Reverse shoulder arthroplasty: methodology improvement through personalized modelling techniques and FDM technology

Abstract

[EN] Reverse shoulder arthroplasty (RSA) is a surgical technique that relieves pain and functional incapacity in certain shoulder pathologies. Adequate sizing and positioning parameters are very sensitive to each individual patient's shoulder features, such as: degenerative stage and glenoid morphology among others. The interplay of different shoulder features is often nuanced, nontrivial, and highly nonlinear. Therefore, general guidelines can often fall short at delivering the best possible clinical outcomes. To overcome this, a new trend uses imaging techniques to manufacture bespoke mechanical guiding tools customized to each patient's shoulder features. The application of FDM technologies allows doctors to obtain physical models of the patient's bone geometry in anticipation of surgery and, consequently, the manufacturing of a patient-specific guide to be used to guarantee the correct position of the glenoid base plate during surgery. This paper focuses on the design and further manufacturing process developing a protocol that controls and minimizes the manufacturing deviations, in order to get to the optimal product design using the patient's Computed Tomography (CT) information. The modelling and parametrization of the customized guide is based on the study and optimization of the bone reconstruction as well as the variables of the manufacturing process. In this research both the CAD information analysis and the FDM process are focused on the application of new design techniques and the optimization of bones geometry analysis in order to obtain a specific surgery guiding tool to be manufactured by FDM with limited deviations.