Medical device

Abstract

A medical device 100 comprises: a cylindrical shaft 10 having a hollow part 10p extending in the axial direction; an elongated operation wire 20 inserted into the hollow part 10p of the shaft 10; an annular elastic member 40 disposed in a gap 30 between an outer peripheral part 20a of the operation wire 20 and an inner peripheral part 10b of the shaft 10; and a cylindrical insertion member 50 disposed in the gap 30 so as to abut on the elastic member 40 from the base end side of the medical device 100. The inner diameter 501d1 of the distal end 501 of the insertion member 50 is larger than the inner diameter 40d1 of the elastic member 40, and the outer diameter 501d2 of the distal end 501 of the insertion member 50 is smaller than the outer diameter 40d2 of the elastic member 40. Such a medical device is suitable for suppressing leakage of fluid.

Description

Medical Devices

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to medical devices, and more particularly to catheter-like medical devices.

[0002] Conventionally, catheter-like medical devices for insertion into tubular organs of the human body, such as blood vessels and digestive organs, have been known that include a cylindrical shaft and a control wire inserted inside the shaft. The control wire moves axially inside the shaft. Examples of such medical devices include basket catheters and balloon catheters.

[0003] For example, basket catheters are used in endoscopic treatment of choledocholithiasis to break up and remove stones from the bile duct. Generally, a basket catheter includes a cylindrical shaft, a control wire inserted into the shaft, an expandable basket attached to the distal end of the control wire, and an injection port for introducing a fluid such as a contrast agent into the shaft (see, for example, Patent Documents 1 and 2). In a basket catheter, the basket can be expanded or retracted into the shaft by moving the control wire in the axial direction. A sealing member such as an O-ring is disposed inside the basket catheter to prevent leakage of a fluid such as a contrast agent. The degree of adhesion between the sealing member and other members inside the basket catheter affects fluid leakage.

[0004] International Publication No. 2019 / 244463 Japanese Patent Application Laid-Open No. 2002-34899

[0005] Conventional medical devices, such as those described in Patent Documents 1 and 2, in which an operating wire moves axially inside a shaft, have room for improvement in terms of suppressing leakage of fluids such as contrast media.

[0006] The present disclosure has been made in consideration of the above circumstances, and aims to provide a medical device suitable for suppressing fluid leakage.

[0007] In order to achieve the above-mentioned object, the present disclosure provides a medical device (Disclosure 1) comprising: a cylindrical shaft having a hollow portion extending in the axial direction; a long operating wire inserted into the hollow portion of the shaft; an annular elastic member disposed in the gap between the outer periphery of the operating wire and the inner periphery of the shaft; and a cylindrical insertion member disposed in the gap so as to abut against the elastic member from the base end side of the medical device, wherein the inner diameter of the tip of the insertion member is larger than the inner diameter of the elastic member and the outer diameter of the tip of the insertion member is smaller than the outer diameter of the elastic member.

[0008] According to this disclosure (Disclosure 1), the contact (abutment) area between the tip of the insertion member and the elastic member is small, so when the insertion member is pushed into the gap so that the tip of the insertion member abuts against the elastic member, the pressing force per unit area acting on the elastic member increases. As a result, the tip of the insertion member is pushed firmly into the elastic member, improving the adhesion between the elastic member and the insertion member and making it less likely for the elastic member to slip. As a result, the effectiveness of suppressing leakage of fluids such as contrast media in medical devices can be improved.

[0009] In the above disclosure (Disclosure 1), it is preferable that the tip of the insertion member is located inside the contour of the elastic member in a radial cross section (Disclosure 2).

[0010] According to this disclosure (Disclosure 2), the adhesion between the elastic member and the insertion member can be further improved.

[0011] In the above disclosures (Disclosures 1 and 2), it is preferable that the thickness of the distal end of the insertion member is smaller than the thickness of the proximal end of the insertion member in an axial cross section (Disclosure 3).

[0012] According to this disclosure (Disclosure 3), it is possible to improve the adhesion between the elastic member and the insert member while ensuring the strength of the insert member.

[0013] In the above disclosure (Disclosure 3), the insertion member may have a tapered portion whose thickness decreases from the base end side toward the tip end side in an axial cross section (Disclosure 4).

[0014] According to this disclosure (Disclosure 4), it is possible to achieve an excellent balance between the strength of the insert member and the adhesion between the elastic member and the insert member.

[0015] In the above disclosures (Disclosures 1-4), the tip of the insertion member may have a flat portion that abuts against the elastic member (Disclosure 5).

[0016] According to this disclosure (Disclosure 5), the pressing force of the insertion member can be reliably applied to the elastic member.

[0017] In the above disclosures (Disclosures 1-4), the tip of the insertion member may have a curved surface portion that abuts against the elastic member (Disclosure 6).

[0018] According to this disclosure (Disclosure 6), the pressing force of the insertion member can be reliably applied to the elastic member.

[0019] In the above disclosures (Disclosures 1-6), it is preferable that the shaft has a radially extending annular abutment surface, and the elastic member is arranged axially between the abutment surface and the tip of the insertion member (Disclosure 7).

[0020] The operating wire moves in the axial direction while sliding on the elastic member in the hollow portion of the shaft. According to this disclosure (Disclosure 7), by pressing the tip of the insertion member against the abutment surface, the elastic member is supported between the abutment surface and the tip of the insertion member, so that it is possible to avoid axial displacement of the elastic member while ensuring close contact between the elastic member and the insertion member.

[0021] According to the present disclosure, the contact (abutment) area between the tip of the insertion member and the elastic member is small, so that the pressing force per unit area acting on the elastic member increases, and the tip of the insertion member is pressed in by the elastic member. This improves the adhesion between the elastic member and the insertion member, making the elastic member less likely to slip, thereby improving the effect of suppressing leakage of fluids such as contrast medium in the medical device.

[0022] Fig. 1A is a longitudinal sectional view showing a schematic structure of a medical device according to an embodiment of the present disclosure. Fig. 1B is a sectional view taken along line IB-IB of Fig. 1A. Fig. 1C is a longitudinal sectional view showing a schematic structure of a medical device according to a modified example. Fig. 2A is a sectional view taken along line IIB-IIB of the medical device of Fig. 2A. Fig. 2B is a side view showing an example of a medical device according to an embodiment of the present disclosure.

[0023] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the embodiments described below, and the described embodiments are merely examples for explaining the technical features of the present disclosure. The shapes and dimensions shown in each drawing are shown merely to facilitate understanding of the contents of the present disclosure, and do not accurately reflect the actual shapes and dimensions.

[0024] As used herein, the term "distal side" refers to the direction along the axis X (axial direction) of the medical device, in which the medical device advances toward the target site. The term "proximal side" refers to the direction along the axis X (axial direction) of the medical device, in the opposite direction to the distal side. Unless otherwise noted, the term "distal" refers to the distal end of any component or component, and the term "proximal end" refers to the proximal end of any component or component. In the longitudinal cross-sectional views shown below, the left side of the illustration is the "distal side" that is inserted into the body, and the right side is the "proximal side" that is operated by the operator.

[0025] FIG. 1A is a longitudinal cross-sectional view showing a schematic structure of a medical device 100 according to an embodiment of the present disclosure. FIG. 1B is an IB-IB cross-sectional view of the medical device 100 of FIG. 1A. The medical device 100 according to this embodiment includes a cylindrical shaft 10 having a hollow portion 10p extending in the axial direction, a long operating wire 20 inserted into the hollow portion 10p of the shaft 10, an annular elastic member 40 disposed in a gap 30 between an outer circumferential portion 20a of the operating wire 20 and an inner circumferential portion 10b of the shaft 10, and a cylindrical insertion member 50 disposed in the gap 30 so as to abut against the elastic member 40 from the proximal end side of the medical device 100. As shown in FIGS. 1A and 1B , in the medical device 100, an inner diameter 501d1 of a distal end 501 of the insertion member 50 is larger than an inner diameter 40d1 of the elastic member 40, and an outer diameter 501d2 of the distal end 501 of the insertion member 50 is smaller than an outer diameter 40d2 of the elastic member 40.

[0026] During a treatment using the medical device 100, a fluid such as a contrast agent can be introduced from the outside into the hollow portion 10p of the shaft 10. The fluid flows along the hollow portion 10p and is discharged from the tip of the shaft 10 toward a target site such as a bile duct. Body fluids such as bile can also flow into the hollow portion 10p of the shaft 10 from the tip of the shaft 10. The elastic member 40 is arranged to prevent leakage of such fluid from the medical device 100, specifically, leakage of such fluid into the gap 30.

[0027] According to the medical device 100, the contact (abutment) area between the tip 501 of the insertion member 50 and the elastic member 40 is small, so when the insertion member 50 is pushed into the gap 30 so that the tip 501 of the insertion member 50 abuts against the elastic member 40, the pressing force per unit area acting on the elastic member 40 increases. As a result, the tip 501 of the insertion member 50 is pushed strongly into the elastic member 40, improving the adhesion between the elastic member 40 and the insertion member 50 and making it less likely for the elastic member 40 to slip. As a result, the effect of suppressing fluid leakage in the medical device 100 can be improved.

[0028] In the gap 30, the thickness of the elastic member 40 can be reduced in the axial direction due to the pressing force applied from the tip 501 of the insertion member 50. Therefore, in the medical device 100, the elastic member 40 can have a shape different from the shape of the member itself. In this embodiment, the inner diameter 40d1 and the outer diameter 40d2 of the elastic member 40 refer to the inner diameter and the outer diameter of the elastic member 40 in a state in which the tip 501 of the insertion member 50 abuts against the elastic member 40 in the gap 30.

[0029] In this embodiment, the tip 501 of the insertion member 50 refers to the portion of the tip side of the insertion member 50 that is in contact (abuts) with the elastic member 40. That is, in this embodiment, the inner diameter 501d1 and the outer diameter 501d2 of the tip 501 of the insertion member 50 refer to the inner diameter and the outer diameter of the portion of the tip side of the insertion member 50 that is in contact (abuts) with the elastic member 40.

[0030] 1B , in a radial cross-sectional view, it is preferable that a tip end 501 of the insertion member 50 is located inside the outline of the elastic member 40. With such a structure, the adhesion between the elastic member 40 and the insertion member 50 can be further improved.

[0031] 1B , in a radial cross-sectional view, it is more preferable that a center line 501L in the thickness direction at the tip 501 of the insertion member 50 overlaps with a center line 40L in the thickness direction of the elastic member 40. With this structure, the adhesion between the elastic member 40 and the insertion member 50 can be further improved.

[0032] 1A , in an axial cross-sectional view, it is preferable that a thickness 501t of a distal end 501 of the insertion member 50 is smaller than a thickness 502t of a proximal end 502 of the insertion member 50. The thickness 501t of the distal end 501 of the insertion member 50 corresponds to the difference between an outer diameter 501d2 and an inner diameter 501d1 of the distal end 501. With this structure, it is possible to improve the adhesion between the elastic member 40 and the insertion member 50 while ensuring the strength of the insertion member 50.

[0033] In this embodiment, the base end 502 of the insertion member 50 refers to the portion on the base end side of the insertion member 50 that corresponds to the tip 501 .

[0034] 1A , in an axial cross-sectional view, the insertion member 50 may have a tapered portion 51 whose thickness decreases from the base end 502 toward the tip end 501. With this structure, an excellent balance can be achieved between the strength of the insertion member 50 and the adhesion between the elastic member 40 and the insertion member 50.

[0035] When the insertion member 50 has a tapered portion 51, the tip 501 may be included in the tapered portion 51. In this case, the tip 501 corresponds to the portion of the tapered portion 51 that abuts against the elastic member 40.

[0036] In the example shown in Fig. 1A, the tapered portion 51 is present only on the tip 501 side of the insertion member 50 in the axial direction. With such a structure, the strength of the insertion member 50 can be further improved. However, the structure of the tapered portion 51 is not limited to the example shown in Fig. 1A. For example, the tapered portion 51 may be present throughout the entire insertion member 50 in the axial direction.

[0037] 1A and 1B, the tip 501 of the insertion member 50 may have a flat portion 501f that abuts against the elastic member 40. With this structure, the pressing force of the insertion member 50 can be reliably applied to the elastic member 40.

[0038] 1A , the flat surface 501f may be a surface that extends in the radial direction. That is, the flat surface 501f may be a surface that extends along a plane perpendicular to the axis X. The flat surface 501f may have a slight inclination with respect to the plane perpendicular to the axis X. For example, the flat surface 501f may have an inclination of more than 0° and not more than 3° with respect to the plane perpendicular to the axis X.

[0039] In the example shown in FIGS. 1A and 1B, the tip 501 of the insertion member 50 has a flat portion 501f that abuts against the elastic member 40. However, the shape of the tip 501 of the insertion member 50 is not limited to the example shown in FIGS. 1A and 1B. FIG. 2A is a longitudinal cross-sectional view showing the schematic structure of a medical device 200 according to a modified example. FIG. 2B is a cross-sectional view taken along line IIB-IIB of the medical device 200 of FIG. 2A. The medical device 200 shown in FIGS. 2A and 2B has the same structure as the medical device 100 shown in FIGS. 1A and 1B, except for the shape of the tip 501 of the insertion member 50. In FIGS. 2A and 2B, the same elements as those in the medical device 100 are designated by the same reference numerals and will not be described again.

[0040] 2A , the tip 501 of the insertion member 50 may have a curved surface 501g that comes into contact with the elastic member 40. With such a structure, the pressing force of the insertion member 50 can be reliably applied to the elastic member 40.

[0041] As shown in FIG. 2A, the curved surface portion 501g may be a surface that forms a convex portion that protrudes from a plane perpendicular to the axis X toward the tip side.

[0042] In the example shown in Fig. 2A, the curved surface portion 501g is a surface that forms a convex portion that protrudes toward the tip side from a plane perpendicular to the axis X. However, the shape of the curved surface portion 501g is not limited to the example shown in Fig. 2. For example, the curved surface portion 501g may be a surface that forms a plurality of convex portions that protrude toward the tip side from a plane perpendicular to the axis X. In other words, the curved surface portion 501g may be formed of an uneven surface.

[0043] 2A and 2B , when the tip 501 of the insert member 50 has a curved surface portion 501g, the inner diameter of the contact (abutment) portion between the tip 501 of the insert member 50 and the elastic member 40 can be considered to be the inner diameter 501d1 of the tip 501 of the insert member 50. The outer diameter of the contact (abutment) portion between the tip 501 of the insert member 50 and the elastic member 40 can be considered to be the outer diameter 501d2 of the tip 501 of the insert member 50. Therefore, when the tip 501 of the insert member 50 has a curved surface portion 501g, the difference between the outer diameter 501d2 and the inner diameter 501d1 of the tip 501 can be considered to be the thickness 501t of the tip 501 of the insert member 50.

[0044] In this embodiment, the shaft 10 is composed of a first portion 101 in which the elastic member 40 and the insertion member 50 are to be disposed, and a second portion 102 other than the first portion 101. The first portion 101 is located closer to the base end than the second portion 102. The inner diameter of the first portion 101 is larger than the inner diameter of the second portion 102. With this structure, a gap 30 is secured in the first portion 101 between the outer periphery 20a of the operating wire 20 and the inner periphery 10b of the shaft 10.

[0045] In this embodiment, the shaft 10 has an annular abutment surface 10s extending in the radial direction between the first portion 101 and the second portion 102. The abutment surface 10s is an annular surface extending along a plane perpendicular to the axis X. The elastic member 40 is preferably disposed axially between the abutment surface 10s and the tip 501 of the insert member 50. With this structure, the tip 501 of the insert member 50 is pressed against the abutment surface 10s, thereby supporting the elastic member 40 between the abutment surface 10s and the tip 501 of the insert member 50. This ensures close contact between the elastic member 40 and the insert member 50 while preventing the elastic member 40 from sliding in the axial direction.

[0046] The shaft 10 is primarily made of a resin material. Examples of materials that can be used to form the shaft 10 include polyacetal, ABS resin, and polypropylene. Because the distal end of the shaft 10 requires flexibility, the distal end of the shaft 10 may be made of a relatively flexible resin material other than those mentioned above. Examples of such resin materials include polyurethane, polyimide, polyolefin, nylon, and fluorine-based resin. Alternatively, the distal end of the shaft 10 may be made of a material other than a resin, such as a flexible coil.

[0047] The manipulation wire 20 is a wire for manipulating a member attached to the distal end of the medical device 100. For example, if the medical device 100 is a basket catheter, by moving the manipulation wire 20 in the axial direction, an expandable basket attached to the distal end of the manipulation wire 20 can be expanded or retracted into the hollow portion 10p of the shaft 10.

[0048] The operation wire 20 is made of an elastic material, such as a stainless steel alloy (SUS304, SUS316, etc.), a superelastic alloy such as a Ni-Ti alloy, a piano wire, a nickel-chromium alloy, a cobalt alloy, or tungsten.

[0049] The elastic member 40 is typically an O-ring. The elastic member 40 prevents fluid from leaking from the medical device 100.

[0050] The insert member 50 is mainly made of a resin material. Examples of materials that can be used to form the insert member 50 include polyacetal, ABS resin, and polypropylene. The insert member 50 may be made of the same material as the material that forms the shaft 10.

[0051] 1A , the medical device 100 may further include an annular stopper portion 60 connected to the proximal end 502 of the insertion member 50. The stopper portion 60 can prevent the insertion member 50 from being pushed too far into the gap 30 of the shaft 10. The outer diameter of the stopper portion 60 may be larger than the outer diameter of the proximal end 502 of the insertion member 50. That is, the stopper portion 60 may have a flange shape. The flange shape of the stopper portion 60 may catch on the proximal end of the shaft 10, thereby preventing the insertion member 50 from being pushed too far into the gap 30 of the shaft 10.

[0052] The stopper portion 60 may be molded integrally with the insertion member 50, or may be bonded to the base end 502 of the insertion member 50 using an adhesive or the like.

[0053] 3 is a side view showing an example of the medical device 100 according to this embodiment. In the example shown in FIG. 3, the medical device 100 is a basket catheter 1000.

[0054] The basket catheter 1000 is used primarily for endoscopic treatment of choledocholithiasis to break up and remove stones from the bile duct. The basket catheter 1000 includes a cylindrical shaft 10 having an axially extending hollow portion 10p, a long operating wire 20 (not shown in FIG. 3 ) inserted into the hollow portion 10p of the shaft 10, an annular elastic member 40 (not shown in FIG. 3 ) disposed in a gap 30 between an outer periphery 20a of the operating wire 20 and an inner periphery 10b of the shaft 10, and a cylindrical insertion member 50 (not shown in FIG. 3 ) disposed in the gap 30 from the proximal end side of the basket catheter 1000 so as to abut against the elastic member 40. In the basket catheter 1000, an inner diameter 501d1 of a distal end 501 of the insertion member 50 is larger than an inner diameter 40d1 of the elastic member 40, and an outer diameter 501d2 of the distal end 501 of the insertion member 50 is smaller than the outer diameter 40d2 of the elastic member 40. Such a structure improves the adhesion between the elastic member 40 and the insertion member 50, making it difficult for the elastic member 40 to slip. As a result, the effect of suppressing fluid leakage in the basket catheter 1000 can be improved.

[0055] 3, the basket catheter 1000 further includes an expandable basket 70 attached to the tip of the operating wire 20. In the basket catheter 1000, the basket 70 can be expanded or stored in the hollow portion 10p of the basket 10 by moving the operating wire 20 in the axial direction.

[0056] 3, the basket catheter 1000 further includes an injection port 80 for injecting a fluid such as a contrast agent into the hollow portion 10p of the shaft 10. The fluid introduced from the injection port 80 flows along the hollow portion 10p and is discharged into the bile duct or the like from the tip of the shaft 10. Note that the injection port 80 is connected to the second portion 102 of the shaft 10 to prevent the fluid from entering the gap 30 located in the first portion 101.

[0057] As shown in Fig. 3, the basket catheter 1000 may further include a handle portion 90 attached to the proximal end of the manipulation wire 20. The handle portion 90 may have a hollow portion extending in the axial direction, into which the manipulation wire 20 is inserted. The handle portion 90 may have a rotation mechanism that can move the manipulation wire 20 in the axial direction. The handle portion 90 may be configured to move the manipulation wire 20 in the axial direction by rotating the rotation mechanism.

[0058] While the medical device according to the present disclosure has been described above with reference to the drawings, the present disclosure is not limited to the above-described embodiments and various modifications are possible. In the above-described embodiments, a basket catheter was described as an example of a medical device according to the present disclosure. However, as long as the medical device according to the present disclosure includes a cylindrical shaft, a long operating wire inserted into the hollow portion of the shaft, and an annular elastic member disposed in the gap between the outer periphery of the operating wire and the inner periphery of the shaft, the medical device according to the present disclosure is not limited to a basket catheter. For example, the medical device according to the present disclosure may be used as a balloon catheter.

Claims

1. A medical device comprising: a cylindrical shaft having a hollow portion extending in the axial direction; a long operating wire inserted into the hollow portion of the shaft; a ring-shaped elastic member disposed in the gap between the outer periphery of the operating wire and the inner periphery of the shaft; and a cylindrical insertion member disposed in the gap so as to abut against the elastic member from the base end side of the medical device, wherein the inner diameter of the tip of the insertion member is larger than the inner diameter of the elastic member, and the outer diameter of the tip of the insertion member is smaller than the outer diameter of the elastic member.

2. The medical device according to claim 1, wherein, in a radial cross-sectional view, the tip of the insertion member is located inside the contour of the elastic member.

3. The medical device of claim 1, wherein, in an axial cross-sectional view, the thickness of the distal end of the insertion member is smaller than the thickness of the proximal end of the insertion member.

4. The medical device according to claim 3, wherein, in an axial cross-sectional view, the insertion member has a tapered portion whose thickness decreases from the base end side toward the tip end side.

5. The medical device according to claim 1, wherein the tip of the insertion member has a flat portion that abuts against the elastic member.

6. The medical device according to claim 1, wherein the tip of the insertion member has a curved portion that abuts against the elastic member.

7. The medical device according to claim 1, wherein the shaft has an annular abutment surface extending in the radial direction, and the elastic member is disposed axially between the abutment surface and the tip of the insertion member.

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