JP7102846B2 - Stent delivery device - Google Patents

Description

The present invention relates to a stent delivery device used to place a stent in a lumen.

A medical method is known in which a stent is placed in a stenosis or an obstruction (hereinafter, these are simply referred to as a stenosis) in order to secure the patency of a lumen in the body such as a digestive tract or a blood vessel. As a device for indwelling a self-expanding stent in a lumen, for example, the stent delivery device described in Patent Document 1 is known.

This stent delivery device has an inner sheath and an outer sheath into which the inner sheath is slidably inserted, and a stent is placed in a stent placement portion provided near the distal end of the inner sheath to arrange the outer sheath. The stent is held in an elastically reduced diameter inside near the distal end of the stent. Then, by operating the operation unit provided on the proximal end side and sliding it toward the proximal end side so as to pull back the outer sheath with respect to the inner sheath, the stent is released from the outer sheath and the stent self. The stent is expanded and released by the expanding force.

By the way, the stent needs to be accurately placed at the target position (stenosis) in the lumen. However, for example, when a stent delivery catheter is inserted into the large intestine via a lower gastrointestinal endoscope and the stent is placed in the narrowed part of the large intestine, the stent is placed at a position higher than the target position where the operator plans to place the stent. It has been reported that the stent may be placed on the back side (small intestine side) with a misalignment.

Such an event occurs when the stent is released, for example, when the stent is placed in the narrowed part of the transverse colon of the large intestine, because the transverse colon is not fixed to the peritoneum unlike the ascending colon, the descending colon, and the rectum. , The intestinal tract is released in a state of being pulled toward the front side (anal side) due to the friction between the outer sheath and the inner wall of the intestinal tract, and as a result, it is placed on the back side (small intestine side) from the target position. It is a cause.

Japanese Unexamined Patent Publication No. 2012-139471

The present invention has been made in view of these points, and an object of the present invention is to provide a stent delivery device capable of accurately placing a stent at a target position.

In order to achieve the above object, the stent delivery device according to the present invention is
A stent delivery device that places a stent in the lumen.
A stent placement portion for placing the stent on the outer peripheral surface near the distal end, and an opening on the side portion on the distal end side of the stent placement portion to supply and drain fluid from the proximal end side. An inner sheath with a supply / discharge path and
An outer sheath in which the inner sheath is slidably inserted and the stent placed in the stent placement portion is held in a reduced diameter state.
A stent delivery device having a balloon provided so as to surround an opening on the distal end side of the supply / drainage path of the inner sheath and expanding or contracting when fluid is supplied / discharged through the supply / drainage path. be.

When placing a stent in a lumen using the stent delivery device according to the present invention, first, the stent held in the outer sheath is placed at a target position (target position) in the lumen. Adjust the position. By inflating the balloon in this state, the inner sheath is fixed in the lumen by utilizing the frictional force between the balloon and the lumen wall. The outer sheath is then slid toward the proximal end to release the stent. Even if the lumen wall is pulled toward you due to friction between the outer sheath and the inner surface of the lumen wall when releasing the stent, the inner sheath is fixed in the lumen at the balloon part. , The relative position change between the lumen and the stent is small, and as a result, the stent can be placed accurately at the target position.

FIG. 1A is a front view showing the overall configuration of the stent delivery device according to the embodiment of the present invention. FIG. 1B is a cross-sectional view taken along the line Ib-Ib of FIG. 1A. FIG. 1C is an enlarged side view showing a portion near the distal end of the stent delivery device of FIG. 1A. FIG. 1D is a diagram showing a state in which the outer sheath of FIG. 1C is slid toward the proximal end side to expose the stent arrangement portion. FIG. 2A is a side view showing an example of a stent that can be used in the stent delivery device of FIG. 1A. FIG. 2B is an enlarged view showing the end of the stent of FIG. 2A. FIG. 2C is a partially enlarged view showing the IIc portion of FIG. 2B in an enlarged manner. FIG. 3A is a diagram showing a cylindrical body used for manufacturing the stent of FIG. 2A. FIG. 3B is a diagram showing a straight tubular mesh-like cylinder formed by laser-cutting the cylinder of FIG. 3A. FIG. 3C is a diagram showing a state in which a mandrel is inserted into the lumen of the mesh-like cylinder of FIG. 3B. FIG. 4 is a side view showing another example of a stent that can be used in the stent delivery device of FIG. 1A. FIG. 5A is a cross-sectional view showing the configuration of the operation unit of the stent delivery device of FIG. 1A, and is a diagram showing a state in which the push button is not pressed. FIG. 5B is a diagram showing a state in which the push button of FIG. 5A is pressed and pushed.

Hereinafter, embodiments of the stent delivery device according to the present invention will be described with reference to the drawings. In the stent delivery device of the present embodiment, in order to secure the patency of the narrowed portion of the large intestine that has been narrowed due to the formation of a tumor or the like, a self-expanding stent is placed in the narrowed portion using an endoscope. It is a stent delivery device for the large intestine used for the purpose.

The stent delivery device according to the present invention can be particularly preferably used as a stent delivery device for the large intestine for placing a stent in the large intestine, where it is particularly difficult to place the stent accurately at a target position. However, the stent delivery device according to the present invention provides stent delivery for ensuring the patency of not only the large intestine but also other gastrointestinal tracts such as the small intestine, duodenum, and bile duct, as well as ureters, blood vessels, and other cavities. It can be used as a device.

First, refer to FIG. 1A. The stent delivery device 1 is connected to the elongated catheter portion 2 inserted into the patient's body (lumen) and the proximal end side of the catheter portion 2 via a treatment tool guide tube of an endoscope (not shown), and is connected to the body. It is configured to roughly include an operating portion (handle) 3 for operating the catheter portion 2 in the body from the outside, and a self-expandable stent 5 as an indwelling target.

The catheter portion 2 includes an inner sheath 21 having a distal end and a proximal end, and an outer sheath 22 having a distal end and a proximal end. In FIG. 1A, in order to illustrate the internal components of the outer sheath 22, a part of the outer sheath 22 is excluded, but in reality, the outer sheath 22 is from the distal end to the proximal end. It is a tubular body with no defects.

The inner sheath 21 is made of a flexible elongated tube, and has a guide wire lumen 21a and a balloon lumen (supply / discharge path) 21b that do not communicate with each other inside the inner sheath 21 (see FIG. 1B). The outer diameter of the inner sheath 21 is about 0.5 to 4.0 mm.

The guide wire lumen 21a is a lumen through which a guide wire 4 used as a guide for inserting the catheter portion 2 into the patient's body is inserted. After inserting the guide wire 4 into the body to secure a path between the outside and the inside of the body, the catheter portion 2 is pushed (advanced) along the guide wire 4 to make the distal end side of the catheter portion 2 the purpose of the body. Can be inserted into the site. The guide wire lumen 21a is also used as a flow path for a contrast medium when performing X-ray imaging in the body, or as a flow path for supplying physiological saline or the like, if necessary.

The balloon lumen 21b is a lumen for circulating a fluid (air in this embodiment) for expanding or contracting the balloon 27 described later, and the distal end side thereof extends to the distal end of the inner sheath 21. It is open to the side near the distal end of the inner sheath 21. The opening 21c on the distal end side of the balloon lumen 21b is provided on the distal end side of the stent placement portion 26 described later (see FIG. 1D).

A tip 24 formed in a tapered shape is attached to the distal end of the inner sheath 21. The tip 24 has a lumen and an opening 24a that communicate with the distal end of the guidewire lumen 21a of the inner sheath 21. The tip tip 24 plays a role of reducing the insertion resistance of the catheter portion 2 and facilitating insertion into the body, and is made of polyamide, polyamide elastomer, polyurethane, fluororesin such as polytetrafluoroethylene, polyethylene and the like. It can be formed from a polyolefin resin or the like.

A fixing ring 25 is integrally fixed in the vicinity of the distal end of the inner sheath 21, and the fixing ring 25 is for defining the position of the proximal end of the stent 5, and the fixing ring 25 is used from the fixing ring 25. A predetermined portion on the distal end side is a stent placement portion 26 (see FIG. 1D). The stent 5 is arranged in the stent arrangement portion 26 so as to cover the inner sheath 21.

A contrast marker (contrast marker for detecting the orientation around the axis) 25a for detecting the posture around the central axis of the inner sheath 21 is provided on a part of the fixing ring 25 of the inner sheath 21 in the circumferential direction. In the present embodiment, the contrast marker 25a for detecting the axial orientation is provided on the fixing ring 25, but is provided not on the fixing ring 25 but on a part of the stent arrangement portion 26 of the inner sheath 21 or a portion in the vicinity thereof in the circumferential direction. You may.

The contrast marker for detecting the axial posture may be provided on the stent 5 as described in detail later, and in that case, the contrast marker 25a for detecting the axial posture of the inner sheath 21 may be omitted. Further, although not shown, a contrast marker (a contrast marker for detecting an axial position) for detecting a position in a direction along the central axis may be provided in the vicinity of the distal end of the inner sheath 21.

These contrast markers for axial orientation detection 25a and contrast markers for axial position detection are detected as images by X-ray imaging and serve as markers in the body, and are, for example, gold, platinum, platinum iridium alloy, platinum, and the like. Silver, stainless steel and the like can be used. These contrast markers 25a may be composed of a resin molded product containing a powder of an X-ray contrast material. As the powder of the X-ray contrasting material used for these contrast markers 25a, barium sulfate powder, bismuth subcarbonate powder, tungsten powder, the above-mentioned metal powder and the like can be used.

A balloon 27 is provided in the vicinity of the distal end side of the inner sheath 21 and between the stent placement portion 26 and the tip tip 24 so as to surround and cover the opening 21c on the distal end side of the balloon lumen 21b. ing.

The balloon 27 expands when a fluid (air in the present embodiment) is supplied (injected) into the balloon 27, and conversely contracts when it is discharged (sucked). The balloon 27 is a rotating body-shaped balloon whose rotation axis is the axis of the inner sheath 21. The inner sheath 21 can be releasably fixed in the large intestine by the frictional force generated by the inflated balloon 27 pressing against the inner wall of the large intestine.

As the material for forming the balloon 27, an elastic material is preferable, and among them, a material having a 100% modulus (value measured according to JIS K 6251) of 0.1 to 10 MPa is preferable, and 1 to 5 MPa is preferable. Is particularly preferable. If the 100% modulus is too small, the strength of the balloon 27 may be insufficient, and if it is too large, the balloon 27 may not be able to be inflated to a sufficient size. Further, specific examples of the stretchable material suitable for forming the balloon 27 include natural rubber, silicone rubber, polyurethane elastomer and the like.

In the present embodiment, the balloon 27 is tubular as a whole in a contracted state, and substantially cylindrical joint portions 27a and 27b to be joined to the outer peripheral surface of the inner sheath 21 are formed at both ends thereof. An expansion portion 27c that expands by supplying a fluid to the inside is formed between the joint portions 27a and 27b. The inflated portion 27c of the balloon 27 holds the axis of the inner sheath 21 in a state where no external force is received (a state in which no fluid is supplied inside and the internal pressure balances with the external pressure and the balloon 27 contracts). It is formed in the shape of a rotating body formed by rotating a convex curve toward the outside of the inner sheath 21 as a rotation axis. By using such a balloon 27, the fixation of the inner sheath 21 to the large intestine by the inflated balloon 27 can be further strengthened. The method of joining the joining portions 27a and 27b of the balloon 27 and the inner sheath 21 is not particularly limited, and for example, bonding with an adhesive, heat welding, welding with a solvent, ultrasonic fusion, high frequency welding, etc. Can be mentioned.

The maximum outer diameter of the inflated portion 27c of the balloon 27 in a state where it is not subjected to an external force is preferably 110 to 200% of the outer diameter of the joint portion 27b. If this ratio is too small, the effect of improving the strength of fixation to the large intestine may not be sufficiently obtained, and if it is too large, the balloon 27 may be in a contracted state when the balloon catheter 1 is inserted into the body. May get in the way.

Further, the outer diameter of the balloon 27 (expanding portion 27c) at the time of expansion may fluctuate depending on the pressure of the fluid supplied to the inside, but since it is pressed against the inner wall of the large intestine to fix the inner sheath 21 in the large intestine, it is 10 to 100 mm. It is preferable that the setting is within the range of. The length of the inflated portion 27c of the balloon 27 (the length along the axial direction of the inner sheath 21) is preferably 10 to 50 mm, and the wall thickness is preferably 0.10 to 0.50 mm. The wall thickness of the balloon 27 is preferably uniform along the circumferential direction.

The method for producing the balloon 27 using the stretchable material is not particularly limited, and a known method may be used as a film forming method for the stretchable material, but it is preferable to use a dipping molding method. In the dipping molding method, a stretchable material and various additives are dissolved in a solvent to form a solution or suspension, and a mold having an outer shape substantially equal to the desired balloon shape is formed in this solution (suspension). Immerse and apply a solution (suspension) to the surface of the mold and evaporate the solvent to form a film on the surface of the mold. By repeating this dipping and drying, a balloon having a desired wall thickness can be formed. Depending on the type of elastic material, if necessary, cross-linking is performed after film formation.

The outer sheath 22 is made of a flexible elongated tube, has an inner diameter slightly larger than the outer diameter of the inner sheath 21, and the inner sheath 21 is slidably inserted inside the outer sheath 21. The inner diameter of the outer sheath 22 is about 0.5 to 4.5 mm, and the outer diameter is about 1.0 to 5.0 mm. The outer sheath 22 can slide (relatively move) in the axial direction with respect to the inner sheath 21 by operating the operation unit 3. Although not shown, a contrast marker (a contrast marker for detecting an axial position) for detecting a position in a direction along the central axis may be provided in the vicinity of the distal end of the outer sheath 22.

Examples of the material of the inner sheath 21 and the outer sheath 22 include polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyurethane, ethylene-vinyl acetate copolymers, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides, and polyether polyamides. , Polyester polyamide, polyether ether ketone, polyetherimide, polytetrafluoroethylene and various resin materials such as fluororesin such as tetrafluoroethylene / hexafluoropropylene copolymer, polystyrene-based, polyolefin-based, polyurethane-based, polyester Various thermoplastic elastomers such as based, polyamide-based, and polybutadiene-based can be used. Two or more of these can be used in combination.

In some cases, an outer sheath tube made of a flexible elongated tube into which the outer sheath 22 is slidably inserted is provided, but in the present embodiment, the outer sheath tube is not provided.

The guide wire 4 is inserted into the guide wire lumen 21a (see FIG. 1B) of the inner sheath 21 when the stent delivery device 1 is inserted into the body, and the distal end thereof is the distal end of the tip 24 of the tip 24 of the inner sheath 21. Along with protruding from the opening 24a (see FIG. 1C), the proximal end thereof is outward via a branch pipe 6b and a port 6c connected to the proximal end of the inner sheath 21 arranged through the operating portion 3. Arranged to be exposed.

As shown in FIGS. 2A to 2C, the stent 5 has a substantially cylindrical outer shape curved in the axial direction, for the purpose of ensuring the patency of the stenosis generated in the curved portion of the large intestine. used. In the present embodiment, the stent 5 is not a so-called covered stent in which the outer peripheral surface side thereof is coated with a resin film or the like, but a bare stent not coated with a film or the like. However, the stent 5 can also be used as a covered stent by covering it with a resin film or the like. In addition, in FIG. 2A and FIG. 4 which will be referred to later, in order to avoid crossing, only the front surface side of the stent 5 is displayed except for the annular units 51a arranged at both ends of the stent 5, and the back surface side is omitted. The back surface side of the annular unit 51a at both ends is indicated by a dotted line in order to distinguish it from the front surface side.

The stent 5 has a tubular portion 51 that exhibits a tubular shape. The tubular portion 51 has a plurality of ring-shaped (endless annular) annular units 51a, and has a structure in which a plurality of annular units 51a are connected along a central axis AX set to a predetermined curved shape. There is. Each annular unit 51a is connected to an adjacent annular unit 51a via a connecting portion 51b (see FIGS. 2B and 2C).

Each annular unit 51a is composed of a wire rod extending in the circumferential direction while repeatedly bending. The annular unit 51a has a first bent portion 51d that is convex on one side in the axial direction and a second bent portion 51e that is convex on the other side in the axial direction, and the first bent portion 51d and the second bent portion 51d. The bent portions 51e have a zigzag shape that is alternately repeated in the circumferential direction.

The connecting portion 51b connects one first bent portion 51d of the annular unit 51a adjacent to each other and the other second bent portion 51e. As shown in FIG. 2B, which is a developed view of the stent 5, each annular unit 51a has 20 first bending portions 51d and 20 second bending portions 51e, and the adjacent annular units 51a are in the circumferential direction. It is connected by five connecting portions 51b arranged at equal intervals. The connecting portion 51b has a substantially inverted S-shaped curved shape (see FIG. 2C), and the annular units 51a are flexibly connected so that the adjacent annular units 51a can be relatively moved to each other. However, the number of the first bent portion 51d and the second bent portion 51e included in the annular unit 51a, and the number, arrangement, and shape of the connecting portions 51b are not particularly limited.

The bent portions 51d or 51e on the open end side of the annular unit 51a arranged at both ends of the stent 5 are provided with a plurality of eyelets formed in a substantially annular shape in place of the connecting portion 51b. Contrast-enhanced markers 51c formed in a substantially disk shape are fitted and joined to the eyelets of the above. These contrast markers 51c are for detecting the axial position of the stent 5 in the lumen by X-ray imaging or the like. The presence / absence and shape of the contrast marker 51c in the stent 5 and the position where the contrast marker 51c is provided are not particularly limited. As the X-ray contrast material used for the contrast marker 51c, the same material as the contrast marker 25a described above can be used.

In the present embodiment, since these contrast markers 51c are uniformly arranged in the circumferential direction of the annular unit 51a arranged at both ends of the stent 5, the posture around the axis of the stent 5 is changed. It is difficult to detect. Therefore, the shape and configuration of these contrast markers 51c may be different from each other, or the arrangement may be devised so that the posture around the axis of the stent 5 can be detected.

The wire diameter of the wire rod constituting the annular unit 51a of the stent 5 is preferably about 0.05 to 1 mm. When the cross section of the wire rod is a strip-shaped body having a rectangular cross section, for example, the length in the long side direction is 0.1 to 1 mm and the length in the short side direction is about 0.05 to 0.5 mm. Is preferable.

Since the stent 5 of the present embodiment is a large intestine stent that is placed in the large intestine where peristaltic movement is active, its dimensions are preferably 10 to 40 mm in outer diameter and 20 to 200 mm in length. However, the external dimensions of the stent 5 may be optimal depending on the size of the internal lumen in which the stent 5 is placed. For example, the outer diameter is set in the range of 2 to 40 mm and the length is set in the range of 5 to 200 mm. be able to.

The outer diameter of the stent 5 is contracted in the radial direction to about a fraction of the above value by elastically deforming the stent 5 when the stent 5 is transported to the indwelling site by the stent delivery device 1. It is housed in the stent delivery device 1. 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 can be replaced as a separate member from the stent delivery device 1.

The material of the stent 5 is selected so that the stent 5 can return from the contracted state due to elastic deformation to the original state by the self-expanding force. Specific examples thereof include nickel titanium (Ni—Ti) alloy and stainless steel. Examples include metals such as steel, tantalum, titanium, cobalt-chromium alloys, and magnesium alloys. In this embodiment, the stent 5 is made of a Ni—Ti alloy, which is a superelastic alloy.

The stent 5 of this embodiment can be manufactured as follows. First, as shown in FIG. 3A, a cylinder (pipe) 52 made of a material for forming the stent 5 is prepared. Then, for example, by performing laser processing (laser cutting) using a YAG laser or the like, as shown in FIG. 3B, a straight tubular mesh tube having a predetermined pattern (see FIGS. 2B and 2C). The body 53 is molded. Then, as shown in FIG. 3C, a mandrel 54 having a desired curved shape is inserted into the lumen of the mesh-like tubular body 53 of FIG. 3B to form the mesh-like tubular body 53 into the curved shape of the mandrel 54. It is curved along the line, and in this state, heat treatment is performed for a predetermined time in a predetermined temperature environment to shape (shape memory). After shaping, the mandrel 54 is pulled out and polished by electric field polishing or marking, and as shown in FIG. 2A, the stent has a shape curved in the axial direction in a state where no external force acts. 5 is manufactured.

The stent 5 is arranged in the stent arrangement portion 26 in a substantially linearly deformed state by inserting the stent arrangement portion 26 of the inner sheath 21 into the lumen thereof, and the outer sheath 22 is placed in a reduced diameter state. It is housed in the outer sheath 22 by sliding it toward the distal end.

When arranging the stent 5 on the stent arranging portion 26 of the inner sheath 21, the posture of the stent 5 is related to the position of the contrast marker 25a for detecting the axial posture. Specifically, for example, the posture around the axis of the stent 5 is adjusted so that the dorsal side (which may be the ventral side) of the stent 5 and the contrast marker 25a coincide with each other, and the stent 5 is housed in the outer sheath 22 in this state. As a result, when the stent 5 is placed in the constricted portion generated in the curved portion of the large intestine, the position of the contrast marker 25a around the axis is confirmed so that the posture is curved corresponding to the curvature of the constricted portion. In addition, the posture around the axis of the stent 5 can be adjusted. As described above, if the stent 5 is provided with a contrast marker for detecting the orientation around the axis, it is possible to eliminate the need for posture adjustment work when the stent 5 is attached to the stent arrangement portion 26, which is convenient.

In the present embodiment, the shape of the stent 5 is approximately a quarter arc shape as shown in FIG. 2A, but this is an example and is appropriate depending on the shape of the site where the stent 5 should be placed. It is possible to use a stent having a different shape, and a linear stent can also be used. Further, even when a curved stent is used, for example, it may be a stent 5'with a substantially three-quarter arc shape as shown in FIG. 4, and although not shown, it is approximately a half yen. It may be arcuate or other arcuate. Further, not only the arc shape but also other curved shapes such as a parabola or a combination thereof may be used. A straight portion formed substantially linearly may be arranged at one end or both ends of the stent 5. Further, it may be substantially S-shaped or the like.

Next, the operation unit 3 of the stent delivery device 1 will be described with reference to FIGS. 1A, 1B, 5A and 5B. The operation unit 3 has a handle that is a means for the operator to grip the stent 5 by hand and perform a release operation of the stent 5. The housing 31 constituting the handle has a substantially linear lower side portion 31a so that the index finger, middle finger, ring finger and little finger (or one or more of them) can be arranged when gripped by the operator's hand. It has an upper side portion 31b having a loose inverted arcuate recess so that a portion of the base of the thumb and a portion of the palm near the base of the thumb can be arranged.

The housing 31 has a sheath accommodating portion 32 that defines a substantially columnar space into which the proximal end side of the inner sheath 21 and the outer sheath 22 is drawn. The distal end of the sheath accommodating portion 32 has an opening 32a for pulling in these sheaths 21 and 22, and the proximal end of the sheath accommodating portion 32 is in contact with the proximal end of the outer sheath 22. The sheath 22 is closed by a bottom surface 32b that defines the stroke end when slid. A through hole is formed in the central portion of the bottom surface 32b, and the proximal end of the inner sheath 21 is arranged through the through hole and fixed on the outer peripheral surface thereof by adhesion or the like.

As shown in FIG. 1A, branch pipes 6b and 6d are connected to the proximal end of the inner sheath 21 that penetrates the through hole of the bottom surface 32b of the housing 31 at the portion of the cover 6a. The branch tube 6b is a tube whose distal end is connected to the proximal end of the guide wire lumen 21a (see FIG. 1B) of the inner sheath 21, and the branch tube 6d is a balloon whose distal end is the inner sheath 21. A tube connected to the proximal end of the lumen 21b (see FIG. 1B). The material of the branch pipes 6b and 6d is not particularly limited, but it is preferable to use a polymer material.

A port 6c is connected to the proximal end of the branch pipe 6b, and a port 6e is connected to the proximal end of the branch pipe 6d. The guide wire 4 can be inserted through the opening of the port 6c and inserted into the guide wire lumen 21a of the inner sheath 21. Further, a syringe or the like is connected to the port 6c so that a contrast medium or a chemical solution or the like can be sent to the guide wire lumen 21a of the inner sheath 21. A syringe or the like is connected to the port 6e so that a fluid (air in the present embodiment) for expanding or contracting the balloon 27 can be supplied to or sucked into the balloon lumen 21b.

The material of the ports 6c and 6e is not particularly limited, but it is preferable to use a transparent polymer material. The method of connecting the branch pipe 6b and the guide wire lumen 21a of the inner sheath 21 and the branch pipe 6d and the balloon lumen 21b is not particularly limited, but for example, the distal ends of the branch pipes 6b and 6d are tapered. It may be formed by molding, applying an adhesive to the outer peripheral surface thereof, and inserting the end portion into the corresponding lumens 21a and 21b of the inner sheath 21 to bond the inner sheath 21.

The connection portion between the inner sheath 21 and the branch pipes 6b and 6d is reinforced and protected by the cover 6a. The cover 6a is provided so as to cover the connection portion between the inner sheath 21 and the branch pipes 6b and 6d. The shape of the cover 6a is not particularly limited, but is usually box-shaped or tubular. The material of the cover 6a is not particularly limited, but it is preferable to use a polymer material. It is also possible to use the heat shrink tube as the cover 6a.

At the portion near the distal end of the upper side portion 31b of the housing 31, the push button 33 has a predetermined angle θ1 in the extending direction (the axial direction of the sheath accommodating portion 32) of the portion existing in the housing 31 of the outer sheath 22. It is slidably held in the direction A1 where it intersects with. That is, the housing 31 is provided with a button accommodating portion 34 that defines a substantially cylindrical space, and the axial direction A1 of the button accommodating portion 34 is the axial direction (outer) of the sheath accommodating portion 32. It is formed so as to substantially coincide with the direction in which the sheath 22 extends) at a predetermined angle θ1.

The tip end side of a substantially columnar push button 33 is inserted into the opening side of the button accommodating portion 34, and the push button 33 is slidably held along the axial direction of the button accommodating portion 34. Although not shown, a part of the push button 33 is provided with a mechanism for engaging with a part of the button accommodating portion 34 to prevent the push button 33 from coming out of the button accommodating portion 34. ing. A spring support portion 34a is provided in the intermediate portion of the button accommodating portion 34, and a coil spring 35 is interposed between one surface of the spring support portion 34a and the tip end surface of the push button 33.

When no external force acts on the push button 33 (when it is not pressed so as to be pushed into the button accommodating portion 34), as shown in FIG. 5A, the push button 33 is in a predetermined first position separated from the outer sheath 22 (exit described above). It is urged by the coil spring 35 so as to be located at a position (position defined by the prevention mechanism). Further, when the push button 33 is pressed so as to be pushed into the button accommodating portion 34, as shown in FIG. 5B, the outer sheath is more than the first position against the urging force of the coil spring 35. It is possible to move to a predetermined second position close to 22.

When the pressure on the push button 33 is released, the push button 33 returns to the original first position by the urging force of the coil spring 35. The second position of the push button 33 is defined by the position of the spring support portion 34a and the dimension in the longitudinal direction when the coil spring 35 is compressed.

The push button 33 places the abdomen of the index finger, middle finger, ring finger and little finger (or one or more of them) on the lower side portion 31a by the operator's hand, and the base portion of the thumb and the base portion of the thumb of the palm. It is configured so that it can be pressed or released by the belly of the tip of the thumb (the part beyond the first joint) by bending and stretching the thumb in a state where the vicinity portion of the thumb is arranged on the upper side portion 31b and gripped. There is.

Considering that the push button 33 can be pressed and released by the thumb ergonomically without stress, the position of the end face on the distal end side of the push button 33 (first position) and the amount of pushing (first position and first position). The dimension between the two positions) is set.

The pushing amount (stroke length) of the push button 33 is set to an optimum value in relation to the above-mentioned ergonomic viewpoint and the feeding amount of the coil member 23 (outer sheath 22) by pressing the push button 33 once. To.

Similarly, considering that the push button 33 can be pressed and released by the thumb ergonomically without stress, the axial direction of the button accommodating portion 34 (sliding direction of the push button 33) A1 accommodates the sheath. It is set so as to be inclined toward the distal end side and obliquely intersect with respect to the axial direction of the portion 32. A predetermined position formed by the axis of the button accommodating portion 34 (pushing direction A1 of the push button 33) and the axis of the sheath accommodating portion 32 (extending direction of the outer sheath 22 in the housing 31 or extending direction of the lower side portion 31a). The angle θ1 can be set in a range larger than 0 ° and smaller than 90 °. The optimum value is set in relation to the ergonomic viewpoint and the configuration of the coil member 23 described later.

The tip end side (back side opposite to the opening side) of the button accommodating portion 34 communicates with a part (side surface) of the sheath accommodating portion 32 via the connection space 36. A base end portion of the leaf spring 33a is fixed to the tip of the push button 33. The tip side of the leaf spring 33a passes through the connection space 36, and in a state where the push button 33 is set to the first position (the state shown in FIG. 5A), the tip thereof slightly protrudes into the sheath accommodating portion 32. It is arranged like this.

A coil member 23 that forms a plurality of convex portions (or concave portions) on the surface of the outer sheath 22 on the proximal end side is attached. The coil member 23 is formed by winding a wire rod made of an elastic metal or the like having a substantially polygonal cross section in a coil shape, and the proximal end portion of the outer sheath 22 is fitted inside the coil member 23 to form the outer sheath. It is fixed to the sheath 22.

As the coil member 23, a wire rod having a substantially triangular cross section is wound around the coil in a coil shape so that a thread is formed as a convex portion on the surface side thereof. The coil member 23 is formed by winding a wire rod having a substantially rhombic cross section in a coil shape so that threads are formed on both the front surface side and the inner surface side thereof (like a so-called insert screw). You may use the one having the same structure.

When the push button 33 is pressed and pushed to the second position, the tip of the leaf spring 33a engages with the surface on the distal end side of one of the threads of the coil member 23 mounted on the outer sheath 22, and the outer sheath 22 is slid toward the proximal end side of the inner sheath 21 by a certain amount according to the stroke length of the push button 33.

When the pressure on the push button 33 is released, the push button 33 returns to the original first position by the urging force of the coil spring 35, and the tip of the leaf spring 33a engages with the coil member 23 mounted on the outer sheath 22 accordingly. Without doing so, the leaf spring 33a returns to its original position. By repeating pressing and releasing the push button 33, the outer sheath 22 can be slid toward the proximal end side with respect to the inner sheath 21 by a predetermined amount.

The feed amount of the coil member 23 (outer sheath 22) by pressing the push button 33 once is not particularly limited, but is, for example, 2.5 mm to 10 mm (for example, 2.5 mm, 5 mm, 7.5 mm, or 10 mm). The stroke length of the push button 33 can be a value corresponding to this.

As a method of attaching the coil member 23 to the proximal end of the outer sheath 22, the coil member 23 is expanded so that its inner diameter is slightly widened, and then the proximal end of the outer sheath 22 is inserted to form a coil. It can be fixed by reducing the diameter by the restoring force of the member 23. By arranging the threads on the inner surface side of the coil member 23, it can be securely fixed to the outer sheath 22 without using an adhesive or the like. However, it may be adhesively fixed with an adhesive or the like.

The longitudinal dimension of the coil member 23 is set to be larger than the stroke length (slide length of the outer sheath 22 with respect to the inner sheath 21) required to release the stent 5 arranged in the stent arrangement portion.

The position of the proximal end of the coil member 23 is such that the outer sheath 22 is pulled out by the maximum amount (that is, the distal end of the outer sheath 22 covers the stent 5 arranged in the stent arrangement portion 26). In the state), the push button 33 is set closer to the proximal end side than the portion where the tip of the leaf spring 33a is located in a state where no external force acts on the push button 33.

As for the position of the distal end of the coil member 23, the push button 33 is in a state where the outer sheath 22 is pulled in by the maximum amount (a state in which the proximal end of the outer sheath 22 is in contact with the bottom surface 32b of the sheath accommodating portion 32). It is set on the distal end side of the portion where the tip of the leaf spring 33a is located in a state where no external force acts.

In the present embodiment, as shown in FIG. 5B, when the push button 33 is pressed and pushed in, the tip of the leaf spring 33a engages with the surface of the coil member 23 on the distal end side of the screw thread. , The coil member 23 (outer sheath 22) is slid toward the proximal end side. When the push button 33 is released, the push button 33 returns to its original position due to the urging force of the coil spring 35 as shown in FIG. 5A. At this time, the tip of the leaf spring 33a interferes with the thread of the coil member 23. As a result, the coil member 23 (outer sheath 22) may slide (reverse) toward the distal end side. Therefore, in the present embodiment, a slide regulating means is provided in order to surely prevent the outer sheath 22 from sliding toward the distal end side.

That is, in the portion near the distal end on the lower side portion 31a side of the housing 31, the release switch 37 extends in the extending direction of the portion of the outer sheath 22 existing in the housing 31 (the axial direction of the sheath accommodating portion 32). It is held so that it can slide in a direction substantially parallel to. A switch accommodating portion 38 defining a substantially rectangular cuboid space is defined in the housing 31, and the longitudinal direction of the switch accommodating portion 38 is the axial direction of the sheath accommodating portion 32 (of the outer sheath 22). It is formed in a direction substantially parallel to the extending direction).

A substantially rectangular cuboid release switch 37 is slidably accommodated in the switch accommodating portion 38, and an operation protrusion 37a integrally formed with the release switch 37 is accommodated in the lower side portion of the switch accommodating portion 38. It is arranged so as to project through the opening 38a formed in a part of the 31a side.

By the operator's hand, the abdomen of the index finger, middle finger, ring finger and little finger (or one or more of them) is placed on the lower side portion 31a, and the portion near the base of the thumb and the portion of the palm near the base of the thumb is placed on the upper side. By arranging it on the portion 31b and gripping the housing 31 as described above, the operating protrusion 37a is pressed by the tip of the index finger toward the proximal end side or the distal end side along the longitudinal direction thereof. The release switch 37 can be slid.

The proximal end side of the switch accommodating portion 38 communicates with a part (side surface) of the sheath accommodating portion 32 via the connection space 36. At the proximal end of the release switch 37, a base end portion of a leaf spring 37b made of elastic metal or the like extending diagonally in the slide direction of the release switch 37 is fixed. The leaf spring 37b, in a state where the release switch 37 is set to a fixed position slid toward the proximal end side, has its tip passing through the connection space 36 and one distal end of the thread of the coil member 23. It is arranged so as to slightly protrude into the sheath accommodating portion 32 so as to engage with the side surface.

When the release switch 37 is set to the fixed position, the tip of the leaf spring 37b is engaged with the surface of the coil member 23 on the distal end side of the thread, so that the coil member 23 (outer sheath 22) is far away. Regulate the slide to the end side. When the coil member 23 (outer sheath 22) is slid toward the proximal end side, the tip of the leaf spring 37b is elastically deformed along the shape of the thread of the coil member 23 and escapes, so that the coil member 23 escapes. The slide of the (outer sheath 22) toward the proximal end side is not restricted.

When the release switch 37 is slid toward the distal end side and set to the release position, the base end side of the leaf spring 37b is elastically deformed with a part of the housing 31 as a fulcrum, and the coil member 23 of the leaf spring 37b at the tip thereof is elastically deformed. Is disengaged from the thread. Therefore, when the release switch 37 is set to the release position, the slide of the coil member 23 (outer sheath 22) to the distal end side is not restricted, and if necessary, the outer sheath 22 is moved to the distal end side. It becomes possible to slide to.

When the outer sheath 22 is pulled out from the housing 31 by the maximum amount (the state of FIG. 5A), the distal end of the outer sheath 22 reaches the distal end side of the stent 5, as shown in FIGS. 1A and 1C. In this state, the stent 5 arranged in the stent arrangement portion of the inner sheath 21 is held inside the stent 5 in a reduced diameter state.

When the push button 33 is repeatedly pressed and released a predetermined number of times from this state, the outer sheath 22 is slid toward the proximal end side with respect to the inner sheath 21, and the stent 5 is distal to the outer sheath 22. It is pushed out relatively from the edge and released (diameter expanded) by self-expanding force.

In the present embodiment, when the outer sheath 22 is pulled out from the housing 31 by the maximum amount (the state of FIG. 5A), the distal end of the outer sheath 22 is larger than the stent 5 as shown in FIGS. 1A and 1C. It is located on the distal end side and on the proximal end side of the balloon 27, and the balloon 27 is in an exposed state. However, the distal end of the outer sheath 22 is configured to reach the distal end side of the balloon 27 (for example, the position where it abuts on the base end of the tip tip 24), and the balloon 27 is also inside the outer sheath 22. It may be accommodated.

When the stent 5 is placed in the narrowed portion formed in the curved portion in the large intestine by using the stent delivery device 1 to which the stent 5 is mounted as described above, first, the stent delivery device is in a state where the balloon 27 is contracted. The catheter portion 2 of 1 is inserted into the large intestine via the treatment tool guide tube of the lower gastrointestinal endoscopy that is previously inserted into the large intestine from the anus. Next, while checking the X-ray contrast image, the catheter portion 2 is advanced, and the axial position of the stent 5 arranged in the stent placement portion 26 is set to an appropriate position with respect to the target stenosis portion. At the same time, the posture around the axis of the stent 5 is adjusted so as to match the state of curvature of the site where the stenosis is generated.

When the adjustment of the position and posture of the stent 5 is completed, the syringe (not shown) attached to the port 6e is operated to blow air into the balloon 27 through the balloon lumen 21b to inflate the balloon 27. As a result, the inflated balloon 27 is pressed against the inner wall of the intestinal tract, and the inner sheath 21 is fixed in the intestinal tract by the frictional force generated thereby. In this state, by sliding the outer sheath 22 in the pulling direction, the stent 5 is gradually released from the distal end side to expand its diameter, and the patency of the narrowed portion is ensured. After that, the balloon 27 is contracted and the catheter portion 2 is pulled out to complete a series of procedures.

The intestinal tract may be pulled toward the anus by pulling back the outer sheath 22 when the stent 5 is released. However, in the stent delivery device 1 of the present embodiment, the inner sheath 21 is moved to the back side of the stenosis by the balloon 27. Since it is fixed on the small intestine side), the positional relationship between the stenosis and the stent 5 is relatively small, and therefore the stent 5 can be accurately placed at the target position.

Further, in the stent 5 of the present embodiment, since the tubular portion 51 formed by connecting a plurality of annular units 51a in the axial direction is curved along the axial direction, the stent 5 is said to be placed in the curved portion of the digestive tract. By adjusting and indwelling the orientation of the stent 5 around the axis so as to match the curvature of the curved portion, the amount of deformation thereof can be reduced as compared with the conventional linearly formed stent. For this reason, the axial force (the force that the curved stent tries to restore to its original shape), which increases roughly in proportion to the amount of deformation, also decreases by that amount, and both ends (tip and tip) on the dorsal side of the stent 5 The load on the inner wall of the intestinal tract (at the proximal end) can be reduced. Therefore, the risk of ulcers and perforations in the inner wall of the intestinal tract can be reduced.

The embodiments described above are described for facilitating the understanding of the present invention, and are not described for limiting the present invention. Therefore, each element disclosed in the above-described embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

1 ... Stent delivery device 2 ... Catheter part 21 ... Inner sheath 21a ... Guide wire lumen 21b ... Balloon lumen (supply / discharge path)
21c ... Opening 22 ... Outer sheath 23 ... Coil member 24 ... Tip tip 25 ... Fixing ring 25a ... Contrast marker 26 ... Stent placement part 27 ... Balloon 27a, 27b ... Joint part 27c ... Expansion part 3 ... Operation part 31 ... Housing 32 ... Sheath accommodating part 33 ... Push button 34 ... Button accommodating part 35 ... Coil spring 36 ... Connection space 37 ... Release switch 4 ... Guide wire 5 ... Stent 51 ... Tubular body 51a ... Annular unit 51b ... Connection part 51c ... Contrast marker 51d, 51e ... Bending part 6a ... Cover 6b, 6d ... Branch tube 6c, 6e ... Port AX ... Central axis of stent

Claims (1)

A stent delivery device that indwells a stent with an outer diameter of 10 to 40 mm in the large intestine.
A stent placement portion for placing the stent on the outer peripheral surface near the distal end, and an opening on the side portion on the distal end side of the stent placement portion to supply and drain fluid from the proximal end side. An inner sheath with a supply / discharge path and
An outer sheath in which the inner sheath is slidably inserted and the stent placed in the stent placement portion is held in a reduced diameter state.
The inner sheath has a balloon provided so as to surround an opening on the distal end side of the supply / discharge passage, and expands or contracts when fluid is supplied / discharged through the supply / discharge passage.
The outer diameter of the balloon when inflated is 10 to 100 mm, and the balloon has an outer diameter of 10 to 100 mm.
The balloon is formed of an elastic material and has a tubular shape as a whole in a contracted state, and includes a substantially cylindrical joint portion formed at both ends of the balloon and joined to the outer peripheral surface of the inner sheath. At the same time, it is provided with an expansion portion formed between the joints at both ends and expanded by supplying a fluid to the inside.
The expanded portion is formed in a rotating body shape in which a convex curve is rotated outward with the axis of the inner sheath as a rotation axis in a state where it does not receive an external force, and a state where it does not receive an external force. The maximum outer diameter of the stent delivery device is 110 to 200% of the outer diameter of the joint.

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