Abstract:
A combined compressor and distractor tool is provided that includes a mechanism capable of switching the mode of operation of the tool from a compression tool to a distraction tool. The tool includes engagement tips and handles at opposed ends of the tool that are pivotally connected to a central shaft. A saddle is slidably mounted on the shaft between and pivotally connected to the handles. When the saddle is engaged with the shaft in a before center position, squeezing the handles results the movement of the shaft forwardly to operate the engagement tips as a distractor. However, when the saddle is engaged with the shaft in a past, or over center position, squeezing the handles results in the movement of the shaft rearwardly to operate the engagement tips as a compressor.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority as a divisional application from U.S. Non-Provisional patent application Ser. No. 12/123,006 filed on May 19, 2008, which in turn claims priority from U.S. Provisional Patent Application Ser. No. 60/938,638, filed on May 17, 2007, each of which are incorporated herein in their entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to a spinal compressor instruments and spinal distractor instruments and more particularly to an instrument combining the compression and distraction functions. 
       BACKGROUND OF THE INVENTION 
       [0003]    In order to perform a surgical procedure in which the separation of various physical components, such as spinal vertebrae, is required, a tool called a distractor is necessary for displacing the physical components from one another. The distractor operates by mechanically converting a compressive force exerted by an individual on a handle located at one end of the distractor into an opposite expanding movement for a pair of engagement tips of the distractor disposed opposite the handle. To accomplish this, the distractor is formed with a number of mechanical linkages that extend between the handles and the distractor tips. These linkages are pivotally connected to one another in a manner that converts the inward movement of the handles into outward movement of the distractor tips. 
         [0004]    In other situations or surgical procedures it is necessary to compress physical components towards one another. In these procedures, it is necessary to employ a tool called a compressor that operates by mechanically converting a compressive force exerted by an individual on a handle located at one end of the compressor into a corresponding compressive force for a pair of engagement tips on the compressor disposed opposite the handle. To perform this function, the compressor is most often formed with a simple scissors linkage such that an inward and compressive force on the handle is translated into an inward compressive force on the compressor tips. 
         [0005]    However, in many surgical procedures both a compressor and a distractor are necessary for proper completion of the procedure, and often times are utilized in the same location in which the procedure is performed. Because the compressor and the distractor are formed as separate tools, it is necessary to have both a compressor and a distractor available such that each tool can be utilized when required during the surgical procedure. For this reason, many kits for use in spinal procedures include both a compressor and a distractor in them. However, the requirement for having compressor and distractor tools present during a procedure can create problems with regard to a number of tools present during a surgical procedure, especially when one of the tools becomes contaminated, i.e., is dropped, and needs to be sterilized. 
         [0006]    As a result, it is desirable to develop a tool that can function as both a compressor and a distractor depending upon the particular situation in the surgical procedure being performed. 
       SUMMARY OF THE INVENTION 
       [0007]    According to one aspect of the present invention, a tool is provided that can function as either a compressor or a distractor depending upon the operative configuration of the tool. The tool is formed with a pair of engagement tips pivotally connected to a central member such that the tips can be moved laterally towards and away from one another due to the pivoting movement of the pivot arms with regard to the central member. Opposite the tips, the tool includes a pair of handles also pivotally connected directly to the central member for movement with respect to the central member. A central shaft is slidably disposed within and extends through a channel formed in the central member, such that opposite ends of the shaft are positioned between the tips and the handles. Between the tips, the shaft includes pairs of pivoting members connected to the shaft at one end and to the tips at the opposite end of each pivoting member. Between the handles, the shaft includes a saddle slidably mounted to the shaft and pivotally connected to the handles at locations spaced from the central member by additional pivot members. The saddle can be selectively engaged with the shaft at various locations on the shaft to position the saddle in either a before center or an over center location on the shaft. By moving the saddle between these locations, the tool is capable of mechanically translating the compressive force exerted on the handles into either a compressive or distraction force on the tips. 
         [0008]    According to another aspect of the present invention, the handles are connected to one another opposite the central member by an adjustable locking rod. The rod includes a spring-biased locking member that can be engaged with slide extending between the handles when the handles are positioned at any configuration along the slide with respect to one another. 
         [0009]    Numerous other aspects, features, and advantages of the present invention will be made apparent from the following detailed description together with the drawings figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The drawings illustrate the best mode currently contemplated of practicing the present invention. 
           [0011]    In the drawings: 
           [0012]      FIG. 1  is an isometric view of a convertible compressor/distractor tool constructed according to the present invention in a distraction configuration 
           [0013]      FIG. 2  is a side plan view of the tool of  FIG. 1 ; 
           [0014]      FIG. 3  is a partially broken away side plan view of the tool of  FIG. 1 ; 
           [0015]      FIG. 4  is a partially broken away side plan view of the tool of  FIG. 1  in an engaged position; 
           [0016]      FIG. 5  is an isometric view of the tool of  FIG. 1  in a compression configuration; 
           [0017]      FIG. 6  is a side plan view of the tool of  FIG. 5 ; 
           [0018]      FIG. 7  is a partially broken away side plan view of the tool of  FIG. 5 ; and 
           [0019]      FIG. 8  is a partially broken away side plan view of the tool of  FIG. 5  in an engaged position. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    With reference now to the drawing figures in which like reference numerals designate like parts throughout the disclosure, a convertible compressor/distractor tool constructed according to the present invention is indicated generally at  10  in  FIGS. 1 and 2 . The tool  10  includes a pair of tip members  12  at one end, each including a tip  14  and a body  16  extending from the tip  14 . The tips  14  can be integrally formed with the body  16  of each tip member  12 , or can be releasably secured thereto utilizing any suitable mechanism. The tips  14  can additionally be formed from materials different from that used in forming the body  16 , which normally is a metal, such as stainless steel, such that the tips  14  can be formed from plastics, such as transparent plastics that enable an individual to view objects through the tips  14  when the tool  10  is in use. Further, the releasable attachment of the tips  14  to the body  16  of the tip members  12  allows the tips  14  to be removed and replaced should they become damaged. 
         [0021]    Alternatively, the tool  10  can include only a single movable tip member  12 , with the tip member  12  movable with respect to a stationary member (not shown) to provide the compression or distraction function. 
         [0022]    Referring now to  FIGS. 4-7 , the tip members  12  are each pivotally connected by a pivot pin  18  to one end of a pair of the first pivot arms  20 . Opposite the tip members  12 , the pair of first pivot arms  20  are each pivotally connected by pivot pins  22  to a supporting central member  24 . However, in addition to pins  22 , the first pivot arms  20  can also be pivotally connected to the tip members  12  with other structures, such as members (not shown) that may slide and rotate within respect to the engagement tips  12  in order to allow the tip members  12  move and provide the different functionalities of the tool  10 . 
         [0023]    Opposite the tip members  12 , a pair of gripping handles  26  are each movably, and preferably pivotally connected to the central member  24  by pivot pins  28  or other suitable connectors. Alternatively, similar to the tip members  12 , the tool  10  can include only a single movable handle  26 , with the handle  26  movable with respect to a stationary member (not shown) to provide the compression or distraction function. 
         [0024]    The handles  26  are each formed of a generally rigid material, such as a metal, and preferably are formed with a shape that is conducive to easy gripping of the handles  26  by an individual. Opposite the central member  24 , the gripping handles  26  are connected to one another by a locking mechanism  30 . The locking mechanism  30  includes a slide or rod  32  connected, preferably pivotally, at one end to one of the gripping handles  26 , and slidably received within a bore  34  disposed in the opposite handle  26 . The rod  32  includes a stop surface  35  opposite the end of the rod  32  connected to one of the handles  26 . The stop surface  35  has a diameter greater than the diameter of the bore  34 , such that the stop surface  35  can engage the periphery of the handle  26  around the bore  34  to maintain the rod  32  within the bore  34 . 
         [0025]    Adjacent the bore  34 , the handle  26  having the bore  34  also includes a locking tab  36  pivotally connected to the end of the gripping handle  26  and including an aperture  38  therein through which the rod  32  extends. The rod  32  can slide through the aperture  38  formed within the tab  36  when the handles  26  are urged towards one another. 
         [0026]    A spring  40  is disposed about the rod  32  between the locking tab  36  and the gripping handle  26  in which the bore  34  is formed. The spring  40  operates to urge the tab  36  away from the handle  26  to misalign the aperture  38  with the rod  32 , thereby frictionally engaging the tab  36  with the rod  32  in order to retain the gripping handles  26  in a stationary position. The positioning of the spring  40  enables the handles  26  to be moved toward one another without resistance from the tab  36 , as the movement of the handles  26  toward one another opposes the bias of the spring  40 . However, when the handles  26  are released, the spring  40  pushes the tab  36  into the frictional engagement with the rod  32 , effectively locking the handles  26  in the current position. 
         [0027]    To disengage the locking mechanism  30 , the tab  36  is moved towards the handle  26  to which it is secured against the bias of the spring  40  to disengage the tab  36  from the rod  32 . This allows the handle  26  and tab  36 , along with the spring  40 , to slide along the rod  32  and move towards or away from the opposed gripping handle  26  to which the rod  32  is pivotally secured. With the locking mechanism  30 , it is capable to engage the gripping handles  26  in a stationary position with regard to one another at any relative position by allowing the tab  36  to engage the rod  32  at an infinite number of locations along the rod  32 . 
         [0028]    Also, the design of the locking mechanism  30  does not have any sharp edges, teeth or ridges, as in prior art distractors and compressors, such that the mechanism  30  is less likely to become damaged even during regular usage, and is less likely to damage the gloves worn by an individual utilizing the tool  10 . Preferably, the handle  26  to which the tab  36  is attached includes an inwardly extending flange  39  positioned generally parallel to the rod  32 . The tab  36  is secured to the flange  39  adjacent the innermost end of the flange  39  to give the tab  36  a significant range of motion in either direction with respect to the rod  32 . Also, the presence of the flange  39  functions as a guard to the tab  36 , such that inadvertent contact with the flange  39  or rod  32  will not be able to disengage the tab  36  from the rod  32 , maintaining the locked position of the handles  26 . 
         [0029]    Referring now to  FIGS. 1-8 , in order to mechanically translate the movement of the gripping handles  26  into corresponding compressive or distractive lateral movement of the tip members  12 , a central shaft  42  is positioned within and extends through a central channel  44  defined in the central member  24 . A first end  46  of the shaft  42  is positioned between and equidistant from each of the tip of members  12 . The shaft  42  also includes a pair of sets of pivot members  48  each pivotally connected at one end to the first end  46  of the shaft  42  via pivot pins  50  and  52  engaged with the first end  46 , and at the opposite ends to the tip members  12  via pivot pins  54 - 60 , though other suitable connections (e.g., sliding connections) can be made between the pivot members  48  and the shaft  42  and tip members  12 . In this configuration, as the shaft  42  slides through the channel  44  in the central member  24  in a direction towards the tip members  12 , the shaft  42  operates to urge the tip members  12  always from one another in a distractive moment as a result of the engagement of the tip members  12  with the shaft  42  via the sets of pivot members  48 . Conversely, as the shaft  42  slides through the channel in the central member  24  in a direction away from the tip members  12 , the shaft  24  pulls the sets of pivot members  48  and the tip members  12  towards one another in a compressive movement. 
         [0030]    Between the gripping handles  26 , the central member  24  includes a guide sleeve  62  secured to the central member  24  around the channel  44  and through which the second end  64  of the shaft  42  extends. The sleeve  62  ensures that the shaft  42  moves in a strictly linear fashion with regard to the remainder of the tool  10 . 
         [0031]    Disposed on the second end  64  of the shaft  42  is an operational shifting member or saddle  66 . The saddle  66  includes a central bore  68  through which the second end  64  of the shaft  42  extends. The saddle  66  is maintained in engagement with the shaft  42  by the sleeve  62  at one end, and by an end cap  70  secured to the second end  64  of the shaft  42  opposite the sleeve  62 . Additionally, the saddle  66  is urged away from the central member  24  by a spring  69  disposed within the sleeve  62  and engaged at one end by a ring  69   a  secured to and extending outwardly from the saddle  66  partially into the sleeve  62 , and by the central member  24  at the opposite end. The spring  69  functions to move the saddle  66  along the shaft  42  away from the central member  24  to move the tool  10  to the position shown in either  FIGS. 1 and 2 , or  FIGS. 5 and 6  when the locking mechanism  30  is disengaged. The saddle  66  is also pivotally connected by pivot pins  71  or any other suitable connection, to one end of a pair of pivot arms  72  that are each pivotally connected at the opposite end to the gripping members  26  at a location spaced from the rod  32  by pivot pins  73 . 
         [0032]    The saddle  66  also includes a locking device  74  disposed within the body of the saddle  66  that at least partially obscures the central bore  68  extending through the saddle  66 . The locking device  74  is selectively engageable with one of a number of notches  76  located in the second and  64  of the shaft  42  between the sleeve  62  and the end cap  70 . These notches  76  are disposed on opposite sides of the center point  77  of the second end  64  of the shaft  42 , such that the pivot arms  72  are either angled towards or away from the central member  24  when the saddle  66  and locking mechanism  74  engaged with these notches  76 . When these saddle  66  is engaged with a notch  76  closer to the central member  24 , as illustrated in the  FIG. 1 , the compression of the gripping handles  26  towards one another causes the shaft  24  to slide through the central number  24  towards the tip members  12 , causing the tip members  12  to move outwardly in a corresponding distraction movement. Conversely, when the saddle  66  is engaged with notch  76  closer to the end cap  70 , as shown in  FIG. 2 , the movement of the handle members  26  towards one another slides the central shaft  42  all way from the central number  24 , drawing the tip members  12  towards one another in a compressive movement. 
         [0033]    With the construction of the tool  10  according to the present invention, the amount of force required to move the handle members  26  towards one another is greatly lessened, such that the structural components of the tool  26  including the handle members  26  undergo less stress during operation of the tool  10 . Consequently, the materials utilized in the construction of the tool  10  can be selected from materials that are more lightweight than prior art compression tools and distraction tools. 
         [0034]    Additionally, as a result of the construction of the tool  10  with the central shaft  42  and the saddle  66 , the stroke and leverage of the tool  10  can be altered by varying the position of the saddle  66  with regard to the shaft  42  in each mode of operation of the tool  10 . This allows the power generated by the operation of the tool  10  to be varied by positioning the saddle  66  at the proper or desired location along the shaft  42 . Further, the operation of the tool  10  in either mode is not strictly linear, such that less force is required to move the handles  26  near the end of the stoke of the tool  10 . 
         [0035]    Various other embodiments of the present invention are contemplated as being within the scope of the filed claims particularly pointing out and distinctly claiming the subject matter regarded as the invention.