Background and Objectives: Using 3D printed models in orthopaedics and traumatology contributes to a better understanding of injury patterns regarding surgical approaches, reduction techniques, and fracture fixation methods. The aim of this study is to evaluate the effectiveness of a novel technique implementing 3D printed models to facilitate the optimal preoperative planning of the surgical treatment of complex acetabular fractures. Materials and Methods: Patients with complex acetabular fractures were assigned to two groups: (1) conventional group (n = 12) and (2) 3D printed group (n = 10). Both groups included participants with either a posterior column plus posterior wall fracture, a transverse plus posterior wall fracture, or a both-column acetabular fracture. Datasets from CT scanning were segmented and converted to STL format, with separated bones and fragments for 3D printing in different colors. Comparison between the two groups was performed in terms of quality of fracture reduction (good: equal to, or less than 2 mm displacement, and fair: larger than 2 mm displacement), functional assessment, operative time, blood loss, and number of intraoperative x-rays. Results: A significant decrease in operative time, blood loss, and number of intraoperative x-rays was registered in the 3D printed group versus the conventional one (p < 0.01), with 80% of the patients in the former having good fracture reduction and 20% having fair reduction. In contrast, 50% of the patients in the conventional group had good reduction and 50% had fair reduction. The functional score at 18-month follow-up was better for patients in the 3D printed group. Conclusions: The 3D printing technique can be considered a highly efficient and patient-specific approach for management of complex acetabular fractures, helping to restore patient′s individual anatomy after surgery.

The vomeronasal organ (VNO) is a structure located in the anteroinferior portion of the nasal septum and is part of the accessory olfactory system. The VNO, together with its associated structures, has been shown to play a role in the formation of social and sexual behavior in animals, thanks to its pheromone receptor cells and the stimulating effect on the secretion of gonadotropin-releasing hormone. The VNO was first described as a structure by the Dutch botanist and anatomist Frederik Ruysch in 1703 while dissecting a young male cadaver. This finding, however, is widely contradicted due to no elaborate descriptions being made by the Ruysch. The description of the VNO is more widely attributed to the Danish surgeon Ludwig Jacobson, with whom the VNO has been synonymized, as in 1803 he described the structure in a variety of mammals. Whilst Jacobson extensively studied prior reports of the VNO, he publicly denied its existence in humans. Following these discoveries and some contradictory statements in 1891, M. Potiquet published one of the more influential reviews on the topic. To this day, despite the first report of the organ's existence being made in a human and many articles stating its presence and supporting its function, the presence of a VNO in humans is still widely debated upon.

In regenerative medicine, an engineered tissue is a composition of a sample of cells cultured on a spatially controlled medical device, called a biological scaffold (or just a bioscaffold). These devices are made of tissue-equivalent materials and represent the biological, mechanical, and spatial conditions in a specific type of human or animal tissue, becoming a possible way to replace damaged structures and develop artificial tissues or organs. Scaffolds with narrowly controlled characteristics—biological, mechanical and spatial properties—are vital for experiments mimicking in vivo conditions and in tissue regeneration scenarios. The aim of this narrative review is to identify and discuss the most important properties of these artificial constructs and the ways to achieve them via 3D printing-based technologies. Properties that can direct the development and differentiation of the cultured cells in a specific direction and ensure their biocompatibility and bioresorption, mechanical properties, spatial architecture, and porosity are discussed. The most common considerations in terms of the role of material selection, additives, and signal molecules and the appropriate spatially controlled manufacturing technologies for their assembly are covered, as are the radiological, biomechanical, and histological methods for their analysis. Finally, this paper highlights the challenges to the achievement of optimal scaffolds through additive manufacturing and gives suggestions for further research and development in this field.

Nanosilicate-polysaccharide composite hydrogels are a well-studied class of materials in regenerative medicine that combine good 3D printability, staining, and biological properties, making them an excellent candidate material for complex bone scaffolds. The aim of this study was to develop a hydrogel suitable for 3D printing that has biological and radiological properties similar to those of the natural bone and to develop protocols for their histological and radiological analysis. We synthesized a hydrogel based on alginate, methylcellulose, and laponite, then 3D printed it into a series of complex bioscaffolds. The scaffolds were scanned with CT and CBCT scanners and exported as DICOM datasets, then cut into histological slides and stained using standard histological protocols. From the DICOM datasets, the average value of the voxels in Hounsfield Units (HU) was calculated and compared with natural trabecular bone. In the histological sections, we tested the effect of standard histological stains on the hydrogel matrix in the context of future cytological and histological analysis. The results confirmed that an alginate/methylcellulose/laponite-based composite hydrogel can be used for 3D printing of complex high fidelity three-dimensional scaffolds. This opens an avenue for the development of dynamic biological physical phantoms for bone tissue engineering and the development of new CT-based imaging algorithms for the needs of radiology and radiation therapy.

Complex multifragmentary fractures of the pelvis and lower limb are a major challenge for operative orthopaedic surgery. The successful metallic osteosynthesis of the fractures requires an extensive planning process, which can be dramatically improved with the 3D printed anatomical models – replicas of the bones with high fidelity generated from CT and MRI imaging studies. The models represent the spatial properties of the skeleton with a dimensional error of approximately 8 μm/mm. They can be manufactured easily and with high reproducibility with commercial or open-access software and FDM 3D printing. Orthopaedic surgeons use the preoperative models as a highly accurate physical model of complex fractures and allow them to choose and prepare the optimal operation window, surgical tools, metallic implants, and as a template for recontouring (pre-bending) of fixation plates, which will be used during the surgery. The approach provides a new level of personalisation in operative orthopaedic surgery and significantly reduces the duration of the operation, the amount of blood loss and the intraoperative X-rays. The proper anatomical repositioning of the fracture is achieved at a higher rate in the surgeries, which are planned with 3D-printed anatomical models. The planning of surgical operations with 3D-printed models increases the overall effectiveness of the surgery, reduces the rate of post-surgical complications, and allows for a patient-specific approach.The paper will describe the methods for manufacturing accurate 3D-printed anatomical models representing complex fractures and their application for preoperative planning of orthopaedic operation.The anatomical 3D models were generated from CT datasets with open-access medical informatics software (3D Slicer) and 3D printed on an FDM 3D printer with minimal thermal deformation (Polylactate, PLA). The finished models were used for preoperative planning of complex orthopaedic operations, including high-energy multifragmentary hip, knee and ankle fractures. The preoperative planning included selecting surgical access, preparing tools and implants, and contouring (pre-bending) metal plates for metallic osteosynthesis. Several parameters, such as operation time, blood loss, intraoperative X-rays, and the achievement of anatomical reduction of the fractures, were observed in order to measure the quality of the operations.Accurate anthropomorphic 3D models representing the spatial properties of the bones can be generated from tomographic imaging studies easily and accurately, even with open-source software. They can be utilised as a tool for preoperatively planning complex orthopaedical operations of the lower limb. Using 3D-printed models allows a patient-specific approach, which leads to good anatomical reduction and favourable functional results in complex surgeries regarding the pelvis, acetabulum, tibial plateau, and calcaneus.The methods described in the paper are routinely used for the preoperative planning of complex orthopaedical operations regarding the lower limb. In the future, they will be combined with the implementation of 3D-printed personalised titanium implants to achieve good anatomical reduction even for the most challenging multigragmental fractures.In the paper, we described the technical aspects and clinical considerations for the preoperative planning of complex orthopaedical operations, which can assist engineers and clinicians alike in implementing the useful method in clinical practice.

Amajor challenge for the Regenerative Medicine is the development of bioengineered scaffolds, which have similar characteristics to the natural tissues in the body. The composite hydrogels, modified with additives as growth factors and high-performance materials, can be processed into complex three-dimensional structures, able to sustain and provide optimal conditions for the reproduction and differentiation of various cell lineages, including Mesenchymal derived lines. The aim of our project is to 3D print a Polysaccharide/nanosilicate hydrogel, supplemented with platelet lysate and FGF-2. The scaffold will be inoculated with bone marrow – derived MSCs, incubated into bioreactor system with cell culturing media and analysed via histological and cytochemistry methods. With this combination of materials and additives, we want to promote osteogenic differentiation of the MSCs, which will open the possibility for the integration of this method in the clinical practice.