Methods for medical applications

The paper proposes a new recognition rule to automatically identify the spine line by detecting vertebral apophyses from discrete models of human backs collected by 3D scanning. Unlike previous 3D optical approaches, the process described here aims to directly detect spinal apophyses, following the posturologist's method. These anatomical landmarks are identified not as areas of the back surface with specific shapes, but by searching for appropriate local shape perturbations. Except for vertebral prominences that are convex regions, spinal apophyses are generally unrelated to specific surface shapes. The rule has been tested on several human backs. For each, an experienced operator identified the spinal apophyses from palpation and indicated their position by applying an adhesive marker on the back surface. These positions are used as a reference to compare the vertebral apophyses automatically localized by the methodology proposed here. The experimental results show that the rule discriminates well even blurred vertebral prominences.

Keywords: 3D optical methods , Local shape analysis , Shape index , Spinal apophyses recognition , Spine line

(1) Background: Orthopedic surgery has been transformed by 3D-printed personalized instruments (3DP-PSIs), which enhance precision and reduce complications. Hospitals are adopting in-house 3D printing facilities, using cost-effective methods like Fused Deposition Modeling (FDM) with materials like Polylactic acid (PLA) to create 3DP-PSI. PLA's temperature limitations can be overcome by annealing High-Temperature PLA (ann-HTPLA), enabling steam sterilization without compromising properties. Our study examines the in vivo efficacy of ann-HTPLA 3DP-PSI in pediatric orthopedic surgery. (2) Methods: we investigated safety and efficacy using ann-HTPLA 3DP-PSI produced at an “in-office” 3D-printing Point-of-Care (3DP-PoC) aimed at correcting limb deformities in pediatric patients. Data on 3DP-PSI dimensions and printing parameters were collected, along with usability and complications. (3) Results: Eighty-three ann-HTPLA 3DP-PSIs were utilized in 33 patients (47 bone segments). The smallest guide used measured 3.8 cm3, and the largest measured 58.8 cm3. Seventy-nine PSIs (95.2%; 95% C.I.: 88.1–98.7%) demonstrated effective use without issues. Out of 47 procedures, 11 had complications, including 2 infections (4.3%; 95% CI: 0.5–14.5%). Intraoperative use of 3DP-PSIs did not significantly increase infection rates or other complications. (4) Conclusions: ann-HTPLA has proven satisfactory usability and safety as a suitable material for producing 3DP-PSI in an “in-office” 3DP-PoC.

Keywords: 3D-printing , annealing , Fused Deposition Modeling , high-temperature polylactic acid , in vivo , orthopedic surgery , patient-specific instrument , pediatrics , polylactic acid , sterilization

Background: In recent years, the treatment of wrist fractures has been the focus of numerous studies, particularly in the development of casts modeled on the patient's anatomy using additive manufacturing techniques. A 3D printed cast offers several advantages over traditional treatment methods, including washability, lightness, and ventilation. Objective: This work introduces an automatic procedure for designing patient-specific wrist orthoses from a 3D scan of the arm using open-source mesh-processing libraries. Methods: The procedure consists of seven steps that generate a customized orthosis model. Due to the absence of a single library capable of completing the entire modeling process, we defined the best execution strategy for each step and established a communication flow between the various blocks. Results: The resulting orthosis comprises two halves, secured by three appropriately positioned bands and perforated with ventilation holes. The modeling procedure takes approximately 5 min to complete and was evaluated on 20 scans of arms of different shapes and sizes. The process proved to be fast, reliable, and suitable for direct use by medical personnel. Conclusions: The developed automatic procedure for designing patient-specific wrist orthoses is efficient and effective, facilitating the use of 3D printed casts in medical practice.

Keywords: 3D modelling , 3D printed orthosis , Personalized medicine , Reverse engineering , Wrist orthosis

Purpose. High-fidelity mannequins are increasingly used to train the medical staff on many medical procedures. Lately, a new challenge regarding echogenic materials to build ultrasound-responding phantoms has emerged. The challenge is to find materials with a suitable combination of ultrasound velocity and consistency to the touch. Methods. Bibliographic research was performed to identify materials with promising stiffness, shape retention, and ultrasound velocity combinations. As-standardized-as-possible specimens were realized and tested using an A-mode ultrasound machine to evaluate the US velocity through them. Four differently doped silicones, five gelatin-based materials, five synthetic gelatins, and a 3D printable resin were included in the study. After being tested, the materials were monitored for 12 days to assess their durability and shape retention and tested again to evaluate the ultrasound velocity's stability. In the paper, the results of the characterization and follow-up of the materials are presented. Results. Outcomes show that gelatins are exceptional soft tissue-mimicking materials in terms of ultrasound velocity and consistency to the touch, but are poor in terms of overtime stability and therefore suitable for disposable short-term phantoms only. Doped silicones present lower ultrasound velocity compared to the reference value of 1540 m/s found in the literature, but excellent overtime stability, and shape retention properties. Values close to biological ones were also given by the Elastic 50A and by polyvinyl chloride plastisol. Conclusion. The paper gives a quantitative overview of the fidelity of both already-in-use and non-conventional materials, focusing on the ultrasound velocity value through them and their longevity in terms of macroscopically observed dehydration, shape retention, and bacterial onset.

The treatment of burn scars is a hotly debated and delicate subject since ineffective therapy can significantly lower quality of life. Ideally, medical evaluation should leverage objective assessments of progress over time to provide an adequate assessment of scar health and related treatment. In contrast, common clinical practice involves medical examination that rely on subjective assessment scales such as Vancouver Scar Scale and the Patient and Observer Scar Assessment Scale. Recently, extraction of objective parameters for the investigation of scar surface were studied by objectively analyzing the surface topography and extracting scar roughness through a transposition of standard mechanical surface evaluation methods, which are based on ISO 4287 and ISO 4288, to the clinical field. The most advanced methods analyze the scar roughness globally and after subdividing it in sub-patches of pre-fixed dimension. In both cases, it is not considered that the scar may be located in non-planar portions of the body, therefore, roughness values are dependent from the principal roughness evaluation direction. In the present work these shortfalls are overcome using a systematic procedure to subdivide the patches in a consistent manner and analyze smaller portions of the surface providing a roughness value independent of the filtering direction.

Keywords: 3D scar model , Automatic assessment , Burn scar , Surface roughness

Extended Reality (XR) has experienced rapid growth in the past decades, proving to be a viable alternative to conventional practices in all the fields. Professional VR solutions have been developed; giving people access to virtual scenarios that are very similar to their real counterparts owing to the high level of realism reached with the latest technologies. Wearing a VR headset, the users can explore spaces they've never been before in real life, getting familiar with them without the dangers of the real-world circumstances. This principle paved the way to X-Reality development in the context of training for harmful procedures in many professional fields, and medicine makes no exception, being particularly involved in searching for novel methods to educate experts. This research explores the potential of X-Reality in medical training, proposing an innovative virtual training system to let medical personnel perceive ionizing radiation in a virtual scenario. The virtual environment was reconstructed with photogrammetry and within it users are able to fix their bad habits related to radiation exposure during an orthopedic surgery. To improve the XR system's effectiveness a short beta test was set up involving medical experts, with some interesting regarding the benefits and issues of the XR system.

Keywords: Ionizing Radiation , Orthopedic Surgery , Photogrammetry , Virtual Reality , Virtual training , X-Reality

Despite its significant advantages in terms of design freedom and the wide range of processable materials, the Binder Jetting technology has not yet received substantial attention in the healthcare field, especially concerning the fabrication of metal components. Hence, the paper investigates how this technology could be exploited to innovate the medical instrument field. Based on selected case studies, some preliminary design indications are derived on how to properly consider the various phases (i.e., printing, depowdering, and sintering) and related challenges of the Binder Jetting process.

Keywords: additive manufacturing , binder jetting , biomedical design , design for additive manufacturing

As is widely recognized, advancements in new design and rapid prototyping techniques such as CAD modeling and 3D printing are pioneering individualized medicine, facilitating the implementation of new methodologies for creating customized orthoses. The aim of this paper is to develop a new automatic technique for producing personalized orthoses in a straightforward manner, eliminating the necessity for doctors to collaborate directly with technicians. A novel design method for creating customized wrist orthoses has been implemented, notably featuring a generative algorithm for the parametric modeling of the orthosis. To assess the efficacy of the developed algorithm, a case study was conducted involving the design and rapid prototyping of a wrist orthosis using Fused Deposition Modeling (FDM) technology. Subsequently, the developed algorithm was tested by clinicians and patients. The results obtained indicate that the implemented algorithm is user-friendly and could potentially enable non-expert users to design customized orthoses. These results introduce innovative elements of originality within the CAD modeling, offering promising solutions to the challenges associated with the design and production of customized orthoses. Future developments could consist of a better investigation regarding the parameters that influence the accuracy of the scanning and of the printing processes.

Keywords: additive manufacturing , CAD , generative design , reverse engineering , wrist orthosis

Background: Telemedicine has emerged as a potential solution to mitigate the significant greenhouse gas emissions of the healthcare sector. A comprehensive evaluation is required to quantify the environmental benefits of its implementation. Objectives: The study aims to compare the environmental sustainability of in-person and virtual examinations for heart failure patients. Methods: A standard life cycle assessment has been applied to quantify the equivalent CO2 of direct and indirect activities required to release a medical examination (virtual or physical) for a patient in an Italian hospital. Inputs of the analysis include electronic devices of hospital and patients, energy consumption, wastes, internet usage and patient travel. Depending on the type of visit (virtual or physical), inputs have been processed differently, considering actual consumption and utilization. Results: Televisit reduces emissions from 9.77 kgCO2e to 0.41 kgCO2e. Transport and internet data use are key inputs for in-person (i.e., 98%) and telemedicine visits (i.e., 72%), respectively. Discussion: Given the frequent car travels, telemedicine emerges as a tool to improve environmental benefits and reduce time for patients and caregivers.

Keywords: carbon footprint , environmental impact , life cycle , sustainable development , telemedicine

In this study, a new methodology for designing and creating a custom-made template for maxillofacial surgery has been developed. The custom-made template can be used both for cutting and repositioning of the mandible arches for executing a BSSO (bilateral sagittal split osteotomy) treatment. The idea was developed in order to give the possibility of using a custom-made template with standard plates, thus reducing long times, high costs and low availability of custom-made plates; this represents the proof of novelty of the proposed template, based on a well-established methodology. The methodology was completely developed in the CAD virtual environment and, after the surgeons' assessment, an in-vitro experiment by a maxillofacial surgeon was performed in order to check the usability and the versatility of the system, thanks to the use of additive manufacturing technologies. When computer-aided technologies are used for orthognathic surgery, there are significant time and cost savings that can be realised, as well as improved performance. The cost of the whole operation is lower than the standard one, thanks to the use of standard plates. To carry out the procedures, the proposed methodology allows for inexpensive physical mock-ups that enable the BSSO procedure to be performed.

Keywords: computer-aided surgery , low-cost procedure , orthognathic , standard plate , surgical template

Introduction: Flatfoot is a condition commonly seen in children; however, there is general disagreement over its incidence, characterization and correction. Painful flatfoot accompanied with musculoskeletal and soft tissue problems requires surgery to avoid arthritis in adulthood, the most common surgical approach being two osteotomies to the calcaneus and medial cuneiform bones of the foot. Objectives: This study focuses on the parametrization of these two bones to understand their bone morphology differences in a population sample among 23 normal subjects. Population differences could help in understanding whether bone shape may be an important factor in aiding surgical planning and outcomes. Methods: A total of 45 sets of CT scans of these subjects were used to generate surface meshes of the two bones and converted to be iso-topological meshes, simplifying the application of Generalized Procrustes Analysis and Principal Component Analysis, allowing the main sources of variation between the subjects to be quantified. Results: For the calcaneus, 16 Principal Components (PCs) and, for the medial cuneiform, 12 PCs were sufficient to describe 90% of the dataset variability. The quantitative and qualitative analyses confirm that for the calcaneus PC1 describes the Achilles attachment location and PC2 largely describes the anterior part of the bone. For the medial cuneiform, PC1 describes the medial part of the bone, while PC2 mainly describes the superior part. Conclusion: Most importantly, the PCs did not seem to describe the osteotomy sites for both bones, suggesting low population variability at the bone cutting points. Further studies are needed to evaluate how shape variability impacts surgical outcomes. Future implications could include better surgical planning and may pave the way for complex robotic surgeries to become a reality.

Keywords: calcaneus , flatfoot , medial cuneiform , parametrization , pes planus , principal component analysis

In recent years, additive manufacturing has been expanding rapidly in several sectors, including marine, aerospace and civil, offering broad design freedom and environmental/ecological advantages for the production of fully functional products. Particularly in the biomedical area, interesting manufacturing methods have recently been developed for the customisation of orthotic devices by automating the acquisition process and 3D printing. Today, in the development of complex geometries, it is necessary to meet certain design specifications, such as mechanical strength, surface finish, light weight, breathability and aesthetic appearance, which can potentially be met by manufacturing with 3D printers. This research deals with the development and implementation of organic bioplastic compounds based on polylactic acid (PLA) and organic by-products for additive manufacturing applications of customised orthotic parts. PLA, filled with reinforcements and additives, can be used to produce durable and functional parts for improved structural performance. By studying specific orthotic cases with CAD-CAE techniques, its potential mechanical properties will be evaluated and compared to highlight its performance comparable or even superior to that of classical PLA. The proposed methodology reduces production costs and environmental impact. Thanks to the presence of reinforcements and additives, the new organic bioplastic compounds are more biodegradable, while improving some of the functionality and comfort requirements of customised orthoses.

Keywords: biodegradability , biomedical orthosis devices , mechanical properties characterization , Organic bio-composite filament , Reverse Engineering

Integrating remote Internet of Things (IoT) laboratories into project-based learning (PBL) in higher education institutions (HEIs) while exploiting the approach of technology-enhanced learning (TEL) is a challenging yet pivotal endeavor. Our proposed approach enables students to interact with an IoT-equipped lab locally and remotely, thereby bridging theoretical knowledge with practical application, creating a more immersive, adaptable, and effective learning experience. This study underscores the significance of combining hardware, software, and coding skills in PBL, emphasizing how IoTRemoteLab (the remote lab we developed) supports a customized educational experience that promotes innovation and safety. Moreover, we explore the potential of IoTRemoteLab as a TEL, facilitating and supporting the understanding and definition of the requirements of remote learning. Furthermore, we demonstrate how we incorporate generative artificial intelligence into IoTRemoteLab's settings, enabling personalized recommendations for students leveraging the lab locally or remotely. Our approach serves as a model for educators and researchers aiming to equip students with essential skills for the digital age while addressing broader issues related to access, engagement, and sustainability in HEIs. The practical findings following an in-class experiment reinforce the value of IoTRemoteLab and its features in preparing students for future technological demands and fostering a more inclusive, safe, and effective educational environment.

Keywords: education , educational technology , formative feedback , generative artificial intelligence , hands-on learning , interactive learning , internet of things , project-based learning , remote laboratory , technology-enhanced learning , user–computer interface

Phantoms play a crucial role in planning and simulating surgical procedures, evaluating new medical devices, and training purposes. Current simulators, such as human cadavers, animal models, and virtual reality systems, are quite expensive and not easily accessible. This research aims to design and develop an affordable 3D replica of a child's head for paediatric neurosurgery. The process began with a Magnetic Resonance Imaging (MRI) scan of a child's head. Afterward, a phantom was fabricated using nylon 3D printing and incorporating agar to replicate the skull and soft tissue. Moreover, Vaseline balls simulating tumors and a silicone skin were added to the phantom, enabling realistic MRI scans for surgical navigation. The functionality of a novel paediatric neurosurgery robot was then evaluated using the phantom as a realistic representation of a child's head. The cost-effectiveness of this approach makes it an ideal and reproducible method for surgical simulation and training objectives.

Keywords: 3D printing , Agar , MRI-visible phantom head , Neurosurgery

Pectus Excavatum is the most common form of thoracic deformity, characterized by the depression of the anterior chest wall. The most widely used non-surgical treatment involves the daily application of the Vacuum Bell, an external medical device that uses negative pressure to lift the sternum outwards. Nevertheless, the Vacuum Bell is only available in four sizes, making it difficult to apply to all possible cases of deformation. In addition, the variability of the surface to be treated and prolonged use can make the application uncomfortable, leading to decreased compliance and treatment discontinuation, thus compromising its effectiveness. In this context, the study was conducted with the aim of producing customized Vacuum Bell models. Starting with the 3D scanner acquisition of the patient, it was possible to reconstruct the three-dimensional model of the chest. Therefore, a specifically implemented MATLAB script enabled the identification of the surface to be treated and the semi-automatically drawing of the 3D curve outlying the deformation. Using this curve, via CAD software, it was then possible to proceed with the modelling of customized Vacuum Bells, whose profile adapts to the specific conformation of the patient's chest. Finally, a Vacuum Bell prototype was realized using additive manufacturing techniques.

Keywords: Additive manufacturing , Customized devices , Pectus Excavatum , Vacuum Bell

Detecting the lymph-node (LN) status plays a pivotal role in the management of patients with head and neck cancer (HNC). In this retrospective study we aimed to evaluate the possible benefits of using FDG PET radiomics to characterise the state of lymph nodes in HNC. Experimenting on a population of 51 lymph-nodes from 27 subjects we identified 21 radiomics features that were statistically different between the positive and negative lymph-node groups. Prediction models based on the radiomics features (PETRad) and semi-quantitative PET features (PETBase) were compared showing that PETRad provided better accuracy, sensitivity and specificity than the PETBase. We conclude that the use of radiomics features from FDG PET can improve the diagnostic accuracy of LN status in HNC.

Keywords: cervical lymph nodes , head and neck cancer , positron emission tomography , radiomics

[No abstract available] .

The human nose exhibits a huge variation in shape among individuals. All these variants alter the airflow through the nasal cavity and can impact how we smell odors. To acquire a better understanding of physiological and pathological functioning, it is important to study the effects of these modifications. SSM, or Statistical Shape Modelling, is a widely used methodology for considering morphological differences within a population. In the literature, only a few studies analyze nasal anatomy in its entirety, including paranasal sinuses, whose segmentation is particularly challenging due to their complexity and variability. This work aims at creating a highly accurate SSM for the nasosinusal complex. A traditional, greyscale thresholding-based segmentation approach was chosen, relying on Mimics software (Leuven, Belgium). 40 computed tomography (CT) datasets were considered. After segmentation, post-processing was performed to obtain watertight meshes using 3-Matic software (Leuven, Belgium), which was also used for the SSM generation. The generated model shows all relevant landmarks that typically characterize a nasosinual complex. 32 different modes are needed to explain 95% of the total variance. As a preliminary output, this study showed the feasibility and consistency of a statistical model of the nasosinusal anatomy. However, additional studies involving a larger sample size and a more robust validation process could be conducted.

Keywords: Anatomical Variation , Nose , Paranasal Sinuses , Principal Component Analysis , Statistical Shape Modelling

Reverse engineering (RE) is an evolving discipline in information science that offers computer-based reproductions of components, products, or even anatomical structures. Focusing on the human nose, various approaches, including basic 3D scanning, silicone rubber impressions, or medical imaging techniques, have been used for acquisition. Among these, just imaging techniques such as CT and MRI allow us to completely visualize the internal anatomy of the nose, also enabling three-dimensional reconstructions. Based on these considerations, this work aims to create an accurate 3D reconstruction of the nose, with a special focus on the nasal cavity, starting from a preoperative CT scan dataset. A thresholding-based segmentation approach was chosen to derive the inner volume occupied by the air. From this, a constant-thickness wall was generated with a hollowing operation. After further design modifications and improvements, the assembly was 3D printed with a stereolithography machine. The obtained model was then integrated into an experimental setup, including an odor sensor and a vacuum pump to generate airflow. Preliminary tests were run to evaluate the effectiveness of the proposed solution in guaranteeing signal detection. As a preliminary output, this study showed the feasibility of an experimental workbench to replicate human sniff. This was successfully tested with odorant molecules and an odor sensor. Now, more extensive tests will have to be conducted, even comparing results with those from numerical simulation.

Keywords: medical 3D printing , Nasal cavity , odor sensor , segmentation

Purpose: This study aims to examine the efficacy of 3D printing polymers to realistically mimic the fossa ovalis (FO) – a cardiac structure that is positioned in the interatrial septum – for simulating transseptal puncture (TP) procedures. Design/methodology/approach: Specimen of different materials and thicknesses were prepared and tested simulating the puncturing of the FO using a 12F ID/14F OD TP catheter. Force and tenting length results were compared with literature references. Scanning electron microscope images of the specimen were acquired to observe the perforated region as well as the structure of the specimen in the unaffected area. Findings: Significant changes in the properties of interest were registered for the same material on specimens tested at different moments after fabrication. Suturable vessel wall polyjet material offers the best characteristics to replicate FO anatomy and mimic its behavior to puncturing. Originality/value: The originality of the work lies in the test of different commercial materials. Similar works are already present in literature but specifically designed materials are used. Demonstrating that off-the-shelf materials could be viable for FO specimens would simplify the design of realistic TP simulators in the future.

Keywords: Additive manufacturing , Advanced manufacturing technologies , Fossa ovalis , Material testing , Mechanical properties of materials , Simulation training , Training devices , Transseptal puncture