GB2489712A

GB2489712A - Implantable urine flow control valves

Info

Publication number: GB2489712A
Application number: GB1105741.1A
Authority: GB
Inventors: Mark Anthony Donbavand
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-04-05
Filing date: 2011-04-05
Publication date: 2012-10-10
Also published as: GB201105741D0

Abstract

An implantable urine flow control valve (10) comprises a valve member (14), an anchor (12) and a biasing element (16). The valve member has a valve head (24) for siting in a person's bladder (48), the valve head having an annular sealing region (46) for contacting the person's bladder, or a transition region between the person's bladder and urethra (50), around the urethra. The anchor is sited in and grips the person's urethra. The biasing element acts between the valve member and anchor for urging the valve head towards the anchor and thus for urging the sealing region of the valve head into sealing contact with the bladder or transition region. The valve member also includes a permanent magnet (30) or other magnetically responsive element so that the valve can be opened under the influence of a second external magnet.

Description

TITLE

Implantable urine flow control valves

DESCRIPTION

This invention relates to implantable urine flow control valves.

Many people suffer from urinary incontinence. One way of dealing with incontinence is to fit a urinary catheter leading to a urine collection bag carried by the person. However, this is very inconvenient for the person. Another way of dealing with the problem is to implant a valve which can be opened and closed by the person when they wish to urinate. Many designs of such valves have been proposed.

In a first class of such designs (see for example patent document U56623421B1), a valve is implanted in the urethra and can be actuated magnetically. A problem with implanting such devices in the urethra is that debris and crystallisation of urine in the device can lead to blockage and/or urinary tract infections. Also, there is a possibility that the urethra will callous around the device rendering subsequent removal difficult.

In a second class of such designs (see for example U56398718B1 and U56746421B1), a valve member is sited in the person's bladder and is normally held magnetically in a position in which it engages the bladder around the exit to the urethra to block the flow of urine; however, the valve member can be manipulated magnetically when desired so that it allows urine to flow from the bladder to the urethra. The risk of urinary tract infections is likely to be less with this class of design. However, it is expected that the valve member will not seal reliably. In the event that the valve member is accidentally dislodged from its closed position, it then needs to be manipulated magnetically back to its closed position.

An aim of the present invention, or at least of specific embodiments of it, is to provide a valve which seals reliably and is less likely to open unintentionally, which does not encourage urinary tract infections, and which facilitates subsequent removal of the valve.

In accordance with the present invention, there is provided an implantable urine flow control valve comprising a valve member having a valve head for siting in a person's bladder, the valve head having an annular sealing region for contacting the person's bladder, or a transition region between the person's bladder and urethra, around the urethra. The valve member also has a magnetically responsive element. The valve further comprises an anchor for siting in and gripping the person's urethra, and a biasing means acting between the valve member and anchor for urging the valve head towards the anchor and thus for urging the sealing region of the valve head into sealing contact with the bladder or transition region. Upon application of an appropriate externally generated magnetic field, the interaction of the magnetic field with the magnet causes the valve member to move against the action of the biasing means to release the contact between the sealing region and the bladder or transition region to permit urination. Upon removal of the magnetic field, the biasing means causes the valve member to return to its closed position.

Due to the presence of the biasing means acting between valve member and anchor, reliable closing of the valve can be achieved and unintentional opening of the valve can be avoided.

The valve member preferably has a valve stem projecting from the valve head for projecting into the urethra to assist in keeping the valve member in an appropriate orientation.

The magnetically responsive element is preferably disposed in the valve stem. At least part of the valve stem is preferably movable within the anchor so that the valve is not excessively long.

The biasing means preferably acts in tension between a distal end of the valve stem and the anchor.

The anchor preferably has an array of tines arranged for extending along and resiliently engaging the urethra. The tines preferably bow outwardly. The tines are preferably interconnected at the end of the anchor remote from the valve head. Partway along the anchor, the tines, when relaxed, preferably lie within a circle of a diameter which, in use, is greater than the relaxed internal diameter of the person's urethra in the vicinity of the anchor, so that the tines are resiliently deformed inwardly when the anchor is fitted to the urethra and the resulting frictional force between the tines and the urethra holds the anchor in position. In the event that the urethra callouses with the contacting portions of the tines, the longitudinal direction of the tines enables them to be slid out when it is desired to remove the valve. At the end of the anchor remote from the valve head, the tines preferably lie within a circle of a diameter which, in use, is less than the relaxed internal diameter of the person's urethra in the vicinity of the anchor so that the urethra does not touch or place any great pressure on the anchor at the interconnection of the tines at the remote end of the anchor and callousing will not occur there.

The biasing means preferably acts in tension between the valve member and the remote end of the anchor.

The valve head preferably comprises a hollow body, with the annular sealing region being provided on an outer surface of the hollow body facing generally towards the anchor.

The valve member preferably provides a bypass passageway extending in use from the bladder to the urethra, with a pressure release valve being provided in the bypass passageway.

The bypass passageway preferably includes a first aperture in use for the flow of urine from the bladder into the hollow body and a second aperture inside the annulus of the sealing region in use for the flow of urine from the hollow body to the urethra. The pressure release valve is preferably formed by an element inside the hollow body for closing the first aperture.

The valve member is preferably covered by a layer of biocompatible material. The anchor is also preferably covered in a layer of biocompatible material. In the case where both are covered, the biocompatible material of the layers preferably integrally forms the biasing means.

The magnetically responsive element is preferably a permanent magnet.

The valve may be provided in combination with a second magnet for actuating the valve.

The invention also extends to the use of a valve as described above.

A specific embodiment of the present invention will now be described, purely by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side view of a valve, as viewed in the direction of arrow 1 shown in Figure 4; Figure 2 is a sectioned side-view of the valve taken on the section line 2-2 shown in Figure 4; Figure 3 is a sectioned side view of the valve taken on the section line 3-3 shown in Figure 4; Figure 4 is an underplan view of the valve; Figure 5 is a sectioned underplan view of the valve taken on the section line 5-5 shown in Figure 1; Figure 6 is a schematic isometric view of a moulding of an anchor of the valve; and Figures 7A-C are side views of the valve fitted into a urethra with the valve closed (Figure 7A), the valve open under magnetic actuation (Figure 7B), and the valve open due to excess pressure (Figure 7C).

Referring to the drawings, a valve 10 is shown which is intended to be implanted in the human body to control the flow of urine from the bladder into the urethra. The valve 10 comprises an anchor 12, a valve member 14 and a resilient tension filament 16 which connects the valve member 14 to the anchor 12.

The anchor 12 comprises a ring 18 and six equiangularly spaced tines 20 which project from the ring almost parallel to the axis of the ring 18. However, the tines 20 bow outwardly slightly to describe a barrel shape. A bridge 22 extends diametrically across the ring 18. The ring 18, tines 20 and bridge 22 are integrally moulded from a skeleton 23 of plastics material such as polyurethane as shown in Figure 6.

The valve member 14 comprises a valve head 24 in the form of a hollow egg-shaped shell 26 and a stem 28 which projects axially from the big end of the shell 26. A strong rod-shaped permanent magnet 30, for example of Nd2Fe14B (neodymium), is contained in the stem 28 with its physical and magnetic axes coaxial with the stem 28. A hole 32 is formed in the side of the shell, and a valve pad 34 of larger diameter than the hole 32 is provided in the shell 26 behind the hole 32 and urged by a spring finger 36 towards the hole 32. Two arcuate slits 38 are formed in the shell 26 around the stem 28. A peak 40 is formed in the inner surface of the shell within the arcuate slits 38. The shell 26, stem 28, valve pad 34 and spring finger 36 may be integrally moulded from plastics material, such as polyurethane, for example by a combination of blow moulding and injection moulding. Alternatively, the shell 26, stem 28, valve pad 34 and spring finger 36 may be formed as two or more injection-moulded parts which are subsequently welded together.

The outer surfaces of the shell 26, the valve stem 28 and the skeleton 23 of the anchor 12 are coated in a layer 42 of silicone rubber which also extends between the distal end of the valve stem 28 and the centre of the bridge 22 to join the valve member 14 to the anchor 12 and to form the resilient tension filament 16. Slits 43 are formed in the layer 42 aligned with the slits 38 in the shell 26. The face of the valve pad 34 facing the hole 32 in the shell 26 is also coated in a layer 44 of silicone rubber. The silicone rubber of the layers 42,44 and filament 16 is impregnated with silver ions which, in use, leach to the outer surface of the layers 42 and filament 16 in order act as a bactericide. The silicone rubber is also impregnated with S glycosaminoglycan which, in use, leaches to the outer surface of the layers 42,44 and filament 16 in order to prevent or reduce bio film formation. In the region 46 of the layer 42 on the shell 26 surrounding the stem 28, the silicone rubber has a greater thickness and/or is made softer than the remainder of the layer 42. As will be explained below, this annular region 46 forms a seal with the bladder. Also, the layer 44 of silicone rubber on the valve pad 34 is relatively thick but is compressed by the force of the spring finger 36 where it makes contact with the inside surface of the shell 26 around the hole 32 so as to form a seal.

As shown in Figure 3, once coated with the layer 42 of silicone rubber, the proximal ends of the tines 20 adjacent the ring 18 lie within a circle of diameter Di. When the anchor 12 is relaxed, the distal ends of the tines 20 lies within a circle of larger diameter D2, and, part way along their lengths at the most bulbous position, the tines lie within a circle of even larger diameter D3. However, the skeleton 23 is resilient so that the tines 20 can be deflected inwardly. Also, as shown in Figure 2, with the tension filament 16 straight but relaxed, there is an axial spacing Si between the distal ends of the anchor tines 20 and the underside of the valve head 24.

Figure 7A shows the valve 10 fitted to the bladder 48 and the inlet end of the urethra 50 of a person. The valve 10 is chosen of such a size that the diameter Di at the proximal ends of the tines 20 is less than the relaxed inside diameter D4 of the urethra 50 and so that the maximum relaxed diameter D2 of the tines 20 is greater than the relaxed urethra diameter D4.

Therefore, when the anchor 12 is fitted to the urethra 50, the tines 20 are deformed inwardly so that their maximum diameter reduces from Dz to D5 and so that the maximum internal diameter of the urethra increases from D4 to Ds. The resultant frictional force between the tines 20 and the urethra 50 is sufficient to hold the anchor 12 in place. However, the ring 18 of the anchor 12 does not contact the urethra 50.

The anchor 12 is positioned so that the annular sealing region 46 of the valve head 24 seats on the bladder 48 or on the transition region 52 between the bladder 48 and the urethra 50 and so that the axial spacing between the distal ends of the anchor tines 20 and the underside of the valve head 24 is Sz, greater then the relaxed distance Si. The length of the tension filament 16 is therefore increased by S2 -Si, and the resultant tension in the filament 16 holds the annular sealing region 46 of the valve head 24 on the transition region 52 so that urine cannot escape therebetween. Also, absent any great pressure in the bladder 48, the valve pad 34 seals the hole 32 in the valve head 24.

Referring to Figure 7B, the valve 10 is supplied with a strong permanent magnet 54, for example of Nd2FeI4B (neodymium), which is used for voluntary actuation of the valve 10. When the actuating magnet 54 is appropriately positioned and oriented, external to the person's body, relative to the magnet 30 in the valve stem 28, the magnetic force between the magnets 30,54 causes the valve head 24 to move away from the anchor 12, increasing the axial spacing between the distal ends of the anchor tines 20 and the underside of the valve head 24 from Si to 53 despite the tension in the tension filament 16. The sealing region 46 of the valve head 24 therefore lifts away from the transition region 52 so that urine can escape from the bladder 48 into the urethra 50 as indicated by the arrows lines 56. When the person's bladder 48 is empty, the person removes the actuating magnet 54, as a result of which the tension filament 16 returns the valve to the position shown in Figure 7A.

Referring now to Figure 7C, in the event that the bladder 48 fills and the person does not, for whatever reason, voluntarily actuate the valve 10, the pressure of the urine in the bladder 48 acting on the valve pad 34 through the hole 32 in the valve head 24 will cause the valve pad 34 and its silicone layer 44 to move inwardly against the action of the spring finger 36. Urine can therefore escape from the bladder 48 through the hole 32 into the valve head 24 and thence through the slits 38 into the urethra 50, as indicated by the arrowed lines 58. For clarity, the opening of the valve pad 34 has been exaggerated in Figure 7C. In practice, the pad 34 will normally open only slightly, allowing urine to seep past it until the pressure of urine in the bladder 48 has decreased sufficiently for the spring finger 36 to cause the pad 34 to close again.

It will be appreciated that, with the valve 10 described above, the anchor 12 has a small area of contact with the urethra 50 in order to minimise the entrapment of urine which might result in urinary tract infection. Also, when properly fitted, the ring 18 at the end of the anchor 12 does not contact the urethra 50, and the urethra will therefore not callous around the ring 18.

In the event that the urethra 50 does callous along the tines 20, the callousing will extend longitudinally of the urethra 50 and therefore not present any significant hurdle to removal of the valve 10.

Many modifications and developments may be made to the embodiment of the invention described above. For example, instead of using a permanent magnet 30 in the valve stem 28, a piece magnetically responsive material such as soft iron may alternatively be employed.

It should be noted that the embodiment of the invention has been described above purely by way of example and that many other modifications and developments may be made thereto within the scope of the present invention.

Claims

CLAIMS(The reference numerals in the claims are not intended to limit the scope of the claims.) 1. An implantable urine flow control valve (10) comprising: a valve member (14) having: a valve head (24) for siting in a person's bladder (48), the valve head having an annular sealing region (46) for contacting the person's bladder, or a transition region between the person's bladder and urethra (50), around the urethra; and a magnetically responsive element (30); an anchor (12) for siting in and gripping the person's urethra; and biasing means (16) acting between the valve member and anchor for urging the valve head towards the anchor and thus for urging the sealing region of the valve head into sealing contact with the bladder or transition region.
2. A valve as claimed in claim 1, wherein: the valve member has a valve stem (28) projecting from the valve head for projecting into the urethra.
3. A valve as claimed in claim 2, wherein: the magnetically responsive element is disposed in the valve stem.
4. A valve as claimed in claim 2 or 3, wherein: at least part of the valve stem is movable within the anchor.
5. A valve as claimed in any of claims 2 to 4, wherein: the biasing means acts in tension between a distal end of the valve stem and the anchor.
6. A valve as claimed in any preceding claim, wherein: the anchor has an array of tines (20) arranged for extending along and resiliently engaging the urethra.
7. A valve as claimed in claim 6, wherein: the tines bow outwardly.
8. A valve as claimed in claim 6 or 7, wherein: the tines are interconnected at the end (18) of the anchor remote from the valve head.
9. A valve as claimed in any of claims 6 to 8, wherein: at the end of the anchor remote from the valve head, the tines lie within a circle of a first diameter (Di), and, partway along the anchor, the tines, when relaxed, lie within a circle of a second diameter (D2) greater than the first diameter.
10. A valve as claimed in any of claims 6 to 9, wherein: the biasing means acts in tension between the valve member and the remote end of the anchor.
11. A valve as claimed in any preceding claim, wherein: the valve head comprises a hollow body (26) and the annular sealing region is provided on an outer surface of the hollow body facing generally towards the anchor.
12. A valve as claimed in any preceding claim, wherein: the valve member provides a bypass passageway (32,38) extending in use from the bladder to the urethra; and a pressure release valve (34,36) is provided in the bypass passageway.
13. A valve as claimed in claim 12 when dependent on claim 11, wherein: the bypass passageway includes a first aperture (32) in use for the flow of urine from the bladder into the hollow body and a second aperture (38) inside the annulus of the sealing region in use for the flow of urine from the hollow body to the urethra.

-10 -
14. A valve as claimed in claim 13, wherein: the pressure release valve is formed by an element (34) inside the hollow body for closing the first aperture.
15. A valve as claimed in any preceding claim, wherein: the valve member is covered by a layer (42) of biocompatible material.
16. A valve as claimed in any preceding claim, wherein: the anchor is covered in a layer (42) of biocompatible material.
17. A valve as claimed in claim 16 when dependent on claim 15, wherein: the biocompatible material of the layers integrally forms the biasing means.
18. A valve as claimed in any preceding claim, wherein: the magnetically responsive element is a permanent magnet (30).
19. A valve as claimed in any preceding claim, in combination with: a second magnet (54).
20. The use of a valve as claimed in any preceding claim, wherein: the valve head is sited in a person's bladder with its annular sealing region contacting the person's bladder, or a transition region between the person's bladder and urethra, around the urethra; and the anchor is sited in and grips the person's urethra.
21. The use as claimed in claim 20, wherein: the relaxed internal diameter (D4) of the person's urethra in the vicinity of the anchor is greater than said first diameter and less than said second diameter.-11 -
22. An implantable urine flow control valve, or the use of such a valve, substantially as described with reference to the drawings.