Abstract:
A medical instrument for dilating osseous structures, with a shaft on whose distal end a tool point is positioned and on whose proximal end a handle is positioned, such that the handle and the tool point are in active connection with one another by means of an actuating element in such a way that by actuating the handle the tool point can spread radially at least partially and where the distal end of the actuating element has a thickened configuration. To provide a dilating instrument that is sufficiently stable and allows for sensitive actuation, it is proposed with the invention that the tool point should consist of several segments that can radiate radially outward and enclose the thickened distal end of the actuating element essentially completely, when the tool point is in the closed position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims priority of German patent application No. 10 2009 018 723.5 filed on Apr. 27, 2009, the content of which is incorporated herein by reference. 
       FIELD OF THE INVENTION 
       [0002]    The invention relates to a medical instrument for dilating osseous structures, with a shaft on whose distal end a tool point is positioned and on whose proximal end a handle is positioned, such that the handle and tool point are in active connection with one another by means of an actuating element in such a way that, by actuating the handle, the tool point can be radially widened at least partially and such that the distal end of the actuating element has a thickened form. 
       BACKGROUND OF THE INVENTION 
       [0003]    According to the invention, dilating instruments are used, for instance, in endoscopic ENT surgery for widening a patient&#39;s frontal sinus and removing osseous growths in the frontal sinus. 
         [0004]    A generic medical dilating instrument is disclosed, for instance, in WO 2008/134288 A2. In a first embodiment of this known dilating instrument, the tool point consists of several lamellae, which are bound together distally and are compressed together by means of the actuating element in such a way that the lamellae widen radially in a balloon-like manner. This construction is especially suited for spreading soft tissue, but the lamellae buckle inward when they are used for removing osseous growths. 
         [0005]    According to a second embodiment of this known dilating instrument, the tool point consists of several lamellae that are not bound together on the distal end and can be bent open radially by means of a thickening on the distal end of the actuating element. The disadvantage of this embodiment is that the tool point is open even when the lamellae of the tool point are in the non-spread position, so that tissue can penetrate into the dilating mechanism. In addition, the elastically bendable lamellae allow the user only a limited tactile control in the functioning of the tool point. 
         [0006]    In addition, instruments for dilating heart vessels are known that can widen vessels and penetrate through vessel closures. These known medical instruments for widening vessels, however, are only suited for transmitting minor forces, in order to prevent injury to the vessels that are to be widened. These known instruments, however, are not suited for dilating osseous growths such as in the frontal sinus. 
         [0007]    On this basis it is the object of the invention to provide a dilating instrument that is of sufficient stability and also allows sensitive actuation. 
       SUMMARY OF THE INVENTION 
       [0008]    The solution to this object, according to the invention, is characterized in that the tool point consists of several segments that can pivot radially outward and that enclose the thickened distal end of the actuating element essentially completely when the tool point is in the closed position. 
         [0009]    As a result of this configuration of the tool point with the pivotable segments that completely enclose the distal end of the actuating element, the inventive tool point, when the segments are in closed position, is completely closed with respect to the outside, so that the dilating mechanism is also protected. In addition, the pivotable segments can be configured as form-stable pivoting elements that allow both great widening strength and sensitive actuation by the operator. 
         [0010]    In advantageous manner, the pivotable segments of the tool point completely enclose the thickened distal end of the actuating element when the tool point is in closed position; but because of manufacturing standards and tolerances, minimal gaps can also remain between the pivotable segments although they pose no threat to the inventive essentially complete enclosing of the thickened distal end of the actuation element. 
         [0011]    According to a preferred embodiment of the invention, it is proposed for configuring the dilation mechanism that an insertion space should be configured for the thickened distal end of the actuation element in the interior of the tool point configured by the individual segments, so that the inner contour of the individual segments of the tool point is configured in such a way that, in a displacement of the thickened distal end of the actuating element, the segments pivot radially outward. As a result of the displacement of the actuating element, advantageously configured as a push-pull rod, in the axial direction of the shaft, the pivotable segments of the tool point are pressed radially outward. 
         [0012]    The insertion space for the thickened distal end of the actuating element is advantageously configured so that it narrows conically toward the proximal end of the segments, so that when the actuating element is withdrawn in the proximal direction, the segments are automatically pivoted outward and open the distal end of the tool point in the form of a tulip blossom. 
         [0013]    The thickened distal end of the actuation element, according to a practical embodiment of the invention, is spherical or conical in configuration. 
         [0014]    According to a first inventive embodiment, it is proposed that the tool point should consist of four pivotable segments, each of which is jointed at a 90-degree angle to the others on the proximal end of the tool point. 
         [0015]    To facilitate non-traumatic insertion of the tool point into the surgical area, it is proposed with the invention that the outer contour of the distal end of the segments of the tool point should be configured to taper conically when the tool point is in closed position. In addition to the conical configuration of only the distal end of the tool point, with an alternative embodiment it is proposed that the entire outer contour of the segments of the tool point should be configured to taper conically toward the distal end in several stages when the tool point is in closed position. 
         [0016]    In addition, with a practical embodiment of the invention it is proposed that the outer sides of the segments of the tool point, with the tool point in opened position, should be configured to run essentially parallel to one another. This parallel configuration of the sides of the pivotable segments when the tool point is in the opened working position is advantageous in order to prevent any slippage outward of the tool point into areas of the surgical area that are not yet examined. 
         [0017]    Because the tool point, especially in removing osseous growths, is exposed to steady abrasion, it is proposed with the invention that the tool point should be removably connected with the shaft. 
         [0018]    The assembly and disassembly of the instrument, according to the invention, can be facilitated if the portion of the actuating element positioned in the tool point is coupled removably with the portion of the actuating element positioned in the shaft by means of a coupling mechanism. 
         [0019]    It is finally proposed with the invention that the tool point should be coverable with an elastic casing of synthetic material in order to prevent penetration of tissue into the dilating mechanism. 
         [0020]    It is further proposed with the invention that the pivotable segments of the tool point should be movable from the opened position of the tool point back into the closed point of the tool point by means of the elastic synthetic casing. In this embodiment the return force of the elastic synthetic casing is used in order to move the tool point back into the closed position after the widening of the pivotable segments and the related stretching of the synthetic casing. 
         [0021]    To configure the elastic synthetic casing, it is proposed with the invention that the elastic synthetic casing should take the form of a covering that is open at the proximal end and has a surrounding insulating element configured on its proximal edge. 
         [0022]    The insulating element should advantageously be configured as a surrounding thickening, which can be affixed in a corresponding surround groove of the tool point. 
         [0023]    Additional properties and advantages of the invention can be seen from the appended illustrations, in which five embodiments of an inventive medical dilating instrument are presented only in exemplary manner, without restricting the invention to these examples. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  shows a schematic, partly cut-out side view of an inventive medical dilating instrument. 
           [0025]      FIG. 2  shows an enlarged depiction of detail II, showing a first embodiment of a tool point in the closed position. 
           [0026]      FIG. 3  shows a non-cut-out perspective view of the depiction in  FIG. 2 , but showing the tool point in opened position. 
           [0027]      FIG. 4  shows a cut-out side view of a second embodiment of a tool point in closed position. 
           [0028]      FIG. 5  shows a side view of the tool point according to  FIG. 4 , but showing the opened position. 
           [0029]      FIG. 6  shows a side view of a third embodiment of a tool point in closed position. 
           [0030]      FIG. 7  shows a side view of a fourth embodiment of a tool point in closed position. 
           [0031]      FIG. 8  shows a cut-out side view of a fifth embodiment of a tool point in closed position. 
           [0032]      FIG. 9  shows a side view of the tool point according to  FIG. 8 , but showing the opened position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0033]    The medical dilating instrument  1  shown schematically in  FIG. 1  consists essentially of a hollow shaft  2  on whose proximal end a handle  3  is positioned that in the illustrated embodiment consists of a rigid gripping member  3   a  and a gripping member  3   b  that can pivot with respect to the rigid gripping member  3   a . Positioned on the distal end of the shaft  2  is a tool point  4 , which, as can be seen in particular from  FIG. 3 , consists of several segments  5 , which are mounted on the proximal end of the tool point  4  so that they can pivot radially outward around the pivot axis  6 . 
         [0034]    As can further be seen from  FIG. 1 , the tool point  4  and the pivotable gripping member  3   b  of the handle  3  are in active connection with one another by means of an actuating element  7  that is mounted so that it can slide axially within the hollow shaft  2  and is configured as a pull rod, in such a way that moving the gripping member  3   b  of the handle  3  causes the pivoting of the segments  5  of the tool point  4  from the closed position (hatch-marked depiction in  FIG. 1  as well as in  FIGS. 2 ,  4 ,  6 , and  7 ) into closed position (dotted depiction in  FIG. 1  as well as  FIGS. 3 and 5 ) or vice versa. The resulting position of the pivotable gripping member  3   b  of the handle  3  in each case in  FIG. 1  is likewise illustrated as hatch-marked (for the closed position) and dotted (for the opened position). 
         [0035]    Alternatively to the illustrated configuration of the actuating element  7  as a pull rod, it is also possible of course to configure the mechanism of the dilating instrument  1  in such a way that the actuating element  7  can take the form of a push rod. 
         [0036]    In the illustrated embodiments, the tool point  4  consists in each case of four segments  5 , which are positioned at 90-degree angles to one another so that they can pivot on the proximal end of the tool point  4 . It is also possible of course to construct the tool point  4  to consist of more or fewer segments  5 , for instance as having three segments  5 , which are positioned at 120-degree angles to one another so that they can pivot on the proximal end of the tool point  4 . 
         [0037]    The pivotable segments  5  of the tool point  4  are always positioned and configured in such a way that, when the tool point  4  is in closed position, they form a closed outer contour and, as can be seen from  FIG. 2 , they essentially completely enclose the distal end  8  of the actuating element  7 . 
         [0038]    The term “essentially completely enclose” is to be understood to mean that, because of manufacturing standards and tolerances, minimal gaps can also remain between the pivotable segments although they pose no threat to the required enclosing of the thickened distal end of the actuating element. However, with the tool point in closed position, the pivotable segments of the tool point advantageously enclose the thickened distal end of the actuating element, completely and free of gaps. 
         [0039]    To allow the dilating instrument  1 , with the tool point  4  in front, to penetrate non-traumatically into the surgical area, for instance into a front sinus, the outer contour of the distal end of the segments  5  of the tool point  4  is also configured in all embodiments, with the tool point  4  in closed position, as tapering conically. 
         [0040]    The embodiments illustrated in  FIGS. 1 through 7  are distinguished from one another by the configuration of the outer contour of the tool point  4 , which presents them with the segments in the closed and/or opened position. 
         [0041]    In the first embodiment, shown in  FIGS. 1 through 3 , the tool point  4  has a double-conical configuration in such a way that it widens at first in the direction going from the pivot axis  6  in the distal direction and then, in turn, tapers conically toward the distal end of the tool point  4 . 
         [0042]    The second embodiment for configuring the tool point  4 , seen in  FIGS. 4 and 6 , is distinguished from the previously described embodiment primarily in that the outer sides of the segments  5  of the tool point  4 , with the tool point  4  in opened working position, are configured to run essentially parallel to one another. 
         [0043]    This parallel configuration of the sides of the pivotable segments  5  in opened working position is advantageous in order to ensure the ability to prevent the tool point  4  from slipping away into portions of the surgical area not yet examined, when the tool point  4  of the dilating instrument  1  is moved back and forth by the operator to widen the surgical area and break up osseous growths. 
         [0044]    In the third embodiment, shown in  FIG. 6 , the outer sides of the segments  5  of the tool point  4 , with the tool point  4  in closed position, are configured to run essentially parallel to one another and only point toward one another while tapering conically at the distal end of the tool point  4 . 
         [0045]      FIG. 7 , finally, shows a fourth embodiment for configuring the outer contour of the tool point  4 , in which the outer contour of the segments  5  of the tool point  4 , with the tool point in closed position, is configured as tapering conically in several stages toward the distal end. 
         [0046]    Because the tool point  4  or the pivotable segments  5  of the tool point  4  are subject to a certain abrasion from use, the illustrated embodiments of the dilating instrument  2  are configured in such a way that the tool point  4  can be removably affixed to the shaft  2  by means of a coupling mechanism  10 . 
         [0047]    Likewise, in the embodiment shown in  FIG. 2 , the portion of the actuating element  7  mounted in the tool point  4  is removably coupled with the portion of the actuating element  7  mounted in the shaft  2  by means of a coupling mechanism  10 . It is also possible of course to produce the actuating element  7  as a single piece in such a way that it can be inserted from the distal end into the opened tool point  4  and the shaft  2 . 
         [0048]    The dilating instrument  1  described above is employed in endoscopic surgery in the following way: 
         [0049]    Starting with the tool point  4  in closed position as shown in  FIG. 1  (hatch-marked line) as well as  FIGS. 2 ,  4 ,  6 , and  7 , the dilating instrument  1  is inserted into the surgical area, in particular into a patient&#39;s sinus cavity, with the tool point  4  in front, in order then to widen constricted sections. 
         [0050]    To widen constricted sections of the surgical area, including for the removal of osseous growths, the operator shifts the pivotable member  3   b  of the handle into the position shown with dots in  FIG. 1 , so that the actuating element  7  coupled with this gripping member  3   b  is pulled in the proximal direction. On the distal end, pulling back the actuating element  7  in the proximal direction causes the segments  5  of the tool point  4  to be pivoted radially outward by means of the thickened distal end  8  of the actuating element  7  into the tool point&#39;s  4  opened working position as shown in  FIG. 1  (dotted line) as well as  FIGS. 3 and 5 . 
         [0051]    In contrast to the construction of the tool points from individual lamellae as known in the art, in the previously described structure of the tool point  4  the individual pivotable segments  5  that are to be opened by the thickened distal end  8  of the actuation element  7  can be configured as clearly more massive and thus more form-stable, so that the points of the segments  5  can also be employed for widening and breaking up growths. Thanks to this feature, the spreading surface of the tool point  4  as well as the diameter of the opened tool point  4  can be made larger. 
         [0052]    In addition, the mechanical spreading force in the described configuration of the tool point  4  is not dependent on the flexing strength of individual lamellae, but is instead based purely on the force transmission by means of the leverages applied. 
         [0053]    To prevent the penetration of tissue into the tulip-shaped opened tool point  4 , it is additionally possible to cover the tool point  4  with an elastic synthetic casing  11  as is shown in  FIGS. 8 and 9 . But even without such a covering, the described dilation mechanism can be applied without problem because the simple and stable structure ensures good and rapid cleaning of all components. 
         [0054]    As can be seen from  FIGS. 8 and 9 , the synthetic casing  11  is configured as a covering that is open on the proximal end and can be pulled starting from the distal side over the tool point  4 . On the proximal end the synthetic casing  11  has a surrounding insulating element  12 , which is contiguous with the tool point  4  and insulates it in order to prevent the penetration of tissue and/or fluid under the synthetic casing  11  and thus into the interior of the tool point  4 . In the illustrated embodiment the insulating element  12  takes the form of a surrounding bulge-like thickening, which can be affixed in a corresponding surrounding groove  13  of the tool point  4 . 
         [0055]    Affixing the synthetic casing  11  in the groove, in addition, has the advantage that it prevents the synthetic casing  11  from being pulled off by the tool point  4  upon withdrawing the dilating instrument  1  in the axial direction. 
         [0056]    In addition, even if the elastic synthetic casing  11  is graphically illustrated only in the fifth embodiment shown in  FIGS. 8 and 9 , synthetic casings  11  of this type can also be used in all other embodiments shown in  FIGS. 2 through 7  and previously described. 
         [0057]    In addition to the protection of the tool point  4  against impurities, the elastic synthetic casing  11  can be used for shifting the pivotable segments  5  of the tool point  4  from the tool&#39;s  4  opened position back into its closed position. In this configuration the return force of the elastic synthetic casing  11  is taken advantage of, after spreading the pivotable segments  5  and the related stretching of the synthetic casing  11 , to shift the tool point  4  back into the closed position as soon as the thickened distal end  8  of the actuating element  7  no longer presses the pivotable segments  5  of the tool point  4  into the opened position. 
         [0058]    A dilating instrument  1  configured as described above is distinguished in that the dilating mechanism is very resistant because of the mechanism that is powered entirely by lever and pivot points, and in addition it allows the operator a sensitive working because the force applied by the handle  3  arrives in the surgical area essentially free of any play.