Patent ID: 9414863
Filing Date: 2016-08-16
CPC Classification: A61B

Claim Text:
1. A polyaxial bone screw assembly comprising: a) a bone screw shank having an upper portion; b) a receiver having a cavity, the bone screw upper portion being receivable in the cavity; c) a retaining and articulating structure receivable in the cavity between the shank upper portion and the receiver, the retaining and articulating structure being unattached to both the shank and the receiver so as to be freely movable relative to both the shank and the receiver during positioning of the shank relative to the receiver; d) a compression insert disposed in the receiver during final positioning of the shank to lock the shank in place, the insert having a depression formed in an outer surface thereof and having a mating surface exclusively frictionally engageable with the bone screw upper portion, wherein the insert is spaced from the retaining and articulating structure; and e) resilient structure extending from the receiver and biasing against the compression insert at the depression thereof, the resilient structure resisting rotational movement of the compression insert within the receiver to maintain a desired alignment of the insert with the receiver, while allowing for upward and downward movement of the insert with respect to the receiver.