This paper reports on 41 patients available for 24 months' follow-up who were entered into a prospective, multi-center study of the safety and efficacy of using the CD Spinal System (Sofamor Danek) containing pedicle screws and rods to treat adult patients with degenerative disc disease. All of these patients were implanted with only the CD Spinal System in an attempt at fusing four levels or less with autogenous bone graft only. At 24 months the results were compared to literature controls in regard to fusion, pain, function, neurological status, and complications. For function and neurological status, the CD Spinal System results were found to be statistically equal to and for fusion, pain, and complications, found to be statistically better than the noninstrumented literature controls with the same disease condition and demographics.