Bone anchoring device

摘要

A bone anchoring device for securement to a bone. The device includes an anchor, a receiver, a retainer and an insert. The receiver includes a seating surface defining a cavity communicating with the exterior of the receiver through a first opening configured to receive the connection head of the anchor therethrough. The retainer includes at least two discrete retaining members configured to engage with the receiver seating surface when they are captured between the connection head and the seating surface. The insert is disposed within the receiver and configured to frictionally engage the connection head. The insert includes a main body and at least one pin protruding from the main body, for circumferential insertion between two adjacent retaining members of the retainer.

主权项

1. A bone anchoring device comprising:
an anchor comprising a connection head and a bone anchoring part for fixation to a bone; a receiver having a top portion and a base, the base having a seating surface defining a cavity, the cavity communicating with an exterior of the receiver through a first opening at a lower end of the receiver, the first opening being configured to receive the connection head therethrough; a multi-piece retainer comprising at least two discrete retaining members unattached to each other, the retaining members being configured to engage with the receiver seating surface while a surface of each of the retaining members frictionally engages the connection head; and an insert disposed within the receiver, the insert comprising a main body configured to frictionally engage the connection head; wherein the insert comprises at least one pin protruding from the main body, each pin being configured for circumferential insertion between two adjacent unattached retaining members of the retainer, so as to hold the retaining members circumferentially spaced apart from each other, thus securing the retaining members inside the cavity.