Most experts believe that SPORT had little or no impact on the use of surgery for the three spinal disorders studied. Notably, the publication of the SPORT results included both the intention-to-treat results and the post-hoc observational-cohort study results, potentially adding an element of confusion to their interpretation. The majority of our discussants felt that the intention-to-treat analysis was “uninformative” because of the very high level of crossover, while the observational-cohort analysis was considered to be of high quality and to have produced useful information. Interpretations of the observational-cohort study results generally divided along specialty lines: spinal surgeons embraced them, while nonsurgical spine physicians were more skeptical. Because the observational-cohort results were broadly consistent with those of two earlier studies—the Maine Lumbar Spinal Study and the Finnish trial by Malmivaara (Malmivaara, Slatis, et al., 2007)—the SPORT findings appear to have reinforced the conventional wisdom that surgical intervention is the preferred strategy for treating spinal stenosis.
Discussions with several orthopedic surgeons indicated that the interpretation of the results was more nuanced than we expected. Several discussants said that the patients participating in the observational study who selected nonsurgical treatment did “fairly well” (despite the fact that those results were not emphasized in the dissemination phase) and that surgical patients did not have sizable improvements in health outcomes. They pointed out that the goal of the trial was not to determine whether surgery “worked,” since prior studies had already provided some evidence, but rather to provide estimates of the magnitude of benefits and harms, which clinicians and patients could then use in making decisions about the value of surgical treatment. This perspective reflects the unique weights that individual physicians and patients may assign to various treatment effects when interpreting CER evidence.