346 patients with low-grade spondylolisthesis were randomized to examine the comparative efficacy between two different operations with regard to spinal stabilization, preservation of mobility, improvement in disability, and pain reduction. The two operations compared were Coflex interlaminar stabilization and laminectomy with posterolateral spinal fusion. The results over a two year period indicate that Coflex interlaminar stabilization is a safe and efficacious treatment providing similar results to posterior spinal fusion, with the exception of expected differences in angulation and translation. However, further long term assessments are still required before definitive conclusion can be made.