A Simple Interactive Tool for the CAD Modelling of Surgical Guides for Autologous Ear Reconstruction

The huge possibilities generated by the introduction of rapid prototyping techniques in the medical field has paved the way for collaborations between physicians and engineers to produce personalized medical devices, tailored to the specific anatomy of the patient. Specifically, in the field of autologous auricular reconstruction, i.e. the reconstruction of the external ear using the patient's costal cartilage, the authors worked towards the development of new patient-specific intraoperative devices, to support the surgeon during the procedure. The surgical guide design was then supported by the development of automated techniques for their modelling. In this work, a new hybrid technique for the CAD modelling of surgical guides is proposed. The idea is not to totally eliminate the intervention of the physician in defining the shape of the surgical guides, but rather to simplify their interaction with design tools. The proposed method is based on the straightforward adaption of a two-dimensional template developed by evaluating various auricular biometric parameters to approximate ear structure. The template is coupled to a parametric automatic procedure that generates the surgical guides' CAD model. The template was created outside of commercial CAD modeling software packages to make the procedure more accessible, and it is managed using a well-designed graphical user interface. With specialized questionnaires to evaluate the surgeon's satisfaction, the interface was put to the test, and the results were positive.