| 主权项 |
1. A bone anchor assembly comprising:
a bone anchor having a proximal head and a distal shaft configured to engage bone, a receiver member for receiving a spinal fixation element to be coupled to the bone anchor, the receiver member having
a proximal end having a pair of spaced apart arms defining a recess therebetween,a distal end having a distal end surface defining opening through which at least a portion of the bone anchor extends, a bearing positioned in the distal end of the receiver member and receiving the proximal head of the bone anchor, at least a portion of the bearing interposed between the proximal head of the bone anchor and the distal end surface of the distal end of the receiver member, an insert positioned in the proximal end of the receiver member, the insert having a pair of spaced apart insert arms defining a recess therebetween, the recess being sized and shaped to receive a spinal fixation element, each insert arm aligned with and positioned against an interior surface of a respective arm of the receiver member, the insert including an annular shaped distal end, the annular shaped distal end being positioned about a portion of the bearing and engaging the bearing when the spinal fixation element is fixed to the receiver member, and a closure mechanism positionable between and engaging the insert arms to capture a spinal fixation element within the recess of the insert and fix the spinal fixation element with respect to the receiver member. |
