Bile duct stent

Abstract

The bile duct stent comprises a stent main body and a backflow prevention device, wherein the backflow prevention device comprises a conical spiral diaphragm, a conical spiral elastic metal wire and a plurality of limiting pieces; the conical spiral diaphragm is provided with more than four spiral layers, the elastic metal wire is provided with three spiral layers, and the elastic metal wire is embedded in the three spiral layers at the top of the conical spiral diaphragm and provides axial elastic support for the three spiral layers at the top of the conical spiral diaphragm; the limiting piece is arranged on the bottommost spiral layer of the conical spiral diaphragm and fixed to the support body, and when the conical spiral diaphragm is compressed, the outer layer of the last spiral layer abuts against the limiting piece, so that reverse movement of the conical spiral diaphragm is limited. Therefore, the situation that the conical spiral diaphragm is pressed to move reversely due to the fact that the pressure of a backflow object is too large can be prevented, and the backflow prevention effect is improved.

Description

Technical Field

[0001] The present application relates to the field of bile duct stents, and in particular to a bile duct stent capable of preventing backflow. Background Art

[0002] As a precise tubular medical device, bile duct stents are widely used in the treatment of the bile duct system. Its manufacturing materials are mainly divided into metal materials (represented by nickel-titanium alloy) and biodegradable polymer materials. From a structural point of view, the bile duct stent consists of a tubular support body and an anchoring structure. The diameter of the support body is generally between 6 and 10 mm, and the length is flexibly adjusted within the range of 4 to 12 cm according to the specific implantation site. In clinical operations, doctors will accurately implant the stent into the intrahepatic and extrahepatic bile ducts, including key locations such as the common hepatic duct, common bile duct, and left and right hepatic duct branches, through percutaneous puncture or endoscopic retrograde surgery.

[0003] The core function of a biliary stent is mechanical support. By expanding the bile duct, it effectively maintains bile duct patency, thereby resolving the problem of bile stasis caused by bile duct stenosis, tumor compression, or cholelithiasis. However, biliary stents still face numerous technical challenges. For one thing, the radial support force of existing stents is significantly insufficient, especially for biodegradable stents, which are prone to plastic deformation in the presence of fibrosis or tumor progression in the bile duct wall. Clinical research data show that some patients experience radial contraction of the stent after implantation, leading to secondary bile duct stricture. Furthermore, traditional open stent structures have design flaws that make it difficult to effectively prevent the reflux of intestinal contents. When intraduodenal pressure increases, such as when gastrointestinal motility is excessively vigorous, some patients experience retrograde bacterial infection, leading to complications such as cholangitis. These technical bottlenecks significantly limit the long-term therapeutic effectiveness of biliary stents and significantly increase the risk of patients requiring secondary medical interventions.

[0004] In the Chinese patent with publication number CN112220594B and the name “A Conical Spiral Valve Anti-Reflux Biliary Stent”, it is proposed to prevent the reflux of intestinal contents by designing a conical spiral valve structure. However, in actual applications, it was found that there is a mechanical contradiction between the morphology of this conical spiral valve and the radial contraction characteristics of the stent itself: when the stent is subjected to external pressure (such as tumor development causing the diameter to narrow), the spiral valve will have asymmetric wrinkles, which will cause local blockage of the bile duct. In addition, the conical spiral valve relies on the contact of the edges of each spiral layer to achieve one-way flow obstruction, but once the reflux pressure is too large, the valve will move in the opposite direction after being compressed to the limit, and will not be able to effectively block the reflux. Therefore, it is very necessary to optimize the existing bile duct stents to enhance the anti-reflux ability and avoid the problem of content obstruction. Summary of the Invention

[0005] In view of the above problems, the present application provides a bile duct stent for solving the technical problems in the prior art that the spiral valve is prone to reverse movement when under pressure and has poor anti-backflow effect.

[0006] To achieve the above objectives, the present application provides a bile duct stent, comprising:

[0007] The stent body is formed by braiding memory alloy, has a straight cylindrical shape, and can be elastically supported in the radial direction;

[0008] An anti-backflow device is fixedly arranged at the front section of the interior of the stent body and is used to block intestinal and bile reflux; the anti-backflow device includes: a conical spiral diaphragm, a conical spiral elastic metal wire and a plurality of limit plates;

[0009] The conical spiral diaphragm has more than four spiral layers, and the elastic metal wire has three spiral layers and is embedded in the three spiral layers at the top of the conical spiral diaphragm to provide axial elastic support for the three spiral layers at the top;

[0010] A plurality of the limiting pieces are bonded to the back of the bottom spiral layer of the conical spiral diaphragm at intervals, and the outer sides of the limiting pieces are fixed to the bracket body, and the inner sides of the limiting pieces extend radially;

[0011] When the conical spiral diaphragm is compressed along the axial direction of the stent body, the spiral layers of the conical spiral diaphragm are closed, and the outer side of the second bottom spiral layer is supported on the inner side of the limiting piece to prevent the bottom of the conical spiral diaphragm from reverse deformation.

[0012] Furthermore, two or more protrusions are provided on the inner side of the second bottom spiral layer, and the circumferential positions of the protrusions are the same as those of the limiting pieces; the protrusions are used to support the upper spiral layer when the conical spiral diaphragm is compressed.

[0013] Furthermore, three of the limiting pieces are arranged at intervals on the bottom spiral layer.

[0014] Furthermore, the thickness of the two spiral layers at the bottom of the conical spiral diaphragm is smaller than the thickness of the spiral layer at the top of the conical spiral diaphragm.

[0015] Furthermore, the elastic metal wire is made of beryllium copper alloy or nickel titanium alloy.

[0016] Furthermore, the front end of the bracket body is a trumpet mouth that expands toward the periphery.

[0017] Furthermore, the radial width of each spiral layer of the conical spiral diaphragm gradually decreases from the bottom layer to the top layer.

[0018] Furthermore, the limiting piece is made of polytetrafluoroethylene or polyetheretherketone.

[0019] Furthermore, two or more metal markers are respectively provided at both ends of the stent body, and the metal markers are used to assist image positioning.

[0020] Furthermore, the length of the stent body is 6-10 mm.

[0021] Different from the prior art, the bile duct stent of the above technical solution includes a stent body and an anti-backflow device, wherein the backflow device includes a conical spiral diaphragm, a conical spiral elastic wire and a plurality of limit plates; wherein the conical spiral diaphragm has more than four spiral layers, the elastic wire has three spiral layers, and is buried in the three spiral layers at the top of the conical spiral diaphragm, providing axial elastic support for the three spiral layers at the top, so that it can withstand greater axial pressure. And the plurality of limit plates are bonded to the back of the bottom spiral layer of the conical spiral diaphragm at intervals, and the outer side of the limit plate is fixed to the stent body, and the inner side of the limit plate extends radially; when the conical spiral diaphragm is compressed along the axial direction of the stent body, the spiral layers of the conical spiral diaphragm are closed, and the outer side of the second bottom spiral layer is supported on the inner side of the limit plate to prevent the bottom of the conical spiral diaphragm from reverse deformation.

[0022] The above-mentioned records related to the content of the invention are only an overview of the technical solution of this application. In order to enable ordinary technicians in this field to understand the technical solution of this application more clearly, and then implement it according to the text of the specification and the contents recorded in the drawings, and to make the above-mentioned purposes and other purposes, features and advantages of this application easier to understand, the following is an explanation in combination with the specific implementation methods and drawings of this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are only used to illustrate the principles, implementation methods, applications, characteristics and effects of the specific embodiments of the present invention and other related contents, and are not to be considered as limiting the present application.

[0024] In the drawings of the specification:

[0025] Figure 1 Schematic diagram of the structure of the bile duct stent described in the specific embodiment;

[0026] Figure 2 It is a structural schematic diagram of the anti-backflow device described in a specific embodiment;

[0027] Figure 3 for Figure 2 A partial enlarged view of part A;

[0028] The reference numerals in the above drawings are described as follows:

[0029] 1. Bracket body; 11. Metal mesh;

[0030] 2. Anti-backflow device; 21. Conical spiral diaphragm; 22. Elastic metal wire; 23. Limiting piece;

[0031] 211, protrusion; 231, groove; DETAILED DESCRIPTION

[0032] In order to explain in detail the possible application scenarios, technical principles, specific solutions that can be implemented, and the purpose and effects of this application, the following is a detailed description of the specific embodiments listed in conjunction with the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of this application and are therefore only examples and are not intended to limit the scope of protection of this application.

[0033] References to "embodiments" herein mean that the specific features, structures, or characteristics described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the word "embodiment" in various places in the specification does not necessarily refer to the same embodiment, nor does it particularly limit its independence or relevance to other embodiments. In principle, in this application, as long as there are no technical contradictions or conflicts, the various technical features mentioned in the embodiments can be combined in any manner to form a corresponding implementable technical solution.

[0034] Unless otherwise defined, the technical terms used herein have the same meanings as those generally understood by those skilled in the art to which this application belongs; the use of relevant terms herein is only for describing specific embodiments and is not intended to limit this application.

[0035] In the description of this application, the term "and / or" is used to describe a logical relationship between objects, indicating that three relationships can exist. For example, A and / or B means: A exists, B exists, and both A and B exist. In addition, the character " / " in this document generally indicates that the objects before and after are in a logical "or" relationship.

[0036] In this application, terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual quantity, priority or sequence relationship between these entities or operations.

[0037] Without further limitations, in this application, the words "include", "comprise", "have" or other similar open-ended expressions used in sentences are intended to cover non-exclusive inclusion. These expressions do not exclude the presence of additional elements in the process, method or product that includes the elements, so that the process, method or product that includes a series of elements may include not only those defined elements, but also other elements that are not explicitly listed, or also include elements inherent to such process, method or product.

[0038] Consistent with the understanding in the Examination Guidelines, in this application, expressions such as "greater than," "less than," and "exceed" are understood to exclude the number itself; expressions such as "above," "below," and "within" are understood to include the number itself. Furthermore, in the description of the embodiments of this application, "multiple" means more than two (including two), and similar expressions related to "multiple" are also understood in this manner, such as "multiple groups," "multiple times," etc., unless otherwise specifically defined.

[0039] In the description of the embodiments of the present application, the space-related expressions used, such as "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "vertical", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or position relationship based on the orientation or position relationship shown in the specific embodiments or drawings, and are only for the convenience of describing the specific embodiments of the present application or facilitating the reader's understanding, and do not indicate or imply that the device or component referred to must have a specific position, a specific orientation, or be constructed or operated in a specific orientation. Therefore, it should not be understood as a limitation on the embodiments of the present application.

[0040] Unless otherwise expressly specified or limited, in the description of the embodiments of the present application, the terms "installed", "connected", "connected", "fixed", "set", etc. used should be understood in a broad sense. For example, the "connection" can be a fixed connection, a detachable connection, or an integrated setting; it can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal connection of two elements or the interaction relationship between two elements. For those skilled in the art of the present application, the specific meanings of the above terms in the embodiments of the present application can be understood according to the specific circumstances.

[0041] See also Figures 1 to 3, this embodiment provides a bile duct stent. The bile duct stent includes: a stent body 1 and an anti-backflow device 2. Among them, the stent body 1 is woven from a memory alloy, has a shape of a right cylinder, and can be elastically supported radially. The stent body 1 is woven from an alloy to form a radially elastic metal mesh 11. The alloy has strong elasticity. Therefore, when the stent body 1 is placed in the stricture section of the bile duct, the stent body 1 can be stretched outward, thereby expanding the stricture section of the bile duct, thereby solving or alleviating the problem of bile stasis caused by bile duct stricture, tumor compression or cholelithiasis. In this embodiment, the alloy used for the stent body 1 can be a nickel-titanium alloy. The diameter of the stent body 1 is usually 6-10 mm, and the length is between 4-12 cm depending on the implantation site. In order to fix the stent body 1 and prevent the position of the stent body 1 from shifting after being placed in the bile duct, the front and rear ends of the stent body 1 are both trumpet-shaped and expand outward, that is, the diameters of the front and rear ends of the stent body 1 are larger than the middle section, and the force of the front and rear ends being stretched outward is also greater than that of the middle section, so that the front and rear ends can be more stably fixed in the bile duct. Two or more metal markers are respectively provided at both ends of the stent body 1, and the metal markers are used to assist in image positioning. The metal markers can be precious metals such as gold and platinum with good radiopaqueness, so they can be clearly visualized in imaging examinations such as X-rays and CT. In this embodiment, by providing metal markers at both ends of the stent body, the doctor can intuitively judge the position, shape and whether the stent has shifted, and ensure that the stent is accurately placed in the target bile duct area, which is particularly suitable for complex bile duct structures or postoperative review scenarios.

[0042] The backflow prevention device 2 is fixedly mounted on the front section of the interior of the stent body 1 and is used to block intestinal and bile reflux. The backflow prevention device 2 comprises a conical spiral diaphragm 21, a conical spiral elastic wire 22, and a plurality of limiting plates 23. The conical spiral diaphragm 21 has more than four spiral layers, and the elastic wire 22 has three spiral layers and is embedded in the three spiral layers at the top of the conical spiral diaphragm 21 to provide axial elastic support for the three spiral layers at the top. The plurality of limiting plates are bonded to the back of the bottommost spiral layer of the conical spiral diaphragm 21 at intervals, and the outer sides of the limiting plates are fixed to the stent body 1, while the inner sides of the limiting plates extend radially. From the bottom to the top, the radial width of each spiral layer of the conical spiral diaphragm 21 gradually decreases. When the conical spiral diaphragm 21 is compressed along the axial direction of the stent body 1, the spiral layers of the conical spiral diaphragm 21 are closed, and the outer side of the second-bottom spiral layer is supported on the inner side of the limit plate to prevent the bottom of the conical spiral diaphragm 21 from reverse deformation. The elastic metal wire 22 is made of beryllium copper alloy or nickel-titanium alloy. Beryllium copper alloy or nickel-titanium alloy has strong elasticity, thereby providing a strong elastic support force for the top of the conical spiral diaphragm 21. The elastic metal wire 22 is a conical spiral, such as Figure 2As shown, its characteristic is that the diameter of the spiral gradually decreases from the bottom to the top, so that the whole structure is conical. The structure of the conical spiral diaphragm 21 is similar, and the diameter gradually decreases from the bottom to the top.

[0043] In this embodiment, the bottom spiral layer of the conical spiral diaphragm 21 is provided with three limiting plates 23 at equal intervals; that is, each limiting plate 23 is spaced 120 degrees apart in the circumferential direction, so that the conical spiral diaphragm 21 can be effectively supported. In other embodiments, two limiting plates 23, or more than four limiting plates 23, may be spaced apart on each spiral layer. The limiting plates 23 are in the shape of hard sheets, and can be made of polytetrafluoroethylene or polyetheretherketone. The radial width of the limiting plates 23 is equivalent to the radial width of the conical spiral diaphragm 21 at its location, or slightly smaller than the radial width of the conical spiral diaphragm 21, but the inner side of the limiting plates 23 protrudes inward relative to the conical spiral diaphragm 21, and the circumferential width of the limiting plates 23 can be 2-3 mm. The limiting piece 23 can increase the supporting area of ​​the elastic metal wire 22 and the conical spiral diaphragm 21, preventing the conical spiral diaphragm 21 from unexpectedly deforming when it is under pressure, and the limiting piece 23 can prevent the conical spiral diaphragm 21 from deforming in the opposite direction when it is under pressure, that is, after the conical spiral diaphragm 21 is compressed to a plane, its top continues to move in the opposite direction ( Figure 1 Move in the opposite direction of the arrow L).

[0044] like Figure 3 As shown, in this embodiment, the upper surface of the inner side of the limiting plate is thinned to form a sunken groove 231, which abuts against the outer side of the previous spiral layer.

[0045] In this embodiment, the top spiral layers of the conical spiral diaphragm 21 are reinforced with elastic wires 22 to increase elasticity, so that they can withstand great pressure; the limiting pieces 23 on the bottom spiral layer of the conical spiral diaphragm 21 are fixed to the stent body 1, and can be specifically tied to the stent body 1 by medical sutures. Therefore, when the conical spiral diaphragm 21 is compressed (i.e. Figure 1 The corresponding limiting pieces 23 on each spiral layer will approach each other, and eventually the inner side of the limiting piece 23 will be against the outer side of the upper spiral layer, so that the pressure is finally transmitted to the limiting piece 23 of the bottom spiral layer. The limiting piece 23 of the bottom spiral layer is fixed on the bracket body 1, so it can prevent the position of the limiting piece 23 on the upper spiral layer from exceeding the position of the limiting pieces 23 of the bottom spiral layer, thereby preventing the conical spiral diaphragm 21 from exceeding the compression limit and reversing (i.e. Figure 1 Reverse conduction caused by movement in the opposite direction (in the opposite direction indicated by the arrow L).

[0046] like Figure 2As shown, two or more protrusions 211 are provided on the inner side of the second-bottom spiral layer of the conical spiral diaphragm 21. The protrusions 211 are located at the same circumferential position as the limiting piece. The protrusions 211 are used to support the upper spiral layer when the conical spiral diaphragm 21 is compressed. The protrusions 211 can be formed by protruding inward from the main body of the conical spiral diaphragm 21. That is, the protrusions 211 are integral with the conical spiral diaphragm 21 and are part of the conical spiral diaphragm 21, but only protrude inward relative to the main body.

[0047] In this embodiment, since a limit plate 23 is provided at the bottom layer of the conical spiral diaphragm 21, it can reliably prevent its reverse movement. Therefore, in order to reduce the volume of the conical spiral diaphragm 21, the thickness of the bottom spiral layer of the conical spiral diaphragm 21 is less than the thickness of the spiral layer at the top of the conical spiral diaphragm 21.

[0048] Finally, it should be noted that although the above embodiments have been described in the specification and drawings of this application, this does not limit the scope of patent protection of this application. All technical solutions generated by replacing or modifying equivalent structures or equivalent processes based on the essential concepts of this application using the contents recorded in the specification and drawings of this application, as well as directly or indirectly implementing the technical solutions of the above embodiments in other related technical fields, are included in the scope of patent protection of this application.

Claims

1. A bile duct stent, characterized in that: include: The stent body is formed by braiding memory alloy, has a straight cylindrical shape, and can be elastically supported in the radial direction; An anti-backflow device is fixedly arranged at the front section of the interior of the stent body and is used to block intestinal and bile reflux; the anti-backflow device includes: a conical spiral diaphragm, a conical spiral elastic metal wire and a plurality of limit plates; The conical spiral diaphragm has more than four spiral layers, and the elastic metal wire has three spiral layers and is embedded in the three spiral layers at the top of the conical spiral diaphragm to provide axial elastic support for the three spiral layers at the top; A plurality of the limiting pieces are bonded to the back of the bottom spiral layer of the conical spiral diaphragm at intervals, and the outer sides of the limiting pieces are fixed to the bracket body, and the inner sides of the limiting pieces extend radially; When the conical spiral diaphragm is compressed along the axial direction of the stent body, the spiral layers of the conical spiral diaphragm are closed, and the outer side of the second bottom spiral layer is supported on the inner side of the limiting piece to prevent the bottom of the conical spiral diaphragm from reverse deformation.

2. The bile duct stent according to claim 1, characterized in that: Two or more protrusions are provided on the inner side of the secondary bottom spiral layer, and the circumferential positions of the protrusions are the same as those of the limiting pieces; the protrusions are used to support the upper spiral layer when the conical spiral diaphragm is compressed.

3. The bile duct stent according to claim 2, characterized in that: The bottom spiral layer is provided with three limiting pieces at intervals.

4. The bile duct stent according to claim 3, characterized in that: The thickness of the two spiral layers at the bottom of the conical spiral diaphragm is smaller than the thickness of the spiral layer at the top of the conical spiral diaphragm.

5. The bile duct stent according to claim 1, characterized in that: The elastic metal wire is made of beryllium copper alloy or nickel titanium alloy.

6. The bile duct stent according to claim 1, characterized in that: The front end of the bracket body is a trumpet mouth that expands toward the periphery.

7. The bile duct stent according to claim 1, characterized in that: From the bottom layer to the top layer, the radial width of each spiral layer of the conical spiral diaphragm gradually decreases.

8. The bile duct stent according to claim 1, characterized in that: The limiting piece is made of polytetrafluoroethylene or polyetheretherketone.

9. The bile duct stent according to claim 1, characterized in that: Two or more metal markers are respectively provided at both ends of the bracket body, and the metal markers are used to assist image positioning.

10. The bile duct stent according to claim 1, characterized in that: The length of the stent body is 6-10 mm.

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