Method for manufacturing a medical device and an extension body

Abstract

Provided are: a medical device having an expandable body which is capable of expanding in the radial direction, is prevented from being twisted and bent in the circumferential direction, and enables effective transmission of force to a biological tissue; and a method for producing an expandable body for use in a medical device.　A medical device (10) has: an outer tube (20); an expandable body (40) capable of expanding in the radial direction; and a pulling shaft (60) that protrudes from the distal end of the outer tube (20), is connected to the distal end of the expandable body (40), and is able to slide relative to the outer tube (20). The expandable body (40) has main struts (41) and sub struts (56). The main struts (41) are substantially parallel to the axis when viewed from the outside in the radial direction. The sub struts (56) have at least two joint sections each joined to two main struts (41) adjacent in the circumferential direction. At least two of the joint sections are disposed at different positions in the axial direction of the outer tube (40). The radially outermost position of the main struts (41) is located on the outer side of the radially outermost position of the sub struts (56).

Description

Technical Field

[0001] The present invention relates to a medical device for expanding a lumen or a hole of a living body or clamping a living tissue, and a method for manufacturing an expander used in the medical device.

Background Art

[0002] In recent years, a device that is inserted into a living body lumen such as a blood vessel to expand the lumen or hole of the living body has been used. For example, Patent Document 1 describes a catheter including a basket-shaped electrode assembly for mapping the electrical activity of the heart. The proximal end portion of the electrode assembly is fixed to the distal end portion of the outer tube, and the distal end portion of the electrode assembly is fixed to the distal end portion of the inner tube that penetrates the outer tube. The electrode assembly has a plurality of wire members that extend along the axial center of the inner tube and are convexly curved outward in the radial direction, and electrodes disposed on each wire member. The plurality of wire members are substantially parallel to the axial center of the electrode assembly when viewed from the outer side in the radial direction. By pulling the inner tube, the wire members of the electrode assembly are contracted in the axial direction, greatly bent, and protrude outward in the radial direction. Thereby, the electrodes disposed on the wire members are pressed against the living tissue.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the wire member that is substantially parallel to the axial center when viewed from the outer side in the radial direction is contracted in the axial direction of the electrode assembly, torsional deflection in the circumferential direction centered on the axial center of the electrode assembly is likely to occur. As a result, the force for contracting the wire member is dispersed, making it difficult to effectively transmit the force to the tissue.

[0005] The present invention has been made to solve the above-described problems, and suppresses circumferential torsion and bending of an expandable body that can expand in the radial direction, and can effectively transmit force to living tissue by the expandable body. An object of the present invention is to provide a medical device and a method for manufacturing an expandable body used in the medical device.

Means for Solving the Problems

[0006] The medical device according to the present invention that achieves the above object is connected to the tip of the outer tube, and is an expandable body that expands in the radial direction by contracting along the axis of the outer tube, and is disposed inside the outer tube. And a traction shaft that protrudes from the tip of the outer tube and is connected to the tip of the expandable body and is slidable with respect to the outer tube. The expandable body is arranged at intervals in the circumferential direction and extends a predetermined length along the axis of the outer tube. A plurality of main struts, and a plurality of sub-struts connected to the plurality of main struts. Each of the plurality of main struts is substantially parallel to the axis when viewed from the outside in the radial direction. Each of the plurality of sub-struts has at least two joints joined to each of two adjacent main struts in the circumferential direction among the plurality of main struts. At least two of the joints are arranged at different positions in the axial direction of the outer tube. In a cross section perpendicular to the axis of the expandable body at any position where the sub-strut exists, the outermost position in the radial direction of the main strut in the natural state is located outside the outermost position in the radial direction of the sub-strut. The main strut has an outward convex portion that protrudes radially outward, the secondary strut is connected to the main strut on the tip side and the base end side of the outward convex portion, and in a cross-section perpendicular to the axis at the position where the outward convex portion is provided, the position of the outward convex portion in the natural state is located outside the outermost position in the radial direction of the secondary strut. It is characterized by doing so. Another aspect of the medical device according to the present invention that achieves the above object is connected to the tip of the outer tube, and an expandable body that expands radially by contracting along the axis of the outer tube, and is disposed inside the outer tube, and protrudes from the tip of the outer tube and is connected to the tip of the expandable body, and has a traction shaft slidable with respect to the outer tube. The expandable body has a plurality of main struts arranged at intervals in the circumferential direction and extending a predetermined length along the axis of the outer tube, and a plurality of secondary struts connected to the plurality of main struts. Each of the plurality of main struts is substantially parallel to the axis when viewed from the outside in the radial direction, and each of the plurality of secondary struts has at least two joints joined to each of two adjacent main struts in the circumferential direction among the plurality of main struts. At least two of the joints are arranged at different positions in the axial direction of the outer tube. In a cross-section perpendicular to the axis of the expandable body at any position where the secondary strut exists, the outermost position in the radial direction of the main strut in the natural state is located outside the outermost position in the radial direction of the secondary strut. The main strut has a tip-side clamping strut and a base-end-side clamping strut whose separation distance decreases as the expandable body expands, and an inward convex portion that protrudes radially inward is formed between the tip-side clamping strut and the base-end-side clamping strut, and the secondary strut is arranged on at least one of the tip side or the base end side of the inward convex portion.

Effects of the Invention

[0007] The medical device configured as described above can suppress the circumferential twist of the main struts that expand radially and act on the tissue by receiving traction force by the secondary struts. Note that, since the secondary struts change the inclination angle when the circumferential distance between the two main struts to which the secondary struts are connected increases, the secondary struts tend to be shorter in the axial direction than the main struts. However, in a cross-section perpendicular to the axis, since the outermost position in the radial direction of the main struts is located outside the outermost position in the radial direction of the secondary struts, it is possible to suppress the secondary struts from becoming shorter in the axial direction than the main struts and reduce the influence on the main struts. That is, the secondary struts located on the inner side in the radial direction can connect the two main struts arranged in the circumferential direction at a shorter distance than when the secondary struts are located on the outer side in the radial direction. For this reason, it is possible to suppress the main struts to which the secondary struts are connected at a plurality of positions in the axial direction from being bent too much by receiving a tensile force from the secondary struts when the expandable body expands. For this reason, in the medical device, the force pressing the expandable body against the biological tissue is less likely to be dispersed, and it is possible to effectively transmit the force to the biological tissue by the expandable body.

[0008] The plurality of secondary struts each extend from each of the two main struts adjacent in the circumferential direction, and include two inclined struts inclined with respect to the axis when viewed from the outer side in the radial direction, and a confluence portion where the two inclined struts are connected. The two inclined struts connected to the confluence portion may be symmetric with respect to a plane passing through the confluence portion and the axis of the expandable body. Thereby, when the expandable body is deformed, the two inclined struts that are plane-symmetric are deformed into symmetric shapes. For this reason, the forces acting from the inclined struts on the two main struts adjacent in the circumferential direction become equal. Therefore, it is possible to suppress the occurrence of circumferential twist in the main struts.

[0009] Of the inclined struts provided on each of the auxiliary struts, two are tip-side inclined struts that are arranged side by side in the circumferential direction between two circumferentially adjacent main struts and are connected to the main struts. The two inclined struts provided on each of the auxiliary struts are located on the base end side rather than the tip side of the tip-side inclined struts, and are base-end side inclined struts that are arranged side by side in the circumferential direction between two circumferentially adjacent main struts and are connected to the main struts. Each auxiliary strut may have a confluence portion that connects the tip-side inclined strut and the base-end side inclined strut. Thereby, the deflection of the main strut can be suppressed. For this reason, in the medical device, the force for pressing the expandable body against the living tissue is less likely to be dispersed, and it is possible to effectively transmit the force to the living tissue by the expandable body.

[0010] The main strut has an outward convex portion that protrudes outward in the radial direction. The auxiliary strut is connected to the main strut on the tip side and the base end side rather than the outward convex portion. In a cross section perpendicular to the axis at the position where the outward convex portion is provided, the position of the outward convex portion in the natural state may be located outside the position that is the outermost in the radial direction of the auxiliary strut. Thereby, when the expandable body expands, while protruding the outward convex portion of the main strut, it is possible to effectively suppress that a portion other than the outward convex portion of the main strut receives a tensile force from the auxiliary strut and is excessively deflected. For this reason, in the medical device, the force for pressing the expandable body against the tissue is less likely to be dispersed, and it is possible to effectively transmit the force to the living tissue by the expandable body.

[0011] The main struts have a tip-side clamping strut and a base-side clamping strut whose separation distance decreases as the expander expands. An inner convex portion that protrudes radially inward is formed between the tip-side clamping strut and the base-side clamping strut. The sub-strut may be disposed on at least one of the tip side or the base side of the inner convex portion. Thereby, it is possible to effectively suppress the portions on the tip side and the base side of the inner convex portion from being excessively deflected by receiving a tensile force from the sub-strut. For this reason, in the medical device, the force for gripping the tissue by the tip-side clamping strut and the base-side clamping strut is less likely to be dispersed, and the living tissue can be effectively gripped.

[0012] The medical device may have an energy transmission element disposed on the expander to output energy. Thereby, the medical device can perform cauterization by the energy transmission element in a state where a body lumen or hole is expanded to a desired size by the expander whose excessive deflection is suppressed.

[0013] A method for manufacturing an expander according to the present invention that achieves the above object is a method for manufacturing an expander having a tip portion and a base portion, the method including: preparing an expander having a plurality of main struts arranged at intervals in the circumferential direction and extending a predetermined length along an axis passing through the tip portion and the base portion, and a plurality of sub-struts connected to the plurality of main struts; disposing, inside the expander, a jig in which a plurality of small-diameter portions and a plurality of large-diameter portions having an outer diameter larger than that of the small-diameter portions are alternately arranged in the circumferential direction; disposing the plurality of main struts outside the plurality of large-diameter portions in the radial direction to deform the plurality of main struts into a shape along the plurality of large-diameter portions, and disposing the plurality of sub-struts outside the plurality of small-diameter portions in the radial direction to deform the sub-struts into a shape along the plurality of small-diameter portions.

[0014] The method for manufacturing an expander configured as described above can manufacture an expander in which the position of the main strut that is the outermost in the radial direction in the natural state is disposed outside the position of the sub-strut that is the outermost in the radial direction.

[0015] When manufacturing the extension body, when deforming the plurality of main struts and the plurality of sub-struts, the plurality of main struts may be pressed against the plurality of large-diameter portions, and the plurality of sub-struts may be pressed against the plurality of small-diameter portions, respectively. Thereby, the plurality of main struts and the plurality of sub-struts can be easily formed into a desired shape by the large-diameter portions and the small-diameter portions.

[0016] The jig has a first jig disposed inside the tip side of the extension body and a second jig disposed inside the base end side of the extension body. At least one of the first jig and the second jig has the plurality of small-diameter portions and the plurality of large-diameter portions. The first jig has a first inclined surface at its base end portion, and the outer diameter of the first jig decreases as it goes toward the base end. The second jig has a second inclined surface at its tip portion, and the outer diameter of the second jig decreases as it goes toward the tip. When the jig is disposed inside the extension body, a constricted portion constricted inward is formed from the first inclined surface and the second inclined surface, and the plurality of main struts and the plurality of sub-struts may be pressed against the constricted portion to deform them into a shape along the constricted portion. Thereby, it becomes easy to form an inward convex portion protruding radially inward in the main strut.

[0017] The first jig and the second jig are spaced apart when the jig is disposed inside the extension body, and may contact each other when deforming the plurality of main struts and the plurality of sub-struts into a shape along the constricted portion. Thereby, by bringing the first jig and the second jig into contact with each other, it becomes easy to obtain an accurate relative positional relationship. For this reason, the extension body can be easily formed into a desired shape.

Brief Description of the Drawings

[0018]

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Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the dimensional ratios in the drawings may be exaggerated for convenience of explanation and may differ from the actual ratios. In this specification, the side inserted into the body cavity of the medical device 10 will be referred to as the "tip side", and the operating side will be referred to as the "base end side".

[0020] As shown in FIG. 7, the medical device according to the present embodiment is configured to be able to expand a through hole Hh formed in the atrial septum HA of the patient's heart H and perform a maintenance treatment to maintain the expanded through hole Hh at its size.

[0021] As shown in FIGS. 1 and 2, the medical device 10 of the present embodiment includes a long outer tube 20, a storage sheath 30 for housing the outer tube 20, an expander 40 provided at the tip of the outer tube 20, and a traction shaft 60 for pulling the expander 40. The medical device 10 further includes an operation unit 80 provided at the base end of the outer tube 20 and an energy transmission element 90 disposed on the expander 40 for performing the above-described maintenance treatment.

[0022] The tip of the outer tube 20 is fixed to the base end of the expander 40. The base end of the outer tube 20 is fixed to the operation unit 80.

[0023] The storage sheath 30 is movable back and forth in the axial direction (direction along the axis) with respect to the outer tube 20. The storage sheath 30 can house the expander 40 inside it in a state where it has moved to the tip side of the outer tube 20. The storage sheath 30 can expose the expander 40 by moving it to the base end side from the state of housing the expander 40.

[0024] As shown in Figures 2 to 4, the traction shaft 60 has a traction tube 61 that can move back and forth in the axial direction inside the outer tube 20, and a widening portion 62 fixed to the tip end of the traction tube 61. The base end of the traction tube 61 is led out toward the base end side from the operation section 80. The traction tube 61 has a lumen formed along the axial direction, through which the guide wire 11 and the balloon catheter 12 (see Figures 9 to 11) can be inserted.

[0025] The expanding portion 62 is movable inside the expansion body 40 along the axis of the expansion body 40. The expanding portion 62 has a base end connecting portion 63 fixed to the tip portion of the traction tube 61, a plurality of base end wires 64 extending from the base end connecting portion 63 in the distal direction, a link portion 65 extending from the base end wires 64 in the distal direction and connecting the base end wires 64 to each other, and a plurality of sub-wires 69 extending from the link portion 65 in the distal direction. At least a portion of the expanding portion 62 is located on the distal side of the outer tube 20.

[0026] The multiple base end wires 64 are arranged evenly in the circumferential direction around the axis of the expansion body 40. The number of base end wires 64 is not particularly limited, but is, for example, six.

[0027] The link portion 65 connects adjacent base wires 64 arranged in the circumferential direction, and connects adjacent secondary wires 69 arranged in the circumferential direction. The link portion 65 is formed in a honeycomb structure in which a plurality of hexagonal frames are arranged and connected in the circumferential direction around the axis of the expansion body 40. The number of hexagonal frames is, for example, six, which corresponds to the number of base wires 64 and secondary wires 69. The number of hexagonal frames is not particularly limited.

[0028] The link portion 65 has a base end link portion 66 connected to the tip end of the base end wire 64, a tip end link portion 67 connected to the base end of the secondary wire 69, and a plurality of intermediate link portions 68 provided between the tip end link portion 67 and the base end link portion 66.

[0029] The base link portion 66 is formed in an annular shape around the axis of the expandable body 40 while being folded back in a zigzag manner toward the tip side and the base side so as to alternately connect the base end portion of the intermediate link portion 68 and the tip end portion of the base end wire 64.

[0030] The tip link portion 67 is formed in an annular shape around the axis of the expandable body 40 while being folded back in a zigzag manner toward the tip side and the base side so as to alternately connect the tip end portion of the intermediate link portion 68 and the base end portion of the sub-wire 69.

[0031] The intermediate link portions 68 are evenly arranged in the circumferential direction around the axis of the expandable body 40. Each intermediate link portion 68 extends along the axis of the expandable body 40. The base end portion of the intermediate link portion 68 is connected to a portion protruding in the tip direction of the base link portion 66, and the tip end portion of the intermediate link portion 68 is connected to a portion protruding in the base end direction of the tip link portion 67. For this reason, when the connection portions of the intermediate link portion 68 and the base link portion 66 and the connection portions of the intermediate link portion 68 and the tip link portion 67 slide along the axis with respect to other members, they are not caught by other members.

[0032] The link portion 65 formed in a honeycomb structure is tubular and can be expanded and contracted in the radial direction by changing the angles of the hexagonal corners. Note that the link portion 65 does not necessarily have to be formed in a honeycomb structure in which hexagons are arranged, and may be formed in a lattice structure in which rhombuses are arranged, for example.

[0033] The plurality of sub-wires 69 are evenly arranged in the circumferential direction around the axis of the expandable body 40. The number of sub-wires 69 is not particularly limited, but is, for example, six. Each sub-wire 69 has a linear sliding shaft 70 and an engaging portion 71 disposed at the tip end portion of the sliding shaft 70. The sliding shaft 70 is slidable with respect to the expandable body 40. The engaging portion 71 is engageable with the expandable body 40 in order to pull the expandable body 40 in the base end direction. The engaging portion 71 is formed in a T shape, for example, at the tip of the sliding shaft 70 and protrudes in two directions perpendicular to the axis of the expandable body 40 when viewed from the outside in the radial direction. Note that the shape of the engaging portion 71 is not particularly limited as long as it can engage with the expandable body 40.

[0034] The expanding portion 62 is formed such that the inner diameter and the outer diameter expand from the base end portion toward the tip end portion, either entirely or at least partially. The base end portion of the expanding portion 62 can be accommodated in the outer tube 20. And the portion of the expanding portion 62 on the tip end side from the portion accommodated in the outer tube 20 expands radially outward beyond the inner diameter of the outer tube 20. Since the expanding portion 62 is formed in a net shape, it can expand and contract in the radial direction. The expanding portion 62 is formed by subjecting a circular tube, which is the material, to laser processing. Note that the forming method of the expanding portion 62 is not limited to this.

[0035] As shown in FIGS. 2, 3, and 5, the expandable body 40 has a plurality of main struts 41 arranged in the circumferential direction around the axis of the expandable body 40, and a plurality of sub-struts 56 arranged between the main struts 41 adjacent in the circumferential direction. The main struts 41 and the sub-struts 56 are alternately arranged in the circumferential direction. The number of the main struts 41 and the sub-struts 56 is not particularly limited, but is, for example, six. A strut means a columnar member that can support a load.

[0036] Each main strut 41 can expand and contract in the radial direction of the expandable body 40. In the natural state where no external force acts, the expandable body 40 is in a radially expanded form. The base end portion of the main strut 41 is fixed to the tip end portion of the outer tube 20. The main strut 41 has a base end side main strut 42, a base end side clamping strut 43, a tip end side clamping strut 44, a tip end side main strut 45, and a tip end side connecting strut 46. The main strut 41 has the following shape in the deployed form.

[0037] The base end side main strut 42 is inclined so as to increase in the radial direction from the base end portion of the expandable body 40 toward the tip end direction. The tip end side main strut 45 is inclined so as to increase in the radial direction from the tip end side connecting strut 46 located at the tip end portion of the expandable body 40 toward the base end direction. Each of the base end side main strut 42 and the tip end side main strut 45 extends linearly.

[0038] The base-end-side clamping strut 43 is inclined so as to become smaller in the radial direction from the tip of the base-end-side main strut 42 toward the tip direction. The base-end-side clamping strut 43 and the base-end-side main strut 42 are connected by a base-end-side outer convex portion 47 that protrudes outward in the radial direction. The tip-end-side clamping strut 44 is inclined so as to become smaller in the radial direction from the base end of the tip-end-side main strut 45 toward the base end direction. The tip-end-side clamping strut 44 and the tip-end-side main strut 45 are connected by a tip-end-side outer convex portion 48 that protrudes outward in the radial direction. The base-end-side clamping strut 43 and the tip-end-side clamping strut 44 are connected by an inner convex portion 49 that protrudes inward in the radial direction. The distance between the base-end-side clamping strut 43 and the tip-end-side clamping strut 44 is preferably somewhat larger in the axial direction on the outer side than on the inner side in the radial direction in the deployed form. Thereby, it is easy to place biological tissue between the base-end-side clamping strut 43 and the tip-end-side clamping strut 44 from the outer side in the radial direction.

[0039] One intermediate through hole 50 is formed in the main strut 41 near the base end of the tip-end-side main strut 45 and the tip-end-side clamping strut 44. The intermediate through hole 50 penetrates in the radial direction of the expander 40. And the main strut 41 has two outer edge portions 51 sandwiching the intermediate through hole 50 and a backrest portion 52 provided between the two outer edge portions 51. The backrest portion 52 can face an energy transmission element 90 disposed on the base-end-side clamping strut 43 when contracting in the direction along the axis of the expander 40. Each outer edge portion 51 is pulled by a sub-strut 56 described later to have an arc shape in the deployed form. Therefore, a wide area for arranging the backrest portion 52 and the intermediate through hole 50 can be secured between the two outer edge portions 51.

[0040] The abutment portion 52 protrudes between the two outer edge portions 51 from the portion on the inner convex portion 49 side of the distal end side clamping strut 44 toward the base end portion of the distal end side clamping strut 44. The abutment portion 52 is disposed between the two outer edge portions 51 with a space from the two outer edge portions 51. Since the abutment portion 52 has a cantilever beam shape with its base end portion fixed, it is easily bent. For this reason, the abutment portion 52 can be bent more easily than the outer edge portion 51 by the force directed toward the distal end received from the energy transmission element 90 disposed on the proximal end side clamping strut 43.

[0041] A force receiving portion 53 for slidably holding the sliding shaft 70 of the traction shaft 60 is formed at the distal end portion of the distal end side main strut 45. The force receiving portion 53 is a rectangular hole having a long side in the axial direction of the expandable body 40. For this reason, the direction of the long side of the force receiving portion 53 is substantially perpendicular to the direction of the T-shaped engaging portion 71 of the traction shaft 60. Therefore, the force receiving portion 53 can engage with the engaging portion 71 without passing through the engaging portion 71 while slidably holding the sliding shaft 70. The force receiving portion 53 can receive a traction force from the engaging portion 71 by engaging with the engaging portion 71. Note that the T-shaped engaging portion 71 of the sub-wire member 69 can be inserted into the force receiving portion 53 by intentionally twisting the sub-wire member 69 by 90 degrees. Since the plurality of sub-wire members 69 arranged in the circumferential direction are connected by the link portion 65, they are not easily twisted. For this reason, after intentionally twisting the sub-wire member 69 by 90 degrees to insert the T-shaped engaging portion 71 into the force receiving portion 53 and then returning the twist of the sub-wire member 69, the engaging portion 71 becomes unable to pass through the force receiving portion 53. The position where the force receiving portion 53 of the main strut 41 is formed is located radially outside the innermost surface radially inside the inner convex portion 49.

[0042] The distal-side connecting strut 46 is located at the distal end of the main strut 41. A plurality of distal-side connecting struts 46 are connected in an annular arrangement in the circumferential direction. Each distal-side connecting strut 46 has a substantially rhombic distal through-hole 55 formed therethrough in the radial direction of the expander 40 and is formed in a substantially rhombic frame shape. That is, each distal-side connecting strut 46 is formed with a lattice structure that can be changed into a quadrilateral with the same side lengths but different angles. The plurality of distal-side connecting struts 46 are joined at opposite rhombic points and connected in an annular arrangement in the circumferential direction. For this reason, the plurality of distal-side connecting struts 46 arranged in an annular shape are connected so as to be expandable and contractible in the radial direction by utilizing the lattice structure. For this reason, the position of the force-receiving portion 53 that slidably holds the aforementioned traction shaft 60 is movable in the radial direction.

[0043] Each secondary strut 56 is disposed between two circumferentially adjacent main struts 41 and is connected to the two main struts 41. Each secondary strut 56 has a proximal-side support strut 59 (support strut) connected to two circumferentially adjacent outer edge portions 51, a distal-side support strut 57 (support strut) connected to the distal ends of two circumferentially adjacent distal-side main struts 45, and a confluence strut 58 provided between the proximal-side support strut 59 and the distal-side support strut 57.

[0044] Each tip-side support strut 57 has two tip-side inclined struts 57A and a confluence part that connects the two tip-side inclined struts 57A. The two tip-side inclined struts 57A extend from the joint J1 with the tip of the main strut 41 toward the base end in a manner inclined with respect to the axis of the expandable body 40 as viewed from the radially outer side, and are connected to the tip of the confluence strut 58. The two tip-side inclined struts 57A connected to the same confluence strut 58 have a shape that is symmetric with respect to the plane passing through the confluence part of the two tip-side inclined struts 57A and the axis of the expandable body 40. In the deployed configuration, each tip-side support strut 57 is formed to be longer than the straight-line distance between the joints J1 with the two connected main struts 41 as viewed from the radially outer side. For this reason, when the expandable body 40 assumes an expanded configuration in which it expands radially more than in the deployed configuration, each tip-side support strut 57 can be deformed so as to approach a straight shape so that the two joints J1 move apart.

[0045] Each base-end-side support strut 59 has two base-end-side inclined struts 59A. The two base-end-side inclined struts 59A extend from the joint J2 with the outer edge 51 of the main strut 41 toward the tip in a manner inclined with respect to the axis of the expandable body 40 as viewed from the radially outer side, and are connected to the base end of the confluence strut 58. The two base-end-side inclined struts 59A connected to the same confluence strut 58 have a shape that is symmetric with respect to the plane passing through the confluence part of the two base-end-side inclined struts 59A and the axis of the expandable body 40. In the deployed configuration, each base-end-side support strut 59 is formed to be longer than the straight-line distance between the joints J2 with the two connected main struts 41 as viewed from the radially outer side. For this reason, when the expandable body 40 assumes an expanded configuration in which it expands radially more than in the deployed configuration, each base-end-side support strut 59 can be deformed so as to approach a straight shape so that the two joints J2 move apart.

[0046] The confluence struts 58 are evenly arranged circumferentially around the axis of the expandable body 40. Each confluence strut 58 extends substantially parallel to the axis of the expandable body 40 as viewed from the radially outer side between the tip-side support strut 57 and the base-side support strut 59. The sub-strut 56 has a sub-strut outward convex portion 56A formed on the base-side support strut 59 or the confluence strut 58 and protruding radially outward.

[0047] In a cross-section perpendicular to the axis at any axial position of the portion where the sub-strut 56 is present, the outermost position in the radial direction of the main strut 41 of the expandable body 40 in the natural state is located radially outside the outermost position in the radial direction of the sub-strut 56. Further, in a cross-section perpendicular to the axis at the position where the tip-side outward convex portion 48 of the expandable body 40 in the natural state is provided, the tip-side outward convex portion 48 of the main strut 41 is located radially outside the outermost position in the radial direction of the sub-strut 56.

[0048] When the traction shaft 60 moves toward the base end side, as shown in FIG. 6, the sliding shaft 70 slides along the force receiving portion 53, and the engaging portion 71 engages with the force receiving portion 53. The engaging portion 71 engaged with the force receiving portion 53 can apply a traction force toward the base end direction to the force receiving portion 53. Thereby, the expandable body 40 can be compressed in the axial direction and become an expanded form that is expanded in the radial direction compared to the deployed form. When the expandable body 40 is in the expanded form, the base-side clamping strut 43 and the tip-side clamping strut 44 approach each other.

[0049] The main strut 41 and the sub-strut 56 constituting the expandable body 40 are integrally formed, for example, by laser processing a cylinder. The main strut 41 and the sub-strut 56 can have a thickness of 50 to 500 μm and a width of 0.1 to 2.0 mm. However, the main strut 41 and the sub-strut 56 may have dimensions outside this range. Also, the shapes of the main strut 41 and the sub-strut 56 are not limited, and they may have, for example, a circular cross-sectional shape or other cross-sectional shapes.

[0050] The expandable body 40 that expands in a natural state is shaped using, for example, the jig 200 shown in FIG. 18. The jig has a first jig 201 disposed inside the tip side of the expandable body 40 and a second jig 202 disposed inside the base end side of the expandable body 40. The first jig 201 has a substantially conical shape, and at a portion where the outer diameter expands, a large diameter portion 203 with a large outer diameter and a small diameter portion 204 with a small outer diameter are arranged alternately. The first jig 201 has, at its base end portion, a first inclined surface 205 where the outer diameter of the first jig 201 decreases as it goes toward the base end. The second jig 202 has a substantially conical shape. The second jig 202 has, at its tip portion, a second inclined surface 206 where the outer diameter of the second jig 202 decreases as it goes toward the tip. When the first jig 201 is disposed inside the tip side portion of the expandable body 40, as shown in FIG. 19(A), the auxiliary strut 56 is disposed outside the small diameter portion 204, and the main strut 41 is disposed outside the large diameter portion 203. Note that the second jig 202 can be disposed inside the base end side portion of the expandable body 40 without limiting its circumferential position. The base end portion of the first jig 201 is disposed away from the tip portion of the second jig 202. Thereafter, as shown in FIG. 19(B), while bringing the base end portion of the first jig 201 into contact with the tip portion of the second jig 202, the main strut 41 and the auxiliary strut 56 are arranged along the first jig 201 and the second jig 202. When the base end portion of the first jig 201 is brought into contact with the tip portion of the second jig 202, a constricted portion 207 constricted inward can be formed from the first inclined surface 205 and the second inclined surface 206. The plurality of main struts 41 and the plurality of auxiliary struts 56 can be pressed against the constricted portion 207 and deformed into a shape along the constricted portion 207. That is, the main strut 41 is deformed into a shape along the large diameter portion 203 and the constricted portion 207, and the auxiliary strut 56 is deformed into a shape along the small diameter portion 204 and the constricted portion 207. Thereafter, if necessary, a heat treatment may be performed to maintain the shape of the deformed expandable body 40. Thereby, the expandable body 40 can be formed into an expandable body 40 having the main strut 41 that protrudes radially outside the auxiliary strut 56 and the auxiliary strut 56.When the extension body 40 is formed from a pipe made of a material having spring properties such as a nickel-titanium alloy, etc., the elastic force with which the extension body 40 tries to return to its original pipe shape causes it to cling to the jig, and as a result, the main strut 41 deforms along the large-diameter portion 203, and the sub-strut 56 deforms along the small-diameter portion 204. When deforming the main strut 41 and the sub-strut 56, the main strut 41 may be pressed against the large-diameter portion 203 and the sub-strut 56 may be pressed against the small-diameter portion 204. Thereby, the main strut 41 and the sub-strut 56 can be more surely deformed into a predetermined shape.

[0051] As shown in FIGS. 2 and 9, the energy transmission element 90 is disposed opposite to the abutting portion 52 of the tip-side clamping strut 44 on the base-end-side clamping strut 43. For this reason, when the base-end-side clamping strut 43 and the tip-side clamping strut 44 clamp the atrial septum HA, the energy from the energy transmission element 90 is transmitted to the atrial septum HA from the right atrium side. Note that the energy transmission element 90 may be disposed on the tip-side clamping strut 44, and the abutting portion 52 may be disposed on the base-end-side clamping strut 43. In this case, the energy from the energy transmission element 90 is transmitted to the atrial septum HA from the left atrium side.

[0052] The energy transmission element 90 is constituted by, for example, a bipolar electrode that receives electrical energy from an energy supply device (not shown), which is an external device. In this case, energization is performed between the energy transmission elements 90 disposed on each main strut 41. The energy transmission element 90 and the energy supply device are connected by a conducting wire (not shown) coated with an insulating coating material. The conducting wire is led out to the outside through the shaft portion 20 and the operation portion 80 and connected to the energy supply device.

[0053] The energy transmission element 90 may also be configured as a monopolar electrode. In this case, energization is performed with a counter electrode plate prepared outside the body. Further, the energy transmission element 90 may be a heating element (electrode chip) that receives and emits high-frequency electrical energy from an energy supply device to generate heat. In this case, energization is performed between the energy transmission elements 90 arranged on each main strut 41. Furthermore, the energy transmission element 90 can be constituted by an element capable of imparting energy to the through hole Hh, such as microwave energy, ultrasonic energy, coherent light such as a laser, a heated fluid, a cooled fluid, a chemical medium that exerts a heating or cooling action, a device that generates frictional heat, a heater provided with an electric wire, etc., and the specific form is not particularly limited.

[0054] As shown in FIG. 1, the operation unit 80 has a housing 81 that is gripped by the operator and a moving unit 82 that can be operated by the operator. The moving unit 82 is fixed to the traction shaft 60 inside the operation unit 80. The moving unit 82 is movable forward and backward with respect to the housing 81 in the axial direction of the traction shaft 60. Therefore, the operator can move the traction shaft 60 in the axial direction by moving the moving unit 82.

[0055] The expandable body 40 can be formed of a metal material. As this metal material, for example, alloys of the titanium series (Ti-Ni, Ti-Pd, Ti-Nb-Sn, etc.), alloys of the copper series, stainless steel, β-titanium steel, Co-Cr alloy can be used. It is preferable to use an alloy having spring properties such as a nickel-titanium alloy. However, the material of the expandable body 40 is not limited to these, and it may be formed of other materials.

[0056] The storage sheath 30 and the outer tube 20 are preferably formed of a material having a certain degree of flexibility. Examples of such materials include polyolefins such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more of these, soft polyvinyl chloride resin, polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane, fluororesin such as polytetrafluoroethylene, polyimide, PEEK, silicone rubber, latex rubber, and the like.

[0057] The traction tube 61 can be formed, for example, by coiling a long wire or plate material such as a superelastic alloy such as a nickel-titanium alloy or a copper-zinc alloy, or a metal material such as stainless steel, a slotted pipe made of these metal materials, or a tube body of a resin material having relatively high rigidity. Further, the traction tube 61 may have an outer coating layer coated with a resin material such as polyvinyl chloride, polyethylene, polypropylene, ethylene-propylene copolymer, or fluororesin on its outer peripheral surface. Thereby, it becomes easier for the traction tube 61 to move forward and backward in the axial direction inside the outer tube 20. Further, the traction tube 61 may have an inner coating layer coated with the above resin material (particularly fluororesin) on its inner peripheral surface. Thereby, it becomes easier to insert the guide wire 11 and the balloon catheter 12 into the traction tube 61.

[0058] The expansion part 62 can be formed, for example, of a superelastic alloy such as a nickel-titanium alloy or a copper-zinc alloy, a metal material such as stainless steel, or a resin material having relatively high rigidity.

[0059] Next, a treatment method using the medical device 10 according to the present embodiment will be described. This treatment method is performed on a patient suffering from heart failure (left heart failure). More specifically, as shown in FIG. 7, it is a treatment method performed on a patient suffering from chronic heart failure in which the myocardium of the left ventricle of the heart H hypertrophies and the stiffness (hardness) increases, thereby increasing the blood pressure in the left atrium HLa.

[0060] When forming the through-hole Hh, the operator delivers an introducer combined with a guiding sheath and a dilator to the vicinity of the atrial septum HA. The introducer can be delivered to the right atrium HRa, for example, via the inferior vena cava Iv. Also, the delivery of the introducer can be performed using the guide wire 11. The operator can insert the guide wire 11 through the dilator and deliver the introducer along the guide wire 11. Note that the insertion of the introducer into the living body, the insertion of the guide wire 11, etc. can be performed by known methods such as using an introducer for vascular introduction.

[0061] Next, the operator penetrates a puncture device (not shown) and a dilator from the right atrium HRa side toward the left atrium HLa side to form the through-hole Hh. As the puncture device, for example, a device such as a wire with a sharp tip can be used. The puncture device is inserted through the dilator and delivered to the atrial septum HA. After removing the guide wire 11 from the dilator, the puncture device can be delivered to the atrial septum HA instead of the guide wire 11.

[0062] Next, the operator delivers the medical device 10 to the vicinity of the atrial septum HA along the guide wire 11 that has been previously inserted from the right atrium HRa through the through-hole Hh into the left atrium HLa. Then, a part of the tip of the medical device 10 passes through the through-hole Hh opened in the atrial septum HA and reaches the left atrium HLa. When inserting the medical device 10, the expander 40 is in a contracted form housed in the housing sheath 30 as shown in FIG. 8. In the contracted form, the expander 40 and the spreading portion 62 that protrude radially outward in the natural state (deployed form) are deformed to contract radially and are housed in the housing sheath 30. When housing the expander 40 in the housing sheath 30, the engaging portion 71 of the traction shaft 60 is arranged farther from the tip side than the force-receiving portion 53 of the expander 40. Thereby, when the expander 40 contracts radially and extends in the axial direction, the force-receiving portion 53 of the expander 40 slides along the sliding shaft 70 of the traction shaft 60 and does not contact the engaging portion 71. For this reason, the deformation of the expander 40 is not hindered by the traction shaft 60.

[0063] Next, as shown in FIG. 9, by moving the storage sheath 30 toward the proximal end side, the distal end side portion of the expander 40 is exposed into the left atrium HLa. As a result, the distal end side portion of the expander 40 expands radially within the left atrium HLa by its own restoring force. Since the main strut 41 on the distal end side of the expander 40 rather than the inner convex portion 49 is supported by the sub-strut 56, it is difficult to twist in the circumferential direction. For this reason, the distal end side portion of the expander 40 that is first released from the storage sheath 30 can be deployed in an appropriate shape. Next, by moving the storage sheath 30 toward the proximal end side, the entire expander 40 is exposed. As a result, the proximal end side portion of the expander 40 expands radially within the right atrium HRa by its own restoring force. Since the distal end side portion of the expander 40 that has been deployed first has an appropriate shape due to the provision of the sub-strut 56, the proximal end side portion of the expander 40 that is later deployed can also be supported by the distal end side portion and can have an appropriate shape. When the entire expander 40 is deployed, the inner convex portion 49 is disposed inside the through hole Hh. As a result, the entire expander 40 expands by its own restoring force and restores to the original deployed form or a form close to the deployed form. At this time, the atrial septum HA is disposed between the proximal end side clamping strut 43 and the distal end side clamping strut 44. In the clamping direction of the biological tissue, the atrial septum HA is disposed between the energy transmission element 90 and the abutting portion 52.

[0064] Next, the operator inserts the balloon catheter 12 into the lumen from the proximal end side of the traction tube 61. The balloon catheter 12 has a balloon 13 (auxiliary expander) that expands when supplied with fluid at the tip of a long tubular body. The operator causes the balloon 13 to reach within the range where the expander 40 is provided in the axial direction. The balloon 13 is disposed inside the inner convex portion 49 of the expander 40, that is, inside the through-hole Hh. The tip-side connecting strut 46 located at the tip of the expander 40 expands radially by changing from the contracted form to the deployed form. For this reason, the balloon 13 can be disposed inside the tip of the expander 40. Further, the widened portion 62 of the traction shaft 60 is disposed radially outside the inner diameter of the outer tube 20. Furthermore, the widened portion 62 is expandable radially outward. For this reason, the widened portion 62 does not contact the balloon 13 inserted inside the expander 40, or even if it contacts, it can deform so as to escape radially outward. For this reason, the traction shaft 60 does not prevent the balloon 13 from being disposed inside the expander 40.

[0065] Next, as shown in FIG. 10, the operator supplies expansion fluid to the balloon catheter 12 from the proximal end side to expand the balloon 13. At this time, the tip-side connecting strut 46 located at the tip of the expander 40 expands radially by changing from the contracted form to the deployed form. And the widened portion 62 of the traction shaft 60 does not contact the balloon 13 inserted inside the expander 40, or even if it contacts, it can deform so as to move radially outward. Thereby, the expander 40 and the traction shaft 60 do not prevent the expansion of the balloon 13 inside the expander 40. The expanded balloon 13 expands the through-hole Hh together with the inner convex portion 49 passing through the through-hole Hh.

[0066] In addition, the traction shaft 60 can move in the axial direction without being obstructed by the inflated balloon 13. The inner convex portion 49 of the expansion body 40 is arranged to face the hexagonal gap of the link portion 65 so that the traction shaft 60 can move in the state where the balloon 13 is inflated. Thereby, when the traction shaft 60 moves, it is possible to suppress the inner convex portion 49 of the expansion body 40 from contacting the traction shaft 60 and preventing the movement. For this reason, the operator can move the traction shaft 60 in the proximal direction in the state where the balloon 13 is inflated to expand the expansion body 40. The operator operates the operation unit 80 to move the traction shaft 60 to the proximal side. As a result, as shown in FIG. 11, the sliding shaft 70 slides along the force receiving portion 53, and the engaging portion 71 engages with the force receiving portion 53. The engaging portion 71 engaged with the force receiving portion 53 applies a traction force toward the proximal direction to the force receiving portion 53. Thereby, the expansion body 40 contracts in the axial direction and becomes an expanded form that expands in the radial direction more than the deployed form. When the expansion body 40 becomes the expanded form, the proximal side clamping strut 43 and the distal side clamping strut 44 approach each other, and the atrial septum HA is clamped between the proximal side clamping strut 43 and the distal side clamping strut 44. At this time, the energy transmission element 90 and the abutting portion 52 face each other. With the proximal side clamping strut 43 and the distal side clamping strut 44 clamping the atrial septum HA, the traction shaft 60 is further pulled. As a result, the proximal side clamping strut 43 and the distal side clamping strut 44 can be further expanded, and the through hole Hh can be further expanded in the radial direction. That is, the operator can expand the through hole Hh in the radial direction by interlocking the expansion by the expansion body 40 and the expansion by the balloon 13. Therefore, even when the through hole Hh, which is the tissue to be expanded, is hard, the expansion body 40 and the balloon 13 can expand the through hole Hh to a desired size. Note that it is not necessary to further pull the traction shaft 60 after the proximal side clamping strut 43 and the distal side clamping strut 44 clamp the atrial septum HA.

[0067] The main strut 41 receiving the traction force from the traction shaft 60 clamps the atrial septum HA. At this time, the main strut 41 is supported by the proximal side support strut 59 and the distal side support strut 57 adjacent in the circumferential direction.

[0068] Each distal end side support strut 57 is formed to be longer than the straight-line distance between the two joint points J1 when viewed from the radially outer side in the unfolded form before expansion. For this reason, when the expandable body 40 assumes the expanded form, each distal end side support strut 57 can be easily deformed so that the two joints J1 move apart. Therefore, the distal end side support strut 57 can support the main strut 41 without applying an excessive tensile force to the main strut 41.

[0069] Also, each proximal end side support strut 59 is formed to be longer than the straight-line distance between the two joint points J2 when viewed from the radially outer side in the unfolded form before expansion. For this reason, when the expandable body 40 assumes the expanded form, each proximal end side support strut 59 can be easily deformed so that the two joints J2 move apart. Therefore, the proximal end side support strut 59 can support the main strut 41 without applying an excessive tensile force to the main strut 41.

[0070] For this reason, the main strut 41 is suppressed from twisting in the circumferential direction. Further, since the sub-strut 56 is located radially inward of the main strut 41, when expanding, it is possible to suppress the main strut 41, which was linear, from being pulled and bent by the sub-strut 56. For this reason, the force with which the main strut 41 presses the energy transmission element 90 against the tissue is less likely to be dispersed, and the energy transmission element 90 can be effectively pressed against the tissue.

[0071] Here, after the balloon 13 is expanded, the expandable body 40 is used for clamping. However, after the expandable body 40 is used for clamping, the balloon 13 may be expanded.

[0072] When the atrial septum HA is sandwiched between the proximal-side clamping strut 43 and the distal-side clamping strut 44, the energy transmission element 90 presses the atrial septum HA toward the distal side. At this time, the distal-side clamping strut 44 deflects the abutting portion 52 toward the distal side between the two outer edge portions 51, and receives the atrial septum HA pressed by the energy transmission element 90 between the two outer edge portions 51. The two outer edge portions 51 effectively guide the energy transmission element 90 to the abutting portion 52 located between the outer edge portions 51. The abutting portion 52 receives force from the energy transmission element 90 through the atrial septum HA and deflects so as to be substantially parallel to the energy transmission element 90. Then, while the abutting portion 52 deflects flexibly, a repulsive force in the direction opposite to the pushing direction of the energy transmission element 90 acts on the atrial septum HA pushed by the energy transmission element 90. Thereby, the energy transmission element 90 adheres to the atrial septum HA.

[0073] After the operator expands the through-hole Hh, the operator can check the hemodynamics by contracting the balloon 13. The operator delivers the hemodynamic confirmation device 100 to the right atrium HRa via the inferior vena cava Iv. As the hemodynamic confirmation device 100, for example, a known echo catheter can be used. The operator can display the echo image obtained by the hemodynamic confirmation device 100 on a display device such as a display, and check the blood volume passing through the through-hole Hh based on the display result.

[0074] Next, the operator performs a maintenance treatment to maintain the size of the through-hole Hh. In the maintenance treatment, energy is applied to the edge of the through-hole Hh through the energy transmission element 90, and the edge of the through-hole Hh is cauterized (heated cauterization) by the energy. When the biological tissue near the edge of the through-hole Hh is cauterized through the energy transmission element 90, a modified portion where the biological tissue is modified is formed near the edge. Since the biological tissue in the modified portion loses its elasticity, the through-hole Hh can maintain the shape when it is expanded by the expander 40 and the balloon 13.

[0075] After the maintenance treatment, the operator discharges the fluid for expansion from the balloon 13 to contract the balloon 13, and then checks the hemodynamics again. When the amount of blood passing through the through-hole Hh is the desired amount, the operator removes the balloon catheter 12 from the medical device 10. Next, the operator reduces the diameter of the expander 40, stores it in the storage sheath 30, and then removes it from the through-hole Hh. Further, the operator removes the entire medical device 10 from the living body to end the treatment.

[0076] As described above, the medical device 10 according to the present embodiment includes a long outer tube 20, an expander 40 connected to the tip of the outer tube 20 and expandable in the radial direction by contracting along the axis of the outer tube 20, and disposed inside the outer tube 20 and protruding from the tip of the outer tube 20 and connected to the tip of the expander 40, and a traction shaft 60 slidable with respect to the outer tube 20. The expander 40 has a plurality of main struts 41 arranged at intervals in the circumferential direction and extending a predetermined length along the axis of the outer tube 20, and a plurality of sub-struts 56 connected to the plurality of main struts 41. Each of the plurality of main struts 41 is substantially parallel to the axis when viewed from the outside in the radial direction, and each of the plurality of sub-struts 56 has at least two joints joined to each of two adjacent main struts 41 in the circumferential direction among the plurality of main struts 41. At least two of the joints are arranged at different positions in the axial direction of the outer tube 40. In a cross-section perpendicular to the axis of the expander 40 at any position where the sub-strut 56 exists, the outermost position in the radial direction of the main strut 41 in the natural state is located outside the outermost position in the radial direction of the sub-strut 56.

[0077] The medical device 10 configured as described above can suppress the circumferential twist of the main strut 41 that expands radially and acts on the tissue by receiving a traction force, by means of the secondary strut 56. Note that the secondary strut 56 is likely to be shorter in the axial direction than the main strut 41 in order to change the inclination angle when the circumferential distance between the two main struts 41 to which the secondary strut 56 is connected increases. However, in a cross-section perpendicular to the axis, since the outermost position in the radial direction of the main strut 41 is located outside the outermost position in the radial direction of the secondary strut 56, it is possible to suppress the secondary strut 56 from becoming shorter in the axial direction than the main strut 41 and reduce the influence on the main strut 41. That is, the secondary strut 56 located on the inner side in the radial direction can connect the two main struts 41 arranged in the circumferential direction at a shorter distance than when it is located on the outer side in the radial direction. For this reason, it is possible to suppress the main strut 41, to which the secondary strut 56 is connected at a plurality of positions in the axial direction, from being excessively deflected by receiving a tensile force from the secondary strut 56 when the expander 40 expands. For this reason, in the medical device 10, the force pressing the expander 40 against the tissue is less likely to be dispersed, and it is possible to effectively transmit the force to the living tissue by the expander 40.

[0078] Further, the plurality of sub-struts 56 extend from each of two circumferentially adjacent main struts 41, and include two tip-side inclined struts 57A and two base-side inclined struts 59A that are inclined with respect to the axis when viewed from the outer side in the radial direction, and a confluence strut 58 (confluence portion) to which the two tip-side inclined struts 57A and the two base-side inclined struts 59A are connected. The two tip-side inclined struts 57A and the two base-side inclined struts 59A connected to the confluence strut 58 are plane-symmetric with respect to a plane passing through the axis of the confluence strut 58 and the expander 40. Thereby, when the expander 40 deforms, the two tip-side inclined struts 57A and the two base-side inclined struts 59A that are plane-symmetric deform into symmetric shapes. For this reason, the forces acting on the two circumferentially adjacent main struts 41 from the tip-side inclined struts 57A and the base-side inclined struts 59A become equal. Therefore, it is possible to suppress the occurrence of torsional strain in the circumferential direction in the main strut 41. Note that even if the inclined strut has a curved shape, since the tangent line at any part is inclined with respect to the axis, it can be regarded as an inclined strut.

[0079] Also, two of the inclined struts provided on each sub-strut 56 are tip-side inclined struts 57A that are arranged side by side in the circumferential direction between two circumferentially adjacent main struts 41 and are connected to the main struts 41. The two inclined struts provided on each sub-strut 56 are located on the base side with respect to the tip-side inclined struts 57A, and are base-side inclined struts 59A that are arranged side by side in the circumferential direction between two circumferentially adjacent main struts 41 and are connected to the main struts 41. Each sub-strut 56 has a confluence strut 58 (confluence portion) that connects the tip-side inclined strut 57A and the base-side inclined strut 59A. Thereby, it is possible to effectively suppress the main struts 41 to which the sub-struts 56 are connected at a plurality of positions in the axial direction from being overly deflected. For this reason, in the medical device 10, the force for pressing the expander 40 against the tissue is less likely to be dispersed, and the expander 40 can be effectively pressed against the tissue.

[0080] In addition, the main strut 41 has a distal-side convex portion 48 (convex portion) that protrudes radially outward, and the auxiliary strut 56 is connected to the main strut 41 on the distal side and the proximal side of the distal-side convex portion 48. In a cross-section perpendicular to the axis at the position where the distal-side convex portion 48 is provided, the position of the distal-side convex portion 48 in the natural state is located outside the most radially outer position of the auxiliary strut 56. Thereby, when the expander 40 expands, while protruding the distal-side convex portion 48 of the main strut 41, it is possible to effectively suppress the excessive bending of the portions other than the distal-side convex portion 48 of the main strut 41 due to the tensile force received from the auxiliary strut 56. For this reason, in the medical device 10, the force for pressing the expander 40 against the tissue is less likely to be dispersed, and the expander 40 can be effectively pressed against the tissue.

[0081] In addition, the main strut 41 has a distal-side clamping strut 44 and a proximal-side clamping strut 43 whose separation distance decreases as the expander 40 expands, and an inner convex portion 49 that protrudes radially inward is formed between the distal-side clamping strut 44 and the proximal-side clamping strut 43. The auxiliary strut 56 is disposed on at least one of the distal side or the proximal side of the inner convex portion 49. Thereby, it is possible to effectively suppress the excessive bending of the portions on the distal side and the proximal side of the inner convex portion 49 due to the tensile force received from the auxiliary strut 56. For this reason, in the medical device 10, the force for gripping the tissue by the distal-side clamping strut 44 and the proximal-side clamping strut 43 is less likely to be dispersed, and the tissue can be effectively gripped.

[0082] In addition, the medical device 10 has an energy transmission element 90 that is disposed on the expander 40 and outputs energy. Thereby, the medical device 10 can perform cauterization by the energy transmission element 90 in a state where the lumen or hole of the living body is expanded to a desired size by the expander 40 whose excessive bending is suppressed.

[0083] Moreover, the manufacturing method of the expander 40 in the present embodiment is a manufacturing method of the expander 40 having a tip portion and a base end portion, including a plurality of main struts 41 arranged at intervals in the circumferential direction and extending a predetermined length along the axis passing through the tip portion and the base end portion, and a plurality of sub-struts 56 connected to the plurality of main struts 41. Prepare an expander 40. Place a jig 200 inside the expander 40, in which a plurality of small-diameter portions 204 and a plurality of large-diameter portions 203 having an outer diameter larger than that of the small-diameter portions 204 are alternately arranged in the circumferential direction. Arrange the plurality of main struts 41 outside the radial direction of the plurality of large-diameter portions 203 to deform the plurality of main struts 41 into a shape along the plurality of large-diameter portions 203, and arrange the plurality of sub-struts 56 outside the radial direction of the plurality of small-diameter portions 204 to deform the sub-struts 56 into a shape along the plurality of small-diameter portions 204. Thereby, the manufacturing method of the expander 40 can manufacture an expander 40 in which the outermost position in the radial direction of the main strut 41 in the natural state is arranged outside the outermost position in the radial direction of the sub-strut 56.

[0084] Also, when deforming the plurality of main struts 41 and the plurality of sub-struts 56, the plurality of main struts 41 may be pressed against the plurality of large-diameter portions 203, and the plurality of sub-struts 56 may be pressed against the plurality of small-diameter portions 204, respectively. Thereby, the plurality of main struts 41 and the plurality of sub-struts 56 can be easily made into a desired shape by the large-diameter portions 203 and the small-diameter portions 204.

[0085] Further, the jig 200 includes a first jig 201 disposed inside the tip side of the extension body 40 and a second jig 202 disposed inside the base end side of the extension body 40. At least one of the first jig 201 and the second jig 202 has a plurality of small-diameter portions 204 and a plurality of large-diameter portions 203. The first jig 201 has a first inclined surface 205 at its base end portion, and the outer diameter of the first jig 201 decreases as it approaches the base end. The second jig 202 has a second inclined surface 206 at its tip end portion, and the outer diameter of the second jig 202 decreases as it approaches the tip end. When the jig 200 is disposed inside the extension body 40, a constricted portion 207 constricted inward is formed by the first inclined surface 205 and the second inclined surface 206, and the plurality of main struts 41 and the plurality of sub-struts 56 may be pressed against the constricted portion 207 to deform them into a shape along the constricted portion 207. Thereby, it becomes easy to form an inward convex portion 49 protruding radially inward on the main strut 41.

[0086] The first jig 201 and the second jig 202 are spaced apart when the jig 200 is disposed inside the extension body 40, and may contact each other when deforming the plurality of main struts 41 and the plurality of sub-struts 56 into a shape along the constricted portion 207. Thereby, it becomes easy to set the first jig 201 and the second jig 202 in an accurate relative positional relationship. For this reason, the extension body 40 can be easily formed into a desired shape.

[0087] Note that the present invention is not limited to the above-described embodiments, and various modifications can be made by those skilled in the art within the technical idea of the present invention. For example, the tip-side support strut 57 and the base-end-side support strut 59 may be directly connected without being connected by the long joining shaft 58. In this case, the connection portion is the joining portion.

[0088] Also, as in the first modification shown in FIG. 12, sub-struts 56 provided with inclined struts may be provided on both the tip side and the base end side of the inward convex portion 49. Alternatively, the sub-struts 56 may be provided only on the base end side of the inward convex portion 49.

[0089] Further, as in the second modification example shown in FIG. 13, two inclined struts 110 may be formed on an arc-shaped auxiliary strut 56 connected to two main struts 41 adjacent in the circumferential direction. The position where the arc-shaped auxiliary strut 56 is connected to the main strut 41 is not limited to the tip-side main strut 45, and may be, for example, the tip-side clamping strut 44, the base-side clamping strut 43, or the base-side main strut 42, etc.

[0090] Further, as in the third modification example shown in FIG. 14, the traction shaft 60 may have an inner tube 75 that can move axially inside the outer tube 20, and an engaging portion 71 to which the tip of the inner tube 75 is fixed. The engaging portion 71 is pulled in the base end direction by the inner tube 75, and the expandable body 40 can be compressed axially. And the expandable body 40 has a tubular force-receiving portion 53 to which a plurality of main struts 41 are connected at the tip. The engaging portion 71 may be ring-shaped with an opening so that the guide wire 11 can be inserted, or may have a shape without an opening. The main struts 41 of the expandable body 40 may be pulled by the traction shaft 60 and bent radially outward and expanded without the tip-side clamping strut 44 and the base-side clamping strut 43 being provided. Although the energy transmission element 90 is arranged on the main strut 41, it may not be arranged.

[0091] Further, as in the fourth modification example shown in FIG. 15, the tip-side inclined strut 57A of the auxiliary strut 56 may be connected to the tip of the main strut 41, and the base-side inclined strut 59A may be connected to the base of the main strut 41.

[0092] Further, as in the fifth modification example shown in FIG. 16, two tip-side inclined struts 57A of the auxiliary strut 56 may be provided, and only one base-side inclined strut 59A may be provided. Also, only one tip-side inclined strut 57A may be provided, and two base-side inclined struts 59A may be provided.

[0093] Further, as in the sixth modification shown in FIG. 17, the expansion body 40 may have a tubular force-receiving portion 53 to which a plurality of main struts 41 are connected at its tip, and each main strut 41 may have an inward protrusion 49. The traction shaft 60 has an inner tube 75 movable in the axial direction inside the outer tube 20 and an engaging portion 71 fixed to the tip of the inner tube 75. The engaging portion 71 is pulled in the proximal direction by the inner tube 75 so that the expansion body 40 can be compressed in the axial direction. Each main strut 41 has a proximal main strut 42, a proximal clamping strut 43, a distal clamping strut 44, and a distal main strut 45 from the proximal side to the distal side.

[0094] The proximal main strut 42 is inclined so as to increase radially from the tip of the outer tube 20 in the distal direction, and the distal main strut 45 is inclined so as to increase radially from the tubular force-receiving portion 53 in the proximal direction. The proximal clamping strut 43 is inclined so as to decrease radially from the tip of the proximal main strut 42 in the distal direction, and the distal clamping strut 44 is inclined so as to decrease radially from the base of the distal main strut 45 in the proximal direction. The proximal clamping strut 43 and the distal clamping strut 44 are connected by an inward protrusion 49 protruding inward in the radial direction. An energy transmission element 90 is disposed at a position where the proximal clamping strut 43 or the distal clamping strut 44 of the main strut 41 faces to sandwich the biological tissue.

[0095] The expansion body has a sub-strut 56 on the distal side of the inward protrusion 49 and a proximal sub-strut 56B on the proximal side of the inward protrusion 49. The distal support strut 57 at the tip of the sub-strut 56 is connected to each of the two adjacent distal main struts 45 in the circumferential direction, and the proximal support strut 59 at the base of the sub-strut 56 is connected to each of the two adjacent distal clamping struts 44 in the circumferential direction.

[0096] The proximal-side secondary strut 56B is connected to each of two adjacent proximal-side main struts 42 in the circumferential direction. The proximal-side secondary strut 56B has two inclined struts 56C that are inclined with respect to the axis when viewed from the outer side in the radial direction. The two inclined struts 56C extend in the proximal direction while approaching each adjacent proximal-side main strut 42 in the circumferential direction and are connected at a confluence portion 56D. The two inclined struts 56C connected to the confluence portion 56D are plane-symmetric with respect to a plane passing through the axis of the confluence portion 56D and the expandable body 40. In the eighth modification, since the medical device 10 has the secondary strut 56 and the proximal-side secondary strut 56B at positions separated in the axial direction of the expandable body 40, when the energy transmission element 90 is pressed against the tissue, the torsional movement of the main strut 41 in the circumferential direction can be effectively suppressed.

[0097] Also, as in the seventh modification shown in FIG. 18, the proximal wire 64 and the intermediate link portion 68 of the widening portion 62 may be arranged linearly. The proximal link portion 66 connects the connection portions of the proximal wire 64 and the intermediate link portion 68 and protrudes in the distal direction. In this case, when the widening portion 62 is slid in the proximal direction with respect to another member, the proximal link portion 66 is not caught by the other member. By the way, in the case of the widening portion 62 in the embodiment shown in FIG. 4, when the balloon 13 having a large expansion dimension is used, the axial length of the widening portion 62 tends to be short, and when the balloon 13 having a small expansion dimension is used, the axial length of the widening portion 62 tends to be long. Therefore, it is necessary to adjust the traction amount of the traction shaft 60 according to the deviation. On the other hand, in the seventh modification, the change in the axial length of the widening portion 62 caused by expansion and contraction is small. For this reason, the variation in the traction amount of the traction shaft 60 due to the expansion dimension of the balloon 13 is suppressed.

[0098] Note that this application is based on Japanese Patent Application No. 2020-58893 filed on March 27, 2020, the disclosures of which are incorporated herein by reference in their entirety.

Explanation of Reference Numerals

[0099] 10 Medical device 11 Guide wire 12 Balloon catheter 13 Balloon (auxiliary expansion body) 20 Outer tube 30 Storage sheath 40 Expansion body 41 Main strut 42 Proximal main strut 43 Proximal clamping strut 44 Distal clamping strut 45 Distal main strut 46 Distal connecting strut 47 Proximal protrusion (protrusion) 48 Distal protrusion (protrusion) 49 Inner protrusion 50 Intermediate through-hole 51 Outer edge 52 Backrest 53 Force-receiving part 55 Distal through-hole 56 Sub-strut 56B Proximal sub-strut (sub-strut) 56C Inclined strut 56D Confluence part 57 Distal support strut (support strut) 57A Distal inclined strut (inclined strut) 58 Confluence strut (confluence part) 59 Proximal support strut (support strut) 59A Proximal inclined strut (inclined strut) 60 Traction shaft 61 Traction tube 62 Expansion part 63 Proximal connection part 64 Proximal wire 65 Link part 66 Proximal link part 67 Distal link part 68 Intermediate link part 69 Sub-wire 70 Sliding shaft 71 Engagement part 72 Traction wire 75 Inner tube 80 Operation unit 81 Housing 82 Moving part 90 Energy transmission element 200 Fixture 201 First fixture 202 Second fixture 203 Large-diameter part 204 Small-diameter part 205 First inclined surface 206 Second inclined surface 207 Constricted part

Claims

1. A long outer tube, An expansion body connected to the tip of the outer tube and expandable in the radial direction by contracting along the axis of the outer tube, A traction shaft disposed inside the outer tube, protruding from the tip of the outer tube and connected to the tip of the expansion body, and slidable with respect to the outer tube, The expansion body has a plurality of main struts arranged at intervals in the circumferential direction and extending a predetermined length along the axis of the outer tube, and a plurality of sub-struts connected to the plurality of main struts, Each of the plurality of main struts is substantially parallel to the axis when viewed from the outside in the radial direction, Each of the plurality of sub-struts has at least two joints joined to each of two adjacent main struts in the circumferential direction among the plurality of main struts, and at least two of the joints are arranged at different positions in the axial direction of the outer tube, In a cross-section perpendicular to the axis of the expansion body at any position where the sub-strut exists, the outermost position in the radial direction of the main strut in the natural state is located outside the outermost position in the radial direction of the sub-strut, The main strut has an outward convex portion protruding outward in the radial direction, The sub-strut is connected to the main strut on the tip side and the base end side rather than the outward convex portion, A medical device characterized in that in a cross-section perpendicular to the axis at the position where the outward convex portion is provided, the position of the outward convex portion in the natural state is located outside the outermost position in the radial direction of the sub-strut.

2. A long outer tube, An expansion body connected to the tip of the outer tube and expandable in the radial direction by contracting along the axis of the outer tube, A traction shaft disposed inside the outer tube, protruding from the tip of the outer tube and connected to the tip of the expansion body, and slidable with respect to the outer tube, The expansion body has a plurality of main struts arranged at intervals in the circumferential direction and extending a predetermined length along the axis of the outer tube, and a plurality of sub-struts connected to the plurality of main struts, Each of the plurality of main struts is substantially parallel to the axis when viewed from the outside in the radial direction, Each of the plurality of sub-struts has at least two joints joined to each of two adjacent main struts in the circumferential direction among the plurality of main struts, and at least two of the joints are arranged at different positions in the axial direction of the outer tube, In a cross-section perpendicular to the axis of the expansion body at any position where the sub-strut exists, the outermost position in the radial direction of the main strut in the natural state is located outside the outermost position in the radial direction of the sub-strut. The main strut has a tip-side clamping strut and a base-side clamping strut whose separation distance decreases as the expansion body expands. An inner convex portion protruding radially inward is formed between the tip-side clamping strut and the base-side clamping strut. The sub-strut is arranged on at least one of the tip side or the base side of the inner convex portion. A medical device characterized by this.

3. The plurality of sub-struts extend from each of two circumferentially adjacent main struts, and have two inclined struts inclined with respect to the axis when viewed from the outside in the radial direction, and a confluence portion where the two inclined struts are connected. The two inclined struts connected to the confluence portion are plane-symmetric with respect to a plane passing through the confluence portion and the axis of the expansion body. The medical device according to claim 1 or 2, characterized by this.

4. Two of the inclined struts provided on each sub-strut are tip-side inclined struts arranged side by side in the circumferential direction between two circumferentially adjacent main struts and connected to the main strut. Two of the inclined struts provided on each sub-strut are located on the base side of the tip-side inclined strut, arranged side by side in the circumferential direction between two circumferentially adjacent main struts, and are base-side inclined struts connected to the main strut. Each sub-strut has a confluence portion connecting the tip-side inclined strut and the base-side inclined strut. The medical device according to claim 3, characterized by this.

5. The medical device according to any one of claims 1 to 4, characterized by having an energy transmission element arranged on the expansion body and outputting energy.

6. A method for manufacturing an expansion body having a tip portion and a base portion, Prepare an expansion body having a plurality of main struts arranged at intervals in the circumferential direction and extending a predetermined length along an axis passing through the tip portion and the base portion, and a plurality of sub-struts connected to the plurality of main struts. A jig in which a plurality of small-diameter portions and a plurality of large-diameter portions having an outer diameter larger than that of the small-diameter portions are alternately arranged in the circumferential direction is arranged inside the expansion body. A method for manufacturing an expansion body, characterized in that the plurality of main struts are arranged outside the plurality of large-diameter portions in the radial direction to deform the plurality of main struts into a shape along the plurality of large-diameter portions, and the plurality of sub-struts are arranged outside the plurality of small-diameter portions in the radial direction to deform the sub-struts into a shape along the plurality of small-diameter portions.

7. The method for manufacturing an expansion body according to claim 6, characterized in that when deforming the plurality of main struts and the plurality of sub-struts, the plurality of main struts are pressed against the plurality of large-diameter portions, and the plurality of sub-struts are pressed against the plurality of small-diameter portions.

8. The jig has a first jig arranged inside the tip side of the expansion body and a second jig arranged inside the base end side of the expansion body. At least one of the first jig and the second jig has the plurality of small-diameter portions and the plurality of large-diameter portions. The first jig has a first inclined surface at its base end portion, and the outer diameter of the first jig decreases as it goes toward the base end. The second jig has a second inclined surface at its tip portion, and the outer diameter of the second jig decreases as it goes toward the tip. When arranging the jig inside the expansion body, a constricted portion constricted inward is formed from the first inclined surface and the second inclined surface. The method for manufacturing an expansion body according to claim 6 or 7, characterized in that the plurality of main struts and the plurality of sub-struts are pressed against the constricted portion to deform them into a shape along the constricted portion.

9. The method for manufacturing an expansion body according to claim 8, characterized in that the first jig and the second jig are arranged separately when arranging the jig inside the expansion body, and they come into contact with each other when deforming the plurality of main struts and the plurality of sub-struts into a shape along the constricted portion.

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