WO2025203782A1 - Hollow needle for medical use - Google Patents

Abstract

A hollow needle (1) for medical use has a cylindrical shape in which a needle tip (10) is formed on a tip side (TS). When the direction along an axis (9) of the cylinder, extending from the tip side (TS) to a base side (BS), is treated as an axial direction (SD), and the direction along the circumference of the cylinder is treated as a circumferential direction (PD), three or more pointed sections (11) that taper toward the tip side (TS) are formed in the needle tip (10) with intervals therebetween in the circumferential direction (PD), and cutting blades (12) that are recessed toward the base side (BS) are formed between each of the three or more pointed sections (11). Recess bottom sections (13) that are located furthest to the base side (BS) in each the three or more cutting blades (12) are formed in different locations in the axial direction (SD).

Description

Medical hollow needles

This disclosure relates to medical hollow needles.

JP 2020-518369 A discloses a biopsy needle having, at the distal end of an elongated body extending along a longitudinal axis, at least four tines with post-grinding bevels formed on two grinding surfaces, and a notch with a V-shaped portion located between two adjacent tines.

The biopsy needle described in JP 2020-518369 A was developed primarily to obtain tissue samples with a high success rate. However, modern medical needles are required to offer reduced resistance when puncturing.

In consideration of the above-mentioned issues, the present disclosure relates to providing a medical hollow needle that reduces resistance during puncture.

The medical hollow needle according to the first aspect of the present disclosure is a medical hollow needle having a cylindrical shape with the needle tip formed at the distal end. When the axial direction is the direction along the axis of the cylindrical shape extending from the distal end to the proximal end opposite the distal end, and the circumferential direction is the direction along the circumference of the cylindrical shape, the needle tip has three or more sharp points formed at the distal end at intervals in the circumferential direction, and a cutting blade recessed toward the proximal end is formed between each of the three or more points, and the recessed bottoms located closest to the proximal end of each of the three or more cutting blades are formed at different positions in the axial direction.

Furthermore, as a medical hollow needle according to a second aspect of the present disclosure, in the medical hollow needle according to the first aspect of the present disclosure, the cutting edge may have a U-shaped curved shape.

Furthermore, as a medical hollow needle according to the third aspect of the present disclosure, in the medical hollow needle according to the first aspect of the present disclosure, the distance between adjacent concave bottom portions in the axial direction may be equal to or greater than the thickness of the object to be punctured.

Furthermore, as a medical hollow needle according to a fourth aspect of the present disclosure, in the medical hollow needle according to the first aspect of the present disclosure, when the hollow needle is viewed in the axial direction from the tip side, if imaginary lines are drawn extending radially from the center of gravity of the circumference of the cylindrical shape to each of three or more concave bottom portions, the angle Θx formed by adjacent imaginary lines is given by, when the number of concave bottom portions is A, the inner diameter of the cylindrical shape of the hollow needle is B, the axial distance between axially adjacent concave bottom portions is C, and the inclination angle with respect to the axis of the surface of the cutting edge that cuts from the inner surface to the outer surface of the hollow needle at the concave bottom portion is θ:
The range may be Arccos{1-(C×tan θ/(B/2))}≦Θx.

Furthermore, as a medical hollow needle according to a fifth aspect of the present disclosure, in the medical hollow needle according to the first aspect of the present disclosure, the three or more concave bottoms include a first concave bottom, a second concave bottom, a third concave bottom, and a fourth concave bottom, which appear in that order when viewed in the axial direction from the tip side to the base end, and when the hollow needle is viewed in the axial direction from the tip side, the first concave bottom and the second concave bottom may be arranged in opposing positions across the center of gravity of the circumference of the cylindrical shape, and the third concave bottom and the fourth concave bottom may be arranged in opposing positions across the center of gravity, or the first concave bottom and the fourth concave bottom may be arranged in opposing positions across the center of gravity, and the second concave bottom and the third concave bottom may be arranged in opposing positions across the center of gravity.

Furthermore, as a medical hollow needle according to a sixth aspect of the present disclosure, in the medical hollow needle according to the first aspect of the present disclosure, the inclination angle θ relative to the axis of the cutting edge surface cut from the inner surface of the hollow needle toward the outer surface at the concave bottom portions is, when the number of concave bottom portions is A, the inner diameter of the cylindrical shape of the hollow needle is B, and the axial distance between adjacent concave bottom portions in the axial direction is C,
The relationship θ≦Arctan{((B/(A−1))/C} may be satisfied.

With the medical hollow needle disclosed herein, the puncture resistance when the needle tip pierces the target is distributed according to the number of concave bottoms, thereby reducing resistance during puncture.

FIG. 1 is a partial side view of a medical hollow needle according to one embodiment. 1 is a partially exploded view of a medical hollow needle according to one embodiment, cut sideways along the axial direction and unfolded. FIG. 1 is an end view of a medical hollow needle according to one embodiment, viewed from the tip side. FIG. 1 is a schematic configuration diagram of a processing device for producing a medical hollow needle according to one embodiment. FIG. 1A to 1C are diagrams illustrating a process for producing a medical hollow needle according to one embodiment. 1A to 1C are diagrams illustrating a process for producing a medical hollow needle according to one embodiment. 1A to 1C are diagrams illustrating a process for producing a medical hollow needle according to one embodiment. 1A to 1C are diagrams illustrating a process for producing a medical hollow needle according to one embodiment. FIG. 10 is a side cross-sectional view illustrating the angle between the axis and the cutting edge surface of a medical hollow needle according to one embodiment. FIG. 10 is a conceptual diagram illustrating the circumferential distance between circumferentially adjacent concave bottom portions in a medical hollow needle according to one embodiment. FIG. 10 is a conceptual diagram illustrating the circumferential distance between circumferentially adjacent concave bottom portions in a medical hollow needle according to one embodiment. FIG. 10 is a conceptual diagram illustrating the circumferential distance between circumferentially adjacent concave bottom portions in a medical hollow needle according to one embodiment. 1 is a conceptual diagram illustrating the action of a medical hollow needle according to one embodiment. FIG. FIG. 10 is a conceptual diagram illustrating the action of a medical hollow needle according to a comparative example.

The following describes the embodiments with reference to the drawings. Note that identical or similar reference numerals are used to designate identical or corresponding components in each drawing, and redundant explanations will be omitted.

First, referring to Figure 1, a medical hollow needle 1 (hereinafter simply referred to as "hollow needle 1") according to one embodiment will be described. Figure 1 is a partial side view of hollow needle 1. Hollow needle 1 is typically used as a needle for puncturing tissue, such as an injection needle or biopsy needle, and Figure 1 partially shows the end side that penetrates the target 99 to be punctured, such as tissue. In the following description, the end side of hollow needle 1 that penetrates the target 99 to be punctured will be referred to as the "tip side TS," and the end side opposite tip side TS that is connected to a syringe (not shown) or the like will be referred to as the "base side BS."

The hollow needle 1 has a tubular shape, and in this embodiment is formed in a cylindrical shape. The axis 9 of the tubular shape that constitutes the hollow needle 1 extends from the distal end TS to the proximal end BS (or from the proximal end BS to the distal end TS). In the following description, the direction in which the axis 9 of the tubular shape that constitutes the hollow needle 1 extends will be referred to as the "axial direction SD", and the direction along the circumference in a cross section perpendicular to the axis 9 of the tubular shape will be referred to as the "circumferential direction PD". The inner side surface of the tubular shape that constitutes the hollow needle 1 will be referred to as the "inner surface 3", and the outer side surface will be referred to as the "outer surface 5". The surface where the periphery (circumference in this embodiment) of the tubular shape that constitutes the hollow needle 1 appears will be referred to as the "end surface".

The hollow needle 1 has a needle tip 10 formed on the distal end side TS. The needle tip 10 corresponds to the end surface of the distal end side TS of the cylindrical shape that constitutes the hollow needle 1, and is the part that comes into contact with the puncture target 99 before the outer surface 5 when the hollow needle 1 punctures the puncture target 99. The needle tip 10 has a sharp tip 11 formed on the distal end side TS. Here, "sharp" means sharp enough to be able to puncture the puncture target 99. The tip 10 has a sharp tip 11 that appears on the periphery of the end surface of the distal end side TS of the cylindrical shape. Three or more tips 11 are formed at intervals in the circumferential direction PD; in this embodiment shown in Figure 1, four tips are formed. The number of tips 11 formed on the needle tip 10 can be determined appropriately depending on the diameter of the hollow needle 1; the larger the diameter of the hollow needle 1, the more tips can be formed. However, considering the diameter of the hollow needle 1 used as an injection needle or biopsy needle, the number of tips 11 is preferably eight or less, and more preferably six or less, from the standpoint of durability and processing precision of the hollow needle 1. The tips 11 do not need to be aligned in the axial direction SD.

The needle tip 10 also has cutting edges 12 formed between adjacent cusps 11. The cutting edges 12 are recessed toward the base end BS. When viewed along the axial direction SD, the boundary between the cutting edges 12 and the outer surface 5 is closer to the base end BS than the boundary with the inner surface 3. With this configuration, the cutting edges 12 appear not only on the end face of the hollow needle 1, but also on the side faces. The cutting edges 12 have sharp boundaries with the inner surface 3, and can cut through the puncture target 99 via these boundaries with the inner surface 3. Typically, the same number of cutting edges 12 as the number of cusps 11 are formed; in this embodiment, four cutting edges are formed. In this embodiment, each cutting edge 12 has a U-shaped curved shape recessed toward the base end BS. The portion of each cutting edge 12 that is located closest to the base end BS of the U-shaped curved shape is referred to as the "concave bottom 13."

The concave bottom 13 is typically the portion of the U-shaped curved cutting edge 12 where, when the puncture surface 99F of the puncture target 99 is considered to be a plane, the tangent line TL to the curve is parallel to the puncture surface 99F when the needle tip 10 punctures the puncture surface 99F in the direction normal to the puncture surface 99F. The U-shaped curved shape, which is the locus of the boundary between the cutting edge 12 and the inner surface 3, is typically smoothly connected overall, and the curve recessed toward the base end BS can be viewed as a curve that can be differentiated at any point. This configuration allows the hollow needle 1 to prevent stress from concentrating on the concave bottom 13 in its structure. In the U-shaped curved cutting edge 12, the puncture resistance is greatest where the tangent line TL is parallel to the puncture surface 99F of the puncture target 99, i.e., the concave bottom 13.

There are the same number of recessed bottoms 13 as the number of cutting edges 12, and in this embodiment there are four. Hereinafter, to distinguish between the four recessed bottoms 13 in this embodiment, they may be referred to as the first recessed bottom 13A, the second recessed bottom 13B, the third recessed bottom 13C, and the fourth recessed bottom 13D in order of proximity to the tip side TS. However, when referring to common matters without distinguishing between the four recessed bottoms 13A, 13B, 13C, and 13D, they will be collectively referred to as "recessed bottoms 13." In the axial direction SD, the first recessed bottom 13A and the second recessed bottom 13B are adjacent to each other, the second recessed bottom 13B and the third recessed bottom 13C are adjacent to each other, and the third recessed bottom 13C and the fourth recessed bottom 13D are adjacent to each other. "The recessed bottoms 13 are adjacent in the axial direction SD" means, in other words, that when the hollow needle 1 is projected in a direction perpendicular to the axial direction SD, the recessed bottoms 13 that appear on the projection surface are adjacent in the axial direction SD.

The concave bottom portion 13 will be explained in more detail with reference to Figure 2. Figure 2 is a partial exploded view of the hollow needle 1 cut sideways along the axial direction SD and unfolded. The example shown in Figure 2 is cut in the axial direction SD from the tip 11 located at the most distal end TS and unfolded. The exploded view shown in Figure 2 makes it easy to understand the positional relationship of the concave bottom portion 13 in the axial direction SD when the hollow needle 1 is projected in a direction perpendicular to the axial direction SD. As can be clearly seen from Figure 2, the needle tip 10 of the hollow needle 1 has three or more concave bottom portions 13 (four concave bottom portions 13A, 13B, 13C, and 13D in this embodiment), each of which is located at a different position in the axial direction SD. In other words, none of the concave bottom portions 13A, 13B, 13C, and 13D is located at the same distance from the most distal end of the needle tip 10 in the axial direction SD (the cut tip 11 in the example shown in Figure 2). In this way, by arranging three or more recessed bottoms 13 offset in the axial direction SD, the areas with the greatest puncture resistance are dispersed, making it possible to suppress the maximum puncture resistance and reduce the puncture burden.

Regarding each of the recessed bottoms 13A, 13B, 13C, and 13D, adjacent recessed bottoms 13 exist at an interval in the axial direction SD. Hereinafter, the interval C1 between the first recessed bottom 13A and the second recessed bottom 13B, the interval C2 between the second recessed bottom 13B and the third recessed bottom 13C, and the interval C3 between the third recessed bottom 13C and the fourth recessed bottom 13D in the axial direction SD will be collectively referred to as the axial interval C. Generalizing the axial interval C, it can be seen as representing the interval between the nth (n is a natural number) recessed bottom 13 from the tip side TS and the (n+1)th recessed bottom 13 in the axial direction SD. It is preferable that the axial interval C be equal to or greater than a predetermined distance. This predetermined distance typically corresponds to the thickness of the puncture target 99 (see Figure 1). Examples of the puncture target 99 include the wall of a blood vessel (e.g., a vein) and a layered portion of biological tissue. If the axial spacing C is equal to or greater than the thickness of the puncture target 99, each of the four cutting blades 12 can completely penetrate the thickness of the puncture target 99, thereby appropriately distributing the puncture resistance. Considering that the puncture target 99 is biological tissue, the thickness of the blood vessel wall and the thickness of each layer of layered tissue are often 500 μm or less, so the above-mentioned predetermined distance defining the axial spacing C may be 500 μm. On the other hand, considering that the thickness of the wall of an organ such as the stomach is less than 3 mm, the axial spacing C may be 3 mm or less. Furthermore, taking into account the thickness of the puncture target 99, the axial spacing C may be 0.8 mm to 2 mm, or 1 mm to 1.5 mm. The axial spacings C1, C2, and C3 may all be the same value, or some or all of them may be different values.

With reference also to Figure 3, the arrangement of each concave bottom portion 13A, 13B, 13C, and 13D in the circumferential direction PD will be explained. Figure 3 is an end view of the hollow needle 1 as viewed from the tip side TS. The end view of Figure 3 can also be said to be a view of the hollow needle 1 as viewed from the tip side TS, facing a virtual plane perpendicular to the axial direction SD. Since the hollow needle 1 is cylindrical in this embodiment, the end view of Figure 3 shows a circumference that is the shape of the cylindrical end face, and the center G of this circumference corresponds to the center of gravity of the circumference. When tracing the end view of Figure 3 clockwise in the circumferential direction PD, the concave bottom portions 13 appear in the order of first concave bottom portion 13A, third concave bottom portion 13C, fourth concave bottom portion 13D, and second concave bottom portion 13B. In this way, when four or more recessed bottoms 13 are formed, it is preferable that the order in which they appear when traced in the axial direction SD from the tip side TS as shown in Figures 1 and 2 is different from the order in which they appear when traced in the circumferential direction PD as viewed from the tip side TS as shown in Figure 3.

In the example shown in Figure 3, when viewed from the tip side TS in the axial direction SD, the first concave bottom 13A and the fourth concave bottom 13D are arranged in positions facing each other across the center G, and the second concave bottom 13B and the third concave bottom 13C are arranged in positions facing each other across the center G. Here, two concave bottoms 13 arranged in positions facing each other across the center G means that they are not adjacent to each other in the circumferential direction PD. Note that, as in the example shown in Figure 3, for concave bottoms 13 arranged in positions facing each other across the center G, such as the first concave bottom 13A and the fourth concave bottom 13D, the imaginary line VL1 connecting the center G and the first concave bottom 13A and the imaginary line VL4 connecting the center G and the fourth concave bottom 13D may be substantially in the same line. Here, "substantially in a straight line" is intended to include not only cases where the two imaginary lines VL1 and VL4 are in a straight line, but also cases where one imaginary line VL1 is extended to the opposite circumference and the angle it forms with the other imaginary line VL4 is within a range of approximately 10°. In this way, if the order in which the concave bottoms 13 appear when traced in the axial direction SD is different from the order in which they appear when traced in the circumferential direction PD, or if they are positioned opposite each other across the center G in the above-mentioned relationship, it is possible to prevent the hollow needle 1 from losing balance in the circumferential direction PD when puncturing the target 99.

The hollow needle 1 configured as described above typically has a cutting edge 12 with a concave bottom 13 formed using an ultrashort pulse laser. Because the pulse width of an ultrashort pulse laser is short and it is less likely to cause damage to the workpiece due to heat, such as melting, it is possible to perform high-quality micromachining, such as forming multiple U-shaped cutting edges 12 on the needle tip 10.

Figure 4 shows a schematic diagram of the processing device 30 that processes a pipe 91 into a hollow needle 1 (see Figure 1). The processing device 30 is equipped with a laser oscillator 34, a stage 35, an air blower 38, and a dust collector 39. The processing device 30 is a device that processes a metal pipe 91, which is the raw material for the hollow needle 1, into a hollow needle 1 by holding the metal pipe 91 on the stage 35 and irradiating the pipe 91 with a laser 49 from the laser oscillator 34.

The laser oscillator 34 has an oscillator 41, a pulse modulator 42, a power controller 43, a wavelength changer 44, a galvanic scanner 45, and an fθ lens 46. The oscillator 41 generates laser light. The pulse modulator 42 modulates the pulses of the laser light generated by the oscillator 41. The power controller 43 changes the power of the laser light pulse-modulated by the pulse modulator 42. The wavelength changer 44 changes the wavelength of the laser light whose power has been changed by the power controller 43. By shortening the wavelength of the laser light with the wavelength changer 44, the pipe 91 can be processed more neatly. The irradiation direction of the laser light whose wavelength has been changed by the wavelength changer 44 is controlled by the galvanic scanner 45, and it is irradiated as a laser 49 via the fθ lens 46. The laser 49 irradiated from the laser oscillator 34 is an ultrashort pulse laser.

The stage 35 has a rotating stage 51, a tilting stage 52, and an XYZ stage 53. The rotating stage 51 holds the pipe 91 so that it can rotate around its axis. In this embodiment, the axis of the pipe 91 held by the rotating stage 51 extends horizontally in the standard position. The standard position refers to a state in which no tilting is performed by operating the tilting stage 52. In the standard position, the horizontal direction perpendicular to the direction in which the axis of the pipe 91 held by the rotating stage 51 extends is referred to as the "X direction," the direction in which the axis of the pipe 91 held by the rotating stage 51 extends is referred to as the "Y direction," and the vertical direction perpendicular to the X and Y directions is referred to as the "Z direction." The tilting stage 52 tilts the tip of the pipe 91 held by the rotating stage 51 (i.e., the end opposite the side held by the rotating stage 51) typically by moving it up and down (i.e., in the Z direction). The XYZ stage 53 moves the pipe 91 held by the rotation stage 51 in the X, Y, and Z directions. In this embodiment, the stage 35 has a tilt stage 52 provided on the XYZ stage 53, and a rotation stage 51 provided on the tilt stage 52.

In the processing device 30, a laser 49 emitted from a laser oscillator 34 is directed at a pipe 91 held on a stage 35, while the pipe 91 is moved and/or rotated in an appropriate direction on the stage 35, thereby cutting predetermined locations of the pipe 91 with the laser 49 and processing the pipe 91. When cutting the pipe 91 with the laser 49, air is supplied from an air blower 38 toward the cutting location, and cutting chips blown away by the air supplied from the air blower 38 are sucked into and collected by a dust collector 39. After a predetermined location has been cut, the pipe 91 held on the stage 35 is moved in the X direction, Y direction, or Z direction, tilted, and/or rotated as appropriate to cut the next predetermined location. When all predetermined locations have been cut in the processing device 30, a hollow needle 1 (see Figure 1) is produced. In addition, the start/stop and operation of the laser oscillator 34, stage 35, air blower 38, and dust collector 39 in the processing device 30 are typically controlled by a control device (not shown).

Figures 5A to 5D show examples of how the pipe 91 is processed to produce the hollow needle 1. In the following description, when referring to the configuration of the hollow needle 1, reference will be made to Figures 1 to 3 as appropriate. When producing a hollow needle 1 having four concave bottoms 13, as in this embodiment, first, as shown in Figure 5A, the pipe 91 is cut at the appropriate locations to form two concave bottoms 13 (e.g., a first concave bottom 13A and a fourth concave bottom 13D) that face each other across the center G when viewed from the tip side TS. Here, when forming two concave bottoms 13, the first concave bottom 13 is formed first, and then the stage 35 is controlled to appropriately change the orientation of the pipe 91 to form the second concave bottom 13. Once the two recessed bottom portions 13 have been formed, the stage 35 is controlled to appropriately change the orientation of the pipe 91, and that portion of the pipe 91 is cut so as to form a recessed bottom portion 13 (e.g., third recessed bottom portion 13C) adjacent to the two previously formed recessed bottom portions 13 in the circumferential direction PD, as shown in FIG. 5B. Thereafter, the stage 35 is controlled to appropriately change the orientation of the pipe 91, and that portion of the pipe 91 is cut so as to form the remaining recessed bottom portion 13 (e.g., second recessed bottom portion 13B), as shown in FIG. 5C. In this way, a hollow needle 1 such as that shown in FIG. 5D is produced.

When the hollow needle 1 is produced by cutting the pipe 91 as described above, the angle at which the pipe 91 is cut should be set as follows to ensure that the axial distance C is equal to or greater than a predetermined distance.

6 is a side cross-sectional view of a pipe 91 illustrating the angle (hereinafter referred to as the "inclination angle θ") between the cut surface CF of the pipe 91 and the axis 9 of the pipe 91, which is formed by moving the pipe 91 in the Y direction while applying the laser 49 in the processing device 30 shown in FIG. 4. More specifically, the inclination angle θ is the angle between the cut surface CF of the pipe 91 and an imaginary plane extending above and below the axis 9 of the pipe 91 in the Z direction when the laser 49 is applied in the Z direction, and is sometimes referred to as the bevel angle. In a hollow needle 1 produced by processing a pipe 91, when the number of formed recessed bottoms 13 is A, the inner diameter of the pipe 91 (and therefore the hollow needle 1) is B, and the axial distance in the axial direction SD between adjacent recessed bottoms 13 is C [μm] (corresponding to the axial distance C), the inclination angle θ may be determined within a range that satisfies the following formula:
θ≦Arctan {((B/(A-1))/C} ...(1)

The above formula (1) will now be explained. In reality, the cut surfaces CF of each cutting edge 12 appear in various directions as shown in Figures 5A to 5D, but for ease of explanation, they will be aligned in the same direction (represented as "virtual cut surfaces VCF" in Figure 6). For example, in Figure 6, the cut surface CF1 on the tip side TS that slopes downward to the right becomes the virtual cut surface VCF1 when aligned to slope upward to the right. If the axial spacing C between adjacent cut surfaces CF or virtual cut surfaces VCF is expressed as the spacing in the direction of the inner diameter B (hereinafter referred to as "radial spacing P"), then the radial spacing P is "P = C x tan θ". On the other hand, in FIG. 6 , the maximum distance in the direction of inner diameter B between the imaginary cut surface VCF1 on which the recessed bottom portion 13 closest to the distal end TS of the cut surfaces CF or imaginary cut surfaces VCF is formed and the imaginary cut surface VCF on which the recessed bottom portion 13 closest to the proximal end BS is formed (hereinafter referred to as the "imaginary cut surface BVCF") cannot be greater than the inner diameter B, and is therefore equal to the size of the inner diameter B. The distance between cut surface CF1 and imaginary cut surface BVCF in the direction of inner diameter B is a radial distance P equal to (A-1), which is the number A of recessed bottom portions 13 formed minus 1. Therefore, it is preferable to set one radial distance P to a value equal to or less than the value obtained by dividing the inner diameter B by (A-1), i.e., "P≦(B/(A-1))." Substituting the above-mentioned "P=C×tan θ" into this equation and rearranging, we obtain the above equation (1).

Next, a preferred spacing between adjacent recessed bottom portions 13 in the circumferential direction PD when viewed from the tip side TS in the axial direction SD will be described. As shown in FIG. 3 , the spacing between the recessed bottom portions 13 in the circumferential direction PD can be expressed as the angle (hereinafter referred to as the "spacing angle Θx") formed by adjacent imaginary lines VL when imaginary lines VL are drawn from the center G to each of three or more (four in this embodiment) recessed bottom portions 13. Regarding the imaginary line VL, the line drawn from the center G to the first recessed bottom portion 13A will be referred to as the "imaginary line VL1." Following this, the line drawn to the second recessed bottom portion 13B will be referred to as the "imaginary line VL2," the line drawn to the third recessed bottom portion 13C will be referred to as the "imaginary line VL3," and the line drawn to the fourth recessed bottom portion 13D will be referred to as the "imaginary line VL" when no distinction is made. By appropriately ensuring the spacing angle Θx, the hollow needle 1 can distinguish adjacent recessed bottoms 13 in the circumferential direction PD as separate entities, in other words, it is possible to prevent two adjacent recessed bottoms 13 in the circumferential direction PD from becoming one with each other, and it is possible to appropriately distribute the resistance during puncture. From this perspective, the spacing angle Θx should be determined within a range that satisfies the following formula, where A is the number of recessed bottoms 13 in the hollow needle 1, B is the inner diameter of the pipe 91 (and therefore the hollow needle 1), C [μm] is the spacing in the axial direction SD between adjacent recessed bottoms 13, and θ is the inclination angle:
Arccos {1-(C×tanθ/(B/2))}≦Θx...(2)

The above formula (2) will be explained with reference to Figures 7A to 7C. As shown in Figure 7A, in an XYZ coordinate system, when a pipe 91 is cut at a first cut surface CF1 inclined by an inclination angle θ (see Figure 7B) in the Z-axis direction with respect to the XY plane, with the X axis as the rotation axis, the position of point E1 (X1, Y1, Z1) where an imaginary plane inclined by an angle Θa in the Z-axis direction with respect to the XY plane, with the Y axis as the rotation axis, intersects with cut surface CF1 is as follows. Note that referring to Figure 7B will help understanding of Y1. Figure 7B shows the inclination angle θ and point E1 on a plane that passes through X1 and is parallel to the YZ plane.
X1=(B/2)×cosΘa
Y1=((B/2)×sinΘa)/tanθ
Z1 = (B/2) × sin Θa

Next, as shown in Figure 7C, if the position of the concave bottom 13 is shifted by an amount C toward the base end in the axial direction SD from the first cut surface CF1 and the pipe 91 is cut by a second cut surface CF2 having an inclination angle θ, the Y-coordinate position Y2 at point E2 where the cut surface CF2 intersects with an imaginary plane inclined by an angle (Θa + Θx) in the Z-axis direction with respect to the XY plane, with the Y axis as the axis of rotation, will be as follows, following point E1:
Y2=((B/2)×sin(Θa+Θx))/(tanθ+C)

The intersection of the first cut surface CF1 and the second cut surface CF2 has the same Y coordinate position, so Y1=Y2, which leads to the following relationship:
((B/2)×sinΘa)/tanθ=((B/2)×sin(Θa+Θx))/(tanθ+C)...(3)
To derive the boundary conditions, when the adjacent concave bottoms 13 are closest and the concave bottom 13 of the first cut surface CF1 intersects with the second cut surface CF2, Θa is 90°, so by substituting Θa = 90° into the above equation (3), the following value is obtained.
Θx=Arccos {1-(C×tanθ/(B/2))} ...(4)
The interval angle Θx only needs to be larger than the value of the above formula (4), and therefore is given by the above formula (2).

Next, the function of the hollow needle 1 will be explained with reference to Figure 8A. In Figure 8A, the hollow needle 1 itself is the same as that shown in Figure 1, but differs from Figure 1 in that a graph is also included. The graph included in Figure 8A has the puncture resistance on the vertical axis and the puncture position on the horizontal axis. The puncture position on the horizontal axis is typically the position of the hollow needle 1 in the axial direction SD relative to the puncture surface 99F of the puncture target 99. To puncture the hollow needle 1 into the puncture target 99, the needle tip 10 is placed opposite the puncture target 99 and the hollow needle 1 is moved in the axial direction SD toward the puncture target 99, puncturing the needle tip 10 into the puncture target 99. At this time, the tip 11 located at the most distal end TS comes into contact with the puncture target 99 first, and the cutting edges 12 on both sides extending from the tip 11 enter the puncture target 99. When the hollow needle 1 is further moved in the axial direction SD toward the puncture target 99, in this embodiment, the tip 11 second from the tip side TS in the axial direction SD comes into contact with the puncture target 99, and the cutting edges 12 on both sides of that tip 11 enter the puncture target 99. In this embodiment, the first and second tips 11 from the tip side TS in the axial direction SD are positioned opposite each other across the center G (see Figure 3) of the circumference of the cylindrical hollow needle 1 as seen from the tip side TS, allowing the hollow needle 1 to stably puncture the puncture target 99. If the tips 11 were offset to one side on the circumference as seen from the tip side TS, the balance of resistance could be disrupted, causing the hollow needle 1 to bend and puncture the puncture target 99; however, the positioning of the tips 11 in this embodiment prevents the hollow needle 1 from bending.

When the hollow needle 1 is then moved further in the axial direction SD toward the puncture target 99, in this embodiment, the tip 11 located third from the tip side TS in the axial direction SD comes into contact with the puncture target 99. When the hollow needle 1 is moved further in the axial direction SD toward the puncture target 99 from here, the first concave bottom 13A between the first tip 11 and the third tip 11 enters the puncture target 99. At this time, as can be seen from the graph also shown in Figure 8A, the puncture resistance increases as the angle of the curve forming the boundary between the inner surface 3 of the cutting edge 12 from the tip 11 to the first concave bottom 13A with respect to the axial direction SD increases. The puncture resistance is then maximized at the first concave bottom 13A, where the angle with respect to the axial direction SD is greatest (a right angle in this embodiment). Thereafter, when the puncture position passes the first concave bottom 13A, the puncture resistance temporarily decreases, then increases toward the second concave bottom 13B, and reaches a maximum at the second concave bottom 13B. Thereafter, the puncture resistance repeatedly decreases and increases toward the third concave bottom 13C and the fourth concave bottom 13D. The puncture resistance typically exhibits increasing maximum values in the order of the first concave bottom 13A, the second concave bottom 13B, the third concave bottom 13C, and the fourth concave bottom 13D, reaching a maximum at the fourth concave bottom 13D. In this embodiment, when the puncture position passes the fourth concave bottom 13D, the puncture resistance becomes smaller than the minimum value between the first concave bottom 13A and the second concave bottom 13B, and thereafter shows almost no change. In this way, in the hollow needle 1 according to this embodiment, all of the recessed bottoms 13 are formed at different positions in the axial direction SD, so the puncture resistance is distributed according to the number of recessed bottoms 13, making it possible to suppress the maximum value of the puncture resistance.

8B shows the configuration of a commonly used hollow needle 101 according to a comparative example, along with a graph of the relationship between the puncture position and the puncture resistance. The hollow needle 101 according to the comparative example has two concave bottoms 13 and two points 11. In the hollow needle 101 according to the comparative example, the two concave bottoms 13 are located at both ends of the cylindrical diameter as viewed from the tip side TS, and are located at the same position in the axial direction SD. When the hollow needle 101 according to the comparative example configured in this manner is inserted into a puncture target 99, the puncture resistance increases as the puncture position moves toward the base side BS, and reaches a maximum at the position of the two concave bottoms 13. In the hollow needle 101 according to the comparative example, two concave bottoms 13 appear simultaneously in the axial direction SD, and the puncture resistance of the two concave bottoms 13 is simultaneously applied to the puncture target 99. Therefore, although there is only one peak of puncture resistance, the value is greater than the maximum value of the hollow needle 1 according to the present embodiment shown in FIG. 8A.

As explained above, with the hollow needle 1 according to this embodiment, all of the concave bottoms 13 are formed at different positions in the axial direction SD, so the puncture resistance is distributed according to the number of concave bottoms 13, and the maximum value of the puncture resistance can be suppressed. Furthermore, because the cutting edge 12 has a U-shaped curved shape, stress concentration on the concave bottoms 13 in the hollow needle 1 can be suppressed. Furthermore, when viewed from the tip side TS in the axial direction SD, the first concave bottom 13A and the fourth concave bottom 13D are positioned opposite each other with the center G in between, and the second concave bottom 13B and the third concave bottom 13C are positioned opposite each other with the center G in between, so that imbalance in the circumferential direction PD can be suppressed during puncture.

In the above explanation, the hollow needle 1 is formed in a cylindrical shape (i.e., the shape in the cross section perpendicular to the axis 9 is circular), but it may also have a cylindrical shape other than a cylindrical shape, for example, the shape in the cross section perpendicular to the axis 9 is elliptical.

In the above explanation, when viewed from the tip side TS in the axial direction SD, the first concave bottom 13A and the fourth concave bottom 13D are positioned opposite each other across the center G, and the second concave bottom 13B and the third concave bottom 13C are positioned opposite each other across the center G. However, instead of this arrangement, when viewed from the tip side TS in the axial direction SD, the first concave bottom 13A and the second concave bottom 13B may be positioned opposite each other across the center G, and the third concave bottom 13C and the fourth concave bottom 13D may be positioned opposite each other across the center G.

The above-described written content and illustrations are a detailed explanation of the parts related to the technology of the present disclosure and are merely an example of the technology of the present disclosure. For example, the above explanation of the configuration, functions, actions, and effects is an explanation of an example of the configuration, functions, actions, and effects of the parts related to the technology of the present disclosure. Therefore, it goes without saying that unnecessary parts may be deleted, new elements may be added, or substitutions may be made to the above-described written content and illustrations, as long as they do not deviate from the spirit of the technology of the present disclosure. Furthermore, in order to avoid confusion and to facilitate understanding of the parts related to the technology of the present disclosure, the above-described written content and illustrations omit explanations of common technical knowledge that do not require particular explanation to enable the implementation of the technology of the present disclosure.

In this specification, "A and/or B" is synonymous with "at least one of A and B." In other words, "A and/or B" means that it could be just A, just B, or a combination of A and B. Furthermore, in this specification, the same concept as "A and/or B" applies when three or more things are expressed connected by "and/or."

The disclosure of Japanese Patent Application No. 2024-057947, filed on March 29, 2024, is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.
The use of nouns and similar referents used in connection with the description of the present invention (particularly in connection with the claims that follow) shall be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The words "comprises,""having," and "including" shall be construed as open-ended terms (i.e., meaning "including, but not limited to") unless otherwise noted.

The following additional notes are further disclosed regarding the above embodiment.
(Appendix 1)
A medical hollow needle having a cylindrical shape with a needle tip formed on the distal end side,
When a direction along the axis of the cylindrical shape extending from the tip side to the base end side opposite to the tip side is defined as an axial direction, and a direction along the circumference of the cylindrical shape is defined as a circumferential direction,
The needle tip has three or more pointed portions formed at intervals in the circumferential direction on the tip side, and cutting edges recessed toward the base end side are formed between each of the three or more pointed portions, and the recessed bottom portions located closest to the base end side of each of the three or more cutting edges are formed at different positions in the axial direction.
Medical hollow needle.
According to the configuration of Appendix 1, the puncture resistance when the needle tip pierces the target is distributed according to the number of concave bottoms, so the maximum puncture resistance can be suppressed and the puncture burden can be reduced.
(Appendix 2)
The cutting edge has a U-shaped curved shape.
2. The medical hollow needle according to claim 1.
According to the configuration of Supplementary Note 2, it is possible to suppress the concentration of stress on the recessed bottom portion.
(Appendix 3)
The distance between the recessed bottom portions adjacent to each other in the axial direction is equal to or greater than the thickness of the puncture target.
A medical hollow needle according to claim 1 or 2.
According to the configuration of Appendix 3, a single cutting blade can completely penetrate the thick part of the object to be punctured (such as the wall of a blood vessel), and the puncture resistance can be appropriately distributed.
(Appendix 4)
When the hollow needle is viewed in the axial direction from the tip side, and imaginary lines are drawn extending radially from the center of gravity of the circumference of the cylindrical shape to each of the three or more concave bottom portions, the angle Θx formed by adjacent imaginary lines is given by the following equation, where A is the number of concave bottom portions, B is the inner diameter of the cylindrical shape of the hollow needle, C is the axial distance between adjacent concave bottom portions in the axial direction, and θ is the inclination angle with respect to the axis of the surface of the cutting blade that cuts from the inner surface to the outer surface of the hollow needle at the concave bottom portion:
Arccos {1-(C×tanθ/(B/2))}≦Θx
The range is
A medical hollow needle according to any one of claims 1 to 3.
According to the configuration of Supplementary Note 4, it is possible to ensure appropriate spacing between the concave bottoms in the circumferential direction of the hollow needle, and it is possible to prevent the occurrence of areas where the puncture resistance increases excessively. Furthermore, because the spacing between each of the three or more tips that puncture the target does not become too narrow, rotation around the axis is suppressed, allowing for stable puncture.
(Appendix 5)
the three or more concave bottom portions include a first concave bottom portion, a second concave bottom portion, a third concave bottom portion, and a fourth concave bottom portion, which appear in order when viewed in the axial direction from the tip side to the base end side;
When the hollow needle is viewed from the tip side in the axial direction, the first concave bottom portion and the second concave bottom portion are arranged at positions facing each other across the center of gravity of the circumference of the cylindrical shape, and the third concave bottom portion and the fourth concave bottom portion are arranged at positions facing each other across the center of gravity, or the first concave bottom portion and the fourth concave bottom portion are arranged at positions facing each other across the center of gravity, and the second concave bottom portion and the third concave bottom portion are arranged at positions facing each other across the center of gravity.
A medical hollow needle according to any one of claims 1 to 4.
According to the configuration of Supplementary Note 5, it is possible to prevent the end face of the hollow needle from becoming unbalanced in the circumferential direction when puncturing the target.
(Appendix 6)
The inclination angle θ of the cutting edge surface cut from the inner surface toward the outer surface of the hollow needle at the concave bottom portion relative to the axis is expressed as follows, where A is the number of concave bottom portions, B is the inner diameter of the cylindrical shape of the hollow needle, and C is the axial distance between adjacent concave bottom portions in the axial direction:
θ≦Arctan {((B/(A-1))/C}
fulfill,
A medical hollow needle according to any one of claims 1 to 5.
According to the configuration of Supplementary Note 6, it is possible to ensure the spacing in the axial direction of the recessed bottom portion.

Claims (6)

A medical hollow needle having a cylindrical shape with a needle tip formed on the distal end side,
When a direction along the axis of the cylindrical shape extending from the tip side to the base end side opposite to the tip side is defined as an axial direction, and a direction along the circumference of the cylindrical shape is defined as a circumferential direction,
The needle tip has three or more pointed portions formed at intervals in the circumferential direction on the distal end side, and cutting blades recessed toward the base end side are formed between each of the three or more pointed portions, and the recessed bottoms located closest to the base end side of each of the three or more cutting blades are formed at different positions in the axial direction.
Medical hollow needle. The cutting edge has a U-shaped curved shape.
The medical hollow needle according to claim 1. The distance between adjacent recessed bottom portions in the axial direction is equal to or greater than the thickness of the puncture target.
The medical hollow needle according to claim 1. When the hollow needle is viewed in the axial direction from the tip side, if imaginary lines are drawn extending radially from the center of gravity of the circumference of the cylindrical shape to each of the three or more concave bottom portions, the angle Θx formed by adjacent imaginary lines is given by the following equation, where A is the number of concave bottom portions, B is the inner diameter of the cylindrical shape of the hollow needle, C is the axial distance between adjacent concave bottom portions in the axial direction, and θ is the inclination angle with respect to the axis of the surface of the cutting blade that cuts from the inner surface to the outer surface of the hollow needle at the concave bottom portion:
Arccos {1-(C×tanθ/(B/2))}≦Θx
The range is
The medical hollow needle according to claim 1. the three or more concave bottom portions include a first concave bottom portion, a second concave bottom portion, a third concave bottom portion, and a fourth concave bottom portion, which appear in order when viewed in the axial direction from the distal end side to the proximal end side;
When the hollow needle is viewed in the axial direction from the tip side, the first concave bottom portion and the second concave bottom portion are arranged at positions facing each other across the center of gravity of the circumference of the cylindrical shape, and the third concave bottom portion and the fourth concave bottom portion are arranged at positions facing each other across the center of gravity, or the first concave bottom portion and the fourth concave bottom portion are arranged at positions facing each other across the center of gravity, and the second concave bottom portion and the third concave bottom portion are arranged at positions facing each other across the center of gravity.
The medical hollow needle according to claim 1. The inclination angle θ of the cutting edge surface cut from the inner surface toward the outer surface of the hollow needle at the concave bottom portion relative to the axis is expressed as follows, where A is the number of concave bottom portions, B is the inner diameter of the cylindrical shape of the hollow needle, and C is the axial distance between adjacent concave bottom portions in the axial direction:
θ≦Arctan {((B/(A-1))/C}
fulfill,
The medical hollow needle according to claim 1.