Abstract:
A catheter assembly suitable for intermittent catheterization comprising a cylindrical casing composed of two telescopically moveable parts one of which is connectable to and moveable with a piston which is rigidly connected to a urinary catheter. The interior of the cylindrical casing is filled with a lubricating, anesthetic, antiseptic liquid, or the like, which during catheterization is injected into the urethra and urinary bladder through the catheter under the effect of movement of the piston simultaneously with the insertion of the catheter into the urethra. The device is provided with an anti-infective cap which is inserted into the first third of the urethra and is used as a guide for inserting the catheter into the urethra without physical contact with the part if the urethra which is a harbor of infections.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to the field of urology, in particular to a compact ready-to-use catheter assembly with means for injection of a therapeutic liquid into the urethral channel. The catheter of the invention is a female catheter most suitable for intermittent self-catheterization. 
       DESCRIPTION OF PRIOR ART 
       [0002]    Intermittent catheterization may be necessary for patients who are unable to completely empty the urinary bladder during urination or unable to naturally urinate by themselves temporarily or permanently. Such a condition is known as “urinary retention.” Intermittent catheterization may also be required, e.g., to obtain a sterile urinary specimen from a patient in a doctor&#39;s office. 
         [0003]    Intermittent catheterization involves the temporary placement of a catheter through the urethra to the bladder for emptying the latter. A goal of intermittent catheterization is to prevent urinary-tract infection by completely emptying the urinary bladder since accumulation of urine in the bladder over a long period of time may create conditions for development of a urinary-tract infection. After a bladder is effectively drained, urinary-tract infections cease to be a problem, and the kidneys are safeguarded. 
         [0004]    Urinary catheters supplied for intermittent catheterization in general must have a lubricant applied to the outer surfaces thereof to facilitate insertion into the urethra. For example, hydrophilic urinary catheters have a hydrophilic outer surface coating that should be wetted with fluid such as water or a saline solution for a certain time period before insertion thereof into the urethra of a patient for lubrication purposes. 
         [0005]    Various methods for lubricating urinary catheters have been previously proposed, examples of which are given below. 
         [0006]    U.S. Pat. No. 5,209,726 makes known a self-lubricating urinary catheter and a method for self-catheterization. The catheter has an annular lubricant reservoir surrounding an inner tube having perforations. As the catheter is inserted into the urethra of a patient, the lubricant is forced from the reservoir into the inner tube and out and into the urethra through a discharge outlet in the catheter. Lubrication of the outer surface of the catheter, therefore, takes place only as the catheter is being inserted into the urethra of the patient, resulting in at least some initial discomfort for the patient on insertion of the catheter. 
         [0007]    U.S. Pat. No. 3,967,728 makes known a catheter package comprising a urinary catheter and a rupturable, lubricant-containing pouch. One edge of the pouch is located within the package adjacent to the tip of the catheter, and the seal at that edge is constructed so that it ruptures when the pouch is squeezed in order to lubricate the tip of the catheter. Because only the tip of the catheter is lubricated, the patient still suffers discomfort on insertion of the catheter into the urethra. 
         [0008]    U.S. Pat. No. 7,066,912 issued in 2006 to Nestenborg, et al., describes a wetting apparatus for wetting a hydrophilic urinary catheter comprising a wetting-fluid container that holds a wetting fluid and that can be opened by application of a pulling force thereto; a wetting receptacle; and a hydrophilic urinary catheter to be wetted by said wetting fluid and being arranged within said wetting receptacle. The wetting-fluid container is arranged within the wetting receptacle, and the wetting receptacle is extendable for opening the wetting container without rupturing the sealed portion of the wetting receptacle. 
         [0009]    However, the devices described above are not available in a compact form, i.e., in a ready-to-use form, and therefore are inapplicable for self-catheterization and inconvenient for storage. 
         [0010]    An example of a catheter that solves the above problems is a compact urinary prepackaged catheter developed by Coloplast Company (Denmark) and known under the trademark SpeediCath™, which can be obtained in a sterile and ready-to-use prehydrated form right out of the package. Each SpeediCath™ is prepackaged in sterile saline solution and in a plastic container that can be taken anywhere, similar to a ballpoint pen. Since SpeediCath™ is prelubricated, its coating is always optimally hydrated to be slippery and comfortable. 
         [0011]      FIG. 1  is a longitudinal sectional view of the SpeediCath™ urethral catheter assembly for self-catheterization shown in a longitudinal section. The catheter assembly, which as a whole is designated by reference numeral  20 , has a compact construction and consists of two casing parts  22  and  24  and a catheter unit  26  that is hermetically sealed inside the casing part  24 . More specifically, the casing part  22  comprises a cylindrical sleeve with an open front end and a perforated bottom  28 . The second casing part  24  comprises a tubular body, one end of which is closed and forms a handle  32  and a portion  34  which is opposite to the handle  32 , is telescopically inserted into the open end of the casing part  22 , and is closed by a holder  36  that holds a catheter  38  that extends in the axial direction X-X of the catheter assembly  20  into the interior of the second casing part  24  almost to the bottom of its central opening. The holder  36  has a first shoulder  39  ( FIG. 1 ) and a second shoulder  40  to which the end face of the portion  34  of the second casing part  24  is sealed and strongly attached, e.g., by adhesion or thermal bonding so that a space  42  is formed among the inserted part of the holder  36 , the outer surface of the catheter  38 , and the inner surface of the second casing part  24 . The area  37  of the sealed adhesive or bonding connection between the shoulder  40  of the holder  36  and the end face of the portion  34  is the area of subsequent separation of the second casing part  24  from the catheter unit formed by the portion  34 , the holder  36 , and the catheter  38 , which will be described later. An annular groove  43  is formed between the shoulders  37  and  39 . 
         [0012]    In order to seal the space  42  in the closed state of the catheter assembly  20  shown in  FIG. 1  and used for storage, the perforated bottom  28  of the casing part  22  has a small central plug  44  which is inserted into the rear opening of the holder that is connected to the central canal of the catheter  38 , while the shoulder  40  of the holder  36  closes the perforations  46  and  48  in the bottom  28  of the casing part  22 . 
         [0013]    The surface of the catheter  38  has a hydrophilic coating and is preserved in an easy-to-insert prelubricated form by filling the sealed space  42  with a sterile physiological solution L in which the catheter  38  is retained during storage of the catheter assembly. Reference numeral  50  designates an opening in the side wall at the distal end of the catheter for discharge of urine into the interior of the catheter  38  and out from the catheter when the distal end of the catheter is inserted into the urinary bladder (not shown) for emptying the bladder through the catheter. 
         [0014]    In the casing part  24 , the portion  34  that is telescopically inserted into the open end of the casing part  22  has a diameter smaller than the remaining portion of the casing part  24  so that a shoulder  52  is formed on the casing part  24  that is butt contact with the mating end face  25  of the casing part  22 . On a significant part of its length, the outer surface of the catheter assembly  20  is coated with a thin plastic film  54  for additional sealing of the area of the aforementioned contact in order to secure the connection. 
         [0015]    For use, the plastic film  54  is torn off and removed. The casing part  22  is grasped by one hand, while the casing part  24  is pulled in the direction of arrow A ( FIG. 1 ). Since the holder  36  is strongly attached by adhesion or thermal bonding to the end face of the portion  34  of the casing part  24  at the area  37 , movement of the casing part  24  pulls the holder  36  in the same direction together with catheter, whereby the holder slides inside the casing part  22  in the direction of arrow A. This movement continues until the holder  36  reaches the end of the casing part  22  and assumes the position shown in  FIG. 2 . At this moment, a predeformed front edge  56  of the casing part  22  snaps into the annular groove  43  formed between the first shoulder  39  and a second shoulder  40  and is firmly secured to the casing  22 . 
         [0016]    The telescopic portion  34  of the casing part  24  is now withdrawn to its full length from the casing part  22 . The user, while still grasping the casing part  22 , now twists the casing part  24  with a force sufficient to disconnect the portion  34  from the shoulder  40  at the bonding area  37 , whereby the condition shown in  FIG. 2  is obtained. The disconnected casing part  24  is discarded, the interior of the space  42  is unsealed, and the liquid is poured out. 
         [0017]    As a result, as shown in  FIG. 3 , the catheter  38  pretreated with the appropriate liquid is exposed, the casing part  22  forms a catheter handle convenient for manipulating the catheter  38 , and the perforations  46  and  48  are opened for discharge of urine when the distal end of the catheter is inserted into the urinary bladder. 
         [0018]    Although the SpeediCath™ catheter assembly described above provides a catheter in a ready-to-use form and in a sterile state, it does not guarantee prevention of infection that can be introduced into the urethra during insertion unless the urethral meatus has been thoroughly cleaned before catheterization. Unfortunately, means for cleaning the meatus are not always readily available under conditions wherein self-catheterization is performed. 
         [0019]    A device that may partially solve the above-stated problem is a urinary plug for use in female patients described in U.S. Pat. No. 5,806,527 issued in 1998 to G. Borodulin, et al. Although the device is not intended for catheterization but rather for preventing involuntary release of urine from the bladder, the device is equipped with an infection-protective cap fitted on the distal end of the plug&#39;s tubular body insertable into the urinary bladder through the urethra. First, the infection-protective plug is inserted into the front infectious portion of the urethra, and then the plug is guided through the infection-protective cap without contacting the infectious part of the urethra. 
         [0020]    A similar principle of protection against introduction of infection into the urinary bladder is used in a catheter for use in female patients for self-catheterization described in U.S. Pat. No. 6,544,240 issued in 2003 to Borodulin, et al. The device has a sterile infection-protective cap slidingly fitted onto the distal end of said catheter. The cap has a slit on its distal end for possibility of pushing the catheter through the sterile tip into the bladder without physical contact of the catheter with the infectious front part of the urethra. 
         [0021]    However, the devices of U.S. Pat. No. 5,806,527 and U.S. Pat. No. 6,544,240 do not have any means that would pretreat the urethra or facilitate introduction of a plug or catheter into the bladder by treating the urethra during catheterization, e.g., by lubricating the urethral channel, etc. Furthermore, although the SpeediCath™ catheter assembly contains a sterile liquid, this liquid is intended only for treating the surface of the catheter and is not intended for treatment of the urethra. 
         [0022]    In their earlier U.S. patent application Ser. No. ______, the applicants described a compact ready-to-use urethral catheter assembly suitable for intermittent self-catheterization which comprises a tubular body filled with a therapeutic liquid for introduction into the urethra. This liquid may comprise a lubricant, an anesthetic solution, an antiseptic solution, or a therapeutic solution to pretreat the urethra during catheterization. The device has a urinary catheter with a piston portion slidingly installed into the tubular body so that catheterization is accompanied by automatic injection of the therapeutic liquid into the urethra by means of the piston through a gap formed during catheterization between the outer surface of the catheter and the inner walls of the anti-infective cap which is used as a sterile guide for insertion of the catheter without contacting the initial part of the urethra, which may harbor infection. In addition to the above, the assembly is provided with built-in means for cleaning the urethral meatus before catheterization. 
         [0023]    However, in the compact form in which it is stored, the catheter assembly described in U.S. patent application Ser. No. ______ is longer than the similar SpeediCath™ catheter assembly described above. The catheter is longer because in the aforementioned patent application, the proximal end of the plunger that is made integrally with the piston and catheter projects from the proximal end of the tubular body. 
         [0024]    Another disadvantage of the SpeediCath™ catheter assembly relates its preparation for use, during which time a part of the tubular body is separated and must be discarded, while the remaining part is used for catheterization and is discarded after the procedure. Separate discarding of two parts of the SpeediCath™ catheter assembly is not always convenient, e.g., when a patient performs self-catheterization in other than her own home, etc. Moreover, in the SpeediCath™ catheter assembly, a thin coating film that must be removed prior to use of the device seals the area of separation of two parts of the tubular body. Provision of this film makes the device less convenient for use and spoils appearance of the assembly. 
       OBJECTS AND SUMMARY OF THE INVENTION 
       [0025]    It is an object of the present invention to provide a urethral catheter for self-catheterization that incorporates advantages of both the catheter assembly of U.S. patent application Ser. No. ______ and the SpeediCath™ catheter assembly. In other words, it is an object of the invention to provide a compact ready-to-use catheter for intermittent catheterization that is small in size, is provided with a sterile cap for guiding the catheter into the urethra without contacting the urethral walls in the first part thereof, and contains a therapeutic liquid that is automatically introduced into the urethra during catheterization. It is another object to provide a compact ready-to-use catheter for intermittent catheterization that can be conveniently discarded as a single indivisible piece after use. It is a further object to provide the aforementioned catheter assembly as a catheter assembly that does not require a coating film on the outer surface of its tubular body. Another object is to provide the aforementioned catheter with an adjustable mirror to facilitate the patient&#39;s ability to locate the position of the entrance into the urethra. A further object is to provide the aforementioned catheter assembly with a mechanism of locking for connecting the outer cylindrical casing to the inner tubular portion at the end of the piston stroke when the distal end of the catheter extends to its full length for employing the catheter assembly without the self-contained liquid and for using the interlocked outer and inner casing portions as an integral handle. 
         [0026]    The urethral catheter of the invention consists essentially of an outer cylindrical casing, an inner tubular portion telescopically inserted into the outer cylindrical casing, a piston slidingly installed in the inner tubular portion and rigidly connected to the catheter, an anti-infective cap attached to the distal end of the outer cylindrical casing, a protective cover that covers the anti-infective cap in order to maintain its sterile condition, and a therapeutic liquid that fills the interior of the inner tubular portion between the piston and the anti-infective cap. 
         [0027]    The aforementioned liquid may comprise an anesthetic liquid, lubricating liquid, antiseptic liquid, a physiological solution, or any other liquid that may be required for treating the urethra or the urethral bladder. The outer cylindrical casing has an open proximal end and a closed distal end with a central opening for passage of the catheter. On its proximal end, the outer cylindrical casing has an inwardly projecting edge. 
         [0028]    The inner tubular portion has an elongated distal end that is telescopically and slidingly inserted into the outer cylindrical casing and a shorter and larger-in-diameter proximal or handle portion that is used as a handle that can be grasped by the user to move the inner tubular portion relative to the outer cylindrical casing. When the catheter assembly is in a compact or storage condition, a first shoulder that is formed on the front end of the handle portion is in butt contact with the aforementioned open proximal end of the outer cylindrical casing. The distal end of the inner tubular portion is open and has an inwardly projecting edge. In order to facilitate flexible deformation of this edge, it may be provided with short longitudinal cuts. The inner tubular portion also has on its outer surface a reduced-diameter portion that extends from the first shoulder to a second shoulder that is formed on the outer surface of the inner tubular portion at some distance from its distal end face. For convenience of grasping, the handle portion may have a flange. 
         [0029]    The piston, which is slidingly installed in the inner tubular portion and is rigidly connected to the catheter, has a proximal or rear part that has a sliding fit inside the inner tubular portion, a distal or front part that has a diameter smaller than the rear part, and an annular groove between the rear part and the front part of the piston for snapping engagement with the aforementioned inwardly projecting edge on the distal end of the inner tubular portion. Where appropriate in the context of the present invention, the term “front” designates the distal end, and the term “rear” designates the proximal side or end of the catheter assembly or a respective part thereof. 
         [0030]    A urethral catheter (that as a conventional one, comprises a thin tubular element with a length sufficient for passing through the patient&#39;s urethra to the urinary bladder) is rigidly attached to the front end of the piston, has a short front portion of a larger diameter and a long rear portion of a smaller diameter that extends from the front portion of the larger diameter to the front end face of the piston. 
         [0031]    The anti-infective cap has a flange portion for attachment to the front end of the outer cylindrical casing and an axially extended cylindrical portion with a rounded front end having a length and diameter sufficient and suitable for insertion into the first third part of the urethra, which, as is known, can be a harbor of infection. The anti-infective cap has an inner cavity into which is inserted the aforementioned front portion of the catheter that has a larger diameter and that sealingly passes through the aforementioned opening formed in the closed front end of the outer cylindrical casing. As a result, in a closed, compact, and storage state, the urethra-treatment liquid that fills the interior of the inner tubular portion is sealed in a space defined by the inner surface of the inner tubular portion, the outer surface of the catheter, the front catheter portion of a larger diameter, and the front end face of the piston. The large-diameter portion of the catheter has a transverse opening for release of urine from the urinary bladder that communicates with the axial channel that passes from the aforementioned transverse opening through the catheter, the piston portion, and further through the open rear end of the handle portion for release of urine to the outside the catheter assembly. If necessary, the rear end of the handle portion may have a tubular extension to connect the catheter assembly to a conventional urine-collecting bag, etc. 
         [0032]    The front, rounded end of the anti-infective cap has a slit for passing the catheter into the urethra. The front end of the outer cylindrical casing has an external thread for attaching the protective cover, which is screwed onto the aforementioned external thread to protect the anti-infective cap from contamination and to maintain its sterile condition. The sterile anti-infective cap can be prelubricated. 
         [0033]    If necessary, the catheter assembly of the invention may be provided with a mirror device that may facilitate finding of the urethral opening. The mirror device may comprise a U-shaped body with a mirrored inner surface for folding onto the outer surface of the outer cylindrical casing and spring-loaded legs that can be snapped in the longitudinal slot formed on the external surface of the outer cylindrical casing with the possibility of pivotally adjusting the angular position of the mirror and moving the mirror in the longitudinal direction to find the position most convenient for observation. If necessary, the mirror device may have a flat mirror portion that can be intended for multiple uses, with the rest of the catheter assembly being disposable. 
         [0034]    In order to prepare the catheter assembly for catheterization, the catheter assembly is converted from the catheter-hidden, or storage condition, to the working, or catheter-extended condition. For this purpose, the user, who may be a patient or one of the medical personnel, grasps the outer cylindrical casing with one hand, grasps the handle portion of the inner tubular portion with the other hand, and pulls out the inner tubular portion away from the outer cylindrical casing until the inwardly projecting edge on the front end of the inner tubular portion snaps into the annular groove formed on the outer surface of the piston. As a result, the piston and catheter become integrally connected to the inner tubular portion. In this condition, the urethra-treatment liquid remains sealed in the interior of the outer cylindrical casing between the front end of the outer cylindrical casing, the large-diameter portion of the catheter, the outer surface of the reduced-diameter portion of the catheter, the front end face of the piston, and the front end face of the inner tubular portion. 
         [0035]    For catheterization, the protective cover is disconnected from the outer cylindrical casing, and the anti-infective cap is inserted into the urethra, if necessary, with the use of the mirror device. As in the above condition, the catheter is rigidly connected to the assembly of the piston with the inner tubular portion, the latter is shifted forward relative to the outer cylindrical casing so that the piston slides inside the outer cylindrical casing and displaces the liquid into the urethra and further to the bladder through the gap that is now formed between the outer surface of the small-diameter portion of the catheter and the inner walls of the central opening in the anti-infective cap. The liquid flows directly to the urethra since the front end of the flange of the anti-infective cap is tightly pressed against the area of the body around the urethral meatus (the entrance into the urethra). At the end of the piston stroke, the catheter is extended to its extreme outer position, in which the urine-release opening provided on the large-diameter portion is located inside the urinary bladder. This allows empting of the bladder. Thus, introduction of the catheter into the urethra occurs simultaneously with injection of the therapeutic liquid that can be used as a lubricant, anesthetic liquid, antiseptic liquid, or the like. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0036]      FIG. 1  is a longitudinal sectional view of a known urethral catheter assembly for intermittent catheterization in the closed and compact state. 
           [0037]      FIG. 2  is a longitudinal sectional view of the urethral catheter of  FIG. 1  in the condition wherein the first part of the casing is separated from the second part, and a predeformed front edge of the second part snaps into the annular groove of the catheter holder. 
           [0038]      FIG. 3  is a longitudinal sectional view of the catheter of  FIG. 1 , with the catheter extended from the casing and ready for use. 
           [0039]      FIG. 4  is a longitudinal sectional view of the urethral catheter assembly of the present invention in the closed and compact state with the urethra-treating liquid sealed inside the catheter casing. 
           [0040]      FIG. 5  is a longitudinal sectional view of the urethral catheter of  FIG. 4  in the condition wherein the inner tubular portion is withdrawn and the edge of the outer casing snaps into the grooves of the piston. 
           [0041]      FIG. 6  is a longitudinal sectional view of the catheter assembly of  FIG. 4  during catheterization, with the catheter inserted into the urethra in a fully extended position. 
           [0042]      FIG. 7  is a three-dimensional view of the distal end of the catheter of the invention equipped with a mirror in the working position. 
           [0043]      FIG. 8  is a side view of the distal end of the catheter of  FIG. 7  with the mirror in the folded position. 
           [0044]      FIG. 9  is a sectional view of the proximal part of the catheter assembly of the invention that shows a tubular extension for connection of the catheter assembly to a urine collector. 
           [0045]      FIG. 10  is a three-dimensional view illustrating a modification of the catheter assembly of the invention which is provided with a mechanism for locking the outer cylindrical casing to the inner tubular portion at the end of the piston stroke when the distal end of the catheter extends to its full length. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0046]    The invention will now be described in more detail with reference to accompanying drawings. 
         [0047]      FIG. 4  is a longitudinal sectional view of the urethral catheter assembly of the present invention which in general is designated by reference numeral  120  and is shown in a closed and compact state in which is it stored with a therapeutic liquid L sealed inside the urethral catheter assembly  120 . 
         [0048]    The urethral catheter  120  of the invention consists essentially of an outer cylindrical casing  122 , an inner tubular portion  124  telescopically inserted into the outer cylindrical casing  122 , a piston  126  slidingly installed in the inner tubular portion  124  and rigidly connected to the catheter  128 , an anti-infective cap  130  attached to the distal end  122   a  of the outer cylindrical casing  122 , a protective cover  132  that covers the anti-infective cap  130  in order to maintain its sterile condition, and the aforementioned therapeutic liquid L, which, in the storage state of the assembly shown in  FIG. 4 , fills the interior of the inner tubular portion  124  between the piston  126  and the anti-infective cap  130 . 
         [0049]    The aforementioned liquid L may comprise an anesthetic liquid, lubricating liquid, antiseptic liquid, a physiological solution, or any other liquid that may be required for treating the urethra or the urethral bladder. The outer cylindrical casing  122  has an open proximal end  122   b , while the aforementioned distal end  122   a  is closed but has a central opening  122   c  for passage of the catheter  128 . On its proximal end  122   b , the outer cylindrical casing  122  has an inwardly projecting edge  122   d.    
         [0050]    The inner tubular portion has an elongated distal end  124   a  that is telescopically and slidingly inserted into the outer cylindrical casing  122  and a shorter and larger-in-diameter proximal or handle portion  124   b  that is used as a handle that can be grasped by the user to move the inner tubular portion  124  relative to the outer cylindrical casing  122 . 
         [0051]    When the catheter assembly  120  is in a compact or storage condition shown in  FIG. 4 , a first shoulder  124   c  that is formed on the front end of the handle portion  124   b  is in butt contact with the aforementioned open proximal end  122   b  of the outer cylindrical casing. The distal end  124   a  of the inner tubular portion is open and has an inwardly projecting edge  124   d . In order to facilitate flexible deformation of this edge, it may be provided with short longitudinal cuts (not shown in the drawing). The inner tubular portion also has on its outer surface a reduced-diameter portion  124   e  that extends from the first shoulder  124   c  to a second shoulder  124   f  that is formed on the outer surface of the inner tubular portion  124  at some distance from the inwardly projecting edge  124   d . For convenience of grasping, the handle portion  124   b  may have a flange  124   g.    
         [0052]    The piston  126 , which is slidingly installed in the inner tubular portion  124  and is rigidly connected to the catheter  128 , has a proximal or rear part  126   a  that has a sliding fit inside the inner tubular portion  124 , a distal or front part  126   b  that has a diameter smaller than the rear part  126   a , and an annular groove  126   c  between the rear part  126   a  and the front part  126   b  of the piston for snapping engagement with the aforementioned inwardly projecting edge  124   d  on the distal end of the inner tubular portion  124 . Where appropriate in the context of the present invention, the term “front” will designate the distal end, and the term “rear” will designate the proximal side or end of the catheter assembly  120  or a respective part thereof ( FIG. 4 ). 
         [0053]    A urethral catheter  128  (that as a conventional one, comprises a thin tubular element with a length sufficient for passing through the patient&#39;s urethra to the urinary bladder) is rigidly attached to the front end of the piston  126 , has a short front portion  128   a  of a larger diameter and a long rear portion  128   b  of a smaller diameter that extends from the front portion  128   a  of the larger diameter to the front end face of the piston  126  ( FIG. 4 ). 
         [0054]    The anti-infective cap  130  has a flange portion  130   a  for attachment to the front end  122   a  of the outer cylindrical casing  122  and an axially extended cylindrical portion  130   b  ( FIG. 4 ) with a rounded front end having a length and diameter sufficient and suitable for insertion into the first third part of the urethra, which, as is known, can be a harbor of infection. The anti-infective cap has an inner cavity inserted into which is the aforementioned front portion  128   a  of the catheter  128  that has a larger diameter and that sealingly passes through the aforementioned opening  122   c  formed in the closed front end  122   a  of the outer cylindrical casing  122 . As a result, in a closed, compact, or storage state, the urethra-treatment liquid L that fills the interior of the inner tubular portion  124  is sealed in a space defined by the inner surface of the inner tubular portion  124 , the outer surface of the catheter  128 , the front catheter portion  128   a  of a larger diameter, and the front end face of the piston  126 . The large-diameter portion  128   a  of the catheter has a transverse opening  128   c  for release of urine from the urinary bladder that communicates with the axial channel  128   d  ( FIG. 4 ) that passes from the aforementioned transverse opening through the catheter, the piston portion, and further through the open rear end of the handle portion  124   b  for release of urine to the outside the catheter assembly  120 . 
         [0055]    The front, rounded end on the cylindrical part  130   b  of the anti-infective cap  130  has a slit  130   c  ( FIG. 4 ) for passing the catheter  128  into the urethra. The front end  122   a  of the outer cylindrical casing  122  has an external thread  122   e  for attaching the protective cover  132 , which is screwed onto the aforementioned external thread  122   e  to protect the anti-infective cap  130  from contamination and to maintain its sterile condition. The sterile anti-infective cap  130  can be prelubricated. 
         [0056]    In order to prepare the catheter assembly  120  for catheterization, the catheter assembly  120  is converted from the catheter-hidden, or storage condition shown in  FIG. 4 , to the extended position shown in  FIG. 5  ready for insertion into the urethra and for injection of the liquid L into the urethra and urinary bladder. For this purpose, the user, who may be a patient or one of the medical personnel, grasps the outer cylindrical casing  122  with one hand, grasps the handle portion  124   b  of the inner tubular portion  124  with the other hand, and pulls out the inner tubular portion  124  away from the outer cylindrical casing  122  until the inwardly projecting edge  124   d  on the front end of the inner tubular portion  124  snaps into the annular groove  124   c  formed on the outer surface of the piston  126 . As a result, the piston  126  and the catheter  128  become integrally connected to the inner tubular portion  124 . In this condition, the urethra-treatment liquid L remains sealed in the interior of the outer cylindrical casing  122  between the front end  122   a  of the outer cylindrical casing  122 , the large-diameter portion  128   a  of the catheter  128 , the outer surface of the reduced-diameter portion  128   b  of the catheter  128 , the front end face of the piston part  126   b , and the front end face of the inner tubular portion  124 . 
         [0057]    For catheterization, the protective cover  132  is disconnected from the outer cylindrical casing  122 , and the anti-infective cap  130  is inserted into the urethra (as shown in  FIG. 6 ). As the catheter  128  is rigidly connected to the assembly of the piston  126  with the inner tubular portion  124 , the latter is shifted forward relative to the outer cylindrical casing  122  so that the piston  126  slides inside the outer cylindrical casing  122  and displaces the liquid L into the urethra U and further to the urinary bladder B ( FIG. 6 ) through the gap G that is now formed between the outer surface of the small-diameter portion  128   b  of the catheter  128  and the inner walls of the central opening in the anti-infective cap  130 . The liquid L flows directly to the urethra U since the front end of the flange  130   a  of the anti-infective cap  130  is tightly pressed against the area of the body BD around the urethral meatus (the entrance into the urethra). At the end of the piston stroke, the catheter  128  is extended to its extreme outer position shown in  FIG. 6 , in which the urine-release opening  128   c  provided on the large-diameter portion  128   a  is located inside the urinary bladder B. This allows empting of the bladder B. Thus, introduction of the catheter  128  into the urethra U occurs simultaneously with injection of the therapeutic liquid L that can be used as a lubricant, anesthetic liquid, antiseptic liquid, or the like. 
         [0058]    If necessary, as shown in  FIGS. 7 and 8 , the catheter assembly  120 ′ of the invention may be provided with a mirror device  121  that may facilitate finding of the urethral opening. The mirror device  121  may comprise a U-shaped body with a mirrored inner surface  121   a  for folding onto the outer surface of the outer cylindrical casing  122 ′ and spring-loaded legs  121   b   1  and  121   b   2  that can be snapped into the longitudinal slots (only one of which  121   c  is shown in  FIGS. 7 and 8 ) formed on the external surface of the outer cylindrical casing  122 ′ with the possibility of pivotally adjusting the angular position of the mirror  121  and moving the mirror  121  in the longitudinal direction along the slots to find the position most convenient for observation. If necessary, the mirror device  121  may have a flat mirror portion (not shown) that can be intended for multiple uses, with the rest of the catheter assembly being disposable. Reference numeral  128 ′ designates the catheter. 
         [0059]    As shown in  FIG. 9 , the rear end of the handle portion  124   b  may have a tubular extension  125  for connection of the catheter assembly to a conventional urine-collecting bag, etc. 
         [0060]      FIG. 10  shows a modification of the catheter assembly  120 ″ which is provided with means for locking the outer cylindrical casing  122 ″ to the inner tubular portion  124 ″ in the extended condition of the catheter  128 ″ shown in  FIGS. 6 and 10  for using the extended catheter  128 ″ as a conventional one and for using the outer cylindrical casing  122 ″ interlocked with the inner tubular portion  124 ″ as a handle. In this case, when the urinary catheter  128 ″ is moved forward, the liquid is expelled from the interior of the catheter assembly onto the outer surface of the urinary catheter  128 ″ and pre-lubricate the latter so that after urinary catheter is shifted into the most extended position, the outer cylindrical casing  122 ″ is fixed to the inner tubular portion  124 ″, and the pre-lubricated catheter can be used for catheterization while the fixed parts of the casing can be used as a handle. 
         [0061]    The aforementioned locking means comprises a bayonet-type lock formed by an L-shaped slot  123  formed on the proximal end of the outer cylindrical casing and a pin  125  projecting radially outward from the surface of the inner tubular portion  124 ″ just in front of the handle portion  124   b″.    
         [0062]    If necessary, the construction shown in  FIG. 10  makes it possible to use the catheter assembly without filling the interior of the outer cylindrical casing  122 ″ with therapeutic liquid L. When the urinary catheter  128 ″ is extended to its full length, it is pre-lubricated, and then is used for catheterization. 
         [0063]    Thus it has been shown that the present invention provides a urethral catheter assembly for self-catheterization that has a compact ready-to-use construction, is suitable for intermittent catheterization, is small in size, is provided with a sterile cap for guiding the catheter into the urethra without contacting the urethral walls in the first part thereof, and contains a therapeutic liquid that is automatically introduced into the urethra during catheterization. The catheter assembly of the invention can be conveniently discarded as a single indivisible piece after use, does not require a coating film on the outer surface of its tubular body, and can be equipped with an adjustable mirror to facilitate the patient&#39;s ability to locate the position of the entrance into the urethra.