medical equipment

Abstract

To provide medical equipment with a structure capable of appropriately keeping the shape in a natural state of an indwelling tool.SOLUTION: Medical equipment 100 includes a tubular indwelling tool 10 and an inner catheter 20 inserted into the indwelling tool 10. In the medical equipment 100, the inner catheter 20 is a resin tube. In the inner catheter 20, a region inserted into the indwelling tool 10 includes a plurality of air gaps 25 dotted in the resin, and includes a flexible part 30 easily bent in a direction intersecting with an axial direction of the inner catheter 20.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to medical devices. [Background technology]

[0002] An example of a medical device is described in Patent Document 1. The medical device of Patent Document 1 (referred to in the document as a stent delivery system) has a tubular indwelling device (referred to in the document as a stent) and an inner catheter (referred to in the document as a guide catheter) inserted into the indwelling device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-297502 Summary of the Invention [Problem to be solved by the invention]

[0004] According to the investigations of the present inventors, there is still room for improvement in the technology of Patent Document 1 with regard to the structure that maintains the shape of the indwelling device in its natural state.

[0005] The present invention has been made in view of the above problems, and provides a medical device having a structure that enables an indwelling device to favorably maintain the shape of its natural state. [Means for solving the problem]

[0006] According to the present invention, there is provided a medical device having a tubular indwelling device and an inner catheter inserted into the indwelling device, the inner catheter is a resin tube, In the inner catheter, the region where the indwelling device is inserted is The resin tube Multiple voids scattered throughout the resin a flexible portion including The flexible portion is formed by the plurality of voids scattered in the resin.Easy bending in a direction crossing the axial direction of the inner catheter It has become A medical device is provided. [Effects of the Invention]

[0007] According to the present invention, it is possible to realize a medical device having a structure that allows the indwelling device to maintain the shape of its natural state in a satisfactory manner. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram showing the overall configuration of a medical device according to an embodiment. [Figure 2] FIG. 2 is a side view showing an indwelling device and its surrounding structure in the medical device according to the embodiment. [Figure 3] FIG. 2 is a side view of the indwelling device according to the embodiment. [Figure 4] FIG. 2 is a side view of the inner catheter according to the embodiment, showing the flexible portion and its surrounding structure. [Figure 5] 3 is a cross-sectional view showing a flexible portion and its surrounding structure in the embodiment. FIG. [Figure 6] FIG. 5 is a partial enlarged view of part A shown in FIG. [Figure 7] FIG. 4 is a partially enlarged view of a gap in the embodiment.

[0009] First, an embodiment will be described using Figures 1 to 7. In all drawings, similar components are given the same reference numerals, and descriptions will be omitted where appropriate. Figure 3 shows the shape of the indwelling device 10 in its natural state, and Figure 4 shows the shape of the inner catheter 20 in its natural state. Figure 5 is a cross-sectional view taken along the axial direction of the inner catheter 20. In Figure 7, the vertical direction of the paper is the radial direction of the inner catheter 20, and the horizontal direction of the paper is the axial direction of the inner catheter 20. Furthermore, the various components of the medical device 100 of the present invention do not need to be independent entities, and it is acceptable for one component to be a part of another component, or for part of one component to overlap with part of another component, etc. In the following description, the tip portion 21 refers to a region of a predetermined length in the inner catheter 20 of the medical device 100 that includes the end (distal end) of the inner catheter 20 on the insertion tip side of the inner catheter 20. The base end portion refers to a region of a predetermined length in each part of the inner catheter 20 that includes the end (proximal end) on the base end side of the inner catheter 20. The tip-to-base direction refers to the longitudinal direction of the inner catheter 20. The axis refers to the central axis along the longitudinal direction of the inner catheter 20. In the following description, the axial direction of the inner catheter 20 may be simply referred to as the axial direction, and the radial direction of the inner catheter 20 may be simply referred to as the radial direction. Furthermore, unless otherwise specified, the description of the shape of each part of the medical device 100 is a description of the shape in its natural state when no external force is applied.

[0010] The medical device 100 according to this embodiment includes a tubular indwelling device 10 and an inner catheter 20 inserted through the indwelling device 10. As shown in Figures 6 and 7, the inner catheter 20 is a resin tube, and the area of ​​the inner catheter 20 that is inserted into the indwelling device 10 has multiple voids 25 scattered throughout the resin and a flexible portion 30 that can be easily bent in a direction that intersects the axial direction of the inner catheter 20.

[0011] In this embodiment, when the inner catheter 20 is housed in the indwelling device 10, the portion of the inner catheter 20 that is inserted into the indwelling device 10 has a shape that corresponds to the shape of the indwelling device 10 and is housed in the indwelling device 10. The medical device 100 is used to place the indwelling device 10 at a desired site inside a living body lumen. After the indwelling device 10 and the inner catheter 20 are inserted into a desired site in the living body, the inner catheter 20 is removed from the indwelling device 10, and the indwelling device 10 is placed at the desired site. In this state, the indwelling device 10 has a natural shape (the shape shown in FIG. 3) or a shape close to the natural shape.

[0012] According to this embodiment, the inner catheter 20 has a flexible section 30 in the region inserted into the indwelling device 10, which is easily bent in a direction intersecting the axial direction of the inner catheter 20. This allows the inner catheter 20 to bend while properly following the shape of the indwelling device 10 when the inner catheter 20 is inserted into the indwelling device 10, thereby preventing the indwelling device 10 from deforming into the shape of the inner catheter 20. Therefore, the shape of the indwelling device 10 in its natural state can be properly maintained. More specifically, the flexible portion 30 has a plurality of voids 25, which gives the flexible portion 30 lower bending rigidity than the other portions of the inner catheter 20 other than the flexible portion 30. This makes it easier for the flexible portion 30 to bend in a direction intersecting the axial direction of the inner catheter 20. The bending rigidity referred to here is expressed as the product of the moment of inertia, which is determined by the cross-sectional shape and size of the member, and the Young's modulus of the material.

[0013] In the present embodiment, the indwelling device 10 is a stent, for example. However, the indwelling device 10 may also be a stent graft, for example.

[0014] In the present embodiment, the indwelling device 10 has a bent portion 15 that has been formed into a bent shape in advance, and the flexible portion 30 is inserted into the bent portion 15 . The presence of the bent portion 15 in the indwelling device 10 improves the anchoring ability of the indwelling device 10 to the inner wall of the biological lumen. Furthermore, since the flexible portion 30 is inserted into the bent portion 15, the bent portion 15 can be prevented from being deformed to the shape of the flexible portion 30. Therefore, the anchoring ability of the indwelling device 10 can be maintained well.

[0015] The indwelling device 10 is a long, hollow tubular member. As shown in Figure 3, the indwelling device 10 has a distal end portion 11, a proximal end portion 12, and an intermediate portion 13 located between the distal end portion 11 and the proximal end portion 12. For example, the distal end portion 11 and the proximal end portion 12 each constitute a curved portion 15. However, the present invention is not limited to this example, and either the distal end portion 11 or the proximal end portion 12 of the indwelling device 10 may constitute the curved portion 15. The intermediate portion 13 extends, for example, linearly. The distal end of the intermediate portion 13 is connected to the proximal end of the distal portion 11, and the proximal end of the intermediate portion 13 is connected to the distal end of the proximal end portion 12. The distal end portion 11 and the proximal end portion 12 are formed, for example, in a substantially symmetrical shape relative to each other in the distal-proximal direction with respect to the intermediate portion 13. More specifically, the distal end portion 11 and the proximal end portion 12 are each formed, for example, in a convex arc shape in a direction away from the intermediate portion 13 in the axial direction of the intermediate portion 13. The general angle R1 of the distal end 11 and the general angle R2 of the proximal end 12 are set to be, for example, equal to each other. More specifically, as an example, the central angle (general angle R1) of the distal end 11 and the central angle (general angle R2) of the proximal end 12 are each about 200 degrees. The radius of curvature of the distal end portion 11 and the radius of curvature of the proximal end portion 12 are set to be, for example, equal to each other. That is, the distal end portion 11 and the proximal end portion 12 are formed to have, for example, the same shape. However, the distal end portion 11 and the proximal end portion 12 may be formed in different shapes from each other. That is, the general angle R1 of the distal end portion 11 and the general angle R2 of the proximal end portion 12 may be set to different angles from each other, and the radius of curvature of the distal end portion 11 and the radius of curvature of the proximal end portion 12 may be set to different radii of curvature from each other. Furthermore, the indwelling device 10 may not have the bent portion 15 and may be formed in a substantially straight line as a whole. Furthermore, for example, a plurality of (for example, five) openings 17 are formed on the outer peripheral surface 10b of each of the distal end portion 11 and the proximal end portion 12. The openings 17 are, for example, side holes whose depth direction is perpendicular to the axial direction of the indwelling device 10, and open to the outer peripheral surface 10b of the indwelling device 10.

[0016] 1, 2, and 3, the indwelling device 10 is formed with a marking portion 19 that indicates, for example, the placement area of ​​the base end portion 12. In addition, in Fig. 1, 2, and 3, the area where the marking portion 19 is formed is shaded with dots. By using the position of the marking portion 19 as an index, the position of the base end portion 12 within the lumen of the living body can be accurately recognized, for example, via an image captured by an endoscope. The marking portion 19 is formed by applying ink, for example. The color of the ink is not particularly limited, but one example is black. Furthermore, for example, the marking portion 19 may be made of ink or a ring member made of an X-ray impermeable material such as platinum or tungsten.

[0017] The indwelling device 10 is made of a resin material such as polyurethane, polyethylene, silicone, polyamide, polyamideimide, vinyl chloride, polyethersulfone, etc. In particular, by making the indwelling device 10 of a resin material such as polyurethane, polyethylene, polyamide, polyamideimide, etc., the workability of the indwelling device 10 is improved.

[0018] It is also preferable that, for example, a hydrophilic layer (not shown) is formed on the outer peripheral surface of the indwelling device 10. This can reduce the sliding resistance when the medical device 100 is inserted into a body lumen. The hydrophilic layer may be formed over the entire length of the indwelling device 10, or may be formed in a region on the distal end side of the indwelling device 10 over a partial length thereof. 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.

[0019] The total length of the indwelling device 10 is not particularly limited, but is preferably 30 mm or more and 1000 mm or less, and more preferably 50 mm or more and 500 mm or less. The outer diameter of the indwelling device 10 is not particularly limited, but is preferably 1.5 mm or more and 5 mm or less. The length (dimension in the axial direction) of each of the distal end 11 and proximal end 12 of the indwelling device 10 is not particularly limited, but is preferably 30 mm or more and 100 mm or less. The general angles R1, R2 of the distal end 11 and proximal end 12 of the indwelling device 10 are not particularly limited, but are preferably 150 degrees or more and 540 degrees or less. The radius of curvature of each of the distal end 11 and proximal end 12 of the indwelling device 10 is not particularly limited, but is preferably 5 mm or more and 15 mm or less.

[0020] In the present embodiment, for example, the inner and outer diameters of the indwelling device 10 are substantially constant, and therefore the wall thickness is substantially constant. However, as will be described later, the inner and outer diameters of the most distal end of the indwelling device 10 may each vary in the axial direction. Furthermore, it is preferable that the inner diameter of the indwelling device 10 is larger than the outer diameter of the inner catheter 20. This allows the indwelling device 10 to be easily attached to and detached from the inner catheter 20.

[0021] 4, the inner catheter 20 is a long, hollow tubular member. In addition, the inner catheter 20 (excluding the flexible portion 30) in its natural state is formed, for example, in a substantially linear shape. In this embodiment, the inner catheter 20 is inserted through the indwelling device 10 so as to be removable by sliding it in the axial direction relative to the indwelling device 10. In the initial state, at least the flexible portion 30 of the inner catheter 20 is inserted into the indwelling device 10. In this state, the inner catheter 20 is bent, for example, along the bent shape of the bending portion 15 (the distal end 11 and the proximal end 12). In addition, the distal end 21 and the proximal end 12 of the inner catheter 20 are exposed to the outside from the indwelling device 10, for example. Furthermore, as described above, the flexible portion 30 has a plurality of voids 25 scattered throughout the resin, but the lumen of the inner catheter 20 is liquid-tightly shielded from the outside by the tube wall of the inner catheter 20. This allows, for example, liquids such as saline or medicinal liquids to be injected into the body through the lumen of the inner catheter 20. 6, the inner catheter 20 is made liquid-tight by the portions (resin) of the inner catheter 20 that are not the voids 25. Therefore, the lumen of the inner catheter 20 is configured so that the liquid flowing within the lumen does not leak from the inner catheter 20 to the outside through the voids 25.

[0022] The flexible portion 30 is preferably formed, for example, in the inner catheter 20 at least in the region that will be inserted through the bent portion 15 of the indwelling device 10. More specifically, in the case of this embodiment, the flexible portion 30 is preferably formed, for example, in the inner catheter 20 at least in the region that will be inserted through the distal end 11 of the indwelling device 10 and the region that will be inserted through the proximal end 12 of the indwelling device 10. However, the flexible portion 30 may be formed, for example, over the entire region 36 of the inner catheter 20 that is inserted into the indwelling device 10, or may be formed in only a part of that region 36. In this embodiment, the flexible section 30 is disposed in an intermediate section 35 in the axial direction of the inner catheter 20. The intermediate section 35 here refers to the section between the distal end 21 and the proximal end (not shown) in the axial direction of the inner catheter 20, and the intermediate section 35 includes a region 36 that is inserted into the indwelling device 10 and a region 37 that is a section on the proximal side of the region 36 and is not inserted into the indwelling device 10 (a region that is exposed from the indwelling device 10 when housed in the indwelling device 10). In the intermediate section 35, the distal end of the region 36 that is inserted into the indwelling device 10 is connected, for example, to the proximal end of the distal end 21, and the proximal end of the region 37 that is not inserted into the indwelling device 10 is connected, for example, to the distal end of the proximal end of the inner catheter 20. In this embodiment, the flexible portion 30 is disposed, for example, over the entire area of ​​the region 36 in the intermediate portion 35 through which the indwelling device 10 is inserted. On the other hand, the region 37 of the intermediate section 35 that is not inserted into the indwelling device 10, and the distal end 21 and proximal end of the inner catheter 20 are, for example, regions where the flexible section 30 is not formed. Therefore, while the flexibility of the flexible portion 30 is ensured, good pushability of the inner catheter 20 can be achieved. The flexible portion 30 may be formed, for example, in a portion of the region 36 in the intermediate portion 35 that is inserted into the retention device 10, or may be formed in multiple portions that are not continuous with each other in the longitudinal direction, or may even be present in the tip portion 21 or in the region 37 that is not inserted into the retention device 10.

[0023] In this embodiment, the flexible portion 30 has a smaller diameter than, for example, a portion of the inner catheter 20 that is distal to the flexible portion 30 (the distal portion 21 in this embodiment). Similarly, the flexible portion 30 has a smaller diameter than a portion 27 of the inner catheter 20 that is proximal to the flexible portion 30. That is, the outer diameter of the flexible portion 30 is set to a dimension smaller than, for example, the outer diameter of the portion of the inner catheter 20 that is distal to the flexible portion 30 (the distal portion 21) and the portion 27 of the inner catheter 20 that is proximal to the flexible portion 30. This allows the bending rigidity of the flexible portion 30 to be lowered, so that when the inner catheter 20 is inserted into the indwelling device 10, the inner catheter 20 can bend to better follow the shape of the indwelling device 10. More specifically, in the inner catheter 20, the outer diameter of the region 36 (flexible portion 30) that is inserted into the indwelling device 10 is set to a dimension smaller than the outer diameter of each of the tip portion 21 and the region 37 (portion 27 that is proximal to the flexible portion 30) that is not inserted into the indwelling device 10.

[0024] Furthermore, in this embodiment, there is no step in the outer shape at the boundary between the part of the inner catheter 20 that is more distal than the flexible section 30 (the distal section 21 in this embodiment) and the flexible section 30. Similarly, there is no step in the outer shape at the boundary between the part 27 of the inner catheter 20 that is more proximal than the flexible section 30 and the flexible section 30. This makes it possible to reduce the frictional resistance that occurs between the outer peripheral surface of the inner catheter 20 and the inner peripheral surface of the indwelling device 10 when the inner catheter 20 is removed from the indwelling device 10. 4 and 6, in this embodiment, the outer and inner diameters of the boundary 24a between the flexible portion 30 and the distal end portion 21 taper from the distal end side to the proximal end side. Similarly, the outer and inner diameters of the boundary 24b between the flexible portion 30 and the proximal end portion taper from the proximal end side to the distal end side.

[0025] The inner and outer diameters of the flexible section 30 are each approximately constant, for example, regardless of the position in the axial direction. Similarly, the inner and outer diameters of the distal end section 21 (excluding the most distal end section) are each approximately constant, for example, regardless of the position in the axial direction, and the inner and outer diameters of a section 27 of the inner catheter 20 that is on the proximal side of the flexible section 30 are each approximately constant, for example, regardless of the position in the axial direction. However, the inner and outer diameters of the distal end section of the distal end section 21 (the most distal end section of the inner catheter 20) may each be tapered, for example, with the outer and inner diameters decreasing from the proximal end side toward the distal end side. In addition, the outer diameter of the portion of the inner catheter 20 that is distal to the flexible portion 30 (tip portion 21) is set to a dimension equivalent to the outer diameter of the portion 27 of the inner catheter 20 that is proximal to the flexible portion 30, for example.

[0026] In this embodiment, in a profile (hereinafter sometimes simply referred to as a profile) in which the position in the axial direction of the inner catheter 20 is defined as a first axis and the bending rigidity of each part in the axial direction of the inner catheter 20 is defined as a second axis, the bending rigidity changes continuously at the boundary (boundary portion 24a in this embodiment) between the part of the inner catheter 20 that is distal to the flexible section 30 (distal section 21 in this embodiment) and the flexible section 30, and the bending rigidity of the distal section (distal section 21) is higher than that of the flexible section 30. In addition, the bending rigidity also changes continuously at the boundary (boundary portion 24b in this embodiment) between the part 27 of the inner catheter 20 that is proximal to the flexible section 30 and the flexible section 30, and the bending rigidity of the proximal section (proximal end) is higher than that of the flexible section 30. That is, the bending rigidity of the inner catheter 20 changes continuously without any steps at the boundary between the flexible section 30 and the portion (tip section 21) distal to the flexible section 30. Similarly, the bending rigidity of the inner catheter 20 changes continuously without any steps at the boundary between the flexible section 30 and the portion 27 proximal to the flexible section 30. This results in a configuration in which the bending rigidity of the inner catheter 20 changes gradually from the flexible portion 30 toward the distal end 21, and also in which the bending rigidity of the inner catheter 20 changes gradually from the flexible portion 30 toward the proximal end. Therefore, when the inner catheter 20 is inserted into the indwelling device 10, the inner catheter 20 can bend while more effectively following the shape of the indwelling device 10.

[0027] In this embodiment, as shown in FIG. 6, the plurality of voids 25 are arranged dispersedly in the circumferential and axial directions. This allows the inner catheter 20 to be given flexibility in a well-balanced manner over the entire area in which the plurality of voids 25 are dispersed. In FIG. 6, the shapes of the plurality of voids 25 are shown schematically.

[0028] In this embodiment, the plurality of voids 25 extend, for example, in the circumferential direction. In other words, the plurality of voids 25 are elongated, for example, in the circumferential direction. This can better ensure the radial flexibility of the inner catheter 20. Therefore, the inner catheter 20 can be more easily bent in a direction intersecting the axial direction.

[0029] However, in the present invention, the plurality of voids 25 is not limited to this example, and may, for example, each extend in the axial direction. In other words, the plurality of voids 25 may, for example, be elongated in the axial direction. This configuration also ensures better radial flexibility of the inner catheter 20. Therefore, the inner catheter 20 can be more easily bent in a direction intersecting the axial direction.

[0030] In this embodiment, as shown in Figure 7, the flexible portion 30 has a pair of wall surfaces 28 facing each other with a gap 25 between them, and the shapes of the pair of wall surfaces 28 when viewed in the opposing direction of the pair of wall surfaces 28 are substantially identical to each other. More specifically, a gap 25 is formed by the pair of wall surfaces 28 in the resin of the inner catheter 20. In other words, the gap 25 is defined by the pair of wall surfaces 28. However, in the present invention, the flexible portion 30 does not necessarily have to have a pair of wall surfaces 28, and the void 25 may be, for example, substantially spherical or in some other shape.

[0031] 6 and 7, the vertical cross-sectional shape of each of the pair of wall surfaces 28 is, for example, a complex shape including a plurality of projections and recesses. More specifically, the vertical cross-sectional shape of each of the pair of wall surfaces 28 is not, for example, a linear shape extending in the circumferential direction, but is typically a shape that is bent in multiple directions. More specifically, the longitudinal cross-sectional shape of the assembly of the pair of wall surfaces 28 has a width dimension (dimension in the axial direction) that gradually narrows toward both ends in the extension direction of the assembly. One end of one of the pair of wall surfaces 28 in the extension direction is connected to one end of the other wall surface 28 in the extension direction. Similarly, the other end of one of the pair of wall surfaces 28 in the extension direction is connected to the other end of the other wall surface 28 in the extension direction. However, in the present invention, the vertical cross-sectional shape of the assembly of the pair of wall surfaces 28 is not particularly limited, and may be, for example, a shape other than the above. In this embodiment, the plate surfaces of the pair of wall surfaces 28 face, for example, approximately in the axial direction, and therefore the opposing direction of the pair of wall surfaces 28 is approximately in the axial direction. However, in the present invention, the opposing direction of the pair of wall surfaces 28 is not limited to approximately in the axial direction, and may be approximately in the radial direction or another direction, as described below. In this embodiment, it is preferable that the flexible portion 30 has such a pair of wall surfaces 28 in at least a part of the gap 25. In other words, the flexible portion 30 does not necessarily have to have such a pair of wall surfaces 28 throughout the entire gap 25.

[0032] The flexible portion 30 also has, for example, a plurality of string-like portions 29 connecting the pair of wall surfaces 28 together. This ensures sufficient tensile strength of the inner catheter 20 in the opposing direction of the pair of wall surfaces 28. In this embodiment, as described above, the pair of wall surfaces 28 are disposed substantially opposite each other in the axial direction. Therefore, each string-like portion 29 extends in a direction having an axial component. One end of each string-like portion 29 in the extending direction is connected to one of the pair of wall surfaces 28, and the other end of the string-like portion 29 in the extending direction is connected to the other of the pair of wall surfaces 28. With this configuration, it is possible to ensure sufficient tensile strength of the inner catheter 20 in the axial direction. Each string-like portion 29 may be, for example, straight or curved. Also, a portion of each string-like portion 29 may be branched in multiple directions.

[0033] The method for forming such a void 25 is not particularly limited, but may include, for example, a method of forming it by pulling the molded body of the inner catheter 20 in the axial direction, or a method of mixing a foaming agent into the resin when molding the inner catheter 20. Furthermore, when the gap 25 is formed by pulling the inner catheter 20 in the axial direction, the inner diameter of the flexible portion 30 becomes smaller than the inner diameter of the tip portion 21 and the portion 27 of the inner catheter 20 that is closer to the base end than the flexible portion 30. Furthermore, when the voids 25 are formed by a method of mixing a foaming agent in the resin, the inner diameter of the flexible portion 30 may be smaller than the inner diameters of the tip portion 21 and the portion 27 of the inner catheter 20 that is closer to the base end than the flexible portion 30, or may be equal to these inner diameters. Similarly, in this case, the outer diameter of the flexible portion 30 may be smaller than the outer diameters of the tip portion 21 and the portion 27 of the inner catheter 20 that is closer to the base end than the flexible portion 30, or may be equal to these outer diameters.

[0034] When the flexible section 30 is formed by pulling the molded body of the inner catheter 20 in the axial direction, a plurality of voids 25 are arranged in the flexible section 30, dispersed in the circumferential and axial directions. As an example, each of the plurality of voids 25 extends in the circumferential direction. Each void 25 has a pair of wall surfaces 28 that face each other approximately in the axial direction, and a plurality of string-like portions 29 connecting the pair of wall surfaces 28. On the other hand, when the flexible portion 30 is formed by a method of mixing a foaming agent in a resin, the foaming agent is oriented so that the axial direction and the longitudinal direction of the foaming agent are substantially aligned when the inner catheter 20 is molded (for example, by extrusion molding), and therefore the formed voids 25 also have a shape extending in the axial direction. Each void 25 has, for example, a pair of wall surfaces 28 that face each other approximately in the radial direction, and a plurality of string-like portions 29 connecting the pair of wall surfaces.

[0035] In this embodiment, the bending rigidity of the flexible portion 30 can be changed by adjusting the occupancy rate of the voids 25 per unit area in the resin. More specifically, increasing the occupancy rate of voids 25 per unit area in the resin can reduce the bending rigidity of the flexible section 30. On the other hand, decreasing the occupancy rate of voids 25 per unit area in the resin can increase the bending rigidity of the flexible section 30. Therefore, the bending rigidity of the inner catheter 20 can be appropriately set according to the bending rigidity and dimensions of the indwelling device 10, and therefore, deformation of the indwelling device 10 into the shape of the inner catheter 20 can be more reliably prevented. In addition, by adjusting the occupancy rate of voids 25 per unit area in the resin at the boundaries 24a, 24b, the gradient of the above profile at the boundaries 24a, 24b (parts where the bending rigidity changes continuously) can be changed. More specifically, the gradient of the profile can be reduced by configuring the occupancy rate of voids 25 per unit area at boundaries 24a, 24b to gradually decrease from the flexible portion 30 side toward the distal end 21 side and the proximal end side. On the other hand, the gradient of the profile can be increased by configuring the occupancy rate of voids 25 per unit area at boundaries 24a, 24b to sharply decrease from the flexible portion 30 side toward the distal end 21 side and the proximal end side. This makes it possible to realize, for example, a configuration in which the bending rigidity of the inner catheter 20 gradually changes from the flexible portion 30 toward the tip portion 21 and the base end, or a configuration in which the bending rigidity suddenly changes from the flexible portion 30 toward the tip portion 21 or the base end. When forming voids 25 by pulling the inner catheter 20 in the axial direction, methods for adjusting the occupancy rate of voids 25 per unit area in the resin can be, for example, by adjusting the tensile load, pulling speed, temperature, internal tube pressure, etc. Alternatively, as a method for adjusting the occupancy rate of voids 25 per unit area in the resin, when voids 25 are formed by mixing a foaming agent into the resin of the inner catheter 20, for example, a method can be used in which the amount of foaming agent mixed in or the processing temperature is adjusted in the axial direction.

[0036] In addition, by adjusting the axial dimensions of the boundary portions 24a, 24b, it is possible to achieve, for example, a configuration in which the bending rigidity of the inner catheter 20 changes abruptly from the flexible portion 30 toward the tip portion 21 and the base end, or a configuration in which the bending rigidity changes gradually from the flexible portion 30 toward the tip portion 21 and the base end. As a method for adjusting the axial dimensions of the boundaries 24a, 24b, when the gap 25 is formed by pulling the inner catheter 20 in the axial direction, for example, a method can be used in which the distance between the clamped portions of the inner catheter 20 and the temperature are adjusted when pulling the inner catheter 20 in the axial direction. Alternatively, as a method for adjusting the axial dimensions of the boundary portions 24a, 24b, when the void 25 is formed by mixing a foaming agent into the resin of the inner catheter 20, for example, a method can be used in which the amount of foaming agent mixed in or the processing temperature is adjusted in the axial direction.

[0037] The inner catheter 20 is integrally molded entirely from a fluorine-based resin with low frictional resistance, such as polytetrafluoroethylene, but may also be made of a resin material such as polyurethane, polyethylene, silicone, polyamide, polyamideimide, vinyl chloride, or polyethersulfone. This configuration reduces the sliding resistance of the inner catheter 20 against the inner wall of a biological organ when it is moved within the biological organ. Furthermore, since the flexible portion 30, the portion distal to the flexible portion 30 (the distal portion 21), and the portion proximal to the flexible portion 30 are integrally formed from a common resin material, the flexible portion 30, the distal portion 21, and the portion proximal to the flexible portion 30 can be well maintained in a joined state at the boundaries 24 a and 24 b.

[0038] The total length of the inner catheter 20 is not particularly limited as long as it can be inserted over at least the entire length of the indwelling device 10 . More specifically, the total length of the inner catheter 20 is, for example, preferably 350 mm or more and 5000 mm or less, and more preferably 500 mm or more and 2000 mm or less. The length dimension (dimension in the axial direction) of the flexible portion 30 is not particularly limited, but is preferably 20 mm or more and 250 mm or less, and more preferably 30 mm or more and 100 mm or less. The outer diameter of the flexible portion 30 is not particularly limited, but is preferably 0.5 mm or more and 2.5 mm or less, and more preferably 0.8 mm or more and 2.0 mm or less. The outer diameter of each of the distal end portion 21 and the proximal end portion is not particularly limited, but is preferably 0.8 mm or more and 3.0 mm or less, and more preferably 1.0 mm or more and 2.5 mm or less. The dimension of each of the boundaries 24a, 24b in the axial direction is not particularly limited, but is preferably 0.1 mm or more and 100 mm or less, and more preferably 0.2 mm or more and 50 mm or less. However, the length, outer diameter, and inner diameter of each part of the inner catheter 20 may be set to dimensions other than those described above depending on the application of the medical device 100, etc.

[0039] As shown in FIG. 1, in this embodiment, the medical device 100 further includes, for example, a pusher catheter 40 and an operation section 50 connected to the proximal end of the pusher catheter 40. The pusher catheter 40 is a long, hollow tubular member. The pusher catheter 40 is attached to the inner catheter 20 so as to be detachable from the inner catheter 20, for example. The inner diameter of the pusher catheter 40 is set to be larger than the outer diameter of the inner catheter 20 . The outer diameter of the pusher catheter 40 is set to, for example, a dimension substantially equal to the outer diameter of the indwelling device 10 . The operation section 50 includes, for example, a first member 51 connected to the proximal end of the pusher catheter 40 and a second member 52 connected to the proximal end of the inner catheter 20. The first member 51 is formed, for example, in a cylindrical shape through which the inner catheter 20 can be inserted. The inner diameter of the first member 51 is set to a dimension larger than the outer diameter of the inner catheter 20. Therefore, the inner catheter 20 can be inserted into the lumen of the first member 51. The proximal end of the pusher catheter 40 is connected to the distal end of the first member 51, and the lumen of the first member 51 communicates with the lumen of the pusher catheter 40 via an opening on the distal end side of the first member 51. The second member 52 is formed in a cylindrical shape, for example, so that a guide wire, which will be described later, can be inserted therethrough. The second member 52 is, for example, removably attached to the first member 51. With the second member 52 attached to the first member 51, the inner catheter 20 is inserted into the pusher catheter 40 and the indwelling device 10 through the lumen of the first member 51. The pusher catheter 40 is disposed closer to the proximal end than the indwelling device 10 , and the end face on the proximal end side of the indwelling device 10 faces the end face on the distal end side of the pusher catheter 40 .

[0040] Although there are no particular limitations on the material of the pusher catheter 40, it is preferable to use a fluororesin with low friction resistance, such as polytetrafluoroethylene, which can reduce the sliding resistance of the pusher catheter 40 against the inner wall of the biological organ when it is moved inside the biological organ.

[0041] Here, a connecting member (not shown) made of, for example, a string-like member may be connected to the base end of the indwelling device 10. The base end of the connecting member is fixed to the tip edge of the pusher catheter 40. That is, the indwelling device 10 and the pusher catheter 40 are connected to each other via the connecting member. The tip end of the connecting member is held between the outer circumferential surface 20b of the inner catheter 20 and the inner circumferential surface 10a of the indwelling device 10. When the inner catheter 20 is removed from the indwelling device 10, the connection of the connecting member to the indwelling device 10 is released, and the connection between the indwelling device 10 and the pusher catheter 40 can be released.

[0042] For example, it is also preferable that a hydrophilic agent be coated on the outer circumferential surface of the pusher catheter 40 and the outer circumferential surface of the inner catheter 20. This reduces the sliding resistance of the pusher catheter 40 and the inner catheter 20 against the inner wall of the biological organ, improving the operability of the medical device 100.

[0043] In this embodiment, the medical device 100 is, before use, housed in a package (not shown) in a sterilized state, for example. In this state, the inner catheter 20 is inserted into the lumen of the indwelling device 10. As described above, in this embodiment, the inner catheter 20 is inserted into the bent portion 15 of the indwelling device 10, and at least a portion of the portion inserted into the bent portion 15 is the flexible portion 30. Therefore, even if the medical device 100 is stored for a long period of time with the inner catheter 20 inserted into the indwelling device 10, the natural shape of the indwelling device 10 can be well maintained.

[0044] In the following, an example will be described in which the medical device 100 is used in a procedure for placing the indwelling device 10 inside a bile duct (not shown). The description will be given starting from a state in which the tip of the insertion portion of the endoscope (not shown) is placed inside the duodenum (not shown) near the duodenal papilla (papilla of Vater), a needle hole is formed in the bile duct (not shown), and the tip of the guidewire (not shown) is placed (anchored) in the needle hole. First, the medical device 100 is introduced along the guidewire. More specifically, the inner catheter 20 is inserted onto the guidewire, and the inner catheter 20 is fed into the pinhole while sliding from the base end to the tip end along the axial direction of the guidewire. At this time, the indwelling device 10 is deformed into a substantially linear shape along the guidewire against the elastic restoring force. Next, the indwelling device 10 is fed into the bile duct while sliding from the base end to the tip end along the inner catheter 20. Here, for example, the tip end 11 and the intermediate portion 13 of the indwelling device 10 are positioned inside the bile duct via the duodenal papilla, and the base end 12 of the indwelling device 10 is positioned inside the duodenum near the duodenal papilla. Next, the indwelling device 10 is placed in this state. More specifically, the guide wire and the inner catheter 20 are each withdrawn (removed) from the indwelling device 10 by retracting them. Then, the bent portion 15 (distal end 11 and proximal end 12) of the indwelling device 10 returns to its natural shape, i.e., the arc-shaped shape shown in FIG. 3 , or a shape close to this natural shape, due to elastic restoring force. As a result, the arc-shaped distal end 11 is engaged with the inner wall of the bile duct, and the arc-shaped proximal end 12 is engaged with the duodenal papilla inside the duodenum. When the inner catheter 20 is retracted, the retraction of the indwelling device 10 is restricted by the pusher catheter 40 arranged on the proximal end side of the indwelling device 10.

[0045] Although the embodiments have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations can also be adopted.

[0046] The present embodiment encompasses the following technical ideas. (1) A medical device having a tubular indwelling device and an inner catheter inserted into the indwelling device, the inner catheter is a resin tube, In the inner catheter, the region where the indwelling device is inserted has multiple voids scattered throughout the resin, and the medical device has a flexible portion that can be easily bent in a direction intersecting the axial direction of the inner catheter. (2) The medical device according to (1), wherein the plurality of voids are dispersed and arranged in the circumferential and axial directions. (3) The medical device according to (2), wherein each of the plurality of voids extends in a circumferential direction. (4) The medical device according to (2), wherein each of the plurality of voids extends in the axial direction. (5) The flexible portion has a pair of wall surfaces facing each other with the gap therebetween, The medical device according to any one of (1) to (4), wherein the pair of wall surfaces have substantially the same shape when viewed in the opposing direction of the pair of wall surfaces. (6) The medical device according to (5), wherein the flexible portion has a plurality of string-like portions connecting the pair of wall surfaces. (7) A medical device according to any one of (1) to (6), wherein the lumen of the inner catheter is liquid-tightly shielded from the outside by a tube wall of the inner catheter. (8) The flexible portion is disposed in an intermediate portion of the inner catheter in the axial direction, In the inner catheter, there is no step in the outer shape at the boundary between the distal end portion of the flexible portion and the flexible portion, The medical device according to any one of (1) to (7), wherein the inner catheter has no step in its outer shape at the boundary between the flexible portion and a portion of the inner catheter that is closer to the base end than the flexible portion. (9) The flexible portion is disposed in an intermediate portion of the inner catheter in the axial direction, The medical device according to (8), wherein the flexible portion has a smaller diameter than the portion of the inner catheter that is distal to the flexible portion, and a smaller diameter than the portion of the inner catheter that is proximal to the flexible portion. (10) The flexible portion is disposed in an intermediate portion in the axial direction of the inner catheter, Regarding a profile in which the position in the axial direction of the inner catheter is defined as a first axis and the bending rigidity of each part in the axial direction of the inner catheter is defined as a second axis, the bending rigidity of the inner catheter changes continuously at a boundary between the flexible portion and a portion of the inner catheter that is distal to the flexible portion, and the bending rigidity of the distal portion is higher than that of the flexible portion; A medical device according to any one of (1) to (9), wherein the bending rigidity of the inner catheter changes continuously even at the boundary between the flexible portion and the portion closer to the base end than the flexible portion, and the portion closer to the base end has a higher bending rigidity than the flexible portion. [Explanation of symbols]

[0047] 10 Detention Device 10a Inner surface 10b Outer surface 11 Tip 12 Proximal end 13 Middle section 15 Bend 17 Opening 19 Marking section 20 Inner catheter 21 Tip (the part closer to the tip than the flexible part) 24a, 24b border 25 void 27 The part closer to the base than the flexible part 28 Pair of Walls 29 Cord-like portion 30 Flexible section 35 Middle section 36 Area where the device is inserted 37 Area not penetrated by the device 40 Pusher Catheter 50 Control section 51 First member 52 Second member 100 Medical equipment

Claims

1. A medical device having a tubular indwelling device and an inner catheter inserted into the indwelling device, the inner catheter is a resin tube, In the inner catheter, a region inserted into the indwelling device has a flexible portion including a plurality of voids scattered in a resin constituting the resin tube, The flexible portion of the medical device is easily bent in a direction intersecting the axial direction of the inner catheter due to the plurality of voids scattered throughout the resin.

2. The medical device according to claim 1 , wherein the plurality of voids are arranged dispersedly in the circumferential and axial directions.

3. The medical device according to claim 2 , wherein each of the plurality of voids extends in a circumferential direction.

4. The medical device according to claim 2 , wherein each of the plurality of voids extends in an axial direction.

5. the flexible portion has a pair of wall surfaces facing each other with the gap therebetween, The medical device according to claim 1 , wherein the pair of wall surfaces have substantially the same shape when viewed in the opposing direction.

6. The medical device according to claim 5 , wherein the flexible portion has a plurality of string-like portions connecting the pair of wall surfaces together.

7. The medical device according to any one of claims 1 to 6, wherein the lumen of the inner catheter is liquid-tightly shielded from the outside by a tube wall of the inner catheter.

8. the flexible portion is disposed at an intermediate portion in the axial direction of the inner catheter, In the inner catheter, there is no step in the outer shape at the boundary between the distal end portion of the flexible portion and the flexible portion, The medical device according to claim 1 , wherein the boundary between the flexible portion and a portion of the inner catheter that is closer to the base end than the flexible portion does not have a step in its outer shape.

9. the flexible portion is disposed at an intermediate portion in the axial direction of the inner catheter, The medical device according to claim 8, wherein the flexible portion has a smaller diameter than a portion of the inner catheter that is distal to the flexible portion and that is proximal to the flexible portion.

10. the flexible portion is disposed at an intermediate portion in the axial direction of the inner catheter, Regarding a profile in which the position in the axial direction of the inner catheter is defined as a first axis and the bending rigidity of each part in the axial direction of the inner catheter is defined as a second axis, the bending rigidity of the inner catheter changes continuously at a boundary between the flexible portion and a portion of the inner catheter that is distal to the flexible portion, and the bending rigidity of the distal portion is higher than that of the flexible portion; The medical device according to any one of claims 1 to 9, wherein the bending rigidity of the inner catheter changes continuously even at the boundary between the portion of the inner catheter that is more proximal than the flexible portion and the flexible portion, and the portion of the inner catheter that is more proximal than the flexible portion has a higher bending rigidity.

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