Abstract:
A urological resectoscope ( 1 ) including a main body ( 2 ) that is traversed by an optics ( 9 ) and to which the guide ( 4 ) of a carriage ( 6 ) is affixed proximally and to which are mounted an inner shaft ( 15 ) and an outer shaft ( 16 ). The inner and outer shaft both extend distally from the main body. The outer shaft ( 16 ) encloses the inner shaft ( 15 ) and is detachable from the main body via an externally actuated outer connector element ( 17 ). The outer connector element ( 17 ) is connected to the main body ( 2 ).

Description:
BACKGROUND OF THE INVENTION  
       [0001]     For decades already resectoscopes have been the backbone of urological instrumentation. For permanent rinsing they comprise an inner and an outer shaft, rinsing fluid being fed from the inner shaft and then being evacuated through the annular space between said shafts. The outer shaft is detachable by means of an externally actuated connector element. The optics monitoring the surgery zone, and the implement operational therein, for instance the conventional high-frequency (hf) cutting loop, run through the inner shaft.  
         [0002]     Regarding known resectoscopes of the species described in U.S. Pat. Nos. 5,807,240 and 5,486,155, the inner shaft also is detachable by means of an externally actuated connector element. The connector elements for the outer and inner shafts hereafter are called external connector element and inner connector element, respectively. In known resectoscopes, the inner connector element also is actuated externally and it directly engages the resectoscope main body, whereas the outer connector element engages the inner connector element. It is furthermore known to make the outer connector element rotatable relative to the entire remaining resectoscope, including the inner shaft.  
         [0003]     One of the main problems encountered in resectoscopes is the available length of the shaft that can be inserted into the typical human body. The length should be as large as possible whereas the total resectoscope length should be minimized in order to minimize, for instance, the optics which extend the length of the resectoscope and for optical reasons should be as short as possible. Accordingly, designers in this field attempt foremost to maximize the shaft length while reducing resectoscope length elsewhere, but difficulties arise.  
         [0004]     The design of known resectoscopes comprising two externally actuated connector elements, inherently limits the available shaft length.  
       BRIEF SUMMARY OF THE INVENTION  
       [0005]     The objective of the present invention is to create a resectoscope of simple design offering greater available shaft length.  
         [0006]     In the present invention, the outer connector element directly engages the resectoscope main body. On the other hand no external connector element is used to actuate the inner connector element and as a result, contrary to the case of conventional design, the length of one externally driven connector element, namely a minimum of about 5 mm, may be saved and, keeping the total resectoscope length constant, the available outer shaft length may be increased. This feature is of substantial advantage to the surgeon. The outer connector element directly engages the resectoscope main body. In this manner, that is circumventing external action on parts of an inner connector element placed at the resectoscope periphery, the connection zone may be shortened. The inner shaft in this design is affixed within the outer connector element.  
         [0007]     The inner shaft may be affixed to the resectoscope main body, preferably in a permanent manner. This very simple design entirely circumvents the known inner connector element.  
         [0008]     By providing an inner connector element to remove the inner shaft, conventional instrument cleansing can be improved. The inner connector element may exhibit a variety of designs, for instance being a screw connection, bayonet connection, snap-in connection with elastic tongues or the like. The inner connector element need not exert substantial retaining forces because during use the inner shaft is protected by the outer shaft against mechanical stresses.  
         [0009]     Illustratively, the inner shaft may be of constant cross-sectional shape and smooth as far as its proximal end by which it may be inserted into a resectoscope main body borehole where it might be permanently soldered or welded into place. The inner shaft also may be connected by means of a thread or a bayonet lock to the borehole, or it may be merely plugged into the borehole and remain therein in a frictional or press-fit manner. Such a design is radially compact and consequently the enclosing outer connector also may be made compact and the entire assembly slender.  
         [0010]     Thereby, the inner shaft is affixed not to the resectoscope main body but to the outer shaft, namely to this outer shaft&#39;s proximal end zone. Illustratively, the inner shaft may be inserted by its widened proximal end zone into the proximal end zone of the outer shaft and soldered to it.  
         [0011]     The inner shaft also may be detachably affixed to the outer shaft, similarly to the way it may be detachably fastened to a borehole in the resectoscope main body.  
         [0012]     Thereby, the inner shaft is fitted with a connector element that, upon closure of the outer connector element, shall engage between the outer shaft and the resectoscope main body and in this way can be clamped into place when the outer connector element is closed. This feature offers a simple design variant where, however, the inner shaft can be removed only in the proximal direction from the outer shaft after the outer shaft has been detached from the main body—whereas, in other designs, the inner shaft may be removed in the distal direction from the outer shaft after loosening the inner connector element.  
         [0013]     Independently of the design of the invention of the inner shaft affixation, the outer connector element may be conventionally rotatable. Even regarding the configuration of the feed and drain ducts at the outward hookup stubs, known designs may be used, including a rotatable outer connector element.  
         [0014]     The invention is shown illustratively and schematically in the appended drawings. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]      FIG. 1  is a section of a first embodiment of a resectoscope of the invention, and  
         [0016]      FIGS. 2-4  show three further embodiments of details of  FIG. 1 . 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]     The resectoscope  1  shown in  FIG. 1  comprises a main body  2  to which an optics guide tube  4  is affixed inside a borehole  3 , the tube  4  passing proximally a distance from the main body  2  through an optics guide plate  5  within which it is affixed.  
         [0018]     A carriage  6  with a thumb ring  7  runs on the optics guide tube  4  and is connected by means of a leaf spring  8  with the optics guide tube  5 . As shown by  FIG. 1 , an optics  9  having an objective  10  can be inserted by means of the optics guide tube  4  in the distal direction, far beyond the main body  2 .  
         [0019]     By holding the implement in one hand, the surgeon may actuate finger grips  11  at the main body  2  to displace the carriage  6  in the axial direction of the resectoscope  1  to move an elongated support  12  affixed to the carriage  6 , indicated at  13 , through a duct  14  in the main body  2  far distally beyond the main body in order to reciprocate a surgical instrument (omitted in  FIG. 1 ), for instance an hf-loaded cutting loop, which is mounted at the end of the support  12 .  
         [0020]     An inner shaft  15  enclosing the optics  9  and the support  12  is affixed to the main body  2 . An outer shaft  16  enclosing the inner shaft  15  also is affixed to the main body  2 . The shafts  15 ,  16  illustratively are cross-sectionally circular and configured mutually coaxially.  
         [0021]     The tubular outer shaft  16  is affixed at its proximal end to an outer connector element  17  which, as shown, encloses the main body  2  and is detachably affixed by a locking pin  18  or some other means to the main body. The main body  2  supporting the outer connector element  17  comprises a borehole  19  within the outer surface  28  of the main body, the borehole  19  receiving the proximal terminal zone of the inner shaft  15 . The inner shaft  15  is fitted in its proximal terminal zone and at one site of its circumference with a resilient lip  20  engaging in a securing manner a matching radial clearance in the borehole  19 , as a result of which once inserted into the borehole  19 , the inner shaft  15  is elastically secured, though, the inner shaft  15  can be retracted again when the spring force is overcome.  
         [0022]     The gap between the shafts  15 ,  16  may communicate with the outside through a radially configured borehole  21  passing through the outer connector element  17  and the outer shaft  16  firmly affixed to it. The inside space of the inner shaft  15  may communicate with the outside through a borehole  22  passing through the inner shaft  15 , the main body  2  and the outer connector element  17 .  
         [0023]     In this embodiment, a hookup ring  23  rests rotatably on the outer surface of the outer connection element  17  and is fitted with circumferential ducts  24  and  25  in the axial position of the boreholes  21  and  22 , the ducts each communicating through valve-controlled hookup stubs  26 ,  27  to the outside in order to be connected as needed to evacuation or rinsing hoses.  
         [0024]     In the illustrated embodiment, the outer shaft  16 , jointly with the outer connector element  17 , may be removed from the main body  2  following withdrawal of the locking pin  18 . In the process the inner shaft  15  may remain at the main body  2  and then be pulled out of the borehole  19 . This design furthermore allows seizing only the inner shaft  15  at the distal end and to remove it first through the outer shaft  16  that is still in place.  
         [0025]      FIGS. 2 through 4  show three alternative embodiments as a segment of the central region of  FIG. 1 . As far as feasible these  FIGS. 2-4  retain the design details of  FIG. 1  and also their references.  
         [0026]      FIG. 2  shows an embodiment wherein the inner shaft  15  is a smooth tube—in particular devoid of the elastic lip  20 —inserted into the borehole  19  of the main body  2 . The inner shaft  15  may be affixed inside the borehole  19  for instance by soldering. In this embodiment, the inner shaft  15  therefore is rigidly affixed to the main body  2  whereas the outer shaft  16  is detachable as in  FIG. 1  on account of the outer connector element  17 .  
         [0027]     However, the outer shaft  15  may also be detachably connected to the main body  2  in the manner shown in  FIG. 2 . Illustratively, the inner shaft  15  and the borehole  19  may be threaded, as a result of which the inner shaft  15  can be screwed into the main body  2 .  
         [0028]     Moreover, the borehole  19  may be eliminated. In that case, the inner shaft  15  may be affixed in another way to the distal end face of the main body  2  which, then however must, at a minimum, allow the optics  9  and the support  12  to move into the inner shaft  15 .  
         [0029]      FIG. 3  shows another embodiment wherein the outer shaft  16  is affixed to the outer connector element  17  exactly as in the embodiment of  FIG. 1  and can be connected by the element  17  to the main body  2  which is omitted from  FIG. 3 . In this embodiment of  FIG. 3 , the inner shaft  15  is widened in its terminal zone  15 ′ to be the size of the inside diameter of the outer shaft  16  or of the outer connector element  17 , and is inserted into the outer shaft  16  and/or connector element  17 , as shown in  FIG. 3 . The inner shaft  15  may be clamped in position in this configuration, or illustratively it may be rigidly joined for instance by soldering to the outer shaft  16  respectively the main body  17 .  
         [0030]     The design of  FIG. 3  also allows connection of the inner shaft  15  in a detachable manner. Illustratively, it may be fitted in its widened distal terminal zone  15 ′ with an elastic lip  20  as shown in  FIG. 1 , the lip elastically engaging a corresponding clearance in the outer connector element  17 . Bayonet and screw connections also are applicable at this site.  
         [0031]     Another embodiment is shown in  FIG. 4 . The inner shaft  15  again is widened in its proximal terminal zone  15 ′ but—unlike the embodiment of  FIG. 3 —it comprises at its proximal end an outer flange  15 ″ which engages between the outer connector element  17  and the main body  2  when these are affixed to each other and which, once the outer connector element  17  has been locked, this flange  15 ″ shall be fixed in place. After the connection is dissolved and the outer connector element  17  is removed from the main body  2 , the inner shaft  15  may be pulled out of the outer shaft  16  in the proximal direction.  
         [0032]     The outer connector element  17  also may be designed in a manner other than shown in  FIGS. 1 through 4 , for instance, the rotatable hookup stub  23  may be omitted and the hookup stubs  26 ,  27  may be applied directly against the boreholes  21 ,  22 . Moreover, the outer connector element  17  may be supported in a rotatable manner on the main body  2 . In that case, and keeping the locking pin  18 , this pin might run in an outer groove of the main body  2 . In this embodiment, the annular ducts  24 ,  25  might run through the boreholes  21 ,  22  on the inside of the outer connector element  17 .  
         [0033]     If, in the above embodiment, the inner shaft  15  is permanently affixed to the main body, assembly will require inserting the implement support  12  from the distal side—contrary to conventional assembly.