Medical instrument

Abstract

[PROBLEM] To improve the operability of a guide wire. [SOLUTION] A guide wire 1 comprises a body 20 and a distal end tip 40 provided at the distal end of the body 20. The body 20 includes: a first section 21 which is adjacent to the distal end tip 40 and the outer circumference of which is covered by a first resin film 50; and a second section 22 which is located closer to the base end side than the first section 21 and the outer circumference of which is covered by a second resin film 60. The distal end 50d of the first resin film is located closer to the base end side than the distal end 40d of the distal end tip 40. The outer circumference of the second resin film 60 is covered by the first resin film 50.

Description

Medical device

[0001] The present disclosure relates to a medical device.

[0002] As an instrument for guiding a catheter or the like to a stenosis or occlusion (hereinafter referred to as a lesion) formed in a blood vessel, bile duct, pancreatic duct, etc., a guide wire is known. The guide wire disclosed in Patent Document 1 includes a main body portion made of a coil body, and the outer periphery of the main body portion is partially covered with a resin layer.

[0003] Japanese Patent Application Laid-Open No. 2024-102621

[0004] There is room for improvement in the operability of the guide wire disclosed in Patent Document 1.

[0005] The medical device according to the present disclosure includes a main body portion and a tip chip provided at the tip of the main body portion. The main body portion includes a first section adjacent to the tip chip and having an outer periphery covered with a first resin film, and a second section located on the rear end side of the first section and having an outer periphery covered with a second resin film. The tip of the first resin film is located on the rear end side of the tip of the tip chip, and the outer periphery of the second resin film is covered with the first resin film.

[0006] It is a plan view showing a guide wire according to a first embodiment of the present disclosure. It is a cross-sectional view showing an enlarged tip portion of the guide wire according to the first embodiment of the present disclosure. It is a cross-sectional view showing a state in which a curved shape is imparted to the guide wire shown in FIG. 2. It is a schematic view showing an example of a state in which the guide wire is curved into a loop shape. It is a cross-sectional view showing an enlarged tip portion of the guide wire according to a second embodiment of the present disclosure. It is a cross-sectional view showing an enlarged tip portion of the guide wire according to a third embodiment of the present disclosure. It is a cross-sectional view showing an enlarged tip portion of the guide wire according to a fourth embodiment of the present disclosure. It is a cross-sectional view showing an enlarged tip portion of the guide wire according to a fifth embodiment of the present disclosure. It is a cross-sectional view showing an enlarged tip portion of the guide wire according to a sixth embodiment of the present disclosure.

[0007] [First Embodiment] A guidewire 1 according to the first embodiment of the present disclosure will be described with reference to Figures 1 to 4. The guidewire is a medical device. In Figures 1 and 2, the left side is the tip end (distal end), and the right side is the posterior end (proximal end). The guidewire 1 is inserted into a blood vessel, bile duct, pancreatic duct, etc. from the tip end, and the posterior end is manipulated by a surgeon such as a physician.

[0008] Figure 1 is a plan view showing the guidewire 1. As shown in Figure 1, the guidewire 1 comprises a core shaft 10, a main body 20, and a tip 40. The guidewire 1 is used, for example, to guide a catheter (not shown) to a lesion formed in a blood vessel, bile duct, pancreatic duct, etc.

[0009] The core shaft 10 is formed from, for example, stainless steel, a superelastic material, etc. Examples of stainless steel include SUS304 and SUS316. Examples of superelastic materials include Ni-Ti alloy. When the core shaft 10 is formed from a superelastic material, the core shaft 10 has superelastic properties.

[0010] In Figure 1, the core shaft 10 is a solid member. The core shaft 10 may also be a hollow member (for example, a tube).

[0011] The rear end of the main body portion 20 is joined to the core shaft 10 via a brazed portion 25. Figure 2 is a cross-sectional view showing an enlarged view of the tip of the guide wire 1. As shown in Figure 2, the main body portion 20 is hollow. The core shaft 10 is provided inside the main body portion 20. In this embodiment, the main body portion 20 is a coil body formed by winding strands of wire in a spiral shape.

[0012] The material used to make up the main body 20 can be, for example, stainless steel, a superelastic material, or a radiopaque metal. For example, SUS304 and SUS316 can be used as stainless steel. For a superelastic material, a Ni-Ti alloy can be used. For a radiopaque metal, gold, platinum, tungsten, or alloys made of these elements can be used. If the main body 20 is made of a radiopaque metal, the operator can determine the position of the main body 20 under a radioscopic image.

[0013] An inner coil body 30 is provided between the main body 20 and the core shaft 10. The rear end of the inner coil body 30 is joined to the core shaft 10 via a brazing joint 35. The inner coil body 30 may be formed from the same material as the material forming the main body 20.

[0014] The tip 40 is provided at the tip 20d of the main body 20, and the tip 20d of the main body 20 is fixed to the core shaft 10 and the inner coil body 30. The tip 40 is formed in a substantially hemispherical shape. The rear end 40p of the tip 40 is provided further rear than the tip 20d of the main body 20. The tip 40 is formed from, for example, brazing material or metal solder. As brazing material, for example, aluminum alloy brazing material, silver brazing material, or gold brazing material can be used. As metal solder, for example, Au-Sn alloy or Sn-Ag alloy can be used.

[0015] Figure 3 is a schematic cross-sectional view showing the guidewire 1 shown in Figure 2 with a curved shape imparted to it. The curved shape is imparted to the guidewire 1 in advance by causing plastic deformation in the core shaft 10. The pre-imparted curved shape is also called a "pre-shape". The curved shape may be imparted to the guidewire 1 during manufacturing, or it may be imparted to the guidewire 1 by a surgeon before inserting the guidewire 1 into the body. In Figure 3, a guidewire 1 with a pre-imparted curved shape such that the bending angle α is approximately 30° is shown. The bending angle α of the curved shape is not limited to 30°.

[0016] The guidewire 1 may be bent into a loop shape (for example, a U-shape or a J-shape) inside the body so that its tip 40 faces the posterior end. Figure 4 is a schematic diagram showing an example of the guidewire 1 bent into a loop shape. Bending the guidewire 1 into a loop shape is also called "loop formation." Loop formation is performed inside the body. Specifically, loop formation is performed by bending the guidewire 1 by advancing the posterior end of the guidewire 1 in the direction of travel while the tip of the guidewire 1 is in contact with the wall surface of a blood vessel, bile duct, pancreatic duct, etc., and not moving.

[0017] The rigidity of the guide wire 1 decreases from the rear end towards the front end. Since the front end of the guide wire 1 is flexible, the looped guide wire 1 can be returned to its original shape (either a straight shape or a pre-applied curved shape) by utilizing the elasticity of the core shaft 10.

[0018] When the guidewire 1 is advanced in the direction of travel while maintaining its loop shape, the outer circumference of the guidewire 1 will come into contact with the wall surface of blood vessels, bile ducts, pancreatic ducts, etc. Therefore, it is preferable that the coefficient of friction on the outer circumference of the guidewire 1 be small. When forming a loop, if the tip of the guidewire 1 slides along the wall surface of blood vessels, bile ducts, pancreatic ducts, etc., the curvature of the guidewire 1 will not progress. Therefore, it is preferable that the coefficient of friction at the tip of the guidewire 1 be large.

[0019] Therefore, in the guide wire 1, the coefficient of friction at the tip of the guide wire 1 is made greater than the coefficient of friction at the outer circumference of the main body 20, and the outer circumference of the main body 20 is formed as a smooth surface without any steps.

[0020] Specifically, in the guide wire 1, a first resin film 50 is provided on the outer circumference of the main body portion 20, and the outer circumference of the guide wire 1 is covered by the first resin film 50. The tip 50d of the first resin film 50 is provided on the rear end 40p of the tip 40. The first resin film 50 may be formed from multiple layers of resin (for example, three layers of resin). In this case, the innermost layer is preferably made of a resin with high affinity to the material forming the main body portion 20, so that the first resin film 50 is less likely to peel off from the main body portion 20. The first resin film 50 can be made of a hydrophobic resin material, a hydrophilic resin material, or a mixture thereof. For example, hydrophilic resin materials include starch-based materials such as carboxymethyl starch, cellulose-based materials such as carboxymethylcellulose, polysaccharides such as alginic acid, chitin, chitosan, and hyaluronic acid, natural water-soluble polymers such as gelatin, and synthetic water-soluble polymers such as polyvinyl alcohol, polyethylene oxide, polyethylene glycol, polypropylene glycol, polyvinylpyrrolidone, and water-soluble nylon. For example, hydrophobic resin materials include polyurethane, polyethylene, polyvinyl chloride, polyester, polypropylene, polyamide, polystyrene, polyolefin elastomer, polyester elastomer, polyamide elastomer, polyurethane elastomer, etc. It is preferable that the first resin film 50 is formed from a hydrophilic resin. By having hydrophilic properties, the coefficient of friction of the first resin film 50 can be made smaller.

[0021] The tip 40 is not covered by the first resin film 50 and is exposed. In other words, the tip 50d of the first resin film 50 is located further back than the tip 40d of the tip 40, and the tip surface of the guidewire 1 is formed by the tip 40, not the first resin film 50. The coefficient of friction of the surface of the tip 40 is greater than that of the first resin film 50. Therefore, the coefficient of friction of the tip of the guidewire 1 is greater than the coefficient of friction of the outer circumference further back than the tip of the guidewire 1. Consequently, the tip of the guidewire 1 is less likely to slip on the walls of blood vessels, bile ducts, pancreatic ducts, etc., making loop formation easier, while the outer circumference of the guidewire 1 is more likely to slip on the walls of blood vessels, bile ducts, pancreatic ducts, etc. Therefore, the surgeon can easily advance the guidewire 1 in the direction of travel while maintaining its loop shape.

[0022] In addition, because the coefficient of friction of the tip 40 is greater than that of the first resin film 50, the resistance that the guide wire 1 experiences inside the lesion increases, making it easier to select the route of the guide wire 1 inside the lesion.

[0023] The guide wire 1 includes a second resin film 60 covering the outer circumference of the main body 20. The second resin film 60 may be made of a hydrophilic resin. The second resin film 60 may be made of a hydrophobic resin. The second resin film 60 may be made of the same resin as the resin that forms the first resin film 50.

[0024] The second resin film 60 is provided on the outer circumference of the main body 20 at a distance from the tip 40. In other words, the main body 20 includes a first section 21 whose outer circumference is covered by the first resin film 50, and a second section 22 whose outer circumference is covered by the second resin film 60. The first section 21 is adjacent to the tip 40, and the second section 22 is located further back than the first section 21. The second resin film 60 is provided only on the outer circumference of the second section 22, and not on the outer circumference of the first section 21. The outer circumference of the second resin film 60 is covered by the first resin film 50.

[0025] The outer circumference of the second section 22 is covered with a second resin film 60. The outer circumference of the second resin film 60 is covered with a first resin film 50. Therefore, compared to the case where the outer circumference of the second section 22 is directly covered with the first resin film 50, the irregularities of the second section 22 (irregularities of the coil body) are less likely to be visible on the first resin film 50. Consequently, the outer circumference of the guide wire 1 can be made smoother, and the frictional resistance of the outer circumference of the guide wire 1 can be reduced. As a result, the guide wire 1 can be advanced more easily in the direction of travel while maintaining its loop shape.

[0026] Rather than the second section 22 being adjacent to the tip 40, the first section 21 is adjacent to the tip 40, and the second section 22 is located at the rear end of the first section 21. As a result, the coefficient of friction on the outer circumference of the guidewire 1 changes gradually in the longitudinal direction, allowing the guidewire 1 to easily advance through the body. Because the outer diameter of the guidewire 1 changes gradually, it is possible to suppress the guidewire 1 from getting caught inside the body.

[0027] The thickness of the second resin film 60 is greater than that of the first resin film 50. Therefore, the irregularities of the second section 22 (irregularities of the coil body) are less likely to be visible due to the first resin film 50. Consequently, the coefficient of friction on the outer circumference of the guide wire 1 can be reduced. As a result, the surgeon can more easily advance the guide wire 1 in the direction of travel while maintaining its loop shape.

[0028] Only the first resin film 50 is provided on the outer circumference of the first section 21 of the main body 20, and the second resin film 60 is not provided. Therefore, the bending rigidity of the first section 21 is smaller compared to the case where both the first resin film 50 and the second resin film 60 are provided on the outer circumference of the first section 21. Consequently, the first section 21 can be easily bent when forming a loop, making loop formation easier.

[0029] By covering the second resin film 60 with the first resin film 50, it is possible to prevent the second resin film 60 from peeling off from the main body 20 or getting caught on the walls of blood vessels, bile ducts, pancreatic ducts, etc. Therefore, the surgeon can easily advance the guidewire 1 inside blood vessels, bile ducts, pancreatic ducts, etc.

[0030] Thus, the guide wire 1 allows for easy loop formation and easy advancement in the direction of travel. Therefore, the operability of the guide wire 1 can be improved.

[0031] The core shaft 10 preferably has superelastic properties. In this case, even if a larger strain is applied to the core shaft 10 during loop formation, the loop-shaped guide wire 1 can be more easily returned to its original shape (either a straight shape or a pre-formed curved shape).

[0032] The second resin film 60 includes a tapered portion 61 that decreases in diameter towards the tip. The first resin film 50 covering the outer circumference of the second resin film 60 also includes a tapered portion 51. Therefore, the outer diameter of the guidewire 1 changes gradually in the longitudinal direction, eliminating sharp corners on the outer circumference of the guidewire 1. This prevents the guidewire 1 from getting caught on the lesion. When a surgeon transports a treatment device such as a catheter or stent (not shown) along the guidewire 1, it prevents the treatment device from getting caught on the guidewire 1.

[0033] When the guide wire 1 is pre-curved, it is preferable that the core shaft 10 is curved inside the first section 21 of the main body 20, as shown in Figure 3, and that the first section 21 is curved. The pre-curved first section 21 makes it easier to curve during loop formation. Therefore, loop formation becomes easier.

[0034] [Second Embodiment] Next, a guide wire 2 according to the second embodiment will be described with reference to Figure 5. Figure 5 is an enlarged cross-sectional view showing the tip of the guide wire 2. The difference from the guide wire 1 shown in Figure 2 is that in the guide wire 1, the tip 50d of the first resin film 50 is located at the rear end 40p of the tip tip 40, whereas in the guide wire 2, as shown in Figure 5, the tip 50d of the first resin film 50 is provided between the tip 40d and the rear end 40p of the tip tip 40. The guide wire 2 also provides the same effects as the guide wire 1.

[0035] [Third Embodiment] Next, a guide wire 3 according to the third embodiment will be described with reference to Figure 6. Figure 6 is an enlarged cross-sectional view showing the tip of the guide wire 3. The difference from the guide wire 1 shown in Figure 2 is that in the guide wire 1, the tip 50d of the first resin film 50 is located at the rear end 40p of the tip tip 40, whereas, as shown in Figure 6, in the guide wire 3, the tip 50d of the first resin film 50 is provided further rear than the rear end 40p of the tip tip 40. The guide wire 3 also provides the same effects as the guide wire 1.

[0036] [Fourth Embodiment] Next, a guide wire 4 according to the fourth embodiment will be described with reference to Figure 7. Figure 7 is an enlarged cross-sectional view showing the tip of the guide wire 4. To explain the difference from the guide wire 1 shown in Figure 2, in the guide wire 1, the tip 50d of the first resin film 50 is located at the rear end 40p of the tip tip 40, whereas, as shown in Figure 7, in the guide wire 4, the tip 50d of the first resin film 50 is provided between the tip 20d of the main body 20 and the rear end 40p of the tip tip 40. To explain the difference from the guide wire 2 shown in Figure 5, in the guide wire 2, the tip 50d of the first resin film 50 is provided on the tip side of the main body 20, whereas, as shown in Figure 7, in the guide wire 4, the tip 50d of the first resin film 50 is provided on the rear end side of the tip 20d of the main body 20. To explain the difference from the guide wire 3 shown in Figure 6, in the guide wire 3, the tip 50d of the first resin film 50 is located further back than the rear end 40p of the tip tip 40, whereas in the guide wire 4, as shown in Figure 7, the tip 50d of the first resin film 50 is located further forward than the rear end 40p of the tip tip 40. In other words, in the guide wire 4, the tip 50d of the first resin film 50 is located between the tip 20d of the main body 20 and the rear end 40p of the tip tip 40. The guide wire 4 also produces the same effect as the guide wire 1.

[0037] [Fifth Embodiment] Next, a guide wire 5 according to the fifth embodiment will be described with reference to Figure 8. Figure 8 is an enlarged cross-sectional view showing the tip of the guide wire 5. The differences from the guide wires 1 to 4 shown in Figures 2, 5 to 7 are that in guide wires 1 to 4, the outer diameter of the core shaft 10 is constant, whereas as shown in Figure 8, guide wire 5 has a core shaft 510 with an outer diameter that is not constant. The tip 540 of guide wire 2 differs from the tip 40 of guide wires 1 to 4 shown in Figures 2, 5 to 7 in that it includes a tapered shape.

[0038] The core shaft 510 has a small diameter portion 511 and a large diameter portion 512 whose outer diameter is larger than that of the small diameter portion 511. The small diameter portion 511 is fixed to the tip 540. The large diameter portion 512 is located at the rear end of the small diameter portion 511. The boundary portion 513 between the small diameter portion 511 and the large diameter portion 512 has a tapered shape that decreases in diameter towards the tip.

[0039] The core shaft 510 has different rigidity in the longitudinal direction. In this embodiment, the rigidity of the large-diameter portion 512 is greater than that of the small-diameter portion 511. As a result, the rigidity of the core shaft 510 on the rear end side of the boundary portion 513 is greater than that of the core shaft 510 on the front end side of the boundary portion 513. Therefore, when forming a loop, the small-diameter portion 511 can be curved, and displacement of the loop shape towards the rear end side of the boundary portion 513 can be suppressed.

[0040] The boundary portion 513 is provided between the tip 61d and the rear end 61p of the tapered portion 61 of the second resin film 60. In other words, only the small-diameter portion 511 is located inside the first section 21 of the main body portion 20, and the large-diameter portion 512 is not located there. Therefore, the bending rigidity of the second section 22 is greater than that of the first section 21, and displacement of the loop shape toward the rear end beyond the boundary portion 513 can be suppressed.

[0041] The tip 540 includes an enlarged diameter portion 541 that widens toward the tip, a reduced diameter portion 542 that narrows toward the tip, and a rounded head portion 543 toward the tip. The enlarged diameter portion 541 is adjacent to the first section 21 of the main body portion 20. The reduced diameter portion 542 is located toward the tip than the enlarged diameter portion 541. The head portion 543 is located toward the tip than the reduced diameter portion 542, and the head portion 543 forms the tip of the guide wire 5.

[0042] The reduced-diameter portion 542 has a tapered shape in which the outer diameter decreases conically toward the tip side. By reducing the area of the tip 540 that contacts the lesion, the pressure exerted by the tip 540 on the lesion can be increased. Further, when the tip 540 enters the lesion, the lesion is expanded by the tapered shape. Therefore, the tip 540 is likely to catch on the lesion, facilitating the rerouting of the guide wire 5 or the technique of guiding the guide wire 5 from the false lumen to the true lumen (reentry).

[0043] The tip 540 may not include the expanded-diameter portion 541. The tip 540 may be such that the reduced-diameter portion 542 is adjacent to the first section 21 of the main body 20. Instead of the expanded-diameter portion 541, the tip 540 may include a portion with a constant outer diameter.

[0044] [Sixth Embodiment] Next, the guide wire 6 according to the sixth embodiment will be described while referring to FIG. 9. FIG. 9 is a cross-sectional view showing an enlarged tip portion of the guide wire 6. To explain the difference from the guide wire 5 shown in FIG. 8, in the guide wire 5, the boundary portion 513 of the core shaft 510 is provided between the front end 61d and the rear end 61p of the tapered portion 61 of the second resin film 60, whereas, as shown in FIG. 9, in the guide wire 6, the boundary portion 513 is provided on the rear end side with respect to the rear end 61p of the tapered portion 61. The guide wire 6 also has the same effect as the guide wire 5.

[0045] As described above, the embodiments of the present disclosure have been explained. The present disclosure is not limited to the above-described embodiments, and can be appropriately modified without departing from the spirit of the present disclosure.

[0046] For example, the guide wires 1 to 6 may not include the core shafts 10 and 510. In this case, it is sufficient that the main body 20 has the same rigidity as the core shafts 10 and 510.

[0047] The guide wires 1 to 4 (see FIGS. 2, 5 to 7) may be provided with a tip chip 540 shown in FIGS. 8 and 9 instead of the tip chip 40. Similarly, the guide wires 5 and 6 (see FIGS. 8 and 9) may be provided with a tip chip 40 shown in FIGS. 2, 5 to 7 instead of the tip chip 540.

[0048] In the guide wires 1 to 6, the rear end of the inner coil body 30 and the brazing portion 35 are located inside the second section 22. The present disclosure is not limited to this form. That is, the rear end of the inner coil body 30 and the brazing portion 35 may be located inside the first section 21.

[0049] The guide wires 1 to 6 may not include the inner coil body 30.

Claims

1. A medical device (1, 2, 3, 4, 5, 6) comprising a main body (20) and tip tips (40, 540) provided at the tip of the main body (20), wherein the main body (20) includes a first section (21) adjacent to the tip tips (40, 540) and whose outer circumference is covered by a first resin film (50), and a second section (22) located further rear than the first section (21) and whose outer circumference is covered by a second resin film (60), wherein the tip (50d) of the first resin film (50) is located further rear than the tip (40d) of the tip tips (40, 540), and the outer circumference of the second resin film (60) is covered by the first resin film (50).

2. The medical device according to claim 1 (1, 2, 3, 4, 5, 6), wherein the first resin film (50) is formed from a hydrophilic resin.

3. The medical device according to claim 1 or 2 (2, 4), wherein the tip (50d) of the first resin film (50) is provided between the tip (40d) and the rear end (40p) of the tip tip (40).

4. The medical device (3) according to claim 1 or 2, wherein the tip (50d) of the first resin film (50) is provided on the rear end side of the rear end (40p) of the tip (40).

5. The medical device according to any one of claims 1 to 3 (1, 2, 3, 4, 5, 6), wherein the tip (50d) of the first resin film (50) is provided on the rear end side of the tip (20d) of the main body (20).

6. The medical device (5, 6) according to any one of claims 1 to 5, wherein the tip (540) includes a tapered shape that decreases in diameter toward the tip side.

7. The medical device according to any one of claims 1 to 6, wherein the main body (20) is hollow and further comprises a core shaft (10, 510) provided inside the main body (20).

8. The medical device according to claim 7 (1, 2, 3, 4, 5, 6), wherein the core shaft (10, 510) has superelastic properties.

9. The medical device according to claim 7 or 8 (5, 6), wherein the core shaft (510) has a small diameter portion (511) and a large diameter portion (512) provided at the rear end of the small diameter portion (511), the large diameter portion (512) having an outer diameter greater than the outer diameter of the small diameter portion (511), and the boundary portion (513) between the small diameter portion (511) and the large diameter portion (512) is located inside the second section (22).

10. The medical device according to any one of claims 1 to 9, wherein the second resin film (60) includes a tapered portion (61) that decreases in diameter toward the tip.

11. The medical device (5) according to claim 9, wherein the second resin film (60) includes a tapered portion (61) that decreases in diameter toward the tip, and the boundary portion (513) is provided between the tip (61d) and the rear end (61p) of the tapered portion (61).

12. The medical device (6) according to claim 9, wherein the second resin film (60) includes a tapered portion (61) that decreases in diameter toward the tip, and the boundary portion (513) is provided on the rear end side of the rear end (61p) of the tapered portion (61).

13. The medical device (1) according to any one of claims 1 to 12, wherein the first section (21) is curved.

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