Abstract:
A device for manipulating a stylet unit having a stylet movable within a stylet sleeve, for positioning an electrode cable in a body cavity, has first and second relatively movable parts, with an interface area wherein respective surfaces of the first and second parts are in contact with each other. A groove is disposed in one of these surfaces and receives the stylet unit, with the stylet being connected to one of the first and second parts, and the stylet sleeve being connected to the other of the first and second parts.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a device for manipulating a stylet unit, of the type having a stylet sleeve and a stylet located therein, for positioning an electrode cable in a body cavity. In particular, the invention is directed to a device of this type having first and second parts which are movable relative to each other, one of which receives and holds the proximal end of the stylet and the other of which receives and holds the proximal end of the stylet sleeve, and a support and guide structure for a proximal section of the stylet which projects beyond the end of the stylet sleeve when the stylet and stylet sleeve are moved relative to each other. 
     2. Description of the Prior Art 
     A device for operating a stylet unit of the above kind for achieving a desired stiffening of an electrode cable during its advancement into a body cavity, e.g. via a vein into the atrium of the heart, and a desired final position for the distal end of the electrode cable by providing the cable with a bent L- or J-like shape is disclosed in U.S. Pat. No. 5,170,787. Here, the distal end of the stylet is pre-bent and is kept retracted inside the stylet sleeve during the electrode cable&#39;s insertion phase, giving the distal end of the electrode cable an essentially straight shape, the stylet, in the final positioning of the distal end of the electrode cable, being exposed outside its tubular sleeve to cause the distal end of the electrode cable to assume the desired curved shape. In order to achieve the exposure of the pre-bent distal end of the stylet outside its tubular sleeve, U.S. Pat. No. 5,170,787 proposes a device which either moves the stylet distally in relation to a stationary sleeve or moves the tubular sleeve proximally in relation to a stationary stylet. In principle, the latter option is preferable, since it does not entail any movement of the electrode cable in relation to the stylet unit&#39;s operating device. The known operating device comprises two stiff tubes, one telescoping inside the other, in order to obtain a stiffening that prevents the stylet from buckling when its free proximal end is slid distally inside the tubular sleeve respectively when the tubular sleeve is slid proximally over the free proximal end of the stylet in the operating device. This means that the operating device&#39;s total linear elongation is relatively large, since the total length of the telescoping tubes must be twice the length of the stylet&#39;s stroke in relation to the tubular sleeve. 
     An operating device for a stylet unit of the initially cited kind is disclosed in European Application 773 036 in which the stiff, telescoping tubes of the operating device according to U.S. Pat. No. 5,170,787 are replaced by a compressible helical spring which supports the free, proximal end of the stylet and which, in turn, is guided with a tight fit in an elongate cavity in a handle housing. In this way the total length of the operating device can be shortened considerably while the number of device parts could be reduced, resulting in lower manufacturing costs for the operating device. 
     SUMMARY OF THE INVENTION 
     An object of the present invention is to provide an operating device of the initially mentioned kind which can be even shorter, have even fewer parts and, accordingly, be made cheaper than previously proposed devices while retaining the requisite strength and reliability. 
     The above object is achieved in a device for manipulating a stylet unit of the type initially described wherein the device includes an arrangement for supporting and guiding the proximal section of the stylet which projects beyond the end of the stylet sleeve, when the stylet and the stylet sleeve are moved relative to each other, formed by a groove located in one of the relatively movable parts, this groove enclosing the stylet and being disposed in the surface of one of the relatively movable parts at an interface area of that surface which is in contact with the other relatively movable part. Therefore, in the inventive device the stiff, telescoping control tubes or the stylet guiding spring in previously proposed operating devices are not needed and are replaced by a simple stylet groove at the interface between both main parts of the operating device. 
     The shortest total length for the operating device is achieved when one of its parts is devised as a rotatingly supported roller body in a handle section in which the stylet and stylet sleeve are able to traverse a non-linear path when the stylet and stylet sleeve are moved in relation to one another when the configuration of the distal end of the electrode cable is to be changed. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic perspective view of an operating device with linear operation according to a first embodiment of the present invention. 
     FIG. 2 is an end view of the operating device of FIG.  1 . 
     FIG. 3 is a fragmentary, longitudinal sectional view of the operating device of FIG. 1 in the region of the attachment of the stylet to the handle section. 
     FIG. 4 is a schematic, exploded perspective view of a second embodiment of an operating device in accordance with the invention, with non-linear operation. 
     FIG. 5 is a schematic side view of a first practical embodiment of the operating device according to the invention, with non-linear operation. 
     FIG. 6 is a schematic side view of a second practical embodiment of the operating device according to the invention, with non-linear operation. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Preferred embodiments 
     FIG. 1 shows a schematic view of an embodiment, generally designated  10 , of a device according to the invention for manipulating a stylet unit  12  during the introduction and implantation of an electrode cable (not shown) in a body cavity, such as through a vein into the right atrium of the heart, for the purpose of achieving the desired stiffening of the electrode cable during its introduction and achieving the desired positioning and configuration, e.g. a J shape, for the distal end of the electrode cable. The operating device  10  according to the invention is therefore intended for manipulating a stylet unit  12  of the kind comprising an internal stylet  14  enclosed in a tubular sleeve  16 , both the sleeve  16  and the stylet  14  being intended for insertion into the central channel of the electrode cable for stiffening the cable during its introduction and for bending the distal end thereof into the desired shape. For this purpose, the distal end section of the internal stylet  12  is pre-bent in the known manner but enclosed inside the tubular sleeve  16  during the electrode cable&#39;s advancement in order to keep the distal end of the stylet unit  12  and, accordingly, the electrode cable essentially straight. When the distal end of the electrode cable has been maneuvered into e.g. the right atrium of the heart, the tubular stylet sleeve  16  can be retracted, whereupon the pre-tensioning of the exposed, pre-bent distal end section of the stylet  14  inside the electrode cable causes the distal end section of the electrode cable to bend into the desired shape, e.g. an L shape or a J shape. Alternately, the stylet can be moved out from the stylet sleeve, but this would result in simultaneous retraction of the electrode cable from the operating device. The operating device  10  according to the invention is therefore designed to guide this movement of the stylet sleeve  16  in relation to the stylet  14 . 
     The embodiment of the operating device  10 , shown in FIGS. 1-3, according to the invention is of a type with linear operation and comprises, in principle, a first part, for instance a housing  18  devised as a handle, and a second part, devised as a slide, which is supported so as to be linearly movable into and out from the housing  18 . The slide  20  has an upper surface  22  which slides with a tight fit against the opposing surface  24  of a cavity in the housing  18 . A groove  26 , in which a proximal end section  28  of the stylet sleeve  16  is attached, is made on the upper surface  22  of the slide  20 . A proximal end section  30  of the stylet  14 , which projects from this end section  28 , extends to the rear in the groove  26  to an attachment point at which the end of the stylet  32  is bent up and fastened in a perpendicular blind hole  34  opening onto the groove  26  in the housing  8 , as best shown in FIG.  3 . The groove  26  and the opposite surface  24  accordingly form a guide channel which encloses the stylet  14  with a relatively tight fit, preventing it from buckling when the slide  20  and stylet sleeve  16  slidingly are withdrawn to the rear. The slide  20  has a grip section  36 , which extends through a slot  38  into the lower part of the housing  18  to facilitate linear movement of the slide  20  in relation to the housing  18 . 
     The operating device according to the embodiment in FIGS. 1-3 operates as follows: 
     Before the electrode cable is introduced into the body cavity, the stylet unit  12  is fully inserted into the electrode cable with the stylet  14  enclosed by the stylet sleeve  16 , i.e. the operating slide  20  is held in a forward, distal end position in the housing  18 . When the tubular sleeve&#39;s  16  distal end reaches the distal end of the electrode cable, the latter can be inserted into the body cavity, e.g. the right atrium of the heart. When the cable reaches the atrium, the distal end section of the electrode cable is bent into the desired L shape or J shape by retracting the slide  20 , i.e. in a proximal direction, with the fingers, the tubular sleeve  14  accompanying the slide  20  and exposing the pre-bent distal end of the stylet  14  at the distal end of the electrode cable, thus bending the cable into the desired shape depending on how much of the bent, distal end of the stylet is exposed. Here, the primary task of the groove  26  is to enclose or stiffen the proximal, free end section  30  of the stylet  14  with a relatively tight fit, thereby preventing buckling thereof due to friction between the stylet  14  and the sleeve  16  when the latter is retracted along the stylet  14 . 
     After the distal end of the electrode cable reaches its final position, it can be actively affixed to the heart wall by manual rotation of a rotation sleeve (not shown), on the proximal end of the slide  20 , to which the electrode cable&#39;s proximal contact pin is attached. 
     Within the scope of the present invention, the relative movement of the housing  8  and slide  20  can alternately be reversed in the embodiment according to FIGS. 1-3, i.e. the proximal end of the stylet  14  can be attached to the slide  20 , the stylet housing  16  attached to the housing  18  and the groove  26  devised in the housing, the stylet  14  being insertable into and out of a stationary sleeve  16 . However, this means that the distance between the distal end of the electrode cable and the operating device  10  would increase when there is distal displacement of the stylet  14 , and the proximal end of the electrode cable therefore must be free to follow this movement. 
     FIG. 4 shows a view of an alternative embodiment of the operating device according to the invention, which operates with non-linear relative movement between the stylet and the stylet sleeve. Thus, this embodiment employs a housing  18 ′ in which a roller body  20 ′ is rotatably arranged in a cavity  40  in the housing. The roller body  20 ′ has a peripheral guide groove  26 ′ for the stylet  14 , and the housing  18 ′ has a through hole  42  for the proximal end section of the stylet sleeve  16  which is to be fastened to the guide groove  26 ′, The housing  18 ′ further has an attachment point  34 ′, located opposite the stylet groove  26 ′, for the proximal end of the stylet  32 . Thus, by rotating the roller body  29 ′ relative to the housing  18 ′, the stylet sleeve  16  can be moved towards the attachment point  34 ′, thereby sliding over the stylet  14 , guided so as to prevent stylet buckling in the stylet groove  26 ′, the pre-bent distal end section of the stylet  14  being moved out from the stylet sleeve  16  to the degree required to shape the distal end section of the electrode cable into a suitable J shape. Since non-linear relative motion is achieved between the stylet  14  and the sleeve  16 , in this instance, the operating device  16  can be devised with a shorter length. 
     FIGS. 5 and 6 schematically depict two practical embodiments of a control device according to FIG.  4 . 
     In FIG. 5, the housing  18 ′ has been devised as a handle, so rotation of the roller body  20 ′ can be performed with one finger. 
     In the embodiment according to FIG. 6, the roller body  20 ″ can be rotated in relation to the handle  18 ″ with a lever  44  in the middle of same, so the stylet unit can be manipulated by manually pressing the lever  44  and handle  18 ″ towards each other. Here, the lever  44  is preferably pre-tensioned with a spring (not shown) which presses the lever  44  towards an end position away from the housing  18 ″. 
     In the embodiments according to FIGS. 4-6, the relative movement of the stylet and the stylet sleeve also can be reversed, i.e. the stylet&#39;s and sleeve&#39;s attachment points and the groove&#39;s location in the housing and roller body respectively can change place. 
     Although modifications and changes may be suggested by those skilled in the art, it is the intention of the inventor to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of his contribution to the art.