EP4329858A2

EP4329858A2 - Magnetic resonance tomography-safe (mr-safe) control cable

Info

Publication number: EP4329858A2
Application number: EP22727046.9A
Authority: EP
Inventors: Klaus Düring; Nasib Dlaikan-Campos; Arelí Graciela Luttmann
Original assignee: Marvis Interventional GmbH
Current assignee: Marvis Interventional GmbH
Priority date: 2021-04-29
Filing date: 2022-04-29
Publication date: 2024-03-06
Also published as: US20240091496A1; WO2022229443A2; WO2022229443A3; DE102021111091A1

Abstract

According to the invention, a magnetic resonance tomography-safe (MR-safe) control cable for controlling a medical device is provided. The control cable can be arranged in a medical device, wherein the control cable is formed from a non-ferromagnetic matrix material in which a reinforcing material is embedded, and wherein the control cable is structurally configured in such a way that, by displacing the control cable in and counter to an axial direction of a medical device, the medical device can be controlled, or in such a way that a functional element, which can be coupled to the control cable, of a medical device can be controlled.

Description

Magnetic resonance imaging safe (MR safe) control cable

The present invention relates to a magnetic resonance imaging safe (MR safe) control cable.

Control cables are used in medical devices, for example to control the device and/or to pull and/or push parts of the device. In the case of conventional medical devices of this type, these control cables are made of metal. These medical devices can be used in X-ray-guided medical procedures, but not in magnetic resonance imaging (MRI)-guided medical procedures because metals in MRI are electrically conductive and can heat up, which can endanger the patient and doctor.

Examples of such medical devices are steerable catheters, steerable sheaths, stent ejection systems, occluder ejection systems, coil ejection systems, atrial flow regulator ejection systems, bioptomes, TAVR, TMVR & LAA delivery systems, steerable ablation catheters, thrombectomy systems, steerable needles, steerable guide wires, etc.

WO 2015/161927 describes a medical instrument that can be inserted into a human or animal body, the medical instrument having an instrument body, and the instrument body having at least one poorly electrically conductive rod-shaped body made of a matrix material and not metallic filaments is formed.

A guide wire emerges from US Pat. No. 10,035,002 B2. This has a sensor with a cable and is not MR safe.

Conventional pultrusion devices are described in DE 696 05 645 T2 and US 2020/0 307 127 A1. US 2010/0198049 A1 discloses a catheter with a controllable tip that was already invented for use in MRT, but can only be used in MRT under certain conditions because it is not MR-safe but only MR-conditional is. The control cables are designed as conductive metal wires to make the catheter tip visible through an active MR marker. This entails the risk of endangering the patient and doctor if the permitted, limited application conditions of such a product are not fully complied with in the interventional MRI.

The object of the present invention is to provide an alternative to control cables for medical devices known from the prior art.

Another object is to provide control cables that have improved mechanical properties.

In addition, it is an object of the present invention to provide control cables, in particular for medical devices, and such a medical device, which can be manufactured in a simple manner and/or with high quality.

Another object is to provide a method for manufacturing such control cables.

In order to solve these objects, the invention has the features specified in the independent patent claims. Advantageous configurations thereof are specified in the respective subclaims.

According to the invention, a magnetic resonance tomography-safe (MR-safe) control cable is provided for controlling a medical device. The control cable can be arranged in a medical device, the control cable being made of a non-ferromagnetic matrix material in which a reinforcing material is embedded, and the control cable being structurally designed in such a way that a displacement of the control cable in and against an axial direction of a medical device, the medical device can be controlled, or that a functional element of a medical device that can be coupled to the control cable can be controlled.

A functional element of a medical device can be controlled, for example, by a displacement, preferably in and against an axial direction of the medical device. direction, and/or a rotation and/or an opening and/or a closing of the functional element (eg a forceps of a bioptome) are to be understood.

In steerable tubular medical devices, such as catheters, metal wires are often used as pull or control cables. However, due to the electrical conductivity of metal wires and the associated heating, such metal wires cannot be used in magnetic resonance tomography (MRI) methods.

Because the control cable according to the invention is made of a non-ferromagnetic matrix material in which a reinforcement material (one or more non-metallic reinforcement fibers) is embedded, an MR-safe control cable is provided. Such a control cable represents an alternative to known control cables which are formed from a single material.

In the context of the present invention, the term “magnetic resonance imaging safe” means an MR safe article as defined in ASTM standard F2503-13.

According to ASTM Standard F2503-13, this means: "MR Safe - an article that presents no known hazards when exposed to an MR environment. MR Safe articles are made of materials that are electrically non-conductive, non -are metallic and not magnetic.

Non-metallic means that the control cable must not contain any metal parts with a length greater than 1 cm. However, the control cable can contain small, dispersed amounts of metal microparticles as MR marker particles. The amount of metal microparticles can be a maximum of 10% by weight (w/w) or 10% by weight or 5% by weight or 4% by weight or 3% by weight or 2 % by weight, 1% by weight and 0.5% by weight, respectively. In the context of the present invention and also according to the ASTM standard, such marker concentrations are referred to as non-metallic cal materials.

Accordingly, a control cable according to the invention is non-electrically conductive and non-magnetic and non-metallic. This means that the control cable consists of non-electrically conductive and non-metallic and non-magnetic materials. A fiber composite material can be provided as the starting material for an MR-safe control cable according to the invention. This includes the reinforcement material, which can be formed in particular from fibers that are embedded in the matrix material.

Both duroplastic and thermoplastic polymers can be provided as matrix material. The relatively inexpensive polyester resins, vinyl ester resins and epoxy resins, for example, are used as duroplastic matrix materials. In order to improve special properties such as sliding properties, subsequent deformability under heat or abrasion resistance, thermoplastic fiber composites can also be produced.

For example, polyamides, polypropylenes and polyethylenes are used as matrix materials.

The matrix material can thus be a plastic such as epoxy resin, polyester resin, vinyl ester resin, polyamide, PEEK, PEBAX, polyethylene, polypropylene, polyurethane, silicone, polylactic acid polymers.

In the context of the present invention, a reinforcing material is understood as meaning one or more reinforcing fibers. Reinforcing fibers include fibers, filaments, fiber bundles, filament bundles.

Furthermore, in the context of the present invention, a reinforcement material is understood as meaning reinforcement fiber composites. Reinforcement fiber composites include non-crimp fabrics, woven fabrics and non-woven fabrics. These are defined as follows:

A fiber or filament is a linear, elementary structure formed from a fiber or filament material. The fiber or filament may be continuous or limited in length and is thin in relation to its length. To speak of a fiber or filament in the technical field, the ratio of length to diameter should be at least between 3:1 and 10:1.

Fiber bundles or filament bundles comprise fibers or filaments which essentially all extend in a longitudinal or axial direction, preferably over approximately an entire length of a control cable.

The fiber bundles or filament bundles can also extend over approximately 75% to 100% of the total length of the control cable. Rovings comprise at least two and preferably several fiber or filament bundles without twist or twist, which are arranged approximately parallel to one another.

Yarns comprise at least two and preferably several bundles of fibers or filaments with a twist, i.e. the bundles of fibers are arranged in a twisted manner.

A fiber or filament composite designed as a non-crimp fabric is a loose composite of fibers or filaments which preferably extend in space in the longitudinal and transverse direction and, if necessary, also in a third direction perpendicular to the longitudinal and transverse direction.

A fiber or filament composite designed as a fabric is a solid composite of fibers or filaments which preferably extend in space in the longitudinal and transverse direction and, if necessary, also in a third direction perpendicular to the longitudinal and transverse direction.

A nonwoven fabric is a structure of fibers or filaments of finite length, continuous fibers or filaments, or chopped yarns of any kind and origin, assembled in any way into a web (a layer of fibers or filaments, a web of fibers or filaments) and in any way with each other have been connected. Nonwovens are mostly flexible fabrics, i. H. they are easily pliable, their main structural elements are fibers or filaments, and they are relatively thin in thickness relative to their length and width.

The reinforcement material can be made of natural or synthetic materials such as glass, aramid or Kevlar®, ceramic, UHMWPE (Ultra High Molecular Weight Polyethylene), polyamide, polypropylene, PEEK, polyethylene terephthalate (PET), rayon (e.g. HL fibers), Dacron, vegetable fibers (e.g. silk, sisal, hemp, cotton, etc.), or spider silk fibers or mixtures thereof.

Aramid or Kevlar®, UHMWPE (Ultra High Molecular Weight Polyethylene), polyamide, polypropylene and spider silk fibers or combinations thereof are preferably provided as reinforcing fibers

This means that the properties can be varied in absolute terms and in their relationship between the longitudinal and transverse directions over a wide range.

Since metal wires are not used in magnetic resonance imaging (MRI) procedures due to the electrical conductivity of metal wires and the associated heating can be used, pull ropes made from pure aramid fiber bundles (Kevlar®) without matrix material and PEEK strands without matrix material are also used.

Kevlar® fibers or fiber bundles or PEEK strands are thus already known as control cables for MR-compatible medical devices, which, however, have an increased elongation compared to metal wires and therefore do not have a comparably low elongation under tensile load as metal wires. These mechanical disadvantages lead to problems in the handling and reproducibility of the handling of such medical devices.

An alternative to metal wires, Kevlar® fibers or fiber bundles or PEEK strands is provided with the MR-safe control cable according to the invention.

The MR-safer control cable according to the invention has improved mechanical properties, in particular a lower elongation, than, for example, Kevlar® fibers (without matrix material) and PEEK strands due to the above-described formation.

A particularly important factor is that the control cables have the lowest possible elongation, since control cables are usually subjected to tensile loads during operation. In contrast, elongation plays a subordinate role in rod-shaped bodies. The only thing that needs to be decided here is that they do not tear and can be completely removed from the human body.

A control cable can have a diameter of 1 mm, or less than 0.9 mm, or less than 0.8 mm, or less than 0.7 mm, or less than 0.6 mm, or less than 0.5 mm, or less than 0.4 mm or less than 0.3 mm, or less than 0.2 mm, or less than 0.1 mm, or less than 0.05 mm.

A control cable can have a diameter of 1 mm or greater than 0.9 mm or greater than 0.8 mm or greater than 0.7 mm or greater than 0.6 mm or greater than 0.5 mm or greater than 0.4 mm or greater than 0.3 mm or greater than 0.2 mm or greater than 0.1 mm or greater than 0.05 mm.

A control cable can therefore have a diameter of at least 0.02 mm or 0.05 mm or

0.1 mm or 0.2 mm or 0.3 mm or 0.4 mm or 0.5 mm and a maximum diameter of 0.6 mm or 0.7 mm or 0.8 mm or 0.9 mm or 1.0 mm or 1.1 mm (diameter from 0.02 mm to 1 mm). The control cable can preferably be produced by pultrusion and/or by extrusion.

In the context of the present invention, pultrusion is understood as meaning a process in which chemically reactive polymers/resins are crosslinked as the matrix material of the pultrudate.

Chemical reaction processes for pultrusion can be, in particular, radical or ionic cross-linking of polymers, such as unsaturated polyesters, etherification and esterification of polysaccharides, hydrolysis of polyvinyl esters, or acetalization of polyvinyl alcohol.

The matrix material can be doped with marker particles that produce artifacts in magnetic resonance imaging, so that the medical device is visible through these marker particles in magnetic resonance imaging, with the marker particles that produce artifacts in magnetic resonance imaging preferably essentially over the entire length of the Control cable are arranged so that the medical device is visible over its entire length in the magnetic resonance imaging.

The marker particles are embedded in the matrix material.

Although such marker particles can be made of metal, their proportion in the control cable is too small, so that the control cable is still classified as MR-safe. The marker particles are passive-negative MR markers, preferably selected from the following metals or metal compounds: iron (Fe), cobalt (Co), nickel (Ni), molybdenum (Mo), zirconium (Zr), titanium (Ti) , manganese (Mn), rubidium (Rb), aluminum (AI), palladium (Pd), platinum (Pt), chromium (Cr) or chromium dioxide (CrCh) or iron oxide (FeO, Fe203, Fe304).

MR-safe control cables according to the invention can thus be made visible in the MRT by the incorporation of small amounts of passive-negative MR marker particles, preferably by sharply defined artefacts.

Additionally or alternatively, the control cable can also have x-ray markers. The control cable can be made visible during X-ray examinations by means of embedded X-ray marker particles at a distal end of the control cable.

By providing an MR marker and/or an X-ray marker, the control cable or a medical device having at least one control cable is visible in magnetic resonance tomography and/or in X-ray examinations. By combining MR markers and X-ray markers, the control cables according to the invention can be made visible in both imaging methods at the same time.

The introduction of MR markers and/or X-ray markers into a medical device can be realized simply by using a correspondingly doped control cable. Control cables of this type can be mass-produced inexpensively with different dopings and with an exact dosage of the marker particles . When manufacturing a medical device, the use of one or more corresponding control cables with MR markers and/or X-ray markers can ensure that the medical device is visible in a magnetic resonance tomography and/or an X-ray examination.

The control cable can further comprise a central section and a peripheral section, which extend in the axial direction of the control cable, the central section being arranged centrally with respect to a cross section of the control cable and being radially surrounded by the peripheral section, and with both the central section and the peripheral section extend substantially over the entire length of the control cable, and the central section has at least one amplifying fiber embedded in a non-ferromagnetic matrix material, the matrix material being doped with MR marker particles, and the peripheral section having an undoped, non-ferromagnetic matrix material.

The diameter of the central section is preferably less than or equal to 0.2 mm, preferably less than or equal to 0.15 mm and even more preferably less than or equal to 0.1 mm and even more preferably less than or equal to 0.08 mm and in particular less than or equal to 0 .05mm. Due to the fact that only the matrix material of the very small central section is doped with MR marker particles, a particularly narrow and sharp artefact is produced in magnetic resonance tomography.

Such a concentrated arrangement of a smaller amount of MR marker particles is advantageous over that with a higher amount of MR marker particles distributed over the entire cross-section of the control cable because the voxels are blackened along the concentrated arrangement of MR particles, but these voxels have the same degree of blackness as with a larger quantity of MR marker particles, which is distributed over a correspondingly larger area. As a result, fewer voxels are blackened in width and a narrower image of the medical instrument is achieved, so that less target tissue can be covered by blackening in the MRT image. It is therefore possible with a control cable according to the invention with passive-negative MR marker doping only in the central section to generate an image in magnetic resonance tomography that is approximately as narrow as with a metal control cable in an X-ray imaging method.

This applies in particular when the control cable has only a single doped reinforcement fiber or in the case of a plurality of reinforcement fibers, with only the matrix material of the centrally arranged reinforcement fiber having MR markers. The reinforcement fiber provided with marker particles in the matrix material is then preferably arranged in the center of the control cable. This maximizes the distance between the doped central portion of the control cable and the surface of the medical device. As a result, water or fat molecules in the body to be examined cannot get any closer to the central section than the surface of the medical device. This keeps the resonance between the MR markers and the water or fat molecules small, whereby the artifacts generated by the MR markers are small and the medical device appears as a narrow strip in an MR imaging method.

In addition, it has been shown that due to the concentration of the MR markers on the central section, the proportion of MR markers in the matrix material can vary over a large range without this having a significant effect on the representation of the medical device in the MR imaging method. When using iron particles with a particle size of 0 to 20 μm, essentially the same representation was achieved with a weight ratio of about 1:5 to about 1:30 between marker and matrix material. It has been shown that the local concentration on an area that is as small as possible, i.e. the central section, has a much greater influence on the display in the MR imaging method than the proportion of marker particles in the matrix material.

With the invention, such thin control cables are created for the first time with a structure that can have a central section and a peripheral section.

A control cable is a one-piece solid body. It is not a tubular or hose-shaped hollow body.

In particular, the matrix material of the control cable is designed as a homogeneous matrix material. The matrix material of the peripheral section and of the central section thus preferably consists of the same type of material. ok

Preferably, the reinforcement material is arranged approximately uniformly in the peripheral portion with respect to the cross section. As a result, high torsional and flexural strength is achieved even with a thin or small-volume peripheral section.

It has also been shown that by concentrating on the central section, the total amount of MR marker is very small and very good imaging is nevertheless achieved. In this way, the best possible representation of a medical device comprising such a control cable with doping only in the central section is achieved.

A reinforcing fiber may comprise at least one elongate filament or multiple elongate filaments, and preferably multiple elongate filaments, arranged in parallel or intertwined or twisted. Due to the fact that the reinforcing fiber comprises at least one elongated fiber or several elongated fibers, the reinforcing fiber gives the control cable high strength in the longitudinal direction. A better product quality is achieved by such an ordered design and arrangement of the reinforcing fibers in the control cable.

The reinforcing fiber in the central portion may be an ht fiber bundle and the reinforcing fiber in the peripheral portion may be a glass fiber bundle.

An ht fiber bundle is a high-strength fiber bundle. Typical examples of ht fiber bundles are aramid fibers and UHMWPE fibers (Ultra High Molecular Weight Polyethylene Fibers). ht fiber bundles have a tensile or Tear strength of at least 20 cN/tex. Optionally, the ht fiber bundles have a tensile or tear strength of at least 32 cN/tex and in particular at least 30 cN/tex.

An ht fiber bundle is highly flexible and bendable and has a high tensile strength and tear strength. In addition, the ht fiber bundle embedded in the matrix material gives the control rope a certain rigidity.

Glass fiber bundles are stiffer than ht fiber bundles, so a control rope having both ht fiber bundles and glass fiber bundles is preferred. A control cable, which has both ht fiber bundles and glass fiber bundles, can be optimally adjusted with regard to its stiffness and flexibility and in particular with regard to its torsional stiffness. The arrangement of at least one glass fiber bundle in the peripheral section enables the highest possible rigidity. The at least one peripheral glass fiber bundle gives the control rope the necessary compression and bending stiffness for shear loading. Because at least one ht fiber bundle is arranged centrally on a neutral line, the at least one ht fiber bundle only minimally reduces the compression and bending stiffness of the control cable. The neutral line, also known as the zero line, is the layer of a cross-section of a control cable whose length does not change during a bending process in technical mechanics within the framework of elastostatics. There, the bend does not cause any tensile or compressive stresses. The area runs through the geometric center of gravity of the cross-sectional area of the control cable.

The at least one reinforcement fiber in the central section can also be a glass fiber bundle and the at least one reinforcement fiber in the peripheral section can be an ht fiber bundle. This arrangement is optimal when the control cable should have a low proportion of glass fiber and a high proportion of ht fibers. In this embodiment, a control cable consisting predominantly of the more flexible ht fiber is reinforced in compression and bending stiffness by the glass fibers.

It is advantageous to arrange the reinforcement fibers contained in the larger proportion on the surface of the control cable and the reinforcement fibers contained in the smaller proportion inside in order to obtain a homogeneous surface. This significantly increases the product quality. The proportion of reinforcing fibers in the interior is at least greater than 5% by volume or 10% by volume or 15% by volume or 20% by volume or 25% by volume or 30% by volume or 35% by volume or greater than 40% by volume.

The reinforcement fibers are electrically non-conductive fibers or filaments, so that they can be used during magnetic resonance imaging. Accordingly, the term reinforcing fiber as used in the present specification excludes any electrically conductive fiber such as thin metal wire or carbon filament.

A reinforcement fiber is preferably formed from a plurality of fibers. Such a fiber bundle is referred to as a "roving" in English.

When the fibers of the reinforcing fiber are twisted together, they form a yarn. Such a fiber bundle is referred to as "yarn" in English. All reinforcing fibers in the control cable can be ht fiber bundles. A control cable designed in this way has the best possible properties in terms of tear strength.

Furthermore, all of the reinforcing fibers in the control cable can be fiberglass bundles. Such a control cable has the best possible properties in terms of compression and flexural strength.

The non-ferromagnetic matrix material in the central portion and in the peripheral portion may be the same non-ferromagnetic matrix material. Epoxy resin is preferably provided as the matrix material.

The marker particles in the central section are preferably MR marker particles.

One or more reinforcement fibers can be provided in the central section and at least three or four or five or six or seven or eight or nine or ten can be arranged radially circumferentially around the reinforcing fiber of the central section and approximately equally spaced from one another in the peripheral section or eleven or twelve reinforcement fibers can be provided.

MR-safe control cables according to the invention are electrically non-conductive and do not heat up. Due to their design and material, they have good mechanical properties similar to those of metal wires. Due to the centric doping, the MR-safe control cables or medical devices containing such control cables can be imaged well in the MRI with a sharp artefact.

A control cable made of metal wire has very good mechanical properties. A control cable made from Kevlar® fibers or PEEK filaments, on the other hand, has poor mechanical properties in terms of tensile strength, yield point and modulus of elasticity, particularly with regard to elongation.

A control cable according to the invention made of a fiber bundle material can be structurally designed in such a way that a tensile strength is greater than that of a control cable made of Kevlar® fibers or PEEK filaments, and/or that a yield point is less than that of one made of Kevlar® fibers or PEEK filaments trained control cable, and / or that a modulus of elasticity is smaller than that of a control cable made of Kevlar® fibers or PEEK filaments.

Additionally, because the control cables of the present invention are made of non-metallic materials, they are electrically non-conductive and do not heat up and are therefore MR safe.

The mechanical properties (tensile strength, yield point and modulus of elasticity) of a control cable according to the invention are between those of a control cable made of metal wires and those of a control cable made of Kevlar® fibers or PEEK filaments. Depending on the composite material, it may also be possible to achieve better properties for individual parameters than with a metal wire.

In order to achieve less elongation and high strength in the longitudinal direction, the elongation at break and the tear strength of the control cable according to the invention are of the greatest importance.

This means that, due to the material composition used, a control cable according to the invention can have an elongation at break of a maximum of 4% or 3.5% or 3% or 2.5% or 2% or 1.5%. and 1% (4% to 1%).

This means that, due to the material composition used, a control cable according to the invention can have an ultimate tensile strength of at least 3.5 GPa or 4 GPa or 4.5 GPa to 5 GPa or 5.5 GPa and a maximum of 6 GPa (3.5 to 6.0GPa).

This means that, due to the material composition used, a control cable according to the invention can have a minimum tensile modulus (tensile strength; tensile modulus) of at least 75 GPa or 100 GPa or 125 GPa or 150 GPa or 175 GPa or 200 GPa (75 GPa to 200 GPa ) exhibit.

This means that a control cable according to the invention can have a minimum compression strength of 200 MPa or 250 MPa or 300 MPa or 400 MPa or 500 MPa to 600 MPa or 750 MPa or 1,000 MPa due to the material composition used exhibit.

A maximum compressive strength can be 1,500 MPa or 2,000 MPa or 2,500 MPa (200 MPa to 1000 MPa). This means that a control cable according to the invention can have a minimum modulus of elasticity of at least 75 GPa or 85 GPa or 90 GPa or 100 GPa due to the material composition used. A maximum modulus of elasticity can be a maximum of 115 GPa or 130 GPa or 140 GPa or 150 MPa (75 GPa to 150 MPa).

Advantages of the fiber composite materials according to the invention for the production of MR-safe control cables compared to control cables made of e.g. Kevlar® fibers or PEEK filaments are, among other things, a lower elongation under tensile load and/or a higher rigidity under shear load and/or a higher tear strength and thus a better , stable and reproducible control cable functionality that is closer to the control cable functionality of metal wires.

The control cable can be structurally designed in such a way that it can be arranged in one or more lumens in a casing wall and/or in a central lumen of a tubular medical device or in a lumen in a medical device that comprises a solid material body.

In order to improve the arrangement of the control cable in a lumen of a medical device, the control cable can have at least one attachment section and/or a deflection section, with knots or drivers (crimped on) being provided in the area of the attachment section, or the matrix material being provided at least in this area is designed to be weldable, and wherein the matrix material is designed to be more flexible in the area of the deflection section than in the rest of the control cable.

For these embodiments of a control cable according to the invention, matrix materials with a lower stiffness and/or greater flexibility than in the remaining area of the control cable are provided for the fastening section and/or the deflection section.

A particular material stress acts on the control cable at deflection sections if the control cable is arranged continuously from the proximal end via a deflection point at the distal end and running back to the proximal end.

In the area of the deflection section, the control cable can then have a higher sliding ability and/or flexibility than over the rest of its length. Furthermore, a thin hose or shrink hose made of a material with high lubricity, for example PTFE or FEP, can be applied or arranged on a surface of the control cable. A PTFE or FEP shrink tube can have a wall thickness of about 0.03 mm, 0.04 mm, 0.05 mm, 0.06 mm, 0.07 mm, 0.8 mm, 0.09 mm, 0.1 mm.

By providing such a hose or hose piece or section, an increased sliding ability of the control cable is achieved since the friction (or the friction coefficient) is reduced compared to that of the fiber composite material.

By providing a hose or a suitable coating of the control cable in the area of the deflection point(s), the friction in the bend is reduced and the fiber composite material is stabilized.

Lubricious materials can also be applied by extrusion, coating, dip coating, vapor deposition, and similar methods. Alternatively, this surface material could also be applied in-line using the pultrusion process, possibly in a second step in the manufacturing process.

When using a control cable according to the invention in a medical device, it can be provided that a control cable has to be deflected in order to fulfill a specific technical function. Such a section of the control cable, which is arranged in a medical device in the area of a deflection point for the control cable, in which the control cable is deflected, is referred to below as a deflection section.

In such a deflection point, higher mechanical loads can occur in a corresponding deflection section of a control cable as a result of bending, displacement and/or friction.

A control cable can have one or more deflection sections, which are arranged at a distance from one another in a longitudinal direction.

In a deflection section, the matrix material of the control cable is less rigid and/or more flexible than the matrix material of the remaining area of the control cable (main section). A preferred embodiment according to the invention of a control cable made of fiber composite material has a lower rigidity and/or higher flexibility in the deflection section. The deflection section comprises a section of the fiber composite material in the region of the deflection point of the medical device, in which the matrix material of the control cable has a lower rigidity and/or higher flexibility than the matrix material of the main section.

A matrix material with less rigidity and/or greater flexibility can be obtained by using a duroplastic with a lower Shore hardness, for example less than 46D or 39D or 29D or 25D or by less crosslinking of a reactive polymer/resin. In this case, it is most preferred to form a gradient in the matrix materials, so that there is no predetermined breaking point at the position of the matrix material change.

This can be achieved, for example, by changing the matrix material from epoxy resin to polyurethane.

Furthermore, a medical device with at least one control cable shown above is provided according to the invention.

The medical device may include or be formed from a solid body, such as a steerable guidewire. At least one control cable is provided in a central lumen in order to control a tip or a distal end of the guide wire.

The medical device according to the invention can comprise at least one tubular casing wall which delimits a lumen, with a control cable as described above being arranged in the lumen, in particular a central lumen and/or in at least one or more peripheral lumens formed in the casing wall.

The medical device may be a steerable catheter, a steerable ablation catheter, a steerable sheath, a stent ejection system, an occluder ejection system, a coil ejection system, an atrial flow regulator ejection system, a bioptome, a TAVR, TMVR & LAA delivery system, a thrombectomy system, a steerable guide wire or the like. In particular, the medical device can have two, three, four or more control cables.

Movement in two directions (two-dimensional) is possible by means of two control cables. If at least three or four control cables are provided, movement in four directions, i.e. in space (three-dimensional), is possible.

The control cable can have the fastening section at a distal end, with which the control cable is connected to the medical device at a distal end.

The control cable can be connected to the medical device as a material connection. The integral connection can be produced, for example, by welding or 3D printing or an additive manufacturing process.

A material connection is understood to mean all connections in which the connection partners are held together by atomic or molecular forces. At the same time, they are non-detachable connections, e.g. by means of welding, gluing, vulcanizing, which can only be separated by destroying the connection means.

For this purpose, the fastening section can additionally and/or alternatively have a suitable connection material or a suitable connection material can have been applied to the fastening section.

The connection of the control cable to the medical device can be designed as a form-fitting connection, which is formed by an interlocking of at least two connec tion means. As a result, the connection partners cannot become detached even without power transmission or when power transmission is interrupted.

The fastening section of the control cable can be designed as a first form-fitting connection means, such as rivets, screws, threaded connections, clips, locking elements, hooks, eyes, tabs or undercut-like connection means, or the fastening section can be a first separate form-fitting, if necessary, correspondingly designed detes, connecting means such as rivets, screws, threaded connections, clips, latching elements, hooks, eyes, straps or undercut-type connecting means.

A corresponding second positive connection means can be provided or formed at the distal end of the medical device. The first and the second connecting means are thus designed to form a form-fitting connection.

The connection of the control cable to the medical device can be designed as a non-positive connection in addition to and/or as an alternative to the positive connection. A normal force acts on the surfaces to be connected. Your mutual shift is prevented as long as the counter-force caused by the flap friction is not exceeded.

In this case, the fastening section of the control cable can be designed as a first non-positive connection means or the fastening section can have a first separate non-positive connection means.

A corresponding second non-positive connection means is provided or formed at the distal end of the medical device.

The first and the second connecting means can be designed to transmit shear and/or tensile forces.

An MR-safe control cable can be produced, for example, using a pultrusion process. A pultrusion process (also pultrusion process or pultruding) is a continuous manufacturing process for the production of fiber-reinforced plastic profiles, whereby the fibers are impregnated with a chemically reactive polymer in the pultrusion process, which is crosslinked (synonyms: polymerized, cured) in the subsequent course of the process. However, it is also possible to produce corresponding fiber-plastic-based control cables by means of extrusion, with the fibers being impregnated under pressure with heated, chemically non-reactive (already cross-linked) polymer. A system suitable for this purpose for producing a structured extrudate, comprising a special extrusion head, is described in WO 2017/037130.

The basic structure of a pultrusion system consists of a fiber rack, fiber guides, an impregnation device, a shaping tool and a hardening tool, a drawing device and, if necessary, a cutting unit.

In an open pultrusion process, the fibers or fiber bundles are fed via fiber guides from a (possibly multi-storey) coil store into a starting matrix material bath, i.e. the reactive polymer/resin material, the impregnation device. The fibers or fiber bundles can pass through one or more shaping tools so that they are brought to the desired profile shape. Mats, fabrics, scrims or fleeces can be integrated into the process at the fiber guides in order to adapt or optimize the mechanical properties compared to those of a purely unidirectional reinforcement, such as that achieved with fibers or fiber bundles.

In the so-called closed process, all of the fibers or fiber bundles first come into contact with the starting matrix material in the shaping tool, but then with increased pressure for better impregnation. The initial matrix material reacts in the flattening tool to form the crosslinked matrix material (polymer/resin). The partially or predominantly cured pultrudate is drawn through a caterpillar take-off, whereby the fibers or fiber bundles together with the starting matrix material are drawn from the impregnation device into the shaping tool and the curing tool.

Basically, a distinction can be made between the three methods of resin impregnation: tank method, pull-through method and injection method.

The tub process is the most common process for manufacturing pultruded profiles, especially with simple cross-sections. Impregnation takes place in an open source matrix material bath through which the dry fibers or fiber bundles are drawn. The fibers or fiber bundles are deflected into and out of the starting matrix material bath by guide screens.

The drawing process is used in particular in the manufacture of profiles with geometrically complex cross-sections. The fibers or fiber bundles are guided through the starting matrix material bath without being deflected, so that the impregnation device is passed through horizontally. On the inlet and outlet side of the bath with starting matrix material there are shaping tools that resemble the later profile shape. The starting matrix material scraped off by the fiber guides is collected under the impregnation device with the aid of a trough.

In the injection process, the fibers or fiber bundles are guided through the impregnation device without deflection, which has the shape of the profile to be produced and expands on the inside. The starting matrix material is injected into this cavity from both sides, perpendicular to the fiber direction. This process is used in the manufacture of simple profiles with high production volumes. In a tempered tool with a length of 0.5 m to 2.5 m, the final shaping of the profile and hot curing at temperatures between 100 °C and 200 °C then take place. The finished profile and thus the fibers or fiber bundles together with the starting matrix material are pulled through a subsequent drawing device, e.g. B. in the form of a caterpillar or pneumatic grippers, continuously conveyed and pulled out of the tool at a constant speed.

The drawing speed of the process is adjusted to the diameter of the profile, the complexity of the profile cross-section and the matrix material. A process speed of 0.1 m/min to 1.2 m/min is usual.

However, a pultrusion device for producing a pultrudate, in particular for producing an MR-safe control cable according to the invention, is preferably provided according to the invention. This comprises: at least one first coil device for feeding in reinforcement material, in particular at least one reinforcement fiber, a first pultrusion head comprising a first housing, the housing having a radially circumferential first side wall, and a first outlet nozzle and a first guide channel device is arranged at the rear end opposite to the direction of production, the space in the housing between the guide channel device, the side wall and the outlet nozzle delimiting a first impregnation space for impregnating the at least one reinforcing fiber with a starting matrix material, and the housing in Area of the impregnation chamber can be connected to a first feed device for the starting matrix material, and wherein at least one guide channel extending in the direction of production is formed in the guide channel device in order to at least introducing a reinforcement fiber from a device for feeding at least one reinforcement fiber into the impregnation chamber, and wherein the at least one guide channel is arranged approximately in a straight line with the outlet nozzle, the guide channel extending over the entire length of the guide channel device.

Within the scope of the present invention, the guide channel device can be designed as a quill similar to the quills for extrusion devices known from the prior art (in order to load a body with extrudate in a radially circumferential and uniform manner), to hit a body radially circumferentially and uniformly with starting matrix material.

According to the invention, the pultrusion head can also merely comprise a housing, a guide channel device with at least one guide channel and an impregnation space in order to apply matrix material to the reinforcing fibers, and an outlet nozzle.

A target diameter of the arrangement of the fibers to each other is defined according to the invention when it exits the guide channel or is determined by it.

A starting matrix material can be a reactive polymer or resin material and can comprise small non-crosslinked units or monomers. These monomers are not cured or polymerized or crosslinked in the starting matrix material.

An intermediate pultrudate can be a partially crosslinked or low-grade crosslinked matrix material, with this pultrudate having a certain rigidity.

A final pultrudate can be a highly crosslinked matrix material (polymer/flarz), although this is not necessarily completely crosslinked in the pultrudate. Optionally, an additional heat treatment of the pultrudate can be added after the pultrusion for further crosslinking and hardening of the matrix material.

The advantages of the pultrusion device according to the invention will be shown later using a pultrusion method according to the invention and apply analogously to the pultrusion device.

With the pultrusion device, a predefined and relatively precise geometric arrangement of one or more reinforcing fibers in the control cable is possible.

In order to achieve a stable, regular impregnation of one or more reinforcing fibers, a pultrusion head according to the invention is used in order to apply the starting matrix material to the reinforcing fibers at low pressure and to impregnate them essentially homogeneously.

The application of the starting matrix material by the pultrusion head avoids the deflection of the one or more reinforcing fibers and thus enables a better impregnation quality, since the one or more reinforcing fibers are exclusively linear. and that they are not pressed flat against the deflection rollers and the starting matrix material is not stripped off in an uncontrolled manner. The impregnation of the individual fibers is further improved by the application of pressure to the one or more reinforcing fibers with starting matrix material.

Furthermore, a device for feeding can be provided, which comprises at least one first coil device for feeding at least one reinforcement fiber.

The guide channel is preferably a central guide channel.

The first exit nozzle can have a nozzle disk with a nozzle opening for shaping an outer diameter of the impregnated reinforcing fiber.

In the direction of production, after the pultrusion head, there is a first felting device for low-grade crosslinking of the starting matrix material, as a result of which an intermediate pultrudate with a low-grade crosslinked matrix material and a certain rigidity is obtained.

Examples of crosslinking reactions are radical polymerizations of monomers with two vinyl functions or polycondensation or polyaddition using mono mers with two or more functionalities (e.g. in the case of phenolic plastics). The crosslinking of existing polymers is also referred to as crosslinking and can either be achieved via functionalities already present in the polymer through a clever choice of reaction conditions (self-crosslinkers) or by adding multifunctional, low-molecular substances, the crosslinking agents. Depending on the degree of crosslinking, crosslinking of polymers first produces elastomers and, with increasing crosslinking, thermosets.

In the direction of production, a second pultrusion head can be arranged after the flexing device. This comprises: at least one second coil device for supplying reinforcement material, in particular at least one reinforcement fiber, a second housing, the housing having a radially circumferential second side wall, a nozzle disk being arranged at a front end of the housing in the production direction and a guide channel device is arranged at the rear end opposite to the direction of production, the space in the housing between the guide channel device, the side wall and the outlet nozzle having a second impregnation chamber for impregnating the reinforcement fibers with an initial matrix material, and wherein the housing in the area of the impregnation chamber can be connected to a feed device for the initial matrix material, and wherein at least one second central guide channel, which extends in the production direction, is formed in the guide channel device in order to introducing pultrudate from the first heating device to the second impregnation chamber, and wherein the central guide channel is arranged approximately in a straight line to the outlet nozzle, wherein the central guide channel extends over the entire length of the guide channel device, and wherein at least one peripheral guide channel is provided, to introduce at least one second reinforcement fiber from a second device for feeding at least one reinforcement fiber into the second impregnation space, the peripheral guide channel being arranged next to the central guide channel t, the at least one peripheral guide channel extending the entire length of the guide channel means.

The nozzle disk can be designed to fix or define an outer diameter of the end pultrudate, preferably a control cable.

Optionally, a second nozzle disc can be provided after the pultrusion head in order to finally fix or readjust the outer diameter of the final pultrudate, preferably a control cable.

After the second pultrusion head, an arrangement element for arranging the intermediate pultrudate and the impregnated at least one second reinforcing fiber relative to one another can be provided.

In the production direction, after the second pultrusion head, there is a second heating device for a higher degree of crosslinking of the starting matrix material.

The first and/or the second pultrusion head can be connected to one or each to a pump for supplying the starting matrix material. In addition, each impregnation chamber can have a valve for discharging excess starting matrix material.

Furthermore, according to the invention, a pultrusion process for the production of a pultrudate, in particular a control cable, is provided. This includes the following steps: introducing a reinforcement material, in particular a reinforcement fiber, into a guide channel of a first pultrusion head,

Impregnation of the reinforcement fiber in a first impregnation chamber of the first pultrusion head with a starting matrix material, preferably with a starting matrix material doped with MR marker particles,

Forming an outer diameter for the starting matrix material during the exit from the first impregnation space by means of an exit nozzle,

heating to low-level crosslinking of the starting matrix material in a first heater,

obtaining an intermediate pultrudate,

introducing the intermediate pultrudate into a central guide channel of a second pultrusion head,

introducing at least one further reinforcement fiber into at least one peripheral guide channel of the second pultrusion head,

Impregnation of the at least one further reinforcement fiber in a second impregnation chamber of the second pultrusion head with a starting matrix material,

arranging the intermediate pultrudate and the impregnated reinforcing fiber relative to each other during exit from the second impregnation space by means of a nozzle disc, and

Heating and crosslinking of the matrix material to a higher degree in a second heating device.

In the prior art pultrusion processes, the central reinforcing fiber can fray and/or migrate from the central position after exiting the impregnation bath. or from the entry into the Fleizelement stabilization of the geo metric arrangement is no longer possible. This results in an uncontrolled spatial and/or linearly indeterminate off-center arrangement. In order to impregnate the reinforcing fibers with starting matrix material, these must also be deflected into the starting matrix material bath via rollers. This creates unilateral pressure on the reinforcing fibers, which impairs the flomogeneity of the impregnation and its geometrical arrangement. The multiple deflection of the reinforcing fiber can also cause twisting and tension in the pultrudate.

Alternatively, a pultrudate having a central portion and a peripheral portion may be made in two separate prior art sequential pultrusions. For this purpose, the central section is first produced as the first pultrudate and the matrix material is crosslinked to a higher degree, so that it achieves the usual rigidity. This first After curing, pultrudate is then introduced into a second, separate pultrusion as the central element, which is surrounded by further reinforcing fibers. The disadvantage is that the hardening of the first pultrudate creates a material boundary on the surface of the first pultrudate with the matrix material from the second pultrusion, resulting in a weak point in the material. This disadvantage is avoided by the consecutive pultrusion process according to the invention in a single pultrusion, since the intermediate pultrudate is only crosslinked to a low degree. In addition, a single consecutive pultrusion process is technically and economically advantageous because it can be performed at lower cost and in less time.

With the pultrusion method according to the invention, a significantly improved linearity and a significantly improved centering of the central doped section in the pultrudate in the longitudinal direction can be guaranteed than with a pultrusion method according to the prior art, in which the central section formed by the first reinforcing fiber deviates significantly from the zero line can.

The pultrudate may comprise a plurality of reinforcing fibers, with one reinforcing fiber preferably being arranged centrally and surrounded by a plurality of reinforcing fibers.

The intermediate pultrudate for the central section is first crosslinked to a low degree in order to prevent fraying of the reinforcing fibers and to achieve sufficient stiffness through the low degree of crosslinking, which enables a stable centric arrangement in the final pultrudate. In general, the better the geometric arrangement of the individual reinforcing fibers in a pultrudate, which is formed from a plurality of reinforcing fibers, the better the mechanical properties of a pultrudate.

In order to achieve an improved, stable geometric arrangement of all reinforcement fibers in the pultrudate and a stable, regular impregnation of all reinforcement fibers, a first and a second pultrusion head are provided in order to impinge the reinforcement fibers with low pressure without deflection in an impregnation device with starting matrix material and to impregnate them homogeneously. As a result, the individual reinforcing fibers are arranged in the pultrudate without the risk of the reinforcing fibers shifting or flattening out. The application of the starting matrix material by a pultrusion head avoids the deflection of the reinforcing fibers and also enables better impregnation quality because the reinforcing fibers are guided exclusively linearly and impregnated with pressure. The central reinforcement fiber is in the first pultrusion head, which includes a linear guide channel, impregnated with starting matrix material, which may contain marker particles, and in a second step passed through a first heating device in which the low-grade crosslinking of the starting matrix material takes place. This achieves a defined stiffness of the intermediate pultrudate. The pultrusion head contains a feed for starting matrix material, which is fed via a pump, for example, and a discharge for excess starting matrix material, it being possible for the excess starting matrix material to be fed back into the feed.

A nozzle disk can be arranged at the distal end of the first pultrusion head 1 to define the outer diameter (round) or the cross-sectional profile (shapes other than round) and to strip off excess starting matrix material.

In the third step, the intermediate pultrudate can be introduced into a central guide channel of a second pultrusion head. Peripheral reinforcing fibers can be introduced into peripheral guide channels of the second pultrusion head and loaded and impregnated with starting matrix material.

At the outlet of the second production head, which is distal in the direction of production, an arrangement element can be provided, which can be designed integrally or separately. This arrangement element defines the central arrangement of the intermediate pultrudate and the peripheral reinforcing fibers impregnated with starting matrix material in the pultrudate and wipes off excess starting matrix material.

The arrangement element contains openings, e.g., bores, which correspond to the desired geometric arrangement of the reinforcing fibers in the pultrudate. In the fourth step, this reinforcing fiber arrangement is introduced into a second heating element and the matrix material is crosslinked to a higher degree as it is passed through it.

According to the invention, pultrudates with changing matrix materials can be produced with the pultrusion device described above. Only one pultrusion head is required to produce a pultrudate without a central and peripheral section. In a pultrusion head according to the invention, the supplied starting matrix material can be changed quickly and in a controlled manner, so that changing sections (main sections, deflection section) can be produced with the first and second matrix material over defined lengths. For this purpose, one or more sufficiently small feed devices for the starting material and a correspondingly small impregnation space are provided, which be designed as a function of the diameter of the pultrudate to be produced and allow the starting matrix material to be changed quickly.

Exemplary embodiments of a control cable according to the invention are shown below.

According to a first exemplary embodiment, the control cable has a diameter of approximately 0.25 to 0.3 mm, for example. Only aramid fiber bundles are provided as fiber bundles. These have a fineness of at least about 6 Tex or at least about 22 Tex and preferably at least about 11 Tex. The matrix material is doped with MR marker particles.

In a second embodiment, the control cable has a diameter of, for example, 0.3 to 1 mm or approximately 0.3 mm or 0.2 mm or 0.3 mm or 0.4 mm to 0.5 mm mm to 0.6 mm or 0.7 mm or 0.8 mm 0.9 mm or 1 mm. Only aramid fiber bundles are provided as fiber bundles. These have a fineness of at least approximately 66 Tex or at least approximately 33 Tex, or at least approximately 22 Tex and preferably at least approximately 11 Tex. The matrix material is doped with MR marker particles.

In a third embodiment, one or more aramid fiber bundles of the control cable are arranged in the central section. The fiber bundles arranged in the peripheral portion are partly aramid, e.g. about 80% 65%, 50% 35% by volume and partly glass fiber bundles, e.g. about 20% 35% by volume. -%, 50% by volume 65% by volume. The diameter of the central portion is about 0.15 mm, 0.2 mm, 0.25 mm, 0.3 mm to 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, respectively mm. The larger the amount of fineness [Tex], the larger the diameter of the center portion. The control cable has a diameter of, for example, 0.3 mm or 0.4 mm or 0.5 mm or 0.6 mm to 0.7 mm or 0.8 mm or 0.9 mm or 1 mm. The matrix material is doped with MR marker particles.

In a fourth embodiment, one or more central aramid fiber bundles of the control cable are arranged in the central section and the matrix material of the central section is doped with MR marker particles. The aramid fiber bundles have a fineness of at least about 6 Tex or at least about 22 Tex and preferably at least about 11 Tex. The aramid fiber bundles arranged in the peripheral section, on the other hand, are embedded in non-doped matrix material. The diameter of the center section is about 0.07 mm to 0.15 mm. The larger the amount of fineness [Tex], the larger the diameter of the center ral section. The control cable has a diameter of approximately 0.25 to 0.3 mm, for example.

In a fifth embodiment, one or more aramid fiber bundles of the control cable are arranged in the central section and the matrix material of the central section is doped with MR marker particles. The fiber bundles arranged in the peripheral portion are partly aramid, e.g. about 80% 65%, 50% 35% by volume and partly glass fiber bundles, e.g. about 20% 35% by volume .-%, 50 vol .-% 65 vol .-%, which are embedded in non-doped matrix material. The diameter of the central portion is about 0.07 mm to 0.15 mm, about 0.1 mm to 0.2 mm, about 0.15 mm to 0.3 mm, and about 0.15 mm to 0.4 mm, respectively mm or about 0.15 mm to 0.50 mm or about 0.15 mm to 0.50 mm. The larger the amount of the fineness [Tex] of the aramid fiber bundles, the larger the diameter of the central portion. The control cable has a diameter of, for example, 0.25 to 1.00 mm or 0.3 mm or 0.4 mm or 0.5 mm or 0.6 mm to 0.7 mm or 0. 8 mm or 0.9 mm or 1 mm. The matrix material is doped with MR marker particles.

The above-mentioned embodiments of the present invention can be combined with one another as desired, insofar as this is technically possible.

Claims

patent claims

1. MRI-safe (MR-safe) control cable for controlling a medical device, wherein the control cable can be arranged in a medical device, wherein the control cable is formed from a non-ferromagnetic matrix material in which a reinforcing material is embedded, and wherein the control cable is structurally designed in such a way that the medical device can be controlled by moving the control cable in and against an axial direction of a medical device, or that a functional element of a medical device that can be coupled to the control cable can be controlled.

2. MR-safe control cable, in particular according to claim 1, characterized in that the control cable has at least one deflection section, wherein the deflection section is formed with matrix materials with a lower rigidity and/or higher flexibility than in the remaining area of the control cable.

3. MR-safe control cable according to claim 1 or 2, characterized in that the matrix material is doped with marker particles that produce artifacts in magnetic resonance tomography in such a way that the medical device is visible through these marker particles in magnetic resonance tomography, the in of the marker particles that produce magnetic resonance tomography artifacts are preferably arranged essentially over the entire length of the control cable, so that the medical device is essentially visible over its entire length in the magnetic resonance tomography and/or that the control cable has one or more X-ray markers.

4. MR-safe control cable according to one of claims 1 to 3, characterized in that that the control cable is constructed in such a way that it can be arranged in one or more lumens in a jacket wall and/or in a central lumen of a tubular medical device, and a diameter of 0.02 mm to 1 mm, ie 1 mm, or smaller 0.9 mm, or less than 0.8 mm, or less than 0.7 mm, or less than 0.6 mm, or less than 0.5 mm, or less than 0.4 mm, or less than 0.3 mm, or less than 0.2 mm or smaller than 0.1 mm, or smaller than 0.05 mm.

5. MR-safe control cable according to one of claims 1 to 4, characterized in that a structural configuration is achieved in that the matrix material is a duroplastic or a thermoplastic polymer, and / or that the reinforcing material has one or more reinforcing fibers, which as fibers, filaments, fiber bundles, filament bundles are formed, which preferably extend over approximately the entire length of the control cable, and/or that the control cable has an elongation at break of 4% to 1%, which is a maximum of 4% or 3.5% or 3% or 2.5% or 2% or 1.5% or 1%, and/or that the control cable has an ultimate tensile strength of 3.5 to 6.0 GPa at least 3.5 GPa or 4 GPa or 4.5 GPa or 5 GPa or 5.5 GPa and a maximum of 6 GPa.

6. MR-safe control cable according to one of claims 1 to 5, characterized in that the control cable has a central section and a peripheral section which extend in the axial direction of the control cable, the central section being arranged centrally with respect to a cross-section of the control cable and radially from the peripheral section is surrounded all around, and wherein both the central section and the peripheral section extend essentially over the entire length of the control cable, and the central section has at least one non-metallic reinforcement material embedded in a non-ferromagnetic matrix material, the matrix material having MR marker particles is doped, and the peripheral portion comprises an undoped, non-ferromagnetic matrix material.

7. Medical device with at least one MR-safe control cable according to one of claims 1 to 6.

8. Medical device according to claim 7, characterized in that that the medical device has a tubular casing wall which delimits a lumen, in particular a central lumen, the control cable according to one of claims 1 to 6 being arranged in the central lumen and/or in at least one or more peripheral lumens formed in the casing wall.

9. The medical device as claimed in claim 7 or 8, characterized in that the control cable has at least one fastening section at a distal end, via which the control cable is connected to a distal end of the tubular casing wall.

10. Pultrusion device for producing a pultrudate, in particular for producing an MR-safe control cable according to one of claims 1 to 6, comprising at least a first coil device for supplying reinforcement material, in particular at least one reinforcement fiber, a first pultrusion head comprising a first housing, wherein the The housing has a radially circumferential first side wall, and a first outlet nozzle is arranged at the front end of the housing in the production direction and a first guide channel device is arranged at the rear end opposite to the production direction, with the space in the housing between the guide channel device, the side wall and the Outlet nozzle delimits a first impregnation space for impregnating the at least one reinforcement fiber with a starting matrix material, and wherein the housing can be connected in the region of the impregnation space to a first feed device for the starting matrix material and wherein at least one guide channel extending in the direction of production is formed in the guide channel device in order to introduce at least one reinforcement fiber from a device for feeding at least one reinforcement fiber into the impregnation space, and wherein the at least one guide channel is approximately aligned in a straight line with the outlet nozzle angeord net, wherein the guide channel extends over the entire length of the guide channel means.

11. Pultrusion device according to claim 10, characterized in that in the production direction after the pultrusion head a first heating device is arranged for low-grade cross-linking of the starting matrix material, whereby an intermediate res pultrudate is formed with a low-grade crosslinked matrix material and a certain stiffness speed.

12. The pultrusion device according to claim 11, characterized in that a second pultrusion head is arranged downstream of the heating device in the production direction, comprising at least a second coil device for feeding in reinforcing material, in particular at least one reinforcing fiber, a second housing, the housing having a radially circumferential second side wall, with a nozzle disc being arranged at the front end of the housing in the production direction and a guide channel device being arranged at the rear end opposite to the production direction, the space in the housing between the guide channel device, the side wall and the outlet nozzle having a second impregnation space for impregnating the reinforcement fiber with an initial matrix material, and wherein the housing in the region of the impregnation chamber can be connected to a feed device for the initial matrix material, and wherein in the guide channel device With at least one second central guide channel extending in the production direction being designed to introduce the intermediate pultrudate from the first heating device into the second impregnation chamber, and with the central guide channel being arranged approximately in a straight line with the outlet nozzle, with the central guide channel extends over the entire length of the guide channel device, and wherein at least one peripheral guide channel is provided in order to introduce at least one second reinforcement fiber from a second device for feeding at least one reinforcement fiber into the second impregnation space, the peripheral guide channel being arranged next to the central guide channel is, wherein the at least one peripheral guide channel extends over the entire length of the guide channel means.

13. The pultrusion device as claimed in claim 12, characterized in that a second heating device for crosslinking the starting matrix material to a higher degree is arranged downstream of the second pultrusion head in the production direction.

14. A pultrusion method for producing a pultrudate, in particular an MR-safe control cable, according to any one of claims 1 to 6, comprising the following steps introducing a reinforcement material, in particular a reinforcement fiber, into a guide channel of a first pultrusion head,

obtaining an intermediate pultrudate,

15. Control cable according to one of claims 1 to 6 produced by a pultrusion process according to claim 14.