The application relates to an intervertebral fusion implant for fusing two adjacent vertebrae, comprising an adjustable support member (2), the bottom and top surfaces (23, 34) of which are designed to come to rest on end plates of the adjacent vertebrae. A side arm (3) which can be laterally swiveled about a joint (30) has a planar bottom (34) and a planar top (33). An actuation device (4) is provided for swiveling the side arm (3) into a position in which the side arm is spread apart from the support member (2) (fig. 2b； operational position). As a result, the implant is particularly small and can, after being implanted at the target location, be actuated in such a way that it expands and consequently provides a larger support surface in the intervertebral space. Minimally invasive surgery can thus be used to heal even relatively large-area defects.
