Medical device

Abstract

To provide a medical device that is capable of, at a contact portion of an electrode portion and an electrical lead, preventing short-circuiting with another contact portion that is electrically independent. A medical device 10 includes an expanding member 21 that is capable of being expanded / reduced in the radial direction, a slender shaft portion 20 that includes a basal end fixing portion 31 to which a basal end of the enlarging member 21 is fixed, a plurality of electrode assemblies 60 including a plurality of electrode portions 22 disposed along the enlarging member 21, and electrical lead portions 66 that are disposed within the shaft portion 20 and that are connected to the electrode assemblies 60 at contact portions 62. At least two or more of the plurality of electrode assemblies 60 are electrically independent. Two or more contact portions 62 to which two or more electrode assemblies 60 that are electrically independent each are connected are disposed at different positions in the axial direction within the shaft portion 20.

Description

Technical Field

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

Background Art

[0002] As a medical device, there is known one that performs ablation treatment for cauterizing biological tissue with a high-frequency current from an electrode portion disposed on an expander that expands and contracts in vivo. As one of the ablation treatments, shunt treatment for the atrial septum is known. Shunt treatment forms a shunt (puncture hole), which serves as an escape route for the elevated atrial pressure, in the fossa ovalis of the atrial septum for patients with heart failure, enabling alleviation of heart failure symptoms. In shunt treatment, access to the atrial septum is achieved by a transvenous approach to form a shunt of a desired size.

[0003] The electrode portion of the expander is connected to a conducting wire provided along the shaft portion and can receive energy supply from an energy application device provided on the hand side. Such a medical device is disclosed, for example, in Patent Document 1.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a medical device, when the electrode part is a bipolar electrode or a multi-polar electrode part, if the conducting wires to which the electrode parts are connected are short-circuited in the shaft part, it may cause risks such as heat generation at unintended sites and electric leakage, and it may also be impossible to obtain the intended potential data. In particular, when the contact part between the electrode part and the conducting wire is provided inside the shaft part, when the shaft part is bent under an external force during the assembly or use of the medical device, there is a possibility that the contact parts of different poles that are electrically independent of each other may be short-circuited.

[0006] The present invention has been made to solve the above-described problems, and an object thereof is to provide a medical device capable of preventing a short circuit between the contact part between the electrode part and the conducting wire and other contact parts that are electrically independent.

Means for Solving the Problems

[0007] The medical device according to the present invention that achieves the above object includes an expandable body that can expand and contract in the radial direction, a long shaft part having a proximal end fixing part to which the proximal end of the expandable body is fixed at the distal end, a plurality of electrode assemblies including a plurality of electrode parts arranged along the expandable body, and a conducting wire part arranged in the shaft part and connected to the electrode assembly at a contact part. The plurality of electrode assemblies have at least two or more that are electrically independent, and the two or more contact parts to which the two or more electrically independent electrode assemblies are respectively connected are arranged at different positions in the axial direction within the shaft part.

Effects of the Invention

[0008] In the medical device configured as described above, when the shaft part is bent under an external force during the assembly or use of the medical device, since the contact parts that are electrically independent of each other are separated in the axial direction, it is possible to prevent them from coming into contact and short-circuiting.

[0009] A voltage may be applied between electrode pairs formed by electrode portions included in at least two of the two or more electrically independent electrode assemblies. Thereby, when the electrode portion is configured as a bipolar electrode, it is possible to prevent the electrode portions constituting the electrode pair from short-circuiting at the contact portion.

[0010] A plurality of the electrode pairs may be provided, and all the contact portions to which the electrode assemblies are connected may be arranged at different axial positions within the shaft portion. Thereby, when a plurality of electrode pairs are provided, it is possible to prevent any electrode portion from short-circuiting with other electrode portions.

[0011] The electrode assembly may include an electrode portion arranged along the extension body and having a conductive surface, an insulating portion arranged on the proximal end side of the electrode portion and having an insulated surface, and a contact portion arranged on the proximal end side of the insulating portion. Thereby, since the region of the electrode assembly arranged within the shaft portion does not short-circuit except at the contact portion, by making the axial positions of the contact portions different, short-circuiting between the electrode portions can be reliably prevented.

[0012] The shaft portion may include an inner layer having a lumen and an outer layer provided on the radially outer side of the inner layer, and the contact portion may be arranged between the inner layer and the outer layer. Thereby, current leakage can be reliably prevented.

[0013] The shaft portion may have a bent portion that bends in one direction toward the proximal end starting from the proximal end fixing portion or a position on the proximal end side of the proximal end fixing portion, and the contact portion may be arranged on the proximal end side of the bent portion. Thereby, the axial direction of the extension body can be arranged to be close to perpendicular to the plane of the atrial septum by the bent portion, and the contact portion can be prevented from being damaged by the deformation of the bent portion.

Brief Description of the Drawings

[0014]

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Mode for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the dimensional ratios in the drawings may be exaggerated for convenience of explanation and may be different from the actual ratios. In this specification, the side inserted into the body cavity of the medical device 10 will be referred to as the "tip" or "tip side", and the hand side for operation will be referred to as the "proximal end" or "proximal end side".

[0016] The medical device in the following embodiments is configured to be able to expand a puncture hole Hh formed in the atrial septum HA of the patient's heart H and further perform a maintenance treatment to maintain the expanded puncture hole Hh at its size.

[0017] As shown in FIG. 1, the medical device 10 of this embodiment has a long shaft portion 20, an expansion body 21 provided at the distal end portion of the shaft portion 20, and a hand operation portion 23 provided at the proximal end portion of the shaft portion 20. An electrode portion 22, which is an energy transmission element for performing the above-described maintenance treatment, is provided on the expansion body 21.

[0018] The shaft portion 20 has a distal shaft portion 30 including a proximal end fixing portion 31 to which the proximal end of the expansion body 21 is fixed and a distal end fixing portion 33 to which the distal end of the expansion body 21 is fixed. The distal shaft portion 30 extends inside the expansion body 21 from the proximal end portion to the distal end portion of the expansion body 21.

[0019] The shaft portion 20 has a storage sheath 25 provided on the outermost peripheral portion. The expansion body 21 is movable forward and backward in the axial direction with respect to the storage sheath 25. The storage sheath 25 can store the expansion body 21 inside it in a state of being moved to the distal end side of the shaft portion 20. By moving the storage sheath 25 to the proximal end side from the state where the expansion body 21 is stored, the expansion body 21 can be exposed.

[0020] Inside the shaft portion 20, a traction shaft 26 is arranged. The traction shaft 26 is provided from the proximal side of the hand operation portion 23 to the distal side of the expander 21, protrudes from the distal end portion of the shaft portion 20, and is connected to the distal end portion of the expander 21, and is slidable with respect to the shaft portion 20. The distal end portion of the traction shaft 26 is fixed to the distal end member 35.

[0021] The distal end member 35 to which the distal end portion of the traction shaft 26 is fixed does not have to be fixed to the expander 21. Thereby, the distal end member 35 can exert a compressive force along the axis of the shaft portion 20 on the expander 21 when the traction shaft 26 slides in the proximal direction with respect to the shaft portion 20. Further, when the expander 21 is housed in the housing sheath 25, by separating the distal end member 35 from the expander 21 toward the distal side, the movement of the expander 21 in the extending direction becomes easy, and the storability can be improved.

[0022] The hand operation portion 23 includes a housing 40 that an operator grips, an operation dial 41 that the operator can rotate, and a conversion mechanism 42 that operates in conjunction with the rotation of the operation dial 41. The traction shaft 26 is held by the conversion mechanism 42 inside the hand operation portion 23. The conversion mechanism 42 can move the held traction shaft 26 forward and backward along the axial direction as the operation dial 41 rotates. As the conversion mechanism 42, for example, a rack and pinion mechanism can be used.

[0023] The shaft portion 20 is preferably formed of a material having a certain degree of flexibility. Examples of such materials include polyolefins such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ionomer, or a mixture of two or more of these, soft polyvinyl chloride resin, polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane, fluororesin such as polytetrafluoroethylene, polyimide, PEEK, silicone rubber, latex rubber, and the like.

[0024] The traction shaft 26 can be formed of a long wire material such as a superelastic alloy such as a nickel-titanium alloy or a copper-zinc alloy, a metal material such as stainless steel, or a resin material having relatively high rigidity.

[0025] The tip member 35 can be formed of, for example, a superelastic alloy such as a nickel-titanium alloy or a copper-zinc alloy, a metal 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 of two or more polymer materials.

[0026] The expander 21 will be described in more detail. As shown in FIGS. 2 and 3, the expander 21 has a plurality of wire portions 50 in the circumferential direction. The wire portions 50 branch and merge along the length direction to form a mesh-like structure. Thereby, the expander 21 can expand and contract in the radial direction. The base end portions of the wire portions 50 extend from the base end fixing portion 31 toward the tip end side. The tip end portions of the wire portions 50 extend from the base end portions of the tip end fixing portion 33 toward the base end side. The wire portions 50 are inclined so as to increase in the radial direction from both axial ends toward the central portion. Further, the wire portion 50 has a concave portion 51 recessed inward in the radial direction of the expander 21 at the axial central portion. The innermost portion in the radial direction of the concave portion 51 is the bottom portion 51a. The concave portion 51 defines a receiving space 51b capable of receiving biological tissue when the expander 21 expands.

[0027] The recess 51 has a proximal-end side upright portion 52 extending radially outward from the proximal end of the bottom portion 51a and a distal-end side upright portion 53 extending radially outward from the distal end of the bottom portion 51a. When the traction shaft 26 slides in the proximal-end direction with respect to the shaft portion 20 and a compressive force is applied to the expander 21, the distal-end side upright portion 53 and the proximal-end side upright portion 52 approach each other, and both come into close contact with the biological tissue received in the receiving space 51b. An electrode portion 22 is disposed along the recess 51 so as to face the receiving space 51b in the proximal-end side upright portion 52. In the present embodiment, six electrode portions 22 are provided along the circumferential direction. The distal-end side upright portion 53 has an outer edge portion 55 bifurcating from the vicinity of the bottom portion 51a and extending radially outward, and a backrest portion 56 disposed between the two outer edge portions 55. Note that the electrode portion 22 may be disposed on the distal-end side upright portion 53.

[0028] The wire portion 50 forming the expander 21 can be formed by laser cutting or the like of a single metal cylindrical member. The wire portion 50 can be formed of a metal material. As this metal material, for example, alloys of titanium-based (Ti-Ni, Ti-Pd, Ti-Nb-Sn, etc.), alloys of copper-based, stainless steel, β-titanium steel, Co-Cr alloy can be used. Note that it is preferable to use an alloy having spring properties such as a nickel-titanium alloy. However, the material of the wire portion 50 is not limited to these, and it may be formed of other materials.

[0029] The electrode portion 22 is connected to an energy supply device (not shown), which is an external device, by a conducting wire portion 66 coated with an insulating coating material. A high-frequency voltage is applied from the energy supply device to an electrode pair composed of two electrode portions 22 via the conducting wire portion 66, and energy is imparted between them. That is, the electrode portion 22 is configured as a bipolar electrode.

[0030] An electrode assembly 60, which is separate from the extension body 21, is attached to the extension body 21. As shown in Fig. 4(a), the electrode assembly 60 has a long wiring portion 61, an electrode portion 22 provided at the tip of the wiring portion 61, and a contact portion 62 provided at the base end of the wiring portion 61. As shown in Fig. 4(b), the wiring portion 61 has a conductive wire portion 61a. The wire portion 61a, the electrode portion 22, and the contact portion 62 can be formed of a metal material. The wire portion 61a is embedded in an adhesive layer 61b sandwiched between insulating layers 61c provided on the surfaces on both sides in the thickness direction of the wiring portion 61. The electrode portion 22 is provided so as to be exposed on the surface of the insulating layer 61c and is electrically connected to the wire portion 61a. Further, the contact portion 62 is a portion that electrically connects the electrode assembly 22 to a lead wire portion 66 provided on the proximal end side of the medical device 1. Similar to the electrode portion 22, the contact portion 62 is exposed on the surface of the insulating layer 61c and is electrically connected to the wire portion 61a.

[0031] As shown in Fig. 5, the shaft portion 20 has an inner layer 20a having a lumen and an outer layer 20b provided on the radially outer side of the inner layer 20a. The electrode assembly 60 and the lead wire portion 66 are arranged between the inner layer 20a and the outer layer 20b in the shaft portion 20 and extend along the axial direction thereof. The lead wire portion 66 is electrically connected to the electrode assembly 60 and the contact portion 62. The two electrode assemblies 60 shown in Fig. 5 are electrically independent and are connected to different lead wire portions 66. In this case, the contact portions 62 are arranged at different positions in the axial direction within the shaft portion 20.

[0032] As shown in Fig. 6, six electrode assemblies 60 are provided on the shaft portion 20 corresponding to the six electrode portions 22 along the circumferential direction. The contact portions 62, each of which connects the electrode assembly 60 and the lead wire portion 66, are all arranged at different positions in the axial direction within the shaft portion 20.

[0033] In the wiring diagram shown in FIG. 7, it is assumed that a voltage is applied between electrode pairs each consisting of electrode portions 22 adjacent to each other. For example, electrode portion 22-1 and electrode portion 22-2 form an electrode pair. In the example of FIG. 7, the contact portions 62-1 to 62-6 of all the electrode assemblies 60-1 to 60-6 are arranged at different positions from each other in the axial direction of the shaft portion 20. Thereby, when the shaft portion 20 is bent under an external force during the assembly or use of the medical device 10, it is possible to prevent the contact portions 62 from contacting each other and causing a short circuit.

[0034] Also, as shown in FIG. 8, the positive electrode portions 22-1, 22-3, 22-5 may be connected to one contact portion 62-A, and the negative electrode portions 22-2, 22-4, 22-6 may be connected to one contact portion 62-B, respectively. Also in this case, the contact portion 62-A and the contact portion 62-B are arranged at different positions from each other in the axial direction of the shaft portion 20.

[0035] A treatment method using the medical device 10 will be described. The treatment method of the present embodiment is performed on a patient suffering from heart failure (left heart failure). More specifically, as shown in FIG. 9, it is a treatment method performed on a patient suffering from chronic heart failure in which the myocardium of the left ventricle of the heart H hypertrophies and the stiffness (hardness) increases, thereby increasing the blood pressure of the left atrium HLa.

[0036] As shown in FIG. 10, first, a puncture hole Hh is created in the atrial septum HA (S1). When forming the puncture hole Hh, the operator delivers an introducer in which a guiding sheath and a dilator are combined to the vicinity of the atrial septum HA. The introducer can be delivered to the right atrium HRa through, for example, the inferior vena cava Iv. Also, the delivery of the introducer can be performed using a guide wire. The operator can insert the guide wire through the dilator and deliver the introducer along the guide wire. Note that the insertion of the introducer into the living body, the insertion of the guide wire, etc. can be performed by a known method such as using an introducer for vascular introduction.

[0037] The operator penetrates a puncture device (not shown) from the right atrial HRa side toward the left atrial HLa side to form a puncture hole Hh. The puncture device is inserted into a dilator and delivered to the atrial septum HA.

[0038] Next, the operator delivers the balloon catheter 100 near the atrial septum HA along the pre-inserted guide wire 11. As shown in FIG. 7, the balloon catheter 100 has a balloon 102 at the tip of the shaft portion 101. When the balloon 102 is placed on the atrial septum HA, it is expanded radially as shown in FIG. 11(a) to expand the puncture hole Hh (S2). At this time, due to the influence of the fibers of the septal tissue, the puncture hole Hh expands to the maximum diameter of the expanded balloon 102 in the direction along the fibers, but it is difficult to expand in other directions, so it becomes an elongated shape as shown in FIG. 11(b).

[0039] Next, the medical device 10 is delivered from the inferior vena cava Iv through the right atrium HRa to near the atrial septum HA, and the expandable body 21 is placed at the position of the puncture hole Hh (S3). When delivering the medical device 10, a guide wire is not used, but a guide wire may be used to stably operate under pulsation.

[0040] The tip of the medical device 10 penetrates the atrial septum HA and reaches the left atrium HLa. Also, as shown in FIG. 12(a), when the medical device 10 is inserted, the expandable body 21 is in a state of being housed in the housing sheath 25. In this figure and FIGS. 13 and 15, the expandable body 21 is shown with a simplified shape. As shown in FIG. 12(b), since the puncture hole Hh is expanded by the balloon 102, the housing sheath 25 can be inserted into the puncture hole Hh.

[0041] Next, as shown in FIG. 13, by moving the storage sheath 25 toward the proximal end side, the expandable body 21 is exposed. As a result, the expandable body 21 expands in diameter, and the recess 51 is disposed in the puncture hole Hh of the atrial septum HA, and the living tissue surrounding the puncture hole Hh is received in the receiving space 51b (S4). As shown in FIG. 9, the shaft portion 20 has a bent portion 27 that bends in one direction toward the proximal end side starting from a position on the proximal end side of the proximal end fixing portion 31. As shown in FIG. 1, the bent portion 27 is linear when stored in the storage sheath 25, and can be bent in one direction by being exposed from the storage sheath 25. Note that the bent portion 27 may bend in one direction starting from the proximal end fixing portion 31. The contact portion 62 is disposed on the proximal end side of the bent portion 27. Thereby, the axial direction of the expandable body 21 can be arranged to be nearly perpendicular to the plane of the atrial septum by the bent portion 27, and the contact portion 62 can be prevented from being damaged by the deformation of the bent portion 27.

[0042] As shown in FIG. 14, when the expandable body 21 expands, the puncture hole Hh is expanded to have a substantially uniform diameter along the circumferential direction. The expandable body 21 changes the shape of the puncture hole Hh, but does not expand in the maximum diameter. Therefore, the maximum diameter of the puncture hole Hh is equal to the diameter in the major axis direction of the puncture hole Hh expanded by the balloon 102 in S2.

[0043] The operator operates the operation unit 23 with the receiving space 51b receiving the living tissue, and moves the traction shaft 26 toward the proximal end side. As a result, as shown in FIG. 15, the expandable body 21 is axially compressed by being pulled in the compression direction by the tip member 35, the atrial septum HA is gripped by the proximal end side standing portion 52 and the distal end side standing portion 53, and the electrode portion 22 is pressed against the living tissue (S5).

[0044] Once the puncture hole Hh is expanded, the operator checks the blood circulation (S6). As shown in FIG. 5, the operator delivers a blood circulation confirmation device 120 to the right atrium HRa via the inferior vena cava Iv. As the blood circulation confirmation device 120, for example, a known echo catheter can be used. The operator displays the echo image obtained by the blood circulation confirmation device 120 on a display device such as a display, and can confirm the blood volume passing through the puncture hole Hh based on the display result.

[0045] Next, the operator performs a maintenance procedure (S7) to inhibit the occlusion of the puncture hole Hh by natural healing and maintain its size. In the maintenance procedure, high-frequency energy is applied to the edge of the puncture hole Hh through the electrode portion 22, and the edge of the puncture hole Hh is cauterized (heated cauterization) by the high-frequency energy. The high-frequency energy is applied by applying a voltage between a pair of adjacent electrode portions 22 in the circumferential direction.

[0046] Even when an external force is applied to the shaft portion 20, etc. between the insertion of the medical device 10 into the living body and the expansion at the puncture hole Hh and the application of energy from the electrode portion 22 to the living tissue, the contact portion 62 between the electrode assembly 50 and the lead wire portion 66 is arranged at different axial positions within the shaft portion 20, so that each electrode portion 22 can be prevented from short-circuiting. Thereby, energy application to the living tissue can be surely performed.

[0047] When the living tissue near the edge of the puncture hole Hh is cauterized through the electrode portion 22, a denatured portion where the living tissue is denatured is formed near the edge. Since the living tissue in the denatured portion loses its elasticity, the puncture hole Hh can maintain the shape when expanded by the expander 21.

[0048] After the maintenance procedure, the operator checks the blood circulation again (S8). When the blood volume passing through the puncture hole Hh is the desired amount, the expander 21 is reduced in diameter, housed in the storage sheath 25, and then removed from the puncture hole Hh. Further, the entire medical device 10 is removed from the living body, and the procedure is terminated.

[0049] As described above, the medical device 10 according to the present embodiment includes an expandable body 21 that can expand and contract in the radial direction, a long shaft portion 20 having a proximal end fixing portion 31 to which the proximal end of the expandable body 21 is fixed at the distal end, a plurality of electrode assemblies 60 including a plurality of electrode portions 22 arranged along the expandable body 21, and a wire portion 66 disposed within the shaft portion 20 and connected to the electrode assembly 60 at a contact portion 62. The plurality of electrode assemblies 60 have at least two or more that are electrically independent, and two or more contact portions 62 to which the two or more electrically independent electrode assemblies 60 are respectively connected are arranged at different positions in the axial direction within the shaft portion 20. The medical device 10 configured in this way can prevent the contact portions 62, which are electrically independent of each other, from coming into contact and short-circuiting when the shaft portion 20 is bent under an external force during the assembly or use of the medical device 10 because they are axially separated from each other.

[0050] A voltage may be applied between electrode pairs formed by the electrode portions 22 included in at least two of the two or more electrically independent electrode assemblies 60. Thereby, when the electrode portion 22 is configured as a bipolar electrode, it is possible to prevent the electrode portions 22 constituting the electrode pair from short-circuiting at the contact portion 62.

[0051] A plurality of electrode pairs may be provided, and all the contact portions 62 to which the electrode assemblies 60 are connected may be arranged at different positions in the axial direction within the shaft portion 20, respectively. Thereby, when a plurality of electrode pairs are provided, it is possible to prevent any of the electrode portions 22 from short-circuiting with other electrode portions 22.

[0052] The electrode assembly 60 may include an electrode portion 22 disposed along the expander 21 and having a conductive surface, an insulating portion 61c disposed on the proximal end side of the electrode portion 22 and having an insulated surface, and a contact portion 62 disposed on the proximal end side of the insulating portion 61c. As a result, the region of the electrode assembly 60 disposed within the shaft portion 20 does not short-circuit except at the contact portion 62. Therefore, by making the axial positions of the contact portions 62 different, a short circuit between the electrode portions 22 can be reliably prevented.

[0053] The shaft portion 20 may include an inner layer 20a having a lumen and an outer layer 20b provided on the radially outer side of the inner layer 20a, and the contact portion 62 may be disposed between the inner layer 20a and the outer layer 20b. Thereby, current leakage can be reliably prevented.

[0054] The shaft portion 20 may have a bent portion 27 that bends in one direction toward the proximal end starting from the proximal end fixing portion 31 or a position on the proximal end side of the proximal end fixing portion 31, and the contact portion 62 may be disposed on the proximal end side of the bent portion 27. The bent portion 27 can be arranged so that the axial direction of the expander 21 is close to being perpendicular to the plane of the atrial septum, and the contact portion 62 can be prevented from being damaged by the deformation of the bent portion 27.

[0055] Note that the present invention is not limited to the above-described embodiments, and various modifications can be made by those skilled in the art within the technical idea of the present invention. In the above-described embodiment, the electrode portion 22 is configured as a bipolar electrode, but it may be two or more monopolar electrodes that are electrically independent. In this case, current is passed between the electrode portion 22 and a counter electrode plate prepared outside the body.

[0056] This application is based on Japanese Patent Application No. 2021-114255 filed on July 9, 2021, the disclosure of which is incorporated herein by reference in its entirety.

Explanation of Reference Numerals

[0057] 10 Medical device 11 Guide wire 20 Shaft portion 20a Inner layer 20b Outer layer 21 Expander 22 Electrode portion 23 Hand operation portion 25 Storage sheath 26 Traction shaft 27 Bending portion 30 Tip shaft portion 31 Base end fixing portion 33 Tip fixing portion 35 Tip member 40 Housing 41 Operation dial 42 Conversion mechanism 50 Wire portion 51 Recess 51a Bottom portion 51b Receiving space 52 Base end side upright portion 53 Tip side upright portion 55 Outer edge portion 56 Contact portion 56a Receiving surface 57 Arm portion 57a Bending portion 60 Electrode assembly 61 Wiring portion 61a Electric wire portion 61b Adhesive layer 61c Insulation layer 62 Contact point portion 66 Conductive wire portion 68 Electrode pair

Claims

1. An expandable body that can expand and contract in the radial direction, A long shaft portion having a proximal end fixing portion to which the proximal end of the expandable body is fixed at the distal end, A plurality of electrode assemblies including a plurality of electrode portions arranged along the expandable body, A wire portion disposed within the shaft portion and connected to the electrode assembly at a contact portion, Comprising, At least two or more of the plurality of electrode assemblies are electrically independent, A medical device in which two or more contact portions to which two or more electrically independent electrode assemblies are respectively connected are arranged at different axial positions within the shaft portion.

2. The medical device according to claim 1, wherein a voltage is applied between electrode pairs formed by the electrode portions of at least two of the two or more electrically independent electrode assemblies.

3. The medical device according to claim 2, wherein a plurality of the electrode pairs are provided, and all of the contact portions to which the electrode assemblies are connected are arranged at different axial positions within the shaft portion.

4. The electrode assembly has an electrode portion arranged along the expandable body and having a conductive surface, an insulating portion arranged on the proximal end side of the electrode portion and having an insulated surface, and the contact portion arranged on the proximal end side of the insulating portion. The medical device according to any one of claims 1 to 3.

5. The shaft portion has an inner layer having a lumen and an outer layer provided on the radially outer side of the inner layer, The medical device according to any one of claims 1 to 4, wherein the contact portion is arranged between the inner layer and the outer layer.

6. The shaft portion has a bent portion that bends in one direction toward the proximal end starting from the proximal end fixing portion or a position on the proximal end side of the proximal end fixing portion, The medical device according to any one of claims 1 to 5, wherein the contact portion is arranged on the proximal end side of the bent portion.

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