Disc Height and Sagittal Alignment in Operated and Non-Operated Levels in the Lumbar Spine at Long-Term Follow-Up: A Case-Control Study

PURPOSE To compare lumbar disc degeneration at 9-year follow-up in patients with chronic low back pain who had instrumented lumbar fusion or no fusion. MATERIAL AND METHODOLOGY The main outcomes were disc height and sagittal alignment measured by Distortion Compensated Roentgen Analysis (DCRA). Secondary outcome included the Oswestry Disability Index and VAS back pain. RESULTS Forty-eight patients with baseline and 9-year radiographs from L2- S1 were included. Twenty-three had lumbar fusion and 25 had no fusion. Disc height was reduced at all levels independent of fusion. No difference in disc height and sagittal alignment was observed between patients fused and not fused. There were weak correlations, ranging from 0.04 to 0.36, between clinical and radiological parameters. CONCLUSION Lumbar disc degeneration increased at all measured levels independent of fusion and correlated poorly with clinical outcome.