A sacral prosthesis for a partial or complete sacrectomy has a central body with a platform on a superior face thereof; first and second arms extending superiorly and laterally from the central body, with the arms including respective terminal portions for anchoring to a respective ilium. The terminal portions are held spaced from one another and the central body is suspended by the arms such that the platform is disposed inferiorly to the terminal portions at a fixed position relative thereto. The sacral prosthesis supports a spinal column against inferior displacement by supporting a vertebral body with the platform, while advantageously simultaneously preventing relative lateral displacement of the ilia. The sacral prosthesis may advantageously be formed of a radiolucent material.