The true physiological effects of manual therapy, despite being shown to be effective in literature in the reduction of pain, continues to be widely unknown. It is thought that many manual therapy techniques work through a combination of both neurophysiological as well as biomechanical mechanisms. Despite literature showing the effects of manual therapy to be positive, many aspects of the biomechanical model of assessment and treatment, which many therapists use in assessing a joints “hypomobility” as well as “alignment” , has been found to be unreliable and found to not have an effect on clinic outcomes. In addition, the neurophysiological mechanisms are poorly understood. So what is really happening to our patients when we apply manual therapy for the reduction in pain?
Bialosky et al attributes interventions such as manual therapy as a “structured experience” vs. an isolated intervention. They believe that the technique, provider, participant, environment and interactions between those factors will effect patient outcomes. Mixed into these variables is placebo, which cannot be ignored when measuring a patients outcome.
Placebo must be thought of as a mechanism which can account for some of the effects of what we do. It can have physiological and psychological effects on pain and is a relevant contributor in manual therapies reduction of pain. The term has generated a negative conotation due to its frequent use as a control in many scientific studies but in reality a placebo response is a real response.
The authors of this article recommended that therapists take steps in maximizing placebo responses within ethical limitations. They believe by minimizing negative moods, maximizing realistic expectations and drawing on patients preferences and past experiences in the use of manual therapy, the patient will have a better outcome.
Bialosky JE, Bishop MD, George SZ, et al. Placebo response to manual therapy: something out of nothing? J of Man and Manip Ther 2011; 19: 11-19.
Vase K, Peterson GL, Riley JL 3rd, Price DD. Factors contributing to large analgesic effects in placebo mechanism studies conducted between 2002 and 2007. Pain 2009; 145: 36-44.