Generating New Evidence for Lumbar Spondylolisthesis: Registries and Randomized Controlled Trials.

Randomized prospective studies demonstrate clear benefits for operative versus nonoperative management of symptomatic lumbar spondylolisthesis, but, despite the current randomized controlled trial (RCT) evidence, there remains no universally accepted surgical treatment. The challenge inherent to an RCT is the impact nonadherence presents to evaluating a treatment effect in spinal procedures. Prospective registry data reflect the current practice of spine surgery. While not randomized, the registry data are continuous and available potentially in orders of magnitude greater than RCT.