![]() It has been hypothesized that operational times and complications will be reduced. The reported cases in the literature, together with the huge interest that 3D models have received by the press, have contributed to create high expectations on the impact that such models will have on clinical practice. First-in-man implantation of transcatheter valve and vascular grafts has been successfully supported by preclinical tests performed on patient specific printed models. Realistic models can be valuable in the development of novel approaches and testing new device designs. The use of a 3D printed heart model can help improve communication between clinicians and patients and their families, and medical education with the creation of libraries of models for learning complex anatomy and practicing procedures such as surgical repairs or implantation of devices. 3D printed constructs with different materials: (A) White Nylon (B) Colored Z-Corp (C) Transparent SLA (D) black TangoPlus. The formula for the ‘perfect’ material able to replicate the complex mechanical response of vascular structures is still not available, also taking into consideration that the properties vary from patient to patient, and along the cardiovascular districts, and they are challenging to identify during standard clinical assessment.įigure 4.3. The research of materials with realistic values of flexibility and, at the same time, resistant to physiological loads, has recently led to testing the use of silicone, shape memory polymers, and biofabricated materials. Another commercially available material, Heart Print Flex, was purposely produced and introduced to the market for these specific applications. Research has shown how models of this material printed with varying thickness were suitable to mimic the distensibility of different arteries or to accommodate a self-expandable stent in a model of a patient specific implantation site. One of the first 3D printing compatible flexible materials has been a commercially available compound (TangoPlus FullCure). Mimicking the distensible mechanical properties of the cardiovascular structures with 3D printed models is still challenging because of the inherent differences between the mechanical behavior of polymeric materials and that of human tissues. To plan procedures such as an insertion of a device or practicing surgical cuts and stitches, it is more appropriate to manufacture flexible models that can implement the realistic compliance of blood vessels. To communicate with patients, their parents, and for training of the junior clinical staff, colored models can facilitate the understanding of complex cardiovascular structures. To visually assess the anatomy, relatively inexpensive rigid models can be made of polymers like acrylonitrile butadiene styrene (ABS), polylactic acid (PLA), polyamides (e.g. The criteria of choice of the printing technology have to take into account time and costs of fabrication and, crucially, the intended use of the models. ![]() In the cardiovascular field, the most commonly used technologies are fused deposition modeling, selective laser sintering, sterolitography, and material jetting. In other chapters of this book, the authors have broadly explained the technologies available on the market for medical applications. ![]() The STL format can be transformed into a physical object by means of additive manufacturing. ![]() The Voronoi tessellation-based geometries have been extensively exploited in simulations thanks to the wide availability of Voronoi tessellation tools in 2D (in classical softwares such as MatLab) and in 3D thanks to the available open implementations such as VORO ++ ( Rycroft, 2009 Rycroft, Grest, Landry, & Bazant, 2006).Ĭlaudio Capelli, Silvia Schievano, in 3D Printing in Medicine, 2017 4.3 Patient specific models: 3D Manufacturing These alternative tessellations bear some link to the presence of inclusions (sphere/circles in this case), suggesting that the generation of inclusion-based geometries can be further exploited for tessellating space as will be explained in Sections 3 and 4. Laguerre tessellations use a sphere/circle power distance on circle/sphere seeds. The additively weighted Voronoï tessellation can be seen as using an Euclidean distance measure with circle/sphere seeds. For example, the Voronoï tessellation uses points as seeds and the Euclidean distance as distance measure. One sub-domain is generated for each seed and cells are exactly adjacent to each other as every point in the domain should have a nearest seed. Massart, in Advances in Applied Mechanics, 2021 2.2.1 Principles of classical tessellation methodsĬlassical tessellations techniques produce tilings by gathering in each tessellation cell points closer to a seed according to a certain distance measure.
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