Expandable, angularly adjustable intervertebral cages

The embodiments provide various interbody fusion spacers, or cages, for insertion between adjacent vertebrae. These intervertebral cages can restore and maintain intervertebral height of the spinal segment to be treated, and stabilize the spine by restoring sagittal balance and alignment. The cages may have a first, insertion configuration characterized by a reduced size at each of their insertion ends to facilitate insertion through a narrow access passage and into the intervertebral space. The cages may be expanded to a second, expanded size once implanted. In their second configuration, the cages are able to maintain the proper disc height and stabilize the spine by restoring sagittal balance and alignment. The intervertebral cages are configured to be able to adjust the angle of lordosis, and can accommodate larger lodortic angles in their second, expanded configuration. Further, these cages may promote fusion to further enhance spine stability by immobilizing the adjacent vertebral bodies.