The "fixateur interne" is a new device for posterior spine surgery. It consists of long Schanz screws which are inserted from a posterior approach through the pedicles into the vertebral bodies, and of connecting threaded longitudinal rods, carrying mobile clamps which can be fixed in every position by nuts. The long leverarms of the Schanz screws facilitate manual reduction. They are removed at the end of operation. As the device is stable against flexion and rotation by itself, it does not act on the four-point bending principle. Thus, the fixation can be restricted to the immediately adjacent vertebrae of a lesion, leaving the rest of the spine mobile. In fracture treatment instrumentation is combined with a direct repair of the anterior loss of bone stock by a transpedicular bone grafting procedure from the same dorsal approach. This report presents and discusses 183 instrumentations in fresh fractures, posttraumatic deformities, degenerative diseases, tumors, and severe spondylolistheses. The main advantage is the short fixation area and the ease of after treatment.