Bone anchor assembly with bone debris sweep ring in receiver sub-assembly

A bone anchor assembly for securing an elongate rod to a bone of a patient with a closure, the bone anchor assembly comprising:

• a bone anchor comprising a longitudinal axis, a capture portion, and an anchor portion opposite the capture portion configured for fixation to the bone, the capture portion including an upper slidable outer surface, a lower slidable outer surface, and a capture recess between the upper slidable outer surface and the lower slidable outer surface;
• a receiver comprising a base defining a lower portion of a central bore centered around a vertical centerline axis and communicating with a bottom of the receiver through a bottom opening, and an upper portion having a channel configured to receive the elongate rod, the central bore extending upward through the channel to a top of the receiver and including a seat surface adjacent the bottom opening;
• and
• a retainer sub-assembly positionable into the lower portion of the central bore of the receiver proximate the bottom opening, the retainer sub-assembly comprising:
• a ring retainer comprising an annular bottom surface, an outer surface, and a center aperture configured to receive the capture portion of the bone anchor;
• the center aperture including a lower internal recess and an upper internal recess;
• an open sweep ring positionable within the lower internal recess of the ring retainer and configured to sweep the capture recess of bone debris upon the uploading of the capture portion through the center aperture of the ring retainer;
• and
• an open capture ring positionable within the upper internal recess of the ring retainer and configured to snap into in the swept capture recess of the bone anchor to capture and hold the capture portion of the bone anchor to the ring retainer;
• wherein the outer surface of the ring retainer is configured for frictional engagement with the seat surface of the central bore to secure the retainer sub-assembly and the captured bone anchor to the receiver.