CPC A61B 17/7037 (2013.01) [A61B 17/7035 (2013.01)] | 20 Claims |
1. A polyaxial bone anchoring device comprising:
an anchoring element having a shaft for anchoring in a bone and a head, the head comprising a spherically-shaped outer surface portion;
a receiving part configured to be pivotably connected to the head, the receiving part having a top end and a bottom end, a longitudinal axis extending through the top end and the bottom end, a channel transverse to the longitudinal axis for receiving a rod, and an accommodation space for accommodating the head;
a sleeve-like insert piece configured to pivot in the receiving part, the insert piece having a top end and a bottom end, and comprising a spherically-shaped exterior surface portion, a spherically-shaped seat configured to hold the head, and an inner tapered portion that widens as the inner tapered portion extends from the seat towards the top end of the insert piece; and
a pressure member positionable at least partially in the accommodation space;
wherein when the head, the insert piece, and the pressure member are in the receiving part and the head is held in the seat, the insert piece is tiltable with respect to the longitudinal axis of the anchoring element and with respect to a longitudinal axis of the receiving part to a position where the inner tapered portion directly contacts the pressure member, and the anchoring element is tiltable to substantially the same maximum pivot angle in every radial direction relative to the longitudinal axis of the receiving part while a rotational orientation of the insert piece relative to the receiving part remains constant; and
wherein the anchoring element and the insert piece are configured to be locked at respective angles relative to the longitudinal axis of the receiving part when the pressure member directly contacts the head and exerts pressure onto the head.
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