Medical device

Abstract

Provided is a medical device which is capable of inhibiting, within an expansion body having a linear body and wire parts of electrode assemblies as separate members, the linear body from interfering with the wire parts when shrinking. A medical device 10 is provided with: an expansion body 21 comprising a linear body 50; a shaft part 20 to which a connection part 28 provided at the base end of the expansion body 21 is fixed; and a plurality of electrode assemblies 60 comprising electrode parts 22 and long wire parts 61 having the electrode parts 22 at the tip portions thereof. The expansion body 21 has recess parts 51 which are recessed toward the inside in the radial direction. The recess parts 51 have bottom portions 51a, base end side raised portions 52, and tip end side raised portions 53. The electrode parts 22 are disposed along the base end side raised portions 52 or the tip end side raised portions 53. The shaft part 20 has a tip extension part 30 that extends from the connection part 28 of the expansion body 21 to the tip side. Between the connection part 28 of the expansion body 21 and the tip end of the tip extension part 30, a tip coverage part which bundles the plurality of wire parts 61 of the plurality of electrode assemblies 60 on the outer surface of the tip extension part 30 is provided.

Description

medical devices

[0001] The present invention relates to a medical device for applying energy to living tissue.

[0002] A medical device known in the art uses an electrode placed in an expandable body that expands and contracts within the body, and performs ablation treatment by cauterizing biological tissue with high-frequency current from the electrode. One known ablation treatment is atrial septal shunt therapy. Shunt therapy creates a shunt (a communication hole) in the fossa ovalis of the atrial septum, which serves as an escape route for elevated atrial pressure in patients with heart failure, thereby alleviating the symptoms of heart failure. In shunt therapy, the atrial septum is accessed via a transvenous approach, and a shunt of the desired size is created.

[0003] The expandable body has a recess that recesses radially inward when expanded to define a receiving space capable of receiving biological tissue, and can sandwich the biological tissue from both sides in the thickness direction. The electrode portions are disposed in the recesses. Each electrode portion and a long wiring portion for supplying the electrode constitute an electrode assembly. Such a medical device is disclosed, for example, in Patent Document 1.

[0004] International Publication No. 2019-085841

[0005] Because the expandable body has a large number of electrode portions arranged circumferentially, the linear members forming the expandable body have a complex shape in which they branch and converge along their length. In this case, since it is difficult to arrange the wiring members along the linear members, the wiring members are arranged separately from the linear members and extend from the inside of the expandable body toward the recess. If the wiring members of the electrode assembly are arranged separately from the linear members of the expandable body in this manner, when the radially expanded expandable body is retracted into the sheath and stored, the expandable body may contract with the wiring members sandwiched between the linear members. This may cause the linear members to interfere with the wiring members, potentially resulting in a break in the wiring members.

[0006] The present invention has been made to solve the above-mentioned problems, and aims to provide a medical device in which the linear body and the wiring portion of the electrode assembly are separate entities, and which can prevent the linear body from interfering with the wiring portion when contracted.

[0007] The medical device (1) according to the present invention, which achieves the above-mentioned object, comprises an expandable body made of a plurality of linear bodies and capable of expanding and contracting in a radial direction, and at least one electrode assembly having a connecting portion connected to a base end of the expandable body and including a long shaft portion, an electrode portion, and a long wiring portion connected to the electrode portion, wherein the expandable body has a recess that recesses radially inward when the expandable body is expanded, and the distance between circumferentially adjacent linear bodies among the plurality of linear bodies constituting the expandable body is configured to change according to the expansion and contraction of the expandable body, and the recess has a bottom portion located at the innermost radial direction, a base-side upright portion extending from the base end of the bottom toward a base-side apex on the radial outside, and a tip-side upright portion extending from the tip of the bottom toward a tip-side apex on the radial outside, and the electrode portion extends along the base-side upright portion or the tip-side upright portion. and is arranged so as to be exposed outside the expansion body, the shaft portion has a hollow tip extension portion extending from the connecting portion toward the tip side inside the expansion body, the wiring portion of the electrode assembly has a first end connected to the electrode portion, a second end opposite the first end, and an overhead line portion arranged between the first end and the second end, the tip extension portion has a locking portion between the connecting portion of the shaft portion and the tip of the tip extension portion that locks the portion of the wiring portion that is base-side closer to the overhead line portion to the tip extension portion outside the inner surface of the tip extension portion, and the overhead line portion of the wiring portion extends from the locking portion of the tip extension portion through the inside of the expansion body to the base-side upright portion or the tip-side upright portion, and is arranged in a floating state inside the expansion body when the expansion body is in an expanded state.

[0008] In the medical device (1) configured as described above, the wiring portion is locked by the locking portion inside the expandable body closer to the distal end than the proximal end, so that the wire portion of the wiring portion extending from the locking portion toward the recess is positioned away from the linear body forming the expandable body, thereby preventing the linear body from pinching or interfering with the wiring portion when the radially expanded expandable body is contracted.

[0009] (2) In the medical device of (1), the distal end extension may have a hollow distal end tube main body that includes an inner peripheral surface of the distal end extension, and a tubular distal end covering that covers the outer surface of the distal end tube main body and functions as the locking part. This allows the distal end covering to lock the wiring part so that it is bundled and does not separate from the outer surface of the distal end extension.

[0010] (3) In the medical device of (1) or (2), at least a portion of the linear body located in the recess may have an insertion hole, and the wiring portion may pass through the insertion hole from inside the expansion body at a position closer to the first end than the overhead line portion, exposing the first end to the outside of the expansion body. This allows the medical device to expose the wiring portion extending away from the linear body of the expansion body on a surface facing the outside of the recess, allowing the electrode portion to be appropriately positioned.

[0011] (4) In the medical device of (3), the insertion hole may be provided in the recess closer to the base end apex than the electrode portion disposed on the base end upright portion, thereby enabling the distal end of the wiring portion to be stably disposed in the recess.

[0012] (5) In the medical device of (3), the insertion hole may be provided in the recess closer to the bottom than the electrode portion disposed on the base-side upright portion. This allows the wiring portion extending from the locking portion to the recess to be disposed more inwardly of the expandable body, thereby further preventing interference between the linear portion of the expandable body and the wiring portion as it contracts.

[0013] (6) In the medical device of (3), the insertion hole may be provided in the recess closer to the bottom than the electrode portion disposed on the distal upright portion. This allows the wiring portion extending from the locking portion to the recess to be disposed more inwardly of the expandable body, thereby further preventing interference between the linear portion of the expandable body and the wiring portion as it contracts.

[0014] (7) In any of the medical devices (1) to (6) above, the expandable body may have the plurality of linear bodies branching or merging at least once from the base end toward the recess, and at least a portion of the overhead line portion of the wiring portion may be located between circumferentially adjacent linear bodies among the plurality of linear bodies. This allows the medical device to position the wiring portion, which is likely to be pinched between the linear bodies of the expandable body in terms of its circumferential arrangement, so that the locking portion passes inside the expandable body, thereby preventing the linear bodies from interfering with the wiring portion.

[0015] (8) In the medical device of (2) above, the shaft portion may have a tubular main body portion that includes the distal tube main body portion and extends from the distal end to the proximal end of the shaft portion, and a tubular covering portion that includes the distal covering portion and covers the tubular main body portion, and the connecting portion of the shaft portion may be provided on the covering portion adjacent to the proximal end of the distal covering portion. This allows the medical device to provide a distal covering portion that engages with a wiring portion using the covering portion that covers the shaft portion.

[0016] (9) In any of the medical devices (3) to (6), the length of the wiring portion of the overhead line portion along the longitudinal direction may be longer than the linear distance from the point where the overhead line portion is exposed inside the expandable body from the locking portion to the insertion hole. This reduces the load on the wiring portion when the expandable body expands, thereby preventing breakage of the wiring portion.

[0017] 11 is a front view showing the overall configuration of a medical device according to an embodiment. FIG. 12 is an enlarged perspective view of the vicinity of the expansion body. FIG. 13 is an enlarged front view of the vicinity of the expansion body. FIG. 14 is an enlarged front view of the shaft and a simplified representation of the expansion body. FIG. 15 is an enlarged cross-sectional view of the shaft and a simplified representation of the expansion body. FIG. 16 is an enlarged perspective view of the vicinity of the electrode section of the expansion body. FIG. 17 is an enlarged cross-sectional view of the shaft having a bundling section according to a modified example and a simplified representation of the expansion body. FIG. 18 is an enlarged perspective view of the vicinity of the electrode section of the expansion body having an electrode section according to a modified example. FIG. 19 is an enlarged cross-sectional view of the shaft and a simplified representation of the expansion body having the electrode section of FIG. 10. FIG. 19 is an enlarged cross-sectional view of the shaft and the expansion body when the electrode section is inserted into the expansion body from the side closer to the bottom. FIG. 19 is an enlarged cross-sectional view of the shaft and the expansion body when the electrode section is positioned on the tip-side erecting section. FIG. 19 is an explanatory diagram schematically showing a state in which the expansion body is positioned in the atrial septum, with the medical device shown in a front view and biological tissue shown in a cross-sectional view. FIG. 19 is an enlarged front view showing a state in which the expansion body is gripping biological tissue.

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the dimensional proportions in the drawings may be exaggerated for convenience of explanation and may differ from the actual proportions. In addition, in this specification, the side of the medical device 10 that is inserted into a body cavity will be referred to as the "distal end" or "distal side," and the side that is operated by the operator will be referred to as the "proximal end" or "proximal side."

[0019] The medical device in the following embodiments is configured so that a first through-hole Hh formed in the atrial septum HA of a patient's heart H can be expanded to form a second through-hole Hh2, and then a maintenance procedure can be performed to maintain the expanded second through-hole Hh2 at its size to form a communicating hole Hh.

[0020] 1, the medical device 10 of this embodiment has a hollow, long shaft portion 20, an expansion body 21 provided at the distal end of the shaft portion 20, and a handheld operation unit 23 provided at the proximal end of the shaft portion 20. The expansion body 21 is provided with an electrode portion 22, which is an energy transmission element for performing the maintenance treatment described above.

[0021] The shaft 20 has a hollow distal extension 30 at its distal end that extends from the proximal end of the expandable body 21 to the interior. The distal extension 30 extends along the central axis of the expandable body 21 from near the proximal end of the expandable body 21 to midway along the expandable body 21, specifically to near the recess 51 of the expandable body 21. The shaft 20 also has a connecting portion 28 that is connected to the proximal end of the expandable body 21.

[0022] A storage sheath 25 is provided on the outer periphery of the shaft portion 20. The shaft portion 20 is movable back and forth in the axial direction relative to the storage sheath 25. The storage sheath 25 can store the expansion body 21 inside when it is moved to the distal end side of the shaft portion 20. When the expansion body 21 is stored, the storage sheath 25 can be moved toward the proximal end side to expose the expansion body 21.

[0023] A traction shaft 26 is disposed inside the shaft portion 20 so as to be slidable relative to the shaft portion 20. The traction shaft 26 is provided from the proximal end side of the hand operation unit 23 to the distal end side of the expansion body 21. The traction shaft 26 protrudes from the distal end of the shaft portion 20, specifically from the distal extension portion 30, passes through the inside of the expansion body 21, and protrudes from the distal end of the expansion body 21. The distal end of the traction shaft 26 is fixed to a distal member 35.

[0024] The tip member 35, to which the tip end of the traction shaft 26 is fixed, does not have to be fixed to the expansion body 21. This allows the traction shaft 26 to slide in the proximal direction relative to the shaft portion 20, thereby allowing the tip member 35 to apply a compressive force to the expansion body 21 along the axial center of the shaft portion 20. Furthermore, when storing the expansion body 21 in the storage sheath 25, moving the tip member 35 away from the expansion body 21 toward the tip side facilitates movement of the expansion body 21 in the extension direction, improving storage ease.

[0025] The handheld operation unit 23 has a housing 40 that is held by the surgeon, an operation dial 41 that can be rotated by the surgeon, 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 handheld operation unit 23. The conversion mechanism 42 can move the held traction shaft 26 forward and backward along the axial direction in accordance with the rotation of the operation dial 41. As the conversion mechanism 42, for example, a rack and pinion mechanism can be used.

[0026] The shaft portion 20 is preferably formed from a material having a certain degree of flexibility, such as 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, fluororesins such as polytetrafluoroethylene, polyimide, PEEK, silicone rubber, and latex rubber.

[0027] The traction shaft 26 can be formed of a long linear body made of, for example, 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 with relatively high rigidity.

[0028] The tip member 35 can be formed, for example, from 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, or fluororesin, or a mixture of these, or a multilayer tube made of two or more types of polymer materials.

[0029] As shown in Figures 2 and 3, the expandable body 21 has multiple linear bodies 50 in the circumferential direction. The linear bodies 50 branch and merge along the length between the connecting portion 28 to which their base ends are connected and the distal convergent portion 57 to which their distal ends are connected, forming a mesh-like structure. This allows the expandable body 21 to expand and contract radially. The distance between adjacent linear bodies 50 in the circumferential direction among the multiple linear bodies 50 that make up the expandable body 21 changes as the expandable body 21 expands and contracts. The proximal ends of the linear bodies 50 extend distally from the connecting portion 28 of the expandable body 21. The distal ends of the linear bodies 50 extend proximally from the distal convergent portion 57 of the expandable body 21. When the expandable body 21 is expanded, the linear bodies 50 have a proximal inclined portion 58 that expands in diameter from the proximal connecting portion 28 toward the proximal apex 54. The linear body 50 also has a distal inclined portion 59 whose diameter increases from the distal convergent portion 57 toward the distal apex 55. The linear body 50 has a recess 51 in the axial center that is recessed radially inward of the expandable body 21. The radially innermost portion of the recess 51 is a bottom 51a. The recess 51 defines a receiving space 51b that can receive biological tissue when the expandable body 21 is expanded.

[0030] The recess 51 has a proximal upright portion 52 extending radially outward from the base end of the bottom portion 51a to the proximal apex 54, and a distal upright portion 53 extending radially outward from the tip of the bottom portion 51a. When the traction shaft 26 slides proximally relative to the shaft portion 20 and a compressive force is applied to the expandable body 21, the distal upright portion 53 and the proximal upright portion 52 approach each other and come into close contact with the biological tissue received in the receiving space 51b. An electrode portion 22 is disposed on the proximal upright portion 52 along the recess 51 so as to face the receiving space 51b. That is, the electrode portion 22 is disposed at the middle portion of the expandable body 21 in the central axial direction, along the expandable body 21, and is exposed to the outside of the expandable body 21. In this embodiment, ten electrodes 22 are disposed circumferentially. The electrode portion 22 may also be disposed on the distal upright portion 53.

[0031] The linear body 50 that forms the expandable 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 metal material. Examples of such metal materials that can be used 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 alloys with spring properties, such as nickel-titanium alloys. However, the material of the linear body 50 is not limited to these, and other materials may also be used.

[0032] The electrode unit 22 is connected to an external energy supply device (not shown). A high-frequency voltage is applied from the energy supply device to an electrode pair consisting of two electrode units 22, and energy is imparted between them. In other words, the electrode unit 22 is configured as a bipolar electrode. However, the electrode unit 22 may also be a monopolar electrode. In this case, electricity is passed between the electrode unit 22 and an external electrode.

[0033] An electrode assembly 60, which is separate from the expansion body 21, is attached to the expansion body 21. As shown in Fig. 3, the electrode assembly 60 has a long wiring portion 61 and an electrode portion 22 provided at the tip of the wiring portion 61. The electrode portion 22 has an exposed, conductive surface. The surface of the wiring portion 61 is covered with an insulating layer.

[0034] 4 and 5 , the wiring portion 61 constituting the electrode assembly 60 has a first end 61a connected to the electrode portion 22, a second end (not shown) opposite the first end 61a, and an interconnection portion 61b disposed between the first end 61a and the second end. The portion of the wiring portion 61 on the second end side extends along the shaft portion 20, and the interconnection portion 61b extends away from the shaft portion 20 inside the expansion body 21 toward the recess 51 of the linear body 50, penetrating the linear body 50 so that the first end 61a having the electrode portion 22 is exposed facing the outside of the expansion body 21. A tubular distal end covering portion 27 is provided between the connecting portion 28 of the expansion body 21 and the distal end of the distal extension portion 30, bundling and engaging the multiple wiring portions 61 of the multiple electrode assemblies 60 on the outer surface of the distal extension portion 30. For this reason, the wiring portion 61 runs along the shaft portion 20 from the base end side to the tip end side up to the tip position of the tip covering portion 27, and is spaced apart from the shaft portion 20 distal to the tip position of the tip covering portion 27. The tip covering portion 27 can be formed from the same resin material as the shaft portion 20. In this way, the tip extension portion 30 has the tip covering portion 27 between the connecting portion 28 of the shaft portion 20 and the tip of the tip extension portion 30, and the portion of the wiring portion 61 on the base end side of the overhead line portion 61b is located outside the inner circumferential surface of the tip extension portion 30 and functions as a locking portion that locks onto the tip extension portion 30.

[0035] As shown in Figure 5, the shaft portion 20 proximal to the expansion body 21 has a covering portion 20a that covers its outer surface, and the wiring portion 61 of the electrode assembly 60 extends between the covering portion 20a and the outer surface of the shaft portion 20. The distal extension portion 30 has a hollow distal tube main body portion 30a that includes the inner circumferential surface of the distal extension portion 30, and a tubular distal covering portion 27 that covers the outer surface of the distal tube main body portion 30a. The distal covering portion 27 extends from the inside of the connecting portion 28 of the expansion body 21 to the interior of the expansion body 21. The wiring portion 61 extends between the distal covering portion 27 and the outer surface of the distal tube main body portion 30a. As a result, the wiring portion 61 is bundled on the outer surface of the distal extension portion 30 located inside the expansion body 21. The position at which the wiring portion 61 leaves the shaft portion 20 is located distal to the connecting portion 28 of the expansion body 21 because the wiring portions 61 are bundled by the distal covering portion 27 inside the expansion body 21 distal to the connecting portion 28. That is, the distal covering portion 27, which serves as a locking portion, locks the multiple wiring portions 61 inside the expansion body 21 distal to the base end of the expansion body 21. Therefore, the wire portions 61b of the wiring portions 61 are arranged inside the expansion body 21 at a position spaced inward from the base-side inclined portion 58 of the linear body 50, extending toward the recess 51 in a suspended state. That is, the wire portions 61b of the wiring portions 61 extending from the exposed position of the distal covering portion 27 (locking portion) toward the recess 51 are arranged at a position spaced apart from the linear body 50 that forms the expansion body 21. For this reason, when the expandable body 21 is in an expanded state, the overhead line portion 61b is not engaged with either the expandable body 21 or the distal extension portion 30. As a result, when the radially expanded expandable body 21 is pulled into and stored in the storage sheath 25, the proximal inclined portion 58 of the contracting linear body 50 is less likely to come into contact with the wiring portion 61, thereby preventing the wiring portion 61 from interfering with and being damaged by the linear body 50. Since the expandable body 21 has a shape in which the linear bodies 50 branch and merge, at least a portion of the overhead line portion 61b of the wiring portion 61 along the length direction is disposed between the linear bodies 50 adjacent to each other in the circumferential direction.Due to this structure, when the expansion body 21 contracts, there is a possibility that the wiring portion 61 will be pinched between the linear bodies 50 that are adjacent to each other in the circumferential direction and be damaged. However, since the tip covering portion 27 positions the wiring portion 61 on the inside, away from the linear body 50, the possibility of it being pinched by the linear body 50 is reduced.

[0036] As shown in FIG. 6 , the linear body 50 has an insertion hole 51c in the proximal upright portion 52. The insertion hole 51c is an opening whose shape and dimensions do not change substantially whether the expandable body 21 is in the expanded or contracted state. When the wiring portion 61 is inserted through the insertion hole 51c, the distal end portion including the electrode portion 22 is exposed to the outside of the expandable body 21. The wiring portion 61 has an exposed portion 61c between the power line portion 61b and the first end 61a, which is exposed to the outside of the expandable body 21. The insertion hole 51c is located in the proximal upright portion 52 of the recess 51, closer to the proximal apex 54 than the electrode portion 22, which is located near the bottom 51a. Therefore, the wiring portion 61 passing through the insertion hole 51c extends toward the bottom 51a of the recess 51. The length of the wire portion 61b along the longitudinal direction of the wiring portion 61 is longer than the linear distance from the point where the wire portion 61b is exposed inside the expandable body 21 from the tip covering portion 27 to the insertion hole 51c (see FIG. 5). Therefore, when the expandable body 21 expands, the wiring portion 61 is less likely to be subjected to load, and breakage of the wiring portion 61 can be suppressed.

[0037] 7 , the distal end of the covering portion 20a that constitutes the shaft portion 20 and covers the tube main body portion 20b including the distal tube main body portion 30a may be referred to as the distal covering portion 20c. In this case, the covering portion 20a extends from the proximal side of the expandable body 21, past the connecting portion 28 of the expandable body 21, and into the interior of the expandable body 21, and the distal covering portion 20c engages the wiring portion 61. The wiring portion 61 of the electrode assembly 60 runs along the shaft portion 20 in the region where the covering portion 20a is provided, and distal to the distal position of the covering portion 20a are located a wire portion 61b that extends away from the shaft portion 20 toward the recess 51, and a first end portion 61a that is exposed outside the expandable body 21 and connected to the electrode portion 22.

[0038] As shown in Fig. 8, the insertion hole 51c formed in the linear body 50 may be formed at a position close to the bottom 51a of the recess 51. In this case, as shown in Fig. 9, the radial positions of the tip covering portion 27 and the insertion hole 51c become closer, and the wiring portion 61 of the electrode assembly 60 has the overhead line portion 61b passing inside the linear body 50 farther from the base-side inclined portion 58 and penetrating the linear body 50 at a position farther from the base-side apex 54. This further reduces the possibility that the wiring portion 61 will interfere with the linear body 50 when the expandable body 21 is contracted.

[0039] 10 , the insertion hole 51c may be located near the bottom 51a of the base-side upright portion 52, and the first end 61a of the wiring portion 61 that passes through the insertion hole 51c may extend from the bottom 51a toward the base-side apex 51c. That is, the insertion hole 51c may be located closer to the bottom 51a than the electrode portion 22. This allows the wiring portion 61 of the electrode assembly 60 to pass through the linear body 50 at a position farther from the base-side apex 51c, so that the wire portion 61b of the wiring portion 61 that extends from the tip covering portion 27 to the recess 51 is located further inward, further reducing the possibility of the wiring portion 61 interfering with the linear body 50 when the expandable body 21 is contracted.

[0040] 11 , electrode unit 22 may be disposed on distal upright portion 53 of recess 51. In this case, insertion hole 51c is provided in recess 51 closer to bottom 51a than electrode unit 22 disposed on distal upright portion 53. By disposing electrode unit 22 on distal upright portion 53, wiring unit 61 extending from distal covering portion 27 to electrode unit 22 does not have a folded-back portion, and therefore, wire section 61b of wiring unit 61 can be disposed further inward, further reducing the possibility of wiring unit 61 interfering with linear body 50 when expandable body 21 is contracted.

[0041] When using the medical device 10, a first through-hole Hh1 is formed in advance at the position of the fossa ovalis in the atrial septum HA. The medical device 10 expands and pushes open the first through-hole Hh1 to form a substantially circular second through-hole Hh2, and then cauterizes the edge of the second through-hole Hh2. As a result, the medical device 10 forms a communicating hole Hh that maintains its size, i.e., its patency. As shown in FIG. 12 , 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 expandable body 21 is positioned at the position of the pre-formed first through-hole Hh1. The distal end of the medical device 10 penetrates the atrial septum HA and reaches the left atrium HLa.

[0042] When inserting the medical device 10, the expandable body 21 is stored in the storage sheath 25 and is in a contracted state, and the expandable body 21 can be exposed by moving the storage sheath 25 toward the proximal end from a state in which the storage sheath 25 has penetrated the atrial septum HA. When the expandable body 21 is exposed, the diameter of the expandable body 21 expands in the radial direction, and the recess 51 is positioned in the first through-hole Hh1 of the atrial septum HA, and the receiving space 51b receives the biological tissue surrounding the first through-hole Hh1.

[0043] As shown in FIG. 13 , when the traction shaft 26 is moved proximally while the receiving space 51b accommodates the biological tissue, the expandable body 21 is pulled in the compression direction by the distal member 35 and compressed axially. The atrial septum HA is grasped by the proximal upright portion 52 and the distal upright portion 53 that form the recess 51, and the electrode portion 22 is pressed against the biological tissue. At this time, the radial position of the recess 51 moves outward, causing the first through-hole Hh1 to expand radially, forming a second through-hole Hh2. The diameter of the second through-hole Hh2 is larger than that of the first through-hole Hh1. The fossa ovalis, where the second through-hole Hh2 is formed, has a smaller wall thickness than other parts of the atrial septum HA. Therefore, the recess 51 of the expandable body 21 can clamp the biological tissue surrounding the second through-hole Hh2, pressing the electrode portion 22 against the biological tissue.

[0044] With the electrode portion 22 pressed against the biological tissue, high-frequency energy is applied through the electrode portion 22 to the edge of the second through-hole Hh2, i.e., the biological tissue surrounding the second through-hole Hh2, thereby cauterizing (heating and cauterizing) the edge of the second through-hole Hh2 with the high-frequency energy. The high-frequency energy is applied by applying a voltage between a pair of circumferentially adjacent electrode portions 22. This prevents the communication hole Hh from closing due to natural healing and maintains its size. When the expandable body 21 is contracted and removed after cauterization, the second through-hole Hh2 contracts slightly in the radial direction, forming a communication hole Hh.

[0045] When the medical device 10 is in use, hemodynamics is confirmed by the hemodynamic confirmation device 120 delivered to the right atrium HRa via the inferior vena cava Iv. A known echo catheter, for example, can be used as the hemodynamic confirmation device 120. The surgeon can display the echo image acquired by the hemodynamic confirmation device 120 on a display or other display device, and can confirm the amount of blood passing through the communication hole Hh based on the displayed image.

[0046] When removing the expandable body 21 after cauterization by the electrode section 22, the storage sheath 25 is advanced relative to the shaft section 20, and the expandable body 21 is pulled from the base end side into the storage sheath 25. At this time, the wiring section 61, which is positioned at a position separate and inward from the linear body 50 of the expandable body 21 by the distal covering section 27, is less likely to interfere with the contracting linear body 50, and the possibility of the wiring section 61 being damaged by the linear body 50 can be reduced.

[0047] As described above, the medical device 10 according to this embodiment (1) comprises an expandable body 21 made up of a plurality of linear bodies 50 and capable of expanding and contracting in the radial direction, and at least one electrode assembly 60 having a connecting portion 28 connected to the base end of the expandable body 21 and including a long shaft portion 20, an electrode portion 22, and a long wiring portion 61 connected to the electrode portion 22. The expandable body 21 has a recess 51 that is recessed radially inward when the expandable body 21 is expanded, and The recess 51 has a bottom 51a located at the innermost position in the radial direction, a base-side upright portion 52 extending from the base end of the bottom 51a toward a base-side apex 54 on the radially outer side, and a tip-side upright portion 53 extending from the tip of the bottom 51a toward a tip-side apex 55 on the radially outer side, and the electrode portion 22 is configured such that the distance between adjacent linear bodies 50 in the circumferential direction among the plurality of linear bodies 50 constituting the recess 51 changes according to the expansion and contraction of the expandable body 21. The shaft portion 20 has a hollow distal extension portion 30 extending from the connecting portion 28 to the distal end side inside the expansion body 21, and the wiring portion 61 of the electrode assembly 60 has a first end 61 a connected to the electrode portion 22, a second end opposite to the first end 61 a, and an overhead line portion 61 b ​​arranged between the first end 61 a and the second end. The distal extension portion 30 is arranged along the connecting portion 28 of the shaft portion 20. Between the distal end portion 28 and the distal end of the distal extension portion 30, there is a locking portion 27 that locks the portion of the wiring portion 61 closer to the base end than the overhead line portion 61b to the distal extension portion 30, outside the inner surface of the distal extension portion 30, and the overhead line portion 61b of the wiring portion 61 extends from the locking portion 27 of the distal extension portion 30 through the inside of the expandable body 21 to the base-side upright portion 52 or the distal-side upright portion 53, and is arranged in a floating state inside the expandable body 21 when the expandable body 21 is in an expanded state. In the medical device 10 configured in this manner, the multiple wiring portions 61 are locked by the locking portions 27 inside the expandable body 21 closer to the tip than the base end, so that the overhead line portion 61b of the wiring portion 61 extending from the locking portion 27 toward the recess 51 is arranged at a position separated from the linear body 50 that forms the expandable body 21. This makes it possible for the medical device 10 to prevent the linear body 50 from interfering with the wiring portion 61, such as pinching it, when the expandable body 21 that has expanded in the radial direction is contracted.

[0048] (2) In the medical device 10 described in (1) above, the distal end extension 30 may have a hollow distal end tube main body 30a that includes the inner peripheral surface of the distal end extension 30, and a tubular distal end covering 27 that covers the outer surface of the distal end tube main body 30a and functions as a locking part. This allows the distal end covering 27 to lock the wiring part 61 so as to bundle it and prevent it from separating from the outer surface of the distal end extension 30.

[0049] (3) In the medical device 10 described in (1) or (2) above, at least a portion of the linear body 50 located in the recess 51 may have an insertion hole 51c, and the wiring portion 61 may pass through the insertion hole 51c from the inside of the expansion body 21 on the first end 61a side of the overhead line portion 61b, exposing the first end 61a to the outside of the expansion body 21. This allows the medical device 10 to expose the wiring portion 61 extending away from the linear body 50 of the expansion body 21 on the surface facing the outside of the recess 51, allowing the electrode portion 22 to be appropriately positioned.

[0050] (4) In the medical device 10 described in (3) above, the insertion hole 51c may be provided closer to the base-side apex 54 than the electrode portion 22 arranged on the base-side upright portion 52 in the recess 51. This allows the distal end of the wiring portion 61 of the medical device 10 to be stably arranged in the recess 51.

[0051] (5) In the medical device 10 described in (3) above, the insertion hole 51c may be provided closer to the bottom 51a than the electrode portion 22 arranged on the base-side upright portion 52 in the recess 51. This allows the medical device 10 to arrange the wiring portion 61 extending from the locking portion 27 toward the recess 51 more inwardly in the expandable body 21, thereby further preventing the linear body 50 of the contracting expandable body 21 from interfering with the wiring portion 61.

[0052] (6) In the medical device 10 described in (3) above, the insertion hole 51c may be provided closer to the bottom 51a than the electrode portion 22 arranged on the distal upright portion 53 in the recess 51. This allows the medical device 10 to arrange the wiring portion 61 extending from the locking portion 27 toward the recess 51 further inside the expandable body 21, thereby further preventing the linear body 50 of the contracting expandable body 21 from interfering with the wiring portion 61.

[0053] (7) In the medical device 10 of any of (1) to (6) above, the expansion body 21 may have a plurality of linear bodies 50 branching or merging at least once from the base end toward the recess 51, and at least a portion of the overhead line portion 61b of the wiring portion 61 may be located between circumferentially adjacent linear bodies 50 among the plurality of linear bodies 50. In this way, the medical device 10 can position the wiring portion 61, which is likely to be pinched between the linear bodies 50 of the expansion body 21 in terms of the circumferential arrangement relationship, so that the locking portion 27 passes inside the expansion body 21, thereby preventing the linear bodies 50 from interfering with the wiring portion 61.

[0054] (8) In the medical device 10 of (2) above, the shaft portion 20 may have a cylindrical main body portion 20b that includes a distal tube main body portion 30a and extends from the distal end to the proximal end of the shaft portion 20, and a tubular covering portion 20a that includes a distal covering portion 20c and covers the cylindrical main body portion 20b, and the connecting portion 27 of the shaft portion 20 may be provided on the covering portion 20a adjacent to the proximal end of the distal covering portion 20c. This allows the medical device 10 to provide the distal covering portion 20c that engages the wiring portion 61 using the covering portion 20a that covers the shaft portion 20.

[0055] (9) In any of the medical devices 10 described above in (3) to (6), the length of the wire portion 61b along the longitudinal direction of the wiring portion 61 may be longer than the linear distance from the point where the wire portion 61b is exposed inside the expandable body 21 from the locking portion 27 to the insertion hole 51c. This reduces the load on the wiring portion 61 when the expandable body 21 expands, thereby preventing breakage of the wiring portion 61.

[0056] The present invention is not limited to the above-described embodiment, and various modifications may be made by those skilled in the art within the technical spirit of the present invention. In the above-described embodiment, the locking portion that locks and ties the portion of the wiring portion 61 proximal to the distal extension portion 30 relative to the overhead line portion 61b is the tubular distal covering portion 27. However, the locking portion may be configured as a non-tubular member as long as it can lock the wiring portion 61 outside the inner circumferential surface of the distal extension portion 30. For example, a portion of the shaft portion 20 including the distal extension portion 30 may be a two-layer tube having an outer layer outside an inner layer, with the wiring portion 61 sandwiched between the inner and outer layers, and the wiring portion 61 locked within the distal extension portion 30 in the longitudinal direction. Alternatively, a portion of the shaft portion 20 including the distal extension portion 30 may be a multi-lumen tube with multiple lumens, with the wiring portion 61 housed in a lumen formed outside a central lumen through which the traction shaft 26 is inserted, and the wiring portion 61 locked within the distal extension portion 30 in the longitudinal direction. Alternatively, wiring portion 61 may be fixed to the outer peripheral surface of tip extension portion 30 with an adhesive, and wiring portion 61 may extend from the tip of the portion fixed with the adhesive toward recess 51 of linear body 50 .

[0057] This application is based on Japanese Patent Application No. 2023-163538 filed on September 26, 2023, the disclosures of which are incorporated herein by reference in their entirety.

[0058] 10 Medical device 11 Guide wire 20 Shaft portion 20a Covering portion 21 Expansion body 22 Electrode portion 23 Proximal operation portion 25 Storage sheath 26 Traction shaft 27 Tip covering portion (locking portion) 28 Connecting portion 30 Tip extension portion 35 Tip member 40 Housing 50 Linear body 51 Recess 51a Bottom 51b Receiving space 51c Insertion hole 52 Base end side standing portion 53 Tip end side standing portion 54 Base end side apex 55 Tip end side apex 57 Tip convergence portion 58 Base end side inclined portion 59 Tip end side inclined portion 60 Electrode assembly 61 Wiring portion

Claims

1. An expansion body which is made up of a plurality of linear bodies and which can be expanded and contracted in the radial direction; a hollow and long shaft portion having a connecting portion connected to the base end of the expansion body; and at least one electrode assembly including an electrode portion and a long wiring portion connected to the electrode portion, wherein the expansion body has a recess which is recessed radially inward when the expansion body is expanded, and the distance between adjacent linear bodies in the circumferential direction among the plurality of linear bodies which constitute the expansion body changes according to the expansion and contraction of the expansion body, the recess has a bottom portion located at the innermost radial direction, a base end side upright portion which extends from the base end of the bottom portion toward the base end side apex on the radial outside, and a tip end side upright portion which extends from the tip end of the bottom portion toward the tip end side apex on the radial outside, the electrode portion is arranged so as to be exposed to the outside of the expansion body along the base end side upright portion or the tip end side upright portion, and the shaft portion has a hollow tip extension portion which extends from the connecting portion toward the tip side within the interior of the expansion body, The wiring portion of the electrode assembly has a first end connected to the electrode portion, a second end opposite the first end, and an overhead line portion arranged between the first end and the second end, and the tip extension portion has a locking portion between the connecting portion of the shaft portion and the tip of the tip extension portion, which locks the portion of the wiring portion that is base end side than the overhead line portion to the tip extension portion outside the inner surface of the tip extension portion, and the overhead line portion of the wiring portion extends from the locking portion of the tip extension portion through the inside of the expansion body to the base end upright portion or the tip end upright portion, and is positioned in a suspended state inside the expansion body when the expansion body is in an expanded state.

2. The medical device of claim 1, wherein the tip extension portion has a hollow tip tube main body portion that includes the inner surface of the tip extension portion, and a tubular tip covering portion that covers the outer surface of the tip tube main body portion and functions as the engaging portion.

3. A medical device as described in claim 1 or 2, wherein at least a portion of the linear body located in the recess has an insertion hole, and the wiring portion passes through the insertion hole from the inside of the expansion body on the first end side relative to the overhead line portion, exposing the first end to the outside of the expansion body.

4. A medical device as described in claim 3, wherein the insertion hole is provided in the recess closer to the base end apex than the electrode portion arranged on the base end upright portion.

5. A medical device as described in claim 3, wherein the insertion hole is provided in the recess closer to the bottom than the electrode portion arranged on the base end side standing portion.

6. A medical device as described in claim 3, wherein the insertion hole is provided in the recess closer to the bottom than the electrode portion arranged on the tip side standing portion.

7. A medical device as described in claim 1 or 2, wherein the expansion body has a plurality of linear bodies branching or merging at least once from the base end toward the recess, and at least a portion of the wire portion of the wiring section is located between circumferentially adjacent linear bodies among the plurality of linear bodies.

8. A medical device as described in claim 2, wherein the shaft portion has a tube main body portion including the tip tube main body portion and extending from the tip to the base end of the shaft portion, and a tubular covering portion including the tip covering portion and covering the tube main body portion, and the connecting portion of the shaft portion is provided on the covering portion adjacent to the base end of the tip covering portion.

9. A medical device as described in claim 3, wherein the length along the longitudinal direction of the wiring portion of the overhead line portion is longer than the straight-line distance from the point where the overhead line portion is exposed from the engaging portion to the inside of the expandable body to the insertion hole.

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