CATHETER

A catheter including a main lumen, a plurality of sub lumens arranged around the main lumen and spirally formed around the main lumen, a plurality of operating wires inserted into each of the plurality of sub lumens, a distal end flexible portion arranged on a distal end side of the catheter and curvable by the plurality of operating wires, and a holding portion arranged at a distal end of the distal end flexible portion and holding each of the plurality of operating wires, in which each of the plurality of sub lumens is wound by a half turn or more in the distal end flexible portion.

TECHNICAL FIELD

The disclosed embodiments relate to a catheter.

BACKGROUND

A catheter can be used by inserting the catheter into a living lumen such as a vascular system, a lymph gland system, a biliary system, a urinary tract system, a respiratory system, a digestive system, a secretory gland, and a reproductive organ. For example, the catheter can be curved in a direction intersecting a longitudinal direction of the catheter by using an operation thread such as an operating wire to position a distal end side of the catheter in the vicinity of a living tissue (for example, see Patent Literatures 1 to 3).

CITATION LIST

Patent Literature

Patent Literature 1: JP 2015-188569 A

Patent Literature 2: JP 2014-111139 A

Patent Literature 3: JP 2015-159969 A

SUMMARY

TECHNICAL PROBLEM

The techniques described in Patent Literatures 1 and 2 have a problem with operability of the operating wire or the like in a state where a distal end portion is curved. The technique described in Patent Literature3has a problem in that although the catheter includes a structure including an operation-thread sub lumen capable of moving in a circumferential direction, which is a structure that can respond to a change in natural length due to differences in vascular routes, if the distal end portion is curved greatly, it is not easy to perform a stable operation in the circumferential direction of the operation-thread sub lumen.

The disclosed embodiments have been made to address the above-mentioned problems, and an object thereof is to improve operability in a curvable catheter.

SOLUTION TO PROBLEM

The disclosed embodiments been contrived to solve at least some of the above-described problems, and can be realized according to the following aspects.

(1) According to one aspect of the disclosed embodiments, a catheter is provided. The catheter includes a main lumen, a plurality of sub lumens arranged around the main lumen and spirally formed around the main lumen, a plurality of operating wires inserted into each of the plurality of sub lumens, a distal end flexible portion arranged on a distal end side of the catheter and curvable by the plurality of operating wires, and a holding portion arranged at a distal end of the distal end flexible portion and holding each of the plurality of operating wires, in which each of the plurality of sub lumens is wound by a half turn or more in the distal end flexible portion.

According to such a configuration, each of the plurality of sub lumens is wound by a half turn or more in the distal end flexible portion. Therefore, as a result of the operating wires being operated, if the distal end flexible portion of the catheter is curved, tension is exerted on a part corresponding to the outside of the curved portion in the sub lumen, and tension is loosened in a part corresponding to the inside of the curved portion. As a result, the tensions exerted on the sub lumen are canceled out, and thus, a drag force when the operating wires are operated is reduced, and it is possible to improve the operability. The plurality of sub lumens are each formed in a spiral shape, and thus, if any operating wire, of the plurality of operating wires, is pulled, the drag force exerted on each operating wire is reduced, and it is possible to improve the operability.

(2) In the catheter of the above aspect, the plurality of sub lumens may be each arranged at substantially equal intervals in a circumferential direction of the main lumen. With such a configuration, the plurality of sub lumens are arranged at equal intervals in the circumferential direction of the main lumen, and thus, it is possible to appropriately operate the distal end flexible portion in a curving direction.

(3) The catheter of the above aspect may be provided with a hollow tubular main tube configuring the main lumen, a plurality of hollow tubular sub tubes configuring each of the plurality of sub lumens; and a hollow tubular outer tube containing the main tube and the sub tubes. With such a configuration, it is possible to provide a catheter that can be easily manufactured.

(4) In the catheter of the above aspect, the plurality of sub lumens may include a first sub lumen and a second sub lumen, and the plurality of operating wires may include a first operating wire inserted into the first sub lumen and a second operating wire inserted into the second sub lumen. With such a configuration, it is possible to provide a catheter that can be easily operated and manufactured.

The disclosed embodiments can be realized in various aspects, and for example, can be realized in a mode such as a catheter, a main body portion for the catheter, and a method of manufacturing the catheter and the main body portion.

DETAILED DESCRIPTION OF EMBODIMENTS <First Aspect>

FIG. 1is an explanatory diagram illustrating a configuration of a catheter1of the disclosed embodiments. The catheter1is inserted into a living lumen such as a vascular system, a lymph gland system, a biliary system, a urinary tract system, a respiratory system, a digestive system, a secretory gland, and a reproductive organ to be used to diagnose or treat the inside of the living lumen. The catheter1includes a tube-shaped (tubular) main body portion100and a connector200connected to a proximal end side of the main body portion100. A distal end flexible portion50configured to be curvable is provided on a distal end side of the catheter1.

InFIG. 1, an axis passing through a center of the catheter1is represented by an axial line O (dash-dot-dash line). In an example ofFIG. 1, the axial line O coincides with an axis passing through a center of each of the main body portion100and the connector200. However, it may not be required that the axial line O coincides with each central axial line of the main body portion100and the connector200.FIG. 1illustrates an X-axis, a Y-axis, and a Z-axis orthogonal to one another. The X-axis corresponds to a longitudinal direction (length direction) of the catheter1, the Y-axis corresponds to a width direction of the catheter1, and the Z-axis corresponds to a height direction of the catheter1. The left side (- X-axial direction) inFIG. 1is referred to as “distal end side” of the catheter1and each constituent component, and the right side inFIG. 1(+X-axial direction) is referred to as “proximal end side” of the catheter1and each constituent component. As for the catheter1and each constituent component, an end located on the distal end side is referred to as a “distal end”, and the distal end and the vicinity thereof are referred to as a “distal end portion”. Further, an end located on the proximal end side is referred to as a “proximal end”, and the proximal end and the vicinity thereof are referred to as a “proximal end portion”. The distal end side is inserted inside a living body, and the proximal end side is operated by an operator such as a doctor. The same is true in the drawings fromFIG. 1onward.

FIG. 2is an explanatory diagram illustrating the catheter1with the distal end flexible portion50being curved. As will be described in detail later, in the catheter1of the present embodiment, the distal end flexible portion50can be curved as illustrated inFIG. 2by operating an operating wire (described later).

FIG. 3is an explanatory diagram illustrating a longitudinal sectional configuration of a part of the distal end flexible portion50of the catheter1. As illustrated inFIG. 3, the main body portion100includes an outer tube60, a main tube10(an inner tube), a first sub tube21, a second sub tube22, a first operating wire31, a second operating wire32, and a holding portion40. The outer tube60is an elongated member extending along the longitudinal direction (axial line O) of the catheter1and is a hollow, substantially cylindrical member. An outer diameter and a length of the outer tube60can be freely determined.

Similarly to the outer tube60, the main tube10is an elongated member extending along the longitudinal direction (axial line O) of the catheter1and is a hollow, substantially cylindrical member. That is, the main tube10configures an inner cavity (a main lumen100extending across a distal end of the main tube10and a proximal end thereof. As illustrated InFIG. 3, the main tube10is arranged in the outer tube60. An outer diameter of the main tube10is smaller than an inner diameter of the outer tube60. A length of the main tube10is substantially the same as a length of the outer tube60.

The first sub tube21is a hollow, elongated member having a substantially cylindrical shape. That is, the first sub tube21configures an inner cavity (a first sub lumen210extending across a distal end of the first sub tube21and a proximal end thereof. Similarly to the first sub tube21, the second sub tube22is a hollow, elongated member having a substantially cylindrical shape. That is, the second sub tube22configures an inner cavity (a second sub lumen22L) extending across a distal end of the second sub tube22and a proximal end thereof. The first sub tube21and the second sub tube22are arranged inside the outer tube60and outside the main tube10.

FIG. 4is an explanatory diagram of a configuration of the distal end flexible portion50. As illustrated inFIG. 4, the first sub tube21and the second sub tube22are arranged around the main tube10and are spirally formed around the main tube10. In other words, the first sub lumen21L and the second sub lumen22L are spirally formed around the main lumen10L.

In the present embodiment, a spiral pitch of the first sub tube21(a length L1illustrated inFIG. 4) and a spiral pitch of the second sub tube22(a length L2illustrated inFIG. 4) are substantially the same, and can be appropriately set within a range of 15 mm or more and 150 mm or less, for example.

The first sub tube21and the second sub tube22are each wound by a half turn or more (for example, four times) in the distal end flexible portion50. In other words, the first sub lumen21L and the second sub lumen22L are each wound by a half turn or more in the distal end flexible portion50.

FIG. 5is a cross-sectional view taken along A-A inFIG. 4,FIG. 6is a cross-sectional view taken along B-B,FIG. 7is a cross-sectional view taken along C-C, andFIG. 8is a cross-sectional view taken along D-D. As illustrated inFIGS. 5 to 8, the first sub tube21and the second sub tube22are each arranged at substantially equal intervals in a circumferential direction of the main tube10. In other words, the first sub lumen21L and the second sub lumen22L are each arranged at substantially equal intervals in the circumferential direction of the main lumen10L. Here, the “substantially equal intervals” include a tolerance of about ±20° , for example. The first sub tube21and the second sub tube22are each spirally wound around the main tube10, with the main tube10as a center, while maintaining a relative positional relationship with each other.

As illustrated inFIGS. 3 and 5 to 8, the first operating wire31is a solid and elongated member. The first operating wire31is arranged in the first sub tube21, that is, in the first sub lumen21L, and is spirally wound, similarly to the first sub lumen21L of the first sub tube21. As illustrated inFIGS. 3 and 5, the distal end portion of the first operating wire31is integrally held by the holding portion40with the outer tube60, the main tube10, and the first sub tube21. The proximal end portion of the first operating wire31is wound around and fixed by a first winding portion92A described later (FIG. 1).

As illustrated inFIGS. 3 and 5 to 8, the second operating wire32is a solid and elongated member, similarly to the first operating wire31. The second operating wire32is arranged in the second sub tube22, that is, in the second sub lumen22L, and is spirally wound, similarly to the second sub lumen22L of the second sub tube22. As illustrated inFIGS. 3 and 5, the distal end portion of the second operating wire32is integrally held by the holding portion40with the outer tube60, the main tube10, and the second sub tube22. The proximal end portion of the second operating wire32is wound around and fixed by a second winding portion92B described later (FIG. 1). In the following description, if there is no need of distinguishing the first operating wire31and the second operating wire32, these are simply referred to as “operating wire”.

The holding portion40is arranged at the distal end portion of the outer tube60, and is a member that integrally holds a distal end side of the main tube10, a distal end side of the first operating wire31, a distal end side of the second operating wire32, a distal end side of the first sub tube21, and a distal end side of the second sub tube22. As illustrated inFIGS. 3 and 5, the holding portion40is provided inside the outer tube60and over the entire outside of the main tube10, but is not provided inside the main tube10. Thus, it is possible to use the main lumen10L of the main tube10as a guide wire lumen for inserting a guide wire into the catheter1or as a lumen for a chemical liquid for supplying a chemical liquid to a living tissue.

As illustrated inFIG. 1, the connector200is a member arranged at a proximal end portion10p of the main body portion100and gripped by an operator. The connector200includes a connector main body portion91, a winding portion92, and a blade portion93. The connector main body portion91has a hollow shape including an opening at each of a distal end portion90d and a proximal end portion90p and having formed therein an inner cavity communicating with each opening. A distal end side of the connector main body portion91is joined with a part of the proximal end side of the main body portion100being inserted therein. For joining, any adhesive such as an epoxy-based adhesive can be utilized.

The winding portion92includes the first winding portion92A and the second winding portion92B. The first winding portion92A and the second winding portion92B each include a tubular or rod-shaped wire wound portion and a grip portion provided on the outside of the wire wound portion. The wire wound portion of the first winding portion92A is wound and fixed with the proximal end portion of the first operating wire31. When the grip portion of the first winding portion92A is rotated clockwise, the proximal end portion of the first operating wire31is wound around the wire wound portion, and as a result, it is possible to perform an operation of pulling the proximal end side of the first operating wire31. When the grip portion of the first winding portion92A is rotated counterclockwise, the proximal end portion of the first operating wire31is fed out from the wire wound portion, and as a result, it is possible to perform an operation of loosening the first operating wire31. Similarly, the wire wound portion of the second winding portion92B is wound and fixed with the proximal end portion of the second operating wire32. When the grip portion of the second winding portion92B is rotated clockwise, it is possible to perform an operation of pulling the proximal end side of the second operating wire32. When the grip portion of the second winding portion92B is rotated counterclockwise, it is possible to perform an operation of loosening the second operating wire32.

The blade portion93is a blade-shaped member having two blades provided on the proximal end side of the connector main body portion91. The blade portion93is used by the operator to grip the catheter1. The blade portion93may have any shape and may be omitted. The blade portion93may be joined to the connector main body portion91, or may be integrally formed with the connector main body portion91.

The outer tube60, the main tube10, the first sub tube21, and the second sub tube22preferably have antithrombotic, flexible, and biocompatible properties, and may be formed of a resin material or a metal material. Examples of the resin material may include a polyamide resin, a polyolefin resin, a polyester resin, a polyurethane resin, a silicone resin, and a fluororesin. Examples of the metal material may include stainless steel such as SUS304, a nickel-titanium alloy, and a cobalt-chromium alloy. In addition, if gold, platinum, and tungsten, which are radiopaque materials, or an alloy containing these elements are adopted, it is possible to improve visibility under X-ray fluoroscopy, which may be preferable.

The first operating wire31and the second operating wire32may be formed of, for example, a metal material such as stainless steel including SUS304, a nickel titanium alloy, a cobalt chrome alloy, and a tungsten alloy. The holding portion40is preferably flexible and may be formed of, for example, a resin material such as polyurethane and polyurethane elastomer. The connector200may be formed of, for example, a resin material such as polyamide, polypropylene, polycarbonate, polyacetal, and polyether sulfone. It is noted that each of the above-mentioned materials is merely an example, and each member may be formed by using a known material other than the materials mentioned above.

In the main body portion100of the catheter1, the distal end flexible portion50is more flexible than the other parts of the main body portion100. Various methods may be used to modify the flexibility of the main body portion100. For example, thicknesses of the outer tube60, the main tube10, the first sub tube21, and the second sub tube22may be reduced in the distal end flexible portion50. Parts of the outer tube60, the main tube10, the first sub tube21, and the second sub tube22, corresponding to the distal end flexible portion50, may be formed of a material having a lower rigidity (a material having a higher flexibility) than the other parts. The distal end flexible portion50may be provided at a site of a portion between the distal end of the main body portion100and a position separated by a predetermined distance. For example, the predetermined distance may be 100 mm, or a part of the predetermined distance, for example, the distal end flexible portion50may be formed in a range of 20 to 50 mm from the distal end.

Prior to the description of an effect of the catheter1of the disclosed embodiments, a conventional catheter will be described.FIG. 9is an explanatory diagram for describing a configuration of a known catheter1P.FIG. 9is a longitudinal cross section corresponding toFIG. 3. In the catheter1P, a first sub tube21P and a second sub tube22P are formed linearly along the axial line O in a distal end flexible portion50P. Therefore, in the catheter1P, a first operating wire31P and a second operating wire32P are also formed linearly.

FIG. 10is an explanatory diagram illustrating a case where the distal end flexible portion50P of the catheter1P is curved. InFIG. 10, to distinguish the main tube10, the first sub tube21P, and the second sub tube22P, a different hatching is added. When the first operating wire31P is pulled to curve the distal end flexible portion50P, tension is generated in the second sub tube22P and the second operating wire32P, and thus, a drag force against the tension is generated (arrow inFIG. 10) in the second sub tube22P and the second operation wire32P. Thus, due to the drag force generated in the second sub tube22P and the second operating wire32P when the first operating wire31P is pulled to further curve the distal end flexible portion50P, it is difficult to pull the first operating wire31P. That is, it is difficult to curve the distal end flexible portion50P.

FIG. 11is an explanatory diagram of an effect of the catheter1of the present embodiment.FIG. 11illustrates the main tube10and the first sub tube21in a state where the distal end flexible portion50of the catheter1is curved. For example, if the distal end flexible portion50is curved by pulling the first operating wire31arranged in the first sub lumen21L inside the first sub tube21, the first sub tube21is deformed as the main tube10is curved. InFIG. 11, beyond a central axial line O1of the main tube10, outside the curving of the main tube10(inFIG. 11, an example of such a range is allotted with reference symbol R1), the main tube10is stretched and tension is exerted on the first sub tube21. On the other hand, beyond the central axial line O1of the main tube10, inside the curving of the main tube10(inFIG. 11, an example of such a range is allotted with reference symbol R2), the main tube10contracts and the tension on the first sub tube21is loosened. That is, if the first sub tube21is wound by a half turn to include the part where the tension is generated and the part where the tension is loosened, the tensions are canceled out in such parts. In the catheter1of the present embodiment, the first sub tube21is spirally wound by a half turn or more in the distal end flexible portion50, and thus, the tension generated in the first sub tube21is canceled out. As a result, a force generated in the first operating wire31arranged in the first sub lumen21L of the first sub tube21is suppressed. Therefore, it is possible to improve the operability when the operating wire is operated in a state where the distal end flexible portion50of the catheter1is curved.

According to the catheter1of the present embodiment, the second sub tube22is spirally formed, similarly to the first sub tube21. Therefore, it is possible to obtain a similar effect when the second operating wire32arranged in the second sub lumen22L of the second sub tube22is pulled to curve the distal end flexible portion50.

In the catheter1of the present embodiment, the first sub tube21and the second sub tube22are arranged substantially evenly in the circumferential direction of the main tube10. Therefore, it is possible to easily curve the distal end flexible portion50in a direction desired by the operator.

In the catheter1of the present embodiment, the main lumen10L is configured by the main tube10, the first sub lumen21L is configured by the first sub tube21, and the second sub lumen22L is configured by the second sub tube22. Therefore, it is possible to easily manufacture the catheter1spirally formed with the first sub lumen21L and the second sub lumen22L.

FIG. 12is an explanatory diagram of a configuration of a distal end flexible portion50A of a catheter1A of the disclosed embodiments. In addition to the configuration of the catheter1, the catheter1A further includes a third sub tube23, a third operating wire33arranged in the third sub tube23, a fourth sub tube24, and a fourth operating wire34arranged in the fourth sub tube24. In the following description, if there is no need for distinguishing the first to fourth sub tubes, these are also simply referred to as “sub tube”, and if there is no need for distinguishing the first to fourth operating wires, these are also simply referred to as “operating wire”.

As illustrated inFIG. 12, similarly to the first sub tube21and the second sub tube22, the third sub tube23and the fourth sub tube24are hollow, elongated members having a substantially cylindrical shape, arranged around the main tube10, and spirally formed around the main tube10.

FIG. 13illustrates a cross section taken along B-B inFIG. 12,FIG. 14illustrates a cross section taken along C-C, andFIG. 15illustrates a cross section taken along D-D. A cross-sectional position inFIG. 12coincides with a cross-sectional position inFIG. 4. As illustrated, the third sub tube23configures a third sub lumen23L, and the third operating wire33is arranged in the third sub lumen23L. Similarly, the fourth sub tube24configures a fourth sub lumen24L, and the fourth operating wire34is arranged in the fourth sub lumen24L.

The first sub tube21, the second sub tube22, the third sub tube23, and the fourth sub tube24are each arranged at substantially equal intervals in the circumferential direction of the main tube10. In other words, the first sub lumen21L, the second sub lumen22L, the third sub lumen23L, and the fourth sub lumen24L are each arranged at substantially equal intervals in the circumferential direction of the main lumen10L. The first sub tube21, the second sub tube22, the third sub tube23, and the fourth sub tube24are each spirally wound around the main tube10, with the main tube10as a center, while maintaining relative positional relationships with one another.

The first sub tube21, the second sub tube22, the third sub tube23, and the fourth sub tube24are each wound by a half turn or more (for example, four times) in the distal end flexible portion50. In other words, the first sub lumen21L, the second sub lumen22L, the third sub lumen23L, and the fourth sub lumen24L are each wound by a half turn or more in the distal end flexible portion50.

Even in such a configuration, each of the sub tubes is spirally wound by a half turn or more, and thus, the tensions generated in the sub tubes are canceled out, and the force generated in the operating wire can be suppressed. The four operating wires are provided, and thus, it is possible to more accurately operate the distal end flexible portion50A in the curving direction, than the catheter1.

The disclosed embodiments are not limited to the above-described embodiments, and may be implemented in various modes without departing from the spirit of the disclosed embodiments. The following modifications can be applied, for example.

- The number of sub lumens is not limited to the number in the above-described embodiments. For example, three or five or more sub lumens may be provided.

- In the above-described embodiments, an example in which the sub lumens are arranged at substantially equal intervals in the circumferential direction of the main lumen is described, but it is not required that the sub lumens are arranged at substantially equal intervals.

- In the above-described embodiments, an example of a catheter obtained by using a hollow tube having a substantially circular tubular shape to form the inner cavity (lumen) is described, but the catheter may be formed by using a multi-lumen tube including the main lumen and the sub lumen in the above-described embodiments.

- In the above-described embodiments, a blade layer formed by knitting wires may be further provided. If the blade layer is provided, the flexibility of the main body portion100may be changed depending on the presence or absence of the blade layer and the sparseness or density of the blade layer, for example. Specifically, in the main body portion100, the distal end flexible portion50may not include the blade layer, and another part may include the blade layer. In the main body portion100, the distal end flexible portion50may have a lower density of the blade layer than other parts.

- It may suffice that the sub lumen is spirally formed by a half turn or more in at least the distal end flexible portion50. For example, in a part other than the distal end flexible portion50in the main body portion100, the sub lumen may be formed linearly, and may be formed spirally with a spiral pitch larger than that of the distal end flexible portion50. In a part other than the distal end flexible portion50of the main body portion100, the sub lumen may be formed spirally with the same pitch as the spiral pitch in the distal end flexible portion50.

Although the aspects have been described based on the embodiments and the modifications, the embodiments of the above-described aspects are for facilitating understanding of the aspects, and do not limit the aspects. The aspects can be modified and improved without departing from the spirit of the aspects and the scope of the claims, and equivalent aspects are included in the aspects. Further, unless a technical feature is described as essential in the present specification, the technical feature may be omitted as appropriate.

DESCRIPTION OF REFERENCE NUMERALS