Medical catheter structure

Abstract

The application discloses a medical catheter structure, which comprises a tube body, the tube body is a hollow structure, a plurality of circumferentially extending cutting zones and a plurality of connecting ribs arranged in the cutting zones are arranged on the tube body along the axial direction of the tube body, the cutting zone can be a strip-shaped slot or a spiral slot cutting zone, and the tube body does not have two sections with the same distribution position of the connecting ribs in the circumferential direction. The application sets the connecting rib in the strip-shaped slot cutting zone to reduce the harmful bending moment effect of the catheter, continuously and gradually changes the same ability of the axial stiffness, the torsional stiffness and the bending stiffness of the catheter in any bending direction, and sets the elimination rib and the elimination moment rib in the spiral cutting slot cutting zone to reduce the spring effect of the pure spiral cutting slot catheter.

Description

Technical Field

[0001] This invention relates to the field of medical device technology, and more particularly to a medical catheter structure. Background Technology

[0002] Minimally invasive interventional surgery is less traumatic, allowing many patients with poor physical conditions to receive treatment, and therefore its application is increasing. Interventional surgery is inseparable from catheters; angiography catheters are needed to observe lesions; and guiding catheters are required during treatment to protect the blood vessels through which the instruments must pass. As the main tool for establishing access in interventional therapy, catheter products have high requirements for pushability, tracking ability, torsion control, flexibility, and kink resistance.

[0003] Different cutting patterns on the catheter body can improve its performance to meet clinical needs. Currently, the most common cutting patterns for hypoem catheters include wavy, serrated, pure spiral, and grooved patterns. While existing cutting structures each have advantages in performance characteristics, design difficulty, and manufacturing efficiency, they all suffer from material deficiencies in the cross-section, resulting in harmful bending moment effects that hinder catheter delivery and distal stability. Furthermore, the pure spiral structure, due to its spring-like structure, also exhibits a spring effect that is not conducive to catheter tracking, passage, and propulsion. Summary of the Invention

[0004] To address the issues in existing technologies where differences in bending stiffness in different directions and the spring effect result in poor catheter delivery, distal stability, throughput, and pushability.

[0005] This application provides a medical catheter structure, including a tube body, which is a hollow structure. The tube body has multiple circumferentially extending cutting areas and multiple connecting ribs disposed in the cutting areas along its axial direction. The tube body does not have two segments in which the connecting ribs are distributed in the same position in the circumferential direction.

[0006] Furthermore, the cutting area is a strip groove, and multiple strip grooves are spaced apart along the axial direction of the tube body.

[0007] Furthermore, when the number n of all the connecting ribs in the same strip groove is odd, the connecting ribs are evenly arranged in the circumferential direction of the pipe body;

[0008] When the number n of all the connecting ribs in the same strip groove is even, the first n / 2 connecting ribs and the last n / 2 connecting ribs are arranged sequentially at an angle of 360 / n, either clockwise or counterclockwise, and the angle between the n / 2th connecting rib and the n / 2+1th connecting rib is 540 / n.

[0009] Furthermore, the included angle between two adjacent connecting ribs in the same strip groove is the rib distribution angle, which is 90° to 135°.

[0010] Furthermore, the helix angle of the connecting rib is 30° to 150°.

[0011] Furthermore, the difference between the rib distribution angle and the rib helix angle is greater than or equal to 20°.

[0012] Furthermore, the cutting area is a spiral cutting groove provided on the pipe body, and the spiral cutting groove is provided with a plurality of connecting ribs, the connecting ribs including spring-reducing ribs and torque-reducing ribs, the spring-reducing ribs and the torque-reducing ribs being arranged sequentially and cyclically along the axial direction of the pipe body.

[0013] Furthermore, the helical angle between two adjacent shock absorbers is greater than or equal to 430°.

[0014] Furthermore, the tube body is evenly divided into four regions in the circumferential direction, and two adjacent elastic ribs and moment ribs are respectively set in the two adjacent regions, and all the elastic ribs and moment ribs are evenly distributed in the four regions of the tube body.

[0015] Furthermore, the offset angle between adjacent elastic ribs and torque ribs is the elastic torque offset angle, which is 80° to 100°.

[0016] This application has the following beneficial effects:

[0017] This application reduces the harmful bending moment effect of the conduit by setting connecting ribs in the strip groove cutting area, so that the axial stiffness, torsional stiffness and bending stiffness in any bending direction of the conduit are continuously and gradually changed; by setting elasticity-reducing ribs and moment-reducing ribs in the spiral cutting groove cutting area, the spring effect of the pure spiral cutting groove conduit is reduced, and the bending stiffness of the conduit changes consistently in any direction along the axial direction. Attached Figure Description

[0018] To more clearly illustrate the technical solution of the present invention, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a cylindrical surface development view of a guide tube with two connecting ribs in the same strip groove according to Embodiment 1 of the present invention;

[0020] Figure 2 This is a cross-sectional view of a conduit with two connecting ribs in the same strip groove according to Embodiment 1 of the present invention;

[0021] Figure 3 This is a cylindrical development view of a guide tube with three connecting ribs in the same strip groove according to Embodiment 1 of the present invention;

[0022] Figure 4 This is a cross-sectional view of a conduit with three connecting ribs in the same strip groove according to Embodiment 1 of the present invention;

[0023] Figure 5 This is a cylindrical surface development view of the medical catheter structure of Embodiment 2 of the present invention;

[0024] Figure 6 This is a cross-sectional stress distribution diagram when a non-cut hysteresis tube and a purely helically cut conduit undergo bending deformation.

[0025] In the figure, the corresponding reference numerals are: tube body 1, spiral cutting groove 2, strip groove 3, connecting rib 4, elastic rib 41, and moment rib 42. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "top," "bottom," and "side," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0028] Furthermore, in this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0029] Medical catheters can be used in various interventional devices, such as microcatheters, microguidewires, balloon catheters, and thrombectomy stents / coil delivery guidewires. Different cutting patterns are used in different devices to meet their respective performance requirements. Currently, the most common tube body cutting patterns are pure helical cuts and grooved cuts. These two cutting structures each have advantages in performance characteristics, design difficulty, and manufacturing efficiency. However, because of the material loss in the cross-section, both have harmful bending moment effects that are detrimental to catheter delivery and distal stability. Furthermore, the pure helical structure, because its structure is similar to a spring, also has a spring effect that is not conducive to catheter tracking, passage, and propulsion.

[0030] The spring effect refers to the phenomenon where, when the cutting structure of a conduit resembles a spring, such as in a pure helical cut, under the same stiffness design, because the cutting groove exists as a complete helix throughout the conduit, the conduit undergoing a pure helical cut will store more strain energy when faced with deformations such as tension, compression, bending, and torsion. This can lead to problems such as delayed or even abrupt distal actions when operating the conduit proximally.

[0031] Harmful bending moment effects refer to the additional bending moments generated in a specific cross-section, typically a tubular cross-section with material defects or poor symmetry, when subjected to tensile, compressive, or bending deformation, leading to unintended deflection of the catheter. The essence of this bending moment effect lies in the uneven distribution of normal stress on the poorly symmetrical cross-section, resulting in uneven bending moments in a certain direction. Poor symmetry means that the cross-section of the tubular body cannot achieve axisymmetry about any one axis. In medical applications, catheters face various bending environments, so it is necessary to reduce or eliminate harmful bending moment effects to improve the stability of catheter delivery.

[0032] The harmful bending moment effect is further elucidated through stress analysis of uncut, purely helically cut, and grooved-patterned hypotubes during bending deformation. Figure 6 As shown in (a), when bending deformation occurs when a bending moment M is applied to both ends of the uncut submersible tube, because the cross-section of the uncut submersible tube is axisymmetric about any axis passing through the center of the circle, the resultant bending moment of the normal stress on the cross-section about Y is 0, that is, no additional harmful bending moment effect is generated. Figure 6 As shown in (b), when a bending moment M is applied to both ends of the purely helical cut conduit, causing bending deformation, such as a smiley face bend with X as the neutral layer, the stress distribution of its cross-section is the same as above. However, due to the pure helical cutting, its cross-section has a notch feature, and the stress disappears here. Therefore, in the Y-axis direction perpendicular to the current neutral axis X, the resultant bending moment of the normal stress on the cross-section about the Y-axis is no longer 0, which will produce an additional harmful bending moment effect. Its effect is to cause the purely helical cut conduit to bend along the Y-axis, that is, to manifest as uncontrolled, random oscillation of the distal end of the conduit.

[0033] The cross-sectional shape of grooved subwoofer tubes also exhibits material deficiencies, the areas of which are related to the number and width of the ribs in the grooves. However, because it is impossible to achieve axial symmetry of the cross-section on any axis passing through the center of the circle, it will inevitably produce a harmful bending moment effect similar to that of purely helical-cut subwoofer tubes.

[0034] Example 1

[0035] To address the harmful bending moment effect and spring effect problems existing in current medical catheters, Embodiment 1 of this application provides a medical catheter structure, such as... Figure 1-4 As shown, it includes a tube body 1, which is a hollow structure. The tube body 1 has multiple circumferentially extending cutting areas and multiple connecting ribs 4 arranged in the cutting areas along its axial direction. The tube body 1 does not have two sections with the same circumferentially distributed connecting ribs 4.

[0036] Specifically, the cutting area is a strip groove 3, and multiple strip grooves 3 are spaced apart along the axial direction of the pipe body 1. Each strip groove 3 is provided with at least two connecting ribs 4, and all connecting ribs 4 are spirally arranged along the axial direction of the pipe body 1.

[0037] Specifically, in some embodiments, to reduce the difference in bending stiffness of the same cross section in different directions, the distribution of connecting ribs 4 within the same strip groove should ensure that the worst bending direction of each rib, i.e., the direction with the largest moment of inertia, is evenly distributed around the circumference. When the number n of all connecting ribs 4 in the same strip groove 3 is odd, the connecting ribs 4 are evenly arranged in the circumferential direction of the pipe body 1, i.e., all connecting ribs are arranged clockwise or counterclockwise at an angle of 360 / n. When the number n of all connecting ribs 4 in the same strip groove 3 is even, the first n / 2 connecting ribs 4 and the last n / 2 connecting ribs 4 are arranged clockwise or counterclockwise at an angle of 360 / n, and the angle between the n / 2th connecting rib 4 and the n / 2+1th connecting rib 4 is 540 / n. The number of connecting ribs 4 can be determined according to the required bending stiffness and torsional stiffness of the conduit. Fewer connecting ribs can improve the flexibility of the conduit, while more connecting ribs can increase the rigidity of the conduit. In some implementations, the number of connecting ribs can generally be set to 2 to 4.

[0038] In other embodiments, when the aim is to reduce the harmful bending moment effect of the defective section, the distribution of the connecting ribs 4 within the same strip groove should minimize the additional bending moment effect of the section in any direction. Specifically, the pipe body 1 is uniformly divided into four regions in the circumferential direction, and adjacent connecting ribs 4 in the same strip groove 3 are placed in adjacent regions. All connecting ribs 4 are uniformly distributed in the four regions of the pipe body 1. That is, if a rectangular coordinate system in any direction is established on the cross-section of the pipe body 1, then all connecting ribs should fall in adjacent quadrants with the highest probability, and the number of connecting ribs in each quadrant should be minimized. Optionally, the distribution angle between connecting ribs with opposite or the same direction of stress on the cross-section of the pipe body should be between 90° and 180° with the highest probability. Specifically, the included angle between two adjacent connecting ribs 4 in the same strip groove 3 is the rib distribution angle α, which is between 90° and 135°. Preferably, when the number of connecting ribs 4, n = 2, the rib distribution angle α is 90°; when n = 3, the rib distribution angle α > 90°, preferably 120°; when n = 4, the rib distribution angle α is 90°. For example, ... Figure 1 and 2 The diagram shows the possible distribution of connecting ribs 4 on the cross-section of the pipe at the groove when there are two connecting ribs 4 within the same groove; for example... Figure 3 and 4 The figure shows the possible distribution of the connecting ribs 4 on the cross-section of the pipe at the groove when the number of connecting ribs 4 in the same groove is 3.

[0039] This embodiment combines two principles: reducing the difference in bending stiffness of the same cross section in different directions and reducing the harmful bending moment effect of defective cross sections. It can determine the distribution angle between adjacent connecting bars under different numbers of connecting bars.

[0040] Specifically, in some embodiments, the helix angle β of the connecting rib 4 is 30° to 150°. Specifically, in some embodiments, the difference between the rib distribution angle and the rib helix angle is greater than or equal to 20°. In this embodiment, all connecting ribs 4 are spirally arranged along the axial direction of the pipe body 1, and the offset angle between connecting ribs in adjacent two grooves is the rib helix angle β. The purpose of setting the rib helix angle β is to evenly distribute the asymmetric defects on each groove section along the axial direction on the circumference. On the one hand, this ensures that the guide tube can exhibit the same stiffness characteristics in any direction; on the other hand, it can offset the harmful bending moment effect that is difficult to completely eliminate in each section through appropriate rib helix angle design.

[0041] The design principles of the rib helix angle β in this embodiment are as follows: (1) To avoid the slow change of the most difficult bending direction (the corresponding section with the largest moment of inertia) along the axial direction of the guide tube, resulting in differences in bending stiffness in different directions, the rib helix angle β is 30° to 150°. (2) Based on the number of slots 3 on the tube body, to ensure that there are no two sections of the tube body 1 with the same distribution position of the connecting ribs 4 in the circumferential direction, that is, all connecting ribs 4 are evenly distributed in the circumferential direction, the accurate value of the rib helix angle β is calculated. (3) To ensure that the most difficult bending direction changes rapidly in the axial direction, that is, the same or approximately the most difficult bending direction is not concentrated in the axial direction. Based on the principle that all connecting ribs 4 are evenly distributed in the circumferential direction, the rib helix angle β should be 90° ± 20°. (4) The difference between the size of the rib helix angle β and the rib distribution angle α is greater than or equal to 20°, so that the same or approximately the most difficult bending direction is not concentrated in the axial direction. (5) In order to avoid the connecting ribs 4 on the groove row from being distributed circumferentially in the pipe body, causing the guide tube to have an uneven dominant bending direction, the rib helix angle β and similar angles cannot be divided by 360° and its integer multiples.

[0042] In this embodiment, the length L1 of the strip groove cutting area on the tube body 1, or the number of groove rows in the strip groove cutting area, can be determined according to the design requirements of the conduit.

[0043] This embodiment reduces the harmful bending moment effect of the conduit by setting connecting ribs in the strip groove cutting area, so that the axial stiffness, torsional stiffness and bending stiffness in any bending direction of the conduit are continuously and gradually varied, that is, the cross-sectional characteristics of the conduit are continuously and gradually varied in any direction.

[0044] Example 2

[0045] Embodiment 2 of this application provides a medical catheter structure, such as Figure 5 As shown, it includes a tube body 1, which is a hollow structure. The tube body 1 has multiple circumferentially extending cutting areas and multiple connecting ribs 4 arranged in the cutting areas along its axial direction. The tube body 1 does not have two sections with the same circumferentially distributed connecting ribs 4.

[0046] Specifically, the cutting area is a spiral cutting groove 2 set on the pipe body 1. Multiple connecting ribs 4 are provided within the spiral cutting groove 2. The connecting ribs 4 include spring-absorbing ribs 41 and moment-absorbing ribs 42, which are sequentially and cyclically arranged along the axial direction of the pipe body 1. In this embodiment, the spring-absorbing ribs 41 and moment-absorbing ribs 42 are provided within the spiral cutting groove to reduce its spring effect and harmful bending moment effect.

[0047] Specifically, the spring-reducing helical angle γ between two adjacent spring-reducing ribs 41 is greater than or equal to 430°. The design principle of the spring-reducing helical angle γ in this embodiment is as follows: (1) According to the formula of moment of inertia of section, in order to satisfy the requirement that the bending stiffness of the duct exhibits approximately bending characteristics in different bending directions, the spring-reducing helical angle γ between two adjacent spring-reducing ribs 41 is approximately 90° + 360° * n, where n is a positive integer. Optionally, the spring-reducing helical angle γ is greater than or equal to 430°. In order to better eliminate the spring effect without causing too much impact on the stiffness of the duct, the spring-reducing helical angle γ between two adjacent spring-reducing ribs 41 is preferably 450°, which is the reference helical angle. (2) To avoid the bending direction of the conduit caused by mass concentration, the connecting ribs 4 should be uniformly distributed non-periodically in the circumferential direction of the tube body 1. That is, there are no two sections of the tube body 1 with the same distribution position of the connecting ribs 4 in the circumferential direction. Therefore, based on the reference helical angle, the number of connecting ribs 4 can be initially determined according to the number of helical cutting grooves 2 on the tube body 1. Based on the principle that all connecting ribs 4 should be uniformly distributed non-periodically in the circumferential direction of the tube body 1, the specific value of the spring-reducing helical angle γ can be accurately determined. Furthermore, the final helical angle is determined with the spring-reducing helical angle γ as the center and within a range of ±10°. In this embodiment, the difference between the final helical angle and the spring-reducing helical angle γ is within a certain range to avoid the calculated number of connecting ribs 4 differing too much from the initial setting. (3) To avoid the periodic cyclic distribution of connecting ribs 4 in the circumferential direction of the tube body caused by processing errors, resulting in uneven bending direction and affecting the performance of the conduit, the spring-reducing helical angle γ and its similar angles are not divisible by 360 degrees and its integer multiples.

[0048] The harmful bending moment effect refers to the asymmetry caused by the lack of cross-sectional material, which leads to an imbalance of bending moments in certain directions due to cross-sectional stress. The spring-reducing helical angle introduced to reduce the spring effect exacerbates the harmful bending moment effect because it disrupts the self-cancellation of harmful bending moments within the cycle of a pure helical structure. Therefore, by introducing a spring-reducing helical angle, the harmful bending moment effect generated by simply setting the spring-reducing helical angle can be offset. The design principle of the spring-reducing helical angle δ in this embodiment is the same as that of the spring-reducing helical angle.

[0049] Specifically, the offset angle between adjacent spring-reducing ribs 41 and moment-reducing ribs 42 is the spring-moment offset angle θ, which is 80° to 100°. The setting of the spring-moment offset angle θ can eliminate the harmful bending moment effect generated by the setting of connecting ribs. The design principle of the spring-moment offset angle θ is: (1) The theoretical principle is that the distribution of spring-reducing ribs and moment-reducing ribs in the same spiral cycle should make the cross section generate the minimum additional bending moment effect in any direction, that is, the bending moment effects of spring-reducing ribs and moment-reducing ribs cancel each other out. (2) The pipe body 1 is evenly divided into four regions in the circumferential direction. Two adjacent spring-reducing ribs 41 and moment-reducing ribs 42 are respectively set in two adjacent regions, and all spring-reducing ribs 41 and moment-reducing ribs 42 are evenly distributed in the four regions of the pipe body 1. That is, a rectangular coordinate system in any direction is established on the cross section of the pipe body, then the two connecting ribs 4 fall in adjacent quadrants with the highest probability and the number of ribs in each quadrant is minimized. (3) In some embodiments, preferably, the spring-moment offset angle θ is 90°.

[0050] In this embodiment, the length L2 of the spiral cut section of the tube body 1 or the number of spirals can be determined according to the design requirements of the conduit and is not mandatory.

[0051] This embodiment reduces the spring effect of the pure spiral cut groove guide tube by setting up spring-reducing ribs and torque-reducing ribs in the spiral cut groove cutting area, and makes the bending stiffness of the guide tube change consistently in any direction along the axial direction.

[0052] The above-disclosed embodiments are merely preferred exemplary embodiments of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any equivalent variations made in accordance with the claims of the present invention are still within the scope of the present invention.

Claims

1. A medical catheter structure, characterized in that, Includes a tube body (1), the tube body (1) is a hollow structure, the tube body (1) is provided with a plurality of circumferentially extending cutting areas and a plurality of connecting ribs (4) arranged in the cutting areas along its axial direction, the tube body (1) does not have two sections in the circumferential direction where the connecting ribs (4) are distributed in the same position; The cutting area is a strip groove (3), and multiple strip grooves (3) are spaced apart along the axial direction of the tube body (1); The number of all the connecting ribs (4) in the same strip groove (3) is n: When n=2, the included angle between the two connecting ribs (4) is 90°; When n is an even number greater than 2, the first n / 2 connecting ribs (4) and the last n / 2 connecting ribs (4) are arranged clockwise or counterclockwise at an angle of 360 / n, and the angle between the n / 2th connecting rib (4) and the n / 2+1th connecting rib (4) is 540 / n.

2. The medical catheter structure according to claim 1, characterized in that, The helix angle of the connecting bar (4) is 30° to 150°.

3. A medical catheter structure according to claim 2, characterized in that, The included angle between two adjacent connecting ribs (4) in the same strip groove (3) is the rib distribution angle, and the difference between the rib distribution angle and the rib helix angle is greater than or equal to 20°.

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