Screw locking systems for bone plates

Abstract

Bone screws have heads which are provided with a hex socket as well as a threaded portion. A screw driver system includes a hex driver and a threaded driver. The screw driver system permits driving the screw through a plate system into a bone until desired compression is obtained. Then the screw is locked to the plate while maintaining the imparted compression.

1 . A screw driver system, comprising: 
 a first driver having an elongate body having a first end and a second end with a throughbore extending through said body from said first end to said second end and first screw engagement means for engaging a first portion of a screw located at said second end; and    a second driver having an elongate body having a first end and a second end and dimensioned to fit through said through bore of said first driver and second screw engagement means for engaging a second portion of a screw located at said second end of said second driver.    
     
     
         2 . The screw driver system according to  claim 1 , wherein: 
 said first screw engagement means includes means for locking the screw to the first driver and said second screw engagement means includes means for unlocking the screw from the first driver.    
     
     
         3 . The screw driver system according to  claim 1 , wherein: 
 said first screw engagement means is threaded and adapted to engage a threaded portion of a screw head.    
     
     
         4 . The screw driver system according to  claim 3 , wherein: 
 said first screw engagement means is an exteriorly threaded cylinder adapted to engage an interior threaded portion of the screw head.    
     
     
         5 . The screw driver system according to  claim 3 , wherein: 
 said first screw engagement means is an interiorly threaded cylinder adapted to engage an exterior threaded portion of the screw head.    
     
     
         6 . The screw driver system according to  claim 1 , wherein: 
 said second screw engagement means is a socket driver adapted to engage a socket in a screw head.    
     
     
         7 . The screw driver system according to  claim 6 , wherein: 
 said socket driver is a hex driver.    
     
     
         8 . The screw driver system according to  claim 1 , further comprising: 
 means for releasably locking said first and second drivers relative to each other.    
     
     
         9 . A bone screw, comprising: 
 a threaded shank having a first end, a second end, and an overall diameter;    a screw head having a portion of larger diameter than said overall diameter, said screw head defining two separate driver engagement means for engaging two separate screw drivers.    
     
     
         10 . The bone screw according to  claim 9 , wherein: 
 said two separate driver engagement means includes a threaded portion of said screw head and a socket portion of said screw head.    
     
     
         11 . The bone screw according to  claim 10 , wherein: 
 said threaded portion includes threads located inside said screw head.    
     
     
         12 . The bone screw according to  claim 10 , wherein: 
 said screw head has an outer surface and said threaded portion includes threads on said outer surface.    
     
     
         13 . The bone screw according to  claim 10 , wherein: 
 said threaded portion is coaxial with said socket portion.    
     
     
         14 . The bone screw according to  claim 10 , wherein: 
 said socket portion is a hex socket.    
     
     
         15 . The bone screw according to  claim 9 , wherein: 
 said screw head has a frustroconical surface.    
     
     
         16 . The bone screw according to  claim 15 , wherein: 
 wherein said frustroconical surface is substantially smooth.    
     
     
         17 . The bone screw according to  claim 15 , wherein: 
 said frustroconical surface is threaded.    
     
     
         18 . The bone screw according to  claim 9 , wherein: 
 said screw head has a cylindrical surface.    
     
     
         19 . The bone screw according to  claim 18 , wherein: 
 said cylindrical surface is threaded.    
     
     
         20 . The bone screw according to  claim 18 , wherein: 
 said screw head has a pair of spaced apart circumferential edges.    
     
     
         21 . The bone screw according to  claim 20 , wherein: 
 said edges have different diameters.    
     
     
         22 . A bone plating kit, comprising: 
 a bone screw having 
 a threaded shank with a first end, a second end, and an overall diameter, and  
 a screw head having a portion of larger diameter than said overall diameter, said screw head defining two separate driver engagement means for engaging two separate screw drivers;  
   a screw driver system having 
 a first driver having an elongate body having a first end and a second end with a throughbore extending through said body from said first end to said second end and first screw engagement means located at said second end for engaging a first one of said driver engagement means, and  
 a second driver having an elongate body having a first end and a second end and dimensioned to fit through said throughbore of said first driver and second screw engagement means located at said second end of said second driver for engaging a second one of said driver engagement means; and  
   a bone plate having 
 at least one screw hole adapted to receive said screw and lockingly engage said screw head.  
   
     
     
         23 . The kit according to  claim 22 , wherein: 
 said screw hole is tapered.    
     
     
         24 . The kit according to  claim 22 , wherein: 
 said plate has a top and a bottom and said screw hole is threaded from said top to a location between said top and bottom.    
     
     
         25 . The kit according to  claim 22 , wherein: 
 said first and second drivers are releasably lockable to each other.    
     
     
         26 . The kit according to  claim 22 , wherein: 
 said first screw engagement means is threads and said second screw engagement means is a hex driver.    
     
     
         27 . The kit according to  claim 26 , wherein: 
 said threads are internal to said first driver.    
     
     
         28 . The kit according to  claim 26 , wherein: 
 said threads are external to said first driver.    
     
     
         29 . A method for attaching a plate to a bone with a screw through a hole in the plate, said method comprising: 
 attaching the screw to a driver;    inserting the screw through the hole in the plate;    driving the screw into a bone while biasing the plate against the bone with the driver but not the screw; and    releasing the screw from the driver while locking it to the plate.