CATHETER

BACKGROUND

Technical Field

The present invention relates to a catheterization aid used in a fistula catheter and a fistula catheter used to supply fluids such as liquid foods and nutrients into the digestive tract of a patient. Related Art

In people with reduced ability to ingest food orally by themselves due to old age or illness, e.g., a patient, parenteral nutrition is performed, whereby liquid foods, nutrients, etc, are supplied using a fistula catheter. In parenteral nutrition, a fistula (gastric fistula) is formed in the abdomen of the patient, and a fistula catheter is attached to this fistula, and liquid foods are supplied to the patient via the fistula catheter.

Fistula catheters used in this type of parenteral nutrition can be broadly classified into the balloon type and the bumper type, depending on the shape of the part affixed inside the body.

A bumper-type part affixed inside the body that has been proposed. For example, Japanese Unexamined Patent Application Publication No. 2008-541842 appears to disclose a configuration in which wings are formed by means of multiple slits formed on the outer circumference of a tube, and a part affixed inside the body is formed by

extending compressing these wings. The part affixed inside the body forms a part (bumper) that has a diameter larger than that of the tube , because the wings bend back and forth and spread out radially like flower petals when compressed. It is configured such that the fistula catheter is affixed inside the digestive tract wall, such as the gastric wall, by this bumper. The bumper is formed using a component called a catch, whose tip changes into a hook shape. When the bumper is placed in the stomach, for example, the component called the catch is also placed in the stomach together with it. If the catch is placed in the stomach, its entirety is exposed to gastric juices, nutrients, etc. In this case, the material that forms the catch deteriorates and its strength decreases. When the strength of the catch decreases, the elasticity of the collar that forms the bumper is lost, and the bumper shape cannot be maintained, in such a case, when the patient attempts to pull out the fistula catheter, he may end up simply removing the fistula catheter.

SUMMARY

One or more aspects of the present invention can be directed to a catheterization aid used in a fistula catheter, designed to stabilize the holding of the component t hat forms t he part affixed inside the body. One or more aspects of the invention can be directed to a fistula catheter comprising a catheterization aid.

The catheterization aid according to one or more aspects of the present invention is a catheterization aid of a part affixed inside the body formed in a fistula catheter, comprising a cylindrical body, at least part of which is inserted into the part affixed inside the body, wherein the cylindrical body comprises a tip-side holder which is formed on the tip side and holds one end in the axial direction of the part affixed inside the body into which the cylindrical body is inserted, and a base-side holder which is formed on the side closer to the base than the tip-side holder and holds the other end in the axial direction of the paxt affixed inside the body into which the cylindrical body is inserted such that it can move in the axial direction on the outer circumferential surface.

In the catheterization aid according to one or more aspects of the present invention, the tip-side holder comprises at least one part that protrudes toward the outside in the radial direction.

In the catheteriza tion aid according to one or more aspects of the present invention, the tip-side holder comprises a flange-like first expanded-diameter part which is expanded in diameter toward the outside in the radial direction, and a contracted-diameter part which is formed on the base side of the first expanded-diameter part and is more contracted in diameter than the first expanded-diameter part toward the inside in the radial direction, and a second expanded-diameter part which is formed on the base side of the contracted-diameter part and is expanded in diameter toward the outside in the radial direction.

In the ca theterization aid according to one or more aspects of the present invention, the contracted-diameter part has a protuberance formed by making at least part of the outer wall of the tip-side holder protrude in the radial direction.

_ 7 _ In the catheterization aid according to one or more aspects of the present invention, the second expanded-diameter part has a protuberance formed by making at least pari of the outer circumference of the second expanded-diameter part stand up in the tip direction,

In the catheterization aid according to one or more aspects of the present invention, a fastener which fastens one end in the axial direction of the part affixed inside the body to the tip-side holder from the outer circumference side is provided.

in the catheterization aid according to one or more aspects of the present invention, at least part of the outer circumferential surfa ce of the base-side holder has a tapered shape that tapers from the tip side toward the base side.

In the catheterization aid according to one or more aspects of the present invention, an expanded-diameter part which is expanded in diameter toward the outside in the radial direction is provided on at least part of the outer circumferential surface of the base-side holder, and it has a tapered shape that tapers from its expanded-diameter part toward the base side.

In the catheterization aid according to one or more aspects of the present invention, through-holes that enable fluid between the tip-side holder and the base-side holder to flo are formed in at least part of the wall surface.

In the catheterization aid according to one or more aspects of the present invention, the diameter of the inner cavity of the cylindrical body is determined based on the diameter of the fitting part of the extender inserted into the inner cavity of the cylindrical body.

in the catheterization aid according to one or more aspects of the present invention, an internal protuberance is formed in the inner cavity of the cylindrical body, and by this internal protuberance, the fitting part of the extender inserted into the inner cavity of the cylindrical body is locked.

According to one or more aspects of the present invention, in a fistula catheter comprising the catheterization aid, a catheter part comprising a tube, and a part affixed inside the body which is formed on the distal end of the catheter part and is placed inside the digestive tract, the part affixed inside the body is formed by bringing the tip side and the base side of the tube closer together in the state where the tip part of the tube is affixed to the tip- side holder of the catheterization aid, w hereby part of the tube extends tow ard the outside in the radial direction, and furthermore, is bent to the opposite side and deformed into a shape that extends toward the inside in the radial direction, and the tube is held by the base-side holder on the base side from the deformation position of the tube,

The catheterization aid according to one or more aspects of the present invention has a cylindrical body comprising a tip-side holder which is formed on the tip side and holds one end in the axial direction of the part affixed inside the body into which the cylindrical body is inserted, and a base-side holder which is formed on the side closer to the base than the tip- side holder and holds the other end in the axial direction of the part affixed inside the body into which the cylindrical body is inserted. As a result, in the state where the other end in the axial direction of the formed part affixed inside the body is held by the tip-end holder, the holding of one end and the other end of the part affixed inside the body can be stably maintained without the outer circumferential surfaces of the tip-side holder and base-side holder, e.g., the holders of the part affixed inside the body, being exposed to gastric juices, nutrients, etc. The shape of the part affixed inside the body can be stably maintained without dependence on, for example, the elasticity of the material that forms the part affixed inside the body.

in the catheterization aid according to one or more aspects of the present invention, the tip-side holder has at least one part that protrudes toward the outside in the radial direction. One end of the part affixed inside the body can be held by a relatively simple structure.

In the catheterization aid according to one or more aspects of the present invention, the tip-side holder comprises a flange-like first expanded-diameter part which is expanded in diameter toward the outside in the radial direction, and a contracted-diameter part which is formed on the base side of the first expanded-diameter part and is more contracted in diameter than the first expanded-diameter part toward the inside in the radial direction, and a second expanded-diameter part which is formed on the base side of the contracted-diameter part and is expanded in diameter toward the outside in the radial direction. One end of the part affixed inside the body can be held by a relatively simple structure.

In the catheterization aid according to one or more aspects of the present invention, the contracted-diameter part has a protuberance formed by making at least part of the outer wall of the tip-side holder protrude in the radial direction. One end of the part affixed inside the body can be held by a relatively simple structure. In the catheterization aid according to one or more aspects of the present invention, the second expanded-diameter part has a protuberance formed by making at least pari of the outer circumference of the second expanded-diameter part stand up in the tip direction, One end of the part affixed inside the body can be caught and held by a relatively simple structure.

In the catheterization aid according to one or more aspects of the present invention, a fastener which fastens one end in the axial direction of the part affixed inside the body to the tip-side holder from the outer circumference side is provided. One end of the part affixed inside the body can be held more firmly.

In the catheterization aid according to one or more aspects of the present invention, at least part of the outer circumferential surface of the tip-side h older has a tapered shape that tapers from the tip side toward the base side. The other end of the part affixed inside the body can be held by a relatively simple structure.

In the catheterization aid according to one or more aspects of the present invention, an expanded-diameter part which is expanded in diameter toward the outside in the radial direction is pro vided on at least part of the outer circumferential surface of the tip-side holder, and it has a tapered shape that tapers from its expanded-diameter part toward the base side. The other end of the part affixed inside the body can be held more firmly.

In the catheterization aid according to one or more aspects of the present invention, through-holes that enable fluid between the tip-side holder and the base-side holder to flow are formed in at least part of the wall surface. Fluid can be supplied stably and multi- directionaily.

In the catheterization aid according to one or more aspects of the present invention, the diameter of the inner cavity of the cylindrical body is determined ba sed on the diameter of the fitting part of the extender inserted into the inner cavity of the cylindrical body. The configuration of the inner cavity of the catheterization aid can be simpl ified in accordance with the configuration of the extender. Also, locking with the extender can be made more firm while having a simple configuration.

In the catheterization aid according to one or more aspects of the present invention, an internal protuberance is formed in the inner cavity of the cylindrical body, and by this internal protuberance, the fitting part of the ex tender inserted into the inner cavity of the cylindrical body is locked. The configuration of the inner cavity of the catheterization aid can be simplified. Locking with the extender can be made more firm while having a simple configuration.

According to one or more aspects of the present invention, in a fistula catheter comprising the catheterization aid, a catheter part comprising a tube, and a part affixed inside the body which is formed on the distal end of the catheter part and is placed inside the digestive tract, the part affixed inside the body is formed by bringing the tip side and the base side of the tube closer together in the state where the tip part of the tube is affixed to the tip- side holder of the catheterization aid, whereby part of the tube extends toward the outside in the radial direction, and furthermore, is bent to the opposite side and deformed into a shape that extends toward the inside in the radial direction, and the tube is held by the base-side holder on the base side from the deformation position of the tube. The shape of the part affixed inside the body can be stably maintained. Further, even if the fistula catheter is pul led tight from the surface of the body, the shape of the part affixed inside the body can be maintained, and therefore it is difficult to remove the fistula catheter from the fistula.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 (a) and 1(b) are schematic diagrams illustrating configuration examples of a catheterization aid;

FIG. 2 is a schematic diagram showing parts of a fistula catheter that uses a catheterization aid according to one or more embodiments of the in vention;

FIGS. 3(a)-3(c) are schematic diagrams illustrating in cross-section an operation that extends a part affixed inside the body of a fistula catheter according to one or more embodiments of the invention;

FIG. 4 is a schematic diagram showing a perspective view of a fistula catheter according to according to one or more embodiments of the invention;

FIG. 5 is a schematic diagram showing a side view of a fistula catheter according to one or more embodiments of the invention;

FIG. 6 is a schematic diagram showing a plan view of a fistula catheter according to one or more embodiments of the in vention; FIG. 7 is a schematic diagram showing bottom view of a fistula catheter according to one or more embodiments of the invention;

FIG. 8 is a schematic diagram showing a side view in an extended state of a fistula catheter according to one or more embodiments of the invention;

FIG. 9 is a schematic diagram showing a cross-sectional view along line A -A of FIG.

8 according to one or more embodiments of the invention;

FIG. 10 is a schematic diagram showing insertion/removal operation of a fistula catheter according to one or more embodiments of the invention;

FIG. 11 is a schematic diagram showing a catheterized state of a fistula catheter according to one or more embodiments of the invention;

FIG. 12 is a schematic diagram showing a cross-sectional view illustrating another configuration example of a catheterization aid according to one or more embodiments of the invention;

FIGS. 13(a) and 13(b) are schematic diagrams illustrating yet another configuration example of a catheterization aid according to one or more embodiments of the invention;

FIGS. 14(a) and 14(b) are schematic diagrams illustrating yet another configuration example of a catheterizati on aid according to one or more embodiments of the inventi on;

FIG. 15 is a schematic diagram showing a cross-sectional view illustrating yet another configuration example of a catheterization aid according to one or more

embodiments of the invention;

FIG. 16 is a schematic diagram showing a cross-sectional view illustrating yet another configuration example of a catheterization aid according to one or more

embodiments of the invention;

FIGS. 17(a)- 17(c) are schematic diagrams illustrating an example of a tip-side holder of a catheterization aid according to one or more embodiments of the invention; and

FIGS. 18(a)- 18(b) are schematic diagrams illustrating another example of a tip-side holder of a catheterization aid according to one or more embodiments of the invention,

DETAILED DESCRIPTION

Non-limiting embodiments of the present invention will be exemplarily described below with reference to the accompanying drawings. FIG. 1 is a schematic view illustrating a configuration example of the catheterization aid 60 according to an embodiment, FIG. 17 is an explanatory diagram illustrating an example of the tip-side holder 63, FIG. 18 is an explanatory diagram illustrating another example of the tip-side holder 63, The configuration of the catheterization aid 60 will be described based on FIG. 1 , FIG. 17 and FIG. 18. FIG. 1(a) is a side view of the

catheterization aid 60, and FIG. 1(b) is a cross-sectional view of the catheteriza tion aid 60. The catheterization aid 60 has the function of contributing to maintaining the shape of the so- called bumper-shaped part affixed inside the body formed on the tip side of the fis tula catheter, Note that in the drawings, including FIG. 1, the relative sizes of the constituent components may differ from actual.

The catheterization aid 60 is constructed of a metal such as stainless steel or titanium, or a resin such as polyurethane. It has an inner cavity for passing fluids through to the inside. Note that the constituent materials of the ca theterization aid 60 are not particularly limited, but because they are placed in, for example, the stomach, they may be constructed of biologically compatible materials that are not readily degraded by, for example, gastric juices and nutrients.

As show ^r n in FIG. 1 (a), the catheterization aid 60 has an outside diameter which is larger tha the inside diameter of the component formed by the part affixed inside the body (for example, a component of which at least part is formed into a cylindrical shape by deformable resin material, which is attached to the tube or the tip of the tube that forms the fistula catheter; called "component forming the part affixed inside the body" hereinafter), and it has a cylindrical body 60 A of which at least part is inserted in the forma tion side of the part affixed inside the body. This cylindrical body 60A is constructed of a tip-side holder 63, a base-side holder 64 and an intermediate part 66. Note that "tip" means the side inserted inside the body, indicating the bottom side of the drawings in FIG. 1 , "Base" means the side opposite the tip, indicating the top side of the drawings in FIG. 1.

The tip-side holder 63 is formed on the tip side of the cylindrical body 60A, and has the function of holding the tip part of the component forming the part affixed inside the body by adhesion with glue or by locking. The base-side holder 64 is formed on the side closer to the base than the tip-side holder 63 of the cylindrical body 60A, and has the function of holding the component forming the part affixed inside the body such that it can move in the axial direction on the outer circumferential surface. The intermediate part 66 is formed at the position that connects the tip-side holder 63 and the base-side holder 64,

The tip-side holder 63 comprises a flange-like first expanded-diameter part 63a which is expanded in diameter toward the outside in the radial direction and is abutted by the tip part of the component forming t he part affixed inside the body, a contracted-diameter part 63b which is formed on the base side of the first expanded-diameter part and is more contracted in diameter than the first expanded-diameter part toward the inside in the radial direction, and a second expanded-diameter part 63 c which is formed on the base side of the contracted-diameter part and is expanded in diameter toward the outside in the radial direction. Thus, it is possible to easily hold the tip part of the component forming the part affixed inside the body without the catheterization aid 60 having a comple shape,

The first expanded-diameter part 63a has a shape that gently expands in diameter toward the tip, and is configured such that the fistula and digestive tract wall are not readily damaged by the first expanded-diameter part 63a during insertion/removal or catheterization. The first expanded-diameter part 63a is arranged in a position that protrudes from the tip part of the component forming the part affixed inside the body. Note that the tip-side holder 63 and the component forming the part affixed inside the body are locked by frictional force, but the two may be adhered using glue, for example, so as to hold them more firmly.

At least part of the contracted-diameter part 63b abuts the inner wall of the tip part of the component forming the part affixed inside the body, and it contributes to holding and affixing its tip part. The contracted-diameter part 63b may form a groove, etc., formed in a circumferential shape on the outer circumference of the tip-side holder 63.

The second expanded-diameter part 63c has a shape the gently expands in diameter toward the base, and has the function of assisting in stabilizing the shape of the formed part affixed inside the body, The second expanded-diameter par 63c is arranged on the tip-side forming part of the part affixed inside the body inside the inner cavity of the component forming the part affixed inside the body.

Note that the shape of the tip-side holder 63 is not limited to that shown in FIG. 1. The tip-side holder 63 may have any shape, provided that it has the function of holding the tip part of the component forming the part affixed inside the body. For example, as shown in FIG. 17(a), protrusions 63f may be formed on at least part of the tip-side holder 63, These protrusions 63f are formed such that they can catch at least part of the tip part 10A of the tube 10. The protrusions 63f may be formed such that at least part of the outer wall of the tip- side holder 63 protrudes in the radial direction. Also, the protrusions 63f may be formed along the entire circumference of the tip-side holder 63 as shown in FIG. 17(b), or may be formed on part of the tip-side holder 63 as shown in FIG. 17(c).

To give another example, the tip-side holder 63 may be shaped such that multiple stages of different diameters are layered on top of each other such that the diameter expands in a step-wise manner from the tip to the base, as shown in FIG. 18(a). Or, the tip-side holder 63 may be shaped such that multiple stages of different diameters are layered on top of each other such that the diameter contracts in a step-wise manner from the tip to the base, as shown in FIG. 18(b). In either of the tip-side holders 63 formed in the shapes shown in FIG. 18, at least some of the stages protrude toward the outside in the radial direction, so as to function in the same way as the protrusions 63f shown in FIG. 17.

The base-side holder 64 holds the inner circumferential surface of the component forming the part affixed inside the body such that the component forming the part affixed inside the body can move in the axial direction. Here, "held such that it can move in the axial direction" means that the base-side holder 64 hol ds a different position of the inner circumferential surface of the component forming the part affixed in side the body depending on the state of the component forming the part affixed inside the body, e.g., the extended state or the state where the extended state has been released. However, in the state where the component forming the part affixed inside the body has been extended, such as in the state where the part affixed inside the body has not been formed, the base-side holder 64 may hold the inner surface of the component forming the part affixed inside the body , but it does not necessarily ha ve to hold the inner surface of the component forming the part affixed inside the body. On the other hand, in the state where the component forming the part affixed inside the body has been contracted, such as in the state where the part affixed inside the body has been formed, the base-side holder 64 can hold the inner surface of the component forming the part affixed inside the body, in this embodiment, the state where the outside diameter of die base-side holder 64 is larger than the inside diameter of the component forming the part affixed inside the body is shown, and the inner circumferential surface of the component forming the part affixed inside the body is held by the base-side holder 64 by the factional force arising between the base-side holder 64 and the inner circumferential surface of the component forming the part affixed inside the body.

The intermediate part 66 is the part that connects the tip-side holder 63 and the base- side holder 64 in the catheterization aid 60. It is equivalent to the position not contacted by the component forming the part affixed inside the body when the part affixed inside the body has been formed. Thus, if through-holes 67 that enable fluids to flow through the

intermediate part 66 are formed so as to penetrate through part of the wail of t he

catheterization aid 60, the flow of nutrients can be improved. A plurality of these through- holes 67 may be formed along the entire circumference, as shown in FIG. 1 .

As shown in FIG. 1(b), an internal protuberance 65 which protrudes toward the inside in the radial direction may be provided on the inner circumferential surface of the catheterization aid 60, The internal protuberance 65 has the function of fitting together with the tip part of the extender described below. Note that the state where an internal

protuberance 65 has been formed is shown in the example here, but it does not necessarily have to be provided, as long as locking is possible by the tip part of the extender inserted in the catheterization aid 60.

If the catheterization aid 60 configured in this way is used, the tip part of the component forming the part affixed inside the body is held by the tip-side holder 63, and the base side which is closer than the formation position of the part affixed inside the body is held by the base-side holder 64. Therefore, even when the catheterization aid 60 is inside the digestive tract wall where it is exposed to contents (including liquid foods, nutrients, etc.) and bodily fluids which move forcefully, the outer circumferential surfaces of the tip-side holder 63 and base-side holder 64 are not exposed to contents and bodily fluids in the state where the other side in the axial direction of the formed part affixed inside the body is held by the base-side holder 64. Thus, in accordance with one or more advantageous aspects of the invention, the shape of the part affixed inside the body can be more readily maintained, the catheterized state of the fistula catheter can be well maintained, and unintentional removal, such as removal by the patient himself, can be curtailed or reduced.

Further, when the catheterization aid 60 is inserted into the component forming the part affixed inside the body , the outer circumferential surface of the catheterization aid 60 is sealed tight in the inner cavity of the component forming the part affixed inside the body. Gastric juices and nutrients do not readily enter between the catheterization aid 60 and the component forming the part affixed inside the body, and degradation of the contact surface between the catheterization aid 60 and the component forming the part affixed inside the body can be curtailed or reduced. In addition, trouble such as the catheterization aid 60 slipping out does not readily occur. As a result, the tightly sealed state between the catheterization aid 60 and the component forming the part affixed inside the body is stably maintained, and the shape of the part affixed inside the body is maintained.

FIG. 2 is a schematic diagram of the main parts of a fistula catheter 1 that uses the catheterization aid 60 according to an embodiment. FIG, 3 is a schematic diagram illustrating in cross-section the operation that extends the part affixed inside the body B of the fistula cath eter 1 according to an embodiment. FIG. 4 is a perspecti ve view of the fistula catheter 1. FIG. 5 is a side view of the fistula catheter 1. FIG. 6 is a plan view of the fistula catheter 1. FIG. 7 is a bottom view of the fistula catheter 1. FIG. 8 is a schematic side view illustrating the extended state of the fistula catheter 1. FIG . 9 is a schematic cross-secti onal view as seen along line A-A of FIG. 8. FIG. 10 is a drawing which explains the insertion/removal operation of the fistula catheter 1. FIG. 11 is a drawing which explains the catheterized state of the fistula catheter 1. The fistula catheter 1 that uses the catheterization aid 60 will be explained in detail based on FIG. 2 through FIG. 1 1 .

As shown in FIG. 10, the fistula catheter 1 is mounted in a fistula 73 formed so as to penetrate through the patient's abdominal wall 71 and digestive tract wall 72. This fistula catheter 1 comprises a catheter part A and a part affixed inside the body B, as shown in FIG. 2. The catheter part A is inserted into the fistula 73, and has the function of allowing fluids such as nutrients to flow through. The part affixed inside the body B is positioned inside the digestive tract wall 72, such as the gastric wall, when the fistula catheter 1 is placed in the fistula 73 of the patient, and it has the function of curtailing removal of the fistula catheter 1 from the fistula 73 of the patient. Also, the fistula catheter 1 comprises the catheterization aid 60 described above. Note that the case where a tube is used as the component forming the part affixed inside the body is described here as an example.

Note that in the descriptions below, "proximal" means the end of the catheter part A of the fistula catheter 1 in the state w ^r here it is arranged in the fistula 73, indicating the top

- ! z - side of the drawing in FIG. 2, "Distal" means the side opposite the proximal side, indicating the bottom side of the drawing in FIG. 2.

The fistula catheter 1 comprises a tube 10. The tube 10 is constructed of a resin material such as polyurethane resin, polyvinyl chloride resin, silicone resin and has an inner cavity for passing fluids through to the inside. The material of the tube 10 is not limited to the above materials, but a material that can be thermoformed and that has flexibility even after thermo formation is used.

As shown in FIG. 8 and FIG. 9, multiple slits 11 that pass through between the inside and outside of the tube are provided al ong the axial direction in the tube 10, In this embodiment, the case where there are three slits is shown as an example. The length of the slits 11 may be determined in accordance with, for example, the shape and size of the part affixed inside the body B without particular limitation. The slits 11 may be provided in parallel with the axial direction of the tube, but they may also be provided at an angle to the axial direction. Also, in this embodiment, the three slits 1 1 are provided at locations that divide the circumferential wall of the tube 10 into three substantially equal parts.

The circumferential wail of the tube 10 is divided into multiple parts by the slits 11, and three belts are formed by this division. Each belt 12 is in a state where it is connected into one by means of the circumferential wall of the tube at its top end and bottom end. Also, when the distal end of the tube 10 is pushed toward the proximal end such that the distal end and proximal end of each belt 12 approach each other in the axial direction, the belts 12 are bent due to their elasticity, and wings 13 are formed, as shown in FIG. 2 and FIG. 3.

As shown in FIG. 2, the tube 10 has three wings 13. The wings 13 extend toward the outside in the radial directi on from the proximal end of the tube 10, and they also ha ve a bent part 16 which bends in the opposite direction, and continuing from the bent part 16. they have a shape that extends toward the inside in the radial direction. Note that the shape of the wings 13 may be a shape that can be deformed due to the elasticity of the component forming the part affixed inside the body such as a tube, without particular restriction, Note that the bent part 16 is bent so as to form an arc whose cross-section is substantially U-shaped, but it is not limited to this, and may be bent at an acute angle.

The wings 13 are formed by pushing the distal end of the tube 10 in the state shown in FIG. 8 so that it is brought closer to the proximal end, thereby bending the belts 12 toward the outside in the radial direction. In so doing, the part affixed inside the body B having a shape as shown in FIG. 2 through FIG. 7 is formed, and therefore, the fistula catheter 1 is produced by thermoformation in this state. Here, the case where the shape of the part affixed inside the body B is determined by thermoformation of the tube 10 is described as an example, but it is not limited to this. The shape of the part affixed inside the body 13 is not necessarily predetermined by thermofoiiiiation, because if the catheterization aid 60 is used, the shape of the part affixed inside the body B can be held by the catheterization aid 60.

The tube 10 is constructed of a material that is flexible even after thermoformation. Therefore, by bringing the distal end 15 of the tube 10 farther from the proximal end 14 in the axial direction, the tube 10 almost immediately goes into the extended state (refer to FIG. 8). Also, when this extended state is released, it again goes into the state where the wings 13 are formed, as shown in FIG. 2, Note that if a tube 10 that was not thermoformed is used, it does not return to a state where wings 13 are formed even when the extended state is released. In this case, the wings 13 are formed by pulling the catheterization aid 60 toward the technician using an extender 50 described below, and the part affixed inside the body B is formed due to the fact that the other end in the axial direction of the part affixed insi de the body B is held by the base-side holder 64.

The catheterization aid 60 contributes to stabilization of the shape of the part affixed inside the body B formed due to elastic deformation of part of the tube 10, as described abo ve. The tip-side holder 63 of the catheterization aid 60 holds the tip end 1 OA (tip surface 10a and tip part inner circumferential surface 10b) of the tube 10 by adhesion or locking, and the base-side holder 64 holds the inner circumferential surface that is closer to the proximal end than the starting end P of the w ings 13 (refer to FIG. 3) on the outer circumferential surface. As a result, the tip-side holder 63 and base-end holder 64 maintain the state of the wings 13 formed by bringing the proximal end and the distal end of the tube 10 closer.

Therefore, the tip part 10A of the tube 10 is held by the tip-side holder 63, and the base side which is closer than the formation position of the part affixed inside the body is held by the base-side holder 64. Therefore, even when the catheterization aid 60 is inside the digestive tract wall 72 where it is exposed to contents (including liquid foods, nutrients, etc.) and bodily fluids which move forcefully , the outer circumferential surfaces of the tip-side holder 63 and base-side holder 64 are not exposed to contents and bodily fluids in the state where the other side in the axial direction of the formed part affixed inside the body is held by the base-side holder 64. The shape of the part affixed inside the body is more readily maintained, and the catheterized state of the fistula catheter can be well maintained, and unintentional removal, such as removal by the patient himself, can be curtailed.

Further, when the catheterization aid 60 is inserted into the tube 10, the outer circumferential surface of the catheterization aid 60 is sealed tight in the inner ca vity of the tube 10. Gastric juices and nutrients do not readily enter between the catheterization aid 60 and the tube 10, and degradation of the contact surface between the catheterization aid 60 and the tube 10 can be curtailed. In addition, trouble such as the catheterization aid 60 slipping out due to nutrients, etc., does not readily occur. As a result, the tightly sealed state between the catheterization aid 60 and the tube 10 is stably maintained, and the shape of the part affixed inside the body B is maintained.

Next, the ca theterization operation of the fistula catheter 1 configured in this way in the fistula 73 will be described. First, the extender 50 will be described, which is used for extending the part affixed inside the body B of the fistula catheter 1 and inserting the part affixed inside the body B inside the digestive tract wall 72 such as the gastric wall or intestinal wall.

As shown in FIG. 10, the extender 50 comprises a fitting part 1 provided on the tip side, an operating part 52 provided on the end on the side opposite the fitting part 51, and a shaft part 53 provided between the operating part 52 and the fitting part 1. The fitting part 51 and the shaft part 53 are configured such that they can be inserted in the inner cavity of the tube 10. In particular, the fitting part 51 can be inserted in the inner cavity of the catheterization aid 60. The operating part 52 is constructed of, for example, synthetic resin or metal, and has a shape such that a technician can apply his finger to it.

The fitting part 51 is configured such that it has the same or larger diameter as the inside diameter of the internal protuberance 65 formed in the inner cavity of the

catheterization aid 60. Also, the length in the axial direction of the fitting part 51 may be determined in accordance with the length of the internal protuberance 65 formed in the inner cavity of the catheterization aid 60. Note that when a ca theterization aid 60 that does not have an internal protuberance 65 is used, it can be configured such that the inner cavity itself of the catheterization aid 60 locks with the fitting part 51. In this case, the fitting part 51 may be configured so as to have a larger diameter than the inside diameter of the catheterization aid 60.

The fitting part 51 configured in this way is positioned inside the inner cavity of the tube 10 in the extended state. Since an internal protuberance 65 has been provided in the inner cavity of the catheterization aid 60, the fitting part 51 of the extender 50 is locked by the internal protuberance 65. When this is done, the outer surface of the fitting part 51 and the inner circumferential surface of the internal protuberance 65 are tightly sealed, and the extended state of the tube 10 is held by the frictional force arising between the outer surface of the fitting part 51 and the inner circumferential surface of the tube 10, Note that the confi guration of the extender 50 described here is an example of an extender, and this example does not limit its shape or the structure for extending the fistula catheter 1.

Next, the extension operation of the fistula catheter 1 will be described whil e referring to FIG. 3(a) through FIG. 3(c). Note that in FIG. 3, the holding parts of the tip-side holder 63 and the tube 10 and the holding parts of the base-side holder 64 and the tube 10 are emphasized with thick lines. Note that FIG. 3 shows as an example of the state where the base-side holder 64 abuts the inner circumferential surface of the tube 10, in the state where the tube 10 is extended, but it is not limited thereto, and depending on the length in the part where the slits 11 are arranged, the base-side holder 64 does not have to abut the inner circumferential surface of the tube 10 in the state where the tube 10 is extended. In short, it is acceptable as long as the base-side holder 64 can hold the inner circumferential surface of the tube 10 when the part affixed inside the body B has been formed.

As shown in FIG. 3(a), the wings 13 are in the formed sta te in the tube 10 of the fistula catheter 1 . In this state, the extender 50 is inserted into the tube 10 and the inner cavity of the catheteriza tion aid 60. The extender 50 has a fitting part 51 which is detachably affixed to the inner circumferential surface of the catheterization aid 60. Here, it has a configuration such that the two are affixed by the frictional force arising between the inner circumferential surface of the internal protuberance 65 pro vided on the catheterization aid 60 and the outer circumferential surface of the fitting part 51. When the extender 50 is inserted up to the appropriate position inside the catheterization aid 60, fictional force acts between the fitting part 50 and the internal protuberance 65 of the catheterization aid 60, and advancement of the extender 50 inside the catheterization aid 60 is stopped. In this state, if a force exceeding the frictional force with the inner circumferential surface of the tube 10 in the base-side holder 64 is applied by pushing the extender 50 in further, the affixment of the two is temporarily released. When this is done, as shown in FIG. 3(b), the catheterization aid 60, which is fit together with the fitting part 51 of the extender 50, advances toward the distal side accompanying the extender 50. Additionally, the tip part 10A of the tube 10 affixed by the catheterization aid 60 and tip-side holder 63 also advances toward the distal side. In this way, by pushing in the extender 50, the wings 13 of the tube 10 extend, so as to reach the state shown in FIG. 3(c). To realize this operation, it is configured such tha the frictional force arising between the fitting part 51 and the internal protuberance 65 of the catheterization aid 60 is larger than the frictional force arising between the base- side holder 64 and the inner circumferential surface of the tube 10. By so doing, the fistula catheter 1 goes into the extended state, and can be inserted into/removed from the fistula 73.

According to this embodiment, it has a catheterization aid 60 which is inserted inside the tube 10. This catheterization aid 60 has a base-side holder 64 which holds the tube 10 such that it can mo ve in the axial direction on the inner circumferential surface of the tube 10 on the proximal side closer than the proximal end of the slits 11 of the tube 10, and it has a tip-side holder 63 which holds the tube 10 on the distal side closer than the distal end of the slits 11 of the tube 10. In the state where the wings 13 have been formed, the shape of the wings 13 can be maintained due to the fact that the base-side holder 64 and the tip-side holder 63 are held together with the tube 10, The shape of the pari affixed inside the body B is more readily maintained, even when inside the digestive tract wall 72 which is exposed to contents and bodily fluids which move forcefully. Therefore, the catheterized state of the fistula catheter I can be well maintained, and unintentional removal, such as removal by the patient himself, can be curtailed.

Note th at the detachabl e affixment structure of the catheterization aid 60 an d the extender 50 is not limited to one that uses frictional force due the fitting part 51 and the internal protuberance 65 as described above. It may be a configuration wherein the extender 50 and the catheterization aid 60 can be affixed when the extender 50, which extends the wings 13 of the fistula catheter 1, is pushed in, and after the shape that functions as the part affixed inside the body B is formed by the catheterization aid 60, the two are separated. For example, a screw may be provided, which screws together the inner circumferential surface of the catheterization aid 60 and the outer circumferential surface near the tip of the extender 50,

Next, the catheterization operation of the fistula catheter 1 configured in this way into the fistula 73 will be described, As shown in FIG, 10, the fistula catheter 1 in the state where it has been extended by the extender 50 is inserted into the fistula 73 formed in the abdominal wall 71 and digestive tract wall 72. The diameter of the fistula catheter 1 is, at largest, the same diameter as the tube 10 in the state where the catheterization aid 60 is inserted, and the resistance is low when it passes through the fistula 73. There is little or a reduced risk of damaging the fistula 73,

When it has been inserted up to the appropriate depth, the technician pulls the extender 50 tightly toward him while pushing on the side nearest the abdominal wall 71 so that the catheter part A is not removed. By pulling with a force exceeding the frictional force between the fitting part 51 and the internal protuberance 65, the tightly sealed state between the fitting part 51 and the catheterization aid 60 is released, and the extender 50 is pulled out from inside the tube 10. Because the fistula catheter I is thermo formed, when the extender 50 is pulled out and the extended state is released, it goes into the state where the part affixed inside the body B is formed, as shown in FIG. 11. Simply by pulling out the extender 50, the fistula catheter 1 in the extended state can be put in the state where the part affixed inside the body B is formed, and operation is simple.

Note that if a tube 10 that was not thermoformed is used, it ca be configured such that the extender 50 is pulled toward the technician in the state where the catheterization aid 60 is fitted, and the other end in the axial direction of the part affixed inside the body B is held on the outer circumferential surface of the base-side holder 64 of the catheterization aid 60, and a shape that functions as the part affixed inside the body B is formed by the catheterization aid 60, after which the tightly sealed state between the extender 50 and the catheterization aid 60 is released and the extender 50 is pulled out. In this case as well, the only operation performed is to pull out the extender 50, and therefore it can be put in the state where the part affixed inside the body B has been formed by a simple operation.

The proximal end of the catheter part A of the catheter placed in the fistula 73 is in a state where it is exposed outside the body. A pait affixed outside the body is connected to the exposed proximal end of the catheter part. The part affixed outside the body may be of the type affixed to the end of the tube like a button-type catheter, or the type that detachably attaches the part affixed outside the body to the tube like a tube-type catheter. Also, any connection structure may be used to connect to the part affixed outside the body.

As shown in FIG. 11, in the fistula catheter I placed inside the digestive tract wall and in the state where the part affixed inside the body B has been formed, the top surface of the wings 13 (surface nearest the proximal end) contacts the digestive tract wall. As shown in FIG. 6, a substantial ly disk-shaped surface S is formed by the wings 13 of the tube 10 in the center of the wings 13 (such as near the outer circumferential surface of the tube 10). This surface S abuts the periphery of the fistula 73 of the digestive tract wall 72. Since it contacts the digestive tract wall 72 by means of the surface S, there is little invasion of the digestive tract wall 72. Also, if the wings 13 are given a shape that is rounded with respect to the digestive tract wall 72, their contact with the digestive tract wall is gentle, and invasion of the digestive tract wail 72 can be further reduced.

Further, when the fistula catheter 1 has been pulled tight from the side nearest the abdominal wall 71, for example, the top surface of the wings 13 is pressed up against the digestive tract wall 72, and a force acts on the wings 13 of the tube 10, which are in the radially expanded state, in a direction so as to close them. In the wings 13 of the tube 10, the bent part 16 typically moves inward in the radial direction, and the outside diameter of the wings 13 gets smaller. However, the shape of the part affixed inside the body B is maintained by the catheterization aid 60, and unintentional removal, such as removal by the patient himself, can be curtailed.

Note that when the fistula catheter 1 in the catheterized state is removed from the fistula 73, it can be pulled out with the part affixed inside the body of the fistula catheter in the extended state, by the same operation as when inserting it.

Thus, according to this embodiment, using a catheterization aid 60 constructed of a material that does not readily degrade, the state of holding of the component forming the part affixed inside the body such as the tube inside the digestive tract wall 72 is not readily released, and as a result, the shape of the part affixed inside the body B can be maintained stably for a long period. Invasion of the digestive tract wall due to deformation of the part affixed inside the body B can be further reduced. Therefore, the shape of the part affixed inside the body B can be maintained stably for a long period, and unintentional removal, such as removal by the patient himself, can be curtailed.

Additionally, the outside diameter of the fistula catheter 1 in the extended state is the outside diameter of the tube 10 (the outside diameter that has been made slightly larger by the first expanded-diameter part). The outside diameter when extended is typically smaller than that of a bumper, which is made of general synthetic resin and is typically coniigured so as to expand in diameter inside the digestive tract wall. Therefore, there is little or reduced resistance against the fistula when inserted and removed, and the risk of damaging the fistula 73 can be reduced. Also, the fistula catheter 1 is constructed of two components, the tube 10 and the catheterization aid 60, and its number of parts is small. Increases in manufacturing costs can be curtailed or reduced. Additionally, since the fistula catheter 1 can be easily extended by pulling the distal end and proximal end away from each other, its operation is simple when inserted and removed, and the burden on the technician can be reduced.

Note that in addition to the configurations described in the above embodiments, the applications described below are also possible. The number of slits 11 was three in the tube 10 described above, but it can be any number of two or more. Also, an example was shown in which the slits 11 are provided at locations that divide the circumferential wall of the tube 10 into three equal parts in the radial direction, but they can be provided at locations that do not divide it equally. In the above description, an example was shown in which the slits 1 1 were provided in order to form a belt 12 on the tube 10, These slits form a narrow gap in the tube 10, but notches rather than such slits may be provided.

Here, other configuration examples of the catheterization aid 60 will be described. FIG. 12 is a schematic cross-sectional view illustrating another configuration example of the catheterization aid 60. FIG. 13 is a schematic diagram illustrating yet another configuration example of the catheterization aid 60. FIG. 14 is a schematic diagram illustrating yet another configuration example of the catheterization aid 60. FIG. 15 is a schematic cross-sectional view illustrating yet another configuration example of the catheterization aid 60. FIG. 16 is a schematic cross-sectional view illustrating yet another configuration example of the catheterization aid 60. Note tha t FIG. 13(a) shows a schematic cross-sectional view of the catheterization aid 60, and F IG. 13(b) shows a schematic diagram of a configuration example of the tip part 10A of the tube 10. Also, FIG. 14(a) shows a schematic cross-sectional view of the catheterization aid 60, FIG. 14(b) shows a schematic diagram of a configuration example of the tip part 10A of the tube 10, and FIG. 14(c) shows a plan view of the catheterization aid 60.

As described above, the catheterization aid 60 has the function of contributing to maintaining the shape of the wings 13 of the tube 1 , for example, the shape of the part affixed inside the body B. One configuration example of the catheterization aid 60 was described based on FIG. 1 , but the configuration of the catheterization aid 60 is not limited thereto. Thus, other configuration examples of the catheterization aid 60 will be described. FIG. 12 through FIG. 14 show configuration examples of the tip-side holder 63 of the catheterization aid 60. FIG. 15 and FIG. 16 show configuration examples of the base-side holder 64 of the catheterization aid 60.

In addition to the configuration shown in FIG. 1 , the catheterization aid 60 shown in FIG. 12 also has a separate fastener 61. This fastener 61 is provided so as to fasten the tube 10 to the tip-side holder 63 from the outer circumferential side, in order to more firmly hold the tip part 10A of the tube 10. This fastener 61 ma be constructed of an O-ring, for example.

In addition to the configuration shown in FIG. 1 , the catheterization aid 60 shown in FIG. 13 also has a first protuberance 63d formed on the contracted-diameter part 63b. This first protuberance 63d is formed such that it can catch at least part of the tip part 10A of the tube 10. The first protuberance 63d may be formed by making par of the outer wall of the tip-side holder 63, such as part of the outer wall of the contracted-diameter part 63b, protrude in the radial direction. The first protuberance 63 d can have the same function as the protrusions 63f shown in FIG. 17. However, the first protuberance 63d can also serve as the protrusions 63f. In the case where this first protuberance 63d is formed in this way, a hole which is separate from the slits 11 (hole 10B shown in FIG. 13(b)) ma be formed on the tip part 10A of the tube 10, such that the first protuberance 63d is caught in the hole 10B. Note that the slits 11 may also be caught on the protuberance 63d.

In addition to the configuration shown in FIG. 1, the catheterization aid 60 shown in FIG. 14 also has a second protuberance 63e formed on the second expanded-diameter part 63c. This second protuberance 63e is formed such that it can catch at least part of the tip part 10A of the tube 10. The second protuberance 63 e is formed by making at least part of the outer circumference of the second expanded-diameter part 63c stand up in the tip direction of the tube 10. In the case where such a second protuberance 63e is formed, the slits 1 1 formed in the tube 10 may be caught on the second protuberance 63a (refer to FIG. 14(c)), Note that the second protuberance 63e may also be caught in the hole 10B as shown in FIG. 13(b).

Note that the number of first protuberances 63d and second protuberances 63e may be a number corresponding to the number of slits 11 or holes I OB formed in the tube 10, without particular limitation. Also, the first protuberance 63d may be shaped like the second protuberance 63e, or the second protuberance 63e may be shaped like die first protuberance 63d.

In addition to the configuration shown in FIG. 1, in the catheterization aid 60 shown in FIG, 15, the base-side holder 64 also has a tapered shape that gradually decreases in diameter from its tip side to the base side. Due to the base-side holder 64 having a tapered shape, insertability into the tube 10 can be improved, and the inner circumferential surface of the tube 10 can be held by insertion friction.

In addition to die configuration shown in FIG. 1, the catheterization aid 60 shown in

FIG. 16 also has an expanded-diameter part 64a provided on at least part of the outer circumferential surface of the base-side holder 64, and has a tapered sh ape that gradually decreases in diameter from the expanded-diameter pari 64a to the base side, As a result, a tapered shape can be formed having a taper angle l arger than the taper angle of the tapered shape of the base-side holder 64 shown in FIG, 15, and the inner circumferential surface of the tube 10 can be more firmly held by insertion friction. Although the diameter of the expanded-diameter part 64a is not particularly limited, it may be about the same as that of the first expanded-diameter part 63a of the tip-side holder 63, for example.

As described above, the tip-side holder 63 of the catheterization aid 60 holds the tip part lOA of the tube 10, and the outer circumferential surface of the base-side holder 64 abuts and holds the inner circumferential surface closer to the base end than the starting end P of the wings 13, As a result, the tip-side holder 63 and the base-side holder 64 maintain the state of the wings 13 formed by bringing the proximal end (tip side) of the tube 10 and the distal end (base side) closer to each other.

Thus, if a catheterization aid 60 having any of the configurations shown in FIG . 1 and

FIGS. 12-16 is used, the tip part I0A of the tube 10 is held by the tip-side holder 63, and the base side which is closer than the formation position of the part affixed inside the body B is held by the base-side holder 64. Therefore, even when the catheterization aid 60 is inside the digestive tract wall 72 where it is exposed to contents and bodily fluids which move forcefully, the outer circumferential surfaces of the tip-side holder 63 and base-side holder 64 are not exposed to contents and bodily fluids in the state where the other side in the axial direction of the formed part affixed inside the body B is held by the base-side holder 64. The shape of the part affixed inside the body B is more readily maintained, and the catheterized state of the fistula catheter 1 can be well maintained, and unintentional removal, such as removal by the patient himself, can be curtailed.

Further, when the catheterization aid 60 is inserted into the tube 10, the outer circumferential surface of the catheterization aid 60 is sealed tight in the inner cavity of the tube 10. Gastric juices and nutrients do not readily enter between the catheterization aid 60 and the tube 10, and degradation of the contact surface between the catheterization aid 60 and the tube 10 can be curtailed. In addition, trouble such as the catheterization aid 60 slipping out does not readily occur. As a result, the tightly sealed state between the catheterization aid 60 and the tube 10 is stably maintained, and the shape of the part affixed inside the body B is maintained.

Description of Reference Numerals

1 Fistula catheter; 10 Tube; l OA Tip part; 10B Hole; 10a Tip surface; 10b Tip part inner circumferential surface; 1 1 Slit; 12 Belt; 13 Wing; 14 Proximal end; 15 Distal end; 16 Bent part; 50 Extender; 51 Fitting part; 52 Operating part; 53 Shaft part; 60 Catheterization aid; 60 A Cylindrical body; 61 Fastener; 63 Tip-side holder; 63a First expanded-diameter part; 63b Contracted-diameter part; 63c Second expanded-diameter part; 63 d Expanded- diameter part; 63e Second protuberance; 63 f Protrusion; 64 Base-side holder; 64a Expanded- diameter part; 65 Internal protuberance; 66 Intermediate part; 67 Through-hole; 71

Abdominal wall; 72 Digestive tract wall; 73 Fistula; A Catheter part; B Part affixed inside body.