Medical implant in the form of a wrap sleeve

Abstract

The invention relates to a medical implant in the form of a wrap sleeve for arranging about a nerve fiber bundle, comprising a flat biocompatible film-like substrate with at least one first flat substrate section that can be converted into a hollow cylindrical shape by means of a winding process in a winding direction, which is specified by a set shape that is inherent to the material, about a spatial axis and has a first flat substrate section end which rests against a first surface of the first flat substrate section in the wound state, said surface being oriented so as to face an area radially enclosed by the wound first flat substrate section, and a second flat substrate section end, which lies opposite the first flat substrate section end and is arranged laterally to a second surface of the first flat substrate section, said second surface facing away from the first surface, in the wound state, said second surface being oriented so as to face away from the area radially enclosed by the wound first flat substrate section. At least one region of the first flat substrate section end is monolithically connected to a second flat substrate section which rests against the second surface of the first flat substrate section in the wound state. The invention is characterized in that each of the first and second flat substrate sections has the set shape which is inherent to the material with a respective winding direction which is oriented opposite the first flat substrate section end.

Description

[0001] Medical implant in the form of a wrap cuff

[0002] Technical area

[0003] The invention relates to a medical implant in the form of a wound cuff for placement around a nerve fiber bundle, comprising a film-like, biocompatible surface substrate having at least a first surface substrate section which can be converted into a hollow cylinder-like shape by winding around a spatial axis with a winding direction predetermined by a material-inherent shape impression, having a first surface substrate section end which, in the wound state, abuts a first surface of the first surface substrate section, which is oriented toward a space radially enclosed by the wound first surface substrate section, and having a second surface substrate section end opposite the first surface substrate section end, which, in the wound state, is arranged on the side of a second surface of the first surface substrate section facing away from the first surface,which is oriented away from the space radially enclosed by the wound first surface substrate section.,

[0004] State of the art

[0005] For the purpose of intracorporeal application of electrical stimulation signals along a nerve fiber bundle, so-called wound cuffs, also referred to as cuff electrodes, are used. A particularly preferred cuff electrode is disclosed in the document EP 3 204 105 B1. Cuff electrodes have a film-like, biocompatible surface substrate capable of locally wrapping around a nerve fiber bundle, on the surface of which an electrode arrangement is attached for the application of electrical signals, which is brought into direct surface contact with the epineurium of a nerve fiber bundle. For this purpose, the film-like surface substrate provides an intrinsically impressed mechanical tension such that the otherwise preferably rectangular, film-like surface substrate can be wound or unwound independently around a winding axis in an otherwise force-free state to form a straight hollow cylinder.is capable of rolling up. Usually, the foil-like surface substrate is flat and rectangular in shape, at least in the area of ​​the material-inherent prestress, with a free surface substrate side edge that is guided at least once, preferably multiple times, around a winding axis, wherein the foil-like carrier substrate forms multiple, loosely adjacent, hollow-cylindrical surface substrate windings. In the area of ​​the surface of the surface substrate directly facing the volume enclosed by the winding sleeve, the electrode arrangement is attached in order to directly contact the surface of the epineurum of the nerve fiber bundle when implanted and applied locally around a nerve fiber bundle. To support or improve the surface contact orThe contact pressure between the electrode arrangement and the nerve fiber bundle is achieved by multiple wrapping of the surface substrate around the nerve fiber bundle, whereby the mechanical hold on the outer circumference of the nerve fiber bundle is improved with increasing number of wrappings.

[0006] The radially outermost winding of the flat substrate merges integrally into a mechanically non-prestressed, i.e. otherwise flat, flat substrate section to which an electrical contact arrangement is usually attached, via which electrical supply and discharge lines connected to the electrode arrangement can be connected via a corresponding conductor structure to an implantable electrical supply unit in which means for the electrical energy supply as well as for the control and operation of the cuff electrode are accommodated.

[0007] The current practice for implanting a cuff electrode requires a high degree of skill and steady hands from the surgeon, especially since the cuff electrode, in its normal state, i.e., when not subjected to force, automatically assumes the hollow cylindrical coiled state described above. To convert the cuff electrode into an uncoiled or opened state for application to the outer circumference of a nerve fiber bundle, it is necessary, on the one hand, to pick up the cuff electrode at its mechanically unstressed, flat surface area, preferably using tweezers, and, on the other hand, to stretch the cuff-like coiled surface substrate area flatly under force, counter to the winding effect inherent in the material, so that the film-like surface substrate assumes a largely uncoiled, flat shape.

[0008] A wire-like instrument bent into an "L" shape is suitable for this purpose. The short L-shaped leg of the instrument is guided completely through the rolled-up cuff electrode on one side along the winding axis. Subsequently, by applying a controlled pulling force along the longer L-shaped leg of the instrument and with appropriate counter-holding using tweezers, the wrapped cuff is transformed into an elongated, i.e., stretched, shape.

[0009] The procedure described above must be carried out by the surgeon with both hands and requires maximum concentration both for the placement of the cuff electrode along the nerve fiber bundle and for the process of developing the cuff electrode, especially since even a slightly too wide tension of the winding surface substrate leads to the instrument slipping or detaching from the stretched surface substrate, whereby the surface substrate spontaneously returns to the rolled-up or wound-up state.

[0010] Particularly under real-life surgical conditions, where space, visibility, and time are limited, the surgeon requires a high level of technical and surgical experience. In addition, failed attempts or incorrect application of the cuff electrode along a nerve fiber bundle represent avoidable stress for the patient.

[0011] The document DE 10 2018 207 709 A1 discloses a device for the extraneuronal attachment of a medical implant with a biocompatible flat substrate. The substrate comprises a first substrate section designed in the manner of a wound sleeve, which has a free section end which, by winding the first substrate section around a spatial axis, is loosely covered radially in at least one layer by the wound first substrate section, and a second substrate section which is integrally connected to the first substrate section and is not wound around the spatial axis and which can be connected directly or indirectly to a connecting structure leading away from the medical implant. In the region of the section end, at least one means is arranged which, when the first substrate section is wound around the spatial axis, forms a joining connection with the first substrate section or with the second substrate section.

[0012] Description of the invention

[0013] The invention is based on the object of providing a medical implant in the form of a wound cuff for arrangement around a nerve fiber bundle, with a film-like, biocompatible surface substrate, which has at least a first surface substrate section, which can be converted into a hollow cylinder-like shape by winding with a winding direction predetermined by a material-inherent shape impression around a spatial axis, and a first surface substrate section end, which in the wound state rests against a first surface of the first surface substrate section, which is oriented facing a space radially enclosed by the wound first surface substrate section, as well as a second surface substrate section end opposite the first surface substrate section end, which in the wound state is arranged on the side of a second surface of the first surface substrate section facing away from the first surface,The aim is to further develop the wound cuff, which is oriented away from the space radially enclosed by the wound first surface substrate section, in such a way that handling for a surgeon during implantation and application of the wound cuff around a nerve fiber bundle is significantly facilitated, and mishandling and incorrect placement can be largely eliminated. Furthermore, it should be possible to handle the wound cuff safely and professionally under surgically confined spatial conditions.

[0014] The solution to the problem underlying the invention is defined in claim 1. Features that advantageously further develop the inventive concept are the subject of the dependent claims and the further description, in particular with reference to the figures.

[0015] According to the solution, a medical implant in the form of a winding cuff for arranging around a nerve fiber bundle with the features of the preamble of claim 1 is characterized in that the first and second surface substrate sections each have a material-inherent shape impression, each with a winding direction oriented opposite to the first surface substrate section end.

[0016] Preferably, the first end of the flat substrate section is formed by folding the film-like, biocompatible flat substrate in the manner of a folded edge, so that the first and second flat substrate sections lie directly against each other. It is not necessary, but preferably, for both flat substrate sections to be identical or of the same size in shape and size, so that they lie completely against each other in the wound state.

[0017] It is also conceivable for the second surface substrate section to be smaller in area than the first surface substrate section, for example in a strip-shaped configuration, which locally projects beyond at least the second surface substrate section end in order to obtain unhindered access to the second surface substrate section, for example by means of a gripping instrument, for example tweezers.

[0018] The first and second flat substrate sections each have a material-inherent shape impression such that both flat substrate sections connected via the common fold edge independently roll helically around a common winding axis, wherein the common fold edge, which corresponds to the first flat substrate section end, is arranged inwardly of the hollow cylindrical winding shape. If both flat substrate sections are pulled apart in opposite directions at their ends opposite the fold edge, for example with the aid of two tweezers, it becomes clear that both flat substrate sections, which are connected via the first flat substrate section end or the fold edge and are arranged largely opposite one another in the extended state, have a material-inherent shape impression that has an oppositely oriented winding direction.

[0019] In order to ensure safe and reliable handling of the medical implant for the purpose of implantation or application along a nerve fiber bundle and, moreover, to facilitate this, the second surface substrate section end of the first surface substrate section is monolithically connected along at least one section to a fourth surface substrate section which projects beyond the first surface substrate section at least in regions, in the manner of a tab, tongue or flag.

[0020] The second surface substrate section has a third surface substrate section end opposite the first surface substrate section end designed as a folded edge, which in the wound state projects beyond the second surface substrate section end at least in regions, or along which a fifth surface substrate section is monolithically connected, which projects beyond the second surface substrate section at least in regions, in the manner of a tab, tongue or flag.

[0021] At the fourth and fifth tab-like surface substrate sections, respectively, the medical implant can be grasped with a gripping instrument, e.g., tweezers, or manually. It can be transferred from the wound state by diametrically pulling it apart into an open state, in which the medical implant can be conveniently applied locally around a nerve fiber bundle. Brief description of the invention

[0022] The invention is described below, without limiting the general inventive concept, using exemplary embodiments with reference to the drawings. They show:

[0023] Fig. 1a, b Comparison of a cuff electrode arrangement according to the state of the art, see a), with a cuff electrode arrangement according to the solution, see b) and

[0024] Fig. 2 Sequence images for the production of the solution-based cuff-

[0025] Electrode and attachment of the cuff electrode along a nerve fiber bundle.

[0026] Ways of implementing the invention, industrial applicability

[0027] Figure 1a shows a cuff electrode known per se with a first flat substrate section 1 consisting of a foil-like, biocompatible flat substrate, which, due to a material-inherent shape impression with a predetermined winding direction WS around a spatial axis R, automatically assumes a hollow cylindrical wound shape. In this wound state, the first flat substrate section 1, with its surface 3 facing the plane of the drawing, radially encloses a cylindrical space 4 from the outside, through which, in the implanted state of the cuff electrode, a nerve fiber bundle protrudes, filling the space. On the surface 3 of the first flat substrate section 1, in the region of the first winding radially enclosing the space 4, an electrode arrangement 5 is attached, which is capable of coming into direct contact with the epineurum of a nerve fiber bundle. The first

[0028] The flat substrate section 1 is preferably rectangular in shape and has a first flat substrate section end 2, which, as shown in Figure 1a, rests loosely on the surface 3 of the flat substrate 1 in the wound state. The cuff electrode has at least one complete winding in the wound state; preferably, multiple flat substrate windings are formed in order to obtain a long-term stable winding shape of the cuff electrode.

[0029] For the sake of completeness, it should be noted that the electrode arrangement 5 is contacted via electrical supply and discharge lines (not shown in detail) running within the flat substrate, which are connected via a further connection structure 6 connected to the first flat substrate section 1 to an implantable supply unit (not shown in detail), which is not the subject of the application.

[0030] In contrast, Figure 1b shows a preferred embodiment of a medical implant designed according to the invention in the form of a wound cuff or cuff electrode which, in addition to the known cuff electrode illustrated in Figure 1a, is monolithically connected along its first surface substrate section 2 to a further, so-called second surface substrate section 7 which, in the wound state, lies loosely against the surface 8 facing away from the surface 3 shown in Figure 1b.

[0031] In the case shown in Figure 1b, the second surface substrate section 7 is formed uniformly and of the same dimensions as the first surface substrate section 1 and, together with the latter, radially encloses the inner space 4, wherein the electrode arrangement 5 applied to the first surface substrate section 1 remains unchanged facing the inner space 4.

[0032] The first and second flat substrate sections 1, 7 each have a second and third flat substrate section end 9, 10 opposite the first flat substrate section end 2, which are each monolithically connected to a tongue- or flag-like flat substrate extension 11, 12. The flat substrate extensions 11, 12 serve to simplify and secure handling of the cuff electrode, preferably with the aid of a gripping instrument, for example, with the aid of tweezers. Figures 2a to g illustrate the manufacture and handling of the cuff electrode for the purpose of application around a nerve fiber bundle.

[0033] Figure 2a shows a film-like, biocompatible surface substrate that is flat and rectangular in shape. The upper half of the surface substrate in the illustration according to Figure 2a represents the first surface substrate section 1, on whose surface 3 the electrode arrangement 10 is attached. The lower half, which is integrally connected to the first surface substrate section 1 and corresponds to the second surface substrate section 7, is, as in the case shown, the same size and dimensions as the first surface substrate section 1. Both surface substrate sections 1, 7 provide the above-described tab- or tongue-shaped surface substrate extensions 11, 12 at their respective surface substrate section ends 9, 10.The second surface substrate section 7 can also be designed to be smaller in area; it is essential that the second surface substrate section 7 locally projects beyond the first surface substrate section 1 in the wound state at its surface substrate section end 9.

[0034] For the purpose of electrical energy and signal transmission and supply of the electrode arrangement 10, a connection structure 6 is additionally attached to the first surface substrate section 1, which is integrated in the surface substrate and leads to an implantable supply unit (not shown in detail).

[0035] The first and second surface substrate sections 1, 7 are monolithically connected to one another via the so-called first surface substrate section end 2, which, as will be shown below, corresponds to a kink or fold edge.

[0036] Thus, in Figure 2b, the second flat substrate section 7 is bent or folded backwards along and around the first flat substrate section end 2, see arrow representation in Figure 2b, so that the second flat substrate section 7 comes to rest flatly on the first flat substrate section 1 on the rear side of the electrode arrangement 10, see Figure 2c. Next, the two first and second flat substrate sections 1, 7, which lie flat against one another, are wound around a spatial axis, starting with their common first flat substrate section end, which is designed as a folded edge, in such a way that the electrode arrangement 10 remains oriented facing the space radially encompassing during winding. The wound state is shown in Figure 2d. In this representation, the entire surface area of ​​the first and second flat substrate sections 1, 7 is rolled up in the form of a two-layer cylinder.In order to imprint the cylindrical shape inherently into the foil-like biocompatible surface substrate, the wound cuff electrode is subjected to a tempering process according to the shape illustrated in Figure 2d.

[0037] For the purpose of handling and applying the cuff electrode along a nerve fiber bundle 13 (see Figure 2e), the cuff electrode is transferred into a stretched or elongated state by a surgeon grasping the surface substrate extensions 11, 12 using a suitable gripping instrument 14, 15, for example, forceps, and transferring the cuff electrode into a stretched or extended state, as shown in Figure 2e. In this stretched or opened state, the surgeon is able to apply the cuff electrode to a defined surface area of ​​a nerve fiber bundle 13. By reducing the tensile forces acting on the cuff electrode, the cuff electrode wraps itself around the nerve fiber bundle 13 (see Figure 2f). The independent rolling process of the cuff electrode around the nerve fiber bundle 13 can be controlled in a controlled manner by the surgeon reducing the pulling or holding forces using the forceps 14, 15.

[0038] Once the cuff electrode is correctly positioned along the nerve fiber bundle 13, the cuff electrode remains stable over the long term due to the inherent restoring forces inherent in the material of the double-layer cuff electrode. This state is illustrated in Figure 2g.

[0039] Surface substrate first surface substrate end

[0040] surface

[0041] Space

[0042] Electrode arrangement

[0043] Connection structure second surface substrate section opposite surface second surface substrate section end third surface substrate section end

[0044] Surface substrate extension

[0045] Surface substrate extension

[0046] Nerve fiber bundle, 15 gripping instrument, e.g. forceps

Claims

Patent claims 1. A medical implant in the form of a wound cuff for placement around a nerve fiber bundle (N), comprising a film-like, biocompatible surface substrate having at least a first surface substrate section (1) which can be converted into a hollow-cylindrical shape by winding around a spatial axis (R) with a winding direction (WS) predetermined by a material-inherent shape impression, having a first surface substrate section end (2) which, in the wound state, abuts a first surface (3) of the first surface substrate section (1) which is oriented toward a space (4) radially enclosed by the wound first surface substrate section (1), and having a second surface substrate section end (9) opposite the first surface substrate section end (2) which, in the wound state, is arranged on the side of a second surface (8) of the first surface substrate section (1) facing away from the first surface (3).which is oriented away from the space (4) radially enclosed by the wound first surface substrate section (1), wherein at least one region of the first surface substrate section end (2) is monolithically connected to a second surface substrate section (7) which, in the wound state, rests against the second surface (6) of the first surface substrate section (1), characterized in that the first and second surface substrate sections (1, 7) each have a material-inherent shaped impression, each with a winding direction (WS) oriented opposite to the first surface substrate section end (2).

2. Medical implant according to claim 1, characterized in that the first surface substrate section end (2) is formed by folding the film-like, biocompatible surface substrate in the manner of a folded edge.

3. Medical implant according to claim 1 or 2, characterized in that the second surface substrate section (7) has a third surface substrate section end (10) which, in the wound state, projects at least partially beyond the first surface substrate section (1) along its second surface substrate section end (9).

4. Medical implant according to one of claims 1 to 3, characterized in that the second surface substrate section end (9) of the first surface substrate section (1) is monolithically connected along at least one section to a surface substrate extension (11) which projects beyond the first surface substrate section (1) at least in regions, and in that the third surface substrate section end (10) of the second surface substrate section (7) is monolithically connected along at least one section to a further surface substrate extension (12) which projects beyond the first surface substrate section (1) at least in regions.

5. Medical implant according to claim 4, characterized in that the surface substrate extensions are each designed in the form of a tab.

6. Medical implant according to one of claims 1 to 5, characterized in that the wound cuff is designed as a cuff-electrode cuff, with an electrode arrangement (5) arranged on and within the first surface substrate section (1), which has at least one electrode contact surface freely accessible on the first surface (3).

7. Medical implant according to one of claims 1 to 6, characterized in that the film-like, biocompatible Surface substrate and the material-inherent shape impression in the first and second surface substrate sections (1, 7) are selected such that, by manually performed application, the medical implant can be autonomously transferred from an elongated state, in which the first and second surface substrate sections (1, 7) are stretched along a plane in opposite directions under the action of tensile force, into the wound state by terminating the application of tensile force.

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