Three-dimensional (3D) printing is based on additive technology in which layers of materials are gradually placed to create 3D objects. The world of 3D printing is a rapidly evolving field in the medical industry as well as in most sectors of our lives. In this report we present current technological possibilities for 3D printing in the surgical field. There are different 3D printing modalities and much confusion among clinicians regarding the differences between them. Three-dimensional printing technologies can be classified based on the basic material used: solid, liquid, and powder. We describe the main printing methods from each modality and present their advantages while focusing on their applications in different fields of surgery, starting from 3D printing of models for preoperative planning up to patient-specific implants (PSI). We present the workflow of 3D printing for the different applications and our experience in 3D printing surgical guides as well as PSI. We include examples of 3D planning as well as clinical and radiological imaging of cases. Three-dimensional printing of models for preoperative planning enhances the 3D perception of the planned operation and allows for preadaptation of surgical instruments, thus shortening operation duration and improving precision. Three-dimensional printed PSI allow for accurate reconstruction of anatomic relations as well as efficiently restoring function. The application of PSI is expanding rapidly, and we will see many more innovative treatment modalities in the near future based on this technology.

Bone morphogenetic proteins (BMPs) are probably the most important growth factors in bone formation and healing. However, the utilization of BMPs in clinical applications is mainly limited due to the protein poor solubility at physiological pH, rapid clearance and relatively short biological half-life. Herein, we develop degradable porous silicon (PSi)-based carriers for sustained delivery of BMP-2. Two different loading approaches are examined, physical adsorption and covalent conjugation, and their effect on the protein loading and release rate is thoroughly studied. The entrapment of the protein within the PSi nanostructures preserved its bioactivity for inducing osteogenic differentiation of rabbit bone marrow mesenchymal stems cells (BM-MSCs). BM-MSCs cultured with the BMP-2 loaded PSi carriers exhibit a relatively high alkaline phosphatase (ALP) activity. We also demonstrate that exposure of MSCs to empty PSi (no protein) carriers generates some extent of differentiation due to the ability of the carrier’s degradation products to induce osteoblast differentiation. Finally, we demonstrate the integration of these promising BMP-2 carriers within a 3D-printed patient-specific implant, constructed of poly(caprolactone) (PCL), as a potential bone graft for critical size bone defects.