Patent ID: 9522021
Filing Date: 2016-12-20
CPC Classification: A61B

Claim Text:
1. A polyaxial bone anchor assembly comprising: a) a shank having a body for fixation to a bone and an integral upper portion, b) an U-shaped receiver having a top portion and an integral base, the receiver top portion defining an open rod-receiving channel, the integral base defining a cavity communicating with a bottom opening, the bottom opening having at least one concave curved bottom surface, the integral upper portion of the shank positionable within the cavity, and the channel communicating with the cavity; c) a retainer positioned within the cavity prior to the shank being loaded and capturing the shank upper portion once loaded, the retainer being in a non-pivotal relationship with respect to the receiver; and wherein the retainer having a cut-out surface being sized and shaped to cooperate with the concave curved bottom surface of the receiver to provide for increased polyaxial motion in at least one direction for the shank with respect to the receiver.