JP2024104068A - Medical device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medical device that can move forward and backward in a body cavity smoothly and enlarge a diameter of a site to be treated in a reliable manner.

SOLUTION: A medical device 1 includes: a core shaft 11 having a tapered part 111 whose diameter is enlarged from the tip to the base end, and a straight part 112 adjacent to the tapered part 111 whose outer diameter is constant and which extends along a longitudinal axis direction; and a spiral convex part 21 provided on the tapered part 111 or on the outer peripheral surface of the tapered part 111 and the straight part 112, including a space s in the parts adjacent along the longitudinal axis direction. A cover member 31 is provided so as to cover the outer periphery of the spiral convex part 21, and gas g is interposed between the cover member 31 and the core shaft 11.

SELECTED DRAWING: Figure 3A

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a medical device.

Dilators, for example, are known as medical devices for expanding holes in the walls of organs such as the stomach or liver, or narrowed areas in body cavities such as the bile duct or pancreatic duct.

Such medical devices have a tapered section on the core shaft, and the hole is expanded by pushing this tapered section into the hole. In order to ensure that the tapered section can be advanced through the hole while resisting resistance from the tissue, for example, a medical device has been proposed in which a helical convex section is provided on the outer periphery of the tapered section and the adjacent straight section (see, for example, Patent Document 1).

With this type of medical device, rotating the core shaft creates a screw action due to the helical convex portion, allowing the hole to be expanded while the tapered portion is reliably pushed into the hole.

Special table 2014-524807 publication

However, in conventional medical devices such as those described above, the spiral projections are always exposed on the surface. Therefore, when the medical device is delivered to the treatment site or pulled out, there is a risk that the spiral projections will interfere with smooth advancement and retreat of the medical device or that the tissue will be damaged due to the large contact resistance between the medical device and the tissue during delivery.

The present invention was made based on the above circumstances, and its purpose is to provide a medical device that can smoothly advance and retreat within a body cavity and reliably expand the diameter of the area to be treated.

Some aspects of the present disclosure include:
(1) A core shaft having a tapered portion that expands in diameter from a tip end to a base end, and a straight portion that is adjacent to the tapered portion and extends along a longitudinal direction and has a constant outer diameter;
a spiral convex portion provided on an outer circumferential surface of the tapered portion or the tapered portion and the straight portion, the spiral convex portion having a gap between adjacent portions along the longitudinal direction,
a cover member is provided so as to cover an outer periphery of the spiral convex portion, and a gas is interposed between the cover member and the core shaft;
(2) The medical device according to (1), wherein the cover member is fixed to the core shaft.
(3) A medical device as described in (2), in which both ends of the cover member in the longitudinal direction are fixed to the core shaft; and (4) a medical device as described in any one of (1) to (3), in which the cover member is formed of an elastic film-like material.

In this specification, unless otherwise specified, "longitudinal direction" refers to the longitudinal direction of the medical device. Furthermore, "distal end" refers to the distal end of any member or part, and "proximal end" refers to the proximal end of any member or part. However, "distal side" refers to the direction along the longitudinal direction of the medical device, and the direction in which the medical device advances toward the part to be treated (the part to be expanded) (distal direction). "Proximal side" refers to the direction along the longitudinal direction of the medical device, and the direction opposite to the distal side.

The present invention provides a medical device that can smoothly advance and retreat within a body cavity and reliably expand the area to be treated.

FIG. 1 is a schematic side view showing a first embodiment. 2 is a schematic cross-sectional view taken along line II-II in FIG. 1. FIG. 2 is a schematic cross-sectional view showing an enlarged portion of the first embodiment during use, illustrating the state when a medical device is delivered. FIG. 1 is a schematic cross-sectional view showing an enlarged portion of the first embodiment during use, illustrating the state when the medical device is rotated to expand the expandable portion. FIG. 4 is a schematic side view showing a second embodiment. FIG. 13 is a schematic side view showing a third embodiment. FIG. 11 is a schematic side view showing a modified example.

The following describes the first to third embodiments with reference to the drawings, but the present invention is not limited to the embodiments shown in the drawings. Also, the dimensions of each part shown in the drawings are shown to facilitate understanding of the implementation, and do not necessarily correspond to the actual dimensions.

[First embodiment]
Fig. 1 is a schematic side view showing a first embodiment. As shown in Fig. 1, the medical device 1 is generally composed of a core shaft 11, a spiral convex portion 21, a cover member 31, and a grip portion 41. The medical device 1 is a dilator.

The core shaft 11 is a member having a tapered portion and a straight portion. Specifically, the core shaft 11 can be, for example, an integrally formed hollow shaft. The tapered portion expands in diameter from the tip to the base end. The straight portion is adjacent to the tapered portion and extends along the longitudinal direction, and has a constant outer diameter.

The positional relationship (front-to-back relationship) between the tapered section and the straight section in the longitudinal direction is not particularly limited. For example, from the tip of the medical device, they may be arranged in the order of tapered section and straight section, or in the order of straight section, tapered section and straight section.

The medical device 1 of this embodiment is exemplified by a core shaft 11 in which a tapered portion 111 and a straight portion 112 are arranged in this order. The tapered portion 111 expands in diameter from the tip to the base end. The straight portion 112 extends from the base end of the tapered portion 111 toward the base end side, and has a constant outer diameter. The outer diameter of the straight portion 112 is the same as the outer diameter of the base end of the tapered portion 111, and is formed so that the base end of the tapered portion 111 and the tip of the straight portion 112 are continuous.

The core shaft 11 may have a hollow inner cavity 11h. The inner cavity 11h may be, for example, a continuous space connecting the tip and base ends of the core shaft 11. For example, a guide wire (not shown) or the like may be inserted into the inner cavity 11h.

The helical protrusion 21 is a portion provided on the outer peripheral surface of the tapered portion or the tapered portion and the straight portion. The helical protrusion 21 has a gap s between adjacent portions along the long axis direction. Specifically, the helical protrusion 21 can be, for example, a single or multiple protrusion that protrudes radially outward from the outer peripheral surface of the tapered portion or the straight portion and is continuous or discontinuous in the long axis direction. In this embodiment, the helical protrusion 21 and the core shaft 11 are integrally formed, and the helical protrusion 21 is provided on the tapered portion 111 and the straight portion 112 of the core shaft 11.

The material that constitutes the core shaft 11 and the helical protrusion 21 is preferably antithrombotic, flexible, and biocompatible, since it is inserted into a body cavity. Examples of such materials include resin materials such as polyamide resin, polyolefin resin, polyester resin, polyurethane resin, silicone resin, and fluororesin; and metal materials such as stainless steel and superelastic alloys (nickel-titanium alloys).

The cover member 31 is a member provided to cover the outer circumference of the spiral protrusion 21. Specifically, the cover member 31 can be configured, for example, as a tube-shaped member having a space inside large enough to accommodate the outermost circumference of the spiral protrusion 21.

It is preferable that the material forming the cover member 31 is elastic (easily dented), antithrombotic, and biocompatible. Examples of such materials include polyurethane resin, polyester resin, and fluororesin.

The cover member 31 may also be formed from a film-like material having elasticity. The elasticity of the cover member 31 can further reduce irritation to the tissue, and when the area to be treated is enlarged, the spiral shape of the outer peripheral surface 31b of the cover member 31 becomes more apparent along the shape of the spiral protrusion 21, and the screw action can more reliably enlarge the area to be treated.

The cover member 31 only needs to be provided so as to cover the outer periphery of the helical protrusion 21, and does not necessarily need to be fixed to the core shaft 11. However, the cover member 31 may be fixed to the core shaft 11 so that the cover member 31 can stably cover the outer periphery of the helical protrusion 21. This makes it possible to prevent the cover member 31 from shifting in the longitudinal direction relative to the core shaft 11, for example, when delivering the medical device 1.

The medical device 1 of the present disclosure is configured such that a gas g is interposed between the cover member 31 and the core shaft 11. As shown in FIG. 2, for example, the tip (end on the outer periphery) of the spiral convex portion 21 in the radial direction abuts against the inner circumferential surface 31a of the cover member 31, and the space surrounded by the core shaft 11, the spiral convex portion 21, and the cover member 31 (the portion of the gap s between the adjacent spiral convex portions 21 along the longitudinal direction) is filled with the gas g. Note that, as long as the gas g is interposed between the cover member 31 and the core shaft 11, the tip of the spiral convex portion 21 does not necessarily have to abut against the inner circumferential surface 31a of the cover member 31.

Both ends of the cover member 31 in the longitudinal direction may be fixed to the core shaft 11 so that the gas g does not leak to the outside. This fixing may be in a form in which it is fixed to the core shaft 11 only by contraction force, or may be made by using an adhesive, or may be in another form. The part of the core shaft 11 to which the cover member 31 is fixed is not particularly limited. In this embodiment, the tip end of the cover member 31 and the outer periphery of the tapered portion 111 of the core shaft 11 located on the tip side of the helical convex portion 21 are fixed by the fixing portion f11, and the base end of the cover member 31 and the outer periphery of the straight portion 112 of the core shaft 11 located on the base side of the helical convex portion 21 are fixed by the fixing portion f12.

In this way, by fixing both ends of the cover member 31 to the core shaft 11, the elasticity of the gas g when compressed can reduce the irritation to the tissue.

The gas g mentioned above is not particularly limited as long as it does not adversely affect the tissue. Examples of the gas g include inert gases such as nitrogen and argon, and air.

The pressure of the gas g is not particularly limited as long as it does not impair the effects of the present invention. For example, the pressure of the gas g may be a pressure that makes the outer peripheral surface 31b of the cover member 31 flat (flat enough that the shape of the helical convex portion 21 does not appear on the outer peripheral surface 31b of the cover member 31) when the medical device 1 is delivered.

The grip portion 41 is the part where the technician pushes the medical device 1 into the body and rotates it. The tip of the grip portion 41 is connected to the base end of the core shaft 11, and has an inner cavity 41h that communicates with the inner cavity 11h of the core shaft 11. The shape of the grip portion 41 can be formed, for example, to make it easy for the technician to operate the medical device 1.

The above-mentioned inner cavity 11h and inner cavity 41h form a lumen L. A guide wire, for example, is inserted into the lumen L.

Next, we will explain how to use the medical device 1. Here, we will explain an example of a procedure in which an introduction needle (not shown) is used to make a hole in the area to be treated (for example, the wall of an organ such as the stomach or liver, hereinafter also referred to as the "area to be expanded"), and then the hole is expanded using the medical device 1.

First, the introduction needle is used to puncture the expanded portion to create a hole. Next, a guidewire (not shown) is inserted into the lumen of the introduction needle, and the introduction needle is then removed.

Next, the medical device 1 is inserted into the body. Specifically, the base end of the guide wire is inserted into the lumen L of the medical device 1. Next, while operating the gripping portion 41, the tip of the medical device 1 is delivered linearly along the guide wire to just before the enlarged portion. When the medical device 1 is delivered, the core shaft 11 may or may not rotate. If it rotates, the direction of rotation may be any. At this time, the core shaft 11 has not yet been inserted into the hole, and the cover member 31 does not receive pressure from the inner wall of the hole toward the spiral convex portion 21. Therefore, as shown in FIG. 3A, the cover member 31 is not pressed against the spiral convex portion 21 by the pressure of the gas g interposed between the cover member 31 and the core shaft 11. As a result, the outer peripheral surface 31b of the cover portion 31 material is maintained in an approximately flat state, and the medical device 1 is delivered linearly while suppressing the resistance from the tissue.

Next, the hole is expanded. Specifically, the core shaft 11 is inserted from its tip into the hole of the expanded diameter portion. Next, the core shaft 11 is rotated while operating the gripping portion 41 to push the medical device 1 forward. At this time, the cover member 31 receives pressure from the inner wall of the hole toward the spiral protrusion 21. Therefore, as shown in FIG. 3B, the gas g interposed between the cover member 31 and the core shaft 11 is compressed, and the inner surface 31a of the cover member 31 is pressed against the spiral protrusion 21. As a result, the spiral shape of the spiral protrusion 21 is manifested on the outer surface 31b of the cover member 31, and the screw action of this spiral shape causes the tapered portion 111 to advance, and the tapered shape expands the hole.

Next, after the hole is expanded, the medical device 1 is removed from the body. Specifically, while operating the gripping portion 41, the core shaft 11 is pulled out of the body in a straight line along the guide wire. At this time, since the hole has already been expanded, the cover member 31 does not receive pressure from the inner wall of the tissue toward the spiral convex portion 21. Therefore, as shown in FIG. 3A, the pressure of the gas g interposed between the cover member 31 and the core shaft 11 returns the outer peripheral surface 31b of the cover member 31 to an approximately flat state, and the medical device 1 is removed without receiving a large resistance from the tissue.

As described above, because the medical device 1 has the above-mentioned configuration, when the medical device 1 is delivered to the site to be treated or pulled out, the resistance from the contacting tissue can be reduced, allowing the medical device 1 to move smoothly forward and backward within the body cavity. Furthermore, when the site to be treated is to be enlarged, the cover member 31 is pressed against the spiral convex portion 21, and the screw action associated with the spiral shape manifested on the outer circumferential surface 31b of the cover member 31 reliably enlarges the site to be treated.

Second Embodiment
4 is a schematic side view showing the second embodiment. As shown in FIG. 4, the medical device 2 is generally composed of a core shaft 12, a spiral convex portion 22, a cover member 32, and a grip portion 41. The medical device 2 differs from the first embodiment in the configurations of the core shaft 12, the spiral convex portion 22, and the cover member 32. The configuration of the grip portion 41 is the same as that of the first embodiment, so the same parts are given the same reference numerals and detailed description thereof is omitted. In addition, the configuration other than the configurations of the core shaft 12, the spiral convex portion 22, and the cover member 32 shown below, and the usage mode of the medical device 2 are the same as those of the first embodiment.

The core shaft 12 is a member having a tapered portion and a straight portion. The tapered portion expands in diameter from the tip to the base end. The straight portion is adjacent to the tapered portion and extends along the longitudinal axis, and has a constant outer diameter.

The medical device 2 of this embodiment is illustrated with a core shaft 12 arranged in the following order from the tip: straight section 121, tapered section 122, and straight section 123.

The straight portion 121 extends from the tip of the tapered portion 122 toward the tip side, and has a constant outer diameter. The outer diameter of the straight portion 121 is the same as the outer diameter of the tip of the tapered portion 122, and is formed so that the base end of the straight portion 121 and the tip of the tapered portion 122 are continuous. The tapered portion 121 expands in diameter from the tip to the base end. The straight portion 123 extends from the base end of the tapered portion 122 toward the base end side, and has a constant outer diameter. The outer diameter of the straight portion 123 is the same as the outer diameter of the base end of the tapered portion 122, and is formed so that the base end of the tapered portion 122 and the tip of the straight portion 123 are continuous.

The helical protrusion 22 is a portion provided on the outer peripheral surface of the tapered portion or the tapered portion and the straight portion. The helical protrusion has a gap s between adjacent portions along the long axis direction. In this embodiment, the helical protrusion 22 is provided on the outer peripheral surfaces of the straight portion 121, the tapered portion 122, and the straight portion 123.

The cover member 32 is a member provided to cover the outer periphery of the helical protrusion. In this embodiment, it is arranged to cover the outer periphery of the helical protrusion 22 provided on the outer periphery of the straight portion 121, the tapered portion 122, and the straight portion 123. In addition, both ends of the cover member 32 in the longitudinal direction are fixed in an airtight manner to the outer periphery of the core shaft 12 at the fixing portions f21 and f22, respectively, and the gas g is sealed between the cover member 32 and the core shaft 12.

As described above, the medical device 2 has the above-mentioned configuration, so it can smoothly advance and retreat within the body cavity and can reliably expand the diameter of the area to be treated. In addition, in the medical device 2 of this embodiment, the core shaft 12 has a straight portion 121, so that the straight portion 121 can be inserted into the hole before expanding the hole with the tapered portion 122, and the expansion of the hole with the tapered portion 122 can begin more smoothly.

[Third embodiment]
5 is a schematic side view showing the third embodiment. As shown in FIG. 5, the medical device 3 is generally composed of a core shaft 13, a spiral convex portion 23, a cover member 31, and a grip portion 41. The medical device 3 differs from the first embodiment in the configurations of the core shaft 13 and the spiral convex portion 23. Note that the configurations of the cover member 31 and the grip portion 41 are the same as those of the first embodiment, so the same reference numerals are given to the same parts, and detailed descriptions thereof are omitted. In addition, the configurations other than the configurations of the core shaft 13 and the spiral convex portion 23 shown below, and the usage mode of the medical device 3 are the same as those of the first embodiment.

The core shaft 13 is a member having a tapered portion and a straight portion. The tapered portion expands in diameter from the tip to the base end. The straight portion is adjacent to the tapered portion and extends along the longitudinal axis, and has a constant outer diameter.

The core shaft 13 in this embodiment has a tapered portion 131 and a straight portion 132. The core shaft 13 is composed of an integrally formed hollow shaft.

The helical protrusion 23 is a portion provided on the outer peripheral surface of the tapered portion or the tapered portion and the straight portion. The helical protrusion 23 has a gap s between adjacent portions along the longitudinal direction.

In this embodiment, the helical protrusion 23 is composed of a coil body 23C in which a wire 23w is wound around the outer circumferential surface of the core shaft 13. Specifically, the coil body 23C may be formed, for example, by using one or more wires 23w and winding them in a helical shape so that adjacent wires 23w are spaced apart.

Examples of the material of the wire 23w that constitutes the coil body 23C include materials similar to those exemplified as the material that constitutes the helical protrusion 21 in the first embodiment.

Methods for joining the coil body 23C and the core shaft 13 include, for example, brazing the coil body 23C and the core shaft 13 with a brazing material, gluing with an adhesive, welding, etc. Examples of the brazing material include metal brazing materials such as Sn-Pb alloy, Pb-Ag alloy, Sn-Ag alloy, and Au-Sn alloy. Examples of the adhesive include epoxy adhesives and cyanoacrylate adhesives.

In this embodiment, both ends of the cover member 31 in the longitudinal direction are fixed to the outer circumferential surface of the core shaft 13 at fixing portions f31 and f32, respectively.

As described above, the medical device 3 has the above-mentioned configuration, and therefore can smoothly advance and retreat within the body cavity, and can reliably expand the diameter of the area to be treated. Furthermore, in the medical device 3 of this embodiment, the helical protrusion 23 is formed from the coil body 23C. This can increase the flexibility of the helical protrusion 23, and therefore the flexibility of the medical device 3, and can also improve torque transmission. Furthermore, since the helical protrusion 23 is made from the coil body 23C, the helical protrusion 23 can be easily formed using the wire 23w.

The present disclosure is not limited to the configurations of the above-described embodiments, but is intended to include all modifications within the scope and meaning equivalent to the claims, as set forth in the claims. Some of the configurations of the above-described embodiments may be deleted or replaced with other configurations, and other configurations may be added to the configurations of the above-described embodiments.

For example, in the above-described embodiment, medical devices 1, 2, and 3 in which cover members 31 and 32 are fixed to core shafts 11, 12, and 13 have been described. However, as long as the cover members can stably cover the outer periphery of the helical convex portion, the cover members do not need to be fixed to the core shaft.

In the above-described embodiment, medical devices 1, 2, and 3 are described in which both ends of the cover members 31 and 32 in the longitudinal direction are fixed to the core shafts 11, 12, and 13, respectively. However, the cover members may be fixed to any part of the core shaft and/or the helical protrusion as long as the effect of the present invention is not impaired.

In the above-mentioned embodiment, the medical devices 1, 2, and 3 in which the core shafts 11, 12, and 13 are integrally formed have been described. However, as shown in FIG. 6, the core shaft 14 may be formed of a coil body 14C in which the wire 14w is wound in a spiral shape around the long axis of the core shaft 14. In such a case, for example, it is desirable to use one or more wires 14w and cover the coil body of the core shaft with a resin layer so that gas g does not leak between adjacent wires 14w. The tapered portion 141 and the straight portion 142 can be formed by adjusting the shape of the outer circumferential surface of the coil body 14C. In addition, the region surrounded by the common inscribing line (shown by a dashed line in FIG. 6) of the coil body 14C becomes the inner cavity 14h of the core shaft 14. When the core shaft 14 is formed of the coil body 14C, the helical convex portion can also be formed of the coil body, as in the third embodiment.

1, 2, 3 Medical device 11, 12, 13, 14 Core shaft 111, 122, 131, 141 Tapered portion 112, 121, 123, 132, 142 Straight portion 21, 22, 23, 24 Spiral convex portion s Gap 31, 32 Cover member g Gas

Claims (4)

a core shaft having a tapered portion that expands in diameter from a tip end to a base end, and a straight portion that is adjacent to the tapered portion and extends along a longitudinal direction and has a constant outer diameter;
a spiral convex portion provided on an outer circumferential surface of the tapered portion or the tapered portion and the straight portion, the spiral convex portion having a gap between adjacent portions along the longitudinal direction,
A cover member is provided so as to cover an outer periphery of the spiral convex portion,
A medical device, comprising: a gas interposed between the cover member and the core shaft. The medical device according to claim 1, wherein the cover member is fixed to the core shaft. The medical device according to claim 2, wherein both ends of the cover member in the longitudinal direction are fixed to the core shaft. The medical device according to any one of claims 1 to 3, wherein the cover member is formed of a film-like material having elasticity.

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