An instrument for adjusting a fixation rod within a head member of a screw assembly includes a distal portion, a first arm, a first recess, and an actuation member. The distal portion includes a rod engagement surface that engages the fixation rod. The first arm extends from the distal portion towards the head member at a first angle. The first recess is disposed along the first arm at a first distance from the rod engagement surface. The actuation member extends proximally from the distal portion and positions the first recess relative to a first projection on the head member.
