WO2012106200A2

WO2012106200A2 - Fistula catheter

Info

Publication number: WO2012106200A2
Application number: PCT/US2012/022896
Authority: WO
Inventors: Natsuko YAMOTO; Shigeaki Funamura
Original assignee: Tyco Healthcare Group Lp
Priority date: 2011-01-28
Filing date: 2012-01-27
Publication date: 2012-08-09
Also published as: JP5762017B2; WO2012106200A3; JP2012157385A

Abstract

To achieve a fistula catheter provided with an intracorporeal fixed part with minimal invasion into the wall of the alimentary canal. In a fistula catheter having a catheter part and an intracorporeal fixed part, the intracorporeal fixed part is provided with an inner tube and an outer tube which is provided on the outside of inner tube 10. The inner tube and the outer tube are configured with belts formed by dividing the tube wall a plurality of times in the circumferential direction, each of the inner and outer tubes have wing parts having sections that extend outwards radially. The respective wing parts of the inner tube and the outer tube are provided in corresponding positions in the axial direction and are also alternately disposed along the circumferential direction.

Description

FISTULA CATHETER

BACKGROUND

Technical Field

The present invention relates to a fistula catheter for use in supplying fluids such as liquid food or nutrients to a gastrointestinal tract of a patient.

Related Art

Enteral nutrition can be administered to persons which have a decreased ability to ingest food orally by themselves due to advance age or disease ("patients" hereinafter) to supply liquid food, nutrients, or the like, using a fistula catheter. To administer enteral nutrition, a fistula (a gastric fistula) is created in the abdomen of the patient, a fistula catheter is fitted in this fistula, and liquid food or the like is supplied to the patient through the fistula catheter.

The fistula catheters used for this kind of enteral nutrition administration can be broadly classified as so-called balloon types and bumper types, depending on the shape of the intracorporeal fixed part placed inside the body.

An intracorporeal fixed part has been proposed as the intracorporeal fixed part of a bumper type in which the intracorporeal fixed part is formed by forming wing parts by a plurality of slits formed on the outer circumference of a tube, and extending and collapsing these wing parts.

hi Japanese Patent Application Publication 2008-541842, the intracorporeal fixed part, when the wing parts are collapsed, they are bent, and a part (a bumper) having a larger diameter than the diameter of a tube is formed by their radial expansion like petals. It is configured with this bumper so that the fistula catheter is fixed to an inside wall of the alimentary canal, such as the gastric wall. However, there is a large gap between the wing parts of the fistula catheter. Thus, when the fistula catheter is pulled from the side on the surface of the body, the long side of each wing part could damage the wall of the alimentary canal, causing an ulcer in the wall of the alimentary canal resulting in a buried bumper syndrome. The gap between the wing parts can be shortened by shortening the width of the wing parts, i.e., increasing the number of slits formed in the tube. If this is done, it is assumed that this would also make it more difficult for the wing parts to eat into the wall of the alimentary canal than when the gap between the wing parts is bigger. However, the resistance of the wing parts to the wall of the alimentary canal decreases because of their small size, and the fistula catheter could end up coming out of the fistula by the easy extension of the wing parts when, for example, it is pulled from the side on the surface of the body. SUMMARY

One or more aspects of the present invention provides a fistula catheter with an intracorporeal fixed part with minimal invasion into the wall of the alimentary canal. One or more aspects of the invention can be directed to a fistula catheter with an intracorporeal fixed part that is difficult to release from its fixed state, even by pulling from the side on the surface of the body.

One or more aspects of the present invention can be directed to a fistula catheter having a catheter part and an intracorporeal fixed part, the intracorporeal fixed part being formed on the distal side of the catheter part and placed witliin the wall of the alimentary canal. The intracorporeal fixed part can have an inner tube and an outer tube, the outer tube being provided on the outside of the inner tube; the inner tube and outer tube being configured with belts formed by dividing the tube wall a plurality of times in the circumferential direction and having wing parts having sections that extend outwards radially; and the wing parts of the inner tube and the wing parts of the outer tube being provided in corresponding positions in the axial direction as well as being alternately disposed along the circumferential direction.

In accordance with some embodiments pertinent to one or more aspects of the invention, the whig parts of the outer tube and inner tube of the fistula catheter can be configured by bending or curving at least a part of the belts by moving the distal side and the proximal side of the belts towards each other in the axial direction.

In accordance with some embodiments pertinent to one or more aspects of the invention, the outer tube and inner tube of the fistula catheter can take on a straight configuration by extending them so that the proximal end and distal end separate from each other, and they are deformably formed so that sections are formed that extend outwards radially by moving the distal end and proxmial end towards each other to release the extended state.

In accordance with some embodiments pertinent to one or more aspects of the invention, the whig parts of the outer tube and inner tube of the fistula catheter have curved parts that curve towards the distal side or the proximal side in the axial direction.

In accordance with some embodiments pertinent to one or more aspects of the invention, the inner tube of the fistula catheter is longer on the proximal side than the outer tube and is configured at a length at which the proximal end of the inner tube protrudes on the side on the surface of the body when it has been placed in the fistula.

hi accordance with some embodiments pertinent to one or more aspects of the invention, the outer tube of the fistula catheter is longer on the proximal side than the inner tube and is configured at a length at which the proximal end of the outer tube protrudes on the side on the surface of the body when it has been placed hi the fistula. In accordance with some embodiments pertinent to one or more aspects of the invention, the fistula catheter is provided with an inner cylinder inserted inside the inner tube, said inner cylinder having a fixed part that is movably fixed in the axial direction to the inner surface of the inner tube at a position more on the proximal side than the wing parts of the inner tube; and a fixated part fixated to the inner surface of the inner tube at a position more on the distal side than the end part of the distal side with slits or cuts in the inner tube.

In accordance with some embodiments pertinent to one or more aspects of the invention, the wing parts of the inner tube and the wing parts of the outer tube are alternately disposed along the

circumferential direction so that at least a part of the wing parts of the inner tube or the wing parts of the outer tube is positioned at the gap between the wings parts of the other side. Thus, invasion into the patient can be inhibited by minimizing the area of the gap in contact with the wall of the alimentary canal and making it difficult for the wing parts to eat into the wall of the alimentary canal. In addition, the wing parts of the inner tube can inhibit the wing parts of the outer tube from trying to close when the fistula catheter is pulled from the side on the surface of the body, and this makes it difficult for the fistula catheter to come out of the fistula.

In accordance with some embodiments pertinent to one or more aspects of the invention, the wing parts of the outer tube and inner tube of the fistula catheter are configured by bending or curving at least a part of the belts by moving the distal side and the proximal side of the belts towards each other in the axial direction. The structure is relatively simple since a part of the tube bends or curves, so a fistula catheter can be achieved with a small production cost because there are a small number of parts.

In accordance with some embodiments pertinent to one or more aspects of the invention, the fistula catheter according to the present invention takes on an almost straight state just by extending it, and in this state, it can be mserted into or removed from the fistula. Because it takes on an almost straight state, the resistance during removal is low, and the risk of damaging the fistula can be reduced. In addition, both the insertion/removal of the flsftila catheter and its placement can be performed by releasing the extension/extension, so the procedure is simple and easy, and the practitioner's burden can be reduced.

In accordance with some embodiments pertinent to one or more aspects of the invention, the wing parts of the outer tube and inner tube of the fistula catheter have curved parts that curve towards the distal side or the proximal side in the axial direction. Thus, when the fistula catheter has been placed in the fistula, the middle of the curved parts of the wing parts come into contact with the wall of the alimentary canal, so a strike against the wall of the alimentary canal is softened, and invasion into the wall of the alimentary canal can be reduced. In accordance with some embodiments pertinent to one or more aspects of the invention, the inner tube of the fistula catheter is longer on the proximal side than the outer tube and is configured at a length at which the proximal end of the inner tube protrudes on the side on the surface of the body when it has been placed in the fistula. Thus, even supposing the inner tube protruding to the side on the surface of the body is pulled, the wing parts of the outer tube inside the wall of the alimentary canal have a bigger diameter and become a retainer, and it is difficult for the fistula catheter to come out of the fistula.

In accordance with some embodiments pertinent to some aspects of the invention, the outer tube of the fistula catheter is longer on the proximal side than the inner tube and is configured at a length at which the proximal end of the outer tube protrudes on the side on the surface of the body when it has been placed in the fistula. Thus, there is no bump due to the difference in the outer diameter of the inner tube on the outer surface of the fistula catheter, so the resistance during insertion into or removal from the fistula can be reduced, and the risk of invasion into the fistula can be reduced. Because the inner cylinder is fixed to the inner surface of the inner tube on the proximal side and the distal side of the wing parts, the maintenance of the wing parts of the inner tube of the fistula catheter according to the present invention in a bent state is reinforced, and a fistula catheter can be achieved for which it is difficult for the fistula catheter to come out of the fistula.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a perspective view showing a fistula catheter according to one or more aspects of the invention;

Fig. 2 is a schematic illustration showing a side, elevational view of a fistula catheter according to one or more aspects of the invention;

Fig. 3 is a schematic illustration showing a top view of a fistula catheter according to one or more aspects of the invention;

Fig. 4 is a schematic illustration showing a base or end view of a fistula catheter according to one or more aspects of the invention;

Fig. 5 is a schematic illustration showing a side, elevational view of a part of a fistula catheter according to one or more aspects of the invention;

Fig. 6 is a schematic illustration showing a side schematic view of a fistula catheter in an extended state according to one or more aspects of the invention;

Fig. 7 is a schematic illustration showing a side, elevational view of a portion of a fistula catheter in the extended state according to one or more aspects of the invention;

Fig. 8 is a schematic illustration showing a sectional view along arrow A-A of Fig. 6, according to one or more aspects of the invention; Fig. 9 is a schematic illustration showing a fistula catheter during an insertion or removal operation according to one or more aspects of the invention;

Fig. 10 is a schematic illustration showing a portion of a fistula catheter in place according to one or more aspects of the invention;

Fig. 11 is a schematic illustration showing a part of a fistula catheter according to one or more aspects of the invention;

Fig. 12(a)- 12(c) are sectional schematic illustrations depicting an operation of the fistula catheter according to one or more aspects of the invention;

Fig. 13 is a schematic illustration showing a perspective view of a portion of a fistula catheter according to one or more aspects of the invention;

Fig. 14 is a schematic illustration showing an example of deformation of a portion of a fistula catheter according to one or more aspects of the invention;

Fig. 15 is a schematic illustration showing an example of deformation of a portion of a fistula catheter according to to one or more aspects of the invention;

DETAILED DESCRIPTION

Embodiment 1.

Fig. 1 is a perspective view of fistula catheter I according to embodiment 1 in accordance with one or more aspects of the invention. Fig. 2 is a side view of the fistula catheter 1 . Fig. 3 is a top view of the fistula catheter 1. and Fig. 4 is a base view of the fistula catheter 1. Fig. 5 is a side view of an inner tube 10 of fistula catheter 1 according to embodiment 1 in accordance with one or more aspects of the invention. Fig. 6 is a side schematic view illustrating an extended state of fistula catheter 1. Fig. 7 is a sectional schematic view of the main parts in the extended state of the same fisttila catheter 1. Fig. 8 is a sectional schematic view along arrow A-A of Fig. 6. Further, in each of the drawings, the magnitude relation between each of the components may differ from the actual object.

Fistula catheter 1 can be fitted in fistula 73, which is formed so that it penetrates both abdominal wall 71 of the patient and alimentary canal wall 72 (see Fig. 10).

As shown in Fig. 1 , fistula catheter 1 is provided with both catheter part A and intracorporeal fixed part B. Catheter part A is inserted into the fistula, and it functions to pass fluids such as nutrients through. When fistula catheter 1 is placed in fistula 73 of the patient, intracorporeal fixed part B is located within the alimentary canal wall 72, such as the gastric wall, and it functions to prevent fistula catheter 1 from coming out of fistula 73 of the patient.

Further, in the description below, "proximal" refers to the side with catheter part A of fistula catlieter 1 when it has been fitted in fistula 73. This is shown by the upper side of the drawing in Fig. 1. In addition, "distal" refers to the side opposite the proximal side, and it is shown by the lower side of the drawing in Fig. 1.

As shown in Fig. 6, fistula catheter 1 is provided with inner tube 10 and outer tube 20, which is provided on the outside of the inner tube.

Inner tube 10 and outer tube 20 are composed of resin materials, such as polyurethane resin, polyvinyl resin, silicone resin, or the like, and they have a lumen for passing fluids through to the interior. The materials of inner tube 10 are not restricted to the above materials, but materials that can be thennally formed and still having flexibility after thermal forming.

As shown in Fig. 6 and Fig. 7, inner tube 10 is inserted into outer tube 2 so that its distal end 15 is placed at the same height as distal end 25 of outer tube 20. Fluids such as nutrients or the like can be passed through the lumen of inner tube 10. In addition, projecting part 18 that projects radially inward is formed on the inner surface near distal end 15 of inner tube 10. Proj ecting part 18 functions to lock the tip end of extension tool 50 described hereinafter.

The inside diameter of outer tube 20 is configured to be approximately the same size or slightly larger than the outer diameter of inner tube 10. The outer surface of inner tube 10 is inserted into outer tube 20, and it touches the inner surface of outer tube 20. In this embodiment 1, the inner tube 10 is longer than outer tube 20 and is configured at a length at which proximal end 14 of inner tube 10 protrudes on the side on the surface of the body when it has been placed in fistula 73 (see Fig. 10).

As shown in Fig. 7, the imier surface of outer tube 20 and the outer surface of imier tube 10 are fixed to each other by a fixing means, such as an adhesive, at two places on proximal side fixed part 31 and distal side fixed part 32. Further, proximal side fixed part 31 and distal side fixed part 32 are drawn with a bold line in Fig, 7 for the purpose of description. Proximal side fixed part 31 and distal side fixed pail 32 are only separated by a fixed distance in the axial direction. For convenience, the section between proximal side fixed part 31 and distal side fixed part 32 will now be called intermediate part 33. In this intermediate part 33, the inner surface of outer tube 20 is not fixed to the outer surface of inner tube 10.

As shown in Figs. 6-8, a plurality of slits 11 that connect the inside and outside of the tube are provided along the axial direction in intermediate part 33 of inner tube 10. A plurality of slits 21 that connect the inside and outside of the tube are also provided along the axial direction in intermediate part 33 of outer tube 20. In embodiment 1, there are three of both slits 1 1 and slits 21. The length of slits 1 1 and slits 21 may be the length of intermediate part 33 or shorter. Slits 1 1 and slits 21 can be provided parallel to the axial direction of the tube, but they may also be provided at an incline to the axial direction. In addition, each of the three slits 11 in embodiment 1 are provided at locations that approximately trisect the peripheral wall of inner tube 10. Likewise, the three slits 21 are provided at locations that approximately trisect the peripheral wall of outer tube 20. Also, as shown in Fig. 8, slits 1 1 of inner tube 10 and slits 21 of outer tube 20 are alternately disposed so that their positions in the circumferential direction differ.

The peripheral walls of inner tube 10 and outer tube 20 are divided several times by these slits 1 1 and slits 21, respectively, and the three belts 12 and belts 22 are each fonned by these divisions. Because slits 11 and slits 21 are only provided in intermediate part 33, each of these belts 12 and 22 maintain their connections at their upper ends and lower ends to form one peripheral wall of the tube, hi addition, belts 22 are placed radially outside of belts 12, and belts 12 and belts 22 are in a positional relationship corresponding to the axial direction. When the distal end of inner tube 10 and the distal end of outer tube 20 are pushed towards the proximal side to bring the distal side and proximal side of belts 12 and belts 22 close together, wing parts 13 and wing parts 23 are formed, as shown in Fig. 1 and Fig. 2, by the bending of belts 12 and belts 22 via their elasticity.

As shown in Figs. 1-4, outer tube 20 is provided with three wing parts 23. These wing parts 23 have bent parts 26 that extend radially outwards from the proximal side of outer tube 20 and bend back in the opposite direction, and they have a shape that extends radially inward in connection to these bent parts 26. Namely, because each belt 22 bends in bent part 26, each belt 22 is folded over and forms a shape in which the top and bottom parts overlap. In embodiment 1 , bent part 26 is bent in an arc shape so that the cross section forms a U-shape, but it may also be bent at an acute angle.

In addition, wing parts 23 are positioned closer to the outer wall of outer tube 20 than bent parts 26, and curved parts 27 are provided that curve in the axial direction toward the distal side.

hi addition, inner tube 10 is also provided with three wing parts 13. Wing parts 13 have a shape that is similar to wing parts 23 of the outer tube. They have bent parts 16 that extend radially outwards from the proximal side of inner tube 10 and bend back in the opposite direction, and they have a shape that extends radially inward in comiection to these bent parts 16. Further, because the outside diameter of inner tube 10 is smaller than outer tube 20, the width of belts 12 is also smaller than the width of belts 22 of outer tube 20, so the width of wing parts 13 is also smaller than the width of wing parts 23 of outer tube 20.

As shown in Fig. 1 - 4, the wing parts 23 of outer tube 20 and the wing parts 13 of inner tube 10 are alternately placed in the circumferential direction. Namely, each of the wing parts 23 of outer tube 20 are positioned at the gap between adjacent blades 13 of inner tube 10, and each of the wh g parts 13 of inner tube 10 are positioned at the gap between adjacent wing parts 23 of outer tube 20. Further, the phrase "are alternately positioned in the circumferential direction" means that at least a part of the wing parts of outer tube 20 or inner tube 1 should be positioned so that it overlaps the gap between adjacent wing parts on the other end. The wing parts do not necessarily have to be positioned in the middle of adjacent wing parts on the other end. In addition, wing parts 13 and wing parts 23 are provided at mutually corresponding positions in the axial direction of fistula catheter I . The phase "are provided at corresponding positions in the axial direction" will herein mean that both wing parts 13 and wing parts 23 are provided at about the same positions in the axial direction of fistula catheter 1.

By pushing the distal end of inner tube 10 and the distal end of outer tube 20 in the state shown in

Fig. 6 - 8 so that they move together on the proximal side and bending belts 12 and belts 22 radially outward, wing parts 13 and wing parts 23 are formed, and curved parts 17 and curved parts 27 are provided. Afterwards, because intracorporeal fixed part B with the shape shown in Figs. 1-4 is formed, fistula catheter 1 is produced by heat forming it in this shape.

Inner tube 10 and outer tube 20 are formed by materials that have flexibility even after thermal formation. Therefore, by separating distal end 15 of inner tube 10 and distal end 25 of outer tube 20 from proximal end 14 and proximal end 24 in the axial direction, inner tube 10 and outer tube 20 reach an extended state in which they are extended approximately straight (see Fig. 6). And when this extended state is released, it again reaches the state in which wing parts 13 and wing parts 23 are formed as shown in Fig. 1.

Next the placement operation into fistula 73 will be described for a fistula catheter configured in this way. Fig. 9 is a view describing the insertion/removal operation of fistula catheter 1 according to embodiment 1, and Fig. 10 is a view describing the placed state of the same fistula catheter 1.

Extension tool 50 used for extending intracorporeal fixed part B of fistula catheter 1 and inserting this intracorporeal fixed part B into alimentary canal wall 7, which is gastric wall, intestinal wall, or the like, will now be described.

As shown in Fig. 9, extension tool 50 comprises tube engagement part 51 that is provided on the tip side, operating part 52 that is provided on the end opposite from tube engagement part 51 , and shaft part 53 mat is provided between operating part 52 and tube engagement part 51. Tube engagement part 1 and shaft part 53 are configured to be insertable into the lumen of inner tube 10. Operating part 52 is configured of a composite resin or metal, for example, and has a shape on which the practitioner can place a finger.

Tube engagement part 51 is configured so that it has a diameter that is the same size as the inner diameter of inner tube 10 or is slightly larger than the inside diameter of inner tube 10. The length of tube engagement part 1 in the axial direction is configured so that it is the length of proximal side fixed part 31, distal side fixed part 32, and intermediate part 33 in inner tube 10 combined or longer.

Tube engagement part 51 configured in this way is placed inside the lumen across proximal side fixed part 31 , distal end side fixed part 32, and intermediate part 33 of inner tube 10 in an extended state. Because projecting part 18 is provided in the vicinity of distal end 15 of inner tube 10, the tip part of extension tool 50 is locked by projecting part 18. When this happens, the outer surface of tube engagement part 51 and the inner surface of inner tube 10 are in close contact, and the extended state of inner tube 10 is maintained by the frictional force generated between the outer surface of tube engagement part 51 and the inner surface of inner tube 10.

Because outer tube 20 is fixed to inner tube 10 at proximal side fixed part 31 and distal side fixed part 32, outer tube 20 is also extended along with the extension of inner tube 10, and fistula catheter 1 reaches the state shown in Fig. 9.

Further, the configuration of extension tool 50 described herein is one example, but the shape thereof and the structure for extending fistula catheter 1 are not restricted by this.

For example, inner tube 10 may also be extended by using a rod-shaped member that can be inserted into the lumen of inner tube 10 as the extension tool and pushing projecting part 18 of inner tube 10 via the tip of the rod-shaped member inserted into the lu men of inner tube 10.

In addition, an example is illustrated that is provided with projecting part 18 in inner tube 10 as a structure for engaging the tip of the extension tool, but a ring-shaped member could also be furnished in the lumen on the distal side of inner tube 10 to engage the tip of the extension tool.

As shown in Fig. 9, fistula catheter 1, which is in a state that has been extended by extension tool 50, is inserted into fistula 72 formed in both abdominal wall 71 and alimentary canal wall 72. The diameter of fistula catheter 1 is the same as the diameter of outer tube 20 at its largest, so the resistance is low when it is passed through fistula 73. Thus, there is little risk of damaging fistula 73.

When an appropriate insertion depth has been reached, while pushing on the abdominal wall 71 side so catheter part A does not come out, the practitioner pulls on extension tool 50 on the near side. The state of close contact between tube engagement part 51 and the inner surface of inner tube 10 is released by pulling with a force that exceeds the frictional force between tube engagement part 51 and imier tube 10, and the extension tool 50 is pulled out from within inner tube 10. Because fistula catheter 1 is thermally formed, when the extended state is released by pulling out extension tool 50, it reaches the state in which intracorporeal fixed part B is formed as shown in Fig. 10. Fistula catheter 1 in an extended state can be changed into the state in which intracorporeal fixed part B is formed just by pulling out extension tool 50, so it is simple and easy.

The proximal end of catheter part A of a catheter placed in fistula 73 is located outside the body, and an extracorporeal fixed part is furnished on the proximal side of this catheter part A. For example, in a so-called button type, the extracorporeal fixed part is furnished on the proximal end of catheter part A, which is formed to a length at which there is almost no exposure on the side on the surface of the body. In addition, in a so-called tube type, the extracorporeal fixed part is detachably furnished in a section located near the surface of the body on catheter part A, which is formed so that it protrudes a fixed length on the side on the surface of the body.

When fistula catheter 1 is placed inside the alimentary canal wall and forms intracorporeal fixed part B as shown in Fig. 10, the upper surface of blades 13 and blades 23 (the surface on the proximal side) come into contact with the alimentary canal wall.

Because wing parts 13 of inner tube 10 and wing parts 23 of outer tube 20 are alternately disposed in the circumferential direction, the gap between each of the wing parts is reduced. In particular, a roughly circular surface S is formed, by wing parts 13 of inner tube 10 and wing parts 23 of outer tube 20 at the center part of wing parts 13 and wing parts 23 (i.e., near the outer surface of outer tube 20 and inner tube 10), as shown in Fig. 3. This surface S comes into contact with the perimeter of fistula 73 of alimentary canal wall 72. Because alimentary canal wall 72 is contacted by surface S, there is little invasion into alimentary canal wall 72.

In addition, because curved parts 17 and curved parts 27 are provided on wing parts 13 and wing parts 23, wing parts 13 and wing parts 23 take on a rounded shape against alimentary canal wall 72. Thus, a strike against the wall of the alimentary canal is softened, and invasion into the wall of al imentary canal 72 can be reduced.

In addition, when fistula catheter 1 is pulled from the abdominal wall 71 side, for example, the upper surface of wing parts 23 pushes against alimentary canal wall 72, and the force acts on wing parts 23 of outer tube 20 in a state of radial expansion in a direction that attempts to close it. Namely, as for the wing parts 23 of outer tube 20, it attempts to reduce the outside diameter of wing parts 23 by moving bent part 26 radially inward.

However, because wing parts 13 of inner tube 10 are put in between adj cent blades 23 of outer tube 20, wing parts 13 of inner tube 10 provide resistance when wing parts 23 of outer tube 20 attempt to close, and the attempted closure of wing parts 23 of outer be 20 can be inhibited. Namely, the fixed state due to intracorporeal fixed part B can be maintained, and the unintentional removal of fistula catheter 1, such as self-removal or the like, can be inhibited.

Further, when fistula catheter 1 in a placed state is removed from fistula 73, it is pulled out in a state in which the intracorporeal fixed part of fistula catheter 1 is extended by the same procedure as when it is inserted.

In this way, according to embodiment 1, because wing parts 13 of inner tube 10 and wing parts 23 of outer tube 20 are alternately disposed along the circumferential direction, the gap between wing parts 13 and wing parts 23 is reduced, and the contact area of the intracorporeal fixed part on the alimentary canal wall is increased, so invasion into the alimentary canal wall can be reduced. Therefore, the risk of ulcers in the alimentary canal wall or buried bumper syndrome can be reduced. In addition, because wing parts 13 of inner tube 10 and wing parts 23 of outer tube 20 are alternately disposed along the circumferential direction, a reduction in the size of the diameter of wing parts 13 and whig parts 23 can be hiliibited when fistula catheter 1 is pulled from outside the body while it is placed. Thus, it is difficult to release the fixed sate of intracorporeal fixed part B while it is within alimentary canal wall 72, and unintentional removal, such as self-removal or the like, can be inhibited.

In addition, fistula catheter 1 is configured by inserting inner tube 10 into outer tube 20, so its outer diameter is the outside diameter of outer tube 20 in an extended state. Thus, in comparison to bumpers, which are typically made of a synthetic resin, configured so that the diameter expands while inside the alimentary canal wall, the outer diameter is smaller when it is extended. Therefore, there is less resistance to the fistula during insertion/removal, and the risk of damaging fistula 72 can be reduced.

In addition, fistula catheter 1 is configured with two tubes, inner tube 10 and outer tube 20, so it has a small number of parts. Thus, an increase in the production costs can be inhibited.

hi addition, because fistula catheter easily takes on an extended state by pulling apart the distal side and the proximal side, the procedure during insertion/removal is easy, and the practitioner' s burden can be reduced.

In addition, the inner tube 10 is longer on the proximal side than outer tube 20 and is configured at a length at which proximal end 14 of imier tube 10 protrudes on the side on the surface of the body when it has been placed in fistula 73. Thus, even supposing inner tube 10 protruding to the side on the surface of the body is pulled, wing parts 23 of outer tube 20 inside the wall of the alimentary canal have a bigger diameter and become a retainer, and it is difficult for fistula catheter 1 to come out of fistula 72.

Embodiment 2.

Fig. 11 is a schematic view of the main parts of fistula catheter 1 according to embodiment 2. Fig. 12 is a sectional schematic view of the main parts of fistula catheter 1 according to embodiment 2, and the operation for extending intracorporeal fixed part B of fistula catheter 1 is shown. Further, for the sake of convenience in the description, the outer tube is not shown in Fig. 12. In addition, in embodiment 2 and the following embodiments, the description will focus on the points of difference from embodiment 1 , and the same numerals will be attached to the same or corresponding structures as in embodiment 1.

As shown in Fig. 1 1 and Fig. 12, fistula catheter 1 according to embodiment 2 is provided with inner cylinder 60 that is inserted into inner tube 10.

Inner cylinder 60 is composed of stainless steel, titanium, or the like, and it has a lumen for passing fluids through to the interior.

As shown in Fig. 1 1 and Fig. 12(a), inner cylinder 60 functions to maintain the shape of wing parts 13 of inner tube 10. Namely, fixated part 63 of inner cylinder 60 is fixated to the inner surface of the distal side of inner tube 10, and fixed part 64 of inner cylinder 60 is fixed to the inner surface on the more proximal side than beginning edge P of wing parts 13. hi this way, fixated part 63 and fixed part 64 allow the state of wing parts 13 formed by bringing the proximal end and distal end of inner tube 10 to be maintained. Additionally, the shape of wing parts 23 of outer tube 20 fixated to inner tube 10 is also maintained similar to inner tube 10.

Flanged tip diameter expansion part 62 in which the diameter expands outwards radially is fonned near the tip on the distal side of inner cylinder 60. Tip diameter expansion part 62 has a shape that gently contracts toward the tip, and it is configured so that it is difficult to damage the fistula or alimentary canal wall by tip diameter expansion part 62 during insertion/removal or

placed. Tip diameter expansion part 62 is disposed at a position where it protrudes from distal end 15 of inner tube 10.

The length of inner cylinder 60 in the axial direction is configured so that it is the length of proximal side fixed part 31 , distal side fixed part 32, and intermediate part 33 in an extended state all combined or longer.

Fixated part 63 is provided in an area more on the proximal side than tip diameter expansion part

62 on the outer surface of inner cylinder 60, and fixed part 64 is provided in the area of the proximal side of the outer surface of the distal end of inner cylinder 60. Further, fixated part 63 and fixed part 64 are drawn with a bold line in Fig. 11 and Fig. 12 for the purpose of description.

Fixated part 63 is fixated to the inner surface of inner tube 10. Fixated part 63 is fixated to the inner surface more on the distal side than the distal end of slits 11 of imier tube 10. In embodiment 2, an adhesive is used as a means of fixation to inner tube 10 at fixated part 63. Further, an arbitrary means can be used as a means of fixation to inner tube 10 at fixated part 63. For example, a protuberance formed on the imier surface of inner tube 10 could engage with a protuberance fonned on the outer surface of inner cylinder 60, or it could be fixated by a frictional force between the inner surface of inner tube 10 and a protuberance formed on the outer surface of inner cylinder 60.

Fixed part 64 is fixed to the inner surface of inner tube 10 so that it is moveable in the axial direction. Further, saying that it is fixed so that it is movable in the axial direction herein means that fixed part 64 is fixed at different positions on the inner surface of inner tube 1 by the state of inner tube 10, i.e., an extended state or a state after the extended state has been released (the state in which wing parts 13 are fonned). hi embodiment 2, the outside diameter of fixed part 64 is configured at the same size as the inside diameter of inner tube 10 or slightly larger, and fixed part 64 is fixed to the inner surface of inner tube 10 by the frictional force generated between fixed part 64 and the inner surface of inner tube 10.

In addition, tapered part 66 is configured to the outer circumference from proximal end 61 of inner cylinder 60 up to fixed part 64. Internal projection 65 that projects radially inward is provided on the inner surface of inner cylinder 60. Internal projection 65 functions to engage the tip of aforementioned extension tool 50.

Further, because internal projection 65 has the same function of projecting part 18 of inner tube 10 in embodiment I, inner tube 10 according to embodiment 2 is not provided with projecting part 18.

Next, the extension operation of fistula catheter 1 will be described by referring to Fig. 12(a) to

Fig. 12(c).

First, fistula catheter 1 will be in the state shown in Fig. 12(a) in which wing parts 13 are formed in inner tube 10 of fistula catheter 1. In this state, extension tool 50 is inserted into the lumen of inner tube 10 and inner cylinder 60. Here, extension tool 50 according to embodiment 2 has inner cylinder engagement part 54 detachably fixed to the inner surface of inner cylinder 60, and it is not provided with tube engagement part 51 shown in embodiment 1. Embodiment 2 has been configured so that by the frictional force generated between the inner surface of internal projection 65 provided in inner cylinder 60 and the outer surface of inner cylinder engagement part 54, the two are fixed to each other. Namely, when extension tool 50 it inserted up to an appropriate position inside inner cylinder 60, a frictional force acts between imier cylinder engagement part 54 and internal projection 65 of inner cylinder 60, and progress of extension tool 50 into inner cylinder 60 is interrupted.

hi this state, by pushing extension tool 50 further in, if a force is applied that exceeds the frictional force with the inner surface of inner tube 10 at fixed part 64, the fixture between the two is temporarily released. When this happens, inner cylinder 60 that has been engaged by inner cylinder engagement part 54 of extension tool 50 advances to the distal side along with extension tool 50. The tip of inner tube 10 fixated to this inner cylinder 60 by fixated part 63 also begins to advance to the distal side. By pushing in extension tool 50 in this way, wing parts 13 of inner tube 10 extend and reach a state like in Fig. 12(c). In order to implement this operation, the frictional force generated between inner cylinder engagement part 54 and internal projection 65 of inner cylinder 60 is configured so that it is bigger than the frictional force generated between fixed part 64 and the inner surface of inner tube 10. In addition, although it is not shown in Fig. 12, wing parts 23 of outer tube 20 similarly reach an extended state along with the extension of wing parts 13 of inner tube 10.

In this way, fistula catheter 1 reaches an extended state, and insertion into and removal from fistula 73 becomes possible.

In this way, according to embodiment 2, inner cylinder 60 is provided to be inserted into inner tube 10. This inner cylinder 60 is provided with fixed part 64 that is fixed to the inner surface of inner tube so that it is moveable in the axial direction on the more proximal side than the tip of the proximal side of slits 1 1 of inner tube 10, and fixated part 63 is provided that is fixated to the inner surface of inner tube 10 on the more distal side than the tip of the distal side of slits 11 of inner tube 10. In the state in which wing parts 13 and wing parts 23 have been formed, by fixing fixed part 64 and fixated part 63 to the inner surface of inner tube 10, the shape of wing parts 13 and wing parts 23 can be maintained. Thus, it gets easier to preserve the shape of intracorporeal fixed part B, even when it is inside alimentary canal wall 72, which is exposed to content and fluids with a violent action. Therefore, the placed state of fistula catheter 1 can be favorably preserved, and its unintentional removal, such as self-removal or the like, can be inhibited.

Further, the structure by which inner cylinder 60 and extension tool 50 are detachably fixed is not restricted to those structures utilizing the frictional force due to inner cylinder engagement part 54 and internal projection 65 described above. A structure could be used that is fixable between extension tool 50 and inner cylinder 60 when extension tool 50 is inserted that should extend wing parts 13 and wing parts 23 of fistula catheter and separates the two when extension tool 50 should release the extended state. For example, a screw that screws together the inner surface of inner cylinder 60 and the outer surface of extension tool 50 near the tip. Embodiment 3.

Embodiment 1 was configured with the inner tube longer than the outer tube, but in embodiment 3, a fistula catheter will be described that is configured so that the outer tube is longer than the inner tube.

Fig. 13 is a perspective view of fistula catheter 1A according to embodiment 3.

As shown in Fig. 13, the outer tube 20A is longer on the proximal side than inner tube 1 OA and is configured at a length at which proximal end 24 of outer tube 20A protrudes on the side on the surface of the body from the fistula when it has been placed in the fistula. Inner tube 10A which is configured shorter than outer tube 20A is in a state in which it has been inserted into outer tube 20A. Otherwise, the configuration is the same as embodiment 1.

In this way, the same effect as embodiment 1 can be achieved according to embodiment 3 even though outer tube 20A is longer than inner tube 1 OA.

In addition, outer tube 20A is longer on the proximal side than inner tube 10A and is configured at a length at which proximal end 24 of outer tube 20A protrudes on the side on the surface of the body from the fistula when it has been placed in the fistula. Therefore, only outer tube 20A becomes exposed on the upper side from intracorporeal fixed part B of fistula catheter 1. Thus, because there can be no bump due to the difference in the outer diameters of inner tube 10A and outer tube 20A, the resistance on the fistula during insertion/removal can be reduced. Therefore, the risk of damaging the fistula during insertion/removal can be reduced.

Further, besides the configurations described in embodiments 1 to 3 above, the following are also possible. In embodiment 1 , an example was illustrated in which curved parts 17 and curved parts 27 were provided on wing parts 13 and wing parts 23, respectively, but it could be configured without providing the curved parts, as shown in Fig. 14, for example.

hi addition, in embodiment 1, curved parts 17 and curved parts 27 were shown that curve toward the distal side in the axial direction, but curved parts with other shapes could also be provided. Namely, as shown in Fig. 15, for example, wing parts 13 (wing parts 23) are curved towards the proximal side in the axial direction. Further, bent part 16 (bent part 26) is curved so that it approaches the outer wall of inner tube 10 (outer tube 20). By curving wing parts 13 so that they form a U-shape when viewed from the side and forming curved parts 17 (curved parts 27), because the alimentary canal wall is contacted at the section where wing parts 13 (wing pails 23) are curved, a strike against the wall of the alimentary canal is softened, and invasion into the wall of the alimentary canal can be reduced.

In addition, in embodiment 1, an example was illustrated in which the inner surface of outer tube 20 and the outer surface of inner tube 10 are fixed to each other by a fixing means, such as an adhesive, at two places on proximal side fixed part 1 and distal side fixed part 32, but the fixing means is not restricted to an adhesive. For example, in addition to being provided with a protuberance on the outer surface of inner tube 10, an engagement opening is provided that engages the protuberance on the inner surface or wall section of outer tube 20, and the protuberance of inner tube 10 is inserted into engagement opening of outer tube 20. In this way, inner tube 10 and outer tube 20 can be fixed to each other.

In addition, as previously described, an example was illustrated in which the inner surface of outer tube 20 and the outer surface of inner tube 10 were fixed to each other at proximal side fixed part 31 and distal side fixed part 32. However, the inner surface of outer tube 20 and the outer surface of inner tube 10 do not necessarily need to be fixed at two places trapping wing parts 13 and wing parts 2 .

Namely, by providing wing parts 13 and wing parts 23 at corresponding positions in the axial direction, because these wing parts restrict the movement of outer tube 20 and inner tube 10 in the axial direction, an effect can be achieved that is equivalent to embodiment 1.

In the above description, the number of slits 1 1 and slits 21 was set to 3 each in inner tube 10 and outer tube 20, but it can be set to an arbitrary number of 2 or more slits. In addition, an example was illustrated in which slits 1 1 and slits 21 were provided at a position that trisected the peripheral wall of inner tube 10 or outer tube 20 in the radial direction, but they could be provided at positions that do not divide them equally in three. The length of slits 11 and slits 21 could be different in the axial direction. In addition, as described above, an example was illustrated in which slits 11 and slits 21 were provided in order to form belts 12 and belts 22 in inner tube 10 and outer tube 20. These slits fonn a thin gap in inner tube 1 0 and outer tube 20, but cuts could also be provided that are not these kinds of slits. The same material could be used for inner tube 10 and outer tube 20, or different materials could also be used. The thickness of inner tube 10 and the thickness of outer tube 20 could be the same thickness or a different thickness.

Table 1. Description of the Numerals

Claims

1. A fistula catheter comprising:

a catheter part and an intracorporeal fixed part, said intracorporeal fixed part being formed on the distal side of said catheter part and placed within the wall of the alimentary canal, said intracorporeal fixed part having an inner tube and an outer tube, said outer tube on the outside of said inner tube;

said inner tube and said outer tube being configured with belts formed by dividing the tube wall a plurality of times in the circumferential direction and having wing parts having sections extendable outwards radially;

and said wing parts of said inner tube and said wing parts of said outer tube being provided in corresponding positions in the axial direction and being alternately disposed along the circumferential direction.

2. The fistula catheter according to claim 1, wherein said wing parts of said outer tube and said inner tube are configured by bending or curving at least a part of said belts by moving the distal side and the proximal side of said belts towards each other in the axial direction.

3. The fistula catheter according to claim 1, wherein said outer tube and said inner tube are substantially straight upon extension so that the proximal end and the distal end separate from each other, and are defonnable so that sections extend outwards radially upon moving the distal end and proximal end towards each other.

4. The fistula catlieter according to claim 3, wherein said wing parts of said outer tube and said inner tube have curved parts that curve towards the distal side or the proximal side in the axial direction.

5. The fistula catheter according to claim 4, wherein said outer tube is longer on the proximal side than said inner tube and is configured at a length at which the proximal end of the outer tube protrudes on the side on the surface of the body when placed in the fistula.

6. The fistula catheter according to claim 1, wherein said wing parts of said outer tube and said inner tube have curved parts that curve towards the distal side or the proximal side in the axial direction.

7. The fistula catheter according to claim 6, wherein said inner tube is longer on the proximal side than said outer tube and is configured at a length at which the proximal end of the inner tube protrudes on the side on the surface of the body when placed in the fistula.

8. The fistula catheter according to claim 6, wherein said outer tube is longer on the proximal side than said inner tube and is configured at a length at which the proximal end of the outer tube protrudes on the side on the surface of the body when placed in the fistula.

9. The fistula catheter according to claim 8, further comprising:

an inner cylinder inside said inner tube, said inner cylinder having a fixed part that is movable in the axial direction to the inner surface of said inner tube at a position more on the proximal side than said wing parts of said inner tube; and

a fixated part fixated to the inner surface of said inner tube at a position more on the distal side than the end part of the distal side said slits or cuts in said inner tube.

10. The fistula catheter according to claim 1 , wherein said inner tube is longer on the proximal side than said outer tube and is configured at a length at which the proximal end of the inner tube protrudes on the side on the surface of the body when placed in the fistula.

11. The fistula catheter according to claim 10, further comprising:

12. The fistula catheter according to claim 1, further comprising: