Patent ID: 8535356
Filing Date: 2013-09-17
Classification: A61B

Abstract:
1. 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 defined by a plurality of internal walls, respectively, said plurality of apertures being adapted to receive said plurality of screws, respectively, said plate further comprising a plurality of screw head receiving areas associated with said plurality of apertures, respectively, for receiving at least a portion of said screw head after said screw is screwed into bone, said plate further comprising a plurality of detent surfaces associated with and extending into said plurality of screw head receiving areas, respectively; said at least a portion of said screw head comprising a plurality of compressible portions that are compressible when said screw is screwed into bone and expandable after it is received in at least one of said plurality of screw head receiving areas; said at least a portion of said screw head having or defining at least one screw surface that cooperates with at least one of said plurality of detent surfaces after said at least a portion of said screw head has been received in said plurality of screw head receiving areas to facilitate preventing said screw from withdrawing from said plate; a tool having a working end having an interior wall defining a working opening with said interior wall having a fixed shape without moveable parts and being adapted to compress said plurality of compressible portions to a compressed position when said plurality of compressible portions are received in said working opening; wherein said plurality of compressible portions cooperate, after being received in said working opening and compressed to said compressed position by said internal wall, to define a driving surface that can be rotatably driven by said internal wall in response to rotation of said tool in order to screw said screw into bone; said plurality of compressible portions being compressed by said internal wall when said screw is screwed into bone and thereafter expandable after said screw is screwed into bone and said tool removed from said screw head so that said at least one screw surface can cooperate with said at least one of said plurality of detent surfaces to retain said screw in said plate; said fixed shape generally complementing a shape of said driving surface.