Stent placement system

Abstract

To provide a stent and a stent detention system which can accurately detain a stent on a detention target part.SOLUTION: A stent (1) is used to be detained in a lumen of a living body and comprises: stent parts (20A, 20B) which are formed in a cylindrical shape and can be expanded / shrunk in a radial direction being substantially orthogonal to an axial direction; and conversion means (30A, 30B) for converting a state of the stent parts from a diameter shrunk state into a diameter expanded state. The conversion means comprises: first linear members (31A, 31B) wound around a peripheral surface of the stent parts; and holding members (32A, 32B) holding the first linear members so as to prevent falling off thereof from the stent parts. By engagement of the first linear member and the holding member, the diameter shrunk state of the stent part is held, and by release of the engagement, the state is converted from the diameter shrunk state into the diameter expanded state.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention ,vinegar Regarding tent placement systems. [Background technology]

[0002] Conventionally, stents have been known that are placed in narrowed or obstructed areas in biological lumens such as blood vessels, the esophagus, the bile duct, the trachea, the ureter, etc., to expand the diameter of the lesion and maintain the patency of the biological lumen. In stent placement, for example, for a lesion occurring near the porta hepatis, the common hepatic duct branches into the right hepatic duct and the left hepatic duct (bile ducts within the liver), so it is necessary to place a stent in each of the common hepatic duct, the right hepatic duct, and the left hepatic duct.

[0003] In such cases, conventionally, multiple stents are prepared, such as a stent for the main lumen (e.g., the common hepatic duct) and a stent for each branch lumen (e.g., the right hepatic duct and the left hepatic duct), and one stent is inserted into the opening of another stent (e.g., the mesh of the skeletal part), connecting the stents by partially overlapping them (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-138851 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of Patent Document 1 and the like, a placement system is required for each stent, and the procedure for placing the stent is complicated, raising the risk of stent deformation or breakage, and obstruction of the hepatic portal tract. On the other hand, when a Y-shaped stent is used to place a stent in a branched portion of a biological lumen in a single procedure, it is difficult to control the timing of release and expansion of each stent portion placed in the main lumen and branch lumen, raising the risk of not being able to place each stent portion accurately in the target placement site. Furthermore, there is a demand for accurate placement of not only Y-shaped stents placed at branched portions of biological lumens, but also general linear stents at target placement sites.

[0006] An object of the present invention is to provide a stent and a stent placement system that can be placed at a target placement site with high accuracy. [Means for solving the problem]

[0007] One aspect of the stent placement system according to the present invention is Sheath and both It has a cylindrical shape a first stent portion and a second stent portion that are axially connected to each other; a stent portion that is radially expandable and contractible and is accommodated in the sheath in a contracted state; the outer circumferential surface of the second stent section Wrapped around held in a A first linear member of and a converting means having The first stent portion is prevented from transitioning from a reduced diameter state to an expanded diameter state while the first stent portion is housed in the sheath; The conversion means In a state where the second stent portion is released from the sheath while the first stent portion is housed in the sheath, the second stent portion is held by the first linear member held on the outer circumferential surface of the second stent portion. The diameter of the Protect Hold, Holding the first linear member With the cancellation of the second stent portion is converted from a contracted state to an expanded state. [Effects of the Invention]

[0008] According to the present invention, a stent can be placed at a target placement site with high accuracy. [Brief explanation of the drawings]

[0009] [Figure 1] 1A and 1B are diagrams showing the configuration of a stent placement system according to one embodiment. [Figure 2] FIG. 2 is a diagram showing the appearance of a biliary stent according to an embodiment. [Figure 3] 3A and 3B are diagrams showing an example of how a biliary stent is placed. [Figure 4]4A and 4B are diagrams showing an example of an engagement mode in the conversion means. [Figure 5] 5A to 5C are diagrams showing changes in state during placement of a biliary stent. [Figure 6] 6A to 6C are diagrams showing changes in state during placement of a biliary stent. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In this embodiment, as an example of the present invention, a bile duct stent 1 will be described that is placed in the common hepatic duct H1, the right hepatic duct H2, and the left hepatic duct H3 to treat the obstruction (stenosis) by radially expanding a lesion (e.g., an obstructed or narrowed portion of the hepatic hilum HP) in the hepatic hilum HP (see FIG. 3A, etc.) outward.

[0011] Fig. 1A shows a disassembled state of stent placement system 100, and Fig. 1B shows an assembled state of stent placement system 100. In Fig. 1A and Fig. 1B, the size (length, diameter, etc.) and shape of each member constituting stent placement system 100 are shown schematically to facilitate understanding of the invention.

[0012] The stent placement system 100 is used, for example, by inserting it into the forceps hole of an endoscope when placing a biliary stent 1 in the hepatic hilum HP. As shown in Fig. 1A and other figures, the stent placement system 100 includes a tubular sheath 110, an inner rod 120 disposed inside the sheath 110 and configured to be able to advance and retreat within the sheath 110 along the axial direction of the sheath 110, and a biliary stent 1 housed within the sheath 110 in a reduced-diameter state so as to be radially expandable.

[0013] The sheath 110 has, for example, a tubular sheath body 111 made of a flexible material, and a hub 112 provided on the proximal end side of the sheath body 111 (on the right side in FIG. 1A, etc.).

[0014] The inner rod 120 has, for example, a rod-shaped rod main body 121, a distal tip 123 provided at its distal end, and a holding portion 122 for holding the biliary stent 1 in a reduced diameter state provided slightly proximal to the distal tip 123. Although not shown in the figures, the rod main body 121, the holding portion 122 and the distal tip 123 are provided with, for example, a guide wire lumen for passing a guide wire, a trigger wire lumen for passing a trigger wire for expanding the bile duct stent 1 in a contracted state at the affected area, and the like, which are formed along the axial direction of the inner rod 120. The rod body 121, the holding portion 122 and the distal tip 123 are formed from various materials having appropriate hardness and flexibility, such as resin or metal, but detailed description thereof will be omitted.

[0015] Fig. 2 is a diagram showing the appearance of a biliary stent 1 according to an embodiment. Fig. 3A and Fig. 3B are diagrams showing the placed state of the biliary stent 1. Fig. 3B shows an enlarged view of the hepatic hilum HP in Fig. 3A.

[0016] The biliary stent 1 is a so-called covered stent. The biliary stent 1 has a first stent portion 10 and second stent portions 20A and 20B branching off from the first stent portion 10. As shown in Fig. 3A and other figures, the first stent portion 10 is placed in the common hepatic duct H1, and the second stent portions 20A and 20B are placed in the right hepatic duct H2 and left hepatic duct H3.

[0017] The first stent section 10 and the second stent sections 20A, 20B have a tubular shape that defines a bile flow path. In this embodiment, the second stent sections 20A, 20B have a smaller duct diameter than the first stent section 10 and are connected to one end of the first stent section 10 so as to branch into two. That is, the biliary stent 1 has an overall Y-shape. The angle of the bifurcation section 1a where the second stent sections 20A, 20B branch is set according to the shape of the hepatic portal tract HP where the biliary stent 1 is to be placed. The first stent section 10 may have a straight tubular shape or a curved shape depending on the placement site. Furthermore, the first stent section 10 may have a curved shape that follows the common hepatic duct H1 after placement.

[0018] A first framework 11 is disposed in the first stent section 10, and second frameworks 21A and 21B are disposed in the second stent sections 20A and 20B, respectively. The first skeletal portion 11 and the second skeletal portions 21A, 21B are reinforcing members for maintaining the expanded state of the first stent portion 10 and the second stent portions 20A, 20B, and are formed, for example, by spirally winding and weaving metal wires. The first skeletal portion 11 and the second skeletal portions 21A, 21B memorize the shape of their expanded state and have so-called self-expandability. That is, the first skeletal portion 11 and the second skeletal portions 21A, 21B are configured to be self-expandable in a radial direction substantially perpendicular to their respective axial directions, from a contracted state in which they contract inward to an expanded state in which they expand outward to define a cylindrical flow path.

[0019] The first skeletal portion 11 and the second skeletal portions 21A and 21B may be connected at the crotch portion 1a or may be separated. The first skeletal portion 11 and the second skeletal portions 21A, 21B may be configured by arranging a plurality of skeletons, each formed by bending a metal wire into an annular shape so that peaks and valleys are alternately formed, at predetermined intervals in the axial direction. The first skeletal portion 11 and the second skeletal portions 21A, 21B may be configured by spirally winding one or more metal wires in the axial direction while bending the wire so that peaks and valleys are alternately formed. The first skeletal portion 11 and the second skeletal portions 21A, 21B may be formed by folding the wire back in a zigzag pattern to form alternate bent portions (peaks and valleys), and by weaving the bent portions (peaks on one side (convex portions on one axial end) and valleys on the other side (convex portions on the other axial end)) into a diamond-shaped wire mesh (fence-like) so that they interlock with each other. The first skeletal portion 11 and the second skeletal portions 21A, 21B may be laser-cut skeletal portions obtained by laser processing a metal tubular member.

[0020] Examples of materials for the metal wires forming the first skeleton 11 and the second skeletons 21A and 21B include known metals or metal alloys such as stainless steel, Ni-Ti alloy (nitinol), titanium alloy, etc. Also, alloy materials having X-ray contrast properties may be used. The first skeleton 11 and the second skeletons 21A and 21B may be made of a material other than a metal material (for example, ceramic, resin, etc.).

[0021] The material, wire type (for example, circular wire such as wire, or laser-cut angular wire), wire diameter (cross-sectional area), number of circumferential folds and fold shape (number of peaks and shape of peaks), and axial wire spacing (amount of framework per unit length) of the wires forming the first skeletal portion 11 and the second skeletal portions 21A, 21B are appropriately selected based on the flexibility of the first stent portion 10 and the second stent portion 20A, 20B required for the biological lumen in which they are to be placed. Here, flexibility refers to the ease with which the first stent portion 10 and the second stent portion 20A, 20B bend, and is determined particularly by axial bending rigidity.

[0022] The first stent section 10 and the second stent sections 20A, 20B have coating sections 12 arranged along the circumferential surfaces of the first skeletal section 11 and the second skeletal sections 21A, 21B. In this embodiment, the coating section 12 is integrally formed, thereby integrating the first stent section 10 and the second stent sections 20A, 20B.

[0023] The coating portion 12 is a membrane that forms a bile flow path. The coating portion 12 may be arranged on the outer and inner peripheral surfaces of the first skeletal portion 11 and the second skeletal portions 21A and 21B so as to sandwich the first skeletal portion 11 and the second skeletal portions 21A and 21B, or may be arranged only on the outer peripheral surfaces or only on the inner peripheral surfaces of the first skeletal portion 11 and the second skeletal portions 21A and 21B.

[0024] Examples of materials that can be used to form the coating portion 12 include silicone resin, fluororesin such as PTFE (polytetrafluoroethylene), and polyester resin such as polyethylene terephthalate.

[0025] Further, on the outer peripheral surfaces of the first skeletal portion 11 and the second skeletal portions 21A, 21B, extension restricting portions 13 are arranged along the axial directions of the first skeletal portion 11 and the second skeletal portions 21A, 21B. Specifically, the elongation restricting portions 13 are formed, for example, from rectangular elongated members, and are fixed (for example, by adhesion, etc.) to the outer peripheral surfaces (for example, the inside of the coating portion 12) of the first skeletal portion 11 and the second skeletal portions 21A, 21B so as to extend over both axial end portions of the first skeletal portion 11 and the second skeletal portions 21A, 21B. The elongation restricting portions 13 disposed on the left side of the first stent portion 10 and the second stent portion 20A in Fig. 2 are formed continuously and integrally, and the elongation restricting portions 13 disposed on the right side of the first stent portion 10 and the second stent portion 20B in Fig. 2 are formed continuously and integrally.

[0026] The extension control portion 13 is formed, for example, from a biocompatible thread (e.g., polyester thread, etc.) or fabric (woven fabric or knitted fabric), and has strength that is capable of controlling the axial extension of the first skeletal portion 11 and the second skeletal portions 21A, 21B, at least to the extent that it does not impair the radial expandability of the biliary stent 1.

[0027] The extension restricting portion 13 restricts axial extension of the biliary stent 1 when it is contracted and housed in the sheath 110. Furthermore, when the biliary stent 1 is released from the sheath 110 and the first stent portion 10 and the second stent portions 20A, 20B assume an expanded diameter state, the axial shortening rate is reduced, allowing the biliary stent 1 to be placed accurately at the target placement site in the hepatic hilum HP.

[0028] The extension restricting portion 13 may also be provided, for example, on the outside of the membrane portion 12. In this case, when the biliary stent 1 is placed in the hepatic portal hilum HP, the bile duct wall comes into contact with the extension restricting portion 13, so that the extension restricting portion 13 bites into the bile duct wall, preventing the biliary stent 1 from shifting from its placement position. Note that the extension restricting portion 13 does not necessarily have to be placed.

[0029] Furthermore, a removal assisting part 14 is connected to the other end (open end) of the first stent part 10. The removal assisting part 14 is used when removing the bile duct stent 1 placed in the hepatic portal tract HP, and has, for example, a loop-shaped fastening part to which a hook (snare: retrieval member, not shown) provided at the tip of a retrieval catheter can be fastened. The wire material forming the removal assisting portion 14 may be, for example, the same as that of the first skeletal portion 11, and may be formed integrally with the first skeletal portion 11. Furthermore, a plurality of removal assisting portions 14 may be provided in the circumferential direction at the open end of the first stent portion 10.

[0030] In the biliary stent 1, conversion means 30A, 30B are arranged on the outer peripheral surface of each of the second stent sections 20A, 20B, which can convert the second stent sections 20A, 20B from a reduced diameter state to an expanded diameter state. In this embodiment, the converting means 30A, 30B are composed of first linear members 31A, 31B wound around the outer circumferential surfaces of the second stent sections 20A, 20B, and second linear members 32A, 32B engaging with the first linear members 31A, 31B, respectively. The converting means 30A, 30B are disposed on the second stent sections 20A, 20B, for example, in a state where the biliary stent 1 is mounted on the inner rod 120, but this is merely an example and is not limiting.

[0031] The first linear members 31A, 32B and the second linear members 32A, 32B are formed, for example, from a material having a predetermined strength and rigidity, and examples of the material that can be used include suture threads such as nylon fibers or fluorine fibers, thin metal wires made of nickel-titanium alloy or stainless steel, and string-like members made of resin. In order to improve the sliding properties and make it easier to pull out the second linear members 32A and 32B, it is preferable that the first linear members 31A and 31B and the second linear members 32A and 32B are made of different materials. Also, the first linear members 31A and 32B may be formed in the shape of a wide tape.

[0032] The first linear members 31A, 31B are wound around the outer peripheral surfaces of the second stent sections 20A, 20B. Specifically, the first linear members 31A, 31B are wound in such a manner that they cannot maintain a wound state by themselves, and are held in place by engaging with the second linear members 32A, 32B. That is, in this embodiment, the second linear members 32A, 32B function as holding members that hold the first linear members 31A, 31B in place so that they cannot fall off the second stent sections 20A, 20B.

[0033] One end of each of the first linear members 31A and 31B is drawn out from, for example, a branch port 112a provided in a hub 112 (see FIG. 1A, etc.). For example, one end of the second linear members 32A and 32B is pulled out together from an opening provided separately from the branch opening 112a (not shown), and can be pulled out while making fine adjustments by turning a dial, etc. Note that the second linear members 32A and 32B may be configured to be able to be pulled out individually.

[0034] 4A and 4B are diagrams showing an example of an engagement mode of the converting means 30A, 30B. Note that, in order to make the engagement mode easier to understand, Fig. 4A and other figures show a case in which the first linear members 31A, 31B and the second linear members 32A, 32B are arranged on the outer peripheral surfaces of the second stent sections 20A, 20B in an expanded diameter state, but in reality, the first linear members 31A, 31B are wound and an appropriate tension is applied thereto, so that the second stent sections 20A, 20B are bound and in a reduced diameter state.

[0035] 4A and other figures, the first linear members 31A and 31B are wound circumferentially around the outer peripheral surfaces of the second stent sections 20A and 20B, bending and winding in the opposite direction for each rotation, while the second linear members 32A and 32B are arranged along the axial direction of the second stent sections 20A and 20B and engage with bent portions B formed on the first linear members 31A and 31B. That is, the first linear members 31A and 31B are maintained in a wound state by being engaged with the second linear members 32A and 32B. Therefore, when the engagement between the first linear members 31A and 31B and the second linear members 32A and 32B is released, the first linear members 31A and 31B naturally fall off the second stent sections 20A and 20B.

[0036] 4A, first linear members 31A and 31B have bent portions B formed side by side in the axial direction. Second linear members 32A and 32B are inserted through the bent portions B. For example, the first linear members 31A and 31B are wound around the second linear members 32A and 32B arranged along the axial direction of the second stent sections 20A and 20B while hooking the bent portions B, thereby engaging the first linear members 31A and 31B with the second linear members 32A and 32B. In this case, the second stent sections 20A and 20B are reduced in diameter by appropriately pulling both ends of the first linear members 31A and 31B to apply tension.

[0037] 4B, adjacent bent portions B formed side by side in the axial direction of first linear members 31A, 31B intersect to form annular portions R. Second linear members 32A, 32B are inserted into annular portions R. For example, second stent portions 20A, 20B are inserted into annular portion R formed by first linear members 31A, 31B, and tension is applied by pulling both ends of second linear members 32A, 32B, thereby firmly binding and determining the restrained position, and the diameters of second stent portions 20A, 20B are reduced.

[0038] 4A and the like, by pulling out the second linear members 32A, 32B, the engagement between the first linear members 31A, 31B and the second linear members 32A, 32B is easily released, and the first linear members 31A, 31B become able to detach from the second stent sections 20A, 20B. As a result, the second stent sections 20A, 20B are released from their reduced diameter state and expand in diameter due to the expansion force of the second framework sections 21A, 21B. The winding manner of the first linear members 31A and 31B shown in FIG. 4A etc. is an example, and other winding manners may also be applied.

[0039] When the biliary stent 1 is attached to the inner rod 120, it is brought into a reduced-diameter state by being extended in the axial direction and folded in the radial direction, and then housed in the sheath 110. At this time, the second stent sections 20A, 20B are held in a reduced-diameter state by the converting means 30A, 30B. One ends of the first linear members 31A, 31B and the second linear members 32A, 32B are pulled out to the outside through openings (for example, the branch opening 112a in FIG. 1A) provided in the sheath 110.

[0040] 5A to 5C and 6A to 6C are diagrams showing changes in state during placement of the biliary stent 1. Note that these drawings show the biliary stent 1 in a schematic manner, and do not show the detailed configurations of the first stent section 10 and the second stent sections 20A and 20B.

[0041] When placing the biliary stent 1 at the target placement site in the hepatic hilum HP, the sheath 110 and inner rod 120 are inserted from the mouth side along a pre-inserted guide wire (not shown), and the tip of the biliary stent 1 is positioned just before the hepatic hilum HP (see Figure 5A).

[0042] Next, the inner rod 120 and the sheath 110 are moved relative to each other, and the second stent sections 20A and 20B are gradually released from the sheath 110 until they are positioned in the right hepatic duct H2 and the left hepatic duct H3, respectively (see FIGS. 5B and 5C). At this time, the first stent section 10 remains housed in the sheath 110. In this embodiment, the outer peripheral surfaces of the second stent sections 20A and 20B are constrained by the converting means 30A and 30B, so the second stent sections 20A and 20B remain in a reduced diameter state even after being released from the sheath 110.

[0043] Next, one end of the second linear members 32A, 32B is pulled, and the second linear members 32A, 32B are gradually withdrawn (see FIG. 6A). As the second linear members 32A, 32B are withdrawn, the first linear members 31A, 31B are unwound, and the second stent sections 20A, 20B gradually expand in diameter due to the expansion force of the second framework sections 21A, 21B. The placement positions of the second stent sections 20A, 20B can be adjusted with high precision while gradually withdrawing the second linear members 32A, 32B.

[0044] Then, with the second stent portions 20A and 20B placed in the right hepatic duct H2 and the left hepatic duct H3, respectively, the first linear members 31A and 31B are withdrawn and collected (see FIG. 6B), and the sheath 110 is withdrawn to release the first stent portion 10 of the biliary stent 1 (see FIG. 6C). The first stent portion 10 expands in diameter due to the expansion force of the first skeletal portion 11, and is placed in the common hepatic duct H1. At this time, the axial shortening rate of the first stent portion 10 when it enters the expanded state is reduced by the elongation restricting portion 13, allowing the placement position of the first stent portion 10 to be adjusted with precision. In this way, the biliary stent 1 is fully expanded in diameter from the first stent portion 10 to the second stent portions 20A and 20B, and the patency of the hepatic portal hilum HP is ensured. Thereafter, although not shown, the inner rod 120 is pulled out, and the biliary stent 1 is placed in the hepatic portal hilum HP.

[0045] As described above, the bile duct stent 1 of this embodiment is a stent to be placed in the hepatic portal hilum HP (biological lumen), and is provided with second stent sections (stent sections) 20A, 20B having a cylindrical shape and capable of expanding and contracting in a radial direction substantially perpendicular to the axial direction, and conversion means 30A, 30B capable of converting the second stent sections 20A, 20B from a reduced diameter state to an expanded diameter state, and the conversion means 30A, 30B are The stent has first linear members 31A, 31B wound around the outer peripheral surface, and holding members (second linear members 32A, 32B) that hold the first linear members 31A, 31B so that they cannot fall off from the second stent sections 20A, 20B. The first linear members 31A, 31B are engaged with the holding members to maintain the reduced diameter state of the second stent sections 20A, 20B, and the engagement is released to convert the reduced diameter state to an expanded diameter state. This allows the second stent sections 20A, 20B to maintain a reduced diameter state even after being released from the sheath 110, allowing for more accurate positioning of the second stent sections 20A, 20B relative to the target placement site in the hepatic hilum HP than if they were expanded after release. Furthermore, the second stent sections 20A, 20B can be expanded in diameter simply by releasing the engagement between the first linear members 31A, 31B and the second linear members 32A, 32B, which function as holding members. This allows the biliary stent 1 to be placed accurately in the target placement site in the hepatic hilum HP.

[0046] Furthermore, the first linear members 31A, 31B are wound circumferentially around the outer peripheral surfaces of the second stent sections 20A, 20B, bending and winding in the opposite direction with each rotation, so that when the engagement with the second linear members 32A, 32B functioning as holding members is released, the first linear members 31A, 31B naturally drop off from the second stent sections 20A, 20B, and can be easily shifted to an expanded diameter state by the expansion force of the second stent sections 20A, 20B (second framework sections 21A, 21B).

[0047] In addition, the holding member is arranged along the axial direction of the second stent portions 20A, 20B and is composed of second linear members 32A, 32B that are inserted into the bending portions B formed in the first linear members 31A, 31B, and the conversion means 30A, 30B converts the second stent portions 20A, 20B, which are bound together with the second linear members 32A, 32B by the first linear members 31A, 31B and are in a reduced diameter state, into an expanded diameter state by pulling out the second linear members 32A, 32B. Specifically, multiple bent portions B are arranged in a row along the second linear members 32A, 32B, and the conversion means 30A, 30B moves at least one of the second linear members 32A, 32B and the second stent portions 20A, 20B relatively in the axial direction, thereby sequentially pulling out the second linear members 32A, 32B from the multiple bent portions B and converting the second stent portions 20A, 20B into an expanded diameter state. This allows the second stent sections 20A, 20B to be converted into the expanded diameter state by the simple operation of pulling out the second linear members 32A, 32B.

[0048] Additionally, the second linear members 32A, 32B are inserted into a ring portion R formed by the intersection of two adjacent bent portions B. This makes it easier to control the engagement positions of the first linear members 31A, 31B and the second linear members 32A, 32B, and makes it possible, for example, to uniformly bind and reduce the diameter of the second stent sections 20A, 20B in the axial direction, thereby achieving a desired reduced diameter state.

[0049] Furthermore, the biliary stent 1 has the second stent sections 20A, 20B housed in the sheath 110 in a reduced-diameter state, and the converting means 30A, 30B maintain the portions of the second stent sections 20A, 20B released from the sheath 110 in a reduced-diameter state until the engagement between the first linear members 31A, 31B and the holding members (second linear members 32A, 32B) is released. This allows the practitioner to control the timing of expanding the diameter of the second stent sections 20A, 20B, making it possible to easily position the second stent sections 20A, 20B at the target placement site, thereby achieving a stable procedure regardless of the practitioner's experience or skill.

[0050] The stent portion constituting the biliary stent 1 includes a first stent portion 10 placed in the common hepatic duct H1 (first lumen) of the hepatic hilum HP (biological lumen), and second stent portions 20A, 20B placed in the right hepatic duct H2 and left hepatic duct H3 (second lumen) branching from the common hepatic duct H1, and conversion means 30A, 30B are provided on at least the second stent portions 20A, 20B. This allows the biliary stent 1 to be easily placed in the hepatic hilum HP, which is an example of a branching portion of a biological lumen, with a single procedure.

[0051] The invention made by the inventor has been specifically described above based on an embodiment, but the present invention is not limited to the embodiment and can be modified within the scope of the gist thereof.

[0052] For example, in the embodiment, the second linear members 32A and 32B are exemplified as the holding members for holding the first linear members 31A and 31B, but this is merely an example and is not limiting, and other forms may be used. For example, the first linear members 31A and 31B may be fixed to the outer peripheral surfaces of the second stent sections 20A and 20B with an adhesive in a wound state, so that the first linear members 31A and 31B are held so as not to fall off.

[0053] In addition, although the embodiment has been described with respect to a biliary stent 1 having a Y-shape, the present invention can also be applied to stents having branched shapes other than a Y-shape, such as a T-shape or a π-shape, and the number of second stent portions may be three or more. Furthermore, the present invention can also be applied to stents having a straight cylindrical shape that does not have any branched shapes.

[0054] Furthermore, in the embodiment, when the second stent sections 20A and 20B are released from the sheath 110, the first stent section 10 is stored within the sheath 110 to maintain the reduced diameter state of the first stent section 10. However, the first stent section 10 may also be provided with a mechanism similar to the converting means 30A and 30B, so that the first stent section 10 maintains the reduced diameter state even after being released from the sheath 110 and then expands. In this case, the first stent section 10 can be released together with the second stent sections 20A and 20B, and then the biliary stent 1 can be aligned. Note that the converting means provided on the first stent section 10 may be capable of maintaining the reduced diameter state simply by tying it with a linear member without using a holding member, and may be convertible to an expanded diameter state by withdrawing the linear member.

[0055] Furthermore, in the bile duct stent 1, the first stent portion 10 and the second stent portions 20A, 20B may be fabricated separately and then connected, or the first skeletal portion 11 and the second skeletal portions 21A, 21B may be formed from the same wire material.

[0056] In addition, in the embodiment, for example, the second stent portions 20A, 20B placed in the right hepatic duct H2 and the left hepatic duct H3 may be combined with other stent portions to be extended.

[0057] The present invention is not limited to the biliary stent 1 described in the embodiment, but can be applied to stents placed in branched portions of biological lumens such as digestive lumens and blood vessels.

[0058] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0059] The disclosures of the specification, drawings and abstract contained in Japanese Patent Application No. 2019-040638, filed on March 6, 2019, are incorporated herein by reference in their entirety. [Explanation of symbols]

[0060] 1. Biliary stent (stent) 10 First stent section 20A, 20B Second stent section 30A, 30B conversion means 31A, 31B First linear member 32A, 32B Second linear member (holding member) B Bend section HP Portion of the liver (lung)

Claims

1. Sheath and a stent portion including a first stent portion and a second stent portion, both of which have a cylindrical shape and are connected in an axial direction, the stent portion being radially expandable and contractible and being accommodated in the sheath in a contracted state; a converting means having a first linear member held in a wound state around the outer peripheral surface of the second stent section, The first stent portion is prevented from transitioning from a reduced diameter state to an expanded diameter state while the first stent portion is housed in the sheath; The conversion means In a state in which the second stent portion is released from the sheath while the first stent portion is housed in the sheath, the first linear member held on the outer circumferential surface of the second stent portion holds the reduced diameter state of the second stent portion, and the second stent portion is converted from the reduced diameter state to an expanded diameter state by releasing the holding of the first linear member. Stent placement system.

2. The conversion means A holding member is provided to hold the first linear member so that it cannot fall off from the second stent portion. The stent placement system of claim 1 .

3. The second stent section includes a plurality of branch stent sections branching from an axial tip of the first stent section. The stent placement system according to claim 1 or 2.

4. The first stent portion and the second stent portion are expandable in diameter by self-expandability. The stent placement system of claim 1 .

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