US Patent 12127765 Bottom loading polyaxial screw

A modular poly-axial bone screw includes a poly-axial bone screw, a poly-axial tulip head, and a collet disposed within the tulip head, the collet interacting with the bone screw and tulip head providing an interference fit with the bone screw head to lock orientation of the tulip head on and relative to the bone screw. Inner configurations of the tulip head interact with outer configurations of the collet to lock axial and/or rotational position of the collet within and relative to the tulip head, and thus about the bone screw head. The collet also has a base configured to conform to a top of a bone screw, wherein the collet is configured to support the bone screw and the tulip head when a spine rod is fixed in the tulip head.