JP2019170520A - Stent delivery device - Google Patents

Abstract

To provide a stent delivery device capable of placing a stent at a target position accurately.SOLUTION: A stent delivery device for placing a stent 5 in a lumen includes: an inner sheath 21 having a stent arrangement part for arranging the stent 5 on an outer peripheral surface in the vicinity of the distal end, and a supply and discharge passage open to a side on a distal end side as compared with the arrangement part, for supplying and discharging fluid from a proximal end side; an outer sheath 22 into which the inner sheath 21 is slidably inserted for holding the stent 5 arranged in the stent arrangement part in a diameter-contracted state; and a balloon 27 provided so as to surround the opening on the distal end side of the supply and discharge passage of the inner sheath 21, which inflates or contracts when the fluid is supplied or discharged through the supply and discharge passage.SELECTED DRAWING: Figure 1C

Description

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

  In order to ensure the patency of a body lumen such as a digestive tract or a blood vessel, a medical method is known in which a stent is placed in a stenosis or occlusion (hereinafter referred to simply as a stenosis). As a device for placing a self-expanding stent in a lumen, for example, a stent delivery device described in Patent Document 1 is known.

  This stent delivery device has an inner sheath and an outer sheath through which the inner sheath is slidably inserted. The stent is placed in a stent placement portion provided near the distal end of the inner sheath, and the outer sheath The stent is held in an elastically contracted state inside the vicinity of its distal end. Then, the stent is released from the outer sheath by operating the operating portion provided on the proximal end side and sliding it toward the proximal end side so that the outer sheath is pulled back with respect to the inner sheath. The stent is expanded by an expansion force and released.

  By the way, the stent needs to be accurately placed at a target position (stenosis) in the lumen. However, for example, when a stent delivery catheter is inserted into the large intestine via the lower gastrointestinal tract endoscope and the stent is placed in the stenosis of the large intestine, the stent is positioned more than the target position where the operator plans to place the stent. It has been reported that there is a case where it is deviated from the back side (small intestine side).

  For example, when the stent is placed in the stenosis of the transverse colon of the large intestine, unlike the ascending colon, descending colon, rectum, etc., the transverse colon is not fixed to the peritoneum, so when releasing the stent When the intestinal tract is released while being pulled toward the near side (anus) by friction between the outer sheath and the inner wall of the intestinal tract, as a result, the intestinal tract may be left behind (small intestine) from the target position. It is a cause.

JP 2012-139471 A

  This invention is made | formed in view of such a point, and it aims at providing the stent delivery apparatus which can be correctly detained in the position which aimed the stent.

In order to achieve the above object, a stent delivery device according to the present invention comprises:
A stent delivery device for placing a stent in a lumen,
A stent placement portion for placing the stent on the outer peripheral surface in the vicinity of the distal end, and an opening in the side portion on the distal end side relative to the stent placement portion, for supplying and discharging fluid from the proximal end side An inner sheath with a supply / discharge path;
An outer sheath that is slidably inserted through the inner sheath and that holds the stent disposed in the stent placement portion in a reduced diameter state; and
A stent delivery device comprising: a balloon that is provided so as to surround an opening on a distal end side of the supply / discharge path of the inner sheath, and inflates or contracts when fluid is supplied / discharged through the supply / discharge path; is there.

  When a stent is placed in a lumen using the stent delivery device according to the present invention, first, the stent held in the outer sheath is arranged 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 using the frictional force between the balloon and the lumen wall. Thereafter, the outer sheath is slid toward the proximal end side to release the stent. When releasing the stent, even if the lumen wall is pulled to the near side due to friction between the outer sheath and the inner surface of the lumen wall, the inner sheath is fixed in the lumen at the balloon part. The relative position between the lumen and the stent is little changed, and as a result, the stent can be accurately placed at the target position.

FIG. 1A is a front view showing an overall configuration of a stent delivery device according to an embodiment of the present invention. 1B is a cross-sectional view taken along line Ib-Ib in 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 where the outer sheath of FIG. 1C is slid to the proximal end side to expose the stent placement 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 expanded view showing an enlarged end portion of the stent of FIG. 2A. FIG. 2C is a partially enlarged view showing IIc part of FIG. 2B in an enlarged manner. FIG. 3A is a view showing a cylindrical body used for manufacturing the stent of FIG. 2A. FIG. 3B is a diagram showing a straight tubular mesh-like cylinder obtained by laser cutting the cylinder shown in 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 illustrating a configuration of an operation unit of the stent delivery device of FIG. 1A and illustrates a state in which a push button is not pressed. FIG. 5B is a diagram illustrating a state where the push button of FIG. 5A is pressed and pushed.

  Hereinafter, an embodiment of a stent delivery device according to the present invention will be described with reference to the drawings. The stent delivery device of this embodiment uses an endoscope to place a self-expanding stent in the stenosis in order to ensure the patency of the stenosis of the large intestine that is stenotic due to a tumor or the like. It is a stent delivery device for the large intestine used for this purpose.

  The stent delivery device according to the present invention can be particularly suitably used as a colonic stent delivery device for placing a stent in the large intestine where it is particularly difficult to place the stent accurately at a position where the stent is aimed. However, the stent delivery device according to the present invention is not limited to the large intestine, but other stents for ensuring the patency of other digestive tracts such as the small intestine, duodenum, and bile duct, as well as ureters, blood vessels, and other lumens. It can be used as a device.

  First, refer to FIG. 1A. The stent delivery device 1 is connected to a proximal end side of an elongated catheter part 2 inserted into a patient's body (lumen) and the proximal end side of the catheter part 2 through a treatment instrument guide tube of an endoscope (not shown). An operation part (handle) 3 for operating the catheter part 2 inside the body from the outside and a self-expanding stent 5 as an indwelling target are roughly provided.

  The catheter unit 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 omitted, but the outer sheath 22 is actually a distal end to a proximal end. It is a tubular body without any defects.

  The inner sheath 21 is composed of an elongated tube having flexibility, and has a guide wire lumen 21a and a balloon lumen (supply / discharge passage) 21b that do not communicate with each other inside (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 the guide wire 4 used as a guide for inserting the catheter portion 2 into the patient's body is inserted. After the guide wire 4 is inserted into the body to secure a path between the outside of the body and the inside of the body, the catheter portion 2 is pushed (advanced) along the guide wire 4 so that the distal end side of the catheter portion 2 is positioned within 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 contrast in the body, or as a flow path for supplying physiological saline or the like as necessary.

  The balloon lumen 21b is a lumen that circulates fluid (in this embodiment, air) for inflating or deflating a balloon 27, which will be described later, and its distal end side reaches the distal end of the inner sheath 21. The inner sheath 21 has an opening at the side near the distal end. The opening 21c on the distal end side of the balloon lumen 21b is provided on the distal end side with respect to the stent placement portion 26 described later (see FIG. 1D).

  A distal end tip 24 formed in a tapered shape is attached to the distal end of the inner sheath 21. The distal tip 24 has a lumen communicating with the distal end of the guide wire lumen 21a of the inner sheath 21 and an opening 24a. The distal tip 24 plays a role of reducing insertion resistance of the catheter part 2 and facilitating insertion into the body, such as polyamide, polyamide elastomer, polyurethane, fluorine resin such as polytetrafluoroethylene, and polyethylene. 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 this fixing ring 25 is for defining the position of the proximal end of the stent 5. A predetermined portion on the distal end side is a stent placement portion 26 (see FIG. 1D). In the stent placement portion 26, the stent 5 is placed so as to cover the inner sheath 21.

  A contrast marker (contrast marker for detecting the position around the axis) 25 a for detecting the posture around the central axis of the inner sheath 21 is provided in a part of the inner sheath 21 in the circumferential direction of the fixing ring 25. In this embodiment, the contrast marker 25a for detecting the attitude around the axis is provided on the fixing ring 25, but is provided not on the fixing ring 25 but on a portion of the inner sheath 21 in the circumferential direction of the stent placement portion 26 or its vicinity. May be.

  The contrast marker for detecting the attitude around the axis may be provided on the stent 5 as will be described in detail later. In this case, the contrast marker 25a for detecting the attitude around the axis of the inner sheath 21 may be omitted. In addition, although not shown, a contrast marker (axial contrast marker for axial position detection) for detecting a position in the direction along the central axis may be provided near the distal end of the inner sheath 21.

  These contrast marker 25a for detecting the posture around the axis and the contrast marker for detecting the axial position are detected as images by X-ray contrast and become labels in the body. For example, gold, platinum, platinum iridium alloy, platinum, Silver, stainless steel, or the like can be used. These contrast markers 25a may be constituted by a resin molded product containing powder of an X-ray contrast material. As the powder of the X-ray contrast material used for these contrast markers 25a, barium sulfate powder, bismuth subcarbonate powder, tungsten powder, the above-described 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 distal 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 fluid (air in this embodiment) is supplied (injected) therein, and contracts when discharged (sucked). The balloon 27 is a rotating body-shaped balloon having the axis of the inner sheath 21 as a rotation axis. The inner sheath 21 can be releasably fixed in the large intestine by the frictional force generated when the inflated balloon 27 is pressed against the inner wall of the large intestine.

  As a material for forming the balloon 27, a stretchable material is suitable, and in particular, a material having a 100% modulus (measured according to JIS K 6251) of 0.1 to 10 MPa is preferable, and 1 to 5 MPa. Are particularly preferred. 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 expanded to a sufficient size. 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 in a deflated state as a whole, and has a cylindrical shape as a whole, and substantially cylindrical joint portions 27a and 27b that are joined to the outer peripheral surface of the inner sheath 21 are formed at both ends thereof. Between the joint portions 27a and 27b, an expansion portion 27c is formed which expands when a fluid is supplied to the inside. The inflating portion 27c of the balloon 27 is in a state where no external force is received (the fluid is not supplied to the inside and the internal pressure is balanced with the external air pressure and the balloon 27 is contracted). A rotating body is 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 inflated balloon 27 can more firmly fix the inner sheath 21 to the large intestine. The method for joining the joint portions 27a and 27b of the balloon 27 and the inner sheath 21 is not particularly limited. For example, bonding with an adhesive, thermal fusion, welding with a solvent, ultrasonic fusion, high-frequency fusion, etc. Can be mentioned.

  The inflating portion 27c of the balloon 27 preferably has a maximum outer diameter of 110 to 200% of the outer diameter of the joint portion 27b in a state where no external force is applied. If this ratio is too small, there is a risk that the effect of improving the firmness of fixation to the large intestine may not be sufficiently obtained. If it is too large, the balloon 27 may be in a deflated state when the balloon catheter 1 is inserted into the body. May get in the way.

  Further, the outer diameter of the balloon 27 (inflatable portion 27c) at the time of inflation may vary depending on the pressure of the fluid supplied to the inside. It is preferable to set within the range. Further, the length of the inflatable portion 27c in 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 method for forming the stretchable material, but it is preferable to use a dipping method. In the dipping molding method, a stretchable material and various additives as necessary 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). It is immersed and a solution (suspension) is applied to the surface of the mold, and the solvent is evaporated to form a film on the surface of the mold. By repeating this immersion and drying, a balloon having a desired thickness can be formed. Depending on the type of stretchable material, crosslinking is performed after film formation, if necessary.

  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 the inner sheath 21 is slidably inserted into the inner 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 is slidable (relatively moved) in the axial direction with respect to the inner sheath 21 by operating the operation unit 3. In addition, although illustration is abbreviate | omitted in the distal end vicinity of the outer sheath 22, the contrast marker (contrast marker for axial direction position detection) for detecting the position of the direction along a central axis may be provided.

  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 copolymer, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamide, and polyether polyamide. , Polyester polyamide, polyetheretherketone, polyetherimide, various resin materials such as polytetrafluoroethylene and fluororesin such as tetrafluoroethylene / hexafluoropropylene copolymer, polystyrene, polyolefin, polyurethane, polyester It is possible to use various thermoplastic elastomers such as those based on polyamide, polyamide and polybutadiene. Two or more of these can be used in combination.

  In some cases, the outer sheath 22 is provided with a mantle tube made of a flexible elongated tube through which the outer sheath 22 is slidably inserted. However, in this embodiment, the mantle tube is not provided.

  When the stent delivery device 1 is inserted into the body, the guide wire 4 is inserted into the guide wire lumen 21a (see FIG. 1B) of the inner sheath 21, and its distal end is the distal end of the distal tip 24 of the inner sheath 21. The proximal end protrudes outwardly through a branch pipe 6b and a port 6c connected to the proximal end of the inner sheath 21 disposed through the operation portion 3. Arranged to be exposed.

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

  The stent 5 has a tubular portion 51 that has a tubular shape. The tubular part 51 has a plurality of ring-shaped (endless circular) annular units 51a, and has a structure in which a plurality of annular units 51a are connected along a central axis AX set in a predetermined curved shape. Yes. 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 extending in the circumferential direction while being repeatedly bent. 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. The first bent portion 51d and the second bent portion 51e 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 to the other second bent portion 51e. As shown in FIG. 2B, which is a development view of the stent 5, each annular unit 51a has 20 first bent portions 51d and 20 second bent portions 51e, and the adjacent annular units 51a are arranged in the circumferential direction. They are 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 flexibly connects the annular units 51a so that the adjacent annular units 51a can be moved relative to each other. However, the number of the first bent portions 51d and the second bent portions 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 sides of the annular units 51a arranged at both ends of the stent 5 are provided with a plurality of eyelets formed in a substantially annular shape instead of the connecting portions 51b. The contrast markers 51c formed in a substantially disc shape are respectively fitted and joined to the eyelets. These contrast markers 51c are for detecting the axial position of the stent 5 in the lumen by X-ray contrast or the like. The presence or absence of the contrast marker 51c in the stent 5, the shape, 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, these contrast markers 51c are uniformly arranged in the circumferential direction of the annular unit 51a arranged at both ends of the stent 5, and therefore the posture around the axis of the stent 5 is set. It is difficult to detect. For this reason, you may comprise so that the attitude | position around the axis | shaft of the stent 5 may be detected by making the shape and structure mutually differ between these contrast markers 51c, or devising arrangement | positioning.

  The wire diameter of the wire constituting the annular unit 51a of the stent 5 is preferably about 0.05 to 1 mm. Moreover, when the cross section of a wire is a strip | belt shaped object with a rectangular cross section, the length of a long side direction is 0.1-1 mm, for example, and the length of a short side direction is about 0.05-0.5 mm. It 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, it is preferable that the outer diameter is 10 to 40 mm and the length is 20 to 200 mm. However, the outer dimensions of the stent 5 may be optimized depending on the size of the body lumen in which the stent 5 is placed, and for example, the outer diameter is set in a range of 2 to 40 mm and a length 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-mentioned value by elastically deforming the stent 5 when the stent 5 is conveyed to the indwelling site by the stent delivery device 1. It is stored 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 to the original state by the self-expanding force from the contracted state due to elastic deformation. Specific examples include a nickel titanium (Ni-Ti) alloy, stainless steel Metals such as steel, tantalum, titanium, cobalt chromium alloy, and magnesium alloy are listed. In the present embodiment, the stent 5 is formed of a Ni—Ti alloy that is a superelastic alloy.

  The stent 5 of this embodiment can be manufactured as follows. First, as shown in FIG. 3A, a cylindrical body (pipe) 52 formed of a material for forming the stent 5 is prepared. Next, 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. Thereafter, as shown in FIG. 3C, the mandrel 54 having a desired curved shape is inserted into the lumen of the mesh-like cylinder 53 of FIG. 3B, and the mesh-like cylinder 53 is made into the curved shape of the mandrel 54. In this state, heat treatment is performed for a predetermined time in a predetermined temperature environment to perform shaping (shape memory). After the shaping, the mandrel 54 is pulled out and subjected to polishing such as electropolishing or attaching a marker, and as shown in FIG. 2A, the stent has a shape curved in the axial direction without external force acting. 5 is manufactured.

  The stent 5 is placed in the stent placement portion 26 in a state of being deformed substantially linearly by inserting the stent placement portion 26 of the inner sheath 21 into the lumen thereof, and the outer sheath 22 is placed in a state where the diameter is reduced. By sliding to the distal end side, the outer sheath 22 is accommodated.

  When the stent 5 is placed on the stent placement 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 posture around the axis. Specifically, for example, the posture around the axis of the stent 5 is adjusted so that the dorsal side (or 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. Accordingly, when the stent 5 is placed in the stenosis portion generated in the curved portion of the large intestine, the posture around the axis of the contrast marker 25a is confirmed, so that the posture is curved corresponding to the curvature of the stenosis portion. Further, the posture adjustment around the axis of the stent 5 can be performed. As described above, if the contrast marker for detecting the posture around the axis is provided on the stent 5, the posture adjustment work when the stent 5 is mounted on the stent placement portion 26 can be eliminated, which is convenient.

  As shown in FIG. 2A, the shape of the stent 5 is approximately a quarter arc shape as shown in FIG. 2A. However, this is only an example, and is appropriate depending on the shape of the site where the stent 5 is to be placed. Can be used, and a linear stent can also be used. Further, even when a curved stent is used, for example, a substantially three-quarter arc-shaped stent 5 ′ as shown in FIG. 4 may be used. It may be arcuate or other arcuate. Moreover, not only circular arc shape but other curvilinear shapes, such as a parabola, and these combination may be sufficient. You may arrange | position the linear part formed in the substantially linear form at the one end or both ends of the stent 5. FIG. Further, it may be substantially S-shaped.

  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 part 3 has a handle that is a means for the operator to grip the stent 5 and perform a release operation of the stent 5. The housing 31 constituting the handle has a substantially linear lower side 31a so that the index finger, middle finger, ring finger and little finger (or one or more of these) can be placed when gripped by the operator's hand, It has an upper side portion 31b having a concave portion having a loose arcuate shape so that a portion of the base of the thumb and a portion near the base of the thumb of the palm can be arranged.

  The housing 31 has a sheath housing portion 32 that defines a substantially cylindrical space into which the proximal ends of the inner sheath 21 and the outer sheath 22 are drawn. The distal end of the sheath housing portion 32 is an opening 32a for drawing these sheaths 21 and 22, and the proximal end of the sheath housing portion 32 is brought into contact with the proximal end of the outer sheath 22, and the outer The sheath 22 is closed by a bottom surface 32b that defines a stroke end when the sheath 22 is slid. A through hole is formed in the central portion of the bottom surface 32b, and the proximal end of the inner sheath 21 passes through the through hole and is fixed to 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 penetrating through the through hole of the bottom surface 32b of the housing 31, as shown in FIG. 1A. The branch pipe 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 pipe 6d is a balloon whose inner end is the inner sheath 21. It is 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 a polymer material is preferably used.

  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 from the opening of the port 6 c and can be inserted into the guide wire lumen 21 a 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 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 fluid (in this embodiment, air) for inflating or deflating 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 connection method between 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. For example, the distal ends of the branch pipes 6b and 6d are tapered. What is necessary is just to adhere | attach by shape | molding, apply | coating an adhesive agent to the outer peripheral surface, and inserting the edge part into the lumen | rumen 21a, 21b corresponding to the inner sheath 21. FIG.

  Connection portions between the inner sheath 21 and the branch pipes 6b and 6d are 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 a box shape or a cylinder shape. The material of the cover 6a is not particularly limited, but a polymer material is preferably used. It is also possible to use a heat-shrinkable tube as the cover 6a.

  At a portion near the distal end of the upper side portion 31b of the housing 31, the push button 33 is a predetermined angle θ1 in the extending direction of the portion existing in the housing 31 of the outer sheath 22 (the axial center direction of the sheath housing portion 32). Is held so as to be slidable in the intersecting direction A1. That is, the housing 31 is provided with a button accommodating portion 34 that defines a substantially cylindrical space. The axial direction A1 of the button accommodating portion 34 is the axial direction (outer outer) of the sheath accommodating portion 32. The sheath 22 is formed so as to substantially coincide with the direction intersecting with the predetermined angle θ1.

  The front end side of a substantially cylindrical push button 33 is inserted into the opening side of the button accommodating portion 34, and the push button 33 is held so as to be slidable 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 preventing the push button 33 from coming out of the button accommodating portion 34 by engaging with a part of the button accommodating portion 34. ing. A spring support portion 34 a is provided at an intermediate portion of the button accommodating portion 34, and a coil spring 35 is interposed between one surface of the spring support portion 34 a and the tip surface of the push button 33.

  When an external force does not act (when the push button 33 is not pushed so as to be pushed into the button housing portion 34), as shown in FIG. 5A, the push button 33 is separated from the outer sheath 22 at a predetermined first position (described above) It is urged by the coil spring 35 so as to be located at a position defined by the prevention mechanism. When the push button 33 is pressed so as to be pushed into the button accommodating portion 34, the outer sheath is more resistant than the first position against the urging force of the coil spring 35, as shown in FIG. 5B. It is possible to move to a predetermined second position close to 22.

  When the push on the push button 33 is released, the push button 33 returns to the original first position by the biasing 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 is arranged by placing the abdomen of the index finger, middle finger, ring finger and little finger (or one or more of them) on the lower side 31a by the operator's hand, and the base of the thumb and the base of the thumb of the palm. In the state where the vicinity portion of the thumb is placed and gripped on the upper side portion 31b, the thumb can be pushed or released by the belly of the tip of the thumb (the portion ahead of the first joint) by bending and extending the thumb. Yes.

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

  The push-in amount (stroke length) of the push button 33 is set to an optimal value in relation to the ergonomic viewpoint described above and the feed amount of the coil member 23 (outer sheath 22) by one press of the push button 33. The

  Similarly, in consideration of the fact that the push button 33 can be pressed and released by the thumb without ergonomic stress, the axial center direction (slide direction of the push button 33) A1 of the button housing portion 34 is the sheath housing. With respect to the axial direction of the part 32, it is set so as to be inclined and inclined toward the distal end side. Predetermined between the axial center of the button housing portion 34 (the pushing direction A1 of the push button 33) and the axial center of the sheath housing portion 32 (the extending direction of the outer sheath 22 in the housing 31 or the 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 distal end side (the back side opposite to the opening side) of the button accommodating portion 34 is communicated with a part (side surface) of the sheath accommodating portion 32 via the connection space 36. A proximal end portion of a leaf spring 33 a is fixed to the distal end of the push button 33. The distal end side of the leaf spring 33a passes through the connection space 36, and the distal end slightly protrudes into the sheath housing portion 32 in a state where the push button 33 is set to the first position (the state shown in FIG. 5A). Are arranged as follows.

  A coil member 23 that forms a plurality of convex portions (or concave portions) on the surface thereof is attached to a part of the outer sheath 22 on the proximal end side. The coil member 23 is configured by winding a wire made of an elastic metal or the like having a substantially polygonal cross section into a coil shape, and the outer end of the outer sheath 22 is inserted into the outer sheath 22 so that the outer It is fixed to the sheath 22.

  As the coil member 23, it is possible to use one in which a thread is formed as a convex portion on the surface side by winding a wire having a substantially triangular cross section into a coil shape. As the coil member 23, a wire rod having a substantially rhombus cross section is wound in a coil shape so that threads are formed on both the surface side and the inner surface side thereof (such as a so-called insert screw). May be used.

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

  When the push on the push button 33 is released, the push button 33 returns to the original first position due to the biasing force of the coil spring 35, and the tip of the leaf spring 33a is engaged with the coil member 23 attached to the outer sheath 22 accordingly. Without this, the leaf spring 33a returns to its original position. By repeatedly pressing and releasing the push button 33, the outer sheath 22 can be slid to the proximal end side by a predetermined amount with respect to the inner sheath 21.

  The feed amount of the coil member 23 (outer sheath 22) by one press of the push button 33 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 is a value corresponding to this.

  As a method for attaching the coil member 23 to the proximal end portion of the outer sheath 22, the proximal end portion of the outer sheath 22 is inserted in a state where the coil member 23 is expanded so that the inner diameter thereof slightly expands, and the coil By reducing the diameter by the restoring force of the member 23, the member 23 can be fixed. By arranging the screw thread on the inner surface side of the coil member 23, the coil member 23 can be reliably fixed to the outer sheath 22 without using an adhesive or the like. However, it may be bonded and fixed with an adhesive or the like.

  The dimension in the longitudinal direction of the coil member 23 is set to be larger than the stroke length (sliding length of the outer sheath 22 with respect to the inner sheath 21) necessary for releasing the stent 5 disposed in the stent placement portion.

  The position of the proximal end of the coil member 23 is the state in which the outer sheath 22 is pulled out to the maximum amount (that is, the distal end portion of the outer sheath 22 is disposed so as to cover the stent 5 disposed in the stent placement 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 is applied.

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

  In this embodiment, as shown in FIG. 5B, when the push button 33 is pressed and pushed, the tip of the leaf spring 33a is engaged with the surface of the coil member 23 on the distal end side of the thread. The coil member 23 (outer sheath 22) is slid to the proximal end side. When the push button 33 is released, the push button 33 returns to the original state as shown in FIG. 5A by the urging force of the coil spring 35. At this time, the tip of the leaf spring 33a interferes with the thread of the coil member 23. Then, the coil member 23 (outer sheath 22) may slide (reverse) to the distal end side. Therefore, in the present embodiment, a slide restricting means is provided in order to reliably prevent unexpected sliding of the outer sheath 22 toward the distal end side.

  That is, the release switch 37 is provided at the portion near the distal end on the lower side portion 31a side of the housing 31 in the extending direction of the portion of the outer sheath 22 in the housing 31 (the axial center direction of the sheath housing portion 32). Is slidably held in a direction substantially parallel to. The housing 31 has a switch housing portion 38 that defines a substantially rectangular parallelepiped space. The switch housing portion 38 has a longitudinal direction in the axial direction of the sheath housing portion 32 (the outer sheath 22 of the outer sheath 22). It is formed in a direction substantially parallel to the extending direction).

  A substantially rectangular parallelepiped release switch 37 is housed in the switch housing portion 38 so as to be slidable along the longitudinal direction, and an operation projection 37 a formed integrally with the release switch 37 is a lower side portion of the switch housing portion 38. It arrange | positions so that it may pass through the opening 38a formed in a part on the 31a side, and may protrude.

  By the surgeon's hand, the stomach of the index finger, middle finger, ring finger and little finger (or one or more of them) is placed on the lower side 31a, and the base part of the thumb and the part near the base of the thumb of the palm are placed on the upper side In the state where the housing 31 is gripped as described above, the operation protrusion 37a is pressed toward the proximal end side or the distal end side along the longitudinal direction at the distal end portion of the index finger with the housing 31 gripped as described above, The release switch 37 can be slid.

  The proximal end side of the switch housing portion 38 is communicated with a part (side surface) of the sheath housing portion 32 through the connection space 36. At the proximal end of the release switch 37, a base end portion of a leaf spring 37b made of an elastic metal or the like that extends obliquely in the sliding direction of the release switch 37 is fixed. When the release switch 37 is set at a fixed position where the release switch 37 is slid to the proximal end side, the tip of the leaf spring 37 b passes through the connection space 36 and is one distal end of the thread of the coil member 23. It arrange | positions so that it may protrude slightly in the sheath accommodating part 32 so that the surface of a side may be engaged.

  In a state where the release switch 37 is set to the fixed position, the distal end of the leaf spring 37b is engaged with the surface of the coil member 23 on the distal end side of the screw thread, so that the coil member 23 (outer sheath 22) is distant. Regulates sliding toward the distal end. When the coil member 23 (outer sheath 22) is slid to the proximal end side, the distal end portion of the leaf spring 37b is elastically deformed along the shape of the thread of the coil member 23, so that the coil member 23 escapes. The sliding of the (outer sheath 22) toward the proximal end side is not restricted.

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

  In a state where the outer sheath 22 is pulled out from the housing 31 in the maximum amount (the state shown in FIG. 5A), the distal end of the outer sheath 22 reaches the distal end side relative to the stent 5 as shown in FIGS. 1A and 1C. In this state, the stent 5 placed in the stent placement portion of the inner sheath 21 is held in its reduced 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 moved to the distal side of the outer sheath 22. It is pushed out relatively from the end and released (expanded diameter) 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 shown in FIG. 5A), the distal end of the outer sheath 22 is more than the stent 5 as shown in FIGS. 1A and 1C. The distal end side is located closer to the proximal end side than the balloon 27, and the balloon 27 is exposed. However, the distal end of the outer sheath 22 is configured to reach the distal end side of the balloon 27 (for example, a position that contacts the proximal end of the distal tip 24), and the balloon 27 is also placed in the outer sheath 22. It may be accommodated.

  When the stent 5 is placed in a stenosis portion generated in a curved portion in the large intestine using the stent delivery device 1 to which the above-described stent 5 is attached, the stent delivery device is first in a state where the balloon 27 is deflated. 1 catheter part 2 is inserted into the large intestine via the treatment instrument guide tube of the lower gastrointestinal tract endoscope that has been previously inserted into the large intestine from the anus. Next, while confirming the X-ray contrast image, the catheter portion 2 is advanced, and the axial position of the stent 5 placed 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 conform to the curved state of the site where the stenosis occurs.

  When the adjustment of the position and posture of the stent 5 is completed, a syringe (not shown) attached to the port 6e is operated to send air into the balloon 27 through the balloon lumen 21b, thereby inflating the balloon 27. Thereby, 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, the outer sheath 22 is slid in the direction of pulling back, so that the stent 5 is gradually released from the distal end side to expand its diameter, and the patency of the narrowed portion is ensured. Thereafter, the balloon 27 is deflated and the catheter part 2 is pulled out, thereby completing a series of procedures.

  In some cases, the intestinal tract may be pulled to the anal side by pulling back the outer sheath 22 when the stent 5 is released. In the stent delivery device 1 of the present embodiment, the inner sheath 21 is moved to the far side of the stenosis portion by the balloon 27 ( Since it is fixed on the small intestine side, the positional relationship between the stenosis portion and the stent 5 hardly changes relatively, and therefore, the stent 5 can be accurately placed at a 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, when the stent is placed in the curved portion of the digestive tract, By adjusting and indwelling the posture around the axis of the stent 5 so as to conform to the bending of the bending portion, the amount of deformation can be reduced as compared to a conventional linearly formed stent. For this reason, the axial force (the force that the bent stent tries to restore to the original shape) that increases in proportion to the amount of deformation is also reduced by that amount, and both ends of the back side of the stent 5 (the tip and The load on the intestinal inner wall of the proximal end portion can be reduced. Therefore, the risk of ulcers and perforations occurring on the inner wall of the intestine can be reduced.

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

DESCRIPTION OF SYMBOLS 1 ... Stent delivery apparatus 2 ... Catheter part 21 ... Inner sheath 21a ... Guide wire lumen 21b ... Balloon lumen (supply / discharge route)
21c ... Open 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 ... Operating 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 pipe 6c, 6e ... port AX ... central axis of stent

Claims (1)

A stent delivery device for placing a stent in a lumen,
A stent placement portion for placing the stent on the outer peripheral surface in the vicinity of the distal end, and an opening in the side portion on the distal end side relative to the stent placement portion, for supplying and discharging fluid from the proximal end side An inner sheath with a supply / discharge path;
An outer sheath that is slidably inserted through the inner sheath and that holds the stent disposed in the stent placement portion in a reduced diameter state; and
A stent delivery device comprising: a balloon provided to surround an opening on a distal end side of the supply / discharge path of the inner sheath, and inflated or deflated when fluid is supplied / discharged through the supply / discharge path.

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