Medical implant

Abstract

The invention relates to a medical implant having a film-like flexible surface substrate in which a material-inherent, shape-defined restoring force is impressed, said restoring force shaping the film-like flexible surface substrate into a straight cylindrical wound sleeve without external forces, after the complete first winding layer is formed, the first winding layer is wound at least partially by at least one further winding layer. The invention is characterized in that at least one locally defined pattern of a first type is applied in the region of the first winding layer and at least one locally defined pattern of a second type is applied in the region of the at least one further winding layer on the film-like flexible surface substrate, the at least one locally defined pattern of the first type and of the second type is applied to the film-like flexible surface substrate such that they are visually perceivable from the radially outside.

Description

Technical Field

[0001] The present invention relates to a medical implant having a thin-film flexible substrate in which a material-inherent, shape-defined restoring force is imprinted, the restoring force being capable of shaping the thin-film flexible substrate into a straight cylindrical wrapping sleeve without the application of external force, such that after a complete first wrapping layer is formed, the first wrapping layer is at least partially wrapped by at least one additional wrapping layer. Background Technology

[0002] Document EP 3 204 105 B1 discloses a wound sleeve electrode device, also known as a sleeve electrode, which is composed of a flexible, biocompatible thin-film carrier substrate, preferably made of polyimide film. Multiple individual electrodes are arranged on at least one surface of the carrier substrate. The inherent resilience of the material is imprinted in the thin-film carrier substrate through a heat treatment process, allowing the carrier substrate to autonomously and without external force roll into a straight cylindrical sleeve shape. This property is used to apply the sleeve electrode around a nerve fiber bundle. Known sleeve electrodes are used for spatially resolved detection of neuronal electrical signals and for selective electrical stimulation of individual nerve fibers extending within a nerve fiber bundle.

[0003] In order to ensure the long-term and reliable function of the sleeve electrode in the implanted state, multiple electrodes arranged on a thin film carrier substrate need to contact the epineurium of the nerve fiber bundle (preferably the vagus nerve) with the most uniform contact pressure and in a precisely preset spatial arrangement.

[0004] Therefore, the thin-film carrier substrate of the cuff electrode must be designed and customized according to the shape and size of the vagus nerve to generate the most uniform contact pressure possible on the vagus nerve surface during implantation. This contact pressure serves both for secure fixation and for proper electrical contact of the multiple electrodes on the epineurium of the vagus nerve. Ideally, the cuff electrode, formed as a wrapped sleeve, presents a straight cylindrical shape during implantation, wherein the carrier film autonomously forms, preferably, multiple wrapping layers around bundles of nerve fibers using its inherent material resilience. These wrapping layers overlap and loosely adhere to each other. Here, the axial boundary edges of each wrapping layer are radially aligned with each other.

[0005] However, in practice, due to a mismatch between the size of the sleeve electrode and the thickness or actual cross-section of the nerve fiber bundle, the contact pressure between the sleeve electrode and the nerve fiber bundle may be too high or too low. Furthermore, if the sleeve electrode is incorrectly wrapped around the vagus nerve, a wrapping geometry may occur that strongly axially constricts or tightens the nerve fiber bundle on one side, while on the other side it is only loosely attached or even separated from the epineurium.

[0006] Although the process of wrapping or coiling the sleeve electrode around the nerve fiber bundle is largely autonomous, the operator performing the implantation procedure needs to maintain a high level of concentration to assess the wrapping result and make appropriate corrections as necessary. Such adjustments to the position and fit of the sleeve electrode after it has been applied to the nerve fiber bundle require extensive experience and careful handling to avoid damage to the nerve fiber bundle. Furthermore, the thin-film biocompatible carrier substrate of the sleeve electrode is typically transparent, i.e., made of light-transmitting materials, making it difficult, at the very least, to visually identify potential mismatches in the wrapping geometry of the sleeve electrode applied to the nerve fiber bundle.

[0007] Document DE 10 2007 036 862 A1 discloses an electrode device designed as a ligature for intraoperative nerve stimulation.

[0008] Document WO 2011 / 147876 A1 discloses an implantable collection electrode with directional marker connecting lines. Summary of the Invention

[0009] The objective of this invention is to provide a medical implant having a thin-film flexible substrate in which a material-inherent, shape-defined restoring force is imprinted, which, without external force, shapes the thin-film flexible substrate into a straight cylindrical wrapping sleeve. This allows, after the formation of a complete first wrapping layer, the complete first wrapping layer to be wrapped at least partially by at least one additional wrapping layer. The medical implant is further improved such that the operator performing the application of the wrapping sleeve around a nerve fiber bundle can more easily and safely visually capture and evaluate the wrapping result, i.e., determine whether the wrapping sleeve presents an ideal straight cylindrical sleeve shape or a wrapping geometry deviating from this shape. This determines whether the sleeve electrode should remain on the nerve fiber bundle or whether correction is necessary.

[0010] The solution to the task on which the invention is based is given in claim 1. Features that further refine the inventive concept in an advantageous manner are the subject of the dependent claims and the further description of the embodiments with reference to reference.

[0011] The medical implant according to the invention, having the features of the preamble of claim 1, is characterized in that at least one first-type local defining pattern is applied to a first winding layer region on a thin-film flexible surface substrate, and at least one second-type local defining pattern is applied to the at least one additional winding layer region. The at least one first-type and the second-type local defining patterns are applied to the thin-film flexible surface substrate such that they are perceptibly present from a radially external visual perspective.

[0012] Based on the radially identifiable first and second type patterns, the operator can directly identify whether the sleeve electrode has an excessively small or large cross-section or diameter relative to the nerve fiber bundle, and / or whether lateral displacement has occurred when the sleeve electrode autonomously wraps or coils around the nerve fiber bundle—that is, whether the sleeve electrode deviates from the ideal straight cylindrical shape and wraps around the nerve fiber bundle in a conical or frustum shape. In such cases, the operator can correct the fit of the sleeve electrode on the nerve fiber bundle or re-wrap it, or select and use a more suitable sleeve electrode if it is too small or too large.

[0013] A preferred embodiment of the medical implant of the present invention comprises a translucent, thin-film flexible surface substrate, which allows the at least one first-type locally defined pattern to be visually perceived radially from the outside through the at least one additional wrapping layer. Furthermore, to reliably capture the relative positions between the at least one first-type and one second-type locally defined pattern, it is advantageous that these at least two first-type and one-type patterns form a clear visual contrast and distinction with the translucent, thin-film flexible surface substrate and with each other. This can be achieved, in particular, through appropriately selected different colors.

[0014] To maximize the contrast between the two patterns (type 1 and type 2), in addition to or in combination with different color choices, distinguishability can also be enhanced through different shape and size choices. For example, it is conceivable to design the at least one type of partially defined pattern as a rectangle, while the at least one type of pattern as a circle.

[0015] Preferably, the at least one first-type and the second-type locally defined patterns are respectively applied to the radially outward-oriented surface of the thin-film flexible surface substrate formed as a wrapping sleeve, for example by printing and / or surface structuring processes. To ensure that the at least one first-type and the second-type locally defined patterns are visible even in the case of an opaque surface substrate, at least one radially covering section of the at least one additional wrapping layer containing the at least one first-type locally defined pattern is designed to be translucent or has a sufficiently large viewing opening through which the first-type locally defined pattern radially covered by the additional wrapping layer can be seen radially outward.

[0016] To predefine an ideal reference arrangement between the at least one first-type and the second-type patterns in space, during the formation of the wrapping sleeve, the at least one first-type local defining pattern and the at least one second-type local defining pattern are arranged along a common plane orthogonally intersecting the wrapping axis. This means that, when the sleeve electrodes are ideally applied to the nerve fiber bundle, at least two patterns of the first and second types are arranged continuously, either front-to-back or side-by-side, along the common circumferential edge line of the wrapping sleeve. The form and number of the first-type and second-type local defining patterns arranged on the thin-film flexible substrate are preferably chosen such that, when viewed radially from the outside, the local defining patterns are uniformly arranged in a continuous alternating sequence along the circumferential edge line.

[0017] Typically, the thin-film flexible substrate used to manufacture the sleeve electrode has a basic rectangular or square shape in its unfolded state (i.e., unwound state), with two opposing side edges. After the substrate is self-wound, these two side edges axially define both sides of the sleeve. Preferably, at least one locally defining pattern of type one and type two is arranged along a circumferential edge line adjacent to the two side edges of the substrate.

[0018] By using first and second type locally defined patterns arranged near the basal side edges of the two axially defined wrapping cuffs, respectively, the operator can easily see whether the cuff electrodes are correctly abutting the epineurium of the nerve fiber bundle. This check is particularly important when applying the cuff electrode device to perform spatially selective detection of neuronal signals along nerve trunks or nerve fiber bundles (especially along the vagus nerve) and spatially and temporally resolved application of neuronal stimulation signals. Attached Figure Description

[0019] The present invention will now be described by way of example and with reference to the accompanying drawings, without limiting the overall inventive concept. The drawings are as follows.

[0020] Figure 1 A straight cylindrical wrap sleeve is shown.

[0021] Figure 2 The thin-film flexible surface substrate of the wrapped sleeve in its unfolded state is shown.

[0022] Figures 3a, b, and c illustrate different winding states. Detailed Implementation

[0023] Figure 1 A self-winding sleeve 1 is shown, which is composed of a thin-film flexible substrate 2. During a heat treatment process, the inherent, shape-defined restoring forces of the material are imprinted into the substrate. Through these restoring forces, the thin-film flexible substrate 2 takes on the shape of a straight cylinder after self-winding and has a predetermined inner diameter dx. Because the sleeve 1 forms multiple loosely abutting winding layers 3 during self-winding, each sleeve 1 has a certain "margin" so that it can also functionally and correctly wrap larger nerve fiber bundles with a diameter slightly larger than the inner diameter dx predetermined by the heat treatment process.

[0024] To provide operators performing the application of the wrapping sleeve 1 around the nerve fiber bundle 9 with decision-making criteria to determine when the aforementioned "margin" is exhausted or exceeded, Figure 2 The markings M, which are arranged directly on the edge side of the thin-film flexible substrate 2 as shown in the figure, serve a purpose, which will be explained below.

[0025] Figure 2 A thin-film flexible surface substrate 2 in its unwound state (i.e., planar state) is shown. The rectangular surface substrate 2 is defined by two surface substrate side edges 4 extending parallel to each other and another side edge 5 orthogonally oriented to the two surface substrate side edges 4. The surface substrate lead-out sheet F for electrical leads extending laterally from the surface substrate 2 is mentioned for completeness only, but it is not relevant to the present invention.

[0026] When the thin-film flexible substrate 2 is autonomously wound, it will be wound around the side edge 5 into a straight cylinder, and its cylindrical axis corresponds to the winding axis oriented parallel to the side edge 5.

[0027] exist Figure 2In the illustrated case, the first surface segment I of the surface base 2 forms a first radially inner winding layer, which directly abuts against the epineurium of the nerve fiber bundle, while the adjacent second surface segment II of the surface base 2 forms a radially outer winding layer, which radially wraps around the inner winding layer. Near the two surface base side edges 4, a series of locally defined first-type patterns 6 and second-type patterns 7 are respectively arranged. The locally defined first-type patterns 6 are located near the edges in the first surface segment I corresponding to the inner winding layer. The locally defined second-type patterns 7 are located in the second surface segment II, which corresponds to the radially outer winding layer of the wrapping sleeve 1. Figure 2 In the cases shown, the first and second type of locally defined patterns 6 and 7 are designed as rectangular areas and distinguished from each other by colors that contrast with each other as much as possible. Alternatively, the selected colors may also be fluorescent and respond to a uniform excitation frequency with different emission frequencies, such as immunostains used in anatomical work.

[0028] The arrangement of the first and second type of partially defined patterns 6 and 7 is chosen such that they are each located on the circumferential edge line 10 that can be assigned to the wrap sleeve 1. An interval region 8 is provided between each two adjacent patterns 6 and 7, which is either composed of a preferably light-transmitting thin film-like flexible surface substrate, or (if the surface substrate 2 is opaque or insufficiently light-transmitting) designed as a through hole, such as an observation port, particularly in the second surface section II.

[0029] If the prefabricated wrapping sleeve 1 is wound around the nerve fiber bundle 9 in this manner, then during the ideal winding process (where the wrapping sleeve 1 has an inner diameter dx that is approximately equal to the outer diameter of the nerve fiber bundle 9), the following will be obtained: Figure 3a The winding result is shown in the figure.

[0030] In this configuration, the first and second type local defining patterns 6 and 7 are positioned along circumferential edge lines 10 extending close to the base-side edges 4 of the two surfaces, respectively. The first and second type local defining patterns 6 and 7, which are perceptible from a radially external visual perspective, are directly adjacent to each other in an alternating order and are identified as surface patterns of equal size.

[0031] The appearance of the wrapping sleeve, marked by the local defining patterns 6 and 7 of the first and second types, which is perceptible to the operator from a radial external perspective, indicates to the operator that the wrapping sleeve has been correctly applied around the nerve fiber bundle 9. If a different appearance is observed, this is a sign to the operator that the wrapping sleeve 1 needs to be corrected, and if necessary, it should be completely removed from the nerve fiber bundle 9 and reapplied.

[0032] Figure 3bThis illustrates a situation where the wrapping sleeve 1 is tilted, i.e., applied while forming a slightly conical shape along the nerve fiber bundle 9. In this case, the local defining patterns 6, 7 of the first and second types are not as... Figure 3a The arrangement shown is along a circumferential edge line 10, but is offset relative to this lateral (i.e. axial) direction.

[0033] Figure 3c This illustrates a case where the sleeve 1 is too small for the nerve fiber bundle 9, meaning the nerve fiber bundle 9 excessively expands radially around the sleeve 1, causing the first and second type of locally defined patterns 6 and 7 to not appear as marked areas with equal areas along the circumferential edge. For example... Figure 3b In the same situation, the wrapped sleeve 1 must also be loosened from the nerve fiber bundle 9 and reapplied.

[0034] also, Figure 3b and 3c The incorrect matches shown may also occur in combinations, which the operator can determine based on the ideal situation (see [reference]). Figure 3a Different pattern arrangements can easily identify these situations.

[0035] Especially when the wrapping sleeve 1 is designed as a cuff electrode, it has multiple individual electrodes 11 in the first surface segment I. These electrodes must be attached to the epineurium of the nerve fiber bundle 9 in a predefined position. Therefore, the cuff electrodes must be positioned in a precisely preset ideal location (e.g., Figure 3a (As shown) is applied to the nerve fiber bundle 9. According to the measures provided by the invention, namely, setting first and second type of local defining marks 6, 7, which are different from each other at least in shape, size or color, provides the operator with a decision criterion as to whether the wrapping sleeve is applied correctly or incorrectly around the nerve fiber bundle 9.

[0036] List of reference numerals in the attached diagram: 1. Wrap sleeve 2-sided base 3. Wrapping layer 4. Base side edge 5 Side edges 6 Type I Partially Defined Pattern 7. Type II Partially Defined Patterns 8. Light transmission interval 9. Nerve fiber bundles 10 circumferential edge lines 11 electrodes Section 1 II. Second Section dx inner diameter M mark.

Claims

1. A medical implant having a thin-film flexible surface substrate (2) in which a material-inherent, shape-defined restoring force is imprinted, said restoring force shaping the thin-film flexible surface substrate (2) into a straight cylindrical wrapping sleeve (1) without external force, such that after the formation of a complete first wrapping layer (3, I), the first wrapping layer is at least partially wrapped by at least one additional wrapping layer (3, II), characterized in that, At least one first type of local defining pattern (6) is applied to the region of the first winding layer (3, I) on the thin film flexible surface substrate (2) and at least one second type of local defining pattern (7) is applied to the region of the at least one additional winding layer (3, II), and the at least one first type of local defining pattern (6) and the at least one second type of local defining pattern (7) are applied to the thin film flexible surface substrate (2) such that they are perceptibly presented from the radial outside.

2. The medical implant according to claim 1, characterized in that, The thin-film flexible surface substrate (2) is translucent, and the at least one first-type and second-type locally defined patterns (6, 7) stand out visually in stark contrast to the translucent thin-film flexible surface substrate (2) and to each other.

3. The medical implant according to claim 1 or 2, characterized in that, The at least one first-type and second-type locally defined patterns (6, 7) are respectively applied to the radially outward-oriented surface of the thin-film flexible surface substrate (2) formed as a wrapping sleeve (1), and The surface area of ​​at least one of the first type of locally defined patterns (6) radially covering the region of the first winding layer (3, I) inside the at least one additional winding layer (II) is light-transmitting or has an observation port.

4. The medical implant according to any one of claims 1 to 3, characterized in that, The at least one first-type and second-type partially defined patterns (6, 7) can be distinguished from each other by one of the following visually perceptible appearance forms: color, shape, size.

5. The medical implant according to any one of claims 1 to 4, characterized in that, When forming the wrap sleeve (1), the at least one first type of partial defining pattern (6) and the at least one second type of partial defining pattern (7) are arranged along a common plane that intersects the wrapping axis orthogonally.

6. The medical implant according to any one of claims 1 to 5, characterized in that, The thin-film flexible substrate (2) has a basic rectangular or square shape, with two opposing substrate side edges (4) that axially define the wrap-around sleeve (1). The at least one first-type and second-type local defining patterns (6, 7) are arranged on the edge side adjacent to the two surface base side edges (4).

7. The medical implant according to claim 5 or 6, characterized in that, At least two first-type and second-type locally defined patterns (6, 7) are arranged on a thin-film flexible surface substrate (2) such that they are visible from the radial outside along the circumferential edge line (10) that can be assigned to the wrap sleeve (1) in an alternating order.

8. The medical implant according to any one of claims 1 to 7, characterized in that, The at least one first type and the second type of partial defining pattern (6, 7) are rectangular or square, and the first type and the second type (6, 7) are different from each other in color.

9. The medical implant according to any one of claims 1 to 8, characterized in that, The wrapping sleeve (1) is configured as a sleeve electrode device for extravascular or extraneural application around a blood vessel or nerve fiber bundle.

Images