Chest wall kinematics in patients with osteogenesis imperfecta (OI)

In Osteogenesis imperfecta (OI), an inherited connective tissue disorder characterized by brittle bones and significant chest wall (CW) deformities, pulmonary complications are the principal causes of death.In order to study how OI alters chest wall function, we studied 7 patients with severe form type III (OI3), 15 with moderate form type IV (OI4) and 26 healthy subjects (CTR). Breathing pattern, regional CW volume changes and thoracoabdominal asynchronies at rest in seated and supine position were measured by opto-electronic plethysmography. Rib cage deformities was assessed from OEP markers by computing the angle of the sternum (α) on the transversal plane.In both positions, minute ventilation was lower in OI than CTR because of lower tidal volume (p In conclusion, OI3 is characterized by rib cage deformities (pectus carinatum) which alters CW function during breathing.The reduced or paradoxical rib cage motion during inspiration is compensated by an increased action of the diaphragm at rest, associated with large thoracoabdominal asynchrony.