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, a shaft handle 60, and a switching operation part 30. The switching operation part 30 has a ring member 33, a housing member 35, and a screwing member 37. The advancing and retreating of the switching operation part 30 to and from the inner shaft 50 are regulated 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. An outer diameter of the ring member 33 is reduced toward a screwing direction in which the screwing member 37 is screwed into the housing member 35.SELECTED DRAWING: Figure 6

Description

[Technical field]

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

[0002] An example of a stent delivery device used to place a stent in a body cavity is described in Patent Document 1. The stent delivery device in Patent Document 1 (referred to as a placement tool transport device in the document) includes a tubular body that holds a stent (referred to as a placement tool in the document) to be placed in the body cavity, an operation unit that can bend the distal part of the tubular body, and a limiting member that can limit the movement of the stent to the proximal side, and can place the stent in the body cavity by moving the tubular body relative to the limiting member with the distal part of the tubular body bent. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-078459 A Summary of the Invention [Problem to be solved by the invention]

[0004] According to the investigations of the present inventors, the stent delivery device of the cited document 1 still has room for improvement in terms of the structure for realizing the intended placement of the stent.

[0005] The present invention has been made in view of the above problems, and provides a stent delivery device that can easily achieve a stent placement operation more reliably and as intended. [Means for solving the problem]

[0006] According to the present invention, there is provided an outer tube portion, an outer tube handle to which a proximal end of the outer tube portion is fixed; an inner pipe portion that is axially slidably inserted into the outer pipe portion; an inner shaft integral with the inner tubular portion and extending proximally from the outer tubular handle; a shaft handle to which a proximal end of the inner shaft is fixed; Equipped with By retracting the outer tube handle together with the outer tube portion toward the shaft handle, a distal end 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 a body cavity. The outer tube handle is A switching operation unit is provided that can switch between a state in which the outer tube handle is restricted from advancing and retracting relative to the inner shaft and a state in which the outer tube handle is movable relative to the inner shaft, The switching operation unit is a ring member made of an elastic body and having the inner shaft inserted therethrough; a housing member through which the inner shaft is inserted and which houses the ring member; a screw member through which the inner shaft is inserted and which is screwed into the housing member; having The screw member is screwed into the housing member to compress the ring member between the housing member and the screw member, thereby restricting the advancement and retreat of the switching operation part relative to the inner shaft, The outer diameter of the ring member is reduced in a screw-in direction of the screw member into the housing member. And, the housing member includes a housing area that houses the ring member, An end portion of the inner circumferential surface of the storage area in the screw direction has a diameter reduced toward the screw direction, The taper angle of the end of the inner circumferential surface of the storage area is steeper than the taper angle of the outer circumferential surface of the ring member. A stent delivery device is provided. Effect of the Invention

[0007] According to the present invention, it is possible to easily achieve the intended placement operation of the stent. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic overall view of a stent delivery device according to an embodiment. [Diagram 2] FIG. 2 is a cross-sectional view taken along the line AA shown in FIG. [Diagram 3] FIG. 2 is a cross-sectional view taken along line BB shown in FIG. [Figure 4] FIG. 3 is a cross-sectional view taken along the line AA shown in FIG. [Diagram 5] FIG. 2 is a side view showing the internal structure of an outer tube handle according to an embodiment. [Figure 6] FIG. 6(a) is a cross-sectional view taken along the axis of the switching operation unit according to the embodiment, and FIG. 6(b) is a partially enlarged view of part A shown in FIG. 6(a). [Figure 7] FIG. 7(a) is a side view of a ring member in the embodiment, and FIG. 7(b) is a front view showing a screw member in the embodiment. [Figure 8] FIG. 2 is a schematic diagram showing a state in which a stent delivery device according to an embodiment is inserted into an endoscope. [Figure 9] Figures 9(a), 9(b) and 9(c) are figures for explaining the operation of a stent delivery device according to an embodiment, in which Figure 9(a) shows a state in which the tip of the inner tube portion is slightly exposed from the outer tube portion, Figure 9(b) shows a state in which the tip of the inner tube portion is further exposed from the outer tube portion than in the state shown in Figure 9(a), and Figure 9(c) shows a state in which the entire section of the stent placement in the inner tube portion is exposed from the outer tube portion. [Figure 10] Figures 10(a), 10(b) and 10(c) are figures for explaining the operation of the stent delivery device of the embodiment, where Figure 10(a) shows the position of the outer tube handle in a state corresponding to Figure 9(a), Figure 10(b) shows the position of the outer tube handle in a state corresponding to Figure 9(b), and Figure 10(c) shows the position of the outer tube handle in a state corresponding to Figure 9(c). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, an embodiment of the present invention will be described with reference to Fig. 1 to Fig. 10(c). In all drawings, similar components are given the same reference numerals, and descriptions thereof will be omitted as appropriate. In Fig. 1, Fig. 2, Fig. 3, Fig. 4, and Fig. 9(a), a stent 200 is indicated by a two-dot chain line. In Fig. 6(b), the inner shaft 50 and the ring member 33 are omitted. It is not necessary that the various components of the stent delivery device 100 of the present invention are independent of each other. It is acceptable that multiple components are formed as one member, that one component is formed from multiple members, that one component is a part of another component, or that part of one component overlaps with part of another component. In the following description, the distal side of the stent delivery device 100 is also referred to as the tip side, and the proximal side is also referred to as the base side. The tip portion refers to a certain range including the distal end (the most distal end) and its periphery, and the base portion refers to a certain range including the proximal end (the most proximal end) and its periphery.

[0010] As shown in Figure 1, the stent delivery device 100 of this embodiment comprises an outer tube portion 10, an outer tube handle 20 to which the base end 10a of the outer tube portion 10 is fixed, an inner tube portion 40 that is inserted axially slidably through the outer tube portion 10, an inner shaft 50 that is integrated with the inner tube portion 40 and extends from the outer tube handle 20 toward the base end, and a shaft handle 60 to which the base end 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, 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 a body cavity. The outer tube handle 20 includes a switching operation unit 30 that can switch between a state in which the outer tube handle 20 is restricted from advancing and retracting relative to the inner shaft 50 and a state in which the outer tube handle 20 can be advanced and retracted relative to the inner shaft 50. The switching operation unit 30 (see Figures 5 and 6(a)) has a ring member 33 (see Figure 7(a)) made of an elastic body and through which the inner shaft 50 is inserted, a accommodating member 35 through which the inner shaft 50 is inserted and which accommodates the ring member 33, and a screw-fitting member 37 through which the inner shaft 50 is inserted and which is screwed into the accommodating member 35. By screwing the screw member 37 into the accommodating member 35 and compressing the ring member 33 between the accommodating member 35 and the screw member 37, the movement of the switching operating part 30 back and forth relative to the inner shaft 50 is regulated, and the outer diameter of the ring member 33 is reduced in the screwing direction in which the screw member 37 is screwed into the accommodating member 35.

[0011] According to this embodiment, the outer tube handle 20 includes a switching operation unit 30 that can switch between a state in which the outer tube handle 20 is restricted from moving forward and backward relative to the inner shaft 50, and a state in which the outer tube handle 20 can be moved forward and backward relative to the inner shaft 50. This allows the advancement and retreat of the outer tube handle 20 relative to the inner shaft 50 to be appropriately regulated, thereby preventing the outer tube handle 20 from being moved unintentionally and making it easier to retract the outer tube handle 20 toward the shaft handle 60 at the desired timing and by the desired amount. Furthermore, according to this embodiment, the outer diameter of the ring member 33 decreases in the screw-in direction in which the screw member 37 is screwed into the housing member 35. As a result, when the screwing member 37 is screwed into the housing member 35, the ring member 33 is pushed further in the screwing direction inside the housing member 35, so that the screwing member 37 can be sufficiently screwed into the housing member 35. Therefore, the ring member 33 can be sufficiently compressed between the housing member 35 and the screwing member 37, so that the advancement and retreat of the outer tube handle 20 relative to the inner shaft 50 can be more reliably restricted. Therefore, it becomes possible to easily realize the placement operation of the stent as intended.

[0012] In a state where the stent 200 is held by the inner tube portion 40, the stent 200 is accommodated in a contracted state between the inner peripheral surface of the outer tube portion 10 and the outer peripheral surface of the inner tube portion 40. Then, in a state where the outer tube portion 10 and the inner tube portion 40 are inserted into a desired portion of a body cavity along the guide wire 300 (see FIG. 10(a) and the like), the outer tube handle 20 together with the outer tube portion 10 is retracted toward the shaft handle 60 side, and the tip portion 40b of the inner tube portion 40 is exposed from the outer tube portion 10, whereby the stent 200 can be transformed from the contracted state to an expanded state and placed at the desired portion. More specifically, as the tip 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 is in an expanded state. That is, the expansion of the stent 200 progresses according to the amount of retraction of the outer tube handle 20. The contracted state of the stent 200 refers to a state in which the stent 200 is compressed in the radial direction, and the deployed state of the stent 200 refers to 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 Figures 2 and 3, the inner tube portion 40 is inserted into the inner cavity of the outer tube portion 10, and the outer tube portion 10 is slidable relative to the inner tube portion 40 in the axial direction. In this embodiment, the inner and outer diameters of the outer tube portion 10 are constant regardless of the axial position, and therefore the wall thickness of the outer tube portion 10 is constant regardless of the axial position. However, the outer and inner diameters of the outer tube portion 10 may vary depending on the axial position. As shown in Figures 2 and 4, the outer tube portion 10 has a two-layer structure, for example, including an inner layer 14 and an outer layer 15 disposed around the inner layer 14, and is configured by laminating the inner layer 14 and the outer layer 15 in this order from the axial center side of the outer tube portion 10. 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, but examples thereof include hydrophilic resin materials such as maleic anhydride polymers such as polyvinyl alcohol (PVA) and copolymers thereof, and polyvinylpyrrolidone. This can reduce the sliding resistance when the outer tube portion 10 is inserted into the body cavity of the living body.

[0014] The inner layer 14 is the innermost layer of the outer tube portion 10 and is formed, for example, into a cylindrical shape having a constant wall thickness regardless of the position in the axial direction. The inner layer 14 is open at both the distal end and the proximal 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, but may be polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), perfluoroalkoxy fluorine resin (PFA), etc. By making the inner layer 14 of such a fluorine-based polymer material, the sliding resistance when the inner tube portion 40 slides in the lumen 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, the majority (major portion) 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, into a cylindrical shape whose wall thickness is constant regardless of the position in the axial direction. For example, a thermoplastic polymer material can be used for the outer layer 15. Examples of the thermoplastic polymer material include polyimide (PI), polyamideimide (PAI), polyethylene terephthalate (PET), polyethylene (PE), polyamide (PA), polyamide elastomer (PAE), nylon elastomer such as polyether block amide (PEBA), polyurethane (PU), ethylene-vinyl acetate resin (EVA), polyvinyl chloride (PVC), and polypropylene (PP).

[0016] The inner diameter of the outer tube portion 10 is set to a dimension 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. In addition, 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 a reinforcing layer 16 (see Figs. 2 and 3) formed in a mesh shape from braided metal wires, for example. Note that the reinforcing layer 16 is not shown in Fig. 1 and Figs. 8 to 10(c). 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 disposed, for example, from the tip end to the base end of the outer tubular portion 10. The outer tubular portion 10 is reinforced as a whole by the reinforcing layer 16. The reinforcing layer 16 may be formed of, for example, a metal wire wound in a coil shape. The reinforcing layer 16 may be disposed in, for example, a portion of the outer tube portion 10 in the axial direction.

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

[0019] 5, the outer tube handle 20 is, for example, a hollow member, and is formed, for example, in a substantially rectangular parallelepiped shape that is long in one direction. The inner shaft 50 is inserted inside the outer tube handle 20 so as to be slidable relative to the outer tube handle 20, and by moving the outer tube handle 20 along the inner shaft 50 toward the shaft handle 60, the base end 10a of the outer tube section 10 can also be retracted along the inner shaft 50 toward the shaft handle 60. In addition, in describing the outer tube handle 20, the left side in Fig. 5 is referred to as the distal side, and the right side in Fig. 5 is referred to as the proximal side. Also, the direction toward the distal side and proximal side is referred to as the distal-proximal direction. 1 and 5, the outer tube handle 20 has, for example, a first member 22a and a second member 22b, and the first member 22a and the second member 22b are assembled together to form the outer tube handle 20. Note that in Fig. 5, the second member 22b is omitted from illustration, and these figures are side views in which 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. The base end of the outer tube portion 10 is introduced into the inside of the outer tube handle 20 , and the base end portion 10 a of the outer tube portion 10 is arranged along the longitudinal direction of the outer tube handle 20 .

[0020] 5, in 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 an accommodating recess 23, and the fixing ring member 19 is accommodated in the accommodating recess 23, thereby fixing the outer tube portion 10 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 fitted onto the outer tube portion 10. 5, four walls extending from the inner surface of the first member 22a form a rectangular accommodating recess 23 in a side view. The fixing ring member 19 is accommodated inside the accommodating recess 23, and the accommodating recess 23 restricts the movement of the fixing ring member 19 in the tip-proximal direction. Here, two notch-shaped portions 24c are formed in the accommodating recess 23. The shape of each notch-shaped portion 24c when viewed in the proximal-proximal direction is semicircular, and the diameter thereof is set to a dimension slightly larger than the outer diameter of the outer tube portion 10. In the outer tube portion 10, the portion on the proximal side and the portion on the distal side of the fixing ring member 19 protrude outside the accommodating recess 23 via each notch-shaped portion 24c. For example, the accommodating recess 23 may be formed on the inner surface of the second member 22b as well. In this case, a portion of the fixing ring member 19 is disposed inside the accommodating recess 23 of the first member 22a, and the remaining portion of the fixing ring member 19 is disposed inside the accommodating 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, but examples thereof 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 thin diameter portion 41 having a relatively small diameter and a thick diameter portion 42 having a relatively large diameter. Each of the thin diameter portion 41 and the thick diameter portion 42 is a long hollow tubular member. The outer diameter of the thin diameter portion 41 is set to a dimension smaller than the inner diameter of the thick diameter portion 42, and as shown in Fig. 3, a part of the thin diameter portion 41 in the axial direction is inserted into the inner cavity of the thick diameter portion 42. The entire length of the thin diameter portion 41 is set to a dimension longer than the entire length of the thick diameter portion 42. With the thick diameter portion 42 as a reference, the thin diameter portion 41 protrudes from the opening on the tip side of the thick diameter portion 42 toward the tip end and protrudes from the opening on the base end side of the thick diameter portion 42 toward the base end. Here, in the thin diameter section 41, a portion on the distal side of the distal end of the thick diameter section 42 constitutes an arrangement section 41a in which the stent 200 is arranged. The stent 200 is held by the thin diameter section 41 of the inner tube section 40 in a state in which it is inserted into the arrangement section 41a in the thin diameter section 41. Furthermore, a portion of the small diameter portion 41 that is closer to the base end than the base end of the large diameter portion 42 is inserted into the inner cavity of the inner shaft 50. More specifically, the tip end of the inner shaft 50 is inserted into the opening on the base end side of the large diameter portion 42, and the inner cavities of the large diameter portion 42 and the inner shaft 50 communicate with each other. The small diameter portion 41 is inserted through both the inner cavities of the large diameter portion 42 and the inner shaft 50, and further reaches the inside of the shaft handle 60.

[0023] More specifically, for example, an endoscope visible marker 46 is provided at the tip of the large diameter section 42. Thus, in the small diameter section 41, a portion on the tip side of the endoscope visible marker 46 is the arrangement section 41a, and the entire stent 200 is extrapolated to the arrangement section 41a. That is, the endoscope visible marker 46 is arranged on the base end side of the stent 200. Thus, the user can easily grasp the position of the stent 200 based on the image captured by the endoscope, using the position of the endoscope visible marker 46 as an index. More specifically, when the stent delivery device 100 is used, as shown in FIG. 8, at least the portion of the inner tube portion 40 that is distal to the endoscopic visual marker 46 is exposed from the tip of the insertion portion of the endoscope 400. Further, the tip of the endoscope visual marker 46 is fixed to the thin diameter portion 41. More specifically, adhesive 42a is applied in a circumferential manner to the tip of the endoscope visual marker 46 and to a portion of the outer circumferential surface of the thin diameter portion 41 that corresponds to the tip. This fixes the thin diameter portion 41 to the endoscope visual marker 46 and, ultimately, to the thick diameter portion 42. The base end of the endoscope visible marker 46 is connected to the tip side of the large diameter portion 42, and the inner cavity of the endoscope visible marker 46 and the inner cavity of the large diameter portion 42 are connected to each other. Therefore, the small diameter portion 41 is inserted through both the inner cavity of the endoscope visible marker 46 and the inner cavity of the large diameter portion 42. The outer diameter of the endoscope visible marker 46 is set to a dimension approximately equal to the outer diameter of the large diameter portion 42. The endoscope visual marker 46 is, for example, made of a resin tube that is a separate member from the large diameter portion 42, and is colored a different color from the large diameter portion 42. The outer tube portion 10 is also made of, for example, a transparent resin material (transparent to visible light). Therefore, the user can visually recognize the endoscope visual marker 46 through the outer tube portion 10. The endoscope visualization marker 46 may be formed, for example, by applying ink to the tip of the thick-diameter portion 42, or may be made of an X-ray impermeable material such as platinum or tungsten.

[0024] A distal tip 43 (see Figs. 1 and 4) is provided at the distal end of the small diameter section 41. The distal tip 43 is formed, for example, in a cone shape with a diameter gradually decreasing toward the distal end. The base end of the distal tip 43 is connected to the distal end of the small diameter section 41, and the inner cavity of the distal tip 43 and the inner cavity of the small diameter section 41 communicate with each other. When inserting the stent delivery device 100 into a body cavity, the guidewire 300 (see FIG. 9(a) etc.), which has already been inserted into the body cavity, is inserted into the lumen of the inner tubular portion 40 from the opening on the distal end side of the distal tip 43. This allows the outer tubular portion 10 and the inner tubular portion 40 to be inserted into the body cavity along the guidewire 300. Note that in FIGS. 9(a) to 10(c), the guidewire 300 is indicated by a dashed line. In this embodiment, the base end of the distal tip 43 and the distal end of the outer tubular portion 10 face each other. As shown in Fig. 4, the outer diameter of the distal tip 43 is set to a dimension that is substantially equal to or slightly larger than the outer diameter of the outer tubular portion 10, and the inner diameter of the distal tip 43 is set to a dimension that is smaller than the inner diameter of the outer tubular portion 10. Therefore, for example, when the outer tube handle 20 is advanced toward the distal tip 43 together with the outer tube section 10, the distal end surface of the outer tube section 10 abuts against the proximal end surface of the distal tip 43, restricting further advancement of the outer tube section 10 and therefore restricting further advancement of the outer tube handle 20 which is integral with the outer tube section 10. In the following description, the state in which the distal end surface of the outer tube section 10 abuts against the proximal end surface of the distal tip 43 (see FIG. 1, etc.) is defined as the initial state of the stent delivery device 100.

[0025] Furthermore, in this embodiment, a stent holding portion 48 (see FIG. 1, etc.) is provided on the outer periphery of the thin diameter portion 41. The stent holding portion 48 is formed to have a larger diameter than the thin diameter portion 41. The stent holding portion 48 holds the stent 200 in the placement section 41a, and the stent holding portion 48 prevents the stent 200 from being displaced relative to the placement section 41a as the outer tube portion 10 moves back or forward. More specifically, the stent holding portion 48 is, for example, a resin tube, and is fitted onto the outside of the thin-diameter portion 41. In addition, for example, an adhesive (not shown) is applied to the outer circumferential surface of the stent holding portion 48 and near the placement area of ​​the stent holding portion 48 in the placement section 41a, and the stent holding portion 48 is fixed to the placement section 41a by the adhesive. The inner diameter of the stent holding portion 48 is set to be approximately equal to the outer diameter of the thin-diameter portion 41, and the outer diameter of the stent holding portion 48 is set to a dimension smaller than the inner diameter of the outer tube portion 10 and larger than the inner diameter of the stent 200 in a reduced diameter state. The stent 200 is held between the inner circumferential surface of the outer tube portion 10 and the outer circumferential surface of the thin-diameter portion 41 with a portion of the stent 200 in the longitudinal direction being inserted into the stent holding portion 48. More specifically, the portion of the stent 200 inserted into the stent holding portion 48 is sandwiched between the inner circumferential surface of the outer tube portion 10 and the outer circumferential surface of the stent holding portion 48, thereby restricting the stent 200 from being displaced in the axial direction relative to the placement 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 thin-diameter portion 41 is made of, for example, a fluorine-based thermoplastic polymer resin. The fluorine-based thermoplastic polymer material is not particularly limited, but may be polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), perfluoroalkoxy fluororesin (PFA), or the like. By making the thin-diameter portion 41 out of such a fluorine-based polymer material, the sliding resistance when the guidewire 300 slides through the lumen of the thin-diameter portion 41 is reduced. The large diameter portion 42 is integrally molded as a whole from, for example, a thermoplastic polymer material. Examples of the thermoplastic polymer material include polyimide (PI), polyamideimide (PAI), polyethylene terephthalate (PET), polyethylene (PE), polyamide (PA), polyamide elastomer (PAE), nylon elastomer such as polyether block amide (PEBA), polyurethane (PU), ethylene-vinyl acetate resin (EVA), polyvinyl chloride (PVC), and polypropylene (PP). 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 thin-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 thin-diameter portion 41 is not particularly limited, but is preferably 0.05 mm or more and 1 mm or less. In addition, the total length of the thin-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. In addition, 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 tip end of the inner shaft 50 is press-fitted and fixed into the base end of the large diameter portion 42, thereby fixing the large diameter portion 42 and the inner shaft 50 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 present embodiment, the section of the inner shaft 50 that is exposed on the base end side beyond the outer tube handle 20 in the initial state constitutes the recessed portion 54 . The shaft handle 60 is formed, for example, in a cylindrical shape, and is connected to the base end side of the large diameter portion 42, and has an inner cavity that is continuous with the inner cavity of the large diameter portion 42. When using the stent delivery device 100, for example, saline, a contrast agent, or the like can be injected into the inner cavity of the small diameter portion 41 through an opening on the base end side of the shaft handle 60.

[0029] The inner shaft 50 is made of a metal material such as stainless steel (SUS), and the shaft handle 60 is made of 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. Furthermore, 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] As described above, the switching operation unit 30 has a ring member 33 made of an elastic material and through which the inner shaft 50 is inserted, a accommodating member 35 through which the inner shaft 50 is inserted and which accommodates the ring member 33, and a screw-fitting member 37 through which the inner shaft 50 is inserted and which is screwed into the accommodating member 35.

[0032] The ring member 33 is formed, for example, in a substantially 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 its natural state is set to a dimension substantially equal to the outer diameter of the inner shaft 50, for example. The elastic body constituting the ring member 33 is not particularly limited, but examples thereof include elastic materials such as silicone rubber and elastomer.

[0033] In this embodiment, an end portion 33a of the ring member 33 in the screw-in direction is formed into a chamfered shape that reduces in diameter in that direction. As a result, when the screw member 37 is screwed into the housing member 35, the end portion 33a of the ring member 33 is pushed into the housing member 35 satisfactorily. More specifically, the outer diameter of the end 33a in the natural state is tapered so as to gradually decrease in the screwing direction, and the inner diameter of the entire ring member 33 including the end 33a is substantially constant regardless of the position in the screwing direction. The end 33b in the opposite direction to the screw-threading direction is also chamfered so that the diameter of the end 33b tapers in that direction. That is, the outer diameter of the end 33b in its natural state is tapered so that the diameter of the end 33b tapers in the opposite direction to the screw-threading direction. Furthermore, in the ring member 33, the outer diameter of a middle portion 33c (middle portion in the screwing direction) between the end portions 33a and 33b of the ring member 33 is, for example, approximately constant regardless of the position in the screwing direction.

[0034] The housing member 35 is formed in a cylindrical shape with the screw advance direction as the axial direction. The inner shaft 50 is inserted into the inner cavity of the housing member 35 and is slidable relative to the housing member 35 in the axial direction of the housing member 35. More specifically, as shown in FIG. 6(a), the housing member 35 includes, for example, a main body portion 35a into which the screw member 37 is screwed, and an operation receiving portion 35b that receives a switching operation. Each of the main body 35a and the operation receiving portion 35b is formed in a cylindrical shape with the screw advance direction as the axial direction. The base end side of the main body 35a is connected to the tip side of the operation receiving portion 35b. The main body 35a and the operation receiving portion 35b are arranged coaxially with each other, and the inner cavity of the main body 35a and the inner cavity of the operation receiving portion 35b are connected to each other. The inner diameter of the main body 35a is larger than the inner diameter (maximum diameter) of the operation receiving portion 35b, and the outer diameter of the main body 35a is smaller than the outer diameter of the operation receiving portion 35b. Also, as shown in FIG. 5, the outer peripheral surface of the operation receiving portion 35b has, for example, a plurality of grooves extending in the axial direction thereof, intermittently arranged in the circumferential direction of the operation receiving portion 35b, and the plurality of grooves and the portions between adjacent grooves form a plurality of projections and recesses arranged alternately in the circumferential direction.

[0035] Here, the accommodation member 35 includes an accommodation region 36 that accommodates the ring member 33, and an end portion 36a of the inner circumferential surface of the accommodation region 36 in the screwing direction has a diameter that is reduced in the screwing direction. As a result, when the screw member 37 is screwed into the housing member 35, the ring member 33 is compressed in the radial direction as the screw member 37 advances. Therefore, the inner shaft 50 can be sufficiently fastened by the ring member 33, so that the advancement and retreat of the outer tube handle 20 relative to the inner shaft 50 can be more reliably regulated. More specifically, in the inner cavity of the operation receiving portion 35b, the tip side portion constitutes the accommodation area 36, ​​and the portion on the base end side of the accommodation area 36 is formed to have a smaller diameter than the outer diameter of the ring member 33, and serves as a non-accommodation area.

[0036] The threaded member 37 is formed in a cylindrical shape with the screw advance direction as the axial direction. The inner shaft 50 is inserted into the inner cavity of the threaded member 37 and is slidable relative to the threaded member 37 in the axial direction of the threaded member 37. More specifically, as shown in Figures 6(a) and 6(b), the screwing member 37 includes, for example, a screwing portion 37a that screws into the accommodating member 35, a flange portion 37c formed on the tip side of the screwing portion 37a, and an insertion portion 37b that is inserted into the inner cavity of the main body portion 35a of the accommodating member 35. The screw thread portion 37a and the insertion portion 37b are each formed, for example, in a cylindrical shape with the tip-base direction as the axial direction, and are arranged coaxially with each other. The base end of the screw thread portion 37a is connected to the tip of the insertion portion 37b. The inner cavity of the screw thread portion 37a and the inner cavity of the insertion portion 37b are connected to each other. The outer diameter of the screw thread 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 screw thread portion 37a is set to a dimension approximately equal to the inner diameter of the insertion portion 37b, for example. As shown in FIG. 7(b), the outer shape of flange portion 37c when viewed in the axial direction is, for example, a regular hexagon, and the outer peripheral surface of flange portion 37c is composed of six faces, and the six faces are formed in planes that are perpendicular to the axial direction. The radial dimension of the flange portion 37c is greater than the outer diameter of the screw portion 37a.

[0037] In this embodiment, the screw member 37 is screwed into the housing member 35 from the tip side. More specifically, a screw thread is formed on the outer peripheral surface of the screw portion 37a, and the screw portion 37a is a male screw portion. A screw thread is formed on the inner peripheral surface of the main body portion 35a, and the main body portion 35a is a female screw portion. The female screw portion and the male screw portion are screwed together, thereby connecting the screw member 37 and the housing member 35 to each other. The ring member 33 is disposed between the end face on the base end side of the screw portion 37a and the end portion 39a of the inner peripheral surface of the housing area 36. The inner shaft 50 is inserted through the inner cavity of the screw member 37 and the inner cavity of the housing member 35. The inner shaft 50 protrudes from the opening on the tip side of the screw member 37 to the tip side, and protrudes from the opening on the base side of the housing member 35 to the base side.

[0038] Each of the housing member 35 and the screw member 37 is made of, for example, a hard resin material. This resin material is not particularly limited, but examples thereof include polyolefins such as polyethylene and polypropylene, polyamide, polycarbonate, polystyrene, etc. The housing member 35 and the screw member 37 may be made of the same type of resin material, or may be made of different resin materials.

[0039] Here, inside the outer tube handle 20, a pair of holding portions 25 for holding the screw-fitting member 37 and an accommodating portion 26 for accommodating the accommodating member 35 are formed. The pair of holding portions 25 restrict rotation of the screw member 37 relative to the outer tube handle 20, while the accommodating portion 26 allows rotation of the accommodating member 35 relative 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 accommodating portion 26. In the present embodiment, by rotating the accommodating member 35 out of the screw member 37 and the accommodating member 35, the screw member 37 moves in the screw advance direction.

[0040] More specifically, each of the pair of holding portions 25 is configured by a pair of flat 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 sandwiched therebetween. More specifically, one of six faces constituting the outer circumferential surface of the flange portion 37c is in surface contact with one of the pair of wall portions, and a face parallel to the face is in surface contact with the other of the pair of wall portions. Therefore, while movement of the screw member 37 in the tip-proximal direction is permitted, the screw member 37 is held by the pair of holding portions 25 in a state in which rotation of the screw member 37 is restricted. However, in the case of this embodiment, a restricting plate 27 that restricts the screw member 37 from moving further toward the tip side than the holding portion 25 is formed on the inner surface of the first member 22a between the pair of holding portions 25. This restricts the screw member 37 from moving further toward the base end than the restricting plate 27. The shape of flange portion 37c when viewed in the proximal-tip direction is not particularly limited as long as the outer circumferential surface has a pair of surfaces opposed to each other. Furthermore, such a pair of holding portions 25 may also be formed, for example, on the inner surface of the second member at positions corresponding to the holding portions 25 of the first member 22a.

[0041] In this embodiment, four walls are erected on the inner surface of the first member 22a. The four walls are assembled to form a frame-like storage section 26 that is generally rectangular in side view. Two notch-shaped sections 26a are formed in the storage section 26, one of which allows the main body section 35a to pass through to the tip side, and the other of which allows the inner shaft 50 to pass through to the base end side. This allows the storage member 35 to rotate around its axis relative to the outer tube handle 20 while being stored inside the storage section 26. The user can then perform a switching operation by, for example, rotating the operation receiving section 35b around its axis. Incidentally, such a storage portion 26 may also be formed, for example, on the inner surface of the second member 22b at a portion corresponding to the storage portion 26 of the first member 22a. Here, in each of the first member 22a and the second member 22b, an opening 22c (see FIG. 1) that connects the internal space of the outer tube handle 20 to the outside of the outer tube handle 20 is formed in a portion corresponding to the operation receiving portion 35b. At least a portion of the operation receiving portion 35b in the circumferential direction is accessible by the user's fingers from the outside of the outer tube handle 20 through the opening 22c. Note that the portion 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 generally rectangular shape in side view.

[0042] In this embodiment, the screwing direction in which the screw member 37 is screwed into the housing member 35 is the proximal direction. More specifically, the outer tube handle 20 can be switched to a state in which the advancement and retreat of the outer tube handle 20 relative to the inner shaft 50 is restricted by an operation of rotating the operation receiving portion 35b of the housing member 35 in one circumferential direction relative to the outer tube handle 20 (hereinafter, a closing operation). With the closing operation, the screw member 37 screws into the housing member 35 and advances from the tip side to the base end side. At this time, with the screwing of the screw member 37, the end portion 39a of the inner circumferential surface of the housing region 36 and the end face of the base end side of the screwing portion 37a of the screwing member 37 approach each other in the screwing direction. As a result, the ring member 33 arranged between the end portion 39a of the inner circumferential surface of the housing region 36 and the end face of the base end side of the screwing portion 37a are pressed against each other by the faces and elastically deformed, becoming 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 in which it is circumferentially fastened by the ring member 33 compressed in the proximal-proximal direction. Furthermore, by rotating the operation receiving portion 35b of the housing member 35 in the other circumferential direction (the opposite direction to the rotation direction in the closing operation) relative to the screw member 37 (hereinafter, the opening operation), the housing member 35 can be switched to a state in which the outer tube handle 20 can be advanced and retreated relative to the inner shaft 50. With the opening operation, the screw member 37 moves toward the tip side, the ring member 33 is released from the compressed state, and the switching operation portion 30 can be advanced and retreated relative to the inner shaft 50. Here, as described above, the restricting plate 27 is disposed between the pair of holding parts 25 that hold the screwing member 37. When the screwing member 37 comes into contact with the restricting plate 27, the screwing between the accommodating member 35 and the screwing member 37 is restricted from being completely released. The screwing direction of the screw member 37 is not limited to from the distal end to the proximal end, and the screw member 37 may be configured to screw from the proximal end to the distal end. In this case, the positional relationship between the housing member 35 and the screw member 37 is reversed in the tip-proximal end direction.

[0043] Here, the end 36a of the accommodation region 36 includes, for example, a first region 36b and a second region 36c adjacent to the first region 36b on the side in the screw advancement direction. The taper angle (R1 shown in FIG. 6(b)) of the inner circumferential surface 39b of the first region 36b and the taper angle (R2 shown in FIG. 6(b)) of the inner circumferential surface 39c of the second region 36c are different from each other. In this embodiment, the taper angle R2 of the inner circumferential surface 39c of the second region 36c is gentler than the taper angle R1 of the inner circumferential surface 39b of the first region 36b. In other words, the taper angle R1 of the inner circumferential surface 39b of the first region 36b is steeper than the taper angle R2 of the inner circumferential surface 39c of the second region 36c. As a result, when the screw member 37 is screwed into the housing member 35, a sufficient resistance (resistance toward the tip side) against the ring member 33 can be obtained from the first region 36b. In addition, since a sufficient frictional resistance is generated between the inner peripheral surface 39c of the second region 36c and the outer peripheral surface of the ring member 33, the ring member 33 can be well held by the second region 36c. Therefore, the ring member 33 arranged between the end portion 39a of the inner peripheral surface of the housing region 36 and the end face on the base end side of the screw portion 37a can be sufficiently pressed by the surfaces. Therefore, the ring member 33 can be well compressed, so that the advancement and retreat of the outer tube handle 20 relative to the inner shaft 50 can be more reliably regulated. Here, "loose" means that the inclination angle is closer to the extension direction of the axis center AX of the housing member 35 shown in FIG. 6(b). More specifically, each of the first region 36b and the second region 36c is tapered in the screw advance direction. The inner diameter of the base end of the first region 36b is set to, for example, a dimension equivalent to the inner diameter of the tip end of the second region 36c. In addition, the taper angle R1 of the inner peripheral surface 39b of the first region 36b is preferably, for example, greater than 45 degrees, and the taper angle R2 of the inner peripheral surface 39c of the second region 36c is preferably, for example, less than 45 degrees. In the present invention, for example, the taper angle R1 of the inner peripheral surface 39b of the first region 36b may be gentler than the taper angle R2 of the inner peripheral surface 39c of the second region 36c. In this case, when the screw member 37 is screwed into the housing member 35, a sufficient resistance (resistance toward the tip side) against the ring member 33 can be obtained from the second region 36c, so that the ring member 33 can be sufficiently pressed by the inner peripheral surface 39c of the second region 36c and the end face on the base end side of the screw portion 37a. Therefore, the ring member 33 can be compressed well, so that the advancement and retreat of the outer tube handle 20 relative to the inner shaft 50 can be more reliably regulated.

[0044] Furthermore, in this embodiment, the taper angle of the end 39a of the inner circumferential surface of the accommodation area 36 is steeper than the taper angle (R3 shown in FIG. 7(a)) of the outer circumferential surface of the ring member 33. As a result, when the screw member 37 is screwed into the housing member 35, a sufficient resistance (resistance toward the tip side) against the ring member 33 can be obtained from the end portion 39a of the inner peripheral surface of the housing area 36. Therefore, the ring member 33 arranged between the end portion 39a of the inner peripheral surface of the housing area 36 and the end face on the base end side of the screw portion 37a can be pressed well by these surfaces, so that the advancement and retreat of the outer tube handle 20 relative to the inner shaft 50 can be more reliably regulated. More specifically, in this embodiment, the taper angle R1 of the inner circumferential surface 39b of the first region 36b is steeper than the taper angle R3 of the outer circumferential surface of the ring member 33. Also, the taper angle R3 of the outer circumferential surface of the ring member 33 is steeper than the taper angle R2 of the inner circumferential surface 39c of the second region 36c.

[0045] An example of a method of using the stent delivery device 100 of this embodiment will now be described. In the following, as an example, a case will be described in which the stent delivery device 100 is used in a procedure for placing a stent 200 inside a bile duct (not shown). The description will be given from the state in which the tip of the insertion portion of endoscope 400 (see FIG. 8) is placed inside the duodenum (not shown) near the duodenal papilla (papilla of Vater), a pinhole is formed in the bile duct (not shown), and the tip of guidewire 300 is anchored (locked) to the pinhole. First, the stent delivery device 100 is introduced along the guidewire 300. More specifically, the small diameter portion 41 of the inner tube portion 40 is inserted onto the guidewire 300, and the inner tube portion 40 and the outer tube portion 10 are fed to the needle hole while sliding the inner tube portion 40 from the base end side to the tip end side along the axial direction of the guidewire. At this time, the switching operation unit 30 is set in a state in which the outer tube handle 20 is restricted from advancing and retracting relative to the inner shaft 50. Next, when the placement section 41a of the stent 200 in the inner tube portion 40 is inserted to the inside of the bile duct, the stent 200 is placed. More specifically, first, the switching operation unit 30 is switched to a state in which the outer tube handle 20 can be advanced and retracted relative to the inner shaft 50. Then, while holding the shaft handle 60 with one hand, the outer tube handle 20 is retracted toward the shaft handle 60 together with the outer tube section 10 with the other hand, thereby exposing the tip section 40b of the inner tube section 40 from the outer tube section 10 (see Figs. 9(a) and 10(a)). Next, the outer tube handle 20 is retracted until the entire arrangement section 41a of the stent 200 in the inner tube section 40 is exposed from the outer tube section 10, whereby the entire stent 200 changes from the contracted state to the deployed state (see Figs. 9(c) and 10(c)). Then, in a state where the outer tube handle 20 is advanced together with the outer tube portion 10 until the distal end of the outer tube portion 10 abuts against the distal tip, the switching operation unit 30 again switches to a state where the advancement and retreat of the outer tube handle 20 relative 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 guidewire 300 is also removed from the body cavity. In this embodiment, when placing the stent 200, in a state where the tip portion 40b of the inner tube portion 40 is exposed from the outer tube portion 10 and the stent holding portion 48 is housed inside the outer tube portion 10 (see Figs. 9(b) and 10(b)), by advancing the outer tube handle 20, the outer tube portion 10 advances relative to the stent 200, and the stent 200 can be re-housed in the outer tube portion 10. As a result, even if the deployment of the stent 200 is unintentionally started at a position other than the desired position in the body cavity, the position of the stent 200 in the body cavity together with the outer tube portion 10 and the inner tube portion 40 can be adjusted by re-housed the stent 200 in the outer tube portion 10.

[0046] The present invention is not limited to the above-described embodiment, and includes various modifications and improvements as long as the object of the present invention is achieved.

[0047] The present embodiment encompasses the following technical ideas. (1) an outer tube portion; an outer tube handle to which a proximal end of the outer tube portion is fixed; an inner pipe portion that is axially slidably inserted into the outer pipe portion; an inner shaft integral with the inner tubular portion and extending proximally from the outer tubular handle; a shaft handle to which a proximal end of the inner shaft is fixed; Equipped with By retracting the outer tube handle together with the outer tube portion toward the shaft handle, a distal end 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 a body cavity. The outer tube handle is A switching operation unit is provided that can switch between a state in which the outer tube handle is restricted from advancing and retracting relative to the inner shaft and a state in which the outer tube handle is movable relative to the inner shaft, The switching operation unit is a ring member made of an elastic body and having the inner shaft inserted therethrough; a housing member through which the inner shaft is inserted and which houses the ring member; a screw member through which the inner shaft is inserted and which is screwed into the housing member; having The screw member is screwed into the housing member to compress the ring member between the housing member and the screw member, thereby restricting the advancement and retreat of the switching operation part relative to the inner shaft, A stent delivery device, wherein the outer diameter of the ring member decreases in a screwing direction in which the screw member is screwed into the housing member. (2) The stent delivery device according to (1), wherein the end of the ring member in the screwing direction is formed into a chamfered shape that reduces in diameter in that direction. (3) The housing member includes a housing area that houses the ring member, The stent delivery device according to claim 1, wherein an end portion of the inner circumferential surface of the storage area in the screw direction is tapered in diameter in the screw direction. (4) A stent delivery device as described in (3), wherein the taper angle of the end of the inner circumferential surface of the storage area is steeper than the taper angle of the outer circumferential surface of the ring member. (5) The end of the storage area includes a first area and a second area adjacent to the first area in the screw direction, The stent delivery device according to (3) or (4), wherein a taper angle of the inner circumferential surface of the first region and a taper angle of the inner circumferential surface of the second region are different from each other. (6) The stent delivery device according to (5), wherein the taper angle of the inner circumferential surface of the second region is gentler than the taper angle of the inner circumferential surface of the first region. (7) A stent delivery device according to any one of (1) to (6), wherein the screw advancement direction is a proximal direction. [Explanation of symbols]

[0048] 10 Outer tube part 10a Proximal end 10b Tip 11 Marker material 14 Inner layer 15 Outer layer 16 Reinforcement layer 19 Fixing ring member 20 Outer tube handle 22a First member 22b Second member 22c opening 23 Recessed portion 24c Notched section 25 Holding part 26 Storage unit 26a Notch shape 27 Regulatory Board 30 Switching operation section 33 Ring member 33a, 33b end 33c middle part 35 Storage material 35a Main body 35b Operation receiver 36 Containment Area 36a end 36b 1st area 36c 2nd area 37 Screw-fitting members 37a Threaded part 37b Insertion part 37c Flange part 39a End (end of the inner periphery of the storage area) 39b, 39c Inner surface 40 Inner pipe section 40a Proximal end 40b Tip 41 Thin section 42 Large diameter part 43 Tip 46 Endoscopic Visible Marker 46a Adhesive 48 Stent holding part 50 Inner shaft 54 Haunting part 60 Shaft Handle 100 Stent delivery device 200 stents 300 Guidewire 400 Endoscope AX axis center

Claims

1. An outer tube portion; an outer tube handle to which a proximal end of the outer tube portion is fixed; an inner pipe portion that is axially slidably inserted into the outer pipe portion; an inner shaft integral with the inner tubular portion and extending proximally from the outer tubular handle; a shaft handle to which a proximal end of the inner shaft is fixed; Equipped with By retracting the outer tube handle together with the outer tube portion toward the shaft handle, a distal end 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 a body cavity. The outer tube handle is A switching operation unit is provided that can switch between a state in which the outer tube handle is restricted from advancing and retracting relative to the inner shaft and a state in which the outer tube handle is movable relative to the inner shaft, The switching operation unit is a ring member made of an elastic body and having the inner shaft inserted therethrough; a housing member through which the inner shaft is inserted and which houses the ring member; a screw member through which the inner shaft is inserted and which is screwed into the housing member; having The screw member is screwed into the housing member to compress the ring member between the housing member and the screw member, thereby restricting the advancement and retreat of the switching operation part relative to the inner shaft, an outer diameter of the ring member decreases in a screw-in direction of the screw member into the housing member, the housing member includes a housing area that houses the ring member, An end portion of the inner circumferential surface of the storage area in the screw direction has a diameter reduced toward the screw direction, A stent delivery device, wherein the taper angle of the end of the inner circumferential surface of the storage area is steeper than the taper angle of the outer circumferential surface of the ring member.

2. An outer tube portion, an outer tube handle to which a proximal end of the outer tube portion is fixed; an inner pipe portion that is axially slidably inserted into the outer pipe portion; an inner shaft integral with the inner tubular portion and extending proximally from the outer tubular handle; a shaft handle to which a proximal end of the inner shaft is fixed; Equipped with By retracting the outer tube handle together with the outer tube portion toward the shaft handle, a distal end 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 a body cavity. The outer tube handle is A switching operation unit is provided that can switch between a state in which the outer tube handle is restricted from advancing and retracting relative to the inner shaft and a state in which the outer tube handle is movable relative to the inner shaft, The switching operation unit is a ring member made of an elastic body and having the inner shaft inserted therethrough; a housing member through which the inner shaft is inserted and which houses the ring member; a screw member through which the inner shaft is inserted and which is screwed into the housing member; having The screw member is screwed into the housing member to compress the ring member between the housing member and the screw member, thereby restricting the advancement and retreat of the switching operation part relative to the inner shaft, an outer diameter of the ring member decreases in a screw-in direction of the screw member into the housing member, the housing member includes a housing area that houses the ring member, An end portion of the inner circumferential surface of the storage area in the screw direction has a diameter reduced toward the screw direction, The end of the storage area includes a first area and a second area adjacent to the first area in the screw direction, A stent delivery device, wherein the taper angle of the inner circumferential surface of the first region and the taper angle of the inner circumferential surface of the second region are different from each other.

3. 3. The stent delivery device according to claim 1, wherein an end portion of the ring member in the screwing direction is formed into a chamfered shape such that the diameter of the end portion decreases in the screwing direction.

4. The stent delivery device according to claim 2 , wherein the taper angle of the inner circumferential surface of the second region is gentler than the taper angle of the inner circumferential surface of the first region.

5. The stent delivery device according to claim 1 , wherein the screw advancement direction is a proximal direction.

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