Needle catheter

Abstract

This needle catheter comprises: a hollow puncture needle having a needle tip section and a needle base section positioned closer to the base side than the needle tip and having an outer diameter smaller than that of the needle tip section; a hollow shaft part having a shaft tip section and a shaft base section positioned closer to the base side than the shaft tip section; and an overlap part formed by inserting the needle base section into the shaft tip section. In the overlap part, the needle base section and the shaft tip section are joined by a first resin member positioned between the outer peripheral surface of the needle base section and the inner peripheral surface of the shaft tip section. The rigidity of the overlap part is lower than the rigidity of the needle tip section, but higher than the rigidity of the shaft base section.

Description

needle catheter

[0001] The present disclosure relates to needle catheters.

[0002] Catheters equipped with hollow puncture needles are known. For example, Patent Document 1 discloses a catheter / needle assembly having an epidural needle, an elongated tubular portion sized to fit into the hole of the epidural needle, and an elongated needle portion fitted into and fixed in the hole of the tubular portion. Hereinafter, catheters equipped with puncture needles, such as those disclosed in Patent Document 1, will also be referred to as "needle catheters."

[0003] Incidentally, a known regenerative therapy method for regenerating cardiomyocytes whose function has been impaired by myocardial infarction or other conditions involves preparing cardiomyocytes in a sheet form outside the body and attaching the cell sheet to the heart to promote cardiomyocyte regeneration (see, for example, Patent Document 2). However, because the heart is constantly beating, it is difficult to stably attach a cell sheet to the heart for an extended period of time. Therefore, a therapeutic method that promotes cardiomyocyte regeneration by injecting a medicinal solution into cardiomyocytes is anticipated. This therapeutic method will hereinafter be referred to as "medicinal solution injection therapy." In medicinal solution injection therapy, a medicinal solution prepared by culturing and inducing differentiation of stem cells is injected into the myocardium via the coronary artery.

[0004] Japanese Patent Application Publication No. 7-524 Patent No. 5572138

[0005] In the above-described drug solution injection therapy, the needle catheter described in Patent Document 1 can be used to inject drug solution into the myocardium from the coronary artery. After the needle is inserted into the myocardium to inject drug solution, when the needle is withdrawn from the myocardium, it is necessary to prevent the needle (needle portion) from falling off from the shaft portion (tube portion) of the catheter from a safety standpoint. In this regard, the needle catheter described in Patent Document 1 leaves room for improvement.

[0006] These problems are not limited to drug injection therapy, but are common to all percutaneous procedures using needle catheters, including those inserted into the body lumen, such as the lymphatic system, biliary system, urinary system, respiratory system, digestive system, secretory glands, and reproductive organs, as well as the vascular system.

[0007] The present disclosure has been made to solve at least some of the above-mentioned problems, and aims to provide a needle catheter that contributes to improving the safety of procedures involving puncturing body tissue.

[0008] The present disclosure has been made to solve at least part of the above-mentioned problems, and can be realized in the following aspects.

[0009] (1) According to one aspect of the present disclosure, there is provided a needle catheter comprising: a hollow puncture needle having a needle tip portion and a needle base portion located proximally of the needle tip portion and having a smaller outer diameter than the needle tip portion; a hollow shaft portion having a shaft tip portion and a shaft base portion located proximally of the shaft tip portion; and an overlap portion formed by inserting the needle base portion into the shaft tip portion, wherein the overlap portion joins the needle base portion and the shaft tip portion with a first resin member disposed between an outer circumferential surface of the needle base portion and an inner circumferential surface of the shaft tip portion, and the rigidity of the overlap portion is smaller than that of the needle tip portion and greater than that of the shaft base portion.

[0010] According to this configuration, the needle catheter has an overlap portion formed by inserting the needle base end into the shaft tip end, and the needle base end and the shaft tip end are joined at this overlap portion by a first resin member disposed between the outer circumferential surface of the needle base end and the inner circumferential surface of the shaft tip end. This allows for a strong connection between the puncture needle and the shaft portion, preventing the puncture needle from falling off the shaft portion when withdrawing it from the body tissue during a procedure involving puncturing the body tissue. The rigidity of the overlap portion is smaller than that of the needle tip end but greater than that of the shaft base end, allowing for a gradual change in the rigidity of the needle catheter. This prevents stress concentration during puncture with the puncture needle and reduces the occurrence of kinking due to stress concentration. As a result, the needle catheter of this configuration improves the safety of procedures involving puncturing body tissue.

[0011] (2) In the needle catheter of the above embodiment, the distal end surface of the shaft distal end portion and the outer circumferential surface of the needle distal end portion may be joined together. With this configuration, in addition to the joining of the outer circumferential surface of the needle base end portion and the inner circumferential surface of the shaft distal end portion (i.e., joining by the first resin member), the distal end surface of the shaft distal end portion and the outer circumferential surface of the needle distal end portion are also joined together, which allows for an even stronger joining of the puncture needle and the shaft portion, and further prevents the puncture needle from falling off the shaft portion when withdrawing it from body tissue in a procedure involving puncturing body tissue.

[0012] (3) In the needle catheter of the above embodiment, the shaft portion may include a hollow coil body having a coil body distal portion and a coil body proximal portion located proximally of the coil body distal portion, and the shaft distal portion may include the coil body distal portion, and the shaft proximal portion may include the coil body proximal portion. With this configuration, since the shaft portion includes a hollow coil body, the flexibility of the entire shaft portion, including the overlap portion, can be improved, and the rotational compliance of the needle catheter can also be improved. Rotational compliance is also called torque transmission. As a result, the needle catheter can be easily advanced even in curved blood vessels, thereby improving the efficiency of the procedure.

[0013] (4) In the needle catheter of the above embodiment, the shaft portion may further include a hollow resin tube disposed on the inner circumferential surface of the coil body and extending from the distal end of the coil body to the proximal end of the coil body, wherein the needle base end and the resin tube are joined at the overlap portion by the first resin member disposed between the outer circumferential surface of the needle base end and the inner circumferential surface of the resin tube, and the resin tube and the distal end of the coil body are joined by a second resin member disposed between the outer circumferential surface of the resin tube and the inner circumferential surface of the distal end of the coil body. According to this configuration, the shaft portion includes, in addition to the coil body, a resin tube disposed on the inner circumferential surface of the coil body, thereby maintaining flexibility of the entire shaft portion, including the overlap portion, and preventing leakage of the medicinal solution from gaps in the coil body to the outside. Because the outer circumferential surface of the resin tube and the inner circumferential surface of the distal end of the coil body are joined (i.e., joined by the second resin member), relative rotation of the coil body with respect to the resin tube is prevented, thereby preventing damage to the resin tube. As a result, the safety and efficiency of procedures involving puncture of body tissue can be improved.

[0014] (5) In the needle catheter of the above embodiment, the proximal end of the coil body and the resin tube may not be joined at least in part of the proximal end of the coil body. According to this configuration, the proximal end of the coil body and the resin tube are not joined at least in part of the proximal end of the coil body. This improves the flexibility of the shaft portion compared to when the proximal end of the coil body and the resin tube are joined entirely.

[0015] (6) In the needle catheter of the above embodiment, the puncture needle and the coil body may both be made of metal, and a weld may be formed between the distal end surface of the coil body distal end and the outer circumferential surface of the needle distal end. With this configuration, the metal puncture needle and the metal coil body are also joined by a strong weld. This further improves the joining strength between the coil body and the puncture needle, and further prevents the puncture needle from falling off the shaft during the procedure.

[0016] (7) The needle catheter of the above embodiment may further include a radiopaque marker provided on the outer circumferential surface of the needle tip. According to this configuration, the radiopaque marker provided on the outer circumferential surface of the needle tip allows the surgeon to easily grasp the position of the puncture needle under X-ray images. X-ray images are also called angio images.

[0017] The present disclosure can be realized in various forms, for example, in the form of a puncture needle, a needle catheter having a puncture needle, a puncture needle system including a needle catheter and a combination device, and methods of manufacturing these.

[0018] 1 is an explanatory diagram illustrating the configuration of a needle catheter. FIG. 1 is an enlarged longitudinal cross-sectional view of the boundary between the puncture needle and the first shaft portion. FIG. 2 is an enlarged longitudinal cross-sectional view of the boundary between the first shaft portion and the second shaft portion. FIG. 3 is an enlarged longitudinal cross-sectional view of the boundary between the second shaft portion and the connector. FIG. 4 is an explanatory diagram showing the state of the heart. FIG. 5 is an explanatory diagram showing the state of advancing the needle catheter within a blood vessel. FIG. 6 is an explanatory diagram showing the state of puncturing myocardium using the needle catheter. FIG. 7 is an enlarged longitudinal cross-sectional view of the boundary between the puncture needle and the first shaft portion in a needle catheter of a second embodiment. FIG. 8 is an enlarged longitudinal cross-sectional view of the boundary between the first shaft portion and the second shaft portion in a needle catheter of a second embodiment. FIG. 9 is an enlarged longitudinal cross-sectional view of the boundary between the puncture needle and the first shaft portion in a needle catheter of a third embodiment. FIG. 10 is an enlarged longitudinal cross-sectional view of the boundary between the first shaft portion and the second shaft portion in the needle catheter of the third embodiment. FIG. 11 is an explanatory diagram illustrating the configuration of a needle catheter of a fourth embodiment. FIG. 12 is an enlarged longitudinal cross-sectional view of the boundary between the second shaft portion and the connector of a modified example.

[0019] First Embodiment Fig. 1 is an explanatory diagram illustrating the configuration of a needle catheter 2. The needle catheter 2 is inserted into a body lumen, such as the vascular system, lymphatic system, biliary system, urinary system, respiratory system, digestive system, secretory glands, and reproductive organs, and is used to inject a liquid into body tissue. Hereinafter, a medicinal solution injection therapy will be illustrated as an example of a specific application of the needle catheter 2. The medicinal solution injection therapy is a treatment method that promotes the regeneration of cardiomyocytes by injecting a medicinal solution into cardiomyocytes. In this medicinal solution injection therapy, a medicinal solution prepared by culturing and inducing differentiation of stem cells is injected into the myocardium via a coronary artery.

[0020] For ease of explanation, Figure 1 includes some components whose relative size ratios differ from the actual size. Some components are exaggerated. Figure 1 illustrates mutually orthogonal X, Y, and Z axes. The X axis corresponds to the longitudinal direction of the needle catheter 2, the Y axis corresponds to the height direction of the needle catheter 2, and the Z axis corresponds to the width direction of the needle catheter 2. The left side of Figure 1 (-X axis direction) is referred to as the "distal side" of the needle catheter 2 and each component, and the right side of Figure 1 (+X axis direction) is referred to as the "proximal side" of the needle catheter 2 and each component. Of the ends of the needle catheter 2 and each component in the longitudinal direction (X axis direction), the end located on the distal side is referred to as the "distal end," and the other end located on the proximal side is referred to as the "proximal end." The distal end and its vicinity are referred to as the "distal portion," and the proximal end and its vicinity are referred to as the "proximal end." The distal end is inserted into the living body, and the proximal end is manipulated by a surgeon, such as a doctor. These points are also common to Figure 2 and subsequent figures.

[0021] The needle catheter 2 includes a puncture needle 21, a first shaft portion 22, a second shaft portion 23, a marker 24, and a connector 29. The needle catheter 2 of this embodiment is a single-lumen catheter having one needle. As shown by dashed lines in FIG. 1 , the puncture needle 21, the first shaft portion 22, the second shaft portion 23, and the connector 29 are formed with lumens 2L that connect the interiors of each portion along the longitudinal direction of the needle catheter 2. The lumen 2L is a lumen through which a medicinal solution flows. The distal end of the lumen 2L communicates with the outside through a distal end opening 2a. The proximal end of the lumen 2L communicates with the outside through a proximal end opening 2b. In the example of FIG. 1 , the longitudinal length of the first shaft portion 22 and the longitudinal length of the second shaft portion 23 are approximately equal.

[0022] The puncture needle 21 is a hollow needle attached to the tip of the first shaft portion 22. The puncture needle 21 is also simply called a "needle." The puncture needle 21 has an outer diameter that gradually decreases from the base end toward the tip, and the tip has a sharp shape to facilitate puncturing body tissue. The puncture needle 21 is curved in one specific direction (the -Y axis direction in the illustrated example). A tip opening 2a is formed at the tip of the puncture needle 21. The tip opening 2a is an opening used to discharge the medicinal solution when the medicinal solution is injected using the needle catheter 2.

[0023] FIG. 2 is an enlarged longitudinal cross-sectional view of the boundary area CA between the puncture needle 21 and the first shaft portion 22. As shown in FIG. 2, the puncture needle 21 has a needle tip portion 211 and a needle base portion 212. The needle tip portion 211 is the portion of the puncture needle 21 having the thickest outer diameter Φ211. Therefore, the needle tip portion 211 does not include the sharp portion at the tip of the puncture needle 21. The needle base portion 212 is a portion that is continuous with the needle tip portion 211 on the proximal side of the needle tip portion 211. The needle base portion 212 has an outer diameter Φ212 that is smaller than that of the needle tip portion 211. Such a puncture needle 21 can be formed by processing the outer periphery of a portion of the proximal side of a needle with a sharp tip, thereby thinning the thickness of the needle at the proximal side. At least one of polishing and swaging can be used for the processing. The polishing may be physical polishing or chemical polishing. In the example of Fig. 2, a step 213 is formed at the boundary between the needle tip portion 211 and the needle base portion 212 due to the reduction in outer diameter. However, the step 213 does not have to be present. If the step 213 is not present, the boundary between the needle tip portion 211 and the needle base portion 212 may be tapered.

[0024] The first shaft portion 22 has a coil body 221 and a resin tube 222 and has a hollow tubular shape as a whole. In this embodiment, the coil body 221 and the resin tube 222 are the "shaft portion." As shown in FIG. 2 , the first shaft portion 22 has a shaft distal end portion 11 and a shaft proximal end portion 12. The shaft distal end portion 11 is a portion on the distal side of the first shaft portion 22, and the shaft distal end portion 11 covers the needle proximal end portion 212 of the puncture needle 21. In other words, the needle proximal end portion 212 of the puncture needle 21 is the portion inserted into the shaft distal end portion 11 of the first shaft portion 22. The shaft proximal end portion 12 is a portion that is continuous with the shaft distal end portion 11 and is located proximally of the shaft distal end portion 11. The puncture needle 21 is not inserted inside the shaft proximal end portion 12.

[0025] Thus, the portion of the boundary area CA between the puncture needle 21 and the first shaft section 22 where the needle base end 212 of the puncture needle 21 is inserted into the shaft tip section 11 of the first shaft section 22 is also referred to as the "overlap section." In the example of FIG. 2 , the overlap section is equal to the section where the shaft tip section 11 is provided. In the overlap section, the needle base end section 212 and the shaft tip section 11 are joined by a first resin member 223 arranged between the outer circumferential surface of the needle base end section 212 and the inner circumferential surface of the shaft tip section 11. In other words, the first resin member 223 is arranged between the needle base end section 212 and the shaft tip section 11 in the radial direction of the needle catheter 2.

[0026] The rigidity of the needle catheter 2 in the overlapping portion (i.e., the section where the shaft distal end 11 is provided) is smaller than the rigidity of the needle distal end 211, but larger than the rigidity of the needle catheter 2 in the shaft proximal end 12. That is, the rigidity of the needle catheter 2 in Figure 2 is such that the section indicated by reference numeral 12 < the section indicated by reference numeral 11 < the section indicated by reference numeral 211. The rigidity can be calculated by a three-point bending test. The marker 24 has a short length in the longitudinal direction, so it can be ignored when considering the difference in rigidity.

[0027] The coil body 221 of the first shaft portion 22 improves the flexibility and rotational compliance of the intermediate portion of the needle catheter 2 (the portion between the puncture needle 21 and the second shaft portion 23). Rotational compliance is also called torque transmission capability. The coil body 221 is a hollow, cylindrical coil having an elongated outer shape, and is a multi-strand coil formed by winding multiple strands of wires. The coil body 221 may be a single-strand coil formed by winding a single strand of wire. The coil body 221 may be a single-strand strand coil formed by winding a strand of wire obtained by twisting multiple strands of wires together. The coil body 221 may be a multi-strand strand coil formed by using multiple strands of wires twisted together and winding each strand of wire together.

[0028] The tip of the coil body 221 is located at the boundary between the needle distal end portion 211 and the needle proximal end portion 212, in other words, at the position of the step 213. The proximal end of the coil body 221 is located slightly proximal to the tip of the second shaft portion 23 ( FIG. 3 ). As shown in FIG. 2 , the coil body 221 has a coil body distal end portion 2211 and a coil body proximal end portion 2212. The coil body distal end portion 2211 is a portion on the distal side of the coil body 221, and the coil body distal end portion 2211 covers the needle proximal end portion 212 of the puncture needle 21. In other words, it can be said that the shaft distal end portion 11 described above includes the coil body distal end portion 2211. The coil body proximal end portion 2212 is a portion that is provided proximally of the coil body distal end portion 2211 and is continuous with the coil body distal end portion 2211. In other words, it can be said that the shaft proximal end portion 12 described above includes the coil body proximal end portion 2212.

[0029] As shown in FIG. 2 , the distal end surface 2210 of the coil body 221 and the outer circumferential surface of the needle distal end portion 211 are joined by a joint 225. In other words, the distal end surface 2210 of the coil body 221 is the distal end surface of the shaft distal end portion 11 and the distal end surface of the coil body distal end portion 2211. The joint 225 can be formed using any bonding agent, for example, a metal solder such as silver solder, gold solder, zinc, an Sn—Ag alloy, or an Au—Sn alloy. As described below, the coil body 221 and the puncture needle 21 are both made of metal. The joint 225 firmly joins the coil body 221 and the puncture needle 21 by welding them together, which are made of metal, or by welding them together using a metal solder. The joint 225 is a "welded portion." The outer diameter Φ22 of the coil body 221 is larger than the outer diameter Φ211 of the needle tip portion 211. The outer diameter Φ22 of the coil body 221 is synonymous with the outer diameter of the first shaft portion 22.

[0030] The resin tube 222 of the first shaft portion 22 prevents the medicinal solution in the lumen 2L from leaking out through gaps in the coil body 221. The resin tube 222 is a hollow, cylindrical member (tubular body) having an elongated outer shape and is disposed on the inner circumferential surface side of the coil body 221. The distal end of the resin tube 222 is located at the same position as the distal end of the coil body 221. The proximal end of the resin tube 222 extends proximally beyond the proximal end of the coil body 221 and into the connector 29. In other words, the resin tube 222 extends from the distal end 2211 of the coil body to the proximal end 2212 of the coil body. In this embodiment, the terms "same" and "equal" are not limited to exact coincidence but also mean allowing for differences due to manufacturing errors and the like. "Constant" is synonymous with "approximately constant" and means being approximately constant while allowing for variations due to manufacturing errors and the like.

[0031] In the overlapping portion (i.e., the section where the shaft tip portion 11 is provided), the above-mentioned first resin member 223 is specifically disposed between the outer circumferential surface of the needle base end portion 212 and the inner circumferential surface of the resin tube 222, joining the needle base end portion 212 and the resin tube 222. In other words, the first resin member 223 is disposed between the needle base end portion 212 and the resin tube 222 in the radial direction of the needle catheter 2. Furthermore, in the overlapping portion, the resin tube 222 and the coil body tip portion 2211 are joined by the second resin member 224 disposed between the outer circumferential surface of the resin tube 222 and the inner circumferential surface of the coil body tip portion 2211. In other words, the second resin member 224 is disposed between the resin tube 222 and the coil body tip portion 2211 in the radial direction of the needle catheter 2. In the example of Figure 2, the second resin member 224 extends slightly toward the base end from the base end of the coil body tip portion 2211, and is also provided at the tip portion of the coil body base end portion 2212 (specifically, the tip portion 12a of the shaft base end portion 12).

[0032] In the intermediate portion of the shaft base end 12 excluding the tip end 12 a and the base end 12 b, the coil body 221 (specifically, the coil body base end 2212) is not joined to the resin tube 222, and a space SP is present between the coil body 221 and the resin tube 222. In other words, in the example of this embodiment, the coil body base end 2212 and the resin tube 222 are not joined to each other in a portion of the coil body base end 2212.

[0033] The rigidity of the needle catheter 2 at the distal end 12a of the shaft proximal end 12 is greater than the rigidity of the needle catheter 2 at the shaft proximal end 12 excluding the distal end 12a and the proximal end 12b (FIG. 3). That is, the rigidity of the needle catheter 2 in FIG. 2 is as follows: section 12 (excluding section 12a) < section 12a < section 11 < section 211.

[0034] The marker 24 functions as a mark to enable confirmation of the position of the puncture needle 21 under X-ray images. X-ray images are also called angiographic images. The marker 24 is a radiopaque, annular member. As shown in FIG. 2 , the marker 24 is provided on the outer circumferential surface of the needle tip portion 211, in a position close to the tip of the joint 225. In other words, the marker 24 is provided on the base end side of the needle tip portion 211, in the vicinity of the boundary between the needle tip portion 211 and the needle base portion 212 (specifically, the step 213), and covers the outer circumferential surface of the needle tip portion 211. The marker 24 may have any shape other than an annular shape, or may be omitted.

[0035] The tip resin member 220 is a member for gradually changing the outer diameters of the first shaft portion 22 and the puncture needle 21 by filling in the step caused by the difference between the outer diameter Φ22 of the first shaft portion 22 and the outer diameter Φ211 of the needle tip portion 211. The tip resin member 220 covers the joint portion 225 and the marker 24, and has an outer diameter that gradually decreases from the base end side toward the tip end side. The tip of the tip resin member 220 is located closer to the tip end than the tip of the marker 24, and the base end of the tip resin member 220 is at the same position as the base end of the joint portion 225. The base end of the tip resin member 220 may be located closer to the base end than the base end of the joint portion 225.

[0036] Fig. 3 is an enlarged longitudinal cross-sectional view of a boundary portion CB between the first shaft portion 22 and the second shaft portion 23. Fig. 4 is an enlarged longitudinal cross-sectional view of a boundary portion CC between the second shaft portion 23 and the connector 29. As shown in Fig. 3, the second shaft portion 23 has a pipe 231 and a resin tube 222, and has a hollow tubular shape as a whole. In this embodiment, the "second shaft portion 23" is a collective term for the pipe 231 and the resin tube 222.

[0037] The pipe 231 of the second shaft portion 23 improves the rigidity of the proximal end of the needle catheter 2 (i.e., the portion closer to the proximal end than the first shaft portion 22) and improves the pushability of the needle catheter 2. The pipe 231 is a hollow cylindrical tubular body with an elongated outer shape. As shown in Figure 3, the pipe 231 has an outer diameter Φ23 that is larger than the outer diameter Φ22 of the first shaft portion 22.

[0038] The distal end of the pipe 231 covers the proximal end of the coil body 221 (specifically, the proximal end 2212 of the coil body). In other words, at the boundary between the first shaft portion 22 and the second shaft portion 23, the outer peripheral surface of the coil body 221 and the inner peripheral surface of the pipe 231 are in contact. The pipe 231 and the coil body 221 may be joined at the distal end surface 231a of the pipe 231 (shown in a dashed circle in FIG. 3). For example, any bonding agent, such as silver solder, gold solder, zinc, a Sn—Ag alloy, or a Au—Sn alloy, may be used for the joining. A third resin member 226 is disposed at the boundary between the first shaft portion 22 and the second shaft portion 23.

[0039] The third resin member 226 is a member that joins the first shaft portion 22 and the second shaft portion 23 by joining the coil body 221, the pipe 231, and the resin tube 222. The third resin member 226 is disposed between the outer peripheral surface of the resin tube 222 and the inner peripheral surfaces of the coil body 221 and the pipe 231. The distal end of the third resin member 226 is located at a position on the distal end side of the coil body proximal end portion 2212 of the coil body 221 relative to the distal end surface 231a of the pipe 231. The proximal end of the third resin member 226 is located at a position on the proximal side of the coil body 221 relative to the proximal end of the coil body 221. In other words, the third resin member 226 is provided at the overlapping portion between the pipe 231 and the coil body 221 and portions on both ends thereof. In FIG. 3 , the portion of the shaft proximal end portion 12 where the third resin member 226 is provided is also referred to as the proximal end portion 12b of the shaft proximal end portion 12.

[0040] As shown in Fig. 4, the base end of the pipe 231 is inserted inside the tip end of the connector 29. As shown in Fig. 4, the base end of the resin tube 222 extends further to the base end side than the base end of the pipe 231 inside the connector 29. A fourth resin member 227 is arranged at the boundary between the second shaft portion 23 and the connector 29.

[0041] The fourth resin member 227 is a member that joins the second shaft portion 23 and the connector 29 by joining the connector 29, the pipe 231, and the resin tube 222. The fourth resin member 227 is disposed between the outer circumferential surface of the resin tube 222 and the inner circumferential surface of the connector 29. As shown in the figure, the base end of the resin tube 222 is located closer to the base end than the base end of the pipe 231. Therefore, the fourth resin member 227 covers the inner and outer circumferential surfaces of the pipe 231 between the resin tube 222 and the connector 29, fixing them together. In this way, the base end of the resin tube 222 extends closer to the base end than the base end of the pipe 231 and is fixed by the fourth resin member 227, thereby further suppressing leakage of the medicinal solution from the lumen 2L.

[0042] In the middle portion of the second shaft portion 23 where the third resin member 226 and the fourth resin member 227 are not provided, the pipe 231 and the resin tube 222 are not joined, and a space SP is formed between the pipe 231 and the resin tube 222. In other words, in the example of the present embodiment, the pipe 231 and the resin tube 222 are not joined in a part of the second shaft portion 23 (specifically, the pipe 231).

[0043] The connector 29 is attached to the proximal end side of the second shaft portion 23 to make it easier for the surgeon to grasp the device. As shown in Figures 1 and 4, the connector 29 is a substantially cylindrical member provided with a pair of wings. A proximal end opening 2b is formed at the proximal end of the connector 29 (Figure 1). The proximal end opening 2b is an opening used to attach a syringe for supplying a medicinal solution when injecting the medicinal solution through the needle catheter 2.

[0044] The puncture needle 21 can be formed from a metal with shape memory properties, such as a nickel-titanium alloy or a CuZnAl alloy. The coil body 221 can be formed from at least one of a stainless steel alloy, a superelastic alloy, a radiolucent alloy, and a radiopaque alloy. Examples of stainless steel alloys include SUS304 and SUS316. Examples of superelastic alloys include a nickel-titanium alloy. Examples of radiolucent alloys include piano wire, nickel-chromium alloys, and cobalt alloys. Examples of radiopaque alloys include gold, platinum, tungsten, and alloys containing these elements (e.g., platinum-stainless steel alloys and platinum-nickel alloys). The coil body 221 may also be formed from known materials other than those mentioned above. The resin tube 222 can be formed from a resin with excellent chemical resistance, such as a polyimide resin. The pipe 231 can be formed from known materials such as a stainless steel alloy or a superelastic alloy. Examples of stainless steel alloys include SUS 302, SUS 304, and SUS 316. Examples of superelastic alloys include nickel-titanium alloys.

[0045] The tip resin member 220, the first resin member 223, the second resin member 224, the third resin member 226, and the fourth resin member 227 can be formed using an adhesive such as a cyanoacrylic adhesive or an epoxy adhesive. At least a portion of the tip and the first to fourth resin members 220, 223, 224, 226, and 227 may be formed using an adhesive with good biocompatibility. The marker 24 can be formed from a radiopaque resin material or metal material. The connector 29 can be formed from a well-known resin material.

[0046] Fig. 5 is an explanatory diagram showing the state of the heart. Fig. 6 is an explanatory diagram showing the state of advancing the needle catheter 2 within a blood vessel. Fig. 7 is an explanatory diagram showing the state of puncturing a myocardium 96 using the needle catheter 2. In this embodiment, an example is shown in which a medicinal solution is injected into the myocardium 96 from the left coronary artery 94 of the heart 90. Fig. 5 shows the heart 90, and the guiding catheter 4, delivery catheter 1, and needle catheter 2 inserted into the heart 90. Figs. 6 and 7 show the delivery catheter 1 and needle catheter 2 within the left coronary artery 94. For ease of explanation, in Figs. 6 and 7, the guiding catheter 4 is represented by a dashed line and the delivery catheter 1 is represented by a solid line.

[0047] The surgeon can perform the procedure for drug solution injection therapy, for example, by following the steps a1 to a7 below. (a1) The surgeon inserts a work horse wire from the upper arm or thigh and delivers it to the entrance of the left coronary artery 94. The work horse wire is a guide wire used for delivery. (a2) The surgeon inserts the work horse wire from the tip of the guiding catheter 4 and delivers the guiding catheter 4 along the work horse wire to the entrance of the left coronary artery 94. (a3) ​​The surgeon inserts the work horse wire into the delivery catheter 1. The surgeon pushes the delivery catheter 1 along the work horse wire inside the guiding catheter 4. In this way, by using the guiding catheter 4, the delivery catheter 1 is guided to the entrance of the left coronary artery 94. (a4) The surgeon further pushes the delivery catheter 1 into the left coronary artery 94 and delivers it until the side opening 1c of the delivery catheter 1 reaches a position in the left coronary artery 94 near the injection site of the drug solution. At this time, the surgeon adjusts the circumferential orientation of the delivery catheter 1 so that the side opening 1c of the delivery catheter 1 is positioned on the side of the myocardium 96, as shown in Figure 6. Then, the surgeon removes the workpiece wire from the delivery catheter 1. (a5) The surgeon inserts the needle catheter 2 into the delivery catheter 1. At this time, the surgeon gently curves the puncture needle 21 of the needle catheter 2 until the length of the puncture needle 21 in the curved direction (-Y axis direction in Figure 1) is equal to or less than the inner diameter of the delivery catheter 1. The surgeon then pushes the needle catheter 2 toward the tip inside the delivery catheter 1. Figure 6 shows the state of the needle catheter 2 in step a5. (a6) The surgeon pushes the needle catheter 2 forward, causing the puncture needle 21 of the needle catheter 2 to protrude from the side opening 1c of the delivery catheter 1. Then, the curved shape of the puncture needle 21 of the needle catheter 2 returns to its original shape. Thereafter, when the surgeon pushes the needle catheter 2 in, the puncture needle 21 of the needle catheter 2 can puncture the myocardium 96. Figure 7 shows the state of the needle catheter 2 in step a6. (a7) The surgeon attaches a syringe filled with a medicinal solution to the proximal end opening 2b of the needle catheter 2 and supplies the medicinal solution from the syringe to the lumen 2L.The medicinal liquid passes through the lumen 2L and is discharged from the distal end opening 2a into the myocardium 96. This allows the medicinal liquid to be injected into the injection site (i.e., the region of the body tissue to be punctured).

[0048] As described above, according to the first embodiment, the needle catheter 2 has an overlap portion (FIG. 2: reference numeral 11) formed by inserting the needle base end portion 212 into the shaft distal end portion 11. At this overlap portion, the needle base end portion 212 and the shaft distal end portion 11 are joined by a first resin member 223 disposed between the outer circumferential surface of the needle base end portion 212 and the inner circumferential surface of the shaft distal end portion 11. This allows the puncture needle 21 and the first shaft portion 22 to be firmly joined, preventing the puncture needle 21 from falling off the first shaft portion 22 when withdrawing it from the body tissue in a procedure involving puncturing the body tissue, as shown in FIGS. 5 to 7 . The first shaft portion 22 is a shaft portion. The rigidity of the overlap portion (FIG. 2: reference numeral 11) is smaller than the rigidity of the needle distal end portion 211 but greater than the rigidity of the shaft proximal end portion 12, thereby achieving a gradual change in the rigidity of the needle catheter 2. Therefore, stress concentration can be suppressed when the puncture needle 21 is inserted, and the occurrence of kinking due to stress concentration can be suppressed. As a result, the needle catheter 2 of the first embodiment can improve the safety of procedures involving puncture of body tissue.

[0049] According to the needle catheter 2 of the first embodiment, in addition to the joining of the outer circumferential surface of the needle base end 212 to the inner circumferential surface of the shaft distal end portion 11 (specifically, joining by the first resin member 223), the distal end surface 2210 of the shaft distal end portion 11 is also joined to the outer circumferential surface of the needle distal end portion 211 ( FIG. 2 : joint 225). This allows for an even stronger joining of the puncture needle 21 to the first shaft portion 22, and in procedures involving puncturing body tissue, it is possible to further prevent the puncture needle 21 from falling off the first shaft portion 22 when the puncture needle 21 is pulled out of the body tissue.

[0050] Furthermore, according to the needle catheter 2 of the first embodiment, the first shaft portion 22 includes a hollow coil body 221. This improves the flexibility of the entire first shaft portion 22, including the overlap portion (FIG. 2: reference numeral 11), and also improves the rotational followability, or torque transmission, of the needle catheter 2. As a result, the needle catheter 2 can be easily advanced even in curved blood vessels, thereby improving the efficiency of the procedure.

[0051] Furthermore, according to the needle catheter 2 of the first embodiment, the first shaft portion 22 includes, in addition to the coil body 221, a resin tube 222 disposed on the inner circumferential surface of the coil body 221. This prevents leakage of the medicinal solution from gaps in the coil body 221 while maintaining the flexibility of the entire first shaft portion 22, including the overlap portion (FIG. 2: reference numeral 11). The outer circumferential surface of the resin tube 222 and the inner circumferential surface of the coil body distal end portion 2211 are joined (specifically, joined by the second resin member 224). This prevents the coil body 221 from rotating relative to the resin tube 222, thereby preventing damage to the resin tube 222, for example, when the surgeon rotates the needle catheter 2. This improves the safety and efficiency of procedures involving puncturing body tissue.

[0052] Furthermore, according to the needle catheter 2 of the first embodiment, the coil body proximal end 2212 is not joined to the resin tube 222 at least in part of the coil body proximal end 2212 (FIG. 2: gap SP), which improves the flexibility of the first shaft portion 22 compared to when the coil body proximal end 2212 and the resin tube 222 are entirely joined.

[0053] Furthermore, according to the needle catheter 2 of the first embodiment, the metal puncture needle 21 and the metal coil body 221 are joined by a joint 225 in addition to the first resin member 223 and the second resin member 224, which are disposed on either side of the resin tube 222. The joint 225 is a welded portion. The joint 225 is strong because the metal puncture needle 21 and the coil body 221 are welded together by welding or metal solder. Therefore, according to the needle catheter 2 of the first embodiment, the bond strength between the coil body 221 and the puncture needle 21 can be further improved compared to a configuration in which the puncture needle and the coil body are joined together by welding alone or a configuration in which the puncture needle and the coil body are joined together by a resin member alone. As a result, the puncture needle 21 can be more effectively prevented from falling off the shaft portion during the procedure.

[0054] Furthermore, according to the needle catheter 2 of the first embodiment, since it is provided with a radiopaque marker 24 provided on the outer surface of the needle tip 211, the surgeon can easily grasp the position of the puncture needle 21 under X-ray images.

[0055] Second Embodiment Fig. 8 is an enlarged longitudinal cross-sectional view of a boundary portion CA between the puncture needle 21 and the first shaft portion 22A in a needle catheter 2A of a second embodiment. Fig. 9 is an enlarged longitudinal cross-sectional view of a boundary portion CB between the first shaft portion 22A and the second shaft portion 23A in a needle catheter 2A of the second embodiment. In the second embodiment, an example will be described in which the configurations of the first shaft portion 22A and the second shaft portion 23A are different from those in the first embodiment.

[0056] The needle catheter 2A of the second embodiment has the same configuration as that described in the first embodiment, except that it includes a first shaft portion 22A instead of the first shaft portion 22 and a second shaft portion 23A instead of the second shaft portion 23. The first shaft portion 22A has a hollow tubular pipe 221A and does not include the resin tube 222 described in the first embodiment. In the second embodiment, the pipe 221A is the "shaft portion." The second shaft portion 23A has a hollow tubular pipe 231A and does not include the resin tube 222 described in the first embodiment. Hereinafter, for the sake of distinction, the pipe 221A will also be referred to as the first pipe 221A, and the pipe 231A will also be referred to as the second pipe 231A. As shown in FIG. 9 , the outer diameter Φ22A of the first pipe 221A and the outer diameter Φ23A of the second pipe 231A are the same. Both outer diameters Φ22A and Φ23A are larger than the outer diameter Φ212 of the needle base portion 212. The first pipe 221A can be made of, for example, the same material as the pipe 231 described in the first embodiment or a well-known resin material. The second pipe 231A can be made of the same material as the pipe 231 described in the first embodiment.

[0057] As shown in FIG. 8 , the needle catheter 2A has a shaft distal end portion 11A that covers the needle proximal end portion 212 of the puncture needle 21, and a shaft proximal end portion 12A that is located proximal to the shaft distal end portion 11A. In the needle catheter 2A, the portion where the needle proximal end portion 212 of the puncture needle 21 is inserted into the shaft distal end portion 11A of the first shaft portion 22A is the overlap portion. In the overlap portion, a first resin member 223A is disposed between the outer circumferential surface of the needle proximal end portion 212 and the inner circumferential surface of the shaft distal end portion 11A (specifically, the inner circumferential surface of the first pipe 221A). This first resin member 223A joins the needle proximal end portion 212 and the shaft distal end portion 11A (specifically, the first pipe 221A). A joint portion 225 is provided on the distal end surface 2210A of the first pipe 221A. As shown in FIG. 8, the needle catheter 2A does not have the second resin member 224 described in the first embodiment.

[0058] As shown in FIG. 9 , in the needle catheter 2A, the proximal end of the first shaft portion 22A (specifically, the proximal end surface of the first pipe 221A) and the distal end of the second shaft portion 23A (specifically, the distal end surface 231aA of the second pipe 231A) are butt-joined to each other. Any bonding agent, such as silver solder, gold solder, zinc, Sn—Ag alloy, or Au—Sn alloy, can be used for the bonding. As shown in FIG. 9 , the needle catheter 2A does not have the third resin member 226 described in the first embodiment. The proximal end of the second pipe 231A is inserted into the connector 29 and is joined by a fourth resin member disposed between the outer circumferential surface of the second pipe 231A and the inner circumferential surface of the connector 29. The rigidity of each section of the needle catheter 2A is as described in the first embodiment.

[0059] As described above, the configuration of the first shaft portion 22A and the second shaft portion 23A can be modified in various ways, and may be configured without using a coil body or a resin tube. In the configuration described in the second embodiment, a resin tube or a coating layer may be provided inside the first pipe 221A and the second pipe 231A to suppress leakage of the medicinal solution. In the configuration described in the second embodiment, the first pipe 221A and the second pipe 231A may be configured as a single pipe. The needle catheter 2A of the second embodiment described above can also achieve the same effects as the first embodiment described above. According to the needle catheter 2A of the second embodiment, the configuration of the needle catheter 2A can be simplified, the manufacturing cost of the needle catheter 2A can be reduced, and the diameter of the needle catheter 2A can be made smaller.

[0060] <Third embodiment> Figure 10 is an enlarged longitudinal cross-sectional view of a boundary portion CA between the puncture needle 21 and the first shaft portion 22B in a needle catheter 2B of a third embodiment. Figure 11 is an enlarged longitudinal cross-sectional view of a boundary portion CB between the first shaft portion 22B and the second shaft portion 23B in a needle catheter 2B of the third embodiment. In the third embodiment, an example will be described in which the gap SP described in the first embodiment is not provided.

[0061] The needle catheter 2B of the third embodiment has the same configuration as that described in the first embodiment, except that it includes a first shaft portion 22B instead of the first shaft portion 22 and a second shaft portion 23B instead of the second shaft portion 23. The first shaft portion 22B and the second shaft portion 23B include a second resin member 224B instead of the second to fourth resin members 224, 226, and 227 described in the first embodiment. The second resin member 224B is a member that joins the coil body 221, the pipe 231, the connector 29, and the resin tube 222. As shown in FIGS. 10 and 11 , the second resin member 224B is disposed between the outer circumferential surface of the resin tube 222 and the inner circumferential surfaces of the coil body 221, the second pipe 231A, and the connector 29. In other words, the second resin member 224B is disposed on the outer circumferential surface of the resin tube 222 over the entire length from the distal end to the proximal end of the resin tube 222, and joins the resin tube 222 to each of the components covering the resin tube 222 (specifically, the coil body 221, the pipe 231, and the connector 29). Therefore, the needle catheter 2B does not have the gap SP described in the first embodiment.

[0062] As described above, the configuration of the needle catheter 2B can be modified in various ways, and the first shaft portion 22B or the second shaft portion 23B may not have a void SP inside. The needle catheter 2B of the third embodiment as described above can also achieve the same effects as the first embodiment. According to the needle catheter 2B of the third embodiment, the first shaft portion 22B and the second shaft portion 23B can be joined more firmly.

[0063] <Fourth embodiment> Figure 12 is an explanatory diagram illustrating the configuration of a needle catheter 2C of a fourth embodiment. In the fourth embodiment, a configuration in which the puncture needle 21C is not curved will be described. The needle catheter 2C of the fourth embodiment has the configuration described in the first embodiment, but includes a puncture needle 21C instead of the puncture needle 21, and does not include a marker 24. The puncture needle 21C does not have a curved outer shape, but is entirely linear.

[0064] As described above, the configuration of the needle catheter 2C can be modified in various ways, and the puncture needle 21C may be straight. Because the puncture needle 21C is formed of a metal with shape-memory properties as described above, the surgeon can deform the puncture needle 21C into a shape that is easier to perform the procedure by squeezing it with their fingers or the like prior to use in the procedure. The surgeon may perform the procedure without bending the puncture needle 21C (leaving it straight). The needle catheter 2C of the fourth embodiment described above can also achieve the same effects as the first embodiment described above. Furthermore, the needle catheter 2C of the fourth embodiment can provide a needle catheter 2C that allows the surgeon to flexibly change the curvature and shape of the puncture needle 21C depending on the surgeon's preferences and the type of procedure.

[0065] <Modifications of this embodiment> The present disclosure is not limited to the above-described embodiment, and can be implemented in various forms without departing from the gist thereof. For example, the following modifications are also possible.

[0066] [Modification 1] In the above first to fourth embodiments, one example of the configuration of the needle catheters 2, 2A to 2C is shown, but the configuration of the needle catheters 2, 2A to 2C can be modified in various ways.

[0067] FIG. 13 is an enlarged longitudinal cross-sectional view of a boundary portion between the second shaft portion 23 and the connector 29 in a modified example. In the first embodiment, an example was described in which the second shaft portion 23 does not include the coil body 221. As shown in FIG. 13 , the second shaft portion 23 may include the coil body 221 in addition to the pipe 231 and the resin tube 222. In this case, the "second shaft portion 23" is a collective term for the pipe 231, the coil body 221, and the resin tube 222. In this case, as shown in FIG. 13 , the proximal end of the pipe 231 is located at the same position as the proximal end of the coil body 221 inside the connector 29. The proximal end of the resin tube 222 extends further proximally than the proximal end of the coil body 221 inside the connector 29. The proximal end of the pipe 231, the proximal end of the coil body 221, and the proximal end of the resin tube 222 may be located at the same position or at different positions inside the connector 29. The fourth resin member 227 joins the connector 29, the pipe 231, the coil body 221, and the resin tube 222 together, thereby joining the second shaft portion 23 and the connector 29. In other words, as shown in Fig. 13, the tube 222, the coil body 221, and the shaft 231 are layered from the inside to the outside of the second shaft portion 23. With this configuration, it is possible to achieve the same effects as the above-described embodiments.

[0068] For example, the needle catheter 2 may not have some of the above-described components, such as the tip resin member 220, the marker 24, and the joint 225. For example, the needle catheter 2 may be provided with a plurality of markers indicating the puncture depth on the puncture needle 21 and a portion of the tip side of the first shaft portion 22. These markers are arranged in a scale pattern at regular intervals. The surgeon can easily grasp the puncture depth by checking these markers under X-ray images.

[0069] For example, in the needle catheter 2, the length of the first shaft portion 22 and the length of the second shaft portion 23 in the longitudinal direction may be different. For example, the length of the first shaft portion 22 may be shorter than the length of the second shaft portion 23. This will further improve the pushability of the needle catheter 2. The length of the first shaft portion 22 may be longer than the length of the second shaft portion 23. This will further improve the flexibility of the needle catheter 2. For example, the outer peripheral surface of the needle catheter 2 may be coated with a hydrophilic resin or a hydrophobic resin. This will improve the slidability of the needle catheter 2 inside the delivery catheter 1. For example, in the needle catheter 2, the inner peripheral surface of the resin tube 222 may be coated with a resin that has excellent chemical resistance.

[0070] 2, the tip of the coil body 221 may extend to the needle tip portion 211. In other words, the tip of the coil body 221 may be located more distal than the tip of the resin tube 222. In further other words, the tip of the coil body 221 may be located more distal than the boundary between the needle tip portion 211 and the needle base portion 212. In FIG. 3, the base end of the coil body 221 may be located at the same position as the tip of the second shaft portion 23.

[0071] [Variation 2] The configurations of the needle catheters 2, 2A to 2C of the first to fourth embodiments and the configuration of the needle catheters 2, 2A to 2C of Variation 1 may be combined as appropriate. For example, the needle catheter 2A described in the second embodiment or the needle catheter 2B described in the third embodiment may be configured to have the puncture needle 21C described in the fourth embodiment. For example, in the needle catheter 2A described in the second embodiment, the base end of the first pipe 221A and the tip end of the second pipe 231A may be overlapped and joined together.

[0072] This aspect has been described above based on embodiments and modifications. The above-described embodiments of the aspect are intended to facilitate understanding of this aspect and are not intended to limit this aspect. This aspect may be modified or improved without departing from the spirit and scope of the claims, and equivalents thereof are included in this aspect. If a technical feature is not described as essential in this specification, it may be deleted as appropriate.

Claims

1. A needle catheter (2, 2A-2C) comprising: a hollow puncture needle (21, 21C) having a needle tip (211) and a needle base (212) located proximal to the needle tip (211) and having a smaller outer diameter than the needle tip (211); a hollow shaft (22, 22A, 22B) having a shaft tip (11, 11A) and a shaft base (12, 12A) located proximal to the shaft tip (11, 11A); and an overlap portion formed when the needle base (212) is inserted into the shaft tip (11, 11A), In the overlap portion, the needle base end portion (212) and the shaft tip portion (11, 11A) are joined by a first resin member (223, 223A) arranged between the outer peripheral surface of the needle base end portion (212) and the inner peripheral surface of the shaft tip portion (11, 11A), and the rigidity of the overlap portion is less than the rigidity of the needle tip portion (211) and greater than the rigidity of the shaft base end portion (12, 12A).

2. A needle catheter (2, 2A to 2C) according to claim 1, wherein the distal end surface of the shaft distal end portion (11, 11A) and the outer circumferential surface of the needle distal end portion (211) are joined.

3. A needle catheter (2, 2B, 2C) according to claim 1 or 2, wherein the shaft portion (22, 22B) includes a hollow coil body (221) having a coil body distal portion (2211) and a coil body proximal portion (2212) located proximal to the coil body distal portion (2211), the shaft distal portion (11) includes the coil body distal portion (2211), and the shaft proximal portion (12) includes the coil body proximal portion (2212).

4. A needle catheter (2, 2B, 2C) according to claim 3, wherein the shaft portion (22, 22B) further includes a hollow resin tube (222) disposed on the inner peripheral side of the coil body (221) and extending from the distal end (2211) of the coil body to the proximal end (2212) of the coil body, and wherein at the overlap portion, the needle proximal end (212) and the resin tube (222) are joined by the first resin member (223) disposed between the outer peripheral surface of the needle proximal end (212) and the inner peripheral surface of the resin tube (222), and the resin tube (222) and the distal end (2211) of the coil body are joined by a second resin member (224, 224B) disposed between the outer peripheral surface of the resin tube (222) and the inner peripheral surface of the distal end (2211) of the coil body.

5. A needle catheter (2, 2C) according to claim 4, wherein the proximal end of the coil body (2212) is not joined to the resin tube (222) in at least a portion of the proximal end of the coil body (2212).

6. A needle catheter (2, 2B, 2C) according to claim 4 or 5, wherein the puncture needle (21, 21C) and the coil body (221) are both made of metal, and a weld (225) is provided between the tip end face of the coil body tip portion (2211) and the outer circumferential surface of the needle tip portion (211).

7. A needle catheter (2, 2A, 2B) according to any one of claims 1 to 6, further comprising a radiopaque marker (24) provided on the outer circumferential surface of the needle tip (211).

Images