A device for insertion into a spinal (intervertebral or intravertebral) space is expandable from a first circumference to a second circumference through axial compression of segments of the device, particularly once the device has been properly situated within a vertebral space. The interbody/intravertebral...http://www.google.ca/patents/US7731751?utm_source=gb-gplus-sharePatent US7731751 - Expandable spinal devices and method of insertion
