Cuff-shaped medical implant
Patent Information
- Application Number
- JP2026519051
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-09-29
- Filing Date
- 2024-09-25
- Publication Date
- 2026-10-13
Smart Images
Figure 2026533890000001_ABST
Abstract
Description
[Technical Field]
[0001] The present invention relates to a cuff-shaped medical implant having a film-like, flexible planar substrate, wherein the planar substrate spontaneously and without external force takes on a straight cylindrical shape due to the inherent shape properties of the material, and the planar substrate has a cylindrical inner surface that, when implanted, can form extravascular or extraneuronal surface contact along internal cord-like structures in the body in the form of blood vessels or nerve fiber bundles. [Background technology]
[0002] European Patent No. 3204105 discloses a cuff electrode arrangement, also known as a cuff electrode, which comprises a flexible, biocompatible support substrate, preferably a polyimide film, on which a plurality of individual electrodes are provided on at least one side of the surface of the support substrate. Well-known cuff electrodes are used for spatially resolved measurement of nerve electrical signals and for selective electrical stimulation of individual nerve fibers running within a nerve fiber bundle. To ensure that the cuff electrode remains positioned along the nerve fiber bundle, preferably along the vagus nerve, in a tissue-friendly manner and as close to its original position as possible, the film-like support substrate is given material-specific mechanical prestress, thereby causing the film-like support substrate to form itself into a straight cylindrical wound cuff, forming at least one complete wound layer. The straight cylindrical cuff shape engraved into the film-like support substrate is selected according to the extraneuronal shape and size of the nerve fiber bundle so that the contact pressure applied by the cuff electrode to the epineurial membrane of the nerve fiber bundle is firmly maintained along the nerve fiber bundle, without constricting the nerve fiber bundle or placing excessive mechanical stress on it.
[0003] It cannot be ruled out that anatomically occurring biological structures, such as relative movement between the vagus nerve and the cuff electrode, may cause tissue irritation or inflammation, particularly at the axially opposed lateral edges of the cylindrically wound support material. To avoid irreversible damage or injury to the epineurial membrane of nerve fiber bundles, these should be eliminated or significantly reduced as much as possible.
[0004] Further examples of cuff-shaped implants are disclosed in German Patent No. 102017222362, which relates to a foil-like wound cuff having at least one flat winding that at least partially overlaps, forming a cylindrical cavity, and which can be specifically joined for the purpose of fixing along a blood vessel or nerve fiber bundle in the body by shape coupling and / or force coupling. The wound cuff functions purely as a fixation device and is used to withstand tensile forces acting on an implant placed in the body. In this case as well, it is important to avoid adverse effects or damage to organic structures by the wound cuff.
[0005] Further examples of cuff-shaped implants are described in European Patent No. 3833425, which is a protective structure for the cuff electrode described above, comprising two cylindrical hemishells joined together, and can transition from an open state in which the protective structure can be positioned around the cuff electrode applied along a nerve fiber bundle to a closed state in which the cuff-shaped protective structure completely surrounds the internal cuff electrode, preferably in the axial and circumferential directions. Similar to the cuff electrode, the protective structure is also flexible and made of a biocompatible film-like support material, within which a pre-stress is inherently incorporated to spontaneously form a closed cylindrical shape.
[0006] German Patent Application Publication No. 102007036862 describes an intraoperative nerve stimulation electrode having a strip-shaped planar base material that can be positioned around the vagus nerve by forming a single wrap similar to a cable tie. For fixation, the strip-shaped support base material is provided with transversely oriented wavy locking grooves that lock into the opening when a single wrap is made. [Overview of the project]
[0007] The object of the present invention is to further develop a cuff-shaped implant having a film-like flexible planar base material, wherein the planar base material spontaneously takes on a straight cylindrical shape without external force due to material-specific shaping, and has a cylindrical inner surface that can form surface contact with a string-like internal structure in at least a specific region when implanted, so as to avoid or at least significantly reduce tissue irritation to the internal structure caused by shear forces that may occur at the axially opposed end edges of the cuff-shaped implant.
[0008] The means for solving the fundamental problem of the present invention are shown in claim 1. Advantageous further developmental features of the present invention can be found in the dependent claims and in a further description with reference to specific illustrated embodiments.
[0009] A cuff-shaped implant according to the solution having the features of the preamble of claim 1 is characterized in that a film-like flexible planar substrate has, in the implanted state, two edge regions that face each other along a cylindrical axis related to a straight cylindrical shape, and each edge region is separated by an undulating edge contour line.
[0010] The fundamental idea of this invention is to prevent the linear axial edges of the cuff-shaped implant from directly contacting the tissue surface of each string-like internal structure, particularly the epineurium of nerve fiber bundles. The edge regions, monolithically connected to a film-like flexible planar substrate, are laterally bounded by edge contours that are mathematically continuously differentiable, i.e., have no angular discontinuities. The edge contours are preferably designed as sinusoidal or sinusoidal curves and are characterized by a repeating arrangement of wave-like projections that protrude laterally from each edge region. The wavy contour formation of the edge regions prevents localized tearing along the edge regions of the film-like flexible planar substrate by evenly distributing the shear force generated on the edge side during relative movement between the cuff-shaped implant and the string-like internal structure across all curved sections along the edge contour.
[0011] Furthermore, when the cuff-shaped implant exhibits a larger amplitude of motion relative to the string-like internal structure, the "wave peaks" formed as flaps projecting axially from each edge region of the wavy contour are folded back axially toward the planar substrate and abut against the radially outer surface of the cylindrical cuff shape. In this way, a rounded, funnel-shaped contour is formed at the edge between the epineurium or tissue surface and the folded wave-shaped region lobe, thereby preventing harmful tissue irritation during relative movement between the cuff-shaped implant and the string-like internal structure.
[0012] In a preferred embodiment, two edge regions defined by a wavy edge contour are thinner than the rest of the planar substrate to increase the flexibility of the edge region and allow the respective wave-shaped region lobes to fold more easily and quickly. Preferably, the film-like flexible planar substrate has a first film thickness D, typically 15 μm ≤ D ≤ 20 μm. The edge regions separated by the wavy edge contour are each at least one-quarter to half the thickness D. This increases the in-plane flexibility of the edge region and facilitates the folding action of the wave-shaped region lobes. The reduced film thickness within the edge regions also results in the restoring force imparted to the film-like flexible planar substrate for autonomous molding into a straight cylindrical shape having no restoring force at all, or only a negligibly small restoring force, in the regions near these edges. The size of the edge region is defined, on the one hand, by a length preferably corresponding to the circumference of a cuff-shaped implant, and on the other hand, by a width corresponding to at least twice the amplitude associated with the wavy edge contour.
[0013] The two axially opposing edge regions along the cylindrical shape contribute to the inherent rigidity of the cuff-shaped implant and also play a role in mechanical damping between it and the tissue surface of string-like internal structures such as the epineurium of nerve fiber bundles. As a result, a soft, rounded "impedance transition" is formed between the flexible, film-like planar substrate on the one hand and the organic tissue structure on the other.
[0014] In a preferred embodiment, the number and periodic or aperiodic order of individual waveforms along the edge contour are adapted to the length of the circumferential edge of the right cylindrical shape of the cuff-shaped implant such that the edge contours of both waveforms each completely enclose the circumferential edge of the right cylindrical shape only once, i.e., only once, so that the wave-shaped region lobes projecting axially from the planar substrate do not radially overlap with the second one. This ensures that folding related to the relative movement of the wave-shaped region lobes is not hindered, without collision with other wave-shaped region lobes connected to the flexible planar substrate in the form of a film.
[0015] The present invention provides a margin region laterally demarcated by a wavy margin contour line on the axially opposing periphery of a cuff-shaped implant that is independently formed as a straight cylinder, and is generally suitable for forming wound cuffs, particularly in combination with cuff electrodes, and especially in combination with cuff electrodes that have an electrode structure on the inner surface of the cylindrical side of their film-like flexible substrate, such as the cuff electrode described in European Patent No. 3204105, the publication mentioned at the beginning.
[0016] Similarly, it is reasonable to provide an edge region by the solution to a protective structure that can be assembled from two straight cylindrical semicircles to form a straight cylinder, as described in the aforementioned publication, European Patent No. 3833425. [Brief explanation of the drawing]
[0017] The present invention will be described below with reference to the drawings and based on embodiments, without limiting the general idea of the invention. [Figure 1] Figures 1a) to d) show a schematic tabular comparison between cuff-shaped implants that are known in themselves (left column of the table) and cuff-shaped implants formed as solutions (right column of the table). [Figure 2a] Figure 2a shows a protective structure assembled from two right cylindrical half-shapes. [Figure 2b] Figure 2b shows a protective structure assembled from two right cylindrical halves. DETAILED DESCRIPTION OF THE EMBODIMENTS
[0018] The left column of Figure 1a shows a known biocompatible flexible support substrate 1, for example in the form of a polyimide film, which has a rectangular basic shape, and as shown in the left column of Figure 1b, spontaneously assumes the shape of a right cylindrical rolled cuff 2 without the action of external force by means of shape imparting inherently engraved in the material. When the right cylindrical rolled cuff 2 is formed, the planar substrate 1 is wound around the planar substrate side edge 4 while forming at least one complete winding layer, and two side edges 7 that are orthogonally adjacent to the planar substrate side edge 4 and face each other constitute the peripheral side edges 7 that are axially opposed along the cylinder axis 3.
[0019] Instead of making the basic shape of the planar substrate 1 rectangular, a square basic shape or a similar shape is also conceivable.
[0020] In order to apply the implantable rolled cuff 2, which can be seen from the left column of Figure 1, along a cord-like internal structure 5, for example a nerve fiber bundle, in particular the vagus nerve, the planar substrate 1 is positioned laterally of the cord-like internal structure 5 in the unfolded state shown in Figure 1a, and is then applied in a self-fixing manner by spontaneously wrapping around the cord-like internal structure 5 (see the left column of Figure 1c).
[0021] When the rolled cuff 2 continuously moves 6 in the longitudinal direction along the cord-like internal structure 5, the peripheral side edges 7 of the rolled cuff 2 that are axially opposed to the cylinder axis 3 act as friction and cutting edges, and may damage the cord-like internal structure 5, for example in the form of local tissue delamination 8.
[0022] In order to avoid such damage, the biocompatible flexible planar base material of the cuff-shaped implant 2 according to the solution means * is a film-like flexible planar base material 1 *is modified to have two opposing edge regions 10, each of which is laterally delimited by a wavy edge contour line 11 (see the right column of Fig. 1a). The wavy edge contour line 11 has no corners and is continuously differentiable in the mathematical sense. As the edge contour line 11, a sinusoidal curve or a sine curve in which the wave peak-shaped lobes 12 protruding from the edge are periodically continuous is particularly suitable.
[0023] The length 9 of each edge region 10 delimited by the wavy edge contour line 11 substantially corresponds to the circumference of the cord-like internal body structure 5. Thereby, the wound cuff 2 * is applied around the cord-like internal body structure 5, it is ensured that the two axially opposing edge regions 10 along the cylindrical axis 3 of the wound cuff 2 only enclose the cord-like internal body structure 5 in a single layer (see the right column of Fig. 1b). The width 19 of the edge region 10 corresponds to at least twice, preferably 3 to 10 times the amplitude A of the wave peak-shaped lobe 12. * the cylindrical axis 3 * The width 19 of the edge region 10 corresponds to at least twice, preferably 3 to 10 times the amplitude A of the wave peak-shaped lobe 12.
[0024] In the implanted state, when a longitudinal relative movement 7 occurs between the wound cuff 2 * and the cord-like internal body structure 5, referring to the right column of Fig. 1c, the wave peak-shaped lobes 12 of the wavy structured edge region 10 fold radially outward, lean against the outside of the wound cuff 2 * lean against the outside of the wound cuff 2 * and a funnel-shaped contour 13 is formed between the wound cuff 2 and the surface of the cord-like internal body structure 5 (see the right column of Fig. 1d). The funnel-shaped contour 13 can completely avoid, or at least significantly reduce, the shear forces that would otherwise arise between the wound cuff 2 and the internal body structure 5 as a result of the aforementioned longitudinal relative movement 6, such that these shear forces do not cause irreversible damage to the tissue surface of the internal body structure 5. * and a funnel-shaped contour 13 is formed between the wound cuff 2 and the surface of the cord-like internal body structure 5 (see the right column of Fig. 1d). The funnel-shaped contour 13 can completely avoid, or at least significantly reduce, the shear forces that would otherwise arise between the wound cuff 2 and the internal body structure 5 as a result of the aforementioned longitudinal relative movement 6, such that these shear forces do not cause irreversible damage to the tissue surface of the internal body structure 5.
[0025] To facilitate or support the folding motion of the wave-shaped region lobes 12, the edge region 10 preferably has a lower thickness of the planar substrate 1 than the rest of the planar substrate 1. Typically, the planar substrate 1 is formed using a polyimide film with a thickness of 15 μm to 20 μm. In contrast, the thickness of the edge region 10 is about 1 / 2 to 1 / 4, which significantly improves or enhances the in-plane elasticity and the resulting deformability.
[0026] When an implantable wrap-around cuff is designed as a cuff electrode, the planar substrate 1 shown in the right-hand column of Figures 1a and 1b * The electrode structure 18 is located between two edge regions 10 and comprises a planar substrate region facing the plane of the drawing, and this electrode structure 18 is in direct contact with the tissue surface of the string-like internal structure 5, in particular with the epineurium of the vagus nerve.
[0027] Planar base material 1 * This is due to manufacturing reasons and the winding cuff 2 around the string-like internal structure 5. * To improve the stability of the fixed portion, it has a planar base material extension 16, thereby the winding manchette 2 * The degree of winding is improved, but the function of the edge region 10 is not impaired. For this reason, the planar base material extension 16 is the winding manchette 2 * It is narrower than the total length of 17.
[0028] Figure 2a shows a flexible, film-like planar substrate 1 in the form of two straight, straight cylindrical semi-circular shapes 15, monolithically connected along a linear connecting region 14. ** The image shows an alternative cuff-shaped implant formed according to the solution having, with edge regions 10 formed on the axially opposing circumferential edges, and each edge region being bounded by a wavy edge contour line 11. Figure 2b shows a shape state in which both straight cylindrical semicircles 15 slightly overlap to form a straight cylinder 16. As with the embodiment of the solution described above, referring to the figure in the right column of Figure 1, in this case as well, the edge regions 10 are bounded by the remaining planar substrate region 1 ** The planar substrate is formed with a thinner thickness compared to other substrates. [Explanation of Symbols]
[0029] 1,1 * ,1 ** :Planar base material 2,2 * : Planted winding manchets 3,3 * :Cylindrical shaft 4: Side edge of planar base material 5: String-like internal structures 6: Longitudinal motion 7: Peripheral edge 8: Irreversible damage, tissue detachment 9: Length 10: Border region 11: Edge contour 12: Wave-shaped region lobe 13: Funnel-shaped contour 14: Linear connecting region 15: Right cylindrical semi-circular 16: Planar base material extension part 17: Total length of the revolving cuff 18: Electrode structure 19: Border region width A: Amplitude of wave-shaped region lobes
Claims
1. A flexible, film-like surface substrate (1 ＊ ,1 ＊＊ A cuff-shaped medical implant having ) the planar base material (1 ＊ ,1 ＊＊ ) takes on a straight cylindrical shape spontaneously without external force due to the shape imprinted on the material itself, and the planar base material (1 ＊ ,1 ＊＊ ) forms the inner surface of the cylindrical side, and the inner surface of the cylindrical side can, in the implanted state, form extravascular or extraneuronal surface contact along internal cord-like structures (5) in the form of blood vessels or nerve fiber bundles within the body. The film-shaped flexible planar base material (1 ＊ , 1 ＊＊ ) has two edge regions (10) facing each other along the cylindrical axis (3 ＊ ) corresponding to a right cylindrical shape in an implanted state, wherein each of the edge regions (10) is bounded by a wavy edge contour line (11), the cuff-shaped medical implant.
2. The aforementioned film-like flexible planar substrate (1 ＊ ,1 ＊＊ A cuff-shaped medical implant according to claim 1, characterized in that a rectangular or square basic shape is assigned to the )
3. The cuff-shaped medical implant according to claim 2, characterized in that the two edge regions (10) are arranged along two opposing sides of the basic rectangular or square shape.
4. The two edge regions (10) are each a wound cuff (2 ＊ A cuff-shaped medical implant according to any one of claims 1 to 3, characterized in that it extends completely once in the circumferential direction around the right cylindrical shape of ).
5. A cuff-shaped medical implant according to any one of claims 1 to 4, characterized in that the edge contour line (11) defining the edge region (10) is continuously differentiable.
6. The cuff-shaped medical implant according to claim 5, characterized in that the edge contour line (11) corresponds to a sinusoidal curve or sinusoidal curve.
7. The aforementioned film-like flexible planar substrate (1 ＊ ,1 ＊＊ A cuff-shaped medical implant according to any one of claims 1 to 6, characterized in that it has a first film thickness D except for the edge region (10), and has a second film thickness smaller than the first film thickness D in the edge region (10).
8. The second film thickness is smaller than the first thickness D by a coefficient F, and the coefficient F satisfies the condition 1 / 2 ≥ F ≥ 1 / 4. The first film thickness D is characterized in that 15 μm ≤ D ≤ 20 μm, as described in claim 7, for a cuff-shaped medical implant.
9. The aforementioned film-like flexible planar substrate (1 ＊ ) is a coiled cuff (2 ＊ ) formed in the manner of the winding manchette (2 ＊ In the above, the film-like flexible planar substrate (1 ＊ ) is the aforementioned film-like flexible planar substrate (1 ＊ A cuff-shaped medical implant according to any one of claims 1 to 8, characterized in that it can be formed by spontaneously rolling up around a lateral edge (4) which can be assigned to a )
10. The aforementioned wound manchette (2 ＊ ) is formed in a manner suitable for attaching along and around a string-like internal structure (5), A medical implant in the shape of a cuff according to claim 9, characterized in that an electrode structure (18) is attached to at least the inner surface of the cylindrical side of the wound cuff.
11. The aforementioned film-like flexible planar substrate (1 ＊＊ ) are monolithically connected along a linear connecting region (14), and the cylindrical shaft (3 ＊ A cuff-shaped medical implant according to any one of claims 1 to 8, characterized in that it has two straight cylindrical semi-shapes (15) whose boundaries are defined by film-like substrate edges oriented parallel to the ), and these semi-shapes can be brought into contact with each other by butting them together or overlapping them together to form a straight cylindrical shape.