Stent delivery system

Abstract

[Problem] To provide a stent delivery system that can be smoothly removed together with a stent without causing entanglement of a thread-like part. [Solution] A stent delivery system 1 comprising a stent 10, an outer catheter 20, an inner catheter 30, a thread-like part 40, and an anchor part 50. The thread-like part 40 is joined to a first opening 14 and a second opening 15 on the rear end side of the stent 10, and the inner catheter 30 is inserted into a notch 23 in the outer catheter 20 so as to press the thread-like part 40 downward, whereby the stent 10 and the outer catheter 20 can be temporarily fixed. An anchor part 50 is connected to the distal end side of the thread-like part 40, the stent 10 is placed at a target site 101, and the anchor part 50 is brought into contact with the duodenal wall 104 on the outside of the bile duct 100, thereby preventing the stent from entering.

Description

Stent Delivery System

[0001] The present invention relates to a stent delivery system for use in biliary duct, pancreatic duct drainage and the like.

[0002] As a stent to be indwelled in a lumen, there has been proposed a tube stent that can be easily and safely removed from the indwelled state in the lumen, the tube stent including: a tube body having openings at a distal end and a proximal end thereof respectively; a flexible flap, one end of which is connected to the tube body and the other end of which is provided so as to protrude obliquely outward on the proximal end side of the tube body; and a thread member, one end of which is attached to the flap (see Patent Document 1).

[0003] Japanese Unexamined Patent Publication No. 2016-187366

[0004] However, after the above-described tube stent is indwelled in the lumen, the thread member may mistakenly enter the lumen. Further, when a locking flap is not provided on the proximal side of the stent, the stent may mistakenly enter the lumen together with the thread member. When such a situation occurs, there is a problem that the stent cannot be easily removed.

[0005] In view of the above circumstances, an object of the present invention is to provide a stent delivery system in which a thread member is less likely to mistakenly enter a lumen such as a biliary duct.

[0006] As a result of intensive research and development on the above-mentioned problems, the inventor of the present invention has found the following innovative stent delivery system.

[0007] A first aspect of the present invention for solving the above problems is a stent delivery system used for endoscopic surgery, comprising: a stent; an outer catheter; an inner catheter inserted through the stent and the outer catheter; a thread-like portion for temporarily fixing the stent and the outer catheter; and an anchor portion obtained by extending the thread-like portion to a lateral side of the stent and joining the extended thread-like portion at a distal end side thereof, wherein when the stent is inserted into a lumen having a target site, the anchor portion abuts against a body wall outside the lumen.

[0008] According to this first embodiment, the anchor portion abuts against the internal wall outside the tube, preventing the filamentous portion from becoming misplaced. As a result, the stent can be easily removed.

[0009] A second aspect of the present invention is a stent delivery system according to the first aspect, characterized in that the anchor portion has a semi-cylindrical shape having a predetermined length, and the inner diameter of the anchor portion is substantially the same as the outer diameter of the outer catheter.

[0010] In this second embodiment, since the inner diameter of the anchor portion is substantially the same as the outer diameter of the outer catheter, the anchor portion is in near-perfect contact with the outer wall of the outer catheter while the stent delivery system is passing through the channel of the endoscope. As a result, the anchor portion can move through the channel without separating from the outer catheter.

[0011] A third aspect of the present invention is a stent delivery system according to either the first or second aspect, characterized in that the anchor portion has two holes through which a filamentous portion passes, and a connecting portion through which the filamentous portion that has passed through the holes is tied on the inside of the anchor portion.

[0012] According to this third embodiment, the distance between the posterior end of the stent and the anchor portion can be adjusted by the presence of a connecting portion that links the thread-like parts of the anchor portion. The position of the target site is not fixed and changes depending on the patient's condition, so this can be accommodated. Furthermore, the connecting portion is formed by hand by the surgeon or other medical professional, and because it is located inside the anchor portion, it is easier to form without being obstructed by other components, and the formation state is easier to confirm.

[0013] A fourth aspect of the present invention is a stent delivery system according to either the first or second aspect, characterized in that the anchor portion has two holes through which a filamentous portion passes, and has a connecting portion to which the filamentous portion that has passed through the holes is connected on the inside of the anchor portion, and the connecting portion is provided near the central part of the anchor portion.

[0014] In this fourth embodiment, with the anchor portion in contact with the internal wall on the outside of the pipe containing the target area, both ends of the anchor portion can evenly contact the wall, and the placement of the anchor portion is stable.

[0015] A fifth aspect of the present invention is a stent delivery system according to the first or second aspect, characterized in that the anchor portion has a hole through which a filamentous portion passes, and a connecting portion on the outside of the anchor portion through which the filamentous portion that has passed through the hole is tied.

[0016] According to this fifth embodiment, the distance between the posterior end of the stent and the anchor portion can be adjusted by the presence of a connecting portion that links the thread-like parts of the anchor portion. This allows for adjustment as the location of the target site is not fixed and changes depending on the patient's condition.

[0017] A sixth aspect of the present invention is a stent delivery system according to the first aspect, characterized in that one end of the filamentous portion is connected to the rear end of the stent and the other end is connected to the anchor portion.

[0018] In this sixth embodiment, the outer catheter and the anchor portion are always connected by the filamentous portion, so they never separate. Furthermore, because the connection is at the posterior end of the stent, the filamentous portion does not become entangled with the outer catheter.

[0019] A seventh aspect of the present invention is a stent delivery system according to the second aspect, characterized in that a predetermined length of the anchor portion is formed to be larger than the outer diameter of the pipe where the target portion is located.

[0020] In this seventh embodiment, the anchor portion is not inserted into a pipe having an outer diameter smaller than a predetermined length of the anchor portion, and can be reliably brought into contact with the outer wall of the pipe where the target portion is located.

[0021] An eighth aspect of the present invention is a stent delivery system according to the second aspect, characterized in that the outer surface of the anchor portion is in contact with the wall inside the body.

[0022] In this eighth embodiment, the outer surface of the anchor portion is a curved surface with a semi-cylindrical circumference, so that the anchor portion can softly contact the outer wall of the tube where the target site is located without damaging it. During placement of the anchor portion, stable placement can be achieved without causing any burden to the patient.

[0023] Furthermore, these problems (issues) do not preclude the existence of other issues. Also, the embodiments of the present invention described later do not need to solve all of these problems (issues). Moreover, it is possible to extract other problems (issues) from the description, drawings, or claims.

[0024] This is a side view showing an example of the stent delivery system according to the present invention. Figure 1 shows the stent, with (a) a side view, (b) a cross-sectional view along A-A in (a), and (c) a cross-sectional view along B-B in (a). Figure 1 shows the outer catheter, with (a) a side view, (b) a cross-sectional view along A-A in (a), and (c) a cross-sectional view along B-B in (a). Figure 1 shows the inner catheter, with (a) a side view and (b) a cross-sectional view along A-A in (a). Figure 1 shows the anchor portion, with (a) a side view and (b) a cross-sectional view along A-A in (a). Figure 5 is a perspective view of the anchor portion. This is an explanatory diagram showing the relationship between the stent, outer catheter, inner catheter, filamentous portion, and anchor portion according to the present invention, with (a) showing the second opening side of the stent and (b) showing the first opening side of the stent, respectively. This is a schematic diagram showing an example of use of the stent delivery system according to the present invention, showing the state in which the tip side of the stent is close to the target site. Following Figure 8, (a) shows the stent positioned at the target site, and (b) shows the stent, filamentous portion, and anchor portion in place. This is an explanatory diagram illustrating bile duct drainage using the stent delivery system according to the present invention, and (a) shows the state of progress toward the target site, and (b) shows the stent, filamentous portion, and anchor portion in place with the target site as the center.

[0025] Embodiments of the stent delivery system according to the present invention will be described below with reference to the attached drawings. However, the present invention is not limited to the following embodiments.

[0026] (Embodiment 1) As shown in Figure 1, the stent delivery system 1 of the present invention comprises a stent 10, an outer catheter 20, an inner catheter 30, a thread-like portion 40, and an anchor portion 50, and may further comprise an operating unit 60. The operating unit 60 supports the outer catheter 20 and the inner catheter 30 and also performs operations on the guide wire W, etc. Note that the stent 10 may also be called a tube stent, the outer catheter 20 may be called a pusher catheter or pusher tube, the inner catheter 30 may be called a guide catheter or auxiliary tube, and the thread-like portion 40 may be called a thread, thread-like body, thread-like member, etc.

[0027] The stent 10 is one of the components of the stent delivery system 1. It is transported into the body along the guidewire W using the stent delivery system 1, and is used to expand the internal tubular portion of the stent towards a target site in the body (e.g., a stenotic area, an occluded area, etc.) from the inside, and is a medical device that is placed in the target site.

[0028] In the following explanation, to make the configuration easier to understand, the side with the operating section 60 will be referred to as the rear end, and the opposite side as the front end. The same applies to the configurations of the stent 10, outer catheter 20, and inner catheter 30.

[0029] As shown in Figure 2, the stent 10 comprises an annular stent tube wall portion 11, a hollow stent insertion portion 12 surrounded by the stent tube wall portion 11 and penetrating the stent 10, and a flap portion 13 formed protruding from the side surface of the stent tube wall portion 11. An inner catheter 30 is inserted into the stent insertion portion 12, and a guidewire W passes through the inner catheter insertion portion 32 of the inner catheter 30.

[0030] The rear end of the stent 10 has a first opening 14 and a second opening 15 that penetrate from the side inward. The first opening 14 is an opening through which the filamentous portion 40 passes, and the second opening 15 is formed opposite the first opening 14 and is an opening on which the filamentous portion 40 is placed. The sizes of the first and second openings are not particularly limited, but in this embodiment, the first opening 14 is formed to have a smaller opening area (diameter) compared to the second opening 15.

[0031] Furthermore, the first opening 14 is nearly circular in shape, while the second opening 15 has an oval shape along the longitudinal direction of the stent 10. The first opening 14 is simply an opening large enough for the filamentous portion 40 to pass through, while the second opening 15 is an opening that allows the filamentous portion 40 to move along the longitudinal outer surface of the stent 10. The formation of the second opening 15 restricts the movement of the filamentous portion 40 to positions other than the second opening 15. Note that the second opening 15 is optional.

[0032] Stent 10 can be of various types, such as straight type, inside type, or pigtail type, but in this embodiment, the straight type will be described. In Figure 1, the inner catheter 30 and guidewire W are shown by dashed lines.

[0033] As shown in Figure 3, the outer catheter 20 comprises an annular outer catheter tube wall portion 21, a hollow outer catheter insertion portion 22 surrounded by the outer catheter tube wall portion 21 and penetrating the outer catheter 20, and a notch portion 23 on the tip side of the outer catheter 20. The inner catheter 30 is inserted through the outer catheter insertion portion 22. The notch portion 23 has an oval shape along the longitudinal direction of the outer catheter 20 and is notched from one side wall of the outer catheter tube wall portion 21 toward the opposite side wall. Here, the size of the notch is not particularly limited. For example, when viewed from the side, the notch is large enough that approximately the side wall of the inner catheter 30 is visible when the inner catheter 30 is inserted into the outer catheter insertion portion 22.

[0034] As shown in Figure 4, the inner catheter 30 comprises an annular inner catheter tube wall portion 31 and a hollow inner catheter insertion portion 32 that is surrounded by the inner catheter tube wall portion 31 and penetrates the inner catheter 30. The inner catheter 30 is inserted through the stent insertion portion 12 and the outer catheter insertion portion 22. The guidewire W is then inserted through the inner catheter insertion portion 32.

[0035] The thread-like portion 40, as will be described in detail later, is formed from, for example, a nylon resin and is in the form of a long, thin thread. The thread-like portion 40 maintains a temporary fixation state between the stent 10 and the outer catheter 20 while the stent delivery system 1 is moving inside the body, and releases the temporary fixation state between the stent 10 and the outer catheter 20 when the stent 10 is placed in the target site inside the body. In this embodiment, the thread-like portion 40 is further connected to an anchor portion 50.

[0036] As shown in Figure 5, the anchor portion 50 has a semi-cylindrical shape with one end open, and the inner diameter of the anchor portion 50 is formed to be approximately the same as the diameter of the outer catheter tube wall portion 21. Two small cavities, or holes 51, are formed in the anchor portion 50 through which the filamentous portion 40 passes. The ends of the anchor portion 50 in the longitudinal direction will be described as the end portions 52, the area near the center as the central portion 53, the outer surface side as the outer portion 54, and the inner surface side as the inner portion 55.

[0037] Both ends 52 of the anchor portion 50 are inclined toward the central portion 53 toward the open side, and the length D1 on the open side is shorter than the length D of the generatrix. The length D of the generatrix is ​​formed to be larger than the outer diameter of a tube, such as a bile duct, where the target site into which the stent 10 will be inserted is located.

[0038] While the stent delivery system 1 is moving inside the endoscope, the anchor portion 50 is in contact with the outer wall of the outer catheter tube 21 (see Figure 1). As will be described later, when the stent 10 is placed in the target site, the stent 10 comes into contact with the end of the tube in the human body into which it is inserted. This contact occurs when the filamentous portion 40 supports the anchor portion 50, and both ends 52 come into contact with the wall as if it were clinging to the outer wall of the tube.

[0039] The hole 51 is preferably formed in the central part 53 of the anchor portion 50, as shown in Figure 6. This ensures that the anchor portion 50 is stably positioned in the state described above when the hole 51 is in the central part 53.

[0040] The stent 10, outer catheter 20, inner catheter 30, and anchor portion 50 are molded from resin. The resin is selected from, for example, polyamide elastomer resin, polyethylene elastomer resin, polyethylene resin, polystyrene elastomer, or polyurethane elastomer resin.

[0041] Next, with reference to Figure 7, we will explain how the stent 10, outer catheter 20, and anchor portion 50 are connected by the filamentous portion 40. Note that the present invention is not limited to the following connection method.

[0042] The thread-like portion 40 is hooked onto the second opening 15 of the stent 10 in a direction perpendicular to the longitudinal direction of the second opening 15, straddling the second opening 15 from the outside. With the inner catheter 30 inserted into the stent 10, the thread-like portion 40 is in contact with the outer wall of the inner catheter 30 (see Figure 7(a)). Then, the thread-like portion 40 is passed through the first opening 14 from the outside to the inside and inserted into the stent insertion section 12, and the thread-like portion 40 is pulled out from the rear end side of the stent 10. With the inner catheter 30 inserted into the stent 10, the thread-like portion 40 is sandwiched between the inner wall of the stent insertion section 12 and the outer wall of the inner catheter tube wall 31 (see Figure 7(b)).

[0043] Then, one of the thread-like portions 40 extending from the rear end of the stent 10 is hooked onto the tip of the outer catheter 20 at the notch 23 of the outer catheter 20, and the inner catheter 30 is inserted into the outer catheter insertion section 22 by pressing the thread-like portion 40 downwards at the notch 23. With the inner catheter 30 inserted into the outer catheter 20, the thread-like portion 40 is sandwiched between the inner wall of the outer catheter insertion section 22 and the outer wall of the inner catheter tube wall 31 below the notch 23 (see Figure 7(b)). As a result, the thread-like portion 40 will not detach from the outer catheter 20 unless the inner catheter 30 is removed, and the temporary fixation between the stent 10 and the outer catheter 20 can be maintained.

[0044] Next, a knot 41 is formed in the two filamentous portions 40 on the outer side of the inner catheter tube wall portion 31 and between the rear end side of the stent 10 and the distal end side of the outer catheter 20, each of the filamentous portions 40 is passed through the two holes 51 of the anchor portion 50 at positions away from the knot 41, and a joint portion 42 is formed by tying each filamentous portion 40 on the inner side 55 of the anchor portion 50.

[0045] Through the above procedure, the stent 10 can be temporarily fixed by the filamentous portions 40, and the anchor portion 50 is always in a state of being connected to the filamentous portions 40, so that the anchor portion 50 is disposed at a spaced apart position on the lateral side of the stent 10. In other words, one end of each filamentous portion 40 is connected to the rear end side of the stent 10, and the other end is connected to the anchor portion 50. Further, when the stent 10 is placed at a target site, the outer catheter 20 and the inner catheter 30 can be separated by extracting the inner catheter 30, and the filamentous portions 40 are also detached from the outer catheter 20.

[0046] As described above, the stent 10 and the anchor portion 50 are always in a state of being connected to each other via the filamentous portions 40. That is, the anchor portion 50 is connected to the distal end side of the filamentous portion 40 extending to the lateral side of the stent 10. One end of the filamentous portion 40 is connected so as to straddle the second opening 15 on the rear end side of the stent 10, and the other end is connected to the anchor portion 50 via a connecting portion 42 formed in the anchor portion 50.

[0047] The distance from the second opening 15 can be adjusted at the position of the knot 41, and the distance between the rear end side of the stent 10 and the distal end side of the outer catheter 20 can also be adjusted. The strength of the temporary fixation can be determined by adjusting said distance. Further, the distance L between the stent 10 and the anchor portion 50 can be adjusted at the position of the connecting portion 42.

[0048] Furthermore, as an example of the stent delivery system 1 of the present embodiment, endoscopic retrograde biliary drainage (ERBD) will be described. Endoscopic retrograde biliary drainage is a treatment in which an endoscope is inserted through the mouth, the stent 10 is placed at a target site, and the pressure in the bile duct at the portion where cholestasis occurs due to acute cholangitis, stones, tumors, or the like is reduced.

[0049] The effects of the filamentous portion 40 and the anchor portion 50 will be described in detail based on Figures 8 and 9.

[0050] The guidewire W is inserted into a narrowed portion of the bile duct 100, such as a site of cancer (narrowing site, target site) 101. The stent delivery system 1 is guided along the guidewire W toward the narrowing site 101 and inserted into the bile duct 100 from the stent 10 (see Figure 8). While the stent delivery system 1 in the endoscope is passing through a channel through which it can be inserted, the anchor portion 50 is in contact with the outer wall of the outer catheter tube 21 as shown in Figure 1. However, with the tip of the stent 10 and outer catheter 20 protruding from the endoscope, the anchor portion 50 is free within the duodenum 102 (see Figure 8).

[0051] Next, the stent 10 is inserted into the narrowed area 101, expanding the narrowed area 101. This allows the bile that was stagnant in the narrowed area 101 to be discharged into the duodenum 102 through the stent insertion section 12. The anchor portion 50 is connected to the filamentous portion 40 which is connected to the stent 10 and the outer catheter 20, so it moves as it is pulled by the movement of the posterior end of the stent 10, and both ends 52 of the outer 54 of the anchor portion 50 come into contact with the duodenal wall 104 of the duodenum 102 surrounding the duodenal papilla 103, which is the opening of the bile duct and pancreatic duct (see Figure 9(a)).

[0052] Then, when the inner catheter 30 is removed, the filamentous portion 40 detaches from the outer catheter 20, and by removing the outer catheter 20 and the guidewire W, the stent 10 is placed near the target site, the stenotic site 101, and the anchor portion 50 is also placed near the duodenal papilla 103 (see Figure 9(b)).

[0053] When it is time to remove the stent 10, such as for replacement, the stent 10 can be easily removed from the bile duct 100 by grasping the anchor portion 50 and pulling it. Since the anchor portion 50 is placed on the duodenal wall 104 outside the bile duct 100 where the target site 101 is located, there is no need to insert any instruments into the bile duct 100, and the stent 10 can be easily removed at the same time by simply pulling out the anchor portion 50, without the filamentous portion 40 becoming entangled.

[0054] Because the inner diameter of the anchor portion 50 is almost the same as the outer diameter of the outer catheter 20, the anchor portion 50 is in almost perfect contact with the outer wall of the outer catheter 20 while the stent delivery system 1 is passing through the channel of the endoscope. As a result, the anchor portion 50 can be easily moved through the channel without separating from the outer wall of the outer catheter 20.

[0055] The stent 10 and anchor portion 50 are stationary in their predetermined positions, and the thread-like portion 40 connecting the stent 10 and the anchor portion 50 is under tension within the bile duct 100 and is in a nearly straight line within the bile duct 100. This prevents the thread-like portion 40 from becoming entangled with the outer catheter 20 or inner catheter 30 when the outer catheter 20 or inner catheter 30 is removed. Furthermore, the thread-like portion 40 does not become entangled within the bile duct 100 while the stent 10 and anchor portion 50 are in place, allowing for safe placement of the stent 10 and anchor portion 50. It goes without saying that the thread-like portion 40 connecting the stent 10 and the anchor portion 50 does not necessarily need to be under constant tension within the bile duct 100.

[0056] The distance L between the posterior end of the stent 10 and the anchor portion 50 can be adjusted by the presence of a connecting portion 42 that connects the thread-like portions 40 of the anchor portion 50. The position of the target site 101 is not constant and changes depending on the patient's condition, so this can be accommodated. Furthermore, the connecting portion 42 is located on the inside 55 of the anchor portion 50, on the open side of the semi-cylindrical anchor portion 50, which facilitates the formation of the connecting portion 42.

[0057] The position of the hole 51 in the anchor portion 50 is in the central portion 53, allowing both ends 52 to evenly contact the duodenal wall 104 around the duodenal papilla 103, thus ensuring stable placement of the anchor portion 50. The surface of the anchor portion 50 that contacts the duodenal wall 104 is the outer surface 54, which is a curved surface with a semi-cylindrical circumference, allowing for soft contact without damaging the duodenal wall 104. Furthermore, since the length D of both ends 52 of the anchor portion 50 is larger than the outer shape of the bile duct 100, the anchor portion 50 does not enter the bile duct 100 and reliably contacts the duodenal wall 104 near the duodenal papilla 103.

[0058] Furthermore, the use of the stent delivery system 1 of this embodiment will be explained using bile duct drainage as an example, based on Figure 10.

[0059] While manipulating the endoscope to confirm within the endoscopic field of view or under X-ray fluoroscopy, the tip of the guidewire W is inserted into the duodenal papilla 103 and advanced to a position where it has passed the target site 101 in the bile duct (or pancreatic duct) 100. Next, the inner catheter 30 is inserted into the stent 10 and outer catheter 20, the stent 10 and outer catheter 20 are temporarily secured with the thread-like portion 40, and the guidewire W is inserted into the inner catheter insertion section 32 from the posterior end of the guidewire W.

[0060] Then, the anchor portion 50 is brought into contact with the outer wall of the outer catheter 20, and the stent 10, outer catheter 20, inner catheter 30, filamentous portion 40, and anchor portion 50 are inserted into the channel of the endoscope. Next, the stent delivery system 1 is moved inside the body along the guidewire W, and the stent 10, outer catheter 20, inner catheter 30, filamentous portion 40, and anchor portion 50 are brought out of the channel of the endoscope into the body.

[0061] While confirming the position within the field of view using an endoscope, the tip of the stent 10 is inserted from the duodenal papilla 103 into the bile duct 100 (see Figure 10(a)).

[0062] Next, the tip of the stent 10 is advanced and penetrated through the target site 101. At this time, it is confirmed that both ends 52 of the anchor portion 50 are in contact with the duodenal wall 104. The guidewire W, inner catheter 30, and outer catheter 20 are withdrawn separately from the body, and the placement positions of the stent 10 and anchor portion 50 are reconfirmed with an endoscope (see Figure 10(b)).

[0063] The placement of the stent 10 is checked within the field of view of the endoscope or under X-ray fluoroscopy. If the stent 10 becomes occluded, if a problem occurs with its placement, or if the placement of the stent 10 is no longer necessary, the stent 10 is removed from the body using the anchor portion 50.

[0064] As explained above, the stent 10 and the anchor portion 50 are at an appropriate distance from each other, so that the stent 10 does not become entangled in the bile duct 100 during and after placement at the target site 101, and the stent 10 can be easily removed via the anchor portion 50.

[0065] (Other Embodiments) In Embodiment 1, two small cavities, or holes, through which the filamentous portion passes were formed in the anchor portion, but the present invention is not limited thereto. In a configuration similar to Embodiment 1, for example, only one small cavity, or hole, through which the filamentous portion passes may be formed in the anchor portion. Then, the tip of the filamentous portion is passed through the anchor portion from the outside (convex side surface) to the inside (concave side surface), and the tip of the filamentous portion is pulled out in the short direction (width direction) of the anchor portion. Then, the filamentous portion and the anchor portion may be joined by connecting the tip of the filamentous portion with the filamentous portion located on the outside of the anchor portion. The same effects as in Embodiment 1 can be obtained even in this way.

[0066] Furthermore, the present invention is not limited to the embodiments described above, and can be modified, improved, etc., as appropriate. In addition, the material, shape, dimensions, numerical values, form, number, placement, etc. of each component in the embodiments described above are arbitrary and not limited, as long as they can achieve the present invention.

[0067] 1 Stent delivery system 10 Stent 11 Stent tube wall 12 Stent insertion section 13 Flap section 14 First opening 15 Second opening 20 Outer catheter 21 Outer catheter tube wall 22 Outer catheter insertion section 23 Notch 30 Inner catheter 31 Inner catheter tube wall 32 Inner catheter insertion section 40 Thread-like section 41 Knot 42 Joint 50 Anchor section 51 Hole 52 End 53 Center 54 Outer side 55 Inner side 60 Manipulation section 100 Bile duct 101 Stenosis (target site) 102 Duodenum 103 Duodenal papilla 104 Duodenal wall W Guidewire

Claims

1. A stent delivery system for use in endoscopic surgery, comprising: a stent; an outer catheter; an inner catheter that passes through the stent and the outer catheter; a thread-like portion for temporarily securing the stent and the outer catheter; and an anchor portion that extends the thread-like portion laterally to the stent and is joined at the tip of the extended portion, wherein the stent abuts against the internal body wall outside the tube when inserted into a tube containing a target site.

2. The stent delivery system according to claim 1, characterized in that the anchor portion has a semi-cylindrical shape having a predetermined length, and the inner diameter of the anchor portion is substantially the same as the outer diameter of the outer catheter.

3. The stent delivery system according to claim 1 or 2, characterized in that the anchor portion has two holes through which the filamentous portion passes, and has a connecting portion on the inside of the anchor portion through which the filamentous portion that has passed through the holes is connected.

4. The stent delivery system according to claim 1 or 2, characterized in that the anchor portion has two holes through which the filamentous portion passes, and has a connecting portion to which the filamentous portion that has passed through the holes is connected inside the anchor portion, and the connecting portion is provided near the central part of the anchor portion.

5. The stent delivery system according to claim 1 or 2, characterized in that the anchor portion has one hole through which the filamentous portion passes, and the filamentous portion that has passed through the hole has a connecting portion on the outside of the anchor portion.

6. The stent delivery system according to claim 1, characterized in that one end of the filamentous portion is connected to the rear end of the stent and the other end is connected to the anchor portion.

7. The stent delivery system according to claim 2, characterized in that the predetermined length of the anchor portion is formed to be larger than the outer diameter of the pipe in which the target portion is located.

8. The stent delivery system according to claim 2, characterized in that the outer surface of the anchor portion abuts against the wall inside the body.

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