Abstract:
An implantable apparatus and a method for controlling fluid flow within a host body, for example for use as an incontinence device. A constricting member is provided for reducing fluid flow within a body canal when in a closed position, and for allowing fluid flow within the body canal when in an open position. In addition, there is a control mechanism for controlling movement of the constricting member between said open and closed positions. A link member links the constricting member and the control mechanism such that the constricting member and the control mechanism are implantable in different parts of the host body. A coupling for selectively transmitting axial movement to the link member may be provided between the link member and the control mechanism so that the constricting member cannot apply a damaging amount of force to the body canal.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a divisional patent application based upon and claiming the benefit of patent application Ser. No. 10/776,034, filed Feb. 10, 2004, now pending, which is a divisional patent application of Ser. No. 09/965,762, filed Sep. 28, 2001, now U.S. Pat. No. 6,689,046, issued Feb. 10, 2004, and is a continuation-in-part of patent application Ser. No. 09/676,336, filed Sep. 29, 2000, now U.S. Pat. No. 6,527,701, issued Mar. 4, 2003, the contents of these applications and patents is incorporated herein by reference thereto. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates to an implantable medical device and a method for the control of fluid flow through a body host canal or vessel, such as a urethra. 
       BACKGROUND 
       [0003]    Incontinence is a condition wherein persons lose control over their voluntary urinary function. The condition can arise from various causes, which include a variety of related and unrelated diseases, aging, and deterioration of the voluntary urethra sphincter muscle. The cost and inconvenience to persons suffering from this condition are great. Several remedies exist that are known in the prior art. Among these, the most common are surgical corrections both minor and major, drugs, devices and diaper capture systems which serve to capture discharges. Another solution is to place a patch over the urinary orifice to prevent unwanted discharge. Possibly, the most effective solution to date is the use of an artificial sphincter. This device is surgically installed and is hydraulically or pneumatically driven, operating by inflation of ballasts to suppress fluid flow. However, control of this device is sometimes difficult and is often inconvenient. Throughout the full range of the available treatment alternatives, the levels of efficacy, useful life, and complications vary greatly, with none of the current treatment alternatives being particularly effective in especially severe cases. Accordingly, there is a need for an improved apparatus to control the loss of voluntary urinary function. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention overcomes and alleviates the above-mentioned drawbacks and disadvantages in the art through novel implantable body fluid flow control devices for the control of fluid flow through a host body canal or vessel, such as a urethra. 
         [0005]    Generally speaking, and in accordance with a first aspect of the invention, an implantable apparatus for controlling fluid flow within a host body comprises a constricting member for allowing fluid flow within a body canal when in an open position and for reducing fluid flow within a body canal when in a closed position, an actuating member for operating the constricting member between said open and closed positions, and control means for operating said actuating member. 
         [0006]    Preferably, the constricting member comprises a first engaging element and a second engaging element for coupling to the first engaging element to encircle a body canal. At least one of the first engaging element and the second engaging element preferably has apertures to allow tissue growth therethrough from and to the surface of the body canal. A locking member is preferably provided for locking the first engaging element and second engaging element into the locked position. 
         [0007]    The constricting member preferably comprises a plunging member moveable such that the plunging member may apply pressure against said body canal to compress said body canal into said closed position. The actuating member preferably comprises a connector having first- and second ends. The first end of the connector is preferably attached to said plunging member and is axially moveable by said control means to move said plunging member. 
         [0008]    The actuating member may comprise a housing whereby the second end of the connector extends slidably through an aperture in the housing and is coupled to an actuator provided in the housing, for example physically or by way of magnetic fields, such that movement of the actuator results in movement of said plunging member away from the body canal to allow at least some fluid flow therethrough. The actuating member preferably comprises a motor operatively coupled to the second end of the connector so that activation of the motor causes the second end of the connector to be axially pulled towards the motor resulting in movement of said plunging member away from the body canal to allow at least some fluid flow therethrough. 
         [0009]    A trigger mechanism is preferably provided for activating the motor. The trigger mechanism may be a magnetically operated switch, a radio-controlled circuit, a manually operated button implanted under the patient&#39;s skin, or any other suitable trigger mechanism. A manual override system may also be included. The manual override system may include a magnet that can be used outside the patient&#39;s body. 
         [0010]    A second aspect of the invention provides an implantable apparatus for controlling fluid flow within a host body comprising a constricting member for restricting fluid flow within a body canal when in a closed position, and for allowing fluid flow within the body canal when in an open position; a control mechanism for controlling movement of the constricting member between said open and closed positions; and a link member linking the constricting member and the control mechanism such that the constricting member and the control mechanism are implantable in different parts of the host body. 
         [0011]    The control mechanism can be separable from said link member so that said control mechanism may be replaced without removal of the constricting member or the link member from the host body. 
         [0012]    Preferably, the link member is adapted for moving said constricting member between said open and closed positions so as to alter fluid flow within the body canal, and an actuating member is preferably provided for actuating said link member. The link member may be a cable provided in a protective sleeve, or may be any other suitable link between the constricting member and the control member such as a wire carrying electronic control signals, a wireless radio communication system, etc. 
         [0013]    The actuating member and the control mechanism are preferably provided in a housing separate from the constricting member. The actuating member is preferably a motor, most preferably with a remotely operated trigger mechanism, for example, a magnetically operated trigger mechanism, for activating the motor or magnetic unit from a position outside the patient&#39;s body. 
         [0014]    The motor or magnetic unit preferably acts through a worm gear. Preferably, the worm gear defines an axis, and the link member is attached to a casing, the worm gear co-operating with a threaded aperture provided in said casing in order to move said casing in a direction parallel to the axis of the worm gear. 
         [0015]    According to another aspect of the present invention, there is provided a seal for an elongated link member, the link member extending between an implantable apparatus for implantation in a host body and a control mechanism. The link member extends through an opening in a housing. The seal includes a tubular membrane having two openings, one opening being sealed to the housing, the other opening being sealed to the link member such that fluid entering the housing around the link member is trapped by the membrane. The membrane flexes to allow movement of the shaft. 
         [0016]    The membrane is preferably sealed to said link member by gripping means extending around the membrane and the shaft. The gripping means may comprise a coil. The membrane preferably comprises a bellows that folds inwardly when the link member is moved axially away from an interior of the housing, and expands when the link member is moved axially into the housing. The bellows may include a reinforcing ring so that folding of the bellows may be controlled. 
         [0017]    According to yet another aspect of the invention, there is provided an operating mechanism for a constricting member for controlling fluid flow in a body canal. The constricting member is actuable between open and closed positions. The operating mechanism includes an axially moveable link member operatively connected to the constricting member for actuating the constricting member. Operating means are provided for axially moving the link member. A coupling for selectively transmitting the axial movement is connected between the link member and the operating means. 
         [0018]    The coupling acts so that in one direction there is positive engagement between the operating means and the link member, whereas in an other direction, some play is allowed between the operating means and the link member. The coupling may be used so that opening of the body canal may be achieved by direct actuation of the operating means acting on the link member, but on closing of the body canal, the coupling prevents pressure being directly applied to the body canal by the operating means, thus reducing the likelihood of damage to the body canal. 
         [0019]    The coupling may include magnets or a compressible member. A magnet may be attached to the link member, and at least one other magnet may be attached to the operating means. The magnets may be physically moveable towards and away from each other, or they may be electromagnets such that they may be operated when required. The compressible member may be provided in a moveable casing. The link member may be operatively connected to the compressible member, the motor acting to move the casing, and the compressible member acting to move the link member. Alternatively, the coupling may include chain links or a jointed extensible framework, or other means of preventing direct application of pressure to the body canal. 
         [0020]    In the case of a coupling comprising magnets, a manual override system may be included, which manual override system comprises a further magnet operable from outside the patient&#39;s body. The manual override magnet should be of sufficient strength to move the magnet attached to the link member against the magnetic force of the magnet attached to the operating means. 
         [0021]    Another aspect of the invention provides a method of controlling fluid flow within a host body. The method includes implanting a constricting member around a body canal, the constricting member reducing fluid flow in the body vessel when in a closed position. The method further includes implanting a control mechanism in the host body; and providing and implanting a link member between the constricting member and the control mechanism to allow the control mechanism to control the constricting member. The control mechanism may be removed from the host body and replaced without removal of the constricting member and the linking member. 
         [0022]    The constricting member may include engaging elements defining an opening therebetween, the method including surrounding the body canal with the engaging elements so that the body canal extends through the opening. 
         [0023]    The method may further include suturing the engaging elements to the vessel. In addition, the control mechanism may be implanted remote from the body canal. 
         [0024]    Yet a further aspect of the invention includes a remote telemetry system for an implantable apparatus, the telemetry system including a signaling mechanism capable of sending and receiving signals to and from a control unit implanted in a host body in order to monitor the operation of the implantable apparatus, the telemetry system being capable of altering operating settings of the implantable apparatus. 
         [0025]    The signals are preferably electromagnetic radiation, most preferably radio signals. The implantable apparatus may include sensors to monitor actions of the implantable apparatus on the host body, and the telemetry system would include a mechanism to interrogate the sensors to provide feedback on the sensed data. Preferably, the sensors are capable of monitoring pressure exerted by a moveable part of the implantable apparatus on a part of the host body, the feedback on the sensed data including commands to alter the range of movement of the moveable part of the implantable apparatus. 
         [0026]    Another aspect of the invention includes an implantable apparatus for controlling fluid flow in a host body. The implantable apparatus includes a constricting mechanism including a reciprocable member for selectively applying pressure to a canal of the host body in order to selectively constrict the canal. A pressure sensor is included for detecting the pressure applied by the reciprocable member to the canal. A feedback system is also included for altering movement of said reciprocable member in response to the pressure sensed by said pressure sensor in order to prevent damage to said canal. 
         [0027]    The object and advantages of the implantable fluid flow control devices of the present invention permit implantation and use without severing the canal or vessel to be constricted. Moreover, because trauma is minimized with respect to the canal or vessel, and the devices of the present invention are relatively small, lightweight and made of corrosion-resistant material, such as durable plastics, titanium or stainless steel, the devices are suitable for use for extended periods of time to control fluid flow through numerous types of vessels to control, for example, urination, defecation, ejaculation, nutrition absorption for control of obesity, etc. Splitting the fluid flow control device and its control box also provides significant advantages. The surgery to implant the fluid flow control device is delicate and involved, whereas the surgery to implant the control box is much less involved as the control box may be implanted in an easily accessible place, just under the skin of the patient. Thus, when any part of the control box fails, the control box may be removed and replaced with a new control box without needing to adjust the fluid flow control device. The replacement of the control box does not therefore need to be done by a specialist surgeon, and may be performed in a large number of hospitals or even physicians offices under local anaesthetic. The surgery is thus much less traumatic for the patient and may be performed in a location that is convenient for the patient rather than in a hospital that is able to perform specialized urological surgeries. 
         [0028]    These and other objects, features and advantages of the present invention may be better understood and appreciated from the following detailed description of the embodiments thereof, selected for purposes of illustration and shown in the accompany drawings. It should therefore be understood that the particular embodiments illustrating the present invention are exemplary only and not to be regarded as limitations of the present invention. In particular, the illustrated embodiment relates to an artificial sphincter for a urethra, but it should be understood that the device can be used with any body fluid flow canal or vessel. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    The foregoing and other objects, advantages and features of the present invention, and the manner in which the same are accomplished, will become more readily apparent upon consideration of the following detailed description of the present invention taken in conjunction with the accompany drawings which illustrate a preferred and exemplary embodiment, and wherein: 
           [0030]      FIG. 1  is a front exploded view of a body fluid flow control device according to the invention; 
           [0031]      FIG. 2  is a side exploded view of the body fluid flow control device of  FIG. 1 ; 
           [0032]      FIG. 3  is a partial side view of the device of  FIG. 1  in the closed position; 
           [0033]      FIG. 4  is a partial front view of the device of  FIG. 1  in the closed position; 
           [0034]      FIG. 5  is a side exploded view of a control box and device for use with a body fluid flow control device; 
           [0035]      FIG. 6  is a partial top view of the control box and device of  FIG. 5 ; 
           [0036]      FIG. 7  is a partial cross-sectional view of a motorized activating member for use with the device of  FIG. 1  in the open position; 
           [0037]      FIG. 8  is a partial cross-sectional view of the motorized activating member of  FIG. 7  in an intermediate position; 
           [0038]      FIG. 9  is a partial cross-sectional view of the motorized activating member of  FIG. 7  in the closed position; 
           [0039]      FIG. 10  is a top partial cross-sectional view of an alternative embodiment of control box and device; 
           [0040]      FIG. 11  is an enlarged cross-sectional view of the joint between the cable and link member of  FIG. 10 ; 
           [0041]      FIG. 12  is a partial cross-sectional view of an alternative embodiment of motorized actuating member; 
           [0042]      FIG. 13  is a top partial cross-sectional view of yet a further alternative embodiment of control box and device; 
           [0043]      FIG. 14  is a partial cross-sectional view of the control device of  FIG. 13 ; 
           [0044]      FIG. 15  is a partial cross-sectional view of an alternative means of connecting a link member to a body fluid flow control device; and 
           [0045]      FIG. 16  is a partial cross-sectional view of a further alternative means of connecting a link member to a body fluid flow control device. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0046]    By way of illustrating and providing a more complete appreciation of the present invention and many of the attendant advantages thereof, the following detailed description is given concerning the novel implantable body fluid control device and uses thereof. 
         [0047]    Referring now in more detail to the drawings, in which like numerals refer to like parts throughout several views,  FIGS. 1-4  show a body fluid flow control device according to the present invention. The body fluid flow control device comprises a first engaging element  102  and a second engaging element  104 . When the first engaging element  102  is coupled with the second engaging element  104 , an inner diameter is formed which is suited for fitting around a host body canal, i.e., any tube or vessel V within the human or animal body, such as the urethra. 
         [0048]    The body fluid flow control device also comprises a locking mechanism  106  for locking the first and second engaging elements  102  and  104  together. The locking mechanism  106  may be of any suitable form. In the illustrated embodiment, locking mechanism  106  is in the form of locking pins  108  located on the first engaging element  102  and locking holes  110  located on the second engaging element  104 . In the illustrated embodiment, two locking holes  110  are provided on each side of engaging element  104 . Each locking pin  108  is capable of being attached to either of the locking holes  110 . The inner diameter formed between parts  102  and  104  may thus be adjusted for use with different sized vessels. It should be understood that any other equivalent locking mechanism can be used for this purpose. Alternative locking mechanisms contemplated by the present invention include, but are not limited to, the use of a strap and snap pins or interconnecting molding on the first and second engaging elements  102  and  104 . 
         [0049]    The body fluid flow control device of the present invention preferably further includes a piston-like or plunging member  112  located within the inner diameter formed by the coupling of the first and second engaging elements  102  and  104  such that the plunging member  112  may apply pressure against a body canal or vessel, such as a urethra. As can be seen most clearly from  FIGS. 2 and 15 , plunging member  112  may have a curved profile such that only outer edges of the plunging member contact the vessel surface in use. This substantially reduces the likelihood of necrosis of the tissue of the vessel because it allows pressure to be placed on the vessel over a smaller area than would be possible with a flat plunging member. The curved profile of plunging member  112  may be provided on a removable plunger head, so that a surgeon may select an appropriately sized plunger head for the size of the vessel. 
         [0050]    It should be appreciated that the fluid flow control device may take other forms than that illustrated. For example, instead of a plunging member provided in two engagement members, one of the engagement members could be moveable with respect to the other to compress the vessel in order to restrict fluid flow therein. Alternatively, a fluid flow control device in the form of an artificial external annular sphincter or other means for compressing the vessel may be applied to the vessel. 
         [0051]    Apertures  113  may be provided in first engaging element  102 . The apertures  113  permit tissue growth therethrough from and to the surface of the vessel in order to anchor the body fluid control device onto the vessel. Further apertures (not shown) may be provided to allow dissolvable sutures to be used to secure the engaging element to the vessel on a temporary basis, until the engaging element is completely anchored in place by the tissue growth. Alternatively, the material of the engaging element may be such as to allow suturing therethrough, or the engaging element may be otherwise attached to the vessel. It has been found that tissue growth is achieved within a few weeks of implantation of the device into a host body and so it may also be possible to implant the device without any form of attachment to the vessel, and to simply let the tissue growth firmly attach the device to the vessel over time. 
         [0052]    All components of the device are made from biologically inert and compatible materials. For example, the fluid flow control device may be made of polypropylene, silicone, titanium, stainless steel and/or Teflon. 
         [0053]    An actuating member is utilized by the body fluid flow control device of the present invention to bias the plunging member  112  to apply pressure against the body vessel when the body fluid flow control device is in the closed position, and to pull the plunging member  112  away from the vessel to open the device. The actuating member may comprise a cable  114  covered by a protective sleeve or sheath  116 , the cable  114  having a first end  118  and a second end  120 . Cable  114  is preferably a braided stainless steel cable, although any suitable material may be used. Protective sleeve  116  is preferably made from a bio-compatible material having non-stick properties to discourage tissue growth thereon. A suitable material is Teflon. The cable  114  may be slidably moveable within sleeve  116 , or cable  114  and sleeve  116  may be slidably moveable together. 
         [0054]    The first end  118  of the cable  114  runs slidably through an aperture (not shown) in the second engaging element  104  and is attached to the plunging member  112 . A collar  122  is provided around the sleeve  116  where it passes through the aperture in the second engaging element  104 , in order that any tissue growth on and around second engaging element  104  does not interfere with the movement of sleeve  116  through the aperture, if the sleeve  116  is designed to move with cable  114 . If cable  114  is slidably moveable within sleeve  116 , collar  122  prevents tissue ingress into the end of sleeve  116 . 
         [0055]      FIGS. 5-9  illustrate a control box for the fluid flow control device that is connected to end  120  of cable  114 . The control box comprises a housing  202 , a motor  204  having a worm gear  206 , a spring  208  and bellows  210  to provide a seal around sleeve  116 . The housing  202  may be made of polypropylene or any other suitable biologically inert material. Batteries  212  are also provided, which should preferably be suitable for implantation in the body, such as batteries manufactured by Wilson Greatbatch Ltd, of Clarence, N.Y., USA. An operating mechanism (not shown) may be provided in the control box, or may be implanted separately in the host body in an easily accessible place. 
         [0056]    The arrangement of the control box and cable  114  allows the control box to be implanted in the body separately from the fluid flow control device. For example, the control box may be implanted close to the patient&#39;s skin in their abdomen, with the cable  114  and sleeve  116  extending from the control box  202  to the fluid flow control device that is implanted around the urethra or other body vessel. 
         [0057]    Cable  114  is attached at end  120  to a nut  216  which is located in the interior of a slidably moveable casing  214  in housing  202 . Spring  208  is also located within casing  214 , which has a threaded aperture  218  to allow worm gear  206  to pass into the interior of casing  214 . 
         [0058]    Spring  208  is interposed between the motor  204  and cable  114  in order to provide a coupling for selectively transmitting axial movement from the motor  204  to the cable  114  and hence to the body vessel V, the operation of which is described with reference to  FIGS. 7 to 9  below. In the illustrated embodiment, the motor  204  acts on casing  214  to move spring  208  and cable  114  by means of the nut  216 . However, any suitable compressible member may be used in the casing  214  to cushion the vessel from the action of the motor, for example, a resiliently deformable material may be used, or a compressible fluid such as a gas could be used if casing  214  was suitably sealed. Alternatively, a spring or other compressible member may be connected directly to or inserted in cable  114 . Such an arrangement would preferably use a compressible member that was stiff enough so that pushing and pulling motions were still imparted to the cable  114  on operation of the motor. 
         [0059]    The slidable casing  214  and worm gear  206  allow axial movement to be imparted to cable  114  by motor  204 , but it should be appreciated that any suitable axial actuation of cable  114  may be used. For example, the motor  204  may have an axially moveable actuator, or suitable gearing could be provided to act on a toothed rack or other axially moveable element. Alternatively, the cable could have a flexible end that may be wound around an axle in housing  202 . 
         [0060]    The sleeve  116  containing cable  114  should be sealed to housing  202  to prevent ingress of body fluids from damaging the motor and other components of the control box. Any suitable seal may be used, but it should be noted that where sleeve  116  is designed to be slidably moveable, it is not possible to seal tightly around sleeve  116 , as the sleeve needs to be axially moveable in order to impart movement to plunging member  112 . One method of sealing sleeve  116  to housing  202  is to use a bellows mechanism. A suitable bellows mechanism  210  is illustrated in  FIGS. 7-9 . Bellows  210  is designed so that as sleeve  116  moves axially, bellows  210  expands or collapses in on itself so that fluid that seeps into housing  202  around sleeve  116  is captured by bellows  210 , and can be forced back out of the housing  202  when the device is moved to a closed position. 
         [0061]    The sleeve  116  may be sealed to bellows  210  and housing  202  by means of a threaded bolt  220 , and a nut  222 . Bolt  220  is passed through an aperture in housing  202  with its head  224  in the interior of the housing. Sleeve  116  passes through and is a close fit with a central bore  226  in bolt  220 . Bellows mechanism  210  is generally tubular and is sealed to the underside of head  224  of bolt  220  by an the O-ring seal  228 . As the nut  222  is tightened on bolt  220 , compression of the O-ring seal  228  causes a tight seal to prevent ingress of fluid into housing  202  around the exterior of bolt  220 . Bellows  210  extends around the head  224  of bolt  220  and is sealed to sleeve  116  in the interior of housing  202  by a tightly wound spring  230 . The spring  230  may be placed onto the bellows  210  before the sleeve  116  is forced through the bellows  210  and spring  230  in order to obtain the tightest seal possible. Other methods of sealing bellows  210  to sleeve  116  include cable clamps, C-clips, adhesive, etc. A reinforcing ring  234  is provided on one surface of bellows  210 , to ensure that the bellows  210  collapses correctly as the sleeve  116  is moved axially. The reinforcing ring  234  may be a thickened area in the wall of the bellows  210 , or may be a separate ring that is attached to the bellows, by gluing or any other suitable means. Instead, or in addition to, the reinforcing ring  234 , the bellows may be pleated or folded in order to ensure correct folding when the fluid flow control device is moved to the closed position. 
         [0062]    It should be noted that bellows  210  can be of any suitable shape, provided that a seal is made at the housing and around the sleeve, and that bellows allows movement of the sleeve into and out of the housing. For example, bellows  210  may be a simple tubular shape, with ends of the tube being sealed to the housing and sleeve. Alternatively, bellows  210  may be of a frustoconical shape, or a more complicated shape such as a bell-shape or could be folded or pleated. The seal to the housing could be close to the aperture in the housing through which the seal extends, as illustrated, either inside the housing or outside the housing. Alternatively, the seal could be made to the wall of the housing, around or behind the bolt  220 . 
         [0063]    It is possible to seal the sleeve  116  and the housing  202  without using a bellows mechanism, but it has been found that energy losses are created as movement of the sleeve  116  creates friction against the seal. This can cut the battery life of the motor by up to ⅓. For example, a flexible annular ring may be sealed between the sleeve  116  and the housing  202 , the annular ring stretching as the sleeve is axially moved. Alternatively, a series of seals may be provided along sleeve  116 , each seal preventing some fluid ingress to housing  202 . 
         [0064]    Control circuitry (not shown in  FIGS. 7-9 ) is provided, which operates the motor on receipt of a signal from an operating mechanism. Any of the several well-known control devices can be used to control the operation of the body fluid flow control devices of the present invention by a user so long as the objectives of the present invention are not defeated. Suitable operating mechanisms include radio-control devices, or a magnetic devices that can be sensed by the control circuitry. With a magnetic device, the user may be provided with a separate magnet that they carry with them, and which they position adjacent the skin over the implanted switch when they wish to operate the device. The magnet may be of any suitable shape, and may be shaped for example like a pen or credit card so that its purpose is not immediately apparent to other people. The magnet should have a weak magnetic field so that it must be placed close to the switch in order to operate the device, in order to prevent accidental operation of the device if the magnet is carried in a pocket. Alternatively, a touch sensor, infrared, voice or sound activation may be used, or a manually operated switch may be implanted under the skin of the patient. 
         [0065]    A remotely operated operating mechanism is preferred because the device can be operated without irritation to the skin, as would happen with a manually operated trigger. In the preferred embodiment, a manual override switch may be provided in addition to the remotely operated triggering mechanism. The manual override switch is designed to be used temporarily if the control box fails and the user is not close to a physician&#39;s office or hospital to have the control box changed. The manual override switch may be provided in the control box, and may be sealed from the interior of the control box until the first activation of the switch, for example by a membrane seal. Such a use of the manual override switch may eventually allow fluid ingress into the control box, which may then need to be replaced. Alternatively, no manual override switch may be provided, which would mean that the user would have to use incontinence pads until the control box could be replaced. 
         [0066]    The control circuitry controls operation of the motor, and may detect the position of the plunging member, for example, via the position of the casing or via the drag exerted on the motor. Preferably, the control circuitry also monitors the level of charge in the battery. The control circuitry can be used to initiate opening or prevent closing of the fluid flow control device if a problem such as low battery or a defective motor is detected, so that the device can be caused to remain in the open position. For example, once the device has been opened, an abutment (not shown) may be caused to contact the casing  214  to prevent any further movement thereof. The motor may also be shut off. The device may still be operable by a manual override, as the spring  208  can be compressed and allowed to expand within casing  214  to allow movement of the cable  114  to open and close the device. 
         [0067]    The control box  202  may also contain components that allow a physician to interrogate the control circuitry by a remote telemetry system without accessing the box itself. Such components may be interrogated and/or controlled by radio waves or other interactive signals transmitted and received by the telemetry system, or any other suitable mechanism. This allows the physician to check the charge in the batteries, any internal sensors, to alter the tension in the cable  114 , and to make other suitable adjustments. A pressure sensor may be provided on the plunger  112  to monitor the pressure between the plunger  112  and the vessel V when the plunger is in the closed position. The pressure sensor may also be interrogated by the telemetry system, which can then be used to alter the settings for the control device. For example, the number of turns that the motor  204  causes worm gear  206  to make on each operation of the device may be altered in order to set the correct distance of travel of the cable  114 , and hence plunger  112  for any particular patient so as to alleviate any excess pressure exerted on the vessel V. In addition, the telemetry system may include control commands to cause the motor to open and close the body fluid flow control device, either as an override system to the normal operating means, or in addition to the normal operating means in order to test the device in situ. 
         [0068]    If the control box causes the device to fail or remain in the open position if a problem is detected, this will simply mean that the patient will return to the condition that they were in before implantation of the device, in other words, in a condition of incontinence. If the device failed in the closed position, the patient would need to be catheterized. However, a manual override system would allow the patient to operate the system manually for a considerable period of time or until medical aid was obtainable. 
         [0069]    Actuation of the device is described with reference to  FIGS. 7 to 9 . In the open position shown in  FIG. 7 , the motor  204  has operated the worm gear  206  to draw casing  214  towards the motor  204 . This pulls nut  216  along with the casing  214 , and thus acts on cable  114  to pull the plunging member  112  away from the vessel V. Bellows  210  is also at its fully extended position. In order to close the fluid control device, the motor  204  is activated to turn worm gear  206  in the opposite direction to that used to open the device. As worm gear  206  is operated, casing  214  is moved away from the motor  204 , spring  208  pushing on nut  216  to bias plunging member  112  against the vessel V, as shown in  FIG. 8 . As the motor  204  is operated further, the vessel V prevents plunger  112  moving, and prevents movement of cable  114  and hence nut  216 , due to the increased force needed to move cable  114  against the vessel V when the vessel V is already closed. Nut  216  presses against spring  208 , causing compression of the spring  208 , as shown in  FIG. 9 . It can thus be seen that any further movement of worm gear  206  by motor  204  does not result in compression and injury of the vessel V, but the further compression of spring  208 . In this way, axial movement of casing  214  may be selectively transmitted to cable  114 . This protects the vessel V against failure of the device by continuous running of the motor  204 , as the vessel cannot be further compressed due to the interplay between the vessel V and the spring  208 . 
         [0070]    An alternative embodiment of the control box is illustrated in  FIGS. 10 and 11 . The control box comprises a housing  902 , a motor  904  having a worm gear  906 , a spring  908  and bellows  910 . Batteries  912  are also provided, along with control circuitry (not shown). The spring  908  is located in a slidable spring casing  914 . An operating mechanism (not shown) may be provided in the control box, or may be implanted separately in the host body in an easily accessible place. The spring, worm gear and motor arrangement are as described for  FIGS. 5-9 , and will not be further described. 
         [0071]    Housing  902  is preferably formed in two pieces, a main body  916  and an end lid  918 . End lid  918  includes a lip  920  that fits inside an end  922  of main body  916 . A groove  924  is provided around lip  920 , in order to receive an 0-ring  926 : End lid  918  is also sonically welded to main body  916  in order to provide a good seal. A groove  928  is provided around the exterior of end  922  of main body  916 , in order to allow for ease of removal of lid  918  with a suitable tool when necessary. An interior housing  930  extends along the length of housing  902 , to one side thereof, in order to separate the motor  904 , worm gear  906 , slidable casing  914 , bellows  910  and other moveable parts from the batteries  912 . Interior housing  930  has a flange  932  at an end  934  remote from end  922  of main body  916 , with an 0-ring groove  936  provided in flange  932 . A set screw  938  is also provided in interior housing  930 , in order to lock motor  904 . Electrical contacts  940  extend to motor  904  from end lid  918 . An internally directed collar  942  having an internal thread extends around flange  932  within housing  902 , and interior housing  930  is secured into housing  902  by means of an externally threaded nut  944  which is screwed into place to hold flange  932  in position. Nut  944  may have pin holes  946  to allow for tightening thereof. An externally directed collar  948  having an internal thread is also provided in housing  902 , in order to allow the cable  114  to pass into interior housing  930 . 
         [0072]    Sleeve  116  has an end  950  which is attached to a hollow connector  952  having a first end  954  and a second end  956 . At end  954 , connector  952  has backwardly-directed teeth  958  around the circumference thereof which attach to the inside of sleeve  116  adjacent to end  950 , and act to prevent sleeve  116  from being pulled loose. The second end  956  of connector  952  has an external thread  960 , as well as a groove  962  suitable for receiving an 0-ring  964 . Thread  960  is screwed into the internal thread provided within collar  948  on housing  902 . Cable  114  extends into housing  902  through connector  952 , and is attached at its end  120  to a link member  966  which extends into casing  914  and terminates in nut  216 . The connection between cable  114  and link member  966  is shown enlarged in  FIG. 11 . The cable end  120  is fitted into a connector piece  968  that has a tapered end  970  and a groove  972  for receiving a sealing ring. Link member  966  has an opening  974  for receiving connector piece  968 , opening  974  having an internal shoulder  976 . A metal 0-ring  978  is received by shoulder  976  and is held in place by a ring retainer  980 . Connector piece  968  is pushed into opening  974  until the metal 0-ring  978  seats in groove  972  to form a seal between connector piece  968  and link member  966 . 
         [0073]    Bellows  910  are attached to housing  902  by means of nut  944  screwed into inwardly directed collar  942 . Bellows  910  has an end flange  982 , which extends adjacent to flange  932  of interior housing  930 , and has an integral 0-ring  984  to seal in 0-ring groove  936  of flange  932  so that bellows  910  is tightly sealed to housing  902  by interior housing  930 . Bellows  910  is also attached to cable link member  966  by means of a cable link  986 , and has a pleated conical shape above flange  982  so that it may fold easily when compressed. It should be noted that in the embodiment of  FIG. 10 , the bellows  910  is not attached to the sleeve  116 , as the sleeve  116  is not axially moveable. Instead, cable  114  is axially moveable within sleeve  116 . In this embodiment, bellows  910  may not be necessary, as a good seal may be provided between connector  952  and control box  902 . However, it is advantageous to provide an additional seal, for example using bellows  910 , to prevent fluid ingress into control box  902 . 
         [0074]    The operation of the control box of  FIG. 10  is the same as for the control box of  FIGS. 5 to 9 , and will not be further described. 
         [0075]    A further alternative embodiment of a seal for the sleeve and an actuator for the cable is illustrated in  FIG. 12 . In the illustrated embodiment, control box  1200  is completely sealed so that no fluid ingress into the box can take place. A hollow cylindrical bore  1202  that is sealed at one end  1204  is formed in control box  1200 . Bore  1202  has internal threads  1206  provided adjacent an outer surface of control box  1200 . 
         [0076]    An end of sleeve  116  is attached to a hollow connector  1208 , connector  1208  having an end  1210  and an end  1212 . End  1210  of connector  1208  is dimensioned to pass into the end of sleeve  116 , connector  1208  having outwardly and rearwardly directed teeth  1214  at end  1210  to engage the interior of sleeve  116 , thereby securing connector  1208  to sleeve  116 . End  1212  of connector  1208  is dimensioned to be slightly larger in diameter than sleeve  116 , and has external threads  1216 . Connector  1208  may be screwed into bore  1202  of control box  1200  by means of threads  1216  and  1206 . 
         [0077]    End  120  of cable  114  is located in bore  1202 , and is provided with a collar  1218 . An annular magnet  1220  is supported by collar  1218  around end  120  of cable  114 . Cable  114  is axially moveable within sleeve  116 , and therefore a bellows seal is not necessary around sleeve  116 . In addition, as sleeve  116  is not moveable, tissue growth around the sleeve cannot affect the operation of the device. 
         [0078]    A motor  1222  has a threaded worm gear  1224  engaged with a casing  1226  through a screw-threaded aperture  1228  located in the bottom of the casing. Casing  1226  extends around bore  1202 , and an annular magnet  1230  is supported around the interior of an upper edge of casing  1226 . Magnet  1230  is aligned with magnet  1220  located on end  120  of cable  114 . 
         [0079]    In order to actuate cable  114  to open and close the fluid flow control device, the motor  1222  operates the worm gear  1224 , which moves casing  1226  along the exterior of bore  1202 . Magnet  1230  acts through the plastic material comprising bore  1202 , and causes magnet  1220  to track its movement. This in turn causes cable  114  to be axially moved, operating the fluid flow control device. If the motor  1222  continues operating the worm gear  1224  towards the cable  114  when the body vessel has already been closed, the attraction of magnet  1220  for magnet  1230  is not enough to cause the cable  114  to be moved further, due to resistance from the vessel walls, thus preventing potential damage to the vessel. Thus, axial movement of casing  1226  is selectively transmitted to cable  114 . In addition, the casing  1226  will come to rest against bore  1202  or an interior surface of control box  1200 , preventing the magnets from getting too far out of alignment. 
         [0080]    It should be appreciated that a magnetic link between the motor and cable may be achieved in many ways other than that illustrated in  FIG. 12 . For example, the magnets need not be annular, but could be placed to one side of the cable. In addition, the magnets need not operate by mutual attractions, but could work by repelling each other to close the vessel, with a spring action or other means operating to open the, vessel once the motor-driven magnet was pulled back towards the motor. With a repelling action, magnets could be placed directly on the ends of the cable and an axially movable actuator driven by the motor. 
         [0081]    An alternative embodiment of a magnetic coupling for selectively transmitting axial movement to the cable is illustrated in  FIGS. 13 and 14 . These figures illustrate a control box  1300  that is completely sealed. A bore  1302  having a blind end  1304  is provided in the control box  1300  for receiving the end  120  of cable  114 . A connector  1306  is used to connect sleeve  116  to bore  1302 . The connector  1306  has a first end  1308  with rearwardly directed teeth  1310 , a central shoulder  1312  and a second end  1314  having external screw threads  1316 . End  1308  of connector  1306  is pushed into the end of sleeve  116 , the teeth  1310  acting on the inner surface of the sleeve. End  1314  of connector  1306  is connected to control box  1300  by means of an 0-ring seal  1318  and an internally threaded nut  1320  which is threaded onto threads  1316 . Nut  1320  is welded at  1322  to the control box  1300  to form a tight seal. 
         [0082]    The cable  114  extends into bore  1302 . A cylindrical magnet  1324  is attached to end  120  of cable  114  by a collar  1326  which is deformed onto the magnet  1324  and cable end  120  for a tight fit. The control box  1300  includes a motor  1328 , a worm gear  1330  and batteries  1332  as described for the  FIG. 10  embodiment. A casing  1334  having an annular magnet arrangement  1336  is threaded onto worm gear  1330 , and operates in the same manner as in the  FIG. 10  embodiment so will not be further described. Control circuitry including IC&#39;s  1338  and other standard components  1340  including resistors and capacitors are also shown. 
         [0083]      FIG. 15  illustrates an embodiment of a connector joining first end  118  of cable  114  to the body fluid control device. Connector  1500  has a first end  1502  having outwardly directed teeth  1504  which grip into the inner surface of sleeve  116 . A second end  1506  of connector  1500  has a collar with inwardly directed threads  1508  which are threaded onto outwardly directed threads  1510  on a collar  1512  attached to the body fluid flow control device. An 0-ring  1514  forms a tight seal to the collar  1512 . 
         [0084]      FIG. 15  also illustrates plunger  112  in detail. Plunger  112  includes a perforated metal bracket  1516  attached to a metal collar  1518 . The main body of plunger  112  is formed of silicon that is molded onto the perforated bracket  1516 , the silicon extending through the perforations in the bracket to form a tight fit between plunger  112 , bracket  1516  and collar  1518 . Metal collar  1518  may be simply crimped onto end  118  of cable  118 . 
         [0085]      FIG. 16  illustrates a further alternative method of connecting cable  114  and sleeve  116  to the body fluid flow control device. In the embodiment of  FIG. 16 , the fluid flow control device has a collar  1600  with internal threads  1602 . A connector  1604  is used to connect sleeve  116  to collar  1600 . Connector  1604  has external threads  1606 , a central collar  1608  and outwardly directed teeth  1610 . It should be noted that connector  1604  may be the same as connector  1306  illustrated in  FIG. 13 . This allows for economies in manufacture, as only one type of connector need be provided for both ends of the sleeve  116 . A metal collar  1612  is used to connect the plunger (not shown in  FIG. 16 ) to end  118  of cable  114 . An 0-ring  1614  may seal between collar  1612  and connector  1604 . 
         [0086]    It will be understood that various embodiments of the present invention have been disclosed by way of example and that other modifications and alterations may occur to those skilled in the art without departing from the scope and spirit of the appended claims. Thus, the invention described herein extends to all such modifications and variations as will be apparent to the reader skilled in the art, and also extends to combinations and subcombinations of the features of this description and the accompanying figures. Although preferred embodiments of the present invention have been illustrated in the accompanying figures. and described in the foregoing detailed description, it will be understood that the present invention is not limited the embodiments disclosed, but is capable of numerous rearrangements, modifications and substitutions without departing from the spirit of the present invention as set forth and defined by the following claims, such as for example those embodiments described in non-provisional U.S. patent application Ser. No. 09/048,823, filed Mar. 26, 1998, which is incorporated hereinto in its entirety by reference.