JP7769478B2 - medical equipment - Google Patents

Description

The present invention relates to medical puncture needles and medical devices including puncture needles.

In the treatment and diagnosis of various diseases, procedures involve inserting needles into body cavities, blood vessels, organs, etc., for purposes such as injecting medicinal solutions and collecting or draining bodily fluids. As an example of a puncture needle, Patent Document 1 discloses a hollow needle tube with a fluid passage formed inside, a sharpened portion formed at the tip, and an opening for the fluid passage at the sharpened portion. The outer surface of the tip of the needle tube is ground to form a ground portion, and by reducing the outer diameter of the ground portion, puncture resistance is reduced. Furthermore, by reducing the area of the needle inserted into the patient's skin, puncture pain is suppressed.

Patent Document 2 discloses a solid blunt needle for a needle assembly that prevents medical personnel from accidentally touching the tip of a used needle. It also discloses that the solid blunt needle has outer dimensions that are approximately equal to the inner dimensions of the needle cannula that is shaped to accommodate the solid blunt needle.

Patent Document 3 discloses a self-blunting needle device for preventing needle reuse. The self-blunting needle device has a blunting member that includes a long probe, and the blunting member is mounted within the needle member and protrudes axially outward from the needle tip along the needle bore, with a locking means sized and shaped to engage with the blunting member and hold it in its protruding position.

JP 2015-147042 A Japanese Patent Application Laid-Open No. 2000-245838 Special Publication No. 3-501341

Figures 22 and 23 are plan and bottom views, respectively, showing the configuration of a conventional puncture needle, while Figures 24 and 25 are schematic diagrams showing the configuration of the puncture needle. In detail, Figures 22 and 24 show the configuration of the needle's sharp tip 4 in the second embodiment of Patent Document 1. In Figures 22 and 23, the inner periphery 201 of the needle opening is indicated by a dashed line, and the outer periphery 202 is indicated by a dashed line. In Figures 24 and 25, the portion 203 where the blade face angle is acute is indicated by a thick line, the portion 204 where the blade face angle is obtuse is indicated by a line thinner than the thick line, and the portion 205 other than the blade face is indicated by a dashed line. The second embodiment shown in Figure 6 of Patent Document 1 differs from the first embodiment in that an arc-shaped chamfer is formed on the back side of the first blade face 4a of the hollow needle along the outer periphery of the end face of the tip of the needle tube. On the other hand, in the second embodiment, like the first embodiment, the sharpened portion 4 has a first cutting edge 4a and a second cutting edge 4b. As shown in Figures 22 to 25, in the second embodiment, both an acute cutting edge angle 203 and an obtuse cutting edge angle 204 exist on both the inner circumference 201 and outer circumference 202 sides of the needle opening. As a result, in the second embodiment, when the needle is advanced in a direction other than the puncture direction to search for a puncture position within the body (for example, when the tip of the needle is rotated around a point approximately midway along the needle to change its axial direction), the acute cutting edge angle 203 on the outer circumference 202 side of the needle may come into contact with tissue other than the tissue to be punctured, potentially damaging that tissue.

The present invention aims to provide a medical puncture needle and medical device that is less likely to damage tissue other than the target tissue, even when the needle is advanced inside the body in a direction other than the puncture direction.

One embodiment of the medical puncture needle of the present invention that can achieve the above-mentioned object is a medical puncture needle having a needle tube with a tapered portion at its distal portion, wherein in a cross section passing through the central axis of the needle tube when the needle tube is oriented in a direction that maximizes the distance between the central axis and the distal end of the needle tube in the radial direction of the needle tube, a first imaginary line passing through the distal end of the tapered portion on the first side across the central axis and the distal end of the tapered portion on the second side across the central axis extends in a direction different from the direction perpendicular to the central axis, and in a half cross section passing through the central axis of the needle tube and on one side of the central axis, when the maximum outer radius of the tapered portion is T, the lumen radius of the needle tube at the part of the tapered portion with maximum outer radius T is S, and the distance in the radial direction of the needle tube between the distal end of the tapered portion and the central axis is U, the following formula (1) is satisfied, and the gist of the formula (1) is that the following formula (1) is satisfied in all half cross sections at different circumferential positions of the needle tube.
(U-S)<(T-S)/2...(1)
In the medical puncture needle of the present invention, the distal end of the reduced diameter portion is positioned radially inward from the outer periphery of the reduced diameter portion in all half-sections where the circumferential position of the needle tube is different. Therefore, even if the outer surface of the needle tube accidentally comes into contact with tissue other than the target to be punctured when the reduced diameter portion of the needle tube is advanced inside the body in a direction other than the puncture direction to find a suitable position for puncturing with the needle tube, the tissue can be prevented from being damaged.

When viewed from the distal end side of the needle tube, the needle tube has an opening edge formed by the assembly of the distal ends of all of the tapered portions of the cross sections on one side that are located at different circumferential positions of the needle tube, and the needle tube has an annular portion of the tapered portions on the front that is located radially outward of the opening edge of the needle tube, and one or more curved portions may be arranged on the outer surface of the needle tube at the annular portion. Also, the outer surface of the needle tube at the annular portion may not have an edge portion.

In a cross section of the tapered portion passing through the central axis of the needle tube, when the needle tube is oriented in a direction that maximizes the distance between the central axis and the distal end of the needle tube in the radial direction of the needle tube, the angle between the second imaginary line and the central axis may be greater than the angle between the third imaginary line and the central axis. Here, the first side is the side whose distal end is located more distally than the second side, the second imaginary line is a line passing through the distal end and proximal end of the annular portion on the first side, and the third imaginary line is a line passing through the distal end and proximal end of the annular portion on the second side.

The needle tube has, on its outer surface, a first region and a second region located distal to the first region and having a greater surface roughness than the first region. The distal end of the second region may be located distal to the first position, which is located proximal to the proximal end of the tapered portion by the longitudinal length of the needle tube. In this case, the second region may be disposed around the entire circumference of the needle tube. If the needle tube has an annular portion, the second region may be disposed proximal to the annular portion.

The present invention also includes medical devices. One embodiment of the medical device of the present invention comprises a needle tube having a reduced-diameter portion at its distal portion, and a rod-shaped member disposed in the lumen of the needle tube and movable in the longitudinal direction of the needle tube relative to the needle tube, wherein in a cross section passing through the central axis of the needle tube when the needle tube is oriented in a direction that maximizes the distance between the central axis and the distal end of the needle tube in the radial direction of the needle tube, a first imaginary line passing through the distal end of the reduced-diameter portion on a first side across the central axis and the distal end of the reduced-diameter portion on a second side across the central axis extends in a direction different from the direction perpendicular to the central axis, and in a half cross section passing through the central axis of the needle tube and on one side of the central axis, when T is the maximum outer radius of the reduced-diameter portion, S is the lumen radius of the needle tube at the point of maximum outer radius T of the reduced-diameter portion, and U is the distance in the radial direction of the needle tube between the distal end of the reduced-diameter portion and the central axis, the following formula (1) is satisfied, and formula (1) is satisfied in all half cross sections at different circumferential positions of the needle tube.
(U-S)<(T-S)/2...(1)
In the medical device according to the present invention, the distal end of the tapered portion is located radially inward of the outer periphery of the tapered portion in all half cross sections at different circumferential positions of the needle tube, so that even if the outer surface of the needle tube accidentally comes into contact with tissue other than the target tissue to be punctured when the tapered portion of the needle tube is advanced inside the body in a direction other than the puncture direction to find a suitable position for puncturing the needle tube, damage to the tissue can be prevented.Furthermore, in the above medical device, a rod-shaped member is located in the lumen of the needle tube, and by positioning the rod-shaped member so as to overlap the tapered portion of the needle tube, contact of the tapered portion of the needle tube with tissue other than the target tissue can be prevented, thereby further preventing damage to the tissue.

The above medical device may further have a stopper that fixes the longitudinal position of the rod-shaped member relative to the needle tube. When the needle tube has an opening edge formed by the assembly of the distal ends of all of the tapered portions of the cross-sections on one side that are at different circumferential positions on the needle tube when viewed from the front from the distal end side, the rod-shaped member may be fixed by the stopper to a first stop position where the rod-shaped member is located inside the opening edge. Also, when the needle tube has an opening edge, the rod-shaped member may be fixed by the stopper to a second stop position where the rod-shaped member protrudes from the opening edge.

The rod-shaped member may have a third region and a fourth region located distally of the third region on the outer surface of the distal end, the fourth region having a greater surface roughness than the third region. The fourth region may be disposed over the entire circumference of the rod-shaped member.

When the rod-shaped member is moved to the most distal position relative to the needle tube, the proximal end of the fourth region may be located distal to the distal end of the needle tube. Also, the rod-shaped member may be removable from the proximal end of the needle tube.

The medical puncture needle and medical device according to the present invention can prevent damage to tissue even if the outer surface of the needle tube accidentally comes into contact with tissue other than the target tissue when the reduced diameter portion of the needle tube is advanced inside the body in a direction other than the puncture direction to find a suitable position for puncturing the needle tube. Furthermore, by positioning the rod-shaped member so that it overlaps the reduced diameter portion of the needle tube, the reduced diameter portion of the needle tube can be prevented from coming into contact with tissue other than the target tissue, further preventing damage to the tissue.

1 is a side view of a medical puncture needle according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the puncture needle shown in FIG. 1 . FIG. 2 is a front view of the reduced diameter portion of the puncture needle shown in FIG. 1 . 2 is a plan view of a reduced diameter portion of the puncture needle shown in FIG. 1 . FIG. 2 is a bottom view of the reduced diameter portion of the puncture needle shown in FIG. 1 . FIG. 5 is a schematic diagram showing the configuration of a reduced diameter portion of the puncture needle shown in FIG. 4. 6 is a schematic diagram showing the configuration of a reduced diameter portion of the puncture needle shown in FIG. 5. 8 is a cross-sectional view of the reduced diameter portion of the puncture needle shown in FIG. 3 taken along line VIII-VIII. 2 is a half-sectional view of a reduced diameter portion of the puncture needle shown in FIG. 1, showing a half-sectional view of a first side across the central axis of the needle tube. FIG. 4 is a cross-sectional view of the reduced diameter portion of the puncture needle shown in FIG. 3 taken along the line XX. FIG. 10 is a cross-sectional view showing a modified example of the reduced diameter portion of the medical puncture needle according to one embodiment of the present invention. FIG. 10 is a cross-sectional view showing a modified example of the reduced diameter portion of the medical puncture needle according to one embodiment of the present invention. FIG. 13 is a front view of the reduced diameter portion of the puncture needle shown in FIG. 12. FIG. 9 is a cross-sectional view of the puncture needle shown in FIG. 8 to which a second imaginary line and a third imaginary line are added. FIG. 10 is a side view showing a modified example of a medical puncture needle according to an embodiment of the present invention. FIG. 16 is a plan view of the reduced diameter portion of the puncture needle shown in FIG. 15 . FIG. 16 is a bottom view of the reduced diameter portion of the puncture needle shown in FIG. 15 . 1 is a side view (partial cross-sectional view) of a medical device according to an embodiment of the present invention, showing a state in which a rod-shaped member is fixed at a first stop position. FIG. 20 is a side view (partial cross-sectional view) showing a modified example of the medical device shown in FIG. 18, showing a state in which the rod-shaped member is fixed at the second stop position. FIG. 19 is a side view (partial cross-sectional view) showing a modified example of the medical device shown in FIG. 18. FIG. 20 is a side view (partial cross-sectional view) showing a modified example of the medical device shown in FIG. 18, showing a state in which the rod-shaped member has been removed from the needle tube. FIG. 1 is a plan view showing an example of the configuration of a conventional puncture needle. 23 is a bottom view showing an example of the configuration of the puncture needle shown in FIG. 22. FIG. FIG. 23 is a schematic diagram showing the configuration of the puncture needle shown in FIG. 22. FIG. 24 is a schematic diagram showing the configuration of the puncture needle shown in FIG. 23.

The present invention will be described in more detail below based on the following embodiments. However, the present invention is not limited to the following embodiments, and can of course be implemented with appropriate modifications within the scope of the spirit described above and below, all of which are within the technical scope of the present invention. For convenience, hatching and component symbols may be omitted in the drawings. In such cases, please refer to the specification or other drawings. The dimensions of various components in the drawings may differ from their actual dimensions, as priority is given to aiding understanding of the features of the present invention.

The medical puncture needle and medical device according to the present invention may be used to puncture body cavities, blood vessels, organs, etc. for the purposes of injecting medicinal solutions, collecting or draining bodily fluids, etc. in the treatment and diagnosis of various diseases. Hereinafter, the medical puncture needle will be simply referred to as a puncture needle. The puncture needle and medical device have a needle tube. The puncture needle and medical device are preferably used in non-endoscopic procedures, and more preferably for the treatment of cardiac tamponade. The needle tube can be inserted from the chest (e.g., the solar plexus), through the diaphragm near the apex of the heart, and into the pericardial space to appropriately drain bodily fluids that have accumulated between the pericardial spaces.

In puncture needles and medical devices, the distal side refers to the distal end of the needle tube in the longitudinal direction, which is the side to be treated, and the proximal side refers to the proximal end of the needle tube in the longitudinal direction, which is the side closest to the user. When each component is divided into two equal parts longitudinally, the proximal side is sometimes referred to as the proximal portion, and the distal side is sometimes referred to as the distal portion. The side of a puncture needle or medical device refers to the side when the needle tube is oriented in the direction in which the distance between the central axis of the needle tube in the radial direction and the distal end of the needle tube is greatest.

1. Puncture Needle One embodiment of the medical puncture needle according to the present invention is a medical puncture needle having a needle tube with a reduced-diameter portion at its distal portion, wherein in a cross section passing through the central axis of the needle tube when the needle tube is oriented in a direction that maximizes the distance between the central axis and the distal end of the needle tube in the radial direction of the needle tube, a first imaginary line passing through the distal end of the reduced-diameter portion on a first side across the central axis and the distal end of the reduced-diameter portion on a second side across the central axis extends in a direction different from the direction perpendicular to the central axis, and in a half cross section passing through the central axis of the needle tube and on one side of the central axis, when T is the maximum outer radius of the reduced-diameter portion, S is the lumen radius of the needle tube at a part of the reduced-diameter portion with maximum outer radius T, and U is the distance in the radial direction of the needle tube between the distal end of the reduced-diameter portion and the central axis, the following formula (1) is satisfied, and formula (1) is satisfied in all half cross sections at different circumferential positions of the needle tube:
(U-S)<(T-S)/2...(1)
In the medical puncture needle of the present invention, the distal end of the reduced diameter section is likely to be positioned closer to the inner cavity of the needle tube in all half-sections where the circumferential position of the needle tube is different, so even if the outer surface of the needle tube accidentally comes into contact with tissue other than the target to be punctured when the reduced diameter section of the needle tube is advanced and moved in a direction other than the puncture direction to find a suitable position within the body for puncturing with the needle tube, damage to the tissue can be prevented.

The configuration of the puncture needle will be described with reference to Figures 1 to 17. Figure 1 is a side view of a medical puncture needle according to one embodiment of the present invention. Figure 2 is a cross-sectional view of the puncture needle shown in Figure 1. Figures 3 to 5 are a front view, a plan view, and a bottom view, respectively, of the reduced-diameter portion of the puncture needle shown in Figure 1. Figure 6 is a schematic diagram showing the configuration of the reduced-diameter portion of the puncture needle shown in Figure 4. Figure 7 is a schematic diagram showing the configuration of the reduced-diameter portion of the puncture needle shown in Figure 5. Figure 8 is a cross-sectional view taken along VIII-VIII of the reduced-diameter portion of the puncture needle shown in Figure 3. Figure 9 is a half-side cross-sectional view of the reduced-diameter portion of the puncture needle shown in Figure 1, showing a half-side cross-sectional view of the first side across the central axis of the needle tube. Figure 10 is an X-X cross-sectional view of the reduced-diameter portion of the puncture needle shown in Figure 3. Figure 11 is a cross-sectional view showing a modified version of the reduced-diameter portion of a medical puncture needle according to one embodiment of the present invention. Figure 12 is a cross-sectional view showing a modified version of the reduced-diameter portion of a medical puncture needle according to one embodiment of the present invention. Figure 13 is a front view of the reduced-diameter portion of the puncture needle shown in Figure 12. Figure 14 is a cross-sectional view of the puncture needle shown in Figure 8 with second and third imaginary lines added. Figure 15 is a side view showing a modified example of a medical puncture needle according to one embodiment of the present invention. Figure 16 is a plan view of the tapered portion of the puncture needle shown in Figure 15. Figure 17 is a bottom view of the tapered portion of the puncture needle shown in Figure 15.

The puncture needle 5 has a needle tube 6. The needle tube 6 is a long, slender member with a pointed tip. The needle tube 6 has a longitudinal direction x, a radial direction, and a circumferential direction p. The needle tube 6 has an outer surface 8 and an inner surface 9. The needle tube 6 also has a distal end 16 and a proximal end 17 in the longitudinal direction x. The tip of the needle tube 6 faces the distal side. Although Figure 1 shows an example in which the needle tube 6 has a straight shape, at least a portion of the needle tube 6 may be curved to enable application to tissues of various shapes.

As shown in Figures 1-2 and 4-8, the needle tube 6 has a tapered portion 13 at its distal end. The tapered portion 13 of the needle tube 6 functions as a puncture portion for inserting the puncture needle 5 into biological tissue. The tapered portion 13 is a portion whose outer diameter is smaller than the outer diameter at the midpoint of the needle tube 6 in the longitudinal direction x. In the tapered portion 13, it is preferable that the outer diameter of the needle tube 6 gradually decreases toward the distal end 16 of the needle tube 6. The distal end of the tapered portion 13 is preferably located at the most distal point of the needle tube 6.

As shown in Figures 1 and 2, the needle tube 6 may have a tubular portion 14, where the outer diameter of the needle tube 6 is constant, proximal to the reduced diameter portion 13. The tubular portion 14 is preferably disposed adjacent to the reduced diameter portion 13. Although not shown, the needle tube 6 may have a tapered portion, proximal to the tubular portion 14, where the outer diameter decreases toward the distal end 16.

As shown in FIG. 2, the needle tube 6 has a lumen 7 extending from the distal end 16 to the proximal end 17. The lumen 7 may accommodate a rod-shaped member 40, which will be described later, or may be used as a flow path for medicinal solutions to be introduced into the body or bodily fluids to be discharged from the body. It is preferable that one needle tube 6 has only one lumen 7, but multiple lumens may also be provided. It is preferable that the lumen 7 extend to the tapered portion 13.

The cross-sectional shape of the lumen 7 in the radial direction of the needle tube 6 may be, for example, circular, elliptical, polygonal, or a combination of these, or a shape with a portion of these shapes cut out. Elliptical shapes include oval, egg-shaped, and rounded rectangular shapes, and this also applies in the following description. In the radial direction of the needle tube 6, the cross-sectional shape of the lumen 7 in the tapered diameter portion 13 and the cross-sectional shape of the lumen 7 in the tubular portion 14 may be the same or different from each other.

In Figure 2, the needle tube 6 has a distal opening 11 and a proximal opening 12. The distal opening 11 and the proximal opening 12 are connected to the lumen 7. This allows body fluid to be sucked into the lumen 7 through the distal opening 11, and the body fluid taken into the lumen 7 to be discharged through the proximal opening 12. In addition, by connecting a fluid supplier or the like to the proximal opening 12, medicinal fluid or the like can be introduced into the body through the lumen 7 from the distal opening 11. Alternatively, operations such as protruding the rod-shaped member 40 from the distal opening 11 and removing the rod-shaped member 40 from the proximal opening 12 can be performed. The distal opening 11 is preferably located in the tapered section 13.

As shown in Figures 4 and 5, the needle tube 6 has an inner circumference 111 and an outer circumference 112 around the distal opening 11. For ease of understanding, in Figures 4 and 5, the inner circumference 111 is indicated by a dashed line and the outer circumference 112 is indicated by a dashed double-dashed line. The distal end 16 of the needle tube 6 is preferably located on the inner circumference 111 of the needle tube 6 as shown in Figure 3, but may also be located radially outward from the inner circumference 111. However, the distal end 16 of the needle tube 6 is not located on the outline 19 (outline) of the tapered diameter portion 13 of the needle tube 6 when viewed from the front. It can also be said that the distal end 16 of the needle tube 6 is not located on the outer circumference 112.

As shown in Figures 1 and 2, the distal end 16 of the needle tube 6 is ground to form a first blade surface 15 at a predetermined inclination angle relative to the central axis C of the needle tube 6 in the longitudinal direction x. Although not shown, after forming the first blade surface 15, the needle tube 6 may be further ground to form a second blade surface at a predetermined inclination angle relative to the first blade surface 15. Grinding the needle tube 6 in this manner may form a reduced diameter portion 13. Here, the central axis C of the needle tube 6 refers to the central axis of the needle tube 6 in the longitudinal direction x.

The needle tube 6 can be made of metal or resin, but is preferably made of metal. Using metal allows the puncture needle 5 to be sharper, making it easier to puncture biological tissue. The needle tube 6 can be made of metals such as stainless steel, carbon steel, and nickel-titanium alloy, or synthetic resins such as polyolefin resins (e.g., polyethylene and polypropylene), polyamide resins (e.g., nylon), polyester resins (e.g., PET), aromatic polyether ketone resins (e.g., PEEK), polyether polyamide resins, polyurethane resins, polyimide resins, and fluororesins (e.g., PTFE, PFA, ETFE). These materials may be used alone or in combination. The tapered portion 13 and the tube portion 14 may be made of the same material or different materials.

As shown in FIG. 8 , in a cross section passing through the central axis C of the needle tube 6 when the needle tube 6 is oriented in a direction that maximizes the distance between the central axis C and the distal end 16 of the needle tube 6 in the radial direction of the needle tube 6, a first imaginary line 23 passing through the distal end 131 of the reduced diameter portion 13 on the first side 21 across the central axis C and the distal end 132 of the reduced diameter portion 13 on the second side 22 across the central axis C extends in a direction different from the direction perpendicular to the central axis C. The first imaginary line 23 extends in a direction perpendicular to the central axis C of the needle tube 6, i.e., non-parallel to the radial direction of the needle tube 6. This configuration makes it easier to puncture the reduced diameter portion 13 into the target tissue.

As shown in Figure 9, in a cross section passing through the central axis C of the needle tube 6 and located on one side of the central axis C, when the maximum outer radius of the reduced diameter portion 13 is T, the inner lumen radius of the needle tube 6 at the part of the reduced diameter portion 13 where the maximum outer radius T is S, and the distance between the distal end 133 of the reduced diameter portion 13 and the central axis C in the radial direction of the needle tube 6 is U, the following equation (1) is satisfied, and the following equation (1) is satisfied in all half-side cross sections at different positions in the circumferential direction p of the needle tube 6.
(U-S)<(T-S)/2...(1)

In equation (1), "U-S" is the difference between the lumen radius S of the needle tube 6 at the portion of the tapered diameter section 13 with the maximum outer radius T in the half cross section and the distance U between the distal end 133 of the tapered diameter section 13 and the central axis C. It is the distance in the direction perpendicular to the central axis C from the wall surface (inner surface 9) of the lumen 7 of the needle tube 6 at the portion of the tapered diameter section 13 with the maximum outer radius T to the distal end 133 of the tapered diameter section 13. If there are multiple portions of the tapered diameter section 13 with the maximum outer radius T in the longitudinal direction x, the largest lumen radius among them is taken as S. In equation (1), "T-S" is the wall thickness of the needle tube 6 at the portion of the tapered diameter section 13 with the maximum outer radius T in the half cross section. Furthermore, in equation (1), "(T-S)/2" represents half the length of the wall thickness in the half cross section. Therefore, equation (1) indicates that the distal end 133 of the tapered diameter portion 13 is positioned so that the distance in the direction perpendicular to the central axis C from the wall surface (inner surface 9) of the lumen 7 of the needle tube 6 at the point of maximum outer radius T of the tapered diameter portion 13 to the distal end 133 of the tapered diameter portion 13 is shorter than half the length of the wall thickness.

In the puncture needle 5, the distal end 133 of the tapered portion 13 is located radially inward relative to the outer periphery of the tapered portion 13 in all half-sections at different positions in the circumferential direction p of the needle tube 6. Therefore, even if the outer surface 8 of the needle tube 6 accidentally contacts tissue other than the target tissue to be punctured when the tapered portion 13 of the needle tube 6 is advanced and moved in a direction other than the puncture direction within the body to find a suitable puncture position (e.g., when the tip of the needle tube 6 is rotated around a point approximately midway along the needle tube 6 to change its axial direction), the tissue is prevented from being damaged. This allows the needle tube 6 to be moved relatively freely within the body, allowing the puncture position to be identified appropriately and in a short time. Figure 9 shows a half-section of the first side 21 of the needle tube 6 across the central axis C as an example of a half-section, so the distal end 133 in the half-section coincides with the distal end 131 of the tapered portion 13 on the first side 21. Figure 9 also shows an example where U = S.

It can also be seen from Figure 10 that equation (1) is satisfied in all half-sections where the position of the circumferential direction p of the needle tube 6 is different. Figure 10 shows a cross section perpendicular to the cross section shown in Figure 8. In Figure 10, equation (1) is satisfied in both the half-section on the upper side of the paper across the central axis C and the half-section on the lower side of the paper across the central axis C. In this way, the puncture needle 5 satisfies equation (1) in all half-sections where the position of the circumferential direction p of the needle tube 6 is different.

In a cross section passing through the central axis C of the needle tube 6 and located on one side of the central axis C, when the maximum outer radius of the reduced diameter portion 13 is T, the inner lumen radius of the needle tube 6 at the part of the reduced diameter portion 13 with the maximum outer radius T is S, and the distance between the distal end 133 of the reduced diameter portion 13 and the central axis C in the radial direction of the needle tube 6 is U, the needle tube 6 satisfies the following equation (2), and the following equation (2) may be satisfied in all half-side cross sections at different positions in the circumferential direction p of the needle tube 6.
(U-S)<(T-S)/4...(2)
In formula (2), "(T-S)/4" represents a quarter of the wall thickness in the half cross section. Therefore, formula (2) indicates that the distal end 133 of the reduced diameter portion 13 is disposed so that the distance in the direction perpendicular to the central axis C from the wall surface (inner surface 9) of the lumen 7 of the needle tube 6 at the proximal end 134 of the reduced diameter portion 13 to the distal end 133 of the reduced diameter portion 13 is shorter than a quarter of the wall thickness. This configuration makes it even easier for the distal end 133 of the reduced diameter portion 13 to be disposed radially inward relative to the outer periphery of the reduced diameter portion 13 in all half cross sections at different positions in the circumferential direction p of the needle tube 6. As a result, the puncture hole formed in the biological tissue by puncture can be made smaller, and puncture pain can also be suppressed.

In Figures 6 to 7, the portions 113 where the cutting edge angle is an acute angle are indicated by thick lines, the portions 114 where the cutting edge angle is an obtuse angle are indicated by thinner lines, and the portions 115 other than the cutting edge are indicated by dashed lines. As can be seen from Figures 4 to 7, the inner circumference 111 side of the distal opening 11 of the needle tube 6 only has the portions 113 where the cutting edge angle is an acute angle, and does not have the portions 114 where the cutting edge angle is an obtuse angle. Furthermore, the outer circumference 112 side only has the portions 114 where the cutting edge angle is an obtuse angle, and does not have the portions 113 where the cutting edge angle is an acute angle. Therefore, even if the outer surface 8 of the needle tube 6 accidentally comes into contact with tissue other than the tissue to be punctured when the reduced diameter portion 13 of the needle tube 6 is advanced inside the body in a direction other than the puncture direction to find a suitable position for puncturing the needle tube 6, damage to that tissue can be prevented.

As shown in Figure 3, on the front view of the needle tube 6 viewed from the distal end 16 side, the needle tube 6 preferably has an opening edge 18 consisting of the distal ends 133 of all the tapered portions 13 on one cross section that are located at different positions in the circumferential direction p of the needle tube 6. Because the opening edge 18 consists of the distal ends 133 of all the tapered portions 13 on one cross section that are located at different positions in the circumferential direction p of the needle tube 6, it has a closed shape in the circumferential direction p on the front view. In other words, the opening edge 18 is a portion that continues uninterrupted in the circumferential direction p.

On the front surface, the shape of the opening edge 18 can be circular, elliptical, polygonal, or a combination of these, but a loop shape is preferable, and a circular or elliptical shape is more preferable. On the front surface, the shape of the opening edge 18 may be the same as the shape of the radial cross section of the lumen 7 (particularly the lumen 7 at the proximal end of the tapered portion 13), or may be different from the shape of the lumen 7.

As shown in Figure 3, the needle tube 6 preferably has an annular portion 26 on the front surface that is located radially outward of the opening edge 18 of the reduced diameter portion 13. By having this annular portion 26, the opening edge 18 is located radially inward of the contour 19 of the reduced diameter portion 13 on the front surface. The annular portion 26 is formed so as to surround the needle tube 6 in a closed ring shape. Because the annular portion 26 extends over the entire circumferential direction p of the needle tube 6, an interruption in the circumferential direction p does not qualify as an annular portion 26. As shown in Figures 1 and 3 to 5, the annular portion 26 extends in the longitudinal direction x of the needle tube 6 at all positions in the circumferential direction p of the needle tube 6.

The distal end 16 of the needle tube 6 is preferably ground at a predetermined inclination angle with respect to the central axis C in the longitudinal direction x of the needle tube 6 to form the first blade surface 15. Therefore, the length of the annular portion 26 in the longitudinal direction x of the needle tube 6 may vary depending on the position in the circumferential direction p of the needle tube 6. It is preferable that the normal direction of the outer surface 8 of the needle tube 6 in the annular portion 26 extends in a direction different from the radial direction of the needle tube 6.

The annular portion 26 is preferably formed by grinding a portion of the needle tube 6. More preferably, the annular portion 26 is formed by forming a first blade surface 15 inclined at a predetermined angle relative to the central axis C, and then grinding the needle tube 6 in the circumferential direction p. The annular portion 26 is preferably ground so that it extends continuously over 360° in the circumferential direction p of the needle tube 6.

It is preferable that one or more curved portions 27 are arranged on the outer surface 8 of the needle tube 6 in the annular portion 26. This configuration prevents damage to tissue even if the outer surface 8 of the annular portion 26 accidentally comes into contact with tissue other than the target tissue to be punctured when the reduced-diameter portion 13 of the needle tube 6 is advanced inside the body in a direction other than the puncture direction to find a suitable position for puncturing with the needle tube 6.

As shown in Figures 1 and 3 to 5, it is more preferable that the outer surface 8 of the needle tube 6 in the annular portion 26 is composed of only one curved surface portion 27. One curved surface portion 27 is a curved surface portion that is continuous without any surface changes on the outer surface 8 of the needle tube 6 in the annular portion 26. In other words, one curved surface portion 27 is a surface that is continuous 360° in the circumferential direction p of the needle tube 6. This configuration further prevents damage to tissue other than the target tissue, even if the outer surface 8 of the annular portion 26 accidentally comes into contact with that tissue.

Although not shown, one or more flat surfaces may be arranged on the outer surface 8 of the needle tube 6 in the annular portion 26. One or more curved surfaces 27 and one or more flat surfaces may be arranged on the outer surface 8 of the needle tube 6 in the annular portion 26.

As can be seen from Figures 1 and 3 to 5, it is preferable that the outer surface 8 of the needle tube 6 in the annular portion 26 does not have an edge. This configuration further prevents damage to tissue other than the target tissue, even if the outer surface 8 of the annular portion 26 accidentally comes into contact with that tissue.

The edge portion is formed by at least one of the intersection lines of two flat surfaces, two curved surfaces, and a flat surface and a curved surface. The angle between the two surfaces that form the edge portion is not particularly limited, but may be, for example, greater than or equal to 5° and less than 180°.

The annular portion 26 may have an edge on the outer surface 8 of the needle tube 6. In this case, the edge preferably exists radially inward of the outer peripheral envelope of the annular portion 26. For example, FIG. 11 shows an example in which, in a radial cross section of the annular portion 26, the annular portion 26 has multiple convex portions 28 that convex outward in the radial direction of the needle tube 6, and the multiple convex portions 28 are aligned in the circumferential direction p of the needle tube 6. The convex portions 28 correspond to the curved surface portion 27. The edge portion, which is the intersection line of adjacent convex portions 28 in the circumferential direction p, is depicted as a valley portion 29 in FIG. 11. In FIG. 11, the outer peripheral envelope 30 corresponds to the outer peripheral envelope. Because the valley portions 29 exist radially inward of the outer peripheral envelope 30, even if the outer surface 8 of the annular portion 26 accidentally comes into contact with tissue other than the target tissue, the edge is less likely to come into contact with the tissue, preventing damage to the tissue other than the target tissue.

As can be seen from Figures 12 and 13, U≠S may be satisfied in at least one half-section that is a cross section passing through the central axis C of the needle tube 6 and is on one side of the central axis C. More specifically, U>S may be satisfied. In other words, the distal end 133 of the reduced diameter section 13 may be located radially outward of the minimum inner circumference of the reduced diameter section 13 of the needle tube 6. Even if the distal end 133 of the reduced diameter section 13 is located in such a position, as long as formula (1) is satisfied, the outer surface 8 of the needle tube 6 can be prevented from damaging tissue other than the tissue to be punctured.

U may be equal to S in all half-sections where the needle tube 6 has a different position in the circumferential direction p. Also, U may be equal to S in all half-sections where the needle tube 6 has a different position in the circumferential direction p. Furthermore, U may be equal to S in multiple half-sections where the needle tube 6 has a different position in the circumferential direction p, and U may be equal to S in the remaining multiple half-sections.

As shown in FIG. 14 , in a cross section of the reduced diameter portion 13 passing through the central axis C of the needle tube 6 when the needle tube 6 is oriented in a direction that maximizes the distance between the central axis C and the distal end 16 of the needle tube 6 in the radial direction of the needle tube 6, the angle α between the second imaginary line 24 and the central axis C may be greater than the angle β between the third imaginary line 25 and the central axis C. Here, the first side 21 is the side whose distal end is located more distally than the second side 22, the second imaginary line 24 is a line passing through the distal end 261 and the proximal end 262 of the annular portion 26 on the first side 21, and the third imaginary line 25 is a line passing through the distal end 263 and the proximal end 264 of the annular portion 26 on the second side 22. Setting the angle between the second imaginary line 24 and the third imaginary line 25 in this manner makes it easier to insert the puncture needle 5 into the target tissue.

In a cross section of the reduced diameter portion 13 passing through the central axis C of the needle tube 6, when the needle tube 6 is oriented in a direction in which the distance between the central axis C and the distal end 16 of the needle tube 6 in the radial direction of the needle tube 6 is greatest, the angle α may be 1.1 times or more, 1.2 times or more, or 1.5 times or more, or may be 3 times or less, 2.8 times or less, or 2.5 times or less, of the angle β.

The needle tube 6 may be provided with an element that makes it easier to identify the position of the tapered portion 13 of the needle tube 6 within the body. For example, as shown in FIG. 15 , the needle tube 6 may have, on its outer surface 8, a first region 31 and a second region 32 located distal to the first region 31 and having a greater surface roughness than the first region 31. The distal end 321 of the second region 32 may be located distal to a first position 35 located proximal to the proximal end 132 of the tapered portion 13 by a length L1 in the longitudinal direction x of the needle tube 6. Because the second region 32 has a greater surface roughness than the first region 31, ultrasound is more easily reflected by the second region 32. Furthermore, because the distal end 321 of the second region 32 is located distal to the first position 35, the second region 32 functions as an ultrasonic marker that indicates the position of the tapered portion 13 of the needle tube 6. Therefore, by checking the position of the second region 32 on an ultrasound image, it becomes easier to determine the position of the reduced diameter portion 13 of the needle tube 6 inside the body.

The surface roughness is the arithmetic mean roughness Ra over the reference length of the roughness curve on the outer surface 8 of the needle tube 6. The arithmetic mean roughness Ra corresponds to the arithmetic mean roughness Ra specified in JIS B 0601 (2001) and is measured in accordance with JIS B 0633 (2001). A measuring instrument specified in JIS B 0651 (2001) (for example, a Keyence VK-9510 laser microscope) is used for the measurement. This also applies to the following explanation.

Methods for increasing the surface roughness of the second region 32 compared to the first region 31 include mechanically or chemically roughening the surfaces, such as blasting, etching, or using a wire brush or sandpaper.

The surface roughness of the second region 32 is preferably at least twice the surface roughness of the first region 31, more preferably at least five times, and even more preferably at least 10 times; it is also acceptable for the surface roughness to be no more than 500 times, no more than 100 times, or no more than 20 times.

The distal end 321 of the second region 32 may be located distal to the proximal end 132 of the tapered portion 13. The distal end 321 of the second region 32 may be located at the most distal position of the needle tube 6. The proximal end 322 of the second region 32 may be located distal to the first position 35. The proximal end 322 of the second region 32 may also be located proximal to the first position 35. In the longitudinal direction x, the length of the second region 32 is preferably longer than the length of the tapered portion 13.

The second region 32 may be disposed only in a portion of the circumferential direction p of the needle tube 6. However, as can be seen from Figures 15 to 17, it is preferable that the second region 32 be disposed over the entire circumferential direction p of the needle tube 6. By disposing the second region 32 in this manner, it becomes easier to confirm the position of the reduced diameter portion 13 in an ultrasound image regardless of the direction in which the needle tube 6 is facing.

As shown in Figures 16 and 17, it is preferable that the second region 32 is not disposed around the opening edge 18. It is also more preferable that the second region 32 is not disposed in the annular portion 26. In particular, it is preferable that the surface roughness of the outer surface 8 of the annular portion 26 is smaller than the surface roughness of the second region 32. This further prevents damage to tissue other than the target tissue, even if the outer surface 8 of the annular portion 26 accidentally comes into contact with that tissue.

A needle tube 6 without the second region 32 in the annular portion 26 can be formed, for example, by the following procedure: The second region 32 is formed on the outer surface of the tube used to form the needle tube 6, the tip of the tube is then cut to form the first cutting edge 15, thereby forming the reduced diameter portion 13, and then the reduced diameter portion 13 is ground in the circumferential direction p to form the annular portion 26.

As shown in Figures 15 to 17, the second region 32 may be arranged proximal to the annular portion 26. It is preferable that the second region 32 be arranged adjacent to the annular portion 26 at the distal portion of the second region 32. By locating the second region 32 close to the annular portion 26 in this manner, it becomes easier to confirm the position of the tapered portion 13 in an ultrasound image.

As can be seen from Figure 15, the annular portion 26 is arranged so as to be inclined with respect to the central axis C of the needle tube 6 in a side view of the needle tube 6. Therefore, in the longitudinal direction x of the needle tube 6, the distal end 321 of the second region 32 may be arranged distal to the proximal end of the annular portion 26.

2. Medical Device The present invention also provides a medical device. The configuration of the medical device will be described with reference to Figures 18 to 21. Figure 18 is a side view (partially cross-sectional) of a medical device according to one embodiment of the present invention, showing a state in which the rod-shaped member is fixed at the first stop position. Figure 19 is a side view (partially cross-sectional) of a modified version of the medical device shown in Figure 18, showing a state in which the rod-shaped member is fixed at the second stop position. Figure 20 is a side view (partially cross-sectional) of a modified version of the medical device shown in Figure 18. Figure 21 is a side view (partially cross-sectional) of a modified version of the medical device shown in Figure 18, showing a state in which the rod-shaped member has been removed from the needle tube.

The medical device 1 includes a needle tube 6 having a reduced diameter portion 13 at its distal portion, and a rod-shaped member 40 disposed in the lumen 7 of the needle tube 6 and movable in the longitudinal direction x of the needle tube 6 relative to the needle tube 6. As shown in Fig. 8 , in a cross section passing through the central axis C of the needle tube 6 when the needle tube 6 is oriented in a direction in which the distance between the central axis C and the distal end 16 of the needle tube 6 in the radial direction of the needle tube 6 is maximized, a first imaginary straight line 23 passing through the distal end 131 of the reduced diameter portion 13 on the first side 21 across the central axis C and the distal end 132 of the reduced diameter portion 13 on the second side 22 across the central axis C extends in a direction different from the direction perpendicular to the central axis C, and as shown in Fig. 9 As shown in the figure, in a cross section passing through the central axis C of the needle tube 6 and located on one side of the central axis C, when the maximum outer radius of the reduced diameter portion 13 is T, the inner lumen radius of the needle tube 6 at the part of the reduced diameter portion 13 with the maximum outer radius T is S, and the distance between the distal end 133 of the reduced diameter portion 13 and the central axis C in the radial direction of the needle tube 6 is U, the following equation (1) is satisfied, and the following equation (1) is satisfied in all half-side cross sections at different positions in the circumferential direction p of the needle tube 6.
(U-S)<(T-S)/2...(1)
In the medical device 1, the distal end 133 of the reduced diameter portion 13 is located radially inward of the outer periphery of the reduced diameter portion 13 in all half cross sections at different positions in the circumferential direction p of the needle tube 6, so that when the reduced diameter portion 13 of the needle tube 6 is advanced inside the body in a direction other than the puncture direction to find a suitable position for puncturing with the needle tube 6 (for example, when the tip of the needle tube 6 is rotated around approximately one intermediate point of the needle tube 6 as a rotation center to change the axial direction), even if the outer surface 8 of the needle tube 6 accidentally comes into contact with tissue other than the target to be punctured, the tissue can be prevented from being damaged. Furthermore, in the medical device 1, the rod-shaped member 40 is located in the lumen 7 of the needle tube 6, and by positioning the rod-shaped member 40 so as to overlap the reduced diameter portion 13 of the needle tube 6, the reduced diameter portion 13 of the needle tube 6 can be prevented from coming into contact with tissue other than the target to be punctured, thereby further preventing the tissue from being damaged. Furthermore, by appropriately adjusting the position of the rod-shaped member 40 relative to the needle tube 6, it is possible to prevent living tissue cut off by puncture from entering the lumen 7 of the needle tube 6. For other configurations of the needle tube 6, please refer to the explanation in "1. Medical puncture needle."

The rod-shaped member 40 is used to detect a suitable site for puncturing the needle tube 6 by the feel when its distal end comes into contact with biological tissue. The rod-shaped member 40 may be any long, thin member, and there are no particular restrictions on its axial length or thickness. The rod-shaped member 40 has a longitudinal direction, a radial direction, and a circumferential direction. The rod-shaped member 40 has a distal end 42 and a proximal end. It is preferable that the rod-shaped member 40 has a linear shape so that it can easily move relative to the needle tube 6 in the longitudinal direction x of the needle tube 6.

The rod-shaped member 40 may have a solid shape. This makes it easier to impart rigidity to the rod-shaped member 40. The rod-shaped member 40 may also have a hollow shape. For example, the rod-shaped member 40 may have an inner cavity extending in its longitudinal direction. This makes it possible to impart flexibility to the rod-shaped member 40.

For example, as shown in Figures 18 and 19, it is preferable that the rod-shaped member 40 has a blunted shape at its distal end. This makes it easier to avoid damage to biological tissue by the distal end of the rod-shaped member 40. The specific shape of the distal end of the rod-shaped member 40 is not particularly limited, but examples include a cylindrical shape, an elongated cylindrical shape, a hemispherical shape, a spherical shape, an oval spherical shape, or a combination of these. The distal end of the rod-shaped member 40 may have an outer diameter that decreases toward the tip. Examples of such shapes include truncated pyramid shapes, truncated cones, elongated truncated cones, and truncated rounded cones. The shape of the portion of the rod-shaped member 40 proximal to the distal end may be a cylindrical shape, an elongated cylindrical shape, a polygonal prism, or any of these shapes that decrease in diameter toward the distal end. In Figures 18 and 19, the distal end of the rod-shaped member 40 has a hemispherical shape, and the portion proximal to the distal end has a cylindrical shape.

For the material constituting the rod-shaped member 40, the description of the material constituting the needle tube 6 can be referred to as appropriate. The rod-shaped member 40 may be made of the same material as the needle tube 6, or may be made of a different material from the needle tube 6. The distal end of the rod-shaped member 40 and the portion proximal to the distal end may be made of different materials.

The configuration for changing the position of the rod-shaped member 40 relative to the needle tube 6 is not particularly limited. For example, the medical device 1 may have a handle body 51 located at the proximal portion of the needle tube 6 or more proximal to the needle tube 6, and a slider 55 located at the proximal portion of the rod-shaped member 40 or more proximal to the rod-shaped member 40. The rod-shaped member 40 can be protruded from the needle tube 6 by sliding the slider 55 distally. The rod-shaped member 40 can be retracted into the needle tube 6 by sliding the slider 55 proximally.

The handle body 51 and slider 55 can each be composed of one or more components. The handle body 51 can be equipped with a connection mechanism such as a luer lock or coupler, through which an injector, suction device, drainage bag, three-way stopcock, extension tube, etc. can be connected as needed.

The handle body 51 and the slider 55 may be made of synthetic resins such as polyolefin resins such as polypropylene (PP) and polyethylene (PE), polyester resins such as polyethylene terephthalate (PET), polycarbonate resin, ABS resin, and polyurethane resin. The handle body 51 and the slider 55 may be made of the same or different materials.

As shown in Figures 18 and 19, the medical device 1 preferably further includes a stopper that fixes the position of the rod-shaped member 40 in the longitudinal direction x relative to the needle tube 6. This prevents the rod-shaped member 40 from moving against the user's will during the procedure, allowing the procedure to be performed safely.

The mechanism of the stopper is not particularly limited. For example, in Figures 18 and 19, a part of the handle body 51 and a part of the slider 55 function as the stopper. The handle body 51 has a hollow portion extending in the longitudinal direction x. The handle body 51 has an overall cylindrical shape. An opening 53 that communicates with the hollow portion is formed in the peripheral wall of the handle body 51. The slider 55 is disposed in the hollow portion, and a part of the slider 55 is exposed through the opening 53. The slider 55 is configured to move in the longitudinal direction x relative to the handle body 51. By moving the slider 55 distally relative to the handle body 51, the rod-shaped member 40 can be moved distally. By moving the slider 55 proximally relative to the handle body 51, the rod-shaped member 40 can be moved proximally.

When the needle tube 6 has an opening edge 18, as shown in FIG. 18 , the rod-shaped member 40 is preferably fixed by a stopper to the first stop position, where the rod-shaped member 40 is located inside the opening edge 18. The rod-shaped member 40 being located inside the opening edge 18 means that the rod-shaped member 40 is stored within the needle tube 6 and cannot be seen in a side view of the medical device 1. By fixing the rod-shaped member 40 in this position, the rod-shaped member 40 does not obstruct the puncture by the needle tube 6. Furthermore, storing the rod-shaped member 40 within the needle tube 6 can also prevent biological tissue excised by the puncture from entering the lumen 7 of the needle tube 6. In the example of FIG. 18 , the slider 55 can be moved to the proximal end and the proximal end of the slider 55 abuts against the proximal wall portion 532 of the opening 53 of the handle body 51, thereby stopping the rod-shaped member 40 at the second stop position.

When the needle tube 6 has an opening edge 18, as shown in FIG. 19 , it is preferable that the rod-shaped member 40 be fixed by a stopper at the second stop position, where the rod-shaped member 40 protrudes from the opening edge 18. The rod-shaped member 40 protruding from the opening edge 18 means that at least a portion of the rod-shaped member 40 is present outside the needle tube 6 in a side view of the medical device 1. Fixing the rod-shaped member 40 in this position prevents the reduced diameter portion 13 of the needle tube 6 from coming into contact with tissue other than the target tissue, thereby further preventing damage to the tissue. In the example of FIG. 19 , the slider 55 can be moved to the distal end and the distal end of the slider 55 abuts against the distal wall portion 531 of the opening 53 of the handle body 51, thereby stopping the rod-shaped member 40 at the first stop position.

Although not shown, the stopper may be composed of a convex portion or a concave portion provided on the surface of the handle body 51 facing the slider 55 and the surface of the slider 55 facing the handle body 51. For example, the handle body 51 may have a handle body-side convex portion on the surface facing the slider 55, and the slider 55 may have a slider-side convex portion on the surface facing the handle body 51, and the position where the handle body-side convex portion and the slider-side convex portion abut when the slider 55 is moved in the longitudinal direction x may be defined as the first stop position or the second stop position.

The shapes of the handle body convex portion, handle body concave portion, slider convex portion, and slider concave portion can be selected appropriately depending on the shapes of the handle body 51 and slider 55. For example, if the handle body 51 or slider 55 has a cylindrical portion, the convex portion or concave portion may be arranged on the circumference of a cross section perpendicular to the longitudinal direction of the cylindrical portion. In this case, one or more convex portions or concave portions may be arranged on the circumference.

Although not shown, the stopper may be composed of a convex or concave portion arranged on the inner surface 9 of the needle tube 6 and a concave or convex portion arranged on the outer surface 41 of the rod-shaped member 40. For the abutment relationship between the convex and concave portions, please refer to the description of the handle body 51 and slider 55.

The rod-shaped member 40 may be provided with elements that make it easier to determine the position of the rod-shaped member 40 within the body. For example, as shown in FIG. 20, the rod-shaped member 40 preferably has, on the outer surface 41 of its distal end, a third region 43 and a fourth region 44 that is located distal to the third region 43 and has a greater surface roughness than the third region 43. Because the fourth region 44 has a greater surface roughness than the third region 43, ultrasound waves are more likely to be reflected by the fourth region 44. Therefore, by checking the position of the fourth region 44 on an ultrasound image, it is easier to determine the position of the distal end of the rod-shaped member 40 within the body.

The surface roughness of the third region 43 and fourth region 44 can be measured in the same manner as for the first region 31 and second region 32.

Methods for making the surface roughness of the fourth region 44 greater than that of the third region 43 include mechanically or chemically roughening the surfaces, such as blasting, etching, or using a wire brush or sandpaper.

The surface roughness of the fourth region 44 is preferably at least twice the surface roughness of the third region 43, more preferably at least five times, and even more preferably at least 10 times; it is also acceptable for the surface roughness to be no more than 100 times, no more than 50 times, or no more than 20 times.

The surface roughness of the fourth region 44 may be greater or less than the surface roughness of the second region 32. The surface roughness of the fourth region 44 may also match the surface roughness of the second region 32. The surface roughness of the third region 43 may be greater or less than the surface roughness of the first region 31. The surface roughness of the third region 43 may also match the surface roughness of the first region 31. In the longitudinal direction of the rod-shaped member 40, the length of the fourth region 44 may be greater or shorter than the length of the second region 32.

As shown in FIG. 20 , the distal end 441 of the fourth region 44 may be located at the most distal end of the rod-shaped member 40. This makes it even easier to grasp the position of the distal end 42 of the rod-shaped member 40. The distal end 441 of the fourth region 44 may also be located closer to the proximal side than the distal end 42 of the rod-shaped member 40.

The fourth region 44 may be arranged only on a portion of the circumference of the rod-shaped member 40, but as can be seen from Figure 20, it is preferable that the fourth region 44 be arranged over the entire circumference of the rod-shaped member 40. By arranging the fourth region 44 in this manner, the position of the fourth region 44 can be easily confirmed in an ultrasound image regardless of the direction in which the rod-shaped member 40 is facing.

If the needle tube 6 has the second region 32, when the rod-shaped member 40 is moved to the most distal position relative to the needle tube 6, the proximal end 442 of the fourth region 44 may be located distal to the distal end 321 of the second region 32. Also, when the rod-shaped member 40 is moved to the most distal position relative to the needle tube 6, the proximal end 442 of the fourth region 44 may be located proximal to the distal end 321 of the second region 32.

As shown in Figure 20, when the rod-shaped member 40 is moved to its most distal position relative to the needle tube 6, it is preferable that the proximal end 442 of the fourth region 44 be located distal to the distal end 16 of the needle tube 6. This configuration makes it easier to identify the position of the rod-shaped member 40 relative to the needle tube 6 in the longitudinal direction x.

As shown in Figure 21, it is preferable that the rod-shaped member 40 be removable from the proximal end 17 of the needle tube 6. By removing the rod-shaped member 40 from the proximal end 17 of the needle tube 6, the lumen 7 of the needle tube 6 can be used not only as an insertion passage for the rod-shaped member 40 but also as a flow path for discharging bodily fluids.

When treating cardiac tamponade, medical device 1 can be used in the following manner.

First, the needle tube 6 is inserted into the epigastric region (Step S1). At this time, it is preferable that the rod-shaped member 40 is positioned inside the opening edge 18, as shown in Figure 18. Furthermore, if the needle tube 6 has a second region 32, it is preferable to insert the needle tube 6 while checking the position of the reduced diameter portion 13 of the needle tube 6 using an ultrasound imaging diagnostic device. In Step S1, the distal end 16 of the needle tube 6 is inserted until it reaches the abdominal cavity.

The rod-shaped member 40 is moved distally in the longitudinal direction x of the needle tube 6 relative to the needle tube 6, causing the rod-shaped member 40 to protrude from the opening edge 18 of the needle tube 6 as shown in Figure 19 (Step S2). In Step S2, the rod-shaped member 40 is inserted until its distal end reaches the abdominal cavity.

With the rod-shaped member 40 protruding from the opening edge 18 of the needle tube 6, the distal end of the rod-shaped member 40 is brought into contact with biological tissue (Step S3). The appropriate site for puncture is detected based on the sensation felt when the rod-shaped member 40 comes into contact with the biological tissue. The appropriate site for puncture is the diaphragm near the apex of the heart. When bringing the rod-shaped member 40 into contact with biological tissue, the rod-shaped member 40 may be moved in a direction different from the direction of puncture by advancing the needle tube 6. For example, the tip of the rod-shaped member 40 may be rotated around an arbitrary midpoint of the rod-shaped member 40 to change its axial direction. If the rod-shaped member 40 has a fourth region 44, it is preferable to perform detection using the rod-shaped member 40 while confirming the position of the distal end 42 of the rod-shaped member 40 using an ultrasound imaging diagnostic device. In this case, it is preferable that the distal end of the rod-shaped member 40 has a blunt shape. Since the rod-shaped member 40 is less likely to damage biological tissue even when it comes into contact with the tissue, the rod-shaped member 40 can be safely advanced within the abdominal cavity.

The needle tube 6 is moved distally in the longitudinal direction x relative to the rod-shaped member 40 to puncture the diaphragm and the pericardial membrane on the diaphragm side (step S4). At this time, it is preferable to move the needle tube 6 while fixing the position of the rod-shaped member 40 inside the body. For example, it is preferable to move the needle tube 6 while the rod-shaped member 40 is in contact with the area to be punctured.

The rod-shaped member 40 is moved proximally in the longitudinal direction x of the needle tube 6, and the rod-shaped member 40 is removed from the proximal end 17 of the needle tube 6 as shown in Figure 21 (Step S5). At this time, it is preferable to move the rod-shaped member 40 while keeping the position of the needle tube 6 fixed inside the body.

The body fluid between the two layers of the pericardial membrane is drained to the outside of the body through the lumen 7 of the needle tube 6 (step S6).

1: Medical device 5: Puncture needle 6: Needle tube 13: Reduced diameter portion 18: Opening edge 21: First side 22: Second side 23: First imaginary straight line 24: Second imaginary straight line 25: Third imaginary straight line 26: Annular portion 27: Curved surface portion
40: Rod-shaped member C: Central axis

Claims (13)

A medical device used to treat cardiac tamponade by draining fluid accumulated between the pericardial membranes,
a needle tube having a reduced diameter portion and a distal opening at a distal portion;
a rod-shaped member disposed in the lumen of the needle tube, movable relative to the needle tube in the longitudinal direction of the needle tube , and having a blunted shape at a distal end thereof ;
the rod-shaped member is adapted to bring a distal end of the rod-shaped member into contact with biological tissue in a state in which the rod-shaped member protrudes from the distal opening of the needle tube, and is movable from a state in which the rod-shaped member is positioned most distally relative to the needle tube toward a proximal side relative to the needle tube, and the rod-shaped member is capable of being pulled out from the proximal end side of the needle tube,
By removing the rod-shaped member from the proximal end side of the needle tube, the lumen of the needle tube is used as a discharge flow path for the bodily fluid,
In a cross section passing through a central axis of the needle tube when the needle tube is oriented in a direction in which the distance between the central axis and the distal end of the needle tube in the radial direction of the needle tube is maximized, a first imaginary line passing through the distal end of the reduced diameter portion on a first side across the central axis and the distal end of the reduced diameter portion on a second side across the central axis extends in a direction different from the direction perpendicular to the central axis,
A medical device in which, in a cross section passing through the central axis of the needle tube and located on one side of the central axis, the maximum outer radius of the reduced diameter portion is T, the inner radius of the needle tube at the part of the maximum outer radius T is S, and the distance between the distal end of the reduced diameter portion and the central axis in the radial direction of the needle tube is U, the following formula (1) is satisfied, and the following formula (1) is satisfied in all half-side cross sections at different circumferential positions of the needle tube.
(U-S)<(T-S)/2...(1) When viewed from the distal end side of the needle tube, the needle tube has an opening edge formed by a collection of distal ends of the reduced diameter portions of all half cross sections that are located at different circumferential positions of the needle tube,
the needle tube has, on the front surface, a ring-shaped portion of the reduced diameter portion that is disposed radially outward of the opening edge of the needle tube,
The medical device according to claim 1, wherein the outer surface of the needle tube in the annular portion has one or more curved portions. The medical device according to claim 2, wherein the outer surface of the needle tube in the annular portion has no edge portion. 4. The medical device according to claim 2 or 3, wherein in a cross section of the reduced diameter portion passing through the central axis of the needle tube, when the needle tube is oriented in a direction in which the distance between the central axis and the distal end of the needle tube in the radial direction of the needle tube is greatest, the angle between a second imaginary line and the central axis is larger than the angle between a third imaginary line and the central axis.
Here, the first side is the side whose distal end is located further away than the second side, the second imaginary line is a line passing through the distal end and proximal end of the annular portion on the first side, and the third imaginary line is a line passing through the distal end and proximal end of the annular portion on the second side. The needle tube has, on its outer surface, a first region and a second region located distal to the first region and having a surface roughness greater than that of the first region;
The medical device according to any one of claims 1 to 4, wherein the distal end of the second region is located distal to a first position that is located proximal to the proximal end of the reduced diameter portion by the longitudinal length of the needle tube of the reduced diameter portion. The medical device according to claim 5, wherein the second region is disposed around the entire circumference of the needle tube. When viewed from the distal end side of the needle tube, the needle tube has an opening edge formed by a collection of distal ends of the reduced diameter portions of all half cross sections that are located at different circumferential positions of the needle tube,
the needle tube has, on the front surface, a ring-shaped portion of the reduced diameter portion that is disposed radially outward of the opening edge of the needle tube,
The medical device according to claim 5 or 6, wherein the second region is disposed proximally of the annular portion. The medical device according to any one of claims 1 to 7, further comprising a stopper that fixes the position of the rod-shaped member in the longitudinal direction relative to the needle tube. When viewed from the distal end side of the needle tube, the needle tube has an opening edge formed by a collection of distal ends of the reduced diameter portions of all half cross sections that are located at different circumferential positions of the needle tube,
The medical device according to claim 8, wherein the rod-shaped member is fixed by the stopper at a first stop position where the rod-shaped member is disposed inside the edge of the opening. When viewed from the distal end side of the needle tube, the needle tube has an opening edge formed by a collection of distal ends of the reduced diameter portions of all half cross sections that are located at different circumferential positions of the needle tube,
The medical device according to claim 8 or 9, wherein the rod-shaped member is fixed by the stopper at a second stop position where the rod-shaped member protrudes from the edge of the opening. The medical device described in any one of claims 1 to 10, wherein the rod-shaped member has, on the outer surface of the distal end thereof, a third region and a fourth region located distal to the third region and having a surface roughness greater than that of the third region. The medical device according to claim 11, wherein the fourth region is disposed over the entire circumference of the rod-shaped member. The medical device according to claim 11 or 12, wherein when the rod-shaped member is moved to the most distal position relative to the needle tube, the proximal end of the fourth region is located distal to the distal end of the needle tube.