The effect of pedicle screw/plate fixation on lumbar/lumbosacral autogenous bone graft fusions in patients with degenerative disc disease.

STUDY DESIGN

A prospective, multi-center Investigational Device Exemption Study was carried out in the United States using a pedicle screw and plate system to perform a fusion in patients with degenerative disc disease or spondylolisthesis. The patients' pain function, complications, and fusion status were evaluated and compared with literature controls.

OBJECTIVES

To study the safety and efficacy of the ISF pedicle screw/plate system. This article focuses only on those study patients with degenerative disc disease treated with autogenous bone grafts and compares the results to those of similar patients treated without instrumentation, as reported in the literature.

SUMMARY OF BACKGROUND DATA

Twenty-eight patients were in the subgroup studied--patients with degenerative disc disease who had fusions with autogenous bone graft. This study was conducted at four clinical sites with a 2-year follow-up. Patient follow-up was greater than 95% at all time points.

METHODS

To be considered a patient with degenerative disc disease, radiographs had to demonstrate a collapse of the disc, the presence of bone erosion, or the compression of the vertebrae as the primary spinal abnormality. Spinal fusion must have been the recommended surgical treatment for discogenic pain. The fusion status was evaluated by the operating surgeon and an independent reviewer.

RESULTS

After 2 years, this subset of patients (n = 28) with degenerative disc disease who had lumbar/lumbosacral fusion with autogenous bone graft was found to have a pseudarthrosis rate of 0%. Eight articles in the literature were found to be valid noninstrumented literature controls with which this subgroup could be compared. The average pseudarthrosis rate in the control group was 32%.

CONCLUSIONS

A statistical analysis showed that patients with degenerative disc disease who underwent fusion without pedicle screw instrumentation were over 24 times more likely to have a pseudarthrosis than comparable patients implanted with a pedicle screw/plate system. Regarding the most important goal in performing a spinal fusion--fusion of the spine--the pedicle screw/plate system used in this study was shown to be a safe and efficacious method of facilitating fusion with autogenous bone graft for this patient population.