WO2025150326A1 - Medical instrument - Google Patents

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

The present invention relates to a medical device that includes an in-vivo indwelling tube.

Body lumens such as blood vessels or digestive tracts such as the bile duct or pancreatic duct may become narrowed or blocked due to various causes. As a method for treating various diseases caused by narrowing or blocking, a method is known in which a tube-shaped stent is placed at the narrowed or blocked area to expand the narrowed or blocked area from the inside and widen the body lumen. For example, when narrowing or blocking occurs in the bile duct, a bile duct tube stent is delivered to the narrowed or blocked area. The tube stent delivered to the narrowed or blocked area is placed and pushes open the narrowed or blocked area from the inside. By placing the stent, the inner diameter of the bile duct at the narrowed or blocked area is expanded, and the narrowing or blocking is improved. As a result, bile can be discharged from the bile duct to the duodenum, and various diseases caused by narrowing or blocking of the bile duct, such as biliary atresia, jaundice, and biliary cancer, can be treated. Medical devices having such tube stents are described, for example, in Patent Documents 1 to 3.

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 arranged on the outside of the guide catheter, a pusher mouthpiece (connection portion) that is arranged at the rear end of the pusher tube and that positions the rear end of the pusher tube by connecting it to the operation portion 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 direction, and a mouthpiece that is arranged 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 circumferential surface of the guide catheter.

Patent document 2 describes a tube stent delivery device having an inner catheter on whose outer periphery a tube stent is attached so as to be freely axially movable at its distal end, and an outer catheter attached so as to be freely axially movable on the outer periphery of the inner catheter located on the proximal end side of the tube stent. In patent document 2, the inner catheter is capable of being inserted through the through hole of the tube stent.

Patent document 3 describes a stent kit that is composed of 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 that is formed with an inner arc portion of the same shape as the stent arc portion and is inserted into the inside of the tube stent so that the positions of the inner arc portion and the stent arc portion are aligned.

JP 2006-204476 A Patent No. 6322374 Patent No. 5408682

The endoscopic treatment tool described in Patent Document 1 has a guide catheter disposed in the inner cavity of a drainage tube, and the distal end of the guide catheter is configured to be movable distal to the distal end of the drainage tube. The tube stent transport device described in Patent Document 2 has an inner catheter disposed in the inner cavity of a tube stent, and the distal end of the inner catheter is configured to be movable distal to 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 distal to the distal end of the stent 12. A similar embodiment is shown in Figure 5 of Patent Document 3. Thus, in Patent Documents 1 to 3, the distal end of an inner tube member such as a guide catheter or inner catheter disposed in the inner cavity of a tube stent is configured to be movable distal to the distal end of the tube stent.

Incidentally, a tube stent is inserted by inserting an inner tube member along a guide wire that has already been inserted into a biological lumen, and then inserting the tube stent along the inserted inner tube member. In this case, a step occurs between the guide wire and the inner tube member, and a step also occurs between the inner tube member and the tube stent, resulting in the presence of two steps. In particular, it has been reported that the latter step causes resistance to insertion in clinical practice, making it difficult to insert the tube stent into the narrowed or blocked area.

The present invention was made in consideration of the above-mentioned circumstances, and its purpose is to provide a medical device that includes an in-vivo indwelling tube that can be easily inserted into a stenosed or blocked area.

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 disposed in an inner cavity of the in-vivo tube and having a longitudinal direction and a proximal end and a distal end, wherein the in-vivo 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 distal to the position of the inner diameter Sd1, and the inner tubular member is movable in the longitudinal direction within the inner cavity of the in-vivo tube but a distal end of the inner tubular member cannot 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 tube member is disposed in a section from the distal end of the indwelling tube to a position that is 50% of the longitudinal length of the indwelling tube.
[3] The medical device according to [1] or [2], wherein a space is provided between the distal end of the inner cylindrical member and an inner wall of the indwelling tube in the longitudinal direction of the indwelling tube.
[4] The medical device according to any one of [1] to [3], wherein an inner diameter of the indwelling tube in the space is larger than an outer diameter of the distal end of the inner cylindrical member.
[5] The medical device according to any one of [1] to [4], wherein the movement of the inner tube member in a distal direction in the longitudinal direction is restricted in the lumen of the in-vivo indwelling tube.
[6] The medical device according to any one of [1] to [5], further comprising an outer tube member having a longitudinal direction, the outer tube member being disposed outside the inner tube member proximal to the proximal end of the in-vivo indwelling tube, and the outer tube member and the inner tube member being fixed to each other 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 tubular member in a section from the distal end of the inner tubular member to a position 40 cm proximally from the distal end.
[8] The medical device according to any one of [1] to [7], wherein the in-vivo indwelling tube has a thick-walled portion in the longitudinal direction, and the thick-walled portion is disposed distal to the distal end of the inner cylindrical member.
[9] The medical device according to any one of [1] to [8], wherein the in-vivo 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 in-vivo indwelling tube has an arcuate portion that is curved in an arc shape, and a non-arcuate portion proximal to the arcuate portion.
[11] The medical device according to [10], wherein the arc portion of the indwelling tube is configured as a closed ring in a plan view.
[12] The medical device according to any one of [1] to [11], wherein the distal end of the inner cylindrical member cannot be moved distally beyond the distal end of the indwelling tube.
[13] The medical device according to any of [1] to [12], further comprising an outer tube member having a longitudinal direction, and a thread, the outer tube member being disposed outside the inner tube member proximal to a proximal end of the indwelling tube and movable in the longitudinal direction of the inner tube member, the outer tube member having a through hole in a side wall of a distal portion of the outer tube member, the indwelling tube having a through hole in a side wall of a proximal portion of the indwelling tube, the thread being configured as a ring that passes through the through hole of the outer tube member and is closed, a part of the distal end of the outer tube member distal to the through hole of the outer tube member is disposed within the ring, and the ring of the thread is passed through the through hole of the indwelling tube, and the inner tube member is disposed within the ring.

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 so as not to move distally beyond the distal end of the in vivo indwelling tube. By preventing the distal end of the inner tubular member from moving 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 been a cause of insertion resistance. As a result, it becomes easier to insert the in vivo indwelling tube through a stenosed or blocked area.

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

The medical device according to 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 disposed in the lumen of the in-vivo tube having a longitudinal direction and a proximal end and a distal end, the in-vivo tube 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 is distal to the position of the inner diameter Sd1, and the inner tubular member is movable in the longitudinal direction in the lumen of the in-vivo tube, but the distal end of the inner tubular member cannot move distal to the distal end of the in-vivo tube.

The present invention will be described in more detail below based on the embodiments, but the present invention is not limited to the embodiments below, and can of course be modified within the scope of the above and below-mentioned intent, all of which are included in the technical scope of the present invention. In addition, hatching and component symbols may be omitted in each drawing for convenience, but in such cases, reference should be made to the specification or other drawings. Furthermore, the dimensions of various components in the drawings may differ from the actual dimensions, as priority is given to contributing to an understanding of the features of the present invention.

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 in-vivo indwelling tube 10 and an inner tube member 20. The in-vivo indwelling tube 10 has a longitudinal direction and a proximal end 10a and a distal end 10b. The inner tube member 20 has a longitudinal direction and a proximal end 20a and a distal end 20b. The proximal end 10a of the in-vivo indwelling tube 10 and the proximal end 20a of the inner tube member 20 refer to one end on the user side (the surgeon side), and the distal end 10b of the in-vivo indwelling tube 10 and the distal end 20b of the inner tube member 20 refer to one end on the opposite side to the proximal end (i.e., one end on the treatment subject side). The direction from the proximal end 10a to the distal end 10b of the in-vivo indwelling tube 10 and the direction from the proximal end 20a to the distal end 20b of the inner tube member 20 are each referred to as the longitudinal direction. A portion of the inner tube 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 tube member 20.

As shown in FIG. 1, the in-vivo indwelling tube 10 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 of the in-vivo indwelling tube 10 is distal to the position of the inner diameter Sd1. The inner tube member 20 can move longitudinally in the lumen of the in-vivo indwelling tube 10, but the distal end of the inner tube member 20 cannot move distal to the distal end 10b of the in-vivo indwelling tube 10. As a result, the distal end of the inner tube member 20 does not move distal to the distal end 10b of the in-vivo indwelling tube 10, eliminating the step between the inner tube member 20 and the in-vivo indwelling tube 10, which has traditionally caused insertion resistance, and making it easier to insert the in-vivo indwelling tube 10 into a stenosed or blocked area.

The distal end of the inner tube member 20 refers to the region from the distal end 20b of the inner tube member 20 to a position 60 mm longitudinally proximally away from the distal end 20b of the inner tube member 20. The distal end of the inner tube member 20 may have an outer diameter expansion region or an inner diameter expansion region formed therein, as described below. In addition, the distal end of the inner tube member 20 may have an X-ray opaque marker formed therein, as described below.

When the maximum outer diameter at the distal end of the inner tube member 20 is CD1, the maximum outer diameter CD1 may be smaller than the inner diameter Sd2 of the in-vivo indwelling tube 10, but is preferably smaller than the inner diameter Sd1 of the in-vivo indwelling tube 10 and larger than the inner diameter Sd2 of the in-vivo indwelling tube 10. In other words, it is preferable that the relationship Sd2<CD1<Sd1 is established between the maximum outer diameter CD1 at the distal end of the inner tube member 20, the inner diameter Sd1 of the in-vivo indwelling tube 10, and the inner diameter Sd2 of the in-vivo indwelling tube 10. This restricts the movement of the distal end of the inner tube member 20 in the longitudinal direction in the lumen of the in-vivo indwelling tube 10. As a result, it is possible to eliminate the step between the inner tube member 20 and the in-vivo indwelling tube 10, which has traditionally caused insertion resistance, making it easier to insert the in-vivo indwelling tube 10 into a narrowed or blocked area.

The movement of the inner tube member 20 in the longitudinal direction toward the distal end may be restricted within the lumen of the in-vivo retention tube 10. The movement of the inner tube member 20 may be restricted by the distal end 20b of the inner tube member 20 contacting the inner wall of the in-vivo retention tube 10 due to the relationship Sd2<CD1<Sd1 being established between the maximum outer diameter CD1 at the distal end of the inner tube member 20, the inner diameter Sd1 of the in-vivo retention tube 10, and the inner diameter Sd2 of the in-vivo retention tube 10, as described above, or by the inner tube member 20 being fixed on the proximal side. Alternatively, the inner tube member 20 may have a small outer diameter region 25 having a smaller diameter than the inner diameter of the in-vivo retention tube 10, and a large outer diameter region 26 having a larger diameter, and the large outer diameter region 26 may be restricted by contacting the in-vivo retention tube 10.

When the inner tube member 20 is fixed on the proximal side, for example, the proximal end of the inner tube member 20 may be fixed to a handle or the like. The method for fixing the proximal end of the inner tube 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 tube member 20 may be fixed to the handle body via this. When fixing the proximal end of the inner tube member 20 to a handle or the like, if the medical device 1 includes an outer tube member 50 having a longitudinal direction as described below, the outer tube member 50 and the inner tube member 20 may be fixed on the proximal side.

When the movement of the inner tube member 20 is restricted by fixing the inner tube member 20 on the proximal side, it is preferable that there is a space in the longitudinal direction of the in-vivo indwelling tube 10 between the distal end 20b of the inner tube member 20 and the inner wall of the in-vivo indwelling tube 10 when the inner tube member 20 is fixed. In particular, the presence of a space in the longitudinal direction between the distal end 20b of the inner tube member 20 and the distal side prevents the inner tube member 20 from being pressed in the longitudinal direction into the in-vivo indwelling tube 10 when the in-vivo indwelling tube 10 is inserted into the living body, making it easier to remove the inner tube member 20. Note that even when the movement of the inner tube member 20 is restricted by the contact of the large outer diameter region 26 of the inner tube member 20 with the in-vivo indwelling tube 10, it is preferable that there is a space in the longitudinal direction of the in-vivo indwelling tube 10, and the same effect can be expected. Furthermore, if the in-vivo indwelling tube 10 and the inner tube member 20 do not come into contact with each other, the distal end of the inner tube member 20 does not need to be rigid, so the wall thickness may be thin.

The relationship between the distal end 20b of the inner tube member 20 and the inner diameter of the in-vivo indwelling tube 10 is not particularly limited, but in the space between the distal end 20b of the inner tube member 20 and the space distal to it in the longitudinal direction, it is preferable that the outer diameter of the distal end 20b of the inner tube member 20 is smaller than the inner diameter Sd1 of the in-vivo indwelling tube 10. This makes it possible to more effectively prevent the inner tube member 20 from becoming embedded in the in-vivo indwelling tube 10.

The distal end 20b of the inner tube member 20 cannot move distally beyond the distal end 10b of the in-vivo indwelling tube 10. That is, the distal end 20b of the inner tube member 20 is present in the lumen of the in-vivo indwelling tube 10. By having the distal end 20b of the inner tube member 20 present in the lumen of the in-vivo indwelling tube 10, the step between the guide wire 9 and the inner tube member 20 can be eliminated, and the step between the guide wire 9 and the in-vivo indwelling tube 10 can be reduced, making it easier to insert the in-vivo indwelling tube 10 into a narrowed or blocked area of the lumen of the body. In addition, when the distal end of the inner tube member 20 is disposed in the lumen of the distal end of the in-vivo indwelling tube 10, the strength of the distal end of the in-vivo indwelling tube 10 is increased, making it easier to insert the in-vivo indwelling tube 10 into a narrowed or blocked area of the lumen of the body.

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

As shown in FIG. 1, there may be a space between the distal end 20b of the inner tube member 20 and the inner wall of the in-vivo indwelling tube 10 in the longitudinal direction of the in-vivo indwelling tube 10. That is, the distal end 20b of the inner tube member 20 and the inner wall of the in-vivo indwelling tube 10 may not abut. By having a space between the distal end 20b of the inner tube member 20 and the inner wall of the in-vivo indwelling tube 10 in the longitudinal direction of the in-vivo indwelling tube 10, the inner tube member 20 does not sink into the in-vivo indwelling tube 10, making it easier to remove the inner tube member 20. In addition, the rigidity at the distal end of the in-vivo indwelling tube 10 can be reduced.

The size of the space formed in the longitudinal direction of the in-vivo indwelling tube 10 is not particularly limited, but the shortest distance G between the distal end 20b of the inner tube member 20 and the inner wall of the in-vivo indwelling tube 10 in the longitudinal direction of the in-vivo 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 in-vivo indwelling tube 10 is too short, the inner tube member 20 will be easily embedded in the in-vivo indwelling tube 10. There is also no particular upper limit to the shortest distance G, but for example, 15 mm or less is preferable. If the shortest distance G of the space in the longitudinal direction of the in-vivo indwelling tube 10 is too long, the rigidity of the medical device 1 will be easily reduced in the space.

15, the medical device 1 may have a structure in which an outer tube member 50 is disposed at the base end side of a tube to be placed in a living body 10, an inner tube member 20 is disposed in the lumen of the tube to be placed in a living body 10 and the outer tube member 50, and the base end side of the tube to be placed in a living body 10 and the tip side of the outer tube member 50 are connected by a filament 60. In this case, a slight gap is formed between the tube to be placed in a living body 10 and the outer tube member 50 depending on the way the filament is stretched. This gap disappears when the outer tube member 50 pushes the tube to be placed in a living body 10 when the tube to be placed in a living body 10 is inserted, and when the proximal side of the inner tube member 20 and the outer tube member 50 are fixed, the inner tube member 20 advances within the tube to be placed in a living body 10 by the gap distance W. Therefore, in order to prevent the inner tube member 20 from being embedded in the tube to be placed in a living body 10, it is preferable that the spatial distance G in the longitudinal direction of the tube to be placed in a living body 10 is 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 at least 1 mm longer than the gap distance W, and more preferably at least 2 mm longer. From the viewpoint of the rigidity of the medical device 1, it is preferable that the spatial distance G in the longitudinal direction of the in-vivo indwelling tube 10 is 15 mm or less longer than the gap distance W.

The advancement of the inner tube member 20 is also related to the radial spatial distance H between the inner diameter of the in-vivo retention tube 10 and the outer diameter of the inner tube member 20. If the distance H is small, sliding friction occurs between the inner surface of the in-vivo retention tube 10 and the outer surface of the inner tube member 20 when the in-vivo retention tube 10 is captured at the narrowed area, and the advancement of the inner tube member 20 is inhibited. On the other hand, if the distance H is large, the inner tube member 20 is likely to advance even if the in-vivo retention tube 10 is captured at the narrowed area. However, if the sliding friction between the inner surface of the in-vivo retention tube 10 and the outer surface of the inner tube member 20 is large, the load when removing the inner tube member 20 tends to be high, and if the sliding friction is small, the load when removing the inner tube member 20 tends to be low. Therefore, the outer diameter of the inner tube 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.

As shown in FIG. 1, the distal end 20b of the inner tube member 20 is preferably disposed in a section R from the distal end 10b of the in-vivo retention tube 10 to position r, where r is the position where the length is 50% of the longitudinal length L of the in-vivo retention tube 10. By disposing the inner tube member 20 in the lumen of the in-vivo retention tube 10, the rigidity of the medical device 1 is increased, making it easier to insert the in-vivo retention tube 10 into a narrowed or blocked area of the body lumen. Therefore, by disposing the distal end 20b of the inner tube member 20 in section R of the in-vivo retention tube 10, it is possible to ensure the rigidity of the medical device 1 while preventing the inner tube member 20 from sinking into the in-vivo retention tube 10.

The minimum inner diameter of the inner diameter of the in-vivo retention tube 10 may be smaller than the maximum outer diameter of the inner tube member 20 in the section from the distal end 20b of the inner tube member 20 to a position 40 cm proximally away from the distal end 20b. By making the minimum inner diameter of the in-vivo retention tube 10 smaller than the maximum outer diameter of the inner tube member 20, it is possible to prevent the distal end of the inner tube member 20 from moving distally beyond the distal end 10b of the in-vivo retention tube 10.

1, the in-vivo indwelling tube 10 may have a tapered region 15 at the distal end of the in-vivo indwelling tube 10, where the outer diameter SD3 of the in-vivo indwelling tube 10 decreases toward the distal end 10b. The tapered region 15 at the distal end of the in-vivo indwelling tube 10 makes it easier to insert the distal end of the in-vivo indwelling tube 10 into a narrowed or blocked area of a body lumen. The position at which the tapered region 15 is located may be, for example, a section from the distal end 10b of the in-vivo indwelling tube 10 to a position 30 mm away from the distal end 10b of the in-vivo indwelling tube 10 in the longitudinal direction proximal to the distal end 10b of the in-vivo indwelling tube 10, a section from the distal end 10b of the in-vivo indwelling tube 10 to a position 20 mm away from the distal end 10b of the in-vivo indwelling tube 10 in the longitudinal direction proximal to the distal end, or a section from the distal end 10b of the in-vivo indwelling tube 10 to a position 10 mm away from the distal end 10b of the in-vivo indwelling tube 10 in the longitudinal direction proximal to the distal end.

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

The thick portion is located in the longitudinal space between the distal end 20b of the inner tube member 20 and the inner wall of the in vivo retention tube 10, and the thick portion is preferably 110% or more thick, more preferably 120% or more thick, and even more preferably 130% or more thick, of the thickness of the in vivo retention tube 10 at the position of the inner diameter Sd1 of the in vivo retention tube 10. By having a thick portion in the longitudinal space between the distal end 20b of the inner tube member 20 and the inner wall of the in vivo retention tube 10, the strength of the in vivo retention tube 10 can be increased in the portion where the inner tube member 20 is not positioned. The thick portion of the in vivo retention tube 10 may be tapered, and may have a step inside or outside the in vivo retention tube 10. In addition, methods for increasing the strength of the in-vivo indwelling tube 10 in the longitudinal space between the distal end 20b of the inner tubular 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.

Figure 2 is a cross-sectional view showing another embodiment of the medical device according to the present invention. The same symbols are used for the same parts as in Figure 1 to avoid duplicate explanations. The same applies below. The in-vivo retention tube 10 of the medical device 1 shown in Figure 2 has a through hole 16 in the side wall of the in-vivo retention tube 10. The in-vivo retention tube 10 also has a locking flap 13a on the outer surface of the proximal end of the in-vivo retention tube 10, and a locking flap 13b on the outer surface of the distal end. The inner tube 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 tube member 20. The inner tube member 20 has a small outer diameter region 25 having an outer diameter smaller than the inner diameter at the proximal end 10a of the indwelling tube 10, and a large outer diameter region 26 having an outer diameter larger than the inner diameter at the proximal end 10a of the indwelling tube 10, proximal to the small outer diameter region 25, and the small outer diameter region 25 and the large outer diameter region 26 are arranged side by side in the longitudinal direction of the inner tube member 20. The distal end 20c of the large outer diameter region 26 of the inner tube member 20 abuts against the proximal end 10a of the indwelling tube 10, thereby restricting the movement of the inner tube member 20 in the longitudinal direction.

2, the in-vivo indwelling tube 10 may have a through hole 16 in the side wall of the in-vivo indwelling tube 10. This allows fluid flowing in the body lumen to pass from the outside of the in-vivo indwelling tube 10 through the through hole 16 into the inside of the in-vivo indwelling tube 10 and flow from the distal side to the proximal side of the in-vivo indwelling tube 10, making drainage possible even when the in-vivo indwelling tube 10 is placed in the body lumen. The position of the through hole 16 on the side wall of the in-vivo indwelling tube 10 is not particularly limited, and it may be located near the center in the longitudinal direction of the in-vivo indwelling tube 10 as shown in FIG. 2, or it may be located in the proximal and/or distal part of the in-vivo indwelling tube 10.

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, even more preferably 1.3 mm or less. In other words, 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, even more preferably 0.5 mm to 1.3 mm.

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

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. In other words, 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.

When the in vivo retention tube 10 has multiple through holes 16 in the 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 retention tube 10 has multiple through holes 16 in the side wall, the arrangement of each through hole is not particularly limited and each through hole may be formed in a row in the longitudinal direction of the in vivo retention tube 10, may be formed in a row in the circumferential direction of the in vivo retention tube 10, or may be formed in a spiral shape with respect to the longitudinal direction of the in vivo retention tube 10.

As shown in FIG. 2, the in-vivo indwelling tube 10 may have locking flaps 13a and 13b. By having the locking flap 13a on the outer surface of the proximal end of the in-vivo indwelling tube 10, for example, the in-vivo indwelling tube 10 placed in the bile duct or pancreatic duct can be prevented from entering the bile duct or pancreatic duct through the duodenal papilla. By having the locking flap 13b on the outer surface of the distal end of the in-vivo indwelling tube 10, for example, the in-vivo indwelling tube 10 placed in the bile duct or pancreatic duct can be prevented from falling off into the duodenum.

The in vivo placement tube 10 may have a locking flap 13a only on the outer surface of the proximal end of the in vivo placement tube 10, or may have a locking flap 13b only on the outer surface of the distal end of the in vivo placement tube 10, but it is preferable for the in vivo placement tube 10 to have locking flaps on both the outer surface of the proximal end and the outer surface of the distal end as shown in Figure 2.

The number of locking flaps 13a arranged at the proximal end of the in-vivo indwelling tube 10 and the number of locking flaps 13b arranged at the distal end of the in-vivo indwelling tube 10 are not particularly limited, and each may be one, or, for example, two or more, or three or more, with five or less being preferable. 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.

When multiple locking flaps 13a are arranged at the proximal end of the in-vivo retention tube 10 or multiple locking flaps 13b are arranged at the distal end of the in-vivo retention tube 10, the arrangement of each locking flap is not particularly limited, but it is preferable that each locking flap is arranged at equal intervals in the circumferential direction of the in-vivo retention tube 10. This can enhance the effect of preventing the in-vivo retention tube 10 from shifting out of position.

When multiple locking flaps 13a are arranged at the proximal end of the in-vivo retention tube 10, or multiple locking flaps 13b are arranged at the distal end of the in-vivo retention tube 10, the length from the base to the free end of the locking flap and the width and thickness of the locking flap are not particularly limited and may all be the same or different. For example, if the length, width, and thickness of each locking flap are the same, manufacturing is easy. Also, by making the length, width, and thickness of each locking flap different, the strength of each locking flap can be changed. As a specific example, the strength of locking flaps arranged in areas that are prone to stress and may break can be increased, and the strength of locking flaps arranged in areas where flexibility is required can be decreased.

The method of 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 a cut in the surface of the end of the tube body constituting the in vivo placement tube 10 and protruding a part of the tube body 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 placement tube 10.

　The resin material constituting the in vivo placement tube 10 (i.e., the resin material constituting the tube body that is the raw material of the in vivo placement tube 10) can be a known resin, and examples thereof 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 may be used alone or in combination of two or more. Among them, polyamide-based resins, polyurethane-based resins, polyolefin-based resins, and fluorine-based resins are preferably used. By containing at least one of polyamide-based resins, polyurethane-based resins, polyolefin-based resins, and fluorine-based resins, the in vivo placement tube 10 can achieve both biocompatibility and flexibility.

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 preferable. A single-layer structure makes it easy to manufacture. If it is a multi-layer structure, the type of resin material constituting each layer is not particularly limited, and may be the same or different.

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 aligned in the longitudinal direction and joined together.

When the locking flap member is joined to the outer surface of the tube body to form the locking flap, the material constituting the locking flap member is not particularly limited and may be the same as the material constituting the tube body or may be different, but it is preferable that the material is the same. By making the material the same, the bonding strength of the locking flap member to the tube body can be increased.

Methods for joining the tube body and the locking flap member include, for example, heat welding, ultrasonic welding, and adhesion with adhesives, and joining by heat welding is 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.

The locking flap is preferably formed by cutting a notch into the surface of the end of the tube body. This makes the locking flap less likely to fall off than if the locking flap was formed by joining the locking flap member to the outer surface of the tube body.

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

As shown in FIG. 2, the inner tube member 20 may have an X-ray opaque marker 17 at the distal end of the inner tube member 20. By having the X-ray opaque marker 17, the position of the inner tube member 20 can be confirmed under X-ray fluoroscopy. When the X-ray opaque marker 17 is arranged at the distal end of the inner tube member 20, the number of X-ray opaque markers 17 is not particularly limited, and may be one, two or more, or three or more. In FIG. 2, one X-ray opaque marker 17 is provided at the distal end of the inner tube member 20. The shape of the X-ray opaque marker 17 is not particularly limited, and examples include a tubular shape (e.g., a cylindrical shape, a polygonal tubular shape, etc.), a shape with a C-shaped cross section with a slit in the tube, and a coil shape with a wire wound around it. Among these, a tubular shape is preferable. The radiopaque marker 17 can be made of any known material, such as radiopaque materials such as lead, barium, iodine, tungsten, gold, platinum, iridium, stainless steel, titanium, and cobalt-chromium alloys.

2, the inner tube member 20 may have a small outer diameter region 25 having an outer diameter smaller than the inner diameter at the proximal end 10a of the in-vivo retention 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 at the proximal end 10a of the in-vivo retention 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 tube member 20. In this way, when the inner tube member 20 is inserted into the lumen of the in-vivo retention tube 10, the small outer diameter region 25 of the inner tube member 20 is arranged in the lumen of the in-vivo retention tube 10. On the other hand, the distal end 20c of the large outer diameter region 26 of the inner tube member 20 abuts against the proximal end 10a of the in-vivo retention tube 10, so that the large outer diameter region 26 of the inner tube member 20 is not arranged in the lumen of the in-vivo retention tube 10. In this case, the inner tube member 20 plays the role of the outer tube member 50 described below, and can also serve as a pusher member for the in-vivo indwelling tube 10. In addition, by adjusting the length of the small outer diameter region 25 of the inner tube member 20 and the length of the in-vivo 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 tube member 20 and the inner wall of the in-vivo indwelling tube 10 in the longitudinal direction of the in-vivo indwelling tube 10.

Figure 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 Figure 3 has a tapered region 18 at the distal end of the in vivo indwelling tube 10, where the inner diameter decreases toward the distal end.

As shown in FIG. 3, when the inner diameter of the in-vivo indwelling tube 10 is Sd4, the distal end of the in-vivo indwelling tube 10 may have a tapered region 18 in which the inner diameter Sd4 decreases toward the distal end 10b. By providing the tapered region 18 at the distal end of the in-vivo indwelling tube 10, a strength gradient can be created at the distal end of the in-vivo indwelling tube 10.

The position where the reduced diameter region 18 of the in-vivo retention tube 10 is formed is preferably the distal end of the in-vivo retention tube 10, and for example, is preferably a section from the distal end 10b of the in-vivo retention tube 10 to a position 30 mm longitudinally proximally from the distal end 10b of the in-vivo retention tube 10, a section from the distal end 10b of the in-vivo retention tube 10 to a position 20 mm longitudinally proximally, or a section from the distal end 10b of the in-vivo retention tube 10 to a position 10 mm longitudinally proximally from the distal end 10b of the in-vivo retention 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 away from the distal end 10b of the in-vivo tube 10 on the proximal side, or may be proximal to a position 5 mm longitudinally away from the distal end 10b of the in-vivo tube 10 on the proximal side, or may be proximal to a position 8 mm longitudinally away from the distal end 10b of the in-vivo tube 10 on the proximal side.

Figure 4 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 Figure 4 has a tapered region 18 at the distal end of the in-vivo indwelling tube 10, where the inner diameter decreases toward the distal end 10b of the in-vivo indwelling tube 10, and the tapered region 18 extends to the distal end 10b of the in-vivo indwelling tube 10.

As shown in FIG. 4, the inner diameter Sd4 of the in-vivo indwelling tube 10 may be smallest at the distal end 10b of the in-vivo indwelling tube 10. In other words, the distal end of the reduced diameter region 18 in the longitudinal direction of the in-vivo indwelling tube 10 may coincide with the distal end 10b of the in-vivo indwelling tube 10. This reduces the rigidity of the distal end of the in-vivo indwelling tube 10, making it less likely to damage the walls of the lumen in the body.

Figure 5 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 Figure 5 has a through hole 16 in the distal part of the in-vivo indwelling tube 10 that connects 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.

As shown in FIG. 5, the in-vivo indwelling tube 10 may have a through hole 16 in the distal portion of the in-vivo indwelling tube 10. This allows the fluid flowing in the body lumen to pass through the through hole 16, enter from the outside of the in-vivo indwelling tube 10 to the inside, and flow from the distal side to the proximal side of the in-vivo indwelling tube 10, making drainage possible even when the in-vivo indwelling tube 10 is placed in the body lumen.

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

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 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, even more preferably 1.0 mm or less. In other words, 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, even more preferably 0.5 to 1.0 mm.

The opening shape of the through hole 16 disposed in the distal portion of the in vivo indwelling tube 10 is not particularly limited, and may be, for example, a circle, an ellipse, or a rectangle (e.g., a triangle, a square, etc.). From the viewpoint of ease of processing, the opening shape of the through hole 16 disposed in the distal portion of the in vivo indwelling tube 10 is preferably a circle or an ellipse.

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, one or two 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, for example, six or less is preferable, five or less is more preferable, and four or less is even more preferable. In other words, the number of through holes 16 arranged in the distal portion of the in vivo indwelling tube 10 may be one to six, two to five, or two to four.

When the in vivo retention tube 10 has multiple 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 retention tube 10 has multiple through holes 16 in the distal portion, the arrangement of each through hole is not particularly limited and may be formed in a line in the longitudinal direction of the in vivo retention tube 10, may be formed in a line in the circumferential direction of the in vivo retention tube 10, or may be formed in a line in a spiral shape relative to the longitudinal direction of the in vivo retention tube 10.

As shown in FIG. 5, the in-vivo indwelling tube 10 may have an X-ray opaque marker 17. By having the X-ray opaque marker 17, the position of the in-vivo indwelling tube 10 can be confirmed under X-ray fluoroscopy.

The location of the X-ray opaque marker 17 is not particularly limited, but is preferably the distal portion of the in vivo placement tube 10, more preferably distal to the region where the locking flap is present in the distal portion of the in vivo placement tube 10 and/or proximal to the region where the locking flap is present in the distal portion of the in vivo placement tube 10, and even more preferably both distal to the region where the locking flap is present in the distal portion of the in vivo placement tube 10 and proximal to the region where the locking flap is present in the distal portion of the in vivo placement tube 10. The region where the locking flap is present 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.

The X-ray impermeable marker 17 may be further disposed in the proximal portion of the in-vivo indwelling tube 10, more preferably on the distal side of the region where the locking flap is present in the proximal portion of the in-vivo indwelling tube 10 and/or on the proximal side of the region where the locking flap is present in the proximal portion of the in-vivo indwelling tube 10, and even more preferably on both the distal side of the region where the locking flap is present in the proximal portion of the in-vivo indwelling tube 10 and the proximal side of the region where the locking flap is present in the proximal portion of the in-vivo indwelling tube 10. The proximal portion of the in-vivo indwelling tube 10 refers to, for example, the region from the proximal end 10a of the in-vivo indwelling tube 10 to a position that is 50% of the longitudinal length L of the in-vivo indwelling tube 10. The distal portion of the in-vivo indwelling tube 10 refers to, for example, the region from the distal end 10b of the in-vivo indwelling tube 10 to a position that is 50% of the longitudinal length L of the in-vivo indwelling tube 10.

The number of X-ray opaque markers 17 is not particularly limited, and may be one, two or more, or three or more. In FIG. 5, one is provided on the distal side of the region where the locking flap is present in the distal portion of the in-vivo indwelling tube 10, and one is provided on the proximal side, and one is provided on the distal side of the region where the locking flap is present in the proximal portion of the in-vivo indwelling tube 10, and one is provided on the proximal side.

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

FIG. 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 in-vivo indwelling tube 10 and the inner tubular member 20. As shown in FIG. 6, when the outer diameter of the inner tubular member 20 is CD2, the inner tubular member 20 may have an outer diameter expansion region 22 at the distal end of the inner tubular member 20 where the outer diameter CD2 increases toward the distal end 20b. This makes it easier for the distal end of the inner tubular member 20 to abut against the lumen wall of the in-vivo indwelling tube 10, reducing the misalignment between the axis of the in-vivo indwelling tube 10 and the axis of the inner tubular member 20. As a result, the guide wire 9 inserted from the distal end 10b of the in-vivo indwelling tube 10 can be easily inserted from the distal end 20b of the inner tubular member 20.

The position where 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 away from the distal end 20b of the inner tube member 20 in the longitudinal direction proximal to the distal end 20b of the inner tube member 20, a section from the distal end 20b of the inner tube member 20 to a position 50 mm away from the distal end 20b of the inner tube member 20 in the longitudinal direction proximal to the distal end, or a section from the distal end 20b of the inner tube member 20 to a position 40 mm away from the distal end 20b of the inner tube member 20 in the longitudinal direction proximal to the distal end.

FIG. 7 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 in-vivo indwelling tube 10 and the inner tubular member 20. As shown in FIG. 7, when the inner diameter at the distal end of the inner tubular member 20 is Cd1, the inner tubular member 20 may have an inner diameter expansion region 23 at the distal end of the inner tubular member 20 where the inner diameter Cd1 increases toward the distal end 20b. This makes the opening at the distal end 20b of the inner tubular member 20 larger, 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 tubular member 20.

When the inner tube member 20 has an inner diameter expansion region 23, as shown in FIG. 7, it is preferable that the outer diameter of the inner tube member 20 in the inner diameter expansion region 23 of the inner tube member 20 increases toward the distal end 20b of the inner tube member 20. That is, as shown in FIG. 7, the outer diameter of the inner tube member 20 in the inner diameter expansion region 23 may form an outer diameter expansion region.

The position where the inner diameter expansion region 23 is formed is not particularly limited, but it is preferable that, for example, it is a section from the distal end 20b of the inner tube member 20 to a position 60 mm away from the distal end 20b of the inner tube member 20 in the longitudinal direction proximal to the distal end 20b of the inner tube member 20, a section from the distal end 20b of the inner tube member 20 to a position 50 mm away from the distal end 20b of the inner tube member 20 in the longitudinal direction proximal to the distal end, or a section from the distal end 20b of the inner tube member 20 to a position 40 mm away from the distal end 20b of the inner tube member 20 in the longitudinal direction proximal to the distal end.

From the viewpoint of insertability of the guidewire, the inner diameter at the distal end position of the inner tube member 20 is preferably larger than the inner diameter Sd2 of the in-vivo indwelling tube 10 located distal to the inner tube 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 tube member 20 at the distal end of the inner tube member 20 has not expanded.

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 distal end of the in-vivo indwelling tube 10 and the inner tubular member 20. As shown in Figure 8, the inner tubular member 20 may have a taper 24 at the distal end of the inner tubular 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 tubular member 20 will get caught even if it comes into contact with the inner wall of the in-vivo indwelling tube 10, reducing the pull-out load of the inner tubular member 20 and improving operability for the operator.

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

<Judgment method>
10, a point to be determined on the central axis 11 of the indwelling tube 10 in a plan view is designated as point a, a point 2.5 mm away from point a in the proximal direction of the indwelling tube 10 along the central axis 11 is designated as point b, and a point 5 mm away from point a in the proximal direction of the indwelling tube 10 along the central axis 11 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. A point on the virtual circle 12 that is closer to the proximal end 10a of the indwelling tube 10 than point a is defined as point x, and when the central angle with respect to the arc ax is 45°, if the indwelling tube 10 intersects with the line segment ox, it is determined that point a belongs to the arc portion A of the indwelling tube 10, and if the indwelling tube 10 does not intersect with the line segment ox, it is determined that point a belongs to the non-arc portion B of the indwelling tube 10. When the indwelling tube 10 intersects with the line segment ox, it means that a part of the indwelling tube 10 intersects with the line segment ox as shown in Fig. 10, or the entire indwelling tube 10 intersects with the line segment ox as shown in Fig. 11. When the indwelling tube 10 does not intersect with the line segment ox, it means that the indwelling tube 10 does not intersect with the line segment ox and is separated from the line segment ox as shown in Fig. 12.

The position where the inner tube member 20 is disposed inside the in vivo indwelling tube 10 is not particularly limited, but it is preferable that the inner tube member 20 is disposed in at least a part of the non-arc portion B of the in vivo indwelling tube 10 and not disposed in the arc portion A of the in vivo indwelling tube 10. This reduces the pull-out load of the inner tube member 20 when the in vivo indwelling tube 10 is placed in the affected area, improving the operator's workability and making it easier to position the in vivo indwelling tube 10. If the in vivo indwelling tube 10 is, for example, straight, friction between the in vivo indwelling tube 10 and the inner tube member 20 is small, so the pull-out load of the inner tube member 20 when the in vivo indwelling tube 10 is placed in the affected area can be reduced.

Fig. 13 is a cross-sectional view showing another embodiment of the medical device according to the present invention. The medical device 1 shown in Fig. 13 has an in-vivo indwelling tube 10 and an inner tubular member 20, and the in-vivo indwelling tube 10 has a locking flap 13a on the outer surface of the proximal end of the in-vivo indwelling tube 10. The in-vivo indwelling tube 10 also has an arc portion A that is curved in an arc shape, and a non-arc portion B proximal to the arc portion A. The arc portion A is configured in a closed ring shape in a plan view. This makes it possible to prevent the in-vivo indwelling tube 10 placed in, for example, the bile duct or pancreatic duct from falling off the bile duct or pancreatic duct into the duodenum.

By providing an engagement flap 13a on the outer surface of the proximal end of the in-vivo indwelling tube 10, for example, the in-vivo indwelling tube 10 placed in the bile duct or pancreatic duct can be prevented from entering the bile duct or pancreatic duct through the duodenal papilla.

If the in vivo placement tube 10 has an 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 placement tube 10.

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 has an in-vivo indwelling tube 10 and an inner tube member 20, and the in-vivo indwelling tube 10 has an arc portion A that is curved in an arc shape, a non-arc portion B proximal to the arc portion A, and a proximal arc portion D proximal to the arc portion A. The arc portion A and the proximal arc portion D are configured in a closed ring shape when viewed in a plane.

The inner tube member 20 is disposed in the cavity of the proximal arc portion D, thereby improving pushability. When the in-vivo indwelling tube 10 is to be disposed in the living body, the proximal arc portion D of the in-vivo indwelling tube 10 may be disposed on the duodenal side from the duodenal papilla. This makes it difficult for the in-vivo indwelling tube 10 to become heavy even if the inner tube member 20 is disposed in the cavity of the proximal arc portion D. The in-vivo indwelling tube 10 is configured as a closed ring in a plan view, thereby preventing the in-vivo indwelling tube 10 disposed in the bile duct or pancreatic duct from falling out of the bile duct or pancreatic duct to the duodenal side, for example. The proximal arc portion D of the in-vivo indwelling tube 10 is configured as a closed ring in a plan view, thereby preventing the in-vivo indwelling tube 10 disposed in the bile duct or pancreatic duct from entering the bile duct or pancreatic duct from the duodenal papilla.

The medical device 1 may further include an outer tube member 50 having a longitudinal direction, and the outer tube member 50 may be disposed outside the inner tube member 20 proximal to the proximal end 10a of the in-vivo indwelling tube 10. In this case, it is preferable that the outer tube member 50 is configured to be movable in the longitudinal direction of the inner tube member 20.

The outer tube member 50 and the inner tube member 20 may be fixed on the proximal side. This can restrict the inner tube member 20 from moving in the distal direction in the longitudinal direction within the lumen of the in-vivo indwelling tube 10. When the outer tube member 50 is fixed on the proximal side, for example, the proximal end of the outer tube member 50 may be fixed to a handle or the like. There are no particular limitations on the method for fixing the proximal end of the outer tube member 50 to a handle or the like. 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 outer tube member 50 may be fixed to the handle body via this.

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

As shown in FIG. 15, the outer tube member 50 may be disposed proximal to the proximal end 10a of the in-vivo indwelling tube 10 and outside the inner tube member 20. In this case, it is preferable that the outer tube member 50 is configured to be movable in the longitudinal direction of the inner tube member 20.

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 from the distal end of the outer tube member 50 in the longitudinal direction on the proximal side. The in vivo retention tube 10 may have a through hole 71 in the side wall of the proximal portion of the in vivo retention tube 10.

The thread body 60 is configured as a ring that passes through the through hole 72 of the outer tube member 50 and is closed, and a part 51 of the distal end of the outer tube member 50 distal to the through hole 72 of the outer tube member 50 is disposed in the ring, and the ring of the thread body 60 may be passed through the through hole 71 of the in vivo retention tube 10, and the inner tube member 20 may be disposed in the ring. In this case, a part 14 of the proximal end of the in vivo retention tube 10 is not disposed in the ring of the thread body 60. The inner tube member 20 is disposed in the ring formed by the thread body 60, thereby connecting the in vivo retention tube 10 and the outer tube member 50. This makes it easier for force applied from the hand side to be transmitted to the in vivo retention tube 10 through the outer tube member 50, making it easier to push the in vivo retention tube 10 distally and transport the in vivo retention tube 10 to the affected area. In addition, even after the in-vivo indwelling tube 10 is delivered to the affected area, the in-vivo indwelling tube 10 can be moved proximally by pulling the inner tubular member 20 and the outer tubular member 50 proximally, making it easier to position the in-vivo indwelling tube 10 when it is placed. In addition, the thread 60 is inserted into the through-hole 72 of the outer tubular member 50, and the ring of the thread 60 is inserted into the through-hole 71 of the in-vivo indwelling tube 10, making it easier to connect the in-vivo indwelling tube 10 and the outer tubular member 50 by the thread 60. In addition, the thread 60 is configured as a closed ring, and the inner tubular member 20 is arranged inside the ring, so that the connection between the in-vivo indwelling tube 10 and the outer tubular member 50 can be easily released by removing the inner tubular member 20 from the ring. This makes it easier to place the in-vivo indwelling tube 10 in the affected area.

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.

The thread body 60 may be, for example, a suture. By using a suture as the thread body 60, the thread body 60 can be made flexible while maintaining its durability, making it less likely for the thread body 60 to damage the in-vivo indwelling tube 10 or the luminal wall of the in-vivo lumen.

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 may be used alone or in combination of two or more types. Among these, polyamide-based resins, polyester-based resins, polyurethane-based resins, polyolefin-based resins, and fluorine-based resins are preferably used.

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

When the in-vivo indwelling tube 10 is placed in the bile duct, the side of the in-vivo indwelling tube 10 that is placed on the duodenum side is the proximal side, and the opposite side (the gallbladder side or the liver side) is the distal side, and the distal end 10b of the in-vivo indwelling tube 10 may be placed on the gallbladder side or on the liver side. When the distal end 10b of the in-vivo indwelling tube 10 is placed on the liver side, a part of the distal end of the in-vivo indwelling tube 10 may be placed in the hepatic duct.

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).

The resin material constituting the inner tube member 20 may be any known resin, such as 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 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 resins are preferably used.

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. If it is a multi-layer structure, the resin materials constituting each layer may be the same or different.

The inner tube member 20 may be composed of one tube from the proximal end 20a to the distal end 20b of the inner tube member 20, or may be composed of multiple tubes arranged and joined in the longitudinal direction. By being composed of multiple tubes, the bending rigidity of the inner tube member 20 can be changed in the longitudinal direction. For example, by making the hardness of the material of the tube constituting the distal part of the inner tube member 20 lower than the hardness of the material of the tube constituting the proximal part of the inner tube member 20, the inner tube member 20 can have a low bending rigidity in the distal part and a high bending rigidity in the proximal part. The low bending rigidity of the distal part of the inner tube member 20 can improve the followability to the guide wire 9. The high bending rigidity of the proximal part of the inner tube member 20 can improve the pushability. The distal part of the inner tube member 20 refers to, for example, the region from the distal end 20b of the inner tube member 20 to a position that is 50% of the longitudinal length of the inner tube member 20. The proximal portion of the inner tube member 20 refers to, for example, the region from the proximal end 20a of the inner tube member 20 to a position that is 50% of the longitudinal length of the inner tube member 20.

The resin material constituting the outer tube member 50 may be any known resin, such as 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 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 resins are preferably used.

The structure of the outer tube member 50 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. If it is a multi-layer structure, the resin materials constituting each layer may be the same or different.

The outer tube member 50 may be composed of one tube from the proximal end to the distal end of the outer tube member 50, or may be composed of multiple tubes arranged in the longitudinal direction and joined together. By being composed of multiple tubes, the bending rigidity can be changed in the longitudinal direction of the outer tube member 50. For example, by making the hardness of the material of the tube constituting the distal part of the outer tube member 50 lower than the hardness of the material of the tube constituting the proximal part of the outer tube member 50, the outer tube member 50 can have a low bending rigidity in the distal part and a high bending rigidity in the proximal part. The low bending rigidity of the distal part of the outer tube member 50 can improve the followability to the guide wire. The distal part of the outer tube member 50 refers to, for example, the region from the distal end of the outer tube member 50 to a position that is 50% of the longitudinal length of the outer tube member 50. The proximal part of the outer tube member 50 refers to, for example, the region from the proximal end of the outer tube member 50 to a position that is 50% of the longitudinal length of the outer tube member 50.

The resin material constituting the outer tube member 50 and the resin material constituting the inner tube member 20 may be the same or different.

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 is the same as the maximum outer diameter of the in-vivo indwelling tube 10.

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 the above-mentioned Japanese Patent Application No. 2024-002406 are incorporated by reference into this application.

LIST OF SYMBOLS 1 Medical device 9 Guide wire 10 Tube to be placed in a living body 10a Proximal end of tube to be placed in a living body 10b Distal end of tube to be placed in a living body 11 Central axis 12 Virtual circle 13a, 13b Locking flap 14 Part of proximal end of inner tubular member 15 Diameter-reduced region in which outer diameter SD3 decreases toward the distal end 16 Through hole 17 X-ray opaque marker 18 Diameter-reduced region of inner diameter of tube to be placed in a living body 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 enlarged region 23 Inner diameter enlarged 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 part of the distal end of the outer tubular member located distal to the through hole of the outer tubular member 60 thread 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 to be left in place in vivo Sd1 inner diameter of the tube to be left in place in vivo Sd2 inner diameter of the tube to be left in place in vivo a, b, c point on the central axis of the tube to be left in place in vivo o center of imaginary circle x point on imaginary circle r position where the length is 50% of the longitudinal length of the tube to be left in place in vivo A arc portion B non-arc portion D proximal arc portion G spatial distance in the longitudinal direction of the tube to be left in place in vivo H radial spatial distance between the inner diameter of the tube to be left in place in vivo and the outer diameter of the inner tubular member L longitudinal length of the tube to be left in place in vivo R Section W from the distal end of the indwelling tube to position r: Distance of the gap in the longitudinal direction of the indwelling tube

Claims (13)

an in-vivo indwelling tube having a longitudinal direction and a proximal end and a distal end;
a medical device including an inner tube member that is disposed in an inner cavity 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, and the position of the inner diameter Sd2 in the longitudinal direction is distal to the position of the inner diameter Sd1;
The medical device wherein the inner cylindrical member is movable in the longitudinal direction within the lumen of the indwelling tube, but the distal end of the inner cylindrical member cannot move distally beyond the distal end of the indwelling tube. 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 in-vivo indwelling tube to a position that is 50% of the longitudinal length of the in-vivo indwelling tube. The medical device according to claim 1, wherein there is a space between the distal end of the inner tube member and the inner wall of the in-vivo indwelling tube in the longitudinal direction of the in-vivo indwelling tube. The medical device according to claim 3, wherein the inner diameter of the in-vivo indwelling tube in the space is greater than the outer diameter of the distal end of the inner tube member. The medical device according to claim 1, wherein the movement of the inner tube member in the distal direction in the longitudinal direction within the lumen of the in-vivo indwelling tube is restricted. The medical device further includes a barrel member having a longitudinal direction;
the outer tube member is disposed outside the inner tube member on a proximal side of a proximal end of the indwelling tube,
The medical device according to claim 1 , wherein the outer cylindrical member and the inner cylindrical member are fixed to each other at a proximal side. The medical device according to claim 1, wherein the minimum inner diameter of the in-vivo indwelling tube is smaller than the maximum outer diameter of the inner tube member in the section from the distal end of the inner tube member to a position 40 cm proximally from the distal end. The medical device according to claim 1, wherein the in-vivo indwelling tube has a thick portion in the longitudinal direction, and the thick portion is disposed distal to the distal end of the inner tube member. The medical device according to claim 1, wherein the in-vivo indwelling tube is a plastic tube stent that is placed in the bile duct or pancreatic duct. The medical device according to claim 1, wherein the in-vivo placement tube has an arcuate portion that is curved in an arc shape and a non-arc portion proximal to the arcuate portion. The medical device according to claim 10, wherein the arc portion of the in-vivo indwelling tube is configured as a closed ring in a plan view. The medical device according to claim 1, wherein the distal end of the inner tube member cannot be moved distal to the distal end of the in-vivo indwelling tube. The medical device further includes an outer tube member having a longitudinal direction and a filament;
the outer tube member is disposed outside the inner tube member proximal to a proximal end of the indwelling tube and is movable in a longitudinal direction of the inner tube member,
the outer tube member has a through hole in a side wall of a distal portion of the outer tube member,
the in-vivo indwelling tube has a through-hole in a side wall of a proximal portion of the in-vivo indwelling tube,
the thread body is configured as a ring passing through the through hole of the outer tube member and closing the ring, 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 in the ring,
2. The medical device according to claim 1, wherein the loop of the filament is passed through a through-hole of the in-vivo indwelling tube, and the inner tubular member is disposed within the loop.