Patent Description:
Generally, a bile duct serves as a passage that allows bile, which is concentrated after being produced by the liver and stored in the gallbladder, to flow to the duodenum. A biliary stricture is a disease in which the bile duct is constricted and the passage is narrowed or blocked due to tumors such as pancreatitis/pancreatic cancer and cholangitis/cholangiocarcinoma.

A biliary stricture can be treated with surgery, but endoscopic biliary stenting has been used in recent years. In particular, stenting is widely practiced when surgery is not possible due to the onset of a malignant biliary stricture in terminal cancer patients.

However, regarding the conventional bile duct stent, a problem has been pointed out in that food passing through the duodenum frequently flows back into the bile duct, obstructing the flow of bile and causing side effects due to cholangitis or stent malfunction.

In order to address such a problem, a bile duct stent having a backflow preventing means has been proposed in the past, but it is difficult to prove its effectiveness due to various shortcomings.

For example, <CIT> discloses a stent having a backflow preventing means formed of tricuspid valve/ tricuspid valve type valves made of a resin material.

However, the valves disclosed in <CIT> have a disadvantage in that, when an expansile force of the stent is weak or when the stent does not maintain a sufficiently expanded state, openings of the valves are not sufficiently opened and reach a closed state, thus obstructing the supply of bile and causing solidification of stagnant bile. In addition, since the backflow preventing means is made of a resin material, there is a disadvantage in that durability is lowered due to an occurrence of film damage caused by bile as in the conventional tubular stent.

Therefore, there is a need for ways to address the conventional backflow prevention problem and secure durability to expand the effects of stent placement in the bile duct.

Matters described in the "Background Art" section are intended to enhance understanding of the background of the invention and may include matters that are not related art already known to those of ordinary skill in the art to which the present invention pertains.

<CIT> discloses a biliary stent, wherein a diameter of the end of the biliary stent facing a duodenum is minimized by forcing the end of the end of the biliary stent facing the duodenum by using a medical thread, so that the stent is placed in the biliary tract facing the duodenum.

<CIT> discloses a stent including a cylindrical outer stent, and a downwardly tapered inner stent covered with a polytetrafluoroethylene (PTFE) or silicone coating having biocompatibility, wherein the inner and outer stents are coupled to each other to define a double structure.

Embodiments of the present invention are directed to providing a bile duct stent, in which a backflow-preventing pattern film utilizing a pattern member made of metal wires is formed at a duodenum-side outlet of the stent, which is inserted into the bile duct, to prevent food in the duodenum from flowing back into the bile duct, and a method of manufacturing the same.

According to embodiments of the present invention, by forming various backflow-preventing pattern films using a pattern member made of metal wires at a duodenum-side outlet end of a cylindrical body of a bile duct stent, there is an effect of preventing the backflow of food into the stent (the bile duct).

Also, backflow-preventing pattern films of various dense patterns can be easily manufactured with metal wires on an outlet end of the bile duct stent, and by configuring the backflow-preventing pattern films using nylon threads or metal wires, there is an effect of securing durability.

In addition, by forming a radial backflow-preventing pattern film, which has a bent portion formed at the center, using metal wires having a self-expansile force, there is an effect of facilitating diameter reduction of the bile duct stent when loading the bile duct stent on a catheter. Further, there is an effect of allowing the backflow preventing performance to be maintained regardless of whether any deformation occurs in the cylindrical body of the stent due to pressure on a lesion site.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings to allow those of ordinary skill in the art to which the present invention pertains to easily carry out the invention. However, the present invention may be implemented in various different forms and is not limited to the embodiments described herein. Also, in the drawings, parts unrelated to the description have been omitted to clearly describe the present invention, and like parts are denoted by like reference numerals throughout the specification.

Throughout the specification, when a certain part is described as "including" a certain element, unless otherwise stated, this does not exclude the inclusion of other elements but in fact the certain part may further include other elements. Also, terms such as "portion," "-er/or," and "module" indicate units of processing at least one function or operation.

Throughout the specification, terms such as "first" or "second" may be used to describe various elements, but the elements are not limited by the terms. The terms are only used for the purpose of distinguishing one element from another element. For example, without departing from the scope of rights according to the concept of the present invention, a first element may be referred to as a second element, and likewise, a second element may also be referred to as a first element.

Now, a bile duct stent and a method of manufacturing the same according to embodiments of the present invention will be described in detail with reference to the drawings.

<FIG> is a conceptual diagram illustrating a state in which a bile duct stent according to an embodiment of the present invention is placed.

Referring to <FIG>, a state in which a bile duct stent <NUM> according to an embodiment of the present invention is inserted into the bile duct connected to the duodenum is shown.

The bile duct stent <NUM> has a cylindrical mesh structure formed using metal wires and has self-elasticity and thus contracts when an external force is applied thereto and expands when the external force is removed.

Through stenting, the bile duct stent <NUM> is inserted into a luminal lesion site where a biliary stricture has occurred. The bile duct stent <NUM> expands a lumen by its self-expansile force and maintains the lumen in an expanded state so that the lumen is not narrowed again, and in this way, the bile duct stent <NUM> serves to facilitate the flow of bile in the duodenum.

In the previous description, it has been pointed out that, in the conventional stent structure, food passing through the duodenum may flow back into the expanded bile duct, and when the food flows back into the stent, the flow of bile may be obstructed and various problems may occur.

Thus, embodiments of the present invention are directed to providing a bile duct stent, in which a backflow-preventing pattern film is formed by weaving a pattern member made of metal wires with a duodenum-side outlet end that is inserted into the bile duct to prevent the backflow of food from the duodenum into the bile duct, and a method of manufacturing the same.

Hereinafter, in describing the bile duct stent and the method of manufacturing the same according to the present invention, a stent with a backflow-preventing pattern film of various patterns according to the type of the pattern member and a method of manufacturing the same will be described in detail below according to various embodiments.

First, a stent with a backflow-preventing pattern film using threads and a method of manufacturing the same will be described according to a first embodiment.

<FIG> illustrates a state in which a bile duct stent is manufactured using a jig according to a first configuration not covered by the claimed invention.

Referring to <FIG>, a bile duct stent <NUM> (hereinafter referred to as "stent" for convenience) according to the first configuration not covered by the claimed invention is manufactured by zigzagging metal wires <NUM> on a plurality of pins P disposed in a circumferential direction X and a longitudinal direction Y of a cylindrical jig <NUM>.

The stent <NUM> may be manufactured to have a cylindrical body <NUM> whose diameter is in a range of <NUM> to <NUM> and a length is in a range of <NUM> to <NUM>, but the stent <NUM> is not limited thereto and may be made to order by extending the length of the jig <NUM> according to the size of a lesion site of a patient.

The metal wires <NUM> is made of a shape memory alloy such as nitinol to allow a certain expansile force to act at a certain temperature as in the lumen of the bile duct, but other known stent-manufacturing wires may be utilized as the metal wires <NUM>.

The metal wires <NUM> form zigzag patterns by being woven in the circumferential direction X in which the plurality of pins P are disposed at certain intervals, and the stent <NUM> having the cylindrical body <NUM> having a mesh structure in which the zigzag patterns formed in the circumferential direction X intersect each other while interfering with each other and are arranged at predetermined intervals W in the longitudinal direction Y is manufactured. The cylindrical mesh structure of the stent <NUM> is shown as having a shape in which rhombic patterns, each with all four sides the same length, are arranged in the circumferential direction X and the longitudinal direction Y of the stent <NUM>.

For example, <FIG> is a development view illustrating a weaving structure of a stent body according to the configuration not covered by the claimed invention.

The metal wires <NUM> according to the configuration not covered by the claimed invention include first metal wires 11a and second metal wires 11b each of which is able to contract and expand by itself, has flexibility, and is formed to have a unit length.

Referring to <FIG>, a state in which zigzag patterns of the first metal wires 11a and the second metal wires 11b are woven while interfering with each other to form rhombic patterns and are each rotated twice is shown.

Here, vertical intersection points of a checkerboard shape formed by dotted lines are positions of holes H where the pins P are inserted into the jig <NUM>, and round points at the intersection points indicate a state in which the pins P are installed in the holes H. In the state in which the pins P are disposed in the jig <NUM>, the first metal wires 11a and the second metal wires 11b are woven to manufacture the cylindrical body <NUM> having the mesh structure.

Also, the first metal wires 11a and the second metal wires 11b are configured to be bent due to the pins P and to only intersect each other without being twisted. In this way, flexibility can be secured, and an easily collapsible structure can be secured upon loading on a catheter afterwards.

A passage of the cylindrical body <NUM> is directed according to a direction in which bile flows in the bile duct, and an upper end of the passage that is formed at the liver or gallbladder side is defined as an inlet end (IN) while a lower end of the passage that is formed at the duodenum side is defined as an outlet end (OUT).

Here, in the stent <NUM> according to the configuration not covered by the claimed invention, a backflow-preventing pattern film <NUM> formed of a network structure using nylon threads <NUM> is formed at the duodenum-side outlet end (OUT) of the cylindrical body <NUM> that is inserted into the bile duct, and in this way, the backflow of food from the duodenum into the bile duct is prevented.

The overall process of manufacturing the stent <NUM> according to the first configuration not covered by the claimed invention includes a step in which the metal wires <NUM> are woven through the jig <NUM> and then heat-treated to form the cylindrical body <NUM> having elasticity, a step in which the cylindrical body <NUM> separated from the jig <NUM> is fitted to a film jig (not illustrated) and coated with a silicone coating solution and then dried to form a silicone film portion <NUM>, and a step in which the threads <NUM> are woven to the outlet end of the cylindrical body <NUM> to manufacture the backflow-preventing pattern film <NUM> having a network structure.

For example, <FIG> illustrates an example of manufacturing a cross-shaped backflow-preventing pattern film using threads according to the first configuration not covered by the claimed invention.

Referring to <FIG>, the stent <NUM> according to the first configuration not covered by the claimed invention may be manufactured so that a diameter of the outlet end of the cylindrical body (e.g., <NUM>) is greater than a diameter of the central portion thereof (e.g., <NUM>). <FIG> shows a state in which the silicone film portion <NUM> is formed on the cylindrical body <NUM>. Here, from an enlarged view of the bottom surface of the outlet end of the cylindrical body <NUM>, it can be seen that cells made of the metal wires <NUM> are arranged in a circular shape about the center like petals of a sunflower.

Here, a hole h is formed in the silicone film portion <NUM> of each cell formed at the outlet end of the cylindrical body <NUM>.

The backflow-preventing pattern film <NUM> may be formed to have a network structure by repeating a process in which the thread <NUM> fixed by zigzagging to the cell made of the metal wires <NUM>, which is formed in the circumferential direction through any one hole h at a start point, crosses the outlet end one time or more, and passes through another hole h.

For example, looking at the process of manufacturing the cross-shaped backflow-preventing pattern film <NUM> in detail with reference to <FIG>, the thread <NUM> passes through a first hole h1 from a start point (Start) and then crosses the outlet end and passes through a second hole h2 (S1), passes through a third hole h3 of a cell made of the metal wires <NUM>, which is formed in the circumferential direction, to be woven to another thread <NUM> so that the threads <NUM> interfere with each other (S2), passes through a fourth hole h4 and then crosses the outlet end and passes through a fifth hole h5 (S3), then passes through a sixth hole h6, which is formed in the circumferential direction, and then is knotted at an end point (End) (S4).

In this way, with one task, the thread <NUM> may sequentially pass through the holes h of the silicone film portion <NUM>, which is formed on each cell, from the start point (Start) and be woven as if stitched to the cells made of the metal wires <NUM> to form the cross-shaped backflow-preventing pattern film <NUM> at the outlet end and then may be knotted at the end point (End) which is the same as the start point (Start).

Meanwhile, the backflow-preventing pattern film <NUM> according to the first configuration not covered by the claimed invention is not limited to the cross-shaped backflow-preventing pattern film <NUM> described above, and backflow-preventing patterns of various other forms may be applied.

For example, <FIG> illustrates an example of implementing various backflow-preventing pattern films using the threads according to the first configuration not covered by the claimed invention.

Referring to <FIG>, hereinafter, since backflow-preventing patterns #n according to various embodiments may be applied to the backflow-preventing pattern film <NUM> according to the configuration not covered by the claimed invention, like "<NUM>#n," The examples of <FIG> are not covered by the invention as defined in the appended claims. the reference numeral of the backflow-preventing pattern film <NUM> and the reference numeral of the backflow-preventing pattern #n will be combined to distinguish the backflow-preventing pattern films <NUM> having different patterns.

That is, in addition to the above-described cross-shaped backflow-preventing pattern film <NUM>#<NUM>, the backflow-preventing pattern film <NUM> may be formed as backflow-preventing pattern films <NUM> having various other patterns such as a straight backflow-preventing pattern film <NUM>#<NUM>, a zigzag-shaped backflow-preventing pattern film <NUM>#<NUM>, a V-shaped backflow-preventing pattern film <NUM>#<NUM>', a polygonal backflow-preventing pattern film <NUM>#<NUM>, and a star-shaped backflow-preventing pattern film <NUM>#<NUM> in which the thread <NUM> is woven between a hole h and another hole h and crosses the outlet end.

In this way, the stent <NUM> according to an configuration not covered by the claimed invention may be manufactured to have various backflow-preventing pattern films <NUM> according to ways in which the thread <NUM> is utilized and woven to the outlet end (OUT) of the cylindrical body <NUM>. During placement of the stent <NUM>, in a state in which the stent <NUM> is developed at a lesion site in the bile duct, the thread <NUM> forms a network structure of the backflow-preventing pattern. In this way, the stent <NUM> has an effect of preventing the backflow of food from the duodenum into the bile duct.

Also, the backflow-preventing pattern film <NUM> may be manufactured by stitching and weaving the thread <NUM> with a needle passing through the silicone film portion <NUM> formed on the periphery of the outlet end.

Since the backflow-preventing pattern film <NUM> is manufactured using threads, the stent <NUM> can be easily loaded on a catheter without difficulty of reducing the diameter of the stent <NUM>, and since, during placement of the stent <NUM>, the stent <NUM> is unfolded especially to have a pattern simultaneously as the cylindrical body <NUM> develops at a lesion site of the bile duct, the stent <NUM> has an effect of preventing the backflow of food from the duodenum into the bile duct.

Meanwhile, the pattern member of the backflow-preventing pattern film <NUM> of the stent <NUM> according to the configuration not covered by the claimed invention can be manufactured by utilizing the metal wires <NUM> as well as the threads <NUM>, and a method of manufacturing the backflow-preventing pattern film <NUM> using the metal wires <NUM> will be described in detail below according to another embodiment.

<FIG> illustrates a state in which a bile duct stent is manufactured using a jig according to a second configuration not covered by the claimed invention.

Hereinafter, since structures of a jig <NUM> and a stent <NUM> manufactured according thereto according to the second configuration not covered by the claimed invention are similar to those in the first embodiment described above, overlapping description will be omitted, and differences from the first embodiment will be mainly described.

Referring to <FIG>, in the stent <NUM> according to the second configuration not covered by the claimed invention, a backflow-preventing pattern film <NUM> using metal wires <NUM> is formed at the duodenum-side outlet end (OUT) of the cylindrical body <NUM> that is inserted into the bile duct, and in this way, the backflow of food from the duodenum into the bile duct is prevented.

The overall process of manufacturing the stent <NUM> according to the second configuration not covered by the claimed invention is different from that according to the first embodiment in that, in a state in which the metal wires <NUM> are woven through the jig <NUM> to form the cylindrical body <NUM>, the backflow-preventing pattern film <NUM> using the metal wires <NUM> is formed at the outlet end (OUT) and then heat-treated so that the cylindrical body <NUM> having elasticity and the backflow-preventing pattern film <NUM> are simultaneously manufactured. Then, the cylindrical body <NUM> of the stent <NUM> that is separated from the jig <NUM> is fitted to a silicone film jig (not illustrated) and coated with a coating solution and then dried to complete the manufacturing process.

The backflow-preventing pattern film <NUM> may be formed as the cross-shaped backflow-preventing pattern film <NUM>#<NUM> in which the metal wires <NUM> are woven between a pin P and another pin P, which are disposed in the circumferential direction X at one end (that is, a lower end) of the jig <NUM>, and cross the outlet end (OUT) and intersect each other. Here, pins P1 to P12 disposed in the circumferential direction X at the lower end of the jig <NUM> are almost collinear with the outlet end at the one end surface.

Specifically, in order to form the cross-shaped backflow-preventing pattern film <NUM>#<NUM>, the metal wires <NUM> are knotted by twisting at least once or more after a first line 13a crossing the outlet end from a first pin P1, which is a start point (Start), is woven on a seventh pin P7 and extends and moves <NUM>° to a tenth pin P10 in the circumferential direction X, and then a second line 13b crossing the outlet end (OUT) from the tenth pin P10 vertically intersects the first line 13a and is woven on a fourth pin P4, which is an end point (End). In the above process, the metal wires <NUM> may be twisted one time or more with the metal wire <NUM> forming the outlet end when being woven on each pin P and may be fixed to interfere with each other.

In this way, by one line of the metal wires <NUM> being continuously woven from the first pin P1, which is the start point (Start), to the fourth pin P4, which is the end point (End), and then being finished with a twist knot to another line, the backflow-preventing pattern film <NUM> can be easily manufactured. Further, since it is possible to first manufacture the cylindrical body <NUM> from the inlet end (IN) to the outlet end (OUT) through the jig <NUM> and then form the backflow-preventing pattern film <NUM> using the metal wires <NUM> at the outlet end (OUT) without a pause, there is an advantage in that the manufacturing process is reduced.

When the task of weaving the metal wires <NUM> to the backflow-preventing pattern film <NUM> is completed on the jig <NUM> as described above, the stent <NUM> may be separated from the jig <NUM> and undergo washing and sterilizing processes and then may be shipped out as a finished product. Here, a process of coating the cylindrical body <NUM> with a coating material and forming the film portion <NUM> may be further performed on the stent <NUM>, and then the stent <NUM> may be shipped out as a covered-type metal stent product. The film portion <NUM> may be formed by coating the cylindrical body <NUM> with a coating solution such as polyurethane in a state in which the stent <NUM> is heated to a certain temperature.

Meanwhile, the backflow-preventing pattern film <NUM> using the metal wires <NUM> according to the second configuration not covered by the claimed invention is not limited to the cross-shaped backflow-preventing pattern film <NUM>#<NUM> described above, and backflow-preventing patterns of various other forms may be applied.

For example, <FIG> illustrates an example of implementing various backflow-preventing pattern films using metal wires according to the configuration not covered by the claimed invention.

Referring to <FIG>, the backflow-preventing pattern film <NUM> according to the second configuration not covered by the claimed invention is not limited to the cross-shaped backflow-preventing pattern film <NUM>#<NUM> and may also be formed as the zigzag-shaped backflow-preventing pattern film <NUM>#<NUM>, the polygonal backflow-preventing pattern film <NUM>#<NUM>, and the star-shaped backflow-preventing pattern film <NUM>#<NUM> in which the metal wire <NUM> is woven between a pin P and another pin P and crosses the outlet end.

Referring to <FIG>, the zigzag-shaped backflow-preventing pattern film <NUM>#<NUM> may be formed by the metal wire <NUM> being knotted after crossing the outlet end from an eleventh pin P11, which is a start point (Start), and being woven on a third pin P3, and then sequentially crossing the outlet end and being woven on a ninth pin P9, crossing the outlet end and being woven on a fifth pin P5, and crossing the outlet end and being woven on the eleventh pin P11, which is an end point (End). The start point (Start) and the end point (End) are the same.

Referring to <FIG>, a triangular backflow-preventing pattern film may be formed by the metal wire <NUM> being knotted after crossing the outlet end from the first pin P1, which is a start point (Start), and being woven on the ninth pin P9, and then sequentially crossing the outlet end and being woven on the fifth pin P5, and crossing the outlet end and being woven on the first pin P1, which is an end point (End). Here, the polygonal backflow-preventing pattern film <NUM>#<NUM> may be formed in various other polygonal shapes such as a quadrangular shape in addition to being formed in a triangular shape, and the start point (Start) and the end point (End) are the same.

Referring to <FIG>, the star-shaped backflow-preventing pattern film <NUM>#<NUM> may be formed by the metal wire <NUM> being knotted after crossing the outlet end from the first pin P1, which is the start point (Start), and being woven on an eighth pin P8, and then sequentially crossing the outlet end and being woven on the third pin P3, crossing the outlet end and being woven on the eleventh pin P11, crossing the outlet end and being woven on a sixth pin P6, and crossing the outlet end and being woven on the first pin P1, which is the end point (End).

In addition, the stent <NUM> according to the configuration not covered by the claimed invention may be manufactured to have various backflow-preventing pattern films <NUM> according to ways in which the jig <NUM> is utilized and the metal wire <NUM> is woven to the outlet end (OUT) of the cylindrical body <NUM>. Also, during placement of the stent <NUM>, in a state in which the stent <NUM> is developed at a lesion site in the bile duct, the stent <NUM> has an effect of, by the backflow-preventing pattern film <NUM>, preventing the backflow of food from the duodenum into the bile duct.

Meanwhile, the stent <NUM> may be manufactured to have a denser backflow-preventing pattern film <NUM> with an increase in the number of lines of the metal wire <NUM> that connect a pin P and another pin P and cross the outlet end (OUT). This will be described next according to a third embodiment.

<FIG> illustrates a state in which a bile duct stent is manufactured using a jig having a vertical pin formed thereon according to the present invention.

Hereinafter, since structures of a jig <NUM> and a stent <NUM> manufactured according thereto according to the present invention are similar to those in the second embodiment described above, overlapping description will be omitted, and differences from the second embodiment will be mainly described.

Referring to <FIG>, the jig <NUM> according to the present invention includes at least one vertical pin Py formed on a lower surface <NUM> that corresponds to the outlet end (OUT) of the stent <NUM>.

In the stent <NUM>, the metal wires <NUM> are sequentially woven between the pins P, which are disposed in the circumferential direction X on the lower end of the jig <NUM>, and the vertical pin Py to form a radial backflow-preventing pattern film <NUM>#<NUM> on the outlet end of the cylindrical body <NUM>.

As a specific example, the radial backflow-preventing pattern film <NUM>#<NUM> is formed by, in the clockwise direction, the metal wire <NUM> being woven on the vertical pin Py at the center from a twelfth pin P12 which is a start point (Start) and then being woven on a second pin P2 and extending and moving to the fourth pin P4 in the circumferential direction X (steps S1, S2, and S3), and then being woven on the vertical pin Py at the center from the fourth pin P4 and then being woven on the sixth pin P6 and extending and moving to the eighth pin P8 in the circumferential direction X (steps S4, S5, and S6), and then being woven on the vertical pin Py at the center from the eighth pin P8 and then being woven on the tenth pin P10 which is an end point (End). Here, the steps S3 and S5 for extending and moving may be omitted according to changes in the manufacturing method, and a triangular line connecting a pair of pins and the vertical pin Py may be independently formed. Here, the metal wires <NUM> having the three reciprocating lines woven through the vertical pin Py may be fixed by intersecting each other in a bent state.

Meanwhile, the backflow-preventing pattern film <NUM> may be manufactured to be denser with an increase in the number of lines of the metal wire <NUM> that cross the outlet end (OUT). Thus, the backflow-preventing pattern film <NUM> is not limited to the radial backflow-preventing pattern film <NUM>#<NUM> described above and may be manufactured to have other dense radial backflow-preventing patterns according to various modifications.

For example, <FIG> illustrates various forms of dense radial backflow-preventing pattern films according to the third embodiment.

First, referring to <FIG>, according to the present invention, a first radial backflow-preventing pattern film <NUM>#<NUM> which is denser than the above-described radial backflow-preventing pattern film <NUM>#<NUM> due to an increase in the number of lines of the metal wire <NUM> woven on the vertical pin Py of the jig <NUM> of the stent <NUM> is shown.

Here, in the first radial backflow-preventing pattern film <NUM>#<NUM>, the metal wires <NUM> are more densely sequentially woven between the pins P, which are disposed in the circumferential direction X on the lower end of the jig <NUM>, and the vertical pin Py to form six reciprocating lines that are woven through the vertical pin Py. The six reciprocating lines may be woven with each other and fixed.

Next, referring to <FIG>, not covered by the present invention, as a modification of the first dense radial backflow-preventing pattern film <NUM>#<NUM>, a second radial backflow-preventing pattern film <NUM>#<NUM> is shown which is densely formed by a circular array of vertical pins Py being formed around the center of the lower surface <NUM> of the jig <NUM> and the metal wires <NUM> being woven therethrough.

That is, the metal wires <NUM> may be sequentially woven between six pins P, which are disposed in the circumferential direction X at the lower end of the jig <NUM>, and the array of vertical pins Py corresponding thereto to form dense the second radial backflow-preventing pattern film <NUM>#<NUM> on the outlet end of the cylindrical body <NUM>. The second radial backflow-preventing pattern film <NUM>#<NUM> is not covered by the invention as defined in the appended claims.

In this way, according to the present invention, by utilizing one vertical pin Py formed on the lower surface <NUM> of the jig <NUM>, there is an effect of allowing a radial pattern film, in which lines are denser and disposed at more uniform intervals as compared to the first and second embodiments, to be formed on the outlet end of the stent <NUM>.

Meanwhile, optimal conditions for a bile duct stent in consideration of clinically important physical factors include high flexibility, an excellent radial expansile force, conformability with low axial force to allow the stent to maintain its shape while being bent along the flexion of the bile duct, minimization of a degree of shortening in order to place the stent at a correct position at a lesion site, reduction of a size of a cell between metal wires to reduce growth in a tumor, durability, and a high level of ease of loading the stent on a catheter which is a stent transfer system.

Among the above conditions, the ease of loading the stent on a catheter relates to loading the stent <NUM> in a diameter-reduced state on a catheter to facilitate placement of the stent <NUM>. A structure in which it is difficult to physically reduce the diameter of the stent <NUM> has a disadvantage in that the level of ease of loading is low and a diameter of a catheter is increased, which makes it difficult to insert the catheter into the bile duct and adversely affects the operation carried out by a surgeon.

Here, the bile duct stent <NUM> according to the third embodiment of the present invention has a characteristic in that the radial backflow-preventing pattern films <NUM> of various shapes are formed by the metal wires <NUM> crossing the outlet end. Since such a characteristic may be disadvantageous for diameter reduction, the level of ease of loading the stent <NUM> on a catheter may be considered.

Thus, a bile duct stent <NUM> with a structure in which the level of ease of loading on a catheter is improved will be described next according to a fourth embodiment of the present invention.

<FIG> illustrates a state in which a bile duct stent is manufactured using a conical jig according to the present invention.

<FIG> is a perspective view illustrating a conical backflow-preventing pattern film according to the present invention.

Hereinafter, since structures of a jig <NUM> and a stent <NUM> manufactured according thereto according to the present invention are similar to those in the third embodiment described above, overlapping description will be omitted, and the structure in which the level of ease of loading on a catheter is improved will be mainly described.

Referring to <FIG> and <FIG>, the jig <NUM> according to the present invention includes an outer peripheral surface <NUM>, which is inclined in a conical shape at an outlet end (OUT) of the stent <NUM>, and a vertical pin Py fixed to a vertex of the center of the outer peripheral surface <NUM>.

Also, in the stent <NUM>, a conical backflow-preventing pattern film <NUM>#<NUM> is formed in which the metal wires <NUM> are sequentially woven between the pins P, which are disposed in the circumferential direction X on the lower end of the jig <NUM>, and the vertical pin Py to form a radial pattern, and the center protrudes due to the outer peripheral surface <NUM> inclined in the conical shape. For a specific method of weaving the metal wires <NUM> to form the conical backflow-preventing pattern film <NUM>#<NUM>, the process of manufacturing the radial backflow-preventing pattern film <NUM>#<NUM> that has been described above with reference to <FIG> may be referenced. Further, the conical backflow-preventing pattern film <NUM>#<NUM> may be manufactured to have a denser structure by increasing the number of times the metal wires <NUM> are woven as in <FIG>.

Here, the lines of the metal wires <NUM> forming the conical backflow-preventing pattern film <NUM>#<NUM> form a triangular structure as bent portions 11c are formed due to the vertical pin Py and form an inclined structure in which the bent portions 11c intersect and radiate while interfering with each other.

Meanwhile, <FIG> illustrates an example in which the stent according to the configuration not covered by the claimed invention is placed at a lesion site of the bile duct.

<FIG> shows a state in which the stent <NUM> according to the configuration not covered by the claimed invention is in a diameter-reduced state, loaded on a catheter, and moved past a lesion site in the bile duct.

Here, the conical backflow-preventing pattern film <NUM>#<NUM> is configured so that, when the stent <NUM> is loaded in an inner diameter of a catheter for stent placement, a diameter of the cylindrical body <NUM> is reduced due to an external pressure, and simultaneously, the bent portions 11c are folded without any physical resistance. Thus, there is an effect of facilitating loading of the stent <NUM> on the catheter.

Also, <FIG> shows a state in which the stent <NUM> exposed due to the catheter retracting is expanded, causing the lesion site in the bile duct to be expanded.

Here, the conical backflow-preventing pattern film <NUM>#<NUM> is expanded at a duodenum-side passage of the bile duct to prevent the backflow of food from the duodenum into the bile duct and discharge bile, which flows in the bile duct, to the duodenum.

Meanwhile, <FIG> is a perspective view illustrating a truncated conical backflow-preventing pattern film according to the configuration not covered by the claimed invention.

Referring to <FIG>, the jig <NUM> according to the configuration not covered by the claimed invention includes a truncated cone outer peripheral surface 23a, which is inclined, and a truncated cone lower surface 23b formed at an outlet end (OUT) of the stent <NUM> in order to constitute a truncated conical structure which is broad at the top and gets narrower toward the bottom and also includes a circular array of vertical pins Py formed around the center of the truncated cone lower surface 23b.

Here, in the stent <NUM>, by the metal wires <NUM> being sequentially woven between the pins P, which are disposed in the circumferential direction X at the lower end of the jig <NUM>, and the array of vertical pins Py which correspond to the pins P and are arranged in a circular shape on the truncated cone lower surface 23b, a truncated conical backflow-preventing pattern film <NUM>#<NUM> may be formed on the outlet end of the cylindrical body <NUM>.

Here, in each of the lines of the metal wires <NUM> constituting the truncated conical backflow-preventing pattern film <NUM>#<NUM>, the bent portion 11c may be formed due to the vertical pin Py, and the bent portions 11c may radiate and form an inclined structure without interfering with each other.

In this way, according to the embodiments of the present invention, by forming various backflow-preventing pattern films using a pattern member made of metal wires at a duodenum-side outlet end of a cylindrical body of a bile duct stent, there is an effect of preventing the backflow of food into the stent (the bile duct).

Also, backflow-preventing pattern films of various dense patterns can be easily manufactured with a single line of thread or metal wire on an outlet end of the bile duct stent, and by configuring the backflow-preventing pattern films using nylon threads or metal wires, there is an effect of securing durability.

In addition, by forming a radial backflow-preventing pattern film, which has a bent portion formed at the center, using metal wires having a self-expansile force, there is an effect of facilitating diameter reduction of the bile duct stent when loading the bile duct stent on a catheter. Further, there is an effect of allowing the backflow preventing performance to be maintained regardless of whether any deformation occurs in the cylindrical body of the stent due to a pressure in a lesion site.

Claim 1:
A bile duct stent comprising:
a cylindrical body (<NUM>) having a mesh structure formed by zigzagging metal wires (<NUM>) of a shape memory alloy on a plurality of pins each disposed in a circumferential direction (X) and a longitudinal direction (Y) of a cylindrical jig (<NUM>); and
a backflow-preventing pattern film (<NUM>) in which the metal wires (<NUM>) are woven on pins (P) disposed in the circumferential direction (X) at a lower end of the jig (<NUM>) and the metal wires (<NUM>) cross an outlet end of the cylindrical body (<NUM>) one time or more to form a network structure,
wherein the backflow-preventing pattern film (<NUM>) is formed as a radial backflow-preventing pattern film in which the metal wires (<NUM>) are sequentially woven on the pins (P) disposed in the circumferential direction (X) at a lower end of the jig (<NUM>) and on a single vertical pin (Py) disposed at the center of a lower surface of the jig (<NUM>).