Patent ID: 9155581
Filing Date: 2015-10-13
Classification: A61B

Abstract:
1. A surgical screw assembly comprising: a fastener including an elongate shaft having a proximal end and a distal end and a head at said proximal end, said head having an external surface; a tulip having a tulip proximal end portion, a tulip distal end portion, an external surface and an internal bearing surface, said tulip distal end having a bore therethrough defining said internal bearing surface and having a diameter dimensioned to allow said distal end of said elongate shaft to pass therethrough; and locking enhancement features configured to cooperate with said head; wherein, in an unlocked configuration, said head is movable relative to said tulip and said locking enhancement features, and contacts a first subset of said locking enhancement features but does not contact a second subset of said locking enhancement features; in a provisionally locked configuration, said locking enhancement features engage said head with a first polyaxial grip strength; and in a finally locked configuration, said locking enhancement features engage said head with a second polyaxial grip strength, said second polyaxial grip strength being greater than said first polyaxial grip strength.