Unraveling the Mechanisms of Manual Therapy: Modeling an Approach

TLDR

Manual therapy is widely used, yet systematic reviews show limited effectiveness, likely due to small effect sizes and a lack of understanding of the complex, patient‑, provider‑, and environment‑dependent mechanisms that underlie pain inhibition. This commentary proposes a mechanistic model to guide study design and interpretation, aiming to identify patients who will benefit from manual therapy. The model posits that manual therapy’s mechanical force triggers systemic neurophysiological responses that inhibit pain. Published in J Orthop Sports Phys Ther 2018;48(1):8‑18, doi:10.2519/jospt.2018.7476.

Abstract

Synopsis Manual therapy interventions are popular among individual health care providers and their patients; however, systematic reviews do not strongly support their effectiveness. Small treatment effect sizes of manual therapy interventions may result from a "one-size-fits-all" approach to treatment. Mechanistic-based treatment approaches to manual therapy offer an intriguing alternative for identifying patients likely to respond to manual therapy. However, the current lack of knowledge of the mechanisms through which manual therapy interventions inhibit pain limits such an approach. The nature of manual therapy interventions further confounds such an approach, as the related mechanisms are likely a complex interaction of factors related to the patient, the provider, and the environment in which the intervention occurs. Therefore, a model to guide both study design and the interpretation of findings is necessary. We have previously proposed a model suggesting that the mechanical force from a manual therapy intervention results in systemic neurophysiological responses leading to pain inhibition. In this clinical commentary, we provide a narrative appraisal of the model and recommendations to advance the study of manual therapy mechanisms. J Orthop Sports Phys Ther 2018;48(1):8-18. doi:10.2519/jospt.2018.7476.