Medical device

Abstract

Provided is a medical device in which a decrease in strength of a shaft, in which a shaft body is covered with an outer layer, can be suppressed, even when a shaft joint and an outer layer joint are included. A medical device 10 includes: an electrode support 21; and a shaft 20 joined to a base end part of the electrode support 21. The shaft 20 includes: a shaft body 60; an outer layer 65 covering the outside of the shaft body 60; and a conductor part 80 sandwiched between the shaft body 60 and the outer layer 65 and electrically connected to an electrode assembly 22 at a contact part 85. In the shaft body 60, a first shaft body part 61 and a second shaft body part 62 are joined at a shaft joint 63. In the outer layer 65, a first outer layer 66 and a second outer layer 67 are joined at an outer layer joint 68. The contact part 85 is located on the second shaft body part 62 side, and the shaft joint 63 and the outer layer joint 68 are arranged at different positions in the axial direction of the shaft 20.

Description

Medical device

[0001] The present invention relates to a medical device that applies energy to biological tissue.

[0002] As a medical device, there is known one in which an electrode section is disposed on an electrode support provided at the distal end of an elongated shaft, and ablation treatment is performed to cauterize biological tissue by high-frequency current from the electrode section. As one type of ablation treatment, shunt treatment for the atrial septum is known. Shunt treatment enables alleviation of heart failure symptoms by forming a shunt (communication hole) serving as an escape path for increased atrial pressure in the fossa ovalis of the atrial septum for heart failure patients. In shunt treatment, the atrial septum is accessed via a transvenous approach to form a shunt of a desired size.

[0003] Each electrode section forms an electrode assembly together with an elongated wiring section for supplying power. A conductive wire portion extending from the proximal side to the distal end of the medical device is electrically connected to the electrode assembly. The shaft has an outer layer on the outer peripheral side of the shaft main body along the radial direction, and the conductive wire portion is disposed between the shaft main body and the outer layer. As an example of a medical device in which a conductive wire portion is disposed between a shaft main body and an outer layer, one disclosed in Patent Document 1 is known.

[0004] Japanese National Publication of International Patent Application No. 2012-510831

[0005] In the medical device used for the aforementioned shunt treatment, the distal end of the shaft is bent or curved in order to place the electrode support on the atrial septum within the heart. For this reason, while the distal end of the shaft is easily bent or curved, the shaft needs to have a certain degree of rigidity as a whole. To achieve this, the shaft is configured by integrally joining resins having different rigidities along the axial direction near the distal end portion. Accordingly, the shaft has a shaft joint portion near the distal end portion.

[0006] The conductor is wound along the axial direction of the shaft body, and then an outer layer is provided to cover the outside of the shaft body, so that it is positioned between the shaft body and the outer layer. In order to connect the tip of the conductor to the electrode assembly, the first outer layer, which is initially provided, does not cover the tip of the shaft body, and after the conductor is connected to the electrode assembly, a second outer layer is provided to cover the tip of the shaft body. For this reason, the outer layer has an outer layer joint where the first outer layer and the second outer layer are joined together.

[0007] The shaft joints and outer layer joints are areas where two materials are joined, and therefore have lower strength than other parts. To prevent shaft fracture, it is necessary to suppress the reduction in strength in shafts that have shaft joints and outer layer joints.

[0008] The present invention was made to solve the above-mentioned problems, and aims to provide a medical device in which a shaft body covered with an outer layer can suppress a decrease in strength even when it has a shaft joint and an outer layer joint.

[0009] A medical device (1) according to the present invention that achieves the above objectives comprises an electrode support that supports an electrode assembly including an electrode portion for applying energy to biological tissue, and a shaft joined to the base end of the electrode support, wherein the shaft comprises a shaft body extending in the axial direction, an outer layer covering the outside of the shaft body, and a conductor portion sandwiched between the shaft body and the outer layer and electrically connected to the electrode assembly at a contact portion, wherein the shaft body comprises a first shaft body portion extending from the base end to the tip side, and a second shaft body portion joined at a shaft joint portion at the tip of the first shaft body portion, wherein the outer layer comprises a first outer layer extending from the base end to the tip side of the first shaft body portion, and a second outer layer joined at an outer layer joint portion at the tip of the first outer layer, wherein the contact portion is located between the second shaft body portion and the second outer layer, and the shaft joint portion and the outer layer joint portion are located at different positions in the axial direction of the shaft.

[0010] A method for manufacturing a medical device (8) according to the present invention that achieves the above objective, comprising: an electrode support that supports an electrode assembly including an electrode portion for applying energy to biological tissue; and a shaft joined to the base end of the electrode support, wherein the shaft comprises: a shaft body extending in the axial direction; an outer layer covering the outside of the shaft body; and a conductor portion sandwiched between the shaft body and the outer layer and electrically connected to the electrode assembly at a contact portion, the method for manufacturing a medical device comprising: a step of joining a second shaft body portion in the axial direction to the tip of a first shaft body portion to form the shaft body having a shaft joint portion; and the shaft body The steps include: arranging a conductor portion on the base end region from the base end to just before the tip region; providing a first outer layer so as to cover the outside of the base end region of the shaft body, including the conductor portion arranged on the base end region of the shaft body; electrically connecting the conductor portion exposed towards the tip side of the first outer layer with the electrode assembly to form the contact portion; and providing a second outer layer so as to cover the outside of the tip region of the shaft body, including the conductor portion exposed towards the tip side of the first outer layer and the contact portion, and joining it with the first outer layer to form an outer layer having an outer layer joint portion that is in a different axial position from the shaft joint portion.

[0011] As described above, in the medical device (1), the shaft joint and the outer layer joint, which have reduced strength, are positioned at different locations in the axial direction of the shaft. Therefore, even in a shaft where the shaft body is covered with an outer layer, a decrease in strength can be suppressed even if the shaft joint and the outer layer joint are present.

[0012] (2) In the medical device described in (1) above, the outer layer joint may be positioned on the tip side of the shaft joint. This makes it possible to shorten the length of the conductor portion sandwiched between the tip of the shaft body after it has been covered with the first outer layer and the second outer layer during the manufacturing of the shaft, thereby facilitating the manufacturing process.

[0013] (3) In the medical device described in (1) or (2) above, the conductor portion may be wound around the outer circumference of the shaft body and sandwiched between the shaft body and the outer layer. This makes it possible for the medical device to maintain a constant bending characteristic of the shaft along the axial direction and to facilitate insertion of the shaft into a blood vessel.

[0014] (4) In any of the medical devices described in (1) to (3) above, the conductor portion may have a first conductor portion and a second conductor portion, and the first conductor portion and the second conductor portion may be wound around the shaft body at a distance of 180° from each other in the circumferential direction. This makes it less likely for the conductor portion to break when the shaft is bent, and also makes it possible to suppress the influence of the current flowing through the first conductor portion and the second conductor portion on the current of the other conductor portion.

[0015] (5) In the medical device described in (4) above, the conductor portion may be wound around the shaft body such that the distance along the axial direction between two axially adjacent conductor portions between the first conductor portion and the second conductor portion is 1.0 to 2.0 times the diameter of the shaft body. This makes it possible to suppress breakage of the conductor portion due to bending of the shaft and to suppress the influence of currents and voltage loss.

[0016] (6) In any of the medical devices described in (1) to (5) above, the second shaft body may have lower rigidity than the first shaft body. This makes it easier to bend the tip of the shaft in the medical device, thereby facilitating the placement of the electrode support at the target site.

[0017] (7) In any of the medical devices described in (1) to (6) above, the shaft may have a curved or bent portion at a position toward the tip of the shaft joint and the outer layer joint, and toward the base of the contact portion. This allows the medical device to be configured such that the curved or bent portion of the shaft does not affect the shaft joint, the outer layer joint, and the contact portion.

[0018] The method for manufacturing a medical device (8) configured as described above can manufacture a medical device having a shaft in which the shaft joint and the outer layer joint, which have lower strength, are positioned at different locations in the axial direction of the shaft.

[0019] (9) In the method for manufacturing the medical device described in (8) above, when providing the first outer layer, a reduced diameter portion may be formed at the tip of the first outer layer, and when providing the second outer layer, the base end of the second outer layer may be positioned to overlap with the reduced diameter portion. This makes it less likely for steps to occur at the outer layer joint in the method for manufacturing the medical device.

[0020] (10) In the method for manufacturing a medical device according to (8) or (9) above, the second shaft body may have lower rigidity than the first shaft body. This makes it possible to manufacture a medical device in which the tip of the shaft having an electrode support can be easily bent.

[0021] (11) In any of the methods for manufacturing a medical device described in (8) to (10) above, the conductor portion may be wound around the base end region of the shaft body, and a first outer layer may be provided so as to cover the outside of the base end region of the shaft body, including the conductor portion wound around the base end region. This ensures that the conductor portion is wound around the base end region of the shaft body, thereby suppressing breakage of the conductor portion due to bending of the shaft.

[0022] (12) In any of the methods for manufacturing a medical device described in (8) to (11) above, the conductor portion exposed to the tip side of the first outer layer may be wound around the tip region of the shaft body, and a second outer layer may be provided so as to cover the outside of the tip region of the shaft body, including the conductor portion and the contact portion wound around the tip region. This ensures that the conductor portion is wound around the tip region of the shaft body, thereby suppressing breakage of the conductor portion due to bending of the shaft.

[0023] (13) In any of the methods for manufacturing a medical device described in (8) to (12) above, the method may further include the step of bending or curving the shaft at a position that is closer to the tip than the shaft joint and the outer layer joint, and closer to the base than the contact portion, with the conductor portion and the contact portion wound around the tip region of the shaft body sandwiched between the shaft body and the outer layer. This allows the method for manufacturing a medical device to form a bent portion or curved portion at the tip of the shaft without affecting the shaft joint, the outer layer joint, and the contact portion.

[0024] This is a front view showing the overall configuration of the medical device according to the embodiment. This is an enlarged perspective view of the area near the expandable body. This is an enlarged front view of the area near the expandable body. This is an enlarged view of the area near the tip of the shaft where the electrode assembly and the conductor portion are provided. This is an enlarged front view of the shaft and a simplified representation of the expandable body. This is an enlarged view of the area near the tip of the shaft having a bent portion. This is a diagram showing the manufacturing process of the shaft. This is an enlarged view of the area near the tip of the first outer layer in a state where the first outer layer is provided on the outside of the shaft body. This is an enlarged diagram illustrating the process of providing a second outer layer on the outside of the shaft body, where (a) shows the state in which the second outer layer is placed so as to overlap the first outer layer, and (b) shows the state in which the first outer layer and the second outer layer are joined together. This is a diagram showing the tip of the shaft attached to a jig for forming a bent portion. This is an explanatory diagram schematically showing the state in which the expandable body is placed in the atrial septum, with the medical device shown in a front view and the biological tissue in a cross-sectional view. This is an enlarged front view showing the state in which the expandable body grasps the biological tissue.

[0025] Embodiments of the present invention will be described below with reference to the drawings. Note that the dimensional ratios in the drawings may be exaggerated for illustrative purposes and may differ from the actual ratios. In this specification, the side of the medical device 10 that is inserted into the lumen of the body will be referred to as the "tip" or "tip side," and the side that is operated by the user will be referred to as the "proximal end" or "proximal end."

[0026] The medical device in the following embodiment is configured to expand a first through-hole Hh formed in the atrial septum HA of the patient's heart H into a second through-hole Hh2, and then to maintain the expanded second through-hole Hh2 at its size through a maintenance procedure to create a communication hole Hh.

[0027] As shown in Figure 1, the medical device 10 of this embodiment has a hollow, elongated shaft 20, an extension body 21 which is an electrode support provided at the tip of the shaft 20, and a handheld operating part 23 provided at the base end of the shaft 20. The extension body 21 supports an electrode assembly 22 which includes an electrode part 70 which is an energy transfer element for performing the aforementioned maintenance procedure.

[0028] The shaft 20 is joined to the base end of the expansion body 21 and has a hollow tip extension 30 at its tip that extends inward from the base end of the expansion body 21. The tip extension 30 extends along the central axis of the expansion body 21 from near the base end of the expansion body 21 to partway along the expansion body 21, specifically to the vicinity of the recess 51 of the expansion body 21. The shaft 20 also has a connecting portion 28 that is connected to the base end of the expansion body 21.

[0029] A storage sheath 25 is provided on the outer circumference of the shaft 20. The shaft 20 is movable axially relative to the storage sheath 25. When the storage sheath 25 is moved toward the tip of the shaft 20, the expansion body 21 can be housed inside it. By moving the storage sheath 25 toward the base end from the state in which the expansion body 21 is housed, the expansion body 21 can be exposed.

[0030] Inside the shaft 20, a traction shaft 26 is slidably positioned relative to the shaft 20. The traction shaft 26 extends from the base end of the hand-operated section 23 to the tip end of the extension body 21. The traction shaft 26 protrudes from the tip of the shaft 20, specifically from the tip extension 30, passes inside the extension body 21, and protrudes from the tip of the extension body 21. The tip of the traction shaft 26 is fixed to the tip member 36.

[0031] The tip member 36 to which the tip of the traction shaft 26 is fixed does not need to be fixed to the expansion body 21. This allows the tip member 36 to exert a compressive force on the expansion body 21 along the axis of the shaft 20 as the traction shaft 26 slides relative to the shaft 20 in the base direction. Furthermore, when storing the expansion body 21 in the storage sheath 25, moving the tip member 36 away from the expansion body 21 towards the tip makes it easier for the expansion body 21 to move in the extension direction, thereby improving storage efficiency.

[0032] The handheld control unit 23 includes a housing 40 that is grasped by the operator, an operating dial 41 that can be rotated by the operator, and a conversion mechanism 42 that operates in conjunction with the rotation of the operating dial 41. The traction shaft 26 is held by the conversion mechanism 42 inside the handheld control unit 23. The conversion mechanism 42 can move the traction shaft 26 it holds forward and backward along the axial direction as the operating dial 41 rotates. For example, a rack and pinion mechanism can be used as the conversion mechanism 42.

[0033] The shaft 20 is preferably formed from 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 mixtures of two or more of these; flexible polyvinyl chloride resin, polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane, fluororesin such as polytetrafluoroethylene, polyimide, PEEK, silicone rubber, latex rubber, and the like.

[0034] The traction shaft 26 can be formed from, for example, a superelastic alloy such as a nickel-titanium alloy or a copper-zinc alloy, a metallic material such as stainless steel, or a relatively rigid resin material.

[0035] The tip member 36 can be formed from, for example, a superelastic alloy such as nickel-titanium alloy or copper-zinc alloy, a metallic material such as stainless steel, a polymer material such as polyolefin, polyvinyl chloride, polyamide, polyamide elastomer, polyurethane, polyurethane elastomer, polyimide, fluororesin, or a mixture thereof, or a multilayer tube made of two or more polymer materials.

[0036] As shown in Figures 2 and 3, the expandable body 21 has a plurality of linear bodies 50 in the circumferential direction. The linear bodies 50 branch and merge along the length direction between the connecting portion 28 to which the base end is connected and the tip converging portion 57 to which the tip is connected, thereby forming a mesh-like structure. As a result, the expandable body 21 can be expanded and contracted in the radial direction. The distance between adjacent linear bodies 50 in the circumferential direction among the plurality of linear bodies 50 constituting the expandable body 21 changes according to the expansion and contraction of the expandable body 21. The base end of the linear body 50 extends from the connecting portion 28 of the expandable body 21 toward the tip. The tip of the linear body 50 extends from the tip converging portion 57 of the expandable body 21 toward the base end. When the expandable body 21 is expanded, the linear body 50 has a base-side inclined portion 58 that expands in diameter from the base-side connecting portion 28 toward the base-side apex 54. Furthermore, the linear body 50 has a tip-side inclined portion 59 that widens in diameter from the tip-converging portion 57 toward the tip-side apex portion 55. The linear body 50 has a recess 51 in the axial center that is recessed radially inward of the expandable body 21. The innermost radial portion of the recess 51 is the bottom portion 51a. The recess 51 defines a receptive space 51b capable of receiving biological tissue when the expandable body 21 expands.

[0037] The recess 51 has a proximal upright portion 52 that extends radially outward from the proximal end of the bottom portion 51a to the proximal top portion 54, and a distal upright portion 53 that extends radially outward from the distal end of the bottom portion 51a. When the traction shaft 26 slides in the proximal direction relative to the shaft 20 and a compressive force is applied to the expandable body 21, the distal upright portion 53 and the proximal upright portion 52 move closer to each other and come into close contact with the biological tissue received in the receiving space 51b. An electrode portion 70 is arranged along the recess 51 on the proximal upright portion 52 so as to face the receiving space 51b. That is, the electrode portion 70 is provided in the middle of the central axis direction of the expandable body 21 so as to be exposed to the outside of the expandable body 21 along the expandable body 21. In this embodiment, 10 electrode portions 70 are provided along the circumferential direction. However, the number of electrode portions 70 is not limited. Note that the electrode portion 70 may also be arranged on the distal upright portion 53.

[0038] The linear body 50 forming the extended body 21 can be formed by laser cutting or the like from a single metal cylindrical member. The linear body 50 can be formed from a metallic material. Examples of this metallic material 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 an alloy with spring properties such as nickel-titanium alloy. However, the material of the linear body 50 is not limited to these and may be formed from other materials.

[0039] The electrode unit 70 is connected to an external device, an energy supply device (not shown). A high-frequency voltage is applied from the energy supply device to the electrode pair consisting of the two electrode units 70, and energy is supplied between them. In other words, the electrode unit 70 is configured as a bipolar electrode. Note that the electrode unit 70 may also be a monopolar electrode. In this case, current is supplied between it and an external electrode.

[0040] An electrode assembly 22, separate from the extension 21, is attached to the extension 21. As shown in Figure 2, the electrode assembly 22 has a long wiring section 71 and an electrode section 70 provided at the tip of the wiring section 71. The electrode section 70 has an exposed conductive surface. The wiring section 71 has a surface covered with an insulating layer.

[0041] As shown in Figure 4, the shaft 20 has a shaft body 60 that extends in the axial direction and an outer layer 65 that covers the outside of the shaft body 60. A conductor portion 80 that is electrically connected to the electrode assembly 22 is arranged between the shaft body 60 and the outer layer 65.

[0042] The conductor portion 80 is connected to the electrode assembly 22 at the contact portion 85 at its tip. Multiple wiring portions 71 are integrated at their base ends by a circumferentially extending aggregation portion 72. Extending from the aggregation portion 72 towards the base end are a first electrode-side conductor portion 74 through which one of the electrode portions 70 of the multiple electrode portions 70 conducts, and a second electrode-side conductor portion 75 through which the electrode portion 70 of the other of the multiple electrode portions 70 conducts. The conductor portion 80 has a first conductor portion 81 connected to the first electrode-side conductor portion 74 at the first contact portion 86 of the contact portion 85, and a second conductor portion 82 connected to the second electrode-side conductor portion 75 at the second contact portion 87 of the contact portion 85. Furthermore, if the electrode section 70 is configured to have multiple electrode sections as a monopolar electrode, the electrode section 70 is electrically connected to one electrode-side conductor section extending from the aggregation section 72, which is formed by integrating the base ends of multiple wiring sections 71, toward the base end. In this case, the conductor section 80 consists of one conductor section that is connected to one electrode-side conductor section at one contact section 85.

[0043] The first conductor section 81 and the second conductor section 82 are each wound around the outer circumferential surface of the shaft body 60. The first conductor section 81 and the second conductor section 82 are wound around the shaft body 60 circumferentially, spaced 180° apart from each other. Therefore, the first conductor section 81 and the second conductor section 82 are arranged alternately in a spiral pattern along the axial direction of the shaft body 60. The axial distance between two axially adjacent first conductor sections 81 and second conductor sections 82 is 1.0 to 2.0 times the diameter of the shaft body 60. Specifically, the axial distance between two axially adjacent first conductor sections 81 and second conductor sections 82 is 3 mm to 6 mm.

[0044] The outer layer 65 covers up to the axial middle position of the first electrode-side conductor portion 74, the second electrode-side conductor portion 75, and the wiring portion 71 among the conductor portion 80, contact portion 85, and electrode assembly 22 arranged on the outside of the shaft body 60. In the shaft body 60, the portion on the distal end side relative to the distal end of the outer layer 65 is the aforementioned distal extension 30.

[0045] In the wiring portion 71, the portion on the distal end side relative to the distal end of the outer layer 65 is exposed to the outside of the shaft 20. As shown in FIG. 5, in the wiring portion 71, the portion on the distal end side relative to the distal end of the outer layer 65 is separated from the shaft 20 inside the expandable body 21, extends toward the recess 51 of the linear body 50, and penetrates the linear body 50. Thereby, the electrode portion 70 provided at the distal end of the wiring portion 71 is disposed on the proximal standing portion 52 and exposed toward the outside of the expandable body 21.

[0046] As shown in FIG. 4, the shaft body 60 includes a first shaft body portion 61 on the proximal end side, and a second shaft body portion 62 on the distal end side joined to the first shaft body portion 61 at a shaft joint 63 at the distal end of the first shaft body portion 61. The first shaft body portion 61 extends from the proximal end of the shaft body 60 located at the manual operation portion 23 to the shaft joint 63. The second shaft body portion 62 extends from the shaft joint 63 to the distal end of the shaft body 60, that is, the distal end of the distal extension 30.

[0047] The second shaft body portion 62 has lower rigidity than the first shaft body portion 61. Therefore, the distal end portion of the shaft body 60 is easily bent or curved. On the other hand, since the first shaft body portion 61 has higher rigidity than the second shaft body portion 62, the rigidity required for inserting the shaft body 60 from a blood vessel to the heart can be ensured.

[0048] The outer layer 65 includes a proximal first outer layer 66 and a distal second outer layer 67 joined at an outer layer joint 68 at the distal end of the first outer layer 66. The first outer layer 66 extends from the proximal end of the shaft body 60 to the outer layer joint 68. The second outer layer 67 extends from the outer layer joint 68 to the distal end of the outer layer 65, which is located proximally relative to the distal end of the shaft body 60. The proximal end of the first outer layer 66 is located within the proximal operation section 23 and on the distal side relative to the proximal end of the shaft body 60. A portion of the conductive wire portion 80 extending proximally from the proximal end of the first outer layer 66 is exposed to the outside of the shaft body 60. The portion of the conductive wire portion 80 exposed on the proximal end side of the shaft body is connected to an energy supply device.

[0049] A contact portion 85 connecting the wiring portion 71 and the conductive wire portion 80 is disposed between the second shaft body portion 62 and the second outer layer 67. That is, both the first contact portion 86 and the second contact portion 87 of the contact portion 85 are covered by the second outer layer 67.

[0050] The outer layer joint 68 is disposed at a position different from that of the shaft joint 63 in the axial direction of the shaft 20. In the present embodiment, the outer layer joint 68 is located on the distal side relative to the shaft joint 63. However, the outer layer joint 68 may alternatively be located on the proximal side relative to the shaft joint 63.

[0051] Since the shaft joint 63 and the outer layer joint 68 are each portions where different members are joined, their tensile strength is lower than that of other portions. By disposing the shaft joint 63 and the outer layer joint 68 at different positions in the axial direction of the shaft 20, a reduction in the strength of the shaft 20 can be suppressed.

[0052] As shown in FIG. 6, the shaft 20 has a bent portion 33 (or curved portion) shaped at the distal end portion close to the expandable body 21. By having the bent portion 33, the shaft 20 can facilitate orienting the expandable body 21 toward the atrial septum within the heart. Note that the bent portion 33 may be a curved portion. The bent portion 33 is located on the shaft 20 on the distal side relative to the shaft joint 63 and the outer layer joint 68, and on the proximal side relative to the contact portion 85. Therefore, none of the shaft joint 63, the outer layer joint 68, nor the contact portion 85 is located at the bent portion 33.

[0053] Next, the manufacturing method of the shaft 20 will be described. As shown in Figure 7(a), first, a first shaft body portion 61 and a second shaft body portion 62 are prepared and joined together along the axial direction. This forms a shaft body 60 having a shaft joint portion 63. The first shaft body portion 61 and the second shaft body portion 62 can be joined by heating and fusing them together.

[0054] Next, the conductor portion 80 is wound around the shaft body 60. As shown in Figure 7(b), the conductor portion 80 is wound so that the first conductor portion 81 and the second conductor portion 82 are adjacent to each other along the axial direction of the shaft body 60. At this point, the conductor portion 80 is wound around the base end region 60a of the shaft body 60, from the base end to just before the tip region 60b. Therefore, at this point, the conductor portion 80 is not wound around the tip region 60b of the shaft body 60. The shaft joint portion 63, where the first shaft body portion 61 and the second shaft body portion 62 are joined, is included in the base end region 60a. Therefore, the conductor portion 80 is wound around the shaft body 60 from the shaft joint portion 63 towards the tip.

[0055] Next, as shown in Figure 7(c), the base end region 60a of the shaft body 60 is covered with the first outer layer 66. The first outer layer 66 is provided so as to cover the outside of the base end region 60a, including the conductor portion 80 that is placed on the base end region 60a. The outer layer 65 is made of a thermoplastic resin, and by covering the base end region 60a of the shaft body 60 with the first outer layer 66 and heating it, the first outer layer 66 shrinks radially and is fixed to the shaft body 60. As a result, the wound conductor portion 80 is positioned between the shaft body 60 and the first outer layer 66 in the base end region 60a of the shaft body 60. The shaft joint portion 63 of the shaft body 60 is covered with the first outer layer 66.

[0056] At this point, the conductor portion 80 is exposed beyond the tip of the first outer layer 66. As shown in Figure 8, the first outer layer 66 has a reduced diameter portion 66a where the outer diameter of the tip portion decreases towards the tip.

[0057] Next, as shown in Figure 7(d), the conductor portion 80 exposed on the tip side of the first outer layer 66 is connected to the electrode assembly 22 to form a contact portion 85. Before being attached to the shaft body 60, the electrode assembly 22 has a linear aggregation portion 72 from which a plurality of wiring portions 71 extend toward the tip side, and electrode portions 70 are provided at the tips of the wiring portions 71. A first electrode-side conductor portion 74 and a second electrode-side conductor portion 75 are drawn out from the aggregation portion 72, and the first conductor portion 81 is connected to the first electrode-side conductor portion 74 to form a first contact portion 86, and the second conductor portion 82 is connected to the second electrode-side conductor portion 75 to form a second contact portion 87.

[0058] Next, as shown in Figure 7(e), the conductor portion 80 exposed towards the tip from the first outer layer 66 is wound around the tip region 60b of the shaft body 60. The conductor portion 80 in the tip region 60b is wound at the same pitch as the conductor portion 80 in the base region 60a. The electrode assembly 22 is arranged so that the wiring portion 71 and the electrode portion 70 are aligned circumferentially at the tip of the shaft body 60. Note that the conductor portion 80 may be wound up to the tip region 60b of the shaft body 60 before forming the contact portion 85, i.e., at the stage shown in Figure 7(c).

[0059] Next, as shown in Figure 7(f), a second outer layer 67 is provided so as to cover the outside of the tip region 60b of the shaft body 60, including the conductor portion 80 and contact portion 85 wound around the tip region 60b of the shaft body 60. As shown in Figure 9(a), the base end of the second outer layer 67 is positioned to overlap the reduced diameter portion 66a of the first outer layer 66 from the outer circumference. By heating the second outer layer 67 and shrinking it radially, as shown in Figure 9(b), the first outer layer 66 and the second outer layer 67 are joined together, forming an outer layer 65 having an outer layer joint portion 68. Since the first outer layer 66 has a reduced diameter portion 66a at its tip and the base end of the second outer layer 67 overlaps the reduced diameter portion 66a, it is possible to make it less likely for a step to occur at the outer layer joint portion 68 when the first outer layer 66 and the second outer layer 67 are joined together.

[0060] In this way, the outer layer joint 68 is formed by joining the second outer layer 67 to the tip side of the first outer layer 66, which is provided from the shaft joint 63 to the tip side. Therefore, in the outer layer 65, the outer layer joint 68 is positioned at a different location from the shaft joint 63 in the axial direction of the shaft 20. By positioning the outer layer joint 68 on the tip side of the shaft 20 from the shaft joint 63, the winding work of the conductor portion 80 with respect to the tip region 60b shown in Figure 7(e) can be reduced, and the manufacturing of the shaft 20 can be made easier.

[0061] Once the second outer layer 67 is provided to form the outer layer 65, the expansion body 21 is attached to the tip of the shaft 20, the wiring portion 71 exposed on the tip side of the outer layer 65 is attached to the expansion body 21, and the electrode portion 70 is positioned on the expansion body 21.

[0062] Next, a bent portion 33 is formed at the tip of the shaft 20. As shown in Figure 10, the bent portion 33 is formed by shaping the shaft 20 by clamping it with a bending jig 200. The shaft 20 is formed by clamping the portion of the shaft 20 that is closer to the tip than the shaft joint portion 63 and the outer layer joint portion 68, and closer to the base end than the contact portion 85, with the bending jig 200. Therefore, when the bent portion 33 is formed, the shaft joint portion 63, the outer layer joint portion 68, and the contact portion 85 are not clamped by the bending jig 200, and thus are not affected.

[0063] Next, the method of using the medical device 10 will be described. When using the medical device 10, a first through-hole Hh1 is formed in advance at the fossa ovale of the atrial septum HA. The medical device 10 expands and widens this first through-hole Hh1 to form a substantially circular second through-hole Hh2, and cauterizes the edge of the second through-hole Hh2. In this way, the medical device 10 forms a communication hole Hh that maintains its size, i.e., patency. As shown in Figure 11, the medical device 10 is delivered from the inferior vena cava IV through the right atrium HRa to the vicinity of the atrial septum HA, and the expander 21 is positioned at the location of the pre-formed first through-hole Hh1. The tip of the medical device 10 is positioned so as to penetrate the atrial septum HA and reach the left atrium HLa. At this time, the shaft 20 has a bent portion 33 at its tip, which makes it easier to position the expander 21 at the location of the first through-hole Hh1.

[0064] When inserting the medical device 10, the expander 21 is retracted and stored in the storage sheath 25. The expander 21 can be exposed by moving the storage sheath 25 towards the proximal end from the state in which the storage sheath 25 has penetrated the atrial septum HA. When the expander 21 is exposed, it expands radially, and the recess 51 is positioned in the first through-hole Hh1 of the atrial septum HA, receiving the biological tissue surrounding the first through-hole Hh1 in the receiving space 51b.

[0065] As shown in Figure 12, when the traction shaft 26 is moved towards the proximal end while the receiving space 51b is receiving biological tissue, the expander 21 is pulled in the compression direction by the tip member 36 and compressed axially. As a result, the atrial septum HA is grasped by the proximal upright portion 52 and the tip upright portion 53 that form the recess 51, and the electrode portion 70 is pressed against the biological tissue. At this time, as the radial position of the recess 51 moves outward, the first through-hole Hh1 is expanded radially, and the second through-hole Hh2 is formed. The diameter of the second through-hole Hh2 is larger than that of the first through-hole Hh1. The fossa ovale, where the second through-hole Hh2 is formed, has less wall thickness than other parts of the atrial septum HA. Therefore, the recess 51 of the expander 21 can sandwich the biological tissue surrounding the second through-hole Hh2 so as to press the electrode portion 70 against the biological tissue.

[0066] With the electrode portion 70 pressed against the biological tissue, high-frequency energy can be applied through the electrode portion 70 to the edge of the second through-hole Hh2, that is, to the biological tissue surrounding the second through-hole Hh2, thereby cauterizing (heating and cauterizing) the edge of the second through-hole Hh2 with high-frequency energy. The high-frequency energy is applied by applying a voltage between a pair of circumferentially adjacent electrode portions 70. This prevents the communication hole Hh from closing due to natural healing and maintains its size. After cauterization, when the expander 21 is contracted and removed, the second through-hole Hh2 contracts slightly in the radial direction, and a communication hole Hh is formed.

[0067] When using the medical device 10, hemodynamic monitoring is performed by a hemodynamic monitoring device 120 delivered to the right atrium HRa via the inferior vena cava IV. For example, a known echocardiogram catheter can be used as the hemodynamic monitoring device 120. The operator can display the echocardiogram acquired by the hemodynamic monitoring device 120 on a display device such as a display, and confirm the amount of blood passing through the communication opening Hh based on the display results.

[0068] When removing the expander 21 after cauterization by the electrode 70, the storage sheath 25 is advanced relative to the shaft 20, and the expander 21 is pulled into the storage sheath 25 from the proximal end.

[0069] As described above, the (1) medical device 10 according to this embodiment includes an electrode support (extension 21) that supports an electrode assembly 22 including an electrode portion 70 for applying energy to biological tissue, and a shaft 20 joined to the base end of the electrode support (extension 21). The shaft 20 includes a shaft body 60 extending in the axial direction, an outer layer 65 covering the outside of the shaft body 60, and a conductor portion 80 sandwiched between the shaft body 60 and the outer layer 65 and electrically connected to the electrode assembly 22 at a contact portion 85. The medical device 10 has a first shaft body portion 61 extending from the base end to the tip end, and a second shaft body portion 62 joined at the shaft joint portion 63 at the tip of the first shaft body portion 61. The outer layer 65 has a first outer layer 66 extending from the base end to the tip end of the first shaft body portion 61, and a second outer layer 67 joined at the outer layer joint portion 68 at the tip of the first outer layer 66. The contact portion 85 is positioned between the second shaft body portion 62 and the second outer layer 67, and the shaft joint portion 63 and the outer layer joint portion 68 are positioned at different locations in the axial direction of the shaft 20. In this configuration, the medical device 10 has a shaft body 60 covered with an outer layer 65, and because the shaft joint portion 63 and the outer layer joint portion 68, which are areas of lower strength, are positioned at different locations in the axial direction of the shaft 20, a decrease in strength can be suppressed even if the shaft body 60 is covered with an outer layer 65 and has a shaft joint portion 63 and an outer layer joint portion 68.

[0070] (2) In the medical device 10 described in (1) above, the outer layer joint portion 68 may be positioned on the tip side of the shaft joint portion 63. This makes it possible to shorten the length of the conductor portion 80 that is sandwiched between the tip of the shaft body 60 after it has been covered with the first outer layer 66 and the second outer layer 67 when manufacturing the shaft 20 of the medical device 10, thereby making manufacturing easier.

[0071] (3) In the medical device 10 described in (1) or (2) above, the conductor portion 80 may be wound around the outer circumference of the shaft body 60 and sandwiched between the shaft body 60 and the outer layer 65. This makes it possible for the medical device 10 to maintain a constant bending characteristic of the shaft 20 along the axial direction, and to facilitate insertion of the shaft 20 into a blood vessel.

[0072] (4) In any of the medical devices 10 described in (1) to (3) above, the conductor portion 80 has a first conductor portion 81 and a second conductor portion 82, and the first conductor portion 81 and the second conductor portion 82 may be wound around the shaft body 60 at a distance of 180° from each other in the circumferential direction. This makes it difficult for the conductor portion 80 to break when the shaft 20 is bent, and also makes it possible to suppress the influence of the current flowing through the first conductor portion 81 and the second conductor portion 82 on the current of the other.

[0073] (5) In the medical device 10 described in (4) above, the conductor portion 80 may be wound around the shaft body 60 such that the distance along the axial direction between two axially adjacent conductor portions, the first conductor portion 81 and the second conductor portion 82, is 1.0 to 2.0 times the diameter of the shaft body 60. In order to suppress breakage of the conductor portion 80 due to the curvature of the shaft 20, a narrower winding pitch is advantageous. However, if the winding pitch is narrow, the influence of the current flowing through each adjacent conductor portion 80 on the other increases, and the conductor portion 80 becomes longer, resulting in greater voltage loss. By setting the distance along the axial direction between two axially adjacent conductor portions 80 to 1.0 to 2.0 times the diameter of the shaft body 60, it is possible to suppress breakage of the conductor portion 80 due to the curvature of the shaft 20 and suppress the influence between currents and voltage loss at the same time.

[0074] (6) In any of the medical devices 10 described in (1) to (5) above, the second shaft body portion 62 may have lower rigidity than the first shaft body portion 61. This makes it easier to bend the tip of the shaft 20 of the medical device 10, making it easier to position the electrode support (extension 21) at the target site.

[0075] (7) In any of the medical devices 10 described in (1) to (6) above, the shaft 20 may have a curved portion or bent portion 33 at a position that is tipward from the shaft joint portion 63 and the outer layer joint portion 68, and proximal to the contact portion 85. This allows the medical device 10 to be configured such that the curved portion or bent portion 33 of the shaft 20 does not affect the shaft joint portion 63, the outer layer joint portion 68, and the contact portion 85.

[0076] The method for manufacturing the medical device 10 according to this embodiment (8) comprises an electrode support (extension 21) that supports an electrode assembly 22 including an electrode portion 70 for applying energy to biological tissue, and a shaft 20 joined to the base end of the electrode support (extension 21), wherein the shaft 20 comprises a shaft body 60 extending in the axial direction, an outer layer 65 covering the outside of the shaft body 60, and a conductor portion 80 sandwiched between the shaft body 60 and the outer layer 65 and electrically connected to the electrode assembly 22 at a contact portion 85, and the method for manufacturing the medical device 10 comprises the steps of joining a second shaft body portion 62 in the axial direction to the tip of a first shaft body portion 61 to form a shaft body 60 having a shaft joint portion 63, and the shaft The manufacturing method for the medical device 10 includes the steps of: placing the conductor portion 80 on the base end region 60a of the shaft body 60 from the base end to just before the tip region 60b; providing a first outer layer 66 so as to cover the outside of the base end region 60a of the shaft body 60, including the conductor portion 80 placed on the base end region 60a of the shaft body 60; electrically connecting the conductor portion 80 exposed towards the tip from the first outer layer 66 to the electrode assembly 22 to form a contact portion 85; and providing a second outer layer 67 so as to cover the outside of the tip region 60b of the shaft body 60, including the conductor portion 80 and the contact portion 85 exposed towards the tip from the first outer layer 66, and joining it with the first outer layer 66 to form an outer layer 65 having an outer layer joint portion 68 that is in a different axial position from the shaft joint portion 63. The manufacturing method for the medical device 10 configured in this way can manufacture a medical device 10 having a shaft 20 in which the shaft joint portion 63 and the outer layer joint portion 68, which have reduced strength, are positioned at different positions in the axial direction of the shaft 20.

[0077] (9) In the method for manufacturing the medical device 10 described in (8) above, when providing the first outer layer 66, a reduced diameter portion 66a may be formed at the tip of the first outer layer 66, and when providing the second outer layer 67, the base end of the second outer layer 67 may be positioned to overlap with the reduced diameter portion 66a. This makes it less likely for a step to occur at the outer layer joint portion 68 in the method for manufacturing the medical device 10.

[0078] (10) In the method for manufacturing the medical device 10 described in (8) or (9) above, the second shaft body portion 62 may have lower rigidity than the first shaft body portion 61. This makes it possible to manufacture a medical device 10 in which the tip portion of the shaft 20 having the electrode support (extension 21) is easily bent.

[0079] (11) In any of the manufacturing methods of the medical device 10 described in (8) to (10) above, the conductor portion 80 may be wound around the base end region 60a of the shaft body 60, and a first outer layer 66 may be provided so as to cover the outside of the base end region 60a of the shaft body 60, including the conductor portion 80 wound around the base end region 60a. This ensures that the conductor portion 80 is wound around the base end region 60a of the shaft body 60, thereby suppressing breakage of the conductor portion 80 due to bending of the shaft 20.

[0080] (12) In any of the methods for manufacturing a medical device described in (8) to (11) above, the conductor portion exposed on the tip side of the first outer layer may be wound around the tip region of the shaft body, and a second outer layer may be provided so as to cover the outside of the tip region of the shaft body, including the conductor portion and the contact portion wound around the tip region. As a result, the conductor portion 80 is arranged in a wound state in the tip region 60b of the shaft body 60, and breakage of the conductor portion 80 due to bending of the shaft 20 can be suppressed.

[0081] (13) In any of the methods for manufacturing the medical device 10 described in (8) to (12) above, the method may further include the step of bending or flexing the shaft 20 at a position that is closer to the tip than the shaft joint 63 and the outer layer joint 68, and closer to the base than the contact portion 85, with the conductor portion 80 and the contact portion 85, which are wound around the tip region 60b of the shaft body 60, sandwiched between the shaft body 60 and the outer layer 65. This makes it possible to form a curved portion or a bent portion 33 at the tip of the shaft 20 without affecting the shaft joint 63, the outer layer joint 68, and the contact portion 85.

[0082] It should be noted that the present invention is not limited to the embodiments described above, and various modifications can be made by those skilled in the art within the technical framework of the present invention. In the embodiments described above, the electrode support portion is an expandable body 21 that can expand and contract in the radial direction, but any structure capable of supporting the electrode assembly 22 is acceptable, and it may not expand or contract in the radial direction. Also, the conductor portion 80 may not be wound around the outer circumferential surface of the shaft body 60, but rather sandwiched between the shaft body 60 and the outer layer 65. Furthermore, the conductor portion 80 exposed towards the tip from the first outer layer 66 may be wound or otherwise positioned in the tip region 60a of the shaft body 60, and then electrically connected to the electrode assembly 22 to form a contact portion 85.

[0083] This application is based on Japanese Patent Application No. 2025-56103, filed on March 28, 2025, and its disclosures are referenced and incorporated as a whole.

[0084] 10 Medical device 20 Shaft 21 Extension (electrode support) 22 Electrode assembly 26 Traction shaft (traction part) 30 Tip extension 33 Bent part (curved part) 36 Tip member 50 Wire 51 Recess 60 Shaft body 60a Base region 60b Tip region 61 First shaft body 62 Second shaft body 63 Shaft joint 65 Outer layer 66 First outer layer 66a Reduced diameter section 67 Second outer layer 68 Outer layer joint 70 Electrode section 71 Wiring section 72 Convergence section 74 First electrode-side conductor section 75 Second electrode-side conductor section 80 Conductor section 81 First conductor section 82 Second conductor section 85 Contact section 86 First contact section 87 Second contact section

Claims

1. A medical device comprising: an electrode support for supporting an electrode assembly including an electrode portion for applying energy to biological tissue; and a shaft joined to the base end of the electrode support, wherein the shaft comprises: a shaft body extending in the axial direction; an outer layer covering the outside of the shaft body; and a conductor portion sandwiched between the shaft body and the outer layer and electrically connected to the electrode assembly at a contact portion, wherein the shaft body comprises: a first shaft body portion extending from the base end to the tip side; and a second shaft body portion joined at a shaft joint portion at the tip of the first shaft body portion, wherein the outer layer comprises: a first outer layer extending from the base end to the tip side of the first shaft body portion; and a second outer layer joined at an outer layer joint portion at the tip of the first outer layer, wherein the contact portion is located between the second shaft body portion and the second outer layer, and the shaft joint portion and the outer layer joint portion are located at different positions in the axial direction of the shaft.

2. The medical device according to claim 1, wherein the outer layer joint is positioned on the tip side of the shaft joint.

3. The medical device according to claim 1, wherein the conductor portion is wound around the outer circumferential surface of the shaft body and is sandwiched between the shaft body and the outer layer.

4. The medical device according to claim 3, wherein the conductor portion has a first conductor portion and a second conductor portion, and the first conductor portion and the second conductor portion are wound around the shaft body at a distance of 180° from each other in the circumferential direction.

5. The medical device according to claim 4, wherein the conductor portion is wound around the shaft body such that the distance along the axial direction between two axially adjacent conductor portions between the first conductor portion and the second conductor portion is 1.0 to 2.0 times the diameter of the shaft body.

6. The medical device according to claim 1, wherein the second shaft body has lower rigidity than the first shaft body.

7. The medical device according to claim 1 or 6, wherein the shaft has a curved portion or bent portion at a position toward the tip of the shaft joint and the outer layer joint, and toward the base end of the contact portion.

8. A method for manufacturing a medical device comprising: an electrode support for supporting an electrode assembly including an electrode portion for applying energy to biological tissue; a shaft joined to the base end of the electrode support, wherein the shaft comprises: a shaft body extending in the axial direction; an outer layer covering the outside of the shaft body; and a conductor portion sandwiched between the shaft body and the outer layer and electrically connected to the electrode assembly at a contact portion, the method comprising: joining a second shaft body portion in the axial direction to the tip of a first shaft body portion to form the shaft body having a shaft joint portion; arranging the conductor portion on the base end region of the shaft body from the base end to just before the tip region; providing a first outer layer so as to cover the outside of the base end region of the shaft body, including the conductor portion arranged on the base end region of the shaft body; and electrically connecting the conductor portion exposed on the tip side of the first outer layer to the electrode assembly to form the contact portion. A method for manufacturing a medical device, comprising the steps of: providing a second outer layer so as to cover the outside of the tip region of the shaft body, including the conductor portion and the contact portion exposed towards the tip from the first outer layer, and joining it with the first outer layer to form an outer layer having an outer layer joint portion that is in an axial position different from the shaft joint portion.

9. The method for manufacturing a medical device according to claim 8, wherein when providing the first outer layer, a reduced diameter portion is formed at the tip of the first outer layer, and when providing the second outer layer, the base end of the second outer layer is positioned to overlap with the reduced diameter portion.

10. The medical device according to claim 8 or 9, wherein the second shaft body has lower rigidity than the first shaft body.

11. The medical device according to claim 8 or 9, wherein the conductor portion is wound around the base end region of the shaft body, and a first outer layer is provided so as to cover the outside of the base end region of the shaft body, including the conductor portion wound around the base end region.

12. The medical device according to claim 8 or 9, wherein the conductor portion exposed on the tip side of the first outer layer is wound around the tip region of the shaft body, and a second outer layer is provided so as to cover the outside of the tip region of the shaft body, including the conductor portion and the contact portion wound around the tip region.

13. A method for manufacturing a medical device according to claim 8 or 9, further comprising the step of bending or flexing the shaft at a position that is closer to the tip than the shaft joint and the outer layer joint, and closer to the base than the contact portion, with the conductor portion and the contact portion, which are arranged in the tip region of the shaft body, sandwiched between the shaft body and the outer layer.

Images