the pacemaker in order to cause the heart muscle chambers (i.e. the atria and/or the ventricles) to contract and therefore pump blood. Further, it senses the natural electrical signals produced by the heart by the electrodes and, if applicable, the heart contractions. Other sensors (e.g. motion sensors) can be implemented, as well. By providing the electrical pulses this device replaces and/or regulates the function of the electrical conduction system of the heart in order to maintain the adequate heart rate, either because the heart's natural pacemaker is not fast enough, or because there is a block in the heart's electrical conduction system. Additionally or alternatively, the pacemaker stimulates different positions within the ventricles to improve the synchronization of the ventricles or provides defibrillation functions in order to treat life-threatening arrhythmias. Modern pacemakers are externally programmable, are configured to transmit measurement values to external devices and allow a health care practitioner (HCP) to select the optimal pacing mode(s) for individual patients.

Accordingly, it is an objective of the present invention to provide an implantable medical device which is more cost-effective. Similarly, it is an object of the present invention to define a more simplified assembly method that has automation capability.

The above object is solved by the implantable medical device with the features of claim 1 and the assembly method with the features of claim 10.

In particular, the above object is solved by an implantable medical device (IMD) comprising at least one first housing component and a circuit board with an electrically isolating, planar or plate-like substrate, a conductor structure arranged on or integrated in the substrate, and one or more electronic components mounted on the circuit board, wherein the substrate comprises a first portion and a second portion, wherein the first portion of the substrate and the at least one first housing component are assembled such that the at least one first housing component and the first portion of the substrate form sections of the housing of the medical device, and the second portion of the substrate projects from the housing and is located outside the housing, wherein the first portion and the second portion of the electrically insulating substrate are integrally formed. The second portion may be formed like a projecting tab, flap or lug. The substrate may comprise additional portions, which project from the housing and are located outside the housing, wherein the additional portions and the first portion are integrally formed.

The IMD may be, for example, a defibrillator, a conventional pacemaker, a monitoring device, a sensor, or a pacemaker device having an integrated defibrillator function. According to an embodiment, the IMD may be a neurostimulation implant in the form of a spinal cord stimulation device, a vagus nerve stimulation device, a brain stimulation device or a muscle stimulation device.

The at least one housing component may comprise an electrically conducting material, for example a metal. Further, the material of the first housing may be biocompatible. Furthermore, the at least one first housing component may comprise different materials, such as a material combination or a composite material. Possible suitable materials for the at least one first housing component are biocompatible and conducting metals and metal alloys such as titanium, titanium alloys, stainless steels (such as 316L), other alloys such as MP35N, conducting and biocompatible plastic materials, and plastic or ceramic composite materials.

As indicated above, the circuit board comprises a substrate that is electrically insulating. The substrate is further formed planar, and may be designed as a flexible, rigid, or rigid-flexible substrate. In one embodiment, the substrate comprises at least one material of the group comprising Polyimides, Liquid Crystal Polymers (LCPs), Glass-Reinforced Epoxy Laminate materials (e.g. FR4), ceramics such as A12O3, ZrO2, Ti2O, composite material with such ceramics, multilayer technology ceramic materials (e.g. high-temperature co-fired ceramics (HTCC), low-temperature co-fired ceramics (LTCC)) or compact ceramics.

According to the invention, the first portion of the substrate forms the housing of the IMD together with the at least one housing component and covers the at least one electronic component and, if applicable, the energy source so that these elements are hermetically sealed. The second portion of the substrate projects from the housing and extends like a header from the housing of the IMD. This increases cost effectiveness during manufacturing and assembling of the IMD, for example by reducing the assembled parts. This advantage is further improved by the below embodiments of the IMD. Particularly, the one or more electronic components of the IMD according to an embodiment of the invention are disposed in the interior of housing. Particularly, the one or more electronic components are configured for picking up and processing electrical potentials, for storing, for further signal processing, and/or signal analysis. Furthermore, one or more electronic components may be configured for delivering electric pulses and for coordinating these pulses, circuit components for wireless data transmission (telemetry) of measured and stored data to external systems or an external patient device at least one trace. The one or more electronic components may include electronic passive or active electronic components, which, by way of example, are passive or active filters, and passive or active assemblies for radio frequency (RF) applications, such as for signal transmission to external devices, or signal transmission within a combination of active implants and/or passive or active assemblies for managing the energy source (e.g. the battery).

In one embodiment, the medical device comprises the first housing component and at least one second housing component separately from the first housing component, wherein the first housing component covers a first side surface of the first portion of the substrate and the at least one second housing component covers a second side surface of the first portion of the substrate, wherein the first housing component, the at least one second housing component and at least a part of the front surface of the first portion of the substrate form sections of the housing of the IMD. In one embodiment, the electrically insulating material of the substrate is disposed between the first housing component and the at least one second housing component and acts like an electrical insulator with regard to the first housing component and the at least one second housing component. Further, the first housing component and the at least one second housing component are spatially separated by the substrate, in particular by its first portion. In one embodiment, there is only one second housing component so that the housing consists of the first housing component, the second housing component and the substrate, wherein the first portion of the substrate is disposed between the first housing component and the second housing component. The shape of the first portion of the substrate is the cutting plane of the first housing component and the second housing component thereby simplifying IMD design. In one embodiment the first housing component and the at least one second housing component are configured as housing shells. In the present context, a "housing shell" is understood to mean a generally shell-formed geometric hollow body having at least one open end, which may be used as part/section of a housing for the IMD. The open end of one of the first and at least one second housing component is closed by the substrate of the circuit board and/or another housing component. A shape of the housing that, after implantation, ensures high patient comfort and a shape that are accompanied by a low risk of infection after implantation and/or those that are easy to implant and, after implantation, are permanently secured at the implantation site, without shifting or rotating, may be used. In one embodiment, the first housing component and the second housing component may have a small overall outside surface relative to the inside volume. Additionally, shapes having few comers and edges, or having rounded corners and edges, may be used. For example, a housing component may be designed as a hollow cuboid having an open side wall or as a paraboloid.

According to one embodiment, the IMD may comprise an antenna, which is integrated in the substrate and/or joined to the substrate, particularly within the second portion of the substrate or within one of the above mentioned additional portions of the substrate. The antenna may be used to send and receive data to/from an external system or an external device, e.g. for the purpose of telemetry. All antenna types and shapes that may be considered useful by a person skilled in the art and that can be integrated on or in the substrate may be used. In one embodiment, the IMD may comprise an antenna formed by the material of the first housing component and the material of the at least one second housing component, in particular by the one second housing component, wherein the first housing component and the at least one second housing component are electrically insulated from one another by the first portion of the substrate. For example, the first housing component and the second housing component form an electrical dipole.

In one embodiment, the conductor structure comprises at least one exposed portion being arranged on the second portion of the substrate, wherein the at least one exposed portion is electrically connected to the one or more electronic components. In one embodiment, the exposed portion is designed in form of a conductive pad, wherein the conductive pad is preferably electrically connected to the remainder of the conductor structure by means of via. In one embodiment, the at least one exposed portion of the second portion is configured to be connected with a plug contact or connector socket. The plug contact or connector socket may be formed as a female connector and may be configured to directly connect a male connection, e.g. of an electrode conductor, e.g. an electrode lead, which is configured to delivery therapeutic electrical pulse to the patient’s tissue and/or to sense physiological electrical pulse from the patient’s tissue.. The electrode conductors, or electrode lead may be additionally mechanical fixed to the connectors, e.g. in a form-fitting, force-fitting or tight manner.

In one embodiment, an energy source, e.g. a primary or secondary battery, or a capacitor is disposed in the interior (inner hollow volume) of the first housing component and/or the at least one second housing component, wherein the interior is covered by the respective housing component. In one embodiment, additionally, the at least one electronic module which does not comprise the energy source, is disposed in the interior of the at least one second housing component so that the energy source is separated from the at least one electronic module by the substrate. In order to electrically connect the energy source with the at least one electronic module, the substrate may comprise a second through-connection.

The conductor structure is particularly designed to transfer electrical energy or couple an electrical signal from the at least one exposed at the second portion of the substrate or the energy source into the one or more electronic components, wherein signal properties and quality of energy transfer are to be preserved to as great an extent as possible.

In one embodiment, the first portion of the substrate forms a cover of the energy source, e.g. a battery or a capacitor. The energy source is designed such that it has a flat shape and the substrate forms a cover of the energy source, e.g. a battery cover. This further reduces the number of parts to be assembled and thereby reduces costs. For example, the substrate may contain the connections to the internal battery structure with corresponding contacts and/or the filling opening of the battery for the electrolyte. In order to manufacture the circuit board, first, the housing of the energy source and the substrate of the circuit board are joined, preferably in fluid-tight manner in order to prevent leakage of potentially harmful substances. Afterwards the energy source is filled and the respective opening is closed. In a further step, the at least one electronic module is mounted to the substrate of the circuit board. Then, the at least one first housing component is joined with the substrate as indicated above (e.g. by selective laser soldering). This special process is used to solder the elements so that the energy source (e.g. the battery) is prevented from heating.

In one embodiment, the first side surface or the second side surface of the first portion of the substrate comprises a recess for arrangement of the energy source. The energy source, for example the battery, is thereby safely arranged within the substrate and can be easily connected with the at least on electronic module.

In one embodiment, the second portion of the substrate partially comprises an electrically insulating and biocompatible coating, wherein the coating comprises, for example, at least one material of the group of materials comprising a parylene, a silicone, or polytetrafluoroethylene. Further, the front surface of the first portion of the substrate may partially or fully comprise such electrically insulating and biocompatible coating, as well.

In an embodiment, the at least one first housing component comprises a coating made of electrically insulating material, wherein at least one first housing component comprises at least one region having no coating made of electrically insulating material. The region preferably does not about any other section of the housing. In one embodiment of the IMD, the at least one first housing component at least partially comprises a coating that improves electrical coupling, such as a fractal coating having surface-enlarging properties, and/or the coating has bioactive properties. The material of the coating may comprise at least one material of the group comprising silicones, parylene, diamond-like carbon (DLC) paints, powder coatings or nano-coatings. Such a coating is used to determine the electrical path from at least one housing component via the tissue (this path represents the electrical measurement and/or stimulation vector). For this purpose, the areas in which the current is to enter or exit the housing component are not coated. Preferably, the current path for the measurement and/or stimulation vector is selected so as to be sufficiently long. The above object is further solved by an assembly method for an implantable medical device (IMD) comprising at least one first housing component and a circuit board with an electrically insulating, planar or plate-like substrate, and conductor structure arranged on or integrated in the substrate, , wherein the substrate comprises a first portion and a second portion which are integrally formed, wherein the method comprises the following steps:

- providing and at least one housing component and a circuit board with an electrically insulating, planar substrate and a conductor structure arranged on or integrated in the substrate (7), wherein the substrate comprises a first portion (7a) and a second portion (7b), and

- joining the at least one first housing component with the first portion of the substrate of the circuit board such that the at least one first housing component and the first portion of the substrate form sections of the housing of the medical device, and the second portion of the substrate projects from the housing and is located outside the housing.

In one embodiment, the method further comprises the step of:

- mounting at least one electronic component on the circuit board (6) within the first portion (7a) of the substrate (7), wherein mounting is conducted before or after joining the at least one housing component (10, 11) and the first portion (7a) of the substrate

The assembling of the circuit board is also referred to as mounting and comprises well- known steps of manufacturing a circuit board, for example, SMT (Surface-Mounted- Technology), bonding or conductive adhesive bonding.

In one embodiment, the joining of the housing sections may be provided by way of a low- temperature solder joint, a laser solder joint, a cold weld joint, a friction weld joint, a fusion weld joint, an adhesive joint or an ultrasonic joint. Thereby, the at least one first housing component is joined (attached) with its front surface to a side surface of the first portion of the substrate, wherein the side surfaces are the opposite surfaces of the planar or plate-like substrate which have the largest area compared with the other surfaces, e.g. the front surface. In one embodiment, there is a first housing component and at least one second housing component. For example, there are just the first and the second housing components which are joined as indicated above to the first portion of the substrate such that the first portion of the substrate is disposed between the first housing component and the second housing component. The first portion of the substrate thereby electrically insulates the first housing component and the second housing component from each other.

In a further embodiment, the medical device comprises an energy source, for example, a battery, or a capacitor. In the above method the step providing a battery and arranging the battery within the volume of the at least one first housing component that is to be covered after joining the at least one first housing component with the first portion of the substrate is added. In particular, if there is just a first housing component and a second housing component, the battery may be arranged such that it is arranged in a volume formed by the substrate and the first housing component which is different from the volume formed by the substrate and the second housing component after joining. In the housing compartment formed by the substrate and the second housing component the one or more electronic components are located so that the battery and the one or more electronic components are accommodated in two different housing compartments separated by the first portion of the substrate. In this case, the one or more electronic components are electrically connected via the conductor structure to the energy source. Thereby an electrical connection between the energy source and the one or more electronic components is established.

The at least one first housing component and the first portion of the substrate are joined such that the join is hermetically sealed. Within the meaning of the invention, "joining" can be understood to mean an attachment of the corresponding components to one another, so that a stable, secure material bond is created, for example by way of soldering, welding or gluing.

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

Fig. 1 shows a circuit board of a first embodiment of an IMD in a side view; Fig. 2 depicts the first embodiment of the IMD in an exploded side view; and

Fig. 3 shows the embodiment of Fig. 2 in an assembled state in a back view.

Fig. 4 shows a circuit board of another embodiment of an IMD in a side view

The Fig. 1 to 3 shown an embodiment of an IMD, for example a pacemaker, having a circuit board 6, a first housing component 10 and a second housing component 11. The circuit board 6 comprises a planer or plate-like substrate 7 with a conductor structure (not shown in Figs. 1 to 3) arranged on or integrated in the substrate 7. Furthermore , the substrate comprises a a first portion 7a, a second portion 7b and one or more electronic components 8, for example a microchip The one or more electronic components 8 are attached to or mounted on the first portion 7a of the substrate 7, e.g. by means of SMT technologies, and electrically connected to at least one of five exposed portions 9 of the conductor structure, wherein the exposes portions are arranged on a surface of the second portion 7b of the substrate by a conductor structure (not shown in Figs 1 to 3). The first portion 7a and the second portion 7b of the substrate 7 are integrally formed.

The substrate 7 may consists of, for example, a polyimide but has preferably a biocompatible and isolating coating 7c, for example consisting of or comprising a a parylene, at its front surface as shown in Fig. 1.

The circumference form of the first portion 7a of substrate 7 corresponds to the outer form and circumference of the first housing component 10 and the second housing component 11 as depicted in Fig. 2. The circumference of the second portion 7b has an approximately rectangular form.

The first housing component 10 and the second housing component 11 have a flat, shell-like shape, wherein for attachment to the circuit board 6 the curving of the respective component is disposed such that between the respective housing component and the circuit board a hollow space is formed after fixation of the respective component to the first portion 7a of the substrate 7 for covering the internal elements of the IMD. The first housing component 10 and the second housing component 11 may consist of, for example, an electrically conductive material, preferably an electrically conductive and biocompatible material, such as titanium, a titanium alloy or stainless steel. The one or more electronic components 8 attached to or mounted on the substrate 7 are accommodated and covered by the hollow space of the first housing component 10, whereas a battery (not shown) is accommodated and covered by the hollow space provided by the second housing component 11. The battery is electrically may be connected to the one or more electronic components 8 prior attachment of the second housing component 11 to the first portion 7a of the substrate 7 by the conductor structure of the substrate 7. The first housing component 10 and the second housing component 11 is joined to the first portion 7a of the substrate, for example, by a low- temperature method like laser soldering or welding or gluing in order to prevent the battery from damage. Accordingly, the first housing component 10 covers a first side surface of the first portion 7a of the substrate 7 and the at least one second housing component 11 covers a second side surface of the first portion 7a of the substrate 7. Further, the join is provided such that it is hermetically sealed, i.e. that the resulting housing is hermetically sealed.

The state after joining the first housing component 10 and the second housing component 11 to the first portion 7a of the substrate is shown in Fig. 3. The first housing component 10, the second housing component 11 and the first portion 7a of the substrate form the housing of the medical device. As one can derive from this figure, the second portion 7b of the substrate extends from the housing and is located outside of the housing so that the exposed portions 9 of the conductor structure are accessible in order to be electrically and mechanically connected to plug contacts or socket (see circle 13 in Fig. 3) having a contacting spring 12.

In another embodiment, shown in Fig. 4, the substrate 7 comprises, besides the second portion 7b, additional sections extending form the housing and be located outside the housing. The additional sections are integrally formed with first portion 7a and the second portion 7b may comprise additionally or alternative exposed portions of the conductor structure, This embodiment may be particularly suitable for medical device that requires additionally outer wirings with sophisticated geometries.. According to the invention, due to the integral structure of the substrate 7 of the circuit board 6 and the structure of the housing, components ( separate feedthrough component and separate header) and process steps (e.g. laser welding processes) are omitted so that the automation potential is increased and throughput time in the overall process chain is greatly reduced.

Claims

1. An implantable medical device comprising at least one housing component (10, 11) and a circuit board (6) with an electrically insulating, substrate (7), a conductor structure arranged on or integrated in the substrate (7), and one or more electronic components (8) mounted on the circuit board (6), wherein the substrate (7) comprises a first portion (7a) and a second portion (7b), wherein the first portion (7a) of the substrate (7) and the at least one housing component (10, 11) are assembled such that the at least one housing component (10, 11) and the first portion (7a) of the substrate (7) form sections of the housing of the medical device and that the at least one electronic component (8) is located inside the housing and is covered by the housing, wherein the second portion (7b) of the substrate (7) projects from the housing and is located outside the housing, wherein the first portion (7a) and the second portion (7b) of the substrate (7) are integrally formed.

2. The medical device of claim 1, wherein the medical device comprises the first housing component (10) and at least one second housing component (11) separately from the first housing component (10), wherein the first housing component (10) covers a first side surface of the first portion (7a) of the substrate (7) and the at least one second housing component c(l 1) overs a second side surface of the first portion (7a) of the substrate, wherein the at least one first housing component (10), the at least one second housing component (11) and at least a part of the first portion of the substrate form sections of the housing of the medical device.

3. The medical device of any of the previous claims, wherein the conductor structure comprises at least one exposed portion being arranged on the second portion (7b) of the substrate (7), wherein the at least one exposed portion is electrically connected with the one or more electronic components (8), wherein particularly the at least one exposed portion is designed in form of a conductive pad. e.

4. The medical device of any of the previous claims, wherein the substrate (7) comprises at least one material of the group comprising Polyimides, Liquid Crystal Polymers (LCPs), Glass-Reinforced Epoxy Laminate materials (e.g. FR4), Low-Temperature- Cofired-Ceramics, High-Temperature-Cofired-Ceramics, Glass, and compact ceramics..

5. The medical device of any of the claims 3 to 4, wherein the at least one exposed portion exposed portion being arranged on the second portion (7b) is configured to be connected with a plug contact or connector socket, wherein the plug contact or connector socket is configured to receive an electrode lead of the implantable medical device.

6. The medical device of any of the previous claims, further comprising an energy source, wherein the first portion (7a) of the substrate forms a cover of the energy source.

7. The medical device of any of the claims 1 to 5, further comprising an energy source, wherein the first side surface or the second side surface of the first portion (7a) of the substrate (7) comprises a recess for arrangement of the energy source.

8. The medical device of any of the previous claims, wherein the second portion of the substrate partially comprises an electrically insulating and biocompatible coating, wherein the coating comprises, for example, at least one material of the group of materials comprising a parylene, a silicone, or polytetrafluoroethylene.

9. The medical device of any of the previous claims, wherein the front surface of the first portion of the substrate at least partially comprises an electrically insulating and biocompatible coating, wherein the coating comprises, for example, at least one material of the group of materials comprising a parylene, a silicone, or polytetrafluoroethylene.

10. The medical device of any of the claims 2 to 9, wherein the medical device comprises one second housing component, wherein the first housing component and the one second housing component are electrically isolated by the first portion of the substrate and form an antenna. 11. An assembly method for an implantable medical device comprising at least one first housing component (10, 11) and a circuit board (6) with an electrically isolating, substrate (7), wherein the substrate comprises a first portion (7a) and a second portion (7b), wherein the method comprises the following steps:

• providing and at least one housing component (10, 11) and a circuit board (6) with an electrically insulating, substrate (7) and a conductor structure arranged on or integrated in the substrate (7), wherein the substrate (7) comprises a first portion (7a) and a second portion (7b);

• joining the at least one housing component (10, 11) with the first portion (7a) of the substrate (7) of the circuit board (6) such that the at least one housing component (10,

11) and the first portion (7a) of the substrate (7) form sections of the housing of the medical device, and the second portion (7 of the substrate projects from the housing and is located outside the housing.

12. The method of claim 11, further comprising the step of:

• mounting at least one electronic component on the circuit board (6) within the first portion (7a) of the substrate (7), wherein mounting is conducted before or after joining the at least one housing component (10, 11) and the first portion (7a) of the substrate.

13. The method of claim 11 or 12, wherein the medical device comprises the first housing component (10) and a second housing component (11), wherein the first housing component (10), the second housing component (11) and the first portion (7a) of the substrate (7) are joined such that the latter is disposed between the first housing component (11) and the second housing component (12).