A spinal cage includes first and second spinal attachment members attachable to vertebrae, the first and second spinal attachment members articulating with one another by means of an articulation joint, and a wedge element arranged for wedging between the first and second spinal attachment members. An actuator is linked to the wedge element for moving the wedge element axially with respect to the first and second spinal attachment members. The actuator includes a threaded member adjacent the wedge element and a biasing device positioned between at least one of the first and second spinal attachment members and the wedge element. Upon turning of the threaded member, the wedge element is advanced with respect to the articulation joint so that the first and second spinal attachment members are tilted or parallel to each other. The biasing device applies a biasing force on the wedge element to move the wedge element axially.