Tissue sampling needle

Abstract

[Problem] To provide a tissue sampling needle configured to prevent the application of load on the cells of biological tissue at a tapered portion. [Solution] A tissue sampling needle 100 has a needle body section 110 with a lumen 115 formed therein. The needle body section comprises: a distal end part 120 which includes a needle tip 121 that is formed at the leading end and is capable of penetrating biological tissues, the distal end part extending along the axial direction and having a substantially constant inner diameter di1; a proximal end part 130 which is positioned closer to the proximal side than the distal end part is and extends along the axial direction with a substantially constant inner diameter di2; and a tapered part 140 which is located between the distal end part and the proximal end part, and has a inner diameter di3 that increases from the distal side to the proximal side. The inner diameter of the distal end part is 0.5 mm or more and the average taper angle of the tapered part is 5° or less.

Description

tissue collection needle

[0001] The present invention relates to a tissue collection needle.

[0002] BACKGROUND ART Conventionally, a procedure has been performed in which a tissue sampling needle is used to sample biological tissue and various cells contained in the biological tissue.

[0003] Examples of the above-mentioned procedures include a procedure for transvaginally extracting eggs from the ovaries in infertility treatment, and a procedure for diagnosing a lesion by percutaneously aspirating and observing cells from the lesion.

[0004] It is desirable for tissue collection needles to have a smaller outer diameter to reduce the pain experienced by the patient during puncture. However, if the inner diameter (lumen diameter) of the tissue collection needle is also reduced as the outer diameter is reduced, excessive stress is placed on the cells of the collected biological tissue as they move through the lumen. On the other hand, if the thickness of the tissue collection needle is reduced in order to maintain the inner diameter while reducing the outer diameter, the bending strength of the tissue collection needle is reduced, making it more susceptible to bending and other problems during procedures using the tissue collection needle, reducing operability.

[0005] In order to solve the above problems, it is conceivable to adopt a tapered needle, such as the tissue collection needle described in Patent Document 1, in which the outer and inner diameters at the tip end are small, the outer and inner diameters at the base end are larger than those at the tip end, and a tapered section is provided between the tip end and the base end in which the outer and inner diameters gradually increase from the tip end to the base end. By configuring the tissue collection needle as a tapered needle, the pain felt by the patient due to the thinned diameter tip end can be reduced, while the large diameter base end can prevent the tissue collection needle from bending.

[0006] Special table number 2010-534332

[0007] However, if the tapered portion has a large taper angle and the inner diameter of the tissue sampling needle changes abruptly at the tapered portion, the following problems may occur.

[0008] If the taper angle of the tapered section located between the distal and proximal ends of the tissue sampling needle is extremely large and a step-like section is formed in the lumen, turbulence will occur in the flow of biological tissue from the distal end to the proximal end, resulting in excessive stress being placed on the cells of the biological tissue.

[0009] The present invention is intended to solve the above problems, and has an object to provide a tissue collection needle that can prevent stress from being applied to cells at the tapered portion.

[0010] The above object of the present invention can be achieved by the following means.

[0011] (1) A tissue collection needle having a needle body portion with a lumen formed therein, the needle body portion having: a distal end portion having a needle tip formed at its distal end capable of being inserted into biological tissue and extending with a substantially constant inner diameter along the axial direction; a proximal end portion located proximal to the distal end portion and extending with a substantially constant inner diameter along the axial direction; and a tapered portion located between the distal end portion and the proximal end portion, the inner diameter of which increases from the distal end side to the proximal end side, wherein the inner diameter of the distal end portion is 0.5 mm or more, and the average taper angle of the tapered portion is 5° or less.

[0012] (2) The tissue sampling needle according to (1), wherein the inner diameter of the base end is 1.0 mm or more.

[0013] (3) The tissue collection needle according to (1) or (2), wherein the tip portion extends along the axial direction with a substantially constant outer diameter of 1.1 mm or less, and the base portion extends along the axial direction with a substantially constant outer diameter of 1.2 mm or more.

[0014] (4) The tissue collection needle according to any one of (1) to (3), wherein the axial length of the tip portion is 10 mm or more, the axial length of the tapered portion is 5.7 mm or more, and the axial length of the base end portion is 10 mm or more.

[0015] (5) The tissue sampling needle according to any one of (1) to (4), wherein the tapered portion has a first tapered portion extending from the base end of the tip portion toward the base end side, and a second tapered portion extending from the base end of the first tapered portion toward the base end side, and the average taper angle of the first tapered portion is larger than the average taper angle of the second tapered portion.

[0016] (6) The tissue sampling needle according to any one of (1) to (5), wherein the tapered portion extends linearly or curvedly from the distal end side to the proximal end side.

[0017] According to the above-mentioned tissue collection needle, the inner diameter of the tip is 0.5 mm or more, and the average taper angle of the tapered portion is 5° or less, so that stress is prevented from being placed on the cells of the biological tissue when the collected biological tissue moves within the tip and through the tapered portion.

[0018] FIG. 3 is a diagram showing a tissue sampling needle according to an embodiment of the present invention. FIG. 4 is a cross-sectional view along the axial direction of the needle main body. FIG. 5 is a cross-sectional view of the needle main body along arrow 3-3 shown in FIG. 2. FIG. 6 is a cross-sectional view of the needle main body along arrow 4-4 shown in FIG. 2. FIG. 7 is a cross-sectional view of the needle main body along arrow 5-5 shown in FIG. 2. FIG. 8 is an enlarged view of a portion of the needle main body of an example and a comparative example. FIG. 9 is a graph showing the results (simulation results of pressure loss) of the example and the comparative example. FIG. 10 is a graph showing the results (simulation results of shear stress) of the example and the comparative example. FIG. 11 is an enlarged view of a portion of the needle main body according to modified example 1. FIG. 12 is an enlarged view of a portion of the needle main body according to modified example 2.

[0019] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following description does not limit the technical scope or meaning of terms described in the claims. Also, the dimensional proportions in the drawings are exaggerated for the convenience of explanation and may differ from the actual proportions.

[0020] A tissue sampling needle 100 according to an embodiment of the present invention will be described below with reference to FIGS.

[0021] Fig. 1 shows a tissue sampling needle 100 according to an embodiment and a tissue sampling device 10 including the tissue sampling needle 100 as a constituent member. Fig. 2 is a partial cross-sectional view taken along the axial direction of the needle main body 110, and Figs. 3 to 5 are cross-sectional views (cross-sectional views perpendicular to the axis) of the needle main body 110 at the positions indicated by arrows 3-3, 4-4, and 5-5 shown in Fig. 2.

[0022] In the description of this specification, the direction in which the needle body 110 extends is defined as the "axial direction," and is indicated by the arrows X1-X2 in the drawings. In addition, in the tissue sampling needle 100, the side that is inserted into the living body (the side indicated by the arrow X1) is defined as the distal end, and the side that is operated by the hand and located opposite the distal end (the side indicated by the arrow X2) is defined as the proximal end.

[0023] <Tissue Harvesting Device 10 > As shown in FIG. 1, the tissue harvesting device 10 includes a tissue harvesting needle 100 and a suction unit 200 .

[0024] The tissue sampling needle 100 includes a needle body 110 that is inserted into biological tissue. A lumen 115 (see FIG. 2) is formed inside the needle body 110, and biological tissue cells can be collected via the lumen 115. A hub portion 160 that can be connected via a tube or the like to a suction portion 200 that generates suction pressure (negative pressure) within the lumen 115 when collecting tissue is disposed at the base end portion 130 of the tissue sampling needle 100.

[0025] The suction section 200 used in the tissue harvesting device 10 can be configured with a known pump mechanism used for harvesting biological tissue, for example.

[0026] <Tissue sampling needle 100> As shown in Figures 1 and 2, the tissue sampling needle 100 comprises a needle body 110 having a lumen 115 formed therein, and a hub portion 160 connected to the base end of the needle body 110.

[0027] The tissue sampling needle 100 is configured as a medical instrument used to aspirate and collect cells through a tip opening 121a formed in the needle tip 121 of the tissue sampling needle 100. When collecting cells, the needle tip 121 of the needle body 110 is punctured into biological tissue of a predetermined biological organ. Furthermore, by operating the suction unit 200 while the needle tip 121 is punctured into the biological tissue, cells of the biological tissue can be extracted to the outside of the living body through the lumen 115 of the tissue sampling needle 100.

[0028] There are no particular limitations on the uses of the tissue collection needle 100 according to this embodiment, but it can be used, for example, in procedures for transvaginally collecting eggs from the ovaries in infertility treatment, and in procedures for diagnosing lesions by percutaneously aspirating and observing cells from the lesion.

[0029] <Needle main body 110> As shown in Figures 1 to 5, the needle main body 110 has a tip 121 formed at its distal end that can be inserted into biological tissue, and a distal end 120 that extends along the axial direction with a substantially constant inner diameter di1, a proximal end 130 that is located closer to the proximal end than the distal end 120 and extends along the axial direction with a substantially constant inner diameter di2, and a tapered section 140 that is located between the distal end 120 and the proximal end 130 and has an inner diameter di3 that increases from the distal end side to the proximal end side.

[0030] The needle tip 121 can be configured as, for example, a known bevel needle. However, the needle tip 121 is not particularly limited in terms of its specific shape or structure, as long as it can puncture the biological organ to be punctured.

[0031] The needle tip 121 is formed with a tip opening 121a that communicates with the lumen 115. When a certain range on the tip side including the needle tip 121 of the tissue sampling needle 100 is inserted into a biological organ, the tissue sampling needle 100 can draw (suck) biological tissue into the lumen 115 via the tip opening 121a by operating the suction unit 200.

[0032] The distal end portion 120 extends linearly over a certain range from the distal end where the needle tip 121 is located to the proximal end side. The outer diameter Do1 of the distal end portion 120 can be configured to be approximately constant in the axial direction.

[0033] The tapered portion 140 starts from a tapered portion tip 141 located at the base end of the distal end 120 and extends linearly to a tapered portion base end 142 located at the tip of the proximal end 130 so that the inner diameter di3 increases and decreases. The outer diameter Do3 of the tapered portion 140 is configured to increase from the distal end side to the base end side at approximately the same rate as the inner diameter di3 of the tapered portion 140.

[0034] The base end portion 130 extends linearly over a certain range on the base end side from the tapered portion base end 142. The outside diameter Do1 of the base end portion 130 can be configured to be approximately constant in the axial direction.

[0035] The lumen 115 is continuously connected along each of the distal end portion 120, the tapered portion 140, and the proximal end portion 130. The central axis c1 of the needle body 110 passes through the centers of the portions 120, 130, and 140 (the centers of the cross sections perpendicular to the axis).

[0036] There are no particular restrictions on the material that constitutes the needle main body 110, but for example, metal materials such as stainless steel, aluminum, aluminum alloys, titanium, titanium alloys, etc., and resin materials such as polyethylene, polypropylene, polymethyl methacrylate, polycarbonate, polyamide, polyethylene terephthalate, etc. can be used.

[0037] Examples of dimensions of each part of the needle main body 110 will be described below.

[0038] The inner diameter di1 of the tip portion 120 can be set to 0.5 mm or more, and the average taper angle of the tapered portion 140 can be set to 5° or less.

[0039] The needle main body 110 is configured such that the inner diameter di1 of the tip portion 120 is 0.5 mm or more, thereby reducing pressure loss at the tip portion 120 when suction pressure is generated within the lumen 115 of the needle main body 110. This reduces the suction pressure generated to move collected cells toward the base end within the lumen 115. This reduces the load on cells when the biological tissue moves within the tip portion 120.

[0040] From the viewpoint of reducing the pressure loss as described above, the inner diameter di1 of the tip portion 120 is preferably 0.6 mm or more, and more preferably 0.7 mm or more.

[0041] The needle main body 110 is configured such that the average taper angle of the tapered portion 140 is 5° or less, so that the inner diameter di3 of the tapered portion 140 gradually increases from the tapered portion tip 141 to the tapered portion base end 142. This prevents the flow of fluid (fluid containing biological tissue generated by suction by the suction portion 200) flowing through the tapered portion 140 from becoming significantly turbulent in the tapered portion 140. Therefore, the needle main body 110 can reduce the load on the collected cells as they flow through the tapered portion 140.

[0042] From the viewpoint of suppressing the generation of turbulence as described above, the average taper angle of the tapered portion 140 is preferably 4° or less, and more preferably 3° or less.

[0043] In this embodiment, the "average taper angle" can be defined as twice the angle (see θ in Figure 2) between the central axis c1 and a line representing the rate of change of the inner radius calculated by (inner diameter [mm] of tapered portion base end 142 - inner diameter [mm] of tapered portion tip 141) / 2 / axial length L3 [mm] of tapered portion 140 (linear length in the axial direction between tapered portion tip 141 and tapered portion base end 142).

[0044] The inner diameter di2 (see FIG. 4) of the base end portion 130 can be configured to be 1.0 mm or more. By configuring the inner diameter di2 of the base end portion 130 to be 1.0 mm or more, it is possible to reduce pressure loss at the base end portion 130 when suction pressure is generated in the lumen 115 of the needle body 110.

[0045] From the viewpoint of reducing the pressure loss as described above, the inner diameter di2 of the base end portion 130 is preferably 1.1 mm or more, and more preferably 1.2 mm or more.

[0046] The distal end 120 may be configured to have a substantially constant outer diameter Do1 of 1.1 mm or less along the axial direction, and the proximal end 130 may be configured to have a substantially constant outer diameter Do2 of 1.2 mm or more along the axial direction.

[0047] The needle body 110 has a distal end 120 with an outer diameter Do1 of 1.1 mm or less, which is smaller than that of conventional tissue collection needles. This reduces the pain felt by the patient during procedures using the tissue collection needle 100. Furthermore, the needle body 110 has a proximal end 130 with an outer diameter Do2 of 1.2 mm or more, which increases the rigidity of the proximal end 130. This prevents bending of the needle body 110 during procedures using the tissue collection needle 100, thereby preventing a decrease in usability.

[0048] From the viewpoint of reducing the pain felt by the patient as described above, the outer diameter Do1 of the distal end portion 120 is preferably 1.0 mm or less, and more preferably 0.9 mm or less.

[0049] From the viewpoint of preventing the occurrence of bending during the procedure as described above, the outer diameter Do2 of the proximal end portion 130 is preferably 1.3 mm or more, and more preferably 1.4 mm or more.

[0050] The outer diameter Do3 of the tapered portion 140 can be any size depending on the difference between the outer diameter Do1 of the distal end portion 120 and the outer diameter Do2 of the proximal end portion 130. Note that the tapered portion 140 of this embodiment only needs to have an average taper angle of the inner diameter di3 of 5° or less as described above, and for example, the outer diameter Do3 does not have to be configured with the same average taper angle as the inner diameter di3.

[0051] The axial length L1 of the distal end portion 120 can be 10 mm or more. The axial length L3 of the tapered portion 140 can be 5.7 mm or more. The axial length L2 of the proximal end portion 130 can be 10 mm or more. In this embodiment, the axial length L2 of the proximal end portion 130 is defined as the linear distance from the tapered portion base end 142 to the exposed portion of the hub portion 160.

[0052] When each part of the needle main body 110 is configured with the lengths L1, L2, and L3 described above, the tissue collection needle 100 can be configured with an appropriate size that enables it to be used as an egg collection needle. Furthermore, by setting the axial length L3 of the tapered portion 140 to 5.7 mm or more, it becomes easy to configure the average taper angle of the tapered portion 140 to the desired size (5° or less), making it possible to provide a needle main body 110 that prevents the generation of the aforementioned turbulence.

[0053] The axial length L1 of the distal end portion 120 is preferably 20 mm or more, and more preferably 30 mm or more. The axial length L3 of the tapered portion 140 is preferably 7.1 mm or more, and more preferably 9.5 mm or more. The axial length L2 of the proximal end portion 130 is preferably 100 mm or more, and more preferably 130 mm or more.

[0054] When the axial lengths L1, L2, and L3 of each part of the needle main body 110 are configured as described above, the total axial length of the needle main body 110 is preferably 30 mm or more and 400 mm or less, and more preferably 200 mm or more and 350 mm or less.

[0055] The thickness t of the needle body 110 can be the same for each of the sections 120, 130, and 140 of the needle body 110. There are no particular restrictions on the size of the thickness t, but from the perspective of ensuring the rigidity of the needle body 110, it can be configured to be, for example, 0.1 mm or more. Furthermore, the thickness t is preferably 0.12 mm or more, and more preferably 0.14 mm or more.

[0056] As described above, the tissue sampling needle 100 according to this embodiment has a needle main body 110 with a lumen 115 formed therein, and the needle main body 110 has a tip end formed with a needle tip 121 that can be inserted into biological tissue, and has a tip portion 120 that extends along the axial direction with a substantially constant inner diameter di1, a base end portion 130 that is located closer to the base end than the tip portion 120 and extends along the axial direction with a substantially constant inner diameter di2, and a tapered portion 140 that is located between the tip portion 120 and the base end 130 and has an inner diameter di3 that increases from the tip end to the base end, and the inner diameter of the tip portion 120 is 0.5 mm or more, and the average taper angle of the tapered portion 140 is 5° or less.

[0057] According to the tissue collection needle 100 configured as described above, the inner diameter of the tip portion 120 is 5 mm or more, and the average taper angle of the tapered portion 140 is 5° or less, so that when the collected biological tissue moves within the tip portion 120 and when it moves through the tapered portion 140, stress can be prevented from being placed on the cells of the biological tissue.

[0058] <Examples> Next, examples will be described. Note that the configuration of the present invention is not limited to the contents of the examples described below.

[0059] The following sample 1 was prepared as the needle main body 110 according to the embodiment (see FIG. 6(A)). <Sample 1> Inner diameter di1 of tip portion 120 = 0.71 mm Inner diameter di2 of base end portion 130 = 1.22 mm Average taper angle = 0.17° Axial length L1 of tip portion 120 = 24 mm Axial length L3 of tapered portion 140 = 170 mm.

[0060] The following sample 2 was prepared as a needle body 310 according to a comparative example (see FIG. 6(B)). <Sample 2> Inner diameter di1 of tip portion 320 = 0.67 mm Inner diameter di2 of base end portion 330 = 1.20 mm Average taper angle = 14.84° Axial length L1 of tip portion 120 = 50 mm Axial length L3 of tapered portion 140 = 2 mm.

[0061] FIG. 7 shows the results of a simulation of the pressure inside the needle performed for Sample 1 and Sample 2 under the condition of a volumetric flow rate of 50 mL / min.

[0062] 7, the vertical axis represents pressure, and the horizontal axis represents the position from the tip of each needle main body 110, 310. The slope of the graph represents local pressure loss, and the absolute value of the pressure at a position 370 mm from the tip represents the pressure loss throughout the needle.

[0063] 7, the inner diameter of the tip 120 of Sample 2 is smaller than that of Sample 1, resulting in a large local pressure loss. In addition, near the tapered portion 340 (approximately 50 mm from the tip), an extreme value of pressure is observed due to turbulence caused by the sudden increase in the inner diameter of the needle main body 310.

[0064] In Sample 1, the inner diameter di1 of the tip portion 120 is 0.71 mm, which is larger than that of the tip portion 320 of Sample 2. As a result, local pressure loss at the tip portion is small. Furthermore, in Sample 1, the average taper angle of the tapered portion 140 is 0.17°, which is sufficiently smaller than that of Sample 2. As a result, no extreme values ​​of pressure caused by turbulence in the flow are observed.

[0065] To reduce pressure loss, it is necessary to lengthen the section of the needle with a larger inner diameter. Compared to Sample 2, Sample 1 has a gradually increasing inner diameter, which is disadvantageous in terms of pressure loss. However, when comparing Sample 1 and Sample 2, the pressure loss across the needle is the same. This is thought to be due to the fact that the inner diameter of the tip 120 of Sample 1 is larger than that of Sample 2.

[0066] FIG. 8 shows the results of a shear stress simulation performed on Sample 1 and Sample 2.

[0067] In the graph of FIG. 8, the vertical axis indicates the magnitude of shear stress on the central axis calculated from the velocity distribution of the flow field formed in the lumen, and the horizontal axis indicates the position from the tip of each needle main body 110, 310.

[0068] 8, it can be seen that the inner diameter of the needle body 310 increases rapidly near the tapered portion 340 of Sample 2 (at a position approximately 50 mm from the tip), resulting in increased shear stress in the flow field. On the other hand, the inner diameter of the needle body 310 also increases near the tapered portion 140 of Sample 1 (at a position approximately 24 mm from the tip), resulting in a tendency for the shear stress in the flow field to increase somewhat. However, because the average taper angle of the tapered portion 140 of Sample 1 is sufficiently smaller than that of Sample 2, it can be seen that the shear stress is significantly reduced compared to Sample 2.

[0069] From the results of the examples and comparative examples, it was confirmed that the needle main body 110 of sample 1 has a larger inner diameter of the tip 120 than the needle main body 310 of sample 2, and has a smaller average taper angle, which makes it possible to reduce pressure loss to a similar level to that of sample 2, and to significantly reduce the shear stress applied to biological tissue by the tapered portion 140 compared to sample 2.

[0070] Next, a modified example of the embodiment described above will be described. In the description of the modified example, detailed description of the contents already described in the embodiment described above will be omitted.

[0071] FIG. 9 shows a part of a needle main body 110A according to the first modification.

[0072] As shown in Fig. 9, the tapered portion 140 may be configured to have a plurality of tapered portions. For example, as shown in Fig. 9, the tapered portion 140 may be configured to have two tapered portions 140A and 140B.

[0073] The tapered portion 140 of variant example 1 has a first tapered portion 140A extending from the base end of the tip portion 120 toward the base end side, and a second tapered portion 140B extending from the base end of the first tapered portion 140A toward the base end side.

[0074] The average taper angle of the first tapered portion 140A can be configured to be larger than the average taper angle of the second tapered portion 140B. In this modification, the average taper angles of the tapered portions 140A and 140B are both 5° or less. The average taper angle of the first tapered portion 140A can be, for example, 5° or less, and the average taper angle of the second tapered portion 140B can be, for example, 4° or less.

[0075] As shown in this modification, there is no particular limit to the number of tapered portions provided on needle body 110A, as long as the average taper angle is 5° or less. For example, it is possible to provide three or more tapered portions on needle body 110A.

[0076] FIG. 9 shows a part of a needle main body 110C according to a second modification.

[0077] As shown in Fig. 9, the tapered portion 140C may extend in a curved line from the distal end to the proximal end. The tapered portion 140C according to Modification 2 has a shape that widens from the distal end to the proximal end, moving away from the central axis c1. Even with this configuration, the same effects as those of the above-described embodiment can be achieved as long as the average taper angle of the tapered portion 140C is 5° or less. As described above in this modification, the shape of the tapered portion 140C (the cross-sectional shape of the lumen 115 along the axial direction) is not limited to a linear shape.

[0078] Although the tissue collection needle according to the present invention has been described through embodiments and modified examples, the present invention is not limited to the configurations described in the specification, and can be modified as appropriate based on the claims.

[0079] This application is based on Japanese Patent Application No. 2024-042524, filed on March 18, 2024, the disclosure of which is incorporated herein by reference in its entirety.

[0080] 10 Tissue sampling device 100 Tissue sampling needle 110 Needle body 110A Needle body 110C Needle body 115 Lumen 120 Tip 121 Needle tip 121a Tip opening 130 Base end 140 Tapered portion 140A First tapered portion 140B Second tapered portion 140C Tapered portion 141 Tapered portion tip 142 Tapered portion base end 160 Hub portion 200 Suction portion di1 Inner diameter of tip di2 Inner diameter of base di3 Inner diameter of tapered portion Do1 Outer diameter of tip Do2 Outer diameter of base Do3 Outer diameter of tapered portion c1 Central axis t Wall thickness

Claims

1. A tissue sampling needle having a needle body with a lumen formed therein, the needle body having: a distal end having a needle tip at its tip that can be inserted into biological tissue and extending with a substantially constant inner diameter along the axial direction; a proximal end that is located proximal to the distal end and extends with a substantially constant inner diameter along the axial direction; and a tapered portion that is located between the distal and proximal ends and whose inner diameter increases from the distal end to the proximal end, the inner diameter of the distal end being 0.5 mm or more, and the average taper angle of the tapered portion being 5° or less.

2. The tissue collection needle according to claim 1, wherein the inner diameter of the proximal end is 1.0 mm or greater.

3. A tissue sampling needle as claimed in claim 1, wherein said tip portion extends along said axial direction at a substantially constant outer diameter of 1.1 mm or less, and said base portion extends along said axial direction at a substantially constant outer diameter of 1.2 mm or more.

4. The tissue sampling needle according to claim 1, wherein the axial length of the tip portion is 10 mm or more, the axial length of the tapered portion is 5.7 mm or more, and the axial length of the base end portion is 10 mm or more.

5. A tissue sampling needle as described in claim 1, wherein the tapered portion has a first tapered portion extending from the base end of the tip portion toward the base end side, and a second tapered portion extending from the base end of the first tapered portion toward the base end side, and the average taper angle of the first tapered portion is greater than the average taper angle of the second tapered portion.

6. The tissue sampling needle according to claim 1, wherein the tapered portion extends linearly or curvedly from the distal end to the proximal end.

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