Medical device

Abstract

Provided is a medical device that can suppress a decrease in joining strength and difficulty in assembly due to a difference between an inner diameter of a fixing portion of an expansion body that is assembled to a shaft portion and an outer diameter of the shaft portion.　This medical device (10) is provided with an expansion body (21) formed by a plurality of struts (50) extending along an axial direction and arranged in a circumferential direction surrounding the axial direction, and a long shaft portion (31) connected to a base end fixing portion (52) formed at a base end portion of the expansion body (21). The base end fixing portion (52) has at least one opposing portion (63) having a pair of opposing edge portions (64) that can approach and separate from each other in the circumferential direction. The base end fixing portion (52) has a connecting structure that connects the pair of opposing edge portions (64) while being capable of changing the circumferential distance between the pair of edge portions (64) in a state before being connected to the shaft portion (31).

Description

medical devices

[0001] The present invention relates to medical devices.

[0002] To expand a through-hole in a medical biological lumen or biological membrane, an expandable body made of a shape memory alloy is used, which can be inserted into a living body in a contracted state and can expand in diameter within the living body (see, for example, Patent Document 1). The expandable body is attached to the distal end of a long shaft so that it can be transported to a predetermined position within the living body.

[0003] International Publication No. 2020-0259492

[0004] In a medical device in which an expansion body is assembled to a shaft, if the fixing portion of the expansion body relative to the shaft portion is cylindrical or ring-shaped and the diameter does not change, the bonding strength may be reduced due to the clearance between the outer diameter of the assembled shaft and the inner diameter of the fixing portion.

[0005] Furthermore, when the expansion body is made by cutting it out from a tube material, the dimensions of the fixing part depend on the dimensions of the tube material, so if the outer diameter of the shaft is larger than the inner diameter of the tube material, it becomes difficult to assemble the fixing part to the shaft.

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a medical device that can prevent a decrease in bonding strength or difficulty in assembly due to the difference between the inner diameter of the fixing part of the expansion body that is assembled to the shaft part and the outer diameter of the shaft part.

[0007] (1) The medical device of the present invention, which achieves the above-mentioned object, comprises an expansion body formed by a plurality of struts extending along an axial direction and arranged circumferentially surrounding the axial direction, and a long shaft portion connected to a fixing portion formed at the base end of the expansion body, wherein the fixing portion has at least one opposing portion having a pair of opposing edge portions that can approach and move away from each other in the circumferential direction, and the fixing portion has a connecting structure that connects the pair of opposing edge portions while being able to change the circumferential distance between the pair of edge portions before being connected to the shaft portion.

[0008] The medical device described in (1) above has a connecting structure for the fixing portion, which allows the circumferential length of the fixing portion to be appropriately adjusted to match the outer diameter of the shaft portion, thereby fixing the fixing portion to the shaft portion. Therefore, the medical device can prevent a decrease in bonding strength or difficulty in assembly due to a difference between the inner diameter of the fixing portion of the expandable body to be assembled to the shaft portion and the outer diameter of the shaft portion.

[0009] (2) In the medical device described in (1) above, the fixing portion may have a plurality of opposing portions spaced apart in the circumferential direction, each of the opposing portions including the pair of edge portions, and the connecting structure may have a plurality of connecting structures that can widen the circumferential distance between the pair of edge portions in each of the opposing portions. This allows the circumferential length of the fixing portion to be more appropriately adjusted to match the outer diameter of the shaft portion.

[0010] (3) In the medical device described in (1) or (2) above, at least one of the multiple connecting structures may have two joints joined to the pair of opposing edge portions, respectively, and a connecting strut formed longer than the linear distance between the two joints when viewed from the outside in the radial direction. This allows the connecting strut to deform so as to separate the two joints. Therefore, the medical device allows the circumferential length of the fixing portion to be adjusted to match the outer diameter of the shaft portion by deformation of the connecting strut. Therefore, even if the outer diameter of the shaft portion varies, the fixing portion can be securely fixed to the shaft portion. Furthermore, because at least one of the multiple connecting structures in the medical device has a connecting strut, it is possible to prevent the pair of edge portions from being completely separable and prone to coming apart in all connecting structures. Therefore, the medical device can suppress a decrease in workability when fixing the fixing portion to the shaft portion.

[0011] (4) In the medical device described in (3) above, the connecting strut may have a zigzag structure, whereby the connecting strut can be easily deformed to stretch the zigzag structure and thus easily deformed to separate the two joints.

[0012] (5) In the medical device described in any one of (2) to (4) above, at least one of the plurality of connecting structures has a concave-convex structure including a convex portion formed on one of the pair of edge portions of a corresponding one of the plurality of opposing portions and protruding circumferentially toward the other edge portion, and a concave portion formed on the other of the pair of edge portions of the corresponding one of the plurality of opposing portions and into which the convex portion fits, the convex portion having a base portion formed at one circumferential end and an apex portion formed at the other circumferential end and having a longer length in the axial direction of the expansion body than the base portion, the concave portion having an open apex portion that receives the base portion of the convex portion and an open bottom portion that communicates with the open apex portion and receives the apex of the convex portion, the circumferential length of the apex portion being shorter than the circumferential length of the open bottom portion, the convex portion fitting into the concave portion, and the base end portion of the expansion body being fixed to the shaft portion in a state in which the convex portion fits into the concave portion and a circumferential gap is formed between the apex of the convex portion and the open bottom portion of the concave portion. This allows the medical device to fix the expandable body to the shaft portion by connecting the top of the convex portion to the bottom of the opening of the recess. Furthermore, because a circumferential gap is formed between the top of the convex portion and the bottom of the opening of the recess, the circumferential length of the fixing portion can be appropriately adjusted to match the outer diameter of the shaft portion. Therefore, even if the outer diameter of the shaft portion varies, the fixing portion can be securely fixed to the shaft portion. Furthermore, the medical device allows the pair of edges of the opposing portions to be completely separated by removing the convex portion from the recess. Therefore, since at least one of the multiple connecting structures of the medical device has a completely separable convex portion and recess, it is possible to prevent the pair of edges from becoming completely separable in all connecting structures. Therefore, the medical device allows the opposing portions of the medical device to be widely spread and the fixing portion to be placed over the shaft portion, improving the workability when fixing the fixing portion to the shaft portion.

[0013] (6) In the medical device described in (5) above, the plurality of connecting structures may have two of the concave-convex structures provided so as to enable the fixing portion to be divided into a first fixing portion and a second fixing portion in the circumferential direction, thereby enabling the fixing portion of the medical device to be divided into two, making it easier to insert the shaft portion into the fixing portion.

[0014] (7) In the medical device described in (6) above, the plurality of connecting structures may include a plurality of connecting struts, at least one of which is provided on each of the first fixing portion and the second fixing portion, and each of the plurality of connecting struts may have two junctions joined to each of the pair of edge portions of a corresponding one of the plurality of opposing portions, and may be formed to be longer than the linear distance between the two junctions as viewed from the outside in the radial direction. In this way, the medical device has connecting struts on each of the two divided first fixing portion and second fixing portion, making it easier to insert the shaft portion and allowing it to expand more evenly in the circumferential direction.

[0015] (8) In the medical device described in (1) to (7) above, the multiple connecting structures may be arranged approximately evenly in the circumferential direction. This allows the cross-sectional shape of the inner circumferential surface of the fixing portion to remain nearly circular even when the circumferential length of the fixing portion is changed, allowing the fixing portion to be firmly attached to the shaft portion. Furthermore, the medical device allows the fixing portion to be spread evenly in the circumferential direction, making it easy to position the fixing portion in an appropriate position relative to the shaft portion. This improves the workability of the medical device when fixing the fixing portion to the shaft portion.

[0016] 1 is a side view showing a medical device according to the present embodiment; FIG. 2 is a side view showing the tip of the medical device; FIG. 3 is a side view showing an expansion body before it is fixed to the shaft portion; FIG. 4 is a side view showing the tip of the expansion body; FIG. 5 is a side view showing the base end of the expansion body, where (A) shows the portion including the first connecting structure and (B) the portion including the second connecting structure; FIG. 6 is a front view of the expansion body as viewed from the axial direction, where (A) shows the expansion body of this embodiment and (B) shows a modified expansion body; FIG. 7 is a side view showing the state in which the circumferential length of the base end fixing portion of the expansion body has been extended and placed over the shaft portion, where (A) shows the portion including the first connecting structure and (B) the portion including the second connecting structure; FIG. 8 is a side view showing the state in which the base end fixing portion of the expansion body has been fixed to the shaft portion, where (A) shows the portion including the first connecting structure and (B) the portion including the second connecting structure. FIG. 9 is a side view showing a modified medical device.

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the dimensional proportions in the drawings may be exaggerated for convenience of explanation and may differ from the actual proportions. In addition, in this specification, the side of the medical device 10 that is inserted into a body cavity will be referred to as the "distal side," and the side that is operated will be referred to as the "proximal side."

[0018] As shown in Figures 1 and 2, the medical device 10 of this embodiment is configured to expand a puncture hole formed in the atrial septum of a patient's heart and to perform a maintenance procedure to maintain the expanded puncture hole at that size.

[0019] The medical device 10 has a long portion 20 extending from the base end to the tip, an expansion body 21 provided at the tip end of the long portion 20, an electrode portion 22 which is an energy transmission element provided along the expansion body 21, and a hand-operated operating portion 23 connected to the base end of the long portion 20.

[0020] The long portion 20 has a shaft portion 31 that holds the expansion body 21 at its tip, a tip shaft portion 34 that is fixed to the tip of the expansion body 21, an outer tube 30 that houses the shaft portion 31, a traction shaft 33, and a tip tip 35 that is fixed to the tip of the traction shaft 33.

[0021] The shaft portion 31 is a long tubular body extending from the hand-operated operation unit 23 to at least the base end of the expansion body 21. The base end of the shaft portion 31 is fixed to the tip end of the hand-operated operation unit 23. The tip end of the shaft portion 31 is fixed to the base end of the expansion body 21. In this embodiment, the tip end of the shaft portion 31 extends to the inside of the expansion body 21, and the tip of the shaft portion 31 is located near the center of the expansion body 21 in the axial direction. The tip shaft portion 34 is a tubular body fixed to the tip end of the expansion body 21. The tip shaft portion 34 is positioned closer to the tip of the shaft portion 31 and spaced apart from the shaft portion 31.

[0022] The outer tube 30 is a long tubular body that covers the shaft portion 31 and is movable back and forth in the axial direction (toward the axis of the long portion 20 and the shaft portion 31) relative to the shaft portion 31. When the outer tube 30 is moved toward the distal end of the long portion 20, it can house the expandable body 21, which has been contracted radially, inside it. The radial direction is a direction perpendicular to the axis of the shaft portion 31. By moving the outer tube 30 toward the proximal end from a state in which the expandable body 21 is housed, the surgeon can expose the expandable body 21 from the outer tube 30 and cause it to expand radially due to the restoring force of the expandable body 21.

[0023] The traction shaft 33 is a long tubular body disposed inside the shaft portion 31 and the distal shaft portion 34, and is movable back and forth in the axial direction relative to the shaft portion 31. The traction shaft 33 protrudes distally from the distal end of the shaft portion 31, and protrudes distally from the distal end of the expansion body 21. The distal end of the traction shaft 33, which is located distally of the expansion body 21, is fixed to the distal tip 35. The proximal end of the traction shaft 33 is led out proximally from the proximal operation unit 23. A guidewire lumen is formed inside the traction shaft 33 along the axial direction, allowing a guidewire to be inserted therethrough. The traction shaft 33 is movable relative to the shaft portion 31 along the axial direction.

[0024] The distal tip 35 is an annular member fixed to the outer peripheral surface of the distal end of the traction shaft 33, and protrudes radially outward from the outer peripheral surface of the traction shaft 33. The distal tip 35 is not fixed to the expansion body 21. The outer diameter of the distal tip 35 is larger than the inner diameter of the distal end of the expansion body 21. Therefore, the distal tip 35 abuts against the distal end of the expansion body 21 from the distal side, and pulls the expansion body 21 toward the proximal end, thereby applying a compressive force to the expansion body 21 that compresses it along the axial direction of the shaft portion 31.

[0025] The expandable body 21 has multiple struts 50 extending axially and aligned circumferentially. The struts 50 branch and merge axially to form a mesh-like structure. This allows the expandable body 21 to expand and contract radially. The multiple struts 50 include multiple distal struts 50A located distally of a waist portion 55 where the outer diameter decreases, and multiple proximal struts 50B located proximal to the waist portion 55. The proximal struts 50B form multiple (two in this embodiment) strut groups 50C. The proximal struts 50B included in each strut group 50C are connected to the same separation portion 67, which will be described later.

[0026] The expandable body 21 can be formed by laser cutting or the like from a single metal cylindrical member. The expandable body 21 can be formed from a metal material. Examples of such metal materials include titanium-based alloys (Ti-Ni, Ti-Pd, Ti-Nb-Sn, etc.), copper-based alloys, stainless steel, β-titanium steel, and Co-Cr alloys. It is preferable to use a shape-memory alloy with superelasticity, such as a nickel-titanium alloy, so that the expandable body 21 can self-expand from a contracted state to its natural radially expanded state. However, the material of the expandable body 21 is not limited to these, and other materials may also be used. As shown in FIG. 3 , the expandable body 21 has multiple cuts 62 formed through it from the outer circumferential surface to the inner circumferential surface, and struts 50 are formed between adjacent cuts 62.

[0027] The expandable body 21 is tapered so that its diameter increases radially from both axial ends toward the center. The expandable body 21 also has a constricted shape in the axial center, where its outer diameter rapidly decreases. Specifically, the expandable body 21 includes a ring-shaped distal fixation portion 51 located at the distal end, a ring-shaped proximal fixation portion 52 (fixation portion) located at the proximal end, a distal convex portion 53 located at the proximal end of the distal fixation portion 51 and protruding radially outward, a proximal convex portion 54 located at the distal end of the proximal fixation portion 52 and protruding radially outward, and a waist portion 55 located between the distal convex portion 53 and the proximal convex portion 54, whose outer diameter decreases.

[0028] 2 to 4, the distal end fixing portion 51 is a ring-shaped portion formed by connecting the distal ends of a plurality of circumferentially arranged distal end struts 50A. The distal end fixing portion 51 is fixed to the distal end shaft portion .

[0029] The waist portion 55 has a bottom portion 56 that is the innermost in the radial direction, a base end side upright portion 57 that extends radially outward from the base end of the bottom portion 56, and a tip end side upright portion 58 that extends radially outward from the tip end of the bottom portion 56. The waist portion 55 defines a receiving space 59 that can receive biological tissue when the expandable body 21 is expanded.

[0030] The proximal end fixing portion 52 is a ring-shaped portion formed by connecting the proximal ends of a plurality of circumferentially arranged proximal end struts 50B. The proximal end fixing portion 52 is fixed to the shaft portion 31.

[0031] When the traction shaft 33 slides relative to the shaft portion 31 in the proximal direction and a compressive force acts on the expandable body 21, the distal upright portion 58 and the proximal upright portion 57 approach each other and come into close contact with the biological tissue received in the receiving space 59. The proximal upright portion 57 has an electrode portion 22 arranged along the waist portion 55 so as to face the receiving space 59. That is, the electrode portion 22 is provided along the expandable body 21, at a middle portion in the axial direction of the expandable body 21. In this embodiment, ten electrode portions 22 are provided along the circumferential direction. The electrode portion 22 may also be arranged on the distal upright portion 58.

[0032] As shown in Figures 3 and 5, before being fixed to the shaft portion 31, the base-end fixing portion 52 is connected to a ring-shaped connecting portion 90 located on the base end side of the base-end fixing portion 52 by a cut portion 91. The ring-shaped connecting portion 90 is a ring-shaped portion formed over 360 degrees. The ring-shaped connecting portion 90 and the cut portion 91 are cut out integrally together with the expandable body 21 from the same metal cylindrical member. Note that Figures 5(A) and 5(B) show different circumferential portions of the base-end fixing portion 52, for example, portions that are 180 degrees apart in the circumferential direction.

[0033] 2, 3, 5, and 6(A), the base end fixing part 52 has two opposing portions 63 with opposing edge portions 64 that can move toward and away from each other in the circumferential direction, a first connecting structure 65 that connects the two opposing edge portions 64 in one of the opposing portions 63, and a second connecting structure 66 that connects the two opposing edge portions 64 in the other opposing portion 63. When the base end fixing part 52 has multiple opposing portions 63, the opposing portions 63 separate the base end fixing part 52 into multiple separation portions 67 in the circumferential direction. In the base end fixing part 52, the multiple connection structures (in this embodiment, the first connecting structures 65 and the second connecting structures 66) are preferably arranged evenly in the circumferential direction.

[0034] The first connecting structure 65 is a structure that allows two opposing edge portions 64 to be completely separated and also connect the separated two edge portions 64, and allows the two edge portions 64 to move in the circumferential direction only within a predetermined range when connected. As shown in FIG. 5A , the first connecting structure 65 has a T-shaped protrusion 70 and a recess 71 with a cutout of the T-shape. The protrusion 70 is formed on one of the two edge portions 64 that form the opposing portion 63, and the recess 71 is formed on the other of the two edge portions 64. The protrusion 70 can be connected by being hooked onto the recess 71, and can be completely separated by being released from the recess 71. The protrusion 70 has a base portion 72 formed at one circumferential end so as to be continuous with the edge portions 64, and an apex portion 73 formed at the other circumferential end and having a length longer than the base portion 72 in the axial direction of the expandable body 21. The recess 71 has an open top 74 that receives the base 72 of the protrusion 70, and an open bottom 75 that communicates with the open top 74 and receives the top 73 of the protrusion 70. The circumferential length of the top 73 is shorter than the circumferential length of the open bottom 75. The protrusion 70 fits into the recess 71, and a circumferential gap 76 is formed between the top 73 of the protrusion 70 and the open bottom 75 of the recess 71, and the base end of the expandable body 21 is fixed to the shaft 31 (see FIG. 8A ). Note that, in this embodiment, the top 73 protrudes both distally and proximally from the base 72; however, it may protrude only distally or proximally from the base 72. In the first connecting structure 65, the base portion 72 fits closely to the opening top portion 74 in the axial direction with almost no gap, and the top portion 73 fits closely to the opening bottom portion 75 in the axial direction with almost no gap, so that when the convex portion 70 moves within the recessed portion 71 while connected to the recessed portion 71, the two edge portions 64 are maintained in a parallel state. This makes it possible to prevent the circumferential length of the base end fixing portion 52 from differing between the distal end side and the proximal end side of the base end fixing portion 52, and makes it easier for the inner peripheral surface of the base end fixing portion 52 to fit closely to the outer peripheral surface of the shaft portion 31.

[0035] The second connecting structure 66 does not completely separate the two opposing edge portions 64, but allows the two edge portions 64 to move in the circumferential direction only within a predetermined range. As shown in FIG. 5B , the second connecting structure 66 has connecting struts 80 each having two joints 81 joined to each of the two edge portions 64 that form the opposing portion 63. The connecting struts 80 are formed to be longer than the linear distance (shortest distance) between the two joints 81 when viewed from the outside in the radial direction. As an example, the connecting struts 80 have a zigzag structure, extending linearly and approximately parallel from each of two circumferentially adjacent joints 81 in the axial direction (e.g., toward the distal end) and connecting at their distal end portions to form a turned-up portion 82. The length of the connecting strut 80 is the sum of the distance from one joint 81 to the turned-up portion 82 and the distance from the other joint 81 to the turned-up portion 82. The length of the connecting strut 80 is longer than the linear distance between the two joints 81. For this reason, the connecting struts 80 are prone to deformation such that the edge portions 64 separate circumferentially. The two joints 81 of the connecting struts 80 do not separate from the two edge portions 64, preventing the two edge portions 64 from completely separating. Unlike the first connecting structure 65, the second connecting structure 66 can generate a contractile force (fastening force with respect to the shaft portion 31) that reduces the inner diameter of the proximal end fixing portion 52 after expansion if the connecting struts 80 are elastically deformable. In this embodiment, one second connecting structure 66 includes one connecting strut 80, but it may also include multiple connecting struts 80. Furthermore, the connecting struts 80 are not limited to a zigzag structure. For example, a pantograph-like structure may be used in which four long sections are connected in a diamond shape, with two ends located at two opposing corners as joints 81 and the other two ends located at the other two corners as deformable free ends.

[0036] As shown in Fig. 5 , the proximal end of the proximal-end fixing part 52 has a recessed part 68 recessed toward the tip of the expandable body 21, a first recessed part 77, and a second recessed part 78. A cutting part 91 is connected to the proximal-end fixing part 52 within the recessed interior of the recessed part 68. The cutting part 91 is formed to taper from the ring-shaped connecting part 90 toward the recessed part 68. Therefore, the cutting part 91 can be cut at a position closer to the recessed part 68 than the ring-shaped connecting part 90. When the cutting part 91 is cut, a cut mark part 92 (see Fig. 7 ) is formed within the recessed interior of the recessed part 68.

[0037] The first cutout 77 is a cutout formed from the base end of the base end fixing portion 52 near the first connecting structure 65 toward the tip of the expansion body 21. The second cutout 78 is a cutout formed from the base end of the base end fixing portion 52 near the second connecting structure 66 toward the tip of the expansion body 21. The first cutout 77 and the second cutout 78 promote the flow of adhesive between the base end fixing portion 52 and the shaft portion 31.

[0038] The ring-shaped connecting portion 90 prevents the opposing portions 63 from widening (the opposing edge portions 64 from separating) in the first connecting structure 65 and the second connecting structure 66, and appropriately maintains the shape of the expandable body 21 until the work of fixing the expandable body 21 to the shaft portion 31 begins. In particular, the ring-shaped connecting portion 90 effectively prevents the opposing portions 63 from widening too much in the first connecting structure 65, which has opposing portions 63 whose two edge portions 64 can be completely separated by disengaging the convex portions 70 from the concave portions 71.

[0039] In the present embodiment, the proximal end fixed part 52 has two different connecting structures (a first connecting structure 65 and a second connecting structure 66). The proximal end fixed part 52 may have only one connecting structure (the first connecting structure 65 or the second connecting structure 66). Alternatively, the proximal end fixed part 52 may have three or more connecting structures. The proximal end fixed part 52 may have at least one first connecting structure 65 and at least one second connecting structure 66. The proximal end fixed part 52 may have only one or more first connecting structures 65, or only one or more second connecting structures 66. Furthermore, the proximal end fixed part 52 may have multiple connecting structures, and may have at least one first connecting structure 65 or at least two first connecting structures 65. When the proximal end fixed part 52 has at least two first connecting structures 65, it has at least two opposing parts 63 that are completely separable, and therefore can be widely expanded. However, if there are too many completely separable opposing portions 63, the workability of fixing the base end fixed portion 52 to the shaft portion 31 may be reduced. Therefore, it is preferable that two of the two or more connecting structures of the base end fixed portion 52 be first connecting structures 65. As an example, in a modified example shown in FIG. 6(B), the base end fixed portion 52 has two first connecting structures 65 and one second connecting structure 66. In another modified example shown in FIG. 6(C), the base end fixed portion 52 has two first connecting structures 65 and two second connecting structures 66, arranged alternately in the circumferential direction. The base end fixed portion 52 can be divided by the two first connecting structures 65 into a first fixing portion 52A and a second fixing portion 52B, each of which includes a second connecting structure 66.

[0040] When connecting the expandable body 21 to the shaft portion 31, the manufacturer cuts the cutting portion 91 to separate the ring-shaped connecting portion 90 from the proximal end fixing portion 52, as shown in FIG. 7(A). Next, the manufacturer removes the convex portion 70 of the first connecting structure 65 of the proximal end fixing portion 52 from the concave portion 71 and moves the two opposing edge portions 64 of the first connecting structure 65 so as to spread them apart. Furthermore, the manufacturer deforms the connecting struts 80 of the second connecting structure 66 of the proximal end fixing portion 52 so that the two joint portions 81 move apart, as shown in FIG. 7(B). The connecting struts 80 of the second connecting structure 66 can change the distance between the edges 64 within a predetermined range, from when the two joints 81 are in contact to when the connecting strut 80 is fully extended, i.e., from when the two joints 81 are in contact to when the two joints 81 and the folded-back portion 82 are aligned in a straight line. The connecting struts 80 preferably deform elastically, but may also deform plastically. This causes the two separation portions 67 of the proximal fixation portion 52 to separate, increasing the circumferential length of the proximal fixation portion 52. As a result, the manufacturer can easily place the proximal fixation portion 52 over the shaft portion 31. The manufacturer can then insert the shaft portion 31 into the proximal fixation portion 52.

[0041] Next, as shown in FIG. 8(A), the manufacturer connects the convex portion 70 of the first connecting structure 65 to the concave portion 71. At this time, the circumferential position of the apex 73 of the convex portion 70 within the opening bottom 75 of the concave portion 71 can be adjusted within the range of the gap 76. Furthermore, as shown in FIG. 8(B), the connecting struts 80 of the second connecting structure 66 of the proximal end fixing portion 52 can restore their original shape or a shape close to their original shape by their own elastic force, so as to bring the two joining portions 81 joined to the edge portion 64 closer together. Note that if the connecting struts 80 are plastically deformed when expanding, they may contract due to plastic deformation. Therefore, as shown in FIG. 8, even if the outer diameter of the shaft portion 31 varies, the proximal end fixing portion 52 is tightly connected to the shaft portion 31 by the first connecting structure 65 and the second connecting structure 66, with an inner diameter that matches the outer diameter of the shaft portion 31. Next, the manufacturer pours adhesive between the base end fixing portion 52 and the shaft portion 31 to fix the base end fixing portion 52 to the shaft portion 31. At this time, the adhesive can flow into the gap between the base end fixing portion 52 and the shaft portion 31 from the base end and tip of the base end fixing portion 52, the opposing portion 63, the first cutout portion 77, the second cutout portion 78, etc. This allows the base end fixing portion 52 to be firmly fixed to the shaft portion 31. Note that the method of fixing the base end fixing portion 52 to the shaft portion 31 is not limited to bonding with an adhesive, and may be, for example, soldering, welding, or fastening with a heat-shrink tube.

[0042] Next, as shown in Figure 2, the manufacturer assembles the multiple divided distal struts 50A onto the outer peripheral surface of the distal shaft portion 34 to form the distal fixing portion 51, and fixes it to the distal shaft portion 34 with an adhesive or the like, so as to prevent the distal end of the expansion body 21 from spreading apart due to the slits. Note that the distal struts 50A may also be fixed to the distal shaft portion 34 before connecting the expansion body 21 to the shaft portion 31. This makes it less likely for the entire expansion body 21 to come apart when connecting the expansion body 21 to the shaft portion 31, and makes it easier to fix the proximal fixing portion 52 to the shaft portion 31.

[0043] The electrode units 22 are disposed on the conductive portion 60 of the expansion body 21 and are connected to an external energy supply device (not shown) via the conductive portion 60. A high-frequency voltage is applied from the energy supply device via the conductive portion 60 to an electrode pair consisting of the two electrode units 22, thereby providing energy between them. In other words, the electrode units 22 are configured as bipolar electrodes.

[0044] When the expandable body 21 is expanded, the electrode 22 is disposed on the surface of the base-side upright portion 57 facing the distal end. Because the electrode 22 is provided on the base-side upright portion 57, when the waist portion 55 clamps the atrial septum, energy from the electrode 22 is transmitted to the atrial septum from the right atrium. If the electrode 22 were provided on the distal upright portion 58, energy from the electrode 22 would be transmitted to the atrial septum from the left atrium.

[0045] 1, the handheld operation unit 23 has a housing 40 that is held by the surgeon and an operation unit 41 that can be moved by the surgeon along the axial direction of the traction shaft 33. The housing 40 is fixed to the base end of the shaft unit 31, and the operation unit 41 is fixed to the base end of the traction shaft 33.

[0046] The medical device 10 is used in treatment of patients suffering from chronic heart failure, a condition in which the myocardium of the left ventricle of the heart becomes enlarged and stiff, resulting in elevated blood pressure in the left atrium. The medical device 10 is inserted partway through the expandable body 21 into a puncture hole in the atrial septum. The edge of the puncture hole formed in the atrial septum is positioned within the receiving space 59 defined by the waist portion 55. When the traction shaft 33 is pulled proximally relative to the shaft portion 31, a compressive force acts on the expandable body 21, causing the distal upright portion 58 and the proximal upright portion 57 to approach each other, and the electrode portion 22 disposed on the proximal upright portion 57 to be pressed against biological tissue. In this state, the medical device 10 applies high-frequency energy to the edge of the puncture hole through the electrode portion 22, thereby cauterizing (thermal cauterization) the edge of the puncture hole with high-frequency energy. This prevents the puncture hole from naturally healing and maintaining its size.

[0047] As described above, the medical device 10 according to this embodiment comprises an expansion body 21 formed by a plurality of struts 50 extending axially and aligned circumferentially around the axial direction, and a long shaft portion 31 connected to a proximal end fixing portion 52 formed at the proximal end of the expansion body 21, the proximal end fixing portion 52 having at least one opposing portion 63 with a pair of opposing edges 64 that can move toward and away from each other in the circumferential direction, and the proximal end fixing portion 52 has a connecting structure that connects the pair of opposing edges 64 while allowing the circumferential distance between the pair of edges 64 to be changed before being connected to the shaft portion 31. This allows the medical device 10 to fix the proximal end fixing portion 52 to the shaft portion 31 by appropriately adjusting the circumferential length of the proximal end fixing portion 52 to match the outer diameter of the shaft portion 31 due to the connecting structure of the proximal end fixing portion 52. Therefore, the medical device 10 can prevent a decrease in bonding strength or difficulty in assembly due to the difference between the inner diameter of the base end fixing portion 52 of the expansion body 21 to be assembled to the shaft portion 31 and the outer diameter of the shaft portion 31.

[0048] The base end fixing part 52 has a plurality of opposing parts 63 that are spaced apart in the circumferential direction, and each of the plurality of opposing parts 63 has a pair of edge parts 64. The connecting structure has a plurality of connecting structures that enable the circumferential distance between the pair of edge parts 64 to be increased in each of the plurality of opposing parts 63. This allows the circumferential length of the base end fixing part 52 to be more appropriately adjusted to match the outer diameter of the shaft part 31.

[0049] At least one of the multiple connecting structures has two joints 81 joined to each of a pair of opposing edge portions 64, and includes a connecting strut 80 that is longer than the linear distance between the two joints 81 when viewed from the outside in the radial direction. This allows the connecting strut 80 to deform so as to separate the two joints 81. Therefore, the medical device 10 can adjust the circumferential length of the proximal end fixing portion 52 to match the outer diameter of the shaft portion 31 by deforming the connecting strut 80. Therefore, even if the outer diameter of the shaft portion 31 varies, the proximal end fixing portion 52 can be securely fixed to the shaft portion 31. Furthermore, because at least one of the multiple connecting structures in the medical device 10 includes the connecting strut 80, it is possible to prevent the pair of edge portions 64 from being completely separable and prone to coming apart in all connecting structures. This prevents the medical device 10 from reducing the ease of fixing the proximal end fixing portion 52 to the shaft portion 31.

[0050] The connecting strut 80 may have a zigzag structure, which allows the connecting strut 80 to be easily deformed so as to stretch the zigzag structure, and therefore to easily deform so as to move the two joints 81 apart.

[0051] At least one of the plurality of connecting structures has a concave-convex structure including a convex portion 70 formed on one of a pair of edge portions 64 of a corresponding one of the plurality of opposing portions 63 and protruding in the circumferential direction toward the other, and a concave portion 71 formed on the other of the pair of edge portions 64 of the corresponding one of the plurality of opposing portions 63 and into which the convex portion 70 fits, and the convex portion 70 has a base portion 72 formed at one end in the circumferential direction and a base portion 72 formed at the other end in the circumferential direction and having a length in the axial direction of the expandable body 21 longer than that of the base portion 72. The recess 71 has an open top 74 that receives the base 72 of the protrusion 70 and an open bottom 75 that communicates with the open top 74 and receives the top 73 of the protrusion 70, the circumferential length of the top 73 being shorter than the circumferential length of the open bottom 75, and the proximal end of the expandable body 21 is fixed to the shaft portion 31 with the protrusion 70 fitted into the recess 71 and a circumferential gap 76 formed between the top 73 of the protrusion 70 and the open bottom 75 of the recess 71. This allows the medical device 10 to connect the top 73 of the protrusion 70 of the expandable body 21 to the open bottom 75 of the recess 71, thereby fixing the expandable body 21 to the shaft portion 31. Furthermore, because the circumferential gap 76 is formed between the top 73 of the protrusion 70 and the open bottom 75 of the recess 71, the circumferential length of the base-end fixing portion 52 can be appropriately adjusted to match the outer diameter of the shaft portion 31. Therefore, even if the outer diameter of the shaft portion 31 varies, the proximal end fixing portion 52 can be securely fixed to the shaft portion 31. Furthermore, in the medical device 10, the pair of edge portions 64 of the facing portion 63 can be completely separated by removing the convex portion 70 from the concave portion 71. Therefore, since the medical device 10 has at least one of the multiple coupling structures that has a completely separable convex portion 70 and concave portion 71, it is possible to prevent the pair of edge portions 64 from becoming completely separable in all coupling structures. Therefore, in the medical device 10, the facing portion 63 can be widely spread to place the proximal end fixing portion 52 over the shaft portion 31, improving the workability when fixing the proximal end fixing portion 52 to the shaft portion 31.

[0052] The multiple connecting structures may have two concave-convex structures that allow the base end fixing portion 52 to be divided in the circumferential direction into a first fixing portion 52A and a second fixing portion 52B. This allows the base end fixing portion 52 of the medical device 10 to be divided into two, making it easier to insert the shaft portion 31 into the base end fixing portion 52.

[0053] The multiple connecting structures include multiple connecting struts 80, at least one of which is provided on each of the first fixing portion 52A and the second fixing portion 52B, and each of the multiple connecting struts 80 has two joints 81 joined to each of a pair of edge portions 64 on a corresponding one of the multiple opposing portions 63, and may be formed to be longer than the linear distance between the two joints 81 when viewed from the outside in the radial direction. In this way, the medical device 10 has connecting struts 80 on each of the two divided first fixing portion 52A and second fixing portion 52B, making it easier to insert the shaft portion 31 and allowing it to expand more evenly in the circumferential direction.

[0054] In the medical device 10, the multiple connecting structures are evenly arranged in the circumferential direction. As a result, even if the circumferential length of the proximal end fixing portion 52 is changed, the cross-sectional shape of the inner circumferential surface of the proximal end fixing portion 52 can be maintained at a shape close to a circle, and the proximal end fixing portion 52 can be firmly attached to the shaft portion 31. Furthermore, in the medical device 10, the proximal end fixing portion 52 can be evenly spread in the circumferential direction, making it easy to position the proximal end fixing portion 52 in an appropriate position relative to the shaft portion 31. Therefore, the medical device 10 can improve the workability when fixing the proximal end fixing portion 52 to the shaft portion 31.

[0055] The present invention is not limited to the above-described embodiment, and various modifications may be made by those skilled in the art within the technical spirit of the present invention. For example, the connecting structure may be formed in the distal fixing portion 51 rather than the proximal fixing portion 52. Furthermore, as shown in the modified example in FIG. 9 , the expandable body 21 may not have a distal fixing portion. The medical device 100 has at least one pulling wire 101 connected to the operating unit 41 instead of the pulling shaft 33. The distal end of the pulling wire 101 is fixed to the waist portion 55. Therefore, the diameter of the waist portion 55 can be adjusted by moving the pulling wire 101 in the proximal direction using the operating unit 41.

[0056] Furthermore, the above-described first connecting structure 65 and second connecting structure 66 may be arranged side by side in the axial direction in one opposing portion 63. In other words, the first connecting structure 65 and the second connecting structure 66 having different structures may be combined to form one connecting structure.

[0057] This application is based on Japanese Patent Application No. 2024-028338 filed on February 28, 2024, the disclosures of which are incorporated herein by reference in their entirety.

[0058] DESCRIPTION OF SYMBOLS 10 Medical device 21 Expansion body 31 Shaft portion 50 Strut 51 Distal fixing portion 52 Base end fixing portion (fixing portion) 52A First fixing portion 52B Second fixing portion 55 Waist portion 63 Opposing portion 64 Edge portion 65 First connecting structure (connecting structure) 66 Second connecting structure (connecting structure) 70 Convex portion 71 Concave portion 72 Base portion 73 Top portion 74 Opening top portion 75 Opening bottom portion 76 Gap 80 Connecting strut 81 Joint portion

Claims

1. A medical device comprising: an expansion body formed by a plurality of struts extending along an axial direction and arranged circumferentially surrounding the axial direction; and a long shaft portion connected to a fixing portion formed at the base end of the expansion body, wherein the fixing portion has at least one opposing portion having a pair of opposing edge portions that can move toward and away from each other in the circumferential direction, and wherein the fixing portion has a connecting structure that connects the pair of opposing edge portions while being able to change the circumferential distance between the pair of edge portions before being connected to the shaft portion.

2. The medical device described in claim 1, characterized in that the fixing portion has a plurality of opposing portions spaced apart in the circumferential direction as the opposing portions, each of the plurality of opposing portions having the pair of edge portions, and the connecting structure has a plurality of connecting structures in each of the plurality of opposing portions that can widen the circumferential distance between the pair of edge portions.

3. The medical device described in claim 2, characterized in that at least one of the multiple connecting structures has two joints joined to each of the pair of opposing edges, and has a connecting strut formed to be longer than the linear distance between the two joints when viewed from the radially outer side.

4. The medical device of claim 3, wherein the connecting struts are zigzag.

5. A medical device according to any one of claims 2 to 4, characterized in that at least one of the multiple connecting structures has a concave-convex structure comprising a convex portion formed on one of the pair of edge portions of a corresponding one of the multiple opposing portions and protruding circumferentially toward the other edge portion, and a concave portion formed on the other of the pair of edge portions of the corresponding one of the multiple opposing portions and into which the convex portion fits, wherein the convex portion has a base portion formed at one circumferential end and an apex portion formed at the other circumferential end and having a longer length in the axial direction of the expansion body than the base portion, wherein the concave portion has an open apex portion that receives the base portion of the convex portion, and an open bottom portion that communicates with the open apex portion and receives the apex of the convex portion, the circumferential length of the apex being shorter than the circumferential length of the open bottom portion, and wherein the base end of the expansion body is fixed to the shaft portion with the convex portion fitting into the concave portion and a circumferential gap being formed between the apex of the convex portion and the open bottom of the concave portion.

6. A medical device as described in claim 5, characterized in that the multiple connecting structures have two of the uneven structures arranged so that the fixing portion can be divided into a first fixing portion and a second fixing portion in the circumferential direction.

7. The medical device described in claim 6, characterized in that the multiple connecting structures have multiple connecting struts, at least one of which is provided on each of the first fixing portion and the second fixing portion, and each of the multiple connecting struts has two joints joined to each of the pair of edge portions on a corresponding one of the multiple opposing portions, and is formed to be longer than the linear distance between the two joints when viewed from the radially outward side.

8. A medical device according to any one of claims 1 to 4, characterized in that the plurality of connecting structures are arranged approximately evenly in the circumferential direction.

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