JP2017070406A - Stent - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stent configured to easily reduce the diameter thereof, being easily collected from a body, and providing a uniform expansive force.SOLUTION: A stent 10 includes: a plurality of axial lines 30 continuing from an axial-direction one end side to the other end side and extending in parallel to each other; and a plurality of struts 40 that are disposed at prescribed intervals apart along a direction extending between the axial lines 30 and 30 and connect the axial lines 30 and 30. Each strut 40 has a shape bent into a chevron shape, a crown part 41 thereof is disposed facing the axial-direction other end side of the stent. The respective struts 40 disposed between the axial line 30 and an axial line 30 located adjacent to one side in the circumferential direction are connected to the axial lines 30 and 30 in such a manner as to be deviated in the extension direction of the axial line 30 with respect to respective struts 40 disposed between the axial line 30 and an axial line 30 adjacent to the other side in circumferential direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to stents placed in tubular organs such as bile ducts, ureters, trachea, blood vessels, body cavities, and other body tissues.

  For a long time, a stent has been placed in a stenosis or occlusion that has occurred in the body of a tubular organ or body cavity such as a bile duct, ureter, trachea, blood vessel, or esophagus to expand the stenosis or occlusion. Treatment using a stent has been performed, such as facilitating the flow of blood, blood, or the like, or placing a stent at a site where an aneurysm has occurred to prevent its rupture. As these stents, for example, those formed by braiding metal wires and forming into a cylindrical shape, or those formed by processing a metal cylinder by laser cutting or the like into a mesh cylinder are used.

  By the way, when a stent is placed in a tubular organ such as a bile duct, the lumen of the stent may be obstructed with the passage of time due to body fluid such as bile or proliferation of cancer cells. May need to be recovered. In this case, for example, one end of the stent placed in the tubular organ is grasped with forceps, a snare or the like, and then pulled to peel the stent from the inner wall of the tubular organ, and then pulled further to pull the tubular organ. The stent is extracted from the inside.

  By the way, a stent formed by laser cutting a metal cylinder has the advantage that it is difficult to shorten (the axial length is difficult to change) and can be placed in a predetermined position of the tubular organ with high accuracy. It is difficult to recover by biting into As a stent having such a laser cut structure, Patent Document 1 below has a plurality of segment segments in which a plurality of segment struts are formed by being bent in a zigzag pattern via a mountain-shaped or valley-shaped transition portion. In addition, a stent is described in which adjacent annular segments are connected in an axial direction via a plurality of connector struts.

  Moreover, the segment support | pillar arrange | positioned between the connector support | pillars adjacent to the circumferential direction makes | forms the shape bent in the mountain shape, and the top part is arrange | positioned facing the same direction. And the connector support | pillar has connected the mountain-shaped top part of the segment support | pillar, and the several segment support | pillar bends zigzag and forms one cyclic | annular segment. For this reason, a portion in which a plurality of mountain-shaped segment struts are arranged along the circumferential direction of the stent (dense portion) and a portion in which the mountain-shaped segment struts are not arranged (sparse portion) are the stent axis. The structure is arranged alternately along the direction (see FIG. 1). When the eyelet-shaped head end of one end of the stent is gripped and pulled with forceps or the like, the mountain-shaped segment strut is closed and the stent is reduced in diameter so that the stent can be pulled out.

Special table 2007-529245 gazette

  However, in the stent of Patent Document 1, there are a portion where the mountain-shaped segment struts are densely arranged and a portion where the mountain-shaped segment struts are sparse. Therefore, when the stent is pulled to be recovered from the body, the mountain-shaped segment struts In the densely arranged portion, the mountain-shaped segment struts are difficult to close, making it difficult to reduce the diameter of the stent and possibly making it difficult to collect the stent. In addition, after the stent is reduced in diameter, it is accommodated in a medical tube such as a catheter or a sheath, moved to a predetermined position, and then expanded and placed. Since there are a densely arranged portion and a sparse portion, it is difficult to obtain a uniform expansion force, and there is a possibility that it is difficult to uniformly expand the body tissue.

  Accordingly, an object of the present invention is to make it easier to reduce the diameter of a stent so that it can be easily recovered from the body, corrected in position, etc., and uniformly expanded when expanded from a reduced diameter state. It is to provide a stent capable of obtaining force.

  In order to achieve the above object, the present invention is a stent comprising a metal tube formed in a mesh shape, and is continuous from one end side to the other end side in the axial direction of the stent and extends in parallel. Each strut having a plurality of axial portions and a plurality of strut portions arranged between the adjacent axial portions at a predetermined interval along a direction in which the axial portions extend, and connecting the adjacent axial portions. The portions are bent into chevron shapes, and the apex portions of the chevron portions are arranged so as to face the other end side in the axial direction of the stent, respectively, and the axial portion and one of the circumferential portions with respect to the axial portion Of the strut portions disposed between the axial portions adjacent to each other, at least the other end portions in the circumferential direction with respect to the axial portion except for those located at both ends in the axial direction of the stent. Between the axis part adjacent to Among the arranged strut portions, those other than those located at least at both ends in the axial direction of the stent are connected to the axial portion while being displaced in the extending direction of the axial portion. .

  In the stent of the present invention, each strut portion disposed between the axial portion and the axial portion adjacent to the axial portion on one side in the circumferential direction, and the axial portion and the axial portion. Each strut portion arranged between the axial portion adjacent to the other side in the circumferential direction is directed toward the direction in which the axial portion extends except at least those located at both ends in the axial direction of the stent. It is preferable that they are alternately arranged in a staggered pattern.

  In the stent of this invention, it is preferable that the said axial part is provided so that a spiral shape may be made | formed with respect to the axial direction of the said stent.

  In the stent of the present invention, the adjacent axial portions are bent so that a portion where the interval is widened and a portion where the interval is narrowed are alternately repeated in the extending direction of the axial portion. Preferably it is formed.

  In the stent according to the present invention, it is preferable that the strut portion is disposed inside a portion of the adjacent axis portions where the distance between the strut portions increases.

  In the stent according to the present invention, there is an S-shaped bent portion having a shape bent in an S shape between a portion where the interval between the adjacent axial portions widens and a portion where the interval decreases. It is preferable that both end portions of the strut portions are respectively connected to the S-shaped bent portions of the adjacent axial portions.

  According to the present invention, the axial portion is continuous from one end side to the other end side in the axial direction of the stent and extends in parallel, and the top of each strut portion that connects adjacent axial portions is formed. Is provided so as to face the other end side in the axial direction of the stent. When the stent is pulled toward one end side (hand side) in the axial direction, the axial portion is pulled and the strut portion having a mountain shape is Because it is pulled in the opposite direction, the top of the strut part can be made difficult to get caught in the body tissue, and the stent can be recovered from the body, the indwelling position can be finely corrected, and re-stored in the medical tube. Can do.

  In addition, among each strut portion disposed between a predetermined axial portion and an axial portion adjacent to one side in the circumferential direction with respect to the axial portion, except for those located at least at both ends in the axial direction of the stent, Among the strut portions arranged between the axial portion and the axial portion adjacent to the other side in the circumferential direction with respect to the axial portion, at least lines other than those located at both ends in the axial direction of the stent Since the position is displaced in the direction in which the portion extends and is connected to the axial portion, the strut portion can be arranged more evenly, the diameter of the stent can be easily reduced, and the stent can be placed at a predetermined position in the body tissue. When the diameter of the stent is expanded from the reduced state to be indwelled, the stent can be expanded with a uniform expansion force, and the stent can be securely indwelled at a predetermined position in the body tissue.

1 shows a first embodiment of a stent according to the present invention, wherein (a) is a perspective view of a stent main body constituting the stent, and (b) is a perspective view when a cover is covered on the stent main body. It is sectional drawing of the stent. It is an expanded view of the stent main body which comprises the stent. It is explanatory drawing which shows the state which detained the stent in the body. It is an enlarged explanatory view showing a state when the stent is pulled out from the body. The 2nd Embodiment of the stent which concerns on this invention is shown, (a) is a perspective view of the stent main body which comprises a stent, (b) is a perspective view when a cover is coat | covered by the stent main body. It is an expanded view of the stent main body which comprises the stent. 3rd Embodiment of the stent which concerns on this invention is shown, and it is the expanded view. It is explanatory drawing of the state which pulled the stent. The 4th Embodiment of the stent which concerns on this invention is shown, and it is the expanded view. The 5th Embodiment of the stent which concerns on this invention is shown, and it is the principal part enlarged view.

  Hereinafter, with reference to FIGS. 1-5, 1st Embodiment of the stent which concerns on this invention is described.

  As shown in FIG. 1A, the stent 10 of this embodiment includes a stent body 20 having a substantially cylindrical shape in which a plurality of mesh-shaped openings 25 are provided and both axial ends 21 and 23 are opened. Have. As shown in FIGS. 1B and 2, the stent 10 has a structure in which an inner cover 50 is covered on the inside of the stent body 20 and an outer cover 60 is covered on the outside of the stent body 20. This is a so-called covered stent. In addition, it is good also as a stent which does not coat | cover the inner cover 50 and the outer cover 60, and it is good also as a stent which covered only one of the inner cover 50 or the outer cover 60. FIG.

  Both end portions 21 and 23 in the axial direction of the stent body 20 have a trumpet shape that gradually increases in diameter toward the outside in the axial direction, and the engagement force with respect to the inner periphery of a body tissue such as a tubular organ is enhanced. . In addition, only the one end part 21 and the other end part 23 of the stent main body 20 may be diameter-expanded, and it is good also as straight shape, without expanding the both-ends parts 21 and 23. FIG. Further, an enlarged portion may be provided in the middle of the stent body 20 in the axial direction to increase the engagement force with respect to the inner periphery of the body tissue.

  In the following description, the end side of the stent body 20 where the one end 21 is provided is defined as one end side of the stent 10 in the axial direction, and the end side of the stent body 20 where the other end 23 is provided. The other end side of the stent 10 in the axial direction.

  The stent 10 is made of a metal tube formed in a mesh shape. For example, a metal cylinder is processed by laser processing, etching, or the like to form a plurality of axis portions 30 or strut portions 40, which will be described later, to provide the stent body 20 or to a metal plate by laser processing or the like. The stent body 20 may be provided by forming the axial part 30 and the strut part 40 in advance and bending the metal plate into a cylindrical shape. That is, the “metal cylinder formed into a mesh shape” in the present invention includes a shape formed by bending a processed metal plate into a cylindrical shape.

  The stent body 20 is a self-expanding type that is normally expanded in diameter. However, the stent body 20 is mounted on the outer periphery of the balloon catheter, and the balloon is expanded by expanding the balloon disposed inside the stent. It is good also as an enlarged diameter type.

  As shown in FIGS. 1 and 3, the stent body 20 includes a plurality of axial portions 30 that are continuous from one end side to the other end side in the axial direction of the stent 10 and extend in parallel, and an axial portion. 30 and 30, a plurality of strut portions 40 are arranged at predetermined intervals along the extending direction of the axial portion 30 and connect the adjacent axial portions 30 and 30.

  Referring also to the development view of FIG. 3, the axial portion 30 in this embodiment is linear along the axial direction C of the stent 10 from one axial end side to the other end side of the stent 10. It extends continuously. A plurality of the axial portions 30 are arranged in parallel at a predetermined interval in the circumferential direction of the stent 10 so as to be parallel to each other. Note that the axial portion may be continuous from one end side to the other end side in the axial direction of the stent and extend in parallel. For example, the axial portion has a spiral shape or a meandering bent shape. (These will be described in other embodiments described later), and are not particularly limited.

  Moreover, it is preferable that 3-24 pieces of the axial part 30 are provided in the circumferential direction of the stent 10, and it is more preferable that 8-16 pieces are provided. Moreover, it is preferable that the space | interval of the adjacent axis part 30 (space | interval of the adjacent sides of an adjacent axis part) is 750-34000 micrometers in the expansion state without external force, and is 1000-15000 micrometers. preferable.

  As shown in FIGS. 1 and 3, each strut portion 40 that connects the adjacent axial portions 30, 30 has a shape bent into a mountain shape having a top 41. And the both end parts 43 and 43 of each strut part 40 are connected with the axial parts 30 and 30, respectively, and the adjacent axial parts 30 and 30 are connected now. Further, all the strut portions 40 are arranged so that the mountain-shaped top portions 41 face the other end side in the axial direction of the stent 10.

  The strut portion 40 in this embodiment has a substantially V shape in which the top portion 41 has an acute angle and both side portions are gradually expanded. For example, the top portion 41 is substantially rounded. It may be U-shaped, and may be any shape as long as adjacent axis portions 30 and 30 can be connected to each other and bent into a mountain shape having a top portion.

  In addition, it is preferable that the space | interval of the strut parts 40 adjacent to an axial direction (space | interval of the sides where the adjacent strut parts face each other) is 500-40000 micrometers in the expanded state without external force, and is 1500-30000 micrometers. It is more preferable.

  And in this stent 10, as shown in FIG. 3, each strut part 40 arrange | positioned between the predetermined axial part 30 and the axial part 30 adjacent to the one side of the circumferential direction with respect to this axial part 30 is shown. Among these, at least those other than those located at both ends in the axial direction of the stent 10 are disposed between the predetermined axial portion 30 and the axial portion 30 adjacent to the other side in the circumferential direction with respect to the axial portion 30. Each strut portion 40 has a structure in which it is displaced in the extending direction of the axial portion 30 and connected to the axial portion 30 with respect to those other than those located at least at both ends in the axial direction of the stent 10.

  This will be described in detail. As shown in FIG. 3, for example, when the predetermined axial portion 30 is the second axial portion 30 from the top, the circumferential direction with respect to the predetermined axial portion 30 and the axial portion 30. The strut portions 40 disposed between the axial portions 30 adjacent to one side of the first axial portion 30 (first from the top) are connected to the predetermined axial portion 30 (second from the top) and the axial portion 30. With respect to each strut part 40 arrange | positioned between the axial line parts 30 (3rd from the top) adjacent to the other side of the circumferential direction, it is comprised so that it may position-shift in the direction where the axial line part 30 is extended. That is, when a row in which a plurality of strut portions 40 are arranged between the axis portions 30 and 30 is S1, S2, S3, S4, S5, and S6 along the circumferential direction of the stent 10, for example, S2 The plurality of strut portions 40 arranged in the row are axial portions with respect to the plurality of strut portions 40 arranged in the S1 row adjacent to one side in the circumferential direction and the S3 row adjacent to the other side in the circumferential direction. 30 is displaced in the extending direction (here, the same direction as the axial direction C of the stent 10).

  In this case, in this embodiment, the connecting portion of the strut portion 40 to the axial portion 30 is connected to the middle of the connecting portion to the axial portion 30 of the strut portion 40 in the adjacent row. Also good.

  Further, in this embodiment, the end portions 43 of the strut portions 40 adjacent to each other in the circumferential direction are alternately connected to each axial portion 30 along the extending direction thereof, so that the predetermined axial portions 30, 30 are connected. The strut portions 40 disposed between the strut portions 40 and the strut portions 40 disposed between the other axial portions 30, 30 adjacent to one side or the other side in the circumferential direction with respect to the strut portions 40 It is arranged in a zigzag pattern in the extending direction.

  That is, as shown in FIG. 3, each strut portion 40 disposed between a predetermined axial portion 30 and an axial portion 30 adjacent to the axial portion 30 on one side in the circumferential direction, and the predetermined axial line. The strut portions 40 arranged between the portion 30 and the axial portion 30 adjacent to the other side in the circumferential direction with respect to the axial portion 30 except for those other than those located at least at both ends in the axial direction of the stent 10 Thus, a structure is formed in which zigzag is alternately arranged in the extending direction of the axial portion 30.

  However, as in the strut portions 40A, 40B, and 40C shown by imaginary lines in FIG. 3, it is possible to make a structure in which a plurality of strut portions 40 adjacent to each axial portion 30 in the circumferential direction are connected. .

  Further, as shown in FIG. 3, each strut portion 40 disposed between a predetermined axis portion 30 and the axis portion 30 adjacent to the one side in the circumferential direction with respect to the axis portion 30 is Struts disposed at equal intervals along the extending direction, and each strut disposed between the predetermined axial portion 30 and the axial portion 30 adjacent to the axial portion 30 on the other side in the circumferential direction. The portion 40 is located between each of the strut portions 40 disposed between the predetermined axial portion 30 and the axial portion 30 adjacent to the axial portion 30 on one side in the circumferential direction, and the axial portion It arrange | positions at equal intervals along the direction where 30 extends.

  In this embodiment, as shown in FIG. 3, struts disposed between the predetermined axial portion 30 and the axial portion 30 adjacent to one side in the circumferential direction also at both axial ends of the stent 10. The portion 40 and the strut portion 40 disposed between the predetermined axial portion 30 and the axial portion 30 adjacent to the other side in the circumferential direction are displaced in the extending direction of the axial portion 30. However, it is good also as a structure where position shift does not occur at both ends of the stent 10 in the axial direction.

  That is, as shown in FIG. 3, in this embodiment, at one end side (end portion 21 side) in the axial direction of the stent 10, S2, S4, S6 provided every other along the circumferential direction of the stent 10. Although the strut portions 40 are arranged only in the rows, the strut portions 40 may be arranged in all rows S1 to S6 as shown by the imaginary lines in FIG.

  Further, on the other end side (end portion 23 side) of the stent 10 in the axial direction, it is provided every other row along the circumferential direction of the stent 10 in which the strut portions 40 are not arranged on the one end side of the stent described above. Although the strut portions 40 are arranged only in the S1, S3, and S5 rows (see FIG. 3), the strut portions 40 may be arranged in all the rows S1 to S6 (see the imaginary line in FIG. 3). ).

  Further, as shown in FIGS. 1 and 2, a ring-shaped extraction portion 27 is provided at one axial end portion of the plurality of axial portions 30, and these extraction portions 27 have a loop shape. An extraction wire 29 is inserted, and as shown in FIGS. 2 and 5, the stent 10 can be extracted from the body by grasping and pulling the extraction wire 29 with the forceps 5 or the like. In FIG. 3, the drawing portion 27 is omitted for convenience.

  Further, in this embodiment, as shown in FIG. 3, the wire diameter (width) of the axial portion 30 is the same as the wire diameter (width) of the strut portion 40. You may form smaller than the wire diameter of the strut part 40. FIG. In this case, the rigidity of the axial part 30 becomes lower than the rigidity of the strut part 40, the axial part 30 becomes easy to bend, and it can make it hard to kink.

  The stent 10 is housed in a medical tube by reducing the diameter of the top 41 of each strut portion 40 toward the distal end side of a medical tube such as a catheter or sheath, and when the stent is a balloon expandable type Is sheathed on the outer periphery of a medical tube such as a balloon catheter with the diameter reduced in a state where the top 41 of each strut portion 40 faces the distal end side of the catheter. Then, in the above state, the medical tube is inserted into the body and moved, and the stent is opened and expanded in diameter at a predetermined position, so that the top portion 41 of each strut portion 40 faces in the insertion direction of the medical tube. In the state, the stent 10 is deployed. On the other hand, when the stent 10 is recovered from the body or the position is corrected, the stent 10 is pulled from one end side of the stent 10 to the proximal side opposite to the direction of the top portion 41 of each strut portion 40. (See FIG. 5).

  That is, “the other end side in the axial direction of the stent” is an end portion on the insertion direction side when the stent is inserted into the body, and “one end side in the axial direction of the stent” is a position when the stent is recovered from the body. It becomes the end of the pulling direction side toward the hand side.

  The material of the stent body 20 is not particularly limited. For example, stainless steel, Ta, Ti, Pt, Au, W, Ni—Ti alloy, Co—Cr alloy, Co—Cr—Ni alloy, Cu, etc. A shape memory alloy such as a Zn—X (X = Al, Fe, etc.) alloy or a Ni—Ti—X (X = Fe, Cu, V, Co, etc.) alloy is preferred.

  In addition, at a predetermined position of the stent body 20, for example, Pt, Ti, Pd, Rh, Au, W, Ag, Bi, Ta and alloys thereof, synthetic resin containing powder such as BaSO4, Bi, W, stainless steel A radiopaque X-ray marker composed of the above may be provided.

  Further, as described above, the inner cover 50 is coated on the inner side of the stent body 20, and the outer cover 60 is coated on the outer side of the stent body 20. As shown in the cross-sectional view of FIG. 2, the inner cover 50 covers the inside of the stent body 20 and is embedded up to the middle of the thickness direction, and the outer cover 60 covers the outside of the stent body 20. At the same time, it is embedded up to a portion that is not embedded in the inner cover 50, and the mesh-shaped opening 25 of the stent body 20 is blocked by both covers 50, 60.

  The inner cover 50 and the outer cover 60 are made of, for example, polyurethane, silicone, natural rubber, nylon elastomer, polyether block amide, polyethylene, polyvinyl chloride, vinyl acetate, or polytetrafluoroethylene (PTFE), par Fluoro-resin such as fluoroalkoxy resin (PFA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-ethylene copolymer (ETFE), olefin rubber such as polybutadiene, styrene It is preferably formed of an elastomer or the like.

  Next, an example of how to use the stent 10 of the present invention having the above-described configuration will be described. In addition, this usage method is an example and is not particularly limited.

  As shown in FIG. 4, a papilla 2 is provided at the lower part of the duodenum 1, and a bile duct 3 and a pancreatic duct 4 branch and extend from the papilla 2. In addition, bile produced by a liver (not shown) flows through the bile duct 3, passes through the teat 2, and is supplied to the duodenum 1. Here, a procedure for placing the stent 10 in the bile duct 3 through the nipple 2 will be described.

  In addition to the bile duct 3, the stent 10 of the present invention can be placed in the pancreatic duct 4, the duodenum 1, tubular organs such as the esophagus, trachea, large intestine, and blood vessels, body cavities, and other body tissues. Is not particularly limited.

  First, the diameter of the stent 10 is reduced and stored in a medical tube (not shown) such as a catheter or a sheath. At this time, the other end side in the axial direction of the stent 10 is directed toward the insertion direction of the medical tube or the stent 10 into the body, that is, the top 41 of each strut portion 40 is directed toward the distal end side of the medical tube. Then, the diameter of the stent 10 is reduced and accommodated in the medical tube.

  In this state, after inserting a guide wire into the bile duct 3 through a lumen of an endoscope (not shown) by a well-known method, a medical tube is inserted through the guide wire, so that the stent 10 can be moved in the axial direction or the like. Insert into the bile duct 3 from the end side. And if the front-end | tip part of a medical tube reaches | attains the predetermined position of the bile duct 3, a medical tube will be stopped. Thereafter, the stent 10 is released from the distal end of the tube via a pusher or the like to expand the diameter of the stent 10 and, as shown in FIG. 4, the other end of the stent is disposed in the bile duct 3 and the one end of the stent is The stent 10 is placed by placing it slightly protruding from the nipple 2. At this time, in the stent 10, the top portion 41 of each strut portion 40 faces in the insertion direction of the medical tube or the stent 10, and each strut portion 40 of the expanded stent 10 engages with the inner circumference of the bile duct 3. As a result, the bile duct 3 is placed at a predetermined position (see FIGS. 4 and 5).

  And in this stent 10, as shown in FIG. 3, each strut part 40 arrange | positioned between the predetermined axial part 30 and the axial part 30 adjacent to the one side of the circumferential direction with respect to this axial part 30 is shown. Among these, at least those other than those located at both ends in the axial direction of the stent 10 are disposed between the predetermined axial portion 30 and the axial portion 30 adjacent to the other side in the circumferential direction with respect to the axial portion 30. Since each strut portion 40 has a structure that is displaced in the extending direction of the axial portion 30 and connected to the axial portion 30 with respect to those other than those located at least at both ends in the axial direction of the stent 10, As described above, when the diameter of the stent 10 is expanded from the reduced state so as to place the stent 10 at a predetermined position in the body tissue, the diameter of the stent 10 can be expanded with a uniform expansion force. Yo It can be expanded uniformly Te.

  Moreover, in this embodiment, as shown in FIG. 3, each strut part 40 arrange | positioned between the predetermined axial part 30 and the axial part 30 adjacent to the one side of the circumferential direction with respect to this axial part 30. As shown in FIG. And each strut portion 40 disposed between the predetermined axial portion 30 and the axial portion 30 adjacent to the other side in the circumferential direction with respect to the axial portion 30 is at least at both ends in the axial direction of the stent 10. Since it is arranged in a zigzag pattern alternately in the extending direction of the axial line portion 30 except for those that are positioned, as described above, the stent is contracted to be placed at a predetermined position in the body tissue. When the diameter is expanded from the diameter, the stent 10 can be expanded with a more uniform expansion force.

  As described above, when the stent 10 is placed in the bile duct 3, the stent 10 maintains the expanded diameter of the bile duct 3. However, the stent 10 may be expanded due to body fluid such as bile or cancer cell proliferation. When the 10 lumens are occluded or the treatment is completed, the stent 10 may be desired to be recovered from the body. In addition, during the placement operation of the stent 10, there may be a case where it is desired to finely adjust the position of the stent 10, and when the placement position of the stent 10 is greatly deviated, the stent 10 is temporarily re-stored in the medical tube. , You may want to correct that position.

  In such a case, as shown in FIG. 2, for example, a forceps 5 is inserted into the duodenum 1 through a lumen of an endoscope (not shown), and the forceps 5 is used to form a loop disposed on one end of the stent. Then, as shown in FIG. 5, the forceps 5 is pulled toward the operator's hand side. As a means for pulling the stent, for example, a loop-shaped snare may be hooked on one end of the stent and the stent may be pulled via the snare, and there is no particular limitation.

  The stent 10 has an axial portion 30 that is continuous from one axial end side to the other end side of the stent 10 and extends in parallel, and each strut portion that connects the axial portions 30 and 30 to each other. Since the top 41 of 40 is provided so as to face the other end side of the stent 10 in the axial direction, when the stent 10 is pulled toward the proximal side as described above, as shown in FIG. Is pulled, and each strut portion 40 having a mountain shape is pulled in the direction opposite to the direction of the top portion 41 through the axial portion 30, the strut portion 40 on one end side of the stent is closed, and the stent 10 is reduced in diameter. As a result, the strut portion 40 and the inner periphery of the bile duct 3 are released while being pulled.

  As a result, the top portion 41 of each strut portion 40 can be prevented from being caught in the body tissue (here, the inner circumference of the bile duct 3), so that the recovery from the body tissue of the stent 10 and the fine adjustment of the position of the stent 10 Can smoothly re-store the stent 10 in the medical tube. If the top portion 41 of the strut portion 40 is placed in a state facing the stent pulling side, the top portion 41 is likely to bite into the body tissue when the stent is pulled, and the stent 10 is difficult to pull. In the case of this embodiment, the stent 10 extracted from the bile duct 3 can be recovered from the body through a lumen of an endoscope (not shown).

  Further, when the stent 10 is pulled as described above, the strut portion 40 is closed and the stent 10 is pulled while being reduced in diameter. The mountain-shaped segments are not arranged densely in the stent circumferential direction, but are arranged between a predetermined axial portion 30 and the axial portion 30 adjacent to the axial portion 30 on one side in the circumferential direction. Each strut portion 40 and each strut portion 4 disposed between the predetermined axis portion 30 and the axis portion 30 adjacent to the other side in the circumferential direction with respect to the axis portion 30 extend the axis portion 30. Since it is displaced in the direction and connected to the axial portion 30, the strut portion 40 can be evenly arranged, the diameter of the stent 10 can be easily reduced, and the stent 10 can be pulled smoothly. Door can be.

  Further, since the stent 10 is made of a metal tube formed in a mesh shape, the stent 10 has a property that there is little shortening when the diameter of the stent 10 is reduced and when the diameter is increased, and the indwelling position is not easily displaced. Yes. In addition, since the axial portion 30 continuously extends from one end of the stent toward the other end, and the adjacent axial portions 30 and 30 are connected by the strut portion 40, the stent 10 is contracted. At the time of diameter expansion and diameter expansion, the axial portion 30 does not expand and contract, and each strut portion 40 opens and closes like a pantograph with the top portion 41 as a boundary, so that the stent 10 is contracted or expanded. Therefore, the shortening of the stent 10 can be further reduced, and the stent 10 can be accurately placed at a desired position in the body tissue.

  Furthermore, since it has the some axial part 30 continuously extended in parallel toward the other end side from the one end side of the stent, as described above, the stent 10 is used at the time of stent recovery or position correction. Even when it is pulled, it is difficult to deform the entire structure of the stent 10 and shape retention performance can be improved. In the case where the stent has a structure in which a wire is braided or a structure that does not have an axial portion, the stent structure is likely to be deformed when the stent is pulled.

  6 and 7 show a second embodiment of the stent according to the present invention. Note that substantially the same parts as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the stent 10A of this embodiment, the arrangement of the axial line portion is different from that of the above embodiment. 6 and 7 together, the axial portion 30A in this embodiment has a helical shape with respect to the axial direction C of the stent 10A from one end side to the other end side in the axial direction of the stent 10A. Are provided in parallel so as to be parallel to each other.

  Moreover, as shown in FIG. 7, each strut part 40 arrange | positioned between predetermined axis part 30A, 30A is on the one side or the other side of the circumferential direction except what is located in the axial direction both ends of 10 A of stents. The strut portions 40 disposed between the other adjacent axial portions 30A, 30A are connected to the axial portion 30A while being displaced in the direction in which the axial portion 30A extends (in a spiral extending direction).

  Furthermore, as shown in FIG. 7, in the development view of the linear pattern of the stent 10A, the angle θ of each axial line portion 30 with respect to the axial direction C of the stent 10A is preferably 10 to 80 °, and 20 to 70 °. It is more preferable that

  And in this embodiment, since 30 A of axial parts are provided so that a spiral shape may be made | formed with respect to the axial direction of 10 A of stents, compared with what a linear part extends linearly (1st Embodiment). The flexibility when the stent 10A is bent can be increased. For example, when the medical tube containing the stent 10A is advanced to a bent tubular organ, or when the stent 10A is placed in the bent tubular organ, the stent 10A is bent. 10A can be made difficult to kink (bend).

  8 and 9 show a third embodiment of the stent according to the present invention. Note that substantially the same parts as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The stent 10B of this embodiment is different from the above-described embodiment in that the axial line portion 30B has a meanderingly extending shape.

  That is, the adjacently disposed axial portions 30B and 30B are configured such that the portion L1 in which the interval between them is widened and the portion L2 in which the interval is narrowed are alternately repeated in the extending direction of the axial portion 30B. It is bent and formed into a meandering shape. In addition, in the axial portions 30B and 30B arranged adjacent to each other, the portion L1 where the interval between each other increases and the portion L2 where the interval between each other decreases are alternately provided in the circumferential direction of the stent (FIG. 8). reference).

  In addition, each axial line portion 30B includes a first linear portion 31 constituting a portion L1 where the interval is widened, a second linear portion 32 constituting a portion L2 where the interval is narrowed, and end portions of both linear portions 31 and 32 It is comprised from the diagonally extending part 33 which connects diagonally.

  Each strut portion 40 has both end portions 43, 43 connected to the hatched portions 33, 33 of the axis portions 30B, 30B (see FIG. 8), and the portions of the axis portions 30B, 30B that are spaced apart from each other. Each strut part 40 is each arrange | positioned inside L1 (refer FIG. 9).

  Further, as in this embodiment, the “direction in which the axial line portion extends” in the case where the axial line portion meanders is a line segment that forms at least a portion L1 in which the interval between adjacent axial line portions is widened (here. Means the direction in which the first linear portion 31) extends, and if it includes this line segment, it is included in the axial portion of the present embodiment, for example, the axial portion meanders in a zigzag shape. Those having a line segment extending in the circumferential direction are also included. In this embodiment, the extending directions of the first linear portion 31 that forms the portion L1 where the interval is widened and the second linear portion 32 that forms the portion L2 that narrows the interval are the same. Yes.

  In this embodiment, in the adjacent axial portions 30B and 30B, the portion L1 in which the distance between each other is increased and the portion L2 in which the distance between each other is reduced are alternately repeated in the extending direction of the axis portion 30B. Therefore, it is possible to ensure a long extension of the axial portion 30B, to secure a large contact area with the body tissue, and to place it firmly at a predetermined position. In addition, since the axial portion 30B has not only an axial component but also a circumferential component, it is possible to increase the retention force when the stent 10B is expanded to expand the body tissue (the bile duct 3 or the like). it can.

  Furthermore, in this embodiment, as shown in FIG. 9, when the diameter of the stent 10B is reduced, the strut portion 40 is disposed inside the portion L1 of the adjacent axial portions 30B and 30B where the interval between them increases. Therefore, the stent 10B can be more easily reduced in diameter.

  FIG. 10 shows a fourth embodiment of the stent according to the present invention. Note that substantially the same parts as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

  Similar to the second embodiment, the stent 10C of this embodiment has a plurality of axial portions 30C continuously extending so as to form a spiral shape with respect to the axial direction C of the stent 10C, and the third embodiment. Similarly to the embodiment, the adjacent axis portions 30C, 30C are alternately repeated such that the portion L1 in which the distance between each other increases and the portion L2 in which the distance between each other becomes narrower in the direction in which the axis portion 30C extends. It is bent to form a meandering shape.

  Further, in this embodiment, as in the third embodiment, the “extending direction of the axial portion” when the axial portion is meandering means at least a portion where the interval between adjacent axial portions is widened. The line segment to be formed means the extending direction. Further, FIG. 10 shows a developed view of the stent 10C. When the stent 10C has a cylindrical shape, a portion L1 between the axial portions 30C and 30C arranged adjacent to each other and the interval L1 is increased. In addition, the structure is such that the portions L2 where the distance between each other is narrowed are alternately provided in a direction orthogonal to the direction in which the axial portion 30C extends.

  In this embodiment, the same operational effects as those of the second embodiment and the third embodiment can be obtained.

  FIG. 11 shows a fifth embodiment of the stent according to the present invention. Note that substantially the same parts as those of the above-described embodiment are denoted by the same reference numerals, and description thereof is omitted.

  In the stent 10D of this embodiment, as in the third embodiment, the adjacent axis portions 30D and 30D have a portion L1 in which the interval between them is widened, and a portion L2 in which the interval is narrowed so that the axis portion 30D extends. It is bent in such a manner as to be alternately repeated in the direction and formed in a meandering shape. In addition, as in the third embodiment, the portion L1 where the interval between the axial portions 30B and 30B arranged adjacent to each other widens and the portion L2 where the interval between each other narrows are narrowed with respect to the circumferential direction of the stent. It is provided alternately. Further, the meaning of the “direction in which the axial line portion extends” when the axial line portion is meandering is the same as in the third embodiment.

  Furthermore, between each 1st linear part 31 which comprises the part L1 from which each space | interval part 30D spreads, and the 2nd linear part 32 which comprises the part L2 from which a mutual space | interval narrows, it is S-shaped. S-shaped bent portions 35 each having a bent shape are provided. And the both ends 43 and 43 of each strut part 40 have comprised the structure connected with the S-shaped bending parts 35 and 35 of adjacent axial part 30D and 30D, respectively.

  And in this embodiment, since the both ends 43 and 43 of the strut part 40 are each connected with the S-shaped bending parts 35 and 35 of the axis parts 30D and 30D which are comparatively flexible and easy to bend, The stent 10D can be easily bent and can be made difficult to kink.

  It should be noted that the present invention is not limited to the above-described embodiment, and various modified embodiments are possible within the scope of the present invention, and such an embodiment is also included in the scope of the present invention. .

10, 10A, 10B, 10C, 10D Stent 20 Stent body 21 One end portion 23 Other end portion 30, 30A, 30B, 30C, 30D Axis portion 35 S-shaped bent portion 40 Strut portion 41 Top portion 43 End portion 50 Inner cover 60 Outside cover

Claims (6)

A stent composed of a metal cylinder formed in a mesh shape,
A plurality of axial portions extending in parallel from one end side in the axial direction of the stent to the other end side; and
A plurality of strut portions arranged between the adjacent axial portions at predetermined intervals along the extending direction of the axial portions and connecting the adjacent axial portions;
Each of the strut portions has a shape bent in a mountain shape, and the peak portion of the mountain shape is arranged so as to face the other end side in the axial direction of the stent,
Of the strut portions arranged between the axial portion and the axial portion adjacent to the axial portion adjacent to the axial portion, except for those located at least at both ends in the axial direction of the stent, Among the strut portions arranged between the axial portion and the axial portion adjacent to the other side in the circumferential direction with respect to the axial portion, at least for those located at both ends in the axial direction of the stent, A stent characterized in that it is displaced in the direction in which the axial portion extends and is connected to the axial portion.   Each strut portion disposed between the axial portion and the axial portion adjacent to one side in the circumferential direction with respect to the axial portion, and adjacent to the axial portion and the other side in the circumferential direction with respect to the axial portion The strut portions disposed between the axial portions are alternately staggered in the direction in which the axial portions extend except at least those located at both ends in the axial direction of the stent. The stent according to claim 1, arranged as described above.   The stent according to claim 1 or 2, wherein the axial portion is provided so as to form a spiral shape with respect to an axial direction of the stent.   The adjacent axis portions are formed by bending so that a portion where the interval is widened and a portion where the interval is narrowed are alternately repeated in the extending direction of the axis portion. The stent according to any one of -3.   The stent according to claim 5, wherein the strut portion is disposed inside a portion where the interval between the adjacent axial portions increases.   An S-shaped bent portion having an S-shaped bent shape is provided between a portion where the interval between the adjacent axial portions is widened and a portion where the interval is narrowed. The stent according to claim 4 or 5, wherein both end portions of the portion are respectively connected to the S-shaped bent portion of the adjacent axial portion.