The invention relates to an implant for the transforaminal intracorporeal fusion of lumbar vertebral column segments. At least some sections of the surface areas that are in direct contact with the spinal column are provided with an anti-dislocation mechanism (1) while an attachment part (4) for a positioning instrument (10) is provided in or on the implant and holes (6) or hollow spaces are disposed in the implant for filling purposes. According to one embodiment of the invention, the attachment part is configured as a revolute joint. In a further embodiment, the implant member has the shape of a sickle, the curvature of which is oriented ventrally and the interior of which is oriented dorsally. The attachment part is located at one end of the sickle while the opposite end of the sickle has a beak-type, tapering shape (5). At least one filling hole is provided between the sickle walls.