COUPLING ASSEMBLY FOR COUPLING A ROD TO A BONE ANCHORING ELEMENT, KIT OF SUCH A COUPLING ASSEMBLY DIFFERENT ROD RECEIVING ELEMENTS AND BONE ANCHORING DEVICE

摘要

An instrument for inserting a bone anchoring element into a bone is provided, the instrument including a shaft (2) having an end portion (23, 23′) for engaging the bone anchoring element and for transferring torque to the bone anchoring element (1, 1′) and a longitudinal axis defining an axis of rotation (R);
a cutting member (4, 4′) connected to the shaft (2) with cutting portions (45) that are configured to cut bone material;wherein the cutting member (4, 4′) has an outer diameter (D) defined by the cutting portions (45) that is substantially the same or larger than an outer diameter (dd) of a receiving part (500) of the polyaxial bone anchor in a region at a bottom end (500b) of the receiving part.

主权项

1. A coupling assembly for coupling a rod to a bone anchoring element, the coupling assembly comprising:
a receiving part having a first end, a second end and a central axis extending though the first end and the second end, a recess for receiving a rod, and an accommodation space for accommodating a head of a bone anchor, the accommodation space having an opening at the second end for inserting the head; a pressure element configured to be positioned at least partly in the accommodation space, the pressure element having a first end comprising a first end surface and a second end facing towards the second end of the receiving part, a central axis coaxial with the central axis of the receiving part, and a flexible portion to clamp an inserted head, a rod receiving element that is a separate part comprising a first end comprising a first end surface and a channel for inserting a rod adjacent to the first end and a second end having a second end surface facing towards the second end of the receiving part, wherein the first end surface projects over an upper surface of an inserted rod; wherein the first end surface of the pressure element is configured to extend into the channel of the rod receiving element; and wherein the pressure element comprises a portion that is configured to cooperate with a portion of the rod receiving element under axial load such that the portion of the pressure element or the portion of the rod receiving element or both are deformed so as to move the first end surface of the pressure element further into the channel of the rod receiving element in an axial direction.