Magnetic catheter, intervention device and catheter intervention method

Abstract

The invention discloses a magnetic catheter, an intervention device and a catheter intervention method.The magnetic catheter comprises an inner-layer tube and an outer-layer tube which are arranged in a nested mode to form the inner diameter and the outer diameter of the magnetic catheter, a middle layer is fixedly embedded between the inner-layer tube and the outer-layer tube, and the middle layer is an elastic layer and can be bent in the circumferential direction; the thrust effect can be transmitted and delivered along the axial direction; the magnetic part and the developing part are both arranged at the front end of the magnetic catheter in the advancing direction, the magnetic part has single polarity, and the developing part is used for improving the detectability of the magnetic catheter under rays. The inner-layer tube, the outer-layer tube and the middle-layer structure are combined to form a main body structure of the magnetic catheter, so that the catheter has supporting performance, pushing performance and bending adjusting performance, meanwhile, through the magnetic part and the developing part, the end of the catheter can be clearly observed, a non-contact magnetic field force turning effect is provided for the catheter, and the magnetic catheter can be conveniently used. The compatibility of the magnetic catheter is improved, the operation convenience is improved, and the operation difficulty of the operation is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of medical equipment, and in particular to a magnetic catheter, an intervention device and a catheter intervention method. Background Art

[0002] Vascular interventional surgery is widely used to treat vascular diseases in various parts of the body, such as coronary arteries, thoracic aorta, femoral artery, vena cava, etc., due to its advantages of low trauma and good prognosis. However, the current interventional treatment of intracranial blood vessels, also known as neurovascular vessels, is limited by the small diameter of intracranial blood vessels, long and tortuous paths, and has high surgical risks and greater operational difficulties, making vascular interventional surgery difficult to popularize. During current interventional surgeries, medical catheters are required to achieve the dual functions of reaching the lesion site and providing instrument access. Traditional catheters include structural parts such as linings, braids, and extruded tubes. Catheters used for neurointervention are limited by the complex vascular structure and need to have a contour structure with variable stiffness to maintain good trackability and torque transmission in tortuous neurovascular vessels. Existing catheters usually have complex structures and maneuvers, and often require auxiliary components such as guidewires and intermediate catheters to achieve turning and advancement. Not only will it make it difficult for the catheter to adapt to the complex vascular environment, but it also has poor flexibility and is difficult to achieve multiple accurate deflections. In the complex structure of neurovascular vessels, once the tracking and torque control does not meet expectations, it is very easy to cause the catheter to bend and deform, resulting in the severance of the access, affecting the progress of the operation. In severe cases, it may even damage the blood vessels and cause more serious medical accidents.

[0003] Therefore, how to provide a catheter structure suitable for intracranial blood vessels so as to treat intracranial vascular lesions through interventional surgery is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0004] In view of this, an object of the present invention is to provide a magnetic catheter, an interventional device and a catheter intervention method, so that the magnetic catheter is suitable for the environment of intracranial blood vessels and can treat intracranial vascular diseases through interventional surgery.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] In a first aspect, an embodiment of the present invention provides a magnetic catheter, comprising:

[0007] The inner tube and the outer tube are nested to form the inner diameter and the outer diameter of the magnetic conduit, and an intermediate layer is embedded and fixed between the inner tube and the outer tube, and the intermediate layer is an elastic layer that can be bent in the circumferential direction and can transmit thrust in the axial direction;

[0008] The magnetic part and the developing part are both arranged at the front end of the magnetic catheter in the traveling direction. The magnetic part has a single polarity, and the developing part is used to improve the detectability of the magnetic catheter under radiation.

[0009] Preferably, in the above-mentioned magnetic conduit, the intermediate layer includes a first intermediate layer and a second intermediate layer, the first intermediate layer is a metal spring mesh, the second intermediate layer is a metal woven mesh, the first intermediate layer and the second intermediate layer are both cylindrical structures and are concentrically sleeved and fixed, and the first intermediate layer and the second intermediate layer have a constant winding density.

[0010] Preferably, in the above-mentioned magnetic conduit, the second intermediate layer penetrates the conduit axially, the first intermediate layer is shorter than the second intermediate layer, and the annular area of ​​the magnetic conduit where the magnetic portion is arranged only includes the second intermediate layer.

[0011] Preferably, in the above-mentioned magnetic conduit, the intermediate layer includes a third intermediate layer and a fourth intermediate layer, the third intermediate layer is a metal spring mesh, the fourth intermediate layer is a metal woven mesh, the third intermediate layer is a stepped cylindrical structure with a variable cross-section along its axial direction, and the winding density in the cylindrical area with a uniform radius is constant; the fourth intermediate layer is also a stepped cylindrical structure with a variable cross-section along its axial direction, and the winding density in the cylindrical area with a uniform radius is constant.

[0012] Preferably, in the above-mentioned magnetic catheter, the middle layer is a single-layer structure, and the material of the middle layer is polymer fiber, metal spring mesh, metal braided mesh, hypotube or combined ring.

[0013] Preferably, in the above magnetic catheter, the inner tube is a tubular structure made of one or more of polytetrafluoroethylene, polyolefin and polyethylene through extrusion, dip coating sintering or powder sintering, and the wall thickness of the inner tube is 0.005mm-0.2mm.

[0014] Preferably, in the above magnetic conduit, the inner tube is a tubular structure with a uniform inner diameter, or,

[0015] The inner tube is a variable cross-section structure with an inner diameter that changes evenly and continuously or changes in a gradient, and the end with the smallest inner diameter of the inner tube faces the front end of the magnetic conduit in the traveling direction.

[0016] Preferably, in the above magnetic catheter, the outer tube is composed of one or more materials of polyamide, polyether block amide, polyurethane, and polyolefin.

[0017] Preferably, in the above-mentioned magnetic catheter, the outer layer tube includes at least two sections of a first outer layer tube and a second outer layer tube. The first outer layer tube and the second outer layer tube are spliced ​​and fixed in the axial direction of the outer layer tube and cover the inner layer tube and the middle layer. The hardness of the first outer layer tube is less than that of the second outer layer tube, and the first outer layer tube is arranged closer to the front end of the magnetic catheter in the traveling direction than the second outer layer tube.

[0018] Preferably, in the above-mentioned magnetic conduit, the splicing area of ​​the first outer tube and the second outer tube is a staggered tooth-shaped structure, and the splicing area is fixed into an integral structure by melting and diffusion.

[0019] Preferably, in the above magnetic catheter, the outer side of the outer tube at the front end position of the magnetic catheter in the traveling direction is coated with one or more coatings for reducing the surface friction coefficient in a water-based liquid environment.

[0020] Preferably, in the above magnetic conduit, the magnetic portion is a ring structure and is fixedly disposed on the magnetic conduit, or,

[0021] The magnetic part is metal powder particles and is pre-mixed in the outer tube at a volume fraction of 10% to 80%, or,

[0022] The magnetic part is a mixed structure of a metal ring and metal powder particles, and the metal ring and the metal powder particles have the same polarity.

[0023] Preferably, in the above-mentioned magnetic catheter, the material of the magnetic part is one or more of neodymium iron boron alloy, samarium cobalt alloy, samarium iron nitrogen alloy, aluminum nickel cobalt alloy and ferrite.

[0024] Preferably, in the above-mentioned magnetic conduit, the developing portion is attached to the magnetic conduit in the form of a ring or powder.

[0025] In a second aspect, an embodiment of the present invention provides an interventional device, which includes the magnetic catheter described in any one of the above embodiments, and also includes a magnetic field generating component, the magnetic field generated by the magnetic field generating component covers the operating area of ​​the magnetic catheter, and generates an attractive force or a repulsive force on the magnetic part on the magnetic catheter to deflect the magnetic catheter.

[0026] In a third aspect, an embodiment of the present invention provides an intervention method, wherein the intervention method uses the intervention device provided in the above embodiment to perform the intervention of the magnetic catheter in the blood vessel, and the catheter intervention method comprises at least the following steps:

[0027] Pushing the catheter: Pushing the catheter at the end of the magnetic catheter, driving the front end of the magnetic catheter to move in the blood vessel through the support of the middle layer, and displaying the position of the front end of the magnetic catheter in the blood vessel through the developing part;

[0028] Adjust the direction: At the entrance of a blood vessel with a large curvature, a magnetic field parallel to the target blood vessel path is applied through a magnetic field generating component, and the magnetic part of the magnetic catheter is twisted by force, and the front end of the magnetic catheter is driven to deflect in the direction of the target path;

[0029] Catheter advancement: After the front end of the magnetic catheter completes deflection, the end of the magnetic catheter continues to be pushed outside the body. The magnetic catheter runs along the target blood vessel under the guidance of the magnetic part. When the path in this direction is completed and encounters the entrance of a subsequent blood vessel with a larger degree of curvature, the direction adjustment steps are repeated to make the magnetic field parallel to the subsequent blood vessel, and drive the magnetic catheter to complete the turn and enter the subsequent blood vessel.

[0030] Preferably, in the above-mentioned intervention method, in the direction adjusting step, two magnetic field generating components are provided, and the two magnetic field generating components cooperate to apply magnetic force to drive the magnetic portion and the front end of the magnetic catheter to deflect.

[0031] It can be seen from the above technical scheme that the magnetic catheter provided by the present invention is composed of an inner tube, an intermediate layer, and an outer tube as the main structural basis, so that the magnetic catheter has support, pushing, and flexibility, and the combined structural design of the intermediate layer makes the magnetic catheter as a whole have extremely strong transmission and high sensitivity to the force applied to the end outside the body, thereby improving the control performance of the magnetic catheter; at the same time, the setting of the magnetic part enables the magnetic catheter to be deflected through non-contact magnetic field force, so that the magnetic catheter has excellent bending ability, which greatly facilitates the process of the magnetic catheter crossing tortuous blood vessels and reaching the specified position, reduces or even eliminates the dependence of traditional catheters on auxiliary equipment such as guide wires and intermediate catheters, reduces the difficulty of operation, reduces the operation time, and provides more possibilities for emergency rescue. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 A schematic diagram of a cross-sectional structure of a magnetic catheter provided in an embodiment of the present invention;

[0034] Figure 2 for Figure 1 Schematic diagram of the structure of the first intermediate layer;

[0035] Figure 3 for Figure 1Schematic diagram of the structure of the second intermediate layer;

[0036] Figure 4 for Figure 1 Detailed view of the front structure of the magnetic catheter;

[0037] Figure 5 It is a schematic diagram of the variable cross-section structure of the middle layer and the inner layer tube;

[0038] Figure 6 It is a schematic diagram of the multi-section splicing structure of the outer tube;

[0039] Figure 7 A schematic diagram showing that the magnetic part is a metal ring structure and a plurality of them are arranged at intervals;

[0040] Figure 8 It is a schematic diagram of a structure in which a magnetic part is a metal ring and metal powder particles are used simultaneously;

[0041] Fig. 9 A schematic diagram of a structure in which the magnetic part and the developing part are integrated into a composite ring structure and multiple groups are arranged;

[0042] Fig.10 Schematic diagram of the middle layer using a hypotube structure;

[0043] Fig.11 Schematic diagram of the hypotube structure;

[0044] Fig.12 It is a schematic diagram of a multi-segment structure of a hypotube;

[0045] Figure 13-14 Schematic diagram of the movement of the magnetic catheter in the blood vessel.

[0046] Among them, 10-inner tube; 20-outer tube; 210-first outer tube; 220-second outer tube; 230-third outer tube; 240-fourth outer tube; 30-middle layer; 310-first middle layer; 320-second middle layer; 330-third middle layer; 340-fourth middle layer; 350-hypotube; 40-magnetic part; 410-metal ring; 420-metal powder particles; 50-developing part; 60-composite ring; 70-magnetic conduit; 80-magnetic field generating component. DETAILED DESCRIPTION

[0047] The core of the present invention is to disclose a magnetic catheter, an interventional device and a catheter interventional method, so that the magnetic catheter is suitable for the environment of intracranial blood vessels and can treat intracranial vascular lesions through interventional surgery.

[0048] In order to make the technical personnel in this field better understand the scheme of the present invention, the embodiments of the present invention are described below with reference to the accompanying drawings. In addition, the embodiments shown below do not limit the content of the invention recorded in the claims. In addition, the entire contents of the structures represented by the following embodiments are not limited to those necessary for the solutions of the invention recorded in the claims.

[0049] like Figure 1-4 As shown, the magnetic catheter provided by the embodiment of the present invention mainly includes an inner tube 10, an outer tube 20, an intermediate layer 30, a magnetic part 40 and a developing part 50, wherein the inner tube 10 is an ultra-thin polymer layer with uniform diameter and thickness, so as to provide a uniform and complete inner cavity structure for the catheter, thereby providing a good channel for the passage of subsequent medical devices. The outer tube 20 is sleeved on the outside of the inner tube 10 at intervals to protect the inner tube 10 and constitute the outer diameter structure of the magnetic catheter. The thickness of the outer tube 20 is set according to demand, and a coating layer can be set according to the use scenario to enhance the smoothness of the movement of the magnetic catheter and the safety of use in the blood vessel, and reduce the body's rejection reaction. The middle layer 30 is embedded between the inner tube 10 and the outer tube 20, and is fixedly connected to the inner tube 10 and the outer tube 20 to form the main structure of the magnetic conduit. The middle layer 30 is an elastic layer that can be bent along the circumferential direction and can transmit thrust along its axial direction, that is, when the middle layer 30 is subjected to thrust at one end, it can be transmitted to the other end and make the other end move, and the moving end can realize turning under the action of external force.

[0050] On the basis of the above structure, the magnetic part 40 and the developing part 50 are both arranged at the front end of the magnetic catheter in the direction of travel. It should be noted that the magnetic part 40 and the developing part 50 can be arranged at the boundary area between any layer or two layers of the inner tube 10, the outer tube 20 and the middle layer 30, wherein the developing part 50 is used to improve the detectability of the front end (hereinafter referred to as the "front end") of the magnetic catheter in the direction of travel under the radiation, so that the position of the magnetic catheter can be smoothly observed in a more complex vascular environment. The magnetic part 40 has a single polarity, which can be displaced or rotated under the action of the magnetic field force, thereby driving the front end of the magnetic catheter to rotate. When it is necessary to pass through a turn, the magnetic part 40 is driven by an external magnetic field to drive the front end of the magnetic catheter to turn backward, and then the end of the magnetic catheter is pushed to realize the turning and advancement of the magnetic catheter in the blood vessel. In the above structure, the magnetic catheter does not need to be provided with an external adjustment structure such as a control guide wire. The magnetic portion 40 and the developing portion 50 cooperate to accurately display the position of the front end of the magnetic catheter, thereby achieving convenient adjustment. The simplification of structural components can also reduce the volume occupied by the magnetic catheter in the blood vessel, thereby reducing the risk of damaging the blood vessel during surgery.

[0051] Furthermore, in the magnetic conduit provided in the embodiment of the present invention, the intermediate layer 30 can be provided with one or more layers according to the strength requirements. In a specific embodiment of the present invention, for example Figure 1 and Figure 4 As shown, the intermediate layer 30 includes a first intermediate layer 310 and a second intermediate layer 320. The first intermediate layer 310 and the second intermediate layer 320 are both cylindrical structures and are concentrically sleeved and fixedly connected as an integral structure. In order to meet the elasticity requirements of the intermediate layer 30, the first intermediate layer 310 is a metal spring mesh, which can be made by connecting nickel-titanium wires with a circular cross section and is arranged close to the inner tube 10 on the inner side; and the second intermediate layer 320 is a metal braided mesh, which can be made of a plurality of stainless steel square wires with an aspect ratio greater than 1:1, such as 16 square wires with an aspect ratio of 3:1 in a 1×2 braiding manner, and the second intermediate layer 320 is arranged on the outer side of the first intermediate layer 310. And preferably, in order to maintain the strength stability of the first intermediate layer 310 and the second intermediate layer 320, the first intermediate layer 310 and the second intermediate layer 320 both have a constant winding density. In the above embodiment, the first intermediate layer 310 made of the metal spring mesh has a good radial support effect, while the second intermediate layer 320 made of the metal woven mesh can have stable bending control operability. The cooperation between them can realize the support of the intermediate layer 30 for the overall performance of the magnetic catheter body.

[0052] Based on the above embodiment, the lengths of the first intermediate layer 310 and the second intermediate layer 320 in the axial direction of the magnetic conduit can be the same to achieve alignment and fit between the first intermediate layer 310 and the second intermediate layer 320. Similarly, the first intermediate layer 310 and the second intermediate layer 320 can also be different in length to enable different regions of the magnetic conduit to have different structural strengths. Figure 4 As shown, the structure of the second intermediate layer 320 penetrates the entire magnetic catheter in the axial direction, while the structure of the first intermediate layer 310 located inside the second intermediate layer 320 does not completely penetrate the entire magnetic catheter structure, and the front end area of ​​the magnetic catheter only includes the second intermediate layer 320, and preferably the area of ​​1cm-50cm at the front end of the catheter only contains the second intermediate layer 320. In the above structure, the magnetic catheter only includes the area of ​​the second intermediate layer 320, the second intermediate layer 320 is arranged in contact with the inner tube 10, and the front end has stronger flexibility and lower bending modulus than other areas of the magnetic catheter, so that the magnetic catheter is easier to bend and deflect in the human blood vessel under the drive of the magnetic part 40.

[0053] It should be noted that in the above-mentioned embodiment, in the area of ​​the magnetic catheter that only contains the second intermediate layer 320 structure, the second intermediate layer 320 can be a continuous structure or a segmented structure. For example, in a specific embodiment of the present invention, the second intermediate layer 320 is not continuous, and part of the second intermediate layer 320 is interrupted, and it runs through the entire magnetic catheter. This structure can further improve the flexibility of the front end of the magnetic catheter, reduce the bending modulus, and facilitate the bending and deflection of the catheter in the human blood vessel. It should be noted that the above-mentioned embodiment can also improve the flexibility of the front end of the magnetic catheter and reduce the bending modulus through the first intermediate layer 310 running through the entire magnetic catheter, and through the non-penetrating structure of the second intermediate layer 320, which will not be repeated here.

[0054] In addition, it should be noted that Fig.10 and Fig.11 As shown, part of the first intermediate layer 310 at the front end of the magnetic catheter can also be replaced by a sea wave tube 350 structure. The sea wave tube 350 uses a metal tube and is carved with multiple groups of symmetrical patterns with a spacing of 0.01mm-0.5mm to form a pseudo spring net structure. The sea wave tube 350 does not have the elastic structure and elongation performance of the traditional spring net in its axial direction, but has good flexibility in its radial direction, which can prevent the traditional spring net from being stretched and deformed by force, and greatly facilitate the bending deformation in the axial direction, thus meeting the mechanical performance requirements of the front end of the magnetic catheter. Preferably, a nickel-titanium alloy tube is used as the base material of the sea wave tube 350. It should also be noted that the sea wave tube 350 is a structure attached to the front end of the magnetic catheter, and it can be attached to the end of the magnetic catheter through a complete sea wave tube 350 structure, such as Fig.12 As shown, it can also be composed of a plurality of interrupted discontinuous hypotubes 350 with a constant gap of 0.01mm-0.5mm attached to the front end of the catheter to provide a similar function.

[0055] Furthermore, in some other embodiments of the present invention, Figure 5As shown, the intermediate layer 30 includes a third intermediate layer 330 and a fourth intermediate layer 340, wherein the third intermediate layer 330 is a metal spring mesh structure, and the fourth intermediate layer 340 is a metal woven mesh structure, and the fourth intermediate layer 340 is arranged on the outside of the third intermediate layer 330, as in the above-mentioned embodiment. In particular, the third intermediate layer 330 is a stepped cylindrical structure with a variable cross-section along its axial direction. It should be noted that the stepped cylindrical structure with a variable cross-section can be abrupt or gradual; the gradual transition can be a uniform transition or a parabolic transition; and the parabolic transition can be an upper convex shape transition or a lower convex shape transition. At the same time, the winding density of the third intermediate layer 330 in the cylindrical area with uniform radius is constant, while the winding density in the cylindrical area with different radius is different. Correspondingly, the fourth intermediate layer 340 is also a stepped cylindrical structure with a variable cross-section along its axial direction, so that it can be smoothly mounted on the outside of the third intermediate layer 330, and the fourth intermediate layer 340 also has a constant winding density only in the cylindrical area with uniform radius.

[0056] Specifically, in some embodiments of the present invention, the third intermediate layer 330 is a metal spring mesh made of square nickel-titanium wire with a cross-sectional aspect ratio greater than 1:1, and the third intermediate layer 330 adopts a winding gap of 0.3mm-0.6mm in the 1mm-500mm area close to the front end of the magnetic conduit, and adopts a winding gap of 0.1mm-0.3mm in the remaining area close to the end of the magnetic conduit. It should be noted that the third intermediate layer 330 of a two-stage stepped sleeve structure is used for illustration here. When the third intermediate layer 330 is a multi-stage structure, the winding gap of each section can be linearly reduced from the front end to the end of the magnetic conduit, so that the front end of the magnetic conduit has better flexibility and deformation, and the end has better thrust support effect.

[0057] Furthermore, in the magnetic catheter provided in the embodiment of the present invention, the middle layer 30 can also be a single-layer structure, and it should be noted that no matter whether the middle layer 30 is a single-layer or multi-layer structure, each layer structure is a combination of one or more of polymer fibers, metal spring mesh, metal braided mesh, hypotube 350 and combination ring, so that the middle layer 30 has good elasticity and support effect, and can achieve movement and bending in the blood vessel. And the middle layer 30 can only exist locally in a certain section of the magnetic catheter, or be set throughout the entire magnetic catheter.

[0058] It should be noted that when the middle layer 30 is a polymer fiber, it is composed of one or more axially arranged silk threads of polyester fiber or polytetrafluoroethylene fiber, and is adhered to the inner tube 10 by gluing or melt bonding; and when the middle layer 30 is a metal spring mesh, it is a single or multiple strands of metal filaments made of one or more sizes of stainless steel alloy or nickel-titanium alloy, which are wound on the inner tube 10 with a certain tension and pitch. The metal filaments can be cylindrical filaments or square flat wires with a length-to-width ratio greater than 1:1, and within a certain length range, the tension of the metal spring mesh is constant, but the pitch is gradual.

[0059] In addition, when the middle layer 30 is a metal braided mesh, it is made of metal filaments made of stainless steel alloy or nickel-titanium alloy of one or more sizes, in a certain number and a certain type of braiding method, and attached to the inner tube 10; the metal filaments can be cylindrical filaments or square flat wires with a length-to-width ratio greater than 1:1, and preferably, the number of metal filaments used is 8, 12, 16, 20 or 24, in a 1×1, 1×2 or 2×2 braiding method. When the middle layer 30 is a sea wave tube 350 or a combination ring, it can be a gradual structure with a certain size gradient in width or gap, preferably, the width of the metal support is gradually changed in a gradient of 0.01μm-100μm, and the gap is also gradually changed in a gradient of 0.01μm-100μm.

[0060] In the magnetic catheter provided in the embodiment of the present invention, the inner tube 10 is preferably an ultra-thin tube made by extrusion, dip-coating sintering or powder sintering, so as to have a good integrated structure to meet the support and channel providing effects. At the same time, the material of the inner tube 10 is preferably composed of one or more of polytetrafluoroethylene, polyolefin, and polyethylene. The above materials are commonly used medical materials, have good medical properties and reduce the occurrence of body rejection reactions. In order to avoid the bloated structure of the magnetic catheter and make it difficult to move in the blood vessel, the wall thickness of the inner tube 10 is 0.005mm-0.2mm. According to the commonly used pipeline size requirements, the inner tube 10 can be set as a structural member with a thickness of 0.01mm, 0.015mm and 0.02mm according to the surgical needs and the matching instruments.

[0061] It should be further explained that in the magnetic catheter provided in the embodiment of the present invention, Figure 1 As shown, the inner tube 10 can be a tubular structure with a uniform inner diameter in the length direction of the magnetic conduit, so as to facilitate production and installation. Figure 5As shown, the inner tube 10 can also be a variable cross-section structure with an inner diameter that changes uniformly and continuously or changes in a gradient, such as a truncated cone structure, or a tubular structure with a stepped configuration, and the end of the inner tube 10 with the smallest inner diameter faces the front end of the magnetic catheter in the direction of travel, so that the magnetic catheter has a good suction function. In a specific embodiment of the present invention, within the range of 1cm-50cm at the front end of the magnetic catheter, the inner tube 10 is a cylindrical structure with a radius of a first inner diameter, and in the area beyond the range of 1cm-50cm at the front end of the magnetic catheter, the inner tube 10 is a cylindrical structure with a radius of a second inner diameter, and the value of the second inner diameter is greater than the first inner diameter; at this time, the inner tube 10 needs to use a special shape, that is, a step-configuration support structure as a mold during production, and in this embodiment, a PTFE material using a dip-coating and sintering process is used to form an inner tube 10 with uniform thickness but variable inner diameter on the surface of a mandrel with a stepped configuration. The structure of the inner tube 10 causes a gradient change in the inner diameter of the inner cavity of the magnetic catheter, so that when the magnetic catheter is in a negative pressure working environment such as thrombus aspiration, a greater suction force can be obtained with the same vacuum degree, thereby improving the thrombus aspiration effect. In addition, the reduction in the inner diameter of the inner cavity at the front end of the magnetic catheter can also significantly improve the flexibility of the magnetic catheter, enhance the bending and deformation ability of the magnetic catheter, and reduce the difficulty of its bending in the blood vessel.

[0062] It should be noted that the inner tube 10 may also have a sudden change at one or more positions along its length, or a structure with a gradual change in taper and length at a certain position along its length.

[0063] Furthermore, in the magnetic catheter provided in the embodiment of the present invention, the outer tube 20 is composed of one or more materials of polyamide, polyether block amide, polyurethane, and polyolefin, and it should also be noted that the outer tube 20 can be a single-segment complete tubular structure, or it can be composed of multiple sections of tubular structures spliced ​​together. In some embodiments of the present invention, the outer tube 20 is composed of polymer extrusion tubes of different materials, which at least includes a first outer tube 210 and a second outer tube 220. The first outer tube 210 and the second outer tube 220 are fixedly spliced ​​in the axial direction of the outer tube 20 and cover the inner tube 10 and the middle layer 30. On this basis, the first outer tube 210 and the second outer tube 220 can be produced separately and then assembled and connected. In addition, it should be noted that the hardness of the first outer layer tube 210 is preferably smaller than that of the second outer layer tube 220, and the first outer layer tube 210 is arranged closer to the front end of the magnetic conduit in the traveling direction than the second outer layer tube 220, so that the front end hardness of the magnetic conduit is lower and has better bending performance.

[0064] Based on the above embodiments, Figure 5 and Figure 6As shown, the outer tube 20 may also be provided with a third outer tube 230 and a fourth outer tube 240 to form a total of four sections of structure in cooperation with the first outer tube 210 and the second outer tube 220. Specifically, the four sections of structure are made of polymer extruded tubes of different materials and spliced ​​together, and it should be noted that the four sections of polymer extruded tube structure are arranged in the order of polyolefin-thermoplastic polyurethane-polyether block amide-polyamide from the front end to the rear end of the magnetic conduit, so that the hardness of the magnetic conduit is gradually increased from the front end to the rear end, so that the rear end of the magnetic conduit has a good thrust transmission effect, and the front end has a good turning performance.

[0065] It should be noted that the above embodiment only describes the structure of the outer tube 20 made of four sections of polymer extruded tubes. The number of sections of different materials used in practice will be appropriately adjusted according to the production of magnetic conduits of different specifications and models. The number of spliced ​​sections of the outer tube 20 is generally not less than 2 sections and not more than 12 sections. The thickness of the polymer extruded tube used to make the outer tube 20 is 0.03mm-0.2mm.

[0066] It should be noted that the thickness and length of each section of the extruded tube on the outer tube 20 can be the same, and the length of each section of the tube ranges from 10mm to 1500mm. Preferably, the length of the extruded tube near the front end of the magnetic conduit is 10mm to 50mm, and the length of the extruded tube near the end of the magnetic conduit is 50mm to 1200mm.

[0067] It should be noted that the thickness and length of each section of the extruded tube may be different, and the outer diameter of the corresponding outer tube 20 and the final magnetic conduit may also vary. Preferably, the thickness of the polymer extruded tube at the front end of the magnetic conduit is 0.005mm-0.02mm smaller than the remaining polymer extruded tube.

[0068] The polymer extruded tubes are spliced ​​together and connected to the inner tube 10 and the middle layer 30 structure by melt coating, and the splicing interfaces of different polymer materials are also formed into an integral structure by melt diffusion.

[0069] Furthermore, for the spliced ​​structures of the sections on the outer tube 20, the spliced ​​joints can be connected by cross-jointed toothed structures to increase the contact area between the two sections and thus enhance the connection strength.

[0070] At the same time, considering that the outer tube 20 of the magnetic catheter is the area in direct contact with the intravascular fluid, in order to improve the running stability of the magnetic catheter in the blood vessel, in some embodiments of the present invention, the outer side of the outer tube 20 of the magnetic catheter at the front end position in the direction of travel is coated with one or more coatings for reducing the surface friction coefficient in a water-based liquid environment. Specifically, it is preferred that the outer side of the outer tube 20 of the front end 10cm-80cm length area of ​​the magnetic catheter is coated with one or more coatings for reducing the surface friction coefficient in a water-based liquid environment, and the coating can be a hydrophilic coating including polyvinyl pyrrolidone, polyacrylic acid, polyacrylamide, polyacrylic acid-acrylamide copolymer, polyethylene glycol; it can also be a hydrophobic coating including polytetrafluoroethylene, perfluoroalkane, perfluoroethylene propylene; both of which can reduce the friction coefficient of the outer tube 20 in the blood vessel. At the same time, it is preferred to reinforce the coating by ultraviolet enhanced curing to ensure the fixing effect of the coating on the outer tube 20.

[0071] Furthermore, the magnetic part 40 is a force-bearing action component at the front end of the magnetic conduit, and it needs to be evenly arranged in the circumferential direction of the magnetic conduit to improve the uniformity of the force. In some embodiments of the present invention, for example Figure 7 As shown, the magnetic part 40 is a metal ring 410 structure and is fixedly arranged on the magnetic conduit to achieve a uniform magnetic field force effect through the circular ring structure. Similarly, the magnetic part 40 can also be metal powder particles 420, which are pre-mixed in the outer tube 20 at a volume fraction of 10%-80%, so as to have a sufficient magnetic effect to drive the front end of the magnetic conduit to achieve a turn. Similarly, as Figure 8 As shown, the magnetic part 40 is a mixed structure of a metal ring 410 and metal powder particles 420 , and the metal ring 410 and the metal powder particles 420 have the same polarity.

[0072] It should be noted that, in the above-mentioned embodiment, the material of the magnetic portion 40 of the metal ring 410 and the metal powder particles 420 is one or more of neodymium iron boron alloy, samarium cobalt alloy, samarium iron nitrogen alloy, aluminum nickel cobalt alloy and ferrite, and the metal powder particles 420 are preferably subjected to magnetic orientation after being combined with the front end of the magnetic conduit to enhance the magnetic strength of the metal powder particles 420.

[0073] Specifically, in some embodiments of the present invention, the magnetic part 40 includes a first magnetic part 40 and a second magnetic part 40, wherein the first magnetic part 40 is a metal ring 410 structure with a thickness of 0.1mm-0.5mm made of neodymium iron boron material, which is placed behind the developing ring at the head end of the catheter at a certain distance. And preferably, 2-6 first magnetic parts 40 are arranged at intervals on each magnetic catheter. The second magnetic part 40 is a metal powder particle 420 made of neodymium iron boron or samarium iron nitrogen material, which is pre-mixed in the polymer extrusion tube with a volume fraction of 60%. After the polymer extrusion tube is melt-coated on the front end of the magnetic catheter to form an outer tube 20, the second magnetic part 40 is also fixed to the front end of the magnetic catheter. Preferably, during the process of melt coating or pre-mixing, the second magnetic part 40 is oriented to improve its magnetic properties.

[0074] In addition, in the magnetic conduit provided in the embodiment of the present invention, similar to the structure of the magnetic part 40, the structure of the developing part 50 can also be attached to the magnetic conduit in the form of a ring or powder, and its structural form and manufacturing process are not repeated here.

[0075] It should be further explained that, in the above embodiments, in order to reduce the difficulty of producing the magnetic catheter, Figure 4 As shown, the magnetic part 40 and the developing part 50 can be combined into a composite ring 60 of an annular metal material. The composite ring 60 is attached to the front end of the magnetic conduit. The width of the composite ring 60 is 0.5mm-4mm, and the wall thickness is 0.1mm-1mm. The composite ring 60 is fixed between the outer tube 20 and the inner tube 10 by melting and coating the outer tube 20. The composite ring 60 can simultaneously provide the developing function of the developing part 50 under X-rays, and the function of the magnetic part 40 being deflected by force under an external magnetic field. And preferably, a plurality of composite rings 60 can be placed continuously on the magnetic conduit at a certain interval length to enhance its developing and magnetic effects. In other embodiments, such as Fig. 9 As shown, the composite ring 60 can also be configured as a matching structure of a large ring and a small ring that are concentrically spaced and sleeved, and each group of composite rings 60 can also be placed in multiples in succession at a certain interval length.

[0076] Furthermore, if Fig.13 and Fig.14As shown, an embodiment of the present invention further provides an interventional device, which includes a magnetic catheter 70 provided in any of the above embodiments, and a magnetic field generating component 80. It should be noted that the magnetic field range of the magnetic field generating component 80 covers the operating area of ​​the magnetic catheter 70, so that the magnetic field generating component 80 can generate an attraction or repulsion effect on the magnetic part 40 on the magnetic catheter 70, so as to pull or push the magnetic part 40 to move, so that the magnetic part 40 drives the front end of the magnetic catheter 70 to deflect, and can achieve bending adjustment in the blood vessel. And because the magnetic catheter 70 has the technical effects provided in any of the above embodiments, the interventional device also has the above technical effects, which will not be repeated here.

[0077] In addition, an embodiment of the present invention further provides a catheter intervention method, which uses the intervention device provided in the above embodiment to implement the intervention of a magnetic catheter in a blood vessel. Specifically, the catheter intervention method includes at least the following steps:

[0078] S01: Pushing the catheter: Pushing the catheter at the end of the magnetic catheter, driving the front end of the magnetic catheter to move in the blood vessel through the support of the middle layer, and displaying the position of the front end of the magnetic catheter in the blood vessel through the developing part.

[0079] S02: Adjust the direction: At the entrance of a blood vessel with a large degree of curvature, a magnetic field parallel to the target blood vessel path is applied by a magnetic field generating component. The magnetic portion of the magnetic catheter is twisted by force, and the front end of the magnetic catheter is driven to deflect in the direction of the target path.

[0080] It should be noted that, for step S02, when it is necessary to pass through a vascular path or other cavity with a large bending angle, the magnetic catheter provided in the embodiment of the present invention does not need to apply a torsional force combined with a push-pull force, or to achieve operations such as bending or preforming of the front end of the magnetic catheter through a guide wire or other structure. Instead, by applying a magnetic field parallel to the target path, the magnetic field will guide the magnetic portion of the magnetic catheter to twist, and the twisted magnetic portion will drive the front end of the magnetic catheter to deflect in the direction of the target path and maintain a state parallel to the target vascular path. At this time, when the end of the magnetic catheter is controlled in vitro, since the front end of the magnetic catheter has been deflected in the target direction under the action of the magnetic field and the magnetic portion, only a thrust is needed, and the entire magnetic catheter can enter the target path under the guidance of the deflected front end.

[0081] S03: Catheter advancement: After the front end of the magnetic catheter completes deflection, the end of the magnetic catheter continues to be pushed outside the body. The magnetic catheter runs along the target blood vessel under the guidance of the magnetic part. When the path in this direction is completed and encounters a subsequent blood vessel entrance with a larger degree of curvature, the direction adjustment steps are repeated to make the magnetic field parallel to the subsequent blood vessel, and drive the magnetic catheter to complete the turn and enter the subsequent blood vessel.

[0082] It should be further explained that if the next path with a large angle bend is encountered, it is only necessary to adjust the direction of the extracorporeal magnetic field again according to the requirements of the subsequent target blood vessel or cavity path, so that the direction of the magnetic field is turned to be parallel to the next target path. At this time, the magnetic part of the magnetic catheter will be deflected again under the action of the transformed magnetic field, and then continue to apply thrust to the tail end of the magnetic catheter outside the body, so that it can cross the curved path again and enter the blood vessel, completing the intervention of the magnetic catheter.

[0083] In addition, in the interventional method provided in an embodiment of the present invention, it is difficult to apply a magnetic field parallel to some more complex vascular structures, so two or more magnetic field generating components can be provided, and the magnetic field generating components cooperate to superimpose the magnetic field effect so that the magnetic portion on the magnetic catheter is subjected to force parallel to the path of the target blood vessel, thereby achieving deflection of the front end of the magnetic catheter.

[0084] In addition, the division of the above-mentioned embodiments is for the convenience of description and shall not constitute any limitation on the specific implementation of the present application. The various embodiments may be combined and referenced with each other without contradiction.

[0085] As used herein, the terms "end" and "front end" refer to the relative orientation, position, and direction of components or actions relative to each other from the perspective of a doctor using the medical device. Although "end" and "front end" are not restrictive, "front end" generally refers to the end that first enters the patient's body, while "end" generally refers to the end that is closer to the doctor during normal operation.

[0086] The magnetic catheter in the present application is particularly used in neurovascular surgery, but can also be used in any interventional, diagnostic and / or therapeutic surgery on the human body or other animals. In addition to neurovascular applications, it also includes blood vessels in other locations, such as the coronary arteries of the heart, the thoracic aorta, the femoral artery, and the vena cava; it can also be used in cavities in the external environment, such as the esophagus, gastrointestinal tract, urethra, etc.

[0087] In the following figures, the overall length of the magnetic catheter is not indicated. The length of the magnetic catheter may vary depending on the type of surgery and the target location, but the magnetic catheter is usually between 50 cm and 200 cm in length.

[0088] According to one embodiment of the present application, the maximum outer diameter of the magnetic catheter used in neurovascular surgery is about 0.05 inches to about 0.1 inches. Other diameter specifications, such as about 0.1 inches to 0.5 inches, are expected to be used for other arterial and venous vessels and external environmental cavities. The diameter of the magnetic catheter can remain relatively constant over most of the catheter length.

[0089] It should be understood that, in order to better describe the present application, some structures in the drawings may not be drawn according to the scale. In addition, some drawings include exaggerated enlargement or out-of-scale parts to show features that are not otherwise obvious.

[0090] In the following, the terms "first", "second", etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features.

[0091] The above description is only a preferred embodiment of the present invention and an explanation of the technical principles used, and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. The scope of the invention involved in the present invention is not limited to the technical solution formed by a specific combination of the above-mentioned technical features, but should also cover other technical solutions formed by any combination of the above-mentioned technical features or their equivalent features without departing from the above-mentioned inventive concept. For example, the above-mentioned features are replaced with the technical features with similar functions disclosed in the present invention (but not limited to) to form a technical solution.

Claims

1. A magnetic catheter, characterized in that: include: The inner tube and the outer tube are nested to form the inner diameter and the outer diameter of the magnetic conduit, and an intermediate layer is embedded and fixed between the inner tube and the outer tube, and the intermediate layer is an elastic layer that can be bent in the circumferential direction and can transmit thrust in the axial direction; The magnetic part and the developing part are both arranged at the front end of the magnetic catheter in the traveling direction. The magnetic part has a single polarity, and the developing part is used to improve the detectability of the magnetic catheter under radiation.

2. The magnetic catheter according to claim 1, characterized in that The intermediate layer includes a first intermediate layer and a second intermediate layer, the first intermediate layer is a metal spring mesh, the second intermediate layer is a metal woven mesh, the first intermediate layer and the second intermediate layer are both cylindrical structures and are concentrically sleeved and fixed, and the first intermediate layer and the second intermediate layer have a constant winding density.

3. The magnetic catheter according to claim 2, characterized in that The second intermediate layer penetrates the magnetic conduit in the axial direction, the first intermediate layer is shorter than the second intermediate layer, and the annular area of ​​the magnetic conduit where the magnetic portion is arranged only includes the second intermediate layer.

4. The magnetic catheter according to claim 1, characterized in that The intermediate layer includes a third intermediate layer and a fourth intermediate layer, the third intermediate layer is a metal spring mesh, the fourth intermediate layer is a metal woven mesh, the third intermediate layer is a stepped cylindrical structure with a variable cross-section along its axial direction, and the winding density in the cylindrical area with a uniform radius is constant; the fourth intermediate layer is also a stepped cylindrical structure with a variable cross-section along its axial direction, and the winding density in the cylindrical area with a uniform radius is constant.

5. The magnetic catheter according to claim 1, characterized in that The middle layer is a single-layer structure, and the material of the middle layer is polymer fiber, metal spring mesh, metal braided mesh, hypotube or combined ring.

6. The magnetic catheter according to claim 1, characterized in that The inner tube is a tubular structure made of one or more of polytetrafluoroethylene, polyolefin and polyethylene through extrusion, dip coating sintering or powder sintering, and the wall thickness of the inner tube is 0.005mm-0.2mm.

7. The magnetic catheter according to claim 1, characterized in that The inner tube is a tubular structure with a uniform inner diameter, or, The inner tube is a variable cross-section structure with an inner diameter that changes evenly and continuously or changes in a gradient, and the end with the smallest inner diameter of the inner tube faces the front end of the magnetic conduit in the traveling direction.

8. The magnetic catheter according to claim 1, wherein: The outer tube is composed of one or more materials of polyamide, polyether block amide, polyurethane and polyolefin.

9. The magnetic catheter according to claim 8, characterized in that The outer layer tube includes at least two sections, a first outer layer tube and a second outer layer tube. The first outer layer tube and the second outer layer tube are spliced ​​and fixed in the axial direction of the outer layer tube and cover the inner layer tube and the middle layer. The hardness of the first outer layer tube is less than that of the second outer layer tube, and the first outer layer tube is arranged closer to the front end of the magnetic conduit in the traveling direction than the second outer layer tube.

10. The magnetic catheter according to claim 9, characterized in that The splicing area of ​​the first outer tube and the second outer tube is a staggered tooth-shaped structure, and the splicing area is fixed into an integral structure by melting and diffusion.

11. The magnetic catheter according to claim 1, wherein: The outer side of the outer tube of the magnetic conduit at the front end position in the traveling direction is coated with one or more coatings for reducing the surface friction coefficient in a water-based liquid environment.

12. The magnetic catheter according to claim 1, wherein: The magnetic part is a metal ring structure and is fixedly arranged on the magnetic conduit, or, The magnetic part is metal powder particles and is pre-mixed in the outer tube at a volume fraction of 10%-80%, or, The magnetic part is a mixed structure of a metal ring and metal powder particles, and the metal ring and the metal powder particles have the same polarity; The material of the magnetic part is one or more of neodymium iron boron alloy, samarium cobalt alloy, samarium iron nitrogen alloy, aluminum nickel cobalt alloy and ferrite.

13. The magnetic catheter according to claim 1, wherein: The developing part is attached to the magnetic guide tube in the form of a ring or powder.

14. An interventional device, characterized in that: The magnetic catheter comprises the magnetic catheter as claimed in any one of claims 1 to 13, and further comprises a magnetic field generating component, wherein the magnetic field generated by the magnetic field generating component covers the operating area of ​​the magnetic catheter and generates an attractive force or a repulsive force on the magnetic part on the magnetic catheter to deflect the magnetic catheter.

15. A catheter intervention method, characterized in that: The intervention device according to claim 14 is used to perform the intervention of the magnetic catheter in a blood vessel, and the catheter intervention method comprises at least the following steps: Pushing the catheter: Pushing the catheter at the end of the magnetic catheter, driving the front end of the magnetic catheter to move in the blood vessel through the support of the middle layer, and displaying the position of the front end of the magnetic catheter in the blood vessel through the developing part; Adjust the direction: At the entrance of a blood vessel with a large curvature, a magnetic field parallel to the target blood vessel path is applied through a magnetic field generating component, and the magnetic part of the magnetic catheter is twisted by force, and the front end of the magnetic catheter is driven to deflect in the direction of the target path; Catheter advancement: After the front end of the magnetic catheter completes deflection, the end of the magnetic catheter continues to be pushed outside the body. The magnetic catheter runs along the target blood vessel under the guidance of the magnetic part. When the path in this direction is completed and encounters the entrance of a subsequent blood vessel with a larger degree of curvature, the direction adjustment steps are repeated to make the magnetic field parallel to the subsequent blood vessel, and drive the magnetic catheter to complete the turn and enter the subsequent blood vessel.

16. The interventional method according to claim 15, characterized in that: In the direction adjustment step, two magnetic field generating components are provided, and the two magnetic field generating components cooperate to apply magnetic force to drive the magnetic portion and the front end of the magnetic catheter to deflect.

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