Computer aided design of scaffolds for bone tissue engineering

Large bone defects resulting from trauma or tumour surgery are still considered a major challenge in clinical practice. Despite high clinical demand, current treatment options have a number of shortcomings. Bone tissue engineering (BTE)-strategies have therefore been extensively investigated in recent years. The invention of additive manufacturing (AM)-techniques two decades ago has had a huge impact on the BTE field ever since then: Via AM a solid three dimensional structure can be formed from a digital 3D model using a layer-by-layer fabrication process. In the beginning, AM was mainly used to build 3D models of bone pathologies (e.g. fractures, bone tumours) to enable haptic assessment before and during surgery for planning and executing the surgical procedure. However, as new techniques and materials have been developed, AM can nowadays be used to manufacture ultrastructured three dimensional scaffolds for BTE applications as well. Providing control over the internal scaffold architecture on micrometer scale as well as over the external macroscopic scaffold shape, AM enables the fabrication of patient-specific and/or custom-made scaffolds individually tailored to exactly match the size and requirements (e.g. mechanical properties) of a bone defect. In the future, new technologies that enable the direct fabrication of scaffolds with a parallel spatially controlled deposition of cells and growth factors will further underpin the clinical application of bone tissue engineering.