GB2174911A - Prosthetic sphincter devices - Google Patents

Description

1 GB 2 174 911 A 1

SPECIFICATION

Prosthetic sphincter devices This invention concerns prosthetic sphincter devices 70 and more particularly such devices of the kind com prising a closed pressure-fluid system operable by the recipient to control a body duct.

Prior devices of this kind can be seen to involve in common four basic component parts, namely, a re servoirforthe pressure fluid, an inflatable duct obturating means, a pump facility operable bythe recipientto inflate and/or deflate the obturating means, and a control mechanism forthe pump facil ity, interconnected bytubing. Typicallythe device is.

wholly implantable, the pump facility is located sub cutaneouslyfor operation by palpation, and the obturating means is a cuff locatable around the urethra or other appropriate siteto act against urinary incontinence when inflated and to allow micturition when deflated.

In an earlierform of these devices, the pumpfacility and control mechanism comprise separate pumps connected, byway of valves, between the reservoir and cuff respectivelyfor inflation and deflation. The valves are essentially of unidirectional flowtypeto directthe pumped fluid appropriately, and also serve a pressure relief function to ensurethatthe cuff is not inflated above a preset pressure level.

In a subsequently developed form of the devices in 95 question there is a single pump connected, by way of the control mechanism, between the reservoir and cuff to deflate the latter. In this case the reservoir serves to hold fluid at a'preset pressure and the con- trol mechanism allows a restricted flow to the cuff to 100 maintain the same normally inflated at such pressure.

It will be appreciated, from obvious considerations and the explicit indiction forthe last-mentioned form of device, that devices of the kind in question have a normal operational state entailing inflation of the obturating means. It is to be noted at the same time thatthe pressure of such inflation should not besigni ficantly higher than the minimum level necessary to attain the desired result otherwise necrosis can occur in the adjacenttissue subjected to the pressure. Now, 110 while it may appear that the above forms of prior device can be satisfactory in this respect because each has a control mechanism operableto effect a normal preset inflation pressure, this assumes that an initial setting is satisfactory in all circumstances and can be chosen appropriately. In fact, experience shows that the pressu rised tissue can, with time, har den post-operatively so that a requirement can arise for an increased inflation pressure. An obvious dis advantage of the prior devices in this connection is that such a requirement is only accommodated by change of a component part and this necessitates furthersurgery.

An object of the present invention is to avoid this disadvantage and, to this end, the invention provides 125 a device of the kind in question in which the control mechanism is effective normally to preset a max imum inflation pressure level, such mechanism being adapted to allow adjustment of such preset level in situ post-operatively.

Preferablythe control mechanism of the invention involves a valve for communicating the reservoirand obturating means, and a source of fluid at preset pressure connected with said valveto hold the same normally closed, said soure including a self-sealing septum allowing flow of fluid therethrough byway of an injection instrumentto adjust said preset pressure.

In a more particularly preferred form of the invention there are separate inflation and deflation pumps, there is a first reservoirto hold working fluid and a second reservoirto hold fluid at said preset pressure, and said valve has a through passageway defined at least in part by an element movable to open and close the same, the deflation pump, first reservoir and obturating means being connected with said valve at one end of said passageway, the inflation pump being connected with said valve atthe other end of said passageway, and the second reservoir being connected with said valve to effect passageway- closing movement of said element.

The valve forthis last puspose is suitably of a flap or equivalentform with the movable element being a flexiblewall.

Lastly in this more general discussion of the inven- tion, it is to be noted thatthe proposed self-sealing septum affords advantages additional to that of allowing upward adjustment of the preset pressure and,forthis reason, anothersuch septum is preferablyconnected withthefirst reservoir.

In orderto facilitate afuller understanding ofthe invention the same will now be described bywayof examplewith referencetothe accompanying drawings, in which:

Figure 1 schematically illustrates the initially developed form of the invention, Figures2 to 5 illustrate detail of both an initially and subsequently developed construction forthe pump facility and control mechanism valve of Figure 1, and Figure 6 illustrates detail of a modification arising from the most recent development of the invention.

The device of Figure 1 comprises a valve 1 of the flap form mentioned above. This valve is constituted by a body 2 defining a chamber3 having three ports. Two of these ports denoted at 4 and 5 open into a wall portion of the chamber covered by a flexible flap 6 sealed around its edges with the chamber. The remaining port 7 opens into the chamber at another wall portion not covered bytheflap.

An inflatable obturating means in the form of a cuff 8, a bulb-form deflation pump 9, a first reservoir 10, and a first liquid access chamber 11 partly defined by a self-sealing septum 12 are connected in mutually communicating mannerwith the port4 of valve 1.

An inflation pump 13 of similar bulb form to pump 9 is connected with the port 5 of valve 1.

Lastly in the device, a second reservoir 14 and a second liquid access chamber 15 with self-sealing septum 16r respectively similarto reservoir 10 and chamber 11, are connected in mutually communicating mannerwith the port 7 of valve 1.

Use of the device involves complete implantation, with the cuff located around the urethra or other appropriate urinary duct site to be controlled, the pumps and fluid access chambers located sub- cutaneously respectively to facilitate palpation and 2 GB 2 174 911 A 2 injection instrument access, and the reservoirs are located abdominally orelsewhere in a site subjectto forces associated with stress incontinence. Obviously also, the system is filled with a pressurefluid, conveniently byway of the septa 12 and 16, the fluid in the second reservoir 14 being pressurised to a preset level which is initiallyjudged to be a minimum appropriate to effect urinary continence with the cuff inflated.

In operation, cuff inflation is effected by operation of the pump 13 to propel fluid at high pressure through the valve 1 into the cuff and the other components communicated therewith. This pressure will be above the preset pressure level within the second reservoir and acting also within the main body of the valve chamber, so that the valve flap lifts from the ports 5 and 4. Any excess of cuff pressure relative to the preset level will similarly, after inflation, maintain the valve open to allow a return flow of fluid to the pump until the cuff pressure decreases to the preset level, whereafterthe valve closes.

In the eventthat muscularforces occurwhich eievatethe bladder pressure abovethe preset level inthe cuff,these sameforceswiii atthesametime normally act on thefirst reservoirto correspondingly elevate the cuff pressure, and also on the second reservoirto hold the valve closed. Stress incontinence is accordingly accommodated without permanent application of an excess cuff pressure.

Cuff deflation to allow micturition is, of course, effected by operation of pump 9. Such operation will, like thatfor inflation, generate a pressure in excess of the preset level and so open the valve forf luidflow.

This flow conveys fluid to the pump 13 where it is, upon ceased deflation pumping, held by valve clo sure. Also, upon valve closure, the correspondingly reduced fluid volume in the cuff and associated corn ponents redistributes by re-entering the pump 9 and so the cuff pressure is reduced to a non-occluding level. This overall action is enhanced by locating the 105 pump 9 closerto the valvethan the cuff in terms of tubing connection lengths so thatthe greater drag in the path to the cuffs causes a preferential return fluid flowto pump 13.

As noted above, any incidence of post-operative incontinence due to inadequacy of the preset cuff inflation pressure in the short or longerterm can be accommodated by injection of fluid through the sep turn 12 to adjustthis last pressure upwardly.

The septa 12 and 16 can serve an additional func tion in the event thatthe device suffers a post operative fluid leakage. it is usual in the priordevices for use to be made of a fluid which is radio-opaque in orderto facilitate detection of the site of such leakage.

However, leaked fluid can in practice dissipate before examination is conducted to localise the leak. In the present case such examination is facilitated bythe abilityto re-fill the device. The septa can, of course, also be used forfluid removal if appropriate.

Construction of the device of Figure 1 suitably in volves a medical grade silicone rubber almost in its entirety, with mesh reinforcement in some areas such as the pump bulbs, such material being long proven in terms of biocompatibility and other appropriate properties.

In matters of detailed construction, the cuff maybe of any suitable geometry but normally will be of closed loop form or its equivalent, like a jubilee clip for example for purposes of adjustability. The two reservoirs are preferably each of hemispherical form mounted in mutual back-to-back assembly, as indicated by Figure 1, with their common wall being rigid. The control valve, pumps and liquid access chambers are preferably formed by a common assembly such as shown by Figures 2to 5.

In an initial embodiment this assembly was of sandwich form made up from three sub-components respectively illustrated by Figures 2 to 4 in plan view forthe base, middle and top, and with the overall assembly shown by Figure 5 inside elevation.

The base of Figure 2 is essentially a slab which is recessed on its upper side to provide the valve chamber 3, part of each of thefluid access chambers 1 land 15, and respective passageways for communication with the reservoirs 10 and 14.

The middle of Figure 3 is also essentially a slab of like perimeterto that of the base for registration thereover. This middle slab is apertured to provide the ports 4 and 5, a flexible sheet defining the flap 6 being sealed around its edges belowthe slab to cover the ports. Apertu ring is also effected to continue the chambers 1 land 15, and to communicate chamber 11 with the passageway to reservoir 14. In addition the upper surface is recessed to communicate the chamber 11 with the port4.

The top of Figure 4 has alike plan perimeterto that of the middle for registration thereover, but has upward convex formations as seen from Figure 5. Two of these formations are hemispherical to define the bulbs forthe pumps 9 and 14 and, in assembly,they respectively overlie the port 4 and reservoir 14 aperture on the one hand, and the port 5 on the other hand. The remaining formations definethe septa 12 and 16 with respective side walls therearound.

All of the elements of this assembly are suitably of silicone rubber exceptthatthe base is preferably stiffened with a sheet of ceramic or other material of appropriate properties.

It isthought useful to provide a template (not shown) to aid localisation of the septa of this assemblyforthe purposes of fluid transferto orfrom the assembly following implantation. This template will generally match, at least in plan outline, the upper surface of the assembly and have a respective injec- tion instrument guide bore in a position corresponding to the centre of each septum. In use, the assembly is manually located and the template positioned on the skin thereover in the best possible register. Even allowing thatthis register may not be perfect, the template bores nevertheless can then serveto guide an injection instrument appropriatelyto each septum.

Further development has given rise to an improved embodiment derived from that detailed in Figures 2 to 5. In this development the sandwich construction is simplified to require only two su b-components. The chambers 1 land 15 have rigid side walls to avoid any risk of puncture during injection of the septa. The assembly has an elevated side wall around the defla- tion pump 9, as indicated in chain line at 17 in Figures 3 GB 2 174 911 A 3 4 and 5, to obviate the risk of undesired deflation operation. The base portion of the assembly is formed with a flared projection in the end region where tube connections are made to the reservoirs 10 and 14, as indicated in chain line at 18 in Figures 4 and 5, to act against failure of such connections.

The most recent development of the invention con templates yetfurther improvement.

Firstly, benefit is thoughtto stem from use of a modified valve comprising opposed flexible walls in- 75 terconnected in the manner of a flattube of which the interior defines the valve passageway and the ex terior is subjectto the relevant preset pressure within a surrounding chamber. This is schematically illus trated in Figure 6 which deploys the the reference numerals of Figure 1 for corresponding elements but with the addition of "a"to distinguish the former.

Operation of the valve of Figure 1 could be subjectto variation by distortion of the wall 6 together with the adjacent chamberwall and the provision of the rigid base in the assembly of Figures 2 to 5 is intended to obviate such variation. Operation of the valve of Fi gure 6 is not subjectto such variation in normal cir cumstances and a rigid base is accordingly unneces sary. This is beneficial in terms of simplified construc- 90 tion and, more particularly, in reducing the need for the use of differing materials within the overall de vice. Also, operation of the valve of Figure 1 can vary due to creep of the flexible wall which mustflex resi liently. In the valve of Figure 6 operation can involve resilient movement atthe ends of the passageway whereby the walls 6a flex without significant creep inducing stress.

Secondly, benefit thoughtto be possible with use of separated reservoirs which are each wholly spher- 100 ical, this arrangement being compatible with an opti mum pressure/volume operating characteristic for the reservoirs. Also, separation of the reservoirs avoids the need for a rigid common wall and sofurth er reduces the need for use of different materials.

Claims (10)

1. A prosthetic sphincter device in the form of a closed pressu re-fl uid system operable by the reci- 110 pientto control a body duct, the device comprising, in operable interconnection in said system;- a reservoir for said pressurefluid; inflatable duct-obturating means; a pump operableto deflate said obturating means; and a control mechanism operable normallyto hold said obturating means inflated with saidfluid at a preset pressureto close said duct, said mechanism being adjustable in situ post-operativelyto vary said preset pressure.

2. A device according to Claim 1 wherein said control mechanism comprises a valve for communicating said reservoir and obturating means, and a source of fluid at said preset pressure connected with said valve to hold the same normally closed, said source including a self-sealing septum allowing flow of fluid therethrough byway of an injection instrumentto adjust said preset pressure.

3. A prosthetic sphincter device in theform of a closed pressure-fluid system operable by the recipientto control a body duct, which device comprises:- firstand second reservoirs respectivelyto hold working pressure fluid and pressure fluid at a preset pressure; inflatable duct-obturating means; first and second pumps respectively operableto inflate and deflate said obturating means; a valve having a through passageway defined at least in part by an element movable to open and close the same; and a chamber having a wall in the form of a self-sealing septum allowing flow of fluid therethrough byway of an injection instrument; said first reservoir, second pump and obturating means being connected with said valve at one end of said passageway; said first pump being connected with said valve at the other end of said passageway; said second reservoir being connected with said valve to effect passageway closing movement of said element under said preset pressure; and said chamber being connected with said second reservoirto allow adjustment of said preset pressure.

4. A device according to Claim 3 wherein said valve is of a flap form with said movable element being a flexible wall.

5. A device according to Claim 4 wherein said movable element comprises two flexible walls interconnected in the form of a lay flat tube of which the interior defines said passageway and the exterior is subjectto said preset pressure.

6. A device according to Claim 3,4or 5 comprising a furtherchamber having a wall in theform of a self-sealing septum, such further chamber being connected with said first reservoir.

7. Adevice according to anyone of Claims 3to 6 wherein said second pump is connected to said valve byway of a pressure fluid flow path of lesser resistance than thatfrom such pump to said obturating means.

8. Adevice according to anyone of Claims 3to7 wherein said pumps together with each said chamber are collectively located in an assembly on one side of a common base structure including said valve, and said reservoirs are each of substantially spherical shaping and remotely connected with said assembly.

9. A device according to Claim 8 wherein each said chamber includes a rigid side wall structure extending from its septum towards said base member.

10. A device according to any preceding claim wherein said obturating means is in the form of a cuff.

Printed in the UKfor HMSO, D8818935,9186,7102. Published by The Patent Office, 26Southampton Buildings, London, WC2A lAY, from which copies maybe obtained.