Abstract:
A bone screw system is disclosed. The bone screw system allows a bone screw to be inserted into a bone via a guide set with a plurality of pins. After the bone screw is inserted, a head portion of an extension member attached to the bone screw remains external to the wound such that the bone screw can be tightened later without re-opening the wound. The bone screw system is applicable to bone fractures, bone fusions, Osteomonies and other bone connectivity procedures. After healing, the bone screw may be left in the patient by removing an upper portion or the screw may be removed with additional incisions and a local anesthetic.

Description:
FIELD OF THE INVENTION 
       [0001]    The embodiments of the present invention relate to a bone screw system for helping bone fractures, fusions or Ostetomnies to mend. More particularly, the embodiments relate to a bone screw system comprising a bone screw and extension member having a portion which remains external to a patient&#39;s skin allowing the screw to be tightened without accessing the fracture, fusion or Osteotomy via an incision or other invasive procedure. The screw can be left in by detaching external components after healing or the screw may be removed in its entirety. 
       BACKGROUND 
       [0002]    The medical industry has no shortage of bone screws. Bone screws are implanted into patients to immobilize all types of bones fractures and fusions. Unfortunately, as patients undertake daily activities, the bone screws tend to loosen requiring them to be tightened. Tightening an implanted bone screw requires the bone fracture or fusion area to be accessed. In most instances, an incision is made, the bone screw is tightened and the incision is closed via stitches or a butterfly suture. Besides being stressful for patients, the incision procedure comes with risk. Infection and other side effects of the incision procedure make the procedure less than routine. 
         [0003]    Thus, there exists a need for a bone screw system that functions as well as implanted bone screws but allows bone screws to be tightened without any secondary invasive procedure on the patient. 
       SUMMARY 
       [0004]    Accordingly, one system embodiment of the present invention comprises: an elongated guide defining a passageway; and a bone screw having a threaded first end for insertion into bone and a second end adapted to engage a first end of a hollow extension member wherein a second end of said hollow extension member is adapted to remain external to a wound after insertion of the bone screw into the bone. 
         [0005]    Another system embodiment comprises: an elongated circular guide defining a passageway, said guide having multiple channels from a first end to a second end of a guide wall; guide pins adapted to extend along the channels, said pins having heads at a first end that prevent the guide pins from passing through the channels and second ends extending from said channels adapted to set the guide to bone; and a bone screw having a threaded first end for insertion into said bone and a second end adapted to engage a first end of a hollow extension member, a second end of said hollow extension member adapted to remain external to a wound and engage a tightening tool for tightening the bone screw. 
         [0006]    A first method embodiment of the present invention comprises: making an incision near bone; inserting a guide into said incision such that said guide is adjacent to the bone; setting said guide to the bone; drilling a cavity into said bone via a passageway in the guide; inserting a bone screw via said passageway into said bone such that one end of an attached hollow extension member remains external to the incision, said hollow extension member adapted to allow a tightening device to pass therethrough to engage said bone screw. 
         [0007]    In general, the bone screw of the present invention allows a bone screw to be inserted into a bone via the set guide. After the procedure is completed, a head portion of an extension member remains external to the wound such that the bone screw can be tightened later without re-opening the wound. 
         [0008]    Other variations, embodiments and features of the present invention will become evident from the following detailed description, drawings and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  illustrates an exploded view of various components of one bone screw system embodiment of the present invention; 
           [0010]      FIG. 1   a  illustrates an end view of a bone screw guide; 
           [0011]      FIG. 2  illustrates a perspective view of a bone screw, tightening device and plug; 
           [0012]      FIG. 3  illustrates a side view of the bone screw, tightening device and plug in a connected configuration; 
           [0013]      FIG. 4  illustrates a cross-sectional view along A of the bone screw, tightening device and plug in a connected configuration; 
           [0014]      FIG. 5  illustrates a side view of a head portion of the bone screw; 
           [0015]      FIG. 6  illustrates a top view of the head portion of the bone screw; 
           [0016]      FIG. 7  illustrates a side view of a threaded portion of the bone screw; 
           [0017]      FIG. 8  illustrates a perspective view of a countersink tool for countersinking a drilled cavity in a bone; 
           [0018]      FIG. 9  illustrates a side view of the countersink tool; 
           [0019]      FIG. 10  illustrates a top view of the tool for countersinking the cavity in the bone; and 
           [0020]      FIG. 11  illustrates a flow chart detailing one method of using one embodiment of the bone screw system of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    It will be appreciated by those of ordinary skill in the art that the invention can be embodied in other specific forms without departing from the spirit or essential character thereof. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive. 
         [0022]    While bone fractures are focused on below, bone fusions, Osteotomies and other bone connectivity procedures may benefit from the embodiments of the present invention as well. 
         [0023]    Initial reference is made to  FIGS. 1 and 2  illustrating an exploded view of components of one embodiment of a bone screw system of the present invention comprising a guide  100 , guide pins  110 , bone screw  120 , bone screw extension member  130  and bone drill bit  140 .  FIG. 1   a  shows an end view of the guide  100 . 
         [0024]    The guide  100  includes an elongated tube  101  defining a passageway  102  for allowing the bone screw  120  to insert into an incision and a handle  102 . A wall  103  of the elongated tube  101  includes, as shown, three channels  104  extending along a length of the tube  101 . In practice, after an incision is made near a bone fracture, the tube  101  is inserted into the incision so that it contacts a bone near the fracture. Then, as shown, three guide pins  110  are inserted into the channels  104  and are tapped so that sharpened ends  112  of the pins  110  enter the bone to temporarily set the guide  100  in place. Pin heads  111  prevent the pins  110  from passing completely through the channels  104 . Once the guide  100  is set, the bone drill bit  140  is used with a power drill to drill a starter cavity for entry of the bone screw  120 . 
         [0025]    The bone drill bit  140  also includes a bushing  141  designed to control the depth at which the drill enters the bone. Once the desired depth of drilling is known, the bushing  141  can be positioned accordingly to prevent inadvertent over-drilling. 
         [0026]    Once the cavity is drilled, the bone screw  120  is inserted into the passageway  102  and drilled through the fractured bone to secure two bone fragments together so that they may heal properly. However, it is well known that bone screws tend to loosen over time as the patient moves around and otherwise puts external forces on the fracture area. Therefore, tightening a bone screw requires a subsequent incision such that a tightening device can engage and tighten the bone screw. With the embodiments of the present invention, the length of the bone screw  120  and hollow extension member  130  is selected so that a head portion  131  of the extension member  130  remains external to the initial incision. 
         [0027]      FIGS. 2 through 4  show various views of the bone screw  120  and hollow extension member  130  separated and connected. The extension member  130  includes a threaded internal portion  131  which engages a threaded portion  121  of the bone screw  120 . The engagement of the bone screw  120  and extension member  130  remains internal to the wound and is therefore sterilized and sealed to prevent bacteria from entering the wound. Additionally, the threaded portion  131  of the extension member  130  and the threaded portion  121  of the bone screw  120  are machined with very accurate tolerances. Adhesive or a similar sealant may also be used to seal the connection between the extension member  130  and bone screw  120 . An opposite end of the extension member  130  includes a threaded plug  132  for sealing an opening  133 . The plug  132  has a hexagonal cavity  134  for receipt of an Allen wrench or similar tool for tightening the bone screw  120  after insertion. Alternatively, a hexagonal-shaped portion  134  of the extension member  130  allows a socket wrench or similar tool to be affixed temporarily thereto for tightening the bone screw  120  after insertion. 
         [0028]    Now referring to  FIGS. 5 through 7 , the aspects of the bone screw  120  are shown in detail.  FIGS. 5 and 6  show an upper threaded portion  121  of the bone screw  120  for engagement with the extension member  130 . The threaded portion  121  includes a hexagonal cavity  122  bored or otherwise formed therein. The hexagonal cavity  122  accepts an Allen wrench or similar tool for direct tightening of the bone screw  120 .  FIG. 7  shows a 60° self-tapping, threaded lower end  125  of the bone screw  120  that is used to penetrate bone. A flat spot  124  on the threaded lower end  125  of the bone screw  120  indicates a termination point of the threads. In one embodiment, adjacent threads are spaced 0.11 inches and the width of the threaded lower end  125  is 0.311 inches. Those skilled in the art will recognize that the bone screw  120  may be any suitable size dependent upon the procedure to be completed. 
         [0029]      FIGS. 8 through 10  show various views of an optional countersink tool  150  that is used after the bone drill  140  to countersink drilled holes to better accommodate the bone screw  120 . The countersink tool  150  also includes a depth bushing  151  to ensure that a resultant countersink does not inadvertently penetrate the bone too deeply. A diameter of the depth bushing  151  should be less than that of the passageway of the guide  100  to permit the countersink tool  150  to be used with the guide  100  in its set position. A handle  152  provides means for creating the necessary torque to countersink bone at the drilled hole locations. 
         [0030]      FIG. 11  illustrates a flow chart  400  detailing one method of using the bone screw system of the present invention. At  405 , an incision is made in the patient at the location of the bone fracture to be treated. Prior to the incision, the area is also treated with a providone-iodine topical antiseptic (e.g., Betadine®) to reduce the risk of infection. At  410 , the guide  100  is inserted into the incision such that the guide passageway rests over the bone fracture area to be treated. A guide handle  102  provides means for inserting the guide  100 . At  415 , three pins  110  are inserted into respective channels  103  in the guide wall  104  and set into the bone. At  420 , drill bit  140  and bushing  141  are used to drill a hole of appropriate depth into the bone. At  425 , the countersink tool  150  and depth bushing  151  are used to countersink the drilled hole to an appropriate depth. At  430 , the bone screw  120  and attached extension member  130  are inserted into the guide  100  and the bone screw  120  is screwed through the bone fracture such that the two sections of fractured bone are positioned for healing. At  435 , the plug  132  is used to seal of the hollow extension member  130 . At  440 , the guide  100  is removed from the incision. At  445 , after a passage of time, and likely at a follow-up status appointment with the surgeon, it is determined whether the bone screw  120  has loosened. If so, at  450 , an Allen wrench or similar device is inserted into the hexagonal cavity  134  of plug  132  and turned to tighten the bone screw  120  as desired. If not, at  455 , nothing need be done. The embodiments of the present invention eliminate the need to utilize follow-up invasive procedures to tighten bone screws. Therefore, the system of the present invention reduces patient stress associated with follow-up invasive procedures and reduces the risk of complications associated therewith. 
         [0031]    In addition, after healing, the screw can be left in by detaching an upper portion of the screw or the entire system may be removed. The upper portion may be removable (e.g., threaded) or cut off using appropriate tooling. 
         [0032]    Each of the components of each embodiment of the bone screw system of the present invention maybe fabricated of any suitable materials including metal alloys and composites. Ideally, the manufacturing process utilizes small tolerances to ensure the preciseness and operability of the system. 
         [0033]    Although the invention has been described in detail with reference to several embodiments, additional variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims.