Methods and apparatus for controlling flexion in a spinal segment of a patient include performing a spinal fusion procedure on a pair of adjacent vertebrae in the spinal segment and implanting a constraint device into the patient. Adjusting length or tension in the constraint device allows the constraint device to provide a force a force resistant to flexion of the spinal segment undergoing fusion. The constraint device also modulates loads borne by the spinal segment undergoing fusion or tissue adjacent thereto.
