An intervertebral fusion cage (1) produced from a single piece of elastically deformable material and et comprising peripheral walls (2, 3, 4, 62) delimiting, on the inside, at least one inner space for receiving a bone substitute (6), said peripheral walls having: -upper edges together forming an upper plate (71) that is open on the inner space and intended to come into contact with an upper vertebra； -lower edges together forming a lower plate (72) that is open on the inner space and intended to come into contact with a lower vertebra； in which at least one of the peripheral walls forms a wall (62) that is movable by elastic deformation between a so-called insertion position and a so-called anchoring position, the or each movable wall delimiting an inner space of which the volume reduces when said movable wall passes from the insertion position to the anchoring position in order to compress the bone substitute when the latter is present in said inner space. The present invention can be applied to the field of fusing adjacent vertebrae for orthopaedic surgery operations of the spinal column.
