A modular implant device and method for dynamic stabilization of a spine segment that can be implanted in a minimally invasive posterior approach. The implant device has superior and inferior body portions configured for engaging two spaced apart spinous processes to limit extension and, optionally, flexion while off-loading a spine segment. The implant device can stabilize a spine segment, re-distribute loads with the spine segment and still allow spine lateral bending and torsion. Implantation of the device is reversible and adjustable post-implantation.