Abstract: A spinal fixation device including two plates, a connector element for either coupling the plates in a fixed manner between the L5 vertebrae and the sacrum, and an anchor element to anchor the spinal fixation device to the sacrum. Each plate is preferably equipped with integral spikes on the inwardly facing surfaces for pressing into the spinal processes and thereby augmenting the purchase between the plates and the spinous processes. Each plate contains a central aperture through which the connector element passes in order to couple the plates together.