MODULAR TENSIONED SPINAL SCREW

A modular tensioned spinal screw comprises a bone fastener having a threaded elongate shaft and a spherical head at an upper end of said shaft. A modular yoke for polyaxial attachment to the head of said bone fastener has an inner bore, an upper end configured to receive a connecting rod and a lower end configured to receive the head of the bone fastener. An axially movable radially expandable socket collar, and a saddle having a rod receiving cradle are supported within the yoke bore. A retention pin fixed to the yoke movably supports the saddle and a tension member within the bore. The tension member comprises a resilient biasing element oriented such that upward axial movement of the saddle produces a downward bias force on said saddle to compress the head of the bone fastener between said saddle and said socket collar in a provisional holding position.