Ultrasound Evaluation of Changes in Diaphragmatic Motion and Contractility Induced by Osteopathic Manipulative Techniques: a Prospective, Randomized, Double Blinded, Case vs Sham vs Control Clinical Trial.

Introduction The diaphragm is the dome-shaped sheet of muscle and tendon that serves as the main muscle of respiration and plays a vital role in the breathing process. Also known as the thoracic diaphragm, it represents an important anatomical landmark that separates the chest, from the abdomen.

Indeed, the diaphragm muscle extends from the trigeminal system to the pelvic floor, passing from the thoracic diaphragm to the floor of the mouth. Apart of its anatomy and related anatomical connections, the abdominal diaphragm has been proved to develop many other pivotal relationships: neurologic, vascular and lymphatic, fascial connections The complex anatomic and bio-mechanic structure of thoracic diaphragm, as well as its widespread influences and interactions with both contiguous and more distant areas of the human body, provide a robust rationale for an osteopathic and manipulative approach.

Traditional osteopathy, as presented by the Canadian College of Osteopathy, is defined as: "A natural medicine which aims to restore function in the body by treating the causes of pain and imbalance. To achieve this goal the Osteopathic Manual Practitioner relies on the quality and finesse of his/her palpation and works with the position, mobility and quality of the tissues." A wide number of osteopathic techniques focusing on diaphragm have been proposed but, although systematically and efficiently used, there is a general lack of evidences able to clarify how and to which extent osteopathic manipulative treatment (OMT) on diaphragm is effective and determines a modification in muscles contractility and motion as well as an objective determination of the benefit on the patients receiving treatment.

In a recent study da Silva and colleagues compared manometry pressures of the lower esophageal sphincter before and immediately after osteopathic intervention in the diaphragm of subject with gastroesophageal reflux founding a positive increase in the pressures soon after osteopathic treatment ; however, the estimation of the impact of OMT on diaphragmatic activity was indirect and did not provide any information about changes in motility and contractility; in another large double-blinded, randomized, controlled trial, four hundred and six hospitalized subjects with pneumonia were randomized to receive conventional care only, light touch treatment or OMT, including the doming technique of the diaphragm, in adjunction to conventional treatment for pneumonia. Authors found a significantly shorter length of stay in the OMT and light touch groups vs controls but, once again, they were not able to provide any causal relationship between OMT and diaphragmatic activity . Finally, the effect of OMT in COPD patients has been investigated with contrasting results: in a study on 35 subjects OMT protocol consisted of seven standardized osteopathic manipulative techniques including indirect myofascial re-doming of the diaphragm was compared with sham therapy. Interestingly, results suggest an overall worsening of air trapping during the 30 minutes immediately following one multi - technique OMT session relative to the sham group . Under an indirect point of view, this result favors a role of OMT in diaphragm mobility reactivation, since it may be related to a dynamic hyperinflation-like mechanism promoting air trapping. On the other side another study demonstrated an improved lung function in severely obstructed subjects with COPD following OMT. Thanks to the new hand-held ultrasound instruments, the morphology and function of the diaphragm can be assessed in different settings, such as outpatient clinic, pulmonary function test laboratory, hospital department and intensive care unit, and under different conditions. Ultrasonography is the only non-invasive, non-ionizing imaging technique widely available to directly assess diaphragmatic function. Two different sonographic approaches permit the assessment of muscle thickening in the zone of apposition and excursion of the dome of the diaphragm.

This study therefore aims at investigating whether, to which extent, and how, a single session of selected osteopathic diaphragmatic techniques is able to affect muscle motility and thickness, assessed by ultrasounds, in a sample of healthy subjects and to compare results versus a group receiving a sham therapy and another one of non-treated subjects.