Medical device
The medical device addresses the issue of torsional force-induced twisting in expandable bodies by incorporating a towing portion within the recess of the expanding body, ensuring stable expansion and preventing damage to the coating and electrode.
Patent Information
- Application Number
- PCT/JP2024/032325
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-09-26
- Filing Date
- 2024-09-10
- Publication Date
- 2025-04-03
AI Technical Summary
Existing medical devices with expandable bodies prone to shifting and twisting when a torsional force is applied, leading to potential expansion failure, coating peeling, and electrode breakage.
A medical device featuring a self-expanding body with a recess that includes a towing portion to change the shape and radial position of the recess, preventing twisting by restricting deviation in the circumferential direction.
The device effectively suppresses twisting of the expanding body, prevents expansion failure, and maintains the integrity of the coating and electrode portion.
Smart Images
Figure JP2024032325_03042025_PF_FP_ABST
Abstract
Description
medical devices
[0001] The present invention relates to a medical device in which an expandable and contractible expander has a recess.
[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 involves creating a shunt (a through-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 the expandable body is expanded, defining a receiving space capable of receiving biological tissue. The electrode portion is disposed in the recess. Furthermore, the shaft portion having the expandable body at its distal end has a traction portion that can traction the expandable body to change the shape and radial position of the recess. The traction portion deforms the recess, allowing the recess to sandwich biological tissue received in the receiving space from both sides in the thickness direction. Such a medical device is disclosed, for example, in Patent Document 1.
[0004] International Publication No. 2019-085841
[0005] The expandable body is formed of a linear body, and in its natural state when not subjected to external force, is in a radially expanded state. When the medical device is inserted, the expandable body is stored in a storage sheath and in a contracted state. Once the storage sheath is inserted to the site to be treated, the storage sheath is moved toward the proximal end, exposing the expandable body and allowing it to expand.
[0006] If a torsional force is applied to the expandable body before it is exposed to the outside of the storage sheath, such as when inserting a medical device, the portion of the expandable body that will become the recess may twist, causing the linear bodies that form the recess to become tangled, which may prevent the expandable body from expanding to its original shape when it subsequently expands. Furthermore, when the expandable body twists inside the storage sheath, the linear bodies that form the expandable body may rub against each other, creating the risk that the coating on the linear bodies may peel off or that the electrode parts arranged on the linear bodies may be damaged.
[0007] The present invention has been made to solve the above-mentioned problems, and aims to provide a medical device that can prevent the recessed portion of the expansion body from shifting circumferentially and twisting, even if a torsional force is applied when the expansion body contracts.
[0008] (1) A medical device according to the present invention that achieves the above-mentioned object is a medical device comprising: an expandable body made of a plurality of linear bodies, having a central axis, and capable of radially expanding from a contracted state to an expanded state by a self-expansion force; a long, hollow shaft portion connected to a base end of the expandable body; and a long traction portion inserted into the shaft portion and movable along the axial direction of the shaft portion, wherein the expandable body has a recess that is recessed radially inward in the expanded state, and the recess has a bottom portion located at the innermost radial position, a base end side upright portion extending from the base end of the bottom portion toward a base end side apex on the radially outer side, and a tip end side upright portion extending from the tip end of the bottom portion toward a tip end side apex on the radially outer side, and the shaft portion is the distal end of the expansion body is in contact with the inner surface of the expansion body between the base end and the tip end of the expansion body, and the distal end of the expansion body is in contact with the inner surface of the expansion body between the base end apex and the tip of the bottom end of the expansion body, and the distal end of the distal end of the expansion body is in contact with the inner surface of the expansion body between the base end apex and the tip of the bottom end of the expansion body, and the traction portion is inserted into the distal end of the expansion body and extends from the tip end of the expansion body so as to be exposed to the outside and connectable to the expansion body so as to apply a traction force to the expansion body that changes the shape and radial position of the recess. The distal end of the tip end extension is located distal to the bottom of the expansion body in the expanded state and proximal to the tip of the expansion body, and the distal end extension is in contact with the inner surface of the expansion body between the base end apex and the tip of the bottom end in the contracted state.
[0009] In the medical device (1) configured as described above, in the contracted state, the distal extension portion extends so as to contact the inner surface of the expandable body from the base end apex to the tip of the base portion, so that when a torsional force is applied to the expandable body in the contracted state, the distal extension portion limits circumferential displacement of the linear body forming the expandable body and suppresses twisting of the recess of the expandable body. As a result, the medical device can prevent the expandable body from being unable to expand to its original shape, peeling of the coating applied to the linear body, and damage to the electrode portion.
[0010] (2) In the medical device of (1), the expandable body may have a distal inclined portion extending from the distal apex toward the distal end of the expandable body, and the distal end of the expandable body may have a converging portion where the plurality of linear members forming the distal inclined portion converge. This allows the distal extension portion to suppress twisting of the recess in the medical device when the expandable body has a shape that is prone to twisting.
[0011] (3) In the medical device of (1) or (2) above, the medical device may be used together with a sheath through which the shaft portion can be inserted and which can house the expandable body so that the expandable body is in the contracted state, and when the expandable body is housed in the sheath and in the contracted state, the base end apex and the distal end apex may be configured to contact the inner surface of the sheath and the bottom end may be configured to be spaced apart from the inner surface of the sheath. This allows the medical device to limit circumferential displacement of the linear body and suppress twisting of the recessed portion of the expandable body when the expandable body is housed in the sheath.
[0012] (4) In any of the medical devices (1) to (3) above, the distal end of the distal extension portion may be located proximal to the bottom of the expandable body in the contracted state and distal to the base-side apex of the expandable body, and may be configured to contact the inner surface of the base-side upright portion at a point where the outer diameter of the expandable body gradually decreases toward the bottom in the contracted state. This allows the shaft portion to be prevented from being located inside the bottom, which is the radially innermost portion of the expandable body, making it easier to contract the expandable body and store it.
[0013] (5) In any of the medical devices (1) to (4) above, the tip of the distal extension may be located directly below the radially innermost position of the base of the expandable body in the contracted state and may be in contact with the inner surface of the base of the expandable body. This allows the distal extension to further restrict circumferential displacement of the linear body that forms the recess, thereby effectively suppressing twisting of the expandable body.
[0014] (6) In any of the medical devices (1) to (5) above, the traction section may have a traction shaft inserted into the shaft section and movable along the axial direction of the shaft section, the traction shaft being exposed from the inside of the distal extension section to the outside, extending distally beyond the distal end of the expandable body, and moving proximally relative to the shaft section to couple to the distal end of the expandable body, compressing the expandable body in the axial direction and applying a traction force to the expandable body that changes the shape and radial position of the recess. This allows the medical device to reliably suppress twisting of the expandable body in a structure in which the expandable body is compressed by pulling the distal end of the expandable body toward the proximal end with the traction shaft, thereby gripping biological tissue with the recess.
[0015] (7) In the medical device of (6) above, the expansion body has a distal rigid portion extending from the distal end of the expansion body toward the inside of the expansion body, and both the distal extension portion and the distal rigid portion are more rigid than the traction shaft, and in the expanded state, the traction shaft is exposed to the outside between the distal extension portion and the distal rigid portion, and is configured to be connected to the distal end of the expansion body and to change the shape and radial position of the recess by pulling the distal rigid portion toward the distal extension portion, and in the expanded state, the distance between the base end apex and the distal end apex in the axial direction along the central axis may be approximately the same as the length along the axial direction of the traction shaft exposed between the distal extension portion and the distal rigid portion. As a result, when the traction shaft is pulled and the base end apex and the tip end apex come into contact, the rigid tip extension portion and the tip rigid portion come into contact, restricting further traction and preventing damage to the expansion body due to strong contact between the base end apex and the tip end apex.
[0016] 1 is a front view showing the overall configuration of a medical device according to an embodiment. FIG. 1 is an enlarged perspective view of the vicinity of the expansion body of the medical device. FIG. 2 is an enlarged front view of the vicinity of the expansion body of the medical device. FIG. 3 is an enlarged front view of the vicinity of the distal end of the medical device in a state in which the expansion body is housed in a housing sheath. FIG. 4 is an enlarged front view of the vicinity of the distal end of the expansion body placed in a through-hole, with the distal end side exposed from the housing sheath. FIG. 5 is an enlarged front view showing the state in which the expansion body grips biological tissue. FIG. 6 is an explanatory diagram schematically showing the state in which the expansion body is placed in the atrial septum, with the medical device in a front view and the biological tissue in a cross-sectional view. FIG. 7 is an enlarged front view of the vicinity of the distal end of the medical device in a state in which the expansion body is housed in a housing sheath, with the distal end of the shaft portion positioned at the bottom of the recess of the contracted expansion body.
[0017] 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."
[0018] The medical device in the following embodiments is configured to expand a through hole Hh formed in the atrial septum HA of a patient's heart H, and to perform a maintenance procedure to maintain the expanded through hole Hh at that size.
[0019] 1 and 2, the medical device 10 of this embodiment has a long, hollow shaft portion 20, an expansion body 21 provided at the distal end of the shaft portion 20, and a handheld operation portion 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. The expansion body 21 is formed of a linear body 50, and in its natural state when not subjected to external force, is in a radially expanded state due to its own expansion force.
[0020] The shaft portion 20 has a storage sheath 25 provided on the outermost periphery. The expansion body 21 is movable axially back and forth 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 stored in the storage sheath 25 is in a contracted state. By moving the storage sheath 25 toward the proximal end from a state in which the expansion body 21 is stored, the expansion body 21 can be exposed to the outside and expanded.
[0021] A traction shaft 26 is disposed inside the shaft portion 20 as a traction portion 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 portion 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, 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 end member 35.
[0022] The tip member 35, to which the tip end of the traction shaft 26 is fixed, is not fixed to the expansion body 21. As a result, the traction shaft 26 slides axially relative to the shaft portion 20 toward the proximal end, and the tip member 35 can thereby 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.
[0023] 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.
[0024] 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.
[0025] 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.
[0026] 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.
[0027] As shown in Figure 3, the shaft portion 20 has a hollow distal extension portion 30 at its distal end that extends into the expandable body 21. The distal extension portion 30 extends from the base end of the expandable body 21 to partway along the central axis of the expandable body 21. When the expandable body 21 is in a radially expanded state, the distal position A1 of the distal extension portion 30 in the longitudinal direction is located further distal than the bottom 51a of the recess 51. The shaft portion 20 also has a connecting portion 57 that is connected to the base end of the expandable body 21.
[0028] The traction shaft 26 is inserted into the interior of the distal extension portion 30 that constitutes the shaft portion 20, protrudes from the distal end of the distal extension portion 30, passes through the interior of the expansion body 21, and extends from the distal end of the expansion body 21 to the distal end member 35 so as to apply a traction force to the expansion body 21 that changes the shape and radial position of the recess 51. The distal end of the traction shaft 26 is fixed to the distal end member 35.
[0029] The distal end of the expandable body 21 is provided with a distal rigid portion 31 extending from the distal end toward the interior of the expandable body 21. Both the distal extension portion 30 and the distal rigid portion 31 are more rigid than the flexible traction shaft 26. The traction shaft 26 passes through the interior of the distal extension portion 30 and the distal rigid portion 31, respectively, and the portion between the distal extension portion 30 and the distal rigid portion 31 is exposed to the outside. Since the expandable body 21 has the distal rigid portion 31, when the biological tissue around the puncture hole Hh has a circumferentially varying thickness, the traction shaft 26 can bend in accordance with the thickness of the biological tissue, and the recess 51 of the expandable body 21 can be closely attached to the biological tissue over the entire circumferential direction. Furthermore, the distance between the base end apex 51c and the distal end apex 51d in the axial direction along the central axis of the expandable body 21 is approximately the same as the axial length of the traction shaft 26 exposed between the distal extension portion 30 and the distal rigid portion 31.
[0030] The expandable body 21 has multiple linear bodies 50 in the circumferential direction. The linear bodies 50 branch and merge along the length direction to form a mesh-like structure. This allows the expandable body 21 to expand and contract radially. The base ends of the linear bodies 50 extend from connecting portions 57 toward the distal end. The distal ends of the linear bodies 50 extend from distal convergent portions 58 toward the base end. When the expandable body 21 is in an expanded state, the linear bodies 50 have a base-side inclined portion 55 that is inclined so as to increase radially from the connecting portions 57 toward the center, and a distal-side inclined portion 56 that is inclined so as to increase radially from the distal convergent portions 58 toward the center.
[0031] The linear body 50 has a recess 51 in its axial center, recessed radially inward of the expandable body 21 in its expanded state. The radially innermost portion of the recess 51 is a bottom 51a. The recess 51 has a base-side upright portion 51e extending from the base end of the bottom 51a to a base-side apex 51c on the radially outer side, and a distal-side upright portion 51f extending from the tip of the bottom 51a to a distal-side apex 51d on the radially outer side. The bottom 51a is the range where the linear body 50 bends radially innermost in the extension direction of the linear body 50, and the base-side upright portion 51e and the distal-side upright portion 51f are the range where the linear body 50 extends linearly in the extension direction of the linear body 50. The recess 51 defines a receiving space 51b that can receive biological tissue when the expandable body 21 is expanded.
[0032] When the traction shaft 26 slides relative to the shaft portion 20 in the proximal direction and a compressive force is applied to the expansion body 21, the distal upright portion 51f and the proximal upright portion 51e approach each other and come into close contact with the biological tissue received in the receiving space 51b. The proximal upright portion 51e has an electrode portion 22 arranged along the recess 51 so as to face the receiving space 51b. That is, the electrode portion 22 is provided along the expansion body 21 at a middle portion in the central axial direction of the expansion body 21. In this embodiment, ten electrode portions 22 are provided along the circumferential direction. The electrode portion 22 may also be arranged on the distal upright portion 51f.
[0033] 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.
[0034] 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.
[0035] As shown in Fig. 4, the expandable body 21 stored inside the storage sheath 25 is in a contracted state. In this state, the distal end position A2 in the longitudinal direction of the distal extension portion 30 constituting the shaft portion 20 is located near the bottom portion 51a of the expandable body 21. More specifically, when the expandable body 21 is contracted, the distal end position A2 in the longitudinal direction of the distal extension portion 30 is located closer to the base end than the radially innermost position of the bottom portion 51a, and contacts the inner surface of the expandable body 21 between the base-end apex 51c and the tip of the bottom portion 51a. If the distal end position A2 in the longitudinal direction of the distal extension portion 30 is located near the bottom portion 51a when the expandable body 21 is contracted, then when the expandable body 21 is expanded, the distal end position A1 in the longitudinal direction of the distal extension portion 30 is located closer to the distal end of the bottom portion 51a and closer to the base end than the tip of the expandable body 21, as shown in Fig. 3. When the expandable body 21 is expanded, the distal end position A1 in the longitudinal direction of the distal extension portion 30 is located distal to the bottom portion 51a, and therefore an axis extending from the base end of the expandable body 21, past the bottom portion 51a, to the distal end exists inside the expandable body 21. This makes it difficult for the base end side of the expanded expandable body 21 to bend relative to the bottom portion 51a, and the electrode portion 22 arranged along the proximal upright portion 51e can be reliably pressed against biological tissue.
[0036] When the expandable body 21 is contracted, the tip position A2 in the longitudinal direction of the tip extension portion 30 needs to be located near the bottom portion 51a, and may be located within the range of the bottom portion 51a or within the range of the base-side upright portion 51e in the extension direction of the linear body 50. The tip position A2 in the longitudinal direction of the tip extension portion 30 may be located at the boundary between the bottom portion 51a and the base-side upright portion 51e in the extension direction of the linear body 50.
[0037] In the expansion body 21, the linear bodies 50 distal to the recess 51 extend to the distal convergence portion 58, and the distal end is closed. Therefore, when a force acts in a twisting direction between the distal end and the base end of the expansion body 21, the linear bodies 50 are likely to twist while rubbing against each other at the recess 51. In the medical device 10 of this embodiment, when the expansion body 21 is contracted, the distal end position A2 in the longitudinal direction of the distal extension portion 30 is located near the bottom 51 a of the expansion body 21, and the distal extension portion 30 extends to the vicinity of the bottom 51 a, so that the distal extension portion 30 can prevent the linear bodies 50 from twisting. Furthermore, because twisting of the linear bodies 50 can be prevented, rubbing against each other between the linear bodies 50 can be prevented, and peeling of the coating applied to the surface of the linear bodies 50 and damage to the electrode portion 22 can be prevented.
[0038] When the expandable body 21 is housed in the storage sheath 25 and in a stored state, the base-side apex 51c and the tip-side apex 51d contact the inner surface of the storage sheath 25, and the bottom 51a is separated from the inner surface of the storage sheath 25. At this time, the tip of the tip extension portion 30 contacts the inner surface of the base-side upright portion 51c at a location where the outer diameter of the expandable body 21 gradually decreases toward the bottom 51a. In other words, the shaft portion 20 is not located inside the bottom 51a, where the expandable body 21 is located at the radially innermost position. This makes it easy to contract the expandable body 21 and store it.
[0039] 5, when the expandable body 21 is contracted, the tip position A2 in the longitudinal direction of the tip extension portion 30 is located directly below the radially innermost position of the bottom portion 51a, and may be configured to contact the inner surface of the bottom portion 51a of the expandable body 21. This further restricts circumferential displacement of the linear body 50 at the position of the bottom portion 51a, thereby more effectively suppressing twisting of the expandable body 21.
[0040] When using the medical device 10, a through-hole Hh is first formed at the position of the fossa ovalis in the atrial septum HA using a puncture device. The medical device 10 performs a procedure to expand the through-hole Hh and cauterize the edges of the through-hole Hh, thereby maintaining the expanded through-hole Hh at its original size. As shown in Fig. 4 , 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 containment sheath 25 is inserted up to the atrial septum HA so that the expandable body 21 is positioned at the position of the pre-formed through-hole Hh. The distal end of the containment sheath 25 penetrates the atrial septum HA and reaches the left atrium HLa.
[0041] When the medical device 10 is inserted, the expandable body 21 is stored in the storage sheath 25 and is in a contracted state. When the storage sheath 25 has penetrated the atrial septum HA, the storage sheath 25 is moved proximally, thereby exposing and expanding the portion of the expandable body 21 distal to the recess 51, as shown in Fig. 7. Even if a twisting force acts on the expandable body 21 when the medical device 10 is inserted, twisting of the expandable body 21 is suppressed because the distal extension portion 30 extends to the vicinity of the bottom 51a of the recess 51 as described above, and poor deployment of the expandable body 21 due to twisting can be suppressed.
[0042] When the storage sheath 25 is moved further toward the base end and the entire expansion body 21 is exposed, the portion of the expansion body 21 that is proximal to the recess 51 also expands radially, and the recess 51 is positioned in the through hole Hh in the atrial septum HA, and the receiving space 51b receives the biological tissue surrounding the through hole Hh.
[0043] As shown in Figure 8, by moving the traction shaft 26 toward the proximal end 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 in the axial direction. The atrial septum HA is grasped by the proximal upright portion 51e and the distal upright portion 51f that form the recess 51, and the electrode portion 22 is pressed against the biological tissue. The fossa ovalis, where the through-hole Hh 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 by squeezing it. At this time, the distal end of the distal extension portion 30 and the proximal end of the distal rigid portion 31 are close to each other. The distal position of the distal extension portion 30 in the longitudinal direction is set so that it does not extend beyond the bottom portion 51a toward the distal end when the expandable body 21 is contracted, so as not to interfere with the proximal end of the distal rigid portion 31 when the expandable body 21 is clamped against the biological tissue.
[0044] With the electrode portion 22 pressed against the biological tissue, the edge of the through-hole Hh can be cauterized (heated and cauterized) by the high-frequency energy by applying high-frequency energy to the edge of the through-hole Hh through the electrode portion 22. The high-frequency energy is applied by applying a voltage between a pair of circumferentially adjacent electrode portions 22. This inhibits the through-hole Hh from closing due to natural healing and maintains its size.
[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 through-hole Hh based on the displayed image.
[0046] As described above, the medical device 10 according to the present embodiment (1) is a medical device 10 including: an expandable body 21 made of a plurality of linear bodies 50, having a central axis, and capable of radially expanding from a contracted state to an expanded state by a self-expansion force; a long, hollow shaft portion 20 connected to a base end of the expandable body 21; and a long traction portion 26 inserted into the shaft portion 20 and movable along the axial direction of the shaft portion 20. The expandable body 21 has a recess 51 recessed radially inward in the expanded state, and the recess 51 has a bottom portion 51a located at the innermost radial position; a base-side upright portion 51e extending from the base end of the bottom portion 51a toward a base-side apex 51c on the radially outer side; and a tip-side upright portion 51d extending from the tip of the bottom portion 51a toward a tip-side apex 51d on the radially outer side. f, the shaft portion 20 has a connecting portion 57 connected to the base end of the expansion body 21, and a hollow tip extension portion 30 extending along the central axis from the connecting portion 57 toward the tip end of the expansion body 21 within the expansion body 21, the traction portion 26 is inserted into the tip extension portion 30 and extends exposed to the outside from the tip extension portion 30 so as to be connectable to the expansion body 21 so as to apply a traction force to the expansion body 21 that changes the shape and radial position of the recess 51, the tip of the tip extension portion 30 is located distal to the bottom 51a of the expansion body 21 in the expanded state and proximal to the tip of the expansion body 21, and the tip extension portion 30 contacts the inner surface of the expansion body 21 between the base end apex 51c and the tip of the bottom 51a in the contracted state. In the medical device 10 configured in this manner, in the contracted state, the distal extension portion 30 extends so as to contact the inner surface of the expandable body 21 from the base-side apex 51c to the tip of the bottom portion 51a, so that when a torsional force acts on the expandable body 21 in the contracted state, the circumferential displacement of the linear body 50 forming the expandable body 21 is limited, and twisting at the recess 51 of the expandable body 21 can be suppressed. Therefore, the medical device 10 can suppress the expandable body 21 from being unable to expand to its original shape, peeling of the coating applied to the linear body 50, and damage to the electrode portion.
[0047] (2) In the medical device 10 described in (1) above, the expandable body 21 may have a distal inclined portion 56 extending from the distal apex 51d toward the distal end of the expandable body 21, and the distal end of the expandable body 21 may have a distal convergent portion 58 where the multiple linear bodies 50 forming the distal inclined portion 56 converge. This allows the medical device 10 to suppress twisting at the recess 51 by the distal extension portion 30 when the expandable body 21 has a shape that is prone to twisting.
[0048] (3) In the medical device 10 described in (1) or (2) above, the medical device 10 is used together with a sheath 25 through which the shaft portion 20 can be inserted and which can house the expansion body 21 so that the expansion body 21 is in a contracted state, and when the expansion body 21 is housed in the sheath 25 and in a contracted state, the base end apex 51 c and the tip end apex 51 d may be configured to contact the inner surface of the sheath 25, and the bottom 51 a may be configured to be separated from the inner surface of the sheath 25. This allows the medical device 10 to limit circumferential displacement of the linear body 50 and suppress twisting of the recess 51 of the expansion body 21 when the expansion body 21 is housed in the sheath 25.
[0049] (4) In any of the medical devices 10 described above in (1) to (3), the distal end of the distal extension 30 may be located proximal to the bottom 51a of the expandable body 21 in the contracted state and distal to the base-side apex 51c of the expandable body 21, and may be configured to contact the inner surface of the base-side upright portion 51c at a point where the outer diameter of the expandable body 21 gradually decreases toward the bottom 51a in the contracted state. This makes it easier to contract the expandable body 21 and store the expandable body 21, because the shaft 20 is not located inside the bottom 51a, where the expandable body 21 is located at its radially innermost position.
[0050] (5) In any of the medical devices 10 described above in (1) to (4), the tip of the distal extension 30 may be located directly below the radially innermost position of the bottom 51 a of the expandable body 21 in the contracted state, and may be in contact with the inner surface of the bottom 51 a of the expandable body 21. This allows the distal extension 30 of the medical device 10 to further restrict circumferential displacement of the linear body 50 that forms the recess 51, thereby effectively suppressing twisting of the expandable body 21.
[0051] (6) In any of the medical devices 10 described above in (1) to (5), the traction section 26 may have a traction shaft 26 inserted into the shaft section 20 and movable along the axial direction of the shaft section 20, the traction shaft 26 being exposed from the inside of the distal extension section 30 to the outside, extending from the distal end of the expansion body 21 to the distal side, and moving relative to the shaft section 20 in the proximal direction, thereby connecting to the distal end of the expansion body 21 and compressing the expansion body 21 in the axial direction, and applying a traction force to the expansion body 21 that changes the shape and radial position of the recess 51. In this way, the medical device 10 can reliably suppress twisting of the expansion body 21 in a structure in which the expansion body 21 is compressed and the recess 51 grasps biological tissue by pulling the distal end of the expansion body 21 toward the proximal end with the traction shaft 26.
[0052] (7) In the medical device 10 of (6) above, the expansion body 21 has a distal rigid portion 31 extending from the distal end of the expansion body 21 toward the interior of the expansion body 21, and both the distal extension portion 30 and the distal rigid portion 31 are more rigid than the traction shaft 26. In the expanded state, the traction shaft 26 is exposed to the outside between the distal extension portion 30 and the distal rigid portion 31, and is configured to change the shape and radial position of the recess 51 by connecting to the distal end of the expansion body 21 and pulling the distal rigid portion 31 toward the distal extension portion 30. In the expanded state, the distance between the base end apex 51c and the distal end apex 51d in the axial direction along the central axis may be approximately the same as the length along the axial direction of the traction shaft 26 exposed between the distal extension portion 30 and the distal rigid portion 31. As a result, when the traction shaft 26 of the medical device 10 is pulled and the base end apex 51c and the tip end apex 51d come into contact, the rigid tip extension portion 30 comes into contact with the tip rigid portion 31, thereby restricting further pulling and preventing damage to the expansion body 21 due to strong contact between the base end apex 51c and the tip end apex 51d.
[0053] 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 concept of the present invention. In the above-described embodiment, the traction unit is the traction shaft 26, but the traction unit may be a mechanism other than this, such as a wire connected to the bottom 51 a of the recess 51.
[0054] This application is based on Japanese Patent Application No. 2023-163537 filed on September 26, 2023, the disclosures of which are incorporated herein by reference in their entirety.
[0055] REFERENCE SIGNS LIST 10 Medical device 11 Guide wire 20 Shaft portion 21 Expansion body 22 Electrode portion 23 Proximal operation portion 25 Storage sheath 26 Traction shaft (traction portion) 27 Bending portion 30 Tip extension portion 31 Tip rigid portion 35 Tip member 40 Housing 41 Operation dial 42 Conversion mechanism 50 Linear body 51 Recess 51a Bottom portion 51b Receiving space 51c Base end side apex 51d Tip end side apex 51e Base end side standing portion 51f Tip end side standing portion 55 Base end side inclined portion 56 Tip end side inclined portion 57 Connection portion 58 Tip convergence portion
Claims
1. A medical device comprising: an expansion body consisting of a plurality of linear bodies, having a central axis, and capable of radially expanding from a contracted state to an expanded state by a self-expansion force; a long, hollow shaft portion connected to a base end of the expansion body; and a long traction portion inserted inside the shaft portion and movable along the axial direction of the shaft portion, wherein the expansion body has a recess that is recessed radially inward in the expanded state, and the recess has a bottom portion located at the innermost radial position, a base end upright portion extending from the base end of the bottom portion toward a base end apex on the radial outside, and a tip end upright portion extending from the tip of the bottom portion toward a tip end apex on the radial outside, and the shaft portion has a connecting portion connected to the base end of the expansion body, and a hollow tip extension portion extending along the central axis inside the expansion body from the connecting portion toward the tip end of the expansion body, The traction portion is inserted into the inside of the tip extension portion and extends from the tip extension portion to be exposed to the outside and connectable to the expansion body so as to apply a traction force to the expansion body that changes the shape and radial position of the recess, the tip of the tip extension portion is located distal to the bottom of the expansion body in the expanded state and proximal to the tip of the expansion body, and the tip extension portion contacts the inner surface of the expansion body between the base end apex and the tip of the bottom in the contracted state.
2. The medical device of claim 1, wherein the expandable body has a tip-side inclined portion extending from the tip-side apex toward the tip end of the expandable body, and the tip end of the expandable body has a converging portion where the multiple linear bodies forming the tip-side inclined portion converge.
3. The medical device according to claim 1 or 2, which is used together with a sheath through which the shaft portion can be inserted and which can store the expansion body so that the expansion body is in the contracted state, and which is configured such that when the expansion body is stored within the sheath and in the contracted state, the base end apex and the tip end apex contact the inner surface of the sheath and the bottom is spaced apart from the inner surface of the sheath.
4. A medical device as described in claim 1 or 2, wherein the tip of the tip extension portion is located base side of the bottom of the expansion body in the contracted state and tip side of the base side apex of the expansion body, and in the contracted state, contacts the inner surface of the base side upright portion at a point where the outer diameter of the expansion body gradually decreases toward the bottom.
5. A medical device as described in claim 1 or 2, wherein the tip extension is located directly below the radially innermost position of the base of the expandable body in the contracted state and contacts the inner surface of the base of the expandable body.
6. The medical device described in claim 1 or 2, wherein the traction portion has a traction shaft that is inserted into the inside of the shaft portion and is movable along the axial direction of the shaft portion, the traction shaft being exposed from the inside of the tip extension portion to the outside, extending beyond the tip of the expansion body to the tip side, and moving in the base end direction relative to the shaft portion, thereby connecting to the tip portion of the expansion body and compressing the expansion body in the axial direction, and applying a traction force to the expansion body that changes the shape and radial position of the recess.
7. The medical device of claim 6, wherein the expansion body has a tip rigid portion extending from the tip of the expansion body toward the inside of the expansion body, the tip extension portion and the tip rigid portion are both more rigid than the traction shaft, and in the expanded state, the traction shaft is exposed to the outside between the tip extension portion and the tip rigid portion and is configured to be connected to the tip of the expansion body and to change the shape and radial position of the recess by pulling the tip rigid portion toward the tip extension portion, and in the expanded state, the distance between the base end apex and the tip end apex in the axial direction along the central axis is approximately the same as the length along the axial direction of the traction shaft exposed between the tip extension portion and the tip rigid portion.
Citation Information
Patent Citations
Medical device and method
JP2022042115A
Medical device
WO2021065873A1
Medical device
WO2023167125A1