Patent Publication Number: US-2005131278-A1

Title: Endoscope

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to an endoscope such as a urethroscope, which is used for working in the urinary bladder.  
      2. Description of the Prior Art  
      Endoscopes of the type referred to above have a long outer shaft with a substantially round cross section. An inner shaft may be disposed within the outer shaft, the cross section of which comprises a rounded portion and a straight portion, which merge into one another via two corners. A flexible working instrument can be introduced between the outer shaft and the straight section of the inner shaft, the distal end of which projects, in the introduced state, out of the distal end of the outer shaft. The working instrument can be operated via an actuating device arranged on the proximal end of the outer shaft. Endoscopes of the type referred to above additionally have an optical system, which may be inserted into the inner shaft.  
      During urethroscopy, the endoscope is introduced into the urethra and pushed from there further into the urinary bladder. The doctor can then view the region to be examined with the aid of the optical system and, if required, undertake, for instance, medical intervention or remove a tissue sample by means of the working instrument. In endoscopes which are not of the type referred to above, the distal end of the working instrument extends straight from the outer shaft. This means that the doctor can only reach with the working instrument regions in the urinary bladder which are situated in straight alignment with respect to the outlet into the urethra. Regions in the urinary bladder, which are situated laterally of the outlet to the urethra, can, however, not be reached with an endoscope which is not of the type referred to above.  
      As a result of this, endoscopes of the type referred to above have, at the distal end of the flattened region of the inner shaft, a pivotable deflecting lever, which is also named an “Albarran lever”. The working doctor can laterally deflect the flexible working instrument projecting out of the outer shaft by means of the deflecting lever, whereby the possibility is created of also reaching lateral regions in the urinary bladder with the working instrument.  
      Pivoting of the deflecting lever is effected by means of at least one actuating rod, which is coupled to the actuating device disposed at the proximal end of the endoscope. The pivoting of the deflecting lever is effected by movement of the actuating rod in the pulling and pushing direction, which is produced by means of the actuating device. The actuating rod is a long, bar-shaped component, the rod cross section being very small in relation to the length of the rod as a result of the shortage of space in the outer shaft of the endoscope. This has the consequence that the actuating rod can deflect laterally under excessive pushing forces. As a result of this deflection, it can occur that there is inadequate force transmission to pivot the deflecting lever.  
      In order to prevent lateral deflection of the actuating rod, a guide device is provided in endoscopes of the type referred to above, in which the actuating rod is guided. It is known to use a tube as the guide device, the cross section of which is only insubstantially larger than the cross section of the actuating rod. Furthermore, the guide device is so constructed and arranged that the guide device surrounds the actuating rod from its distal end to its proximal end in order to prevent lateral deflection of it when transmitting thrust.  
      There is, however, the major disadvantage that fluids, such as blood and secretions etc., can accumulate during an examination in the very narrow space between the guide device and the actuating rod and it is very difficult to remove these liquids from it. Before the endoscope can be reused, thorough cleaning is, however, absolutely necessary.  
      DE 10009020 discloses an endoscope of the type referred to above, which mitigates this problem in that a plurality of guide sleeves are provided as the guide device, which are arranged behind one another in the axial direction on the outer surface of the inner shaft. The region to be cleaned is reduced in this manner but the problem of poor cleanability, however, basically remains since residues can also be located in the guide sleeves, which may be removed only with difficulty.  
      It is the object of the present invention to provide an endoscope which, on the one hand renders adequate guiding of the actuating rods possible and, on the other hand can be well cleaned.  
     SUMMARY OF THE INVENTION  
      It is provided in accordance with the invention that the actuating rod is disposed within the inner shaft, the guide device being constituted by one of the corners and the optical system.  
      The guide device in the accordance with the invention is so constructed, as in the prior art, that it advantageously surrounds the actuating rod from its distal end to its proximal end so that deflection of the actuating rod is prevented over its entire length, when transmitting thrust. The guide device in accordance with the invention is, however, advantageously with respect to the prior art, capable of being taken apart such that the guide device may be very well cleaned.  
      For this purpose, the optical system, which constitutes a portion of the guide device in accordance with the invention, need merely be retracted in a manner which is in any event conventional. After the optical system has been withdrawn, the remaining portion of the guide device, namely the corner of the inner shaft and the actuating rod, are freely accessible within the inner shaft and may be easily reached, for instance by means of a brush or by washing, whereby thorough cleaning of the guide device is rendered possible.  
      A further advantage of the present invention is that the constitution of the guide device by the inner shaft and the optical system results in no additional component needing to be provided to constitute the guide device but instead components which are already present are so constructed that they assume responsibility for this function. The assumption of this function additionally offers the advantage that space can be saved in the cross sectional area of the endoscope, which is already very limited.  
      In known endoscopes of the type referred to above, the working instrument can catch on the actuating rods or the guide devices or guide sleeves during the introduction of the working instrument, whereby the introduction of the working instrument is frequently rendered difficult.  
      The present invention offers the advantage by comparison that the actuating rod and the guide device are concealed, that is to say guided within the inner shaft, so that catching on the working instrument is excluded from the outset. As a result of the transposition in accordance with the invention of the actuating rod from the outer cross sectional region, in which the working instrument is disposed, into the interior of the inner shaft, more space is also produced in the outer cross sectional region, whose construction is thus free for other purposes.  
      As already explained above, the distal end of the flexible working instrument can be laterally deflecting by means of the deflecting lever in order that the doctor can advance the distal end of the working instrument in a free and unimpeded matter to laterally situated regions of the urinary bladder. In accordance with an advantageous embodiment of the invention, the straight section of the inner shaft can have an integral inclined region at its distal end, formed by expansion of the shaft by a mandrel, on which the deflecting lever may be arranged. The distal end region of the working instrument is deflected with the aid of the inclined region into a first position during the introduction process. The distal end of the working instrument can then be deflected, if required, into a second, more strongly inclined position by means of the deflecting lever. The provision of the inclined region acts as a preparation for the subsequent deflection of the working instrument into a second position so that the force application necessary for this purpose is thus reduced.  
      In known endoscopes of the type referred to above, the inclined region is constituted by an inclined web, which is arranged and welded in a recess provided for this purpose at the distal end of the inner shaft. Various working steps are necessary for this purpose which are correspondingly cost intensive. By comparison, the construction of the inclined region in accordance with the invention results in a substantially more economical construction.  
      The invention will be explained below with reference to  FIGS. 1 and 2  of the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a sectional view on the line  1 - 1  in  FIG. 2  of the distal end of an endoscope in accordance with the invention  
       FIG. 2  is a sectional view on the line  2 - 2  in  FIG. 1   
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       FIG. 1  is a sectional view of the distal end of an endoscope in accordance with the invention. The endoscope has an outer shaft  10 , in which an inner shaft  11  is disposed. Retractably arranged in turn within the inner shaft  11  is an optical system  12 , by means of which the doctor can view the region of the operation.  
      Introduced between the outer shaft  10  and the inner shaft  11  is a working instrument  13 , which comprises a flexible shaft  14  and a working tool  15 . At its distal end, the inner shaft  11  has an inclined region  16 , by means of which the distal end of the working instrument  13  is easily deflected, as shown, during introduction into the endoscope from the direction of the shaft.  
      Arranged on the inclined region  16  is a deflecting lever  17 . The deflecting lever  17  is pivotally connected at its proximal end to the inner shaft  11  by a pivotal shaft  18 . The deflecting lever  17  is additionally pivotally connected at its proximal end via a laterally projecting arm  20  to an actuating rod  19 , which is coupled to an actuating device (not shown) arranged at the proximal end of the endoscope.  
      In the introduction state, the deflecting lever  17  is aligned in the direction of the inner shaft  11 . In order to be able to deflect the distal end of the working instrument  13  into the angled position, as shown in  FIG. 1 , the actuating rod  19  is pushed forwardly by the actuating device, whereby the deflecting lever  17  is pivoted upwardly about the pivotal shaft  18  and the distal end of the working instrument  13  is thus laterally deflected, as shown.  
       FIG. 2  shows, in cross section, the outer shaft  10  of the endoscope, which has a substantially round cross section. The inner shaft  11  and the working instrument  13  are arranged within the outer shaft  10 .  
      The cross section of the inner shaft  11  is so shaped that it has a straight section  30  and a rounded section  31  and two corners  32 , the transition from the straight to the rounded section occurring via respective corners  32 .  
      The optical system  12  is disposed in the inner shaft. A respective actuating rod  19  is additionally disposed in each corner  32 . As is clear in  FIG. 2 , the cross section of the inner shaft is so shaped that, when the optical system  12  is inserted, the two actuating rods  19  are closely surrounded by the two inner corners  32  of the inner shaft  11  and the optical system and thus enable guiding of the actuating rods  19  in this manner.  
      The optical system  12  can be withdrawn for cleaning purposes. After the optical system  12  has been pulled out, the remaining guide device, which is constituted by the two inner corners  32  of the inner shaft  11 , and the two actuating rods  19  are freely accessible within the inner shaft  11 . Cleaning can now be effected, e.g. by washing.  
      In a further exemplary embodiment, the endoscope in accordance with the invention can have only one actuating rod. The cross section of the inner shaft can be shaped in accordance with the first exemplary embodiment.