Methods for medical applications

Background: Effective communication is a key factor in healthcare, essential for improving process efficiency and quality of care. This is particularly true in new services, e.g., the 3D printing service inside the hospital. Objectives: A web platform, called 3DSCT, has been developed to act as an interface between the three categories of operators involved in 3D printing: physicians, radiologists and engineers. Methods: The 3DSCT platform has been designed using Microsoft Visual Studio Code, enclosing.js scripts and HTML pages with the relative CSS formats. Results: When applied to a real 3D printing service, the 3DSCT platform provided an effective solution that streamlined the process of designing and manufacturing 3D-printed artifacts, from physician's request through development to printing. Conclusion: By incorporating the platform into the hospital management system, it will be possible to reduce the overall lead time and decrease the waste of time for the operators involved in 3D printing inside the hospital.

Keywords: 3D-Printing , Clinical Decision Support System , Communication

Background: With the spread of COVID-19, telemedicine solutions became crucial to release continuous and remote assistance to chronic patients. The rapid transition to telemedicine solutions did not allow a complete assessment of the user experience by both patients and medical personnel. Despite the well-known benefits in remote care, the lack of usability evaluation of already existing technologies for the vital signs measurement has emerged. A telemedicine platform must match video communication between patients and the medical staff with the possibility to measure vital parameters. Furthermore, technological assistance may overcome the unfamiliarity with telemedicine and drastically reduce the learning time for both patients and medical personnel. Objectives: The research work presents a method to improve the user experience of a telemedicine service based on the combination of televisits and telemonitoring with wearable sensors for heart failure patients. Skilled technological staff is proposed by the presented method to lead the learning process of both medical personnel and patients in order to reach a high level of usability in less than 6 months. Methods: The proposed method is composed of 5 steps: identification of technological staff and end users; selection of the telemedicine platform; design of questionnaires for usability analysis; training of clinicians and patients; final usability evaluation of the telemedicine platform by means of customized satisfaction questionnaires and Post-Study System Usability Questionnaires (PSSUQs). The methodological approach has been tested in collaboration with a heart failure clinic by involving 5 physicians, 5 nurses, 15 heart failure patients, a research engineer and 4 technicians. A platform with 3 wearable sensors has been chosen: a wireless thermometer, a finger pulse-oximeter and an undershirt have been used for the detection of ECG trace. While these devices allowed asynchronous measurements of physiological data, scheduled televisits have been used for direct communication between physicians and patients. Results: Satisfaction questionnaires of patients and clinicians reached respectively 65.18% and 65.83%, while PSSUQ scores were respectively 91.73% and 81.70%. Both groups of end users confirmed a good level of usability and their satisfaction about the ease of use and the perceived quality of the instrumentation. Moreover, 73% of patients did not require help from caregivers to use the kit of sensors. The results have been reached in 5.5 months according to the aim defined initially. Research engineers have played a crucial role in helping clinicians and patients to improve the user experience with the telemedicine platform. Conclusions: The high level of usability and satisfaction confirmed that the proposed methodological approach helps to learn the technological features of the telemedicine platforms, which are based on different types of technology, such as web applications, wearable sensors and virtual calls. The positive results with heart failure patients encouraged to plan further research studies by using the designed method with other categories of chronic patients.

Keywords: Health informatics , Heart failure patients , Telemedicine , Televisit , Usability analysis , Wearable sensors

Emotion recognition through machine learning techniques is a widely investigated research field, however the recent obligation to wear a face mask, following the COVID19 health emergency, precludes the application of systems developed so far. Humans naturally communicate their emotions through the mouth; therefore, the intelligent systems developed to date for identifying emotions of a subject primarily rely on this area in addition to other anatomical features (eyes, forehead, etc.). However, if the subject is wearing a face mask this region is no longer visible. For this reason, the goal of this work is to develop a tool able to compensate for this shortfall. The proposed tool uses the AffectNet dataset which is composed of eight class of emotions. The iterative training strategy relies on well-known convolutional neural network architectures to identify five sub-classes of emotions: following a pre-processing phase the architecture is trained to perform the task on the eight-class dataset, which is then recategorized into five classes allowing to obtain 96.92% of accuracy on the testing set. This strategy is compared to the most frequently used learning strategies and finally integrated within a real time application that allows to detect faces within a frame, determine if the subjects are wearing a face mask and recognize for each one the current emotion.

Keywords: Artificial intelligence , COVID19 , Emotion recognition , Facial Expression Recognition , Grad-CAM , Non-verbal communication

Pastes based on preceramic polymers have a great potential for direct ink writing of bioceramic scaffolds. In this paper, we discuss the fabrication of phase pure sphene (CaTiSiO5) bioceramics, developed by firing, at 1300°C, of silicone-based printed scaffolds containing CaCO3 and TiO2 as active fillers. As a proof of the flexibility of the combination of preceramic polymers and additive manufacturing technologies, several lattice geometries of increasing complexity were successfully explored. In particular, the approach allowed the fabrication of sphene scaffolds with gyroid-like structure exhibiting an impressive compressive strength, given the high porosity. Moreover, different lattice topologies of sphene scaffolds were compared also in terms of permeability.

Keywords: direct ink writing , mechanical strength , permeability , scaffold topologies , sphene bioceramics

Each year 65% of young athletes and 25% of physically active adults suffer from at least one musculoskeletal injury that prevents them from continuing with physical activity, negatively influencing their physical and mental well-being. The treatment of musculoskeletal injuries with the adhesive elastic kinesiology tape (KT) decreases the recovery time. Patients can thus recommence physical exercise earlier. Here, a novel KT based on auxetic structures is proposed to simplify the application procedure and allow personalization. This novel KT exploits the form-fitting property of auxetics as well as their ability to simultaneously expand in two perpendicular directions when stretched. The auxetic contribution is tuned by optimizing the structure design using analytical equations and experimental measurements. A reentrant honeycomb topology is selected to demonstrate the validity of the proposed approach. Prototypes of auxetic KT to treat general elbow pains and muscle tenseness in the forearm are developed.

New technological advances are changing the way robotics are designed for safe and dependable physical human–robot interaction and human-like prosthesis. Outstanding examples are the adoption of soft covers, compliant transmission elements, and motion control laws that allow compliant behavior in the event of collisions while preserving accuracy and performance during motion in free space. In this scenario, there is growing interest in variable stiffness actuators (VSAs). Herein, we present a new design of an anthropomorphic elbow VSA based on an architecture we developed previously. A robust dynamic feedback linearization algorithm is used to achieve simultaneous control of the output link position and stiffness. This actuation system makes use of two compliant transmission elements, characterized by a nonlinear relation between deflection and applied torque. Static feedback control algorithms have been proposed in literature considering purely elastic transmission; however, viscoelasticity is often observed in practice. This phenomenon may harm the performance of static feedback linearization algorithms, particularly in the case of trajectory tracking. To overcome this limitation, we propose a dynamic feedback linearization algorithm that explicitly considers the viscoelasticity of the transmission elements, and validate it through simulations and experimental studies. The results are compared with the static feedback case to showcase the improvement in trajectory tracking, even in the case of parameter uncertainty.

Keywords: Dynamic feedback linearization , Physical prototyping , Static feedback linearization , Upper-limb prosthesis , Variable stiffness

Soft robotic exoskeletons offer multiple advantages in the field of motor rehabilitation and assistance with activities of daily living This paper reports the design process of a mechanical arm for upper-limb soft exoskeleton testing. The main requirement of the test bench was to simulate five degrees of freedom (DOF) of the human arm, and in particular i) shoulder flexion/extension, ii) shoulder adduction/abduction, iii) shoulder medial rotation/lateral rotation, iv) elbow flexion/extension and v) forearm supination/pronation. An additional requirement included the possibility to alternatively lock each DOF. The final concept was designed using Autodesk Inventor and it is composed of 32 parts, 18 of which were particularly designed for this application. Topological optimisation and Finite Element Method (FEM) analysis were performed to some custom components to obtain the final design. The final concept was manufactured by means of additive manufacturing of PLA (polylactic acid) and laser cutting of PMMA (poly methyl methacrylate) sheets. After testing and validation, the prototype was able to meet the desired requirements and it can be used for soft-exoskeleton testing.

Keywords: Exoskeleton , Industrial sector , Motor rehabilitation , Upper limb , User feedback

Designing wearable robotic devices, such as exoskeletons, requires testing directly on the user to verify safety, comfort, and effectiveness. This is a time-consuming practice and not user-safe, especially during the experimental phase early stages. Things get even more complicated in the assistance and rehabilitation field because frail subjects are usually involved. This is also the case for the assistive hand exoskeleton system developed by the Mechatronics and Dynamic Modeling Laboratory of the University of Florence. With the aim of reducing patient involvement in the early stages of the device development and speeding up the prototyping process by allowing for frequent tests, a passive, customizable and kinetically-accurate hand replica has been designed.

Torsional deformities of the lower limb are common in children with cerebral palsy (CP)-determining gait problems. The mechanisms underlying transverse plane gait deviations arise from a combination of dynamic and static factors. The dynamic elements may be due to spasticity, contractures and muscle imbalances, while the static ones may result from excessive femoral anteversion, which decreases the efficiency of the hip abductors by reducing the muscular lever arms. A therapeutic approach has been identified in multi-level functional surgery for the lower limb. Treating the malalignments of the lower limb with femoral or tibial derotation provides optimal results, especially when supported by adequate biomechanical planning. This planning requires an integrated static-dynamic approach of morphological and functional evaluation, based on radiological measurements, physical examination and gait analysis. Instrumented gait analysis has been confirmed as essential in the evaluation and surgical decision making process for children affected by CP with transverse plane deformities. Computational simulations based on musculoskeletal models that integrate patient-specific CT morphological data into gait analysis can be used for the implementation of a surgical simulation system in pre-operative planning to test the possible effects of the different surgical treatment options on the torsional defects of the lower limbs. Recently, a computer-aided simulation process has been implemented in the preoperative planning of complex osteotomies for limb deformities in children. Three-dimensional (3D) digital models were generated from Computed Tomography (CT) scans, using free open-source software. The aim of this study is to integrate the patient-specific CT musculoskeletal model with morphological data and gait analysis data, with the personalized calculation of kinematic and kinetic parameters, which allow us to generate an “avatar” of the patient for a more in-depth evaluation of the gait abnormalities. The computational simulation platform proposed provides a realistic movable musculoskeletal model in a virtual environment, with the possibility of planning and monitoring the effects of virtual three-dimensional surgical corrections.

Keywords: avatar , cerebral palsy , computed tomography , derotation , gait analysis , musculoskeletal modeling , torsional deformities , virtual surgical planning

The present paper describes a procedure for the development and production of a physical model for surgical planning of a Left Ventricular Aneurysm. The method is based on the general approach provided in Otton et al. (2017) and was customized to seek a reliable and fast procedure for the production of a specific type of cardiac model – i.e. chambers of the left side of the heart. The paper covers all the steps: processing of the data, segmentation, modelling and 3D printing; details are provided for all the phases, in order to allow the reproduction of the achieved results. The procedure relies on Computed Tomography - CT imaging as data source for the identification and modelling of the anatomy. Materialise Mimics was used as segmentation software to process the CT data. While its usefulness for the surgical needs was verified on a single clinical case (provided by the Careggi Hospital of Florence, Italy), the modelling procedure was tested twice, to produce a physical replica both ex-ante and ex-post surgical intervention. • The tools used for segmentation and generation of the printable model were customized to reduce modelling time for the specific type of desired model. • Detailed information on the use of modeling tools, not available in the literature, will be provided. • The procedure allows fabrication of a physical model representing the heart chambers in a short time.

Keywords: 3D printing , Left Ventricular Aneurysm , Method for the production of an anatomical replica of a human heart for surgical planning , Surgical planning

Additive Manufacturing technologies have opened new perspectives for the realization of tissue and organs substitutes. The main advantages come from the possibility of using the same technology to produce artificial or biological substitutes in a wide range of outer shapes and inner reticular architectures, which may pave the way to their use to produce personalized substitutes. Additive manufacturing technologies are based on layer-by-layer material fusion and deposition. As such, they have intrinsic limitations which may hinder the possibility to produce substitutes that meet the requirements for safe clinical use. As an example, discontinuities between layers may make the outer surface of a substitute significantly uneven, rough, and may even weaken the substitute mechanical properties in such an aggressive environment as the human body. Moreover, repeated thermal cycles (fusion and solidification) drastically limit the choice of materials which can be used. Finally, the outcome of the production technology is affected by many variables that it is not trivial to control to deliver the necessary quality and repeatability of the production process for medical applications. Indeed, the surface roughness of an implantable prosthesis or organ substitute is key to modulate cell adhesion and the susceptibility to chemical attack by body fluids. Structural strength is a mandatory requirement for load-bearing prostheses (e.g., orthopedic and dental prostheses). Materials for biomedical applications must not only be 3D printable, but also biocompatible and/or possibly have to promote cells growth and to prevent inflammatory reactions. The performance of artificial, bio artificial and tissue-engineered organs needs also to be certified and guaranteed, a rather difficult task to define for devices which may be unique, being tailored on the specific needs of the patient. In this paper, it will be discussed whether this technology is sufficiently mature to replace more traditional techniques or, alternatively, whether it should be limited to a restricted range of emergency applications until the existing relevant technological gaps are filled.

Keywords: 3D printing , additive manufaturing , artificial organs , clinical , corrosion , fatigue , prostheses , strength , surface , surgical guides , wear

Radiological examination of pulmonary nodules on CT involves the assessment of the nodules' size and morphology, a procedure usually performed manually. In recent years computer-assisted analysis of indeterminate lung nodules has been receiving increasing research attention as a potential means to improve the diagnosis, treatment and follow-up of patients with lung cancer. Computerised analysis relies on the extraction of objective, reproducible and standardised imaging features. In this context the aim of this work was to evaluate the correlation between nine IBSI-compliant morphological features and three manually-assigned radiological attributes – lobulation, sphericity and spiculation. Experimenting on 300 lung nodules from the open-access LIDC-IDRI dataset we found that the correlation between the computer-calculated features and the manually-assigned visual scores was at best moderate (Pearson's r between -0.61 and 0.59; Spearman's ρ between -0.59 and 0.56). We conclude that the morphological features investigated here have moderate ability to match/explain manually-annotated lobulation, sphericity and spiculation.

Keywords: Lung cancer , Morphological features , Pulmonary nodules , Radiomics

In the last years, the precision and personalized medicine is pushing the biomedical research efforts towards the direction of implant surgery requiring only 1-step approach: this goal has been achieved after the introduction of resorbable implants. The resorbable prosthetic support is indicated for temporary prosthetic applications, such as bone fractures fixation, or all those conditions usually treated with metal implants then removed with a second surgery, just after the healing of the bone defect. Biodegradable, bioactive and customizable implants for the treatment of bone fractures, both efficient in bearing the functional loads, and showing good biocompatibility and degradation properties matching the bone tissue healing, are still lacking. These premises have led to consider Magnesium (Mg) and its alloys as very promising candidates for the development of temporary, resorbable implants. However, the very high corrosion rate of Mg is the main problem, not yet solved. The material needs to be properly treated/coated, as well as manufactured, in order to design the most suitable duration of the temporary prosthesis permanence in situ. An innovative and interdisciplinary approach has been developed within the M.Era-Net ISIDE project and it is here briefly detailed with a special focus on the highlighted application fields.

Keywords: customade prostesis , Mg alloys , Reabsorbable implants

In recent years, 3D printed scaffolds have been proposed as promising alternative to the conventional cell culture techniques. Scaffolds, indeed, allow the development of a higher number of cellular connections along the three dimensions favoring the cell regeneration, which make them particularly suitable in case of implants for deteriorate bones in old age patients. Besides the characteristics of biocompatibility and biodegradability fundamental for the integration of the scaffolds with the human body, the inner morphology, the permeability as well as the porosity are parameters of paramount relevance in the design of 3D-printed scaffolds influencing the flow of the blood through the cells and, thus, their metabolic functions. In the present work the influence of the internal geometry of 3D-printed scaffolds on the blood flow was investigated. Five cylindrical scaffolds having different internal geometry and different porosity were fabricated using parametric design technique. Numerical analysis of the blood flow within the designed structures was conducted by using CFD tool.

Keywords: additive manufacturing , blood flow simulation , bone scaffolds , parametric design , porous metal

Benign and malignant lesions in tissues or organs can be detected by elastographic investigations in which pathological regions are spotted from local alterations of the stiffness. As is known, the shear modulus provides a measure of the stiffness of an elastic material. Based on the classical theory of linear elasticity, an elastogram yields estimations of the linear shear modulus from measurements of the speed of small-amplitude transverse waves propagating in the medium tested. In this paper, we show that the estimation of the shear modulus can be improved significantly by employing the fourth-order weakly nonlinear theory of elasticity (FOE), and indicate how the stiffness can be assessed more precisely with the use of FOE. We discuss also why FOE provides more reliable results than the fully nonlinear theory of elasticity. This article is part of the theme issue 'The Ogden model of rubber mechanics: Fifty years of impact on nonlinear elasticity'.

Keywords: elastography , nonlinear elasticity , shear modulus , strain-energy density functions , weakly nonlinear theory

The spine is the load-bearing structure of human beings and may present several disorders, with low back pain the most frequent problem during human life. Signs of a spine disorder or disease vary depending on the location and type of the spine condition. Therefore, we aim to develop a probabilistic atlas of the lumbar spine segment using statistical shape modeling (SSM) and then explore the variability of spine geometry using principal component analysis (PCA). Using computed tomography (CT), the human spine was reconstructed for 24 patients with spine disorders and then the mean shape was deformed upon specific boundaries (e.g., by (Formula presented.) or (Formula presented.) standard deviation). Results demonstrated that principal shape modes are associated with specific morphological features of the spine segment such as Cobb's angle, lordosis degree, spine width and height. The lumbar spine atlas here developed has evinced the potential of SSM to investigate the association between shape and morphological parameters, with the goal of developing new treatments for the management of patients with spine disorders.

Keywords: biomechanics , pathological lumbar spine segment , PCA , spinal column , SSM

Following an oncological resection or trauma it may be necessary to reconstruct the normal anatomical and functional mandible structures to ensure the effective and complete social reintegration of patients. In most surgical procedures, reconstruction of the mandibular shape and its occlusal relationship is performed through the free fibula flap using a surgical guide which allows the surgeon to easily identify the location and orientation of the cutting plane. In the present work, we present a Mixed Reality (MR)-based solution to support professionals in surgical guide positioning. The proposed solution, through the use of a Head-Mounted Display (HMD) such as that of the HoloLens 2, visualizes a 3D virtual model of the surgical guide, positioned over the patient's real fibula in the correct position as identified by the medical team before the procedure. The professional wearing the HMD is then assisted in positioning the real guide over the virtual one by our solution, which is capable of tracking the real guide during the whole process and computing its distance from the final position. The assessment results highlight that Mixed Reality is an eligible technology to support surgeons, combining the usability of the device with an improvement of the accuracy in fibula flap removal surgery.

Keywords: HoloLens 2 , mandibular reconstruction , maxillofacial surgery , mixed reality , surgical guide

The following document outlines the design process of a haptic feedback glove. The aim of this project is to give the user a haptic feedback once they are in contact with an object in a virtual interactive 3D space. In order to induce a haptic feedback, Unity3D is used to simulate the 3D virtual space, Leap motion is used in order to track the hands of the user and map them on the 3D virtual space. Finally, the signal from Unity is sent to Arduino which is able to produce the signal to initiate the vibration motors and led lights. The purpose of this technology is to help people with reduced motor ability, to perform physiotherapy exercises while playing an interactive game that involves haptic feedback.

Keywords: Arduino , Haptic feedback , Leap motion and rehabilitation , Sharebot , Unity3D

The study of the spine range of motion under given external load has been the object of many studies in literature, finalised to a better understanding of the spine biomechanics, its physiology, eventual pathologic conditions and possible rehabilitation strategies. However, the huge amount of experimental work performed so far cannot be straightforwardly analysed due to significant differences among loading set-ups. This work performs a meta-analysis of various boundary conditions in literature, focusing on the flexion/extension behaviour of the lumbar spine. The comparison among range of motions is performed virtually through a validated multibody model. Results clearly illustrated the effect of various boundary conditions which can be met in literature, so justifying differences of biomechanical behaviours reported by authors implementing different set-up: for example, a higher value of the follower load can indeed result in a stiffer behaviour; the application of force producing spurious moments results in an apparently more deformable behaviour, however the respective effects change at various segments along the spine due to its natural curvature. These outcomes are reported not only in qualitative, but also in quantitative terms. The numerical approach here followed to perform the meta-analysis is original and it proved to be effective thanks to the bypass of the natural variability among specimens which might completely or partially hinder the effect of some boundary conditions. In addition, it can provide very complete information since the behaviour of each functional spinal unit can be recorded. On the whole, the work provided an extensive review of lumbar spine loading in flexion/extension.

Keywords: Biomechanics , Follower load , Lumbar spine , Mechanical tests , Multibody , ROM

Titanium and its alloys are widely employed in commercial dental devices. Because the surface morphology and chemical composition of Ti-based dental implants play a relevant role in osseointegration, three different commercial threaded implants have been investigated by scanning electron microscopy and X-ray photoelectron spectroscopy (XPS). The Implants A and C were made of pure Ti whereas the Implant B was made of Ti6Al4V alloy. Obtained results evidenced the common features and differences due to specific process parameters used in the treatments of mordanting and sandblasting for surface roughening. Implant A exhibits a uniform surface covered by very small dimples of about 1–2 μm. The surface of Implant B is not homogeneous: The thread tops present an irregular morphology (dimples size >10 μm) while finer dimples (about 1 μm) are observed along the thread flanks and valleys. Implant C shows an irregular morphology with dimples of different sizes and shapes distributed on thread tops, flanks, and valleys. XPS analyses revealed the presence of metal oxides: TiO2 in all the implants; Al2O3 and V2O5 only in the implant B. Moreover, these results demonstrated that Mg2SiO4 is present on the surface of Implant A, probably due to a specific preparation process. Obtained results have been discussed on the basis of the factors promoting the osseointegration.

Keywords: dental implants , SEM , surface morphology , Ti6Al4V , titanium , XPS