Patent ID: 7875065

Claim:
A polyaxial bone screw assembly comprising: a) a shank having an elongate body and an integral upper portion, the body configured for fixation to a bone; b) a receiver having a top portion and a base, the receiver top portion defining an open channel, the base having a seating surface partially defining a cavity, the channel communicating with the cavity, the cavity communicating with an exterior of the base through an opening sized and shaped to receive at least the shank body therethrough; c) a retainer structure having at least two discrete parts, each part having a top surface, an inner surface and an outer surface, the inner surface configured to be in contact with the shank upper portion and the outer surface configured to be in polyaxially slidable engagement with the receiver seating surface when the retainer structure is captured between the shank upper portion and the seating surface, the shank upper portion having an upper end surface spaced above the retainer structure top surface; and d) a compression insert disposed within the receiver also spaced above the retainer structure and configured to frictionally engage the shank upper end surface.