Sleeve-shaped medical implant

Abstract

The invention relates to a medical implant having an electrode arrangement configured as a wound cuff, or cuff electrode, suitable for extravascular or extraneuronal fastening along an intracorporeal vessel or a nerve fibre bundle, and having an electrical feed and output arrangement, available over a longitudinal extent, which electrically connects the cuff electrode to an implantable supply unit designed separately from the cuff electrode, wherein the electrical feed and output arrangement, along a section of its longitudinal extent, is surrounded by an elastic casing which fixedly connects the electrical feed and output arrangement to an intracorporeal tissue region via a fastening means that can be operatively connected to the elastic casing. The invention is characterized in that the elastic casing has a longitudinal extent and a circumferential edge oriented radially about the longitudinal extent, and in that at least one tunnel-like opening contour is arranged at the circumferential edge of the casing, along at least a transverse plane oriented orthogonally to its longitudinal extent, which opening contour is suitable for allowing the fastening means, designed as a medical thread, to pass locally therethrough and has no structural components projecting radially beyond the circumferential edge of the casing.

Description

[0001] Cuff-shaped medical implant

[0002] Technical area

[0003] The invention relates to a medical implant with an electrode arrangement designed as a wound cuff, in short cuff electrode, suitable for extravascular or extraneuronal attachment along an intracorporeal vessel or a nerve fiber bundle, and an electrical supply and discharge arrangement having a longitudinal extension, which electrically connects the cuff electrode to a separately formed, implantable supply unit, wherein the electrical supply and discharge arrangement is surrounded along a section in its longitudinal extension by an elastic sheath, which connects the electrical supply and discharge arrangement to an intracorporeal tissue region in a fixed manner via a fastening means that can be brought into operative connection with the elastic sheath.

[0004] State of the art

[0005] EP 3204 105 B1 discloses a cuff electrode arrangement, also referred to as a cuff electrode, consisting of a flexible, biocompatible, film-like carrier substrate, preferably a polyimide film. A plurality of individual electrodes are arranged on at least one surface of the carrier substrate. The known cuff electrode serves for the spatially resolved detection of neuronal electrical signals and for the selective electrical stimulation of individual nerve fibers running within a nerve fiber bundle. For the purpose of supplying electrical energy and signals, all electrodes of the cuff electrode are connected to electrical leads, which in turn are connected to a supply implant designed separately from the cuff electrode.The supply implant is usually implanted subcutaneously in a body area that is easily accessible surgically, for example in the chest area or near the collarbone, whereas the cuff electrode is applied several centimeters away, preferably along the vagus nerve.

[0006] To ensure the electrical energy and signal transmission between the implantable device and the cuff electrode is as tissue-friendly as possible, the required electrical connecting cable must be selected with the smallest possible cable cross-section and a cable length that can compensate for relative movements between the implantable device and the cuff electrode. Typically, the connecting cable is connected to the implantable device via a detachable, fluid-tight plug connection and to the cuff electrode either via a fixed electrical contact or via a plug connection. Both connection variants are explained in the document DE 102017 209 773 A1.In both cases, a carrier plate, usually made of ceramic material, is used to electrically contact the multitude of electrical conductors arranged on the cuff electrode side with the connecting cables combined to form the electrical connecting cable, on which the multitude of electrical contacts are arranged by means of bonding or soldering connections.

[0007] To protect against moisture or the ingress of intracorporeal water, this contact structure, or at least parts of it, is surrounded by a sheath made of biocompatible, electrically insulating material. In addition to its sealing function, its macroscopic dimensions and shape also allow the surgeon to manually handle the cuff electrode during implantation. The sheath, preferably made of an elastic silicone material, typically has a straight cylindrical or ellipsoidal shape, with a longitudinal extension typically in the range of approximately at least 1 cm and a diameter of a few millimeters. In addition, the sheath serves as a type of mechanical counterbearing for additional attachment of the cuff electrode, which, when implanted, tightly encloses a nerve fiber bundle, preferably the vagus nerve, like a cuff.To avoid shear and especially tensile forces acting directly on the cuff electrode along the connecting cable, which can be caused by body movements, these forces are absorbed by an additional mechanical attachment of the sheath to the immediately surrounding tissue areas or redirected into the surrounding tissue.

[0008] In practice, the additional intracorporeal fixation of the sheath to a tissue area adjacent to the vagus nerve has only proven effective insofar as the attachment of the sheath with the aid of a surgical thread ensures a largely constant relative distance between the sheath and the cuff electrode surrounding the vagus nerve in a cuff-like manner and is thus able to absorb the tensile forces acting along the connecting cable. However, rotational movements of the sheath about its longitudinal axis and thus relative to the cuff electrode fixedly attached to the vagus nerve often occur, which lead to mechanical material stresses, also and in particular within the foil-like carrier substrate of the cuff electrode, which must be reduced or completely eliminated.

[0009] US 2015 / 0343198 A1 discloses a guide anchor for the intracorporeal attachment of an electrical cable that can be passed through the inner lumen of a flexible housing. To secure the cable within the housing, the housing provides a deformable insert that can fix the cable by means of a crimp. Eyelets protruding from the insert are attached to the outside of the housing and serve as holding means for securing the housing to surrounding tissue.

[0010] The publication US 2008 / 172116 A1 describes a cuff electrode arrangement for attachment around a nerve cord and with an electrical lead wire, which has a helical attachment structure for attachment along the lead wire, which can be applied in a looping manner around a vessel or nerve cord. Description of the invention

[0011] The invention is based on the object of developing a medical implant with an electrode arrangement designed as a wound cuff, in short a cuff electrode, suitable for extraversal or extraneuronal fastening along an intracorporeal vessel or a nerve fibre bundle, and with an electrical supply and discharge arrangement having a longitudinal extent which electrically connects the cuff electrode to a separately designed, implantable supply unit, wherein the electrical supply and discharge arrangement is surrounded along a section of its longitudinal extent by an elastic sheath which connects the electrical supply and discharge arrangement to an intracorporeal tissue region in a fixed position via a fastening means which can be brought into operative connection with the elastic sheath, in such a way that rotational movements of the sheath around its longitudinal extent are at least reduced orlimited, but preferably completely excluded.

[0012] The solution to the problem underlying the invention is specified in claim 1 and claim 5. Features that advantageously further develop the inventive concept are the subject of the subclaims and the further description with reference to the exemplary embodiments.

[0013] The medical implant according to the solution with the features of the preamble of claim 1 is characterized in that the elastic sheath has a longitudinal extension and a circumferential edge oriented radially around the longitudinal extension, wherein at least one tunnel-like opening contour is arranged on the circumferential edge of the sheath along at least one cross-sectional plane oriented orthogonally to its longitudinal extension, which opening contour is suitably designed for the local passage of the fastening means designed as a medical thread and has no structural components projecting radially beyond the circumferential edge of the sheath.Preferably, along the circumferential edge in the cross-sectional plane in which the at least one tunnel-like opening contour is arranged, a completely circumferential, preferably V-shaped, groove-like recess is incorporated, along which the medical thread can be brought into direct contact, at least in some areas. The at least one tunnel-like opening contour is preferably delimited radially outwards by a web which locally bridges the groove-like recess and is preferably monolithically connected to the elastic sheath, i.e. consists of the same material as the elastic sheath itself. The surface of the at least one web which locally bridges the groove-shaped recess is flush with the remaining surface of the sheath, so that the surrounding tissue regions are not irritated by any structural components which radially project beyond the at least one tunnel-like opening contour.

[0014] To block or limit the rotation or self-rotation of the elastic sheath around its longitudinal extent, the surgical thread, in the case of a single tunnel-like opening contour, is placed into the groove-shaped recess, forming at least one complete loop. The thread is threaded twice through the tunnel-like opening contour, each time in opposite threading directions. The two thread sections extending from the opening contour serve to fixate the surrounding tissue and, after securing, e.g., by knotting, extend under tension on both sides of the sheath.When the sheath rotates around its longitudinal extent, clamping forces blocking rotation develop at the tunnel-like opening contour and the thread strands extending away from the opening contour on both sides. These clamping forces increase significantly with increasing rotation of the sheath around its longitudinal extent and prevent or block rotation. The proposed measure on the sheath, in conjunction with the surgical thread, is based on the principle of self-locking, whereby clamping forces oriented opposite to the rotational movement develop between the surgical thread subjected to tensile or tensioning force and the at least one tunnel-like opening contour.

[0015] In a further preferred embodiment, two tunnel-like opening contours are arranged along a common cross-sectional plane of the sheath, preferably located in opposing regions along the peripheral edge. In this case, the medical thread is guided through both opening contours in such a way that the medical thread is subjected to a tensile force at least along a contact length a at the peripheral edge of length U, where the following applies to the contact length a: 0.5 U < a < U. Of course, both opening contours can also be arranged at a smaller minimum distance from each other along the peripheral edge.

[0016] To ensure stable attachment of the sheath relative to a surrounding tissue area, in a further embodiment, the sheath has at least one tunnel-like opening contour at two or more axially spaced cross-sectional planes. In this way, the sheath can be attached relative to the cuff electrode and a surrounding tissue area using two medical threads.

[0017] In a further alternative medical implant according to the invention, according to the features of the preamble of claim 1, at least one fastening contour is provided on the peripheral edge of the elastic sheath, preferably in the form of a structural local elevation above the peripheral edge and / or a local depression opposite the peripheral edge. Furthermore, a separate joining means designed for the sheath is provided, which has a joining contour that is contoured counter to the fastening structure and also has at least one through-opening for passing through the fastening means designed as a medical thread.In the state of the fixed connection of the elastic sheath to an intracorporeal tissue area, the medical thread is guided and arranged through the at least one through-opening of the joining means and subjected to tensile force along the peripheral edge of the elastic sheath, so that the joining means is joined to the fastening contour of the sheath under the action of a force.

[0018] Preferably, the joining means is plate-shaped and has at least one through-opening through which the medical thread can be passed and, under the exertion of a tensile force, the joining means is fixedly inserted into the

[0019] Attachment contour of the casing. A possible specific embodiment and its function are explained in more detail below with reference to the figures.

[0020] Brief description of the invention

[0021] The invention is described below, without limiting the general inventive concept, using exemplary embodiments with reference to the drawings. They show:

[0022] Fig. 1a, b schematic representation of a known sheath and a sheath designed according to the solution,

[0023] Fig. 2a Cross section through the casing according to Figure 1 b,

[0024] Fig. 2b Cross section through an alternative embodiment of the

[0025] Sheathing with only a single tunnel-like fastening structure,

[0026] Fig. 3a, b Cross sections through embodiments of the casing with alternatively tunnel-like fastening structures, as well as

[0027] Fig. 4a, b alternative embodiment for forming a casing according to the invention with a separate joining agent. Ways of implementing the invention, industrial applicability

[0028] Figure 1a schematically shows a cuff electrode 1 known per se, which is designed as a wound cuff and has a plurality of surface electrodes 1e arranged on the inner side of the cylinder jacket of the wound cuff for directly contacting a nerve fiber bundle (not shown), for example the vagus nerve. The plurality of electrodes 1e is each connected to separate electrical lines 1e1 running within the foil-like carrier substrate of the cuff electrode 1, which lead to a plate-shaped connecting structure 2 for further contacting and are connected to electrical contact surfaces 3 arranged on its surface. At each electrical contact surface 3, an electrical supply or discharge line 5 is contacted via a bond or solder connection, the plurality of which is combined to form a connecting cable 4, which leads to a separate, not shown, supply implant for further contacting.

[0029] For protection against moisture and for the purpose of mechanically stabilizing the cuff electrode 1 during intracorporeal attachment and for its handling, a sheath 6 made of elastic, biocompatible material, preferably silicone, is arranged in the area of ​​the connecting structure 2. In the case shown, this sheath 6 is ellipsoidal in shape. It should be noted at this point that the size representation chosen in Figure 1a between the cuff electrode 1 and the sheath 6 is not realistic, but merely serves to improve the visual representation. The sheath 6 has a circumferential groove-shaped recess 7 on its surface, into which a surgical thread 8 can be placed, which serves to fix the sheath 6 to an immediately surrounding tissue area 11.

[0030] Figure 1b shows a further development of the casing 6 illustrated in Figure 1a, in such a way that a tunnel-like opening contour 9 is arranged along the preferably V-shaped groove-like recess 7, which is formed by a web 10 that locally bridges the groove-like recess 7. The further groove-like recess 7, shown in dashed lines in Figure 1b, with the similarly provided tunnel-like opening contour 10, is intended to illustrate a preferred further development of the casing 6.

[0031] Figure 2a shows a cross-section through the sheath 6 as shown in Figure 1b in the region of the groove-shaped recess 7, whereby the radially inner conductor structures have been omitted. Two tunnel-like opening contours 9 are arranged in two opposite regions of the circumferential groove-shaped recess 7, each of which is radially delimited to the outside by a web 10 that adjoins the remaining peripheral edge of the sheath 6.

[0032] A surgical thread 8 is used to fasten the sheath 6 to an immediately adjacent, intracorporeal tissue area 11. The thread is threaded through both tunnel-like opening contours 9 in the manner shown in Figure 2a and comes to rest halfway on the peripheral edge of the V-shaped groove-like recess 7. The surgical thread 8 is fixed within the tissue area 11, preferably knotted, so that the thread 8 applies tension and presses the sheath 6 stationary against the tissue area 11. The surgical thread 8 comes into contact with a boundary edge 12 of the web 10. During rotational movements of the sheath 6 about its longitudinal extent, clamping forces occurring at the boundary edges 12 in interaction with the surgical thread 8 ensure that the rotational movement is blocked or prevented.

[0033] Figure 2b shows a cross-sectional view through an embodiment of the sheath 6 along the groove-shaped recess 7 with only one tunnel-like opening contour 9. In order to prevent rotational movements of the sheath 6 around its longitudinal extent, in this case the surgical thread 8 is wound around the groove-shaped recess 7 to form at least one complete thread loop. The thread end regions emerging from the tunnel-shaped opening contour 9 on both sides, which are subsequently knotted for fixation within the tissue region 11, come into contact with the two boundary edges 12 of the web 10. In this case too, during rotational movements of the sheath 6 around its longitudinal extent, clamping forces occurring due to the interaction of the boundary edges 12 and the surgical thread 8, which runs subjected to this tension force, can prevent or prevent the rotation of the sheath 6.to block.

[0034] Figure 3a shows a schematic cross-sectional view through an alternative embodiment of a sheath 6 designed according to the solution, which provides two curved, tunnel-like opening contours 9 through which a surgical thread 8 is threaded and fixed in the surrounding tissue 11 for its attachment. As an alternative to the curved design of the tunnel-like opening contours 9, it is also conceivable to design them in a straight line, as shown in Figure 3b, in which the sheath 6 has only a single, tunnel-like opening contour 9 through which the surgical thread 8 is threaded and knotted to the surrounding tissue region 11. Preferably, the tunnel-like opening contour 9 has a maximum opening width w of 0.1 mm < w < 1 mm and a tunnel length I of 0.5 mm < I < 2 mm.

[0035] Figures 4a and b show, in side view and in cross-sectional view, a casing 6 having four recesses 13 in the form of blind holes on its peripheral edge, which serve as a fastening contour 14, into which a separate joining means 15 with a joining contour 16 configured to counter-contour the fastening contour 14 can be inserted. The joining contour 16 is configured in the form of four nubs 17.

[0036] The joining means 15 furthermore has a central opening 18 through which a surgical thread 8 is threaded, forming a loop that completely encompasses the sheath 6, the thread ends 19 of which are knotted and fixed in an immediately adjacent tissue area 11. The geometric design of the joining contour 16, on the one hand, and the fastening contour 14, which is contoured to match it, on the other hand, are designed in accordance with a form-fitting connection that is formed and are otherwise not subject to any design specifications.

[0037] List of reference symbols

[0038] Cuff electrode e surface electrodes el electrical conduction

[0039] Connection structure

[0040] Bond / solder connection

[0041] Connecting cable electrical supply and discharge

[0042] Sheathing groove-shaped recess

[0043] Fastening means, surgical thread, tunnel-like opening contour 0 Bars 1 Tissue area 2 Boundary edge 3 Recess 4 Fastening contour 5 Joining means 6 Joining contour 7 Studs 8 Opening 9 Thread end

Claims

Patent claims 1. A medical implant comprising an electrode arrangement configured as a wound cuff, in short a cuff electrode (1), suitable for extravascular or extraneuronal attachment along an intracorporeal vessel or a nerve fiber bundle, and an electrical supply and discharge arrangement having a longitudinal extension, which electrically connects the cuff electrode (1) to an implantable supply unit configured separately from the cuff electrode (1), wherein the electrical supply and discharge arrangement is surrounded along a section of its longitudinal extension by an elastic sheath (6), which connects the electrical supply and discharge arrangement to an intracorporeal tissue region (11) in a fixed manner via a fastening means (8) that can be brought into operative connection with the elastic sheath (6), characterized in thatthat the elastic sheath (6) has a longitudinal extension and a circumferential edge oriented radially around the longitudinal extension, that at least one tunnel-like opening contour (9) is arranged on the circumferential edge of the sheath (6) along at least one cross-sectional plane oriented orthogonally to its longitudinal extension, which opening contour is suitable for the local passage of the fastening means designed as a medical thread (8) and has no structural components projecting radially beyond the circumferential edge of the sheath.

2. Medical implant according to claim 1, characterized in that a groove-shaped recess (7) is provided along the peripheral edge in the cross-sectional plane in which the at least one tunnel-like opening contour (9) is arranged, and in that the at least one tunnel-like opening contour (9) is formed by a web (10) which locally bridges the groove-shaped recess (7).

3. Medical implant according to claim 1 or 2, characterized in that the medical thread (8) is guided through the at least one tunnel-like opening contour (10) in such a way that the medical thread (8) bears against the circumferential edge with the length U along a contact length a, subjected to a tensile force, wherein the following applies to a: 0.5 U < a < U.

4. Medical implant according to one of claims 1 to 3, characterized in that the at least one tunnel-like opening contour (10) each has a maximum opening width w with 0.1 mm < w < 1 mm and a tunnel length I with 0.5 mm < I < 2 mm.

5. Medical implant according to the preamble of claim 1, characterized in that the elastic sheath (6) has a longitudinal extension and a circumferential edge oriented radially around the longitudinal extension, that at least one fastening contour (14) is provided on the circumferential edge, that a joining means (15) separate from the sheath (6) is provided with a joining contour (17) configured to counter-contour the fastening contour (14), that the joining means (15) has at least one through-opening (18) for passing through the fastening means configured as a medical thread (8), and that in the state of the stationary connection of the elastic sheath (6) to the intracorporeal tissue region (11), the medical thread (8) is guided through the at least one through-opening (18) of the joining means (15) and is subjected to tensile force along the circumferential edge of the elastic sheath (6) is applied,that the joining means (15) is joined to the fastening contour (14) of the casing (6) under force., 6. Medical implant according to claim 5, characterized in that the fastening contour (14) is designed in the manner of a structural local elevation over the peripheral edge and / or a local depression opposite the peripheral edge.

7. Medical implant according to claim 5 or 6, characterized in that the joining means (15) is plate-shaped and has at least one through-opening (18).

8. Medical implant according to one of claims 1 to 7, characterized in that the casing (6) is designed in the form of an ellipsoid.

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