Abstract:
The invention relates to a surgical retaining instrument for bone plates. The retaining instrument comprises a carrying element and two plate retaining jaws arranged on the carrying element. The mutual distance of the plate retaining jaws can be changed in order to pick up or release a bone plate. Furthermore, an actuating device is provided, which has two arms, which can be moved relative to each other and which are designed to change the mutual distance of the plate retaining jaws. The carrying element is rotatably mounted relative to the arms.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a national phase entry under 35 U.S.C. §371 of International Application No. PCT/EP2012/000130 filed Jan. 12, 2012, published in German, which claims priority from German Patent Application No. 10 2011 008 557.2 filed Jan. 14, 2011, all of which are incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present disclosure generally relates to the field of surgical instruments. More specifically, it describes an instrument for retaining bone plates. A retaining instrument for bone plates is known from the document DE 197 09 182 A1 (U.S. Pat. No. 5,755,721). This retaining instrument allows a surgeon to grasp a bone plate that is to be attached to a bone, and place it at the intended attachment position. 
         [0003]    The retaining instrument comprises two sleeves, disposed concentrically to one another, that can be moved in opposition. The inner sleeve has two diametrically opposing tongues that extend radially outward at an angle. The inner diameter of the outer sleeve is only slightly larger than the outer diameter of the inner sleeve in the region outside of the splayed tongues. The free end of each tongue is formed as a plate retaining jaw. 
         [0004]    Sliding the outer sleeve along the inner sleeve in the direction of the plate retaining jaws causes a relative movement of the two tongues towards one another and therefore of the plate retaining jaws as well. A bone plate disposed between the closing plate retaining jaws is thus clamped by the plate retaining jaws and can be transported to the desired attachment position on the bone using the retaining instrument. In order to release the bone plate after its attachment, the outer sleeve is moved back, away from the retaining jaws, which causes the tongues to spread apart and therefore the plate retaining jaws as well. 
         [0005]    The actuating mechanism for the plate retaining jaws described in the document DE 197 09 182 A1 is not without problems in any case. Thus the retaining instrument must be gripped with the first hand, while the second hand actuates the clamping mechanism, that is, displaces the outer sleeve. Handling the retaining instrument known from prior art therefore “occupies” both of the surgeon&#39;s hands. 
         [0006]    Moreover, it has been found that the sliding movement to release the bone plate occurs very close to the surgical site and therefore cannot always be achieved unhindered. In addition, the surgeon is not always able to reliably grip the outer sleeve and thereby release the bone plate in all surgical scenarios. 
       BRIEF SUMMARY OF THE INVENTION 
       [0007]    There is a need for a surgical retaining instrument for bone plates that comprises an alternative actuating mechanism. 
         [0008]    According to one aspect, a surgical retaining instrument for bone plates is suggested comprising a support member, two plate retaining jaws disposed on the support member, the mutual spacing between which can be modified to grasp or release a bone plate, and an actuating device having two relatively movable arms that can be moved towards one another, which are designed to modify the mutual spacing between the plate retaining jaws, wherein the support member is rotatably mounted with respect to the arms. 
         [0009]    The support member may be elastically deformable. In this case, the actuating device may be designed to elastically deform the support member in order to modify the mutual spacing between the plate retaining jaws. The resisting force accompanying the elastic deformation can be directed in such a way that the support member (and thereby the plate retaining jaws) is pushed into its initial position. In general, the initial position of the plate retaining jaws can be a release position or a receiving position when the actuating device is not actuated. 
         [0010]    The support member can have at least one through-hole. In such an embodiment of the support member, the plate retaining jaws may be disposed on opposing sides of the through-hole on the support member. 
         [0011]    For the rotatable mounting of the support member, this support member may have a mounting contour, the encasing end of which is circular. For example, the support member may have a circular mounting contour. The mounting contour may be provided on an outer periphery of the support member. 
         [0012]    The support member may be formed as a circular disc or as a ring at least in sections (thus having a through-hole). According to a variant, the support member is formed as a split ring. The split ring can be elastically deformable. 
         [0013]    In one implementation of the retaining instrument having a support member that has a through-hole, the retaining instrument may further have a cylindrical sleeve disposed so that it is concentric to the through-hole on the support member. The cylindrical sleeve can perform various tasks. Thus the sleeve can serve as a drill guide or may be designed to accommodate a drill guide. In one embodiment of the drill sleeve as a separate component, it may be removably attached to the cylindrical sleeve (for example with a force-fit, frictionally engaged or form-fit connection). 
         [0014]    The rotatability of the support member can be limited to an angular range of less than 360°. For this purpose, the mounting of the support member may be provided with corresponding stops. Alternatively, the support member can also be rotatable over an angular range of more than 360°. In other words, the support member can be designed so that it is freely rotatable. 
         [0015]    A mounting provided for the support member can include at least one arch-shaped groove. The groove may be formed in one arm or in both arms of the actuating device. Alternatively or in addition to this, a (possibly complementary) arch-shaped groove may also form the above mentioned mounting contour provided on the support member. 
         [0016]    The two arms of the actuating device may be linked to one another in an articulated manner. In general, the arms can be associated with an actuating device formed on the principle of scissors, forceps or tweezers. In the case of a scissors- or forceps-like realization, the joint is formed in a central section of the two arms, while in the case of a tweezer-like realization, the joint connects the two arms at their end section. 
         [0017]    The retaining instrument can be ergonomically shaped in various ways. For example, the retaining instrument may comprise angled arms. The arms may be angled approximately in the shape of a Z, for example. 
         [0018]    According to one embodiment, the retaining instrument further comprises a locking device in order to lock the mutual position of the arms. Locking the mutual position of the arms may be accompanied by locking or at least impeding the rotatability of the support member. Thus when a bone plate is being grasped, a rotation of the bone plate with respect to the arms of the actuating device can be prevented or at least limited. 
         [0019]    According to another aspect, a retaining instrument system is provided, which comprises the retaining instrument described here as well as a bone plate. In the case of the bone plate, it may be a linear plate. The linear plate may have either a curved or a straight form. According to one embodiment, the linear plate may be designed for attachment in the region of the jaw bone. 
         [0020]    A contouring of the plate retaining jaws (on the side facing the bone plate) may be selected to correspond to a contouring of the bone plate (on the side facing the retaining jaws). For example, the bone plate may be bulbously contoured (for example in the region of a through-hole for a bone screw). The retaining jaws can, accordingly, each have a bulbously contoured receiving structure for the bone plate. 
         [0021]    The system may further comprise a drill sleeve that is used as a guide for a drill and/or for the introduction of a bone screw for attaching the bone plate. In an embodiment in which both the support member and the bone plate each have a through-hole, the retaining instrument can allow the drill sleeve to be accommodated concentrically with regard to both through-holes. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]    Further details, advantages and aspects of the retaining instrument and retaining instrument system described herein arise from the following description of an embodiment taken in conjunction with the figures wherein: 
           [0023]      FIG. 1  is a perspective view of an embodiment of a scissors-shaped surgical retaining instrument in a release position; 
           [0024]      FIG. 2  is a side view of the retaining instrument according to  FIG. 1 ; 
           [0025]      FIG. 3  is a top view of the retaining instrument according to  FIG. 1  in a receiving position; 
           [0026]      FIG. 4  is a detail enlargement from  FIG. 3  in a joint area; 
           [0027]      FIG. 5  is a front view of the retaining instrument according to  FIG. 1 ; 
           [0028]      FIG. 6  is a detail enlargement from  FIG. 5  in the region of a locking device; 
           [0029]      FIG. 7  is a perspective view of the functional end of the retaining instrument according to  FIG. 1  in the release position; 
           [0030]      FIG. 8  is a top view of the functional end of the retaining instrument according to  FIG. 1  in a receiving position; 
           [0031]      FIG. 9  is a sectional view of the functional end along the IX-IX line according to  FIG. 8 ; 
           [0032]      FIG. 10  is a perspective view of a drill sleeve for use with the retaining instrument according to  FIG. 1 ; and 
           [0033]      FIG. 11  is a perspective view of an embodiment of a retaining instrument system with retaining instrument, drill sleeve and bone plate. 
       
    
    
     DETAILED DESCRIPTION 
       [0034]      FIG. 1  shows a perspective view of an embodiment of a scissors-shaped surgical retaining instrument  10 . The retaining instrument  10 , shown in a receiving position, comprises two arms  14 ,  16  that are connected to one another in an articulated manner in a central section  12 . Each of the two arms  14 ,  16  has a grip end as well as a functional end. 
         [0035]    A finger hole  18 ,  20  is formed at the grip end of each arm  14 ,  16  as on a pair of scissors. The arms  14 ,  16  each have a semi-circularly curved actuation segment  22 ,  24  on the functional ends opposite the finger holes  18 ,  22 . A locking device  28  is formed in the region of the two finger holes  18 ,  20 . The locking device  28  makes it possible to lock the mutual position of the two arms  14 ,  16 . The operation and structure of the locking device  28  is described in greater detail below with reference to  FIGS. 5 and 6 . 
         [0036]    One of these plate retaining mechanisms  26  that can be actuated is disposed between the two actuation segments  22 ,  24  in such a way that it is irremovable. The structure and the function of the plate retaining mechanism  26  is described in greater detail below with reference to  FIGS. 7 to 9 . 
         [0037]      FIG. 2  shows a side view of the surgical retaining instrument  10  according to  FIG. 2 . As illustrated in  FIG. 2 , the arms  14 ,  16  of the retaining instrument  10  are angled approximately in the shape of a Z. This angling of the arms  14 ,  16  makes it easier to handle the retaining instrument  10  in conjunction with the placement of a bone plate that has been grasped, onto a bone. 
         [0038]    Clearly recognizable in  FIG. 2  is the fact that the actuation segments  22 ,  24  each have a lateral slot  30  (only the slot  30  of the actuation segment  22  is visible in the side view according to  FIG. 2 ). The slots  30  allow the surgeon to visually check the position of the plate retaining mechanism  26 , for example. Moreover, the slots  30  facilitate the entry of a sterilizing medium into the plate retaining mechanism  26 . 
         [0039]      FIG. 3  shows a view of the plate retaining instrument in a receiving position. For the sake of clarity, the bone plate being grasped is not shown.  FIG. 3  clearly shows the fact that the locking device  28  is in the receiving position is in a locked state. 
         [0040]      FIG. 4  shows a detail enlargement of the retaining instrument  10  according to  FIG. 3  in the region of the central section  12  where the two arms  14 ,  16  are connected to one another in an articulated manner. As can be seen in  FIG. 4 , a bearing pin  32  is provided, which defines the pivot point of the two arms  14 ,  16  relative to each other. 
         [0041]      FIG. 5  shows a front view of the retaining instrument in a receiving position, in which the locking device  28  is locked.  FIG. 6  shows a detail enlargement from  FIG. 5  in the region of the locking device  28 . As shown in  FIGS. 5 and 6 , the locking device  28  comprises two tongue-shaped sections  32 ,  34 . 
         [0042]    A first tongue-shaped section  34  is coupled to the arm  14  in the region of the finger hole  18 , while a second tongue-shaped section  36  is coupled to the other arm  16  in the region of the other finger hole  20 . The two tongue-shaped sections  34 ,  36  are each provided with serrations  38 ,  40  on the sides facing one another. The two serrated sections  38 ,  40  engage in one another when the retaining instrument is moved from the release position shown in  FIG. 1  into the receiving position shown in  FIG. 3 , or in other words when the two arms  14 ,  16  are moved towards one another. Once the serrated sections  38 ,  40  have engaged with one another, the relative position of the two arms  14 ,  16  is locked. In order to release the lock, it is necessary to pivot the two arms  14 ,  16  in the region of the finger holes  18 ,  20  relative to one another. This pivoting motion occurs out of the plane of the drawing in the view according to  FIG. 3 . 
         [0043]    The following describes the structure and functioning of the plate retaining mechanism  26  with reference to  FIGS. 7 to 9 .  FIG. 7  shows a detail enlargement of the functional end of the retaining instrument  10  in the release position according to  FIG. 1 ,  FIG. 8  shows a detail enlargement of the functional end of the retaining instrument  10  in the receiving position according to  FIG. 3  and  FIG. 9  shows a side view of the functional end along the IX-IX line in  FIG. 8 . 
         [0044]    As shown in  FIGS. 7 ,  8  and  9 , both actuation segments  22 ,  24  of the two arms  14 ,  16  are each arch-shaped and inside each comprise a circular-arch shaped groove  40 ,  42 . The two grooves  40 ,  42  open outward in the region of the slot  30  and thereby clear a view of the plate retaining mechanism  26  incorporated between the two actuation segments  22 ,  24 . 
         [0045]    The plate retaining mechanism  26  comprises a support member in the form of a split ring  50  with a through-hole  62 . The split ring  50  is elastically deformable. More specifically, the two free portions of the split ring  50  can be compressed towards one another. 
         [0046]    Two plate retaining jaws  54 ,  56  are disposed on the split ring  50  on opposite sides of the through-hole  52 . The plate retaining jaws  54 ,  56  are arched and likewise each have an arched groove on their inner surface for receiving plates  58 ,  60 . In the present embodiment, the contouring of the grooves  58 ,  60  is selected in accordance with the outer contour of a bone plate that is to be grasped. 
         [0047]    The split ring  50 , which serves as a support member for the plate retaining jaws  54 ,  56 , is incorporated so that it can rotate freely in the grooves  40 ,  42  of the actuation segments  22 ,  24 . In so doing, the maximum spacing that the two actuation segments  22 ,  24  can achieve when the retaining instrument  10  is fully opened is selected in such a way that the split ring  50  (and therefore the plate retaining mechanism  26 ) is incorporated between the two actuation segments  22 ,  24  so that it is irremovable. 
         [0048]    The plate retaining mechanism  26  further comprises a cylindrical sleeve  62 , which is designed to be concentric to the through-hole  52  of the split ring  50 . The cylindrical sleeve  52  is attached in the region on the split ring  50  that is the right retaining jaw  54  in  FIG. 7 . The cylindrical sleeve  62  serves to accommodate the drill sleeve  70  shown in  FIG. 10  with a frictionally engaged connection.  FIG. 11  shows the retaining instrument  10  grasping a bone plate  80  and with an inserted drill sleeve  70 . 
         [0049]    The following will explain the functioning of the retaining instrument  10  in greater detail. Here, it is assumed, by way of example, that the retaining instrument  10  is being used for a transbuccal treatment of a jaw bone. Other uses should not thereby be excluded. 
         [0050]    Linear bone plates, like the bone plate  80  schematically shown in  FIG. 11 , are generally used for the surgical treatment of jaw bones. The bone plate  80  in the embodiment according to  FIG. 11  has four through-holes for bone screws, disposed along a straight line. The bone plate  80  has a bulge in the region of each through-hole. Two adjacent bulges are connected to one another by means of a bridge section. As mentioned above, the bulged contouring of the grooves for receiving plates  58 ,  60  provided in the plate retaining jaws  54 , is selected in accordance with the bulged outer contour of the bone plate  80  in the region of a through-hole. 
         [0051]    Starting from the release position of the retaining instrument  10  according to  FIGS. 1 and 7 , the bone plate  80  is positioned in a first step between the two plate retaining jaws  54 ,  56  in such a way that the plate retaining jaws  54 ,  56  are disposed in the region of a bulge in the bone plate  80  so that it can be grasped. The through-hole formed in the bone plate  80  for the bone screw is, in this case, disposed so that it is approximately concentric to the through-hole  52  of the split ring  50  as well as to the through-hole of the cylindrical sleeve  62 . 
         [0052]    The mutual spacing between the two plate retaining jaws  54 ,  56  in the release position is selected in such a way that the bone plate  80  can be clamped between the two plate retaining jaws  54 ,  56 . In the clamped state, the bone plate  80  is subject to some play, but is disposed between the two plate retaining jaws  54 ,  56  so that it is irremovable. In this state, the surgeon can freely rotate the bone plate  80  in relation to the arms  14 ,  16  and align the plate in relation to the jaw bone being treated (and relative to the retaining instrument  10 ) according to surgical necessity. 
         [0053]    In order to finally grasp the bone plate  80  thus positioned, the two arms  14 ,  16  of the retaining instrument  10  are subsequently moved towards each other while activating the locking device  28 . In this context, the actuation segments  22 ,  24  also move towards one another while compressing the split ring  50 . The resisting force associated with the compression of the split ring  50  acts on the serrated segments  38 ,  40  of the locking device  28  in such a way that the mutual position of the arms  14 ,  16  and therefore of the plate retaining jaws  54 ,  56  is locked, free of play. 
         [0054]      FIGS. 3 ,  8  and  11  illustrate the resulting plate-receiving position of the retaining instrument  10 , wherein, in  FIGS. 3 and 8 , the bone plate  80  is not shown for the sake of clarity. 
         [0055]    The compression of the split ring  50  by means of the arms  14 ,  16  causes a movement of the two retaining plate jaws  54 ,  56  towards one another and consequently, a clamping of the bone plate  80  disposed between the two plate retaining jaws  54 ,  56 . Moreover, the compression of the split ring  50  increases the force fit or the frictional connection between the split ring  50  as well as the actuation segments  22 ,  24 , which accommodates and holds the split ring  50 . For this reason, the split ring  50  and therefore the bone plate  80  being grasped as well, are fixed between the two actuation segments  22 ,  24  so that they are essentially rotationally fixed. 
         [0056]    In the receiving position, the rotatability of the split ring  50  in the receiving grooves  40 ,  42  of the actuation segments  22 ,  24  can be maintained to a limited extent. The surgeons can then (with increased force) still turn the grasped bone plate  80  with respect to the retaining instrument  10  to a certain extent, and finally align it according to surgical needs with respect to the jaw bone being treated. 
         [0057]    The drill sleeve  70  is placed over the cylindrical sleeve  62  either prior to or subsequent to grasping and aligning the bone plate  80 . In the receiving position, which is illustrated in  FIG. 11 , the through-holes of the drill sleeve  70 , of the cylindrical sleeve  62 , and as well as of the split ring  50  are disposed concentrically with respect to a through-hole of the bone plate  80 . 
         [0058]    In the next step, the bone plate  80  is positioned on the jaw bone via a transbuccal route using the retaining instrument  10 . A pilot hole is subsequently drilled using the drill, which is guided through the drill sleeve  70 . Subsequent to the formation of the pilot hole, a bone screw is introduced into the jaw bone through the drill sleeve  70 . The bone plate  80  is attached (at least temporarily) to the jaw bone using this bone screw. After the bone plate  80  has been attached, the locking device  28  is released by pivoting the two arms  14 ,  16  relative to one another in the region of the two finger holes  18 ,  20 . The two plate retaining jaws  54 ,  56  move away from one another due to the resisting force exerted by the compressed ring  50 , and the bone plate  80  is released. The plate retaining instrument  10  can then be removed from the surgical site via a transbuccal route. 
         [0059]    As is apparent from the above description of a preferred embodiment, the handling of the retaining instrument described here is made easier, since the surgeon can both grip the plate using a single hand, and manipulate the actuating mechanism in order to grasp and release the bone plate. Moreover, the actuating mechanism is manipulated at the distal end of the retaining instrument facing away from the surgical field. This fact further facilitates the handling of the retaining instrument. However, other implementations of the plate retaining instrument presented here are conceivable, which do not or do not fully realize these aspects. Moreover, numerous developments of the plate retaining instrument are possible. Thus, for example, a light source could be provided on the retaining instrument (fiber optic, for example), which would illuminate a region around the actuation segments  22 ,  24 .