A new perspective for Somatic Dysfunction in Osteopathy: the Variability Model

Introduction: Osteopathy uses manipulative techniques to support physiological function and adaptation. These conditions are modified by the presence of Somatic Dysfunction (SD), an altered function of the components of the body's framework system. Despite SD's widespread use in clinical practice and education, research has previously shown poor results in terms of reliability and validity. In this theoretical article, the authors' proposal is to argue for a new clinical perspective for SD, which suggests a different palpatory assessment of its clinical signs: the "Variability Model". Methods: A double simultaneous literature search was performed between January and March 2019 in Medline's electronic database. The first one critically analysed the clinical signs most used to detect SD. The second one informed authors' hypothesis related to movement variability assessment in the Neutral Zone (NZ). Discussion: The Variability Model explains how the assessment of the range of motion in the NZ is essential to detect SD, its motion asymmetry and its relative restriction. The Variability Model explains SD semeiotics which could be related to "body adaptability", thus having implications with the concept of health. Finally, this paradigm aims to establish new developments in research, especially regarding SD reliability and clinical relevance. Conclusions: Movement variability allows to interpret SD clinical signs as an attempt by the body to maintain a healthy condition. This paradigm should be included in the future context of osteopathy which could better explain SD's pathophysiological mechanism, without ignoring the accuracy of its physical examination. (C) 2020 Elsevier Ltd. All rights reserved.