POLYAXIAL BONE ANCHOR WITH INSERT GUIDES

摘要

A polyaxial bone anchor with a receiver, a shank, a pressure insert, a retainer for holding the shank in the receiver, and a closure. The receiver having at least one vertically aligned guide on a surface of an interior shank and insert receiving chamber. The insert having at least one shoulder that aligns with the guide and both properly positions the insert relative to the receiver during assembly and prevents the insert from axially rotating relative to the receiver.

主权项

1. A bone anchor assembly comprising:
a shank, a receiver with a central axis receiving the shank and a pressure insert for applying pressure to the shank to lock the shank in a fixed position relative to the receiver; wherein: a) the insert includes at least one axially aligned shoulder; and b) the receiver includes at least one guide structure that mates with the shoulder so as to guide the insert into the receiver during assembly and so as to prevent axial rotation of the insert relative to the receiver.