Patent ID: 7037309

Claim:
Self-tapping screw for small-bone surgery, particularly of the Barouk screw type, comprising: a threaded proximal head ( 2 ) with a screw thread; a threaded distal shank ( 3 ) with a screw thread, the pitch of the screw thread on the proximal head being shorter than the pitch of the screw thread of the distal shank; and an internal passage ( 4 ) in the manner of a cannula, the distal shank ( 3 ) threaded over its entire length to meet the threaded head ( 2 ), the distal end of the distal shank having milled portions forming angularly equidistant self-tapping faces ( 5 , 5 a , 6 , 6 a ) on first distal threads terminating portions of the screw thread of the distal shank, apart from the milled portions, at least two milled portions forming angularly equidistant faces ( 9 , 10 ) about the longitudinal axis of the screw that together with the internal passage determine at least two notches ( 11 ) in the terminal end of the internal passage, at least two self-boring cutting edges ( 5 b , 6 b ) at the distal end of the screw, the distal end of the screw thread of the head having first milled portions forming angularly equidistant self-tapping faces ( 12 to 15 , 12 a to 15 a ) on first threads of the proximal screw thread, aside the first milled portions, second milled portions forming angularly equidistant chamfered faces ( 16 – 19 ), the second milled portions determining boring edges ( 12 b – 15 b ); and a short groove ( 2 b ) preceding the boring edges and following the screw thread of the distal shank.