Disclosed herein are expanding spinal fusion cage embodiments including an expandable cage assembly configured to expand from a collapsed state to an expanded state in an intervertebral space when inflated with a material. The assembly can include an inflatable section defining an interior volume configured to receive the material and expand the interior volume in response to a pressure from the received material to cause the expandable cage assembly to transition from the collapsed state to the expanded state, and a stabilization section configured to restrain the inflatable section during inflation.