Radcliff K, et al. - In this randomized clinical trial, the researchers assessed the incidence and risk factors for secondary surgery in cases treated with total disk replacement (TDR) or circumferential fusion at 2 contiguous levels of the lumbar spine. Compared to the fusion cases, there were significantly fewer reoperations in TDR patients. In the fusion cohort, most of the secondary surgeries were instrumentation removal. No significant difference in reoperations between TDR and fusion was noted, discounting the instrumentation removals. Experts found that lumbar TDR was noninferior to fusion.