Abstract:
An implantable constriction device for treating an incontinent patient comprises an elongate composite structure adapted to constrict the urethra, urine bladder, anus, colon or rectum of the patient. The elongate composite structure is composed of a base material, such as hard silicone, making the composite structure self-supporting. Property improving means is provided for improving at least one physical property of the composite structure other than self-supporting properties, such as fatigue resistance, liquid impermeability, aggressive body cells resistance, anti-friction properties and lifetime.

Description:
[0001]     This application claims the benefit of Provisional Application No. 60/398,824, filed Jul. 29, 2002, the entire contents of which is hereby incorporated by reference in this application. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     The present invention relates to an implantable constriction device for constricting the urethra, urine bladder, anus, colon or rectum of an incontinent patient.  
         [0003]     This kind of constriction device, in the form of a banding device in which a band encircles and adjustably constricts a portion of a patient&#39;s urethra, urine bladder, anus, colon or rectum, has been used in surgery for treating anal and urinary incontinence. In practice, the band is made of silicone, which is a material approved and widely used for implantation. Moreover, the silicone band has an acceptable tensile strength and is fairly resistant to aggressive body fluids. Where the band is hydraulically adjusted, the hydraulic fluid used typically is an isotonic salt solution mixed with other conventional materials.  
         [0004]     A problem with traditional silicone bands, however, is that the silicone material gives the band certain inadequate properties, such as poor fatigue resistance and poor endurance of static bending forces, which over time might result in breakage of the band. Furthermore, silicone is a material that is semi-permeable by liquid, which is a drawback to hydraulic silicone bands, because hydraulic fluid can escape by diffusing through the silicone material. As a result, accurate adjustments of a hydraulic band are difficult to perform because of the loss of hydraulic fluid and the need for the patient to regularly visit a doctor to add hydraulic fluid to and calibrate the constriction device. These inadequate properties are serious, considering that the band is implanted for the rest of the patient&#39;s life. Another problem is that the band somewhat restrains the dynamic movements of adjacent organs necessary for the transportation of urine or fecal matter. As a consequence, the band might erode, and over time injure the urethra, urine bladder, anus, colon or rectum.  
       SUMMARY OF THE INVENTION  
       [0005]     The object of the present invention is to provide a new implantable constriction device for treating urinary and anal incontinence having improved properties as compared to traditional constriction devices.  
         [0006]     Accordingly, the present invention provides an implantable constriction device for treating an incontinent patient, the device comprising an elongate composite structure adapted to constrict the urethra, urine bladder, anus, colon or rectum of the patient, wherein the elongate composite structure is composed of a base material making the composite structure self-supporting and property improving means for improving at least one physical property of the composite structure other than self-supporting properties.  
         [0007]     In accordance with a first embodiment of the invention, the property improving means comprises a coating on the base material at least along a side of the elongate composite structure that is intended to contact the urethra, urine bladder, anus, colon or rectum, wherein the coating has better aggressive body fluid resistance than the base material. Such a coating may comprise a Teflon™ or Parylene™ coating, or a biocompatible metal coating such as gold, silver or titanium. As a result, the constriction device can be protected from damaging influences of aggressive body fluids, possibly for the rest of the patient&#39;s life.  
         [0008]     Where traditional silicone material constitutes the base material, a Teflon™ or Parylene™ coating also provides the composite structure with better anti-friction properties than the base material. Good anti-friction properties of the composite structure reduce the risk of the elongate composite structure eroding the urethra, urine bladder, anus, colon or rectum. This is proven by tests, in which the surface of traditional silicone bands has been polished before use. Accordingly, the test results indicate significant improvements in avoiding erosion of the urethra, urine bladder, anus, colon or rectum.  
         [0009]     Furthermore, the Teflon™, Parylene™ or metal coating also makes the composite structure, in which the base material is made of silicone, stronger than the traditional silicone band. A stronger band reduces the risk of fracture.  
         [0010]     In one alternative to the first embodiment, the elongate composite structure is designed for mechanical adjustment, such as the mechanical solutions disclosed in International Application No. WO 01/45486. In this alternative, the property improving means comprises a core of a soft viscoelastic material, such as silicone gel, typically having a hardness less than 20 Shure, cellulose gel or collagen gel. Where silicone gel is chosen, it may be “Med 3-6300” manufactured by Nusil. Hard silicone constitutes the base material, typically having a hardness of at least 60 Shure, and covers the soft core of viscoelastic material. The soft core makes the implanted elongate composite structure less injurious to the urethra, urine bladder, anus, colon or rectum, and reduces the injury of such organs. Furthermore, the soft core of viscoelastic material may be formed to enclose and protect mechanical adjustment components and other components of the composite structure, whereby fibrosis is prevented from growing into such components.  
         [0011]     In another alternative to the first embodiment, the elongate composite structure is designed for hydraulic adjustment, such as the hydraulic solutions disclosed in International Application No. WO 01/50833. In this alternative, the base material forms a closed tubing, which can be inflated by adding hydraulic fluid to the interior of the tubing and deflated by withdrawing hydraulic fluid from the interior of the tubing. The coating of Teflon™, Parylene™ or metal may cover the inner surface of the tubing. The base material may form two coaxial tubular layers of hard silicon, and the property improving means may comprise a tubular intermediate layer of a soft viscoelastic material located between the coaxial tubular layers. Alternatively, the base material may form an outer tubular layer and an inner arcuate layer attached to the outer tubular layer, the outer and inner layers defining a curved space extending longitudinally along the tubing. The property improving means may comprise a viscoelastic material filling the space. The tubing is applied around the urethra, urine bladder, anus, colon or rectum so that the space with viscoelastic material is located closest to the urethra, urine bladder, anus, colon or rectum. The viscoelastic material gives the advantages that erosion of the urethra, urine bladder, anus, colon or rectum is reduced and the risk of hydraulic fluid leaking from the tubing is decreased.  
         [0012]     In accordance with a second embodiment of the invention, the base material forms a first layer and the property improving means comprises a second layer applied on the first layer, wherein the second layer is more fatigue resistant than the first layer. The first layer preferably is comprised of hard silicone, whereas the second layer preferably is comprised of a polyurethane layer. In a traditional silicone band, especially the tubular type, that is formed in a loop to constrict the urethra, urine bladder, anus, colon or rectum, the inner surface of the band loop that contacts the urethra, urine bladder, anus, colon or rectum forms bulges and creases that repeatedly change as the band is subjected to dynamic movements from the urethra, urine bladder, anus, colon or rectum and when the size of the band is adjusted. As a consequence, the implanted traditional silicone band has the drawback that it may crack after some time due to fatigue of the silicone material. With the elongate composite structure of the invention, in which hard silicone may constitute the base material and a fatigue resistant polyurethane layer covers the silicone material on the side of the elongate composite structure that contacts the urethra, urine bladder, anus, colon or rectum, this drawback is eliminated.  
         [0013]     The property improving means suitably comprises a coating that may be coated on the layer of hard silicone and/or the layer of polyurethane, wherein the coating has better aggressive body fluid resistance properties and/or better anti-friction properties-.than hard silicone. As described above in connection with the first embodiment, the coating may comprise a Teflon™ or Parylene™ coating, or a biocompatible metal coating.  
         [0014]     The layer of hard silicone may form an inflatable tubing and the layer of polyurethane may cover the hard silicone layer within the tubing.  
         [0015]     In accordance with a third embodiment of the invention, the base material forms an inflatable tubing and the property improving means comprises a liquid impermeable coating coated on the base material. The coating may be coated on the external and/or internal surface of the tubing. Preferably, the liquid impermeable coating comprises a Parylene™ coating, or a biocompatible metal coating. Where hard silicone, which is a liquid semi-permeable material, constitutes the base material, the coating of Parylene™ or metal gives the advantage that the tubing may be inflated by hydraulic fluid under pressure without risking fluid diffusing through the silicone wall of the tubing.  
         [0016]     Also, in the third embodiment, the base material may form two coaxial tubular layers of hard silicon, and the property improving means may comprise a tubular intermediate layer of a soft viscoelastic material located between the coaxial tubular layers. Alternatively, the base material may form an outer tubular layer of hard silicone and an inner arcuate layer of silicone attached to the outer tubular layer. The outer and inner layers define a curved space extending longitudinally along the tubing and filled with the viscoelastic material. The tubing is intended to be applied around the urethra, urine bladder, anus, colon or rectum so that the space with viscoelastic material is located closest to the urethra, urine bladder, anus, colon or rectum.  
         [0017]     In accordance with a fourth embodiment of the invention, the property improving means comprises gas, such as air, contained in a multiplicity of cavities formed in the base material to improve the flexibility of the composite structure. In this case, Teflon™ advantageously constitutes the base material. The cavities may be defined by net structures of the Teflon™ material. Thus, the resulting composite structure of Teflon™ and cavities filled with gas is strong, flexible and aggressive body fluid resistant, and has good tensile strength and good anti-friction properties. Also, in the fourth embodiment, the elongate composite structure may comprise an inflatable tubing.  
         [0018]     The present invention also provides an implantable constriction device for treating an incontinent patient, comprising an elongate composite structure adapted to constrict the urethra, urine bladder, anus, colon or rectum of the patient, wherein the composite structure includes an elongate biocompatible self-supporting base material having surfaces exposed to aggressive body cells, when the constriction device is implanted in the patient, and a cell barrier coating on the surfaces to prevent body cells from breaking down the base material, which is typically silicone. If the base material were broken down by such body cells, typically macrophages or killer cells, histological particles would be spread in the human body.  
         [0019]     The barrier coating may comprise a Parylene™ coating or a biocompatible metal coating.  
         [0020]     Alternatively, the barrier coating may comprise a composite of different materials to achieve the cell-barrier protection as described above. There are several examples of such composite materials on the market, for example a composite of polyurethane and silicone called Elaston™.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS:  
       [0021]      FIG. 1  is a front view of a mechanical constriction device according to the present invention.  
         [0022]      FIG. 2  is an enlarged cross-section along the line II-II in  FIG. 1 .  
         [0023]      FIGS. 3 and 4  are modifications of the embodiment shown in  FIG. 2 .  
         [0024]      FIG. 5  is a front view of a hydraulic constriction device of the invention.  
         [0025]      FIG. 6  is an enlarged cross-section along the line VI-VI in  FIG. 5 .  
         [0026]      FIGS. 7-10  are modifications of the embodiment shown in  FIG. 6 .  
         [0027]      FIG. 11  is a modification of the embodiment shown in  FIG. 2 .  
         [0028]     Referring to the drawing figures, like reference numerals designate identical or corresponding elements throughout the several figures. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0029]      FIG. 1  illustrates a mechanical constriction device  2  according to the invention comprising an elongate composite structure  4  adapted to extend around and constrict the urethra, urine bladder, anus, colon or rectum of a patient. Referring to  FIG. 2 , the elongate composite structure  4  comprises a strong band  6  of nylon or the like, a tubular layer  8  of hard silicone, in which the band  6  slides, a soft layer  10  of a viscoelastic material, here a silicone gel having a hardness not more than 20 Shure, encircling the hard silicone layer  8 , and a tubular layer  12  of a self-supporting base material of hard silicone having a hardness of at least 60 Shure, surrounding the soft silicon layer  10 . A coating  14  of Teflon™, Parylene™ or a biocompatible metal, such as gold, silver or titanium, is coated on the outer hard silicone layer  12  to make the composite structure resistant to aggressive body fluids and to give the composite structure good anti-friction properties. A coating of Teflon™, Parylene™ or metal may also be coated on the internal surface of the inner tubular hard silicone layer  8  to reduce the friction between the nylon band  6  and the layer  8 . The constriction device  2  has an adjustment means  16  that can displace the end portions of the nylon band  6  relative to each other to either increase or decrease the constriction of the urethra, urine bladder, anus, colon or rectum.  
         [0030]      FIG. 3  shows an elongate composite structure  18  similar to that of  FIG. 2 , except that a layer  20  of a fatigue resistant material, here polyurethane, is applied on the hard silicone layer  12  along the inner side of the structure  18  that is intended to contact the urethra, urine bladder, anus, colon or rectum. Alternatively, the layer  20  may be tubular and surround the layer  12 .  
         [0031]      FIG. 4  shows a cross-section of an elongate composite structure  22  of an embodiment of the invention, in which Teflon™ constitutes the self-supporting base material, which is formed with a longitudinal cavity in which a strong nylon band  24  slides. Property improving means in the form of a gas, here air, contained in a multiplicity of cavities  26  are formed in the base material to improve the flexibility thereof.  
         [0032]      FIGS. 5 and 6  show a hydraulic constriction device  28  according to the invention comprising an elongate composite structure in the form of an inflatable tubing  30 , in which the base material of hard silicone forms an outer tubular layer  32  and an inner coaxial layer  34 . A viscoelastic material, here soft silicone gel, forms an intermediate layer  36  located between the tubular layers  32  and  34 . Four longitudinal partition walls  38  between the tubular layers  32  and  34  divide the intermediate layer  36  into four sections to prevent the silicone gel from displacing in the circumferential direction of the tubing  30 . (Also, the embodiments according to  FIGS. 2 and 3  may be provided with such longitudinal partition walls.) The outer layer  32  is coated with a coating  40  of Teflon™, Parylene™ or metal. Also, the inner layer  34  may be coated with a coating of Teflon™, Parylene™ or metal. If a Parylene™ or metal coating is chosen the composite structure will be completely liquid impermeable.  
         [0033]      FIG. 7  shows a tubing  42  similar to that of  FIG. 6 , except that an inner arcuate layer  44  is substituted for the inner tubular layer  34 . The arcuate layer  44  is attached to the outer tubular layer  32 , so that the outer tubular layer  32  and the arcuate layer  44  define a curved space extending longitudinally along the tubing  42 . A viscoelastic material, here silicone gel  46 , fills the space. In this embodiment there is no need for partition walls of the kind shown in the embodiment shown in  FIG. 6 . The tubing  42  is intended to be applied around the urethra, urine bladder, anus, colon or rectum so that the space with the protecting soft silicone gel  46  is located close to the urethra, urine bladder, anus, colon or rectum.  
         [0034]     As taught by the embodiment of  FIG. 7 , in the composite structures shown in  FIGS. 2 and 3 , the soft silicone gel may alternatively be applied in a longitudinal space close to the inner side of the elongate composite structure  4  and  18 , respectively, that is intended to contact the urethra, urine bladder, anus, colon or rectum.  
         [0035]     In the same manner as described above in connection with the embodiment of  FIG. 3 , a layer of a fatigue resistant material, here polyurethane, may be applied on the outer tubular layer  32  of hard silicone of the tubing  30  and  42 , respectively, along the side of the tubing  30  and  42 , respectively, that is intended to contact the urethra, urine bladder, anus, colon or rectum, when the tubing  30  and  42 , respectively, encircles the urethra, urine bladder, anus, colon or rectum.  
         [0036]      FIG. 8  shows a cross-section of an elongate composite structure  48  of an embodiment of the invention, in which Teflon™ constitutes the self-supporting base material, which is formed to an inflatable tubing  50 . Property improving means in the form of gas contained in a multiplicity of cavities  26  are formed in the base material to improve the flexibility of the tubing  50 .  
         [0037]      FIG. 9  shows a cross-section of a tubular composite structure of an embodiment of the invention, in which the self-supporting base material  52  is made of a polymer material suited for implantation, for example silicone or polyurethane. A property improving coating  54 , for example made of Parylene™, Teflon™ or metal, is applied on the external surface or on both the external and internal surfaces of the tubular structure  
         [0038]      FIG. 10  shows the same embodiment as  FIG. 9 , except that the base material comprises a layer  56  of polyurethane surrounded by a layer  58  of silicone.  
         [0039]      FIG. 11  shows a cross-section of a mechanical constriction device of another embodiment of the invention, comprising a double walled tubing  60 , an external wall  62  and an internal wall  64  spaced from the external wall  62 , of a self-supporting base material of hard silicone. The tubing  60  has partition walls  66  dividing the space between the external and internal walls  62  and  64 , respectively, of the tubing  60  into longitudinal cells  68 , which are filled with a soft viscoelastic material, for example silicone gel. The internal wall  64  is coated with a friction reducing coating  70 , for example made of Teflon™ or the like. A strong band  72  of nylon or the like slides in the tubing  60  on the friction reducing coating  70  to enable adjustment of the constriction device in the same manner as described above in connection with the embodiment according to  FIGS. 1 and 2 .  
         [0040]     Although the present invention has been described in terms of particular embodiments, it is not intended that the invention be limited to those embodiments. Modifications of the embodiments within the spirit of the invention will be apparent to those skilled in the art. The scope of the invention is defined by the claims that follow.