Screw implant and system and method for locking a screw in an implant plate

Abstract

A plate system and method comprising a plate and a screw having an integral resilient lock. The screw comprises a head that has a portion that is adapted to be compressible as it is screwed into bone using a tool. After the screw head is received in the plate and the tool is removed therefrom, the screw head decompresses or expands into a locking or receiving area, thereby locking the screw in the plate. The plate is adapted to have at least one or a plurality of detents or lips for cooperating with at least a portion of the screw head to retain the screw in the plate and prevent it from withdrawing therefrom.

1 . An implant system comprising:
 at least one screw having:   a screw body having a longitudinal slot or aperture along an axis of said screw body to define a plurality of resilient members;   each of said plurality of resilient members comprising an internal wall defining a flexible member aperture, at least a portion of said internal wall defining a camming surface;   said flexible member aperture of said plurality of resilient members cooperating to define a tool insertion aperture having a predetermined aperture shape;   a tool having a working surface having a predetermined tool shape in cross section that generally complements said predetermined tool aperture shape;   said working surface of said tool engaging said camming surface and causing said plurality of resilient members to assume a compressed position.   
     
     
         2 . A plate system comprising:
 a plurality of screws, each of said plurality of screws having a shank and a screw head;   a plate having a plurality of apertures for receiving said plurality of screws, respectively, said plate further comprising a plurality of detents associated with said plurality of apertures, respectively;   at least a portion of said screw head being adapted to be compressible when said at least one of said plurality of screws are screwed into bone and expandable so that it can be received in at least one of a plurality of screw head receiving areas;   said at least a portion of said screw head cooperating with at least one of said plurality of detents to restrict or prevent said at least one of said plurality of screws are from withdrawing from said plate.   
     
     
         3 . The plate system as recited in  claim 2  wherein said plate system further comprises a tool having a working surface for compressing said at least a portion of said screw head after said at least a portion of said screw head receives said working surface. 
     
     
         4 . The plate system as recited in  claim 3  wherein at least a portion of said screw head of each of said plurality of screws comprises a plurality of resilient portions having receiving areas that cooperate to define a female opening for receiving said working surface. 
     
     
         5 . The plate system as recited in  claim 4  wherein said plurality of resilient portions each comprise an inner wall that defines said receiving areas that have a camming surface, respectively, said camming surface being engaged by at least a portion of said working surface of said tool when said tool is inserted into said female opening. 
     
     
         6 . The plate system as recited in  claim 2  wherein said plate system further comprises a tool having a working surface, said at least a portion of said screw head comprising a plurality of resilient portions each comprising an inner wall, at least a portion of said inner wall defines a camming surface that is adapted to be engaged by said working surface of said tool to drive said plurality of resilient portions together to a compressed position when said tool is inserted into said screw head, said compressed position enabling said screw head to clear said at least one of said plurality of detents when said screw is inserted into said plate. 
     
     
         7 . The plate system as recited in  claim 3  wherein each of said plurality of screws comprise a plurality of resilient portions, each of which are elastic or resilient and have an inner wall that defines a projection opening, said projection openings of said plurality of resilient portions cooperate to define a female opening for receiving said working surface, at least a portion of said inner wall defining a camming surface that is adapted to be engaged by said working surface of said tool when said tool is driven axially into said female opening until said plurality of resilient portions are in a compressed position, said compressed position being dimensioned such that said screw head clears said at least one of said plurality of detents when said screw is inserted into said plate. 
     
     
         8 . The plate system as recited in  claim 7  wherein each of said inner walls are generally U-shaped in cross-section. 
     
     
         9 . The plate system as recited in  claim 7  wherein said working surface of said tool comprises a beveled or curved surface for engaging said camming surface and for causing said plurality of resilient portions to assume said compressed position. 
     
     
         10 . The plate system as recited in  claim 9  wherein each of said inner walls comprises a curved or beveled surface adapted to facilitate introducing said working surface of said tool into said female opening and for engaging said camming surface. 
     
     
         11 . The plate system as recited in  claim 7  wherein said working surface of said tool comprises a beveled or curved surface for engaging said camming surface and each of said inner walls comprises a curved or beveled surface adapted to facilitate introducing and guiding said working surface of said tool into engagement with said camming surface. 
     
     
         12 . The plate system as recited in  claim 7  wherein said plurality of resilient portions are normally in an unbiased or undeflected home position when said tool is not inserted into said screw head so that after said screw head clears said at least one of said plurality of detents and said tool is removed from said female opening, said plurality of resilient portions return to said unbiased or undeflected home position, whereupon at least a portion of at least one of said plurality of resilient portions becomes operatively associated with at least one of said plurality of detents, thereby locking said screw in said plate. 
     
     
         13 . The plate system as recited in  claim 6  wherein each of said camming surfaces extends generally radially inwardly toward an axis of said screw. 
     
     
         14 . The plate system as recited in  claim 6  wherein said inner wall is non-circular and comprises at least one raised or inwardly-projecting projection surface that defines said camming surface. 
     
     
         15 . The plate system as recited in  claim 5  wherein when said plurality of resilient portions are driven toward each other and into a compressed position, said screw head clears said at least one of said plurality of detents when said screw is inserted into said plate. 
     
     
         16 . The plate system as recited in  claim 3  wherein said screw head comprises a plurality of screw head portions each having a female opening, said female opening cooperating to define a female working opening for receiving a tool such that when said tool is inserted into said female working opening said plurality of screw head portions are driven together to a compressed position. 
     
     
         17 . The plate system as recited in  claim 6  wherein said inner wall is not circular and defines or provides a plurality of inner walls in said plurality of resilient portions, respectively, said plurality of inner walls having a plurality of camming surfaces, respectively, that may be engaged by a plurality of working portions of said working surface of said tool when said tool is inserted into a female working opening, thereby driving said plurality of screw head portions together. 
     
     
         18 . The plate system as recited in  claim 17  wherein each of said plurality of inner walls is generally U-shaped or Omega-shaped in cross section. 
     
     
         19 . The plate system as recited in  claim 16  wherein said female working opening defines a predetermined shape. 
     
     
         20 . The plate system as recited in  claim 19  wherein said predetermined shape is a figure eight or bowtie shape. 
     
     
         21 . The plate system as recited in  claim 17  wherein said tool comprises a predetermined shape in cross section that is adapted to have engaging surfaces for engaging said camming surfaces in order to drive said plurality of screw head portions to said compressed position. 
     
     
         22 . The plate system as recited in  claim 21  wherein said tool predetermined shape is a figure eight or bowtie shape in cross section. 
     
     
         23 . The plate system as recited in  claim 4  wherein said plurality of detents comprise a plurality of undercut walls, respectively, that define a plurality of undercuts associated with said plurality of apertures, respectively, each of said plurality of undercut walls defining a receiving area for receiving at least a portion of said plurality of resilient portions. 
     
     
         24 . The plate system as recited in  claim 4  wherein each of said plurality of detents defines a generally U-shaped wall that defines an undercut associated with each of said plurality of apertures, said generally U-shaped wall defining a generally U-shaped receiving area for receiving at least a portion of said plurality of resilient portions. 
     
     
         25 . The plate system as recited in  claim 2  wherein said screw head comprises a concaving or separating area that defines each of a plurality of elongated members, each of said plurality of elongated members being resilient, elastic or movable so that they can be moved toward each other in response to axial insertion of a working surface of a tool into said screw head. 
     
     
         26 . The plate system as recited in  claim 16  wherein said plurality of screw head portions comprises inner walls that cooperate to define a female working opening, said inner walls also having at least one camming surface that engages and are driven by a working surface of said tool to a compressed position when said working surface is inserted axially into said female working opening. 
     
     
         27 . The plate system as recited in  claim 26  wherein said plurality of screw head portions extend generally longitudinally and parallel to an axis of said shank. 
     
     
         28 . The plate system as recited in  claim 27  wherein said plurality of screw head portions comprises a first portion that generally opposes a second portion. 
     
     
         29 - 86 . (canceled)