KR20080078265A - Expandable stent having check valve therein - Google Patents

Abstract

A contractile and expandable stent having a cylindrical check valve at the inside is provided to secure a passage for fluid such as food and to remove a side effect caused by a backflow by installing the sleeve check valve at the inner side. A contractile and expandable stent inserted into the internal cavity of living bodies is composed of: a cylindrical wire meshed structure produced by plaiting one or more wires or crossing the wires across each other in zigzag; a coating film(2) made of biocompatible elastic polymer being applied on the wire meshed structure; and a backflow preventing check valve(3) formed in the shape of a cylindrical sleeve and joined along the cylinder formed at an inner upper end(4) of the wire meshed structure. Diameters of both ends of the wire meshed structure are expanded larger than a diameter of a body.

Description

Expandable Stent having Check Valve therein

1 is a front view of a conventional stent having only a wire mesh structure as a component.

2 is a perspective view of a conventional stent with a protruding sleeve valve.

Figure 3 is a state diagram of the stent of Figure 2 installed in the esophagus and stomach lumen.

4 is a cross-sectional view of a conventional stent including an "S" shaped check valve inside the stent.

5 is a front view of a stent in accordance with the present invention.

6 is a schematic diagram of a stent of the present invention including a cylindrical sleeve valve therein.

The present invention relates to a stent for securing a fluid passageway such as food by inserting into a patient narrowed by the lumen of the human body. More specifically, the present invention provides a stent including a wire meshed struture of a cylindrical shape, a biocompatible elastomeric film surrounding the mesh structure, and a check valve for preventing backflow, wherein the stent includes an inflation-resistant expansion- For a collapsible stent.

In general, the stent is a structure used to widen the lumen of the organ or blood vessel narrowed due to disease, trauma, surgery, and the like. That is, the stent acts as an internal brace structure in which the lumen is no longer narrowed by being inserted into the stenosis of the patient in which the lumen is constricted due to the narrowing of the lumen or the stenosis is in progress. It is used to secure passages for fluid to pass through.

Conventionally, patients who have blocked or esophageal esophagus due to stenosis due to cancer tissues have been treated mainly through surgical surgery, but these surgical methods are not only satisfactory to the patient but also have unsatisfactory surgical effects. There was a downside.

As an alternative to solve the problems of the surgical method, a procedure using a stent has been developed. That is, by inserting a wire mesh structure (stent, see Figure 1) to the stenosis patient is inserted into the stricture site, the inserted mesh structure serves as a physical support structure against the stenosis pressure, food and the like To provide a fluid passageway.

However, in such a wire mesh structure, there is a limit to the function as a stent to secure a passage of fluid in the stenosis of a patient. That is, a problem arises in that body fluids such as food or bile passing through the stent are deposited or grown on the mesh structure, and the cancer cells escape from the gaps of the mesh structure and invade the lumen, thereby filling the passage of the mesh structure again.

Therefore, in order to overcome the problem of cancer cells being pushed through the mesh structure and invading the lumen, a stent in which the biocompatible elastic resin is coated on the mesh structure is used. The stent coated with the biocompatible elastic resin formed a film in the space between the wire mesh structures to overcome the problem of food, body fluids, or cancer cells being pushed between the mesh structures to prevent the lumen again.

However, in the case of a stent without a contraction-expansion function, there is a problem in that the patient suffers severely during insertion into the lumen of the patient, and the foreign body feels severe even after insertion. In order to solve this problem, a contraction-expandable stent that contracts by an external force and expands itself when the external force is removed is used.

That is, the contraction-expandable stent is inserted into a constriction site such as the esophagus while the volume thereof is significantly reduced by using an insertion means, and the stent separated from the insertion means is expanded and returned to its original state by its elastic force. By pushing out the narrowing part of the body, the passageway expands in the lumen.

By the way, when the stenosis is the esophagus site connected to the stomach, that is, the sphincter site to adjust the narrowing and expansion of the esophagus, the stent to maintain the swelling of the esophageal and gastric sphincter site as well as pathological stricture site Will always be open. Through the open stent and the stent to maintain the stomach, the food inside the stomach (胃) is refluxed through the esophagus, the acid flow back with the food has a problem that damage the esophagus.

In order to solve this problem, stents have been disclosed to prevent backflow by having a flexible tube connected to the bottom of the stent positioned inside the stomach (US Pat. Nos. 5,861,036 and 6,302,917 B1, Japanese Patent Laid-Open). 9-32933, etc.).

However, the conventional technology described above has a problem in that the backflow prevention tube is made of a flexible material, as shown in FIGS. 2 and 3, causing foreign matter or pain that is rubbed on the inner wall of the stomach wall while flowing in the stomach. Moreover, a sleeve valve protruding into the gastric lumen to increase the anti-backflow effect caused serious side effects of closing the duodenum, resulting in a recall case.

On the other hand, in order to solve the problem of the valve of the non-return valve protruding form has been disclosed an invention in which the check valve is installed inside the stent. One of them is a stent disclosed in the Republic of Korea Patent No. 442330, which has an S-shaped backflow prevention device having a checkered cross section in the shape of a taegeuk pattern.

However, the patented stent requires a molding operation by a precise mold in the process of producing the valve structure, which makes it difficult to manufacture the mold, resulting in an increase in manufacturing cost and an increase in defective rate. In addition, the relatively thick valve blade has a disadvantage in that flexibility is reduced, so that the back flow occurs to the "S" gap of the valve, and as a result, the purpose of preventing the back flow of the check valve is not completely achieved.

As described above, the prior arts have tried to make stents capable of minimizing side effects and performing a backflow prevention function, but still do not completely overcome these problems.

Therefore, the inventors have shown that, as shown in FIG. 7, the cylindrical wire mesh structure 1, the biocompatible elastomeric film 2 covering the mesh structure 1, and the upper surface of the inner surface of the wire mesh structure 1. To focus on the stent including the check valve (3) of the cylindrical sleeve shape as a backflow prevention means joined along the circumference of the cylinder (4), to complete the stent easy to manufacture and low-cost production while performing the backflow prevention function Reached.

The stent according to the present invention has the industrial advantage of being very economical because of solving most of the problems of the prior art as described above, as well as ease of manufacture and low cost.

Accordingly, a basic object of the present invention is a shrink-expandable stent for forming a fluid passage in a stricture or occluded living lumen, in which a contraction of a cylindrical backflow check valve structure is formed inside the stent to eliminate side effects of the conventional stent. To provide an expandable stent.

The basic object of the present invention described above is a cylindrical wire meshed structure (1) prepared by weaving or zigzag crossing one or more strands of wire with each other, and a biocompatible elastomeric polymer covering the wire mesh structure. By providing a retractable expandable stent comprising a coating (2) and a backflow preventive check valve structure (3) shaped like a cylindrical sleeve joined along the circumference of the top of the inner surface of the wire mesh structure. Can be.

The wire mesh structure is generally cylindrical in shape. The wire mesh structure preferably uses a wire made of a shape memory alloy.

The wire mesh structure of the present invention includes all the mesh structures known to those skilled in the art, but preferably, the wire mesh structure can be manufactured in a compact and time-consuming manner while simplifying the manufacturing operation. According to the bending shape of the flexural flexion without bending can not only greatly improve the partial expansion force in the bending portion but also have a mesh structure that does not move easily in the inserted position of the lumen.

Hereinafter, a wire mesh structure that can be applied to the present invention will be described as a specific example. However, the following examples are not intended to limit or limit the scope of the present invention to the contents described therein.

As a first example of the wire mesh structure that can be applied to the present invention (hereinafter referred to as 'first mesh structure'), the first unit member and the second unit member each formed in a unit length and the second unit member One unit member is rotated in a zigzag with a certain period of time based on a constant reference point to form a cylindrical structure to form a first one turn, and after the formation of the first one turn, the phase difference in the first one turn Corresponding to each other to form a mesh structure while rotating one zigzag to form a first Eaton, the second unit member is a reference point having a predetermined distance in the longitudinal direction at the point facing the reference point of the first one turn In addition, at a constant phase difference from the first one turn, the first one turn and the first eater are regularly intersected to form a mesh structure and rotate one zigzag. To form a second one turn, and after the formation of the second one turn, the second one turns to interfere with each other with a phase difference to form a mesh structure and between the first one and the first eaton. It crosses constantly and forms a mesh structure, and rotates one zigzag to form a second eaten.

In the first mesh structure, the first one-turn and the first-turn may include first straight lines and first straight lines formed by a plurality of bending points, and the first straight lines. And a plurality of first one-peak portions, a first two-peak portion, a first one-valley portion, and a first two-valley portion connecting the first straight line portions, respectively, the first straight portion and the first straight portion. 1 straight line portion intersects to form a mesh, wherein the second one turn and the second turn are second straight lines and second straight lines formed by a plurality of bending points, and the second straight line. And a plurality of second one-peak portions, a second two-peak portion, a second one-valley portion, and a second two-valley portion connecting the straight portions and the second straight portions of, respectively; The second and second straight line portions intersect to form a mesh and the second one, straight line portion One of the first, the cross-line portion and the turnover can form a mesh.

In the first mesh structure, the first unit member is twisted at least once along the first straight portion of the first one turn after forming the first eat and before forming the second one turn. The second unit member may be twisted at least one or more times along the second straight portion of the second one turn before the second unit member is formed and before forming the first one that is adjacent to the second one. Can be.

In addition, in the first mesh structure, the first work, the first work of the Eaton, the two peak parts and the first work, the Evalley part, the first work, the first work neighboring the Eaton, Eaton's first work, the Evalley part and the first work, the two-peak part is connected to each other, the second work, the second work of Eaton, the two-peak part and the second work, this valley part The second work, the second work neighboring the Eaton, the second work of the Eaton, the Evalley and the second work, can be connected to each other by the two-peak.

In the first mesh structure, the stent is inserted into the stenosis of the lumen to minimize friction with the lumen when it expands and to allow blood or food to flow smoothly. , Coating member for covering the outer surface may be coated.

Further, in the first mesh structure, one end or both ends of the stent have a diameter larger than the diameter of the stent and are integrally connected by a coating member, and when the stent is inserted into the stenosis of the lumen, A movement preventing member may be provided to prevent movement while supporting the stent in the lumen.

The second example of the wire mesh structure that can be applied to the present invention (hereinafter referred to as 'second mesh structure') is formed by a plurality of bending points along the circumferential surface to form a wire having a predetermined unit length to form a cylindrical structure. A first turn formed in one zigzag rotation to have a plurality of peaks and valleys connecting the straight portions to the straight portions; Interference with at least one or more sequential phases in the first turn and intersecting with the straight portion, and different from the other straight portion forming a mesh, and a plurality of other peak portions connecting the other straight portion, respectively And an interference turn formed by sequentially rotating in zigzag to have valley portions.

Further, in the second mesh structure, the valley portions of the first turn and the interference turn may be formed by walking the corresponding peaks of the first turn, the interference turn, and the neighboring first turn and the interference turn.

In the second mesh structure, one end of the interfering turns interfering at least one of the interfering turns may form a connecting portion that is twisted in a spiral at least once in a straight portion of the first turn.

Further, in the second mesh structure, the connection part is firmly coupled to the first turn and the interference turn, and a portion where the straight parts cross each other so that the stent is easily extended in the longitudinal direction when the stent is expanded in the contracted state. At least one or more times may be connected to the twist.

In the second mesh structure, the first turn and the interference turn may be formed at the same period or at different periods.

In the second mesh structure, the first turn and the interference turn may be formed to have the same width or may be formed to have different widths.

In addition, in the second mesh structure, a movement preventing part for firmly fixing the stenosis of the lumen to at least a portion of the first turn or the interference turn and maintaining the fixed state is provided. Can be.

In the second mesh structure, the movement preventing part is integrally formed in a flare shape in which the diameter of the first turn or the interference turn extends outward, or at one end of the first turn or the interference turn. It may be integrally formed to protrude in a direction perpendicular to the central axis of the first turn or interference turn.

 The third example of the wire mesh structure that can be applied to the present invention (hereinafter referred to as 'third mesh structure') has a plurality of bending points along the reference circumferential surface to form a cylindrical unit member having a unit length A plurality of reference turns which are rotated in a zigzag and connected in a latching manner while forming a mesh structure with corresponding portions adjacent to each other; The unit member is connected along the outer circumferential surface of the straight portion of one reference turn in a twisted manner, and includes a main overlap turn that overlaps the reference turn in a double way, and is capable of contracting and expanding on its own and having a constant unit length having flexibility. The unit members reciprocate in a zigzag shape from one end of the reference circumferential surface to the other end and are wound spirally along the reference circumferential surface to cross each other to form a mesh structure, and the unit member and the unit member may cross each other. When filtering 1 to 3 times, by connecting the unit members by twisting each other at this intersection, it can be made to form a cylindrical shape as a whole.

In the third mesh structure, the unit member may include: peak portions formed at one end of the reference circumferential surface; Valleys formed at the other end of the reference circumferential surface; It may be made of a spiral wound around the reference circumferential surface spirally connecting the peaks and valleys to each other.

In the third mesh structure, when the spiral portions intersect with each other, the connecting portion may be twisted to connect the spiral portion and the spiral portion by twisting at least one or more times.

In addition, in the third mesh structure, the connection part may have a single twist while regularly filtering at least one or more crossing portions of the spiral part to ensure expansion while maintaining excellent flexibility and shrinkability.

In addition, in the third mesh structure, preparing a unit member having a predetermined unit length, which is capable of contracting and expanding itself and having flexibility; Zigzags the unit member from one end of the reference circumferential surface to the other end thereof. Forming a mesh structure when the spiral portions intersect while forming a peak portion, a valley portion, and a spiral portion connecting the spiral portions and winding the spiral portion along the reference circumferential surface in a spiral manner. When the spirals intersect with each other in the above step, it may include forming a connection by twisting the intersection portion at least once or more by twisting the spiral portion and the spiral portion.

In addition, in the third mesh structure, the connection part may have a single twist while regularly filtering at least one or more crossing portions of the spiral part to ensure expansion while maintaining excellent flexibility and shrinkability.

A fourth example of a wire mesh structure (hereinafter referred to as a 'fourth mesh structure') that can be applied to the present invention is a cylindrical stent composed of a wire and having a longitudinal axis, wherein the wire is formed into straight portions along a circumferential surface. A plurality of reference turns having a plurality of peaks and valleys connected to each other and having one reference turn formed while zipping in a zigzag direction without an intersection point at intervals equal to the height of the reference turns along the length of the cylinder; The connecting turns connecting the plurality of reference turns to each other in a mesh form by winding the linear portions of the reference turns overlapping while being arranged in the left and right tilt directions are equal to the distance between the reference turn straight portions in the left and right tilt directions. It may be composed of a plurality of connecting turns arranged at intervals.

In the fourth mesh structure, the wire may be made of nitanol which is a shape memory alloy.

In addition, in the fourth mesh structure, the connection turn may cover the straight portions 1a of the reference turn overlapping with each other 2 to 10 times.

The biocompatible elastomeric film 2 of the present invention may be made of polyvinyl chloride (PVC), natural rubber, silicone, polymethyl methacrylate (PMMA), polyurethane (PU), Thermoplastic elastomer (TPE), ethylene-vinyl acetate alcohol polymer (EVAL polymer), polypropylene (PP), polyethylene (PE), acetyl cellulose, polyethylene Terephthalate (polyethyleneterephthalate (PET), or polytetrafluoroethylene (polytetrafluoroethylene, PTFE) may be made of a biocompatible polymer material of any one or a mixture thereof, in addition to the present invention All materials known to those skilled in the art as biocompatible polymer materials are Name wire may be used as the covering material of the mesh structure.

The wire mesh structure 1 and the polymer film 2 coated thereon are contracted by an external force, and when the external force is removed, the wire mesh structure 1 has a property of self-expansion, that is, elasticity. It is inserted into the lesion site of the esophagus in the state, and the stent separated from the insertion means is expanded and returned to its original state by elastic force to push the constriction of the esophagus outward to expand the passage. At the same time, the check valve attached to the inside of the stent also maintains the tube shape while expanding and returning with the elastic stent.

The stent installed as described above expands the constricted lesion site and smoothly delivers the food taken through the mouth to the stomach through the stent and the backflow prevention tube.

The check valve 3 is for preventing the backflow, which is a basic object of the present invention. The check valve 3 has a cylindrical sleeve shape as shown in FIG. 7, and the upper end of the inner surface of the wire mesh structure so as not to protrude out of the stent. A circular joint 4 is formed and attached along the cylinder of 4).

The conventional technique is that the backflow tube made of a flexible material flows in the lumen of the stomach and causes pain by stimulating the inner wall of the stomach wall. Recall was also performed on the stent according to the prior art, causing side effects of closure.

The stent according to the present invention is invented to eliminate the disadvantages of the conventional stent as having a cylindrical sleeve inserted into the wire mesh structure (1).

Still another object of the present invention is to provide a stent including a check valve made of a thin membrane in the shape of a cylindrical sleeve which reduces production cost and effort while performing a backflow prevention function.

Still another object of the present invention is characterized in that the check valve can have an additional fixing point 5 in the middle of the stent so as to select whether to allow limited backflow for vomiting or the like according to the condition of the patient. To provide a stent.

It is still another object of the present invention to provide a stent with an extended end shape that allows the stent to be more stably inserted into the living body lumen, and facilitates the flow of fluid in a mounted state.

In addition, the check valve 3 of the present invention has a simple cylindrical sleeve shape, so it is very easy to manufacture. That is, since it does not require an elaborate mold for the manufacture of the check valve, it is possible to reduce the effort or cost, and the defective rate of the product is significantly reduced.

In addition, the cylindrical sleeve valve 3 can easily adjust the degree of prevention of backflow according to the length of the sleeve, it is possible to perform a near-backflow prevention function.

In the cylindrical sleeve, no reverse flow occurs under normal pressure from the lumen of the human body, but inverting the cylindrical sleeve to the outside of the esophagus when the pressure in the esophageal direction is applied to a certain level of back pressure, ie, the lumen, is inverted. Occurs, in which case the stent of the present invention allows exceptional backflow. That is, the patient is allowed to restrict the backflow in the case of the back pressure due to vomiting or belching.

Furthermore, whether to allow the limited backflow can be selected depending on whether the following fixed points 5 are formed. That is, the cylindrical sleeve 3 is attached to the wire mesh structure 1 in addition to being attached to the wire mesh structure 1 by forming a joining portion 4 along the cylinder at the upper end of the inner surface of the wire mesh structure 1. In addition, by forming a fixed point (5) that draws a circle along the cylinder of the inner surface of the wire mesh structure may not allow backflow even if the back pressure due to vomiting, etc. act.

For example, allowing simple reflux for vomiting or burping may be more comfortable for patients with simple esophageal strictures, but for patients with unconscious or impending death, reflux due to vomiting or burping may be possible. Since it is meaningless and only a perfect backflow prevention function is required, the wire mesh structure is formed in addition to forming the joint portion 4 for attachment of the wire mesh structure 1 and the cylindrical sleeve valve 3. (1) Insert a stent that completely blocks backflow by further forming a fixed point that draws a circle along a cylinder of the inner surface at a position below the junction 4 at the upper end of the inner surface.

Another object of the present invention described above can be achieved by providing a stent in which the cylindrical sleeve valve 3 is composed of a thin membrane biocompatible polymer material. The cylindrical sleeve valve 3 of the present invention is made of a biocompatible elastomeric material, that is, polyvinyl chloride (PVC), natural rubber, silicone, polymethly methacrylate (PMMA), polyurethane ( polyurethane, PU), thermoplastic elastomer (TPE), ethylene-vinyl acetate alcohol polymer (EVAL polymer), polypropylene (PP), polyethylene (PE), acetyl cellulose (acetyl) cellulose), polyethylene terephthalate (PET), or polytetrafluoroethylene (polytetrafluoroethylene, PTFE), or any one or a mixture thereof. It is known to those skilled in the art as a biocompatible polymer material. Any material known can be used as the cylindrical sleeve valve 3 of the present invention.

The thin-walled cylindrical sleeve valve 3, preferably a cylindrical sleeve valve made of silicone, makes it possible to more effectively carry out the backflow prevention function which is the basic object of the present invention.

Another object of the present invention described above can be achieved by providing a stent, characterized in that the diameter of both ends of the mesh wire structure (1) is larger than the diameter of the body.

The mesh wire structure 1 is characterized in that it is extended at both ends than the diameter of the body, preferably 15% to 25%, and discontinuously expanded. The end having the expanded diameter increases the sense of stability at the position inserted into the patient, and facilitates the flow of food and the like.

In the stent of the present invention, the narrowing of the lumen of the human body allows the patient to be inserted into the lumen of the patient, thereby securing a passage of fluid such as food, and having a sleeve-type check valve as a backflow prevention means in the stent. Side effects were eliminated. On the other hand, the stent of the present invention was to allow the limited reflux for vomiting, etc. according to the condition of the patient to be selected to provide optimal comfort to the patient inserted the stent.

In addition, the present invention provides a stent having an increased industrial use value by significantly lowering a defect rate as well as a reduction in production cost due to its ease of manufacture.

Claims (6)

1. A shrink-expandable stent inserted into an organism lumen, comprising: a cylindrical wire meshed struture (1) made by weaving or zigzag crossing one or more strands of wire together; A film (2) made of a biocompatible elastomeric polymer material covering the wire mesh structure (1); And a non-return check valve (3) in the shape of a cylindrical sleeve joined along a cylinder at the top of the inner surface of the wire mesh structure (1). The stent according to claim 1, wherein the mesh wire structure (1) has a diameter at both ends of the stent being larger than the diameter of the main body. The stent of claim 1, wherein the elastic polymer film 2 is made of polyvinyl chloride (PVC), natural rubber, silicone, polymethyl methacrylate (PMMA), or polyurethane (polyurethane). , PU), thermoplastic elastomer (TPE), ethylene-vinyl acetate alcohol polymer (EVAL polymer), polypropylene (PP), polyethylene (PE), acetyl cellulose ), Polyethylene terephthalate (polyethyleneterephthalate, PET), and polytetrafluoroethylene (polytetrafluoroethylene, PTFE) any one or a mixture thereof selected from the group consisting of a stent. The stent of claim 1, wherein the check valve (3) is made of polyvinyl chloride (PVC), natural rubber, silicone, polymethly methacrylate (PMMA), polyurethane (polyurethane, PU), thermoplastic elastomer (TPE), ethylene-vinyl acetate alcohol polymer (EVAL polymer), polypropylene (PP), polyethylene (PE), acetyl cellulose , Polyethylene terephthalate (polyethyleneterephthalate, PET), and polytetrafluoroethylene (polytetrafluoroethylene, PTFE) is a stent, characterized in that made of a biocompatible elastic polymer material which is any one or a mixture thereof. Stent according to claim 1, characterized in that the check valve (3) consists of a thin film of 0.1 mm or less. Stent according to claim 1, characterized in that the check valve (3) further has a fixed point (5) along the cylinder of the inner surface of the wire mesh structure (1) below the junction (4).

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