CN110352080B

CN110352080B - Catheter tip and stent delivery device

Info

Publication number: CN110352080B
Application number: CN201880014726.7A
Authority: CN
Inventors: 西冈亮子
Original assignee: Zeon Corp
Current assignee: Zeon Corp
Priority date: 2017-03-31
Filing date: 2018-03-30
Publication date: 2022-04-05
Anticipated expiration: 2038-03-30
Also published as: JPWO2018181962A1; JP7028240B2; CN110352080A; WO2018181962A1

Abstract

The invention provides a catheter tip (10) having excellent puncture performance, the catheter tip having a first member (100) connected to the distal end of a catheter (2) and a second member (200) fixed so as to axially project from the distal end surface of the first member (100). The material of the second member (200) is harder than the material of the first member (100), and at least one of the first member (100) and the second member (200) is formed with at least one anchoring protrusion (141) for engaging with the other of the first member (100) and the second member (200).

Description

Catheter tip and stent delivery device

Technical Field

The present invention relates to a distal tip provided at a distal end of a catheter and a stent delivery device, and more particularly, to a distal tip for a catheter and a stent delivery device that facilitate insertion of a catheter into a body.

Background

In recent years, in unresectable cases of malignant bile duct stenosis or obstruction, the following report examples are common: in cases where bile duct drainage is required and the approach through the duodenal papilla cannot be performed, a transduodenal (or transgastric transhepatic) bile duct drainage (EUS-BD) under the guidance of an ultrasonic endoscope is performed. EUS-BD refers to the following surgery: when an ultrasonic endoscope is inserted into the duodenum (or stomach), an ultrasonic image is observed in real time, and at the same time, a common bile duct (or intrahepatic bile duct) is punctured from the wall of the duodenum (or stomach) using a puncture needle, and after a guide wire is inserted into the bile duct through the puncture hole, a tubular object serving as a bypass path connecting the inside of the duodenum (or stomach) and the inside of the common bile duct (or intrahepatic bile duct) is inserted and detained along the guide wire. By this operation, drainage of the bile duct can be performed in a form of embedding a tube in the body.

In such a tubular object used as a bypass route in the EUS-BD, a self-expandable stent provided with a coating may be used. As a stent delivery device used in this case, for example, the following devices are known: the stent is expanded in diameter by providing a catheter having an inner sheath slidably inserted through the outer sheath, disposing a stent at a stent disposition portion provided near the distal end of the inner sheath, holding the stent in a reduced diameter state inside near the distal end of the outer sheath, and sliding the outer sheath relative to the inner sheath by pulling the outer sheath on the proximal end side of the catheter.

For example, in the case of bypass connection between the stomach and the intrahepatic bile duct, the puncture is performed from the stomach wall through the abdominal cavity to the intrahepatic bile duct using a puncture needle, a guide wire is passed through the puncture to secure a path, the puncture is expanded using an expander or the like to such an extent that the distal end portion of the catheter can be inserted, then the distal end portion (stent placement portion) of the catheter is passed through the puncture, and in this state, the outer sheath is pulled down to release (expose and expand) the stent, thereby leaving the stent in the puncture.

When a catheter is inserted into the stomach, duodenum, or the like, it is important to prevent the intraluminal space from being damaged. When the distal end portion of the catheter is inserted through a puncture hole in a stomach wall, a duodenal wall, or the like, it is important to smoothly insert the distal end portion. Therefore, patent document 1 proposes a catheter having a distal tip provided with a material having a large elastic modulus at the distal end and a material having a small elastic modulus at the proximal end. Thus, the distal end head has high puncture performance (pushability) and flexibility, and the catheter can be smoothly inserted without damaging the intraluminal lumen. In recent years, however, a demand has arisen for a tip having a piercing property exceeding that of the conventional tip.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2014-195556.

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a catheter tip having excellent puncture performance.

Disclosure of Invention

To achieve the above object, a tip for a catheter according to the present invention includes:

a first member coupled to the distal end of the catheter;

a second member fixed so as to axially project from a distal end surface of the first member,

the material of the second member is harder than the material of the first member,

at least one of the first member and the second member is formed with at least one anchor protrusion for engaging with the other of the first member and the second member.

In the tip for a catheter of the present invention, the second member formed of a material harder than the material of the first member is fixed so as to project axially from the distal end surface of the first member. Therefore, the distal end portion of the catheter tip has high puncture performance (pushability), and the distal end portion of the catheter can be smoothly inserted when the puncture hole is inserted. In another aspect, the distal end of the catheter is coupled to a first member formed of a material that is softer than the material of the second member. Therefore, the proximal surface of the distal tip for a catheter has appropriate flexibility, and when the catheter is inserted into the body lumen, irritation to the body lumen can be reduced.

In the tip for a catheter of the present invention, at least one of the first member and the second member is formed with at least one anchoring protrusion for engaging with the other of the first member and the second member. By adopting such a structure, the first member and the second member are firmly connected, and one of the first member and the second member can be prevented from being detached from the other.

Preferably, the distal end portion of the second member has a curved surface with a narrowed tip. With such a configuration, the contact area between the distal end portion of the second member and the body lumen portion is increased by the curved surface, and the body lumen portion can be pressed with a large pressing force on the curved surface. The puncture property of the tip for a catheter can be further improved.

Preferably, the engagement surface of the distal end of the first member with the second member is a tapered surface with a diameter increasing toward the distal end. With such a configuration, when the catheter tip is manufactured, a portion into which the resin constituting the first member is less likely to flow is less likely to be generated in the mold, and the moldability of the first member can be improved.

The stent delivery device may include a catheter having the catheter tip connected to the distal end thereof.

Drawings

Fig. 1 is a front view showing the overall structure of a stent delivery device having a tip for a catheter according to a first embodiment of the present invention.

Fig. 2A is a sectional view showing the tip for a catheter shown in fig. 1.

Fig. 2B is a sectional view showing a tip for a catheter of a second embodiment of the present invention.

Fig. 2C is a sectional view showing a tip for a catheter according to a third embodiment of the present invention.

Fig. 2D is a sectional view showing a tip for a catheter according to a fourth embodiment of the present invention.

Fig. 2E is a perspective view showing the tip for a catheter shown in fig. 2D.

Fig. 3 is a schematic view showing an operation (puncture) for indwelling a stent in a puncture hole using the stent delivery device shown in fig. 1.

Fig. 4 is a schematic view of an operation (insertion of a guide wire) for indwelling a stent in a puncture hole using the stent delivery device shown in fig. 1.

Fig. 5 is a schematic view showing an operation (starting to insert a catheter) for indwelling a stent in a puncture hole using the stent delivery device shown in fig. 1.

Fig. 6 is a schematic view showing an operation (during insertion of a catheter) for indwelling a stent in a puncture hole using the stent delivery device shown in fig. 1.

Fig. 7 is a schematic view showing an operation (completion of catheterization) for indwelling a stent in a puncture hole using the stent delivery device shown in fig. 1.

Fig. 8 is a schematic view of an operation (halfway releasing the stent) when the stent is placed in the puncture hole using the stent delivery device shown in fig. 1.

Fig. 9 is a schematic view showing an operation (stent release completion) when the stent is left in the puncture hole using the stent delivery device shown in fig. 1.

Fig. 10 is a graph showing the evaluation results of the puncture performance of the catheter tip shown in fig. 1.

Detailed Description

First embodiment

Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. In the present embodiment, a case will be described as an example in which a self-expandable stent having a coating that bypasses and connects the stomach and the intrahepatic bile duct is left in transgastric transhepatic bile duct drainage (EUS-BD) under the guidance of an ultrasonic endoscope. However, the present invention is not limited to the case of bypass-connecting the stomach and the intrahepatic bile duct, and can be widely applied to the case of bypass-connecting the duodenum and the common bile duct, or the hollow organ and another hollow organ. The present invention is not limited to the case of indwelling stents as described above, and can be applied to, for example, biliary duct drainage through the duodenal papilla (the case of indwelling stents in a stricture portion in the common bile duct) and indwelling stents in a stricture portion in a lumen other than the common bile duct.

As shown in fig. 1, the stent delivery device 1 generally has: an elongated catheter 2 inserted into a body (lumen) of a patient through a treatment instrument guide tube of an endoscope (not shown); an operation unit 3 connected to the proximal end side of the catheter 2 for operating the catheter 2 from the outside of the body; a guide wire 4; a stent 5 as an indwelling object; and a catheter tip 10 (hereinafter referred to as "tip 10"). The vicinity of the distal end of the catheter 2 including the stent 5 may be curved according to the shape of the indwelling part, but is drawn as a straight line for convenience.

The catheter 2 is provided with an inner sheath (inner tube) 21 having distal and proximal ends and an outer sheath (outer tube) 22 having distal and proximal ends. Near the distal end of the inner sheath 21 and near the distal end of the outer sheath 22, contrast markers (not shown) are provided, respectively. The contrast marker is a substance that serves as a marker in vivo by detecting its position by X-ray fluoroscopy, and is made of, for example, a metal material such as gold, platinum, or tungsten, or a polymer mixed with barium sulfate or bismuth oxide.

The inner sheath 21 is made of a flexible elongated tube having a lumen through which a guide wire 4 serving as a guide for inserting the catheter 2 into the patient is passed. After the guide wire 4 is inserted into the body to secure a path between the outside and the inside of the body, the distal end side of the catheter 2 can be inserted into a target site in the body by advancing (advancing) the catheter 2 along the guide wire 4. The outer diameter of the inner sheath 21 (a portion where the stent 5 is disposed, which will be described later) is about 0.5 to 3.5 mm.

A fixing ring 25 is integrally fixed to the inner sheath 21 near the distal end thereof, the fixing ring 25 defining the position of the proximal end of the stent 5, and the portion on the distal end side from the fixing ring 25 is a stent arrangement portion. In the stent placement portion, the stent 5 is placed so as to cover the inner sheath 21. Further, another slender tube (not shown) is coaxially provided so as to cover the slender tube constituting the main body of the inner sheath 21 at a portion of the inner sheath 21 closer to the end side than the fixing ring 25, and the portion of the inner sheath 21 closer to the end side than the fixing ring 25 is thicker than the portion of the inner sheath 21 closer to the distal end side than the fixing ring 25. As described above, the inner sheath 21 has a larger portion on the end side than the fixing ring 25, so that the pushing ability of the inner sheath 21 is improved, the operation is improved, and the position of the fixing ring 25 is prevented from shifting to the proximal side.

The outer sheath 22 is made of an elongated tube having flexibility, has an inner diameter slightly larger than the outer diameter of the inner sheath 21, and has the inner sheath 21 inserted through the inner side thereof in such a manner that the inner sheath 21 can slide. The sheath 22 has an inner diameter of about 0.5 to 3.5mm and an outer diameter of about 1.0 to 4.0 mm. By operating the operation portion 3, the outer sheath 22 can slide (move relatively) in the axial direction with respect to the inner sheath 21.

Examples of the material of the inner sheath 21 and the outer sheath 22 include polyolefins such as polyethylene and polypropylene, polyesters such as polyvinyl chloride, polyurethane, ethylene-vinyl acetate copolymer, polyethylene terephthalate and polybutylene terephthalate, various resin materials such as fluorine-based resins such as polyamide, polyether polyamide, polyester polyamide and polyether ether ketone, polyetherimide, polytetrafluoroethylene and fluorinated ethylene-propylene copolymer, and various thermoplastic elastomers such as polystyrene, polyolefin, polyurethane, polyester, polyamide and polybutadiene. Combinations of 2 or more of these materials can also be used.

Although not provided in the present embodiment, an outermost tube (not shown) may be coaxially disposed outside the sheath 22. The outermost tube is made of an elongated tube having flexibility, and has an inner lumen into which the outer sheath 22 is slidably inserted. The outermost tube can be a tube having a size of about 0.05 to 1.0mm larger than the outer diameter of the outer sheath 22. As the material of the outermost tube, polyacetal, polytetrafluoroethylene, fluorinated ethylene-propylene copolymer, polypropylene, or the like can be used.

The stent 5 is a self-expandable stent graft that is expanded from a contracted state by its own elastic force, and has a tubular bare stent formed of a frame and a stent graft section that covers the outer periphery of the bare stent. The bare stent is formed by super-elastic metals or shape memory metals such as nickel-titanium alloy, cobalt-chromium alloy, gold-titanium alloy, beta titanium-based alloy and the like. The surface of the bare stent is covered with a coating film that spreads to fill the space between adjacent frames, and the outer periphery of the bare stent covered with the coating film is covered with a coating portion such as a polymer film.

The total length of the bracket 5 is about 30-200 mm, and is determined according to the distance between the hollow viscera to be connected by bypass; the outer diameter of the tube during diameter expansion is about

Is determined according to the type and size of the hollow organs to be bypassed. The outer diameter of the stent 5 when reduced in diameter is about a fraction of the outer diameter when expanded in diameter. In the present embodiment, the stent 5 is described as one of the constituent members of the stent delivery device 1, but the stent 5 may be replaceable as a member separate from the stent delivery device 1.

As shown in fig. 1, the guide wire 4 is used as a guide for inserting the catheter 2 into the patient, and is inserted into the lumen of the inner sheath 21, and is disposed such that its distal end protrudes from the distal end opening of the distal end head 10 of the inner sheath 21 and its proximal end is exposed to the outside through the proximal end opening 21a of the inner sheath 21 disposed through the operation unit 3. A wire having a diameter of 0.035 inch (≈ 0.889mm), a wire having a diameter of 0.025 inch (≈ 0.635mm), or the like is generally used as the wire, but in the present embodiment, a wire having a diameter of 0.025 inch is used as the wire 4.

The operation portion 3 has a release handle (housing) 31 having a substantially cylindrical shape, and an opening portion on the distal end side of the release handle 31 is closed by integrally attaching a distal end side cover member having a through hole in the central portion thereof, and an opening portion on the proximal end side is closed by integrally attaching a distal end side cover member having a through hole in the central portion thereof.

In the through hole of the distal end side cover member of the release handle 31, the proximal end portion of the sheath 22 is slidably inserted, and the proximal end of the sheath 22 is positioned inside the release handle 31. A groove penetrating inward and outward in the direction of the central axis of the release handle 31 is formed in the side wall thereof. The release lever 32 has a head portion located outside the release handle 31 and a leg portion erected at the center of the head portion, and the leg portion of the release lever 32 is disposed in the groove so as to penetrate therethrough.

The distal end portion (lower end portion) of the leg portion of the release lever 32 is fixed to the proximal end portion of the outer sheath 22 located inside the release handle 31, and the outer sheath 22 can be slid toward the proximal end side or the distal end side with respect to the inner sheath 21 fixed to the release handle 31 (proximal end side cover member) by moving the release lever 32 along the groove.

The proximal end portion of the inner sheath 21 penetrating the outer sheath 22 passes through the inside of the release handle 31, and penetrates through a through hole of a proximal end side cover member of the release handle 31, and the proximal end thereof is positioned outside the release handle 31. The inner sheath 21 is fixed to the proximal end side cover member (release handle 31) at the portion of the through hole. The release handle 31 is provided with an injection port 33, and a syringe is connected to the injection port 33 to inject a physiological saline solution or the like, whereby the physiological saline solution or the like can be injected into the lumen of the outer sheath 22 (outside the inner sheath 21) through the injection port 33 and the lumen of the release handle 31.

In a state where the distal end of the outer sheath 22 reaches the distal tip 10 in a state where the release handle 32 is moved to the distal end of the groove, the stent 5 arranged at the stent arrangement portion of the inner sheath 21 is held in a reduced diameter state inside the distal end of the outer sheath 22. When the release handle 32 is moved to the proximal side of the groove from this state, the outer sheath 22 slides to the proximal side with respect to the inner sheath 21, the stent 5 is relatively pushed out from the distal end of the outer sheath 22, and the stent 5 is released (expanded) by its self-expanding force.

The distal end portion of the inner sheath 21 is attached with the tip 10. When the distal end of the inner sheath 21 (catheter 2) contacts the peripheral wall of the lumen portion in the body, the distal end head 10 reduces the irritation to the lumen portion in the body, reduces the insertion resistance of the catheter 2, and serves to facilitate insertion into the body.

As shown in fig. 2A, the tip 10 has a first member 100 connected to the distal end of the inner sheath 21 and a second member 200 fixed so as to project axially from the distal end surface of the first member 100, and is configured by joining the

members

100, 200.

The ratio L1/L of the axial total length L1 of the first member 100 to the total length L of the tip head 10 is preferably 0.65 to 0.95. The ratio of the axial overall length L2 of the second member 200 to the overall length L of the tip head 10 is preferably 0.2 to 0.4.

A cylindrical hollow portion 160 is formed inside the first member 100 and the second member 200, and the cylindrical hollow portion 160 is a cylindrical space axially penetrating the

members

100, 200. As shown in fig. 2A, the distal end of the inner sheath 21 is inserted into the cylindrical hollow portion 160 to the vicinity of the axial center of the first member 100 while spreading the inner wall of the cylindrical hollow portion 160. The guide wire 4 (not shown) inserted into the lumen of the inner sheath 21 is inserted into the cylindrical hollow portion 160 and protrudes from the distal end opening of the second member 200. The inner diameter of the cylindrical hollow portion 160 is almost equal to the diameter of the guide wire, for example.

The first component 100 has a small diameter portion 110, a proximal taper portion 120, a large diameter portion 130, and a distal taper portion 140. The small diameter portion 110 is a portion on the proximal end side of the distal end 10 and is a cylindrical portion having a small diameter connected to the distal end portion of the inner sheath 21. A curved surface 111 that narrows toward the proximal end is formed at the proximal end of the small diameter portion 110.

The proximal tapered portion 120 is a tapered surface portion that is disposed on the distal side of the small diameter portion 110 and is inclined such that the outer diameter thereof gradually increases from the proximal side (the side on which the small diameter portion 110 is disposed) to the distal side (the side on which the second member 200 is disposed). In the present embodiment, the proximal tapered portion 120 is formed such that the tapered surface is gently inclined.

The large diameter portion 130 is disposed on the distal side of the proximal tapered portion 120, forms the middle portion of the distal tip 10, and is the thickest portion of the distal tip 10 formed in a cylindrical shape having a larger diameter than the small diameter portion 110 and the proximal tapered portion 120. The outer diameter of the large-diameter portion 130 is preferably 1.1 to 1.4 times the outer diameter of the small-diameter portion 110.

The distal tapered portion 140 is a tapered surface portion that is disposed on the distal side of the large diameter portion 130 and is inclined such that the outer diameter thereof gradually decreases from the proximal side to the distal side. In the present embodiment, the tapered surface of the distal tapered portion 140 is constituted by a proximal first tapered surface 143 and a distal second tapered surface 144 according to the inclination angle thereof. The distal end portion of the catheter 2 is smoothly inserted into the body lumen and pushed forward by the outer peripheral surface of the distal tapered surface portion 140 formed by the tapered

surfaces

143, 144. Further, a plurality of tapered surfaces may be further formed on the outer peripheral surface of the distal tapered surface portion 140.

A distal end surface 142, which is a surface perpendicular to the axial direction of the tip head 10, is formed at the distal end of the distal tapered surface portion 140. Distal face 142 is the interface at which the distal end of first component 100 engages second component 200.

An anchor protrusion 141 protruding radially inward is formed on the distal side of the distal tapered portion 140. The anchor convex portion 141 is engageable with the second member 200 (more specifically, an anchor concave portion 221 described later).

An insertion cylindrical portion 170 into which the proximal side (more specifically, a proximal end portion 220 described later) of the second member 200 is inserted is formed in the distal tapered portion 140. As shown in fig. 2A, the insertion cylindrical portion 170 includes: a proximal cylindrical region 171 formed of a cylindrical surface parallel to the axial direction; an intermediate cylindrical region 172 formed of a tapered surface having an outer diameter gradually decreasing from the proximal side to the distal side; a distal cylindrical region 173 formed by a cylindrical surface parallel to the axial direction. The tapered surface of the intermediate cylindrical region 172 is not limited to the tapered surface formed at an oblique angle as shown in the figure, and may have other shapes as long as the outer diameter difference can be formed between the proximal cylindrical region 171 and the distal cylindrical region 173. For example, the tapered surface may be a stepped surface or a stepped surface perpendicular to the axial direction of the tip head 10.

The second member 200 has a protruding portion 210 and a base end portion 220. The projection 210 is a portion axially protruding from the distal end face of the first member 100. The thickness of the distal end portion of the protruding portion 210 is defined to be such a degree that the tip 10 does not bend when pressing the intraluminal cavity, and is preferably 0.1 to 0.3 mm. The ratio L21/L2 of the axial length L21 of the protrusion 210 to the axial overall length L2 of the second member 200 is preferably 0.2 to 0.7. When the catheter 2 is inserted into the intraluminal cavity, the larger the value of L21/L2, the better the puncture property of the distal tip 10 is ensured; from the viewpoint of reducing irritation to the lumen of the body, the smaller the value of L21/L2, the better.

As shown in fig. 2A, the protrusion 210 is formed of a tapered surface inclined such that the outer diameter gradually decreases from the proximal side to the distal side, and the distal end portion thereof has a curved surface 211 narrowing at the tip. The curvature radius of the curved surface 211 is preferably 0.07 to 0.30mm, and more preferably 0.07 to 0.25 mm.

Proximal end 220 is disposed on the proximal side of protrusion 210, and forms a proximal portion of second member 200. The ratio L22/L2 of the axial length L22 of the base end part 220 to the axial overall length L2 of the second member 200 is preferably 0.3 to 0.8.

An anchor recess 221 recessed radially inward is formed on the distal side of the proximal end portion 220. The anchor recess 221 is engageable with the anchor recess 141 of the first member 100. The axial length L23 of the anchor recess 221 is substantially equal to the axial length of the anchor protrusion 141, and the ratio L23/L2 of the axial length L23 of the anchor recess 221 to the axial overall length L2 of the second member 200 is preferably 0.2 to 0.4.

The base end portion 220 is fitted into the fitting cylindrical portion 170, and the fitted portion thereof is joined (connected) by an adhesive or welding. At this time, since the first member 100 and the second member 200 are firmly coupled by the engagement of the anchor convex portion 141 and the anchor concave portion 221, one of the first member 100 and the second member 200 can be prevented from being detached from the other.

In the present embodiment, the second member 200 is formed of a material harder than the first member 100. More specifically, the shore a hardness (JIS K6253) of the material of the first member 100 is preferably 30 to 100, and more preferably 35 to 95. The Shore D hardness (JIS K6253) of the material of the second member 200 is preferably 60 to 80.

Specifically, the first member 100 and the second member 200 are respectively made of a resin such as polyethylene, polyamide, or polyurethane, and among these various resin materials, materials that are different in hardness (shore a hardness) and that allow adhesion or welding between the materials and can be appropriately adhered or welded to each other are selected, wherein the second member 200 is formed of a relatively hard material and the first member 100 is formed of a relatively soft material.

The tip 10 is subjected to a lubricating treatment over the entire outer peripheral surface thereof. This makes the outer peripheral surface of the distal tip 10 including the large diameter portion 130 as a whole easy to slip, and facilitates insertion of the catheter 2. Examples of the lubricating treatment to be applied to the tip end 10 include coating with a fluorine resin, coating with a silicone oil, and coating with a hydrogel.

The molding method for molding such a tip 10 is not particularly limited, and for example, the tip can be manufactured by two-color injection molding from 2 directions, insert injection molding, or the like. Alternatively, the first member 100 and the second member 200 may be separately molded and joined by bonding, welding, or the like.

Next, a stent indwelling operation using the stent delivery device according to the present embodiment will be described with reference to fig. 3 to 9. For example, when a stent is placed in the abdominal cavity so as to bypass and connect the stomach and the intrahepatic duct, as shown in fig. 3, a puncture needle 73 is used to puncture the stomach wall 71 through the abdominal cavity 75 to the bile duct wall 72, thereby forming puncture holes 74 in both the stomach and the intrahepatic duct. After the guide wire 4 is inserted into the lumen of the puncture needle 73, the puncture needle 73 is pulled out from the puncture hole 74, and as shown in fig. 4, the guide wire 4 is inserted into the puncture hole 74, and a path is secured. In fig. 3 to 9, the endoscope is indicated by a two-dot chain line.

After the puncture hole 74 is expanded by an expander (not shown), the release lever 32 of the operation portion 3 is moved to the distal end of the groove, and the distal end portion (the protruding portion 210 of the distal tip 10) of the catheter 2 is inserted into the puncture hole 74 on the stomach wall 71 side in a state where the outer sheath 22 is slid to the distal end side, that is, in a state where the stent 5 arranged at the stent arrangement portion of the inner sheath 21 is held in a reduced diameter state inside the distal end portion of the outer sheath 22 as shown in fig. 5. Since the outer diameter of the protruding portion 210 of the tip 10 is sufficiently small and hard, the tip 10 has high piercing ability and can be easily inserted into the piercing hole 74 on the stomach wall 71 side.

Thereafter, as shown in fig. 6, when the catheter 2 (the inner sheath 21 and the outer sheath 22) is inserted so that the tip 10 is inserted deeper into the abdominal cavity 75 through the puncture hole 74 on the stomach wall 71 side, the puncture hole 74 on the stomach wall 71 side is gradually expanded by the distal taper portion 140 of the tip 10, and the puncture hole 74 on the stomach wall 71 side is expanded by the tip 10 to such an extent that the distal end portion of the catheter 2 can be inserted. Thereafter, the catheter 2 is further advanced, and the distal end portion (the protruding portion 210 of the tip 10) of the catheter 2 is inserted into the puncture 74 on the biliary duct wall 72 side. Since the outer diameter of the protruding portion 210 of the tip 10 is sufficiently small and hard, the tip 10 has high puncture performance, and can be easily inserted into the puncture 74 on the bile duct wall 72 side, as in the case of inserting into the puncture 74 on the stomach wall 71 side.

When the catheter 2 is further advanced, the puncture 74 on the bile duct wall 72 side is gradually expanded by the distal tapered portion 140 of the tip head 10, and the puncture 74 on the bile duct wall 72 side is expanded by the tip head 10 to such an extent that the distal end portion of the catheter 2 can be inserted. The catheter 2 is further advanced, and as shown in fig. 7, the insertion of the catheter 2 is stopped in a state where the distal end of the stent 5 is located inside the bile duct wall 72 and the proximal end of the stent 5 is located inside the stomach wall 71.

Thereafter, the release lever 32 is moved to the proximal end side of the groove in the operation portion 3, and the outer sheath 22 is slid to the proximal end side with respect to the inner sheath 21 as shown in fig. 8. As the sheath 22 slides to the proximal side, the stent 5 is gradually exposed and expanded in diameter from the distal end side of the sheath 22, and by moving the release lever 32 to the proximal end of the groove, as shown in fig. 9, the stent 5 becomes entirely exposed and expanded in diameter. Thereafter, the catheter 2 and the distal end 10 are passed through the inside of the expanded stent 5 and pulled out, thereby completing the indwelling of the stent 5.

In the catheter tip 10 of the present embodiment, the second member 200 formed of a material harder than the material of the first member 100 is fixed so as to project axially from the distal end surface of the first member 100. Therefore, the distal end portion of the catheter tip 10 has high puncture performance (pushability), and can be smoothly inserted when the distal end portion of the catheter 2 is inserted through the puncture 74. On the other hand, the distal end of the catheter 2 is connected to the first member 100 formed of a material softer than the material of the second member 200. Therefore, the proximal surface of the distal tip 10 for a catheter has appropriate flexibility, and when the catheter 2 is inserted into the body lumen, irritation to the body lumen can be reduced.

In the catheter tip according to the present embodiment, an anchor projection 141 for engaging with the second member 200 is formed on the first member 100. Therefore, the first member 100 and the second member 200 are firmly coupled, and one of the first member 100 and the second member 200 can be prevented from being detached from the other.

In addition, the distal end of the second member 200 has a curved surface 211 that narrows at its tip. Therefore, the contact area between the distal end portion of the second member 200 and the body lumen portion can be increased by the amount corresponding to the curved surface, and the body lumen portion can be pressed with a large pressing force on the curved surface. The puncture property of the tip for catheter 10 can be further improved.

Second embodiment

The distal end head 10A of the present embodiment shown in fig. 2B has the same configuration and operational advantages as those of the first embodiment except for the points shown below, and the common parts are not described and are denoted by common reference numerals. As shown in fig. 2B, the tip head 10A has a first member 100A and a second member 200A.

The first component 100A is identical to the first component 100 of the first embodiment, except that it has a distal taper 140A instead of the distal taper 140. In more detail, the distal cone 140 has an anchoring protrusion 141A. The second tapered surface 144A is formed to have a shorter axial length than the second tapered surface 144 in the first embodiment.

The anchoring protrusion 141A is formed to have a length in the axial direction shorter than that of the anchoring protrusion 141 in the first embodiment. A distal end face 142A formed at the distal end of the anchoring projection 141A is a tapered face that increases in diameter toward the distal end. By adopting the above structure, as shown in fig. 2B, the distal end portion of the distal tapered portion 140A is thicker than the distal end portion of the distal tapered portion 140.

The second member 200A is the same as the second member 200 in the first embodiment except that it has a protrusion 210A instead of the protrusion 210 and a base end 220A instead of the base end 220.

More specifically, as shown in fig. 2B, the protruding portion 210A is formed in a cylindrical shape having a length in the axial direction longer on the near side than the length in the axial direction of the protruding portion 210 and an outer periphery formed by a surface parallel to the axial direction. The curved surface 211A is formed to have a radius of curvature larger than that of the curved surface 211.

The base end portion 220A has an anchor recess 221A. The anchoring recess 221A is formed such that the length in the axial direction thereof is shorter than the length in the axial direction of the anchoring recess 221 by an increment of the length in the axial direction of the projection 210A.

The same effects as those of the first embodiment can be obtained in the present embodiment. In the present embodiment, since the distal end portion of the distal tapered portion 140A is thickened, a portion into which the resin constituting the first member 100 is less likely to flow is less likely to be generated in the mold when the tip 10 is manufactured, and the moldability of the first member 100 can be improved.

Third embodiment

The distal end head 10B of the present embodiment shown in fig. 2C has the same configuration and operational advantages as those of the second embodiment described above except for the points described below, and the common parts are not described and are denoted by common reference numerals in the drawings. As shown in fig. 2C, the tip head 10B has a first member 100B and a second member 200B.

The second member 200B is the same as the second member 200A in the second embodiment except that it has a base end part 220B instead of the base end part 220A. More specifically, the proximal end portion 220B is formed so that the axial length thereof is longer on the near side than the axial length of the proximal end portion 220 in the second embodiment, and an anchoring protrusion 222B is formed on the proximal end portion thereof.

The anchor convex portion 222B is formed in a convex shape protruding outward in the radial direction so as to be engageable with the first member 100B (more specifically, with an anchor concave portion 131B described later). The function of the anchoring protrusion 222B is the same as that of the anchoring protrusion 141A in the second embodiment.

The first member 100B is the same as the first member 100A in the second embodiment except that it has a large diameter portion 130B instead of the large diameter portion 130 and a distal tapered portion 140B instead of the distal tapered portion 140. In more detail, the distal taper 140B is formed such that the insertion cylindrical portion 170B also reaches the proximal side of the distal taper 140B.

The large diameter portion 130B has an anchoring recess 131B. The anchor concave portion 131B has a concave shape that is concave outward in the radial direction so as to be engageable with the anchor convex portion 222B of the second member 200. The function of the anchoring recess 131B is the same as that of the anchoring recess 221A in the second embodiment.

The same effects as those of the second embodiment can be obtained in the present embodiment. In the present embodiment, the first member 100B is formed with the anchor concave portion 131B in addition to the anchor convex portion 141A, and the second member 200B is formed with the anchor convex portion 222B in addition to the anchor concave portion 221A. Therefore, in addition to the engagement of the anchor convex portions 141A with the anchor concave portions 221A, the anchor concave portions 131B are also engaged with the anchor convex portions 222B, and the first member 100B and the second member 200B are strongly coupled, so that the detachment of one of the first member 100B and the second member 200B from the other can be reliably prevented.

Fourth embodiment

The distal end head 10C of the present embodiment shown in fig. 2D has the same configuration and operational advantages as those of the first embodiment described above except for the points described below, and the description of common parts will be omitted, and common parts will be denoted by common reference numerals in the drawings. As shown in fig. 2D, the tip head 10C has a first member 100C and a second member 200C.

The second member 200C is the same as the second member 200 in the first embodiment except that the protruding portion 210C is provided instead of the protruding portion 210, and the base end portion 220C is provided instead of the base end portion 220.

The protruding portion 210C is formed so that the length in the axial direction thereof is distally longer than the length in the axial direction of the protruding portion 210 in the first embodiment. A central tapered surface 212C is formed on the outer peripheral surface of the protruding portion 210C on the near side. The central tapered surface 212C is a tapered surface that is inclined such that the outer diameter gradually decreases from the proximal side to the distal side. The angle of inclination of the central taper 212C is approximately equal to the angle of inclination of the distal taper 140C of the first component 100C. The portion of the protruding portion 210C where the central tapered surface 212C is formed has an axial length substantially equal to an axial length of the portion of the protruding portion 210C where the central tapered surface 212C is not formed.

By providing the center tapered surface 212C in the second member 200C, the outer peripheral surface of the second member 200C can be smoothly connected to the outer peripheral surface of the first member 100C at a relatively gentle inclination angle. As a result, the distal end portion (the protruding portion 210C) of the catheter is smoothly inserted into the body lumen and advanced by the action of the central tapered surface 212C. Further, a plurality of tapered surfaces may be formed on the outer peripheral surface of the protruding portion 210C on the near side, in addition to the central tapered surface 212C.

The proximal end portion 220C has an anchor concave portion 221C and an anchor convex portion 222C. The anchor protrusions 221C have a concave shape recessed radially inward so as to be engageable with the first member 100C (more specifically, with an anchor protrusion 141C described later). The anchor recess 221C is formed such that a recess wall surface is vertical, unlike the anchor recess 221A shown in fig. 2C, for example.

The anchor convex portion 222C has a convex shape protruding outward in the radial direction so as to be engageable with the first member 100C (more specifically, with an anchor convex portion 145C described later). The anchor protrusions 222C are formed such that the protrusion wall surfaces are perpendicular, unlike the anchor protrusions 222B shown in fig. 2C, for example.

The first component 100C is identical to the first component 100 of the first embodiment, except for having a proximal taper 120C and a distal taper 140C. The distal taper 140C has a first taper 143C without a structure comparable to the second taper 144 shown in fig. 2A.

The first tapered surface 143C is formed to have a length in the axial direction that is distally longer than the length in the axial direction of the first tapered surface 143 in the first embodiment shown in fig. 2A. In more detail, the first tapered surface 143 shown in fig. 2A extends distally to its boundary with the second tapered surface 144, but the first tapered surface 143C shown in fig. 2D extends distally to its boundary with the central tapered surface 212C of the second component 200C.

An anchor protrusion 141C and an anchor recess 145C are formed in the distal taper portion 140C. The anchor convex portion 141C has a shape protruding radially outward so as to be engageable with the anchor concave portion 221C of the second member 200. The anchor protrusions 141C are formed such that the protrusion wall surfaces are perpendicular, unlike the anchor protrusions 141A shown in fig. 2C, for example.

The anchor concave portion 145C has a concave shape that is concave outward in the radial direction so as to be engageable with the anchor convex portion 222C of the second member 200C. The anchor recess 145C is formed such that a recess wall surface is vertical, unlike the anchor recess 131B shown in fig. 2C, for example.

As shown in fig. 2E, a cutout portion 121C is formed at the proximal end of the proximal taper portion 120C. The cutout portion 121C is formed by cutting out a part of the outer peripheral surface of the proximal tapered portion 120C from the proximal side to the distal side. In the illustrated example, only one notch 121C is formed, but a plurality of notches may be formed. By forming the notch 121C in the proximal tapered portion 120C, when the distal end 10C is used as the distal end of the stent delivery device 1 shown in fig. 1, saline or the like can be injected (infused) into the lumen of the sheath 22 from the injection port 33 while keeping the state in which the distal end of the sheath 22 abuts against the distal end 10C (the state in which the stent 5 having a reduced diameter is held in the sheath 22) unchanged.

The same effects as those of the first embodiment can be obtained in the present embodiment. In the present embodiment, since the anchor convex portions 141C are engaged with the anchor concave portions 221C and the anchor convex portions 222C are engaged with the anchor concave portions 145C, the first member 100C and the second member 200C are firmly coupled to each other, and it is possible to reliably prevent one of the first member 100C and the second member 200C from being detached from the other.

The present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention.

For example, the shape of the distal end of the projection 210 of the tip 10 is not limited to the example shown in fig. 2A; for example, the distal end may be formed in a zigzag shape by providing projections and recesses, or in a fork shape by providing a slit extending toward the proximal side.

The inclination angles of the first tapered surface 143 and the second tapered surface 144 formed on the outer periphery of the distal tapered portion 140 may be changed as appropriate. In addition, the inclination angle of the tapered surface formed on the outer periphery of the proximal tapered portion 120 may be changed as appropriate.

In the example shown in fig. 2A and the like, the second taper surface 144 of the distal taper portion 140 is continuously (smoothly) connected to the outer peripheral surface of the protrusion portion 210, but may be intermittently connected. A stepped surface or a stepped surface perpendicular to the axial direction of the distal end 10 may be formed on the boundary between the outer peripheral surface of the distal tapered portion 140 and the outer peripheral surface of the protrusion 210.

In the above embodiment, 3 or more sets of the anchoring convex portions and anchoring concave portions may be formed. In this case, the first member 100 and the second member 200 are more firmly coupled, and one of the first member 100 and the second member 200 can be effectively prevented from being detached from the other.

[ examples ]

The present invention will be described in further detail below with reference to specific examples, but the present invention is not limited to these examples.

Examples

In the tip 10, the first member 100 (full length L1 ═ 10mm) was molded from a polyurethane resin (trade name: Tecoflex EG93A-B40, manufactured by Lubrizol) having a shore a hardness (JIS K6253) of 95, and the second member 200 (full length L2 ═ 3.4mm) was molded from a polyurethane resin (trade name: Tecoflex EG 72-B40, manufactured by Lubrizol) having a shore D hardness (JIS K6253) of 67, and the first member 100 and the second member 200 were welded to each other to produce a sample of the tip 10 having a full length (L) of 11mm and a length (L21) of the projecting portion 210 in the axial direction of 1 mm.

Comparative example

The same samples as in the example were prepared except that the entire length (L2) of the second member 200 was set to 2.4mm, and the protrusion 210 was fixed to the inner side of the first member 100 so as not to protrude from the distal end of the first member 100 in the axial direction (L21 is 0 mm).

Evaluation of

The load test was performed on each sample composed of the produced inner sheath 21 and the tip 10.

The load test was carried out in the following manner. That is, each sample is lowered in the vertical direction, and the tip end surface (bent portion 211) of the protruding portion 210 of each sample is pressed against the polyvinyl chloride sheet. During this period, the load applied to the protrusion 210 of each sample was measured by a load cell, and the relationship between the lowering distance and the load was determined. The solid line represents examples, the broken line represents comparative examples, and the results of the load test are shown in fig. 10.

In the evaluation of the load test, the maximum load was about 0.90N with respect to the sample of the example, and the maximum load was about 1.4N with respect to the sample of the comparative example. Namely, it was confirmed that the sample of the example had significantly improved puncture properties as compared with the sample of the comparative example.

Description of the reference numerals

1: support transfer device

2: catheter tube

21: inner sheath

21 a: opening of the container

22: sheath

25: fixing ring

3: operation part

31: release handle

32: release lever

33: injection port

4: guide wire

5: support frame

10. 10A, 10B, 10C: top end head

100. 100A, 100B, 100C: first part

110: small diameter part

111: bending part

120. 120C: proximal taper

121C: cut-out part

130. 130B: large diameter part

140. 140A, 140B, 140C: distal taper

141. 141A, 1141C, 222B, 222C: anchoring protrusion

142. 142A: distal end face

143. 143C: first conical surface

144. 144A: second conical surface

160: tubular hollow part

170. 170B: inserting tubular part

171: proximal barrel region

172: intermediate cylindrical region

173: distal barrel region

200. 200A, 200B, 200C: second part

210. 210A, 210C: projection part

211. 211A: curved surface

212C: central conical surface

220. 220A, 220B, 220C: basal end part

145C, 221A, 131B, 221C: anchoring recess

71: stomach wall

72: wall of liner

73: puncture needle

74: puncture hole

75: the abdominal cavity.

Claims

1. A tip for a catheter, comprising:

a first member coupled to the distal end of the catheter; and

a second member fixed in such a manner as to project axially from a distal end face of the first member,

the material of the second part is harder than the material of the first part,

at least one of the first member and the second member is formed with at least one anchoring protrusion for engaging with the other of the first member and the second member,

the second member has a proximal end portion to which the first member is fixed, and a protruding portion located on a distal side of the proximal end portion and protruding in an axial direction from a distal end surface of the first member,

a central tapered surface inclined such that the outer diameter thereof gradually decreases from the proximal side to the distal side is formed on the outer peripheral surface of the protruding portion on the proximal side,

a cylindrical surface located farther from the center tapered surface and having a constant outer diameter from the near side to the far side is formed on the outer peripheral surface of the far side of the protruding portion,

a distal taper portion that is inclined so that the outer diameter thereof gradually decreases from the proximal side to the distal side is formed on the outer peripheral surface of the distal side of the first member,

the central taper angle is approximately equal to the distal taper angle,

the central tapered surface is located between the outer peripheral surface of the base end portion and the cylindrical surface.

2. The tip for a catheter as set forth in claim 1,

the distal end of the second member has a curved surface that narrows at its tip.

3. The tip for catheter according to claim 1 or 2,

the engagement surface of the distal end of the first member with the second member is a tapered surface that increases in diameter toward the distal end.

4. A stent delivery device is characterized in that,

having a catheter with a distal end to which the tip for a catheter of claim 1 or 2 is attached.