Search

US-12622793-B2 - Synthetic resin stent and stent delivery system

US12622793B2US 12622793 B2US12622793 B2US 12622793B2US-12622793-B2

Abstract

A synthetic resin stent is able to demonstrate self-extensibility, restorability, adhesion to the digestive tract, and ability to follow peristaltic movement. The synthetic resin stent is provided with: a first stent that has a first stent body formed as a cylindrical mesh from fibers made of synthetic resin, and that can be deformed from a reduced-diameter state to an expanded-diameter state; and a second stent that is formed as a cylindrical mesh which is finer than that of the first stent body, is arranged so as to cover the outer periphery of the first stent body, and can be deformed from a reduced-diameter state to an expanded-diameter state.

Inventors

  • Junichi Ide
  • Shuji FUKUTAKI
  • Manami NISHIHARA

Assignees

  • JMS CO., LTD.

Dates

Publication Date
20260512
Application Date
20200330
Priority Date
20190328

Claims (17)

  1. 1 . A synthetic resin stent, comprising: a first stent including a first stent body formed of synthetic resin fiber into a tubular structure having a mesh, the first stent being deformable from a reduced diameter state to an expanded diameter state; and a second stent formed into a tubular structure having a mesh denser than the mesh of the first stent body, the second stent arranged so as to cover an outer periphery of the first stent body, and being deformable from the reduced diameter state to the expanded diameter state, wherein the first stent body is formed by connecting a plurality of polygonal annular portions side by side in a longitudinal direction of the first stent, in a state in which the plurality of polygonal annular portions formed of synthetic resin fiber into a polygonal annular shape as viewed in the longitudinal direction are bent or curved so as to be convex in the longitudinal direction, the plurality of polygonal annular portions each include a pair of bent portions that are bent so as to be convex toward one side in the longitudinal direction, and a pair of bent portions that are bent so as to be convex toward one other side in the longitudinal direction, the plurality of polygonal annular portions are configured by connecting the plurality of polygonal annular portions side by side in the longitudinal direction in such a manner that, in a state in which bent portions of adjacent polygonal annular portions are arranged to face each other, the bent portions of the adjacent polygonal annular portions that face each other are connected by a corresponding one of tubular connecting portions, and a pair of the adjacent polygonal annular portions is connected with each other such that mutual convex portions made of synthetic resin fiber of the pair of the adjacent polygonal annular portions is connected with each other with a corresponding one of the tubular connecting portions that connect the bent portions that are bent so as to be convex toward one side in the longitudinal direction and the bent portions that are bent so as to be convex toward one other side in the longitudinal direction.
  2. 2 . The synthetic resin stent according to claim 1 , wherein the first stent further includes an end enlarged diameter portion connected to at least one end of the first stent body in the longitudinal direction, the end enlarged diameter portion being larger in diameter than the first stent body.
  3. 3 . The synthetic resin stent according to claim 2 , wherein the end enlarged diameter portion is formed of synthetic resin fiber, the synthetic resin fiber of the end enlarged diameter portion has a diameter smaller than the synthetic resin fiber of the plurality of polygonal annular portions of the first stent body, the end enlarged diameter portion is configured into a polygonal annular structure, wherein the polygonal annular structure of the end enlarged diameter portion has more peaks and valleys than the plurality of polygonal annular portions of the first stent body.
  4. 4 . The synthetic resin stent according to claim 1 , wherein the first stent is a stent including an end flare portion arranged at an end in an axial direction, the first stent being formed of wires, a plurality of peaks composed of tip corners protruding outward in the axial direction are consecutively arranged in a circumferential direction, whereby the end flare portion is formed into an annular shape as viewed in the axial direction, an angle formed by two sides of each of the peaks is 80° or less in a state in which the stent is placed inside the gastrointestinal tract, and the number of the plurality of peaks is three to eleven.
  5. 5 . The synthetic resin stent according to claim 4 , wherein the two sides composing each of the peaks are composed of two sides of an end grid arranged at an end in the axial direction.
  6. 6 . The synthetic resin stent according to claim 5 , wherein the first stent includes a plurality of grids arranged side by side in the axial direction, and the end grid is arranged at an end of the plurality of grids.
  7. 7 . The synthetic resin stent according to claim 4 , wherein one side length of one of the two sides composing each of the peaks is 16 mm to 22 mm.
  8. 8 . The synthetic resin stent according to claim 4 , wherein adjacent ones of the peaks of the end flare portion are fixed at an intersection to the most end-side in the axial direction.
  9. 9 . The synthetic resin stent according to claim 1 , wherein the second stent is a synthetic resin stent including a first woven component portion being tubular and composed of a plurality of fibers woven into a mesh, and a second woven component portion composed of a plurality of fibers arranged so as to be woven into the first woven component portion and configured into an annular shape, the first woven component portion includes a plurality of first fibers extending so as to be inclined at a predetermined angle with respect to the axial direction, a plurality of second fibers extending so as to intersect with the first fibers, and a plurality of first intersecting points configured with intersections of the plurality of first fibers and the plurality of second fibers, the second woven component portion includes a plurality of wave-shaped third fibers arranged so as to be spaced apart in the axial direction, and a plurality of wave-shaped fourth fibers arranged so as to be spaced apart in the axial direction, and at least one first intersecting point of the plurality of first intersecting points is arranged in intersecting regions surrounded by the third fibers and the fourth fibers.
  10. 10 . The synthetic resin stent according to claim 9 , wherein the plurality of intersecting regions are formed side by side in the circumferential direction of the first woven component portion, and the plurality of first intersecting points are arranged side by side in the circumferential direction of the first woven component portion and arranged in the plurality of intersecting regions, respectively.
  11. 11 . The synthetic resin stent according to claim 9 , wherein in a configuration in which the first intersecting points are arranged in the intersecting regions, respectively, the third fibers are arranged in a state of being hookable by one or more of the first fibers, the second fibers and the fourth fibers, in relation to movement in a direction in which an overlapping portion of the third fibers and the fourth fibers shrinks in size, and the fourth fibers are arranged in a state of being hookable by one or more of the first fibers, the second fibers and the third fibers, in relation to movement in a direction in which the overlapping portion of the third fibers and the fourth fibers shrinks in size.
  12. 12 . The synthetic resin stent according to claim 11 , further comprising a plurality of configurations in which the first intersecting point is arranged in the intersecting region, wherein the synthetic resin stent is configured to partly include a configuration, in which the third fibers and the fourth fibers are arranged in a state of being mutually hookable, in relation to movement in a direction in which the overlapping portion of the third fibers and the fourth fibers shrinks in size, and arranged in a state of not being hookable by the first fibers and the second fibers when the third fibers and the fourth fibers move.
  13. 13 . The synthetic resin stent according to claim 9 , wherein a loop having a loop shape is formed at the top of the peaks of the wave-shaped third fibers and/or the wave-shaped fourth fibers, the loop arranged so as to surround any one or more of the first fibers, the second fibers, the third fibers and the fourth fibers.
  14. 14 . The synthetic resin stent according to claim 9 , wherein the second woven component portion is formed of synthetic resin fiber having an expansion force higher than the first woven component portion.
  15. 15 . The synthetic resin stent according to claim 1 , wherein the second stent is a synthetic resin stent including a first woven component portion being tubular and composed of one more fibers configured into a mesh, and a second woven component portion arranged so as to be woven into the first woven component portion and composed of one or more fibers configured into an annular shape, the first woven component portion includes a plurality of first fibers repeatedly bent so as to be inclined at a predetermined angle with respect to the axial direction and extending in the axial direction, a plurality of second fibers arranged to include a portion intersecting with the first fibers and repeatedly bent so as to be inclined at a predetermined angle with respect to the axial direction and extending in the axial direction, and a plurality of first intersecting regions configured with intersections of the plurality of first fibers and the plurality of second fibers, the second woven component portion includes a plurality of third fibers repeatedly bent so as to be inclined at a predetermined angle with respect to the axial direction and extending in the circumferential direction, a plurality of fourth fibers arranged to include a portion intersecting with the third fibers and repeatedly bent so as to be inclined at a predetermined angle with respect to the axial direction and extending in the axial direction, and a plurality of second intersecting regions configured with intersections of the plurality of third fibers and the plurality of fourth fibers, and the first intersecting regions and the second intersecting regions are arranged to at least partly overlap with each other.
  16. 16 . The synthetic resin stent according to claim 15 , wherein in a configuration in which the first intersecting region is arranged to overlap with the second intersecting region, the first fibers are arranged in a state of being hookable by one or more of the third fibers and the fourth fibers, in relation to movement in a direction in which an overlapping portion of the first fibers and the second fibers shrinks in size, and the second fibers are arranged in a state of being hookable by one or more of the third fibers and the fourth fibers, in relation to movement in a direction in which an overlapping portion of the first fibers and the second fibers shrinks in size.
  17. 17 . A stent delivery system comprising: the synthetic resin stent of claim 1 ; an outer tube that can interiorly load the first stent and the second stent, wherein the second stent and the first stent are arranged side by side in this order from the distal end side; and a pushing member that is arranged inside the outer tube and can extrude the second stent and the first stent in this order from the distal end side of the outer tube.

Description

TECHNICAL FIELD The present invention relates to a synthetic resin stent such as a biodegradable stent, and to a stent delivery system. BACKGROUND ART Stenotic diseases (such as tumors and inflammations) in natural tracts such as blood vessels and gastrointestinal tracts are heretofore treated by placing a stent at a stenotic site and dilating the stenotic site. Stents made of metal or synthetic resin are known, for example. Among these, when a metal stent is removed from the body, a surgical intervention is needed and imposes a significant burden on the patient. Therefore, use of a metal stent is limited to cases such as malignant tumors for which semi-permanent placement or surgical procedures are planned. Against such a background, a biodegradable stent as a synthetic resin stent has been proposed as a stent for use in cases where a metal stent cannot be used. A synthetic resin stent is inferior to a metal stent, in self-expandability, restorability, adherence to the gastrointestinal tract such as the intestinal tract, and trackability to peristaltic movement of the gastrointestinal tract; therefore, required performance may not be achieved when a synthetic resin stent is manufactured in the same shape as a metal stent. On the other hand, for example, a stent formed by connecting biodegradable resin processed into a zigzag shape and covered with a membrane is disclosed (e.g., see Patent Document 1). Patent Document 1: Japanese Unexamined Patent Application, Publication No. 2003-52834 DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, since the stent disclosed in Patent Document 1 is covered with a membrane, it is difficult to reduce the diameter of the stent. Since the stent disclosed in Patent Document 1 is formed by connecting biodegradable resin processed into a zigzag shape, it is difficult to balance the functions of the stent, the ends of which essentially require trackability or restorability in relation to peristaltic movement of the gastrointestinal tract, and the central portion of which requires pressure strength. Therefore, a synthetic resin stent capable of achieving self-expandability, restorability, adherence to the gastrointestinal tract, and trackability to peristaltic movement of the gastrointestinal tract has been desired. Accordingly, it is an object of the present invention to provide a synthetic resin stent and a stent delivery system capable of achieving self-expandability, restorability, adherence to the gastrointestinal tract, and trackability to peristaltic movement of the gastrointestinal tract. Means for Solving the Problems The present invention relates to a synthetic resin stent, including: a first stent including a first stent body formed of synthetic resin fiber into a tubular structure having a mesh, the first stent being deformable from a reduced diameter state to an expanded diameter state; and a second stent formed into a tubular structure having a mesh denser than the mesh of the first stent body, the second stent arranged so as to cover an outer periphery of the first stent body, and being deformable from the reduced diameter state to the expanded diameter state. The first stent body is preferably formed by connecting a plurality of polygonal annular portions side by side in a longitudinal direction of the first stent, in a state in which the polygonal annular portions formed of synthetic resin fiber into a polygonal annular shape as viewed in the longitudinal direction are bent or curved so as to be convex in the longitudinal direction. The first stent preferably further includes an end enlarged diameter portion connected to at least one end of the first stent body in the longitudinal direction, the end enlarged diameter portion being larger in diameter than the first stent body. The first stent body is preferably connected side by side to the first stent in the longitudinal direction, in a state in which the plurality of polygonal annular portions formed of synthetic resin fiber into a polygonal annular shape as viewed in the longitudinal direction are bent or curved so as to be convex in the longitudinal direction; and the end enlarged diameter portion formed of synthetic resin fiber having a diameter smaller than that of the first stent body is preferably configured into a polygonal annular structure being more polygonal than the polygonal annular portions. The first stent is preferably a stent including an end flare portion arranged at an end in an axial direction, the first stent being formed of wires; a plurality of peaks composed of tip corners protruding outward in the axial direction are preferably consecutively arranged in a circumferential direction, whereby the end flare portion is formed into an annular shape as viewed in the axial direction; an angle formed by two sides of each of the peaks is preferably 80° or less in a state in which the stent is placed inside the gastrointestinal tract; and the number of the plurality of pea