Spinal stabilization systems are disclosed having spanning portions extending between and securable to pedicle screw assemblies, the spanning portions have stiffness characteristics that may be variable or selectively adjustable, and/or have non-linear behavior with respect to force versus distortion....http://www.google.de/patents/US20090105760?utm_source=gb-gplus-sharePatent US20090105760 - SYSTEMS AND METHODS FOR SPINAL STABILIZATION
