An intervertebral fusion cage for the fusion of two vertebral bodies of the vertebral column comprises a first portion and a second portion opposite the first, both having a planar conformation axially elongated along a central axis. The first and the second portion have respective contact surfaces for receiving, in abutment, a respective vertebral body. The cage can also comprise a gripping area for connection with a positioning device. The first and the second portion are hinged to each other along a hinge axis so as to be able to rotate relatively in relation to each other with a continuous movement.