A spine stabilization system having collars, resilient inserts and pins for coupling a rod to bone fasteners. A bone fastener may be advanced into a vertebral body. A first collar having a set of deflectable arms and a channel in a first end and an opening in the second end recessing to form a cavity may be positioned with the head of the bone fastener in the cavity. A rod may be advanced into the channel in the first end of each collar. The deflectable arms may have a set of recessed portions. The recessed portions may have an angular or arcuate profile. A resilient insert may be advanced into the collar and positioned in the recessed portions, with the bottom surface of the resilient insert in contact with the rod. A pin may be inserted in the resilient insert to inhibit removal of the resilient insert.