puncture needle

Abstract

A puncture needle (10) has: an outer needle (16) having a lumen (16b) passing therethrough in the axial direction; an outer needle hub (18) joined to a base end part of the outer needle (16); an inner needle (20) inserted into the lumen (16b) of the outer needle (16) via the outer needle hub (18); a switching mechanism (23) for switching, by displacing the inner needle (20) in the axial direction, between a first state in which the needle tip (10a) is sharp and a second state in which the needle tip (10a) is blunt; and a rocking mechanism (25) for maintaining the position of the inner needle (20).

Description

[Technical Field]

[0001] The present invention relates to a puncture needle for forming an elongated hole in biological tissue. [Background technology]

[0002] Various medical instruments have been proposed for forming long holes in biological tissue. For example, U.S. Patent No. 10,702,263 describes a suture guide subsystem for penetrating biological tissue and introducing a suture into a site to be sutured within the living body.

[0003] Japanese Utility Model Registration No. 3227041 describes a tunneler for forming a tunnel in a living body and introducing a medium such as an artificial blood vessel into the living body.

[0004] JP 2020-127607 A proposes a placement device for placing an implant that promotes tissue regeneration within biological tissue.

[0005] The above-mentioned instrument has a needle tip formed to be sharp or blunt at the tip of a long, cylindrical puncture member for puncturing biological tissue. Summary of the Invention

[0006] When a puncture needle is to penetrate skin or hard fibrotic tissue, a sharp tip makes the puncture easier and reduces damage to surrounding tissue. On the other hand, when a puncture needle is to penetrate soft tissue such as fatty tissue, a blunt tip is preferable in order to prevent damage to surrounding blood vessels, nerves, etc.

[0007] Therefore, an object of one embodiment is to provide a puncture needle that can suppress damage to biological tissue when puncturing.

[0008] One aspect of the following disclosure is a puncture needle comprising an outer needle having an inner cavity penetrating in the axial direction, an outer needle hub joined to the base end of the outer needle, an inner needle inserted into the inner cavity of the outer needle via the outer needle hub, a switching mechanism that can switch the inner needle between a first state in which the needle tip is sharp and a second state in which the needle tip is blunt by displacing the inner needle in the axial direction, and a locking mechanism that maintains the position of the inner needle.

[0009] According to the puncture needle of the above aspect, damage to biological tissue during puncture can be suppressed. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view of a puncture needle according to a first embodiment. [Figure 2] 2 is a perspective view of the puncture needle of FIG. 1 in a state where the outer needle assembly and inner needle assembly are separated. FIG. [Figure 3] 3A is an enlarged view of the tip of the puncture needle of FIG. 1 in a first state (sharp), and FIG. 3B is an enlarged view of the tip of the puncture needle of FIG. 1 in a second state (blunt). [Figure 4] 4A is a top view of the outer needle hub, and FIG. 4B is a cross-sectional view of the outer needle hub taken along line IVB-IVB in FIG. 4A. [Figure 5] FIG. 5A is a perspective view of the inner needle hub, and FIG. 5B is a perspective view of the needle holder. [Figure 6] 6A is a perspective view of the bottom side of the slider, and FIG. 6B is a cross-sectional view of the inner needle hub taken along line IVB-IVB in FIG. 5A. [Figure 7] FIG. 7A is a cross-sectional view showing the relative positions of the inner needle hub and the outer needle hub in the initial state, and FIG. 7B is an explanatory view showing the operation of protruding the inner needle hub from the initial state. [Figure 8] Figure 8A is a cross-sectional view of the state in which the slider has been advanced toward the tip from the state of Figure 7A to disengage the stopper protrusion from the second recess, and Figure 8B is a cross-sectional view of the state in which the slider has been advanced further toward the tip from the state of Figure 8A. [Figure 9]9A is a cross-sectional view showing a state in which the inner needle hub has moved to the first position and the stopper projection is engaged with the first recess, and FIG. 9B is a side view showing the position of the slider in FIG. 9A. [Figure 10] 10A is a cross-sectional view showing the positional relationship between the inner needle hub and the outer needle hub in the first position, and FIG. 10B is an enlarged cross-sectional view showing the engagement state of the stopper projection and the first recess in FIG. 10A. [Figure 11] FIG. 11A is an explanatory view showing the operation of inserting the puncture needle of FIG. 1 into biological tissue, and FIG. 11B is an explanatory view showing the operation of removing the inner needle after the puncture needle has completed. [Figure 12] FIG. 12 is an explanatory view showing the procedure for attaching an indwelling device to the outer needle assembly of the puncture needle of FIG. [Figure 13] FIG. 13A is an explanatory diagram showing the operation of sending the implant into the target site, and FIG. 13B is an explanatory diagram showing the operation of pulling out the placement device together with the outer needle of the puncture needle, leaving the implant in the biological tissue. [Figure 14] FIG. 14A is an enlarged view of the tip of a puncture needle according to a modified example of the embodiment in a first state (sharp), and FIG. 14B is an enlarged view of the tip of the puncture needle of FIG. 14A in a second state (blunt). [Figure 15] FIG. 15 is an enlarged view showing an example in which a back cut portion is provided in the puncture needle of FIG. 14B. DETAILED DESCRIPTION OF THE INVENTION

[0011] A preferred embodiment of the puncture needle 10 will be described in detail below with reference to the accompanying drawings.

[0012] 1 and 2, the puncture needle 10 according to the embodiment comprises an outer needle assembly 12 and an inner needle assembly 14. The inner needle assembly 14 is arranged so as to be insertable and detachable into the outer needle assembly 12 from the proximal end side of the outer needle assembly 12. The puncture needle 10, with the inner needle assembly 14 attached, is used by puncturing from the skin 100 (see FIG. 11A) of a patient (living body) to a target site in living tissue. After puncturing is complete, the inner needle assembly 14 is removed from the puncture needle 10, and the outer needle assembly 12 is used to introduce an implant 90 (see FIG. 13A) such as an artificial blood vessel or collagen fiber.

[0013] As shown in Figure 2, the outer needle assembly 12 has a long outer needle 16. The outer needle 16 is a cylindrical member made of a metal such as stainless steel, aluminum alloy, or titanium alloy, or a hard resin. The tip 16a of the outer needle 16 is formed approximately perpendicular to the axial direction and is a blunt needle. Inside the outer needle 16, a lumen 16b is formed so as to penetrate the outer needle 16 in the axial direction.

[0014] An outer needle hub 18 is connected to the proximal end of the outer needle 16. The outer needle hub 18 is a tubular member made of a resin such as polycarbonate, and is formed with an outer diameter that allows the user to easily grip and manipulate it by hand. A hollow portion 18a extending in the axial direction is formed inside the outer needle hub 18. The distal end side of the hollow portion 18a communicates with the inner cavity 16b of the outer needle 16, and the proximal end side of the hollow portion 18a opens at the proximal end of the outer needle hub 18. The hollow portion 18a extends in the axial direction and guides the sliding movement of the inner needle hub 22, which will be described later. Details of the structure of the outer needle hub 18 will be described later.

[0015] On the other hand, the inner needle assembly 14 has a long inner needle 20. The inner needle 20 is a long tubular member and is formed from a metal such as stainless steel. The inner needle 20 is formed with an outer diameter smaller than the lumen 16b of the outer needle 16 and is insertable into the lumen 16b. The inner needle 20 is a hollow needle with a lumen 20b formed therein. The inner needle 20 may also be a solid needle with a solid interior. The tip 20a of the inner needle 20 is formed to be sharp.

[0016] As shown in Fig. 3A, the distal end portion 20a has a blade surface that is cut out obliquely with respect to the axial direction, and a sharp cutting edge is formed at the tip of the blade surface. The inner needle 20 is formed longer than the outer needle 16. When the inner needle assembly 14 of Fig. 1 is pushed toward the distal end side of the outer needle assembly 12, the distal end portion 20a of the inner needle 20 protrudes from the distal end portion 16a of the outer needle 16, as shown in Fig. 3A, and the needle tip 10a of the puncture needle 10 is in a sharp first state. When the inner needle assembly 14 of Fig. 1 is moved toward the proximal end side of the outer needle assembly 12, the distal end portion 20a of the inner needle 20 is retracted inside the distal end portion 16a of the outer needle 16, as shown in Fig. 3B, and the needle tip 10a of the puncture needle 10 is in a blunt second state.

[0017] As shown in Figure 2, an inner needle hub 22 is provided at the proximal end of the inner needle 20 in order to operate the inner needle assembly 14. The inner needle hub 22 comprises a needle holding portion 24 joined to the inner needle 20, and a slider 26 attached to the needle holding portion 24. The needle holding portion 24 of the inner needle hub 22 is disposed inside the hollow portion 18a of the outer needle hub 18, and slides axially within the hollow portion 18a.

[0018] The outer needle hub 18 and the inner needle hub 22 constitute a switching mechanism 23 that switches the needle tip 10a of the puncture needle 10 between a sharp first state and a blunt second state. The switching mechanism 23 will be described in detail below.

[0019] As shown in Figures 4A and 4B, a connecting portion 28 that holds the outer needle 16 is formed near the tip of the outer needle hub 18. The connecting portion 28 is formed in a funnel shape whose outer dimensions gradually increase from the tip side to the base end side. On the base end side of the connecting portion 28, an outer needle hub body 30 that is formed in a tubular shape with a rectangular cross section is formed. The outer needle hub body 30 is formed to be elongated in the axial direction. Inside the outer needle hub body 30, a hollow portion 18a extends in the axial direction while maintaining a constant width.

[0020] As shown in Fig. 4A, a guide groove 32 is formed in the upper end portion 30a of the outer needle hub body 30. As shown in Fig. 4A, the guide groove 32 is formed penetrating the upper end portion 30a of the outer needle hub body 30 in the thickness direction (the up-down direction, the direction perpendicular to the paper surface in Fig. 4A), and the hollow portion 18a opens to the upper end portion 30a through the guide groove 32. As shown in Fig. 4B, the guide groove 32 extends in the axial direction, all the way to the base end of the outer needle hub body 30. Stopper protrusions 60, 62 of the needle holding portion 24, which will be described later, slide against and contact the guide groove 32.

[0021] The guide groove 32 is provided with a first recess 34, a second recess 36, a first protrusion 38, and a second protrusion 40. These structures constitute part of a locking mechanism 25 that positions the needle tip 10a in the first state of FIG. 3A or the second state of FIG. 3B. The first recess 34 is formed so as to be recessed outward from the guide groove 32, and a pair of first recesses 34 are provided on both sides of the guide groove 32. The first recess 34 is formed in a semicircular shape, and steps 34a perpendicular to the axial direction are formed at the ends on the base end and tip end sides to fix the needle holding part 24 (see FIG. 10B).

[0022] The second recess 36 is formed closer to the base end than the first recess 34. The second recess 36 is formed in a semicircular shape like the first recess 34, and a pair of second recesses 36 are provided on both sides of the guide groove 32. Step portions 36a perpendicular to the axial direction are formed at the base end and tip end of the second recess 36. The first recess 34, the second recess 36, and stopper protrusions 60, 62 (see FIG. 5B), which will be described later, form a locking mechanism 25 that fixes the first state and the second state of the puncture needle 10.

[0023] The guide groove 32 between the first recess 34 and the second recess 36 is provided with a pair of first protrusions 38 that protrude inward in the width direction from both side portions of the guide groove 32. The first protrusions 38 have an apex 38a formed at a midpoint in the axial direction between the first recess 34 and the second recess 36. An inclined surface 38b is formed between the apex 38a and the first recess 34, such that the width of the guide groove 32 increases as the distance from the apex 38a approaches the first recess 34. Furthermore, an inclined surface 38c is formed between the apex 38a and the second recess 36, such that the width of the guide groove 32 increases as the distance from the apex 38a approaches the second recess 36.

[0024] The guide groove 32 on the base end side of the second recess 36 is formed with second protrusions 40 that protrude inward in the width direction from both side portions of the guide groove 32. The second protrusions 40 have an apex 40a. Between the apex 40a and the second recess 36, an inclined surface 40b is formed that is inclined so that the width of the guide groove 32 increases as it approaches the second recess 36 from the apex 40a.

[0025] As shown in Figures 2 and 4B, a pair of guide plates 42 are provided on the upper part of the outer needle hub main body 30, protruding upward. The guide plates 42 are provided near both side parts of the outer needle hub main body 30, sandwiching the guide groove 32 in the width direction. The guide plates 42 extend to the base end in the axial direction. The slider 26 of the inner needle hub 22 is disposed between the guide plates 42. The guide plates 42 guide the axial movement of the slider 26. A bridge portion 44 is provided at the base end of the guide plates 42, connecting the guide plates 42 on both sides. The bridge portion 44 protrudes upward, and the inner needle hub 22 can be inserted from the base end side of the outer needle hub main body 30 through a gap at the bottom of the bridge portion.

[0026] Next, we will explain the inner needle hub 22, which constitutes another part of the switching mechanism 23. The inner needle hub 22 is a member joined to the base end of the inner needle 20, and is made of a hard resin such as polycarbonate. As shown in FIG. 5A , the inner needle hub 22 has a needle holding portion 24 that can be inserted into the guide groove 32 of the outer needle hub body 30, and a slider 26 provided on the upper part of the needle holding portion 24.

[0027] The needle holding part 24 is a member connected to the inner needle 20. The needle holding part 24 has an inner needle connecting part 46 and a needle holding main body part 47. The inner needle connecting part 46, to which the inner needle 20 is connected, is formed on the distal side of the needle holding part 24. The inner needle connecting part 46 is formed in a tapered shape so that its width decreases towards the distal end. On the proximal side of the inner needle connecting part 46, a needle holding main body part 47, which extends linearly with a constant width towards the proximal side, is formed integrally with the inner needle connecting part 46. The width of the needle holding main body part 47 is formed to be approximately the same dimension as the width of the hollow part 18a of the outer needle hub body 30, and is capable of sliding axially within the hollow part 18a.

[0028] As shown in FIG. 5B, the needle holder 24 has a rectangular cross section, and a first arm 50 and a second arm 52 protrude upward from its upper end 24a. The first arm 50 and the second arm 52 protrude upward like a wall above the needle holder 24 and are separated from the needle holder 24 by a notch 54. The first arm 50 is joined to the needle holder 24 via a support 56 provided on the distal end of the needle holder 24 and extends toward the proximal end. The first arm 50 is inclined so as to approach one side portion 24b as it moves from the support 56 toward the proximal end. A stopper projection 60 protruding laterally is formed at the proximal end of the first arm 50.

[0029] The second arm 52 is joined to the needle holder 24 via a support 58 provided on the base end side of the needle holder 24. The second arm 52 extends from the support 58 in the center of the width of the needle holder 24 towards the tip side. The second arm 52 is inclined so as to approach the other side portion 24c as it moves from the support 58 towards the tip side. A stopper projection 62 that projects laterally is formed at the tip of the second arm 52.

[0030] The stopper protrusion 60 of the first arm 50 and the stopper protrusion 62 of the second arm 52 are formed at the same position in the axial direction of the needle holding part 24. The widthwise separation distance between the stopper protrusion 60 of the first arm 50 and the stopper protrusion 62 of the second arm 52 is formed to be larger than the widthwise gap of the guide groove 32 of the outer needle hub body 30. Therefore, when the needle holding part 24 is inserted into the outer needle hub body 30, the stopper protrusions 60 and 62 abut against the guide groove 32. The stopper protrusion 60 is pressed against the guide groove 32 by the elastic restoring force of the first arm 50, and the stopper protrusion 62 is pressed against the guide groove 32 by the elastic restoring force of the second arm 52.

[0031] An axially elongated rectangular mounting hole 64 is formed in the center (between the first arm 50 and the second arm 52) of the upper end 24a of the needle holder 24. A mounting protrusion 66 of the slider 26 shown in Figure 6A is inserted into the mounting hole 64.

[0032] As shown in Fig. 1, the slider 26 is a sliding member disposed between a pair of guide plates 42 on the upper part of the outer needle hub body 30, and is displaced when subjected to an operating force from the user. The slider 26 is disposed between the guide plates 42. As shown in Fig. 5A, an anti-slip rib structure 70 is formed on the upper part of the slider 26.

[0033] As shown in Fig. 6A, a pair of side walls 72 protrude from both sides of the bottom 26b of the slider 26. A release protrusion 74 that abuts against the stopper protrusions 60, 62 (see Fig. 5B) is formed on the side walls 72 and protrudes inward in the width direction. Each release protrusion 74 has inclined surfaces 76a, 76b, and is provided with a tapered portion 76 that accommodates the stopper protrusions 60, 62. In addition, an attachment protrusion 66 protrudes from the center of the bottom 26b of the slider 26.

[0034] As shown in Figure 6B, the mounting protrusion 66 is a protrusion that is inserted into the mounting hole 64 of the needle holder 24. As shown in Figure 6A, an anchor portion 68 that protrudes wider than the mounting hole 64 is formed at the tip of the mounting protrusion 66 to prevent it from falling out of the mounting hole 64. As shown in Figure 6B, the mounting protrusion 66 of the slider 26 is formed to have an axial length that is shorter than the mounting hole 64 of the needle holder 24, and the slider 26 is provided with play that allows it to be displaced axially within a predetermined range relative to the needle holder 24 when attached to the needle holder 24. When this play is used to move the slider 26 relative to the needle holder 24, the inclined surfaces 76a, 76b of the release protrusion 74 of Figure 6A can displace the stopper protrusions 60, 62 of the needle holder 24 inward, releasing them from their engagement with the first recess 34 (or second recess 36) of the guide groove 32.

[0035] The operation of the puncture needle 10 of this embodiment will be described below together with how to use it.

[0036] The puncture needle 10 is provided in a state in which the inner needle assembly 14 is inserted into the outer needle assembly 12, as shown in Figure 1. However, in order to prevent accidental punctures with the needle tip 10a during storage and transportation, in the initial state, as shown in Figure 3B, the tip portion 20a of the inner needle 20 is stored on the proximal side of the tip portion 16a of the outer needle 16 (blunt needle), in a second state.

[0037] 7A, the stopper protrusions 60 and 62 of the needle holding part 24 are engaged with the second recesses 36 of the guide groove 32 of the outer needle hub body 30. The stopper protrusion 60 is pressed against one of the second recesses 36 by the resilient force of the first arm 50, and the stopper protrusion 62 is pressed against the other of the second recesses 36 by the resilient force of the second arm 52. Therefore, the axial position of the needle holding part 24 is fixed at the second position by the stopper protrusions 60, 62 and the second recesses 36. That is, the stopper protrusions 60, 62, the first arm 50, the second arm 52, and the second recesses 36 constitute the locking mechanism 25 at the second position.

[0038] The user first performs an operation to project the tip portion 20a of the inner needle 20 from the tip portion 16a of the outer needle 16. This operation is performed by the user holding the outer needle hub body 30 in one hand, placing their thumb on the slider 26, and moving the slider 26 forward toward the tip, as shown in Figure 7B.

[0039] As shown in Figure 8A, when the user advances slider 26 toward the tip, the axial play between slider 26 and needle holder 24 causes slider 26 to displace toward the tip relative to needle holder 24. This displaces tapered portion 76 of release projection 74 toward the tip, and inclined surface 76b on the rear end abuts stopper projections 60, 62. As slider 26 advances further, stopper projections 60, 62 displace inward in the width direction along inclined surface 76b. As a result, the engagement between stopper projections 60, 62 and second recess 36 is released. This allows needle holder 24 to be displaced axially.

[0040] As shown in FIG. 8B , the distal edge of the mounting projection 66 of the slider 26 abuts against the distal end of the mounting hole 64, and the needle holder 24 advances toward the distal end together with the slider 26. The stopper projections 60, 62 are displaced in the axial direction while sliding along the inclined surfaces 38b, 38c of the first projection 38 of the guide groove 32. If the thumb is released from the slider 26 before the slider 26 passes the apex 38a of the first projection 38, the stopper projection 60 biased by the first arm 50 and the stopper projection 62 biased by the second arm 52 slide along the inclined surface 38c toward the second recess 36, causing the needle holder 24 to retract toward the proximal end. The stopper projections 60, 62 then engage with the second recess 36, stopping the needle holder 24.

[0041] As shown in FIG. 9A, when the needle holder 24 is advanced toward the distal end via the slider 26, the stopper projections 60, 62 move over the apex 38a of the first convex portion 38 of the guide groove 32 toward the distal end and displace to the first position where they engage with the first recess 34. Subsequently, when the stopper projections 60, 62 engage with the first recess 34, vibration (impact) occurs, and this vibration is transmitted to the user's hand as a clicking sensation. The user recognizes from the clicking sensation at their fingertips that the needle tip 10a has switched to the first state (sharp). Therefore, as shown in FIG. 3A, the sharp tip portion 20a protrudes from the distal end portion 16a of the outer needle 16. As shown in FIGS. 9A and 9B, in the first position, the slider 26 abuts against the distal end side of the guide groove 32 of the outer needle hub body 30 and stops.

[0042] When the stopper projections 60, 62 move over the top 38a of the first convex portion 38 toward the inclined surface 38b, the resilient forces of the first arm 50 and the second arm 52 act, generating a thrust force on the slider 26 and the needle holder 24 toward the first recess 34. Therefore, even if the user releases his or her thumb from the slider 26, the needle holder 24 will spontaneously displace toward the tip until the stopper projections 60, 62 engage with the first recess 34.

[0043] As shown in Fig. 10A, in the first position, the stopper projections 60, 62 are engaged with the first recess 34 while being pressed by the elastic forces of the first arm 50 and the second arm 52. As shown enlarged in Fig. 10B, flat surfaces perpendicular to the axial direction are provided at the distal and proximal ends of the first recess 34, and further, flat surfaces perpendicular to the axial direction are formed on the proximal ends of the stopper projections 60, 62. Therefore, even when a load acts on the inner needle 20 to displace it proximally, such as when the inner needle 20 is punctured into the skin 100, the stopper projections 60, 62 will not come off the first recess 34. Therefore, even when an axial load acts on the inner needle 20, the needle holding part 24 will not be displaced from the first position and will be held in the first position. In the first position, the stopper projections 60, 62, the first arm 50, the second arm 52, and the first recess 34 constitute a locking mechanism 25.

[0044] The user then removes his or her thumb from the slider 26 and inserts the needle tip 10a of the puncture needle 10 into the skin 100 of the patient (living body) as shown in FIG. 11A. After puncturing the subcutaneous tissue, the user operates the slider 26 to switch the needle tip 10a between the first state (sharp) and the second state (blunt). That is, when the slider 26 is retracted toward the base end, the release protrusion 74 of the slider 26 moves toward the base end from the state shown in FIG. 10A, and the inclined surface 76a on the tip side of the release protrusion 74 abuts against the stopper protrusions 60, 62. Then, as the inclined surface 76a moves toward the base end, the stopper protrusions 60, 62 are pushed back inward, and the engagement of the stopper protrusions 60, 62 with the first recess 34 is released, allowing the needle holding portion 24 to move toward the base end.

[0045] By sliding the slider 26 further toward the proximal end, the needle holding portion 24 moves toward the proximal end and stops at the second position where the stopper protrusions 60, 62 engage with the second recess 36, as shown in FIG. 7A. As a result, as shown in FIG. 3B, the distal end 20a of the inner needle 20 is retracted toward the proximal end of the distal end 16a of the outer needle 16, and the needle tip 10a of the puncture needle 10 switches to the second state (blunt). When the stopper protrusions 60, 62 engage with the second recess 36, a slight vibration is transmitted to the user's hand as a clicking sensation. This allows the user to recognize that the needle tip 10a of the puncture needle 10 has switched to the second state (blunt) even if the user cannot see the needle tip 10a.

[0046] In addition, while the needle holder 24 is being moved from the first position to the second position, the stopper protrusions 60, 62 are pressed into contact with the inclined surfaces 38b, 38c of the first convex portion 38 of the guide groove 32. Therefore, a thrust force toward the first position acts on the needle holder 24 until the stopper protrusions 60, 62 pass the apex 38a. Furthermore, after the stopper protrusions 60, 62 pass the apex 38a and move toward the base end, a thrust force toward the second position acts on the needle holder 24. Therefore, because the needle holder 24 stops at only the first position or the second position, the user can easily check whether the needle tip 10a of the puncture needle 10 is sharp or blunt, even when the state of the needle tip 10a of the puncture needle 10 cannot be visually confirmed.

[0047] The user advances the puncture needle 10 to the target site in the living tissue while switching the needle tip 10a of the puncture needle 10 between a first state (sharp) and a second state (blunt).

[0048] As shown in FIG. 11B, after the needle tip 10a of the puncture needle 10 has reached the target position, the user pulls out the inner needle assembly 14 from the outer needle assembly 12.

[0049] Thereafter, as shown in FIG. 12, the user inserts the placement device 80 holding the implant 90 (for example, collagen fibers or the like) at the tip from the proximal end of the outer needle assembly 12.

[0050] As shown in Fig. 13A, the user projects the tip of the retention device 80 from the tip portion 16a of the outer needle 16 of the outer needle assembly 12, and then, as shown in Fig. 13B, pulls out the outer needle assembly 12 together with the retention device 80 from the skin 100 of the living body. This completes the implantation of the implant 90 into the living tissue.

[0051] (Variation) Below, we will explain modified examples of the puncture needle 10 of this embodiment. As shown in Figures 14A and 14B, in the needle tip 10a according to the modified example, the tip 20a of the inner needle 20 is a blunt needle formed into a spherical shape, and the tip 16a of the outer needle 16 has a sharp cutting edge that is notched obliquely relative to the axial direction.

[0052] In this modified example, the state in which the tip 20a of the inner needle 20 protrudes further than the tip 16a of the outer needle 16 as shown in Figure 14B is the second state (blunt), and the state in which the tip 20a of the inner needle 20 is retracted further toward the base end than the tip 16a of the outer needle 16 as shown in Figure 14A is the first state (sharp).

[0053] 14B, a gap 16c is created between the inner needle 20 and the cutting edge of the tip 16a of the outer needle 16, and if a blood vessel, nerve, or the like enters this space, there is a risk that the sharp cutting edge will damage these tissues. Therefore, in this modified example, as shown in Figure 15, a back cut portion 16d may be provided near the cutting edge of the tip 16a of the outer needle 16, thereby minimizing the gap 16c (see Figure 14B).

[0054] The puncture needle 10 of this embodiment has the following advantages.

[0055] The puncture needle 10 of this embodiment comprises an outer needle 16 having an inner cavity 16b penetrating in the axial direction, an outer needle hub 18 joined to the base end of the outer needle 16, an inner needle 20 inserted into the inner cavity 16b of the outer needle 16 via the outer needle hub 18, a switching mechanism 23 that can displace the inner needle 20 in the axial direction to switch between a first state in which the needle tip 10a is sharp and a second state in which the needle tip 10a is blunt, and a locking mechanism 25 that maintains the position of the inner needle 20.

[0056] According to the above-described puncture needle 10, the needle tip 10a can be switched between a sharp first state and a blunt second state. This allows the needle to be advanced through biological tissue while preventing damage to blood vessels, nerves, etc. Furthermore, the provision of the locking mechanism 25 prevents the needle tip 10a from switching from the first state to the second state during puncture, allowing the user to concentrate on the puncture operation.

[0057] In the above-described puncture needle 10, the tip 20a of the inner needle 20 may be sharp and the tip 16a of the outer needle 16 may be blunt. In this case, the state in which the tip 20a of the inner needle 20 protrudes beyond the tip 16a of the outer needle 16 is the sharp first state.

[0058] In the above-described puncture needle 10, the tip 16a of the outer needle 16 may be sharp, and the tip 20a of the inner needle 20 may be blunt. In this case, the state in which the tip 20a of the inner needle 20 is retracted further toward the base end than the tip 16a of the outer needle 16 is the first sharp state. In this case, a back cut portion 16d may be provided on the tip 16a of the outer needle 16. This can prevent damage to tissues such as blood vessels and nerves.

[0059] The above-mentioned puncture needle 10 may further have an inner needle hub 22 that is provided at the base end of the inner needle 20 and inserted into the outer needle hub 18, and the switching mechanism 23 may have a guide groove 32 that is provided on the outer needle hub 18 and guides the inner needle hub 22 in the axial direction, a first recess 34 that is provided in the guide groove 32 and positions the inner needle hub 22 at a first position, a second recess 36 that is provided on the base end side of the first recess 34 and positions the inner needle hub 22 at a second position, and stopper protrusions 60, 62 that are provided on the inner needle hub 22 and protrude from the inner needle hub 22 towards the guide groove 32 while being elastically biased, and engage with the first recess 34 and the second recess 36.

[0060] According to this configuration, the needle tip 10a can be switched between the first state and the second state by engaging the stopper protrusions 60, 62 with the first recess 34 or the second recess 36. Furthermore, the user can recognize the switch between the first state and the second state without having to look at their hand because of the clicking sensation felt when the stopper protrusions 60, 62 engage with the first recess 34 or the second recess 36, making it easier to handle the puncture needle 10.

[0061] In the above-described puncture needle 10, the inner needle hub 22 includes a slider 26 provided on the inner needle hub 22, and the slider 26 may be configured to retract the stopper protrusions 60, 62 inward, thereby releasing the engagement between the stopper protrusions 60, 62 and the first recess 34 or the second recess 36. According to this configuration, the user can easily move the inner needle hub 22 by operating the slider 26.

[0062] In the above-described puncture needle 10, the first recess 34 and the second recess 36 may be provided with stepped portions 34a, 36a that prevent the stopper projections 60, 62 from coming off. According to this configuration, even if an axial load acts on the inner needle 20, movement of the inner needle hub 22 can be prevented, and the first state or the second state can be maintained.

[0063] In the above-described puncture needle 10, the guide groove 32 may be provided with inclined surfaces 38b, 38c, 40b that guide the stopper protrusions 60, 62 into the first recess 34 or the second recess 36. With this configuration, the inner needle hub 22 is spontaneously displaced to the first position or the second position, and therefore it is possible to prevent the inner needle hub 22 from stopping with the needle tip 10a of the puncture needle 10 in an unknown state midway between the first state or the second state, thereby improving the handleability of the puncture needle 10.

[0064] Although the present invention has been described above by citing preferred embodiments, it goes without saying that the present invention is not limited to the above embodiments, and various modifications are possible within the scope of the present invention.

Claims

1. an outer needle having an inner lumen passing through in the axial direction; an outer needle hub joined to the base end of the outer needle; an inner needle inserted into the inner cavity of the outer needle via the outer needle hub; a switching mechanism that can switch the inner needle between a first state in which the needle tip is sharp and a second state in which the needle tip is blunt by displacing the inner needle in an axial direction; a locking mechanism for maintaining the position of the inner needle; an inner needle hub that is provided at the proximal end of the inner needle and is inserted into the outer needle hub, and the switching mechanism comprises: a guide groove provided in the outer needle hub to guide the inner needle hub in the axial direction; a first recess provided in the guide groove for positioning the inner needle hub at a first position, and a second recess provided on the proximal side of the first recess for positioning the inner needle hub at a second position; a stopper projection that is provided on the inner needle hub and projects from the inner needle hub toward the guide groove while being elastically biased, and that engages with the first recess and the second recess, The puncture needle has a slider provided on the inner needle hub, and the slider pulls the stopper protrusion inward to release the engagement between the stopper protrusion and the first recess or the second recess.

2. 2. The puncture needle according to claim 1, wherein the tip of the inner needle is sharp and the tip of the outer needle is blunt.

3. 2. The puncture needle according to claim 1, wherein the tip of the outer needle is sharp and the tip of the inner needle is blunt.

4. The puncture needle according to claim 3, wherein a back cut portion is formed at the tip of the outer needle.

5. The puncture needle according to claim 1 , wherein the first recess and the second recess are provided with a step portion that prevents the stopper projection from coming off.

6. 6. The puncture needle according to claim 1, wherein the guide groove is provided with an inclined surface that guides the stopper projection into the first recess or the second recess.

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