An instrument for manipulating a spinal fixation element relative to a
bone anchor includes a bone anchor grasping mechanism, a first adjustment
mechanism, and a second adjustment mechanism. The bone anchor grasping
mechanism includes a first arm having a distal end configured to engage
an opening provided in the bone anchor. The first adjustment mechanism
includes a second arm pivotally connected to the first arm. The second
arm has a distal end configured to engage an opening provided in the bone
anchor and is operable to adjust a spinal fixation element in a first
direction upon pivoting relative to the first arm. The second adjustment
mechanism is coupled to the bone anchor grasping mechanism or the first
adjustment mechanism and is movable relative to the bone anchor grasping
mechanism to adjust the spinal fixation element in a second direction,
perpendicular to the first direction, relative to the bone anchor.