Pop-on-cap assemblies having opposing splay-resisting features and generally reactangular opposing rotation-preventing/rotation-resisting features for spinal surgery

Abstract

A spinal-surgery system having a rod receiver and/or a cap having a generally cylindrical body, a set of opposing splay-resisting flanges, and a set of opposing rotation-preventing/rotation-resisting wings. Each wing has a lateral rotation-preventing portion and a lateral rotation-resisting portion. A receiver proximal end forms a wing-receiving cavity having a lateral rotation-preventing side and a lateral rotation-resisting side. Each flange has a proximal-facing splay-resist surface, and a distal-facing pop-on surface. Each receiver proximal protrusion has a proximal-facing sloped receiver pop-on surface, and a distal-facing sloped receiver splay-resist surface. Each rotation-preventing portion contacts a corresponding rotation-preventing side and each rotation-resisting portion contacts a corresponding rotation-resisting sides when the cap is popped on. The rotation-preventing portions contacting the rotation-preventing sides prevents cap rotation in a first direction. The rotation-resisting portion contacting the rotation-resisting side resists cap rotation in a second direction, but allows rotation in the second, forcing the arms to splay.