Polyaxial bone anchoring device with enlarged pivot angle

摘要

A polyaxial bone anchoring device includes a bone anchoring element having a shank and a head, a receiving part including a rod receiving portion, and a head receiving portion having a first end and an open second end with a bounding edge, wherein the head receiving portion is configured to be rotatably connected to the rod receiving portion and is flexible for introduction and clamping of the head, and a locking ring configured to be mounted around the head receiving portion, wherein the head is insertable into the head receiving portion from the second end, is pivotable in the head receiving portion at a larger maximum pivot angle relative to the receiving part at a first location of the bounding edge, and can be locked at an angle relative to the receiving part by compressing the head receiving portion with the locking ring.

主权项

1. A polyaxial bone anchoring device comprising:
a bone anchoring element having a shank for anchoring in a bone and a head; a receiving part for coupling a rod to the bone anchoring element, the receiving part comprising:
a rod receiving portion having a first end, a second end, and a recess with a bottom for receiving a rod therein; anda head receiving portion having a first end, an open second end with a bounding edge, and a hollow interior portion in communication with the second end for accommodating the head of the bone anchoring element, wherein a first region of the head receiving portion is insertable into the second end of the rod receiving portion to rotatably connect the head receiving portion to the rod receiving portion, and wherein the head receiving portion is flexible for introduction and clamping of the head; and a locking ring configured to be mounted around the head receiving portion; wherein when the head receiving portion is connected to the rod receiving portion and the locking ring is around the head receiving portion, the head is insertable into the head receiving portion from the second end of the head receiving portion, is pivotable in the head receiving portion such that the bounding edge is configured to permit the bone anchoring element to pivot at a larger maximum pivot angle relative to the receiving part at a first location of the bounding edge than at a second location of the bounding edge, and can be locked at an angle relative to the receiving part by compressing the head receiving portion with the locking ring; and wherein when the first region of the head receiving portion is in the rod receiving portion, at least one retaining element is insertable into the receiving part to connect the head receiving portion to the rod receiving portion.