Medical needle

Abstract

Provided is a medical needle that has fairly large piercing resistance and allows puncture of a target site to be easily controlled. Provided is a medical needle 10 having a needle body 20 that extends along a central axis C and is capable of puncturing a biological tissue. The needle body 20 has a cutting edge tip portion 33 having a polygonal cross-sectional shape orthogonal to the central axis C in which flat surface portions 40 are adjacent to each other in the circumferential direction with ridge lines 41 between and a most distal end portion 34 distal to the cutting edge tip portion 33. The most distal end portion 34 branches from the tips of the ridge lines 41 of the cutting edge tip portion 33 toward the tip side and has a plurality of curved most distal end ridge lines 42 that are connected to the tips of the ridge lines 41 adjacent in the circumferential direction of the cutting edge tip portion 33.

Description

medical needle

[0001] The present invention relates to a medical needle that can be inserted into biological tissue.

[0002] Medical needles are used for biopsies to collect biological tissue samples, administering drugs to living organisms, suturing tissue, and other purposes. Because needles have sharp tips, there is a risk of unintentional puncture. For this reason, as disclosed in Patent Literature 1, for example, medical needles are known that have a tip shape designed to prevent injury to the surgeon even if the surgeon touches the needle tip, while also reducing the resistance to puncture when the needle is inserted into the patient.

[0003] Japanese Patent Application Publication No. 6-296790

[0004] Medical needles used in biopsies have a large outer diameter for collecting samples, and when using them to administer medication, the medication is likely to leak out. If the outer diameter of a medical needle is reduced, the needle's penetration resistance decreases, making it difficult for the surgeon to sense its progress through biological tissue at the handle, making it difficult to puncture the target location. Furthermore, if the needle's penetration resistance is low, when inserting the medical needle into organ tissue, there is a risk of unintended puncture of a blood vessel due to factors such as heartbeat, patient movement, or organ activity.

[0005] The present invention has been made to solve the above-mentioned problems, and has an object to provide a medical needle that has a certain degree of resistance to puncture and that allows easy control of puncturing into the target site.

[0006] The medical needle (1) according to the present invention that achieves the above-mentioned object is a medical needle having a needle body that extends along a central axis and can puncture biological tissue, wherein the needle body has a cutting edge tip portion whose cross-sectional shape perpendicular to the central axis is polygonal as a result of flat portions being adjacent to each other in the circumferential direction across ridge lines, and a most distal portion located distally of the cutting edge tip portion, wherein the most distal portion has a plurality of curved most distal ridge lines that branch from the tips of the ridge lines of the cutting edge tip portion toward the tip side and connect to the tips of the ridge lines that are adjacent to the cutting edge tip in the circumferential direction.

[0007] The medical needle (1) configured as described above has ridges and a tip ridge where the surfaces are adjacent to each other, but the tip of the needle body is not sharp, so that it is possible to puncture biological tissue while increasing the puncture resistance of the tip of the cutting edge during puncture, thereby preventing unintentional puncture.

[0008] (2) In the medical needle of (1) above, the needle body may have a needle tube portion having a lumen through which fluid can flow, a needle tube connecting portion having a circular cross section perpendicular to the central axis and extending from the needle tube portion toward the tip, and a cutting edge base end portion located between the needle tube connecting portion and the cutting edge tip end and from which the flat portion extends. As a result, the cutting edge base end of the medical needle has a flat portion but a shape without corners, which prevents the needle body's penetration resistance from becoming too low, and by smoothly changing the cross-sectional shape of the needle body along the central axis, it is possible to prevent a sudden change in penetration resistance during puncture due to friction between the cutting edge base end and biological tissue.

[0009] (3) In the medical needle of (2) above, the cutting edge base end may have a cross-sectional shape perpendicular to the central axis that is a rounded polygon. This allows the medical needle to have rounded portions at the cutting edge base end where the flat portions are adjacent to each other, preventing the penetration resistance of the needle body from becoming too low and preventing a sudden change in penetration resistance during puncture due to friction between the cutting edge base end and biological tissue caused by the rounding.

[0010] (4) In the medical needle of any of (1) to (3) above, the most distal end portion may have a curved surface surrounded by the most distal ridge line, whereby the medical needle has a curved distal end surface of the needle body, thereby increasing the puncture resistance of the cutting edge tip when puncturing.

[0011] (5) In any of the medical needles (1) to (4) above, the cutting edge tip may have a triangular or rectangular cross-sectional shape. This allows the medical needle to advance smoothly in a straight line during puncture by incising the biological tissue with the ridge line, and the flat surfaces are adjacent to each other across the ridge line at an angle of 90° or less, making it difficult for the biological tissue to be spread apart during puncture, making it easier for the puncture wound to close when the needle body is removed, and improving hemostasis.

[0012] (6) The medical needle of any of (1) to (5) above may have a sheath that covers the outer periphery of the needle body and allows the needle body to move along the central axis, and a valve that contacts the needle body may be provided at the tip of the sheath. This prevents the needle body from unintentionally exposing from the sheath, thereby preventing unintentional puncture. Furthermore, because the tip of the sheath is blocked by the valve through which the needle body penetrates, the medical needle prevents substances from biological tissue from flowing back into the sheath from the tip side of the sheath.

[0013] (7) In the medical needle of (6) above, the valve body may be radially expandable and contractible and have a central opening, and the cross-sectional shape of the opening in the valve body perpendicular to the central axis may be the same as the cross-sectional shape of the cutting edge tip perpendicular to the central axis. This improves the adhesion between the valve body and the needle body, and further prevents substances from biological tissue from flowing back into the sheath from the distal end of the sheath.

[0014] (8) In the medical needle of (6) or (7) above, the valve may be configured to deform so as to protrude from the tip of the sheath when the needle body protrudes toward the tip side of the sheath. This allows the medical needle to have a high degree of adhesion between the valve and the needle body, while smoothly changing the resistance when the needle body passes the valve and is exposed toward the tip side, making the puncture operation comfortable.

[0015] (9) In the medical needle of any of (6) to (8) above, the valve body may be held on the inner surface of an outer sheath member connected to the sheath. This allows the outer sheath member to suppress radial expansion of the valve body, thereby improving the sealing ability of the needle body by the valve body.

[0016] 11 is a front view of a puncture device having a medical needle of this embodiment. 12 is a perspective view of the tip of the medical needle. 13 is a front view of the tip of the medical needle. 14 is a cross-sectional view of FIG. 3, where (a) is an A-A cross-sectional view, (b) is a B-B cross-sectional view, and (c) is a CC cross-sectional view. 15 is an enlarged view of the tip of the medical needle as viewed from the tip side. 16 is a front view of the most distal end of the medical needle. 17 is a graph showing the relationship between the distance and the pushing force when the medical needle is punctured. 18 is a perspective view of the tip when the medical needle is housed in the inner sheath. 19 is a front view of the medical needle and the distal end of the inner sheath, where (a) shows the medical needle housed in the inner sheath and (b) shows the medical needle exposed from the inner sheath to the tip side. 19 is an enlarged view of the inner sheath excluding the tip member as viewed from the tip side. 19 is a front view of the most distal end of the medical needle when the most distal surface of the medical needle is an ellipsoidal sphere. 19 is a perspective view of the tip of the medical needle of FIG. 11.

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the dimensional proportions in the drawings may be exaggerated for convenience of explanation and may differ from the actual proportions. In addition, in this specification, a device has an axis, and the side of the device that is inserted into biological tissue will be referred to as the "distal side" in the axial direction, and the side that is operated will be referred to as the "proximal side" in the axial direction.

[0018] The medical needle 10 of this embodiment is used to puncture biological tissue in a puncture device 100. The puncture device 100 is inserted into the forceps port of an endoscope (not shown), and the tip is delivered to a target lesion such as cancer, and is used to perform treatment such as a biopsy or the administration of a drug.

[0019] As shown in Figure 1, the puncture device 100 holds a medical needle 10 consisting of a needle body 20 extending from a proximal portion 110 toward the tip side and an inner sheath 25 as a sheath. The inner sheath 25 covers the outer periphery of the needle body 20, and in Figure 1, the entire needle body 20 up to the tip is housed inside the inner sheath 25. The needle body 20 is movable along the central axis relative to the inner sheath 25. The puncture device 100 further has an outer sheath 26 that houses the inner sheath 25 inside. A portion of the tip side of the inner sheath 25 is housed inside the outer sheath 26.

[0020] The proximal portion 110 includes an endoscope connecting portion 111 fixed to the forceps port of the endoscope, an extension portion 111a extending from the endoscope connecting portion 111 toward the proximal end, a distal side portion 112 positioned on the proximal side of the extension portion 111a so as to cover the extension portion 111a and movable in the axial direction relative to the endoscope connecting portion 111, an intermediate portion 113 positioned on the proximal side of the distal side portion 112 so as to cover the distal side portion 112 and movable in the axial direction relative to the distal side portion 112, and a handle portion 114 positioned on the proximal side of the intermediate portion 113 so as to cover the intermediate portion 113 and movable in the axial direction relative to the intermediate portion 113. A first fixing screw 112a is provided on the outer surface of the extension portion 111a to fix the endoscope connecting portion 111 to the extension portion 111a so as to prevent it from moving. The first fixing screw 112a is connected to and fixed to the distal side portion 112. The distal side portion 112 has a first stopper portion 112b that protrudes like a flange near the base end of the first fixing screw 112a, and when the second fixing screw 113a moves toward the distal side, the first stopper portion 112b prevents the second fixing screw 113a from moving toward the distal side. The outer surface of the distal side portion 112 is provided with a second fixing screw 113a that fixes the intermediate portion 113 to prevent movement relative to the distal side portion 112. The outer surface of the intermediate portion 113 is provided with a third fixing screw 114a that fixes the handle portion 114 to prevent movement relative to the intermediate portion 113. The intermediate portion 113 has a second stopper portion 113b that protrudes like a flange near the base end of the second fixing screw 113a, and when the third fixing screw 114a moves toward the distal side, the second stopper portion 113b prevents the third fixing screw 114a from moving toward the distal side.

[0021] The proximal end of the inner sheath 25 is fixed near the proximal end of the intermediate section 113. Therefore, by moving the intermediate section 113 in the axial direction relative to the distal section 112, the inner sheath 25 can be moved in the axial direction relative to the endoscope.

[0022] Because the needle body 20 is fixed to the handle portion 114, the needle body 20 can be moved axially relative to the inner sheath 25 by moving the handle portion 114 axially relative to the intermediate portion 113. The base end of the outer sheath 26 is fixed near the base end of the distal end portion 112. Therefore, by moving the intermediate portion 113 and the handle portion 114 axially relative to the distal end portion 112, the axial positions of the needle body 20 and the inner sheath 25 relative to the outer sheath 26 can be adjusted.

[0023] As shown in Figures 2 and 3, the needle body 20 extends along the central axis C, and includes a needle tube portion 30 having a lumen 30a through which fluid can flow, a solid needle tube connecting portion 31 located at the distal end of the needle tube portion 30, a cutting edge base end 32 located at the distal end of the needle tube connecting portion 31, a cutting edge distal portion 33 located at the distal end of the cutting edge base end 32, and a distal end portion 34 located at the distal end of the cutting edge distal portion 33.

[0024] The needle tube connecting portion 31 has a fluid opening 30b that connects the lumen 30a to the outside. The distal end of the fluid opening 30b and the distal end of the lumen 30a preferably coincide along the central axis C. This configuration facilitates the outflow of fluid from the lumen 30a to the outside through the fluid opening 30b. Furthermore, the provision of the fluid opening 30b in the needle tube connecting portion 31 facilitates the flow of fluid into the biological tissue incised by the blade surface. As shown in FIG. 4( c), the needle tube connecting portion 31 has a circular cross section perpendicular to the central axis C. From the base end 32 of the cutting edge to the distal end 33 of the cutting edge, multiple flat surfaces 40 (four in this embodiment) are formed in the circumferential direction. Each flat surface 40 is a region surrounded by a ridge line 41, a distal ridge line 42 (described later), and a cutting surface edge 43. At the distal end 33 of the cutting edge, the flat surfaces 40 are adjacent to each other in the circumferential direction, sandwiching the ridge line 41 between them. Therefore, as shown in FIG. 4( a), the cutting edge tip 33 has a rectangular cross-section perpendicular to the central axis C. The ridge lines 41, which form the corners of the rectangle, are formed by two adjacent flat surfaces 40 forming a 90° angle. Therefore, the ridge lines 41 can function as a blade surface to incise biological tissue. In this embodiment, the cutting edge tip 33 has a rectangular cross-section perpendicular to the central axis C, but it may also have a triangular or polygonal shape with pentagons or more sides. Because the cutting edge tip 33 has a triangular or rectangular cross-section perpendicular to the central axis C, the ridge lines 41 incise the biological tissue, improving linearity during puncture. Furthermore, because the flat surfaces 40 are adjacent to each other across the ridge line 41 at an angle of 90° or less, the biological tissue is less likely to be pushed apart during puncture, and the puncture wound is more likely to close when the needle body 20 is removed. This also improves hemostasis.

[0025] The cutting edge base end 32 has a cross-sectional shape perpendicular to the central axis C that connects the circular needle tube connecting portion 31 and the polygonal cutting edge distal end 33, and as shown in Figure 4(b) , the cross-sectional shape perpendicular to the central axis C is a rounded polygon. Because the cutting edge base end 32 has a flat portion 40 but no corners, it is possible to prevent the penetration resistance of the needle body 20 from becoming too low, while also preventing a sudden change in penetration resistance during puncture due to friction between the cutting edge base end 32 and biological tissue by smoothly changing the cross-sectional shape of the needle body 20 along the central axis C.

[0026] The most distal end portion 34 has a most distal ridge 42 that branches from the tip of the ridge 41 of the cutting edge distal end 33 toward the distal end and connects to the tip of the ridge 41 adjacent to it in the circumferential direction of the cutting edge distal end 33. The most distal ridge 42 is curved and convex toward the distal end. The most distal end portion 34 has a curved surface 34a that is convex toward the distal end and is surrounded by four most distal ridges 42. The curved surface 34a is a quadratic curve. The most distal ridge 42 is formed so that the curved surface 34a and the flat portion 40 are adjacent to each other, which maximizes the penetration resistance of the cutting edge distal end 33 and prevents the penetration resistance of the needle body 20 from becoming too low. Furthermore, the position where the most distal ridge 42 branches off from the ridge 41 is the intersection (corner) of two most distal ridges 42 and one ridge 41, and therefore serves as the starting point for the ridge 41 to incise biological tissue, applying a force to cut through the biological tissue.

[0027] As shown in FIG. 5, the radius of the needle tube connection portion 31 is r1, and the length from the central axis C to the position where the most distal ridge line 42 branches off from the ridge line 41 is r2. Also, as shown in FIG. 6, the intersection point between the central axis C and a plane P1 that is perpendicular to the central axis C and includes the position where the most distal ridge line 42 branches off from the ridge line 41 is α, the distance between the intersection point α and an imaginary plane P2 extending from the curved surface 34a is D, and the distance between the intersection point α and the most distal position of the curved surface 34a is d. Also, the angle that the flat portion 40 of the cutting edge tip 33 makes with the direction of the central axis C is ∠A. In this case, r1 > r2, and the position where the ridge line 41 branches off to the most distal ridge line 42 is determined by the ratio of r1 to r2. Furthermore, since D ≥ r2, it is determined that the distal surface of the most distal portion 34 is a quadratic curved surface 34a that is convex toward the distal end. The intersection of the virtual plane V extending from the cutting edge tip 33 and the quadric surface 34 a is at the same position in the direction along the central axis C as the most distal end position of the most distal ridge line 42 .

[0028] For example, the dimensions and angles can be A = 3°, r1 = 0.4 mm, r2 = 0.3 mm, D > r2, and d = 0.1 mm. When D = d, the curved surface 34a, which forms the tip surface of the most distal end 34, is spherical, and when D ≠ d, it is curved. Therefore, the resistance to penetration into biological tissue is greater than that of a needle with a sharp tip. Although the curved surface 34a is not sharp, the needle body 20 can be punctured into biological tissue because of its thin diameter. In Figure 7, the dashed dotted line shows the relationship between puncture distance and pushing force when a needle having a tip shape that is an imaginary plane V extending from the cutting edge tip 33 shown in Figure 6 is punctured into biological tissue. The solid line shows the relationship between puncture distance and pushing force when the needle body 20 of this embodiment is punctured into biological tissue. The two-dot chain line shows the relationship between puncture distance and pushing force when a needle having a shape in which the distal-most ridge 42 is eliminated from the needle body 20 of this embodiment and in which the curved surface 34a and the flat surface 40 are connected by a continuous, rounded curved surface is inserted into biological tissue. The peak pushing force f1 of the needle body 20 of this embodiment is greater than the peak pushing force f3 of a needle with a sharp tip. Furthermore, the peak pushing force f1 is greater than the peak pushing force f2 of a needle having a shape in which the curved surface 34a and the flat surface 40 are connected by a continuous, rounded curved surface. Furthermore, the peak pushing force f2 of a needle having a shape in which the curved surface 34a and the flat surface 40 are connected by a continuous, rounded curved surface is greater than the peak pushing force f3 of a needle with a sharp tip. In other words, the needle body 20 of this embodiment requires a greater puncture force than a needle with a sharp tip, thereby preventing unintended puncture. Furthermore, in the needle body 20 of this embodiment, the distance L2 over which the pushing force decreases from the position where the pushing force peaks is shorter than the distance L1 over which the pushing force decreases from the position where the pushing force peaks in a needle that does not have the distal edge 42. In other words, the pushing force of the needle body 20 decreases rapidly once the pushing force passes the position where the pushing force peaks. Therefore, the needle body 20 with the distal edge 42 can clearly convey the feeling of puncture to the surgeon, enabling reliable puncture.

[0029] 8 , the inner sheath 25 has a cylindrical inner sheath body 50 and an outer mantle member 51 connected to the distal end of the cylindrical inner sheath body 50. The outer mantle member 51 has a distal opening 54 at its tip end, through which the needle body 20 passes. The cylindrical inner sheath body 50 is fixed to the proximal end side of the intermediate section 113, and the length of the needle body 20 protruding from the inner sheath 25 can be determined by adjusting the third fixing screw 114 a and moving the handle section 114 in the axial direction relative to the intermediate section 113.

[0030] As shown in Figure 9(a), the mantle member 51 holds a valve body 52 on its inner surface, which contacts the needle body 20 in the circumferential direction. The valve body 52 can be made of a flexible material with elasticity, such as silicone or elastomer. Because the valve body 52 is provided at the tip of the inner sheath 25, a certain amount of force is required for the needle body 20 to move toward the tip beyond the valve body 52. ​​This prevents the needle body 20 from being exposed at the tip side of the inner sheath 25 and causing unintended puncture.

[0031] The valve body 52 is disposed on the inner surface of the mantle member 51 proximal to the distal opening 54, and a space (a space formed by the inner surface of the valve body 52) is formed inside the mantle member 51 inside the valve body 52. ​​As shown in FIG. 9( b), the valve body 52 flexibly deforms in accordance with the movement of the needle body 20, thereby increasing the adhesion between the valve body 52 and the needle body 20 and smoothly changing the resistance when the needle body 20 passes the valve body 52 and is exposed to the distal side, thereby making the puncturing operation comfortable. Furthermore, when the needle body 20 is retracted into the inner sheath 25 after puncturing, tumor-derived substances such as blood adhering to the needle body 20 are collected in the space inside the valve body 52, preventing these substances from leaking and seeding toward the distal side of the puncturing device 100.

[0032] The mantle member 51 that holds the valve body 52 has a marker portion 51a. The marker portion 51a has a fine uneven shape on its surface so that it can be visualized with ultrasound. The marker portion 51a may also be made of a material that has radiopaque properties so that it can be visualized with X-rays.

[0033] 10 , the valve body 52 held by the outer mantle member 51 has an opening 52a in the center. The opening 52a is formed so that its cross-sectional shape perpendicular to the central axis C is the same as the cross-sectional shape perpendicular to the central axis C of the cutting edge tip 33. This increases the adhesion between the valve body 52 and the cutting edge tip 33 when the cutting edge tip 33, which has a diameter that decreases toward the tip, passes through the valve body 52, and prevents blood and the like from flowing back into the inner sheath 25 from the tip side of the inner sheath 25.

[0034] The following describes how to use the puncture device 100 including the medical needle 10. The target puncture site is identified in advance by diagnostic imaging. Once the target site has been identified, an endoscope (not shown) is inserted into the patient's body. The puncture device 100 is inserted into the forceps port of the endoscope with the tip of the needle body 20 protruding from the tip of the inner sheath 25, and the outer sheath 26 (the tip of the needle body 20 is located proximal to the tip of the outer sheath 26) with the needle body 20 and inner sheath 25 inserted therein is inserted. The outer sheath 26 is then advanced until the tip of the outer sheath 26 reaches the vicinity of the target site. Once the outer sheath 26 has been inserted to the target position, the puncture device 100 is secured to the endoscope by the endoscope connector 111.

[0035] The surgeon determines the puncture length based on the condition of the target site identified by diagnostic imaging and adjusts the position of the second fixing screw 113a so that the handle portion 114 and the intermediate portion 113 can be moved by the determined puncture length. The surgeon then pushes the handle portion 114 and the intermediate portion 113 toward the distal end, causing the needle body 20 and the inner sheath 25 to protrude from the distal end of the outer sheath 26 and puncture the needle body 20 and the inner sheath 25 into the target site. As a result, the inner sheath 25 and the needle body 20 exposed from the distal end of the outer sheath 26 puncture biological tissue such as the pancreas. Next, the surgeon adjusts the position of the third fixing screw 114a so that the handle portion 114 can be moved. The surgeon then pushes the handle portion 114 toward the distal end, increasing the length of the needle body 20 protruding from the distal end of the inner sheath 25. As a result, the tip of the needle body 20 exposed from the tip of the inner sheath 25 crosses the boundary (interface) between target tissue containing tumor cells, etc., present inside the pancreas, etc., and normal tissue, and punctures the target tissue (target site). The surgeon then operates the syringe to administer a drug through the needle body 20. After administering the drug, the surgeon operates the handle portion 114 to retract the entire needle body 20, including the tip of the needle body 20, into the inner sheath 25. After the entire needle body 20 has been retracted into the inner sheath 25, the surgeon operates the intermediate portion 113 to retract the needle body 20 and inner sheath 25 into the outer sheath 26, and then removes the puncture device 100 from the endoscope. The needle body 20 has a curved tip surface 34a, which provides high puncture resistance, thereby preventing unintentional puncture of a blood vessel, etc., at the target site. On the other hand, the needle body 20 has multiple ridges 41 at the cutting edge tip 33, so it can proceed with puncturing while cutting open the biological tissue. In addition, the needle body 20 has a leading edge 42 at the cutting edge tip 33, so the pushing force decreases rapidly once the point at which the pushing force reaches its peak is exceeded, allowing the surgeon to clearly feel the puncture.

[0036] Once the needle body 20 has been inserted, a certain treatment is performed. For example, a biopsy can be performed by applying negative pressure to the lumen 30a of the needle tube portion 30 to draw in a biological tissue sample through the fluid opening 30b. Alternatively, a drug can be supplied to the lumen 30a of the needle tube portion 30 and administered through the fluid opening 30b. Other treatments may also be performed using the punctured needle body 20. When the needle body 20 is used for a biopsy, the biological tissue is pierced with a stylet inserted into the lumen 30a. By inserting the stylet all the way to the tip of the fluid opening 30b, the biological tissue can be prevented from entering the lumen 30a through the fluid opening 30b.

[0037] After performing the treatment, the surgeon operates the handle 110 to store the needle body 20 inside the inner sheath 25. At this time, the valve body 52 prevents blood and other substances from flowing back into the inner sheath 25. After the needle body 20 has been stored in the inner sheath 25, the surgeon removes the puncture device 100 from the endoscope.

[0038] 11 and 12 , the tip 62 of the needle body 60 may have a curved surface 62a that forms the tip surface having an ellipsoidal spherical shape. The cutting edge tip 61 of the needle body 60 has multiple ridges 63 and a tip ridge 64 that branches off from the tip of the ridge 63, with the tip side of the tip ridge 64 forming the tip 62, and the portion surrounded by the tip ridge 64 forming the curved surface 62a that is an ellipsoidal spherical shape. Alternatively, the curved surface of the tip may have another shape, such as an aspherical shape.

[0039] As described above, the medical needle 10 according to the present embodiment (1) is a medical needle 10 having a needle body 20 that extends along a central axis C and can puncture biological tissue, and the needle body 20 has a cutting edge tip 33 in which the flat portions 40 are adjacent to each other in the circumferential direction across a ridge line 41, so that the cross-sectional shape perpendicular to the central axis C is polygonal, and a most distal portion 34 distal to the cutting edge tip 33, and the most distal portion 34 has a plurality of curved most distal ridge lines 42 that branch from the tip of the ridge line 41 of the cutting edge tip 33 toward the distal side and connect to the tip of the ridge line 41 adjacent to the circumferential direction of the cutting edge tip 33. The medical needle 10 configured in this manner has ridge lines 41 and most distal ridge lines 42 whose surfaces are adjacent to each other, and the most distal end of the needle body 20 does not have a sharp shape, so that it can puncture biological tissue while increasing the penetration resistance of the cutting edge tip during puncture, thereby preventing unintended puncture.

[0040] (2) In the medical needle 10 described in (1) above, the needle body 20 may have a needle tube portion 30 having a lumen 30a through which fluid can flow, a needle tube connecting portion 31 having a circular cross section perpendicular to the central axis C and extending from the needle tube portion 30 toward the tip, and a cutting edge base end 32 located between the needle tube connecting portion 31 and the cutting edge distal end 33 and from which a flat portion 40 extends. As a result, the cutting edge base end 32 of the medical needle 10 has a shape without corners while having a flat portion 40, which prevents the penetration resistance of the needle body 20 from becoming too low, and by smoothly changing the cross-sectional shape of the needle body 20 along the central axis C, it is possible to prevent a sudden change in penetration resistance during puncture due to friction between the cutting edge base end 32 and biological tissue.

[0041] (3) In the medical needle 10 described in (2) above, the cutting edge base end 32 may have a rounded polygonal cross section perpendicular to the central axis C. This allows the medical needle 10 to have rounded portions at the cutting edge base end 32 where the flat surfaces 40 are adjacent, preventing the penetration resistance of the needle body 20 from becoming too low and preventing a sudden change in penetration resistance during puncture due to friction between the cutting edge base end 32 and biological tissue caused by the rounding.

[0042] (4) In the medical needle 10 of any of (1) to (3) above, the most distal end portion 34 may have a curved surface 34a surrounded by the most distal end ridge 42. As a result, the medical needle 10 has a curved surface 34a at the tip end of the needle body 20, which increases the puncture resistance of the cutting edge tip portion 33 during puncture.

[0043] (5) In any of the medical needles 10 described above in (1) to (4), the cutting edge tip 33 may have a triangular or rectangular cross-sectional shape. This allows the medical needle 10 to advance smoothly in a straight line during puncture due to the incision of the biological tissue by the ridges 41. Furthermore, because the flat surfaces 40 are adjacent to each other across the ridges 41 at an angle of 90° or less, the biological tissue is less likely to be spread apart during puncture, making it easier for the puncture wound to close when the needle body 20 is removed, and improving hemostasis.

[0044] (6) The medical needle 10 of any of (1) to (5) above may have an inner sheath 25 that covers the outer periphery of the needle body 20 and allows the needle body 20 to move along the central axis C, and the tip of the inner sheath 25 may be provided with a valve body 52 that comes into contact with the needle body 20. This prevents the needle body 20 from being unintentionally exposed from the inner sheath 25, thereby preventing unintentional puncture. Furthermore, because the tip of the inner sheath 25 is blocked by the valve body 52 through which the needle body 20 passes, the medical needle 10 prevents substances from biological tissue from flowing back into the inner sheath 25 from the tip side of the inner sheath 25.

[0045] (7) In the medical needle 10 described in (6) above, the valve body 52 is radially expandable and has an opening 52a in the center, and the cross-sectional shape of the opening 52a of the valve body 52 perpendicular to the central axis C may be the same as the cross-sectional shape of the cutting edge distal end 33 perpendicular to the central axis C. This improves the adhesion between the valve body 52 and the needle body 20 of the medical needle 10, and can better prevent substances from biological tissue from flowing back into the inner sheath 25 from the distal end of the inner sheath 25.

[0046] (8) In the medical needle 10 of (6) or (7) above, the valve body 52 may be configured to deform so as to protrude from the tip of the inner sheath 25 when the needle body 20 protrudes toward the tip side of the inner sheath 25. This allows the medical needle 10 to improve the adhesion between the valve body 52 and the needle body 20, while smoothly changing the resistance when the needle body 20 passes the valve body 52 and becomes exposed toward the tip side, making the puncturing operation feel comfortable.

[0047] (9) In the medical needle 10 of any of (6) to (8) above, the valve body 52 may be held on the inner surface of the outer sheath 51 connected to the inner sheath 25. This allows the outer sheath 51 to suppress radial expansion of the valve body 52 in the medical needle 10, thereby improving the sealing ability of the needle body 20 by the valve body 52.

[0048] The present invention is not limited to the above-described embodiment, and various modifications can be made by those skilled in the art within the technical spirit of the present invention. In the above-described embodiment, the medical needle 10 is connected to the puncture device 100 inserted into an endoscope, but the medical needle 10 may be connected to another type of medical device, such as a syringe or an automatic puncture device, and the type of medical device to be connected is not limited. Furthermore, the treatment performed using the medical needle 10 is not limited.

[0049] This application is based on Japanese Patent Application No. 2024-050158 filed on March 26, 2024, the disclosures of which are incorporated herein by reference in their entirety.

[0050] REFERENCE SIGNS LIST 10 Medical needle 20 Needle body 25 Inner sheath 30 Needle tube portion 30a Lumen 30b Fluid opening 31 Needle tube connecting portion 32 Blade tip base end portion 33 Blade tip distal end portion 34 Most distal portion 34a Curved surface 40 Flat portion 41 Ridge line 42 Most distal ridge line 50 Inner sheath body 51 Outer sheath member 52 Valve body 52a Opening 53 Distal end member 54 Distal end opening 100 Puncture device 110 Proximal portion 114 Handle portion

Claims

1. A medical needle having a needle body that extends along a central axis and can puncture biological tissue, wherein the needle body has a cutting edge tip portion whose cross section perpendicular to the central axis is polygonal as a result of flat portions being adjacent to each other circumferentially across ridge lines, and a most distal portion distal to the cutting edge tip portion, wherein the most distal portion has a plurality of curved most distal ridge lines that branch from the tip of the ridge line of the cutting edge tip portion toward the tip side and connect to the tips of the ridge lines adjacent to the cutting edge tip portion in the circumferential direction.

2. The medical needle according to claim 1, wherein the needle body comprises: a needle tube section having a lumen through which fluid can flow; a needle tube connecting section having a circular cross section perpendicular to the central axis and extending from the needle tube section towards the tip; and a cutting edge base end located between the needle tube connecting section and the cutting edge tip end and from which the flat portion extends.

3. The medical needle according to claim 2, wherein the cross section of the base end of the cutting edge perpendicular to the central axis is a rounded polygon.

4. The medical needle according to any one of claims 1 to 3, wherein the most distal end portion has a curved surface surrounded by the most distal ridgeline.

5. A medical needle according to any one of claims 1 to 3, wherein the cross-sectional shape of the cutting edge tip is triangular or rectangular.

6. A medical needle according to any one of claims 1 to 3, which has a sheath that covers the outer periphery of the needle body and allows the needle body to move along the central axis, and a valve that comes into contact with the needle body is provided at the tip of the sheath.

7. The medical needle according to claim 6, wherein the valve body is radially expandable and has an opening in the center, and the cross-sectional shape of the opening in the valve body perpendicular to the central axis is the same as the cross-sectional shape of the cutting edge tip perpendicular to the central axis.

8. The medical needle according to claim 6, wherein the valve body deforms so as to protrude from the tip of the sheath when the needle body protrudes toward the tip side of the sheath.

9. The medical needle according to claim 6, wherein the valve body is held on the inner surface of an outer sheath member connected to the sheath.

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