Mounting and hermetic sealing of a pre-assembled header bodies to a titanium feedthrough

Abstract

The present invention relates to an implantable medical device (1) comprising a first connecting member (400) provided by a header body (40) and a second connecting member (300) connected to a first housing portion (2a) of the implant (1), wherein the first and the second connecting members (400, 300) are configured to engage with each other to mount the header body (40) to the housing (2), and wherein the header body (40) comprises a recess (43) for accommodating an electrically conducting structure (42) and feedthrough pins (30).

Description

[0001] Mounting and hermetic sealing of a pre-assembled header bodies to a titanium feedthrough

[0002] The present invention relates to an implantable medical device and to a method for mounting a header body to a housing portion of an implantable medical device.

[0003] Pre-assembled headers on active implants in which pre-molded components are bonded to a titanium housing are known in the state of the art. Headers as well as housings are pretreated with primer according to their material. The still open welding area of the external wiring is then usually sealed with a silicone.

[0004] Particularly, a welded lug with a hole is used in the prior art to mechanically secure the header on the housing, over which the header is then placed. The assembled system is then secured with a pin.

[0005] The assembly and filling processes known in the art require access to the implant from several directions, which makes these steps difficult to automate. This often results in high costs due to necessary mechanical rework after differential pressure casting. Furthermore, the duration of the curing reaction is often in the range of hours.

[0006] Based on the above, the problem to be solved by the present invention is to provide an implantable medical device and a method for mounting a header to a portion of a housing of an implantable medical device that are improved regarding the above-stated difficulty.

[0007] This problem is solved by an implantable medical device having the features of claim 1.

[0008] Preferred embodiments of this aspect of the present invention are stated in the corresponding claims and are described below. According to claim 1, the implantable medical device comprises: a housing for accommodating an electronics module, the housing comprising a first housing portion and a second housing portion, an electrical feedthrough arranged on the first housing portion, wherein the electrical feedthrough comprises a plurality of feedthrough pins for providing an electrical connection to the electronics module from outside the housing, a header comprising a header body and a connector being accommodated by the header body, wherein the header body mounted to the first housing portion, and an electrically conducting structure connecting the connector to at least one feedthrough pin of said plurality of feedthrough pins.

[0009] According to the invention it is particularly envisioned that the header body comprises a first connecting member configured to engage with a second connecting member connected to the first housing portion to mount the header body to the first housing portion, and wherein the header body comprises a recess for accommodating the electrically conducting structure and the feedthrough pins.

[0010] Particularly, the invention allows an automatable assembly process of a prefabricated or preassembled header onto a feedthrough arranged on a housing portion or generally onto a housing portion of an implantable medical device. Furthermore, in the same device orientation, a dispensing process may be applied to fill the still open outer wiring areas, i.e., said recess, with a potting material, which can also be automated. In combination, this results in strong holding forces between the header and the housing, and the entire outer wiring area (electrically connecting structure) and the feedthrough itself are protected against penetrating body fluids.

[0011] Furthermore, particularly, the present invention allows to use a pre-fabricated injection- molded header body (e.g. out of TPU) instead of differential pressure molding (epoxy) the whole header. Furthermore, the invention addresses the problem of achieving a hermetically sealed bond between the thermoplastic polyurethane (TPU) and the potting material, as well as between the potting material and a titanium alloy surface of the portion of the housing. Particularly, the first connecting member and the second connecting member are designed such that the header body can be mounted to the first housing portion in a slidable manner in one embodiment. In one embodiment, the second connecting member is designed in form a mounting rail arranged on the first housing portion, wherein particularly the mounting rail is integrally from in one piece with the first housing portion, and the first connection member is designed in form of a groove formed in the header body, wherein the header body can be mounted to the first housing portion by slidable engagement of the first connecting member and the second connecting member. Particularly, the mounting rail on the first housing portion is configured to be inserted into the groove in the header body to slidably engage the mounting rail and the groove in order to mount the header body on the first housing portion.

[0012] Particularly, the electronics module is configured to provide a therapy, particularly an electrotherapy, such as for example cardiac pacing, cardia defibrillation, or neurostimulation, and / or the electronics module is configured to sense physiological signal, particularly electrical physiological signal, such as electrical cardiac signal, and / or other physiological signals such as posture, movement, temperature, or concentrations of physiological compounds, e.g., glucose, oxygen, etc. Accordingly, the implantable medical device is designed as a cardiac pacemaker, cardioverter-defibrillator, neurostimulator, or cardiac monitor in one embodiment.

[0013] Particularly, in an embodiment, the recess is filled with a potting material so that the electrically conducting structure and the feedthrough pins are covered by the potting material (e.g. to form the final housing).

[0014] Further, in an embodiment of the implantable medical device according to the invention, the potting material is an epoxy resin (e.g. EPO-TEK 301, Epoxonic EX3635, all biocompatible, cold-curing epoxy resins based on BADGE / TMD are possible here). Particularly, the cured potting material forms a section of an outer surface of a header of the implantable medical device, which outer surface is particularly formed by the header body and the (cured) potting material. Particularly, in an embodiment, the electrical feedthrough or the housing portion comprises at least a one connecting member (particularly two such connecting members) in form of a mounting rail, wherein the header body comprises the corresponding counterpart in an injection molded portion of the header body. The header body may then be automatically mounted from one direction (e.g. in the axial direction of the rail) to a mechanical stop (preferably in a top to bottom mounting movement). Without further movement of the assembly comprising the header body and the electrical feedthrough or housing portion, the electrically conducting structure (e.g. external wiring, particularly external wiring strips) may be mounted in the same orientation in the recess of the header body.

[0015] Particularly in an embodiment, said recess of the header body may be filled with the potting material. The interface between the header body (particularly formed out of TPU) and the potting material may be sealed by plasma activation of the header body (TPU) at atmospheric pressure. A hermetic sealing of the potting material to the titanium alloy surface of the feedthrough or housing may be realized e.g. by laser structuring and subsequent application of an alkoxysilane-based adhesion promoter.

[0016] Furthermore, according to an embodiment of the implantable medical device, the header body is an injection molded header body, and / or wherein the header body is formed (e.g. injection molded) out of or comprises a thermoplastic polyurethane (TPU).

[0017] Furthermore, according to another embodiment of the implantable medical device, the electrical feedthrough comprises at least one electrical insulator through which said feedthrough pins extend, wherein the electrical feedthrough pin further comprises a flange to which the at least one electrical insulator is connected. In an embodiment, the flange is a metal injection molded (MIM) flange. Furthermore, particularly the flange forms the first housing portion, particularly in form of a lid, wherein the first housing portion, particularly in form of a lid, comprises a circumferential edge welded, particularly laser-welded, to a circumferential edge of the second housing portion, particularly in form of a beaker or can, of the housing, wherein the beaker or can accommodate components of the implantable medical device such as a battery etc. Particularly, the cross-sectional area of the first housing portion, particularly the lid, defined by its edge is substantially as large as the cross-sectional area of the second housing portion parallel to the edge of the first housing portion. Or in other words, the cross-sections of the first housing portion and the second housing portion are particularly substantially equal or congruent at its respective circumferential edge, which are intended to be welded.

[0018] Thus, in this case, in other words, the second housing portion does not form an interface to the header body, but only the first housing portion, particularly the flange of the feedthrough, which sits as a lid on the second housing portion and has the aforementioned connecting member(s) (e.g. rail) on its upper side, particularly as integral components. The feedthrough flange itself may be MIM flange, which allows such complex geometries at low cost.

[0019] Furthermore, according to yet another embodiment of the implantable medical device, the second connecting member is a rail extending in an axial direction. The rail is preferably integrally connected to second housing portion or the flange of the electrical feedthrough, respectively. Further, in an embodiment, the first connecting member of the header body is a groove that is preferably formed in the header body (as an integral component thereof), wherein particularly the groove is configured to receive a mounting rail arranged on the first housing portion, particularly for mounting the header body on the first housing portion in a slidable manner. According to one embodiment, the rail comprises an L-shaped cross section. Further, in an embodiment, the groove comprises a corresponding L-shaped cross section.

[0020] Furthermore, according to an embodiment of the implantable medical device, the groove comprises an entrance for receiving the rail (e.g. for insertion of the rail in the axial direction), wherein an L-shaped cross section of the groove at the entrance orthogonal to the axial direction is larger than an L-shaped cross section at a first end of the rail orthogonal to the axial direction, wherein the rail is configured to be inserted into the groove with the first end ahead. This allows the header to be "threaded in" relatively freely and without contact with the flange (e.g., lid) or housing. Alternatively, the rail has a dovetail-shaped crosssection in one embodiment, wherein particularly the header body comprises a respective grove configured to form-fittingly engage with the rail having a dovetail-shaped crosssection.

[0021] Particularly, in other words, the header body, particularly the injection-molded header body, features the negative shape of the rail, with the addition of an enlarged entrance (particularly in the first third) to further facilitate threading.

[0022] Furthermore, according to an embodiment of the implantable medical device, the L-shaped cross section is formed by a base portion and a head portion of the rail, wherein the base portion extends in the axial direction and is connected to the first housing portion, particularly to the flange of the electrical feedthrough. Furthermore, particularly, the rail (second connecting member) may be integrally connected to the flange or to the first housing portion, respectively. Further, in an embodiment, the head portion may be (e.g. integrally) connected to the base portion and may protrude from an end of the base portion in a direction orthogonal to the axial direction of the rail. In a preferred embodiment, the head portion is inclined with respect to the axial direction (e.g. by an angle in the range of about 2° to 3°) such that a height of the head portion over the flange and / or first housing portion decreases starting from the first end towards an opposing second end of the rail. Thus, particularly, only as an insertion of the rail progresses from the first end to its second end, the header body is pressed against the flange and / or first housing portion (e.g. lid) in a direction orthogonal to the axial direction. On the one hand, this simplifies the tolerance situation between the two joining partners and, on the other hand, the placement accuracy in the automatic assembly machine.

[0023] Furthermore, according to an embodiment of the implantable medical device, the rail comprises a latching lug configured to engage with a recess of the groove to secure the header body to the housing when the rail is inserted in the groove. Particularly, the positions of lug and recess of the groove can be interchanged.

[0024] In other words, particularly, both joining partners are equipped with securing means (in this specific case, curved elements such as a latching lug and a corresponding recess), which provide further mechanical retention when the end stop is reached. Furthermore, in one embodiment of the invention, the implantable medical device comprises a third connecting member provided by the header body and a fourth connecting member connected to the first housing portion, wherein the third and the fourth connecting members are configured to engage with each other to mount the header body to the first housing portion. The third and fourth connecting member may be designed according to the embodiments relating to the first and second connecting member. In one embodiment, the head portion of the first and third connecting member protrude in opposite directions from the base portion, particularly away from one another. Particularly, in case the implantable medical device comprises two (first and third) connecting members, particularly rails, the latter extend parallel to one another. However, the head portions of the first and third connection member may also protrude in same direction or towards each other in another embodiment.

[0025] Particularly, in an embodiment, an outer surface portion of the header body, which header body is particularly formed out of a thermoplastic polyurethane (TPU), e.g. Pellethane 2363 75D, Tecothane TT1075DM, Isoplast 2530-E or Elasthane 75D NW, is oxidized by means of atmospheric pressure plasma (before the assembly and potting process). This may be done, for example, by treating the surface following a meandering path (e.g., Plasmatreat Openair-Plasma®).

[0026] Furthermore, according to an embodiment, the flange and / or first housing portion is formed out of titanium or a titanium alloy. Particularly, the first housing portion is formed out of a titanium Grade 4 according to DIN 3.7056, or a metal -injection-molded titanium, particularly MIM-Ti-400 (ISO 22068) in an embodiment. Particularly, the second housing portion is formed out of titanium, particularly titanium grade 4 ASTM F-67. Particularly, an outer surface portion of the joining partner (e.g. flange and / or housing) made of titanium or a titanium) is cleaned, e.g., generally according to DIN 13887, optionally acid-cleaned, and is furthermore preferably wet-chemically oxidized or, in particular, laser-structured, wherein particularly said laser-structuring improves the adhesion of a plastic, e.g., thermoplastic polyurethane or an epoxy resin to the titanium or titanium alloy. In addition, the outer surface portion of the flange and / or housing is particularly pretreated with an adhesion promoter from the alkoxysilane class (e.g. 3-glycidoxypropyltrimethoxysilane, CAS No.: 2530-83-8 or N,N-[bis(3-trimethoxysilyl)propyl]ethylenediamine, CAS No.: 68845-16-9, in each case preferably deposited from acetic acid ethanolic solution (0.1% - 5% alkoxysilane content) by dipping).

[0027] According to a further aspect of the present invention, a header assembly for an implantable medical device is provided, wherein the header assembly comprises: a first housing portion, particularly of a housing of an implantable medical device, an electrical feedthrough arranged on the first housing portion, wherein the electrical feedthrough comprises a plurality of feedthrough pins for providing an electrical connection to an electronics module from outside the housing, a header comprising a header body and a connector being accommodated by the header body, wherein the header body mounted to the first housing portion, and an electrically conducting structure connecting the connector to at least one feedthrough pin of said plurality of feedthrough pins, wherein the header body comprises a first connecting member configured to engage with a second connecting member connected to the first housing portion to mount the header body to the first housing portion, and wherein the header body comprises a recess for accommodating the electrically conducting structure and the feedthrough pins.

[0028] The header assembly according to the present invention may be further characterized by the features and embodiments described above in conjunction with the implantable medical device according to the invention.

[0029] According to a further aspect of the present invention, a method for providing a header on a first portion (e.g. flange of an electrical feedthrough) of a housing of an implantable medical device, particularly an implantable medical device according to the invention, the portion comprising an electrical feedthrough comprising a plurality of feedthrough pins, wherein the method comprises the steps of: providing a header body accommodating a connector and comprising a first connecting member, mounting the header body to said first portion of the housing by bringing the first connecting member of the header body and a second connecting member connected to said portion of the housing into engagement to mount the header body to said first portion, wherein the header body comprises a recess for accommodating the plurality of feedthrough pins so that the feedthrough pins are accessible from one side, and electrically connecting the connector via an electrically conducting structure to at least one feedthrough pin of an electrical feedthrough comprised by said first portion of the housing, wherein the electrically conducting structure is arranged in said recess.

[0030] Particularly, in one embodiment, the second connecting member is designed in form a mounting rail arranged on the first housing portion, wherein particularly the mounting rail is integrally from in one piece with the first housing portion, and the first connection member is designed in form of a groove formed in the header body, wherein mounting the header body to the first housing portion includes sliding the mounting rail on the first housing portion into the groove in the header body.

[0031] Particularly, in an embodiment the method according to the invention further comprises the steps of filling the recess of the header body with a potting material for forming the header, wherein the electrically conducting structure and the feedthrough pins are covered in the potting material.

[0032] Particularly, in an embodiment, the potting material - once cured - forms an outer surface portion of the header, wherein particularly the complete outer surface of the header is formed by the header body and the potting material bonded thereto.

[0033] Furthermore, according to an embodiment of the method, the header body is injection molded (e.g. out of TPU), and / or wherein the header body is formed out of or comprises a thermoplastic polyurethane (TPU), e.g., Pellethane 2363 75D, Tecothane TT1075DM, Isoplast 2530-E or Elasthane 75D NW. According to a further embodiment of the method, the first portion of the housing is formed out of titanium or a titanium alloy (e.g. titanium Grade 4, ASTM B 265-00, or metal -injection molded titanium MIM-Ti-400). Furthermore, according to yet another embodiment of the method according to the present invention, the electrical feedthrough comprises a flange. In an embodiment the flange is formed by metal injection molding (MIM). Furthermore, in an embodiment, the electrical feedthrough comprises at least one electrical insulator through which said feedthrough pins extend, wherein the electrical insulator is connected to the flange.

[0034] Furthermore, according to an embodiment of the method, the potting material contacts a surface portion of the recess of the header body, wherein prior to the filling of the recess with the potting material, this surface portion of the header body is oxidized by means of atmospheric pressure plasma. This may be done, for example, by applying the plasma along a meandering course (Plasmatreat Openair-Plasma®). Particularly, the application of plasma may be adjustable by the design of the nozzle used for application of the plasma. Particularly, the meandering course or pattern may be reduced by using a broader nozzle for application.

[0035] Furthermore, according to yet another embodiment of the method, the potting material contacts a surface of the first portion (e.g. flange of the electrical feedthrough) of the housing, wherein prior to the filling of the recess with the potting material, the surface of the portion of the housing is pretreated with an adhesion promoter, wherein particularly the adhesion promoter is one of: an alkoxysilane, 3-glycidoxypropyltrimethoxysilane (CAS No.: 2530- 83-8), N,N-[bis(3-trimethoxysilyl)propyl]ethylenediamine (CAS No.: 68845-16-9), wherein particularly in each case the adhesion promotor is deposited from acetic acid ethanolic solution (e.g. 0.1% - 5% alkoxysilane content) by dipping.

[0036] Furthermore, in an embodiment of the method, prior to applying the adhesion promoter, the surface of the portion of the housing is at least one of: cleaned, acid-cleaned, wet-chemically oxidized, laser-structured.

[0037] According to a further embodiment of the method, the potting material is an epoxy resin (e.g. EPO-TEK 301, Epoxonic EX3635, all biocompatible, cold-curing epoxy resins based on BADGE / TMD are possible here). Furthermore, according to an embodiment of the method the second connecting member is a rail extending in an axial direction, and wherein the first connecting member of the header body is a groove, wherein the rail and the groove are brought into engagement by inserting the rail into the groove in the axial direction, wherein the rail and the groove are formed such that the header body is pressed against the first portion of the housing in a direction orthogonal to the axial direction upon insertion of the rail into the groove.

[0038] Furthermore, according to an embodiment of the method the first portion of the housing is formed by the flange. In an embodiment of the method, the flange forms a lid of the housing. Furthermore, in an embodiment of the method, the first portion, particularly the lid, comprises a circumferential edge that is welded, particularly laser-welded, to a circumferential edge of a second portion the housing, particularly formed as a beaker or can, after forming of the header. The second housing portion accommodates components of the implantable medical device such as a battery and / or an electronics module.

[0039] Particularly, the first connecting member is integrally formed with the header body, particularly upon said injection molding.

[0040] In an embodiment, the second connecting member may also be connected, particularly integrally connected, to the housing or the first housing portion, respectively. Here, the first portion of the housing may be a portion of the housing to which the feedthrough is connected via its flange, or particularly the first housing portion is substantially formed by the flange, respectively. In one embodiment, the header is formed on the housing and flange after the housing has been formed and hermetically sealed. In an alternative embodiment, the header is formed on the first housing portion, then the first housing portion, e.g., in form of a lid, is hermetically sealed to the second housing portion, e.g. in form of a beaker or can, after components of the medical device, such as a battery and / or an electronics module, have been placed in the second housing portion.

[0041] The method according to the present invention may be further characterized by the features and embodiments described above in conjunction with the implantable medical device and vice versa. Particularly, in the method according to the present invention a third and a fourth connecting member as described herein may also be used to mount the header body to the housing.

[0042] The present invention may be applied to a variety of different implantable medical devices. Particularly, the implantable medical device is one of: a pacemaker, a cardiac pacemaker, a cardioverter defibrillator, cardiac monitor or neurostimulator.

[0043] In the following, embodiments of the aspects of the present invention as well as further features and advantages of the present invention shall be described with reference to the Figures, wherein

[0044] Fig. 1 shows an exploded view of an embodiment of an implantable medical device according to the present invention having a header body connected via at least a first and a second connecting member to a housing of the device,

[0045] Fig. 2 shows a detail of the second connecting member of implantable medical device of Fig. 1

[0046] Fig. 3 shows a different view of the detail shown in Fig. 2,

[0047] Fig. 4 shows a further view of the second connecting member shown in Figs. 1 to 3 comprising an inclined head portion for pressing the header body towards the housing,

[0048] Fig. 5 shows a detail of the first connecting member in form of a groove formed in the header body of the implantable medical device of Fig. 1

[0049] Fig. 6 shows a further detail of the first connecting member in form of a groove formed in the header body of the implantable medical device of Fig. 1,

[0050] Fig. 7 shows the first and the second connecting member brought into engagement for mounting the header to the feedthrough flange / housing of the implantable medical device, Fig. 8 shows a detail of a recess of the header body being mounted to the flange, wherein the recess serves for accommodating the feedthrough pins and an electrically conducting structure (not shown) for contacting the feedthrough pins,

[0051] Fig. 9 shows arranging the electrically conducting structure (outer wiring) in the recess of the header,

[0052] Fig. 10 shows electrically connecting the electrically conducting structure (outer wiring) to at least one connectors of the header and the feedthrough pins,

[0053] Fig. 11 shows filling the recess with a potting material to form the final header and to embed the feedthrough pins and the electrically conducting structure therein,

[0054] Fig. 12 shows the flange with the header formed thereon before being connected to the housing of the implantable medical device, and

[0055] Fig. 13 shows the flange with the header formed thereon connected to the housing of the implantable medical device.

[0056] Fig. 1 shows in conjunction with Figs. 9 to 13 an embodiment of an implantable medical device 1 in according to the present invention, or particularly a header assembly 100 of the implantable medical device 1 according to the invention in different stages of assembly (Figs. 1, 9, 10, 11).

[0057] According thereto, the implantable medical device 1 comprises a first housing portion 2a comprising an electrical feedthrough 3 and a second housing portion 2b, particularly formed a can or beaker 2b hermetically joined to the first housing portion 2, wherein the first housing portion 2a and the second housing portion 2b form the housing 2 of the implantable medical device 1 (cf. e.g., Fig. 12). The housing 2, particularly the second housing portion (2b), is configured for accommodating an electrical circuit 5 of the device 1. The electrical feedthrough 3 comprises a plurality of feedthrough pins 30 for providing an electrical connection to the electronics module 5 from outside the housing 2. Furthermore, the feedthrough 3 comprises at least one electrical (e.g., ceramic) insulator 32 connected, particularly brazed, to a flange 31, wherein particularly the feedthrough pins 30 extend through the at least one electrical insulator 32. The flange 31 particularly forms the first housing portion 2a.

[0058] A header body 40 is mounted to the first housing portion 2a (Figs. 9 to 11) , wherein the header body 40 accommodates at least one connector 41 (here e.g. two connectors 41). Particularly, the implant 1 may be a medical device that provides therapy in form of electrical stimulation. In this case, the connectors 41 may be configured to receive a plug of an electrode lead via which therapy may be applied to a patient and / or sensing can be achieved.

[0059] Furthermore, the implantable medical device 1 comprises an electrically conducting structure 42 connecting the at least one connector 41 to at least one feedthrough pin 30 of said plurality of feedthrough pins 30. Particularly, the electrically conducting structure 42 (also denoted as outer wiring) may comprise electrical conductors arranged on a flat carrier.

[0060] Particularly, the header body 40 is an injection molded header body, wherein particularly the header body 40 is injection molded out a thermoplastic polyurethane (TPU).

[0061] For mounting the header body 40 to the housing 2, particularly to the first housing portion 2a, the implantable medical device 1 comprises a first connecting member 400 provided by the header body 40 and a second connecting member 300 connected to the housing 2 (particularly to the first housing portion 2a or a flange 31 of the feedthrough 3, respectively). Preferably, a further pair of connecting members 400, 300, i.e., a third connecting member 400 and a corresponding fourth connecting member 300, is used opposite the first and second connecting members 400, 300 (cf. Figs. 1 and 8).

[0062] Particularly, the first and the second connecting members 400, 300 are configured to engage with each other to mount the header body 40 to the housing 2, particularly to the first housing portion 2a. Likewise, the third and fourth connecting members 400, 300 are configured to engage with each other as well to achieve said mounting of the header body 40 to the housing 2, particularly to the first housing portion 2a.

[0063] Furthermore, the header body 40 comprises a recess 43 for accommodating the electrically conducting structure 42 and the feedthrough pins 30 when the header body 40 is mounted to the housing 2, particularly to the first housing portion 2a, wherein the recess 43 is filled with a potting material 44 so that the electrically conducting structure 42 and the feedthrough pins

[0064] 30 are embedded in the potting material 44 (cf. Fig. 11).

[0065] In the embodiment shown in Fig. 1, the second housing portion 2b does not form the interface to the header body, i.e., the header body 40 is not directly connected to the second housing portion 2b, but via the first housing portion 2a or the intermediary flange 31 of the feedthrough 3, which sits as a lid on the second housing portion 2b of the overall housing (cf. Fig. 12 and 13) and has the second connecting members 300 arranged on its top side. Particularly, the second connecting members 300 may be integrally formed with the flange

[0066] 31 or the first housing portion 2a, respectively. The feedthrough flange 31 or the first housing portion 2a itself may be an MIM component, which allows such complex geometries at low cost. The mounting directi on / movement of the header body 40 is preferably vertical allowing a top-down mounting of the electrically conducting structure 42 into the recess 43 as shown in Fig. 9 without changing the orientation of the header body 40 and flange 31.

[0067] Furthermore, also the header body 40 preferably comprises a further electrical (e.g. ceramic) insulator 33 which is arranged adjacent the feedthrough pins 30 as shown in Fig. 8 once the header body 40 has been mounted to the flange 31 / housing 2 via the connecting members 400, 300. The further insulator 33 prevents the pins 30 from being bent when they are welded to the electrically conducting structure 42.

[0068] As indicated in Figs. 1 to 7, the first and third connecting members 400 of the header body 40 are grooves 400 comprising an L-shaped cross section, respectively. Correspondingly, the second and fourth connecting members 300 are each formed as a rail 300 that is configured to be inserted into the associated groove 400 in an axial direction A of the respective rail 300. Also, the rails 300 comprise an L-shaped cross section, too.

[0069] Particularly, as shown in Figs. 5 and 6, the respective groove 400 comprises an entrance 401 for receiving the associated rail 300 in the axial direction A to achieve engagement between rails 300 and grooves 400. Particularly, an L-shaped cross section S’ of the respective groove 400 at the entrance 401 orthogonal to the axial direction A is larger than an L-shaped cross section S at a first end 304 of the rail 300 orthogonal to the axial direction A (cf. Figs. 2 and Figs. 5 and 6). Furthermore, particularly, the respective rail 300 is configured to be inserted into the associated groove 400 with its first end 304 ahead to engage the first and the second connecting members 400, 300 with each other. This allows the header body 40 to be “threaded in” relatively freely and without contact with the flange (e.g. lid) 31.

[0070] As indicated in Figs. 2 and 3, the L-shaped cross section S of the respective rail 300 is formed by a base portion 301 and a head portion 302 of the respective rail 300, wherein the respective base portion 301 extends in the axial direction A and is integrally connected to the flange 31 of the feedthrough 3, and wherein the respective head portion 302 is (e.g. integrally) connected to the associated base portion 301 and protrudes from an end of the base portion 301 in a direction orthogonal to the axial direction A as shown in Fig. 2 for instance, wherein particularly the respective head portion 302 is inclined with respect to the axial direction A by an angle a that is particularly in the range of about 2° to 3° such that a height of the respective head portion 302 over the flange 31 decreases starting from the first end 304 towards an opposing second end 305 of the respective rail 300 (cf. Fig.3).

[0071] Furthermore, the respective second end 305 of the respective rail 300 forms a stop of the respective rail for the header body 40, wherein - in the vicinity of the respective stop - the respective rail 300 comprises a latching lug 303 configured to engage with a recess 402 of the groove 400 to fix the header body 40 to the flange 31 and hinder it from sliding out of the grooves 40 when the respective rail 300 is fully inserted (up to the stop) in the associated groove 400. Furthermore, the hermetic connection between the two joining partners (header body 40 and first housing portion 2a or flange 31) is particularly achieved by filling a potting material 44 into the recess 43 that accommodates the outer wiring 42 and the pins 30, particularly by means of an automated dispensing of the potting material 44 (cf. Figs. 10 and 11). Particularly, the potting material can be an epoxy resin (e.g. EPO-TEK 301, Epoxonic EX3635, all biocompatible, cold-curing epoxy resins based on BADGE / TMD are possible here) In this process, a section of the outer geometry of the final header is also created.

[0072] The surface 43a of the recess 43 of the header body 40 (formed preferably out of TPU, e.g., Pellethane 2363 75D, Tecothane TT1075DM, Isoplast 2530-E or Elasthane 75D NW) is preferably oxidized by means of an atmospheric pressure plasma before the assembly and potting process. This can be done, for example, by meandering plasma treatment (Plasmatreat Openair-Plasma®). Exemplarily, the following process parameters may used:

[0073] The activated surface 43a is stable over a period of at least 15 days.

[0074] The surface of the joining partner made of titanium or a titanium alloy, e.g., a surface 3 lb of the flange 31 (e.g., titanium Grade 4, ASTM B 265-00, or metal -injection-molded titanium MIM-Ti-400 ISO 22068 ) may be cleaned, acid-cleaned, wet-chemically oxidized or, in particular, laser-structured. In addition, the surface can be pretreated with adhesion promoters from the alkoxysilane class (e.g. 3-glycidoxypropyltrimethoxysilane, CAS No.: 2530-83-8 or N,N-[bis(3-trimethoxysilyl)propyl]ethylenediamine, CAS No.: 68845-16-9, in each case deposited from acetic acid ethanolic solution (0.1% - 5% alkoxysilane content) by dipping).

[0075] As indicated in Figs. 12 and 13, the design according to the invention enables a simple and cost-efficient assembly of a medical device. Preferably, the header 10 including a connecter 41 configured to receive an electrode lead is mounted on the first housing portion 2a, e.g., formed as a lid, wherein the first housing portion comprises an electrical feedthrough 3 having a plurality of feedthrough pin 30 configured to electrically connect the connector 41 in header body to electronic components, e.g. a battery and / or an electronic module 5, accommodated in the second housing portion 2a, e.g, formed as a beaker or can. After mounting the header 10 to the first housing portion 2a, the connector 41 is electrically connected to one of the feedthrough pins 30 by an electrically conducting structure (42), whereafter the electrical conducting structure and the feedthrough pins are embedded in a suitable potting material 44, there by effectively rendering the header 10 fluid-tight. This yields in a compact header assembly 100, which may easily be joined, e.g. welded, with the second housing portion 2b, after components of the medical device, such a a battery and / or an electronics module 5, have been placed in the second housing portion. Advantageously, the assembly of the medical device may be performed in parallel, i.e. the assembly of the header / housing assembly and the placing of the components of the medical device in of the second housing portion. If one of the assemblies is faulty due to manufacturing problems, the other assembly may be still used in the assembly of the medical device 1.

[0076] The advantages of the present invention lie in the single-axis assembly of all mechanical components, which allows the device header to be assembled in a cost-effective manner that can be automated.

Claims

Claims1. An implantable medical device (1), comprising: a housing (2) for accommodating an electronics module (5), the housing (2) comprising a first housing portion (2a) and a second housing portion (2b), an electrical feedthrough (3) arranged on the first housing portion (2a), wherein the electrical feedthrough (3) comprises a plurality of feedthrough pins (30) for providing an electrical connection to the electronics module (5), a header (10) comprising a header body (40) and a connector (41) being accommodated by the header body (4), wherein the header (10) is mounted to the first housing portion (2a), and an electrically conducting structure (42) connecting the connector (41) to at least one feedthrough pin (30) of said plurality of feedthrough pins (30), wherein the implantable medical device (1) comprises a first connecting member (400) provided by the header body (40) and a second connecting member (300) connected to the first housing portion (2a), wherein the first and the second connecting members (400, 300) are configured to engage with each other to mount the header body (40) to the first housing portion (2a), and wherein the header body (40) comprises a recess (43) for accommodating the electrically conducting structure (42) and the feedthrough pins (30)2. The implantable medical device (1) according to claim 1, wherein the recess (43) is filled with a potting material (44) so that the electrically conducting structure (42) and the feedthrough pins (30) are embedded in the potting material (44).

3. The implantable medical device according to claim 12, wherein the header body (40) is an injection molded header body (40), and / or wherein the header body (40) is formed out of or comprises a thermoplastic polyurethane (TPU).

4. The implantable medical device according to any one of preceding claims, wherein the electrical feedthrough (3) comprises a flange (31), wherein particularly thefeedthrough (3) further comprises at least one electrical insulator (32) connected to the flange (31), wherein particularly the feedthrough pins (30) extend through the at least one electrical insulator (32), and wherein particularly the flange (31) forms the first housing portion (2a), which comprises a circumferential edge (31a) being welded, particularly laser-welded, to a circumferential edge (21b) of the second housing portion (2b).

5. The implantable medical device according to one of the preceding claims, wherein the second connecting member (300) is a rail extending in an axial direction (A), and wherein the first connecting member (400) of the header body (40) is a groove, wherein particularly the rail (300) comprises an L-shaped cross section (S), and wherein particularly the groove (400) comprises an L-shaped cross section (S’).

6. The implantable medical device according to claim 5, wherein the groove (400) comprises an entrance (401) for receiving the rail (300), wherein particularly an L- shaped cross section (S’) of the groove (400) at the entrance (401) is larger than an L- shaped cross section (S) at a first end (304) of the rail (300), and wherein particularly the rail (300) is configured to be inserted into the groove (400) with the first end (304) ahead to engage the first and the second connecting member (400, 300).

7. The implantable medical device according to claim 6, wherein the L-shaped cross section (S) of the rail (300) is formed by a base portion (301) and a head portion (302) of the rail (300), wherein the base portion (301) extends in the axial direction (A) and is connected to the housing (2), and wherein the head portion (302) is connected to the base portion (301) and protrudes from an end of the base portion (301) in a direction orthogonal to the axial direction (A), wherein particularly the head portion (302) is inclined with respect to the axial direction (A) such that a height of the head portion (302) over the flange (31) and / or housing (2) decreases starting from the first end (304) towards an opposing second end (305) of the rail (300).

8. The implantable medical device according to one of the claims 4 to 6, wherein the rail (300) comprises a latching lug (303) configured to engage with a recess (402) of thegroove (400) to secure the header body (40) to the first housing portion (2a) when the rail (300) is inserted in the groove (400).

9. Method for providing a header (10) on a first portion (2a) of a housing (2) of an implantable medical device (1) the first portion (2a) comprising an electrical feedthrough (3) comprising a plurality of feedthrough pins (30), wherein the method comprises the steps of: providing a header body (40) accommodating a connector (41) and comprising a first connecting member (400), mounting the header body (40) to said first portion (2a) of the housing (2) by bringing the first connecting member (400) of the header body (40) and a second connecting member (300) connected to said first portion (2a) of the housing (2) into engagement to mount the header body (40) to said first portion (2a), wherein the header body (40) comprises a recess (43) for accommodating the plurality of feedthrough pins (30) so that the feedthrough pins (30) are accessible from one side, electrically connecting the connector (41) via an electrically conducting structure (42) to at least one feedthrough pin (30) of an electrical feedthrough (3) comprised by said first portion (2a) of the housing (2), wherein the electrically conducting structure (42) is arranged in said recess (43).

10. The method according to claim 9, further comprising the step of filling the recess (43) of the header body (40) with a potting material (44) for forming the header (10), wherein the electrically conducting structure (42) and the feedthrough pins (30) are embedded in the potting material (44), wherein particularly the potting material (44) is an epoxy resin.

11. The method according to claim 9 or 10, wherein the header body (40) is injection molded, and / or wherein the header body (40) is formed out of or comprises a thermoplastic polyurethane, and / or wherein the portion of the housing is formed out of a titanium alloy.

12. The method according to one of the claims 8 to 10, wherein the potting material (44) contacts a surface portion (43 a) of the header body (40), wherein prior to the filling of the recess (43) with the potting material (44) this surface portion (43a) of the header body (40) is oxidized by means of atmospheric pressure plasma.

13. The method according to one of the claims 100 to 12, wherein the potting material (44) contacts a surface (3 lb) of the first portion (2a) of the housing (2), wherein prior to the filling of the recess (43) with the potting material (44) the surface (31b) of the first portion (2a) of the housing (2) is pretreated with an adhesion promoter, wherein particularly the adhesion promoter is one of:- an alkoxysilane,- 3 -glycidoxypropyltrimethoxy silane,- N,N-[bis(3trimethoxysilyl)propyl]ethylenediamine.

14. The method according to one of the claims 8 to 13, wherein the second connecting member (300) is a rail extending in an axial direction (A), and wherein the first connecting member (400) of the header body (40) is a groove, wherein the rail (300) and the groove (400) are brought into engagement by inserting the rail (300) into the groove (400) in the axial direction (A), wherein the rail (300) and the groove (400) are formed such that the header body (40) is pressed against the first portion (2a) of the housing (2) in a direction orthogonal to the axial direction (A) upon insertion of the rail (300) into the groove (400).

15. The method according to one of the claims 10 to 14, wherein the first portion (2a) of the housing (2) is formed by the flange (31), wherein particularly the flange (31) forms a lid of the housing (2), wherein the first portion (2a) of the housing (2) comprises a circumferential edge (31a) that is welded, particularly laser-welded, to a circumferential edge (21b) of a second portion (2b) of the housing after forming of the header (10).

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