Abstract:
The disclosure provides an incontinence prevention device provided with a loop type retention structure. The retention structure is in the form of a closed loop attached to the distal end of a shaft. The shaft is configured to function as an incontinence prevention device. The retention structure projecting laterally from and configured non-concentrically along the longitudinal axis of the shaft retains the incontinence prevention device within the patient. The retention structure may additionally include a protuberance extending therefrom. There is further provided a method for using the urethral catheter.

Description:
FIELD OF INVENTION 
     The present invention relates generally to incontinence prevention devices, and more particularly to an incontinence prevention devices having a non-concentric retention structures. 
     BACKGROUND OF INVENTION 
     Many adults suffer urinary incontinence although urinary incontinence is more common in women than in men. The increased frequency in women is due primarily to the laxity of the bladder support structures resulting from pregnancy and aging. Surgical correction is possible in some cases, but surgery is invasive, costly and dangerous. Urethral incontinence prevention devices, such as for example catheters, plugs and other similar devices, in most cases offer a better solution but can be cumbersome to use, can be expelled during bowel movements, and are typically relatively expensive to manufacture. 
     There are a wide variety of incontinence prevention devices available, including: catheters that have lumen for urine to flow through; valved catheters; plugs that prevent the flow of urine until the plug is removed; and cylindrical supports against which the spinchter seals the urethra to prevent the flow of urine. Foley catheters are one type of commonly used catheter. Foley catheters are essentially elongated tubes. They are placed in the urethra to drain urine through the central lumen. An inflatable balloon is included near the distal end of the tube serves as a retention structure. When inflated, the balloon holds the catheter in place. The proximal end of a Foley catheter typically has two ports: a drainage port to drain urine from the bladder and a balloon inflation port to inflate and deflate the balloon. The drainage port creates a permanent opening between the bladder and outside environment. Because the bladder is continuously emptied, the bladder&#39;s dome continuously rests on the tip of the catheter above the retention balloon causing compression, irritation and erosion of tissue as well as other tissue problems. Therefore, a need exists for a retention structure that does not protrude into the bladder such that it contacts the bladder&#39;s dome. 
     Plugs totally block the flow of urine. Therefore, the plugs typically require removal for the user to urinate. After removal, the old plug is not sterile and a new sterile plug must inserted into the urethra Plugs&#39; retention structures are typically cumbersome to operate and traumatic to the tissue. Thus, improper use can lead to irritation and infection from tissue traumatization. Further, the retention devices on the plugs are typically fluid filled and therefore relatively complex to manufacture. Therefore, a need exists for an incontinence prevention device that provides an atraumatic and simple means for insertion and removal and further reduces manufacturing costs. 
     Further, some urethral incontinence devices include open loop or pigtail type retention structures. These devices may be expelled when a user tenses the abdomen, such as when a user bears down during a bowel movement, because of a phenomenon called bladder neck drop often associated with incontinent female patients. With bladder neck drop, the bladder neck extends downward to encompass at least a portion of the urethra. The open loop type retention structures are thought to drop into the downward extension and thereafter could be entrapped in the urethra rendering it quasi-rectilinear as the bladder neck resumes its original shape. The improperly positioned device no longer functions properly and the quasi-rectilinear bladder retention structure can no longer maintain the device at its proper location permitting the user to later expel the device. Therefore, a need exists for an incontinence prevention device having a retention structure that maintains its appropriate position within the bladder neck regardless the physical forces acting on it, and can recover after momentary bladder neck drop. 
     In addition, typical incontinence prevention devices require, at least to some extent, that a proximal end extend from the urethral meatus. The proximal ends tend to scatter urine droplets during urination. The scattering of urine is inconvenient and unsanitary. Therefore, a need exists for a catheter that permits a directed stream of urine. 
     The present invention meet these needs and provides additional improvements and advantages that will be recognized by those skilled in the art upon review of the following description and figures. 
     SUMMARY OF THE INVENTION 
     The present invention further provides an incontinence prevention device that is simple and inexpensive to construct and easy to use. The incontinence prevention device of the present invention includes a shaft and a retention structure. The retention structure is configured as a closed loop non-concentrically disposed about a longitudinal axis of the shaft. The retention structure&#39;s closed loop tends to maintain the incontinence prevention device within the bladder neck. The retention structure&#39;s non-concentrically orientation accounts for the bladder&#39;s asymmetry. The retention structure may further include a protuberance projecting from the retention structure. The protuberance may project from a midpoint of the closed loop. The shaft may further include a lumen configured to receive a stylet. The lumen is typically coextensive with the shaft and substantially coextensive with the retention structure. In addition, the lumen may be coextensive with the protuberance. The device may also include a hydrogel coating disposed on its outer surface. The shaft may include an orientation marking at its proximal end. The proximal end of the shaft may also have a beveled edge to prevent the spraying of urine during urination. A segment of the retention structure may additionally define a cavity to receive another portion of the retention structure to further reduce the diameter for insertion. For insertion, the retention structure is rendered substantially rectilinear. A stylet may be provided to insert into a lumen in the device to render the retention structure substantially rectilinear. Once rectilinear, the device is inserted into the urethra so that the retention structure is placed within the bladder. Once in the bladder, the retention structure is reformed into a loop. The retention structure is then positioned adjacent the neck of the bladder with the non-concentrically disposed retention structure in a predetermined orientation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a perspective view of a urethral catheter showing a first embodiment of the retention mechanism; 
         FIG. 2  illustrates a left end view of the urethral catheter of  FIG. 1 ; 
         FIG. 3  illustrates a perspective view of a urethral catheter showing a second embodiment of the retention mechanism; 
         FIG. 5A  illustrates a side view of a stylet; 
         FIG. 5B  illustrates a side view urethral catheter of  FIG. 1  with a stylet partially inserted into the urethra measuring device; and 
         FIG. 5C  illustrates a side view urethral catheter of  FIG. 1  with a stylet fully inserted into the urethra measuring device. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention is applicable to a variety of devices that are maintained in the urethra. The invention is described in the context of an incontinence device for a woman&#39;s urethra for exemplary purposes. The appended claims are not intended to be limited to any specific example or embodiment described in this specification. It will be understood by those skilled in the art that the present invention may be used in related medical applications including but not limited to incontinence prevention devices, obstruction relief devices, drainage devices; or other similar devices which require retention in a lumen. Further, in the drawings described below, the reference numerals are generally repeated where identical elements appear in more than one figure. 
       FIG. 1  illustrates an embodiment of an incontinence prevention device  10  in accordance with the present invention. Device  10  includes a shaft  12 , a retention structure  14  and a proximal retention structure  15 . Device  10  may further includes a lumen  18 , shown in FIG.  2 . Device  10  is typically circular in cross-section although other shapes such as oval that allow the sphincter to sealably contract against the catheter&#39;s outer surface may also be used. Device  10  is typically composed of a flexible biocompatible material such as silicone, silastic, polyurethane, polyethylene, polyimide, PTFE, ETFE, or other materials or combinations of materials known to those skilled in the art. Typically, the material used has a durometer shore hardness of between about 30 and 95 shore A. In addition, device  10  may be coated with a lubricious material, such as a bydrogel, to allow for easier insertion and reduced irritation. 
     Shaft  12  is typically configured as a semi-rigid region of device  10  typically having a shape suitable for placement in the urethra Shaft  12  is further configured to have sufficient rigidity for sphincter muscles to contract against it so as to substantially stop the flow of urine from a user&#39;s bladder. Shaft  12  may also include an orientation marking  38 , shown in  FIGS. 5B and 5C  and discussed below. The orientation making may either be visible, for example a line or dot, or tactile, for example a crevice or dimple. Shaft  12  typically has a diameter of around 8 French to correspond with an appropriate size for insertion in an adult female&#39;s urethra. The device can be made with various other diameters ranging from between about 5 to 16 French to enable the proper sizing to accommodate the range of urethral sizes. The shaft typically has a length of between about 3.5 to 4.5 centimeters enabling the proper sizing of the catheter&#39;s length for most women&#39;s urethra. The proximal end includes a proximal retention structure  15 . Proximal retention structure  15  generally functions to prevent the incontinence prevention device from moving up into the urethra and provides a means for gripping the incontinence prevention device during removal. Proximal retention structure  15  is typically configured to conform to the vestibule proximate the urethral opening. The proximal end of the shaft may also include a beveled edge  16 . Beveled edge  16  tends to prevent the spraying of urine during urination. In addition, the proximal end typically includes a structure for preventing the incontinence prevention device from tracking up the urethra. 
     Retention structure  14  comprises a closed loop at the distal end of the shaft non-concentrically disposed about shaft  12 . Retention structure  14  may be integral with shaft  12  or a separate element that is secured to shaft  12 .  FIG. 2  shows a proximal end view of device  10  of  FIG. 1  illustrating an embodiment of the non-concentric relationship of shaft  12  to retention structure  14 . Retention structure  14  projects in a general lateral direction from the shaft and is typically non-concentrically disposed about shaft  12 . Retention structure  14  is typically shaped to be received at the base of the urinary bladder and above the bladder&#39;s neck. Retention structure  14  maintains the incontinence prevention device in position as the bladder neck rises and drops with patient activity. The retention structure is thought to be maintained within the bladder as a moist watermelon seed is ejected when squeezed between one&#39;s thumb and forefinger. Thus, when the retention structure slips below the neck and into the urethra, there is a tendency for the retention structure to be forced back into the bladder as the bladder neck and/or urethra resume their original orientation. Typically, a device having a retention structure in accordance with the present invention is capable of maintaining the catheter&#39;s position regardless of the forces typically encountered. However, the device may be removed by simply pulling on the proximal end with sufficient force to collapse the retention structure. 
     The retention structure may be substantially circular, as shown in  FIG. 2 , or may have various shapes appropriate for holding device  10  within the urethra that will be recognized by those skilled in the art. The retention structure is configured to be collapsible for insertion through the urethra and to regain its shape after insertion once in the bladder. After insertion, the retention structure has sufficient rigidity to hold the retention structure within the urinary bladder. To retain its shape, the retention structure may include an internal wire or be composed of a material with sufficient memory to regain the loop configuration. 
     In addition,  FIG. 2  shows lumen  18  extending through the proximal end of shaft  12 . 
       FIG. 3  shows an alternative embodiment of the retention structure. In the embodiment of  FIG. 3 , retention structure  14  includes a protuberance  22  projecting from the loop. In addition and as discussed in more detail below, a segment  21  may be attached to shaft  12  to form the loop and to provide protuberance  22 . Protuberance  22  forms a smaller leading tip for easier insertion and helps to maintain the incontinence prevention device on a stylet during insertion. To facilitate this, protuberance  22  typically includes a lumen that is coextensive with lumen  18  of shaft  12 . That is, lumen  18  extends from a proximal end incontinence prevention device  10  to a distal end  26 . Typically, the lumen does not extend through distal end  26  but only to a point immediately proximal to distal end  26 . This configuration prevents the flow of urine through the lumen. Alternatively, the incontinence prevention device may have the lumen extending through distal end  26  to allow fluid flow through the lumen as required for some applications. When the retention structure includes a portion of the shaft, a segment  21  is typically provided to complete the loop comprising retention structure  15 . Segment  21  is typically attached at one end to a first location proximate to distal end  26  of shaft  12  and, at the segment&#39;s other end, to a second location along the shaft closer to the shaft&#39;s proximal end so as to form a loop. Typically, the length of segment  21  and the positions for its attachment are selected so as to permit the loop to assume an appropriate configuration for insertion into the urethra and subsequent reformation into a loop when in the bladder. 
     Shaft  12  and segment  21  may be configured to appear as a single unit for insertion. That is, when you straighten out the loop the two elements have the appearance of being one element. One such configuration may include configuring segment  21  as a horseshoe defining a cavity  23 , as shown in cross-section in FIG.  4 . Shaft  12  is then shaped to be received within cavity  23 . When the loop is collapsed, cavity  23  receives shaft  12  and the retention structure appears as one element instead of a separate segment  21  and shaft  12 . The actual circumference of the retention structure is therefore reduced making it physically easier to insertion and less traumatic on the patient. In addition, the thinner appearance would tend to be less intimidating to a patient. 
     The shaft and retention structure may be composed of a uniform material or may be composed of layers of material to confer the desired characteristics. When layered, the structure may include, for example, an inner layer of polyurethane surrounded by an outer layer of silicone or other combinations that confer desired characteristics. For example, the layered structures may be formed by inserting a polyurethane tube inside a silicone sleeve. The fit between the polyurethane tube and silicone sleeve is such that their contact minimizes slippage between the two. To develop sufficient contact, the silicone sleeve is typically soaked in a suitable solvent to swell the sleeve. The polyurethane tube is then inserted into the sleeve. As the solvent evaporates, the silicone sleeve contracts against the polyurethane tube. Typically, only the shaft is provided with such a silicon sleeve. 
     Using the above method of manufacture, the polyurethane tube holds the structure together while the silicone provides an appropriate surface for the sphincter to contract against. In addition, the retention structure may be integral with the shaft or formed independent of the shaft. When integral, device  10  may be formed from a single tube having its distal end wrapped around and secured to the tube to separately define the shaft and the retention structure. When formed independently, the retention structure may have a different shape and physical characteristics than the shaft. 
     The method of using a incontinence prevention device in accordance with the present invention is best understood with reference to  FIGS. 5A ,  5 B and  5 C. The figures illustrate a method of linearizing a device  10 , as shown in  FIG. 1 , for insertion into the urethra.  FIG. 5A  shows an insertion tool  30  having a handle  32  attached to a stylet  34 . Handle  32  is not required but is typically provided for better control of the catheter during insertion. Stylet  34  is composed of a material, typically a metal wire, having sufficient rigidity to facilitate the insertion of the catheter into the urethra. Stylet  34  is typically sized to fit within lumen  18  of device  10 . In use, stylet  34  is inserted into shaft  12  through lumen  18  at the shaft&#39;s distal end, as shown in FIG.  5 B. Stylet  34  is advanced into shaft  12  through lumen  18 . Once the stylet&#39;s distal end reaches retention structure  14 , retention structure  14  assumes a conformation allowing insertion through the urethra, as shown in  FIG. 5C , due to forces conferred by stylet  34 . At this point, lubrication is typically applied to device  10 . If the device is hydrogel coated, the device is lubricated simply by moistening the material. Alternatively, a water-soluble lubricant, like K-Y Jelly, or other suitable lubricant may be applied to the catheter&#39;s surface. In the embodiment shown, stylet  34  is typically advanced until retention structure  14  collapses in on itself due to the rigidity of the stylet and the tension exerted between the distal tip of stylet  30  and the point  36  where the loop attaches to shaft  12 . Thus, insertion of the stylet renders urethral catheter  14  substantially rectilinear so as to allow insertion into a urethra. Retention structure  14  is then inserted into the urethra. Once retention structure  14  of the incontinence prevention device  10  is positioned within the urinary bladder, the stylet is removed allowing retention structure  14  to resume its original configuration. The proximal end of device  10  is then manipulated, if necessary, to properly orient non-concentrically configured retention structure  14  adjacent to the bladder neck within the patient. The orientation of retention structure  14  may be reflected by reference to orientation marking  38  on shaft  12 . Thus, for example, when orientation marking  38  is oriented ventrally, retention structure  14  is properly oriented within the patient&#39;s bladder.