Advanced 3D Printing of Patient-Specific Human Heart for Improved Surgical Planning

Pre-operative planning in surgery has become crucial, particularly in unusual cases. Modern advancements in 3D medical imaging technologies, such as computed tomography, magnetic resonance, and physical atlases, have revolutionized the preparation process. Additive manufacturing and 3D printing have enabled the creation of patient-specific physical models using medical images. These models have benefited cardiovascular surgery by providing a 3D reconstruction that allows surgeons to explore intricate details that are typically inaccessible. Resin-based polymers are designed to replicate anatomical structures' mechanical properties closely. In order to enhance surgical planning and achieve a more realistic physical model, the mechanical behavior of 3D-printed heart was compared to that of real heart tissue properties in the first-ever attempt to quantify this relationship. A literature review was conducted to obtain a general characterization of the myocardium, focusing on previous studies conducted on animal hearts. Although there was inconsistency in testing methods and sample dimensions, the evaluation metric chosen was the stress at 15% strain. The reviewed studies concurred on cardiac tissue's non-linear anisotropic viscoelastic nature, with reduced responsiveness in the cross-fiber direction compared to the main fiber direction. Synthetic materials used in the 3D printed models are closely aligned with the real specimens regarding the selected metric; however, further investigation into the biaxial properties is needed in addition to functional characterization, such as the shear stress during the cutting procedure.