Abstract:
A surgical screw cartridge system apparatus and method is provided wherein the cartridge has a body for storing a plurality of surgical screws. A spring-biased plunger is positioned within the body for presenting the surgical screws head first to a driver. A tab within the body prevents removal of the surgical screws from the body in absence of a screwdriver.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to surgical screw systems utilized for the fixation of bones. 
       BACKGROUND OF THE INVENTION 
       [0002]    During surgical operations involving fixation of bones, it is highly desirable that a surgical screw system be provided that allows a loading of the surgical screw to a surgical screwdriver in a fast, efficient manner. 
       SUMMARY OF THE INVENTION 
       [0003]    To make manifest the above noted and other manifold desires, a revelation of the present invention is brought forth. In a preferred embodiment, the present invention brings forth a surgical screw system that provides a surgical screw cartridge having a body for storing a plurality of surgical screws. A spring-biased plunger is provided within the cartridge body for presenting the surgical screws head first to a screwdriver. A tab is also provided which prevents removal of the surgical screw from the cartridge in the absence of the screwdriver. 
         [0004]    Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0006]      FIG. 1  is a sectional view of a preferred embodiment screw cartridge according to the present invention; 
           [0007]      FIG. 2  is an enlarged side elevational view of a surgical screw utilized in the screw cartridge system according to the present invention; 
           [0008]      FIG. 3  is an enlarged top plan view of the surgical screw shown in  FIG. 2 ; 
           [0009]      FIG. 4  is a view taken along line  4 - 4  of the screw cartridge shown in  FIG. 1  with a surgical screwdriver removed for clarity of illustration; 
           [0010]      FIG. 5  is an enlarged section perspective view of a surgical screw utilized with the present invention; 
           [0011]      FIG. 6  is a view taken along line  6 - 6  of  FIG. 1  of the screw cartridge according to the present invention; 
           [0012]      FIG. 7  is a view taken along line  7 - 7  of  FIG. 1  of the screw cartridge according to the present invention; and 
           [0013]      FIG. 8  is a view taken along line  8 - 8  of  FIG. 1  of the screw cartridge shown in  FIG. 1  of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0014]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
         [0015]    Referring to  FIG. 1 , the surgical screw system  7  according to the present invention has a cartridge  10 . The cartridge  10  has a body  12  which is typically fabricated from metal or plastic. The body  12  has an upper portion  14  with an upper central cavity  16 . The cavity  16  is provided for storage of a plurality of surgical screws  18 . 
         [0016]    The cartridge  10  also has a lower portion  19 . The cartridge lower portion  19  has a central cavity  20  generally aligned concentrically with the central cavity  16 . Slidably mounted within the cavity  20  is a plunger  22 . Typically, the plunger  22  is fabricated from metal or a plastic material. The plunger has a lower cylindrical alignment portion  24  slidably mounted within the cavity  20 . Connected on top of the plunger alignment portion  24  is an extended stem  26 . The plunger stem  26  has on its upper end a multi-diameter complex counterbore  28  to allow the plunger to hold the lowest surgical screw  18 . 
         [0017]    Biasing the plunger  22  to allow the plunger  22  to present a surgical screw  18  head first to a surgical driver  30  is a coil spring  34 . Retaining the coil spring  34  in position is a threadably connected lower body cap  36 . If desired, cap  36  can be screwed in or out to adjust the compression on the spring  34 . 
         [0018]    The body  12  has an upper portion  40  provided in part by an alignment cap  42 . The alignment cap  42  has a generally rectangular opening  44 . The opening  44  positionally aligns the driver  30  with a head  46  provided on the surgical screws  18 . 
         [0019]    The alignment cap  42  also has integrally connected thereto opposed tabs  50 . Tabs  50  have an upper neck portion  52  and a lower blocker portion  54 . The lower blocker portion  54  prevents removal of the screws  18  from the body  12  in the absence of the driver  30 . Upon the presence of the driver  30 , the driver  30  contacts the upper neck portion  52  causing the blocker portion  54  to be urged outwardly. 
         [0020]    The body  12  along its upper portion  40  also has two opposing rails  60 . The rails  60  have a semi-circular radially inward projecting edge  62 . The rails angularly positionally align the screws  18  with the body  12 . 
         [0021]    The screws  18  have, as mentioned previously, a head  46 . The screw head  46  is connected to a generally tapered threaded shank  66  ending in an optional self-drilling or self-tapping tip  68 . The screw  18  is typically fabricated from stainless steel, or titanium, or from a bio-absorbable or non-bio-absorbable plastic material. The screw head  46  has a Phillips or “crosshead” type drive, consisting of two generally perpendicular, crossing slots  70  and  72 , which are configured for reception of the driver  30  and provide a torsional interface therewith. It is apparent to those skilled in the art that other screw drive configurations can be utilized. The slots  70  and  72  have the same width and have generally conical cross-sectionally shaped floors  74  and  76 , respectfully. Separating the slots  72  and  70  are four cylindrical segments  78 . The top of the segments  78  have a slight chamfer  80  so as not to damage the threaded shank  66  of an adjoining screw. The cylindrical segments  78  (and the chamfer  80 ) form a primary surface of a stepped counterbore which accepts the threaded shank  66  of an adjoining screw while at the same time preventing contact of the tips  68 . The bottom of cylindrical segments  78  blend with, and the floors  74  and  76  intersect with, a cylindrical wall  81  that perpendicularly intersects with a generally annular flat  82  at an outer perimeter thereof. Intersecting the annular flat  82  at an inner perimeter thereof is a generally conical depression  84 . The conical depression  84  has a convergent angle that is greater than a convergent angle of the screw shank  66  adjacent the screw tip  68  to prevent possible wedging of the screw shank  66  with its lower adjacent screw. The conical depression  84  has a floor  86  which is dimensioned so that an adjoining screw  18  will contact the conical depression  84  without the tip  68  contacting the floor  86 . The above noted configuration of the conical depression  84  allows it to serve as a secondary contact surface between the adjacent screw in case there is a failure of the cylindrical segment  78  to fully hold up the adjacent screw  18 . A counterbore similar to that shown on  FIG. 5  with respect to the screw  18  is also provided by the counterbore  28  and the tip of plunger  22 , as generally shown in  FIG. 6 . The screw  18  also has an axial cylindrical segmented groove  88  that is operatively associated with the projecting edges  62  of the rails  60  to allow the rails to angularly position and align the screws  18  within the body  12 . 
         [0022]    In operation, a surgeon, or another medical profession assisting a surgeon, will take the screwdriver  30  and insert a blade of the screwdriver into the opening  44  provided by the cartridge  10 . As will be readily apparent to those skilled in the art, in some instances, it will be more convenient for the surgeon or the medical assistant to take the cartridge  10  by hand and stick it up over the driver  30 . The driver  30  will be aligned with the screws  18  inside the cartridge  10  by the opening  44 . The screws  18  within the driver  30  will be held within a stack. Typically, the cartridge  10  will contain five to six surgical screws. The plunger  22  is biased by the spring  34  to allow the plunger  22  to urge the screws  18  head-first toward the driver  30 . The screws  18  will be angularly aligned within the driver  30  by the opposing rails  60 . In the absence of the driver  30 , the blocker portion  52  of the tabs  50  will prevent removal of the screws  18  from the driver  30 . Upon insertion of the driver  30  within the cartridge  10 , the driver  30  contacts the upper neck portion  52  of the tabs  50  causing the blocker portions  54  to be moved outwardly. The coil spring  34  is then free to urge or accelerate the plunger  22  towards the driver  30  and in some applications, acceleration of the screws  18  toward the driver  30  generates a confirmatory auditory click and/or tactile vibration signal, thereby allowing the surgeon to recognize that the surgical screw is now contacted with the driver. The driver  30  can in some applications continue to be advanced into cartridge to further insure complete engagement of screw  18  with the driver  30 . The driver blades  90  and  92  are sized relative the slots  70  and  72  of the screw to allow the driver blades  90  and  92  to connect with the screw with a slight interference fit for connecting the screw to the driver  30 . After the screw  18  is connected with the driver  30 , the surgeon can then remove the screw loaded screwdriver and utilize the screwdriver in a surgical operation. Upon completion of torquing the screw  18  into a patient, the surgeon can then readily reload the next screw with the driver  30  by inserting the driver into the cartridge  10 . 
         [0023]    The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.