Stent delivery device

Abstract

To provide a stent delivery device capable of easily achieving stent placing operation as intended.SOLUTION: A stent delivery device 100 comprises an outer tube part 10, an outer tube handle 20, an inner tube part 40, an inner shaft 50, and a shaft handle 60. A tip 40b of the inner tube part 40 is exposed from the outer tube part 10 by retreating the outer tube handle 20 to the shaft handle 60 side, and a stent 200 held in the inner tube part 40 can be placed in a body cavity. The inner shaft 50 has a retractable part 54 being a section which is in the state of being inserted into the outer tube handle 20 according to a retreat amount of the outer tube handle 20 or the state of being exposed to a base end side from the outer tube handle 20. The retractable part 54 has a plurality of markers 55 respectively formed at a plurality of positions different from each other in an axial direction of the retractable part 54.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a stent delivery device.

Background Art

[0002] As a stent delivery device used for implanting a stent into a body cavity, for example, there is one described in Patent Document 1. The stent delivery device of Patent Document 1 (the same document is described as an implant delivery device) includes a tubular main body that holds a stent (described as an implant in the same document) to be implanted into a body cavity, an operation part capable of bending the distal part of the tubular main body, and a restricting member capable of restricting the movement of the stent toward the proximal side. With the distal part of the tubular main body bent, the stent can be implanted into the body cavity by relatively moving the tubular main body with respect to the restricting member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the study by the inventor of the present application, there is still room for improvement in the structure of the stent delivery device of Cited Document 1 for realizing the intended stent implantation operation.

[0005] The present invention has been made in view of the above problems, and provides a stent delivery device capable of more reliably and easily realizing the intended stent implantation operation.

Means for Solving the Problems

[0006] According to the present invention, an outer tube part, an outer tube handle to which the proximal end part of the outer tube part is fixed, An inner tube portion that is inserted axially slidably with respect to the outer tube portion, An inner shaft that is integrated with the inner tube portion and extends from the outer tube handle toward the proximal end side, A shaft handle to which the proximal end portion of the inner shaft is fixed, and By retracting the outer tube handle together with the outer tube portion toward the shaft handle side, the tip of the inner tube portion is exposed from the outer tube portion, and the stent held by the inner tube portion can be placed in the body cavity. The inner tube portion has a stent holding portion into which the stent is externally inserted. The stent holding portion restricts the stent from being displaced axially relative to the inner tube portion as the outer tube portion moves backward or forward. The inner shaft has a projecting and retracting portion that is a section in which the inner shaft is inserted into the outer tube handle or exposed to the proximal end side of the outer tube handle according to the retraction amount of the outer tube handle. The projecting and retracting portion has a plurality of markers respectively formed at a plurality of positions different from each other in the axial direction of the projecting and retracting portion. And The plurality of markers includes a first marker. In a state where the proximal end portion of the outer tube handle is on the distal end side of the first marker, the stent holding portion is housed inside the outer tube portion. A stent delivery device is provided.

Advantages of the Invention

[0007] According to the present invention, it becomes possible to easily realize the intended stent placement operation.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Embodiments for Carrying out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 11(c). In all the drawings, the same reference numerals are assigned to the same components, and the description will be omitted as appropriate. Also, in FIGS. 1, 2, 3, 4, and 9(a), the stent 200 is shown by a two-dot chain line. Note that the various components of the stent delivery device 100 of the present invention do not necessarily exist independently. It is allowed that a plurality of components are formed as one member, one component is formed of a plurality of members, a certain component is a part of another component, a part of a certain component and a part of another component overlap, and the like. Also, hereinafter, the distal side of the stent delivery device 100 is also referred to as the tip side, and its proximal side is also referred to as the base end side. Further, the tip portion means a certain range including the distal end (the foremost end) and its periphery, and the base end portion means a certain range including the proximal end (the most proximal end) and its periphery.

[0010] As shown in FIG. 1, the stent delivery device 100 according to the present embodiment includes an outer tube portion 10, an outer tube handle 20 to which the base end portion 10a of the outer tube portion 10 is fixed, an inner tube portion 40 slidably inserted in the axial direction with respect to the outer tube portion 10, an inner shaft 50 integrated with the inner tube portion 40 and extending from the outer tube handle 20 toward the base end side, and a shaft handle 60 to which the base end portion of the inner shaft 50 is fixed. By retracting the outer tube handle 20 together with the outer tube portion 10 toward the shaft handle 60 side, the tip portion 40b of the inner tube portion 40 is exposed from the outer tube portion 10, and the stent 200 held by the inner tube portion 40 can be placed in the body cavity. The inner shaft 50 has an emerging and retracting portion 54 which is a section that is inserted into the outer tube handle 20 or exposed to the base end side of the outer tube handle 20 according to the retraction amount of the outer tube handle 20. The emerging and retracting portion 54 has a plurality of markers 55 formed at a plurality of positions different from each other in the axial direction of the emerging and retracting portion 54.

[0011] According to this embodiment, the inner shaft 50 has a plurality of markers 55 formed at a plurality of positions different from each other in the axial direction of the projecting and retracting portion 54. Thereby, the user can easily recognize the retraction amount of the outer tube handle 20 based on the positions of the plurality of markers 55. Therefore, since the progress of the deployment of the stent 200 can be grasped, the placement operation of the stent 200 as intended can be easily realized.

[0012] In a state where the stent 200 is held by the inner tube portion 40, the stent 200 is accommodated in a reduced-diameter state between the inner peripheral surface of the outer tube portion 10 and the outer peripheral surface of the inner tube portion 40. Then, with the outer tube portion 10 and the inner tube portion 40 inserted along the guide wire 300 (see FIG. 10(a) etc.) into a desired part of the body cavity, the outer tube handle 20 is retracted together with the outer tube portion 10 toward the shaft handle 60 side, and by exposing the distal end portion 40b of the inner tube portion 40 from the outer tube portion 10, the stent 200 can be deformed from the reduced-diameter state to the deployed state and placed at the desired part. More specifically, as the distal end portion 40b of the inner tube portion 40 is exposed from the outer tube portion 10, the stent 200 is also exposed from the outer tube portion 10, and the exposed portion of the stent 200 becomes the deployed state. That is, the deployment of the stent 200 progresses according to the retraction amount of the outer tube handle 20. Note that the reduced-diameter state of the stent 200 means a state in which the stent 200 is compressed in the radial direction, and the deployed state of the stent 200 means a state in which the stent 200 is expanded in the radial direction.

[0013] The outer tube portion 10 is a long hollow tubular member. As shown in FIGS. 2 and 3, the inner tube portion 40 is inserted through the inner cavity of the outer tube portion 10, and the outer tube portion 10 is slidable in the axial direction with respect to the inner tube portion 40. In the case of this embodiment, the inner diameter and the outer diameter of the outer tube portion 10 are constant regardless of the position in the axial direction. Therefore, the wall thickness of the outer tube portion 10 is constant regardless of the position in the axial direction. However, the outer diameter and the inner diameter of the outer tube portion 10 may be different according to the position in the axial direction. As shown in FIGS. 2 and 4, the outer tube portion 10 has a two-layer structure including, for example, an inner layer 14 and an outer layer 15 provided around the inner layer 14, and is configured by being laminated in the order of the inner layer 14 and the outer layer 15 from the axial center side of the outer tube portion 10. In addition, a hydrophilic layer (not shown) may be formed on the surface of the outer layer 15. The material of the hydrophilic layer is not particularly limited, and examples thereof include maleic anhydride-based polymers such as polyvinyl alcohol (PVA) and copolymers thereof, and hydrophilic resin materials such as polyvinylpyrrolidone. By doing so, the sliding resistance when the outer tube portion 10 is inserted into the body cavity of a living body can be reduced.

[0014] The inner layer 14 is the innermost layer of the outer tube portion 10 and is formed, for example, in a constant circular tubular shape regardless of the position in the axial direction of the wall thickness. The inner layer 14 is open at both ends, namely, the tip end and the base end of the outer tube portion 10. The inner layer 14 is made of, for example, a fluorine-based thermoplastic polymer resin. The fluorine-based thermoplastic polymer material is not particularly limited, and examples thereof include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and perfluoroalkoxy fluororesin (PFA). By configuring the inner layer 14 with such a fluorine-based polymer material, the sliding resistance when the inner tube portion 40 slides in the inner cavity of the outer tube portion 10 is reduced.

[0015] The outer layer 15 is the outermost layer of the outer tube portion 10. For example, most (more than half) of the wall thickness of the outer tube portion 10 is occupied by the wall thickness of the outer layer 15. The outer layer 15 is formed, for example, in a constant circular tubular shape regardless of the position in the axial direction of the wall thickness. For the outer layer 15, for example, a thermoplastic polymer material can be used. Examples of such thermoplastic polymer materials include polyimide (PI), polyamideimide (PAI), polyethylene terephthalate (PET), polyethylene (PE), polyamide (PA), nylon elastomers such as polyamide elastomer (PAE) and polyether block amide (PEBA), polyurethane (PU), ethylene-vinyl acetate resin (EVA), polyvinyl chloride (PVC), or polypropylene (PP).

[0016] The inner diameter of the outer tube portion 10 is set to be larger than the outer diameter (maximum diameter) of the inner tube portion 40. Therefore, the inner tube portion 40 can be slidably inserted into the inner cavity of the outer tube portion 10. More specifically, the inner diameter of the outer tube portion 10 is not particularly limited, but is preferably 1 mm or more and 7 mm or less. The outer diameter of the outer tube portion 10 is not particularly limited, but is preferably 1.5 mm or more and 8 mm or less. Also, the total length of the outer tube portion 10 is not particularly limited, but is preferably 500 mm or more and 2500 mm or less.

[0017] Furthermore, the outer tube portion 10 includes, for example, a reinforcing layer 16 (see FIGS. 1 and 2, etc.) formed in a mesh shape by braided metal wires. In FIGS. 1 and 8 to 11(c), the illustration of the reinforcing layer 16 is omitted. The reinforcing layer 16 is, for example, embedded in the outer layer 15 and disposed around the inner layer 14. The reinforcing layer 16 is, for example, disposed from the tip to the base end of the outer tube portion 10. The entire outer tube portion 10 is reinforced by the reinforcing layer 16. Note that the reinforcing layer 16 may be constituted by, for example, metal wires wound in a coil shape. Also, the reinforcing layer 16 may be disposed, for example, in a part of the outer tube portion 10 in the axial direction.

[0018] Also, in the case of this embodiment, an annular marker member 11 is embedded, for example, near the tip of the outer tube portion 10. The marker member 11 is made of a radiopaque material such as platinum or tungsten, for example. By using the position of the marker member 11 as an index, the position of the distal end portion 10b of the outer tube portion 10 within the body cavity can be accurately recognized under X-ray (radiation) observation. However, when the marker member 11 is not embedded in the outer tube portion 10, an inorganic filler may be mixed into the outer layer 15 of the outer tube portion 10. Examples of the inorganic filler include contrast agents such as barium sulfate and bismuth subcarbonate. By mixing the contrast agent into the outer layer 15, the X-ray contrast of the outer tube portion 10 within the body cavity can be improved.

[0019] As shown in FIG. 5, the outer tube handle 20 is, for example, a hollow member and is formed in a substantially rectangular parallelepiped shape that is long in one direction. The inner shaft 50 is inserted slidably into the outer tube handle 20, and by moving the outer tube handle 20 along the inner shaft 50 toward the shaft handle 60 side, the proximal end portion 10a of the outer tube portion 10 can also be retracted along the inner shaft 50 toward the shaft handle 60 side. Regarding the description of the outer tube handle 20, the left side in FIG. 5 is referred to as the distal end side, and the right side in FIG. 5 is referred to as the proximal end side. Also, the direction toward the distal end side and the proximal end side is referred to as the distoproximal direction. As shown in FIGS. 1 and 5, the outer tube handle 20 has, for example, a first member 22a and a second member 22b, and the outer tube handle 20 is formed by assembling the first member 22a and the second member 22b to each other. In FIG. 5, the illustration of the second member 22b is omitted, and these figures are side views in a state where the internal structure of the outer tube handle 20 can be seen. The first member 22a and the second member 22b are formed to have the same dimensions and the same outer shape as each other. The proximal end of the outer tube portion 10 is introduced into the inside of the outer tube handle 20, and the proximal end portion 10a of the outer tube portion 10 is arranged along the longitudinal direction of the outer tube handle 20.

[0020] More specifically, as shown in FIG. 5, in the case of this embodiment, a fixing ring member 19 is provided on the outer periphery of the base end portion 10a of the outer tube portion 10. The outer tube handle 20 has a housing recess 23, and the fixing ring member 19 is housed in the housing recess 23, whereby the outer tube portion 10 is fixed to the outer tube handle 20. The fixing ring member 19 is, for example, an annular member and is made of an elastic material such as silicone rubber or elastomer. The fixing ring member 19 is fixed to the outer tube portion 10, for example, by being externally fitted to the outer tube portion 10. Also, as shown in FIG. 5, a housing recess 23 having a rectangular shape in side view is formed by four wall portions standing from the inner side surface of the first member 22a. The fixing ring member 19 is housed inside the housing recess 23, and the movement of the fixing ring member 19 in the proximal-distal direction is restricted by the housing recess 23. Here, two notch-shaped portions 24c are formed in the housing recess 23. The shape of each notch-shaped portion 24c viewed in the proximal-distal direction is a semi-circular shape, and its diameter is set to a dimension slightly larger than that of the outer tube portion 10. In the outer tube portion 10, the portions on the proximal side and the distal side of the fixing ring member 19 protrude outside the housing recess 23 through the respective notch-shaped portions 24c. For example, a housing recess 23 may be similarly formed on the inner side surface of the second member 22b. In this case, a part of the fixing ring member 19 is disposed inside the housing recess 23 of the first member 22a, and the remaining part of the fixing ring member 19 is disposed inside the housing recess 23 of the second member 22b.

[0021] The outer tube handle 20 is made of, for example, a hard resin material. The hard resin material is not particularly limited, and examples include polyolefins such as polyethylene and polypropylene, polyamide, polycarbonate, and polystyrene.

[0022] As shown in FIGS. 1, 2, and 3, the inner tube portion 40 includes, for example, a relatively small-diameter thin-diameter portion 41 and a relatively large-diameter thick-diameter portion 42. Each of the small-diameter portion 41 and the large-diameter portion 42 is a long hollow tubular member. The outer diameter of the small-diameter portion 41 is set to be smaller than the inner diameter of the large-diameter portion 42. As shown in FIG. 3, a part of the small-diameter portion 41 in the axial direction is inserted into the inner cavity of the large-diameter portion 42. Also, the total length of the small-diameter portion 41 is set to be longer than the total length of the large-diameter portion 42. And with reference to the large-diameter portion 42, the small-diameter portion 41 protrudes toward the distal end side from the opening on the distal end side of the large-diameter portion 42 and also protrudes toward the proximal end side from the opening on the proximal end side of the large-diameter portion 42. Here, in the small-diameter portion 41, the portion on the distal end side of the small-diameter portion 41 from the distal end of the large-diameter portion 42 constitutes an arrangement section 41a where the stent 200 is arranged. The stent 200 is held by the small-diameter portion 41 of the inner tube portion 40 while being externally inserted into the arrangement section 41a in the small-diameter portion 41. Also, in the small-diameter portion 41, the portion on the proximal end side of the small-diameter portion 41 from the proximal end of the large-diameter portion 42 is inserted into the inner cavity of the inner shaft 50. More specifically, the distal end portion of the inner shaft 50 is inserted into the opening on the proximal end side of the large-diameter portion 42, and the inner cavity of the large-diameter portion 42 and the inner cavity of the inner shaft 50 communicate with each other. And the small-diameter portion 41 is inserted across the inner cavity of the large-diameter portion 42 and the inner cavity of the inner shaft 50, and further reaches inside the shaft handle 60.

[0023] More specifically, for example, an endoscope visual recognition marker 46 is provided at the distal end portion of the large-diameter portion 42. Thus, in the small-diameter portion 41, the portion on the distal end side of the small-diameter portion 41 from the endoscope visual recognition marker 46 is the arrangement section 41a, and the entire stent 200 is externally inserted into the arrangement section 41a. That is, the endoscope visual recognition marker 46 is arranged on the proximal end side of the stent 200. Therefore, the user can easily grasp the position of the stent 200 based on the position of the endoscope visual recognition marker 46 as an index in the captured image by the endoscope. More specifically, when using the stent delivery device 100, as shown in FIG. 8, in the inner tube portion 40, at least the portion on the distal end side of the inner tube portion 40 from the endoscope visual recognition marker 46 is in a state of being exposed from the distal end of the insertion portion of the endoscope 400. Further, the tip of the endoscope visual marker 46 is fixed to the small-diameter portion 41. More specifically, an adhesive 42a is applied in a circumferential shape at the tip of the endoscope visual marker 46 and at a location corresponding to the tip on the outer peripheral surface of the small-diameter portion 41. Thereby, the small-diameter portion 41 is fixed to the endoscope visual marker 46 and thus to the large-diameter portion 42. The proximal end of the endoscope visual marker 46 is connected to the tip side of the large-diameter portion 42, and the lumen of the endoscope visual marker 46 and the lumen of the large-diameter portion 42 communicate with each other. Therefore, the small-diameter portion 41 is inserted through the lumen of the endoscope visual marker 46 and the lumen of the large-diameter portion 42. The outer diameter of the endoscope visual marker 46 is set to be substantially equal to the outer diameter of the large-diameter portion 42. The endoscope visual marker 46 is constituted by, for example, a resin tube that is a separate member from the large-diameter portion 42 and is colored in a color different from that of the large-diameter portion 42. Further, the outer tube portion 10 is constituted by, for example, a transparent (transparent to visible light) resin material. For this reason, the user can visually recognize the endoscope visual marker 46 through the outer tube portion 10. Note that the endoscope visual marker 46 may be formed, for example, by applying ink to the tip portion of the large-diameter portion 42, or may be constituted by an X-ray impermeable material such as platinum or tungsten.

[0024] Also, a tip chip 43 (see FIGS. 1 and 4) is provided at the tip of the small-diameter portion 41. The tip chip 43 is formed, for example, in a conical shape that gradually decreases in diameter toward the tip side. The proximal end portion of the tip chip 43 is connected to the tip portion of the small-diameter portion 41, and the lumen of the tip chip 43 and the lumen of the small-diameter portion 41 communicate with each other. When inserting the stent delivery device 100 into the body cavity, a guide wire 300 (see FIGS. 9(a) etc.) that has been previously inserted into the body cavity is inserted into the lumen of the inner tube portion 40 through the opening on the tip side of the tip chip 43. Thereby, the outer tube portion 10 and the inner tube portion 40 can be inserted into the body cavity along the guide wire 300. In FIGS. 9(a) to 10(c), the guide wire 300 is shown by a dashed line. In the case of this embodiment, the proximal end of the tip chip 43 and the distal end of the outer tube portion 10 face each other. And as shown in FIG. 4, the outer diameter of the tip chip 43 is set to be substantially equal to or slightly larger than the outer diameter of the outer tube portion 10, and the inner diameter of the tip chip 43 is set to be smaller than the inner diameter of the outer tube portion 10. For this reason, for example, when the outer tube handle 20 is advanced toward the tip chip 43 together with the outer tube portion 10, the distal end face of the outer tube portion 10 abuts against the proximal end face of the tip chip 43, thereby restricting further advancement of the outer tube portion 10. Therefore, further advancement of the outer tube handle 20 integrated with the outer tube portion 10 is also restricted. In the following description, the state where the distal end face of the outer tube portion 10 abuts against the proximal end face of the tip chip 43 (see FIG. 1 etc.) is set as the initial state of the stent delivery device 100.

[0025] Furthermore, in the case of this embodiment, a stent holding portion 48 (see FIG. 1 etc.) is provided on the outer periphery of the small-diameter portion 41. The stent holding portion 48 is formed to have a larger diameter than the small-diameter portion 41. The stent holding portion 48 holds the stent 200 in the arrangement section 41a, and the stent holding portion 48 restricts the displacement of the stent 200 with respect to the arrangement section 41a as the outer tube portion 10 retreats or advances. More specifically, the stent holding portion 48 is, for example, a resin tube and is externally fitted to the small-diameter portion 41. Also, an adhesive (not shown) is applied, for example, to the outer peripheral surface of the stent holding portion 48 and the vicinity of the arrangement region of the stent holding portion 48 in the arrangement section 41a, and the stent holding portion 48 is fixed to the arrangement section 41a by the adhesive. The inner diameter of the stent holding portion 48 is set to be substantially equal to the outer diameter of the small-diameter portion 41. The outer diameter of the stent holding portion 48 is set to be smaller than the inner diameter of the outer tube portion 10 and larger than the inner diameter of the stent 200 in the reduced-diameter state. The stent 200 is held between the inner peripheral surface of the outer tube portion 10 and the outer peripheral surface of the small-diameter portion 41 with a part of the stent 200 in the longitudinal direction thereof being externally inserted into the stent holding portion 48. More specifically, in the stent 200, the portion externally inserted into the stent holding portion 48 is in a state of being sandwiched between the inner peripheral surface of the outer tube portion 10 and the outer peripheral surface of the stent holding portion 48, whereby the stent 200 is restricted from being displaced axially relative to the arrangement section 41a as the outer tube portion 10 moves backward or forward. The length dimension (dimension in the axial direction) of the stent holding portion 48 is not particularly limited, but is preferably set appropriately according to the length dimension of the stent 200.

[0026] The small-diameter portion 41 is made of, for example, a fluorine-based thermoplastic polymer resin. The fluorine-based thermoplastic polymer material is not particularly limited, and may be polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), perfluoroalkoxy fluororesin (PFA), or the like. By forming the small-diameter portion 41 with such a fluorine-based polymer material, the sliding resistance when the guide wire 300 slides in the lumen of the small-diameter portion 41 is reduced. In addition, the large-diameter portion 42 is integrally formed entirely of, for example, a thermoplastic polymer material. Examples of this thermoplastic polymer material include polyimide (PI), polyamideimide (PAI), polyethylene terephthalate (PET), polyethylene (PE), polyamide (PA), polyamide elastomer (PAE), polyether block amide (PEBA) and other nylon elastomers, polyurethane (PU), ethylene-vinyl acetate resin (EVA), polyvinyl chloride (PVC), or polypropylene (PP). Note that the large-diameter portion 42 may be, for example, a single tubular body formed by connecting tubular members formed separately from each other.

[0027] The outer diameter of the small-diameter portion 41 is not particularly limited, but is preferably 0.1 mm or more and 2 mm or less. The inner diameter of the small-diameter portion 41 is not particularly limited, but is preferably 0.05 mm or more and 1 mm or less. Further, the total length of the small-diameter portion 41 is not particularly limited, but is preferably 500 mm or more and 3000 mm or less. The outer diameter of the large-diameter portion 42 is not particularly limited, but is preferably 1 mm or more and 6 mm or less. The inner diameter of the large-diameter portion 42 is not particularly limited, but is preferably 0.5 mm or more and 4 mm or less. Further, the total length of the large-diameter portion 42 is not particularly limited, but is preferably 500 mm or more and 2500 mm or less.

[0028] The inner shaft 50 is formed, for example, in a tubular shape that is long in one direction. The distal end portion of the inner shaft 50 is press-fitted and fixed to the proximal end portion of the large-diameter portion 42, whereby the large-diameter portion 42 and the inner shaft 50 are fixed to each other. Note that the large-diameter portion 42 and the inner shaft 50 may be fixed to each other by, for example, adhesion or fusion. In the case of the present embodiment, a section of the inner shaft 50 that is exposed on the proximal end side of the outer tube handle 20 in the initial state constitutes the projecting and retracting portion 54. The shaft handle 60 is formed, for example, in a cylindrical shape, and the shaft handle 60 is connected to the proximal end side of the large-diameter portion 42 and has a lumen that is continuous with the lumen of the large-diameter portion 42. When using the stent delivery device 100, for example, physiological saline, a contrast agent, or the like can be injected into the lumen of the small-diameter portion 41 through the opening on the proximal end side of the shaft handle 60.

[0029] The inner shaft 50 is made of, for example, a metal material such as stainless steel (SUS). Further, the shaft handle 60 is made of, for example, a resin material such as polyurethane or polyamide.

[0030] The outer diameter (maximum diameter) of the inner shaft 50 is not particularly limited, but is preferably 1 mm or more and 6 mm or less. The inner diameter of the inner shaft 50 is not particularly limited, but is preferably 0.5 mm or more and 3 mm or less. Further, the total length of the inner shaft 50 is not particularly limited, but is preferably 30 mm or more and 500 mm or less.

[0031] Here, as described above, the protruding / retracting portion 54 has a plurality of markers 55 respectively formed at a plurality of positions different from each other in the axial direction of the protruding / retracting portion 54. In the case of this embodiment, as shown in FIG. 1, the plurality of markers 55 include a first marker 56, a second marker 57 formed on the proximal side of the first marker 56, and a third marker 58 formed on the proximal side of the second marker 57. The first marker 56 indicates, for example, that the outer tube handle 20 is at a position corresponding to the start position of the deployment of the stent 200. As shown in FIG. 9(a), in this state, at least the tip of the stent 200 is exposed from the outer tube portion 10, and the deployment of the exposed portion has started. The second marker 57 indicates, for example, that the outer tube handle 20 is at a position corresponding to the limit position of the re-storage of the stent 200. As shown in FIG. 9(b), in this state, at least the portion of the stent 200 on the tip side of at least the stent holding portion 48 is exposed from the outer tube portion 10, and the deployment of the exposed portion has started. The third marker 58 indicates, for example, that the outer tube handle 20 is at a position corresponding to the fully deployed position of the stent 200. As shown in FIG. 9(c), in this state, the entire stent 200 is exposed from the outer tube portion 10, and the deployment of the stent 200 is completed. The user can grasp the stepwise deployment state of the stent 200 by using the position of the outer tube handle 20 with respect to these three markers 55 as an index.

[0032] More specifically, as shown in FIG. 1, in the initial state of the stent delivery device 100, the entire protruding / retracting portion 54 of the inner shaft 50 is exposed from the proximal end side of the outer tube handle 20. Accordingly, the first marker 56 to the third marker 58 are also exposed from the proximal end side of the outer tube handle 20. Then, from the initial state, as shown in FIGS. 9(a) and 10(b), by retracting the outer tube handle 20 toward the shaft handle 60 until the proximal end portion of the outer tube handle 20 approaches the tip of the first marker 56, the distal end portion 10b of the outer tube portion 10 can be slightly retracted with respect to the inner tube portion 40, and the distal end side portion in the arrangement section 41a of the reduced-diameter portion 41 can be exposed from the outer tube portion 10. Thereby, the distal end portion of the stent 200 can be slightly exposed from the outer tube portion 10, and the deployment of the stent 200 can be started. Next, from the state shown in FIGS. 9(a) and 10(b), as shown in FIGS. 9(b) and 10(c), by retracting the outer tube handle 20 toward the shaft handle 60 until the proximal end portion of the outer tube handle 20 approaches the tip of the second marker 57, the distal end portion 10b of the outer tube portion 10 can be further retracted with respect to the inner tube portion 40, and a longer range of the arrangement section 41a in the reduced-diameter portion 41 can be exposed from the outer tube portion 10. Thereby, a longer range of the distal end portion of the stent 200 can be exposed from the outer tube portion 10, and the portion of the stent 200 exposed from the outer tube portion 10 can be locally brought into a deployed state. Here, in a state where the proximal end portion of the outer tube handle 20 is on the distal end side of the tip of the second marker 57, the stent holding portion 48 is housed inside the outer tube portion 10. That is, the stent 200 is in a state of being sandwiched between the outer peripheral surface of the stent holding portion 48 and the inner peripheral surface of the outer tube portion 10. For this reason, when the outer tube handle 20 is advanced, the outer tube portion 10 advances relative to the stent 200, and the stent 200 can be rehoused in the outer tube portion 10. Thereby, for example, even if the deployment of the stent 200 is inadvertently started at a position other than the desired position in the body cavity, the position of the stent 200 in the body cavity can be adjusted together with the outer tube portion 10 and the inner tube portion 40 by rehousing the stent 200 in the outer tube portion 10. Subsequently, from the states shown in FIGS. 9(b) and 10(b), as shown in FIGS. 9(c) and 10(c), the proximal end portion of the outer tube handle 20 is retracted toward the shaft handle 60 until it approaches the tip of the third marker 58, so that the tip portion 10b of the outer tube portion 10 is retracted to a position closer to the proximal end side than the endoscope viewing marker 46, and the entire arrangement section 41a of the stent 200 in the reduced-diameter section 41 and the stent holding section 48 can be exposed from the outer tube portion 10. As a result, the entire stent 200 is exposed from the outer tube portion 10, the stent 200 is released from the state of being sandwiched between the outer peripheral surface of the stent holding section 48 and the inner peripheral surface of the outer tube portion 10, and the deformation of the stent 200 from the reduced-diameter state to the deployed state can be completed.

[0033] Here, in the case of the present embodiment, the stent delivery device 100 further includes a switching operation section 30 (hereinafter simply referred to as a switching operation) capable of switching between a state in which the advancement and retraction of the outer tube handle 20 with respect to the inner shaft 50 is restricted and a state in which the advancement and retraction of the outer tube handle 20 with respect to the inner shaft 50 is possible. Thereby, since the advancement and retraction of the outer tube handle 20 with respect to the inner shaft 50 can be appropriately restricted, it is possible to prevent the outer tube handle 20 from being inadvertently moved, and it becomes easy to retract the outer tube handle 20 toward the shaft handle 60 at a desired timing and retraction amount. Therefore, it is possible to more reliably and easily realize the intended placement operation of the stent 200.

[0034] As shown in FIGS. 7(a) and 7(b), the switching operation section 30 includes, for example, a ring member 33 formed of an elastic body and through which the inner shaft 50 is inserted, a housing member 35 through which the inner shaft 50 is inserted and which houses the ring member 33, and a screwing member 37 through which the inner shaft 50 is inserted and which is screwed to the housing member 35. In the case of the present embodiment, by screwing the screwing member 37 into the housing member 35 and compressing the ring member 33 between the housing member 35 and the screwing member 37, the inner shaft 50 is held by the ring member 33, and the advancement and retraction of the switching operation section 30 with respect to the inner shaft 50 is restricted.

[0035] The ring member 33 is formed, for example, in a cylindrical shape with the proximal end direction as the axial direction, and the inner shaft 50 is inserted into the inner cavity of the ring member 33. The inner diameter of the ring member 33 in the natural state is set to be approximately equal to the outer diameter of the inner shaft 50, for example. The elastic body constituting the ring member 33 is not particularly limited, and examples thereof include elastic materials such as silicone rubber and elastomer.

[0036] The housing member 35 is formed in a cylindrical shape with the proximal end direction as the axial direction. The inner shaft 50 is inserted into the inner cavity of the housing member 35 and is slidable in the axial direction of the housing member 35 with respect to the housing member 35. More specifically, as shown in FIG. 7(a), the housing member 35 includes, for example, a main body portion 35a into which the screwing member 37 is screwed, and an operation receiving portion 35b that receives a switching operation. Each of the main body portion 35a and the operation receiving portion 35b is formed in a cylindrical shape with the proximal end direction as the axial direction. The proximal end side of the main body portion 35a is connected to the distal end side of the operation receiving portion 35b. The main body portion 35a and the operation receiving portion 35b are arranged coaxially with each other, and the inner cavity of the main body portion 35a and the inner cavity of the operation receiving portion 35b communicate with each other. The inner diameter of the main body portion 35a is smaller than the inner diameter (maximum diameter) of the operation receiving portion 35b, and the outer diameter of the main body portion 35a is smaller than the outer diameter of the operation receiving portion 35b. Also, the inner cavity of the proximal end portion of the operation receiving portion 35b is formed to have a smaller diameter than the inner cavity of the other portions, and the inner cavity of the operation receiving portion 35b includes a large-diameter portion and a small-diameter portion. The ring member 33 is accommodated in the large-diameter portion of the inner cavity of the operation receiving portion 35b. A part of the inner peripheral surface of the operation receiving portion 35b constitutes a stepped surface facing the distal end side at the boundary between the large-diameter portion and the small-diameter portion of the inner cavity of the operation receiving portion 35b. The shape of the stepped surface viewed in the axial direction of the operation receiving portion 35b is annular, and the stepped surface faces the front end surface of the ring member 33. Also, as shown in FIG. 5, on the outer peripheral surface of the operation receiving portion 35b, for example, a plurality of grooves extending in the axial direction thereof are intermittently arranged in the circumferential direction of the operation receiving portion 35b, and portions between adjacent ones of the plurality of grooves constitute a plurality of concavo-convex portions alternately arranged in the circumferential direction.

[0037] The screwing member 37 is formed in a cylindrical shape with the tip base end direction as the axial direction. The inner shaft 50 is inserted into the inner cavity of the screwing member 37 and is slidable in the axial direction of the screwing member 37 with respect to the screwing member 37. More specifically, as shown in FIGS. 7(a) and 7(b), the screwing member 37 includes, for example, a screwing portion 37a screwed to the housing member 35, a flange portion 37c formed on the tip side of the screwing portion 37a, and an insertion portion 37b inserted into the inner cavity of the main body portion 35a of the housing member 35. Each of the screwing portion 37a and the insertion portion 37b is formed in a cylindrical shape with the tip base end direction as the axial direction and is coaxially arranged with each other. The base end of the screwing portion 37a is connected to the tip of the insertion portion 37b. Also, the inner cavity of the screwing portion 37a and the inner cavity of the insertion portion 37b communicate with each other. The outer diameter of the screwing portion 37a is set to a dimension larger than the outer diameter of the insertion portion 37b, for example, and the inner diameter of the screwing portion 37a is set to a dimension substantially equal to the inner diameter of the insertion portion 37b, for example. As shown in FIG. 7(a), the outer shape of the flange portion 37c viewed in the axial direction is, for example, a regular hexagonal shape, the outer peripheral surface of the flange portion 37c is composed of six surfaces, and the six surfaces are formed on surfaces orthogonal to the axial direction. The dimension of the flange portion 37c in the radial direction is larger than the outer diameter of the screwing portion 37a.

[0038] In the case of this embodiment, the screwing member 37 is screwed into the housing member 35 from the tip side. More specifically, a thread is formed on the outer peripheral surface of the screwing portion 37a, and the screwing portion 37a serves as a male thread portion. Also, a thread is formed on the inner peripheral surface of the main body portion 35a, and the main body portion 35a serves as a female thread portion. By screwing the female thread portion and the male thread portion together, the screwing member 37 and the housing member 35 are interconnected. And the ring member 33 is disposed between the end face on the proximal end side of the screwing portion 37a and the stepped surface of the operation receiving portion 35b. Also, the inner shaft 50 is inserted through the inner cavities of the screwing member 37 and the housing member 35. The inner shaft 50 protrudes toward the distal end side from the opening on the distal end side of the screwing member 37 and also protrudes toward the proximal end side from the opening on the proximal end side of the housing member 35.

[0039] Each of the housing member 35 and the screwing member 37 is made of, for example, a hard resin material. This resin material is not particularly limited, and examples include polyolefins such as polyethylene and polypropylene, polyamide, polycarbonate, polystyrene, and the like. The housing member 35 and the screwing member 37 may be made of the same type of resin material as each other, or may be made of different resin materials from each other.

[0040] Here, inside the outer tube handle 20, a pair of holding portions 25 for holding the screwing member 37 and a housing portion 26 for housing the housing member 35 are respectively formed. The pair of holding portions 25 restricts the rotation of the screwing member 37 with respect to the outer tube handle 20, while the housing portion 26 allows the rotation of the housing member 35 with respect to the outer tube handle 20. As shown in FIG. 5, the pair of holding portions 25 are disposed, for example, on the distal end side of the housing portion 26. And in the case of this embodiment, by rotating the housing member 35 out of the screwing member 37 and the housing member 35, the screwing member 37 moves in the proximal-distal direction.

[0041] More specifically, each of the pair of holding portions 25 is constituted by a pair of flat plate-shaped wall portions erected on the inner surface of the first member 22a. Each of the pair of wall portions is disposed with the flange portion 37c of the screwing member 37 interposed therebetween. More specifically, among the six surfaces constituting the outer peripheral surface of the flange portion 37c, any one surface is in surface contact with one of the pair of wall portions, and a surface parallel to the surface is in surface contact with the other of the pair of wall portions. Therefore, while the movement of the screwing member 37 in the proximal direction is allowed, the screwing member 37 is held by the pair of holding portions 25 in a state where the rotation of the screwing member 37 is restricted. However, in the case of the present embodiment, on the inner surface of the first member 22a, a regulating plate 27 for restricting the movement of the screwing member 37 to the distal side with respect to the holding portion 25 is formed between the pair of holding portions 25. Thereby, the movement of the screwing member 37 to the proximal side with respect to the regulating plate 27 is restricted. Note that the shape of the flange portion 37c viewed in the proximal-distal direction is not particularly limited, and any shape may be used as long as its outer peripheral surface has a pair of surfaces facing each other. Further, such a pair of holding portions 25 may be formed, for example, at positions corresponding to the holding portions 25 of the first member 22a on the inner surface of the second member.

[0042] In the case of the present embodiment, four wall portions are erected on the inner surface of the first member 22a. A frame-shaped accommodating portion 26 having a substantially rectangular shape in side view is formed by the aggregate of these four wall portions. Further, two notch-shaped portions 26a are formed in the accommodating portion 26. One of the two notch-shaped portions 26a allows the passage of the distal end side of the main body portion 35a, and the other allows the passage of the proximal end side of the inner shaft 50. Thereby, the accommodating member 35 can rotate about the axis with respect to the outer tube handle 20 while being accommodated inside the accommodating portion 26. Then, the user can perform a switching operation, for example, by rotating the operation receiving portion 35b about the axis. Note that such an accommodating portion 26 may be formed, for example, at a portion corresponding to the accommodating portion 26 of the first member 22a on the inner surface of the second member 22b. Here, in each of the first member 22a and the second member 22b, an opening 22c (see FIG. 1) is formed in a portion corresponding to the operation receiving portion 35b to communicate the internal space of the outer tube handle 20 and the outside of the outer tube handle 20 with each other. And at least a part in the circumferential direction of the operation receiving portion 35b is accessible to the user's finger from the outside of the outer tube handle 20 through the opening 22c. Note that a part of the operation receiving portion 35b may or may not protrude to the outside of the outer tube handle 20 through the opening 22c. The opening 22c is formed, for example, in a substantially rectangular shape in side view.

[0043] More specifically, by an operation of rotating the operation receiving portion 35b of the housing member 35 relative to the outer tube handle 20 in one direction in the circumferential direction (hereinafter, closing operation), it is possible to switch to a state in which the advance and retreat of the outer tube handle 20 with respect to the inner shaft 50 is restricted. Along with the closing operation, the screwing member 37 screws into the housing member 35 and screws forward from the tip side toward the base end side. At this time, with the screwing forward of the screwing member 37, in the tip-base end direction, the step surface of the main body portion 35a of the housing member 35 and the end surface on the base end side of the screwing portion 37a of the screwing member 37 approach each other. As a result, the ring member 33 disposed between the step surface of the main body portion 35a and the end surface on the base end side of the screwing portion 37a is pressed by these surfaces and elastically deformed, and is in a state of being compressed in the axial direction, and the inner diameter of the ring member 33 is reduced. Then, by further performing the closing operation, the inner shaft 50 can be brought into a state of being circumferentially tightened by the ring member 33 compressed in the tip-base end direction. Also, by an operation of rotating the operation receiving portion 35b of the housing member 35 relative to the screwing member 37 in the other direction in the circumferential direction (the direction opposite to the rotation direction in the closing operation) (hereinafter, opening operation), it is possible to switch to a state in which the advance and retreat of the outer tube handle 20 with respect to the inner shaft 50 is possible. Along with the opening operation, the screwing member 37 moves toward the tip side, the ring member 33 is released from the compressed state, and the switching operation portion 30 can advance and retreat with respect to the inner shaft 50. Here, as described above, a regulating plate 27 is disposed between a pair of holding portions 25 that hold the screwing member 37. By the screwing member 37 coming into contact with the regulating plate 27, it is regulated that the screwing between the housing member 35 and the screwing member 37 is completely released. Note that the screwing direction of the screwing member 37 is not limited to the tip side to the base end side, and the screwing member 37 may be configured to screw from the base end side toward the tip side. In this case, in the tip-base end direction, the positional relationship between the housing member 35 and the screwing member 37 is reversed.

[0044] Here, in the case of this embodiment, due to the thickness of the marker 55, a step 52 (see FIGS. 6(a) to 6(c)) is formed on the outer peripheral surface of the inner shaft 50 at the location where the marker 55 is formed, and the outer tube handle 20 has a friction generating portion 32 that generates mutually different frictional resistances when the location where the marker 55 is formed on the inner shaft 50 passes through and when the location where the marker 55 is not formed passes through. Thereby, when the outer tube handle 20 is retracted toward the shaft handle 60 side, the user can easily recognize the retraction amount of the outer tube handle 20, for example, based on the difference in the frictional feeling generated by the friction generating portion 32. Thus, for example, it is also possible to easily grasp the progress of the deployment of the stent 200 based on such a frictional feeling without relying on visual information. In the case of this embodiment, as an example, the ring member 33 is the friction generating portion 32. More specifically, the outer diameter of the inner shaft 50 is set to be substantially equal to or slightly larger than the inner diameter of the ring member 33 in the natural state. For this reason, when the ring member 33 slides with respect to the inner shaft 50, frictional resistance is generated by the contact between the outer peripheral surface of the inner shaft 50 and the inner peripheral surface of the ring member 33. Note that the frictional resistance referred to here means the frictional resistance generated when the ring member 33 is slid with respect to the inner shaft 50 in a state where the outer tube handle 20 can advance and retreat with respect to the inner shaft 50. Then, as shown in FIGS. 6(a) to 6(c), in the inner shaft 50, the outer diameter of the formation location of the marker 55 is, for example, larger than the outer diameter of the non-formation location of the marker 55. Therefore, the frictional resistance generated when the formation location of the marker 55 in the inner shaft 50 passes through the inner cavity of the ring member 33 is greater than the frictional resistance generated when the non-formation location of the marker 55 in the inner shaft 50 passes through the inner cavity of the ring member 33. More specifically, as shown in FIG. 11(a), in a state where the first marker 56 is located in the inner cavity of the ring member 33, the stent 200 has started to deform into the deployed state while being re-closable inside the outer tube portion 10. That is, the user can grasp that the outer tube handle 20 is on the proximal side of the position corresponding to the start position of the deployment of the stent 200 and on the distal side of the position corresponding to the limit position of the re-closure of the stent 200 based on the frictional feeling generated when the first marker 56 passes through the inner cavity of the ring member 33. Also, as shown in FIG. 11(b), in a state where the second marker 57 is located in the inner cavity of the ring member 33, the stent 200 has further deployed from the re-closable state while not being in the fully deployed state. That is, the user can grasp that the outer tube handle 20 is on the proximal side of the position corresponding to the limit position of the re-closure of the stent 200 and on the distal side of the position corresponding to the fully deployed position of the stent 200 based on the frictional feeling generated when the second marker 57 passes through the inner cavity of the ring member 33. Then, as shown in FIG. 11(c), in a state where the third marker 58 is located in the inner cavity of the ring member 33, the stent 200 is in the fully deployed state. That is, the user can grasp that the outer tube handle 20 is on the proximal side of the position corresponding to the fully deployed position of the stent 200 based on the frictional feeling generated when the third marker 58 passes through the inner cavity of the ring member 33. In FIGS. 11(a) to 11(c), for the sake of convenience, illustration of a plurality of grooves formed on the outer peripheral surface of the operation receiving portion 35b is omitted. Further, in FIGS. 11(a) to 11(c), for the sake of convenience, the formation locations of the markers 55 arranged in the inner cavity of the ring member 33 are shaded with dots, but actually, the markers 55 are located inside the outer tube portion 10.

[0045] Furthermore, for at least two of the plurality of markers 55 arranged adjacent to each other, it is preferable that the frictional resistances generated by the friction generating portion 32 are different from each other. By doing so, when the outer tube handle 20 is retracted toward the shaft handle 60 side, the user can recognize to what stage the stent 200 has been deployed based on the difference in the frictional feeling generated by the friction generating portion 32. More specifically, in the case of the present embodiment, the first marker 56 to the third marker 58 are formed, for example, by applying ink. Note that the formation range of the first marker 56 to the third marker 58 in the circumferential direction may be the entire circumference or a part thereof on the outer peripheral surface of the inner shaft 50 in the circumferential direction. And in the case of the present embodiment, by changing the application amounts of the ink forming the first marker 56 to the third marker 58 from each other, the thicknesses of the respective markers 55 are made different from each other. The magnitude relationship and the arrangement order of the thicknesses of the first marker 56 to the third marker 58 are not particularly limited. As an example, the thickness (T1 shown in FIG. 6(a)) of the first marker 56 is, for example, larger than the thickness (T2 shown in FIG. 6(b)) of the second marker 57. Also, the thickness T2 of the second marker 57 is, for example, larger than the thickness (T3 shown in FIG. 6(c)) of the third marker 58. Further, the marker 55 may be, for example, a rough surface formed with a plurality of minute irregularities. In this case, for at least two markers 55 arranged adjacent to each other among the plurality of markers 55, at least one of the conditions such as the height or number of the irregularities of the rough surface, the formation range of the rough surface in the circumferential direction, and the coarseness of the rough surface of the rough surface is made different, so that the frictional resistance generated in the friction generating portion 32 is preferably configured to be different from each other. Further, the marker 55 may be formed of materials having different coefficients of friction from each other, whereby the frictional resistance generated in the friction generating portion 32 may be configured to be different from each other.

[0046] Further, the plurality of markers 55 include, for example, markers 55 having different appearances from each other. Thereby, the user can easily identify each marker 55. More specifically, in the case of the present embodiment, the colors of the inks forming the first marker 56 and the third marker 58 are different from the color of the ink forming the second marker 57. The color of the ink is not particularly limited. As an example, the colors of the inks of the first marker 56 and the third marker 58 are black, and the color of the ink of the second marker 57 is yellow. In FIGS. 1 and 10(a) to 11(c), the formation locations of the first marker 56 to the third marker 58 are shaded with dots, and the shading of the second marker 57 is finer than the shading of the first marker 56 and the third marker 58. However, for example, all of the markers 55 may be formed of inks having different colors from each other, or may be formed of inks having the same color from each other. When each marker 55 is formed of an ink having the same color from each other, for example, it is preferable that the length dimensions of each marker 55, the formation range in the circumferential direction, etc. are different from each other. Thereby, each marker 55 can be made into a marker 55 having a different appearance from each other.

[0047] Hereinafter, an example of the usage method of the stent delivery device 100 of the present embodiment will be described. Hereinafter, as an example, an example in which the stent delivery device 100 is used in a procedure for placing the stent 200 inside a bile duct (not shown) will be described. It should be noted that the tip of the insertion portion of the endoscope 400 (see FIG. 8) is previously placed near the duodenal papilla (Farter papilla) inside the duodenum (not shown), and a needle hole is formed in the bile duct (not shown), and the tip of the guide wire 300 is anchored (locked) to the needle hole. The description will be made from this state. First, the stent delivery device 100 is introduced along the guide wire 300. More specifically, the narrow-diameter portion 41 of the inner tube portion 40 is externally inserted into the guide wire 300, and while sliding the inner tube portion 40 from the proximal end side to the distal end side along the axial direction of the guide wire, the inner tube portion 40 and the outer tube portion 10 are fed to the above-mentioned needle hole. At this time, the switching operation portion 30 restricts the advance and retreat of the outer tube handle 20 with respect to the inner shaft 50. Next, when the arrangement section 41a of the stent 200 in the inner tube portion 40 is inserted into the bile duct, the stent 200 is placed. More specifically, first, the switching operation portion 30 switches to a state where the outer tube handle 20 can advance and retreat with respect to the inner shaft 50. Then, while gripping the shaft handle 60 with one hand, the outer tube handle 20 is retracted toward the shaft handle 60 together with the outer tube portion 10 with the other hand, so that the distal end portion 40b of the inner tube portion 40 is exposed from the outer tube portion 10. Then, until the proximal end portion of the outer tube handle 20 is positioned in front of the third marker 58, that is, until the entire arrangement section 41a of the stent 200 in the inner tube portion 40 is exposed from the outer tube portion 10, by retracting the outer tube handle 20, the entire stent 200 changes from the reduced-diameter state to the expanded state. Thereby, the stent 200 is placed inside the bile duct. Here, even if the deployment of the stent 200 is unintentionally started at a position other than the desired position in the body cavity, as described above, when the proximal end portion of the outer tube handle 20 is on the distal end side of the distal end of the second marker 57, the stent 200 can be rehoused in the outer tube portion 10 by advancing the outer tube handle 20. Then, with the outer tube handle 20 advanced together with the outer tube portion 10 until the tip of the outer tube portion 10 abuts against the tip chip, the switching operation unit 30 switches again to a state in which the forward and backward movement of the outer tube handle 20 with respect to the inner shaft 50 is restricted. In this state, the inner tube portion 40 and the outer tube portion 10 are removed from the body cavity, and the guide wire 300 is also removed from the body cavity.

[0048] The present invention is not limited to the above-described embodiments, and includes various modifications, improvements, and the like as long as the object of the present invention is achieved.

[0049] This embodiment includes the following technical ideas. (1) An outer tube portion, an outer tube handle to which the proximal end portion of the outer tube portion is fixed, an inner tube portion slidably inserted axially with respect to the outer tube portion, an inner shaft integrated with the inner tube portion and extending from the outer tube handle toward the proximal end side, a shaft handle to which the proximal end portion of the inner shaft is fixed, and by retracting the outer tube handle together with the outer tube portion toward the shaft handle side, the tip portion of the inner tube portion is exposed from the outer tube portion, and a stent held by the inner tube portion can be placed in the body cavity. The inner shaft has a protruding and retracting portion which is a section in which the inner shaft is inserted into the outer tube handle or exposed on the proximal end side of the outer tube handle according to the retraction amount of the outer tube handle. The protruding and retracting portion has a plurality of markers respectively formed at a plurality of positions different from each other in the axial direction of the protruding and retracting portion, and is a stent delivery device. (2) Due to the thickness of the marker, a step is formed on the outer peripheral surface of the inner shaft at the location where the marker is formed. The outer tube handle has a friction generating portion that generates different frictional resistances when the location where the marker is formed on the inner shaft passes and when the location where the marker is not formed passes, and is the stent delivery device according to (1). (3) For at least two markers among the plurality of markers that are arranged adjacent to each other, the frictional resistance generated by the friction generating portion is different from each other. The stent delivery device according to (2). (4) The outer tube handle includes a switching operation portion capable of switching between a state in which the advancement and retraction of the outer tube handle with respect to the inner shaft are restricted and a state in which the advancement and retraction of the outer tube handle with respect to the inner shaft are possible. The switching operation portion is constituted by an elastic body and a ring member through which the inner shaft is inserted, a housing member through which the inner shaft is inserted and that houses the ring member, a screwing member through which the inner shaft is inserted and that is screwed to the housing member, and has By screwing the screwing member into the housing member and compressing the ring member between the housing member and the screwing member, the advancement and retraction of the switching operation portion with respect to the inner shaft are restricted. The stent delivery device according to (2) or (3), wherein the ring member is the friction generating portion. (5) The plurality of markers include markers that look different from each other. The stent delivery device according to any one of (1) to (4).

Explanation of Reference Numerals

[0050] 10 Outer tube portion 10a Base end portion 10b Tip end portion 11 Marker member 14 Inner layer 15 Outer layer 16 Reinforcing layer 19 Fixing ring member 20 Outer tube handle 22a First member 22b Second member 22c Opening 23 Housing recess 24c Notch-shaped portion 25 Holding part 26 Accommodating part 26a Notch-shaped part 27 Regulation plate 30 Switching operation part 32 Friction generating part 33 Ring member 35 Accommodating member 35a Body part 35b Operation receiving part 37 Threaded member 37a Threaded part 37b Insertion part 37c Flange part 40 Inner tube part 40a Base end part 40b Tip end part 41 Small-diameter part 42 Large-diameter part 43 Tip chip 46 Endoscope visual marker 46a Adhesive 48 Stent holding part 50 Inner shaft 52 Step 54 Protruding and retracting part 55 Marker 56 First marker 57 Second marker 58 Third marker 60 Shaft handle 100 Stent delivery device 200 Stent 300 Guide wire 400 Endoscope

Claims

1. an outer tube part, an outer tube handle to which a proximal end portion of the outer tube part is fixed, an inner tube part slidably inserted axially with respect to the outer tube part, an inner shaft integrated with the inner tube part and extending from the outer tube handle toward the proximal end side, a shaft handle to which a proximal end portion of the inner shaft is fixed, comprising: By retracting the outer tube handle together with the outer tube part toward the shaft handle side, a distal end portion of the inner tube part is exposed from the outer tube part, and a stent held by the inner tube part can be placed in a body cavity. further comprising a fixing ring member provided on an outer periphery of the proximal end portion of the outer tube part, the outer tube handle is a hollow member, a housing recess defined by four wall portions standing from the inner surface is formed on the inner surface of the outer tube handle, in the axial direction, the outer tube part is fixed to the outer tube handle by the fixing ring member being housed in the housing recess, the inner tube part has a stent holding portion into which the stent is externally inserted, the stent holding portion restricts the stent from being displaced axially relative to the inner tube part as the outer tube part retracts or advances, the inner shaft has an emerging and disappearing portion which is a section in which the inner shaft is inserted into the outer tube handle or is exposed on the proximal end side of the outer tube handle according to the retraction amount of the outer tube handle, the emerging and disappearing portion has a plurality of markers respectively formed at a plurality of positions different from each other in the axial direction of the emerging and disappearing portion, the plurality of markers includes a first marker, a stent delivery device in which the stent holding portion is housed inside the outer tube part in a state where the proximal end portion of the outer tube handle is on the distal end side of the first marker.

2. the plurality of markers includes a second marker located on the proximal end side of the first marker, the stent delivery device according to claim 1, wherein the stent holding portion is exposed from the outer tube part in a state where the proximal end portion of the outer tube handle is on the proximal end side of the second marker.

3. due to the thickness of the marker, a step is formed on the outer peripheral surface of the inner shaft at the location where the marker is formed. The stent delivery device according to claim 1 or 2, wherein the outer tube handle has a friction generating portion that generates different frictional resistances when the formation position of the marker on the inner shaft passes therethrough and when the non-formation position of the marker passes therethrough.

4. The stent delivery device according to claim 3, wherein, for at least two markers arranged adjacent to each other among the plurality of markers, the frictional resistances generated by the friction generating portion are different from each other.

5. The outer tube handle includes a switching operation portion capable of switching between a state in which the advancement and retraction of the outer tube handle with respect to the inner shaft are restricted and a state in which the advancement and retraction of the outer tube handle with respect to the inner shaft are possible, The switching operation portion includes a ring member constituted by an elastic body and through which the inner shaft is inserted, a housing member through which the inner shaft is inserted and which houses the ring member, and a screwing member through which the inner shaft is inserted and which is screwed to the housing member, and by screwing the screwing member into the housing member to compress the ring member between the housing member and the screwing member, the advancement and retraction of the switching operation portion with respect to the inner shaft are restricted, The stent delivery device according to claim 3 or 4, wherein the ring member is the friction generating portion.

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