A system for percutaneously fixing a connecting rod to vertebrae comprises first and second bone screws, each with a corresponding hollow bone screw extension mounted thereto, and a connecting rod of length sized for subcutaneous receipt in the yokes of the bone screws. A rod introducer is provided for inserting the connecting rod into slots of the screw extensions and into the yokes of the bone screws. A rod persuader may also be provided that is attachable to at least one of the screw extensions, the rod persuader being operable to engage the connecting rod and urge the rod into the slot of the yoke of the corresponding bone screws. A rod detector may also be provided for insertion one of the screw extensions, the rod detector having an indicator sensing the presence of a rod in the slot of the yoke of at least one of the bone screws.