Methods and apparatus are disclosed for performing spinal reconstructive surgery, including measuring spinal length in the Y-axis at the middle column, measuring intervertebral spacing in the Y-axis at the middle column, measuring intervertebral tension applied to the posterior longitudinal ligament, establishing the height of intervertebral spacers along the Y-axis at the middle column based on one or more of such measurements, measuring intervertebral rotation around the Y-axis, and measuring flexion-extension or anterior-posterior rotation around the X-axis.
