Interventional procedures and physical therapies.

Placebo effects are inherent in all healthcare encounters and are underpinned by the therapeutic context. Every therapeutic context is rich in its ability to initiate and maintain placebo mechanisms, with the healthcare provider clinician interaction a crucial cornerstone. When one adds the powerful elements of touch, such as in physical therapies, and the technology and ritual associated with percutaneous or surgical interventions, robust placebo effects can be generated. However, the very elements of the therapeutic context and ritual that come with touch and intervention provide challenges. For those who design clinical trials, the ability to have an adequate placebo control maintaining robust blinding remains problematic as is the broader role of using placebo groups over other forms of controls. Nevertheless, researchers, clinicians, and patients need to better understand the relative contribution of placebo mechanisms to treatment effects, particularly for invasive and potentially costly treatments. On the other hand, the use of placebo controls has allowed us to better appreciate placebo effects in clinical populations and this remains an important aspect in improving the harnessing of placebo mechanisms to improve clinical care. This chapter will address issues around placebos in physical therapy and interventional trials through the lens of improving clinical trial design but also the interpretation of how placebo effects operate across physical and interventional treatments so they can be better understood and augmented in the future.