Patent attributes
A modular spinal fixation system for securing an elongate rod to a bone of a patient includes a plurality of bone anchors, each having a universal shank head and an anchor portion opposite the universal shank head configured for fixation to the bone. The system further includes a plurality of pivoting and non-pivoting receiver sub-assemblies, with each receiver sub-assembly including a receiver having an upper portion defining a channel configured to receive the elongate rod and a base defining a lower portion of a central bore communicating with a bottom surface of the receiver through a bottom opening, and one of a shank head-engaging retainer or a rod-engaging insert positioned within the central bore. Each of the universal shank heads is configured for uploading into both the pivoting and non-pivoting receiver sub-assemblies through the bottom opening of the receiver and for axial rotation about a longitudinal axis of the shank relative to the receiver prior to locking the receiver sub-assembly to the head of the shank with the elongate rod and a closure.