medical devices

Abstract

Provided is a medical device capable of stably holding and expanding biological tissue through a certain amount of pulling operation by means of an expandable body. A medical device (10) comprises: an expandable body (21) expandable in a radial direction; an elongate shaft unit (20) having a tip end (30) including a base end fixing part (31) to which the base end of the expandable body (21) is fixed; and a hand operation unit (23) provided on the base end side of the shaft unit (20). The shaft unit (20) has a pulling shaft (26) that moves in the axial direction to compress the expandable body (21) in the axial direction. The hand operation unit (23) has a pulling operation unit (41) that causes the pulling shaft (26) to move in the axial direction. The pulling shaft (26) and the pulling operation unit (41) are connected to each other with a buffer unit (43) therebetween that is elastically deformable along the axial direction of the pulling shaft (26).

Description

[Technical Field]

[0001] The present invention relates to a medical device having an expandable body that expands and contracts with axial movement of a traction shaft. [Background technology]

[0002] Some medical devices have an expandable body that expands and contracts inside the body. For example, a medical device is known in which an electrode portion is placed on the expandable body and performs ablation treatment, cauterizing biological tissue with high-frequency current from the electrode portion. One known ablation treatment is atrial septal shunt treatment. Shunt treatment involves forming a shunt (puncture hole) in the atrial septum to provide an escape route for elevated atrial pressure in patients with heart failure, thereby alleviating the symptoms of heart failure. In shunt treatment, the atrial septum is accessed via a transvenous approach, and a puncture hole of the desired size is formed. Such a medical device is disclosed, for example, in Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2020-94087 Summary of the Invention [Problem to be solved by the invention]

[0004] The expandable body of Patent Document 1 can self-expand by being exposed from the sheath. The expanded expandable body grips biological tissue, but the gripping and expansion forces can vary greatly depending on the thickness and hardness of the biological tissue. In medical devices with electrodes in the gripping portion, if the gripping force of the electrode on the biological tissue is weak, sufficient contact with the biological tissue cannot be achieved, resulting in the risk of insufficient cauterization or thrombus formation. Furthermore, if the gripping force is too strong, there is a risk of physical damage to the biological tissue. Furthermore, if the expansion force is too weak, the desired amount of expansion cannot be achieved, and if it is too strong, there is a risk of excessive expansion beyond the desired amount.

[0005] The present invention has been made to solve the above-mentioned problems, and aims to provide a medical device that can stably grasp and expand biological tissue using an expandable body with a certain amount of traction operation. [Means for solving the problem]

[0006] The medical device according to the present invention, which achieves the above object, comprises an expansion body that can be expanded and contracted in a radial direction, a long shaft portion having a tip portion including a base end fixing portion to which the base end of the expansion body is fixed, and a hand operation portion provided on the base end side of the shaft portion, wherein the shaft portion has a traction shaft that compresses the expansion body in the axial direction by moving in the axial direction, and the hand operation portion has a traction operation portion that moves the traction shaft in the axial direction, and the traction shaft and the traction operation portion are connected via a buffer portion that can be elastically deformed along the axial direction of the traction shaft. the buffer section has a tip section and a base section opposite to the tip section, the traction operating section has a traction operating section side fixing section fixed to the tip section of the buffer section and a base end side arrangement section arranged on the base end side of the base end section of the buffer section, the traction shaft has a traction shaft side fixing section fixed to the base end section of the buffer section, the traction operating section side fixing section and the traction shaft side fixing section are arranged along the axial direction of the traction shaft, the traction operating section has a first support section formed on the traction operating section side fixing section and supporting a portion of the traction shaft adjacent to the tip side of the tip section of the buffer section, and a base end side arrangement section formed on the traction shaft side and a second support part that supports a portion on the base end side relative to the fixed part, and is movable along the axial direction of the traction shaft from a tip end side position to a base end side position, and the buffer part elastically deforms in a compression direction along the axial direction of the traction shaft so that the base end part of the buffer part changes from a state adjacent to the tip of the second support part of the traction operation part to a state separated from the tip end side by movement of the traction operation part from the tip end side position to the base end side position, and the traction shaft extends linearly between the first support part and the second support part of the traction operation part, and is pulled along the axial direction toward the base end side via the buffer part while extending further to the base end side than the second support part. . [Effects of the Invention]

[0007] In the medical device configured as described above, the traction shaft is pulled by the traction operating unit via the buffer unit, and when the traction operating unit is operated to move a certain amount, the buffer unit elastically deforms according to the thickness and hardness of the biological tissue with which the expandable body comes into contact, so that the traction force on the expandable body can be kept constant regardless of the state of the biological tissue. As a result, the expandable body can stably grasp and expand the biological tissue.

[0008] The buffer unit may have a tip end and a base end opposite to the tip end, the towing operation unit may have a towing operation unit side fixing part fixed to one of the tip end and the base end of the buffer unit, the towing shaft may have a towing operation unit side fixing part fixed to the other of the tip end and the base end of the buffer unit, and the towing operation unit side fixing part and the towing shaft side fixing part may be arranged along the axial direction of the towing shaft. This allows the towing operation unit, the buffer unit, and the towing shaft to be stored compactly.

[0009] The traction operating unit side fixing portion may be fixed to the distal end portion of the buffer unit, and the traction shaft side fixing portion may be fixed to the proximal end portion of the buffer unit, and the buffer unit may be elastically deformed in the compression direction by moving the traction operating unit from the distal end side to the proximal end side along the axial direction of the traction shaft. This makes it possible to keep the traction force on the expandable body constant with a simple structure in which the buffer unit elastically deforms in the compression direction.

[0010] The buffer section may be a coil spring through which the traction shaft can be inserted, thereby allowing the traction shaft and the buffer section to be arranged coaxially, thereby making the structure inside the handheld operation section compact.

[0011] The buffer portion may be one or more coil springs arranged in parallel with the traction shaft, which allows the buffer portion to be attached from the side of the traction shaft, making assembly easier.

[0012] The traction operating unit side fixing portion may be fixed to the base end portion of the buffer unit, and the traction shaft side fixing portion may be fixed to the tip end portion of the buffer unit, and the buffer unit may be configured to elastically deform in the extension direction by moving the traction operating unit from the tip end side to the base end side along the axial direction of the traction shaft. This makes it possible to keep the traction force on the expandable body constant with a simple structure in which the buffer unit elastically deforms in the extension direction.

[0013] A part or the whole of the traction shaft may be elastically deformable along the axial direction of the traction shaft, thereby allowing the traction shaft itself to function as a buffer portion, thereby simplifying the structure.

[0014] The buffer section may be disposed within the hand operation section, thereby preventing the structure of the shaft section from becoming complicated. [Brief explanation of the drawings]

[0015] [Figure 1]1 is a front view showing the overall configuration of a medical device according to an embodiment. [Figure 2] FIG. 10 is an enlarged perspective view of the vicinity of the expansion body. [Figure 3] FIG. 2 is a front view showing the internal structure of the handheld operation unit. [Figure 4] FIG. 10 is an explanatory diagram showing a state in which an expandable body is placed in the atrial septum, with the medical device shown in a front view and the biological tissue shown in a cross-sectional view. [Figure 5] 1 is a flowchart of a procedure using a medical device. [Figure 6] 6A and 6B are diagrams showing the state of S2 in FIG. 5, in which (a) is an enlarged view of the atrial septum in cross section near the balloon, and (b) is a cross section of the atrial septum showing the shape of the puncture hole. [Figure 7] 6A and 6B are diagrams showing the state of S3 in FIG. 5, in which (a) is a cross-sectional view of the atrial septum and an enlarged view of the expandable body with the inside of the storage sheath shown in perspective, and (b) is a cross-sectional view of the atrial septum with the storage sheath inserted through the puncture hole. [Figure 8] FIG. 6 is a diagram showing the state S4 in FIG. 5, and is an enlarged view of the atrial septum in cross section near the expansion body. [Figure 9] FIG. 6 is a diagram illustrating the state S4 in FIG. 5, and is a cross-sectional view of the atrial septum in a state where the puncture hole has been expanded by an expandable body. [Figure 10] FIG. 6 is a diagram showing the state S5 in FIG. 5, and is an enlarged view of the atrial septum in cross section near the expansion body. [Figure 11] 10A and 10B are front views showing the internal structure of the hand-operated operating unit, in which FIG. 10A shows the state before the towing operation, FIG. 10B shows the state in which the buffer section is heavily compressed by the towing operation, and FIG. 10C shows the state in which the buffer section is slightly compressed by the towing operation. [Figure 12] FIG. 10 is a front view showing the internal structure of a handheld operation unit according to a first modified example. [Figure 13] FIG. 10 is a front view showing the internal structure of the handheld operation unit according to the first modified example, showing the state after the pulling operation. [Figure 14] 10A and 10B are a front view and an enlarged cross-sectional view showing the internal structure of a handheld operation unit according to a second modified example, respectively, and a front view and an enlarged cross-sectional view showing the vicinity of the tip of a shaft unit. [Figure 15] FIG. 11 is a front view showing the internal structure of a handheld operation unit according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0016] 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."

[0017] The medical device in the following embodiments is configured to expand a puncture hole Hh formed in the atrial septum HA of a patient's heart H, and to perform a maintenance procedure to maintain the expanded puncture hole Hh at that size.

[0018] 1, the medical device 10 of this embodiment has a 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.

[0019] The shaft portion 20 has a distal 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 shaft portion 20 has a storage sheath 25 provided on the outermost periphery. The expansion body 21 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 toward the distal end of the shaft portion 20. The expansion body 21 can be exposed by moving the storage sheath 25 toward the proximal end from a state in which the expansion body 21 is stored.

[0020] The shaft portion 20 has an outer tube 27 extending from the proximal operating portion 23 to the base end fixing portion 31, and a traction shaft 26 housed inside the outer tube 27. The traction shaft 26 extends inside the outer tube 27 from the base end of the shaft portion 20 to the tip member 35, and its tip portion is fixed to the tip member 35.

[0021] The tip member 35, to which the tip end of the traction shaft 26 is fixed, does not have to be fixed to the expandable body 21. This allows the tip member 35 to pull the expandable body 21 in the compression direction. Furthermore, when storing the expandable body 21 in the storage sheath 25, moving the tip member 35 away from the expandable body 21 toward the tip side facilitates movement of the expandable body 21 in the extension direction, improving storage ease.

[0022] The handheld operation unit 23 has a housing 40 that is held by the surgeon and a traction operation unit 41 that can be operated by the surgeon. As shown in Fig. 3, the housing 40 has a slit portion 60 through which the traction operation unit 41 is slidably inserted, an outer tube insertion opening 61 through which the outer tube 27 is inserted, and a traction shaft insertion opening 62 through which the traction shaft 26 is inserted. The outer tube 27 inserted into the outer tube insertion opening 61 is fixed to an outer tube holding portion 42 provided in the housing 40. The traction shaft 26 extends from the outer tube holding portion 42 to the proximal end side and is led out from the proximal end of the housing 40 in the proximal direction. The traction operation unit 41 has a slide portion 65 that is slidably held within the housing 40.

[0023] A buffer section 43 is provided between the towing operation section 41 and the towing shaft 26. The buffer section 43 is formed of a coil spring that is elastically deformable along the length direction. A tip section 43a of the buffer section 43 is fixed to a towing operation section side fixing section 66 that is formed when the towing operation section 41 extends into the housing 40. A base section 43b of the buffer section 43 is fixed to a towing shaft side fixing section 67 of the towing shaft 26. Since the towing operation section 41 slides and moves from the state shown in FIG. 3 toward the base end side, the buffer section 43, whose tip section 43a is fixed to the towing operation section 41 and whose base section 43b is fixed to the towing shaft 26, can elastically deform in the compression direction.

[0024] As shown in FIG. 2 , the expandable body 21 has multiple wire portions 50 arranged in the circumferential direction. In this embodiment, four wire portions 50 are arranged in the circumferential direction. Each wire portion 50 is expandable and contractible in the radial direction. The base end of each wire portion 50 extends from the base end fixing portion 31 toward the distal end. The distal end of each wire portion 50 extends from the base end of the distal end fixing portion 33 toward the proximal end. The wire portion 50 is inclined so as to increase in the radial direction from both axial ends toward the center. Furthermore, the wire portion 50 has a recess 51 at the axial center that is recessed radially inward of the expandable body 21. The radially innermost portion of the recess 51 is the bottom 51a. The recess 51 defines a receiving space 51b that can receive biological tissue when the expandable body 21 is expanded. The electrode portion 22 is arranged in the recess 51 so as to face the receiving space 51b.

[0025] The wire portion 50 forming the expandable body 21 has, for example, a flat plate shape cut out from a cylinder. The wire forming the expandable body 21 can have a thickness of 50 to 500 μm and a width of 0.3 to 2.0 mm. However, the wire portion 50 may have dimensions outside these ranges. The wire portion 50 may also have a circular cross-sectional shape or other cross-sectional shapes.

[0026] The electrode section 22 is configured, for example, as a bipolar electrode that receives electrical energy from an external energy supply device (not shown). In this case, electricity is passed between the electrode sections 22 arranged in each wire section 50. The electrode section 22 and the energy supply device are connected by a conductor (not shown) covered with an insulating coating material. The conductor is led out via the shaft section 20 and the handheld operation section 23 and connected to the energy supply device.

[0027] Alternatively, the electrode unit 22 may be configured as a monopolar electrode. In this case, electricity is passed between the electrode unit 22 and a return electrode plate prepared outside the body. Alternatively, a heat generating element (electrode chip) that receives high-frequency electrical energy from an energy supply device and generates heat may be used instead of the electrode unit 22. In this case, electricity is passed between the heat generating elements disposed in each wire unit 50. Furthermore, the electrode unit 22 may be configured using an energy transfer element capable of applying energy to the puncture hole Hh, such as microwave energy, ultrasonic energy, coherent light such as a laser, a heated fluid, a cooled fluid, a device that exerts a heating or cooling effect using a chemical medium, a device that generates frictional heat, a heater equipped with an electric wire, etc., and the specific form is not particularly limited.

[0028] The wire portion 50 can be made of a metal material. Examples of such metal materials include titanium-based alloys (Ti-Ni, Ti-Pd, Ti-Nb-Sn, etc.), copper-based alloys, stainless steel, β-titanium steel, and Co-Cr alloys. It is preferable to use alloys with spring properties, such as nickel-titanium alloys. However, the material of the wire portion 50 is not limited to these, and other materials may also be used.

[0029] 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.

[0030] The traction shaft 26 can be formed from 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 with relatively high rigidity.

[0031] 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 multi-layer tube made of two or more types of polymer materials.

[0032] 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 ventricular failure). More specifically, as shown in Fig. 4, this is a treatment method performed on a patient suffering from chronic heart failure in which the blood pressure in the left atrium HLa increases due to hypertrophy of the myocardium of the left ventricle of the heart H and increased stiffness.

[0033] As shown in FIG. 5, first, a puncture hole Hh is created in the atrial septum HA (S1). When forming the puncture hole Hh, the surgeon delivers an introducer 210, which is a combination of a guiding sheath and a dilator, to the vicinity of the atrial septum HA. The introducer 210 can be delivered to the right atrium HRa, for example, via the inferior vena cava IV. The introducer can also be delivered using a guidewire 11. The surgeon can insert the guidewire 11 through the dilator and deliver the introducer along the guidewire 11. Note that insertion of the introducer and the guidewire 11 into the living body can be performed by a known method, such as using an introducer for introducing blood vessels.

[0034] The surgeon passes a puncture device (not shown) from the right atrium HRa side toward the left atrium HLa side to form a puncture hole Hh. The puncture device is passed through a dilator and delivered to the atrial septum HA.

[0035] Next, the surgeon delivers the balloon catheter 100 to the vicinity of the atrial septum HA along the pre-inserted guide wire 11. As shown in FIG. 6, the balloon catheter 100 has a balloon 102 at the tip of a shaft portion 101. Once the balloon 102 is positioned in the atrial septum HA, it is expanded radially as shown in FIG. 6(a) to push open 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 a diameter equal to the maximum diameter of the expanded balloon 102 in the direction along the fibers, but is difficult to expand in other directions, resulting in an elongated shape as shown in FIG. 6(b).

[0036] Next, the medical device 10 is delivered near the atrial septum HA, and the expandable body 21 is positioned at the position of the puncture hole Hh (S3). A guidewire is not used when delivering 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 atrial septum HA and reaches the left atrium HLa. As shown in FIG. 7(a), when the medical device 10 is inserted, the expandable body 21 is housed in the storage sheath 25. As shown in FIG. 7(b), the puncture hole Hh is expanded by the balloon 102, allowing the storage sheath 25 to be inserted through the puncture hole Hh.

[0037] Next, as shown in Fig. 8, the housing sheath 25 is moved proximally to expose the expandable body 21. This causes the expandable body 21 to expand in diameter, and the recess 51 is positioned in the puncture hole Hh in the atrial septum HA, receiving the biological tissue surrounding the puncture hole Hh in the receiving space 51b (S4). As shown in Fig. 9, the expandable body 21 expands, causing the puncture hole Hh to expand 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 the maximum diameter. Therefore, the maximum diameter of the puncture hole Hh is equal to the diameter in the longitudinal direction of the puncture hole Hh expanded by the balloon 102 in S2.

[0038] With the biological tissue received in the receiving space 51b, the surgeon operates the proximal operating unit 23 to move the traction shaft 26 toward the proximal end. As a result, as shown in Fig. 10, the expandable body 21 is pulled in the compression direction by the distal end member 35, and is thereby compressed in the axial direction, the atrial septum HA is grasped by the proximal side erection portion 52 and the distal side erection portion 53, and the electrode portion 22 is pressed against the biological tissue (S5).

[0039] As shown in FIG. 11( a), the traction operation unit 41 is located at the tip of the slit portion 60 before operation. As shown in FIG. 11( b), the surgeon slides the traction operation unit 41 to the base end of the slit portion 60, whereby the traction shaft 26 moves toward the base end and the buffer portion 43 elastically deforms in the compression direction. When the traction shaft 26 starts to move toward the base end, the traction shaft 26 moves toward the base end, compressing the expansion body 21 in the axial direction and clamping the biological tissue. Until the expansion body 21 clamps the biological tissue, the reaction force against the traction of the traction shaft 26 is small, so the deformation of the buffer portion 43 is small, and the traction shaft 21 moves toward the base end. Once the expansion body 21 clamps the biological tissue, the reaction force against the traction of the traction shaft 26 increases. As a result, when the traction operation unit 41 moves further toward the base end, the force causes the buffer portion 43 to elastically deform in the compression direction. In this way, the force operating the traction operation unit 41 is dispersed into a force that elastically deforms the buffer unit 43 and a force that compresses the expansion body 21. As a result, the traction shaft 26 moves toward the base end by a distance L1 shown in Figure 11(b).

[0040] When the thickness of the biological tissue received in the receiving space 51b is thin, the movement distance of the traction shaft 26 until the expansion body 21 clamps the biological tissue becomes larger. Therefore, as shown in FIG. 11(c), even if the sliding movement amount of the traction operation unit 41 is the same as in FIG. 11(b), the compression amount of the buffer unit 43 becomes smaller. In this case, the traction shaft 26 moves toward the proximal end by a distance L2 shown in FIG. 11(c). L2 is greater than L1; that is, when the biological tissue is thinner, the traction shaft 26 moves toward the proximal end more, and the expansion body 21 clamps the biological tissue. Thus, even if the movement amount of the traction operation unit 41 is constant, when the biological tissue is thinner than when it is thick, the action of the buffer unit 43 causes the traction shaft 26 to move further toward the proximal end, allowing the biological tissue to be stably clamped. Furthermore, even when the biological tissue is thick, the buffer section 43 undergoes greater elastic deformation, suppressing the movement of the traction shaft 26, so that even if the amount of movement of the traction operating section 41 is constant, the expansion body 21 can be prevented from clamping the biological tissue with excessive force, causing physical damage, or from excessively expanding the puncture hole Hh and making it larger than the target.

[0041] After the puncture hole Hh is dilated, the surgeon checks the hemodynamics (S6). As shown in FIG. 4, the surgeon delivers a hemodynamics checking device 220 to the right atrium HRa via the inferior vena cava Iv. A known echo catheter, for example, can be used as the hemodynamics checking device 220. The surgeon can display the echo image acquired by the hemodynamics checking device 220 on a display or other display device, and check the amount of blood passing through the puncture hole Hh based on the display results.

[0042] Next, the surgeon performs a maintenance procedure to maintain the size of the puncture hole Hh (S7). In the maintenance procedure, high-frequency energy is applied to the edge of the puncture hole Hh through the electrode units 22, thereby cauterizing (heating and cauterizing) the edge of the puncture hole Hh with the high-frequency energy. The high-frequency energy is applied by applying a voltage between the electrode units 22 adjacent in the circumferential direction.

[0043] When the living tissue near the edge of the puncture hole Hh is cauterized through the electrode portion 22, a denatured portion is formed near the edge where the living tissue is denatured. Because the living tissue in the denatured portion loses its elasticity, the puncture hole Hh can maintain the shape it had when it was expanded by the expander 21.

[0044] After the maintenance treatment, the surgeon checks the hemodynamics again (S8), and if the amount of blood passing through the puncture hole Hh is the desired amount, the expandable body 21 is reduced in diameter, stored in the storage sheath 25, and then removed from the puncture hole Hh. Furthermore, the entire medical device 10 is removed from the living body, and the treatment is completed.

[0045] Next, a first modified example of the handheld operation unit will be described. As shown in FIG. 12 , the handheld operation unit 70 of the first modified example has a traction operation unit 72 in a housing 71, and the outer tube 27 is fixed to an outer tube holding unit 73 inside the housing 71. The traction shaft 26 extending from the outer tube holding unit 73 toward the base end has a traction shaft side fixing unit 78 at its base end, to which a tip end 74a of a buffer unit 74 is fixed. The traction operation unit 72 has a traction operation unit side fixing unit 77 extending into the housing 71, to which a base end 74b of the buffer unit 74 is fixed. Note that in order to insert a guidewire into the lumen of the traction shaft 26, the base end of the traction shaft 26 may be extended from the traction shaft side fixing unit 78 and led out from the base end of the housing 40 in the base end direction. Even in this case, the traction shaft side fixing unit 78 is provided at the base end of the traction shaft 26 when viewed from the entirety of the traction shaft 26.

[0046] 13, when the traction operating unit 72 is operated to slide toward the base end, the traction shaft 26 moves toward the base end and the buffering unit 74 elastically deforms in the extension direction. In this case, if the biological tissue is thick or hard, the buffering unit 74 elastically deforms more in the extension direction, so that the biological tissue can be stably clamped by the expandable body 21 even if the amount of movement of the traction operating unit 72 is constant.

[0047] In this modified example, the base end of the traction shaft 26 extends to and is fixed to at least the traction operation unit side fixing portion 77 of the traction operation unit 72, and part or all of the traction shaft 26 may be a buffer portion that is elastically deformable along the axial direction.

[0048] Next, a second modified example of the hand-operated operation unit will be described. As shown in Fig. 14, a hand-operated operation unit 80 of the second modified example has a traction operation unit 82 in a housing 81, and an outer tube 27 is fixed to an outer tube holding unit 83 inside the housing 81. An intermediate shaft 85 is drawn out toward the base end from the outer tube 27. The intermediate shaft 85 extends to the vicinity of the tip end 30 of the shaft unit 20 and has a traction operation unit side fixing unit 87 at its tip. A tip end 84a of a buffer unit 84 arranged inside the shaft unit 20 is fixed to the traction operation unit side fixing unit 87. The traction shaft 26 has, at its base end, a traction shaft side fixing unit 88 that fixes a base end 84b of the buffer unit 84, and extends toward the tip end from the traction shaft side fixing unit 88.

[0049] When the traction operation unit 82 is operated to slide toward the base end, the intermediate shaft 85 moves toward the base end, and the buffer unit 84 disposed within the shaft portion 20 elastically deforms in the compression direction, while the traction shaft 26 moves toward the base end. In this case, if the biological tissue is thick or hard, the buffer unit 84 elastically deforms more in the compression direction, so that the biological tissue can be stably clamped by the expandable body 21 even if the amount of movement of the traction operation unit 82 is constant. In this way, the buffer unit 84 may be disposed within the shaft portion 20.

[0050] Next, a third modified example of the hand-operated operation unit will be described. As shown in FIG. 15 , the hand-operated operation unit 90 of the third modified example has a traction operation unit 92 in a housing 91. The buffer unit 94 is not arranged coaxially with the traction shaft 26 but is arranged parallel to it at a different position in the radial direction. The traction operation unit 92 has a traction operation unit-side fixing portion 96 to which a distal end 94a of the buffer unit 94 is fixed, and the traction shaft 26 has a traction shaft-side fixing portion 97 to which a proximal end 94b of the buffer unit 94 is fixed. To arrange the buffer unit coaxially with the traction shaft 26, it is necessary to insert the entire traction shaft 26 through the buffer unit and then fix the buffer unit and the traction shaft 26 together. In contrast, by arranging the buffer unit 94 parallel to it at a different position in the radial direction as in the hand-operated operation unit 90 of the third modified example, it is possible to attach the traction shaft-side fixing portion 97 to the traction shaft 26 from the side and then fix the buffer unit 94 to the traction shaft-side fixing portion 97, thereby facilitating assembly. In this modification, a plurality of buffer sections 94 may be provided in parallel.

[0051] As described above, the medical device 10 according to this embodiment comprises the expansion body 21 that can expand and contract radially, the long shaft portion 20 having the distal end portion 30 including the proximal end fixing portion 31 to which the proximal end of the expansion body 21 is fixed, and the proximal operation portion 23 provided on the proximal end side of the shaft portion 20, the shaft portion 20 having the traction shaft 26 that compresses the expansion body 21 in the axial direction by moving it in the axial direction, the proximal operation portion 23 having the traction operation portion 41 that moves the traction shaft 26 in the axial direction, the traction shaft 26 and the traction operation portion 41 being connected via the elastically deformable buffer portion 43 along the axial direction of the traction shaft 26. In the medical device 10 configured in this manner, the traction shaft 26 is pulled by the traction operation portion 41 via the buffer portion 43, and therefore, when the traction operation portion 41 is operated to move a certain amount, the buffer portion 43 elastically deforms depending on the thickness and hardness of the biological tissue with which the expansion body 21 is in contact, and therefore the traction force on the expansion body 21 can be kept constant regardless of the state of the biological tissue. Therefore, the expandable body 21 can stably grasp and expand biological tissue.

[0052] The buffer unit 43 has a tip end 43a and a base end 43b opposite to the tip end 43a, the traction operation unit 41 has a traction operation unit side fixing part 66 fixed to one of the tip end 43a and the base end 43b of the buffer unit 43, and the traction shaft 26 has a traction shaft side fixing part 67 fixed to the other of the tip end 43a and the base end 43b of the buffer unit 43, and the traction operation unit side fixing part 66 and the traction shaft side fixing part 67 may be arranged along the axial direction of the traction shaft 26. This allows the traction operation unit 41, buffer unit 43, and traction shaft 26 to be stored compactly.

[0053] The traction operation unit side fixing portion 66 may be fixed to the tip end 43a of the buffer unit 43, and the traction shaft side fixing portion 67 may be fixed to the base end 43b of the buffer unit 43, and the buffer unit 43 may be elastically deformed in the compression direction by moving the traction operation unit 41 from the tip end side to the base end side along the axial direction of the traction shaft 26. This makes it possible to keep the traction force on the expandable body 21 constant with a simple structure in which the buffer unit 43 elastically deforms in the compression direction.

[0054] The buffer section 43 may be a coil spring through which the traction shaft 26 can be inserted. This allows the traction shaft 26 and the buffer section 43 to be arranged coaxially, making it possible to make the structure inside the handheld operation section 23 compact.

[0055] The buffer 94 may be one or more coil springs arranged in parallel with the traction shaft 26. This allows the buffer 94 to be attached from the side of the traction shaft 26, making assembly easier.

[0056] The traction operation unit side fixed portion 77 may be fixed to the base end portion 74b of the buffer unit 74, and the traction shaft side fixed portion 78 may be fixed to the tip end portion 74a of the buffer unit 74, and the buffer unit 74 may be elastically deformed in the extension direction by moving the traction operation unit 72 from the tip end side to the base end side along the axial direction of the traction shaft 26. This makes it possible to keep the traction force on the expandable body 21 constant with a simple structure in which the buffer unit 74 elastically deforms in the extension direction.

[0057] A part or the whole of the traction shaft 26 may be made elastically deformable along the axial direction of the traction shaft 26. This allows the traction shaft 26 itself to function as a buffer section, thereby simplifying the structure.

[0058] The buffer section 43 may be arranged inside the hand operation section 23. This prevents the structure of the shaft section 20 from becoming complicated.

[0059] The present invention is not limited to the above-described embodiment, and various modifications can be made by those skilled in the art within the technical spirit of the present invention. In the above-described embodiment, the buffer portion 43 is a coil spring, but the buffer portion may be made of rubber, resin, a bellows-like member, or the like as long as it can elastically deform along the axial direction of the shaft portion 20.

[0060] This application is based on Japanese Patent Application No. 2021-36374 filed on March 8, 2021, the disclosures of which are incorporated by reference in their entirety. [Explanation of symbols]

[0061] 10 Medical Devices 11 Guidewire 20 Shaft section 21 Extension 22 Electrode section 23 Handheld operation unit 25 Storage sheath 26 Traction shaft 27 Outer tube 30 Tip 31 Base end fixing part 33 Tip fixing part 35 Tip member 40 cabinets 41 Traction operation section 42 Outer tube holding part 43 Buffer section 43a Tip 43b Proximal end 50 Wire section 51 recess 51a bottom 51b Receptive Space 52 Proximal upright part 53 Tip side standing part 55 outer edge 56 Backrest 56a Receiving surface 57 Arm 57a Bend part 60 Slit section 61 Outer tube insertion opening 62 Towing shaft insertion opening 65 Slide section 66 Towing operation unit side fixed part 67 Towing shaft side fixing part

Claims

1. an expansion body that is radially expandable and contractible; a long shaft portion having a distal end portion including a base end fixing portion to which the base end of the expansion body is fixed; a hand operation unit provided on a base end side of the shaft unit; Equipped with The shaft portion has a traction shaft that compresses the expansion body in the axial direction by moving in the axial direction, The hand-operated unit has a traction operating unit that moves the traction shaft in the axial direction, The traction shaft and the traction operation unit are connected via a buffer unit that is elastically deformable along the axial direction of the traction shaft, The buffer portion has a distal end portion and a proximal end portion opposite the distal end portion, The traction operation unit has a traction operation unit side fixed portion fixed to the tip end portion of the buffer unit, and a base end side arranged portion arranged on the base end side of the base end portion of the buffer unit, the traction shaft has a traction shaft side fixing portion fixed to the base end portion of the buffer portion, The traction operation unit side fixing portion and the traction shaft side fixing portion are arranged along the axial direction of the traction shaft, the traction operating unit has a first support portion formed on the traction operating unit side fixed portion and supporting a portion of the traction shaft adjacent to the tip side of the tip end of the buffer unit, and a second support portion formed on the base end side disposition portion and supporting a portion of the traction shaft on the base end side of the traction shaft, and is movable along the axial direction of the traction shaft from a tip end side position to a base end side position, When the traction operating unit moves from the distal end position to the proximal end position, the buffer unit elastically deforms in a compression direction along the axial direction of the traction shaft so that the proximal end of the buffer unit changes from being adjacent to the distal end of the second support unit of the traction operating unit to being spaced away from the distal end, and the traction shaft extends linearly between the first support unit and the second support unit of the traction operating unit and is pulled toward the proximal end along the axial direction via the buffer unit while remaining extended beyond the second support unit.

2. The medical device according to claim 1 , wherein the buffer portion is a coil spring through which the traction shaft can be inserted.

3. The medical device of claim 1 , wherein the buffer portion is one or more coil springs arranged in parallel with the traction shaft.

4. An expandable body that can expand and contract in the radial direction; a long shaft portion having a distal end portion including a base end fixing portion to which the base end of the expansion body is fixed; a hand operation unit provided on a base end side of the shaft unit; Equipped with The shaft portion has a traction shaft that compresses the expansion body in the axial direction by moving in the axial direction, The hand-operated unit has a traction operating unit that moves the traction shaft in the axial direction, The traction shaft and the traction operation unit are connected via a buffer unit that is elastically deformable along the axial direction of the traction shaft, The buffer portion has a distal end portion and a proximal end portion opposite the distal end portion, The traction operation unit has a traction operation unit side fixing portion fixed to the base end portion of the buffer unit, the traction shaft has a traction shaft side fixing portion fixed to the tip end portion of the buffer portion, The traction operation unit side fixing portion and the traction shaft side fixing portion are arranged along the axial direction of the traction shaft, A medical device in which the buffer section elastically deforms in an extension direction by moving the traction operating section from the distal end side to the proximal end side along the axial direction of the traction shaft.

5. The medical device of claim 4 , wherein a portion or all of the traction shaft is elastically deformable along the axial direction of the traction shaft.

6. The medical device according to any one of claims 1 to 4, wherein the buffer section is disposed within the hand-operated operating section.

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