Cable with cable sections having different degrees of stiffness, and method for producing such a cable

Abstract

The cable (10) has cable sections (10A, 10B, 10C) with different degrees of stiffness. The cable (10) has a cable element (22) which has a curable material, wherein, in order to form the cable sections (10A, 10B, 10C) with different degrees of stiffness, the cable element (22) has longitudinal sections (24A, 24B, 24C) with different degrees of curing. The material is in particular a sinterable PTFE. The cable (10) can be designed for partial implantation in a human body.

Description

[0001] Page 1

[0002] Cables with cable sections exhibiting different stiffnesses, and methods for manufacturing such a cable.

[0003] The invention relates to a cable for the transmission of energy, data and / or fluids with cable sections having different stiffnesses, and to a method for manufacturing such a cable.

[0004] The cable is specifically designed and / or suitable for the electrical, data, and / or fluid connection of devices and / or machines. Optionally, the cable can be designed and / or suitable for partial implantation in the human body. In particular, the cable can be used to supply power to a so-called heart pump, also known as an artificial heart or a ventricular assist device (VAD). Such a heart pump is an implantable mechanical pumping system that supports a patient's diseased heart. The pump receives power and control signals via the cable, which runs to a power supply unit worn outside the body. The cable typically exits the body in the abdominal cavity. To prevent injury, the cable must be highly flexible at the exit point.In contrast, at the opposite, proximal end, i.e., the end facing the heart pump, high stiffness is desired, particularly to allow the cable to be inserted into a vein and guided from there towards the heart. Once implanted, the cable runs from the heart pump initially within the vein, exits it, and is routed through the body, especially under the skin, until it reaches the exit point in the abdominal cavity, where it exits the body.

[0005] Such a heart pump with attached cable can be found, for example, in EP 3 090 767 A1.

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[0007] German patent DE 601 22 152 T2 discloses an electrically conductive catheter shaft with a resistance heater, which has areas of varying stiffness. To create these areas of varying stiffness, the sheath of the catheter shaft has a varying thickness. This is achieved by applying coaxial layers of different lengths. The layers are applied, for example, by heat shrinking.

[0008] From DE 693 18 183 T2 an implantable electrical conductor with a biocompatible outer sheath with two layers can be taken, wherein the inner layer is formed from an impermeable plastic tube, onto which a porous PTFE tube is wound as the outer layer for improved flexibility.

[0009] EP 2 376 179 B1 describes a flexible implantable lead with electrodes formed in different length ranges.

[0010] The invention is based on the objective of providing a cable for energy, data, and / or fluid transmission in devices and / or machines, which has cable sections with different stiffnesses, and of providing a method for manufacturing the cable. Based on the aforementioned prior art, it can also be an objective of the invention to provide a cable suitable for use in implanted or implantable devices, which has cable sections with different stiffnesses, and of providing a method for manufacturing it.

[0011] The problem is solved according to the invention by a cable for transmitting energy, data, and / or fluids. The cable can optionally be designed for partial implantation in a human body, particularly for, e.g., the electrical supply of implanted or implantable devices, such as a heart pump. The cable can also be designed as a conductor or referred to as a conductor.

[0012] The cable has axial, i.e., longitudinally running, cable sections with different stiffnesses. To form the different stiffnesses...

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[0014] Regarding cable stiffness in the various cable sections, the cable has a cable element that at least contains or consists of a stiffenable and / or curable material, whereby the cable element has longitudinal sections with different degrees of curing to create the cable sections with the different stiffnesses. Curing or hardening refers in particular to stiffening. Specifically, the degree of curing refers to the degree of stiffening.

[0015] The object is further solved according to the invention by a method for producing such a cable in which a cable element is integrated with a stiffenable and / or curable material and the stiffenable and / or curable material is cured differently in different longitudinal sections, so that longitudinal sections of the cable element with different hardness and thus cable sections with different stiffness are produced.

[0016] In this context, a stiffenable and / or curable material is generally understood to be a material, in particular a plastic, which in its initial (unstiffened and / or cured) state is softer and more flexible than in its stiffened and / or cured state. Conversely, in its stiffened and / or cured state, the material is harder and exhibits higher stiffness compared to its initial state.

[0017] The degree of curing generally refers to the extent to which stiffening and / or hardening has progressed. A degree of curing of 0% means that the material is still in its initial state, while a degree of curing of 100% means that the material is completely stiffened and / or hardened. If the material is, for example, a crosslinkable system, the degree of curing corresponds to the degree of crosslinking, i.e., the proportion to which the crosslinkable components of the material are crosslinked. The degree of curing is directly correlated with the degree of hardness and thus also with the stiffness of the material. Therefore, stiffness increases with increasing degree of curing.

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[0019] The particular advantage here lies in the fact that the differently stiff longitudinal sections of the cable element, and thus the differently stiff cable sections, can be manufactured with precision and relative ease. In particular, standard manufacturing processes used in cable harness production can be utilized. Curing methods, such as heat treatment or irradiation (e.g., with IR light), are applied section by section to cure the longitudinal sections of the cable element. The cable element is therefore treated differently in its various longitudinal sections to effectively control the curing process. Key process parameters include the duration and intensity (e.g., temperature or radiation intensity) of the curing treatment.

[0020] Therefore, complex additional measures, such as the section-by-section insertion of supplementary stiffening elements or the application of section-by-section wrappings or overmolding, are not necessary. In particular, such measures are avoided. Traditionally, so-called guide rods are sometimes integrated into the cable. However, the use of such guide rods is preferably omitted. To create sections with different stiffnesses, different materials are sometimes used in different section areas, e.g., for the outer sheath. However, the use of different materials to create sections with different stiffnesses is also preferably avoided.

[0021] Overall, this measure allows for the reliable production of such a cable with cable sections of varying stiffness using a simple manufacturing process. In particular, this measure enables the production of a medical cable, specifically for use with implanted and / or implantable devices, such as a heart pump, using this simple manufacturing process. This cable exhibits particularly high stiffness in its proximal section (facing the heart pump) and low stiffness, and thus high durability, in its distal section (away from the heart pump).

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[0023] It has flexibility to minimize the risk of injury, especially in the area where it exits the abdominal wall.

[0024] In a preferred embodiment, the material is a sinterable material, in particular a sinterable plastic, wherein the different degrees of hardening are formed by different sintering grades.

[0025] In this context, "hardening" therefore also refers specifically to sintering.

[0026] The use of a sinterable material offers the distinct advantages that different degrees of sintering, and thus also degrees of hardening and consequently different section-by-section hardness and stiffness, can be precisely and permanently achieved through a suitable sintering process. It is particularly noteworthy that the sintering degree, once established, is maintained over the long term. Furthermore, sinterable plastics often exhibit properties in their unsintered or partially sintered state that are well-suited for use in cables. For example, such a sinterable plastic is non-sticky even in its initial state.

[0027] PTFE (polytetrafluoroethylene, also known as polytetrafluoroethene or -ethylene) is a particularly suitable material for sintering. Sinterable PTFE is generally well-known and widely used in cable manufacturing. Sintering PTFE specifically involves a targeted heat treatment of the unsintered material. By selecting the process parameters, particularly temperature and duration of the heat treatment, the degree of sintering, and thus the desired hardness and stiffness of the respective longitudinal section of the cable element, can be easily controlled.

[0028] In a preferred embodiment, an unsintered component, e.g., a strip made of PTFE, is used to form the cable element. Such a component is commercially available and can be used reliably in the process.

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[0030] The tape typically has a thickness of 30–100 pm, preferably 40–80 pm, and particularly 50–76 pm. Preferably, only one layer or only a few layers (a maximum of five layers, preferably one to three layers, and particularly exactly two layers) are applied. The total thickness of the layers used is therefore, for example, in the range between 30 pm and 500 pm, preferably less than 150 pm.

[0031] For ease of processing, the tape covers at least part, and preferably completely, the cable component. Preferably, the tape is wrapped around at least one cable component. A cable component is, for example, a strand, a conductor, a wire, a tape, a filler, a strain relief element, a hose, a shield, and / or a jacket. The cable component is, in particular, a part of the cable core.

[0032] To produce the cable element with the longitudinal sections with different sintering degrees, the preferred method is to first apply a strip of unsintered PTFE at least partially to a cable component, in particular by winding it on, and then to carry out the sintering treatment, especially temperature treatment, to form the longitudinal sections with different sintering degrees.

[0033] In a preferred embodiment, the cable element is designed as a preferably internal wrapping of at least one cable component. Alternatively or optionally, the cable element is the cable component onto which the tape is at least partially applied, in particular around which the tape is wrapped.

[0034] In principle, it is also possible that the cable element is an intermediate sheath, which is, for example, concentrically surrounded by one or more sheath layers.

[0035] Due to its good properties, PTFE is particularly suitable for use inside the human body.

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[0037] Alternatively or optionally, the cable element can be designed as a strand running inside the cable. The cable element is therefore located within the cable along with other electrical conductor elements and forms a sub-element of the cable core, which is surrounded by a cable sheath, possibly consisting of multiple layers. For example, a non-electrical conductor strand is wrapped with PTFE tape and sintered differently in sections as appropriate. Alternatively, an electrical conductor strand, such as a supply wire, can also be wrapped with PTFE tape and sintered as appropriate.

[0038] According to a preferred embodiment, the cable element is designed as a hollow strand, e.g., a tube, which thus has an inner cavity. A guide wire or other filament is inserted through this cavity, at least temporarily, to facilitate implantation and routing of the cable within the human body. After implantation, such a filament is removed, ensuring the desired low stiffness and thus high flexibility, particularly at the point where the cable exits the abdominal wall. The hollow strand is therefore specifically designed for the reversible insertion of such a filament.

[0039] In a preferred embodiment, the cable has a diameter that is constant along its length. Here, "length of the cable" refers to its entire length, excluding the connection components at the two opposite ends. To achieve the different stiffnesses in the various longitudinal sections, variations in the cable thickness, such as those resulting from additional banding or stiffening elements, are avoided. This is a significant advantage of the cable and manufacturing process described here: the different stiffnesses in the various cable sections are achieved with the same material thickness of the stiffening and / or curing material.

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[0041] In a preferred embodiment, the material thickness of the stiffenable and / or curable material is generally constant over the entire length of the cable. The different stiffnesses are preferably achieved exclusively through varying degrees of curing.

[0042] If the cable is implantable and / or implanted, it generally extends from a distal end to a proximal end, with the proximal end facing the heart in the implanted state and the distal end facing away from the heart and running outside the body. The distal end has a lower stiffness than the proximal end. Therefore, a proximal cable segment with high stiffness, particularly the highest stiffness, is formed in the region of the proximal end. This proximal cable segment can vary considerably in length, e.g., between 5 cm and 50 cm. Preferably, the cable segment has a length in the range of 10 to 40 cm, particularly in the range of 20 to 30 cm.

[0043] At its distal end, the cable has a distal section that exhibits low stiffness, and in particular, the lowest stiffness. This distal section also extends, for example, over a length of at least 20 to 50 cm. In any case, the length of the distal cable section is sufficiently dimensioned so that the point of exit from the abdominal cavity exhibits the lowest stiffness and the highest flexibility.

[0044] The proximal and distal cable sections preferably exhibit a constant stiffness along their entire length. The degree of hardening, in particular the degree of sintering of the cable element, is therefore constant along the length of the respective cable section.

[0045] In principle, it is possible that the distal cable section with the lowest stiffness connects directly to the proximal cable section with the highest stiffness.

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[0047] In a preferred embodiment, however, a transition section is arranged between the distal and proximal cable sections, in which the stiffness is reduced from the high stiffness of the proximal cable section to the low stiffness of the distal cable section. This preferably occurs continuously, so that the stiffness in the transition section decreases progressively towards the distal cable section. This is achieved by a progressively lower degree of hardening towards the distal cable section.

[0048] In terms of process engineering, this is achieved by continuously adjusting and, in particular, increasing process parameters for curing, such as the temperature level and / or duration of the (temperature) treatment, from the distal cable section towards the proximal cable section in order to achieve the increasing degree of curing.

[0049] Alternatively, the invention also provides that the transition section has exactly a degree of stiffness and / or exactly a fixed value of stiffness that lies between the high stiffness of the proximal cable section and the low stiffness of the distal cable section.

[0050] As already mentioned, the cable is specifically designed for implantation, e.g., for use with implanted and / or implantable devices such as a heart pump. Accordingly, the proximal end, and thus the proximal cable section, is designed for connection to a device implantable in the human body, particularly a heart pump, and is specifically connected to the implantable device.

[0051] Correspondingly, the distal end, and thus the distal cable section, is preferably designed for connection to a power supply unit and, in particular, is also connected to it. The power supply unit is, in particular, a control unit for controlling the device, especially the heart pump, and / or a unit for supplying power to the device, especially the heart pump.

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[0053] At least one of the two ends, and preferably both ends, are designed for a reversible, detachable connection. Alternatively, at least the proximal end is permanently and irrevocably connected to the device, in particular the heart pump.

[0054] Exemplary embodiments of the invention are explained in more detail below in connection with the figures. These are shown in simplified representations:

[0055] FIG 1 a partially implantable system with a heart pump which is connected to a power supply unit via a cable,

[0056] FIG 2 shows the cable in a simplified side view,

[0057] FIG 3 shows a sectional view through the cable according to a first embodiment as well as

[0058] FIG 4 shows a sectional view through the cable according to a second embodiment.

[0059] An implantable system 2 shown in FIG 1 has a heart pump 4 with two tubes 6 attached to it, through which, in the implanted state, blood is pumped from a heart chamber into an aorta.

[0060] The heart pump 4 is controlled and powered by a power supply unit 8, which, when the heart pump 4 is implanted, is located outside the human body. This power supply unit 8 integrates, in particular, a control unit and / or a power supply unit, for example, a battery. Alternatively, the power supply unit can also be housed in a separate device.

[0061] The supply unit 8 is connected to the heart pump 4 via an electrical cable 10. When implanted, this cable therefore runs partially inside the human body and exits the body at an exit point A, typically in the abdominal wall. This exit point A is shown by a dashed line in FIG. 1.

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[0063] Cable 10 is subdivided into cable sections with different stiffness. Specifically, cable 10 has a proximal cable section 10A, which, when connected, is attached to the heart pump 4. This is followed by a middle transition section 10B, which in turn is connected to a distal cable section 10C. This distal section has a distal end that, when assembled, connects cable 10 to the supply units 8.

[0064] The proximal cable section 10A exhibits high, and in particular the highest, stiffness. It typically extends over a length of 10 to 20 cm.

[0065] The proximal cable segment 10A has sufficiently high stiffness to be shear-resistant. This means that the stiffness is high enough to allow the proximal cable segment 10A to be pushed through a vein or artery towards the heart.

[0066] In contrast, the distal cable section 10C exhibits lower stiffness compared to the proximal cable section 10A, and in particular, the lowest overall stiffness. Specifically, the distal cable section 10C exhibits this low stiffness in the exit region A. In particular, the cable 10 shows high bending flexibility in the region of the distal cable section 10C. The distal cable section 10C is, in particular, not shear-stiff – unlike the proximal cable section 10A.

[0067] The transition section 10B exhibits a stiffness value that lies between the stiffness of the proximal cable section 10A and the distal cable section 10C. It is also possible that in the transition section 10B, the stiffness of the cable 10 is reduced from the high stiffness of the proximal cable section 10A to the low stiffness of the distal cable section 10C, particularly continuously.

[0068] Figure 2 shows a simplified side view of cable 10 (without

[0069] Outer sheath 18 and without the connection areas for connection to the

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[0071] Heart pump 4 and the supply unit 8). Internal cable components, such as supply wires 12 or control lines 14, are shown with dashed lines. These together form a cable core 16, which is surrounded by one or more intermediate windings 28. The wound cable core 16 is generally surrounded by an outer sheath 18 (not shown).

[0072] In the embodiment shown in FIG. 2, the intermediate winding 28 is formed by a PTFE tape 20. During manufacturing, the PTFE tape 20 is first wound around the cable core 16. The initially unsintered PTFE material is then sintered, with different process parameters being set in the different cable sections 10A to 10C, resulting in different sintering degrees and thus different hardnesses in these sections. The cable core 16 is therefore a cable component around which the PTFE tape 20 is wound.

[0073] These varying stiffnesses are achieved solely through the different sintering grades, eliminating the need for additional stiffening elements or area-specific sheathing. Accordingly, cable 10 also maintains a constant outer diameter d along its entire length.

[0074] Overall, the PTFE band 20 forms a cable element 22 which, corresponding to the cable sections 10A to 10C, has longitudinal sections with different degrees of sintering, namely a proximal longitudinal section 24A, a transitional longitudinal section 24B and a distal longitudinal section 24C, whereby the cable sections 10A-10C with the different stiffnesses are reached via these longitudinal sections 24A-24C.

[0075] FIG. 3 shows a cross-sectional view through a cable, in particular according to FIG. 2, where the outer sheath 18 is also shown. It can be seen that the cable components 12, 14, which form the cable core 16, are surrounded by the cable element 22 made of PTFE, which is formed as the intermediate winding 28 from the PTFE strip 20. The intermediate winding 28 has in

[0076] Last saved 1:30 PM, 1909 2024 Page 13 The different longitudinal sections exhibit different sintering grades. The intermediate winding, or the cable core 16 wrapped with the intermediate winding 28, is surrounded by the outer sheath 18, which has constant properties over its entire length, in particular a constant stiffness.

[0077] Figure 4 shows an alternative embodiment in which the cable element 22 is a further cable component, namely a (plastic) strand 26, wrapped with the PTFE tape 20. The cable element 22, together with the supply conductors 12 and control lines 14, forms the cable core 16, which is surrounded by the outer sheath 18. In particular, the strand 26 is wrapped with the PTFE tape 20, which has different degrees of sintering in different longitudinal sections. In this case, the cable element 22 therefore consists of the PTFE wrapping and the inner strand 26. The outer sheath 18 preferably has constant properties over its entire length, in particular a constant stiffness.

[0078] To form the cable element 22 according to FIG. 4, it is preferably carried out by first wrapping an unsintered strip around the strand 26 and then carrying out the sintering with the section-wise different process parameters.

[0079] In alternative variants, not shown in detail here, the cable element 22 is formed, for example, by an electrical conductor (e.g. supply conductor 12) having a PTFE sheath with the differently hardened longitudinal sections 24A-24C, or by integrating a length component, e.g., another strand made of pure PTFE, for example as a braid, as a braid, etc., with the differently hardened longitudinal sections 24A-24C into the cable structure.

[0080] Alternatively, the cable element 22 can also be designed as a hollow strand, e.g., a hose, which in particular consists entirely of PTFE. In this case, for example, the strand 26 used in the manufacturing process is pulled out again. Such a design variant is suitable

[0081] Last saved 1:30 PM, 1909 2024 Page 14 For example, a shear-resistant filament, such as a shear wire, can be inserted into the inner cavity of the hollow strand to simplify the insertion and routing of cable 10. This filament is removed after implantation.

[0082] The method described here enables the simple and reliable production of a cable 10 with cable sections 10A-10C of varying stiffness. The different stiffnesses of the various cable sections 10A-10C are achieved exclusively through the different stiffening and / or curing of the longitudinal sections 24A-24C of the cable element 22.

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[0084] Reference symbol list

[0085] 2 implantable systems

[0086] 4 Heart pump

[0087] 6 hoses

[0088] 8 supply units

[0089] 10 cables

[0090] 10A proximal cable section

[0091] 10B Transition section

[0092] 10C distal cable section

[0093] 12 supply line

[0094] 14 Control line

[0095] 16 cable core

[0096] 18 Outer jacket

[0097] 20 PTFE tape

[0098] 22 cable element

[0099] 24A-C Longitudinal sections

[0100] 26 strand

[0101] 28 Intermediate winding d diameter

[0102] Last saved at 1:30 PM, 1909 2024

Claims

Page 16 Claims 1. Cable (10) for transmitting energy, data and / or fluids, wherein the cable (10) has cable sections (10A, 10B, 10C) with different stiffnesses, characterized in that a cable element (22) is integrated into the cable (10) which has a stiffenable and / or curable material, wherein, for the formation of the cable sections (10A, 10B, 10C) with different stiffnesses, the cable element (22) has longitudinal sections (24A, 24B, 24C) with different degrees of curing.

2. Cable (10) according to claim 1, characterized in that the cable (10) is suitable and / or designed for at least partial implantation in a human body, in particular for supplying electrical implanted or implantable devices.

3. Cable (10) according to claim 1 or 2, characterized in that the material is a sinterable material and that the different degrees of hardening are formed by different sintering grades.

4. Cable (10) according to one of the preceding claims, characterized in that the material is PTFE.

5. Cable (10) according to one of the preceding claims, characterized in that a component which is unsintered in the initial state, preferably a strip (20) made of PTFE, is used to form the cable element (22).

6. Cable (10) according to one of the two preceding claims, characterized in that a cable component (16, 26) is at least partially covered by the PTFE, preferably surrounded by the PTFE.

7. Cable (10) according to one of the preceding claims, characterized in that the cable element (22) is designed as a wrapping of the at least one cable component (16, 26) and / or as an intermediate sheath (18). Last saved at 1:30 PM, 1909 2024 Page 17 8. Cable (10) according to one of the preceding claims, characterized in that the cable element (22) is designed as a strand running inside the cable (10), in particular as a hollow strand.

9. Cable (10) according to one of the preceding claims, characterized in that the cable (10) has a diameter (d) that is constant over its length.

10. Cable (10) according to one of the preceding claims, characterized in that the cable (10) extends from a distal cable section (10C) to a proximal cable section (10A), wherein the distal cable section (10C) has a lower stiffness than the proximal cable section (10A).

11. Cable (10) according to the preceding claim, characterized in that a transition section (10B) is formed between the distal cable section (10C) and the proximal cable section (10A), in which the stiffness is reduced from a high stiffness of the proximal cable section (10A) to the low stiffness of the distal cable section (10C).

12. Cable (10) according to one of the preceding claims, characterized in that the proximal cable section (10A) is designed for connection to an implantable device, in particular a heart pump (4).

13. Method for manufacturing a cable (10) suitable and / or designed for the transmission of energy, data and / or fluids, in particular according to one of the preceding claims, wherein the cable (10) has cable sections (10A, 10B, 10C) with different stiffnesses, characterized in that a cable element (22) is integrated with a stiffenable and / or curable material and the stiffenable and / or curable material is stiffened and / or cured differently in different longitudinal sections (24A, 24B, 24C), such that longitudinal sections (24A, 24B, 24C) of the cable element (22) have different hardnesses and Last saved at 1:30 PM, 1909 2024 Page 18 so that cable sections (10A, 10B, 1OC) with different stiffnesses can be created.

14. Method according to the preceding claim, wherein a sinterable material and in particular a PTFE is used as the curable material.

15. Method according to the preceding claim, wherein an unsintered PTFE strip (20) is applied at least partially to at least one cable component (12, 16), in particular wound around it, and then treated differently in the various longitudinal sections (24A, 24B, 24C) to produce the different degrees of hardness. Last saved at 1:30 PM, 1909 2024

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