Abstract: This study presents a fully automated pipeline for the morphometric analysis of the dens, based on an enhanced Statistical Shape Model of the C2 vertebra. Developed in MATLAB, the pipeline integrates semantic segmentation directly into the shape model, enabling precise and reproducible identification of anatomical regions without manual intervention. Unlike deep learning approaches, the proposed framework is well-suited to applications involving limited or heterogeneous data. The model was trained on 25 C2 vertebrae from the VerSe dataset and tested on three independent specimens. Evaluation of model compactness, generalization, and specificity confirmed the robustness of the Statistical Model. Morphometric parameters are extracted in reference to a local coordinate system derived from the mean C2 shape, ensuring anatomical consistency across specimens. The morphometric results for the dens fell within the anatomical ranges reported in the literature, supporting the method’s validity. While not intended for clinical use due to dataset limitations, this work lays the foundation for scalable, reproducible, and anatomically informed morphometric analysis of the dens.

Keywords: Automatic Feature Recognition | Biomedical Image Analysis | Statistical Shape Modeling

Abstract: This paper proposes an innovative framework based on artificial intelligence techniques to optimize the reuse of End-of-Life (EoL) ICT components. The system integrates two complementary modules: (1) zero-shot identification and classification of mechanical components from images using Segment Anything Model (SAM) and Contrastive Language-Image Pretraining (CLIP); (2) reuse profitability assessment through a Recovery Profitability Index (RPI) and Transformer models. Experimental results demonstrate an identification accuracy of 78% for the zero-shot module and up to 91% for profitability classification, highlighting the potential of this approach in the context of circular economy and industrial sustainability.

Keywords: Circular Economy | Transformer Models | Zero-Shot Learning | ICT Components Reuse

Abstract: The rapid integration of artificial intelligence (AI) into clinical research is transforming the landscape of biomedical innovation, influencing numerous phases of research, with critical ethical and legal implications. Regulation (EU) 2024/1689, commonly referred to as the AI Act and issued in 2024, introduced a new regulatory framework that classifies AI systems used in clinical settings as ‘high risk’, requiring increased scrutiny by ethics committees and national authorities. This review addresses ethical and regulatory challenges and discusses the application of the AI Act within real-world clinical research. We propose a three-phase lifecycle (training, real-world testing and post-marketing monitoring) to align regulatory burdens with AI maturity. Our recommendations include transparent protocol design with explicit data-use declarations, complementary application of the Medical Device Regulation and the AI Act, with particular attention to the early research phases. This approach provides practical indications for researchers and operational evaluation criteria for ethics committees to ensure patient safety while fostering trustworthy AI deployment in clinical trials.

Keywords: Artificial intelligence | clinical research | ethical principles | ethics committees | European Union regulations

Abstract: This paper introduces a fully automated pipeline for the morphometric analysis of the odontoid process (dens) of the second cervical vertebra, based on an enhanced Statistical Shape Model (eSSM). The proposed framework integrates semantic and geometric information into the statistical model, enabling automatic identification of dens and related anatomical entities, as well as the extraction of morphometric parameters from three-dimensional anatomical models. The pipeline includes automatic alignment of the vertebrae to a standardised Local Coordinate System, semantic segmentation of the dens based on skeleton-line analysis, automatic geometric detection of the inferior surface of the vertebral body, and a dedicated measurement protocol that relies on slicing and convex hull computation. Unlike deep learning approaches, the eSSM framework inherently preserves anatomical coherence and remains effective even when trained on relatively limited datasets. The model was trained on 25 C2 vertebrae from the VerSe dataset and subsequently evaluated on ten independent specimens. The resulting morphometric measurements were consistent across all test specimens and fell within the anatomical ranges reported in the literature, thus supporting the anatomical plausibility and methodological reliability of the proposed approach. While the current implementation should be regarded as a methodological proof of concept due to the limited training dataset, this framework demonstrates the potential of enhanced statistical shape models for automated, reproducible, and anatomically consistent morphometric analysis of complex vertebral structures.

Keywords: Automatic feature recognition | Biomedical image analysis | Statistical shape modelling

Abstract: Background and objective: Accurately measuring cervical vertebrae dimensions is crucial for diagnosing conditions, planning surgeries, and studying morphological variations related to gender, age, and ethnicity. However, traditional manual measurement methods, due to their labour-intensive nature, time-consuming process, and susceptibility to operator variability, often fall short in providing the objectivity required for reliable measurements. This study addresses these limitations by introducing a novel computer-based method for automatically identifying the dimensional features of human cervical vertebrae, leveraging 3D geometric models obtained from CT or 3D scanning. Methods: The proposed approach involves defining a local coordinate system and establishing a set of rules and parameters to evaluate the typical dimensional features of the vertebral body, foramen, and spinous process in the sagittal and coronal planes of the high-density point cloud of the cervical vertebra model. This system provides a consistent measurement reference frame, improving the method's reliability and objectivity. Based on this reference system, the method automates the traditional standard protocol, typically performed manually by radiologists, through an algorithmic approach. Results: The performance of the computer-based method was compared with the traditional manual approach using a dataset of nine complete cervical tracts. Manual measurements were conducted following a defined protocol. The manual method demonstrated poor repeatability and reproducibility, with substantial differences between the minimum and maximum values for the measured features in intra- and inter-operator evaluations. In contrast, the measurements obtained with the proposed computer-based method were consistent and repeatable. Conclusions: The proposed computer-based method provides a more reliable and objective approach for measuring the dimensional features of cervical vertebrae. It establishes a procedural standard for deducing the morphological characteristics of cervical vertebrae, with significant implications for clinical applications, such as surgical planning and diagnosis, as well as for forensic anthropology and spinal anatomy research. Further refinement and validation of the algorithmic rules and investigations into the influence of morphological abnormalities are necessary to improve the method's accuracy.

Keywords: Biomedical engineering | Cervical vertebrae | CT measures standardization

Abstract: This paper introduces a novel triangular encoding technique specifically designed for identifying geometric correspondences in structured light three-dimensional (3D) imaging. The proposed method, based on a hybrid approach between pseudo-dot arrays and M-arrays, overcomes limitations of existing encoding strategies by using a triangular pattern that directly encodes information in a 2D grid. The paper presents the theoretical framework for the encoding, a pseudo-algorithm for its application to 2D images, and a discussion of the algorithm's capabilities and limitations. An interesting potential of using this pattern is its ability to reduce the post-processing time required to generate 3D models, as it can inherently determine the connectivity of the vertices in the projected mesh. The proposed triangular encoding approach is shown to be particularly effective for dynamic 3D scene reconstruction and for applications requiring robust information encoding, such as QR codes. Additionally, the paper outlines the potential for future work in developing a decoding strategy and further refining the encoding system using multiple states, such as RGB colors.

Keywords: 3D imaging | combinatorial geometry | encoding techniques | pattern recognition | structured light

Abstract: This paper presents a novel workflow for designing and fabricating patient-specific cranial implants and surgical guides using advanced CAD and 3D printing technologies. Developed at the T3Ddy Lab at Meyer Children’s Hospital, the methodology includes close collaboration between engineers and neurosurgeons, allowing for rapid prototyping and real-time adjustments. The workflow involves designing a cutting guide for precise bone resection and a custom cranial implant for anatomical reconstruction, both using titanium alloy for its biocompatibility and mechanical strength. The setup enhances efficiency, ensuring precise device fit and improving surgical outcomes. The paper presents the general framework established to design custom made medical devices for skull repairing surgery. The CAD modeling phase of the surgical guide and cranial implant are described in detail, highlighting developed solutions to improve the effectiveness of the technology. The proposed workflow was validated in multiple clinical cases, demonstrating improved surgical precision, reduced operative time, and enhanced recovery.

Keywords: 3D Printing | CAD | Cranial Implant | Cranioplasty | Craniotomy | Surgical Guide

Abstract: Intraosseous access is a critical emergency procedure for introducing fluids and blood components into the systemic circulation, necessitating thorough training for healthcare personnel. In collaboration with Meyer Children’s University Hospital IRCCS, the Department of Industrial Engineering at the University of Florence has developed a high-fidelity, low-cost pediatric simulator specifically for intraosseous access in the proximal tibia. Using Materialise Mimics 26® software, anonymized tomographic images of a 5-year-old patient were processed to obtain the three-dimensional geometry of relevant anatomical structures: tibia, fibula, distal femur, muscles, and skin. These models were further refined with Geomagic DesignX® for the final simulator design. The simulator features silicone replicas for soft tissues, with rigid structures and silicone casting molds produced through Fused Deposition Modeling. Preliminary tests were conducted to select suitable materials, which were then evaluated by specialized medical personnel using the EZ-IO® device to ensure accurate haptic feedback. The resulting simulator provides a realistic platform for intraosseous access training, enabling healthcare practitioners to enhance their procedural skills and ensure patient safety.

Keywords: additive manufacturing | intraosseous access | pediatric mannequin

Abstract: Background & objective: Human vertebrae are analysed and measured for various purposes, including to study anatomy, to diagnose illness, and to evaluate therapies. Achieving an accurate morphological and dimensional characterisation of three-dimensional (3D) vertebrae relies on the precise recognition of their features. Traditionally, these features, lacking defined edges, have been identified manually through a time-consuming, poorly repeatable, and poorly reproducible process. To the authors’ knowledge, there is only one method published in the literature able to automatically recognise all the most important vertebral features: the algorithmic feature recognition method (AFRM). It requires a high-density point cloud as input, the presence of all morphological features, even if incomplete, and incurs high computational costs. This research aims to propose an improved version of the AFRM to overcome its limitations. Methods: The proposed approach combines the robustness of AFRM to provide the semantic segmentation of a 3D healthy human vertebra with the ability of the enhanced statistical shape model (eSSM) to transfer information among different models. Specifically, AFRM provides the semantic segmentation of the mean shape of the eSSM, while the latter transfers this information to target shapes. Results: The eSSM was developed using 20 training samples of healthy adult male L2 vertebrae. The test samples included five healthy vertebrae and four vertebras with large missing parts. None of the test shapes were included in the training set. The novel approach could accurately recognise morphological features without the constraints that affect the AFRM. Conclusion: The proposed method guarantees reliable and automated segmentation through AFRM, exploiting the eSSM's ability to provide results even when dealing with sparsely populated or partially incomplete target models, significantly reducing the computational load.

Keywords: 3D medical image analysis | Bio-informatics | Computer methods for vertebra analysis | Shape segmentation | Statistical Shape Analysis

Abstract: Lung cancer is the second neoplasia for incidence and the leading cause of death from neoplasia in the world. A consolidated practice for lung cancer early diagnosis and staging is EBUS TBNA (EndoBronchial UltraSound-guided TransBronchial Needle Aspiration). Despite being a low-risk procedure, its success highly depends on the medical staff’s skills, who therefore require appropriate training. With the future aim of developing a novel realistic EBUS TBNA simulator that also allows tissue sampling, in this paper, the authors propose a simplified representation of the mediastinum to define a suitable layout. As far as the authors know, the physical commercially-available simulators have poor echogenic properties, do not allow tissue sampling, and can be quite expensive. The project was carried out within Custom3D, a joint laboratory between Careggi Hospital of Florence and the Department of Industrial Engineering of the University of Florence, under the request of the interventional pneumology ward. The model was validated by an expert medical doctor who assessed its anatomical accuracy and the suitability of its mechanical and acoustic properties. Moreover, the possibility of performing lymph node needle aspiration is an added value that promises to bring the EBUS TBNA simulation to a new level of realism.

Keywords: EBUS TBNA | echogenic | mannequin | simulation

Abstract: This article presents a methodology for the design and production of custom prostheses for complex surgical interventions on long bones due to oncological surgical treatment. This type of intervention considers the complete or partial removal of bone tissue that might be affected by bone tumors. In this scenario it is important to limit the loss of functionality of the patients’ joints. Accordingly, it is important to salvage, whenever possible, the original articulation surfaces of the joints; nevertheless, a complete evaluation of the tumor extension and of the state of bone tissue might be difficult to be performed in the preparation phase. The article presents an approach for geometrical modelling of a modular prosthesis for long bones, that leaves the surgeon free to tailor the resection according to their feedback in the operating theatre. Specifically, the devised methodology allows to salvage part of the original bone by switching modules of the prosthesis. The dissertation is tackled from a technical perspective, taking into account the constraints and key features that need to be considered in the design and production of a long bone prosthesis via additive manufacturing technologies. The methodology is presented with reference to a complex custom prosthesis design that was carried out with the support of T3Ddy’s - Personalized pediatrics by inTegrating 3D aDvanced technologies research laboratory.

Keywords: Additive Manufacturing | Custom prosthesis | Design for Additive Manufacturing

Abstract: Background and objective: The ability to accomplish a consistent restoration of a missing or deformed anatomical area is a fundamental step for defining a custom implant, especially in the maxillofacial and cranial reconstruction where the aesthetical aspect is crucial for a successful surgical outcome. At the same time, this task is also the most difficult, time-consuming, and complicated across the whole reconstruction process. This is mostly due to the high geometric complexity of the anatomical structures, insufficient references, and significant interindividual anatomical heterogeneity. Numerous solutions, specifically for the neurocranium, have been put forward in the scientific literature to address the reconstruction issue, but none of them has yet been persuasive enough to guarantee an easily automatable approach with a consistent shape reconstruction. Methods: This work aims to present a novel reconstruction method (named HyM3D) for the automatic restoration of the exocranial surface by ensuring both the symmetry of the resulting skull and the continuity between the reconstructive patch and the surrounding bone. To achieve this goal, the strengths of the Template-based methods are exploited to provide knowledge of the missing or deformed region and to guide a subsequent Surface Interpolation-based algorithm. HyM3D is an improved version of a methodology presented by the authors in a previous publication for the restoration of unilateral defects. Differently from the first version, the novel procedure applies to all kinds of cranial defects, whether they are unilateral or not. Results: The presented method has been tested on several test cases, both synthetic and real, and the results show that it is reliable and trustworthy, providing a consistent outcome with no user intervention even when dealing with complex defects. Conclusions: HyM3D method proved to be a valid alternative to the existing approaches for the digital reconstruction of a defective cranial vault; furthermore, with respect to the current alternatives, it demands less user interaction since the method is landmarks-independent and does not require any patch adaptation.

Keywords: Bioinformatics | Computed aided design | Cranioplasty | Statistical shape model | Surface Interpolation

Abstract: Orbital exenteration is a radical and disfiguring operation. It is still under debate the absence of correlation between the term describing the resulting orbital defect and the type of reconstruction. Authors' goal was to propose a consistent and uniform terminology for Orbital Exenteration surgery in anticipation of patients' tailored management. Twenty-five patients who underwent orbital exenteration between 2014 and 2020 were reviewed. A parallel comprehensive literature review was carried on. Five different types of orbital exenteration where outlined. Multiple reconstructive procedures were enclosed. An algorithm for orbital reconstruction was proposed based on anatomic boundaries restoration. Eyelid removal was first considered as an independent reconstructive factor, and both orbital roof and floor were indicated as independent reconstructive goals, which deserve different defect classification. In our opinion, this algorithm could be a useful tool for patient counseling and treatment selection, which might allow a more tailored patient care protocol. Level of Evidence Level III.

Keywords: defect classification | orbital anatomy | orbital exenteration | orbital reconstruction | reconstructive flowchart

Abstract: When dealing with craniofacial impairments, restoring the morphological condition is as crucial as restoring the functional ones to avoid psychosocial disabilities for the patient. For this aim, the accurate location of the midsagittal plane is essential for performing reliable symmetry analyses and guiding effective surgery planning. To provide a fully automatic and landmark-independent approach, capable of providing a midsagittal plane for craniofacial skeleton even from anatomical models with high asymmetries, an innovative method, called MaWR-method, was developed by the authors in a previous work. This paper further investigates the MaWR-method by evaluating its capacity to produce a successful outcome even in the worst-case scenario that may be considered in maxillofacial surgery, namely panfacial fractures. In all the test cases considered in this work, the method proved robust and reliable in its original design. It provided a consistent result requiring no user involvement, even when dealing with extreme asymmetries because of extensive and complex fractures.

Keywords: Feature recognition | Mid-sagittal plane | Symmetry analysis | Symmetry plane detection

Abstract: This work aims at the development of a streamlined and robust CAD procedure to design load-bearing implants. The methodology used to reach this result is explained in the paper: 3D digital anatomy reconstruction of defective structures of the patient is performed with the help of a statistical shape model; subsequently, a CAD modelling tool based on implicit modelling (i.e., nTopology) is used to implement a repeatable semi-automatic procedure that can be performed by a competent user with little effort and limited manual operations. Once that the main shape of the implant is defined, lattice geometries are generated to improve mechanical properties of the implant. The procedure requires as inputs the reconstructed anatomy of the patient and a series of clinical indications on the type of implant that needs to be designed. The paper discusses the development of the whole procedure; achieved results, which include the application of the whole framework on multiple case studies, are presented. The procedure allows the design of a whole implant in 20 minutes circa.

Keywords: CAD Design Automation | Custom Implant | Additive Manufacturing | Implicit Modelling | nTopology

Abstract: Background: Orthopaedic and Trauma surgery is expected to undergo profound trans-formation as a result of the adoption of 3D technology. Among the various applications, patient specific manufacturing of splints and casts would appear to be, particularly in children, an interesting implementation. This study aims to assess the safety of patient specific 3D casts obtained with a newly developed 3D-scanning devise in a small case series. We therefore conducted a clinical outcome and pre-marketing study in 10 consecutive patients with distal radius fractures treated at an Academic Level I Pediatric Trauma Center. After the application of the 3D cast, patients underwent three consecutive evaluations in the following 21 days. The main outcome measurements were: pain, skin lesions and general comfort, and acceptance of the cast. The three domains were measured with the Visual Analogue Scale (VAS), the NPUAP/EPUAP classification and the Positive affect-Negative affect Scale for Children (PANAS-C), the Self-Assessment Manikin (SAM) clinical psychology tests and a Likert-type five item questionnaire, respectively. A final mechanical analysis of the cast was carried out to confirm product integrity. Results: The results obtained were consistently positive in the investigated domains of general comfort, efficacy of contention and mechanical integrity of the 3D-printed cast as well as in the practicability of the supply chain. Conclusions: This study provides Level IV evidence that patient specific 3D printed casts obtained with a specifically designed software were safe in the management of “buckle” fractures of the distal radius in children. These results encourage to extend the technology to the treatment of more demanding fractures.

Keywords: 3D printing | customized implants | orthopedic device | orthosis modeling | pediatrics | personalized medicine | reverse engineering

Abstract: Dealing with the design of personalized medical devices, mass production is not an option that can be hypothesized. Indeed, a cumbersome production process must be considered in such cases, mainly to account for a delicate design phase that needs to take into consideration, as input, an anatomy that vary each time. This article discusses the development of a statistical tool able to support the design of patient-specific devices. By expanding the classical formulation of the Statistical Shape Model (SSM) with the introduction of multiple levels of information within the same model, the authors have experimented with the concept of an “enhanced SSM”. While the traditional SSM only provides information on the variations that a class of shapes can manifest, the eSSM may include more levels of information. The article discusses two possible mathematical formulations of such statistical tool. Its application to the design of custom-made pelvic implants is discussed. Such application scenario is described starting from the generation of the eSSM for the pelvis. The features of interest considered in this paper are the centers of the acetabular regions of the pelvis, the segmentation of the anatomy in a series of semantical regions that must be considered when developing a load-bearing implant. Finally, the conclusions of this research are drawn and discussed together with possible future development of eSSMs.

Keywords: Biomedical engineering | Custom implant design | Human modelling | Pelvis | SSM | Statistical shape analysis

Abstract: The present paper presents the development of a novel procedure for the modeling of Surgical Cutting Guides (SCGs) exploiting an implicit modeling approach. As discussed in the text, this approach allows for a streamlined and efficient design of this type of medical device. A procedural approach based on the application of a series of a priori-known implicit modeling function allows the generation of personalized surgical guides starting from the i) patient’s anatomy and ii) clinical decisions made by the medical staff. The CAD procedure is detailed in the text; achieved results are discussed and compared with a traditional CAD modeling approach on three case studies.

Keywords: CAD | Implicit Modelling | Patient-Specific Instrument | Personalized Medical Device

Abstract: Cranioplasty is a procedure performed to repair defects in the human skull bone by surgically reconstructing the shape and function of the cranium. Several complications, both intraoperative and postoperative, can affect the procedure’s outcome (e.g., inaccuracies of the reconstructed shape, infections, ulcer, necrosis). Although the design of additive manufactured implants in a preoperative stage has improved the general quality of cranioplasties, potential complications remain significant, especially in the presence of critical skin tissue conditions. In this paper, an innovative procedure to improve the chances of a positive outcome when facing critical conditions in a cranioplasty is described. The proposed approach relies on a structured planning phase articulated in a series of digital analyses and physical simulations performed on personalized medical devices that guide the surgeon in defining surgical cuts and designing the implant. The ultimate goal is to improve the chances of a positive outcome and a fast recovery for the patient. The procedure, described in extenso in the paper, was positively tested on a cranioplasty case study, which presented high risk factors.

Keywords: Additive manufacturing | Cranioplasty | Patient-specific implant | Skull reconstruction

Abstract: The increasing availability of 3D anatomical models obtained from diagnostic images exploiting Reverse Engineering techniques allows the application of statistical analysis in the quantitative investigation of anatomical shapes variability. Statistical Shape Models are a well-established method for representing such variability, especially for complex forms like the anatomical ones. Not by chance, these models are widely used for medical applications, such as guiding segmentation of the diagnostic image and virtual reconstruction of incomplete anatomic region. The application of a statistical analysis on a set of shapes representing the same anatomical region essentially requires that shapes must be in correspondence, i.e. constituted by the same number of points in corresponding position. This work aims to compare two established algorithms, namely a modified version of the Iterative Closest Point and the non-rigid version of the Coherent Point Drift, to solve the correspondences’ problem in the construction of a Statistical Shape Model of the human cranium. The comparison is carried out on the models using the standard evaluation criteria: Generalization, Specificity and Compactness. The modified version of the Iterative Closest Point delivers a better Statistical Shape Model in terms of Generalization and Specificity, but not for Compactness, than the Coherent Point Drift-based model.

Keywords: Computer-Aided Technologies | Correspondences’ problem | Reverse Engineering | Statistical Shape Analysis | Statistical Shape Model

Abstract: The availability of advanced tools able to model complex geometries along with the relaxing of the constraints related to the manufacturing technologies are heavily transforming the design approach in many fields, including healthcare. The focus of this paper is on the optimization of porous lightweight cellular geometries in the orthopedic implants design: lattice structures have proven to fulfill the biological, mechanical, and technological constraints required in designing load bearing devices. The aim is to collect the information provided by the related literature to describe the effects induced by the selection of parameters designing lattice gyroid structures for orthopedic implants.

Keywords: custom metal implant | design for additive manufacturing | gyroid | metallic lattice structures | triply periodic minimal surface

Abstract: Designing an acquisition system for 2D or 3D information, based on the integration of data provided by different sensors is a task that requires a labor-intensive initial design phase. Indeed, the definition of the architecture of such acquisition systems needs to start from the identification of the position and orientation of the sensors observing the scene. Their placement is carefully studied to enhance the efficacy of the system. This often coincides with the need to maximize the surfaces observed by the sensors or some other metric. An automatic optimization procedure based on the Particle Swarm Optimization (PSO) algorithm, to seek the most convenient setting of multiple optical sensors observing a 3D scene, is proposed. The procedure has been developed to provide a fast and efficient tool for 2D and 3D data acquisition. Three different objective functions of general validity, to be used in future applications, are proposed and described in the text. Various filters are introduced to reduce computational times of the whole procedure. The method is capable of handling occlusions from undesired obstacle in the scene. Finally, the entire method is discussed with reference to 1) the development of a body scanner for the arm-wrist-hand district and 2) the acquisition of an internal environment as case studies.

Keywords: 3D scanning | Body scanner | Computer graphics | Optical sensors | PSO | Sensor placement | Visibility analysis

Abstract: The application of CAx tools in surgery is representing a breakthrough for clinical practice, both in terms of effectiveness and costs. Working directly on the patient’s own diagnostic images, this approach provides powerful tools for pre-operative simulation, complex-surgery planning, quantitative evaluation of asymmetry or dysmorphism and for the design of the patient-specific instrumentation. To exploit its full potential, methodologies are being developed to automatize and simplify the existing tools and strategies, in order to make them available also to less experienced CAx users, or directly to the surgeons. With this aim, it is proposed a methodological procedure to automatically create a Statistical Shape Model of the cranial vault starting from a Training Set of pathologically unaffected adult crania. The Statistical Shape Model is useful as a template for a data-driven restoration of the physiological shape of the considered anatomy. The proposed procedure provides a reliable strategy for robust automatic detection of shape correspondence. Not requiring any user intervention, the number of samples in the Training Set can be increased at will to consequently increase the variability, and therefore the accuracy, of the resulting parametric model.

Keywords: CAx | Reverse engineering | Statistical Shape Model

Abstract: Additive Manufacturing technologies are proving to be reliable alternatives to traditional ones. Because of their capability to allow short-run production with very low changeover costs and minimal setup, additive manufacturing technologies represent the best choice in case of low-volume highly customized productions. Furthermore, they represent the only alternative to manufacture lattice components, characterized by a complex meso-structure. To date, the main limitation of additive manufacturing is represented by a limited selection of printable materials. In addition, despite lots of information can be found about the mechanical characterization of the available printable materials, there is not as much information regarding their mechanical and geometrical behavior in high-temperature applications. Especially for thermoplastics, the lack of information limits the possibilities for the selection of adequate material, affecting the effectiveness of the design. In this work, a close inspection of the specific literature has been done, with the aim to gather information on the available printable materials suitable for high-temperature applications.

Keywords: 3D printed materials | Additive manufacturing | High temperature

Abstract: In cranioplasty surgery, achieving an effective aesthetic shape restoration of the cranial vault is the most important issue to ensure a proper outcome in terms of social and psychological benefits for the patient. To date, the most advanced approach uses CT/MRI data to reconstruct, in a pre-operative stage, the 3D anatomy of the defective skull in order to design a patient-specific prosthesis. In the last years, several techniques have been proposed to improve the applicability of such approach in the clinical practice, but the analysis of the related literature shows still open issues, due to the wide anatomical variability and complexity of the craniofacial anatomy that needs to be retrieved. With the aim to overcome the State-of-the-Art drawbacks, a new semi-automatic hybrid procedure for repairing unilateral or quasi-unilateral (i.e. a single defect slightly passing the sagittal plane) cranial defects is presented. The novel approach is hybrid because a surface interpolation for filling the hole is used together with a template-based reconstruction guided by the healthy counterpart. The procedure, being landmark-independent and avoiding any patch adaptation, represents a valid alternative for the existing approaches also in terms of user's burden, requiring less time consuming and less cumbersome operations. In addition, a new evaluating technique able to measure the symmetry of the reconstruction as well as the continuity between patch and healthy bone is proposed to test the procedure performance. Several test cases have been then addressed to prove the effectiveness and repeatability of the proposed procedure in reconstructing large-size defects of the skull.

Keywords: CAD | Cranioplasty | Reverse Engineering | Skull Reconstruction

Abstract: The introduction of the vacuum bell (VB) for the conservative treatment of Pectus Excavatum (PE) has led to a new non-invasive alternative to thoracic surgery. The VB works by elevating the chest as long as a negative differential pressure is internally assured. In recent years studies have been conducted to validate this type of treatment and to outline its correct use; results show a short-term PE improvement when the device is worn for a minimum of 30 min (twice a day) up to a maximum of several hours a day for 12–15 months. Although the worldwide diffusion of VB devices increases year after year, its ability to lift the chest during treatment with respect to the applied pressure has begun to be evaluated only recently. In this paper, a new instrument for measuring chest elevation during treatment is presented and validated. The proposed system consists of two measurement devices: a commercial instrument for the detection of the negative pressure inside the VB, and a specifically developed optical system for the detection of chest movement. The effectiveness of the proposed system, tested on five paediatric patients, paves the way to the objective definition of an optimised patient specific VB scheme of use.

Keywords: Image processing | Optical measurement | Pectus Excavatum | Vacuum bell

Abstract: The accurate location of the mid-sagittal plane is fundamental for the assessment of craniofacial dysmorphisms and for a proper corrective surgery planning. To date, these elaborations are carried out by skilled operators within specific software environments. Since the whole procedure is based on the manual selection of specific landmarks, it is time-consuming, and the results depend on the operators' professional experience. This work aims to propose a new automatic and landmark-independent technique which is able to extract a reliable mid-sagittal plane from 3D CT images. The algorithm has been designed to perform a robust evaluation, also in the case of large defect areas. The presented method is an upgraded version of a mirroring-and registration technique for the automatic symmetry plane detection of 3D asymmetrically scanned human faces, previously published by the authors. With respect to the published algorithm, the improvements here introduced concern both the objective function formulation and the method used to minimize it. The automatic method here proposed has been verified in the analysis of real craniofacial skeletons also with large defects, and the results have been compared with other recent technologies.

Keywords: Cranio-maxillofacial | Feature recognition | Medical imaging | Mid-sagittal plane | Symmetry analysis