Medical-grade long body

Abstract

This invention provides a medical-grade elongated body that exhibits good flexibility in its distal portion, allowing for smooth passage through lesions. [Solution] A medical elongated body having a central axis extending in the longitudinal direction, having a conductive coil and an electrode pair at its distal end, wherein the coil extends in the longitudinal direction while spirally circling the central axis, and the electrode pair generates a shock wave by discharging when a voltage is applied between the electrode pair through the coil.

Description

Technical Field

[0001] The present disclosure relates to a medical elongate body.

Background Art

[0002] There is known a medical elongate body that is used in intravascular lithotripsy (IVL) in percutaneous coronary intervention (PCI) and gives a shock wave from a distal portion to a calcified lesion portion, thereby creating minute cracks in the hardened blood vessel to soften the blood vessel and facilitating subsequent stent expansion (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a medical elongate body as described above, the structure of the electric circuit for generating a shock wave tends to inhibit the flexibility of the distal portion and the passageability of the lesion portion.

[0005] Therefore, an object of the present disclosure is to provide a medical elongate body that can exhibit good passageability of a lesion portion due to good flexibility of the distal portion.

Means for Solving the Problems

[0006] One aspect of the present disclosure is as follows.

[0007] [1] A medical elongate body that extends in a long shape and has a central axis extending in the longitudinal direction, It has a conductive coil and an electrode pair at the distal end. The coil extends in the longitudinal direction while spirally circling the central axis, The electrode pair is a long medical device that generates a shock wave by discharging when a voltage is applied between the electrode pair through the coil.

[0008] [2] A medical elongated body according to [1], comprising the electrode pair and the coil, and having a closed circuit for applying the voltage between the electrode pair.

[0009] [3] The electrode pair is arranged to overlap the coil from the radially outer side, as described in [1] or [2], for the medical elongated body.

[0010] [4] The electrode pair is arranged so as not to overlap radially with respect to the coil, as described in [1] or [2].

[0011] [5] Having a second coil, One electrode of the electrode pair is connected to one end of the coil, The other electrode of the electrode pair is connected to one end of the second coil, a medical elongated body as described in any one of [1] to [4].

[0012] [6] Having a second pair of electrodes, The medical elongated body according to [5], wherein one electrode of the second electrode pair is connected to the other end of the second coil.

[0013] [7] The medical elongated body according to [6], wherein the second coil has a portion disposed between the electrode pair and the second electrode pair in the longitudinal direction.

[0014] [8] A medical elongated body configured as a catheter, as described in any one of items [1] to [7].

[0015] [9] The medical elongate body according to [8], having a balloon covering the electrode pair.

[0016]

[10] The medical elongate body according to any one of [1] to [9], and An activation device that generates an electromotive force in the coil by electromagnetic induction, a medical elongate body system.

Advantages of the Invention

[0017] According to the present disclosure, it is possible to provide a medical elongate body that can exhibit good passage through a lesion due to good flexibility of the distal portion.

Brief Description of the Drawings

[0018] [Figure 1] It is a schematic diagram of a medical elongate body system in an embodiment of the present disclosure. [Figure 2] It is an enlarged view of part A in FIG. 1. [Figure 3] It is a cross-sectional view taken along line B-B in FIG. 2. [Figure 4] It is a schematic diagram showing a first modification of the shock wave generation circuit shown in FIG. 2. [Figure 5] It is a schematic diagram showing a second modification of the shock wave generation circuit shown in FIG. 2.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present disclosure will be exemplified and described in detail with reference to the drawings.

[0020] As shown in FIG. 1, a medical elongate body system 1 according to an embodiment of the present disclosure includes a medical elongate body 2 and an activation device 3.

[0021] The medical elongated body 2 is elongated and has a central axis O that extends in the longitudinal direction. The medical elongated body 2 has an elongated body main body 2a that is inserted into the lumen of blood vessels or other structures in living organisms such as the human body, and an operating part 2b that is connected to the proximal end of the elongated body main body 2a and is operated by the practitioner.

[0022] In this embodiment, the direction from the practitioner's hand towards the living body along the longitudinal direction is called the distal direction, the opposite direction is called the proximal direction, the direction perpendicular to the central axis O is called the radial direction, and the direction that circles the central axis O is called the circumferential direction.

[0023] The medical elongated body 2 is configured as a catheter. The elongated body 2a has a balloon 4 at its distal end. The balloon 4 expands and deforms from a deflated state (shown by a dashed line in Figure 1) to an expanded state (shown by a solid line in Figure 1), allowing for treatments such as expanding a stent within a body cavity. The elongated body 2a has a lumen for liquids such as saline solution that pass through to expand and deform the balloon 4 (not shown), and a lumen for a guidewire (not shown) through which a guidewire passes.

[0024] As shown in Figures 1-3, the elongated body 2a has a conductive coil 5 and, for example, a pair of metal electrodes 6 inside the balloon 4 at its distal end. The coil 5 extends longitudinally while spiraling around the central axis O. The electrode pair 6 generates a shock wave when a voltage is applied between them through the coil 5, causing a discharge (arc discharge). The discharge occurs when the balloon 4 is expanded, and the shock wave is generated by a liquid discharge inside the balloon 4, propagates through the liquid inside the balloon 4, reaches the lesion in the body cavity, and softens the lesion by applying shock. The elongated medical body 2 of this embodiment is particularly suitable for endovascular calcification fragmentation in coronary angioplasty.

[0025] The elongated main body 2a consists of one or more coils 5 and a non-coiled portion 7 made of a material other than the coils 5. The non-coiled portion 7 consists of a balloon 4, one or more electrode pairs 6, and a base material 8 made of a non-conductive material other than the balloon 4 and electrode pairs 6, for example, a resin base material. The coils 5 may be arranged by winding them around the outer surface of the base material 8 as shown in the figure, or they may be embedded in the base material 8. The coils 5 have a conductive core material, for example, made of metal, and an insulating covering material, for example, made of resin, that covers the core material. The electrode pairs 6 are supported by both or either the covering material of the coils 5 and the base material 8.

[0026] The coil 5 has good flexibility. From the viewpoint of obtaining good straightness due to good compressive rigidity, it is preferable that the coil 5 has a tightly wound coil portion (not shown) which is a portion consisting of a single-winding or multi-winding coil where adjacent portions in the longitudinal direction come into contact with each other.

[0027] The electrode pair 6 consists of a cylindrical tubular electrode 6a centered on the central axis O, and an electrode piece 6b positioned at a distance from the tubular electrode 6a. The tubular electrode 6a has a notch 6a1 at one end in the longitudinal direction (the proximal end in this embodiment), and the electrode piece 6b is located within the notch 6a1. The electrode pair 6 is arranged superimposed on the coil 5 from the radially outer side. The coil 5 has an overlapping portion 5a that overlaps the electrode pair 6 radially, and a non-overlapping portion 5b that is offset longitudinally from the electrode pair 6.

[0028] The medical elongated body 2 has a shock wave generating circuit 9 which consists of an electrode pair 6 and a coil 5 and applies a voltage between the electrode pair 6. The shock wave generating circuit 9 is a closed circuit. One electrode of the electrode pair 6 is connected to one end of the coil 5, and the other electrode of the electrode pair 6 is connected to the other end of the coil 5. The cylindrical electrode 6a is connected to one end of the coil 5 via a cylindrical conductor 9a, and the electrode piece 6b is connected to the other end of the coil 5 via a single-sided conductor 9b.

[0029] The activation device 3 generates an electromotive force in the coil 5 of the closed-circuit shock wave generation circuit 9 by electromagnetic induction, applies a voltage between the electrode pair 6, and generates a shock wave due to discharge. The activation device 3 has an electromagnet 3a that generates a magnetic field that causes electromagnetic induction, and a power supply unit 3b that supplies power to the electromagnet 3a to generate the magnetic field. The activation device 3 can generate an electromotive force in the coil 5 by electromagnetic induction by bringing the electromagnet 3a close to the coil 5 located inside the body cavity of the living body from outside the living body and changing the magnetic field inside the coil 5. With a configuration that generates an electromotive force in the coil 5 of the closed-circuit shock wave generation circuit 9 by electromagnetic induction, there is no need for wiring to connect the shock wave generation circuit 9 to an external power source of the medical elongated body 2, thus simplifying the structure and manufacturing process of the medical elongated body 2.

[0030] The elongated main body 2a has a shock wave generating circuit (A) 9A and a shock wave generating circuit (B) 9B. The shock wave generating circuit (A) 9A is composed of a coil (A) 5A, an electrode pair (A) 6A consisting of a cylindrical electrode 6a and an electrode piece 6b, a cylindrical conductor (A) 10A, and a single-sided conductor (A) 11A. The shock wave generating circuit (B) 9B is composed of a coil (B) 5B, an electrode pair (B) 6B consisting of a cylindrical electrode 6a and an electrode piece 6b, a cylindrical conductor (B) 10B (not shown), and a single-sided conductor (B) 11B. The notch 6a1 of the electrode pair (B) 6B is provided so as to be circumferentially offset from the notch 6a1 of the electrode pair (A) 6A.

[0031] According to this embodiment, the shock wave generation circuit 9 is composed of a coil 5 that exhibits good flexibility in the distal portion, thereby providing good passage through the lesion to the medical elongated body 2.

[0032] In this embodiment, the electrode pair 6 is arranged to overlap the coil 5 from the radially outer side, but it is not limited to this configuration. As shown in the first modified example in Figure 4, the electrode pair 6 may be arranged so as not to overlap the coil 5 radially. In the first modified example, the electrode pair 6 is arranged adjacent to the coil 5 in the longitudinal direction and is supported by the base material 8.

[0033] In this embodiment, the shock wave generating circuit 9 is composed of one electrode pair 6 and one coil 5, but it is not limited to this. For example, as shown in the second modified example in Figure 5, the shock wave generating circuit 9 may have a second coil 5 (the coil 5 to the left of the right electrode pair 6 in Figure 5), one electrode of the electrode pair 6 (the right electrode pair 6 in Figure 5) is connected to one end of the coil 5 (the coil 5 to the right of the right electrode pair 6 in Figure 5), and the other electrode of the electrode pair 6 is connected to one end of the second coil 5. With this configuration, the good flexibility of the second coil 5 can also be utilized.

[0034] The second coil 5 has a portion that is offset in the longitudinal direction from the non-overlapping portion 5b of the coil 5 relative to the electrode pair 6. With this configuration, the good flexibility of the second coil 5 can be utilized on the side opposite the non-overlapping portion 5b of the coil 5.

[0035] In the second modified example, the shock wave generating circuit 9 has a second electrode pair 6 (the left electrode pair 6 in Figure 5) inside the balloon 4, and one electrode of the second electrode pair 6 is connected to the other end of the second coil 5. With this configuration, the shock wave generated by the second electrode pair 6 can also be utilized.

[0036] The second coil 5 has a portion positioned between the electrode pair 6 and the second electrode pair 6 in the longitudinal direction. With this configuration, shock waves can be generated at multiple locations in the longitudinal direction by the electrode pair 6 and the second electrode pair 6, and the second coil 5 can exhibit good flexibility between the electrode pair 6 and the second electrode pair 6.

[0037] In the second modified example, the other electrode of the second electrode pair 6 is connected to the other end of the coil 5. In other words, the shock wave generating circuit 9 is composed of two sets of coils 5 and electrode pairs 6. However, the shock wave generating circuit 9 may be composed of three or more sets of coils 5 and electrode pairs 6.

[0038] While embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above, and the embodiments described above can be modified in various ways without departing from the gist of this disclosure.

[0039] For example, in the embodiment described above, the shock wave generation circuit 9 is a closed circuit, and an electromotive force is generated in the coil 5 by electromagnetic induction. However, the configuration is not limited to this, for example, the shock wave generation circuit 9 may be connected to an external power source of the medical elongated body 2. [Explanation of symbols]

[0040] 1. Medical-grade long-length system 2 Medical-grade long body 2a Long body 2b Control section 3 Starting device 3a electromagnet 3b Power supply section 4 Balloons 5 coils 5A coil (A) 5B Coil (B) 5a Overlapping section 5b Non-overlapping area 6 electrode pairs 6A electrode pair (A) 6B electrode pair (B) 6a tube electrode 6a1 Notch 6b Electrode piece 7 Non-coil section 8 Base material 9. Shock wave generation circuit 9A Shock wave generation circuit (A) 9B Shock wave generation circuit (B) 10. Tube-side conductor 10A Tube-side conductor (A) 10B Tube-side conductor (B) 11. Single-sided conductor 11A Single-sided conductor (A) 11B Single-sided conductor (B) O center axis

Claims

1. A long medical body that extends in a long length and has a central axis that extends in the longitudinal direction, It has a conductive coil and an electrode pair at the distal end. The coil extends in the longitudinal direction while spirally circling the central axis, The electrode pair is a long medical device that generates a shock wave by discharging when a voltage is applied between the electrode pair through the coil.

2. The medical elongated body according to claim 1, comprising the electrode pair and the coil, and having a closed circuit for applying the voltage between the electrode pair.

3. The medical elongated body according to claim 1, wherein the electrode pair is arranged to overlap the coil from the radially outer side.

4. The medical elongated body according to claim 1, wherein the electrode pair is arranged so as not to overlap radially with respect to the coil.

5. Having a second coil, One electrode of the electrode pair is connected to one end of the coil, The medical elongated body according to claim 1, wherein the other electrode of the electrode pair is connected to one end of the second coil.

6. Having a second pair of electrodes, The medical elongated body according to claim 5, wherein one electrode of the second electrode pair is connected to the other end of the second coil.

7. The medical elongated body according to claim 6, wherein the second coil has a portion disposed between the electrode pair and the second electrode pair in the longitudinal direction.

8. A medical elongated body according to claim 1, configured as a catheter.

9. The medical elongated body according to claim 8, having a balloon covering the electrode pair.

10. A medical elongated body according to claim 1, A medical long-body system comprising a starting device that generates an electromotive force in the coil by electromagnetic induction.

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