60 patients scheduled for anterior-posterior spondylodesis for treatment of degeneration of L4/L5 or L5/S1 were randomly divided to receive a single-level fusion or a single-level fusion with dynamic fixation of the degenerated segment adjacent to the one being fused. Fusions and degenerative progression measured by a radiologist, functional outcomes and pain were assessed preoperatively and at 12 and 60 months postoperatively. There was no difference detected between the two groups when examining functional outcomes, pain or overall radiological results; however, the dynamic fixation resulted in more implant failures.