An intervertebral spacer for therapeutic treatment of a patient includes at least one link sized and dimensioned to fit within an intervertebral space in the patient, and is configured to maintain a separation of two adjacent vertebrae for a period of time. A rigid guiding object, which may be a tool or a successive link, is insertable into the patient, to guide other links into the patient using an MIS approach. A pivot is connected between successive links, or between a guide tool and a link, configured to limit a relative range of angular orientation between the link and the guiding tool, or successive links. Multiple links are so joined to form a chain pushable by the last link, and pullable by the first link, to form a chain which may be formed into a curved configuration corresponding to the patient's intervertebral space.