At the time of SPORT, the principal clinical question was whether surgical treatment options were superior to nonsurgical treatment for patients with low back pain related to lumbar spinal disorders, including disc herniation, spinal stenosis, and degenerative spondylolisthesis. Prior to SPORT, the Maine Lumbar Spine Study, which enrolled 148 patients, was the largest study comparing the effectiveness of alternative treatments for spinal stenosis. Using a prospective-cohort design to compare surgical and nonsurgical approaches, this study found that patients who underwent surgery had better outcomes at three months, and these results held over the first year of follow-up (Atlas, Deyo, et al., 1996) before declining slightly over the next four years (Atlas, Keller, et al., 2000). While the surgical-intervention group appeared to have better outcomes in this study, nearly 25 percent of those undergoing surgery had no benefit, depending on the particular outcome (Atlas, Deyo, et al., 1996).
A 2005 Cochrane review summarizing the evidence prior to 2000 suggested that the relative efficacy of surgery was not established, because existing trials were small and enrolled patients both with and without degenerative spondylolisthesis (Gibson and Waddell, 2005). A large, randomized CER trial was considered necessary to provide stronger evidence on the benefits of surgical treatment for spinal stenosis among patients who did not have degenerative spondylolisthesis.