Patent ID: 12239576

DESCRIPTION OF THE EMBODIMENTS

Modes for carrying out the present invention will be described below with reference to the drawings. The present invention is not limited to the modes described below, and includes those appropriately modified by a person skilled in the art within a scope obvious from the following modes.

FIG.1is a conceptual diagram showing an example of the stent. As shown inFIG.1, the stent comprises a tubular body part3and a tip portion5located at the tip of the body part3. Examples of the stent include stents for use in the field of ophthalmology, including nasolacrimal duct stents, conjunctival nasal cavity stents, and conjunctival lacrimal stents; stents for use in the field of brain surgery, including Monro foramen stents and cerebral aqueduct stents; stents for use in the field of otolaryngology, including eustachian tube stents; stents for use in the field of urology, including bile duct stents; stents for use in digestive organs, including anal stents; stents for use in the field of urology, including ureteral stents; and stents for use in the field of gynecology and obstetrics, including fallopian tube stents; and stents for use in the respiratory field. When the stent is a nasolacrimal duct stent for nasolacrimal duct, the diameter thereof is, for example, 2 mm or more and 8 mm or less, and may be 3 mm or more and 7 mm or less, or 4 mm or more and 6 mm or less. Hereinafter, a lacrimal stent will be mainly described. The body part3is the main body of the stent to be placed in the body. The tip portion is a portion into which the stent is inserted. In the case of a lacrimal stent, the tip portion is located in the upward direction. A nasolacrimal duct stent is a stent to be placed in the nasolacrimal duct.

The tip portion5becomes wider toward the tip. The tip means a tip direction, and in the case of a lacrimal stent, the tip direction is the upward direction or downward direction. Since the tip portion5becomes wider toward the tip as described above, occlusion caused by granulation can be prevented after the stent is placed. The tip portion5, which becomes wider toward the tip, may be present at both ends of the stent, or may be present at only one end. The diameter (maximum diameter) of the tip portion5(when having a circular outer periphery) is, for example, 1.05 times to 2 times the diameter of the body part3(when having a circular outer periphery), and may be 1.5 times to 2 times, 1.6 times to 1.9 times, 1.1 times or more and 1.3 times or less, or 1.2 times or more and 1.3 times or less. The tip portion5may have a circular shape with a diameter gradually increasing toward the tip, like a petal, or may be oval or rugby ball-shaped. From the viewpoint of preventing granulation and preventing removal due to frictional resistance, the tip portion5preferably has an irregular surface (particularly on the body surface side), and the tip portion5may have a mesh-like shape.

The example shown inFIG.1has an extension part21extending from the tip portion5. The tip of the extension part21may be configured to become narrower toward the tip. The tip of the extension part21may have a tubular shape with the same width as the body part, or may be tapered.

As the body part3, one similar to that of a known lacrimal stent can be used. On the other hand, from the viewpoint of ensuring tissue metabolism, the body part3preferably has a mesh-like shape. If the body part3is occluded, metabolism such as respiration of the tissue in close contact with the body part3is inhibited. For the mesh-like shape, a known structure used for a known stent can be adopted. The body part3may have a plurality of holes. The body part3may be formed from a shape memory alloy.

FIG.2is an enlarged example of the tip portion of the stent. The stent preferably comprises an imaging unit6in the tip portion5. The imaging unit6is a part that allows visual recognition when imaging is performed from the outside after the stent is placed inside the body. An example of the imaging unit6is a marker based on barium sulfate. Due to the presence of the imaging unit6, the position of the stent and the state of occlusion caused by granulation can be grasped. For example, when the tip portion5is covered with granulation, the marker becomes less clear than when it is not covered with granulation. This allows the doctor to recognize that it is time to replace this stent. The imaging unit6may be the whole or a part of the tip portion5.

The stent preferably has one or more external stoppers7on the outer periphery of the body part3. An example of the external stopper is a ring provided on the outer periphery of the body part3. There may be one ring or multiple rings. The width of the ring may be adjusted as appropriate depending on the shape of the stent. The external stopper is preferably larger than the diameter of the body part (when having a circular outer periphery) and smaller than the diameter (maximum diameter) of the tip portion5. The width of the external stopper is, for example, 0.01 mm or more and 5 mm or less, and may be 0.1 mm or more and 2 mm or less. The presence of such an external stopper prevents the displacement of the placed stent. Of course, the stopper is an optional element, and may not be present.

The stent preferably has a backflow prevention mechanism9on the inner periphery of the body part3. The presence of the backflow prevention mechanism9makes it possible to prevent backflow of liquid in the stent. As an example of the backflow prevention mechanism9, semicircular parts with hollow insides are alternately present. InFIG.1, the backflow prevention mechanism9at the tip is in contact with the inner surface of the body part in the back, and the backflow prevention mechanism9at the bottom is in contact with the inner surface of the body part in the front. Of course, the backflow prevention mechanism9is an optional element, and may not be present. When the inside of this element is removed, it is easier to place the stent using a guide25, described later. The width of the backflow prevention mechanism9may be adjusted as appropriate depending on the size of the stent. The width of the backflow prevention mechanism9is, for example, 0.01 mm or more and 5 mm or less, and may be 0.1 mm or more and 2 mm or less.

FIG.3is a conceptual diagram showing an example of the body part and tip part of the stent. As shown inFIG.3, the stent preferably further has a lower portion15located at the bottom of the body part3. The presence of the lower portion15allows, for example, a nasolacrimal duct stent to prevent lacrimal reflux and reocclusion. The lower portion may have the same structure as the upper tip portion, but may have a different structure.

In the stent, the connecting part19that connects the body part3to the tip portion5is preferably a shape memory part.

As shown inFIG.1, the stent has an extension part21extending from the lower tip portion5, and the extension part21may have, at its tip, a tip part23that forms a curved surface and that is harder than the body part3. The tip part23may have a plurality of holes or may be sealed. The sealed tip part23functions as a stopper. The tip part23and all or part of the extension part21may be cut and removed after the stent is placed.

A stent having such a structure can be easily placed.

FIG.4is a conceptual diagram showing an example of the body part of the stent. As shown inFIG.4, the stent may have multiple stages of tip portions5(portions that become wider toward the tip). Particularly in this case, the tip portions5may also be referred to as wide portions or wing portions.

FIG.5is a conceptual diagram showing an example of the kit of the present invention. The stent guide25is inserted into the body part3and guides the stent to the target location. The stent guide25has a blade27on the inner surface of its tip. The stent guide25may be a suction tube.

FIG.6is a conceptual diagram showing an example of the tip part of a suction tube.FIG.6Ashows a cross-sectional view of the tip part of the suction tube, andFIG.6Bshows an X-X cross-sectional view ofFIG.6A. The suction tube is a medical suction tube having a tubular suction tube body part33and a connecting part that connects the suction tube body part33to a suction device. Suction tubes have suction tube body parts in various shapes, such as a tubular linear shape, a cylindrical shape with a part whose diameter decreases toward the tip, and a tubular shape with a bent part in the middle. The diameter φ of the tubular suction tube body part33is, for example, 0.5 mm or more and 1 cm or less, and may be 0.5 mm or more and 5 mm or less, or 1 mm or more and 3 mm or less. Since the present invention is preferably used in a minute region where it is difficult to open and close medical scissors, the diameter φ may be 0.5 mm or more and 2 mm or less. As shown inFIG.6, a blade39for resecting tissue is provided inside the tip region of the suction tube body part33. All or part of the edge (peak) of the blade39is preferably connected to the inner wall of the suction tube body part33of the suction tube. It is preferable that the part (cutting blade part) that cuts the target site, such as tissue, faces toward a central axis of the suction tube inside the suction tube. The cutting blade part may extend in the direction perpendicular to the central axis of the suction tube body part33, or may extend at an angle upward or downward.

The pressure of the suction tube becomes negative upon suction from the suction device. Therefore, as shown inFIG.6A, the blade39preferably has a taper (inclination) such that the width of the blade increases toward the tip (the upper part of the drawing) (the cutting blade part extends at an angle upward with respect to the central axis of the suction tube body part33). The suction force can be increased by the possession of such a blade. On the other hand, as shown inFIG.6B, when the blade has a hollow shape (a shape in which there is no blade around the central axis), there is a portion above the blade39where the suction from the suction device is weakened. If there is microtissue that is not desired to be sucked, the microtissue can be positioned above the blade39, thereby protecting the tissue while sucking body fluids, which is preferable. From such a viewpoint, the blade length (blade width: distance from the inner wall of the suction tube to the blade edge) is, when the inner diameter of the suction tube is regarded as φ, is preferably 1/20 or more and ⅓ or less of φ, and may be 1/10 or more and ¼ or less, or 1/10 or more and ⅕ or less. Since the suction tube is very small, the thickness of the blade may be adjusted accordingly. For example, the thickness of the blade may be 10 μm or more and 1 mm or less, 50 μm or more and 0.5 mm or less, or 0.1 mm or more and 0.5 mm or less. The blade39may be present at the tip of the suction tube, or as shown inFIG.6A, below the tip to secure the top of the blade and avoid blade loss. The blade ofFIG.6Bhas a hollow circular shape. Alternatively, the blade may be chord-shaped, or may not be a perfect circle but may be in a state of being partially present, such as a distorted circle or a tooth mark.

FIG.7is a conceptual diagram showing an example of a cutting blade part extending at an angle from the direction perpendicular to the central axis of the suction tube body part.FIG.7Ashows an example of a cutting blade part extending at an angle upward from the direction perpendicular to the central axis of the suction tube body part, andFIG.7Bshows an example of a cutting blade part extending at an angle downward from the direction perpendicular to the central axis of the suction tube body part. InFIG.6, the blade39extends substantially perpendicular from the inner wall of the suction tube body part33, while inFIG.7, the blade is inclined. InFIG.7A, θ indicates the taper angle of the cutting blade part, and θ is, for example, 1 degree or more and 45 degrees or less, and may be 5 degrees or more and 30 degrees or less, or 5 degrees or more and 20 degrees or less.

FIG.8is a conceptual diagram showing an example of a suction tube having a blade that is a hollow blade present inside the suction tube body part at an angle with respect to the central axis of the suction tube body part, and having an edge in contact with the inside of the suction tube body part. In this example, the tip of the suction tube is cut diagonally like an injection needle, and a blade39is present along the cut tip. Alternatively, the tip part may be tubular. The blade39is a hollow blade that is present inside the suction tube body part at an angle with respect to the central axis41of the suction tube body part, and that has an edge in contact with the inside of the suction tube body part, whereby a small object can be easily resected. When the tip region of the suction tube body part has a shape inclined with respect to the central axis of the suction tube body part along the blade, the suction tube itself can be used like an injection needle, and the suction tube body part can be used to resect the object or to continuously suck body fluids, such as blood, while being inserted into the tissue. The inclination may have any angle. Assuming that an angle of 0 degrees is perpendicular to the central axis11, the inclination is, for example, 1 degree or more and 70 degrees or less, and may be 5 degrees or more and 45 degrees or less, 10 degrees or more and 30 degrees or less, or 10 degrees or more and 50 degrees or less.

The edge of the blade is preferably in contact with the inside of the suction tube body part. The number of blades may be one, or there may be a plurality of blade parts.FIG.9is a conceptual diagram showing an example of a suction tube having a plurality of blade parts. In the example shown inFIG.9, the blade has a plurality of blade parts with edges in contact with the inside of the suction tube body part, and the plurality of blade parts are inclined with respect to the central axis of the suction tube body part. Having such a shape makes it possible to easily resect the target tissue and the like.FIG.9Ais a conceptual diagram of the suction tube being divided in half.FIG.9Bis a view of the suction tube ofFIG.9Aviewed from above. In the example ofFIG.9, four blade parts are provided every 90 degrees. The blade edges are present in parts facing toward the central axis, and the object, such as tissue, inserted into the suction tube can be resected. When the suction tube has a plurality of blades39, the plurality of blades39may be inclined in the same direction (when the suction tube body part33is developed, the orientations of the blades39are approximately parallel to each other, like /,/,/,/), or the adjacent blades39may be inclined in opposite directions (when the suction tube body part33is developed, the orientations of the blades39are like /,\,/,\).

FIG.10is a conceptual diagram showing an example of a plurality of (three) inclined cutting blade parts extending at an angle from the direction perpendicular to the central axis of the suction tube body part.FIG.10Ashows a conceptual diagram of the suction tube viewed from above,FIG.10Bshows an X-X cross-sectional view ofFIG.10A, andFIG.10Cshows a Y-Y cross-sectional view ofFIG.10A. When the suction tube body part of the suction tube is rotated, the target tissue can be easily resected by the cutting blade parts of the blades.

FIG.11is a conceptual diagram showing an example of a suction tube comprising a rotation mechanism for rotating the suction tube body part. The rotation mechanism is an optional element; however, the presence of the rotation mechanism has an advantageous effect as explained below. For example, the rotation mechanism43is hollow, and does not prevent the suction of liquid or objects by the suction tube. This suction tube may have a hole to relieve pressure. In an example of the rotation mechanism43, when the rotation mechanism43is rotated with a finger or a hand using a rotation drive mechanism, such as a ball bearing, the suction tube body part33can be driven to rotate with respect to the connecting part, along with the rotation of the rotation mechanism. When the rotation mechanism43is moved with a finger, the blade rotates in accordance with the rotation of the suction tube body part of the suction tube; thus, the target tissue can be easily resected during the operation. Further, even if the suction of the suction tube is reduced during the operation, the rotation mechanism43can be rotated to thereby give vibration to the suction tube body part and prevent clogging, which also contributes to the efficiency of the operation. In addition, a small motor or actuator may be used to drive the suction tube body part33to rotate with respect to the connecting part37. The rotation mechanism43is connected to a power supply, not shown, and when the practitioner turns on the power (to start the rotation operation), the rotation mechanism43is driven such that the suction tube body part33is rotated by electric power. In this way, the target tissue etc. can be effectively resected.

A preferred example of the use of the suction tube is a tissue collection device comprising the suction tube, and a solution tank that is connected to the suction tube body part33and that contains a sucked object. The solution tank may be connected to a hose or the like connected to the connecting part. For example, liquid and solid are centrifuged because of their different weights; thus, the liquid is sucked into the suction device, and the solid is mainly collected in the solution tank. Since the solution tank contains, for example, a tissue preservation solution, the collected tissue etc. can be analyzed.

Stents for various specific applications will be described below. Conjunctival nasal cavity stent and conjunctival lacrimal stent

The total length of a conjunctival nasal cavity stent and conjunctival lacrimal stent is, for example, 0.5 cm or more and 3.5 cm or less. The total length may be 1 cm or more and 3 cm or less. The conjunctival nasal cavity stent and conjunctival lacrimal stent preferably have a mesh-like body part3. The body part3may be formed by using a memory alloy, or a tip part23may not be provided.

Nasolacrimal Duct Stent

A nasolacrimal duct stent is one of the applications in which the effect of the stent of the present invention can be most exerted. The total length of the nasolacrimal duct stent is, for example, 1 cm or more and 6 cm or less, and may be 2 cm or more and 5 cm or less. A tip part23may not be provided.

Monro Foramen Stent and Cerebral Aqueduct Stent

The total length of a Monro foramen stent and cerebral aqueduct stent is, for example, 1.5 cm or more and 20 cm or less. The Monro foramen stent and cerebral aqueduct stent are preferably not provided with a tip part23.

Eustachian Tube Stent

The total length of a eustachian tube stent is, for example, 2 cm or more and 4.5 cm or less. The eustachian tube stent preferably has a mesh-like body part3. The body part3may be formed by using a memory alloy, or a tip part23may not be provided.

Bile Duct Stent

The total length of a bile duct stent is, for example, 2 cm or more and 15 cm or less. The bile duct stent preferably has a mesh-like body part3. The body part3may be formed by using a memory alloy, or a tip part23may not be provided.

Pancreatic Duct Stent

The total length of a pancreatic duct stent is, for example, 10 cm or more and 15 cm or less. The pancreatic duct stent preferably has a mesh-like body part3. The body part3may be formed by using a memory alloy, or a tip part23may not be provided.

Anal Stent

The total length of an anal stent is, for example, 15 cm or more and 30 cm or less. The anal stent preferably has a mesh-like body part3. The body part3may be formed by using a memory alloy, or a tip part23may not be provided.

Ureteral Stent

The total length of a ureteral stent is, for example, 15 cm or more and 30 cm or less. The ureteral stent preferably has a mesh-like body part3. The body part3may be formed by using a memory alloy, or a tip part23may not be provided.

Fallopian Tube Stent

The total length of a fallopian tube stent is, for example, 8 cm or more and 18 cm or less. The fallopian tube stent preferably has a mesh-like body part3. The body part3may be formed by using a memory alloy, or a tip part23may not be provided.

INDUSTRIAL APPLICABILITY

The present invention can be used in the field of medical devices.

REFERENCE SIGNS LIST

3. Body part5. Tip portion6. Imaging unit7. External stopper9. Backflow prevention mechanism15. Lower portion19. Connecting part21. Extension part23. Tip part