Urinary flow control device

Abstract

A device (100) for controlling urinary flow, comprising: a fluid inlet (102); a fluid outlet (104); a valve movable between an open position and a closed position; an actuator operable to move the valve between the open and closed positions; and a casing (106) positioned on a first side of the fluid inlet (102), the casing (106) comprising a first section (110) resiliently connected to a second section (112) by a first flexible neck portion (116), the first and second sections (110, 112) each having a higher rigidity than the first flexible neck portion (116); wherein the fluid outlet (104) is positioned on a second, opposite side of the fluid inlet (102). The device may be insertable into a urethra for installation in a user's bladder and urethra and arranged such that the casing is located in a bladder. The device can be inserted and extracted from a user without requiring intrusive surgery, allowing the device to be readily replaced, when needed.

Description

[0001] Urinary flow control device

[0002] FIELD

[0003] The present invention relates to urinary flow control devices, particularly for people with urinary incontinence, but also for people with urinary retention.

[0004] BACKGROUND

[0005] One of the causes of urinary incontinence (Ul) - the involuntary leakage of urine - is the loss or weakening of the urethral sphincter which affects approximately 5% of people around the globe. In men, Ul is particularly common in people with prostate cancer who have undergone a prostatectomy, affecting approximately 10% of patients undergoing prostatectomy annually in the USA. Ul is also a common problem for patients with an enlarged prostate, affecting 30-40% of patients undergoing transurethral resection of the prostate (TURP) annually in the USA. In women, pregnancy and childbirth may lead to weak pelvic floor muscles or damage to the surrounding nerves which can make the urethral sphincter incompetent. Ul severely affects the quality of life in patients of all ages.

[0006] Various methods exist for treating Ul, each with its own inherent problems. A common, cheap solution is the use of diapers, which simply absorb any leaked urine, before being disposed of by a user. Diapers do not offer a long-term solution, as they need to be replaced regularly. Additionally, the use of diapers generates excessive waste due to each diaper requiring disposal after one use.

[0007] Catheters offer a short-term solution. A catheter is a soft hollow tube which may be passed into the bladder in order to drain urine, among other uses. Catheters offer only a short-term solution, as with long-term use various issues may arise, including urinary tract infections (UTIs) and flow disruption due to mineral deposition within the catheter. A catheter also simply directs the urine flow to a receptacle (usually worn) outside the patient’s body without providing any control over the flow.

[0008] Surgically implanted devices are also known, for example that may be inserted into the body via surgery. One such procedure provides a user-controllable urethral constriction cuff in order to control the flow of urine out of the bladder. This provides a solution for some patients, but there are inherent risks with surgery, as well as costs.

[0009] Urinary retention is the inability to fully empty the bladder. This can lead to discomfort and other complications. Urinary retention can have various causes. These include obstructive causes in which the urine flow path from the bladder is blocked, e.g. benign prostatic hyperplasia, urethral strictures and tumours in the pelvic region. There are also neurological causes, e.g. spinal cord injury, multiple sclerosis, stroke and Parkinson’s disease, and there are muscle dysfunction causes, e.g. detrusor muscle underactivity (the bladder muscle fails to contract, hindering expulsion of urine) and pelvic floor dysfunction (weakness or coordination issues within pelvic floor muscles can prevent complete bladder emptying).

[0010] SUMMARY OF THE INVENTION

[0011] When viewed from a first aspect, the present invention provides a device for controlling urinary flow, comprising: a fluid inlet; a fluid outlet; a valve movable between an open position in which fluid can flow from the fluid inlet to the fluid outlet and a closed position in which fluid flow is blocked between the fluid inlet and the fluid outlet; an actuator operable to move the valve between the open position and the closed position; and a casing positioned on a first side of the fluid inlet, the casing comprising a first section resiliently connected to a second section by a first flexible neck portion, the first and second sections each having a higher rigidity than the first flexible neck portion; wherein the fluid outlet is positioned on a second, opposite side of the fluid inlet.

[0012] In a set of embodiments, the device is insertable into a urethra for installation in a user’s bladder and urethra and arranged such that, in use, the casing is located in a bladder. This may advantageously enable the device to be inserted and extracted from a user without requiring intrusive surgery, allowing the device to be readily replaced, when needed, and reducing the risk to the user. The present invention provides a urinary flow device where the casing on the first side of the fluid inlet is not formed as a single rigid structure, but instead has a level of flexibility provided by the flexible neck portion. This may advantageously enable the casing to flex when it comes into contact with a bladder wall (e.g. due to movement of a user, contraction of the bladder, etc), increasing overall comfort for a user and decreasing the risk of damage to the bladder while the device is installed by reducing the force applied to the bladder wall by the casing. It may also advantageously allow the casing to flex during insertion or extraction of the device through a urethra, improving overall installation ease and comfort, and decreasing the risk of damage to the urethra during insertion or extraction.

[0013] The casing may provide a suitable location for one or more components of the device to be held therein, e.g. actuators, energy storage devices, control circuitry, antennas, etc. The casing and the fluid outlet being positioned on opposite sides of the fluid inlet may advantageously ensure that such components do not obstruct the flow path between the fluid inlet and the fluid outlet. The cross-sectional area of the conduit between the fluid inlet and the fluid outlet can thus be maximised. This may allow a high flow rate (i.e. a relatively normal urination flow rate) to be achieved compared with existing devices. Such an improved flow rate may give an improved quality of life for the user as the urination process is much closer to normal.

[0014] In a set of embodiments, the casing further comprises a third section resiliently connected to the second section by a second flexible neck portion. This may advantageously increase the overall size of the casing, allowing additional components to be housed therein, while retaining the aforementioned advantages of allowing the casing to flex. It may also provide a greater range of motion for the casing by allowing it to flex at multiple positions along its length, thus further improving comfort and reducing the risk of damage while the device is installed and / or is being inserted / removed from a user.

[0015] In a set of embodiments, each section of the casing is elongate. In other words, each section of the casing may have a length along a longitudinal axis which is greater than a width or depth along a lateral axis. This may advantageously aid ease of installation and reduce risk of damage to the urethra during insertion or extraction, since this may reduce the pressure applied to the urethral wall during installation.

[0016] In a set of embodiments, each section of the casing is substantially rigid. This may allow each section of the casing to provide sufficient protection to any components housed therein from bending forces while installed in a user or during installation.

[0017] In a set of embodiments, the casing forms an overall curved shape when the or each flexible neck portion is in a non-stressed position. It will be appreciated that the term “non-stressed” is used herein to refer to the position a particular component or part naturally takes when no external force is applied thereto. In a set of embodiments, the second section of the casing is positioned at an angle relative to the first section when the flexible neck portion is in a non-stressed position. In a set of embodiments, each respective section of the casing is positioned at an angle relative to the adjacent sections connected thereto by a flexible neck portion when the flexible neck portions are in a non-stressed position. The relative angle between sections of the casing when the flexible neck portions are each in a non-stressed position may be greater than 0°, preferably greater than 10°, preferably greater than 20°, and it may be less than 45°, preferably less than 40°, e.g. equal to 30°. Such embodiments may advantageously ensure that any force applied to the casing that is likely to occur while it is installed in a user causes it to bend or flex, thus increasing overall comfort for a user and decreasing risk of damage to the bladder wall by reducing the force applied to the bladder wall by the casing.

[0018] In a set of embodiments, each flexible neck portion permits bending around at least one axis. Said at least one axis may be perpendicular to a longitudinal axis of a respective section of the casing connected thereto. Each flexible neck portion may preferably permit bending around at least two axes, preferably around any axis perpendicular to said longitudinal axis. Such embodiments may help provide the above-mentioned advantages of allowing the casing to flex or bend when force is applied thereto.

[0019] In a set of embodiments, each flexible neck portion permits bending around the at least one axis by up to 45° from a non-stressed position of said flexible neck portion. This may advantageously enable each section of the casing to have a sufficient range of motion relative to the adjacent section(s) in order to accommodate any forces which are likely to occur during insertion, extraction, or while the device is installed in a user, whilst also ensuring that the flexible neck portions are sufficiently resilient to ensure the casing returns to its non-stressed shape once any forces applied thereto are removed.

[0020] In a set of embodiments, each flexible neck portion permits a relative twisting motion between the respective sections connected thereto. This may advantageously add an additional degree of freedom for relative motion of adjacent sections of the casing, further improving the ability for the casing to accommodate any torques applied thereto during insertion, extraction, or while the device is installed in a user.

[0021] In a set of embodiments, each flexible neck portion permits a relative twisting motion between the respective sections connected thereto by up to 30°, preferably up to 45°, preferably up to 60°, preferably up to 90°, from a non-stressed position of the flexible neck portion. This may advantageously enable each section of the casing to have a sufficient relative range of motion to the adjacent section(s) in order to accommodate any torques which are likely to occur during insertion, extraction, or while the device is installed in a user, whilst also ensuring that the flexible neck portions are sufficiently resilient to ensure the casing returns to its nonstressed shape once any torques applied thereto are removed.

[0022] In a set of embodiments, each flexible neck portion has a minimum cross-sectional area that is smaller than a minimum cross-sectional area of a respective section of the casing connected thereto. This may advantageously enable each flexible neck to provide the aforementioned bending and / or twisting motions without protruding outwardly from the sections, thus improving ease of installation and reducing risk of damage.

[0023] In a set of embodiments, each flexible neck portion, when in a non-stressed position, has a substantially hourglass-like shape. This may advantageously enable each flexible neck portion to seamlessly connect to each adjacent section of the casing (i.e. without any sharp or angled external edges which could damage a user during insertion, extraction, or while the device is installed in a user), thereby increasing comfort and reducing risk of damage, while ensuring that the flexible neck portions can bend and / or twist without any significant folding thereof which could damage the material used for the flexible neck portions. Alternatively, each flexible neck portion may have a recessed portion on only one side thereof, when in a non-stressed position. This may improve ease of manufacture.

[0024] In a set of embodiments, each flexible neck portion has a substantially circular cross-section when viewed along a longitudinal axis thereof at a waist thereof. This may also advantageously help ensure that the device does not have any sharp or angled edges which could cause damage to a user during insertion, extraction, or while installed in a user. It may also help enable the flexible neck portions to permit the bending and / or twisting around a plurality of axes and in a plurality of directions.

[0025] In a set of embodiments, each flexible neck portion may form a conduit between adjacent sections. Each flexible neck portion may be at least partially hollow. This may advantageously enable one or more components - e.g. wires - to extend or pass through the flexible neck portions, thus allowing components contained in one section of the casing to be operably coupled to components contained in another section of the casing. In such embodiments, the casing or part of the casing may form a single continuous cavity for housing one or more components therein. Each flexible neck portion may be filled with a soft material that permits bending and prevents or reduces gas within the flexible neck portion. Avoiding gas in the flexible neck portions is desirable as they may need to be made from a gas permeable material and it is desirable to avoid gas leaking into a user after installation. The soft material may be inserted into the casing after one or more components have been inserted through the flexible neck portions in order to remove gas from within the flexible neck portions.

[0026] In a set of embodiments, at least one of the sections is at least partially hollow. This may allow one or more components to be contained therein. At least one of the sections may be filled with material in order to reduce or remove a volume of gas held therein. The material may be inserted into the casing after one or more components have been inserted into the casing in order to remove gas from within the sections of the casing. The material used to fill the interior of the sections of casing may be the same as the material used to fill the interior of the flexible neck portions.

[0027] In a set of embodiments, at least one of the sections of the casing and / or the flexible necks contains one or more moisture-absorbent materials. The inclusion of such moisture-absorbent materials may help ensure that any leakage of fluid into the casing does not damage any components housed therein e.g. due to shortcircuiting, corrosion, etc.

[0028] In a set of embodiments, at least one of the sections is shaped to conform to the shape of one or more components housed therein (e.g. the actuator, a battery, etc.). At least one of the sections, and optionally all of the sections, may have a substantially smooth outer surface, thus avoiding damage and / or discomfort to a user during insertion or extraction, or while the device is installed in a user.

[0029] In a set of embodiments, at least one of the sections is substantially tube-shaped. At least one of the sections may have a circular cross-section when viewed along a longitudinal axis thereof. Such embodiments may advantageously ensure that the casing does not have any sharp or angled edges which could damage or cause discomfort to a user thereof during insertion, extraction or while installed in the user.

[0030] In a set of embodiments, each section of the casing is made from a suitable biocompatible material. In a set of embodiments, each section of the casing is made from the same type of material as the flexible neck portions. In a set of embodiments, the flexible neck portions are made from the same type of material as the sections of the casing but from a thinner material and / or material with a lower hardness rating. In a set of embodiments, the sections of the casing and the flexible neck portions are made of silicone. In a set of embodiments, the sections of the casing and the flexible neck portions are made of silicone, with the flexible neck portions having a lower hardness rating and / or wall thickness than the sections of the casing. In a set of embodiments, the sections of the casing and the flexible neck portions are integrally moulded. In a set of embodiments, the sections of the casing and the flexible neck portions are made of silicone and are integrally moulded. In a set of embodiments, the sections of the casing and the flexible neck portions are made of silicone and are integrally moulded, with the flexible neck portions having a lower hardness rating and / or wall thickness than the sections of the casing.

[0031] In a set of embodiments, at least one of the sections has a substantially rectangular cross-section when viewed along a longitudinal axis thereof. In a set of embodiments, the section of the casing which is furthest away from the fluid inlet - i.e. the section of the casing which is first inserted into the urethra during insertion - has a substantially rectangular cross-section when viewed along a longitudinal axis thereof. Such a shape may align more closely to the cross-sectional shape of a typical urinary meatus, i.e. the opening of the urethra (which is not circular but slightly elongate), and may thus reduce the pressure applied to the urinary meatus when said section is inserted and ensure that the meatus is sufficiently deformed for subsequent insertion of the remainder of the device. This may therefore improve ease of installation and decreasing risk of damage during insertion or extraction. This may also advantageously enable said section to house a commercially available battery - which are typically rectangular in cross-section - without significant dead space within the section. This may allow the cross-sectional area of the section to be kept to a minimum, thereby improving ease of installation and decreasing risk to a user during insertion or extraction.

[0032] In a set of embodiments, the substantially rectangular cross-section has rounded corners. This may ensure that the device does not have any sharp or angled external edges which could cause harm to a user during insertion, extraction, or while installed in a user.

[0033] The section having the substantially rectangular cross-section may be the section furthest away from the fluid inlet. That section may be rounded at an end thereof furthest away from the fluid inlet.

[0034] In use, the device allows the flow of urine from the bladder through the urethra to be controlled by operation of the valve. The fluid inlet is arranged inside the bladder so that urine within the bladder can enter the device through the fluid inlet. When the valve is in the closed position, further onward flow of urine is blocked such that urine remains held within the bladder. When the valve is in the open position, a flow path is formed between the inlet and the outlet such that urine in the bladder can flow into the device through the fluid inlet, past the valve and out of the device through the fluid outlet so as to empty urine from the bladder.

[0035] In a set of embodiments, the actuator is contained within the casing. In a set of embodiments, the actuator is contained within the section of the casing located closest to the fluid inlet. This may ensure that the actuator is located physically close to the valve, thus reducing the overall mechanical complexity of the device. The actuator may be positioned on the opposite side of the fluid inlet to the fluid outlet. This relative positioning of the actuator, the fluid inlet and the fluid outlet may ensure that the actuator does not obstruct the flow path between the fluid inlet and the fluid outlet, thereby allowing a high flow rate (i.e. a relatively normal urination flow rate) to be achieved. Operation of the actuator to move the valve to the open position equates to relaxing of the urethral sphincter muscle in a healthy patient. Urination can then proceed at a substantially normal rate until the bladder is empty. The valve can subsequently be closed again to retain urine in the bladder once more.

[0036] When used for treating urinary retention, the urethral blockage (which may be the sphincter muscle itself or other blockages such as the prostate or tumours as discussed above) is counteracted, e.g. by positioning a sufficiently rigid tube in the urethra to hold the urethra open. With the urethra now open to flow, the valve and actuator are then used to control the flow so as to permit or prevent flow and thus enable selective urination.

[0037] The actuator being operable to move the valve between the open position and the closed position means that the actuator is operable to move the valve from the open position to the closed position and from the closed position to the open position.

[0038] In a set of embodiments, the actuator is separated from the valve by a seal. The actuator may be located within a hermetically sealed compartment. The actuator may thus be sealed against contact with urine. In some embodiments the sealed compartment seals against liquid and gas so that the actuator is completely isolated from the valve. By sealing the actuator against contact with any liquid or gas that could contact the body, the actuator (or the inside of the compartment) does not need to be sterilized. The actuator can also be made more energy efficient as it can experience less resistance to its motion due to fluid. This in turn means that it can be operated faster, thus saving energy. In addition, with the actuator being hermetically sealed, different actuator designs are possible which can improve energy efficiency. In such embodiments, the actuator may be arranged to move the valve in a non-contact manner. For example, the actuator may be arranged to move the valve using electrostatic and / or magnetic forces. In a set of embodiments, the actuator comprises at least one movable magnet which can be moved between a first configuration in which it attracts the valve and a second configuration in which it repels the valve. Thus by moving the magnet between the first and second configurations, the valve can be opened and closed. In some embodiments, the movable magnet may be a rotatable magnet that is rotatable between the first and second configurations. In some examples, rotation of the rotatable magnet may change the polarity of the pole that faces the valve. The actuator may be moved by various mechanism. For example, the actuator may be moved by a motor or by a solenoid.

[0039] In a set of embodiments, the device comprises control circuitry operably coupled to the actuator and optionally to the energy storage device. In a set of embodiments, the control circuitry is contained within the casing. In a set of embodiments, the control circuitry is contained within the section of the casing located closest to the section containing the actuator. This may ensure that the control circuitry is located physically close to the actuator, thus reducing the overall electronic complexity of the device.

[0040] In a set of embodiments, the control circuitry is communicable with a wireless communications device located outside of the body so as to enable control over the actuator using said wireless communications device. The device may further comprise an antenna, operably coupled to the control circuitry, and the antenna may be contained within the same section of the casing as the control circuitry. This may advantageously provide a convenient mechanism for a user to operate the control of the valve (e.g. when they feel an urge to urinate), providing a close-to- normal urinating experience for the user. In a set of embodiments, the device comprises a plurality of antennas operably coupled to the control circuitry. This may allow communication with multiple external devices and / or over multiple frequencies. Each antenna may be contained within the same section of the casing as the control circuitry.

[0041] In a set of embodiments, the device further comprises an energy storage device, coupled to the control circuitry. In a set of embodiments, the energy storage device is contained within the section of the casing located furthest away from the fluid inlet. This may provide power to the control circuitry, and to the actuator, enabling the device to remain in situ for a significant portion of time. The energy storage device may comprise a battery, and it may be located in the section of the casing having the substantially rectangular cross-section as mentioned previously.

[0042] The control circuitry may be communicable with a mobile device, e.g. a smartphone, to enable control of the valve using e.g. an app on the mobile device. This may allow data exchange between the urinary flow device and the user’s mobile device in order to allow e.g. use history, battery level, etc. to be stored and displayed to the user and / or to a physician. The device may comprise one or more sensors - e.g. temperature sensors, pressure sensors, flow rate sensors, chemical sensors, etc. - whose outputs may be wirelessly communicated to the mobile device in order to allow a detailed analysis of the functioning of the device and / or the user’s urinary tract. This may allow monitoring of, for example, whether the urinary flow device is functioning correctly, and provide a convenient mechanism for determining when it is time for the device to be replaced. This information may be available to the user and may be communicated to a physician or doctor (e.g. uploaded to a cloud), thus enabling the device to be monitored in situ without requiring a visit to the physician or doctor.

[0043] In a set of embodiments, the first section of the casing is connected to a valve section comprising the fluid inlet and the valve, at least a portion of the valve section being positioned within the first section. This may allow the casing and the valve section to be manufactured separately, and / or from different materials, and assembled together thereafter, providing a convenient method for manufacturing the device. The valve section may be formed from a biocompatible, non-corrodible material, e.g. stainless steel, titanium or a polymer. The connection of the first section of the casing to the valve section may provide a sealed or water-tight connection, thus ensuring that the casing provides a sealed compartment for various components of the device in order to avoid damage thereto. The first section of the casing may be rigidly connected to the valve section.

[0044] In a set of embodiments, the fluid inlet is formed in a side wall of the valve section. This may advantageously enable the fluid inlet to be located close to a urethral opening of the bladder (the urethral neck) when the device is installed in a user, thereby allowing close to full evacuation of the bladder when the valve is opened with minimal pooling of urine remaining within the bladder e.g. beneath the fluid inlet. In a set of embodiments, the fluid inlet comprises a plurality of holes formed in a side wall of the valve section, e.g. four, six, or eight holes. The plurality of holes of the fluid inlet may be evenly distributed circumferentially around the valve section.

[0045] In a set of embodiments, the device further comprises a resilient outlet tube extending between the fluid inlet and the fluid outlet. The outlet tube being resilient may enable it to deform as required in order to conform to the shape of the urethra as the user moves, thereby improving comfort for the user and decreasing risk of damage to the user.

[0046] In a set of embodiments, the device is arranged such that, in use, a majority of (or all of) the outlet tube is located in the urethra, with the outlet tube being arranged to inhibit movement of the device towards the bladder. The outlet tube may therefore provide a convenient positioning mechanism for preventing the device from entering into the bladder, advantageously ensuring that the device remains in place in use and does not e.g. fully enter into the bladder thus preventing the device from being used to control urinary flow out of the bladder through the urethra.

[0047] In a set of embodiments, the resilient outlet tube is attached to the valve section. In a set of embodiments, the resilient outlet tube is releasably attached to the valve section. This may enable a physician, doctor or nurse who inserts and installs the device in a user to exchange the resilient outlet tube with tubes of different sizes and / or shapes in order to more closely match the anatomy of the user in question. Various forms of releasable attachment mechanism may be used. For example, a screw thread or a bayonet mechanism could be used to attach the valve section to the outlet tube. However, for speed and security of attachment, a clip mechanism is used in some embodiments to releasably attach the resilient outlet tube to the valve section. A clip mechanism may be a snap-on mechanism in which one part is pushed into or onto the other part until a clip engages to secure the two parts together. In some embodiments the valve section is inserted inside the outlet tube as this reduces the risk of leakage. In some embodiments the clip mechanism comprises one or more tongues on one part, e.g. the outlet tube, the tongues being arranged to be biased away from their natural, i.e. non-stressed, position during the engagement process, i.e. during the process of attaching to a structure present on the other part (e.g. the valve section). The tongues may be arranged to return towards their non-stressed position in the clipped state, in which the two parts (e.g. the outlet tube and the valve section) are releasably attached. In the clipped state, the one or more tongues may be in a hooked engagement with a structure present on the other part so that release is hindered. The hook may be on the tongues so as to hook the other part, or the hook may be formed on the other part so as to hook the tongues. In the clipped state, a shoulder surface on one part may be in contact with a hook surface on the other part. The angle that these surfaces make to the engagement direction may determine the ease with which the two parts may be disengaged. For example, if the shoulder surface is substantially perpendicular to the engagement direction then separation of the two parts by pulling them apart may be very difficult or impossible. A lower angle may allow a pulling force to bias the tongues away from their non-stressed position to permit disengagement. The clip mechanism may comprise a cylindrical tube provided inside the outlet tube, the cylindrical tube having one or more tongues angled radially inwardly in their nonstressed position and being deformable radially outwardly by insertion of the valve section through the cylindrical tube. The valve section may have a flange at the end which engages and is attached to the outlet tube, the flange having a larger diameter than the rest of the valve section part that inserts inside the outlet tube, the flange section pressing the tongues radially outwardly as it is inserted through the cylindrical tube and the flange section providing the hook surface that engages with the shoulder surface on the distal end of the tongues once it has been inserted beyond the tongues (and the tongues have sprung back radially inwardly towards their non-stressed position).

[0048] Alternatively, in another set of embodiments the resilient outlet tube is fixedly (or permanently) attached to the valve section. In such embodiments the device may be manufactured in different sizes, and a physician, nurse or doctor may select a device having an outlet tube of the appropriate size for the anatomy of the user in question.

[0049] In a set of embodiments, at least a portion of the valve section is positioned within a portion of the outlet tube when the outlet tube is attached to the valve section. Such a connection may advantageously provide a sealed or water-tight connection between the valve section and the outlet tube, thereby ensuring that urine passes from the fluid inlet to the fluid outlet without leaking out from the side of the device and e.g. becoming trapped in the urethra, thus helping avoid potential health risks.

[0050] In a set of embodiments, the outlet tube, when in a non-stressed position, comprises a substantially straight portion extending from the fluid inlet and a curved portion located between the substantially straight portion and the fluid outlet. In other words, the outlet tube may be substantially J-shaped. Such a shape may align with the typical shape of the urethra exiting from the bladder in male users, and thus provide the above-mentioned functionality of inhibiting movement of the device towards the bladder through the interaction of the outlet tube with the natural shape of the urethra. Such embodiments may therefore be particularly suitable for male users of the device.

[0051] In a set of embodiments, the curved portion of the outlet tube permits bending around at least one axis. In a set of embodiments, the curved portion of the outlet tube may permit bending around at least one axis in order to straighten the outlet tube. Such embodiments may advantageously improve ease of insertion and extraction, since the outlet tube may straighten or bend as required to match the shape of the urethra during insertion and extraction, thus reducing the force exerted on the urethra by the outlet tube as it moves therethrough during insertion or extraction.

[0052] It will be appreciated that the device described herein is not exclusively for male anatomy and can equally be applied to female anatomy. A device configured for female anatomy may have an outlet tube which is substantially straight rather than J-shaped so that it more closely matches the shape of a female urethra. In some embodiments the outlet tube of such a female device may provide enough resistance to inhibit movement of the device towards the bladder, but in other embodiments, if additional security is required to hinder such movement then a retainer may be provided that remains outside the body and is arranged to inhibit movement of the device towards the bladder. In some embodiments the retainer may take the form of one or more structures that extend perpendicularly from the outlet tube adjacent to the fluid outlet. The one or more structures may comprise a plate structure. The one or more structures may be shaped to conform with a typical female anatomy and / or for improved comfort.

[0053] In a set of embodiments, the fluid outlet is positioned at an end of the resilient outlet tube furthest from the fluid inlet. That end of the resilient outlet tube may be laterally compressible so as to allow partial collapse of the fluid outlet. This may ensure that the outlet tube can be laterally compressed as required in order to prevent it exerting too much force on the urethra during insertion, extraction, or when the device is installed in a user.

[0054] In a set of embodiments, the outlet tube comprises a tapering portion located towards the fluid outlet, the tapering portion narrowing towards the fluid outlet. This may advantageously reduce the pressure applied by the fluid outlet at the end of the outlet tube to the urethral wall during removal of the device from a user, thus improving comfort and reducing risk of damage as well as improving ease of extraction.

[0055] In a set of embodiments, the outlet tube comprises a portion of reinforcing material located near to the fluid outlet. The portion of reinforcing material may comprise a reinforcing ring. The reinforcing material may be embedded within a side wall of the outlet tube. The reinforcing material may enclose a portion of the flow path between the fluid inlet and the fluid outlet. The reinforcing material may permit lateral compression and resist expansion. Thus, the reinforcing material may provide sufficient structural rigidity to the outlet tube to enable an extraction tool having an expanding member located at an end thereof to be inserted into the urine outlet at the end of the outlet tube and expanded in order to frictionally grip the device and enable extraction thereof. The use of such an extraction tool may be more difficult without the presence of such a reinforcing material since the material used for the majority of the outlet tube may be too flexible to provide enough friction between it and the expanding member of the tool to enable the device to be extracted through the urethra. In a set of embodiments, the portion of reinforcing material is made from ePTFE. In other embodiments, the portion of reinforcing material may be made from other materials, e.g. nylon, polyester, nitinol, steel, etc.

[0056] In a set of embodiments, the outlet tube comprises one or more holes in a side wall thereof located near to the fluid outlet. These holes may provide a convenient mechanism for fastening a suture or thread or flexible line to the outlet tube for use in insertion and / or extraction of the device.

[0057] In a set of embodiments, the outlet tube may be sufficiently stiff (or may have at least a portion which is sufficiently stiff) that it can maintain its shape and / or form so as to maintain a flow path even in the presence of obstructions. For example, when used for treating urinary retention, the stiffness may be selected to ensure a flow path to bypass a physical obstruction such as a tumour or enlarged prostate or to counter the constriction of a sphincter muscle. If required, different outlet tubes with different physical characteristics (e.g. different stiffnesses) can be made available to the physician so that an appropriate or optimal outlet tube can be selected for the condition being treated and can be attached to the valve section.

[0058] In a set of embodiments, the outlet tube comprises a constricted portion arranged such that, in use, it is located substantially adjacent to a urethral sphincter. This constricted portion may also aid in positioning the device (both in urinary incontinence treatments and urinary retention treatments), as the urethral sphincter may grip the constricted portion and thus inhibit the device from moving towards the bladder and / or towards the urethra in view of non-constricted portions adjacent thereto. This grip may also provide a seal between the bladder wall and the device, preventing urine from passing into the urethra around the exterior of the device. The outlet tube may comprise a tapering portion which widens from a first cross- sectional area at the constricted portion to a second, larger cross-sectional area at a location more distal (i.e. closer to the fluid outlet) along the outlet tube. This may avoid any sharp edges on the exterior surface of the outlet tube.

[0059] In a set of embodiments, the constricted portion of the outlet tube comprises reinforcing material arranged to inhibit kinking and / or constriction of the constricted portion. The reinforcing material may be integrated into a wall of the constricted portion, it may be located adjacent to an interior face of the wall of the constricted portion, or it may be located adjacent to an exterior face of the wall of the constricted portion. The reinforcing material may advantageously ensure that the constricted portion does not significantly bend or kink during insertion and / or removal of the device, thus improving comfort and reducing risk of damage during insertion / extraction. The reinforcing material may advantageously ensure that the constricted portion does not collapse under pressure from the urethral sphincter while the device is installed in a user, thus ensuring that the cross-sectional area of the constricted portion is maintained while the device is installed in a user and therefore does not inhibit the flow of urine. As noted above, this is particularly beneficial in the treatment of urinary retention, but is also advantageous in treatment of urinary incontinence to ensure optimal flow when the valve is open. By way of example, the reinforcing material may comprise a mesh or it may comprise a helical coil. A mesh may be formed from two helical coils wound with opposite senses (e.g. one clockwise and one anticlockwise). The reinforcing material may be formed integrally with the constricted portion. For example, the reinforcing material may be formed integrally with the wall of the constricted portion by overmoulding. For example, the reinforcing material may be placed into a mould and then the material of the wall (and optionally the rest of the outlet tube) may be moulded over and / or around the reinforcing material.

[0060] Alternatively, reinforcement may be provided by shaping of the outlet tube. For example, the outlet tube may comprise one or more ribs or other projections on its internal surface (i.e. projecting into the flow path). The added material of these projections provides resistance against kinking. The presence of one or more ribs or projections at distinct angular positions around the axis is better than a uniform increase in wall thickness as the ribs or projections take up less area in the flow path, thus allowing a large enough cross-sectional area for the desired flow rate. Ribs may be provided along the full length of the outlet tube (which may be easier for manufacturing) or they may be provided only the region (or regions) which require resistance to kinking, e.g. the constricted section adjacent to the skirt. In some embodiments two or more ribs or projections may be arranged to come into contact with each other under bending motion so as to resist further bending (i.e. resist kinking). It is preferred that any ribs or other projections formed in this way have rounded edges and corners (e.g. edges and corners with a radius to prevent sharp changes of direction in the surface). Rounding the edges and corners smooths the surface and hinders bacterial growth.

[0061] In a set of embodiments, the valve portion comprises a constricted portion which is attached to the outlet tube. The constricted portion of the valve portion may be at least partly positioned within the constricted portion of the outlet tube when the device is assembled. In a set of embodiments, the constricted portion of the valve portion is releasably attached to the outlet tube, the constricted portion of the valve portion being at least partly positioned within the constricted portion of the outlet tube when the outlet tube is attached to the valve section. Thus, the valve section may be sized appropriately for a strong releasable attachment to the outlet tube.

[0062] In a set of embodiments, the device comprises a resilient skirt arranged, in use, to inhibit movement of the device towards the urethra, the resilient skirt being positioned between the fluid inlet and the fluid outlet. The resilient skirt may therefore function as a positioning structure. The resilient skirt may extend laterally from the device and thus contact the bladder wall if the device moves towards the urethra, thereby inhibiting the device from moving further into the urethra. The skirt being resilient may help ensure that it can conform to the shape of the urethral opening when the device is installed, and thus prevent it from digging into the bladder wall and causing damage or discomfort to the user.

[0063] In a set of embodiments, the resilient skirt is positioned substantially adjacent to the fluid inlet. This may ensure that the fluid inlet does not move into the urethra and thus prevent fluid communication between the fluid inlet and urine contained in the bladder, ensuring the device remains functional while it is installed in a user.

[0064] In a set of embodiments, the resilient skirt and the outlet tube are integrally moulded. This may provide a convenient mechanism for manufacturing the device in a manner which ensures the resilient skirt remains attached to the device in the same position when it is installed. In embodiments where the outlet tube is releasably attachable to the valve section and the resilient skirt and the outlet tube are integrally moulded, the skirt may similarly be releasably attachable to the valve section by virtue of its integral moulding with the resilient outlet tube. In a set of embodiments, the resilient skirt is formed at an end of the outlet tube. The resilient skirt may be formed at the opposite end of the outlet tube to the fluid outlet.

[0065] In a set of embodiments, the resilient skirt comprises one or more radially extending ridges. In a set of embodiments, the resilient skirt comprises a plurality of radially extending ridges having a portion of material extending therebetween, each of the radially extending ridges having a greater thickness than the material extending therebetween. The ridges and the material extending therebetween may be integrally moulded and formed from the same material - e.g. silicone. These ridges may provide resiliency to the skirt so as to cause it to return to a non-stressed position after deviating from the non-stressed position due to external forces applied thereto.

[0066] In a set of embodiments, the radially outer ends of the radially extending ridges taper in thickness from their thickest points to the thickness of the material extending therebetween. The upper surfaces of the ridges may also have a rounded profile. Such embodiments may advantageously ensure that the surface of the skirt having the radially extending ridges protruding therefrom has an overall smooth surface without any sharp or angled edges.

[0067] In some embodiments, each of the radially extending ridges has a thickness at its thickest point that is at least 2 times greater than a thickness of the material extending therebetween. In some embodiments, each of the radially extending ridges has a thickness at its thickest point that is up to 10 times greater than a thickness of the material extending therebetween. In some embodiments, the radially extending ridges have a thickness at their thickest points of from 0.1 mm to 2 mm. In some embodiments, the portions of material extending between the radially extending ridges have a thickness of from 0.05 mm to 0.5 mm. Such thickness ratios and ranges may provide a good balance of flexibility and resiliency for the skirt.

[0068] In a set of embodiments, when in a non-stressed position, the resilient skirt comprises a first face which is substantially smooth and a second face comprising the radially extending ridges protruding therefrom, the first face facing away from the fluid inlet and the second face facing towards the fluid inlet. In other words, the radially extending ridges may only be present on one face of the resilient skirt. This may provide the skirt with the required levels of resiliency though inclusion of the ridges while also ensuring that the face which may contact the bladder wall (i.e. the first face facing away from the fluid inlet) is smooth so as to minimise the risk of urine getting trapped underneath the skirt. It may also help improve comfort by ensuring that the ridges do not protrude into the bladder wall.

[0069] In a set of embodiments, the resilient skirt, when in a non-stressed position, is substantially planar. The resilient skirt may form a substantially disc-like shape when in a non-stressed position. Such embodiments may enable the skirt to function as a positioning structure as described above.

[0070] In a set of embodiments, the resilient skirt permits folding so as to conform to the shape of the exterior surface of the outlet tube, and the resilient skirt permits folding so as to conform to the shape of the exterior surface of the valve portion. In such embodiments, the resilient skirt may permit folding in two different directions - towards the casing, and towards the fluid outlet. This may advantageously allow the skirt to collapse around the device when sufficient force is applied thereto so as to enable easy insertion and extraction of the device. In a set of embodiments, the resilient skirt permits folding so as to wrap around the exterior surface of the outlet tube, and the resilient skirt permits folding so as to wrap around the exterior surface of the valve portion. In a set of embodiments, the resilient skirt permits folding into a substantially tube-shaped configuration wrapping around the outlet tube, and the resilient skirt permits folding into a substantially tube-shaped configuration wrapping around the valve portion. The resilient skirt may be arranged to fold into the substantially tube-shaped configuration wrapping around the outlet tube during insertion of the device into a urethra, and to fold into the substantially tube-shaped configuration wrapping around the valve portion during removal of the device through the urethra.

[0071] In a set of embodiments, the resilient skirt is arranged, in use, to permit folding into a substantially truncated-cone-shaped configuration located at least partially in a urethral opening of a bladder, with the base of the truncated-cone shape facing towards the bladder. This may enable the skirt to conform to the shape of the urethral opening of the bladder and thus allow the device to sit comfortably within the urethral opening, with the fluid inlet located as close to the urethral opening as possible without being obstructed by it, or by the skirt.

[0072] In a set of embodiments, the radially extending ridges have a notch at their radially inner ends. The radially inner ends of the radially extending ridges may taper in thickness from their thickest points to the thickness of the material extending therebetween. The angle of the taper may be selected so as to define the cone angle of the truncated-cone shape. The angle of the taper may be selected so as to match the cone shape of the urethral neck. In some embodiments the angle of the taper may be in a range having a lower end point of 20 degrees, 30 degrees or 40 degrees and having an upper end point of 40 degrees, 50 degrees or 60 degrees, such as 20 to 40 degrees, 20 to 50 degrees, 20 to 60 degrees, 30 to 40 degrees, 30 to 50 degrees, 30 to 60 degrees, 40 to 50 degrees or 40 to 60 degrees. Each of these angles is measured with respect to the axis of the device (i.e. such that an angle of 20 degrees is a narrow notch allowing a lower range of motion and an angle of 60 degrees is a larger notch allowing a greater range of motion).

[0073] The angle of the taper defines a first range of folding of the skirt between the nonstressed configuration of the skirt and the position in which the radially inner taper of the ridges contacts the outer wall of the valve portion. In this first range of folding, the skirt has a first, low stiffness. Folding up to this point requires only deformation of the thin material between the ridges and the thin material forming the hinge at the base of the radially inner taper. Folding beyond this point, i.e. into a second range of folding requires some deformation of the ridges and thus provides a second, higher stiffness (high relative to the first stiffness, but still being a low enough stiffness that the skirt can fold up completely to wrap around the valve portion during extraction). The first range of folding with the low stiffness allows the skirt to deform easily and settle in the urethral neck where it can closely conform to the shape of the urethral neck and provide a good seal. The higher stiffness in the second range of folding resists further folding of the skirt so that it does not readily collapse, but instead defines the optimal position of the device within the bladder with the urine inlet positioned to facilitate complete voiding of the bladder.

[0074] In a set of embodiments, the device may comprise an inlet protector extending outwardly from the device from a position between the fluid inlet and the fluid outlet. The resilient skirt may be or may act as the inlet protector. In other embodiments, the inlet protector may not be resilient but may be a skirt.

[0075] The inlet protector functions to protect the fluid inlet by separating it from contact with the bladder wall and thus keeping it out of contact with tissue. Problems can arise when the process of evacuating the bladder causes tissue from the bladder wall to be sucked into the fluid inlet. There are a number of issues with this. For example, the tissue can get stuck to the device which blocks the fluid inlet. The tissue can also be damaged by this process, resulting in bleeding. Also, small pieces of tissue can lodge within the device causing blockage and biofouling. This reduces the available size of the fluid inlet which reduces the flow rate. A high flow rate is better as it flushes any fouling or urine deposits (e.g. due to crystallisation over time of residual urine) out of the device. A lower flow rate is less effective at such flushing so that deposits build up quicker and present a greater infection risk, thus reducing the time that the device can remain in place. As the inlet protector extends outwardly from the device from a position between the fluid inlet and the fluid outlet (i.e. so that the fluid inlet is held more towards the bladder, away from the urethra and the urethral neck) it keeps the fluid inlet slightly separated from the bladder wall tissue and thus ensures a good flushing flow rate with reduced risk of fouling.

[0076] In a set of embodiments, the inlet protector is foldable such that it axially overlaps the fluid inlet. Here, axially should be interpreted to mean in a direction parallel to a longitudinal axis of the device. In other words, the inlet protector is foldable such that at least one plane can be drawn perpendicular to the longitudinal axis of the device that intercepts both the fluid inlet and the inlet protector. The inlet protector may be foldable such that it axially overlaps the entirety of the inlet, or it may axially overlap only a portion of the fluid inlet. In some embodiments there may also be overlap in the circumferential direction (either full or partial circumferential overlap) between the inlet protector and the fluid inlet. However, in other embodiments there could be axial overlap, but no circumferential overlap, e.g. where the inlet protector comprises flaps that fold up circumferentially adjacent to the fluid inlet. Where the fluid inlet comprises a plurality of holes in a side wall of the device, the inlet protector may axially overlap at least a hole located axially closest to the fluid outlet. In a set of embodiments, the skirt or inlet protector reduces in thickness between its radially inner edge and its radially outer edge. The reduction in thickness may be effected by a smooth taper or a stepped taper. In the case of a smooth taper, the thickness may taper from between an inner radius and an outer radius. In some examples the inner radius may be the skirt’ s / inlet protector’s radially inner edge. In some embodiments the outer radius may be the skirt’ s / inlet protector’s radially outer edge. In other embodiments the smooth tapered section may extend across only a part (e.g. a middle part) of the skirt / inlet protector. In the case of a stepped taper, the skirt / inlet protector may include one or more step reductions in thickness. These step reductions may each be at a given radius (although in other examples they need not necessarily be symmetrical). A stepped taper may be easier to manufacture. The taper (stepped or smooth) is arranged such that the skirt / inlet protector gets thinner towards its radially outer edge (i.e. it gets thinner as the radius increases). This reduces the volume of material in the outer parts of the skirt / inlet protector. The outer parts of the skirt / inlet protector experience more folding (e.g. overlapping) when it is folded up against the outlet tube or valve section and therefore when the outer parts of the skirt / inlet protector are thinner, these folded sections have a reduced thickness. Thus, in the folded state, the device overall has a smaller diameter which is easier and more comfortable to insert and remove through the urethra. The thicker parts of the skirt / inlet protector at the radially inner side provide the required stiffness to ensure that it unfolds when the device is deployed and resists folding up in normal use (e.g. so that the device is located correctly in the urethral neck). Where the skirt / inlet protector has one or more radially extending ridges as discussed above, these may have a uniform thickness (i.e. be non-tapered) so as to provide greater resilience for deploying and maintaining the skirt / inlet protector in its non-stressed configuration. However, in other examples, the (or each) radially extending ridge may also reduce in thickness between its radially inner edge and its radially outward edge, e.g. it may be tapered (smooth or stepped). The tapering of the radially extending ridges may match the tapering of the thinner material between ridges, i.e. the ridges may maintain a consistent increase in thickness relative to the thinner material between ridges.

[0077] In a set of embodiments, at least a portion of the device comprises a magnetic material so as to enable a magnetic extraction device, insertable into a urethra, to releasably attach to the device for extraction of the device through the urethra. This may provide a convenient mechanism for extraction of the device without requiring surgery.

[0078] In a set of embodiments, said portion of the device comprising a magnetic material is located, while the device is in use, in the urethra. In some embodiments, said portion of the device comprising a magnetic material is located at or near to the fluid outlet. This may allow the portion of magnetic material to be more easily accessed by the magnetic extraction device when it is inserted into the urethra.

[0079] Although the skirt provides a degree of sealing in the urethral neck and the constricted portion of the outlet tube may be held tightly by the urethral sphincter muscle, there is still a possibility in some users of leakage past the skirt and bypassing the device. This may occur particularly for example in the case of users with some scar tissue in the region of the sphincter muscle, e.g. as a result of surgery. The scar tissue has a different hardness to the surrounding tissue and can reduce the sealing quality. Thus, in a set of embodiments, a compressible material is provided around at least a portion of the outlet tube. The compressible material may form a compressible tube or jacket around the outlet tube. If the outlet tube comprises a constricted portion, the compressible material may be provided around the constricted portion so that the overall diameter of the device can be kept low, and also as this is an area particularly prone to poor sealing. The compressible material may be provided in a region that overlaps with the skirt when the skirt is folded against the outlet tube (e.g. during insertion of the device). However, due to the compressibility of the compressible material, the skirt can compress the material such that the compressible material does not cause any increase in overall diameter of the device during insertion. The compressible material is ideally very soft so as to compress easily during insertion and not increase the overall resistance or discomfort to the user. The compressible material may be a foam, optionally a memory foam. The softness of the compressible material will allow it to adapt to the form of the particular user’s urethra, e.g. to deform and seal around any areas of scar tissue and thus provide a seal against bypass leakage. The compressible material may be arranged such that it can compress in the radial dimension by a factor of at least 2, at least 3, at least 4, or at least 5. Features of any embodiment described herein may, wherever appropriate, be applied to any other embodiment described herein. Where reference is made to different embodiments or sets of embodiments, it should be understood that these are not necessarily distinct but may overlap.

[0080] BRIEF DESCRIPTION OF THE DRAWINGS

[0081] Certain embodiments of the invention will now be described, by way of example only, and with reference to the accompanying drawings in which:

[0082] Fig. 1 shows a side view of a device for controlling urinary flow in accordance with an embodiment of the invention;

[0083] Figs. 2a & 2b show internal components of a device for controlling urinary flow in accordance with an embodiment of the invention;

[0084] Figs. 3a & 3b show exploded views of a device for controlling urinary flow in accordance with an embodiment of the invention;

[0085] Figs 4a & 4b show a distal end of an outlet tube for a device for controlling urinary flow in accordance with an embodiment of the invention;

[0086] Fig. 5 shows two views of a casing of a device for controlling urinary flow in accordance with an embodiment of the invention;

[0087] Fig. 6 shows a resilient skirt of a device for controlling urinary flow in accordance with an embodiment of the invention;

[0088] Figs. 7a-e show a device for controlling urinary flow in accordance with embodiments of the invention in various positions;

[0089] Figs. 8a and 8b show a clip mechanism and reinforcement material in accordance with embodiments of the invention;

[0090] Fig. 8c shows two possible profiles for a reinforcement structure;

[0091] Figs. 9a-c show a resilient skirt of a device for controlling urinary flow in accordance with embodiments of the invention;

[0092] Figs. 10a and 10b show a compressible jacket of a device for controlling urinary flow in accordance with embodiments of the invention;

[0093] Figs. 11a and 11b show a device adapted for female anatomy;

[0094] Figs. 12a and 12b show an example of an actuator mechanism; and

[0095] Figs. 13a-d and 14a-d show further embodiments of a resilient skirt.

[0096] DETAILED DESCRIPTION OF THE DRAWINGS Fig. 1 shows a side view of a device 100 for controlling urinary flow in accordance with an embodiment of the invention, in a non-stressed position (i.e. where no external forces are applied thereto). The device 100 comprises a fluid inlet 102, a fluid outlet 104, a casing 106 and a resilient outlet tube 108. The casing 106 comprises three sections: a first section 110, a second section 112 and a third section 114. The first section 110 is connected to the second section 112 by a first flexible neck portion 116, and the second section 112 is connected to the third section 114 by a second flexible neck portion 118. Each section is elongate, with the first and second sections 110, 112 having a circular cross-section when viewed along their longitudinal axes so as to form a tube shape, and the third section having a substantially rectangular cross-section, with rounded corners, when viewed along its longitudinal axis. This is described in more detail later with reference to Fig. 5.

[0097] As will be described in more detail later with reference to Figs. 7a-e, the device 100 is insertable into a urethra to be positioned in the urethral opening of a bladder, with a majority of the outlet tube 108 extending away from the urethral opening of the bladder into the urethra, and the casing 106 extending away from the urethral opening of the bladder into the bladder.

[0098] A valve section 120 is rigidly connected to, and partially encased by, the first section 110. This connection is water-tight so no liquid can enter the casing 106 between the first section 110 and the valve section 120. The valve section 120 is also rigidly connected to, and partially encased by, the resilient outlet tube 108. This connection is also water tight. The connection between the valve section 120 and the outlet tube 108 is releasable, e.g. using clips located on the outer surface of the valve section 120 and on the inner surface of the outlet tube 108, so as to allow the outlet tube 108 to be disconnected from the valve section 120. This is shown in more detail in Fig. 3 and a clip mechanism is illustrated in Figs. 8a and 8b which are described in more detail later.

[0099] The resilient outlet tube 108 comprises a resilient skirt 122, a first portion 124 and a second portion 126. The skirt 122 is described in more detail later with reference to Fig. 6. When the resilient outlet tube 108 is in a non-stressed position, as shown in Fig. 1 , the first portion 124 is substantially straight and the second portion 126 is curved. The resilient outlet tube 108 in this embodiment has a substantially circular cross-section. The first portion 124 comprises a constricted portion 128 having a smaller cross-sectional area than the curved second portion 126. The substantially straight first portion 124 also comprises a tapering portion 130 which has a crosssection which tapers from the cross-section of the constricted portion 128 to the larger cross-section of the curved second portion 126 so as to form the shape of a truncated cone. Two holes 132 are provided in the side wall of the resilient outlet tube 108 on opposing sides. These holes 132 are sized to allow a suture or thread or flexible line to be connected to the outlet tube for insertion and / or extraction of the device.

[0100] The curved second portion 126 of the outlet tube 108 curves through an angle of approximately 90° when in a non-stressed position to form an overall J-shape. This shape advantageously aligns closely with the anatomy of the male urethra. As a result, the curved outlet tube 108 functions as a positioning mechanism when the device 100 is installed in a patient, helping to prevent the device from moving towards the bladder or towards the urethra away from the ideal position where the fluid inlet 102 is located close to the urethral opening of the bladder. Since the anatomy of the urethra varies from patient to patient, the outlet tube 108 is manufactured in a number of different sizes (e.g. three, or more), particularly though not exclusively with regard to the length of the substantially straight first portion 124, and the tube of the correct size is selected to match the anatomy of the specific patient. Since the outlet tube 108 is releasably attached to the valve section 120, the same valve section 120 and casing can be used for patients irrespective of their individual anatomy, and only the outlet tube 108 is selected for a particular patient. This advantageously keeps manufacturing costs down while still enabling the device 100 to be used for any male patient. In particular, an appropriate size of outlet tube 108 can be selected at the time of insertion (e.g. at an operation site) and thus can be selected for the specific patient. This allows inspection, measurement and / or analysis of the patient by a professional before selection of the optimal size of outlet tube 108. Once selected, the chosen outlet tube 108 can be attached quickly, e.g. clipped into place.

[0101] The constricted portion 128 also aids positioning. When the device 100 is installed in a user, the constricted portion 128 aligns with the sphincter at the urethral opening of the bladder. The sphincter effectively grips the device 100 at the constricted portion forming a seal therewith. This helps prevent leakage of urine around the device 100, and also helps prevent the device 100 from moving towards the bladder or urethra. The skirt 122 also aids in positioning the device 100, though this is described in more detail later with reference to Figs. 6 and 7a-e.

[0102] The constricted portion 128 in this embodiment comprises reinforcing material integrated into the walls thereof in order to inhibit the constricted portion from significantly bending or kinking during insertion and / or removal from a user, thus improving comfort and reducing risk of damage during insertion / extraction. The reinforcing material further prevents the constricted portion 128 from significantly collapsing under pressure from the urethral sphincter while the device 100 is installed in a user, thus ensuring that the flow path from the fluid inlet 102 to the fluid outlet 104 is not obstructed by such a collapse. The reinforcing material may take the form of a mesh or a helical coil. In some examples, a mesh may be formed from two helical coils; one with a clockwise spiral and the other with an anticlockwise spiral. The reinforcing material may be moulded integrally with the walls, e.g. by overmoulding.

[0103] Alternatively, reinforcement may be provided by shaping of the outlet tube. Two examples of internal shaping are shown in Fig. 8c. Each of these shows four ribs 169 (although any number may be used) on the internal surface of the outlet tube 108, projecting into the flow path. The added material of these projections provides resistance against kinking while not adversely reducing the area of the flow path and thus allowing a desired flow rate to be maintained. The ribs 169 may be provided along the full length of the outlet tube or they may be provided only in the constricted section 128. Although not illustrated in the figure, the ribs 169 will be preferably formed with a radius on each edge 169a and a radius at each corner 169b to prevent sharp changes of direction in the surface. Rounding the edges and corners smooths the surface and hinders bacterial growth.

[0104] The outlet tube 108 may be exchanged for a different type of positioning mechanism in order to allow the device 100 to be used for female patients. Such outlet tubes may have a substantially different overall shape than the outlet tube 108 used for male patients, e.g. being substantially shorter, being substantially straight (i.e. not forming an overall J-shape), and having a radially extending, flexible plate located near to the fluid outlet to prevent the device from slipping further into the bladder (see Figs. 11a and 11b for example).

[0105] The outlet tube 108 may be sufficiently stiff (or may have at least a portion which is sufficiently stiff) that it can maintain its shape and / or form so as to maintain a flow path even in the presence of obstructions. For example, when used for treating urinary retention, the stiffness may be selected to ensure a flow path to bypass a physical obstruction such as a tumour or enlarged prostate or to counter the constriction of a sphincter muscle. Different outlet tubes 108 with different physical characteristics (e.g. different stiffnesses) can be made available to the physician so that an appropriate or optimal outlet tube can be selected for the condition being treated and can be attached to the valve section 120.

[0106] In this embodiment, a plurality of holes 121 are provided in the side wall of the valve section 120 to form the fluid inlet 102. These inlet holes 121 are located between the skirt 122 and the first section 110 of the casing 106. The valve, and other components located inside the casing 106, are described in more detail later with reference to Fig. 2a and 2b.

[0107] The casing 106 is made from a waterproof, biocompatible and corrosion-resistant material - e.g. silicone - and the first section 110 is attached to the valve section 120 so as to form a watertight seal therebetween. One or more further seals may be provided within the valve section 120 and / or the first section 110 in order to prevent liquid entering the casing 110 from the fluid inlet 102. Thus, the casing 106 forms a water-tight cavity in which various components of the device 100 are housed, protected from any surrounding liquid. The casing 106 may be coated with a waterproof coating (e.g. parylene) on the exterior or interior thereof in order to help further ensure that the casing 106 forms a water-tight cavity.

[0108] The flexible neck portions 116, 118 are formed substantially in the shape of an hourglass, and have a smaller cross-sectional perimeter at the waists thereof (when viewed perpendicular to their respective longitudinal axes) than the adjacent sections 110, 112, 114. The flexible neck portions 116, 118 are made from a flexible / resilient material which is waterproof and resistant to corrosion - e.g. silicone. The flexible neck portions 116, 118, in their non-stressed state, cause the casing 106 to have an overall curved shape as illustrated in Fig. 1. In other words, in their non-stressed state, the flexible neck portions 116, 118 cause the longitudinal axes of the respectively connected sections 110, 112, 114 to be held at an angle relative to each other. In this embodiment, each flexible neck portion 116, 118 causes the respective sections 110, 112, 114 connected thereto to be held at a relative angle of about 30° when the flexible necks are in their non-stressed position.

[0109] In this embodiment, the flexible neck portions 116, 118 are hollow in order to allow e.g. wires to extend therethrough from one section to another. This is described in more detail later with reference to Figs. 2a and 2b. The sections 110, 112, 114 in this embodiment are made from the same material as the flexible neck portions 116, 118, and moulded integrally therewith. The sections 110, 112, 114 are made from silicone with a greater hardness rating and / or with thicker walls then the flexible neck portions 116, 118, such that the sections 110, 112, 114 have a higher rigidity than the flexible neck portions 116, 118. This may help provide increased protection to any components housed inside the sections 110, 112, 114. The flexible neck portions 116, 118 effectively function as bendable and rotatable joints which allow the relative angles and rotations of the respective sections 110, 112, 114 connected thereto to deviate from the non-stressed positions of the flexible necks 116, 118 when force is applied thereto, as is described in more detail below with reference to Figs. 7a-e.

[0110] After one or more components and wires are inserted into the casing 106 (or the casing 106 is formed around one or more components), it is filled with a soft material that permits bending. This reduces or eliminates empty space within the sections 110, 112, 114 of the casing and the flexible neck portions 116, 118, while still allowing the flexible neck portions 116, 118 to have the required range of motion. This advantageously reduces or eliminates the presence of gas within the casing 106, thereby reducing the risk or gas entering a user from the casing 106 e.g. due to gas-permeability at one or more parts of the casing 106. As an alternative, instead of adding soft material after components have been inserted into the casing, the components and the soft material may be arranged first and the casing 106 may be overmoulded over the components and the soft material. Figs. 2a and 2b show the internals of the casing 106 in more detail. Fig. 2a shows the internals of the first section 110 of the casing 106. It can be seen that the valve section 120 extends into the first section 110 of the casing 106. A valve 123 is provided inside of the valve section 110, located between the fluid inlet 102 and the fluid outlet 104, which is operable to allow fluid to flow from the inlet 102 to the outlet 104 when in an open position, and to prevent fluid from flowing from the inlet 102 to the outlet 104 when in a closed position. In Fig. 2a the valve 123 is shown in the open position. Any suitable valve may be provided for this purpose, though in this particular embodiment the valve 123 comprises a valve head 125 and a valve seat 127, the valve head 125 moveable into and out of contact with the valve seat 127 to provide the closed and open positions respectively. An actuator 129 for the valve is located inside of the first section 110. In this particular embodiment the actuator 129 is a moveable piston extending into the first section 110, the piston being attached to the valve head 125 thereby enabling the valve head 125 to be moved linearly between open and closed positions. In this embodiment, the actuator 129 comprises a permanent magnet moveable by action of electromagnetic coils 131 surrounding the piston 129.

[0111] As shown in Fig. 2b, the actuator 129 located inside the first section 110 is operably connected to and controlled by an electronic control circuit 139 located inside the second section 112. One or more wires 133 extend through the first flexible neck portion 116 for this purpose. An antenna 141 is also provided within the second section 112 which enables wireless communication to an external communications device (not shown) e.g. using a radio protocol such as Bluetooth™, Wi-Fi™, or any other suitable protocol. This allows the valve inside the valve portion to be controlled by the user of the device 100 using this external communications device. The antenna 141 may partially surround the electronic control circuitry 139 in order to ensure the strong signal reception from any location around the device 100, as shown in Fig. 2b. However, in other embodiments the antenna 141 may be located differently, e.g. adjacent to the electronic control circuitry 139. The device of Fig. 2b has a different version of the outlet tube 108’ to that shown in Fig. 1 , though it shares many features in common. The external communications device may be a dedicated device for this purpose, or it may be e.g. a mobile phone, smart watch, etc. which may help negate the need for the user to carry a dedicated device for controlling the device 100. Where the external communications device is a smartphone, additional information may be transmitted thereto by the device 100 for monitoring thereof, as described previously.

[0112] A battery 143, or other energy storage device (e.g. a capacitor), is located inside the third section 114. This battery 143 provides the power required to operate the electronic control circuitry 139 within the second section 112, as well as the actuator 129 inside the first section 110. One or more wires 133 extend through the second flexible neck portion 118 for this purpose.

[0113] The casing 106 provides a convenient location for the actuator 129, energy storage device 143, control circuitry 139, wires 133, antenna 141 , etc. to be held. Since the casing 106 is located on the opposite side of the fluid inlet 102 to the fluid outlet 104, these components are advantageously located outside of the flow path between the fluid inlet 102 and the fluid outlet 104, ensuring that these components do not obstruct the flow path. This advantageously allows the cross-sectional area of the conduit between the fluid inlet 102 and the fluid outlet 104 to be maximised, thus allowing a high flow rate (i.e. a relatively normal urination flow rate) to be achieved. This provides an improved quality of life for the user as the urination process is much closer to normal.

[0114] Fig. 3a shows an exploded view of the device 100, with the casing 106, outlet tube 108” and valve section 120 separated from one another, showing its construction in more detail. These three components of the device 100 are manufactured individually and assembled to form the complete device 100. The valve section 120 comprises a main body 134 for insertion into the first section 110 of the casing 106. This may be sealed using adhesive, clips, or any other known method. The fluid inlet holes 121 are located at the lower part of the main body 134. The actuator 129 is also at least partially contained within the main body 134. The valve section 120 also comprises a constricted portion 136 for insertion into the constricted section 128 of the outlet tube 108”, and for releasable attachment thereto - e.g. using a friction fit, clips, etc. One example of a releasable attachment mechanism is illustrated in Figs. 8a and 8b which are described in more detail later.

[0115] Fig. 3b shows a semi-exploded view of the device showing the valve section 120 when it is inserted into the first section 110 of the casing 106, and attached thereto. This is the state in which the device 100 will typically be shipped, with a number of different sized outlet tubes 108” for selection by a physician in dependence on the intended user of the device as described previously.

[0116] The outlet tube 108” shown in Figs. 3a and 3b is a different version to that shown in Figs. 1 and 2b, though it shares many features in common. In these embodiments the outlet tube 108” comprises a tapering portion 135 at the end thereof closest to the fluid outlet 104. This tapering portion 135 reduces pressure applied by the fluid outlet 104 to the urethral wall during removal of the device 100 from a user, thus improving comfort and reducing risk of damage during extraction. The outlet tube 108” further comprises a reinforcing ring (not shown in Figs. 3a and 3b), which is described in more detail below with reference to Figs. 4a and 4b.

[0117] Fig. 4a shows the outlet tube 108” in more detail. The outlet tube 108” comprises a reinforcing ring 137 embedded in the wall of the outlet tube 108”, near to the fluid outlet 104. The reinforcing ring 137 in this embodiment is located at the point along the outlet tube 108” at which the tapering portion 135 is at its widest.

[0118] The reinforcing ring 137 is formed from a material that permits lateral compression so as to compress the end of the outlet tube 108”, but resists expansion when force is applied outwardly from within the ring 137. In this embodiment the reinforcing ring 137 is formed from ePTFE, though in other embodiments it may be formed from other appropriate materials e.g. nylon, polyester, nitinol, steel, etc. The reinforcing ring 137 provides a level of structural rigidity to the end of the outlet tube 108” when an outward force is applied thereto from inside it, since the remaining material of the outlet tube 108” is more flexible as set out in more detail below with reference to Figs. 7a-e. This means that an extraction tool having an expanding member located at an end thereof can be inserted into the outlet tube 108” and expanded in order to remove the device 100 from the user through the urethra. The reinforcing ring 137 provides a sufficiently high reaction force to the expanding member of the extraction tool in order to ensure that the friction between the tool and the outlet tube 108” is sufficient to allow removal of the device 100.

[0119] Fig. 4b shows a cross-section of the outlet tube 108”. It can be seen that in this embodiment the reinforcing ring 137 has a substantially rectangular cross section. However, in other embodiments the reinforcing ring 137 may have any appropriate shape, e.g. having a substantially circular cross-section. The reinforcing ring 137 may have an O-ring shape. In other embodiments the reinforcing ring 137 may be formed from a thread with high tensile strength encircling the flow path within the outlet tube 108” and embedded within the wall of the outlet tube 108”. ePTFE may provide a suitable material for the embodiment shown in Fig. 4b where the reinforcing ring 137 forms the shape of a sheath, whereas in other embodiments where the reinforcing ring 137 has e.g. a circular cross-section, other materials e.g. nylon, polyester, nitinol and steel may be more suitable.

[0120] Fig. 5 shows the casing 106 from different angles. It can be seen from Fig. 5 that the first and second sections 110, 112 are formed as elongated cylindrical tubes (i.e. have substantially circular cross-sections when viewed along their longitudinal axes). The third section 114, on the other hand, has a substantially rectangular cross-section, with rounded corners, when viewed along its longitudinal axis, and the end 138 of the third section 114 furthest from the second flexible neck portion 118 is rounded.

[0121] This shape for the third section 114 is advantageous for a number of reasons. Firstly, this shape aligns more closely with the cross-section of the urinary meatus in most patients. Since the third section is the first portion of the device to enter the urinary meatus when the device 100 is inserted into a patent, this advantageously improves the ease of insertion, since less force is exerted on the urinary meatus at the leading end of the device 100 during installation. Secondly, the shape of the third section 114 aligns more closely with the types of commercially available batteries suitable for use in the device 100, which typically have a substantially rectangular cross-section. This shape therefore advantageously helps decrease the cost of manufacture since custom batteries may not be required for the device 100, while removing dead-space from the third section 114 thus allowing the cross- sectional area of the third section 100 to be kept low, thereby providing improved ease of insertion and removal through the urethra.

[0122] Fig. 6 shows the skirt 122 in more detail, shown in its non-stressed position. The skirt 122, in its non-stressed position, is substantially planar, and forms an overall disc-like shape. It comprises four radially extending ridges 140 protruding from a first face 142 thereof (facing towards the fluid inlet 102 of the device 100 when the outlet tube is attached to the valve section 120). The second, opposite face 144 is substantially smooth, and is designed for contact with the bladder wall when the device 100 is installed in a user. Extending between the four radially extending ridges 140 is a portion of comparatively thin material 146.

[0123] The four radially extending ridges 140 provide the skirt 122 with resiliency - i.e. they ensure that the skirt 122 returns to the non-stressed position shown in Fig. 6 after being deformed away therefrom though application of an external force. The portions of comparatively thin material 146, provide the skirt 122 with flexibility, and are able to fold in on themselves in certain circumstances. This is shown in more detail in Figs. 7a-e. The skirt 122 in this embodiment is formed as a single integrally moulded piece, which is also integrally moulded with the outlet tube 108, connected thereto at the constricted portion 128 thereof, and formed from silicone. The radially outer ends of the radially extending ridges 140 taper in thickness from their thickest points to the level of the thin material 146 extending therebetween so as to form an overall smooth surface without any sharp or angled edges. The upper surfaces of the ridges 140 (the surface furthest from the thin material 146) also has a rounded profile without sharp edges.

[0124] In this embodiment, the radially extending ridges 140 are about five times thicker (at their thickest points) than the portions of comparatively thin material 146 extending therebetween - with the ridges 140 being approximately 1 mm thick and the material 146 being approximately 0.2 mm thick. This is not limiting, however. Different thicknesses and / or ratios could be applied in other embodiments.

[0125] Figs. 7a-e show various perspective views of the device 100 illustrating how it can deform in various ways. Each of these figures shows many of the same parts of the device 100 as shown in Figs. 1-6, though the provision of reference signs for all features of the device 100 in the figures is omitted here for ease of understanding.

[0126] Fig. 7a shows how the flexible neck portion 116 permits bending around an axis, in both directions in order to increase / decrease the relative angles of the adjacent sections 110, 112 connected thereto. In this embodiment, each flexible neck portion 116 permits bending by up to ±45° around this axis from its non-stressed position. As noted earlier, in the non-stressed position, the sections 110, 112 have an angle of 30° in this embodiment. Therefore the range of motion extends to a range of -15° to 75° around the axis. This allows the casing 106 to flex or bend when it comes into contact with the bladder wall, thereby increasing comfort for the user and decreasing health risks. Fig. 7a also shows the fluid inlet 102 in detail as a plurality of holes formed in the side wall of the valve section 120.

[0127] Fig. 7b shows how the flexible neck portions 116, 118 permit bending around other axes. It can be seen that the flexible neck portions 116, 118 permit bending around any axis perpendicular to a longitudinal axis of an adjacent section 110, 112, 114 of the casing 106, to give the casing 106 a full range of motion. Each flexible neck 116, 118 in this embodiment permits bending by up to ±45° around any axis from the non-stressed position thereof. Fig. 7b also shows how the skirt 122 can fold towards the outlet tube 108’, and towards the valve section 120. Fig. 7b also shows how the curved section 126 of the resilient outlet tube 108’ can bend in order to substantially straighten the outlet tube 108’. While the outlet tube 108’ shown in Figs. 7a-e is the same version as that shown in Fig. 2b, and therefore does not have some features which are present in the versions 108, 108” of Figs. 1 and 3a- b, it will be appreciated that the bending and straightening functionality of these outlet tubes 108, 108” is the same as that shown in Figs. 7a-e for this version of the outlet tube 108’.

[0128] Fig. 7c shows the device 100 in a substantially straight configuration, where the casing 100 has been substantially straightened by virtue of the flexible neck portions 116, 118, and the curved portion 126 of the resilient outlet tube 106 has been substantially straightened. The device 100 substantially adopts this configuration whilst the device is being inserted into a urethra, although it will bend in order to pass around any bends in the urethra as will be appreciated by those skilled in the art.

[0129] Furthermore, Fig. 7c shows the skirt 122 in a folded configuration wrapping around the outlet tube 108’. The skirt 122 adopts this configuration while the device is being inserted into a urethra. This allows the device 100 to have an overall small cross- sectional area, and avoids the skirt 122 from inhibiting insertion of the device 100 into a user.

[0130] Fig. 7d shows the device 100 where the outlet tube 108’ is in a substantially nonstressed configuration, and the skirt 122 folded into a substantially truncated-cone- shaped configuration. This is the natural state of the device 100 whilst it is installed in a male user, when held in the optimal position where the casing 106 is located within the bladder, the outlet tube 108’ is located in the urethra, and the skirt 122 is located at least partially in the urethral opening and conforming to the shape thereof. In the embodiments shown in Figs. 7a-e, the outlet tube 108’ does not include a constricted portion 128 since it shows a different version of the device 100, though it will be appreciated that if it did it would be located adjacent to the skirt 122 and thus gripped by the urethral sphincter when the device is installed in a user as shown in Fig. 7d, as described previously.

[0131] Fig. 7e shows the device 100 in a substantially straight configuration like Fig. 7c, except that it shows the configuration of the device 100 during extraction from a user. The overall configuration is the same as that shown in Fig. 7c, except that the skirt 122 is in a folded configuration wrapping around the valve portion 120, rather than around the outlet tube 108’.

[0132] Fig. 7e also illustrates how the flexible neck portions 116, 118 permit a relative twisting motion of the respective sections 110, 112, 114 connected thereto. In this embodiment, the flexible neck portions 116, 118 permit relative twisting of the adjacent sections 110, 112, 114 by up to ±90° from the non-stressed positions thereof.

[0133] Fig. 8a shows a cross-section of a J-shaped outlet tube 108’” which is similar to those already discussed above. However, the outlet tube 108’” illustrates two additional features (which may also be applied to the other outlet tubes 108, 108’, 108” discussed above, either both or only one of the additional features). Firstly, the outlet tube 108”’ has reinforcing material 150 embedded therein in the region of the constricted portion 128. The reinforcing material 150 serves to resist kinking of the outlet tube 108’” in the region where its wall is thinnest (i.e. in the constricted portion 128) while also providing resistance against collapse from the surrounding sphincter muscle when the outlet tube 108’” is installed in a user. The reinforcing material 150 is formed as a mesh from two helical wires. One helical wire is wound in a clockwise sense and the other helical wire is wound in an anticlockwise sense.

[0134] Figs. 8a and 8b also show a female part 160 of a releasable attachment mechanism in the form of a clip mechanism which is mounted in the upper end of the outlet tube 108’” adjacent to the skirt 122 and is arranged to receive the constricted portion 136 of the valve section 134. The male part 162 of the clip mechanism comprises a flange 164 formed on the end of the valve section 134.

[0135] The female part 160 comprises a cylinder embedded within the outlet tube 108’” and having a plurality of resilient tongues 166 each of which bends radially inwardly when in its non-stressed position. However, each tongue 166 can be pressed radially outwardly, e.g. by the flange 164 passing through the cylinder of the female part 160. Once the flange 164 has passed the bottom of the tongues 166, they snap back into their non-stressed position (or close to it - they may be in contact with the outer wall of the valve section 134) above the flange, thus holding the flange securely beneath the tongues 166. The upper end of the flange 164 (the proximal end) forms a hook surface 167 which engages with a shoulder surface 168 on the bottom (distal side) of the tongues 166. The engagement of these surfaces 167, 168 hinders separation of the valve section 134 from the outlet tube 108’”, thus ensuring that the two parts are held securely together in use.

[0136] Figs. 9a-c show a resilient skirt 122’ similar to that shown in Fig. 6. Fig. 9a is a plan view, Fig. 9b is a cross-section through the line A-A of Fig. 9a and Fig. 9c is a perspective view. As with the skirt 122 of Fig. 6, the skirt 122’ is shown in its nonstressed position and it has four radially extending ridges 140 protruding from a first face 142. The opposite face 144 is substantially smooth. Extending between the four radially extending ridges 140 is a portion of comparatively thin material 146. The difference between the skirt 122 of Fig. 6 and the skirt 122’ of Figs. 9a-c is that the radially extending ridges 140 of the skirt 122’ each have a notch 170 at their radially inner ends. The notch 170 is formed from a tapered surface 172 that tapers from the thickest part of the ridge 140 down to the thinnest part (which may be the same thickness as the portion 146, although this is not essential). The notch 170 acts like a hinge. The reduced thickness of the skirt 122’ in this area makes it more flexible and allows easier folding within a range of folding defined be the angle of the taper 172. The angle of the taper 172 is chosen such that when the tapered surface 172 abuts the outside of the valve portion of the device, the skirt 122’ forms a truncated cone shape as shown in Fig. 7d, but with a particular cone angle defined by the taper angle. This angle may be designed to match the taper that is typically found in the urethral neck. This allows the skirt 122’ to fold readily into this position inside the bladder, but the contact of the tapered surface 172 with the valve portion resists further folding such that it can hold this form and retain its position within the bladder. Further folding of the skirt 122’ is possible when sufficient force is applied, e.g. to remove the device back through the urethra. Under such force, the skirt 122’ folds into a second range of folding in which the ridges 140 are deformed and the skirt wraps around the outside of the valve portion of the device. It will be appreciated that the notches 170 of Figs. 9a-c may be applied to the skirt 122 of any other embodiment.

[0137] Figs. 10a and 10b show another feature that may be included in any of the other embodiments described here. Fig. 10a is a side view and Fig. 10b is a crosssection of an outlet tube 108”” which features a jacket 180 of compressible material around the constricted portion 128. The jacket 180 is formed from a very soft material, such as foam, that is able to compress to a high degree (e.g. its thickness can be compressed by a factor of at least three). The jacket 180 can thus easily compress during installation and removal, but will also expand around the outlet tube 108’” to conform to the shape of the urethra. As the jacket 180 in this embodiment is formed around the constricted portion 128 the jacket 180 will conform to the inside of the urethra in the region of the sphincter muscle. This area can be prone to scarring after surgery which is a common cause of leakage due to the different textures of the scar tissue and healthy tissue. In particular, scar tissue is harder and less compressible. The jacket 180 thus provides an additional seal that can avoid bypass leakage of any urine that manages to pass the skirt 122 and the fluid inlet holes 121.

[0138] Figs. 11a and 11b show a device 100b adapted for female anatomy (with Fig. 11b showing the device 100b in situ within a female urethra and bladder). The device 100b operates in substantially the same way as has been described above. For example, the casing 106 comprises the first section 110, second section 112, third section 114, first flexible neck portion 116, second flexible neck portion 118 and valve section 120. The device has a fluid inlet 102 (with fluid inlet holes 121), a fluid outlet 104 and a resilient skirt portion 122 located between the fluid inlet 102 and the fluid outlet 104. These parts of the device 100b may be the same as is described above. In addition, although not shown in Figs. 11a and 11b, it will be appreciated that other features of the device described above may also apply to the device 100b. For example, the device 100b may include the constricted portion 128 and tapering portion 130.

[0139] The device 100b differs from the device 100 of Fig. 1 in that the outlet tube 108 is straight (i.e. it does not include a curved section 126 as shown in Fig.1). This matches the straighter urethra of a typical female anatomy. In some embodiments the outlet tube 108 on its own may provide enough resistance (e.g. through friction with the urethra) to inhibit movement of the device towards the bladder. However, in order to improve the positioning of the device and to inhibit movement of the device 100b towards the bladder, the embodiment shown in Figs. 11a and 11b includes a retainer 190. The retainer 190 is positioned adjacent to the fluid outlet 104 and extends perpendicularly away from the outlet tube 108. In this embodiment, the retainer 190 has a plate structure. The plate structure may be flat, but in this embodiment it curves slightly away from the outlet tube 108 for improved comfort.

[0140] Figs. 12a and 12b show an example of an actuator 129b. The actuator 129b shown here is an alternative to the mechanism shown in Fig. 2a and comprises a valve 123 which includes a valve head 125 which is moveable into and out of contact with a valve seat 127 to provide the closed and open positions of the valve 123. Fig.

[0141] 12a shows the valve 123 in the closed position and Fig. 12b shows the valve 123 in the open position. The actuator 129b is located inside the first section 110. The actuator 129b is located within a hermetically sealed compartment 200. The actuator 129b is thus sealed against contact with urine and is sealed against any ingress or egress of liquid or gas. The actuator 129b is therefore completely isolated from the valve 123. As the actuator 129b is isolated from the body, it does not need to be sterilized to the same degree as other parts of the device 100.

[0142] The actuator 129b is arranged to move the valve 123 using magnetic forces. The actuator 129b comprises two magnets 202 which can be moved between a first configuration (for the closed position shown in Fig. 12a) and a second configuration (for the open position shown in Fig. 12b). The valve head 125 also comprises two magnets 204 which are in a fixed orientation. In the first configuration, the magnets 202 of the actuator 129b repel the magnets 204 of the valve head 125 and thus bias the valve head 125 into the closed position in which it seals against the valve seat 127. In the second configuration, the magnets 202 of the actuator 129b attract the magnets 204 of the valve head 125 and thus bias the valve head 125 into the open position in which it permits fluid flow through the inlet holes 121 and into the outlet tube 108.

[0143] The movable actuator magnets 202 are rotatable between the first and second configurations. The rotation in this example is around an axis perpendicular to the direction of attraction / repulsion (perpendicular to the movement direction of the valve head 125) such that the rotation changes the polarity of the pole of the magnets 202 that faces the valve head 125, thereby changing the force on the fixed magnets 204 between attraction and repulsion. The actuator 129b can be configured to rotate the magnets by a motor or by a solenoid for example.

[0144] It will be appreciated that many other configurations of the actuator 129b are possible while keeping the actuator 129b hermetically sealed within the compartment 200. For example, the number of magnets may be varied (one magnet, three magnets, four magnets, etc.) and the polarities of the magnets may be changed. The motion of the actuator 129b that induces movement of the valve head 125 may also be achieved in different ways, e.g. by linear movement of magnets 202 or a different axis of rotational movement, or by using electromagnets. Figs. 13a-d show further embodiments of a resilient skirt 122. The skirt 122 also acts as an inlet protector that can fold over the fluid inlet 102 during withdrawal of the device 100 through the urethra, protecting the tissue in the urethra from any sharper edges, e.g. of the fluid inlet holes 121. Fig. 13a is a section view, Fig. 13b is a perspective view showing the section of Fig. 13a. Fig. 13c is a plan view and Fig. 13d is a perspective view of the whole skirt 122. The skirt 122 in this example has five radially extending ridges 140, with a comparatively thinner web of material 146 extending between the ridges 140. As can be seen in Fig. 13a, the skirt has a tapered section 220 which reduces in thickness between its radially inner edge 221 and its radially outer edge 222. The reduction in thickness is achieved via a smooth taper from the skirt’s radially inner edge 221 to the skirt’s radially outer edge. The taper reduces the volume of material in the outer parts of the skirt. The outer parts of the skirt experience more folding (e.g. overlapping) when the skirt is folded up against the outlet tube (as shown in Fig. 7c) or valve section (as shown in Fig. 7e). For example, to reduce the outer circumference of the skirt down to the outer circumference of the outlet tube, the skirt must become folded over itself. As the wider parts of the skirt (with the greatest radius) are thinner, these folded sections have a reduced thickness and the overlaps (whether these are overlaps just of the thin webbing part with itself or overlaps of the webbing with ridges) are correspondingly thinner. Thus, in the folded state, the device overall has a smaller diameter which is easier and more comfortable to insert and remove through the urethra. The thicker parts of the skirt at the radially inner side provide the required stiffness to ensure that the skirt unfolds when the device is deployed and resists folding up in normal use (e.g. so that the device located correctly in the urethral neck). As shown in Figs. 13a-d, the five radially extending ridges 140 are also tapered so that they reduce in thickness between the radially inner edge 221 and radially outward edge 222. The tapering of the radially extending ridges 140 matches the tapering of the thinner web 146 between ridges 140, i.e. the ridges 140 always have the same height above the thinner material 146.

[0145] Figs. 14a-d are similar to Figs. 13a-d, but instead of a smooth taper, the skirt 122, which again also acts as an inlet protector, has a stepped taper. The stepped tapered section 230 in this embodiment comprises three sections of different thicknesses 230a, 230b, 230c and thus the skirt 122 includes two step reductions in thickness between these three sections. Each step reductions takes place at a particular radius so that each of the three sections 230a, 230b, 230c is a ring of constant thickness. As can be seen in Fig. 14a, the five radially extending ridges 140 are also stepped down in thickness in the same manner (and with the step reductions taking place at the same radii as for the thinner material 146).

[0146] It will be appreciated that, although the tapering of Figs. 13 and 14 is shown in isolation, these features can be combined with the other features described elsewhere and in relation to the other figures.

[0147] It will be appreciated by those skilled in the art that the invention has been illustrated by describing one or more specific embodiments thereof, but is not limited to these embodiments; many variations and modifications are possible, within the scope of the accompanying claims.

[0148] Certain specific embodiments of the invention will now be set out by way of example:

[0149] Embodiment 1. A device for controlling urinary flow, comprising: a fluid inlet; a fluid outlet; a valve movable between an open position in which fluid can flow from the fluid inlet to the fluid outlet and a closed position in which fluid flow is blocked between the fluid inlet and the fluid outlet; an actuator operable to move the valve between the open position and the closed position; and a casing positioned on a first side of the fluid inlet, the casing comprising a first section resiliently connected to a second section by a first flexible neck portion, the first and second sections each having a higher rigidity than the first flexible neck portion; wherein the fluid outlet is positioned on a second, opposite side of the fluid inlet.

[0150] Embodiment 2. The device as set out in embodiment 1 , wherein the device is insertable into a urethra and arranged such that, in use, the casing is located in a bladder. Embodiment 3. The device as set out in embodiment 1 or 2, wherein each section of the casing is elongate.

[0151] Embodiment 4. The device as set out in any preceding embodiment, wherein each section of the casing is substantially rigid.

[0152] Embodiment 5. The device as set out in any preceding embodiment, wherein the casing further comprises a third section resiliently connected to the second section by a second flexible neck portion.

[0153] Embodiment 6. The device as set out in any preceding embodiment, wherein the casing forms an overall curved shape when the or each flexible neck portion is in a non-stressed position.

[0154] Embodiment 7. The device as set out in any preceding embodiment, wherein each section of the casing is positioned at an angle relative to the adjacent section(s) when the or each flexible neck portion is in a non-stressed position.

[0155] Embodiment 8. The device as set out in any preceding embodiment, wherein the or each flexible neck portion permits bending around at least one axis, preferably around at least two axes, preferably around any axis perpendicular to a longitudinal axis of a respective sections connected thereto.

[0156] Embodiment 9. The device as set out in embodiment 8, wherein the or each flexible neck portion permits bending around each axis by up to at least ±45° from a non-stressed position of said flexible neck portion.

[0157] Embodiment 10. The device as set out in any preceding embodiment, wherein the or each flexible neck portion permits a relative twisting motion between the respective sections connected thereto.

[0158] Embodiment 11. The device as set out in any preceding embodiment, wherein the or each flexible neck portion permits a relative twisting motion between the respective sections connected thereto by up to ±30°, ±45°, ±60° or ±90° from a nonstressed position of said flexible neck portion.

[0159] Embodiment 12. The device as set out in any preceding embodiment, wherein the or each flexible neck portion has a minimum cross-sectional area that is smaller than a minimum cross-sectional area of a respective section of the casing connected thereto.

[0160] Embodiment 13. The device as set out in any preceding embodiment, wherein the or each flexible neck portion, when in a non-stressed position, has a substantially hourglass-like shape.

[0161] Embodiment 14. The device as set out in any preceding embodiment, wherein the or each flexible neck portion has a substantially circular cross-section when viewed along a longitudinal axis thereof at a waist thereof.

[0162] Embodiment 15. The device as set out in any preceding embodiment, wherein the or each flexible neck portion is hollow.

[0163] Embodiment 16. The device as set out in any preceding embodiment, wherein at least one of the sections has a substantially circular cross-section when viewed along a longitudinal axis thereof.

[0164] Embodiment 17. The device as set out in any preceding embodiment, wherein the sections of the casing and the flexible neck portions are each made of silicone and integrally moulded, and wherein the flexible neck portions have a lower hardness rating and / or a lower wall thickness than the sections of the casing.

[0165] Embodiment 18. The device as set out in any preceding embodiment, wherein at least one of the sections has a substantially rectangular cross-section when viewed along a longitudinal axis thereof.

[0166] Embodiment 19. The device as set out in embodiment 18, wherein the substantially rectangular cross-section has rounded corners. Embodiment 20. The device as set out in embodiment 18 or 19, wherein the section having the substantially rectangular cross-section is the section furthest away from the fluid inlet, and wherein said section is rounded at an end thereof furthest away from the fluid inlet.

[0167] Embodiment 21. The device as set out in any preceding embodiment, wherein the actuator is contained within the section of the casing located closest to the fluid inlet.

[0168] Embodiment 22. The device as set out in any preceding embodiment, wherein the actuator is separated from the valve by a seal.

[0169] Embodiment 23. The device as set out in any preceding embodiment, wherein the actuator is located within a hermetically sealed compartment.

[0170] Embodiment 24. The device as set out in any preceding embodiment, further comprising control circuitry operably coupled to the actuator, the control circuitry being contained within the section of the casing located closest to the section containing the actuator.

[0171] Embodiment 25. The device as set out in embodiment 24, wherein the control circuitry is communicable with a wireless communications device located outside of the body so as to enable control over the actuator using said wireless communications device.

[0172] Embodiment 26. The device as set out in embodiment 24 or 25, wherein the device further comprises an antenna, operably coupled to the control circuitry, the antenna being contained within the same section of the casing as the control circuitry.

[0173] Embodiment 27. The device as set out in any of embodiments 24 to 26, further comprising an energy storage device, coupled to the control circuitry, contained within the section of the casing located furthest away from the fluid inlet. Embodiment 28. The device as set out in any preceding embodiment, further comprising a resilient outlet tube extending between the fluid inlet and the fluid outlet.

[0174] Embodiment 29. The device as set out in embodiment 28, wherein the device is arranged such that, in use, the outlet tube is substantially located in a urethra, the outlet tube being arranged to inhibit movement of the device towards the bladder.

[0175] Embodiment 30. The device as set out in embodiment 28 or 29, wherein the resilient outlet tube is releasably attachable to the valve section.

[0176] Embodiment 31. The device as set out in embodiment 30, wherein the device comprises a clip mechanism to releasably attach the resilient outlet tube to the valve section.

[0177] Embodiment 32. The device as set out in any of embodiments 28 to 31 , wherein the outlet tube, when in a non-stressed position, comprises a substantially straight portion extending from the fluid inlet and a curved portion located between the substantially straight portion and the fluid outlet.

[0178] Embodiment 33. The device as set out in embodiment 32, wherein the curved portion of the outlet tube permits bending around at least one axis so as to straighten the outlet tube.

[0179] Embodiment 34. The device as set out in any of embodiments 28 to 31 , wherein the outlet tube further comprises a retainer arranged, in use, to remain outside the body.

[0180] Embodiment 35. The device as set out in embodiment 34, wherein the retainer comprises one or more structures that extend perpendicularly from the outlet tube.

[0181] Embodiment 36. The device as set out in embodiment 34 or 35, wherein the retainer comprises a plate structure. Embodiment 37. The device as set out in any of embodiments 28 to 36, wherein the fluid outlet is positioned at an end of the resilient outlet tube furthest from the fluid inlet, that end of the resilient outlet tube being laterally compressible so as to allow partial collapse of the fluid outlet.

[0182] Embodiment 38. The device as set out in embodiment 37, wherein the outlet tube comprises one or more holes in a side wall thereof located near to the fluid outlet.

[0183] Embodiment 39. The device as set out in embodiment 37 or 38, wherein the outlet tube comprises a tapering portion located towards the fluid outlet, the tapering portion tapering narrowing towards the fluid outlet.

[0184] Embodiment 40. The device as set out in any of embodiments 37 to 39, wherein the outlet tube comprises a portion of reinforcing material located near to the fluid outlet arranged to permit lateral compression and to resist expansion.

[0185] Embodiment 41. The device as set out in any of embodiments 28 to 40, wherein the outlet tube comprises a constricted portion arranged such that, in use, it is located substantially adjacent to a urethral sphincter.

[0186] Embodiment 42. The device as set out in embodiment 41 , wherein the constricted portion of the outlet tube comprises reinforcing material.

[0187] Embodiment 43. The device as set out in embodiment 42, wherein the reinforcing material comprises a mesh and / or one or more helical coils.

[0188] Embodiment 44. The device as set out in embodiment 43, wherein the reinforcing material is formed integrally with the constricted portion.

[0189] Embodiment 45. The device as set out in any of embodiments 28 to 44, further comprising a compressible material, such as a compressible tube or compressible jacket, provided around the outlet tube. Embodiment 46. The device as set out in embodiment 45 and embodiment 41 , wherein the compressible material is provided around the constricted portion.

[0190] Embodiment 47. The device as set out in embodiment 45 or 46, wherein the compressible material is foam.

[0191] Embodiment 48. The device as set out in any of embodiments 45 to 47, wherein the compressible material is arranged to compresses in the radial dimension by a factor of at least 2.

[0192] Embodiment 49. The device as set out in any preceding embodiment, wherein the first section of the casing is connected to a valve section comprising the fluid inlet and the valve, at least a portion of the valve section being positioned within the first section.

[0193] Embodiment 50. The device as set out in embodiment 49, wherein the first section of the casing is rigidly connected to the valve section.

[0194] Embodiment 51. The device as set out in any of embodiments 28 to 50, wherein the resilient outlet tube is releasably attached to a valve section comprising the fluid inlet and the valve, at least a portion of the valve section being positioned within the first section.

[0195] Embodiment 52. The device as set out in embodiment 51 , wherein at least a portion of the valve section is positioned within a portion of the outlet tube when the outlet tube is attached to the valve section.

[0196] Embodiment 53. The device as set out in embodiment 51 or 52, wherein the outlet tube comprises a constricted portion arranged such that, in use, it is located substantially adjacent to a urethral sphincter, and the valve portion comprises a constricted portion which is releasably attached to the outlet tube, the constricted portion of the valve portion being at least partly positioned within the constricted portion of the outlet tube when the outlet tube is attached to the valve section. Embodiment 54. The device as set out in any of embodiments 49 to 53, wherein the fluid inlet is formed in a side wall of the valve section.

[0197] Embodiment 55. The device as set out in any preceding embodiment, comprising a resilient skirt arranged, in use, to inhibit movement of the device towards the urethra, the resilient skirt being positioned between the fluid inlet and the fluid outlet.

[0198] Embodiment 56. The device as set out in embodiment 55, wherein the resilient skirt is positioned substantially adjacent to the fluid inlet.

[0199] Embodiment 57. The device as set out in embodiment 55 or 56, wherein the resilient skirt comprises one or more radially extending ridges.

[0200] Embodiment 58. The device as set out in embodiment 55 or 56 or 57, wherein the resilient skirt comprises a plurality of radially extending ridges having a portion of material extending therebetween, each of the radially extending ridges having a greater thickness than the material extending therebetween.

[0201] Embodiment 59. The device as set out in embodiment 58, wherein, when in a non-stressed position, the resilient skirt comprises a first face which is substantially smooth and a second face comprising the radially extending ridges protruding therefrom, the first face facing away from the fluid inlet and the second face facing towards the fluid inlet.

[0202] Embodiment 60. The device as set out in embodiment 57, 58 or 59, wherein the or each radially extending ridge has a notch at its radially inner end.

[0203] Embodiment 61. The device as set out in embodiment 60, wherein the or each radially extending ridge tapers in thickness towards the radially inner edge.

[0204] Embodiment 62. The device as set out in embodiment 61 , wherein the angle of the taper is in a range of 20 to 60 degrees to the axis of the device. Embodiment 63. The device as set out in any of embodiments 55 to 62, wherein the resilient skirt, when in a non-stressed position, is substantially planar.

[0205] Embodiment 64. The device as set out in any of embodiments 55 to 63, wherein the resilient skirt permits folding into a substantially tube-shaped configuration wrapping around one or more other components of the device.

[0206] Embodiment 65. The device as set out in any of embodiments 55 to 64, wherein the resilient skirt is arranged to fold into a substantially tube-shaped configuration wrapping around a portion of the device during insertion of the device into a urethra, and arranged to fold into a substantially tube-shaped configuration wrapping around a different portion of the device during extraction of the device from a urethra.

[0207] Embodiment 66. The device as set out in any of embodiments 55 to 65, wherein the resilient skirt is arranged, in use, to permit folding into a substantially truncated-cone-shaped configuration located at least partially in a urethral opening of a bladder, with the base of the truncated-cone shape facing towards the bladder.

[0208] Embodiment 67. The device as set out in any of embodiments 55 to 66, wherein the resilient skirt is integrally moulded with a or the resilient outlet tube extending between the fluid inlet and the fluid outlet.

[0209] Embodiment 68. The device as set out in any of embodiments 55 to 67, wherein the skirt reduces in thickness between its radially inner edge and its radially outer edge.

[0210] Embodiment 69. The device as set out in embodiment 68, wherein the reduction in thickness forms a smooth taper or a stepped taper.

[0211] Embodiment 70. The device as set out in embodiment 68 or 69 and as set out in any of embodiments 57 to 62, wherein each radially extending ridge reduces in thickness between its radially inner edge and its radially outer edge. Embodiment 71. The device as set out in any preceding embodiment, wherein at least a portion of the device comprises a magnetic material so as to enable a magnetic extraction device, insertable into a urethra, to releasably attach to the device for extraction of the device through the urethra.

[0212] Embodiment 72. The device as set out in embodiment 71, wherein the portion of the device comprising a magnetic material is located, while the device is in use, in the urethra. Embodiment 73. The device as set out in embodiment 71 or 72, wherein the portion of the device comprising a magnetic material is located at or near to the fluid outlet.

Claims

CLAIMS1. A device for controlling urinary flow, comprising: a fluid inlet; a fluid outlet; a valve movable between an open position in which fluid can flow from the fluid inlet to the fluid outlet and a closed position in which fluid flow is blocked between the fluid inlet and the fluid outlet; an actuator operable to move the valve between the open position and the closed position; and a casing positioned on a first side of the fluid inlet, the casing comprising a first section resiliently connected to a second section by a first flexible neck portion, the first and second sections each having a higher rigidity than the first flexible neck portion; wherein the fluid outlet is positioned on a second, opposite side of the fluid inlet.

2. The device as claimed in claim 1, wherein the device is insertable into a urethra and arranged such that, in use, the casing is located in a bladder.

3. The device as claimed in any preceding claim, wherein the casing further comprises a third section resiliently connected to the second section by a second flexible neck portion; and optionally wherein the casing forms an overall curved shape when the or each flexible neck portion is in a non-stressed position.

4. The device as claimed in any preceding claim, wherein the or each flexible neck portion permits bending around at least one axis, preferably around at least two axes, preferably around any axis perpendicular to a longitudinal axis of a respective sections connected thereto.

5. The device as claimed in any preceding claim, wherein the or each flexible neck portion permits a relative twisting motion between the respective sections connected thereto.

6. The device as claimed in any preceding claim, wherein the or each flexible neck portion is hollow.

7. The device as claimed in any preceding claim, wherein the sections of the casing and the flexible neck portions are each made of silicone and integrally moulded, and wherein the flexible neck portions have a lower hardness rating and / or a lower wall thickness than the sections of the casing.

8. The device as claimed in any preceding claim, wherein at least one of the sections has a substantially rectangular cross-section when viewed along a longitudinal axis thereof; and optionally wherein the substantially rectangular crosssection has rounded corners.

9. The device as claimed in claim 8, wherein the section having the substantially rectangular cross-section is the section furthest away from the fluid inlet, and wherein said section is rounded at an end thereof furthest away from the fluid inlet.

10. The device as claimed in any preceding claim, wherein the actuator is contained within the section of the casing located closest to the fluid inlet.11 . The device as claimed in any preceding claim, further comprising control circuitry operably coupled to the actuator, the control circuitry being contained within the section of the casing located closest to the section containing the actuator.

12. The device as claimed in claim 11 , further comprising an energy storage device, coupled to the control circuitry, contained within the section of the casing located furthest away from the fluid inlet.

13. The device as claimed in any preceding claim, further comprising a resilient outlet tube extending between the fluid inlet and the fluid outlet; and optionally wherein the device is arranged such that, in use, the outlet tube is substantially located in a urethra, the outlet tube being arranged to inhibit movement of the device towards the bladder.

14. The device as claimed in claim 13, wherein the outlet tube, when in a nonstressed position, comprises a substantially straight portion extending from the fluid inlet and a curved portion located between the substantially straight portion and the fluid outlet.

15. The device as claimed in claim 13 or 14, wherein the outlet tube comprises a constricted portion arranged such that, in use, it is located substantially adjacent to a urethral sphincter.

16. The device as claimed in claim 15, wherein the outlet tube is releasably attached to a valve section comprising the fluid inlet and the valve, the valve section comprising a constricted portion which is releasably attached to the outlet tube, the constricted portion of the valve section being at least partly positioned within the constricted portion of the outlet tube when the outlet tube is attached to the valve section.

17. The device as claimed in claim 15 or 16, wherein the constricted portion of the outlet tube comprises reinforcing material.

18. The device as claimed in any of claims 13 to 17, further comprising a compressible material, such as a compressible tube or compressible jacket, provided around the outlet tube.

19. The device as claimed in claim 18 and claim 15, wherein the compressible material is provided around the constricted portion.

20. The device as claimed in claim 18 or 19, wherein the compressible material is arranged to compress in the radial dimension by a factor of at least 2.

21. The device as claimed in any preceding claim, comprising a resilient skirt arranged, in use, to inhibit movement of the device towards the urethra, the resilient skirt being positioned between the fluid inlet and the fluid outlet.

22. The device as claimed in claim 21, wherein the resilient skirt is positioned substantially adjacent to the fluid inlet.

23. The device as claimed in claim 21 or 22, wherein the resilient skirt comprises a plurality of radially extending ridges having a portion of material extending therebetween, each of the radially extending ridges having a greater thickness than the material extending therebetween.

24. The device as claimed in claim 23, wherein, when in a non-stressed position, the resilient skirt is substantially planar; and optionally comprises a first face which is substantially smooth and a second face comprising the radially extending ridges protruding therefrom, the first face facing away from the fluid inlet and the second face facing towards the fluid inlet.

25. The device as claimed in any of claims 21 to 24, wherein the resilient skirt permits folding into a substantially tube-shaped configuration wrapping around one or more other components of the device.

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