Bone screw coupling assembly

A coupling assembly used to selectively couple a bone screw having an elongate shaft and a head to an elongate rod, the coupling assembly comprising:

• a coupling element having a top, a bottom, and a central axis extending substantially centrally through the top and bottom, wherein a portion of the coupling element defines a saddle with a first side having an exterior surface and a second side having an exterior surface, the saddle defines a rod receiving channel with a longitudinal axis substantially transverse to the central axis, and wherein the saddle comprises at least one gripping insert at least partially protruding into the rod receiving channel and configured for gripping the rod when positioned therein the rod receiving channel;
• wherein the saddle is configured to be biased toward the longitudinal axis to engage the elongate rod, thereby substantially retaining the elongate rod therein the rod receiving channel.