JP2022136661A - medical device - Google Patents

Abstract

To provide a medical device capable of concentrating an area to which energy is imparted from an electrode part on a target portion.SOLUTION: A medical device includes an expansion body 21, a long shaft part 20, and an electrode part 22 disposed along the expansion body 21. The expansion body 21 has a recess 51 recessed in the inside in a radial direction at the time of expansion of the expansion body 21, and defining a receiving space 51b capable of receiving biological tissues. The recess 51 has a bottom 51a positioned on the innermost side in the radial direction, a base end side erection part 52 extending from a base end of the bottom 51a to a base end side crown part 52a in the outside in the radial direction, and a tip side erection part 53 extending from a tip of the bottom 51a to a tip side crown part 53a in the outside in the radial direction. One of the base end side erection part 52 and the tip side erection part 53 is provided with the electrode part 22, and the electrode part 22 comprises a pair of electrode elements 22a, 22b adjacent to each other, and is energized between the pair of electrode elements 22a, 22b.SELECTED DRAWING: Figure 3

Description

The present invention relates to medical devices for applying energy to living tissue.

2. Description of the Related Art As a medical device, a medical device is known in which an electrode section is arranged on an expandable body that expands and contracts in vivo, and ablation treatment is performed by cauterizing living tissue with a high-frequency current from the electrode section. Shunt therapy for the interatrial septum is known as one of the treatments by ablation. Shunt therapy forms a shunt (puncture hole) in the interatrial septum, which serves as an escape route for elevated atrial pressure, in patients with heart failure, enabling alleviation of heart failure symptoms. Shunt therapy involves accessing the atrial septum via a transvenous approach and creating a puncture of the desired size. Such a medical device is disclosed, for example, in US Pat.

WO2019-85841

In the medical device, the expandable body has a recess that is recessed radially inward when expanded to define a receiving space capable of receiving living tissue. The medical device of Patent Literature 1 is provided with an electrode section at the bottom of the recess. When applying energy to the living tissue, a voltage is applied between adjacent electrode portions in the circumferential direction. In this case, if the voltage application time is long, the range of tissue injury expands from directly below the electrode section, which may affect surrounding tissues. In addition, since the electrodes are separated from each other, part of the current may leak.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a medical device capable of concentrating a region to which energy is applied from an electrode portion to a target site.

A medical device according to the present invention for achieving the above object is an expandable body that can be expanded and contracted in a radial direction; an electrode section provided along the extension body, the extension body having a concave portion that is recessed radially inward when the extension body is expanded and defines a receiving space capable of receiving living tissue; The concave portion has a bottom portion positioned radially inward, a base-side upright portion extending from the base end of the bottom portion toward a base-side top portion radially outside, and a tip-side top portion radially outside from the tip of the bottom portion. and a distal side upright portion extending toward each other, wherein one of the proximal side upright portion and the distal side upright portion is provided with the electrode portion, and the electrode portion is a pair of electrode elements adjacent to each other. and is energized between the pair of electrode elements.

In addition, a medical device according to the present invention for achieving the above objects is an elongated shaft portion having a distal end portion including an expandable body that can be radially expanded and contracted, and a proximal end fixing portion to which the proximal end of the expandable body is fixed. and an electrode section provided along the expansion body, wherein the expansion body has a recess that is recessed radially inward when the expansion body is expanded and defines a receiving space capable of receiving living tissue. , the recess includes a bottom positioned radially inward, a base-side upright portion extending from the base end of the bottom toward a base-end-side apex radially outward from the bottom, and a distal end radially-outward from the tip of the bottom. and a tip-side upright portion extending toward the top, wherein the electrode portion comprises a pair of electrode elements, current is passed between the pair of electrode elements, and one of the pair of electrode elements is , the end on the bottom side is located closer to the bottom than the other electrode element, and has a larger area in contact with the living tissue than the other electrode element.

The medical device configured as described above can concentrate the region to which energy is applied in the living tissue directly below the electrode section. Therefore, it is possible to prevent the high-frequency current from affecting peripheral tissues other than the target site. In addition, since the distance between the electrode elements is short, current leakage can be suppressed.

The pair of electrode elements may be adjacent along a direction from the bottom portion of the extension body toward the proximal top portion or the distal top portion. Thereby, particularly sufficient energy can be applied along the width direction of the extension body in which the electrode elements are adjacent to each other.

The pair of electrode elements may be adjacent along a direction intersecting a direction from the bottom of the extension body to the proximal top or the distal top. This allows particularly sufficient energy application along the length of the extension body where the electrode elements are adjacent to each other.

The pair of electrode elements may be adjacent to each other such that one electrode element surrounds the other electrode element. This allows a particularly sufficient energy application to be achieved for the region immediately below the inner electrode element.

In the medical device configured as described above, the area to which energy is applied in the living tissue can be concentrated directly below the electrode portion, and the electric field density can be increased as the distance from the bottom portion increases. A changing living tissue can be cauterized uniformly.

One electrode element and the other electrode element are provided on one of the proximal side upright portion and the distal side upright portion, and extend from the bottom portion of the extension body to the proximal side top portion or the distal side top portion. You may make it adjoin along the direction which goes. As a result, since the distance between the electrode elements is short, current leakage can be suppressed, and particularly sufficient energy can be applied along the width direction of the extension body where the electrode elements are adjacent to each other.

One of the electrode elements is provided on one of the proximal side upright portion and the distal side upright portion, and the other electrode element is provided on the other of the proximal side upright portion and the distal side upright portion. can be Thereby, the living tissue between the opposing electrode elements can be sufficiently cauterized.

It is a front view showing the whole medical device composition concerning an embodiment. It is an expansion perspective view of expansion body vicinity. FIG. 4 is an expanded view of the vicinity of the concave portion of the expansion body; FIG. 2 is an explanatory view schematically showing a state in which the expansion body is arranged in the interatrial septum, with the medical device being a front view and the living tissue being a cross-sectional view, respectively. 4 is a flow chart of a procedure using a medical device; FIG. 6 is a diagram showing the state of S2 in FIG. 5, where (a) is an enlarged view of the vicinity of the balloon showing the cross section of the interatrial septum, and (b) is a cross-sectional view of the interatrial septum showing the shape of the puncture hole. . FIG. 6 is a diagram showing the state of S3 in FIG. 5, in which (a) is a cross-sectional view of the interatrial septum and an enlarged view of the vicinity of the expansion body showing the inside of the storage sheath in a see-through manner, and (b) is an enlarged view of the expansion body stored in the puncture hole. FIG. 3 is a cross-sectional view of the interatrial septum with a sheath inserted; FIG. 6 is a diagram showing the state of S4 in FIG. 5, and is an enlarged view of the vicinity of the expansion body showing a cross section of the interatrial septum. FIG. 6 is a diagram showing the state of S4 in FIG. 5, and is a cross-sectional view of the interatrial septum with the puncture hole expanded by the expander. FIG. 6 is a diagram showing the state of S5 in FIG. 5, and is an enlarged view of the vicinity of the expansion body showing a cross section of the interatrial septum. FIG. 4 is an enlarged view showing the arrangement of electrode parts in the extension body; FIG. 11 is an enlarged view showing the arrangement of electrode portions in an extension body according to a first modified example; FIG. 11 is an enlarged view showing the arrangement of electrode portions in an extension body according to a second modified example; FIG. 14 is an expanded view of the vicinity of the concave portion of the expansion body having the electrode portion according to the third modification; FIG. 11 is an enlarged cross-sectional view showing a state in which an extender having an electrode portion according to a third modification is energizing a grasped living tissue; FIG. 16 is an enlarged cross-sectional view showing a state in which an extender having an electrode portion according to a fourth modification is conducting electricity to the grasped living tissue.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the dimensional ratios in the drawings may be exaggerated for convenience of explanation and may differ from the actual ratios. In addition, in this specification, the side of the medical device 10 that is inserted into a living body cavity is referred to as the "distal end" or "distal end side", and the hand side to be operated is referred to as the "proximal end" or "proximal end side".

The medical device in the following embodiments expands a puncture hole Hh formed in the interatrial septum HA of the patient's heart H, and further performs maintenance treatment to maintain the expanded puncture hole Hh at that size. is configured to

As shown in FIG. 1 , the medical device 10 of this embodiment includes an elongated shaft portion 20 , an extension body 21 provided at the distal end portion of the shaft portion 20 , and a hand operation device provided at the proximal end portion of the shaft portion 20 . and a portion 23 . The extension body 21 is provided with an electrode section 22 which is an energy transmission element for performing the maintenance treatment described above.

The shaft portion 20 has a distal end portion 30 including a proximal end fixing portion 31 to which the proximal end of the expandable body 21 is fixed, and a distal end fixing portion 33 to which the distal end of the expandable body 21 is fixed. The distal end 30 of the shaft portion 20 has a shaft extension 32 that extends through the expander 21 from the proximal fixation portion 31 . The shaft portion 20 has a storage sheath 25 provided on the outermost periphery. The expansion body 21 is axially movable forward and backward with respect to the storage sheath 25 . The storage sheath 25 can store the expandable body 21 in the interior thereof while being moved to the distal end side of the shaft portion 20 . By moving the storage sheath 25 toward the proximal end from the state in which the expandable body 21 is stored, the expandable body 21 can be exposed.

The shaft portion 20 has a traction shaft 26 . The traction shaft 26 extends from the proximal end of the shaft portion 20 to the shaft extension portion 32 and has its distal end fixed to the distal end member 35 .

Tip member 35 , to which the distal end of pulling shaft 26 is fixed, may not be fixed to extension body 21 . This allows the tip member 35 to pull the expansion body 21 in the compression direction. Further, when the expandable body 21 is stored in the storage sheath 25, by separating the distal end member 35 from the expandable body 21 toward the distal end side, the expandable body 21 can be easily moved in the extending direction, thereby improving the storing performance. can.

The hand operation unit 23 has a housing 40 gripped by the operator, an operation dial 41 that can be rotated by the operator, and a conversion mechanism 42 that operates in conjunction with the rotation of the operation dial 41 . The traction shaft 26 is held by a conversion mechanism 42 inside the hand operation portion 23 . As the operation dial 41 rotates, the conversion mechanism 42 can axially move the pulling shaft 26 it holds back and forth. As the conversion mechanism 42, for example, a rack and pinion mechanism can be used.

The extension 21 will be explained in more detail. As shown in FIGS. 2 and 3, the expansion body 21 has a plurality of wire portions 50 in the circumferential direction. In this embodiment, four wire portions 50 are provided in the circumferential direction. The wire portions 50 can be expanded and contracted in the radial direction. A proximal end portion of the wire portion 50 extends from the proximal end fixing portion 31 toward the distal end side. A distal end portion of the wire portion 50 extends from a proximal end portion of the distal end fixing portion 33 toward the proximal end side. The wire portion 50 is inclined so as to increase in the radial direction from both ends in the axial direction toward the central portion. In addition, the wire portion 50 has a concave portion 51 that is recessed radially inward of the expansion member 21 at the center portion in the axial direction. The radially innermost portion of the recess 51 is a bottom portion 51a. The concave portion 51 defines a receiving space 51b capable of receiving a living tissue when the expansion body 21 is expanded.

The concave portion 51 has a base end side upright portion 52 extending radially outward from the base end of the bottom portion 51a and a front end side upright portion 53 extending radially outward from the front end of the bottom portion 51a. The proximal-side upright portion 52 extends from the bottom portion 51 a to a proximal-side top portion 52 a positioned radially outward of the extension body 21 . The tip-side upright portion 53 extends from the bottom portion 51 a to a tip-side top portion 53 a positioned radially outward of the extension body 21 . The electrode portion 22 is arranged on the proximal side upright portion 52 or the distal side upright portion 53 so as to face the receiving space 51b. The tip-side upright portion 53 has an outer edge portion 55 bifurcated from the vicinity of the bottom portion 51 a and extending radially outward, and a backrest portion 56 arranged between the two outer edge portions 55 .

The electrode portion 22 is composed of a pair of electrode elements 22a and 22b that are adjacent along the direction from the bottom portion 51a of the extension body 21 toward the proximal top portion 52a. The electrode element 22a and the electrode element 22b are connected to the energy supply device 12, which is an external device, by conductors 58, 58 each covered with an insulating covering material. The conducting wires 58 , 58 are led out through the shaft portion 20 and the hand operation portion 23 and connected to the energy supply device 12 . A high frequency voltage is applied between the electrode elements 22a, 22b from the energy supply 12 via the lead 58 to impart energy therebetween.

The wire part 50 forming the expansion body 21 has, for example, a flat plate shape cut out from a cylinder. The wire material forming the extension body 21 can have a thickness of 50 to 500 μm and a width of 0.3 to 2.0 mm. However, it may have dimensions outside this range. In addition, the wire portion 50 may have a circular cross-sectional shape or other cross-sectional shape.

The wire portion 50 can be made of a metal material. As the metal material, for example, titanium-based (Ti--Ni, Ti--Pd, Ti--Nb--Sn, etc.) alloys, copper-based alloys, stainless steels, β-titanium steels, and Co--Cr alloys can be used. . In addition, it is better 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 may be formed of other materials.

Shaft portion 20 is preferably made of a material having some degree of flexibility. Examples of such materials include polyolefins such as polyethylene, polypropylene, polybutene, ethylene-propylene copolymers, ethylene-vinyl acetate copolymers, ionomers, or mixtures of two or more thereof, soft polyvinyl chloride resins, Polyamide, polyamide elastomer, polyester, polyester elastomer, polyurethane, fluororesin such as polytetrafluoroethylene, polyimide, PEEK, silicone rubber, latex rubber and the like.

The traction shaft 26 can be made of, for example, a long wire rod such as a nickel-titanium alloy, a copper-zinc alloy or other superelastic alloy, a stainless steel or other metal material, or a relatively rigid resin material.

The tip member 35 is made of, for example, nickel-titanium alloy, copper-zinc alloy or other superelastic alloy, stainless steel or other metal material, polyolefin, polyvinyl chloride, polyamide, polyamide elastomer, polyurethane, polyurethane elastomer, polyimide, fluororesin, or the like. or a mixture thereof, or a multi-layer tube made of two or more kinds of polymeric materials.

A treatment method using the medical device 10 will be described. The treatment method of this embodiment is performed on a patient suffering from heart failure (left heart failure). More specifically, as shown in FIG. 4, for a patient suffering from chronic heart failure in which the myocardium in the left ventricle of the heart H is hypertrophied and the stiffness (hardness) is increased, the blood pressure in the left atrium HLa is increased. It is the method of treatment that is performed.

As shown in FIG. 5, first, a puncture hole Hh is created in the interatrial septum HA (S1). When forming the puncture hole Hh, the operator delivers the introducer 210 in which the guiding sheath and the dilator are combined to the vicinity of the interatrial septum HA. The introducer 210 can be delivered to the right atrium HRa, for example, via the inferior vena cava Iv. Also, delivery of the introducer can be done using a guidewire 11 . The operator can pass the guidewire 11 through the dilator and deliver the introducer along the guidewire 11 . Note that the insertion of the introducer into the living body, the insertion of the guide wire 11, and the like can be performed by a known method such as using an introducer for blood vessel introduction.

The operator passes a puncture device (not shown) from the right atrium HRa side toward the left atrium HLa side to form a puncture hole Hh. A puncture device is passed through the dilator and delivered to the atrial septum HA.

Next, the operator delivers the balloon catheter 100 to the vicinity of the interatrial septum HA along the pre-inserted guidewire 11 . As shown in FIG. 6, a balloon catheter 100 has a balloon 102 at the tip of a shaft portion 101 . After the balloon 102 is placed in the interatrial septum HA, it is radially expanded as shown in FIG. 6(a) to widen 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 same diameter as the expanded balloon 102 in the direction along the fibers, but is difficult to expand in other directions. It has an elongated shape as shown in (b).

Next, the medical device 10 is delivered to the vicinity of the interatrial septum HA, and the expander 21 is placed at the puncture hole Hh (S3). A guidewire is not used during delivery of the medical device 10, but a guidewire may be used for stable operation under pulsation. At this time, the distal end of the medical device 10 penetrates the interatrial septum HA and reaches the left atrium HLa. Further, as shown in FIG. 7(a), the expansion body 21 is in a state of being housed in the housing sheath 25 when the medical device 10 is inserted. As shown in FIG. 7B, the puncture hole Hh is expanded by the balloon 102, so that the storage sheath 25 can be inserted through the puncture hole Hh.

Next, as shown in FIG. 8, the expansion body 21 is exposed by moving the storage sheath 25 proximally. As a result, the expansion body 21 is expanded in diameter, and the concave portion 51 is arranged in the puncture hole Hh of the interatrial septum HA to receive the living tissue surrounding the puncture hole Hh in the receiving space 51b (S4). As shown in FIG. 9, by expanding the expansion body 21, the puncture hole Hh is expanded to have a substantially uniform diameter along the circumferential direction. The expansion body 21 changes the shape of the puncture hole Hh, but does not expand the maximum diameter. Therefore, the maximum diameter of the puncture hole Hh is equivalent to the longitudinal diameter of the puncture hole Hh expanded by the balloon 102 in S2.

The operator operates the operation part 23 in a state in which the receiving space 51b receives the living tissue, and moves the traction shaft 26 to the proximal end side. As a result, as shown in FIG. 10, the expandable body 21 is axially compressed by being pulled in the compression direction by the tip member 35, and the interatrial septum HA is compressed by the proximal side upright portion 52 and the distal side upright portion 53. It is gripped and the electrode section 22 is pressed against the living tissue (S5).

After dilating the puncture hole Hh, the operator confirms hemodynamics (S6). The operator delivers the hemodynamic confirmation device 220 to the right atrium HRa via the inferior vena cava Iv, as shown in FIG. As the hemodynamic confirmation device 220, for example, a known echo catheter can be used. The operator can display the echo image acquired by the hemodynamic confirmation device 220 on a display device such as a display, and confirm the amount of blood passing through the puncture hole Hh based on the display result.

Next, the operator performs maintenance treatment to maintain the size of the puncture hole Hh (S7). In the maintenance treatment, high-frequency energy is applied to the edge of the puncture hole Hh through the electrode section 22 to cauterize (heat cauterize) the edge of the puncture hole Hh with the high-frequency energy. High-frequency energy is applied by applying a voltage between the pair of electrode elements 22 a and 22 b that constitute the electrode section 22 .

As shown in FIG. 11, the pair of electrode elements 22a and 22b are arranged so as to be adjacent to each other, so that when a high-frequency current is applied between them, the region to which energy is applied in the living tissue is defined. They can be concentrated directly below the electrode section 22 . Therefore, it is possible to prevent the high-frequency current from affecting surrounding tissues other than the puncture hole Hh, which is the target site. Moreover, since the distance between the electrode elements 22a and 22b is short, current leakage can be suppressed. Since the pair of electrode elements 22a and 22b are adjacent along the length direction of the wire portion 50, a large amount of energy is applied to an area A indicated by a dashed line in the drawing where the electrode elements 22a and 22b are adjacent to each other. be. Therefore, sufficient cauterization can be performed particularly along the width direction of the wire portion 50 .

When the living tissue near the edge of the puncture hole Hh is cauterized through the electrode portion 22, a denatured portion of the living tissue 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 it is expanded by the expander 21 .

After the maintenance treatment, the operator confirms the hemodynamics again (S8), and if the amount of blood passing through the puncture hole Hh is the desired amount, the diameter of the expandable body 21 is reduced and stored in the storage sheath 25. , withdraw from the puncture hole Hh. Furthermore, the entire medical device 10 is removed from the body, and the treatment is finished.

Next, an electrode portion according to a modification will be described. As shown in FIG. 12, the electrode portions 60 of the first modified example are adjacent to each other along a direction that intersects the direction from the bottom portion 51a of the extension body 21 to the base end side top portion 52a, that is, in this example, the direction perpendicular to the direction. An electrode element 60a and an electrode element 60b are arranged. In this case, large energy is applied to a region B indicated by a dashed line in the drawing where the electrode elements 60a and 60b are adjacent to each other. Therefore, sufficient cauterization can be performed particularly along the length direction of the wire portion 50 .

As shown in FIG. 13, the electrode portions 61 of the second modification are arranged adjacently so that one electrode element 61a surrounds the other electrode element 61b. In this case, a large amount of energy is applied to a region where the electrode elements 61a and 61b are adjacent to each other and which is indicated by a dashed line in the figure. Therefore, it is possible to sufficiently cauterize the peripheral portion of the inner electrode element 61b in particular.

The arrangement of the electrode elements in FIGS. 11 to 13 can be arbitrarily selected according to the condition of living tissue. Also, in one extension body 21 , the arrangement of the electrode elements may be different in each wire portion 50 .

As shown in FIG. 14, the electrode portion 62 of the third modification is arranged such that the electrode elements 62a and 62b are adjacent along the direction from the bottom portion 51a of the extension body 21 toward the proximal side top portion 52a. Further, of the pair of electrode elements 62a and 62b, one of the electrode elements 62a located on the bottom 51a side has a larger area of contact with the living tissue than the other electrode element 62b located on the proximal side top 52a side.

As shown in FIG. 15, the electrode section 62 in contact with the living tissue is energized between the electrode elements 62a and 62b to impart energy to the living tissue. At this time, the density of the electric field indicated by the dashed line is low at the portion where the electrode element 61a on the side of the bottom portion 51a with a large area contacts, and is high at the portion where the electrode element 61b on the side of the base end side top portion 52a with a small area contacts. Since the living tissue of the interatrial septum HA becomes thicker as it moves away from the puncture hole Hh, the thickness changes by increasing the electric field density on the side away from the puncture hole Hh by varying the areas of the electrode elements 62a and 62b. Living tissue can be uniformly cauterized.

16, one electrode element 63a and the other electrode element 63b are arranged on the proximal side upright portion 52 and the distal side upright portion 53, respectively. One electrode element 63a has an end portion closer to the bottom 51a than the other electrode element 63b, and has a larger area in contact with the living tissue than the other electrode element 63b. In this case, when electricity is supplied between the electrode elements 63a and 63b, the electric field density is low on the side of one electrode element 63a extending to the bottom portion 51a side, and the electric field density is high on the side of the other electrode element 63b. high. Since the other electrode element 63b is arranged further away from the puncture hole Hh, it is possible to increase the electric field density on the side away from the puncture hole Hh where the thickness of the living tissue increases. As a result, it is possible to uniformly cauterize a biological tissue whose thickness changes.

As described above, the medical device 10 according to the present embodiment has an elongated body 21 that can be radially expanded and contracted, and a distal end portion 30 that includes a proximal end fixing portion 31 to which the proximal end of the expandable body 21 is fixed. and an electrode portion 22 provided along the expansion body 21. The expansion body 21 is recessed radially inward when the expansion body 21 is expanded to define a receiving space 51b capable of receiving living tissue. The recessed portion 51 has a bottom portion 51a located on the innermost side in the radial direction, and a proximal side upright portion 52 extending from the proximal end of the bottom portion 51a toward the radially outer proximal side top portion 52a. , and a tip-side upright portion 53 extending radially outward from the tip of the bottom portion 51a toward the tip-side top portion 53a, and one of the base-side upright portion 52 and the tip-side upright portion 53 has the electrode portion 22. is provided, and the electrode section 22 is composed of a pair of electrode elements 22a and 22b adjacent to each other, and electricity is supplied between the pair of electrode elements 22a and 22b. The medical device 10 configured in this way can concentrate the region to which energy is applied in the living tissue directly below the electrode section 22 . Therefore, it is possible to prevent the high-frequency current from affecting peripheral tissues other than the target site. Moreover, since the distance between the electrode elements 22a and 22b is short, current leakage can be suppressed.

The pair of electrode elements 22a, 22b may be adjacent along the direction from the bottom 51a of the extension 21 toward the proximal top 52a or the distal top 53a. Thereby, particularly sufficient energy can be applied along the width direction of the extension body 21 where the electrode elements 22a and 22b are adjacent to each other.

The pair of electrode elements 60a, 60b may be adjacent along a direction that intersects the direction from the bottom 51a of the extension 21 toward the proximal top 52a or the distal top 53a. Thereby, particularly sufficient energy can be applied along the length direction of the extension body 21 where the electrode elements 60a and 60b are adjacent to each other.

A pair of electrode elements 61a, 61b may be adjacent such that one electrode element 61a surrounds the other electrode element 61b. Thereby, particularly sufficient energy can be applied to the area immediately below the inner electrode element 61a.

In addition, the medical device 10 according to this embodiment is an elongated shaft portion having a distal end portion 30 including an expandable body 21 that can be expanded and contracted in the radial direction and a proximal end fixing portion 31 to which the proximal end of the expandable body 21 is fixed. 20 and an electrode portion 62 provided along the expansion body 21, and the expansion body 21 is recessed radially inward when the expansion body 21 is expanded to define a receiving space 51b capable of receiving living tissue. The recessed portion 51 has a bottom portion 51a positioned radially innermost, a proximal side upright portion 52 extending from the proximal end of the bottom portion 51a toward a radially outer proximal side top portion 52a, and the bottom portion 51a. and a tip-side upright portion 53 extending from the tip of the tip-side upright portion 53 toward the tip-side top portion 53a on the radially outer side. One electrode element 62a of the pair of electrode elements 62a and 62b is energized, and the end on the bottom 51a side is positioned closer to the bottom 51a than the other electrode element 62b, and is closer to the living tissue than the other electrode element 51b. Large contact area. In the medical device 10 configured in this manner, the region to which energy is applied in the living tissue can be concentrated directly below the electrode portion 62, and the electric field density can be increased as the distance from the bottom portion 51a increases. It is possible to uniformly cauterize living tissue with varying thickness.

One electrode element 62a and the other electrode element 62b are provided on one of the proximal side upright portion 52 and the distal side upright portion 53, and extend from the bottom portion 51a of the extension body 21 to the proximal side top portion 52a or the distal side top portion 53a. You may make it adjoin along the direction which goes. As a result, since the distance between the electrode elements 62a and 62b is short, current leakage can be suppressed, and particularly sufficient energy can be applied along the width direction of the extension body 21 where the electrode elements 62a and 62b are adjacent to each other. can be done.

One electrode element 63a is provided on one of the proximal side upright portion 52a and the distal side upright portion 53a, and the other electrode element 63b is provided on the other of the proximal side upright portion 52a and the distal side upright portion 53a. can be Thereby, the living tissue between the opposing electrode elements 63a and 63b can be sufficiently cauterized.

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 concept of the present invention. In the above-described embodiments, the electrode portion 22 is arranged on the proximal side upright portion 52 except for the fourth modified example, but the electrode portion may be arranged on the distal side upright portion 53 .

REFERENCE SIGNS LIST 10 medical device 11 guide wire 12 energy supply device 20 shaft section 21 expander 22 electrode section 22a electrode element 22b electrode element 23 manual operation section 25 storage sheath 26 traction shaft 30 distal section 31 proximal fixing section 33 distal fixing section 35 distal member 40 Case 41 Operation Dial 42 Conversion Mechanism 50 Wire Part 51 Recess 51a Bottom 51b Receiving Space 52 Base Side Upright Part 52a Base Side Top 53 Tip Side Upright 53a Tip Side Top 55 Outer Edge 56 Backrest 58 Wire

Claims (7)

a radially expandable expandable body;
an elongated shaft portion having a distal portion including a proximal fixing portion to which the proximal end of the expander is fixed;
an electrode section provided along the extension;
with
The expandable body has a recess that is recessed radially inward when the expandable body is expanded and defines a receiving space capable of receiving a living tissue,
The concave portion has a bottom positioned radially inward, a base-side rising portion extending from the base end of the bottom toward a base-end-side top radially outward, and a tip-side top radially-outside from the tip of the bottom. a distal upright extending toward the
The electrode portion is provided on one of the proximal side upright portion and the distal side upright portion,
The medical device, wherein the electrode section is composed of a pair of electrode elements adjacent to each other, and current is passed between the pair of electrode elements. 2. The medical device of claim 1, wherein the pair of electrode elements are adjacent along a direction from the bottom of the extension body toward the proximal apex or the distal apex. 2. The medical device of claim 1, wherein the pair of electrode elements are adjacent along a direction that intersects a direction from the bottom of the extension body toward the proximal top or the distal top. 2. The medical device of claim 1, wherein the pair of electrode elements are adjacent such that the electrode element of one surrounds the electrode element of the other. a radially expandable expandable body;
an elongated shaft portion having a distal portion including a proximal fixing portion to which the proximal end of the expander is fixed;
an electrode section provided along the extension;
with
The expandable body has a recess that is recessed radially inward when the expandable body is expanded and defines a receiving space capable of receiving a living tissue,
The concave portion has a bottom positioned radially inward, a base-side rising portion extending from the base end of the bottom toward a base-end-side top radially outward, and a tip-side top radially-outside from the tip of the bottom. a distal upright extending toward the
the electrode unit is composed of a pair of electrode elements, and current is passed between the pair of electrode elements;
One of the pair of electrode elements has an end on the bottom side located closer to the bottom than the other electrode element, and has a larger area in contact with the living tissue than the other electrode element. medical device. One electrode element and the other electrode element are provided on one of the proximal side upright portion and the distal side upright portion, and extend from the bottom portion of the extension body to the proximal side top portion or the distal side top portion. 6. The medical device of claim 5, adjacent along the facing direction. One of the electrode elements is provided on one of the proximal side upright portion and the distal side upright portion, and the other electrode element is provided on the other of the proximal side upright portion and the distal side upright portion. Item 6. The medical device according to item 5.

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