An expandable intervertebral cage , comprising: a housing having: an upper housing portion having an upper plate and upper sidewalls that extend out from the upper plate, wherein the upper plate defines an upper bearing surface configured for placement against an endplate of a first vertebral body; and a lower housing portion having a lower plate and lower sidewalls that extend out from the lower plate, wherein the lower plate defines a lower bearing surface configured for placement against an endplate of a second vertebral body, wherein the upper and lower sidewalls are configured to slide along each other; and an expansion and angular adjustment mechanism disposed between the upper and lower plates, and configured to effect height and angular adjustment of the intervertebral cage, the expansion and angular adjustment mechanism comprising: 1) a leading wedge and a trailing wedge located at opposite ends of the housing, each wedge having upper and lower engagement surfaces configured engage respective engagement surfaces of the upper and lower sidewalls , and 2) a driver component connecting the wedges together and configured to move the wedges toward each other upon actuation of the driver component , thereby causing the engagement surfaces of the wedges to bear against the engagement surfaces of the sidewalls, thereby moving the upper and lower bearing surfaces away from each other; wherein the driver component is further configured to move the leading wedge toward the trailing wedge while forces between the trailing wedge and the housing cause the trailing wedge to remain stationary as the leading wedge moves toward the trailing edge, thereby causing the upper plate to angulate relative to the lower plate . an upper housing portion having an upper plate and upper sidewalls that extend out from the upper plate, wherein the upper plate defines an upper bearing surface configured for placement against an endplate of a first vertebral body; and a lower housing portion having a lower plate and lower sidewalls that extend out from the lower plate, wherein the lower plate defines a lower bearing surface configured for placement against an endplate of a second vertebral body, wherein the upper and lower sidewalls are configured to slide along each other; and an expansion and angular adjustment mechanism disposed between the upper and lower plates, and configured to effect height and angular adjustment of the intervertebral cage, the expansion and angular adjustment mechanism comprising: 1) a leading wedge and a trailing wedge located at opposite ends of the housing, each wedge having upper and lower engagement surfaces configured engage respective engagement surfaces of the upper and lower sidewalls , and 2) a driver component connecting the wedges together and configured to move the wedges toward each other upon actuation of the driver component , thereby causing the engagement surfaces of the wedges to bear against the engagement surfaces of the sidewalls, thereby moving the upper and lower bearing surfaces away from each other; wherein the driver component is further configured to move the leading wedge toward the trailing wedge while forces between the trailing wedge and the housing cause the trailing wedge to remain stationary as the leading wedge moves toward the trailing edge, thereby causing the upper plate to angulate relative to the lower plate . <EOS>