WO2024062218A1

WO2024062218A1 - A catheter

Info

Publication number: WO2024062218A1
Application number: PCT/GB2023/052402
Authority: WO
Inventors: Gavin Roberts; Nicola PILMER
Original assignee: Convatec Limited
Priority date: 2022-09-20
Filing date: 2023-09-18
Publication date: 2024-03-28

Abstract

Disclosed is a catheter comprising: an elongate main body having an insertion end for insertion into a urethra and an outlet portion at an outlet end. The outlet portion has an inner cavity through which fluid may flow from the catheter and a plurality of external sidewalls. At least one of the plurality of external sidewalls is planar. The catheter may have an external flushing portion comprising one or more open flow channels formed in an external surface of the main body. The one or more external flow channels may be in fluid communication with the inner cavity of the outlet portion via corresponding drainage apertures. The catheter may be configured in use to be inserted into the urethra until the one or more external flow channels are in fluid communication with the bladder so that urine can flow from the bladder along the one or more external flow channels and out from the catheter via the inner cavity of the outlet portion.

Description

A Catheter

Technical Field of the Invention

The present invention provides a urinary catheter which is configured to aid flushing of the urethra in use.

Background to the Invention

Urinary catheters for draining urine from the bladder may be indwelling or intermittent and are used to drain urine from a bladder. Intermittent catheters are typically used by patkients suffering from urinary incontinence or by disabled individuals several times a day to drain the bladder as required.

It is relatively common for users of intermittent catheters to develop urinary tract infections or other complications. In some cases, this is because intermittent catheters typically comprise a closed lumen which expels urine from the bladder without it contacting the urethra wall. As such there can be a persistent build-up of bacteria and debris (e.g., skins cells or excretions) which would otherwise be flushed out by the urine.

WO2012/85124 describes an intermittent urinary catheter comprising an elongate shaft with an insertion end, a handle connected to the elongate shaft at a distance from the insertion end, and a discharge end extending past the handle in a direction opposite the insertion end. The elongate shaft is provided with at least one discharge channel having an elongate opening extending along the elongate shaft. The discharge channel includes an opening against which a flow of urine can contact the urethra in use to aid with flushing of the urethra.

CN210992518U describes an indwelling catheter capable of flushing a urethra. The catheter includes a plurality of grooves formed along the length direction, and a plurality of small holes are formed at the bottom of each groove at intervals. During use, secretions in the urethra of a patkient enter the grooves and are discharged.

US 10668249 describes an intermittent catheter having a distal portion, a proximal portion, and a plurality of drainage eyes disposed at a junction between the distal portion and the proximal portion. The distal portion includes a tip, a plurality of elongated ribs, and a plurality of external flow paths. The proximal portion includes an internal lumen and a proximal end. The plurality of drainage eyes communicate with the plurality of external flow paths and the internal lumen. The present invention seeks to provide an improved catheter for flushing urethra in use.

Summary of the Invention

The present invention provides a catheter according to the appended claims.

The present disclosure provides, in a first aspect, a catheter comprising: an elongate main body having an insertion end for insertion into a urethra and an outlet end. The outlet portion may comprise an inner cavity through which fluid may flow from the catheter. The outlet portion may comprise a plurality of external sidewalls. At least one, and preferably at least two of the plurality of external sidewalls may be planar.

Providing an outlet portion with planar external sidewalls facilitates handling of the outlet portion during insertion, removal, and directing the stream of urine in use. This may be particularly advantageous for disabled users with reduced dexterity. An outlet portion with planar external sidewalls also facilitates the manufacture of the catheter by providing a flat surface on which to position the split line where the injection mould tool closes during moulding and opens for ejection of the part.

Accordingly, one embodiment of the invention provides a catheter comprising: an elongate main body having an insertion end for insertion into a urethra and an outlet portion at an outlet end, the outlet portion comprising an inner cavity through which fluid may flow from the catheter and a plurality of external sidewalls, wherein at least one of the plurality of external sidewalls is planar.

The outlet portion may comprise four planar external sidewalls. At least two planar external sidewalls may be parallel. At least two planar external sidewalls may be perpendicular. An interface between two adjacent planar external sidewalls may be curved. The interface may be a rounded transition between two adjacent, perpendicular planar sidewalls. The rounded transition may extend fully along the length of the outlet portion. There may be a rounded transition between each pair of adjacent planar sidewalls.

The plurality of planar external sidewalls may extend fully along the length of the outlet portion. There may be two pairs of planar external sidewalls. Each planar external sidewall of one pair may be perpendicular to each planar external sidewall of the other pair. The planar external sidewalls may be substantially flat. The planar external sidewalls may be substantially smooth. The external surface of the outlet portion may be substantially smooth.

The distal end of the outlet portion may comprise a lower face. The lower face may be planar. The lower face may be provided perpendicularly to at least one of the plurality of planar side walls. The lower face may comprise an outlet aperture formed therethrough. The inner cavity may terminate at the outlet aperture of the lower face. In this way, the inner cavity is open at the distal end of the cavity allowing exit of urine therefrom.

The cross-section of the outlet portion in the transverse direction may be rectangular, for example oblong. The outlet portion may be between 5mm and 10mm wide, preferably 7.5 mm. The outlet portion may be between 5mm and 10mm deep, preferably 6 mm. The outlet portion may be wider than it is deep. The outlet portion may have the same dimension as the external flushing portion in at least one direction. The outlet portion may have a greater dimension than the external flushing portion in at least one direction. Part of the outlet portion may be longer than another part of the outlet portion. The cross-sectional area of the outlet portion may be greater than the external flushing portion in the transverse direction. The outer perimeter of a crosssection of the outlet portion in the transverse direction may be between 20 mm and 45 mm. The outlet portion may be between 30mm and 50mm long, preferably 40 mm. Where there are four planar external sidewalls, two of the four planar external sidewalls may be longer than the other two planar external sidewalls.

The catheter may further comprise an external flushing portion extending between the insertion end and the outlet portion. The external flushing portion may define a fluid flow path from the insertion end to the outlet portion which is open to the exterior of the elongate main body. The external flushing portion may comprise an external flow channel on an external surface of the main body. The external flushing portion may have a solid central core. The external flushing portion may have a uniform cross-sectional area in the transverse direction along the length thereof. The part of the external flushing portion comprising the external flow channel may have a solid cross-section. The part of the external flushing portion comprising the external flow channel may be entirely solid. Accordingly in one embodiment there is provided a catheter comprising: an elongate main body having an insertion end for insertion into a urethra and an outlet portion at an outlet end, the outlet portion comprising an inner cavity through which fluid may flow from the catheter and a plurality of external sidewalls, wherein at least one of the plurality of external sidewalls is planar; and wherein the catheter further comprises an external flushing portion between the insertion end and the outlet portion.

In another embodiment there is provided a catheter comprising: an elongate main body having an insertion end for insertion into a urethra and an outlet portion at an outlet end, the outlet portion comprising an inner cavity through which fluid may flow from the catheter and a plurality of external sidewalls, wherein at least one of the plurality of external sidewalls is planar; and wherein the catheter further comprises an external flushing portion between the insertion end and the outlet portion; the external flushing portion comprising an external flow channel, wherein the external flow channel is in fluid communication with the inner cavity via a corresponding drainage aperture formed at a junction between the external flushing portion and the outlet portion.

Providing an external flow channel on an external surface of the catheter allows a flow of urine to contact the urethra during use. The flow of urine may act to flush the urethra and help reduce the possibility of infection.

The external flow channel may be in fluid communication with the inner cavity via a corresponding drainage aperture formed at a junction between the external flushing portion and the outlet portion. The outlet portion may be shaped at the junction to guide liquid from the external flow channel toward the corresponding drainage aperture. The outlet portion may be angled at the junction to guide liquid from the external flow channel toward the drainage aperture. The outlet portion may be shaped at the junction to collect liquid flowing along the external flow channel.

The number of external flow channels may be any suitable number for providing a described flow contact area and length. The catheter may comprise between one and six external flow channels. The catheter may comprise between two and five external flow channels. There may be a plurality of external flow channels and a plurality of corresponding drainage apertures. There may be two external flow channels and two corresponding drainage apertures. There may be an equal number of external flow channels and drainage apertures.

Each external flow channel may comprise a straight and/or helical portion. Each external flow channel may be aligned with a corresponding drainage aperture. Each external flow channel may terminate at a corresponding drainage aperture. Each external flow channel may be aligned with an adjacent planar external sidewall. The corresponding drainage aperture may extend from the external flow channel to the corresponding aligned planar external sidewall. Where there is a plurality of planar external sidewalls, the aligned planar external sidewall may have the shortest or equal shortest width of the plurality of planar external sidewalls.

The shape of a base portion of each external flow channel may be the same as the shape of a base portion of the corresponding drainage aperture. Each drainage aperture may extend axially and/or radially. The respective bases of the external flow channels and drainage apertures may have the same profile. The external flow channels may extend along the entire length of the external flushing portion.

The insertion end may have an insertion portion to facilitate insertion of the catheter into and along the urethra. The insertion portion may be solid. The insertion portion may comprise a solid wall. The insertion portion may define an inner lumen in fluid communication with the or each external flow channel. The insertion portion may comprise one or more eyelets formed in an external surface thereof and extending through to the inner lumen of the insertion portion. The insertion portion may comprise two eyelets arranged on opposite sides respectively of the insertion portion. At least two eyelets may be longitudinally offset.

The external flushing portion may comprise one or more walls each having an external surface arranged, in use, to contact the urethra wall and support the urethra in an open state. The, or each, wall may define the, or each, external flow channel. The, or each, wall may extend longitudinally. The, or each, wall may be straight or helical. The pitch of a helical wall may be constant. The, or each, wall may comprise a longitudinal axis. The cross-section of the, or each, wall transverse to the longitudinal axis of the main body may comprise a rounded profile. The rounded profile may comprise one or more radiuses of curvature. The, or each, wall may extend radially from a central axis of the main body. The, or each, radially extending wall may comprise an outermost surface and respective opposing side walls. The area of the outermost surface of the wall or the combined area of the outermost surfaces may be greater than the area of the open face of the, or the combined area of each, external flow channel.

The, or each, external flow channel may provide a fluid flow path to the outlet portion. The, or each, external flow channel may extend fully to the outlet portion. The, or each, external flow channel may extend continuously along the main body from the insertion end to the outlet portion.

The main body of the catheter may comprise an elongate member. The main body may be straight (i.e., in the absence of bending forces, at rest, the main body may be substantially straight). The main body may be rigid (i.e., substantially rigid, for example greater than a shore hardness of A80) thereby aiding insertion and maintaining the shape of the external flow channels in use.

The radially outermost surface of the, or each, wall may define an outside diameter of the external flushing portion. The outside diameter may be constant along the external flushing portion and insertion portion of the catheter. Hence, the overall width of the external flushing portion and insertion portion of the catheter may be constant along the length thereof. The cross-sectional area of the, or each, flow channel may be constant along the length of the external flushing portion. The combined area of the outer surface of the walls may be greater than the combined area of the open faces of the external flow channels. Alternatively, the combined area of the open faces of the external flow channels may be greater than the combined area of the outer surface of the walls. Preferably, the outer flow surface area created by the external flow channels is equal to or greater than the surface area of the inner lumen of the equivalent conventional catheter (i.e., a catheter comprising a tube defining an inner lumen along the length thereof for the outflow of urine) of the corresponding CH size.

The catheter may be formed as a singular piece. Alternatively, the catheter may be formed from separate component pieces that are attached together.

The shape and configuration of the outlet portion may obviate the need for a separate funnel attachment. For example, the outlet portion may be shaped and configured to have a square or an oblong cross-section in the transverse direction to facilitate handling and positioning of the outlet portion for the outflow of urine. Alternatively, a conventional funnel having a cylindrical cross-section may be attached to the outlet portion and forced to stretch to conform to the shape of the oblong outlet portion and thereby encourage a tighter, more secure fit.

The catheter may be a male urinary catheter or a female urinary catheter. The catheter may be a permanent or intermittent catheter. In a preferred embodiment, the catheter is an intermittent urinary catheter, and preferably an intermittent female urinary catheter.

Accordingly in embodiments there is provided a catheter comprising: an elongate main body having an insertion end for insertion into a urethra and an outlet portion at an outlet end, the outlet portion comprising an inner cavity through which fluid may flow from the catheter and a plurality of sidewalls, wherein at least one of the plurality of external sidewalls is planar; and wherein the catheter is an intermittent urinary catheter.

For a female catheter, the length of the catheter may be between 150 mm and 180 mm, preferably 160 mm. The length of the external flushing portion may be between 125 mm and 175 mm, preferably 145 mm.

For a male catheter, the length of the catheter may be between 360 mm and 425 mm, preferably 405 mm. The length of the external flushing portion may be between 300 mm and 350 mm, preferably 325 mm.

The diameter of the insertion portion and the external flushing portion may be between 2 mm and 6 mm depending on the size requirements of the intended user.

The pitch of the helical external flow channels may be between 15 mm and 40 mm, preferably 30 mm.

The depth of the external flow channels may be between 0.5mm and 2mm, preferably 1mm.

The present disclosure provides, in a second aspect, a method of manufacturing a catheter according to any aspect described herein by extrusion and/or injection moulding and/or 3D printing. The method may comprise manufacturing the catheter from multiple separate parts. For example, the catheter may comprise two parts, each formed by injection moulding and welded together e.g., by heat welding. In a preferred embodiment, the present disclosure provides a method of manufacturing a catheter according to any aspect described herein by injection moulding. The method may comprise the step of positioning the split line of the injection moulding tool on a planar surface of the catheter.

The present disclosure provides, in a third aspect, a method of catheterization using a catheter according to any aspect described herein. The method may comprise the steps of: (i) providing a catheter comprising an insertion end, an external flushing portion and an outlet portion, the external flushing portion comprising an open-faced external flow channel extending from the insertion end to the outlet portion, the outlet portion comprising a drainage aperture extending to an internal cavity for the outflow of fluid from the catheter, wherein the external flow channel is in fluid communication with the internal cavity of the outlet portion via the drainage aperture, and (ii) inserting the catheter into the bladder via the urethra until the external flow channel is in fluid communication with the bladder so that urine can drain from the bladder through the urethra along the external flow channel of the catheter. The outlet portion may be arranged at the base of the urethra to collect urine flowing along the external flow channel and direct the urine into the internal cavity via the drainage aperture. The method may comprise grasping the catheter using the planar external sidewalls.

The skilled person will appreciate that except where mutually exclusive, a feature described in relation to any one of the aspects, embodiments or examples described herein may be applied to any other aspect, embodiment, or example. Furthermore, except where mutually exclusive, any feature described herein may be applied to any aspect and/or combined with any other feature described herein. Brief Description of the Drawings

In order that the invention may be more clearly understood one or more embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings, of which:

Figure 1 shows a perspective view from the proximal end of a schematic representation of a catheter according to the present disclosure;

Figure 2 shows an alternative perspective view of the catheter of Figure 1;

Figure 3 shows a first side view of the catheter of Figure 1; Figure 4 shows a second side view of the catheter of Figure 1, the second side view circumferentially offset by 90 degrees from the first side view;

Figure 5 shows a cross section of the catheter of Figure 1 from the first side view;

Figure 6 shows an enlarged perspective view of a junction between the external flushing portion and the outlet portion of the catheter of Figure 1;

Figure 7 shows an alternative enlarged perspective view of the outlet portion at the junction with the external flushing portion of the catheter shown in Figure 1;

Figure 8 shows an enlarged underside view of the outlet portion of the catheter of Figure 1 ; and

Figure 9 shows an enlarged perspective view of a schematic representation of the insertion portion and part of the external flushing portion of an alternative embodiment of a catheter according to the present disclosure.

Detailed Description of the Invention

In the following detailed description, numerous specific details are set forth to provide a thorough understanding of various embodiments and the inventive concept. However, those skilled in the art will understand that the present invention may be practiced without these specific details or with known equivalents of these specific details, that the present invention is not limited to the described embodiments, and that the present invention may be practiced in a variety of alternative embodiments. It will also be appreciated that well known methods, procedures, components, and systems may have not been described in detail.

In the following description, reference to longitudinal should be taken to be in relation to the longitudinal axis of the catheter, unless otherwise stated. Reference to the “transverse cross-section”, or simply “cross-section”, should be taken to be the cross-section which is transverse to the longitudinal axis of the main body, unless otherwise stated. References to distal and proximal made herein should be taken to be in relation to the insertion end of the catheter.

The catheters described herein are primarily intermittent female urinary catheters. However, it will be appreciated that the inventive concepts and features described herein may be applied to indwelling urinary catheters and may be applied to male or female catheters whether intermittent or indwelling. Figures 1 and 2 show a urinary catheter 1 comprising an elongate main body 3 having an insertion end 5 for insertion of the catheter 1 into a urethra and an outlet end 7 having an exit from which fluid exits the catheter 1. The insertion end 5 comprises an insertion portion 9 for urging the catheter 1 along the urethra and into the bladder, and the outlet end 7 comprises an outlet portion 11 for the outflow of fluid, e.g., urine, from the catheter 1 via the exit.

The main body 3 comprises an external flushing portion 13 extending between the insertion portion 9 and the outlet portion 11. The external flushing portion 13 comprises a plurality of external flow channels 15 which provide a fluid flow path. The external flow channels 15 are provided in the external surface of the main body 3, are elongate and open faced in the radial direction so that, when inserted, the catheter 1 mates with the urethral wall (not shown) to enclose the flow channels 15. Hence, when inserted, the urethral wall is exposed to a flow of urine flowing along the external flow channels 15 of the external flushing portion 13.

The external flow channels 15 are separated by walls 17 extending longitudinally, thereby forming substantially straight walls 17 that are parallel with the longitudinal axis 19. The size and number of external flow channels 15 may vary according to the application and desired characteristics of the catheter 1. Typically, the size and number of the external flow channels 15 may be varied to alter the flow rate, velocity of the urine on the urethral wall, and the area of the urethral wall to be exposed to the urine. In the present embodiment, there are two external flow channels 15 and two adjacent walls 17 extending therebetween.

The respective external flow channels 15 and walls 17 are substantially the same in shape and dimension and are substantially equally distributed about the circumference of the main body 3. Accordingly, the external flushing portion 13 is symmetrical about a plane extending along the longitudinal axis 19 and each external flow channel 15 and each wall 17 has a diametrically opposed counterpart.

As can most clearly be seen in Figure 8, each external flow channel 15 has a substantially trapezoidal cross-section in the transverse direction with a planar base portion 21 and a pair of adjacent sidewalls 23 which taper outwardly such that the width of the external flow channel 15 increases in the radial direction. As shown, for example, in Figure 1, the sidewalls 23 are linked to the outermost surface of the adjacent walls 17 by rounded transitions 25 which minimise the presence of sharp edges that may otherwise cause discomfort or injury to users of the catheter.

It will be appreciated that other channel shapes are possible and may provide adequate flushing of the urethra. For example, the external flow channels 15 may comprise a base and sidewalls that are angled to form a flow channel with a V-shaped cross-section (which may be referred to as a wedge shape or tapered cross- section) or a square or rectangular shaped cross-section.

As shown in Figures 1 to 5, the external flushing portion 13 extends fully between the insertion portion 9 and the outlet portion 11. In the present embodiment, the insertion portion 9 comprises a solid, cylindrical body having a solid outer wall 27 and extends from the proximal end of the external flushing portion 13 to the terminal end 29 of the catheter 1. The insertion portion 9 may be configured to aid insertion and may comprise one more features or formations to this end. In the embodiment shown in Figure 1, the insertion portion 9 is provided with a rounded terminal end 29 but this is not a limitation, and the terminal end may be provided with a bulb or cone shaped member or a non-circular cross-section to aid insertion of the catheter 1.

The external flow channels 15 are shaped and configured to receive a flow of urine from the user’ s bladder in use and channel the urine towards the outlet portion 11. The proximal ends of the external flow channels 15 are arranged relative to the insertion portion 9 such that the external flow channels 15 extend partially into the bladder upon insertion of the catheter 1 into the bladder. Accordingly, the proximal end of the external flow channels 15 may be positioned within the bladder to receive urine therefrom.

Referring to Figures 6 to 8, the outlet portion 11 comprises an elongate body having a substantially rounded rectangular cross section in the transverse direction. Therefore, the outlet portion 11 comprises four substantially planar external sidewalls 3 la, 3 lb, 33a, 33b extending along the length of the outlet portion 11 from the proximal end to the distal end, parallel to the longitudinal axis. The planar sidewalls 31a, 31b, 33a, 33b are arranged in pairs of substantially parallel, diametrically opposed planar sidewalls. One pair of planar sidewalls 31a, 31b is wider than the other pair of planar sidewalls 33a, 33b such that the body of the outlet portion 11 has an oblong cross section in the transverse direction. Each planar sidewall 31a, 31b, 33a, 33b is substantially perpendicular to the two adjacent planar sidewalls 31a, 31b, 33a, 33b. Each adjacent planar sidewall is linked by a rounded transition or corner 35 which also extends fully along the length of the outlet portion 11 from the proximal end to the distal end.

The dimensions of the planar sidewalls 31a, 31b, 33a, 33b and rounded corners 35 are such that the perpendicular distance between the wider sidewalls 31a, 31b is substantially the same as the outermost diameter of the external flushing portion 13, and such that the perpendicular distance between the narrower sidewalls 33 a, 33b is greater than the outermost diameter of the external flushing portion 13. Accordingly, an upper face 37 of the outlet portion 11 extends in the transverse direction beyond the outermost boundary of the external flushing portion 13 on two diametrically opposed sides thereof. Furthermore, the dimensions of the upper face 37 are such that the distance between the outermost edges of the two extending side portions is greater than the diameter of a typical urethra. Therefore, in use, the two extending side portions of the upper face 37 may entirely cover the urethral opening from one side to the other when the outlet portion 11 is positioned to abut the base of the urethra.

As shown in Figures 5 and 8, the outlet portion 11 comprises an internal cavity 39 which is formed at the centre of the outlet portion 11 and extends longitudinally from the proximal end to the distal end. The distal end terminates at a lower, substantially flat face 41 of the outlet portion 11. The internal cavity 39 comprises an outlet aperture 43 formed in the lower face 41 such that the internal cavity 39 is open at the distal end of the catheter 1 for the exit of urine therefrom. A pair of drainage apertures 45 are formed in the upper face 37 of the outlet portion 11 on diametrically opposed sides. The drainage apertures 45 extend through the upper face 37 and converge into the internal cavity 39 such that a fluid flow path is formed through the outlet portion 11 from each of the drainage apertures 45, through the internal cavity 39 and out through the outlet aperture 43 in the lower face 41 thereof.

The outlet portion 11 is arranged relative to the external flushing portion 13 such that each external flow channel 15 is substantially aligned with a corresponding drainage aperture 45 of the outlet portion 11. Accordingly, in this embodiment, two flow paths for the flow of urine from the insertion end 5 to the outlet end 7 of the catheter 1 are formed by the external flow channels 15, drainage apertures 45, internal cavity 39 and outlet aperture 43. The upper face 37 of the outlet portion 11 is angled on opposite sides to form respective raised edges 47 that extend around each adjacent drainage aperture 45. The upper face 37 is angled toward the respective drainage apertures 45 such that urine flowing from the external flow channels 15 is captured by the upper face 37 and directed toward the corresponding drainage apertures 45.

The profile of the base portion of each drainage aperture is substantially the same as the base portion of the corresponding external flow channel 15 in terms of shape and dimensions so that an unobstructed, continuous flow path is formed from the external flow channel 15 through to the internal cavity 39. The drainage apertures extend radially beyond the outer boundaries of the external flushing portion 13 such that the cross-sectional area of a drainage aperture 45 is greater than that of the corresponding external flow channel 15 in the transverse direction. This enables the drainage apertures 45 to receive urine flowing from the corresponding external flow channels 15 at a sufficient rate to reduce the likelihood of a build-up of urine at the upper face 47 and the potential leakage of urine outside of the catheter 1 at the base of the urethra.

It will be appreciated that the shape and dimensions of the outlet portion may be such that an upper face of the outlet portion extends transversely beyond all external boundaries of the external flushing portion at the junction therebetween. For example, if the external flushing portion comprises four external flow channels equally distributed about the circumference thereof, the outlet portion may be shaped to have a rounded square cross section in the transverse direction so that the upper surface of the outlet portion extends fully around the external flushing portion at a junction therebetween. In this example, four drainage apertures may be formed in the upper surface of the outlet portion and each drainage aperture may be aligned with a corresponding external flow channel so that four flow paths to the internal cavity of the outlet portion are provided. The upper surface of the outlet portion may be similarly angled to form four upper edges that are shaped and arranged to capture urine flowing along the external flow channels and direct the urine into the associated drainage aperture.

In use, the catheter 1 is inserted into the urethra from the insertion end 5 until the insertion portion 9 and the proximal end of the external flushing portion 13 extend into the bladder. The diameter of the insertion portion 9 and outermost diameter of the external flushing portion 13 are substantially the same so that the catheter 1 may be inserted along the urethra without interruption until the upper face 37 of the outlet portion 11 abuts the base of the urethra and the extending side portions of the upper face 37 substantially cover the urethral opening from one side to the other. When positioned correctly, the proximal end of each external flow channel 15 extends into the bladder for the receipt of urine.

The walls 17 of the external flushing portion 13 support the urethral wall and maintain the urethra in an open state. In this position, the urethral wall mates with the open face of the two external flow channels 15 to form flow tunnels along the urethra to the upper face 37 of the outlet portion 11. Accordingly, after insertion and appropriate positioning of the catheter 1, urine may flow from the bladder along the external flow channels 15 out from the urethra and into the internal cavity 39 of the outlet portion 11. Urine flowing along the flow channels 15 contacts the urethral wall, thereby flushing bacteria and other foreign substances external from the urethra.

Urine is, thus, channelled through the internal cavity 39 of the outlet portion 11 and out from the catheter 1 via the outlet aperture 43 formed in the lower face 41 thereof. The outflowing urine may then be directed into a toilet bowl or other receptacle. Optionally, a separate funnel may be attached to the end of the outlet portion 11 to assist with the directing of outflowing urine. One potential benefit of the planar sidewalls is that it may make affixing a funnel easier.

It has been found through experimentation that embodiments of a catheter 1 as hereinbefore described may achieve flow rates of approximately 750ml/min for a catheter size of OHIO (i.e., 3.33 mm diameter) and 790 ml/min for a catheter size of CH 18 (i.e., 6 mm diameter). This is acceptable and, in some cases, better than conventional catheters of a similar diameter with internal rather than external flow channels.

In some embodiments, the catheter is formed of a material of the group comprising: polyvinyl chloride, polytetrafluoroethylene, polyolefins, latex, silicones, synthetic rubbers, polyurethanes, polyesters, polyacrylates, polyamides, thermoplastic elastomeric materials, styrene block copolymers, polyether block amide, thermoplastic vulcanizates, thermoplastic copolyesters, thermoplastic polyamides, and water disintegrable or enzymatically hydrolysable material, or combinations, blends or copolymers of any of the above materials.

In preferred embodiments, the catheter is formed of a material of the group comprising: polyolefins, polyesters, poly acrylates, polyamides, thermoplastic elastomeric material, polyether block amide, thermoplastic vulcanizates, thermoplastic copolyesters, thermoplastic polyamides, fluororubber, and water disintegrable or enzymatically hydrolysable material or combinations, blends or co-polymers of any of the above materials.

In some embodiments, said water disintegrable or enzymatically hydrolysable material comprises a material of teh group comprising: polyvinyl alcohol, extrudable polyvinyl alcohol, poly aery lie acids, polylactic acid, polyesters, polyglycolide, polyglycolic acid, poly lactic-co-glycolic acid, polylactide, amines, polyacrylamides, poly(N-(2-Hydroxypropyl) methacrylamide), starch, modified starches or derivatives, amylopectin, pectin, xanthan, scleroglucan, dextrin, chitosans, chitins, agar, alginate, carrageenans, laminarin, saccharides, polysaccharides, sucrose, polyethylene oxide, polypropylene oxide, acrylics, polyacrylic acid blends, poly(methacrylic acid), polystyrene sulfonate, polyethylene sulfonate, lignin sulfonate, polymethacrylamides, copolymers of aminoalkyl-acrylamides and methacrylamides, melamine-formaldehyde copolymers, vinyl alcohol copolymers, cellulose ethers, poly-ethers, polyethylene oxide, blends of polyethylene- polypropylene glycol, carboxymethyl cellulose, guar gum, locust bean gum, hydroxypropyl cellulose, vinylpyrrolidone polymers and copolymers, polyvinyl pyrrolidone-ethylene-vinyl acetate, polyvinyl pyrrolidone- carboxymethyl cellulose, carboxymethyl cellulose shellac, copolymers of vinylpyrrolidone with vinyl acetate, hydroxyethyl cellulose, gelatin, poly-caprolactone, poly(p-dioxanone), or combinations, blends or co-polymers of any of the above materials. In some preferred embodiments, the catheter is formed of a polyolefin material, especially polyethylene and/or polypropylene. In some preferred embodiments, the catheter is formed of a thermoplastic elastomeric material. In some preferred embodiments the catheter may be made from a polyolefin based synthetic thermoplastic polyolefin elastomer (TPE) containing a hydrophilic additive. In some preferred embodiments the catheter may be made from a polymer mixture comprising a first polymer and a second polymer, wherein the first polymer is a thermoplastic or thermo-curing polymer, and the second polymer is an amphiphilic block copolymer possessing both hydrophilic and lipophilic properties. A possible suitable polymer mixture is described and disclosed in EP2493521A1.

The insertion end of an alternative embodiment of the invention is shown in figure 9. The embodiment of figure 9 is in many respects the same as that of figures 1- 8 and therefore only the differences are described, and like reference numerals (incremented by 100) are used for like features. In this example, the insertion portion is not solid and instead comprises a hollow body defining one or more inner lumens and corresponding inlets, or eyelets formed through the external wall of the insertion portion. Referring to Figure 9, the insertion portion 109 of the insertion end 105 may be hollow and define a central inner lumen extending longitudinally through the insertion portion 109. The inner lumen may be closed at the insertion end 129 and open at the junction between the insertion portion 109 and the external flushing portion 113. One or more eyelets 149 may be formed through the external wall 127 of the insertion portion 109 and into the inner lumen. The open end of the inner lumen may be open to the external flushing portion 113 such that a fluid flow path for the flow of urine is formed from the or each eyelet 149 to one or more of the plurality of external flow channels 115.

A space 151 may be formed through the body of the external flushing portion 113 at a position local to the junction between the insertion portion 109 and the external flushing portion 113 such that a gap is formed between the inner lumen and the external flow channels 115. The space 151 may comprise a channel extending entirely through the body of the external flushing portion 113 in the transverse direction from the proximal end of one external flow channel 115 to the proximal end of the opposite flow channel 115. Thus, the inner lumen may be separated from the external flow channels 115 in the longitudinal direction. The result is that urine exiting the inner lumen must traverse the space 151 to enter the external flow channels 115. Advantageously, providing the space 151 between the inner lumen and the external flow channels 115 reduces the risk of the flow path therebetween becoming blocked by the wall of the urethra. Since a flow path is formed between the eyelets 149 and the external flow channels 115 through the inner lumen, it will be appreciated that the proximal ends of the external flow channels 115 need not be partially located within the bladder to receive urine therefrom and may instead receive urine from the bladder exclusively via the eyelets 149 and inner lumen. In all other respects, this alternative embodiment may share the same features as the above-described embodiment.

The catheters 1 of the invention may be manufactured by injection moulding using the materials outlined above. In the injection moulding method, the tool may be arranged to position the split line where the injection mould tool closes during moulding and opens for ejection of the part on the flat surfaces 31a, 31b, 33a, 33b.

The one or more embodiments are described above by way of example only. Many variations are possible without departing from the scope of protection afforded by the appended claims.

Claims

1. A catheter comprising: an elongate main body having an insertion end for insertion into a urethra and an outlet portion at an outlet end, the outlet portion comprising an inner cavity through which fluid may flow from the catheter and a plurality of external sidewalls, wherein at least one of the plurality of external sidewalls is planar.

2. The catheter of claim 1, wherein the outlet portion comprises four planar external sidewalls.

3. The catheter of claim 1 or claim 2, wherein an interface between two adjacent planar external sidewalls is curved.

4. The catheter of any preceding claim, wherein at least two planar external sidewalls are parallel.

5. The catheter of any preceding claim, wherein at least two planar external sidewalls are perpendicular.

6. The catheter of any preceding claim, wherein the plurality of planar external sidewalls extend fully along the length of the outlet portion.

7. The catheter of any preceding claim, wherein there are two pairs of planar external sidewalls, and wherein each planar external sidewall of one pair is perpendicular to each planar external sidewall of the other pair.

8. The catheter of any preceding claim, wherein the cross-section of the outlet portion in the transverse direction is oblong.

9. The catheter of any preceding claim wherein the outlet portion is between 30 mm and 50 mm long.

10. The catheter of any of claims 2-9 wherein two of the four planar external side walls are longer than the other two planar external sidewalls.

11. The catheter of any preceding claim, further comprising an external flushing portion between the insertion end and the outlet portion, the external flushing portion comprising an external flow channel, wherein the external flow channel is in fluid communication with the inner cavity via a corresponding drainage aperture formed at a junction between the external flushing portion and the outlet portion. The catheter of claim 11, wherein the outlet portion is shaped at the junction to guide liquid from the external flow channel toward the corresponding drainage aperture. The catheter of claim 12, wherein the outlet portion is angled at the junction to guide liquid from the external flow channel toward the drainage aperture. The catheter of any of claims 11 to 13, wherein the outlet portion is shaped at the junction to collect liquid flowing along the external flow channel. The catheter of any of claims 11 to 14, comprising a plurality of external flow channels and a plurality of corresponding drainage apertures. The catheter of claim 15, comprising two external flow channels and two corresponding drainage apertures. The catheter of any of claims 11 to 16, wherein each external flow channel comprises a straight and/or helical portion. The catheter of any of claims 11 to 17, wherein each external flow channel is aligned with a corresponding drainage channel. The catheter of any of claims 11 to 18, wherein the shape of a base portion of each external flow channel is the same as the shape of a base portion of the corresponding drainage aperture. The catheter of any of claims 11 to 19, wherein each drainage aperture extends axially and/or radially. The catheter of any of claims 11 to 20, comprising one or more walls each having an external surface arranged, in use, to contact the urethral wall and support the urethra in an open state. The catheter of any of claims 11 to 21, wherein the insertion end has an insertion portion comprising an inner lumen in fluid communication with the or each external flow channel, and wherein the insertion portion comprises one or more eyelets formed in an external surface thereof and extending through to the inner lumen of the insertion portion. The catheter of claim 22, wherein the insertion portion comprises two eyelets arranged on opposite sides respectively of the insertion portion. The catheter of claim 22 or claim 23, wherein at least two eyelets are longitudinally offset The catheter of any preceding claim wherein the catheter is an intermittent urinary catheter. A method of manufacturing a catheter according to any previous claim by injection moulding, the method comprising the step of positioning the split line of the injection moulding tool on a planar surface of the catheter.