3D printing of costal cartilage models with fine fidelity and biomimetic mechanical performance for ear reconstruction simulation

Patient-based training is difficult in ear reconstruction surgery; therefore, costal cartilage models are required for surgical education and pre-operative simulation. Here, we aimed to fabricate personalized models with mechanical and structural similarity to native costal cartilage to simulate ear reconstruction in microtia patients. To achieve this, the stiffness, hardness, and suture retention ability of both native costal cartilage and printed silicone were experimentally examined in vitro. Rheological tests and three-dimensional (3D) comparison methods were used to evaluate the printing ability and outcomes. The printed silicone models were used by residents to practice ear framework handcrafting during ear reconstruction surgery, and the residents' learning curves were analyzed. In addition, the models were used for pre-operative simulation to study and optimize the surgical plan. The results showed that the consistency of mechanical properties within cartilage and silicone was verified. Printable silicone had good shear-thinning properties, and the printed structures had almost perfect printing fidelity. Residents who used printed silicone models enjoyed great progress and confidence after training. The pre-operative simulation optimized the carving scheme, reduced trauma in the operative site, and avoided wasting necessary cartilage tissue. Overall, fine-fidelity models created in this study were intended for surgical education and pre-operative simulation by applying 3D-printable (3DP) silicone, facilitating the optimization of surgical plans. Surgeons were satisfied with this kind of model and recognized the efficacy and great application value of 3D-printed silicone models for clinical practice.