A novel design of thoracic implant with dynamic capacity has already been reported, with promising short-term outcomes. This has led to case reports on reconstructions with these prostheses, particularly for large anterior resections. The evolution of additive manufacturing has enabled the production of 3D custom-made thoracic implants. Early rigid implants have provided the stabilization of the ribcage however, those have been associated with breathing restrictions. Large thoracic defects need to be reconstructed to restore inner organs protection and normal ventilation. (1965), the volume displacement of the rib cage, denoted by D V, is related to the change of. Based on the empirical equation presented by Agostoni et al. The applied effective normal force of weakened respiratory muscles, denoted by F, is normalised by the The computational model explained in Section 2, provides an estimate of the rib displacement during respiration which can be related to volume displacement of the thoracic cage using the empirical relationships discussed in Section 3.
The effect of the age-related muscle weakness was investigated by decreasing the value of the intercostal muscles’ force systematically up to 40% (see Section 1). For studying the effect of costal cartilage and synovial joint calcification on the ‘bucket-handle’ movement of the rib, the same intercostals muscle force was exerted to the rib.
RIB CAGE DIAGRAMS TRIAL
The magnitude of this constant distributed force was evaluated by trial and error in order to obtain a defined maximum vertical displacement in the ‘bucket-handle’ movement for a healthy rib. This is based on the fact that intercostal muscles are the most effective muscles in forcing the rib cage to expand transversely. Here without emphasising on the actual muscle force, the transverse movement of the rib was evaluated by applying a constant vertical distributed force along the top boundary line of the rib. The contribution of each of the thoracic muscles to respiration is so complex that despite a few conducted studies, still the nature of forces and moments applied to the rib during an inspiration has not been completely understood (De Troyer et al. The respiratory muscles are divided into two groups: muscles with primary function and muscles with secondary function of respiration. The static load applied to the rib was estimated by considering the effective force exerted by the respiratory muscles. The finite element analyses were performed by considering large deformation and finite strain conditions under static loading. The costotransverse joint was modelled as a roller, as the plane type of synovial joint permits gliding and sliding along the opposed surface of the joint, which is flat or almost flat (Moore 1992). Chen (1978) used the same modelling assumption for studying the response of the chest under impact loading. The synovial joint was modelled as a ball and socket joint as they give the rib the ability to rotate about its axis in the ‘bucket-handle’ movement of the rib. The costotransverse joint of the fifth rib is typically a plane type synovial joint (Moore 1992). The sternocostal joints of the second to seventh ribs are synovial joints, as well as the joints at the head of the ribs to vertebral column.
Furthermore, a typical rib articulates with the vertebral column at two joints: at the joint of the head of the rib and at the costotransverse joint ( Figure 1). The first to seventh ribs articulate with the lateral border of the sternum via their costal cartilages (sternocostal joints). modelling of rib articulations is critical for accurate analysis of the rib movement during respiration.