Customized Vacuum Bells for Pectus Excavatum Treatment: A Novel Design Approach

Pectus Excavatum is the most common form of thoracic deformity, characterized by the depression of the anterior chest wall. The most widely used non-surgical treatment involves the daily application of the Vacuum Bell, an external medical device that uses negative pressure to lift the sternum outwards. Nevertheless, the Vacuum Bell is only available in four sizes, making it difficult to apply to all possible cases of deformation. In addition, the variability of the surface to be treated and prolonged use can make the application uncomfortable, leading to decreased compliance and treatment discontinuation, thus compromising its effectiveness. In this context, the study was conducted with the aim of producing customized Vacuum Bell models. Starting with the 3D scanner acquisition of the patient, it was possible to reconstruct the three-dimensional model of the chest. Therefore, a specifically implemented MATLAB script enabled the identification of the surface to be treated and the semi-automatically drawing of the 3D curve outlying the deformation. Using this curve, via CAD software, it was then possible to proceed with the modelling of customized Vacuum Bells, whose profile adapts to the specific conformation of the patient’s chest. Finally, a Vacuum Bell prototype was realized using additive manufacturing techniques.