Various methods, devices, and systems are disclosed that facilitate easier and more compact implantation of osteosynthesis devices. In some embodiments, implants are screwed into two vertebrae and a plate is used to hold and displace the spine. In some plate embodiments, at least one longitudinally elongated opening is disposed at one end of the plate and partially opening onto an edge of the plate. In some plate embodiments, at least one longitudinally elongated opening is disposed at one end of the plate having a portion sufficiently large to be inserted without disassembly in the fixation means of an implant already screwed into the spine when the fixation means are already assembled.
