Stents and stent delivery systems

Abstract

The present invention provides a stent formed by weaving wires, wherein the stent comprises: a plurality of linear intersecting parts at which linear parts intersect; and a plurality of engaging parts at which "peak" bends that bend so as to bow toward a first direction, which is one direction in the axial direction, and "trough" bends that bend so as to bow toward a second direction, which is the other direction in the axial direction, intersect. The plurality of linear intersecting parts have a first linear intersecting part and a second linear intersecting part, and the plurality of engaging parts have a first engaging part, a second engaging part, a third engaging part, and a fifth engaging part. The first engaging part and the second engaging part are disposed at different axial positions, and the second engaging part and the third engaging part are disposed at different axial positions.

Description

[Technical field]

[0001] The present invention relates to stents and stent delivery systems. [Background technology]

[0002] There is a known procedure for placing and expanding a stent for stenosis or blockage (hereinafter referred to as "stenosis, etc.") occurring in the digestive tract, etc. A stent delivery system is used to place the stent in the stenosis, etc. The stent delivery system delivers the stent to the stenosis, etc. by passing it through a treatment tool channel of an endoscope.

[0003] For example, the stent described in Patent Document 1 is formed in a form in which two V-shaped bending points are hooked together, and has high shape followability even when bent. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-265438 Summary of the Invention [Problem to be solved by the invention]

[0005] However, a stent having a highly conformable portion such as the bending points interlocking with each other as described in Patent Document 1 is difficult to accommodate in a stent delivery system because the highly conformable portion with many overlapping wires tends to be bulky. Also, in the accommodated stent, the force of radial expansion is strong in the bulky portion of the highly conformable portion, so the sliding resistance between the accommodated stent and the stent delivery system becomes large, making it difficult to release.

[0006] In view of the above circumstances, an object of the present invention is to provide a stent that has high shape conformability and is easy to accommodate and release, and a stent delivery system including the stent. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention proposes the following means. A stent according to a first aspect of the present invention is a stent formed by weaving wires, and includes a plurality of straight line intersections where straight line portions intersect, and a plurality of engagement portions where mountain-shaped bent portions that are bent toward a first direction, which is one of the axial directions, and valley-shaped bent portions that are bent toward a second direction, which is the other of the axial directions, and intersect, the plurality of straight line intersections including a first straight line intersection where a first straight line portion intersects with a second straight line portion, and a second straight line intersection where a third straight line portion intersects with a fourth straight line portion. the plurality of engaging portions include a first engaging portion where a first peak which is the mountain-shaped bent portion connected to the first direction side of the first straight portion intersects with a first valley which is the valley-shaped bent portion; a second engaging portion where a second peak which is the mountain-shaped bent portion connected to the first direction sides of the second straight portion and the fourth straight portion intersects with a second valley which is the valley-shaped bent portion; and a third engaging portion where a third peak which is the mountain-shaped bent portion connected to the first direction side of the third straight portion intersects with a third valley which is the valley-shaped bent portion. a fourth engaging portion where a fourth valley, which is the valley-shaped bent portion connected to the second direction side of the fourth straight portion, and a fourth peak, which is the mountain-shaped bent portion, intersect; a fifth engagement portion where a fifth valley, which is the valley-shaped bent portion connected to the first straight portion and the third straight portion on the second direction side, and a fifth peak, which is the mountain-shaped bent portion, intersect; A sixth valley that is the valley-shaped bent portion connected to the second direction side of the second straight portion and a sixth peak that is the mountain-shaped bent portion intersect with each other; and The first engaging portion and the second engaging portion are disposed at different positions in the axial direction, and the second engaging portion and the third engaging portion are disposed at different positions in the axial direction. The fourth hooking portion and the fifth hooking portion are arranged at different positions in the axial direction, the fifth hooking portion and the sixth hooking portion are arranged at different positions in the axial direction, the second hooking portion is arranged on the first direction side of the first hooking portion in the axial direction, and the fifth hooking portion is arranged on the first direction side of the fourth hooking portion in the axial direction.

[0008] A stent delivery system according to a second aspect of the present invention comprises an operating section, an outer tube member configured to extend distally from the operating section, an inner tube member configured to extend distally from the operating section and located inside the outer tube member, and the stent housed between the outer tube member and the inner tube member, and the operating section is configured to position the stent by moving the outer tube member or the inner tube member in the longitudinal direction. Effect of the Invention

[0009] The stent of the present invention is highly conformable and easy to receive and release. [Brief description of the drawings]

[0010] [Figure 1] 1 is a diagram showing an overall configuration of an endoscope system including a stent according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing the overall configuration of the stent. [Diagram 3] FIG. 2 is a development view of the stent deployed in the circumferential direction. [Figure 4] FIG. 4 is an enlarged view of an area F1 shown in FIGS. 2 and 3. [Diagram 5] FIG. 13 is a diagram illustrating the misalignment and pitch of the stent. [Figure 6] A cross-sectional view of the distal end of the stent delivery system. [Figure 7] FIG. 13 shows the same stent with a large displacement. [Figure 8] FIG. 13 is a development view of a modified example of the stent. [Figure 9] FIG. 4 is a development view of a stent according to a second embodiment of the present invention, which is developed in the circumferential direction. [Figure 10] FIG. 10 is an enlarged view of an area F2 shown in FIG. [Figure 11] 1 shows the results of measuring the expansive force of the stent according to the first embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] First embodiment An endoscope system 300 including a stent 100 according to a first embodiment of the present invention will be described with reference to Fig. 1 to Fig. 7. Fig. 1 is a diagram showing the overall configuration of the endoscope system 300.

[0012] [Endoscope system 300] The endoscopic system 300 includes an endoscope 200 and a stent delivery system 150 that is inserted through a channel of the endoscope 200 .

[0013] [Endoscope 200] The endoscope 200 is a known side-viewing flexible endoscope, and includes a long insertion section 210 and an operation section 220 provided at the base end of the insertion section 210. The endoscope 200 may be a direct-viewing flexible endoscope.

[0014] The insertion section 210 has a tip rigid section 211 provided at the tip, a bending section 212 that can be bent and is provided on the base end side of the tip rigid section 211, and a flexible tube section 213 provided on the base end side of the bending section 212. An imaging unit 216 having a light guide 215 and a CCD is provided on the side surface of the tip rigid section 211 in a state exposed to the outside.

[0015] The insertion section 210 is formed with a treatment tool channel 230 for inserting an endoscopic treatment tool such as a stent delivery system 150. A distal end 230a of the treatment tool channel 230 opens on a side surface of the distal end hard section 211. A proximal end of the treatment tool channel 230 extends to the operation section 220.

[0016] A lifting table 214 is provided on the distal end hard portion 211 of the treatment tool channel 230. A base end of the lifting table 214 is rotatably supported by the distal end hard portion 211. A lifting table operating wire (not shown) fixed to the distal end of the lifting table 214 extends through the insertion portion 210 to the proximal end side.

[0017] The bending portion 212 is configured to be freely bent in the up-down and left-right directions. The tip of a manipulation wire is fixed to the tip side of the bending portion 212. The manipulation wire extends through the insertion portion 210 to the manipulation portion 220.

[0018] A knob 223 for operating the operation wire and a switch 224 for operating the imaging unit 216, etc. are provided on the proximal end side of the operation section 220. The user can bend the bending section 212 in a desired direction by operating the knob 223.

[0019] A forceps port 222 communicating with the treatment tool channel 230 is provided on the distal end side of the operation section 220. A user can insert an endoscopic treatment tool such as the stent delivery system 150 from the forceps port 222. A forceps plug 225 is attached to the forceps port 222 to prevent leakage of bodily fluids.

[0020] [Stent Delivery System 150] The stent delivery system 150 is formed elongated overall, and includes a stent 100, an outer tubular member 110, an inner tubular member 120, and an operation section 140.

[0021] The outer tubular member 110 is made of resin or the like in a cylindrical shape and has flexibility. The outer tubular member 110 can be inserted through a treatment instrument channel 230 of the endoscope 200.

[0022] The inner tube member 120 has an outer diameter smaller than the inner diameter of the outer tube member 110, and can be passed through the internal space (lumen) of the outer tube member 110. The inner tube member 120 is made of resin or the like, and is flexible. A tip 130 having an outer diameter larger than the outer diameter of the outer tube member 110 is provided at the tip of the inner tube member 120.

[0023] 1, the stent 100 is accommodated in the distal end portion of a stent delivery system 150. The stent 100 is accommodated in the gap between the inner tubular member 120 and the outer tubular member 110 in a state in which the inner tubular member 120 is passed through the inside of the stent 100 and the diameter of the stent 100 is reduced.

[0024] The operation section 140 is connected to the base end sides of the outer tubular member 110 and the inner tubular member 120, and is configured to be able to move the outer tubular member 110 in the longitudinal direction relative to the inner tubular member 120. By operating the operation section 140, the operator can move the outer tubular member 110 relative to the inner tubular member 120 to expose the housed stent 100, thereby allowing the stent 100 to be placed. In addition, while the stent 100 is exposed, the operator can also move the outer tubular member 110 in the opposite direction relative to the inner tubular member 120 to re-house the stent 100.

[0025] [Stent 100] FIG. 2 is a diagram showing the overall configuration of the stent 100. As shown in FIG. The stent 100 is formed by weaving wires and has a cylindrical shape. The stent 100 is placed in a lumen of the digestive system, such as the bile duct, esophagus, duodenum, small intestine, or large intestine, and is used mainly for the purpose of expanding and maintaining the lumen.

[0026] The stent 100 of this embodiment is not a so-called covered stent, the outer circumferential surface of which is covered with a resin film or the like, but an uncovered stent, which is not covered with a film, etc. However, the stent 100 can also be used as a covered stent by covering it with a resin film or the like.

[0027] In the following description, one side of the longitudinal axis direction (axial direction) A of the stent 100 is referred to as the "first direction A1," and the other side of the longitudinal axis direction A of the stent 100 is referred to as the "second direction A2." In addition, one side of the circumferential direction C of the stent 100 is referred to as the "first circumferential direction C1," and the other side of the circumferential direction C of the stent 100 is referred to as the "second circumferential direction C2."

[0028] FIG. 3 is a development view of the stent 100 developed in the circumferential direction C. As shown in FIG. The stent 100 is formed in a cylindrical shape having a mesh pattern on its circumferential surface by wire W that extends while repeatedly bending and inclined in a circumferential direction C. The stent 100 has a plurality of linear intersections 1 and a plurality of engagement portions 2.

[0029] FIG. 4 is an enlarged view of a region F1 shown in FIGS. The linear intersection portion 1 is formed by linear intersection of linear portions 10 of the wire W. The linear portions 10 are substantially linear portions of the wire W that extend at an angle to the circumferential direction C, and also include gently curved portions.

[0030] The hooking portion (entanglement portion) 2 is formed by intersecting a mountain-shaped bent portion 3 and a valley-shaped bent portion 4. The mountain-shaped bent portion (mountain) 3 is a convex portion formed by bending the wire W, which extends at an angle in the circumferential direction C, back in the longitudinal axis direction A and becoming convex toward the first direction A1 side. The valley-shaped bent portion (valley) 4 is a convex portion formed by bending the wire W, which extends at an angle in the circumferential direction C, back in the longitudinal axis direction A and becoming convex toward the second direction A2 side (a concave portion formed in the first direction A1 side). In the hooking portion 2, the mountain-shaped bent portion 3 and the valley-shaped bent portion 4 intersect in a hook shape, so that the mountain-shaped bent portion 3 and the valley-shaped bent portion 4 are connected to each other in a manner that they cannot be separated but can move relative to each other.

[0031] 2 and 3, the first region E1 and the second region E2 are arranged alternately in the longitudinal axis direction A. The first region E1 is a region in which a plurality of linear intersections 1 are arranged in the circumferential direction C. The second region E2 is a region in which a plurality of engagement portions 2 and one linear intersection 1 are arranged in the circumferential direction C. The one linear intersection 1 arranged in the second region E2 is provided so that the wire W can move (step up, step down) in the longitudinal axis direction A.

[0032] In the following description, one straight line intersection 1 arranged in the second region E2 is also referred to as a "step shift intersection 15." As shown in Fig. 3, one step shift intersection 15 is arranged in each second region E2. The multiple step shift intersections 15 are arranged at different positions in the circumferential direction C.

[0033] The stent 100 has a plurality of second regions E2 in which a plurality of engagement portions 2 are arranged in the circumferential direction C, and therefore has high shape conformability even when bent.

[0034] [First straight line intersection 1A] As shown in Fig. 4, the first straight line portion 11 and the second straight line portion 12, which are the straight line portion 10, intersect at a "first straight line intersection portion 1A," which is a straight line intersection portion 1. Specifically, when viewed from the radial direction R of the stent 100 (see Fig. 2), the first straight line portion 11 and the second straight line portion 12 intersect at the first straight line intersection portion 1A. At the first straight line intersection portion 1A, the first straight line portion 11 passes outside the second straight line portion 12 in the radial direction R.

[0035] [Second straight intersection 1B] As shown in Fig. 4, the third straight portion 13 and the fourth straight portion 14, which are the straight portion 10, intersect at a "second straight line intersection 1B," which is a straight line intersection portion 1. Specifically, when viewed from the radial direction R of the stent 100 (see Fig. 2), the third straight portion 13 and the fourth straight portion 14 intersect at the second straight line intersection 1B. At the second straight line intersection 1B, the third straight portion 13 passes inside the fourth straight portion 14 in the radial direction R.

[0036] The first line intersection portion 1A and the second line intersection portion 1B are line intersection portions 1 adjacent to each other in the circumferential direction C. The first line intersection portion 1A and the second line intersection portion 1B are disposed in the same first region E1.

[0037] [First hanging part 21] A "first peak 31" which is a mountain-shaped bent portion 3 is continuous with the first straight portion 11 on the first direction A1 side. The first peak 31 intersects with a first valley 41 which is a valley-shaped bent portion 4 to form a "first engaging portion 21" which is an engaging portion 2.

[0038] Specifically, when viewed from the radial direction R of the stent 100, the first peak 31 and the first valley 41 intersect at a first intersection G1 and a second intersection G2. The second intersection G2 is closer to the first linear intersection 1A than the first intersection G1. At the first intersection G1, the first peak 31 passes outside the first valley 41 in the radial direction R. At the second intersection G2, the first peak 31 passes inside the first valley 41 in the radial direction R.

[0039] [Second hooking part 22] A "second peak 32" which is a mountain-shaped bent portion 3 is continuous with the second straight portion 12 and the fourth straight portion 14 on the first direction A1 side. The second peak 32 intersects with a second valley 42 which is a valley-shaped bent portion 4 to form a "second engaging portion 22" which is an engaging portion 2.

[0040] Specifically, when viewed from the radial direction R of the stent 100, the second peak 32 and the second valley 42 intersect at a third intersection G3 and a fourth intersection G4. The third intersection G3 is closer to the first linear intersection 1A than the fourth intersection G4. The fourth intersection G4 is closer to the second linear intersection 1B than the third intersection G3. At the third intersection G3, the second peak 32 passes outside the second valley 42 in the radial direction R. At the fourth intersection G4, the second peak 32 passes inside the second valley 42 in the radial direction R.

[0041] [Third hanging section 23] A "third peak 33" which is a mountain-shaped bent portion 3 is continuous with the third straight portion 13 on the first direction A1 side. The third peak 33 intersects with a third valley 43 which is a valley-shaped bent portion 4 to form a "third engaging portion 23" which is an engaging portion 2.

[0042] Specifically, when viewed from the radial direction R of the stent 100, the third peak 33 and the third valley 43 intersect at a fifth intersection G5 and a sixth intersection G6. The fifth intersection G5 is closer to the second linear intersection 1B than the sixth intersection G6. At the fifth intersection G5, the third peak 33 passes outside the third valley 43 in the radial direction R. At the sixth intersection G6, the third peak 33 passes inside the third valley 43 in the radial direction R.

[0043] [Fourth engaging part 24] A "fourth valley 44" which is a valley-shaped bent portion 4 is connected to the fourth straight portion 14 on the second direction A2 side. The fourth valley 44 intersects with the fourth peak 34 which is a mountain-shaped bent portion 3 to form a "fourth engaging portion 24" which is a engaging portion 2.

[0044] Specifically, when viewed from the radial direction R of the stent 100, the fourth peak 34 and the fourth valley 44 intersect at a seventh intersection G7 and an eighth intersection G8. The eighth intersection G8 is closer to the second linear intersection 1B than the seventh intersection G7. At the seventh intersection G7, the fourth valley 44 passes on the outside of the fourth peak 34 in the radial direction R. At the eighth intersection G8, the fourth valley 44 passes on the inside of the fourth peak 34 in the radial direction R.

[0045] [Fifth interlocking section 25] A "fifth valley 45" which is a valley-shaped bent portion 4 is connected to the first straight portion 11 and the third straight portion 13 on the second direction A2 side. The fifth valley 45 intersects with the fifth peak 35 which is a mountain-shaped bent portion 3 to form a "fifth engaging portion 25" which is an engaging portion 2.

[0046] Specifically, when viewed from the radial direction R of the stent 100, the fifth peak 35 and the fifth valley 45 intersect at a ninth intersection G9 and a tenth intersection G10. The ninth intersection G9 is closer to the second linear intersection 1B than the tenth intersection G10. The tenth intersection G10 is closer to the first linear intersection 1A than the ninth intersection G9. At the ninth intersection G9, the fifth valley 45 passes outside the fifth peak 35 in the radial direction R. At the tenth intersection G10, the fifth valley 45 passes inside the fifth peak 35 in the radial direction R.

[0047] [Sixth engagement part 26] A "sixth valley 46" which is a valley-shaped bent portion 4 is continuous with the second straight portion 12 on the second direction A2 side. The sixth valley 46 intersects with the sixth peak 36 which is a mountain-shaped bent portion 3 to form a "sixth engaging portion 26" which is an engaging portion 2.

[0048] Specifically, when viewed from the radial direction R of the stent 100, the sixth peak 36 and the sixth valley 46 intersect at an eleventh intersection G11 and a twelfth intersection G12. The eleventh intersection G11 is closer to the first straight line intersection 1A than the twelfth intersection G12. At the eleventh intersection G11, the sixth valley 46 passes on the outside of the sixth peak 36 in the radial direction R. At the twelfth intersection G12, the sixth valley 46 passes on the inside of the sixth peak 36 in the radial direction R.

[0049] [Arrangement of first hook portion 21, second hook portion 22, and third hook portion 23] The first engaging portion 21 and the second engaging portion 22 are disposed at different positions in the longitudinal axis direction A. Specifically, the second engaging portion 22 is disposed on the first direction A1 side of the first engaging portion 21 in the longitudinal axis direction A.

[0050] The second engaging portion 22 and the third engaging portion 23 are disposed at different positions in the longitudinal axis direction A. Specifically, the third engaging portion 23 is disposed on the second direction A2 side of the second engaging portion 22 in the longitudinal axis direction A.

[0051] [Arrangement of the fourth hook portion 24, the fifth hook portion 25, and the sixth hook portion 26] The fourth hooking portion 24 and the fifth hooking portion 25 are disposed at different positions in the longitudinal axis direction A. Specifically, the fifth hooking portion 25 is disposed on the second direction A2 side of the fourth hooking portion 24 in the longitudinal axis direction A.

[0052] The fifth hooking portion 25 and the sixth hooking portion 26 are disposed at different positions in the longitudinal axis direction A. Specifically, the sixth hooking portion 26 is disposed on the first direction A1 side of the fifth hooking portion 25 in the longitudinal axis direction A.

[0053] [Wire W] The first peak 31, the first straight portion 11, the fifth valley 45, the third straight portion 13, and the third peak 33 form a continuous portion (first wire W1) of the wire W extending in a zigzag manner along the circumferential direction C. The sixth valley 46, the second straight portion 12, the second peak 32, the fourth straight portion 14, and the fourth valley 44 form a continuous portion (second wire W2) of the wire W extending in a zigzag manner along the circumferential direction C. The first wire W1 and the second wire W2 may be a single continuous wire or may be different wires.

[0054] [Other straight line intersection 1 and engagement 2] The first straight line intersection 1A and the second straight line intersection 1B, which are adjacent straight line intersections 1, and the six hooks 2 (first hook 21, second hook 22, third hook 23, fourth hook 24, fifth hook 25, and sixth hook 26) connected to the first straight line intersection 1A and the second straight line intersection 1B have the above-mentioned configuration. As shown in Fig. 3, the hooks 2 connected to other adjacent straight line intersections 1 in the stent 100 have the same configuration as the above-mentioned configuration, except for the portions where the stepped intersections 15 are provided.

[0055] [Arrangement of the engagement portion 2 in the second region E2] 3, the hooking portions 2 arranged in the second region E2 in the circumferential direction C are disposed at different positions from adjacent hooking portions 2 in the longitudinal direction A. Specifically, the hooking portions 2 arranged in the second region E2 in the circumferential direction C are disposed alternately one by one in the longitudinal direction A.

[0056] FIG. 5 is a diagram for explaining the deviation L1 and the pitch L2. The length in the longitudinal direction A between the position of the hook 2 closest to the first direction A1 in the second region E2 and the position of the hook 2 closest to the second direction A2 in the same second region E2 is defined as "displacement L1." Here, the position of the hook 2 is the position of the center of the hook 2 in the stent 100 naturally expanded in a linear state.

[0057] The length in the longitudinal axis direction A of adjacent second regions E2 in the longitudinal axis direction A is defined as "pitch L2." Here, the length in the longitudinal axis direction A of two second regions E2 is the distance between the central axes EO of the second regions E2. The central axis EO is a straight line parallel to the circumferential direction C that passes through the midpoint in the longitudinal axis direction A between the position of the engaging portion 2 closest to the first direction A1 in the second region E2 and the position of the engaging portion 2 closest to the second direction A2 in the same second region E2.

[0058] [Operation of stent delivery system 150] A stent placement method using an endoscope system 300 including a stent delivery system 150 will be described using a procedure for placing a stent 100 in a bile duct as an example.

[0059] FIG. 6 is a cross-sectional view of the distal portion of a stent delivery system 150. The stent 100 is accommodated in the gap between the inner tube member 120 and the outer tube member 110 in a state where the diameter of the stent 100 is reduced in the radial direction R. In the hooking portions 2 where the wire W overlaps a lot, the wire W is more likely to be bulky in the radial direction R than in other portions of the stent 100 in a state where the diameter of the stent 100 is reduced in the radial direction R. However, in the second region E2 of the stent 100, the hooking portions 2 are arranged dispersedly in the longitudinal axis direction A, so that the bulkiness of the wire W in the radial direction R can be reduced. Therefore, the stent 100 can be easily accommodated in a stent delivery system.

[0060] FIG. 7 is a diagram showing a stent 100 with a large deviation L1. The larger the offset L1, the more the stent 100 can reduce the bulkiness of the wire W in the radial direction R in the state contracted in the radial direction R shown in FIG. 6. Here, it is desirable that the offset L1 is equal to or less than half the pitch L2. When the offset L1 is half the pitch L2, the bulkiness is reduced to the greatest extent. When the offset L1 is greater than half the pitch L2, the shape conformability of the hooking portions 2 arranged in the circumferential direction C in the second region E2 decreases.

[0061] The surgeon inserts the insertion portion 210 of the endoscope 200 into the body cavity of the patient through a natural opening such as the mouth. At that time, the surgeon bends the bending portion 212 by operating the knob 223 or the like as necessary.

[0062] The surgeon passes a guidewire through the treatment tool channel 230 of the endoscope 200 and inserts the guidewire into the bile duct while observing with the endoscope 200. Next, the surgeon operates the guidewire under X-ray fluoroscopy to break through the stricture site in the bile duct, and moves the tip of the guidewire toward the liver side from the stricture site (target position).

[0063] The surgeon inserts the proximal end of the guide wire protruding from the forceps plug 225 of the endoscope 200 into the through-hole of the tip 130 of the stent delivery system 150 .

[0064] The surgeon advances the stent delivery system 150 along the guidewire by pushing the stent delivery system 150 while holding the guidewire. The tip of the stent delivery system 150 protrudes from the tip of the treatment tool channel 230 of the endoscope 200. When the tip of the stent delivery system 150 breaks through the stenosis site (target position), the surgeon advances and retreats the stent delivery system 150 to determine the placement position of the stent 100. The surgeon may insert the stent delivery system 150 into the treatment tool channel 230 without using a guidewire.

[0065] After determining the target position of the stent 100, the surgeon retracts the outer tubular member 110 relative to the inner tubular member 120. As a result, as shown in FIG 1, the stent 100 is gradually exposed from the distal end side and expands.

[0066] In a state where the diameter is contracted in the radial direction R, the force of expanding the diameter is strong in the bulky portions of the hooking portions 2 where the wire W overlaps a lot. However, in the second region E2 of the stent 100, the hooking portions 2 are arranged dispersedly in the longitudinal axis direction A, so that the force of the hooking portions 2 trying to expand the diameter can be dispersed. Therefore, the sliding resistance between the housed stent and the outer tube member 110 of the stent delivery system 150 is small, making it easy to release.

[0067] When the stent 100 is completely exposed, the stent 100 expands entirely, and the inner diameter of the stent 100 becomes larger than the outer diameter of the inner cylindrical member 120. Accordingly, the engagement between the stent 100 and the inner cylindrical member 120 is released.

[0068] After the engagement between the stent 100 and the inner cylindrical member 120 is released, when the surgeon retracts the inner cylindrical member 120, the stent 100 remains in the placement position and the inner cylindrical member 120 is removed from the stent 100.

[0069] When the surgeon pulls out the stent delivery system 150 except for the stent 100 from the body, the procedure for placing the stent 100 is completed.

[0070] The stent 100 according to this embodiment has high shape conformability because it is provided with engaging portions 2 with many overlaps of the wire W. In addition, the stent 100 has engaging portions 2 with many overlaps of the wire W that are distributed in the longitudinal axis direction A, making it easy to accommodate the stent 100 in the stent delivery system 150 and easy to release from the stent delivery system 150.

[0071] Although the first embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design modifications and the like within the scope of the present invention are also included. In addition, the components shown in the above embodiment and the modified examples shown below can be appropriately combined to form a configuration.

[0072] (Variation 1-1) In the above embodiment, the hooking portions 2 arranged in the circumferential direction C in the second region E2 are arranged alternately one by one in the longitudinal axis direction A. However, the arrangement of the hooking portions 2 in the second region E2 is not limited to this. Figure 8 is a development view of a stent 100A, which is a modified example of the stent 100. The stent 100A differs from the stent 100 only in the arrangement of the hooking portions 2 in the second region E2.

[0073] In the stent 100A, the engaging portions 2 arranged in the circumferential direction C in the second region E2 are arranged at any one of a first position P1, a second position P2, and a third position P3 in the longitudinal axis direction A. The first position P1, the second position P2, and the third position P3 are arranged from the first direction A1 side toward the second direction A2 side.

[0074] From the first circumferential direction C1 to the second circumferential direction C2, a hooking portion 2 (2P1) arranged at a first position P1, a hooking portion 2 (2P2) arranged at a second position P2, and a hooking portion 2 (2P3) arranged at a third position P3 are repeatedly arranged. In the stent 100A, the hooking portions 2 with many overlaps of the wires W are arranged more dispersedly in the longitudinal axis direction A.

[0075] The multiple hooking portions 2 arranged in the circumferential direction C in the second region E2 may be distributed at four or more different positions in the longitudinal axis direction A. In addition, among the hooking portions 2 adjacent to each other in the circumferential direction C in the second region E2, the hooking portion 2 on the first circumferential direction C1 side may be disposed on the first direction A1 side or the second direction A2 side in the longitudinal axis direction A relative to the hooking portion 2 on the second circumferential direction C2 side.

[0076] Second Embodiment A second embodiment of the present invention will be described with reference to Figures 9 and 10. In the following description, components common to those already described will be given the same reference numerals and redundant description will be omitted. The stent 100B according to the second embodiment is accommodated in a stent delivery system 150, similar to the stent 100 according to the first embodiment.

[0077] FIG. 9 is a development view of the stent 100B developed in the circumferential direction C. As shown in FIG. The stent 100B, like the stent 100 of the first embodiment, is formed by weaving wires W and has a cylindrical shape. The stent 100B also has a plurality of linear intersections 1 and a plurality of engagement portions 2. The stent 100B differs from the stent 100 of the first embodiment only in the arrangement of the engagement portions 2.

[0078] [Arrangement of first hook portion 21, second hook portion 22, and third hook portion 23] FIG. 10 is an enlarged view of a region F2 shown in FIG. The first engaging portion 21 and the second engaging portion 22 are disposed at different positions in the longitudinal axis direction A. Specifically, the second engaging portion 22 is disposed on the first direction A1 side of the first engaging portion 21 in the longitudinal axis direction A.

[0079] The second engaging portion 22 and the third engaging portion 23 are disposed at different positions in the longitudinal axis direction A. Specifically, the third engaging portion 23 is disposed on the second direction A2 side of the second engaging portion 22 in the longitudinal axis direction A.

[0080] [Arrangement of the fourth hook portion 24, the fifth hook portion 25, and the sixth hook portion 26] The fourth hooking portion 24 and the fifth hooking portion 25 are disposed at different positions in the longitudinal axis direction A. Specifically, the fifth hooking portion 25 is disposed on the first direction A1 side of the fourth hooking portion 24 in the longitudinal axis direction A.

[0081] The fifth hooking portion 25 and the sixth hooking portion 26 are disposed at different positions in the longitudinal axis direction A. Specifically, the sixth hooking portion 26 is disposed on the second direction A2 side of the fifth hooking portion 25 in the longitudinal axis direction A.

[0082] The stent 100B according to this embodiment has high shape conformability because it is provided with engaging portions 2 with many overlaps of the wire W. Furthermore, the stent 100B has engaging portions 2 with many overlaps of the wire W that are distributed in the longitudinal axis direction A, making it easy to accommodate the stent 100B in the stent delivery system 150 and easy to release from the stent delivery system 150.

[0083] Although the second embodiment of the present invention has been described above in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and design modifications and the like that do not depart from the gist of the present invention are also included. Also, the components shown in the above embodiment and modified examples can be appropriately combined to form a configuration. EXAMPLES

[0084] The present invention will be described in detail below based on examples, but the technical scope of the present invention is not limited to these examples.

[0085] Example 1 is the stent 100 of the above embodiment. Comparative Example 1 is a stent in which the displacement L1 of the stent 100 is set to zero.

[0086] Expansion force measurement was performed using Example 1 and Comparative Example 1. The expansion force measurement was performed based on "4. Measurement of radial force" defined in JIS T3269. The stent placed in a 37°C bath was repeatedly subjected to alternating diameter contraction and diameter expansion of the entire stent.

[0087] FIG. 11 shows the results of the expansive force measurement of the stent 100. When the stent is in its most contracted state, the expansion force of Example 1 is smaller than that of Comparative Example 1. This is because in Example 1, the hooking portions 2 are arranged dispersedly in the longitudinal axis direction A in the second region E2, which reduces the bulk of the wire W in the radial direction R and distributes the force exerted by the hooking portions 2 to expand the diameter.

[0088] On the other hand, in the process of contracting and expanding the diameter, there is little difference in the expansive force between Example 1 and Comparative Example 1. That is, even when the deviation L1 of the stent 100 is provided as in Example 1, the basic function of the stent, that is, the function of pushing open a stenosis or blockage, can be maintained. [Industrial Applicability]

[0089] The present invention can be applied to a stent formed by braiding wires or the like. [Explanation of symbols]

[0090] 300 Endoscope System 200 Endoscope 150 Stent Delivery System 110 External cylinder member 120 Inner cylinder member 130 Chips 100, 100A, 100B Stents 1 Straight intersection 10 Straight section 11 First straight section 12 Second straight section 13 Third straight section 14 Fourth straight section 15 Step-shift intersection 1A First straight intersection 1B Second straight-line intersection part 2 Engaging part (interlocking part) 21 First engaging part 22 Second engaging part 23 Third engaging part 24 Fourth engaging part 25 Fifth engaging part 26 Sixth engaging part 3 Mountain-shaped bending part (mountain) 31 First mountain 32 Second mountain 33 Third mountain 34 Fourth mountain 35 Fifth mountain 36 Sixth mountain 4 Valley-shaped bending part (valley) 41 First valley 42 Second valley 43 Third valley 44 Fourth valley 45 Fifth valley 46 Sixth valley

Claims

1. A stent formed by braiding wires, a plurality of straight line intersections at which the straight line segments intersect; A plurality of engagement portions where a mountain-shaped bent portion bent toward a first direction side, which is one side of the axial direction, and a valley-shaped bent portion bent toward a second direction side, which is the other side of the axial direction, and are convex, intersect; Equipped with The plurality of straight line intersections include a first straight line intersection portion where the first straight line portion and the second straight line portion intersect; a second straight line intersection portion where the third straight line portion and the fourth straight line portion intersect; having The plurality of engagement portions are a first engaging portion where a first peak, which is the mountain-shaped bent portion connected to the first direction side of the first straight portion, and a first valley, which is the valley-shaped bent portion, intersect; a second engaging portion where a second peak, which is the mountain-shaped bent portion connected to the second straight portion and the fourth straight portion on the first direction side, and a second valley, which is the valley-shaped bent portion, intersect; a third engaging portion where a third peak, which is the mountain-shaped bent portion connected to the third straight portion on the first direction side, and a third valley, which is the valley-shaped bent portion, intersect; a fourth engaging portion where a fourth valley, which is the valley-shaped bent portion connected to the second direction side of the fourth straight portion, and a fourth peak, which is the mountain-shaped bent portion, intersect; a fifth engagement portion where a fifth valley, which is the valley-shaped bent portion connected to the first straight portion and the third straight portion on the second direction side, and a fifth peak, which is the mountain-shaped bent portion, intersect; A sixth valley that is the valley-shaped bent portion connected to the second direction side of the second straight portion and a sixth peak that is the mountain-shaped bent portion intersect with each other; and having The first engaging portion and the second engaging portion are disposed at different positions in the axial direction, The second engaging portion and the third engaging portion are disposed at different positions in the axial direction, The fourth engaging portion and the fifth engaging portion are disposed at different positions in the axial direction, The fifth engaging portion and the sixth engaging portion are disposed at different positions in the axial direction, the second engaging portion is disposed on the first direction side of the first engaging portion in the axial direction, The fifth engaging portion is disposed on the first direction side of the fourth engaging portion in the axial direction. Stent.

2. A first region in which the plurality of straight line intersections are arranged in a circumferential direction; The second region in which the plurality of engagement portions and one of the linear intersection portions are arranged in the circumferential direction is Alternatingly arranged in the axial direction, 2. The stent of claim 1.

3. The straight line intersections arranged in the second region are arranged at different positions in the circumferential direction. The stent of claim 2.

4. The length in the axial direction between the position of the engaging portion closest to the first direction side in the second region and the position of the engaging portion closest to the second direction side in the same second region is The length in the axial direction of the second region adjacent to the second region is equal to or less than half of the length in the axial direction. The stent of claim 2.

5. the third engaging portion is disposed on the first direction side of the second engaging portion in the axial direction, The sixth engaging portion is disposed on the first direction side of the fifth engaging portion in the axial direction.

2. The stent of claim 1.

6. the third engaging portion is disposed on the second direction side relative to the second engaging portion in the axial direction, The sixth engaging portion is disposed on the second direction side of the fifth engaging portion in the axial direction.

2. The stent of claim 1.

7. An operation unit; an outer tube member configured to extend distally from the operating portion; an inner tube member configured to extend distally from the operating portion and disposed inside the outer tube member; The stent according to claim 1 , which is housed between the outer tubular member and the inner tubular member. Equipped with The operation unit is configured to place the stent by moving the outer tubular member or the inner tubular member in a longitudinal direction. Stent delivery system.

8. The outer tube member is configured to be insertable into a channel of an endoscope. The stent delivery system of claim 7.

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