The present invention provides methods and devices for placing a spinal fixation rod into a rod receiving opening in a spinal anchor and installing a fastener to secure the rod to the spinal anchor. In one embodiment, the system can include a cap having a bore extending therethrough, an elongate drive rod that is adapted to extend through the bore, and a fastener that is disposed on a distal portion of the drive rod. The cap can include a driving element that is adapted to cooperate with a complementary driving element disposed on the rod to form a driving mechanism. Actuation of the driver mechanism can be effective to advance the drive rod through the cap to thereby reduce a spinal rod into a rod receiving opening of the spinal anchor and install the fastener to secure the rod to the spinal anchor.