Bottom-loading pedicle screw assembly

A spine screw assembly comprising:

• a fastener having an upper end and a lower end, a head at the upper end, and an anchoring element extending between the upper and lower ends, wherein a groove is positioned in the head of the fastener;
• a clip sized to be positioned in the groove, wherein the annular clip transitions between a first state of increased size and a second state of decreased size, and wherein the annular clip can be locked within the groove when in the second state of decreased size and can be removed from the groove by transitioning the first state of increased size;
• a coupling element having an upper opening at an upper end and a lower opening at a lower end, the coupling element including a rod receiving channel adapted to receive a stabilizing rod, a bore extending through the lower end of said coupling element for receiving said fastener, and a seat adapted to engage the head when the fastener is positioned in the bore;
• and
• a compression nut engageable with the coupling element, the compression nut adapted to rotatingly move distally into the coupling element to translate a force to the head of the fastener such that the head is forced against the seat of the coupling element to prevent relative movement between the fixation element and the coupling element.