Medical instrument

Abstract

Provided is a medical instrument that includes an in-vivo indwelling tube that is easily inserted through a constricted site or a blocked site.　The medical instrument includes: an in-vivo indwelling tube that has a longitudinal direction and has a proximal end and a distal end; and an inner tubular member that is disposed in the lumen of the in-vivo indwelling tube, has a longitudinal direction, and has a proximal end and a distal end. The in-vivo indwelling tube has at least an inner diameter Sd1 and an inner diameter Sd2 smaller than the inner diameter Sd1. The position of the inner diameter Sd2 in the longitudinal direction is further on the distal side than the position of the inner diameter Sd1. The inner tubular member is movable in the longitudinal direction in the lumen of the in-vivo indwelling tube, but the distal end of the inner tubular member cannot be moved further toward the distal side than the distal end of the in-vivo indwelling tube.

Description

medical equipment

[0001] The present invention relates to a medical device including an in-vivo indwelling tube.

[0002] Living lumen such as blood vessels or digestive tracts, including the bile duct and pancreatic duct, may become narrowed or blocked for various reasons. A known method for treating various diseases caused by narrowing or obstruction involves placing a tubular stent at the narrowed or obstructed site, dilating the narrowed or obstructed site from the inside, and widening the living lumen. For example, when narrowing or obstruction occurs in the bile duct, a bile duct tube stent is delivered to the narrowed or obstructed site. The tube stent delivered to the narrowed or obstructed site remains in place and expands the narrowed or obstructed site from the inside. Placing the stent widens the inner diameter of the bile duct at the narrowed or obstructed site, thereby improving the narrowing or obstruction. This allows bile to be discharged from the bile duct to the duodenum, enabling the treatment of various diseases caused by narrowing or obstruction of the bile duct, such as biliary atresia, jaundice, and biliary tract cancer. Medical devices having such tube stents are described, for example, in Patent Documents 1 to 3.

[0003] Patent Document 1 describes a drainage tube retaining device (endoscopic treatment tool) that includes a guide catheter (elongated portion) through which a guidewire can be inserted and that slidably supports a drainage tube, a pusher tube (hollow portion) that is slidably disposed on the outside of the guide catheter, a pusher mouthpiece (connection portion) that is disposed at the rear end of the pusher tube and that positions the rear end of the pusher tube by connecting it to the operation section of the endoscope so that the insertion direction of the pusher tube into the channel and the removal direction of the guide catheter from the channel relative to the pusher tube are approximately the same, and a mouthpiece that is disposed at the rear end of the guide catheter. In Patent Document 1, the guide catheter is long enough to protrude beyond the drainage tube when the pusher tube and the drainage tube are fitted over the outer peripheral surface of the guide catheter.

[0004] Patent Document 2 describes a tube stent delivery device having an inner catheter with a tube stent attached to the outer periphery of its distal end so as to be freely axially movable, and an outer catheter attached to the outer periphery of the inner catheter located on the proximal end side of the tube stent so as to be freely axially movable. In Patent Document 2, the inner catheter is capable of being inserted through a through-hole in the tube stent.

[0005] Patent document 3 describes a stent kit comprising a tube stent having a stent arc portion at least one end of which is made up of at least a portion of an arc, and an inner catheter having an inner arc portion of the same shape as the stent arc portion, the inner arc portion being inserted into the tube stent so that the positions of the inner arc portion and the stent arc portion are aligned.

[0006] Japanese Patent Publication No. 2006-204476 Japanese Patent No. 6322374 Japanese Patent No. 5408682

[0007] The endoscopic treatment tool described in Patent Document 1 has a guide catheter disposed in the lumen of a drainage tube, and the distal end of the guide catheter is configured to be movable distally beyond the distal end of the drainage tube. The tube stent delivery device described in Patent Document 2 has an inner catheter disposed in the lumen of a tube stent, and the distal end of the inner catheter is configured to be movable distally beyond the distal end of the tube stent. Figure 1 of Patent Document 3 shows an embodiment in which an inner catheter 22 is inserted into a stent 12, and the distal end of the inner catheter 22 is disposed distally beyond the distal end of the stent 12. A similar embodiment is also shown in Figure 5 of Patent Document 3. Thus, in Patent Documents 1 to 3, the distal end of an inner cylindrical member such as a guide catheter or inner catheter disposed in the lumen of a tube stent is configured to be movable distally beyond the distal end of the tube stent.

[0008] In the case of a tube stent, an inner cylindrical member is inserted along a guide wire that has been inserted into a living lumen in advance, and the tube stent is then inserted along the inserted inner cylindrical member. In this case, a step occurs between the guide wire and the inner cylindrical member, and a step also occurs between the inner cylindrical member and the tube stent, resulting in two steps. In particular, the latter step has been reported to cause insertion resistance in clinical practice, making it difficult to insert the tube stent into a stenotic or occluded area.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a medical device including an in-vivo indwelling tube that can be easily inserted into a stricture or obstruction site.

[0010] The present invention is as follows. [1] A medical device including an in-vivo tube having a longitudinal direction and a proximal end and a distal end, and an inner tubular member having a longitudinal direction and a proximal end and a distal end, the inner tubular member being disposed in the lumen of the in-vivo tube, the inner tubular member having at least an inner diameter Sd1 and an inner diameter Sd2 smaller than the inner diameter Sd1, the position of the inner diameter Sd2 in the longitudinal direction being distal to the position of the inner diameter Sd1, the inner tubular member being movable in the longitudinal direction within the lumen of the in-vivo tube, but the distal end of the inner tubular member being unable to move distal to the distal end of the in-vivo tube. [2] The medical device according to [1], wherein the distal end of the inner tubular member is disposed in a section from the distal end of the in-vivo tube to a position that is 50% of the longitudinal length of the in-vivo tube. [3] The medical device according to [1] or [2], wherein a space is formed between the distal end of the inner tubular member and the inner wall of the indwelling tube in the longitudinal direction of the indwelling tube. [4] The medical device according to any of [1] to [3], wherein the inner diameter of the indwelling tube in the space is larger than the outer diameter of the distal end of the inner tubular member. [5] The medical device according to any of [1] to [4], wherein movement of the inner tubular member in the distal direction in the longitudinal direction within the lumen of the indwelling tube is restricted. [6] The medical device according to any of [1] to [5], wherein the medical device further includes an outer tubular member having a longitudinal direction, the outer tubular member being disposed outside the inner tubular member proximal to the proximal end of the indwelling tube, and the outer tubular member and the inner tubular member being fixed on the proximal side. [7] The medical device according to any one of [1] to [6], wherein the minimum inner diameter of the indwelling tube is smaller than the maximum outer diameter of the inner cylindrical member in a section from the distal end of the inner cylindrical member to a position 40 cm proximal to the distal end. [8] The medical device according to any one of [1] to [7], wherein the indwelling tube has a thick-walled portion in the longitudinal direction, the thick-walled portion being located distal to the distal end of the inner cylindrical member. [9] The medical device according to any one of [1] to [8], wherein the indwelling tube is a plastic tube stent to be placed in the bile duct or pancreatic duct.

[10] The medical device according to any one of [1] to [9], wherein the indwelling tube has an arcuate portion curved in an arc shape and a non-arcuate portion proximal to the arcuate portion.

[11] The medical device according to

[10] , wherein the arcuate portion of the indwelling tube is configured as a closed ring in plan view.

[12] The medical device according to any one of [1] to

[11] , wherein the distal end of the inner cylindrical member cannot move distally beyond the distal end of the indwelling tube.

[13] The medical device according to any of [1] to

[12] , further comprising an outer tubular member having a longitudinal direction, and a filament, the outer tubular member being disposed outside the inner tubular member proximal to the proximal end of the indwelling tube and movable in the longitudinal direction of the inner tubular member, the outer tubular member having a through-hole in a side wall of a distal portion of the outer tubular member, the indwelling tube having a through-hole in a side wall of a proximal portion of the indwelling tube, the filament being configured as a closed ring that passes through the through-hole of the outer tubular member, a part of the distal end of the outer tubular member distal to the through-hole of the outer tubular member being disposed within the ring, and the ring of the filament being passed through the through-hole of the indwelling tube, and the inner tubular member being disposed within the ring.

[0011] The medical device according to the present invention includes an in-vivo indwelling tube and an inner tubular member, the in-vivo indwelling tube having a specific internal structure, and the distal end of the inner tubular member is configured to be unable to move distally beyond the distal end of the in-vivo indwelling tube. Since the distal end of the inner tubular member cannot move distally beyond the distal end of the in-vivo indwelling tube, it is possible to eliminate the step between the inner tubular member and the in-vivo indwelling tube, which has traditionally caused insertion resistance. As a result, it is easier to insert the in-vivo indwelling tube through a stricture or occlusion.

[0012] FIG. 1 is a cross-sectional view showing an embodiment of a medical device according to the present invention. FIG. 2 is a cross-sectional view showing another embodiment of a medical device according to the present invention. FIG. 3 is a cross-sectional view showing another embodiment of a medical device according to the present invention. FIG. 4 is a cross-sectional view showing another embodiment of a medical device according to the present invention. FIG. 5 is a cross-sectional view showing another embodiment of a medical device according to the present invention. FIG. 6 is a cross-sectional view showing another embodiment of a medical device according to the present invention. FIG. 7 is a cross-sectional view showing another embodiment of a medical device according to the present invention. FIG. 8 is a cross-sectional view showing another embodiment of a medical device according to the present invention. FIG. 9 is a cross-sectional view showing another embodiment of a medical device according to the present invention. FIG. 10 is a schematic view for explaining a determination method. FIG. 11 is a schematic view for explaining a determination method. FIG. 12 is a schematic view for explaining a determination method. FIG. 13 is a cross-sectional view showing another embodiment of a medical device according to the present invention. FIG. 14 is a cross-sectional view showing another embodiment of a medical device according to the present invention. FIG. 15 is a cross-sectional view showing another embodiment of a medical device according to the present invention.

[0013] A medical device in an embodiment of the present invention includes an in-vivo tube having a longitudinal direction and a proximal end and a distal end, and an inner tubular member having a longitudinal direction and a proximal end and a distal end, the inner tubular member being disposed in the lumen of the in-vivo tube, the inner tubular member having at least an inner diameter Sd1 and an inner diameter Sd2 smaller than the inner diameter Sd1, the position of the inner diameter Sd2 in the longitudinal direction being distal to the position of the inner diameter Sd1, and the inner tubular member being movable in the longitudinal direction within the lumen of the in-vivo tube, but the distal end of the inner tubular member being unable to move distal to the distal end of the in-vivo tube.

[0014] The present invention will be described in more detail below based on the embodiments, but the present invention is not limited to the following embodiments. Of course, modifications can be made within the scope of the above and below-described purposes, and all such modifications are included within the technical scope of the present invention. In addition, hatching and component symbols may be omitted in the drawings for convenience. In such cases, reference should be made to the specification and other drawings. Furthermore, the dimensions of various components in the drawings may differ from actual dimensions, as priority is given to helping understand the features of the present invention.

[0015] FIG. 1 is a cross-sectional view showing an embodiment of a medical device according to the present invention. The medical device 1 shown in FIG. 1 includes an indwelling tube 10 and an inner tubular member 20. The indwelling tube 10 has a longitudinal direction and a proximal end 10a and a distal end 10b. The inner tubular member 20 has a longitudinal direction and a proximal end 20a and a distal end 20b. The proximal end 10a of the indwelling tube 10 and the proximal end 20a of the inner tubular member 20 refer to the end on the user side (the operator side), while the distal end 10b of the indwelling tube 10 and the distal end 20b of the inner tubular member 20 refer to the end on the opposite side of the proximal end (i.e., the end on the treatment target side). The direction from the proximal end 10a to the distal end 10b of the indwelling tube 10 and the direction from the proximal end 20a to the distal end 20b of the inner tubular member 20 are referred to as the longitudinal direction. A part of the inner cylindrical member 20 is disposed in the lumen of the indwelling tube 10. A guide wire 9 is disposed in the lumen of the indwelling tube 10 and the inner cylindrical member 20.

[0016] 1 , the indwelling tube 10 has at least an inner diameter Sd1 and an inner diameter Sd2 that is smaller than the inner diameter Sd1, and the position of the inner diameter Sd2 in the longitudinal direction of the indwelling tube 10 is distal to the position of the inner diameter Sd1. Furthermore, the inner tubular member 20 is movable in the longitudinal direction within the lumen of the indwelling tube 10, but the distal end of the inner tubular member 20 cannot move distal to the distal end 10b of the indwelling tube 10. As a result, the distal end of the inner tubular member 20 cannot move distal to the distal end 10b of the indwelling tube 10, which eliminates the step between the inner tubular member 20 and the indwelling tube 10 that has traditionally caused insertion resistance, making it easier to insert the indwelling tube 10 through a stenotic or occluded site.

[0017] The distal end of the inner cylindrical member 20 refers to the region from the distal end 20b of the inner cylindrical member 20 to a position 60 mm longitudinally proximal to the distal end 20b of the inner cylindrical member 20. As will be described later, an outer diameter expansion region or an inner diameter expansion region may be formed at the distal end of the inner cylindrical member 20. Furthermore, as will be described later, an X-ray opaque marker may be formed at the distal end of the inner cylindrical member 20.

[0018] When the maximum outer diameter at the distal end of the inner tubular member 20 is CD1, the maximum outer diameter CD1 may be smaller than the inner diameter Sd2 of the indwelling tube 10. However, it is preferable that the maximum outer diameter CD1 be smaller than the inner diameter Sd1 of the indwelling tube 10 and larger than the inner diameter Sd2 of the indwelling tube 10. That is, the relationship Sd2<CD1<Sd1 preferably holds between the maximum outer diameter CD1 at the distal end of the inner tubular member 20, the inner diameter Sd1 of the indwelling tube 10, and the inner diameter Sd2 of the indwelling tube 10. This limits the distal movement of the distal end of the inner tubular member 20 in the longitudinal direction within the lumen of the indwelling tube 10. As a result, it is possible to eliminate the step between the inner tubular member 20 and the indwelling tube 10, which has traditionally caused insertion resistance, making it easier to insert the indwelling tube 10 through a stenotic or occluded site.

[0019] The movement of the inner cylindrical member 20 in the distal longitudinal direction within the lumen of the retained tube 10 may be restricted. As described above, the movement of the inner cylindrical member 20 may be restricted by the distal end 20 b of the inner cylindrical member 20 abutting against the inner wall of the retained tube 10, whereby the relationship Sd2<CD1<Sd1 holds between the maximum outer diameter CD1 at the distal end of the inner cylindrical member 20, the inner diameter Sd1 of the retained tube 10, and the inner diameter Sd2 of the retained tube 10; the movement of the inner cylindrical member 20 may be restricted by the inner cylindrical member 20 being fixed on the proximal side; or the movement of the inner cylindrical member 20 may be restricted by the inner cylindrical member 20 having a small outer diameter region 25 having a smaller diameter than the inner diameter of the retained tube 10 and a large outer diameter region 26 having a larger diameter, and the large outer diameter region 26 abutting against the retained tube 10.

[0020] When the inner cylindrical member 20 is fixed on the proximal side, for example, the proximal end of the inner cylindrical member 20 may be fixed to a handle or the like. The method for fixing the proximal end of the inner cylindrical member 20 to a handle or the like is not particularly limited, and for example, a connection mechanism such as a luer lock, coupler, or other fitting mechanism may be provided on the handle body, and the proximal end of the inner cylindrical member 20 may be fixed to the handle body via this. When fixing the proximal end of the inner cylindrical member 20 to a handle or the like, if the medical device 1 includes an outer cylindrical member 50 having a longitudinal direction as described below, the outer cylindrical member 50 and the inner cylindrical member 20 may be fixed on the proximal side.

[0021] When the movement of the inner tubular member 20 is restricted by fixing the inner tubular member 20 on the proximal side, it is preferable that, while the inner tubular member 20 is fixed, there is a space in the longitudinal direction of the indwelling tube 10 between the distal end 20b of the inner tubular member 20 and the inner wall of the indwelling tube 10. In particular, the presence of a space in the longitudinal direction between the distal end 20b of the inner tubular member 20 and a position distal thereto prevents the inner tubular member 20 from sinking into the indwelling tube 10 due to longitudinal pressure when the indwelling tube 10 is inserted into a living body, making it easier to remove the inner tubular member 20. Note that, even when the movement of the inner tubular member 20 is restricted by the large outer diameter region 26 of the inner tubular member 20 coming into contact with the indwelling tube 10, it is still preferable that there is a space in the longitudinal direction of the indwelling tube 10, and the same effect can be expected. Furthermore, when the indwelling tube 10 and the inner cylindrical member 20 do not come into contact with each other, the distal end of the inner cylindrical member 20 does not need to be rigid, and therefore the wall thickness may be thin.

[0022] Although the relationship between the distal end 20b of the inner cylindrical member 20 and the inner diameter of the indwelling tube 10 is not particularly limited, it is preferable that in the longitudinal space between the distal end 20b of the inner cylindrical member 20 and the space distal to it, the outer diameter of the distal end 20b of the inner cylindrical member 20 is smaller than the inner diameter Sd1 of the indwelling tube 10. This more effectively prevents the inner cylindrical member 20 from sinking into the indwelling tube 10.

[0023] The distal end 20b of the inner tubular member 20 cannot move distally beyond the distal end 10b of the indwelling tube 10. That is, the distal end 20b of the inner tubular member 20 is present in the lumen of the indwelling tube 10. The presence of the distal end 20b of the inner tubular member 20 in the lumen of the indwelling tube 10 eliminates a step between the guidewire 9 and the inner tubular member 20 and reduces the step between the guidewire 9 and the indwelling tube 10, making it easier to insert the indwelling tube 10 through a narrowed or obstructed site in a lumen of the body. Furthermore, when the distal end of the inner tubular member 20 is disposed in the lumen of the distal end of the indwelling tube 10, the strength of the distal end of the indwelling tube 10 is increased, making it easier to insert the indwelling tube 10 through a narrowed or obstructed site in a lumen of the body.

[0024] The distal end of the indwelling tube 10 refers to the region from the distal end 10b of the indwelling tube 10 to a position one-third of the longitudinal length L of the indwelling tube 10. When the longitudinal length L of the indwelling tube 10 is 180 mm or more, the distal end of the indwelling tube 10 may be the region from the distal end 10b of the indwelling tube 10 to a position 60 mm longitudinally proximal to the distal end 10b of the indwelling tube 10. The proximal end of the indwelling tube 10 refers to the region from the proximal end 10a of the indwelling tube 10 to a position one-third of the longitudinal length L of the indwelling tube 10. When the longitudinal length L of the indwelling tube 10 is 180 mm or more, the proximal end of the indwelling tube 10 may be the region from the proximal end 10a of the indwelling tube 10 to a position 60 mm away from the proximal end 10a of the indwelling tube 10 in the longitudinal direction distally. The longitudinal length L of the indwelling tube 10 refers to the length of the path of the central axis of the indwelling tube 10 in a plan view.

[0025] 1 , a space may be provided in the longitudinal direction of the indwelling tube 10 between the distal end 20b of the inner tubular member 20 and the inner wall of the indwelling tube 10. That is, the distal end 20b of the inner tubular member 20 and the inner wall of the indwelling tube 10 may not abut against each other. By providing a space in the longitudinal direction of the indwelling tube 10 between the distal end 20b of the inner tubular member 20 and the inner wall of the indwelling tube 10, the inner tubular member 20 does not sink into the indwelling tube 10, making it easier to remove the inner tubular member 20. Furthermore, the rigidity of the distal end of the indwelling tube 10 can be reduced.

[0026] The size of the space formed in the longitudinal direction of the indwelling tube 10 is not particularly limited, but the shortest distance G between the distal end 20b of the inner tubular member 20 and the inner wall of the indwelling tube 10 in the longitudinal direction of the indwelling tube 10 is, for example, preferably 3 mm or more, more preferably 5 mm or more, and even more preferably 10 mm or more. If the shortest distance G of the space in the longitudinal direction of the indwelling tube 10 is too short, the inner tubular member 20 will easily sink into the indwelling tube 10. There is also no particular upper limit to the shortest distance G, but it is preferably 15 mm or less, for example. If the shortest distance G of the space in the longitudinal direction of the indwelling tube 10 is too long, the rigidity of the medical device 1 will easily decrease in the space.

[0027] 15 , the medical device 1 may have a structure in which an outer tubular member 50 is disposed on the proximal end side of an indwelling tube 10, an inner tubular member 20 is disposed in the lumen of the indwelling tube 10 and the outer tubular member 50, and the proximal end side of the indwelling tube 10 and the distal end side of the outer tubular member 50 are connected by a filament 60. In this case, depending on how the filament is tensioned, a slight gap is formed between the indwelling tube 10 and the outer tubular member 50. This gap disappears when the outer tubular member 50 presses on the indwelling tube 10 during insertion of the indwelling tube 10. When the proximal sides of the inner tubular member 20 and the outer tubular member 50 are fixed, the inner tubular member 20 advances within the indwelling tube 10 by the gap distance W. Therefore, to prevent the inner tubular member 20 from sinking into the indwelling tube 10, it is preferable that the spatial distance G in the longitudinal direction of the indwelling tube 10 be equal to or greater than the gap distance W. The spatial distance G in the longitudinal direction of the in-vivo indwelling tube 10 is preferably 1 mm or more longer, and more preferably 2 mm or more longer than the gap distance W. From the viewpoint of the rigidity of the medical device 1, the spatial distance G in the longitudinal direction of the in-vivo indwelling tube 10 is preferably 15 mm or less longer than the gap distance W.

[0028] The advancement of the inner tubular member 20 is also related to the radial spatial distance H between the inner diameter of the indwelling tube 10 and the outer diameter of the inner tubular member 20. If the distance H is small, sliding friction occurs between the inner surface of the indwelling tube 10 and the outer surface of the inner tubular member 20 when the indwelling tube 10 is caught at a narrowed portion, preventing the inner tubular member 20 from advancing. On the other hand, if the distance H is large, the inner tubular member 20 is likely to advance even when the indwelling tube 10 is caught at a narrowed portion. However, if the sliding friction between the inner surface of the indwelling tube 10 and the outer surface of the inner tubular member 20 is large, the load required to remove the inner tubular member 20 tends to be high, and if the sliding friction is small, the load required to remove the inner tubular member 20 tends to be low. Therefore, the outer diameter of the inner cylindrical member 20 is preferably 0.75 to 0.98 times the inner diameter of the in-vivo indwelling tube 10, and more preferably 0.80 to 0.95 times the inner diameter.

[0029] 1 , the distal end 20b of the inner tubular member 20 is preferably disposed in a section R from the distal end 10b of the inner tubular member 20 to position r, where r is the position at which the length of the inner tubular member 20 is 50% of the longitudinal length L of the inner tubular member 10. Disposing the inner tubular member 20 in the lumen of the inner tubular member 10 increases the rigidity of the medical device 1, making it easier to insert the inner tubular member 20 into a narrowed or obstructed area in a biological lumen. Therefore, by disposing the distal end 20b of the inner tubular member 20 in section R of the inner tubular member 20, it is possible to ensure the rigidity of the medical device 1 while preventing the inner tubular member 20 from sinking into the inner tubular member 10.

[0030] The minimum inner diameter of the inner diameter of the indwelling tube 10 may be smaller than the maximum outer diameter of the inner tubular member 20 in the section from the distal end 20b of the inner tubular member 20 to a position 40 cm proximal to the distal end 20b. By making the minimum inner diameter of the indwelling tube 10 smaller than the maximum outer diameter of the inner tubular member 20, it is possible to prevent the distal end of the inner tubular member 20 from moving distally from the distal end 10b of the indwelling tube 10.

[0031] 1 , when the outer diameter of the indwelling tube 10 is SD3, the indwelling tube 10 may have a tapered region 15 at the distal end of the indwelling tube 10, where the outer diameter SD3 decreases toward the distal end 10b. By providing the tapered region 15 at the distal end of the indwelling tube 10, the distal end of the indwelling tube 10 can be easily inserted through a narrowed or blocked site in a biological lumen. The location of the tapered region 15 may be, for example, a section from the distal end 10b of the indwelling tube 10 to a position 30 mm longitudinally proximal to the distal end 10b of the indwelling tube 10, a section from the distal end 10b of the indwelling tube 10 to a position 20 mm longitudinally proximal to the distal end 10b of the indwelling tube 10, or a section from the distal end 10b of the indwelling tube 10 to a position 10 mm longitudinally proximal to the distal end 10b of the indwelling tube 10.

[0032] The indwelling tube 10 has a thick-walled portion in the longitudinal direction, and when a portion of the inner tubular member 20 is disposed in the lumen of the indwelling tube 10, the thick-walled portion of the indwelling tube 10 may be disposed distal to the distal end 20b of the inner tubular member 20. This increases the strength of the indwelling tube 10, making it easier to insert the indwelling tube 10 into a narrowed or blocked portion of a biological lumen. The thick-walled portion refers to a region that is thicker than the thickness of the indwelling tube 10 at the inner diameter Sd1 of the indwelling tube 10.

[0033] The thick-walled portion is located in the longitudinal space between the distal end 20b of the inner tubular member 20 and the inner wall of the in-vivo tube 10, and the thick-walled portion is preferably 110% or more, more preferably 120% or more, and even more preferably 130% or more of the thickness of the wall of the in-vivo tube 10 at the position of the inner diameter Sd1 of the in-vivo tube 10. By providing a thick-walled portion in the longitudinal space between the distal end 20b of the inner tubular member 20 and the inner wall of the in-vivo tube 10, the strength of the in-vivo tube 10 can be increased in areas where the inner tubular member 20 is not positioned. The thick-walled portion of the in-vivo tube 10 may be tapered, or may have a step on the inside or outside of the in-vivo tube 10. Furthermore, methods for increasing the strength of the in-vivo indwelling tube 10 in the longitudinal space between the distal end 20b of the inner cylindrical member 20 and the inner wall of the in-vivo indwelling tube 10 include, for example, changing not only the thickness of the in-vivo indwelling tube 10 but also the material, or inserting a reinforcing material into the in-vivo indwelling tube 10. The reinforcing material may be a ring marker.

[0034] Figure 2 is a cross-sectional view showing another embodiment of the medical device according to the present invention. The same reference numerals are used to designate the same components as in Figure 1 to avoid redundant description. The same applies below. The in-vivo indwelling tube 10 of the medical device 1 shown in Figure 2 has a through-hole 16 in the side wall of the in-vivo indwelling tube 10. The in-vivo indwelling tube 10 also has a locking flap 13a on the outer surface of the proximal end of the in-vivo indwelling tube 10, and a locking flap 13b on the outer surface of the distal end. The inner cylindrical member 20 of the medical device 1 shown in Figure 2 has an X-ray opaque marker 17 at the distal end of the inner cylindrical member 20. The inner cylindrical member 20 has a small outer diameter region 25 having an outer diameter smaller than the inner diameter of the proximal end 10a of the indwelling tube 10, and a large outer diameter region 26 located proximal to the small outer diameter region 25 and having an outer diameter larger than the inner diameter of the proximal end 10a of the indwelling tube 10, the small outer diameter region 25 and the large outer diameter region 26 being arranged side by side in the longitudinal direction of the inner cylindrical member 20. The distal end 20c of the large outer diameter region 26 of the inner cylindrical member 20 abuts against the proximal end 10a of the indwelling tube 10, thereby restricting movement of the inner cylindrical member 20 in the longitudinal direction.

[0035] As shown in Figure 2, the indwelling tube 10 may have a through-hole 16 in the side wall of the indwelling tube 10. This allows fluid flowing within a biological lumen to pass from the outside of the indwelling tube 10 through the through-hole 16 into the inside of the indwelling tube 10 and flow from the distal side to the proximal side of the indwelling tube 10, thereby enabling drainage even when the indwelling tube 10 is left in a biological lumen. The position at which the through-hole 16 is disposed in the side wall of the indwelling tube 10 is not particularly limited, and it may be disposed near the center in the longitudinal direction of the indwelling tube 10 as shown in Figure 2, or it may be disposed in the proximal and / or distal portion of the indwelling tube 10.

[0036] The size (circle-equivalent diameter) of the through-hole 16 arranged in the side wall of the in-vivo indwelling tube 10 is, for example, preferably 0.2 mm or more, more preferably 0.3 mm or more, even more preferably 0.5 mm or more, and is preferably 2.0 mm or less, more preferably 1.5 mm or less, and even more preferably 1.3 mm or less. That is, the size (circle-equivalent diameter) of the through-hole 16 arranged in the side wall of the in-vivo indwelling tube 10 is preferably 0.2 mm to 2.0 mm, more preferably 0.3 mm to 1.5 mm, and even more preferably 0.5 mm to 1.3 mm.

[0037] The opening shape of the through-hole 16 provided in the side wall of the in-vivo indwelling tube 10 can be, for example, circular, elliptical, rectangular (e.g., triangular, quadrangular, etc.), etc. From the viewpoint of ease of processing, the opening shape of the through-hole 16 provided in the side wall of the in-vivo indwelling tube 10 is preferably circular or elliptical.

[0038] The number of through holes 16 arranged in the side wall of the in-vivo indwelling tube 10 may be, for example, 1, 2 or more, or 5 or more. The number of through holes 16 arranged in the side wall of the in-vivo indwelling tube 10 is, for example, preferably 25 or less, more preferably 23 or less, and even more preferably 20 or less. That is, the number of through holes 16 arranged in the side wall of the in-vivo indwelling tube 10 may be 1 to 25, 2 to 23, or 5 to 20.

[0039] When the in-vivo tube 10 has a plurality of through-holes 16 in its side wall, the size and opening shape of each through-hole are not particularly limited and may be the same or different. When the in-vivo tube 10 has a plurality of through-holes 16 in its side wall, the arrangement of each through-hole is not particularly limited, and the through-holes may be formed side by side in the longitudinal direction of the in-vivo tube 10, may be formed side by side in the circumferential direction of the in-vivo tube 10, or may be formed side by side in a spiral shape relative to the longitudinal direction of the in-vivo tube 10.

[0040] 2, the indwelling tube 10 may have locking flaps 13a and 13b. By providing the locking flap 13a on the outer surface of the proximal end of the indwelling tube 10, it is possible to prevent, for example, the indwelling tube 10 placed in the bile duct or pancreatic duct from entering the bile duct or pancreatic duct via the duodenal papilla. By providing the locking flap 13b on the outer surface of the distal end of the indwelling tube 10, it is possible to prevent, for example, the indwelling tube 10 placed in the bile duct or pancreatic duct from falling off into the duodenum.

[0041] The in-vivo tube 10 may have a locking flap 13a only on the outer surface of the proximal end of the in-vivo tube 10, or may have a locking flap 13b only on the outer surface of the distal end of the in-vivo tube 10. However, as shown in Figure 2, it is preferable that the in-vivo tube 10 have locking flaps on both the outer surfaces of the proximal end and the distal end.

[0042] The number of locking flaps 13a arranged at the proximal end of the indwelling tube 10 and the number of locking flaps 13b arranged at the distal end of the indwelling tube 10 are not particularly limited, and each may be one, or, for example, two or more, or three or more, and preferably five or less. That is, the number of locking flaps 13a and the number of locking flaps 13b may be one to five, two to five, or three to five, respectively.

[0043] When multiple locking flaps 13a are provided at the proximal end of the indwelling tube 10 or multiple locking flaps 13b are provided at the distal end of the indwelling tube 10, the arrangement of the locking flaps is not particularly limited, but it is preferable that the locking flaps are arranged at equal intervals in the circumferential direction of the indwelling tube 10. This can improve the effect of preventing the indwelling tube 10 from shifting out of position.

[0044] When multiple locking flaps 13a are disposed at the proximal end of the indwelling tube 10 or multiple locking flaps 13b are disposed at the distal end of the indwelling tube 10, the length from the base to the free end of each locking flap and the width and thickness of each locking flap are not particularly limited and may all be the same or different. For example, if each locking flap has the same length, width, and thickness, manufacturing is easier. Furthermore, by varying the length, width, and thickness of each locking flap, the strength of each locking flap can be changed. For example, the strength of locking flaps disposed in areas prone to stress and risk of breakage can be increased, while the strength of locking flaps disposed in areas requiring flexibility can be decreased.

[0045] The method for forming the locking flap is not particularly limited, and the locking flap may be formed at the proximal end and / or distal end of the tube body by, for example, making an incision in the surface of the end of the tube body constituting the in-vivo indwelling tube 10 and causing a part of the tube body to protrude diagonally outward relative to the tube body, or a locking flap member constituting the locking flap may be disposed at the proximal end and / or distal end of the tube body as a member separate from the tube body constituting the in-vivo indwelling tube 10.

[0046] The resin material constituting the in-vivo indwelling tube 10 (i.e., the resin material constituting the tube body, which is the raw material for the in-vivo indwelling tube 10) can be any known resin, including polyamide resins such as nylon; polyether polyamide resins; polyimide resins; polyester resins such as polyethylene terephthalate (PET); polyurethane resins; polyolefin resins such as polyethylene and polypropylene; fluorine-based resins such as polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), and ethylene tetrafluoroethylene copolymer (ETFE); polyvinyl chloride resins; silicone resins; and natural rubber. These resins may be used alone or in combination. Among these, polyamide resins, polyurethane resins, polyolefin resins, and fluorine-based resins are preferred. By including at least one of polyamide resins, polyurethane resins, polyolefin resins, and fluorine-based resins in the in-vivo indwelling tube 10, both biocompatibility and flexibility of the in-vivo indwelling tube 10 can be achieved.

[0047] The layer structure in the thickness direction of the in-vivo indwelling tube 10 is not particularly limited and may be a single-layer structure or a multi-layer structure, but a single-layer structure is preferred. A single-layer structure allows for easy manufacturing. In the case of a multi-layer structure, the type of resin material constituting each layer is not particularly limited and may be the same or different.

[0048] The in-vivo indwelling tube 10 may be composed of a single tube from the proximal end 10a to the distal end 10b of the in-vivo indwelling tube 10, or may be composed of multiple tubes lined up in the longitudinal direction and joined together.

[0049] When the locking flap member is bonded to the outer surface of the tube body to form the locking flap, the material of the locking flap member is not particularly limited and may be the same as or different from the material of the tube body, but is preferably the same as the material of the tube body, which increases the bonding strength of the locking flap member to the tube body.

[0050] The tube body and the locking flap member can be joined by, for example, heat welding, ultrasonic welding, or adhesive bonding, with heat welding being preferred. By joining the tube body and the locking flap member by heat welding, the joining strength between the tube body and the locking flap member can be increased.

[0051] The locking flaps are preferably formed by cutting into the surface of the end of the tube body, which makes them less likely to fall off than locking flaps formed by joining locking flap members to the outer surface of the tube body.

[0052] The locking flap 13a arranged at the proximal end of the indwelling tube 10 and the locking flap 13b arranged at the distal end of the indwelling tube 10 may be formed by the same method or by different methods.

[0053] As shown in FIG. 2 , the inner cylindrical member 20 may have a radiopaque marker 17 at the distal end of the inner cylindrical member 20. By having the radiopaque marker 17, the position of the inner cylindrical member 20 can be confirmed under X-ray fluoroscopy. When the radiopaque marker 17 is disposed at the distal end of the inner cylindrical member 20, the number of radiopaque markers 17 is not particularly limited, and may be one, two or more, or three or more. In FIG. 2 , one radiopaque marker 17 is provided at the distal end of the inner cylindrical member 20. The shape of the radiopaque marker 17 is not particularly limited, and examples thereof include a tubular shape (e.g., a cylindrical shape, a polygonal tubular shape, etc.), a tubular shape with a C-shaped cross section, and a coil shape formed by winding a wire. Among these, a tubular shape is preferred. The radiopaque marker 17 can be made of known materials, such as radiopaque materials such as lead, barium, iodine, tungsten, gold, platinum, iridium, stainless steel, titanium, and cobalt-chromium alloy.

[0054] 2 , the inner tubular member 20 may have a small outer diameter region 25 having an outer diameter smaller than the inner diameter of the proximal end 10 a of the indwelling tube 10, and a large outer diameter region 26 proximal to the small outer diameter region 25 and having an outer diameter larger than the inner diameter of the proximal end 10 a of the indwelling tube 10, and the small outer diameter region 25 and the large outer diameter region 26 may be arranged side by side in the longitudinal direction of the inner tubular member 20. In this way, when the inner tubular member 20 is inserted into the lumen of the indwelling tube 10, the small outer diameter region 25 of the inner tubular member 20 is arranged in the lumen of the indwelling tube 10. On the other hand, the distal end 20 c of the large outer diameter region 26 of the inner tubular member 20 abuts against the proximal end 10 a of the indwelling tube 10, and therefore the large outer diameter region 26 of the inner tubular member 20 is not arranged in the lumen of the indwelling tube 10. In this case, the inner cylindrical member 20 serves as the outer cylindrical member 50 described below, and can also serve as a pusher member for the indwelling tube 10. Furthermore, by adjusting the length of the small outer diameter region 25 of the inner cylindrical member 20 and the length of the indwelling tube 10 into which the small outer diameter region 25 can be inserted, a space can be formed between the distal end 20b of the inner cylindrical member 20 and the inner wall of the indwelling tube 10 in the longitudinal direction of the indwelling tube 10.

[0055] Fig. 3 is a cross-sectional view showing another embodiment of the medical device according to the present invention. The in-vivo indwelling tube 10 of the medical device 1 shown in Fig. 3 has a tapered region 18 at the distal end of the in-vivo indwelling tube 10, the inner diameter of which decreases toward the distal end.

[0056] 3, when the inner diameter of the indwelling tube 10 is Sd4, the indwelling tube 10 may have a tapered region 18 at the distal end of the indwelling tube 10, where the inner diameter Sd4 decreases toward the distal end 10b. By providing the tapered region 18 at the distal end of the indwelling tube 10, it is possible to provide a strength gradient at the distal end of the indwelling tube 10.

[0057] The position where the reduced diameter region 18 of the indwelling tube 10 is formed is preferably the distal end of the indwelling tube 10, and is preferably, for example, a section from the distal end 10b of the indwelling tube 10 to a position 30 mm longitudinally proximally from the distal end 10b of the indwelling tube 10, a section from the distal end 10b of the indwelling tube 10 to a position 20 mm longitudinally proximally, or a section from the distal end 10b of the indwelling tube 10 to a position 10 mm longitudinally proximally from the distal end 10b of the indwelling tube 10. The distal end of the reduced diameter region 18 of the in-vivo tube 10 in the longitudinal direction may be proximal to a position 3 mm longitudinally proximal to the distal end 10 b of the in-vivo tube 10, or may be proximal to a position 5 mm longitudinally proximally to the distal end 10 b of the in-vivo tube 10, or may be proximal to a position 8 mm longitudinally proximally to the distal end 10 b of the in-vivo tube 10.

[0058] Fig. 4 is a cross-sectional view showing another embodiment of the medical device according to the present invention. The indwelling tube 10 of the medical device 1 shown in Fig. 4 has a tapered region 18 at the distal end of the indwelling tube 10, where the inner diameter decreases toward the distal end 10b of the indwelling tube 10, and the tapered region 18 extends to the distal end 10b of the indwelling tube 10.

[0059] 4, the inner diameter Sd4 of the indwelling tube 10 may be smallest at the distal end 10b of the indwelling tube 10. That is, the distal end of the reduced diameter region 18 in the longitudinal direction of the indwelling tube 10 may coincide with the distal end 10b of the indwelling tube 10. This reduces the rigidity of the distal end of the indwelling tube 10, making it less likely to damage the wall of a lumen in the body.

[0060] Fig. 5 is a cross-sectional view showing another embodiment of the medical device according to the present invention. The indwelling tube 10 of the medical device 1 shown in Fig. 5 has a through-hole 16 in the distal portion of the indwelling tube 10, which communicates between the outside and the inside, and X-ray opaque markers 17 are arranged on the distal and proximal sides of the locking flaps 13a and 13b.

[0061] 5, the indwelling tube 10 may have a through-hole 16 in the distal portion of the indwelling tube 10. This allows fluid flowing within a biological lumen to pass through the through-hole 16, enter from the outside to the inside of the indwelling tube 10, and flow from the distal side to the proximal side of the indwelling tube 10, making drainage possible even when the indwelling tube 10 is left in the biological lumen.

[0062] When a through-hole 16 is formed in the distal portion of the indwelling tube 10, the through-hole 16 may extend in the radial direction of the indwelling tube 10, or as shown in Fig. 5 , may extend obliquely relative to the radial direction of the indwelling tube 10 so that a fluid flows from the distal side on the outside to the proximal side on the inside of the indwelling tube 10, and preferably extends so that a fluid flows from the distal side on the outside to the proximal side on the inside of the indwelling tube 10. By having the through-hole 16 disposed in the distal portion of the indwelling tube 10 extend from the distal side to the proximal side of the indwelling tube 10, the fluid flowing within the biological lumen can easily flow from the distal side to the proximal side of the indwelling tube 10.

[0063] The size (circle-equivalent diameter) of the through-hole 16 disposed in the distal portion of the in-vivo indwelling tube 10 is not particularly limited, but is, for example, preferably 0.2 mm or more, more preferably 0.3 mm or more, even more preferably 0.5 mm or more, and is preferably 1.5 mm or less, more preferably 1.3 mm or less, and even more preferably 1.0 mm or less. That is, the size (circle-equivalent diameter) of the through-hole 16 disposed in the distal portion of the in-vivo indwelling tube 10 is preferably 0.2 to 1.5 mm, more preferably 0.3 to 1.3 mm, and even more preferably 0.5 to 1.0 mm.

[0064] The opening shape of the through-hole 16 provided in the distal portion of the in-vivo indwelling tube 10 is not particularly limited, and examples thereof include a circle, an ellipse, a rectangle (e.g., a triangle, a square, etc.), etc. From the viewpoint of ease of processing, the opening shape of the through-hole 16 provided in the distal portion of the in-vivo indwelling tube 10 is preferably a circle or an ellipse.

[0065] The number of through-holes 16 arranged in the distal portion of the in-vivo indwelling tube 10 is not particularly limited and may be, for example, 1 or 2 or more. The upper limit of the number of through-holes 16 arranged in the distal portion of the in-vivo indwelling tube 10 is also not particularly limited, but is, for example, preferably 6 or less, more preferably 5 or less, and even more preferably 4 or less. That is, the number of through-holes 16 arranged in the distal portion of the in-vivo indwelling tube 10 may be 1 to 6, 2 to 5, or 2 to 4.

[0066] When the in-vivo tube 10 has a plurality of through-holes 16 in the distal portion, the size and opening shape of each through-hole are not particularly limited and may be the same or different. When the in-vivo tube 10 has a plurality of through-holes 16 in the distal portion, the arrangement of each through-hole is not particularly limited and may be formed in a row in the longitudinal direction of the in-vivo tube 10, may be formed in a row in the circumferential direction of the in-vivo tube 10, or may be formed in a row in a spiral shape relative to the longitudinal direction of the in-vivo tube 10.

[0067] 5, the indwelling tube 10 may have a radiopaque marker 17. By having the radiopaque marker 17, the position of the indwelling tube 10 can be confirmed under X-ray fluoroscopy.

[0068] The location of the radiopaque marker 17 is not particularly limited, but is preferably the distal portion of the indwelling tube 10, more preferably distal to the locking flap presence region in the distal portion of the indwelling tube 10 and / or proximal to the locking flap presence region in the distal portion of the indwelling tube 10, and even more preferably both distal to the locking flap presence region in the distal portion of the indwelling tube 10 and proximal to the locking flap presence region in the distal portion of the indwelling tube 10. The locking flap presence region refers to the region where the locking flap is formed, and refers to the section from the base of the locking flap to the free end.

[0069] The radiopaque marker 17 may also be disposed in the proximal portion of the indwelling tube 10, more preferably distal to the locking flap region in the proximal portion of the indwelling tube 10 and / or proximal to the locking flap region in the proximal portion of the indwelling tube 10, and even more preferably both distal to the locking flap region in the proximal portion of the indwelling tube 10 and proximal to the locking flap region in the proximal portion of the indwelling tube 10. The proximal portion of the indwelling tube 10 refers, for example, to the region from the proximal end 10a of the indwelling tube 10 to a position that is 50% of the longitudinal length L of the indwelling tube 10. The distal portion of the indwelling tube 10 refers, for example, to the region from the distal end 10b of the indwelling tube 10 to a position that is 50% of the longitudinal length L of the indwelling tube 10.

[0070] The number of radiopaque markers 17 is not particularly limited and may be one, two or more, or three or more. In Fig. 5, one radiopaque marker is provided distally of the region where the locking flap is present in the distal portion of the indwelling tube 10, and one radiopaque marker is provided proximally, and one radiopaque marker is provided distally of the region where the locking flap is present in the proximal portion of the indwelling tube 10, and one radiopaque marker is provided proximally.

[0071] For the shape of the radiopaque marker 17 placed on the in-vivo indwelling tube 10 and the material that constitutes the radiopaque marker 17 placed on the in-vivo indwelling tube 10, please refer to the description of the shape of the radiopaque marker 17 placed on the distal end of the inner tube member 20 and the material that constitutes the radiopaque marker 17 placed on the distal end of the inner tube member 20.

[0072] Figure 6 is a cross-sectional view showing another embodiment of the medical device according to the present invention, showing an enlarged view of the distal end of the indwelling tube 10 and the inner cylindrical member 20. As shown in Figure 6, when the outer diameter of the inner cylindrical member 20 is CD2, the inner cylindrical member 20 may have an expanding outer diameter region 22 at the distal end of the inner cylindrical member 20, in which the outer diameter CD2 increases toward the distal end 20b. This makes it easier for the distal end of the inner cylindrical member 20 to abut against the lumen wall of the indwelling tube 10, thereby reducing the misalignment between the axial center of the indwelling tube 10 and the axial center of the inner cylindrical member 20. As a result, the guidewire 9 inserted from the distal end 10b of the indwelling tube 10 can be easily inserted from the distal end 20b of the inner cylindrical member 20.

[0073] The position at which the outer diameter expansion region 22 is formed is preferably, for example, a section from the distal end 20b of the inner tube member 20 to a position 60 mm longitudinally away from the distal end 20b of the inner tube member 20 proximally, a section from the distal end 20b of the inner tube member 20 to a position 50 mm longitudinally away from the distal end 20b of the inner tube member 20 proximally, or a section from the distal end 20b of the inner tube member 20 to a position 40 mm longitudinally away from the distal end 20b of the inner tube member 20 proximally.

[0074] 7 is a cross-sectional view showing another embodiment of the medical device according to the present invention, showing an enlarged view of the in-vivo indwelling tube 10 and the distal end of the inner cylindrical member 20. As shown in Fig. 7, when the inner diameter at the distal end of the inner cylindrical member 20 is Cd1, the inner cylindrical member 20 may have an expanding inner diameter region 23 at the distal end of the inner cylindrical member 20, in which the inner diameter Cd1 increases toward the distal end 20b. This enlarges the opening at the distal end 20b of the inner cylindrical member 20, making it easier to insert the guidewire 9 inserted from the distal end 10b of the in-vivo indwelling tube 10 through the opening at the distal end 20b of the inner cylindrical member 20.

[0075] When the inner cylindrical member 20 has the expanding inner diameter region 23, it is preferable that the outer diameter of the inner cylindrical member 20 at the expanding inner diameter region 23 of the inner cylindrical member 20 increases toward the distal end 20b of the inner cylindrical member 20, as shown in Fig. 7. That is, as shown in Fig. 7, the outer diameter of the inner cylindrical member 20 at the expanding inner diameter region 23 may form an expanding outer diameter region.

[0076] The position where the inner diameter expansion region 23 is formed is not particularly limited, but it is preferable that it be, for example, a section from the distal end 20b of the inner tube member 20 to a position 60 mm longitudinally away from the distal end 20b of the inner tube member 20 proximally, a section from the distal end 20b of the inner tube member 20 to a position 50 mm longitudinally away from the distal end 20b of the inner tube member 20 proximally, or a section from the distal end 20b of the inner tube member 20 to a position 40 mm longitudinally away from the distal end 20b of the inner tube member 20 proximally.

[0077] From the viewpoint of ease of guidewire insertion, the inner diameter of the distal end of the inner cylindrical member 20 is preferably larger than the inner diameter Sd2 of the indwelling tube 10 located distal to the inner cylindrical member 20, and is more preferably 105% or more of the inner diameter Sd2, even more preferably 110% or more of the inner diameter Sd2, and particularly preferably 115% or more of the inner diameter Sd2. This makes it easy to insert the guidewire even if the inner diameter of the inner cylindrical member 20 at the distal end of the inner cylindrical member 20 is not expanded.

[0078] Figure 8 is a cross-sectional view showing another embodiment of the medical device according to the present invention, showing an enlarged view of the in-vivo indwelling tube 10 and the distal end of the inner cylindrical member 20. As shown in Figure 8, the inner cylindrical member 20 may have a taper 24 at the distal end of the inner cylindrical member 20, in which the outer diameter decreases toward the distal end 20b. This makes it less likely that the distal end 20b of the inner cylindrical member 20 will get caught even if it comes into contact with the inner wall of the in-vivo indwelling tube 10, thereby reducing the pull-out load of the inner cylindrical member 20 and improving operability for the operator.

[0079] Figure 9 is a cross-sectional view showing another embodiment of the medical device according to the present invention. The medical device 1 shown in Figure 9 includes an indwelling tube 10 and an inner tubular member 20, with a portion of the inner tubular member 20 disposed within the lumen of the indwelling tube 10. The indwelling tube 10 has an arcuate portion A that is curved in an arc shape, and a non-arcuate portion B located proximal to the arcuate portion A. Whether the indwelling tube 10 belongs to the arcuate portion A or the non-arcuate portion B is determined by the following method.

[0080] 10 , a point to be determined on the central axis 11 of the indwelling tube 10 in a planar view is designated as point a, a point 2.5 mm away from point a along the central axis 11 in the proximal direction of the indwelling tube 10 is designated as point b, and a point 5 mm away from point a along the central axis 11 in the proximal direction of the indwelling tube 10 is designated as point c. An imaginary circle 12 passing through points a, b, and c is created, and a line segment connecting point a and the center o of the imaginary circle 12 is designated as line segment ao. If a point on the virtual circle 12 that is closer to the proximal end 10a of the indwelling tube 10 than point a is designated as point x and the central angle with respect to the arc ax is 45°, then if the indwelling tube 10 intersects with the line segment ox, point a is determined to belong to the arc portion A of the indwelling tube 10, whereas if the indwelling tube 10 does not intersect with the line segment ox, point a is determined to belong to the non-arc portion B of the indwelling tube 10. When the indwelling tube 10 intersects with the line segment ox, this means that a part of the indwelling tube 10 intersects with the line segment ox, as shown in Figure 10, or the entire indwelling tube 10 intersects with the line segment ox, as shown in Figure 11. When the indwelling tube 10 does not intersect with the line segment ox, this means that the indwelling tube 10 and the line segment ox are separated from each other and do not intersect, as shown in Figure 12.

[0081] The position at which the inner tubular member 20 is disposed inside the indwelling tube 10 is not particularly limited, but it is preferable that the inner tubular member 20 be disposed in at least a part of the non-circular portion B of the indwelling tube 10, and not in the circular portion A of the indwelling tube 10. This reduces the pull-out load of the inner tubular member 20 when placing the indwelling tube 10 in the affected area, improving operability for the operator and facilitating positioning of the indwelling tube 10. When the indwelling tube 10 is, for example, straight, friction between the indwelling tube 10 and the inner tubular member 20 is small, and therefore the pull-out load of the inner tubular member 20 when placing the indwelling tube 10 in the affected area can be reduced.

[0082] Figure 13 is a cross-sectional view showing another embodiment of the medical device according to the present invention. The medical device 1 shown in Figure 13 includes an indwelling tube 10 and an inner cylindrical member 20. The indwelling tube 10 has a locking flap 13a on the outer surface of the proximal end of the indwelling tube 10. The indwelling tube 10 also has an arcuate portion A that is curved in an arc shape and a non-arcuate portion B that is located proximally of the arcuate portion A. The arcuate portion A has a closed ring shape in a plan view. This prevents the indwelling tube 10, for example, placed in the bile duct or pancreatic duct from falling out of the bile duct or pancreatic duct into the duodenum.

[0083] By providing an engagement flap 13a on the outer surface of the proximal end of the in-vivo indwelling tube 10, it is possible to prevent the in-vivo indwelling tube 10, when placed in the bile duct or pancreatic duct, from entering the bile duct or pancreatic duct through the duodenal papilla, for example.

[0084] When the in-vivo tube 10 has the arc portion A, it may have a locking flap distal to the arc portion A, and the locking flap may be disposed on the outer surface of the distal end of the in-vivo tube 10.

[0085] Fig. 14 is a cross-sectional view showing another embodiment of the medical device according to the present invention. The medical device 1 shown in Fig. 14 includes an indwelling tube 10 and an inner cylindrical member 20. The indwelling tube 10 has an arcuate portion A curved in an arc shape, a non-arcuate portion B proximal to the arcuate portion A, and a proximal arcuate portion D proximal to the arcuate portion A. The arcuate portion A and the proximal arcuate portion D are configured in the shape of a closed ring in a plan view.

[0086] By disposing the inner tube member 20 in the lumen of the proximal arc portion D, pushability can be improved. When the indwelling tube 10 is placed in a living body, the proximal arc portion D of the indwelling tube 10 may be disposed closer to the duodenum than the duodenal papilla. This prevents the placement load from becoming large even when the inner tube member 20 is disposed in the lumen of the proximal arc portion D. By configuring the arc portion A of the indwelling tube 10 as a closed ring in plan view, it is possible to prevent, for example, the indwelling tube 10 placed in the bile duct or pancreatic duct from falling out of the bile duct or pancreatic duct into the duodenum. By configuring the proximal arc portion D of the indwelling tube 10 as a closed ring in plan view, it is possible to prevent, for example, the indwelling tube 10 placed in the bile duct or pancreatic duct from entering the bile duct or pancreatic duct via the duodenal papilla.

[0087] The medical device 1 may further include an outer tubular member 50 having a longitudinal direction, and the outer tubular member 50 may be disposed outside the inner tubular member 20 proximal to the proximal end 10a of the indwelling tube 10. In this case, the outer tubular member 50 is preferably configured to be movable in the longitudinal direction of the inner tubular member 20.

[0088] The outer tubular member 50 and the inner tubular member 20 may be fixed on the proximal side. This can restrict the inner tubular member 20 from moving distally in the longitudinal direction within the lumen of the indwelling tube 10. When the outer tubular member 50 is fixed on the proximal side, for example, the proximal end of the outer tubular member 50 may be fixed to a handle or the like. The method for fixing the proximal end of the outer tubular member 50 to a handle or the like is not particularly limited. For example, a connection mechanism such as a luer lock, a coupler, or other fitting mechanism may be provided on the handle body, and the proximal end of the outer tubular member 50 may be fixed to the handle body via this connection mechanism.

[0089] Figure 15 is a cross-sectional view showing another embodiment of a medical device according to the present invention. The medical device 1 shown in Figure 15 further includes an outer tubular member 50 having a longitudinal direction, and a filament 60. In Figure 15, the portion of the filament 60 located on the front side of the paper is shown by a dashed line to make it easier to understand the positional relationship between the filament 60 and the inner tubular member 20.

[0090] 15 , the outer tubular member 50 may be disposed proximal to the proximal end 10 a of the indwelling tube 10 and outside the inner tubular member 20. In this case, the outer tubular member 50 is preferably configured to be movable in the longitudinal direction of the inner tubular member 20.

[0091] The outer tube member 50 may have a through-hole 72 in the side wall of the distal portion of the outer tube member 50. The distal portion of the outer tube member 50 refers to the region from the distal end of the outer tube member 50 to a position 60 mm away in the longitudinal direction on the proximal side from the distal end of the outer tube member 50. The in-vivo indwelling tube 10 may have a through-hole 71 in the side wall of the proximal portion of the in-vivo indwelling tube 10.

[0092] The thread 60 is configured as a closed ring that passes through the through-hole 72 of the outer tubular member 50, and a portion 51 of the distal end of the outer tubular member 50 distal to the through-hole 72 of the outer tubular member 50 is disposed within the ring. The ring of the thread 60 is passed through the through-hole 71 of the indwelling tube 10, and the inner tubular member 20 may be disposed within the ring. In this case, a portion 14 of the proximal end of the indwelling tube 10 is not disposed within the ring of the thread 60. The indwelling tube 10 and the outer tubular member 50 are connected by disposing the inner tubular member 20 within the ring formed by the thread 60. This allows force applied from the proximal side to be easily transmitted through the outer tubular member 50 to facilitate the operation of pushing the indwelling tube 10 distally and transporting the indwelling tube 10 to the affected area. Furthermore, even after the indwelling tube 10 has been delivered to the affected area, the indwelling tube 10 can be moved proximally by pulling the inner tubular member 20 and the outer tubular member 50 proximally, facilitating positioning of the indwelling tube 10 when it is placed. Furthermore, the thread 60 is inserted into the through-hole 72 of the outer tubular member 50, and the loop of the thread 60 is inserted into the through-hole 71 of the indwelling tube 10, which facilitates connection of the indwelling tube 10 and the outer tubular member 50 with the thread 60. Furthermore, because the thread 60 is configured as a closed loop and the inner tubular member 20 is positioned inside the loop, the connection between the indwelling tube 10 and the outer tubular member 50 can be easily released by removing the inner tubular member 20 from the loop. This facilitates placement of the indwelling tube 10 at the affected area.

[0093] The diameter (wire diameter) of the thread body 60 may be, for example, 0.05 mm to 0.8 mm, or 0.05 mm to 0.5 mm. The thread body 60 may be a solid wire or a twisted wire.

[0094] For example, a suture may be used as the thread body 60. When the thread body 60 is a suture, the thread body 60 can be made flexible while maintaining its durability, and therefore the thread body 60 can be made less likely to damage the in-vivo indwelling tube 10, the wall of a lumen in the body, or the like.

[0095] The material constituting the thread body 60 is not particularly limited, and examples thereof include natural fibers, metals, and resins, with resins being preferred. Examples of natural fibers include cotton, linen, silk, and wool. Examples of metals include gold, platinum, and titanium. Examples of resins include polyamide-based resins such as nylon; polyether polyamide-based resins; polyimide-based resins; polyester-based resins such as polyethylene terephthalate (PET); polyurethane-based resins; polyolefin-based resins such as polyethylene and polypropylene; fluorine-based resins such as polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), and ethylene tetrafluoroethylene copolymer (ETFE); polyvinyl chloride-based resins; silicone-based resins; and natural rubber. These materials may be used alone or in combination. Among these, polyamide-based resins, polyester-based resins, polyurethane-based resins, polyolefin-based resins, and fluorine-based resins are preferred.

[0096] The in-vivo indwelling tube 10 included in the medical device 1 according to the embodiment of the present invention may be used as a plastic tube stent to be placed in the bile duct or pancreatic duct, for example.

[0097] When the indwelling tube 10 is placed in the bile duct, the side of the indwelling tube 10 that is placed on the duodenum side is defined as the proximal side, and the opposite side (gallbladder side or liver side) is defined as the distal side, and the distal end 10b of the indwelling tube 10 may be placed on the gallbladder side or the liver side. When the distal end 10b of the indwelling tube 10 is placed on the liver side, a portion of the distal end of the indwelling tube 10 may be placed in the hepatic duct.

[0098] The longitudinal length L of the in-vivo indwelling tube 10 is not particularly limited, but may be, for example, 30 mm to 400 mm. The maximum outer diameter of the in-vivo indwelling tube 10 is not particularly limited, but may be, for example, 5 French to 11 French (approximately 1.7 mm to approximately 3.7 mm).

[0099] Known resins can be used as the resin material constituting the inner tube member 20, including, for example, polyamide resins such as nylon; polyether polyamide resins; polyimide resins; polyester resins such as polyethylene terephthalate (PET); polyurethane resins; polyolefin resins such as polyethylene and polypropylene; fluorine-based resins such as polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), and ethylene tetrafluoroethylene copolymer (ETFE); polyvinyl chloride resins; silicone resins; and natural rubber. These may be used alone or in combination of two or more. Among these, polyamide resins, polyester resins, polyurethane resins, polyolefin resins, and fluorine-based resins are preferred.

[0100] The structure of the inner tube member 20 may be a single-layer structure or a multi-layer structure, but a single-layer structure is preferable. A single-layer structure makes it easy to manufacture. In the case of a multi-layer structure, the resin materials constituting each layer may be the same or different.

[0101] The inner cylindrical member 20 may be formed from a single tube extending from the proximal end 20a to the distal end 20b of the inner cylindrical member 20, or may be formed by joining multiple tubes arranged in the longitudinal direction. By forming the inner cylindrical member 20 from multiple tubes, the bending rigidity of the inner cylindrical member 20 can be varied along the longitudinal direction. For example, by making the hardness of the material of the tube constituting the distal portion of the inner cylindrical member 20 lower than that of the material of the tube constituting the proximal portion of the inner cylindrical member 20, the inner cylindrical member 20 can have low bending rigidity in the distal portion and high bending rigidity in the proximal portion. The low bending rigidity of the distal portion of the inner cylindrical member 20 can improve the followability of the guidewire 9. The high bending rigidity of the proximal portion of the inner cylindrical member 20 can improve pushability. The distal portion of the inner cylindrical member 20 refers to, for example, the region from the distal end 20b of the inner cylindrical member 20 to a position that is 50% of the longitudinal length of the inner cylindrical member 20. The proximal portion of the inner cylindrical member 20 refers to, for example, a region from the proximal end 20 a of the inner cylindrical member 20 to a position that is 50% of the longitudinal length of the inner cylindrical member 20 .

[0102] Known resins can be used as the resin material constituting the outer tube member 50, including, for example, polyamide resins such as nylon; polyether polyamide resins; polyimide resins; polyester resins such as polyethylene terephthalate (PET); polyurethane resins; polyolefin resins such as polyethylene and polypropylene; fluorine-based resins such as polytetrafluoroethylene (PTFE), perfluoroalkoxyalkane (PFA), and ethylene tetrafluoroethylene copolymer (ETFE); polyvinyl chloride resins; silicone resins; and natural rubber. These may be used alone or in combination of two or more. Among these, polyamide resins, polyester resins, polyurethane resins, polyolefin resins, and fluorine-based resins are preferred.

[0103] The outer tube member 50 may have a single-layer structure or a multi-layer structure, but a single-layer structure is preferable. A single-layer structure allows for easy manufacturing. In the case of a multi-layer structure, the resin materials constituting each layer may be the same or different.

[0104] The outer tubular member 50 may be constructed from a single tube extending from the proximal end to the distal end of the outer tubular member 50, or may be constructed by joining multiple tubes aligned in the longitudinal direction. By constructing the outer tubular member 50 from multiple tubes, the bending rigidity of the outer tubular member 50 can be varied along the longitudinal direction. For example, by making the hardness of the material of the tube constituting the distal portion of the outer tubular member 50 lower than the hardness of the material of the tube constituting the proximal portion of the outer tubular member 50, the outer tubular member 50 can have low bending rigidity in the distal portion and high bending rigidity in the proximal portion. The low bending rigidity of the distal portion of the outer tubular member 50 can improve the followability of the outer tubular member 50 to the guidewire. The distal portion of the outer tubular member 50 refers to, for example, the region from the distal end of the outer tubular member 50 to a position that is 50% of the longitudinal length of the outer tubular member 50. The proximal portion of the outer tubular member 50 refers to, for example, the region from the proximal end of the outer tubular member 50 to a position that is 50% of the longitudinal length of the outer tubular member 50.

[0105] The resin material constituting the outer cylindrical member 50 and the resin material constituting the inner cylindrical member 20 may be the same or different.

[0106] The maximum outer diameter of the outer tube member 50 is not particularly limited as long as it is large enough to push the in-vivo indwelling tube 10 from the proximal side to the distal side, and may be larger, the same as, or smaller than the maximum outer diameter of the in-vivo indwelling tube 10, but it is more preferable that it be the same as the maximum outer diameter of the in-vivo indwelling tube 10.

[0107] This application claims the benefit of priority based on Japanese Patent Application No. 2024-002406, filed on January 11, 2024. The entire contents of the specification of Japanese Patent Application No. 2024-002406 are incorporated herein by reference.

[0108] REFERENCE SIGNS LIST 1 Medical device 9 Guide wire 10 In-vivo indwelling tube 10a Proximal end of in-vivo indwelling tube 10b Distal end of in-vivo indwelling tube 11 Central axis 12 Virtual circle 13a, 13b Locking flap 14 Part of proximal end of inner tubular member 15 Diameter-reducing region in which outer diameter SD3 decreases toward the distal end 16 Through hole 17 Radiopaque marker 18 Diameter-reducing region of inner diameter of in-vivo indwelling tube 10 20 Inner tubular member 20a Proximal end of inner tubular member 20b Distal end of inner tubular member 20c Distal end of large outer diameter region of inner tubular member 22 Outer diameter expanding region 23 Inner diameter expanding region 24 Taper 25 Small outer diameter region of inner tubular member 26 Large outer diameter region of inner tubular member 50 Outer tubular member 51 a: A part of the distal end of the outer tubular member that is distal to the through-hole of the outer tubular member 60: Filament 71, 72: Through-hole CD1: Maximum outer diameter at the distal end of the inner tubular member CD2: Outer diameter of the inner tubular member Cd1: Inner diameter of the inner tubular member SD3: Outer diameter of the tube that is left in vivo Sd1: Inner diameter of the tube that is left in vivo Sd2: Inner diameter of the tube that is left in vivo a, b, c: Point on the central axis of the tube that is left in vivo o: Center of the imaginary circle x: Point on the imaginary circle r: Position where the length is 50% of the longitudinal length of the tube that is left in vivo A: Arc portion B: Non-arc portion D: Proximal arc portion G: Spatial distance in the longitudinal direction of the tube that is left in vivo H: Spatial distance in the radial direction between the inner diameter of the tube that is left in vivo and the outer diameter of the inner tubular member L: Length in the longitudinal direction of the tube that is left in vivo R Section W from the distal end of the indwelling tube to position r: Gap distance in the longitudinal direction of the indwelling tube

Claims

1. A medical device comprising a body-implantable tube having a longitudinal direction and a proximal end and a distal end, and an inner tube member disposed in the lumen of the body-implantable tube and having a longitudinal direction and a proximal end and a distal end, wherein the body-implantable tube has at least an inner diameter Sd1 and an inner diameter Sd2 smaller than the inner diameter Sd1, and the position of the inner diameter Sd2 in the longitudinal direction is on the distal side of the position of the inner diameter Sd1, and the inner tube member is movable in the longitudinal direction in the lumen of the body-implantable tube, but the distal end of the inner tube member cannot move further distally than the distal end of the body-implantable tube.

2. The medical device according to claim 1, wherein the distal end of the inner tube member is disposed in a section from the distal end of the body-implantable tube to a position where the length is 50% of the longitudinal length of the body-implantable tube.

3. The medical device according to claim 1, wherein there is a space in the longitudinal direction between the distal end of the inner tube member and the inner wall of the body-implantable tube.

4. The medical device according to claim 3, wherein the inner diameter of the body-implantable tube in the space is larger than the outer diameter of the distal end of the inner tube member.

5. The medical device according to claim 1, wherein the distal movement of the inner tube member in the longitudinal direction in the lumen of the body-implantable tube is restricted.

6. The medical device further comprises an outer tube member having a longitudinal direction, the outer tube member is disposed outside the inner tube member on the proximal side of the proximal end of the body-implantable tube, and the outer tube member and the inner tube member are fixed on the proximal side.

7. The medical device according to claim 1, wherein the minimum inner diameter of the body-implantable tube is smaller than the maximum outer diameter of the inner tube member in a section from the distal end of the inner tube member to a position 40 cm proximal to the distal end.

8. The medical device according to claim 1, wherein the body-implantable tube has a thick-walled portion in the longitudinal direction, and the thick-walled portion is disposed on the distal side of the distal end of the inner tube member.

9. The medical device according to claim 1, wherein the body-implantable tube is a plastic tube stent to be implanted in the bile duct or pancreatic duct.

10. The medical device according to claim 1, wherein the body-implantable tube has an arcuate portion curved in an arc shape and a non-arcuate portion on the proximal side of the arcuate portion.

11. The medical instrument according to claim 10, wherein the arc portion of the in-vivo indwelling tube is configured in a closed annular shape in a plan view.

12. The medical instrument according to claim 1, wherein the distal end of the inner tube member cannot move distally beyond the distal end of the in-vivo indwelling tube.

13. The medical instrument further includes an outer tube member having a longitudinal direction and a cord body. The outer tube member is disposed outside the inner tube member proximal to the proximal end of the in-vivo indwelling tube and is movable in the longitudinal direction of the inner tube member. The outer tube member has a through-hole in the side wall of the distal portion of the outer tube member. The in-vivo indwelling tube has a through-hole in the side wall of the proximal portion of the in-vivo indwelling tube. The cord body is configured as a closed loop passing through the through-hole of the outer tube member, and a part of the distal end portion of the outer tube member distal to the through-hole of the outer tube member is disposed within the loop. The loop of the cord body is passed through the through-hole of the in-vivo indwelling tube, and the inner tube member is disposed within the loop. The medical instrument according to claim 1.

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