In trials with surgical intervention arms, there can be a risk of selection bias toward patients who have already exhausted other available approaches and/or are seeking a surgical intervention. It is also uncertain which primary care patients are most likely to benefit from surgical treatments, and what patient characteristics may in particular affect treatment outcomes. To minimize the potential selection bias and the threats to external validity (i.e., generalizability), PCORI suggests (if appropriate for the proposed study) that all participants be required to complete a baseline period specified by the investigative team featuring conservative standard care, which may include pain medications, activity modifications, exercise, or other approaches.
The contents of the standard care should be known and documented, but it need not be uniform or dictated by a rigid study protocol. Standard care for nonspecific chronic low back pain may vary by region, provider, etc.
In contrast, the comparator arm of the randomized study should feature an “optimized” multidisciplinary intervention, in order to maintain clinical equipoise with the surgical arm. This specialty multi-component intervention should include clinical components that are justified on the basis of convincing evidence regarding their efficacy for chronic nonspecific low back pain. In other words, the nonsurgical comparator arm should represent the “best alternative” to surgery, and its components should have evidence of efficacy when used as part of a multidisciplinary approach to clinical management.