US Patent 8940049 Expandable intervertebral cage

An expandable intervertebral cage adapted to be implanted into an intervertebral disc space in a patient's body, the expandable intervertebral cage including first and second base plates having outer surfaces configured to interface with vertebra in the intervertebral disc space, a first, second and third arm assembly hingedly connected to first and second base plates, and first and second actuation members, wherein rotation of the first actuation member pulls the second arm assembly towards the first arm assembly and rotation of the second actuation member pulls the third arm assembly towards the second arm assembly, the first actuation member and the second actuation member capable of being actuated independently of each other.