Patent ID: 9155568
Filing Date: 2015-10-13
Classification: A61B

Abstract:
1. A bone anchoring device comprising: an anchoring element having a shaft for anchoring to a bone and a head, a receiving part having a longitudinal axis from a top end to a bottom end, a rod recess for receiving a rod therein, a coaxial bore extending from the top end in the direction of the bottom end and a seat for receiving the head near the bottom end, and a pressure element that is movable within the bore; wherein the head is pivotable with respect to the receiving part and configured to be fixed at an angle by exerting pressure via the pressure element onto the head when the anchoring element and the pressure element are in the receiving part; wherein the pressure element has an outer wall portion having a first feature, wherein the first feature is one of a recess or a projection and wherein the receiving part has an inner wall portion having a second feature, wherein the second feature is the other of a recess or a projection that cooperates with the first feature of the pressure element; wherein the pressure element is configured to assume a first position within the bore of the receiving part wherein the recess and the projection are engaged to allow the pressure element to exert a preload onto the head and the head is prevented from freely pivoting but is not locked; wherein the pressure element is movable along the longitudinal axis from an assembly position spaced from the bottom end of the receiving part wherein the recess and the projection are disengaged and the first feature is entirely above the second feature along the longitudinal axis to the first position closer to the bottom end of the receiving part wherein the recess and projection are engaged; wherein, when the pressure element is in the assembly position, the projection and the recess are disengaged, a portion of the projection and an opening to the recess are aligned along an axis parallel to the longitudinal axis and the portion of the projection and the opening radially overlap, and the head is capable of freely pivoting; and wherein the recess is inclined along the longitudinal axis such that when the pressure element is moved downward in the receiving part between the assembly position and the first position, a pressure force between the recess and the projection increases.