Abstract:
In a ureter drainage device comprising a ureteral catheter ( 10 ), a sliding hose ( 12 ) to be coupled to the proximal end of the ureteral catheter ( 10 ), and a control hose ( 18 ) to be mounted over the sliding hose ( 12 ), it is provided that the ureteral catheter ( 10 ) and the sliding hose ( 12 ) comprise mutually engaging coupling elements ( 33,38 ). At least one coupling element ( 38 ), provided on the sliding hose ( 12 ), is radially outwardly biased in the release direction and retained in the engagement position by the control hose ( 18 ) covering this coupling element ( 38 ).

Description:
The present invention relates to a ureter drainage device comprising a ureteral catheter, a sliding hose to be coupled to the proximal end of the ureteral catheter, and a control hose to be mounted over the sliding hose. 
     BACKGROUND OF THE INVENTION 
     Ureteral catheters, which are also referred to as dual J-stents or in-dwelling ureter splints, are hose-shaped aids for discharge of the urine from the renal pelvis into the urinary bladder in cases where the ureter is not sufficiently permeable anymore. The ureteral catheters which are presently in widespread use have both of their ends formed with involutions. The involution in the renal pelvis has a smaller diameter while the involution of the bladder has a larger diameter. For placing the catheters through the urethra and the bladder, use is made of a cystoscope. The involutions of the catheter have to be straightened into a linear orientation so that the catheter will fit through the cystoscope working channel. This straightening of the catheter is carried out by means of a guide wire. If the tip of the catheter comprises a closed cap, the guide wire is set from the bladder-side end. If the guide wire is already arranged in the ureter, the straightening and subsequent upward shifting of the catheter into the renal pelvis is made possible in that the catheter tip is open and of an integral conical shape. Since the ureteral catheter serves for internal splintage and its draining end region extends only to a position within the bladder, the ureteral catheter remaining within the patient&#39;s body has to be shifted off the guide wire. This is accomplished by use of a sliding hose. 
     In certain cases where the ureter follows a considerably winding course or in case of very narrow ureter stenoses, a firm but detachable connection between the urethral catheter and the sliding hose would be suitable because such a connection would allow not only for shifting but also for pulling and rotating movements of the catheter. 
     U.S. Pat. No. 4,963,129 describes a ureter drainage device with shifting hose. The shifting hose connects to the urethral catheter via a coupling device comprising two interengaging coupling elements. Securement of the coupling device in the engaged position is performed by the guide wire. When the guide wire is pulled out, the sliding hose is detached from the ureter hose. 
     EP 0 752 251 A1 describes a ureter drainage device wherein the proximal end of the ureteral catheter is connected to a sliding hose through frictional engagement. Extending in the sliding hose is a control hose adapted to be advanced for releasing the frictional engagement and separating the ureteral catheter from the sliding hose. 
     It is an object of the invention to provide a ureter drainage device wherein the ureteral catheter is reliably held in position on the sliding hose for shifting, pulling and rotating movements during advancement, irrespective of whether a guide wire has been inserted. 
     SUMMARY OF THE INVENTION 
     In the ureter drainage device according to the instant invention, the ureteral catheter and the sliding hose comprise mutually engaging coupling elements. At least one of coupling element, provided on the sliding hose, is radially outwardly biased in the release direction and is retained in the engagement position by the control hose covering said one coupling element. 
     The invention allows for the use of the present catheter placement techniques such as the Seldinger technique and the retrograde technique. Using the invention, the decoupling of the ureteral catheter from the sliding hose can be performed easily and by application of a defined force. This is effected by two mutually engaging coupling members which are held in engagement by the outer control hose. This arrangement obviates the need for an internal guide wire for fixing the two members. At least one of the coupling elements of the sliding hose is subjected to an inherent radial outward bias in its release direction while being retained by the sliding hose so as to remain engaged with the proximal end of the ureteral catheter. In this manner, pulling forces as well as shifting and rotational forces can be transmitted. To release the connection, the control hose is withdrawn on the sliding hose, causing the coupling element to spread apart under the effect of the bias and thus to release the ureteral catheter. 
     According to a preferred embodiment of the invention, it is provided that the coupling element of the sliding hose comprises at least one distally projecting leg with a hook provided on its end, and that the coupling element of the ureteral catheter is formed with a recess for receiving the hook. 
     Preferably, the coupling element of the sliding hose is formed as a barb which, when sliding on the ureteral catheter, will snap into a locked position in a recess of the catheter. This barb is of a saw-tooth design comprising an inclined flank and an upright flank. 
     According to another preferred embodiment of the invention, there is provided a handling means comprising two grip portions arranged for displacement in the longitudinal direction and being biased to move away from each other in the longitudinal direction. One of the grip portions is connected to the sliding hose and the other grip portion is connected to the control hose. The grip portions are pressed away from each other by a spring means, with the control hose being urged into the advanced position to cover and lock the coupling device. When the grip portion connected to the control hose is retracted against the spring force, the control hose will release its grip on the coupling device and thus permit disengagement thereof. This allows for easy handling and even for single-handed operation of the drainage device for disengagement of the coupling device. 
    
    
     An embodiment of the invention will be described in greater detail hereunder with reference to the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a longitudinal sectional view of the drainage device in the condition wherein the urethral catheter is being inserted into the body; 
     FIG. 2 is an enlarged view of the detail II from FIG. 1; 
     FIG. 3 is a longitudinal sectional view of the device with inserted guide wire, 
     FIG. 4 is a longitudinal sectional view of the device in the condition wherein the ureteral catheter is being detached from the sliding hose; and 
     FIG. 5 is a perspective schematic view of the coupling device. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The ureter drainage device comprises a ureteral catheter  10  which consists of a flexible hose and in the relaxed condition has both of its ends formed with an involution. In the drawings, ureteral catheter  10  is illustrated in its linear stretched condition and without these end-side involutions. 
     The proximal end of ureteral catheter  10  is connected via a coupling device  11  to a sliding hose  12  forming an extension of ureteral catheter  10 . The proximal end of sliding hose  12  is connected to a first grip member  14  and a handling device  13 . On the first grip member  14 , a second grip member  15  is arranged for longitudinal displacement. A spring  16  is provided to urge the two grip members  14  and  15  away from each other in axial directions, the movement of the second grip member  15  being delimited by a stopper  17 . 
     The second grip member  15  has a control hose  18  attached thereto which surrounds the sliding hose  12 . By moving the second grip portion  15  relative to the first grip portion  14 , the control hose  18  can displaced on the sliding hose  12 . The first grip member  14  is formed with a longitudinal channel  19  joining the lumen of the sliding hose  12  and connecting with a connecting element  20  of grip member  14 . Connecting element  20  is provided with an external thread  21  and an annular elastomeric ring  22  arranged internally of element  20 . Connecting element  20  is suited for screw-attachment of a connector piece  23  to be used for application of a syringe  24  (FIG. 1) or insertion of a guide wire  25  (FIG.  3 ). 
     The first grip member  14  comprises a radially projecting grip  26  and the second grip member  15  likewise comprises a radially projecting grip  27 . By pulling the grip  27  toward the grip  26 , the control hose  18  can be pulled back on the sliding hose  12 . 
     FIG. 2 is an enlarged partial view showing the coupling device  11 . Coupling device  11  comprises a first coupling piece  30  having a tubular projection  31  extending into and fixed within ureteral catheter  10 . Tubular projection  31  is joined by a larger-diametered headpiece  32  provided with two diametrically opposed recesses  33 . Longitudinal guide grooves  34  are formed to lead into these recesses  33  as shown in FIG.  5 . 
     Inserted in the distal end of sliding hose  12  is a coupling member  35  comprising a tubular projection  36  and a headpiece  37  arranged externally of sliding hose  12 . The headpiece  37  has two legs  38  extending therefrom, each provided with a hook  39  on its free end. The hooks  39  are each formed with an inclined flank  40  and an upright flank  41 . The hooks  39  are biased outwardly, i.e. they tend to spread apart according to FIG.  5 . When the coupling members  30 , 35  are shifted onto each other for mutual engagement as illustrated in FIG. 2, the hooks  39  will enter the recesses  33  at the time that the control hose  18  exerts a force pressing the legs  38  inwardly. Conversely, when the control hose  18  is pulled back, the legs  38  will spread apart and the hooks  39  will leave the recesses  33 . For this purpose, the coupling device  11  is given a bias in the release direction. 
     FIG. 1 shows the ureteral catheter  10  after having been coupled to the sliding hose  12  by means of the coupling device  11 . In this situation, control hose  18  is already in an advanced position, thus covering the elastic legs  38  and securing them in the locked condition. 
     As illustrated in FIG. 3, the guide wire  25  is inserted through connector piece  23  and handling device  13  into sliding hose  12  and ureteral catheter  10 , so that the latter is straightened to assume a linear orientation. Subsequently, the guide wire  25  can be fixed in the predetermined position within the handling device  13  by screwing the connector piece  23  tightly into place. Thereby, the elastomeric ring  22  is axially compressed with a resultant decrease of the size of its opening, so that the guide wire  25  is clamped in position in the elastomeric ring  22 . In this manner, the connector piece  23  acts also as a tensioning means for clamping the guide wire  25 . 
     In the condition shown in FIG. 3, the device is inserted into the patient&#39;s body through a cystoscope while the ureteral catheter  10  is placed in the ureter. Then, as shown in FIG. 4, the handling device  13  is actuated by pulling the second grip member  15  toward the first grip member  14 , thus tensioning the spring  16 . Thereby, the control hose  18  is pulled back to release the coupling device  11  and cause the legs  38  to spread outward in a self-acting manner. Now, the handling device  13  can be pulled back together with sliding hose  12  and control hose  18  while the ureteral catheter  10  will remain in the ureter. 
     Should the placement of the catheter be performed without use of a guide wire  25 , an X-ray contrast medium can be introduced into sliding hose  12  and ureteral catheter  10  by use of the syringe  24 , so that the placing of the catheter can be controlled in the X-ray picture. 
     Instead of inserting the guide wire  25  subsequently, it is also possible, by way of alternative, to first insert the guide wire into the patient&#39;s body and then to shift the above described device over the guide wire.