WO2004056414A1

WO2004056414A1 - A workable catheter

Info

Publication number: WO2004056414A1
Application number: PCT/DK2003/000920
Authority: WO
Inventors: Pia Norup Nielsen; Allan Tanghoej
Original assignee: Coloplast A/S
Priority date: 2002-12-20
Filing date: 2003-12-19
Publication date: 2004-07-08
Also published as: AU2003287929A1

Abstract

The invention relates to a catheter for urinary catheterisation. More particularly, the invention relates to a catheter allowing a permanent or semi-permanent deformation of the catheter by hand prior to insertion. The catheter may e.g. comprise a deformable member such as a steel wire, which may be present in a cavity of the catheter. Accordingly the catheter may be bend, curved and otherwise shaped by the user to suit individual needs, allowing for easier manipulation and insertion of the catheter.

Description

A WORKABLE CATHETER

FIELD OF THE INVENTION

The present invention relates to a catheter for urinary catheterisation, e.g. for draining the bladder of a person. More particularly, the invention relates to a catheter allowing easier manipulation and insertion into a urinary canal of the user.

BACKGROUND OF THE INVENTION

A urinary catheter normally forms an oblong catheter tube with a conduit or a structure with a similar function for insertion into the urethra of an individual for draining the bladder. Some catheters are equipped with gripping means or similar arrangements supporting gripping of the catheter, thereby facilitating manipulation of the catheter during insertion and removal of the catheter from a urinary canal. Existing catheters may, however, be difficult to insert into the urinary canal, in particular for female users for whom the anatomy and position of the opening of the urethra complicates finding of the opening of the urethra and makes it difficult to orient the catheter tip for insertion of the catheter.

This problem increases with the length of the catheter and depends among other things upon the position and manoeuvrability of the user. In awkward positions, e.g. when the user is lying in a bed or sitting in a wheel chair, insertion of a regular catheter may be even more difficult.

From US 3,867,945 a catheter stiffener and former, having a proximal end being formed with an optimal curvature for the catheter to Vide over' obstructions in the urethra, is known.

Especially for users performing self-catheterisation a curvature of the catheter or a part of the catheter may help locating and orienting the catheter tip in the open- ing of the urethra. For that purpose the optimal curvature of the catheter or a part of the catheter is individual, depending e.g. on anatomy, position and dexterity of the user. Thus a pre-selected curvature of the catheter tip may not suit all users.

DESCRIPTION OF THE INVENTION

It is an object of a preferred embodiment of the present invention to provide a catheter which supports and facilitates insertion into the urethra. Accordingly, the present invention relates to a catheter forming at least one conduit for draining a bladder, said catheter comprises a proximal end to be inserted into the body and an opposite distal end, wherein at least a part of said catheter allows permanent or semi-permanent deformation of the catheter by hand prior to insertion. The catheter may allow the user to bend, fold, roll or in any similar way to shape the catheter by application of a pressure transverse to the length direction of the catheter, e.g. by finger pressure. The catheter may be reshaped while still at least partly enveloped in a package or after at least partially unpacking of the catheter.

Since the catheter allows permanent or semi-permanent deformation during use, it will not revert to its initial shape when releasing the grip. Accordingly, the user can bend a portion of the catheter into a shape which suits the individual user and which supports the manoeuvrability and helps the user to catch the opening of the urethra or similar natural or artificial urinary canal with the tip of the catheter. The catheter is thus workable and may be reshaped arbitrarily by the end- user during use, e.g. as a preparation for catheterisation, that could be performed immediately prior to catheterisation, or the catheter may even be reshaped during insertion. As explained reshaping of the catheter to suit individual needs is particularly useful for female users. In one embodiment of the invention the catheter is a female catheter adapted for insertion in the female urethra, i.e. it has a length in the range of 50-200mm, such as 130-180mm, such as a length in the size of 150mm or even as short as 50-90 mm, such as in the range of 55-85 mm, such as in the range of 60-80 mm, such as a length in the size of 70 mm. The deformation of the catheter may at least be semi-permanent, i.e. the catheter after de- formation reverts slowly towards its initial shape, such as for a catheter having elastic properties with a high relaxation time. The desired shape may thus be obtained at least for a time sufficient for the insertion of the tip of the catheter, such as at least for 15 seconds, such as at least for 30 seconds, such as for at least a minute or even for a few minutes or longer. The catheter may allow permanent deformation during use, i.e. prior to or during insertion of the catheter into the urinary canal. Thus, the catheter can be given a shape by applying an external force to the catheter and this shape will last until the shape is changed by the application of another external force to the catheter. The catheter may e.g. comprise a material allowing plastic deformation of the catheter.

In one embodiment of the invention the catheter maintains a substantial part of the deformation for at least the time necessary for the user to locate the opening of the urethra with the catheter tip and insert the catheter tip therein. This time may typically be at least 5 seconds, such as at least 10 seconds, such as at least 30 seconds, such as at least a minute depending e.g. on the dexterity of the user.

In one embodiment of the invention the catheter allows for a permanent or semipermanent deformation of the tip of the catheter i.e. a proximal end of the cathe- ter. This is especially advantageous for female users, who may then form the catheter tip to suit the individual angling of the urethra.

In one embodiment of the invention a major part of the catheter allows for a permanent or semi-permanent deformation. As an example for insertion of a rela- tively straight catheter in a female the whole catheter should preferably be angled according to the angling of the urethra, which may be awkward when sitting e.g. on a toilet. Thus it may be advantageous to curve a major part of the catheter, or even the entire catheter in order to facilitate insertion. In yet another embodiment of the invention a distal part of the catheter allows for a permanent or semi- permanent deformation. In this case the distal end of the catheter may e.g. be formed to provide a good handgrip during insertion. Preferably, the catheter is re-shapeable a multiple number of times, i.e. it allows the user to bend, fold, roll or in any similar way to shape the catheter by using the hands and/or the fingers.

In a preferred embodiment, the catheter may possess at least two states with respect to rigidity. In the first state, the catheter may allow permanent deformation, i.e. the catheter may possess a first rigidity so that, when the catheter is bend into a specific shape, the shape is maintained until further reshaping by application of an external force. In the second state, the catheter is more flexible, soft and com- pliant and no longer allows for substantial permanent deformation upon application of an external force. As soon as the external force is no longer applied, the catheter takes an arbitrary shape, e.g. it becomes straight or takes any shape depending e.g. upon the orientation and use of the catheter. In other words, in this second state the catheter may behave like a normal catheter made from a polymer material.

In one embodiment of the invention the catheter comprises a catheter element for draining urine and at least one deformable member, the deformable member extending longitudinally along at least a section of the catheter element. The de- formable member should more easily than the catheter element aquire a permanent or semi-permanent deformation by finger pressure.

The deformable member may comprise a deformable material, i.e. a material allowing permanent or semi-permanent deformation. The deformable member could be solid or hollow. In one embodiment of the invention the deformable member is arranged in a cavity of the catheter element. As an example the deformable member could be embedded in the catheter element or it could be present in a cavity in the catheter element. The catheter element may thus encircle at least a part of the deformable member.

As an example, the deformable member could be a solid member, such as a wire made from a soft and thus easily shapeable metal, such as copper or tin. The deformable member may be attached to the catheter element, e.g. adhesively. When attaching the deformable member, a glue could be used that is dissolved by contact with urine or the humid, warm conditions in the urethra. The deformable member could also be embedded in the catheter element during moulding or extrusion of the catheter. By adjusting the thickness of the wire in accordance with the rigidity of the catheter element, the wire may be able to maintain its shape permanently. Accordingly, the entire catheter maintains its shape permanently. Other metals, or metal alloys, which can be given a permanent shape, may likewise be used. Furthermore, any polymer and composite material, which can be given a permanent or semi-permanent shape, may be used to form the deformable solid member. The catheter element is typically made from a polymer allowing elastic deformation and it is typically provided in a straight shape. Thus, a catheter which can maintain its shape semi-permanently may be obtained by providing the deformable member in materials and dimensions such that the catheter is deformable but so that it will revert slowly to its former shape, e.g. straighten due to the elasticity of the catheter element. Due to the elasticity of the catheter element and in some cases even some elasticity of the deformable member, some 'over-shaping' of the catheter may be necessary to obtain the desired shape after a short relaxation of the order of a second.

Reshaping of the catheter is mainly advantageous in order to facilitate the insertion of the catheter into the urinary canal. Once the catheter tip has caught the opening of the urinary canal, flexibility of the catheter in order to allow the catheter to follow the urinary canal is typically desirable in order to avoid damage of the mucosal lining. Accordingly, at least a part of the catheter may be inserted in a state allowing permanent deformation, but be further inserted and removed in a state wherein at least a part of the catheter is soft and compliant.

In one embodiment of the invention the deformable member can be removed from the cavity prior to, or during, insertion or removal of the catheter from a urinary canal. Typically, the deformable member is removable from the cavity at least during insertion. The catheter element may comprise a cavity into which a deformable solid member can be inserted. By further providing the deformable member with a gripping means, preferably in the distal end, the deformable member may be extracted from the catheter element, thereby changing the rigidity of a part of the catheter, which no longer comprises the deformable member. During use, the user shapes the catheter for easy insertion into the urinary canal. Once the tip of the catheter enters the opening of the urinary canal, the deformable member is removed from the cavity. The removal may occur during simultaneous insertion of the catheter into the urinary canal until the urine starts to drain.

In one embodiment, the catheter is made entirely or partly from a shape memory polymer material. As an example, a solid member made from a shape memory polymer may be embedded in or attached to a standard polymer catheter element.

In one embodiment of the invention, the deformable member is made from a material, the molecular structure of which is changed upon deformation.

The shapeability of the catheter may depend on the temperature of the catheter. As an example, the catheter may comprise or even be made entirely from a ma- terial which changes its properties due to a change in temperature. Since the urinary canal typically posses a higher temperature than that of the surroundings, the change in temperature could be caused by the insertion of the catheter into the urinary canal. As an example, the catheter may comprise a deformable material comprising a substance, which enters liquid phase at a temperature in the range of 20-37 °C. The deformable member may comprise a substance comprising fatty acids. The substance may also comprise a shape memory polymer or similar material with a melting point between 20 °C and 37 °C. Below 20 °C, or below a specific temperature around room temperature, e.g. below 18°C, 19°C, 21 °C or 22°C, the substance is solidified and allows permanent deformation. At a temperature above room temperature, but below body temperature, the substance enters liquid phase, and the catheter thereby becomes soft and compliant. Again, this may be advantageous in order to impose a specific shape to the catheter prior to, or during use. Once the catheter is in place in the urinary canal, the catheter changes rigidity so that easy removal of the catheter is facilitated. The aforementioned cavity may be made in such a way that the cavity is in communication with the conduit, or the cavity may form a part of the conduit. Espe- cially, the cavity and the conduit may be merged into one compartment. This will allow the substance to drain out of the catheter together with urine or similar drained substances as soon as it enters liquid phase.

According to a specific embodiment, the original shape or a specific pre- determined shape may be restored upon a raise in temperature of the catheter. Shape memory polymers typically posses this quality. The original shape or predetermined shape may also be restored upon a raise in humidity as encountered in the urethra. The catheter may e.g. have parts, e.g. a coating or longitudinal sections adapted to swell due to increased humidity, thereby straightening the catheter.

The deformable member could be oblong. The deformable member could extend over a certain part of the catheter, or it could extend over the entire length of the catheter from the proximal end to the distal end thereof. However, a configuration where two or more deformable members are inserted along the length of the cavity may also be used. Preferably, a deformable member is positioned at least in the proximal end of the catheter so that at least the proximal end of the catheter is permanently deformable. However, in order to allow the user to remove the deformable member and thus to increase the flexibility of the catheter during or after insertion into the urinary canal, a deformable member which completely co- extends the catheter from the proximal end to the distal end may be provided with gripping means arranged in the vicinity of the distal end of the catheter. Such gripping means can be formed as radially outwardly extending bulges or flanges or in any similar way to enhance the ergonomically correct handling for the re- moval of the deformable member from the catheter. The deformable member may be formed so that it makes up at least one conduit for draining the bladder therethrough. If the deformable member is not supposed to be removed from the catheter, the deformable member may be embedded in the catheter element, e.g. during fabrication of the catheter element or it may be attached adhesively to the catheter element. The deformable member may also be present in a cavity, said cavity after removal of the deformable member forming a conduit for draining urine.

In the previous description, a standard catheter imposed with a structure or means allowing permanent deformation has been assumed, however, the conduit or conduits formed by the catheter may be formed exteriorly between a urinary canal of a catheter user and the catheter. Thus, the urine may flow along grooves formed in the exterior surface of the catheter. Such a catheter may be solid and it may be adapted to comply with all of the aforementioned embodiments.

According to a second aspect, the invention provides a method of inserting a catheter into a human, the method comprising the steps of providing a catheter allowing at least semi-permanent deformation by hand, reshaping the catheter and inserting at least the catheter tip in the urethra. The method may further com- prise the step of providing for the catheter to change from a first state wherein the catheter possesses a first rigidity allowing said deformation and into a second state wherein the catheter possesses a second rigidity not allowing permanent deformation. This method could be performed using a catheter of the aforementioned kind, and with any of the mentioned features.

DETAILED DESCRIPTION OF THE INVENTION

Preferred embodiments of the invention will now be described in details with reference to the drawings in which:

Fig. 1 shows a non-deformed catheter and four examples of deformations of the catheter. Fig. 2 shows a catheter with an internal conduit, where the catheter comprises a deformable member.

Fig. 3 shows cross-sections of catheters comprising deformable members of various shapes and placements.

Fig. 4 shows a catheter with an external conduit, where the catheter comprises a deformable member. Furthermore, cross-sections of different configurations of the catheter with respect to the shapes and placement of the deformable member are shown.

Fig. 1 shows a drawing of a catheter according to the present invention. The catheter comprises a proximal end 1 to be inserted into the urinary canal, includ- ing inlets 4 to drain urine from the bladder into an internal conduit of the catheter. The catheter further comprises a middle piece 2 and a distal end 3. In the distal end, the urine drains out of the opening 5 provided in the connector part 6 of the catheter. The connector part allows connection of the catheter to a catheter extension tube, a drainage bag or similar arrangement. Fig. 1 illustrates three dif- ferent permanent shapes of a catheter according to the present invention. As a starting point in Fig. 1a, the catheter is straight. In Fig. 1b, the catheter is deformed into a first deformation where two bends 7 and 8 are introduced. In Fig. 1c, the catheter is deformed into a second deformation wherein two further bends 9 and 10 are introduced. With this shape of the catheter, even if the catheter is provided with a slippery surface, a person with reduced dexterity will much more easily be able to manipulate the catheter. Another shape of the catheter could be provided by bending the catheter into a relatively uniform curve with a larger radius as shown in Fig 1e. This shape could appear e.g. by bending the catheter prior to unpacking, e.g. over the leg of the user. Fig. 1d shows a catheter shaped with a curved tip. Fig. 2 shows a catheter similar to the catheter of Fig. 1. The permanent deformation is enabled via the insertion of a permanently deformable member 20 into a cavity 21 of the catheter. The member 20 is made of an easily deformable, but not very flexible, steel wire or string, which, upon deformation, stays in the de- formed shape. Such wires are known in the art. The wire can advantageously be inserted into a plastic hose during blow-moulding of the hose, the hose subsequently to be used for manufacturing of the catheter by regular catheter manufacturing processes including making of the catheter tip inlets 4 and the connector part 6

In Fig. 3 different placements and shapes of the deformable member in relation to a catheter with an internal conduit is shown. In Fig. 3a, an overview drawing including a deformable member 20 is provided. The cross-sectional plane AA indicated in Fig 2., refers to the cross-sectional views of Figs. 3 a-f. In Fig. 3a, the urine can flow in an internal cylindrical conduit 24 between an outer surface 22 and an inner surface 23. In this case an oblong substantially cylindrical deformable solid member is placed in a cavity formed in the wall of the tubular catheter body, i.e. in the area between the outer surface 22 and the inner surface 23 of the catheter. The deformable member is made of e.g. steel, copper or a similar metal, or from a deformable polymer or even from a deformable material comprising a substance, which enters liquid phase at a temperature in the range of 20-37 °C. In Fig. 3b, the catheter material surrounding the deformable member has been increased compared with the catheter of Fig. 3a so that the symmetrically cross-section of the conduit, changes to an unsymmetrical cross-section. In Fig. 3c, the deformable member has been attached to the inner surface of the catheter. In Fig. 3d) the deformable member is a tubular member running along the inner surface of the catheter. In Fig. 3e, an elongated sheet, or girder, is used as an unsymmetrical deformable member. The purpose of introducing an unsymmetrical deformable member is that the member only can be deformed in a cer- tain direction. Accordingly, it is possible to deform the catheter in a controlled direction, e.g. a certain direction in relation to the inlets 4, whereas, deformation in other directions is inhibited by the shape of the member. In Fig. 3f, a second sheet, or girder, has been introduced. The two sheets form a T-profile and therefore, the catheter does not support deformation in any directions. By allowing the removal of either one, or both, of the sheets, the catheter may change characteristics to allow deformation in one or more different directions. In Fig. 3g the de- 5 formable member fill up the entire conduit. In this embodiment the deformable may also function like a plug to control drainage e.g. when the deformable member is removed after completing insertion of the catheter.

Fig. 4 shows a urinary catheter of the kind wherein the urine is drained along the 10 outer surface of an oblong catheter body, i.e. between the outer wall of the catheter and inner wall of the urinary canal of the individual. This catheter may be made from a material which allows permanent deformation, or the catheter may comprise a deformable member, e.g. inserted into the oblong catheter body. In Fig. 4, different shapes of a deformable member inserted into the catheter body 15 32 is shown in a cross-sectional view. In Fig. 4b, a substantially cylindrical deformable member is placed in the central part of the catheter core, whereas in Fig. 4c and in Fig. 4d, the configurations with one and two sheets of deformable materials correspond to the configurations in Fig. 3e and in Fig. 3f.

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Claims

1. A catheter forming at least one conduit for draining a bladder, said catheter comprises a proximal end to be inserted into the body and an opposite distal end, wherein at least a part of said catheter allows a permanent or semi-permanent deformation of the catheter by hand prior to insertion.

2. A catheter according to claim 1 , wherein the catheter is a female catheter.

3. A catheter according to claims 1 or 2, wherein the catheter maintains a substantial part of the deformation for at least the time necessary for the user to locate the opening of the urethra with the catheter tip and insert the catheter tip therein.

4. A catheter according to any of the preceding claims, wherein a major part of the catheter allows said deformation of the catheter.

5. A catheter according to any of the preceding claims, adapted to change from a first state wherein the catheter possesses a first rigidity allowing said deformation and into a second state wherein the catheter possesses a second rigidity not allowing permanent deformation.

6. A catheter according to any of the preceding claims, said catheter comprising a catheter element for draining urine and at least one deformable member, wherein said deformable member extends longitudinally along at least a section of the catheter element.

7. A catheter according to claim 6, wherein the deformable member is arranged in a cavity of the catheter element.

8. A catheter according to claim 6 or 7, wherein the catheter comprises at least one deformable solid member.

9. A catheter according to any of the claims 7-8, wherein the deformable member 5 is releasably arranged in the cavity to allow removal therefrom during use.

10. A catheter according to any of claims 5-9, comprising a section made from a material wherein a change in the modulus of elasticity causes the changing between the first and second rigidity.

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11. A catheter according to any of the preceding claims, wherein said catheter is made from a shape memory polymer material.

12. A catheter according to any of the claims 7-11 , wherein the deformable mate- 15 rial comprises a substance which enters liquid phase at a temperature in the range of 20-37 degrees Celsius.

13. A catheter according to any of the preceding claims, wherein the original shape of the catheter is essentially restored upon a raise in temperature of the

20 catheter.

14. A catheter according to any of the claims 7-13, wherein the cavity is in communication with the conduit.

25 15. A catheter according to any of the claims 7-14, wherein the cavity forms a part of the conduit.

16. A catheter according to claim 6-15, wherein the deformable member co- extends the catheter element from the proximal end to the distal end of said 30 catheter element.

17. A catheter according to any of claims 6-16, wherein the deformable member extends beyond the distal end of the catheter and comprises gripping means arranged in the vicinity of the distal end of the deformable member.

5 18. A catheter according to any of claims 6-17, wherein at least one conduit is formed exteriorly as a groove in an outer surface of the catheter element, so as during use to form a conduit between a urinary canal of a catheter user and the catheter element.

10 19. A catheter according to any of claims 6-18, wherein at least one conduit extends interiorly in the catheter element.

20. A method of inserting a catheter into a human comprising the steps of

- providing a catheter allowing at least semi-permanent deformation by hand, 15 - reshaping the catheter.

- inserting at least the catheter tip in the urethra.

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