Methods for medical applications

Shoulder disorders are very common in the middle-aged population, due to several causes. The traditional diagnosis relies on the knowledge and the experience of the physician but a clinical misinterpretation in this early phase can have serious consequences for the patient's health. The aim of this study is to investigate morphologicalshoulder parameters, as indicators of healthy or pathological conditions. In this way, it is possible to generate a quantitative report, based on measurements. It can be exploited as a medical support tool for physicians to either confirm the diagnosis, or to raise reasonable doubts, as far as the results differed. However, not all the shoulder disorders can be identified through this approach. Magnetic Resonance and Computed Tomography images of pathological shoulders have been employed for the study. The predefined morphological parameters have been measured on 2D medical images as well as from 3D reconstructed virtual model. Critical Shoulder Angle has been identified as the most significant parameter. It is well known that it is affected by Glenoid Inclination, Lateral Acromial Extension and Acromial Height. However, the contribution of each factor is not clear. Hence, a statistical analysis has been performed to understand how its sub-parameters influence it.

Keywords: Critical Shoulder Angle , Morphological Analysis , Patient Assessment , Shoulder Disorders

Auxetic materials can be exploited for coupling different types of tissues. Herein, we designed a material where the microorganism metabolic activity yields the formation of buckled/collapsed bubbles within gelling silicone cylinders thus providing auxetic properties. The finite element model of such hollow auxetic cylinders demonstrated the tubular structure to promote worm-like peristalsis. In this scenario, the described hybrid auxetic structures may be applied to the longitudinal intestinal lengthening and tailoring procedure to promote enteral autonomy in short bowel syndrome. The presented material and analytical design synergistic approach offer a pioneering step for the clinical translation of hybrid auxetic materials.

Keywords: auxetic materials , graphene , intestinal failure , mechanical modeling , reconstructive surgical procedures , short bowel syndrome

Fractures to the orbital walls and floor must be appropriately managed to avoid severe conditions. This results in particularly challenging anatomical reconstructions. The main issues are the implant's proper shaping, placement, and orientation onto the eye socket. A new, customized implant-shaping mould has already been developed to shape patient-specific implants. However, it still does not address the implant positioning in the fractured orbital cavity. This present research aims to design, develop, and assess an innovative implant positioner to be used with the optimized version of the aforementioned implant-shaping mould. The new medical device was designed to be used with titanium meshes and deantigenated bone implants. It is easy to use, has a low cost, and is reusable several times. It is composed of (1) two coupled and hinged handles that allow the grasping of the implant, and (2) the positioner itself that permits proper implant placement and orientation. Selective laser sintering was used to print the mould and the new device in polyamide. Promising results for implant shaping, positioning, and orientation accuracy were obtained. An accuracy of 0.1 mm and 1.3 mm was, respectively, achieved for the implant shape and its placement in the mediolateral direction. The mean malrotation angle around the orbital rim was about 6°.

[No abstract available]

Purpose: We evaluate the ability of Artificial Intelligence with automatic classification methods applied to semi-quantitative data from brain 18F-FDG PET/CT to improve the differential diagnosis between Alzheimer Disease (AD) and Mild Cognitive Impairment (MCI). Procedures: We retrospectively analyzed a total of 150 consecutive patients who underwent diagnostic evaluation for suspected AD (n = 67) or MCI (n = 83). All patients received brain 18F-FDG PET/CT according to the international guidelines, and images were analyzed both Qualitatively (QL) and Quantitatively (QN), the latter by a fully automated post-processing software that produced a z score metabolic map of 25 anatomically different cortical regions. A subset of n = 122 cases with a confirmed diagnosis of AD (n = 53) or MDI (n = 69) by 18–24-month clinical follow-up was finally included in the study. Univariate analysis and three automated classification models (classification tree –ClT-, ridge classifier –RC- and linear Support Vector Machine –lSVM-) were considered to estimate the ability of the z scores to discriminate between AD and MCI cases in. Results: The univariate analysis returned 14 areas where the z scores were significantly different between AD and MCI groups, and the classification accuracy ranged between 74.59% and 76.23%, with ClT and RC providing the best results. The best classification strategy consisted of one single split with a cut-off value of ≈ −2.0 on the z score from temporal lateral left area: cases below this threshold were classified as AD and those above the threshold as MCI. Conclusions: Our findings confirm the usefulness of brain 18F-FDG PET/CT QL and QN analyses in differentiating AD from MCI. Moreover, the combined use of automated classifications models can improve the diagnostic process since its use allows identification of a specific hypometabolic area involved in AD cases in respect to MCI. This data improves the traditional 18F-FDG PET/CT image interpretation and the diagnostic assessment of cognitive disorders.

Keywords: Alzheimer disease , artificial intelligence , automatic classification , brain 18F-FDG PET/CT , mild cognitive impairment

Since every structure in the human body can vary, customization is important to choose the most appropriate medical option according to the patient. Total knee arthroplasty (TKA) is a surgical procedure for the knee replacement that has a high rate of patient's dissatisfaction. Indeed, conventional prostheses are based on anthropometric data that accommodate common knees. However, mismatch can occur due to anatomical variations among the individuals. Thanks to the advances in imaging techniques and 3D modeling, it is possible to create customized knee implants starting from medical images. In this context, the present research proposes a methodology to design a customized knee implant taking into account clinical (e.g., prosthesis alignment and surgical cuts) and technical parameters (e.g., materials) that have a direct impact on TKA performance and patient's satisfaction. Changing these parameters, different scenarios have been modeled and simulated to understand the most suitable combination. Finite element analysis (FEA) has been employed to simulate and compare the proposed customized models, changing the different clinical and technical parameters. Stress induced by different combinations of the parameters has been evaluated to choose the optimal solution among the eight proposed scenarios. The optimum is reached with a physiological alignment, with six femoral facets and the ultra-high molecular weight polyethylene (UHMWPE) tibial insert. The implant design maintains the natural joint line and allows preserving more bone. The material is the parameter that mostly influences the stress distribution.

Keywords: computer aided design , computer aided engineering , customized knee implant , femoral component optimization , finite element analysis , knowledge engineering , patient-specific knee prosthesis , total knee arthroplasty , virtual prototyping

Objectives: This study aims to evaluate the acceptability of Cinematic VR technology as a novel therapeutic approach supporting Social Skills Training (SST) rehabilitation interventions among patients with schizophrenia. Materials and Methods: We developed an innovative cinematic VR-based platform as a support system for SST rehabilitation of independent living skills and evaluated its acceptance among psychiatric patients in terms of usability, user experience, and use performance. Ten voluntary participants were enrolled in the study. The study inclusion criteria consisted of age 18-65 years, lack of moderate and severe intellectual disability, no substance use disorder, and schizophrenia spectrum disorder pathology according to DSM V. We administered post treatment questionnaires and developed the platform to capture relevant data automatically. Results: Patients rated usability and user experience from good to excellent. We also observed an improvement in the use performance. Conclusions: Cinematic Virtual Reality based applications showed good acceptability among patients with schizophrenia. This result supports further efforts in evaluating its effectiveness as a novel therapeutic approach supporting SST rehabilitation interventions.

Keywords: Cinematic virtual reality , Schizophrenia rehabilitation , Social skills training , Task performance , Usability , User experience

Drill tool positioning in dental implantology is a challenging task requiring 5DOF precision as the rotation around the tool axis is not influential. This work improves the quasi-static visual elements of the state-of-the-art with a novel Augmented Collimation Widget (ACW), an interactive tool of position and angle error visualization based on the gestalt reification, the human ability to group geometric elements. The user can seek in a quick, pre-attentive way the collimation of five (three positional and two rotational) error component widgets (ECWs), taking advantage of three key aspects: component separation and reification, error visual amplification, and dynamic hiding of the collimated components. We compared the ACW with the golden standard in a within-subjects (N=30) user test using 32 implant targets, measuring the time, error, and usability. ACW performed significantly better in positional (+19%) and angular (+47%) precision accuracy and with less mental demand (-6%) and frustration (-13%), but with an expected increase in task time (+59%) and physical demand (+64%). The interview indicated the ACW as the main preference and aesthetically more pleasant than GSW, candidating it as the new golden standard for implantology, but also for other applications where 5DOF positioning is key.

Keywords: Augmented Reality , augmented tool , dental implantology , gestalt principles , spatial orientation , visualization design

Complex deformities of lower limbs are frequent in children with genetic or metabolic skeletal disorders. Early correction is frequently required, but it is technically difficult and burdened by complications and recurrence. Herein, we described the case of a 7-year-old girl affected by severe bilateral genu varum due to spondyloepiphyseal dysplasia. The patient was treated by patient-specific osteotomies and customized structural wedge allograft using Virtual Surgical Planning (VSP) and 3D-printed patient-specific instrumentation (PSI). The entire process was performed through an in-hospital 3D-printing Point-of-Care (POC). VSP and 3D-printing applied to pediatric orthopedic surgery may allow personalization of corrective osteotomies and customization of structural allografts by using low-cost in-hospital POC. However, optimal and definitive alignment is rarely achieved in such severe deformities in growing skeleton through a single operation.

Keywords: 3D-printing , cutting guide , in-hospital , osteotomy , patient-specific instruments , pediatric , point-of-care , spondyloepiphyseal dysplasia , structural allograft , VSP

Purpose: The purpose of this study is to describe the design and validation of a three-dimensional (3D)-printed phantom of a uterus to support the development of uterine balloon tamponade devices conceived to stop post-partum haemorrhages (PPHs). Design/methodology/approach: The phantom 3D model is generated by analysing the main requirements for validating uterine balloon tamponade devices. A modular approach is implemented to guarantee that the phantom allows testing these devices under multiple working conditions. Once finalised the design, the phantom effectiveness is validated experimentally. Findings: The modular phantom allows performing the required measurements for testing the performance of devices designed to stop PPH. Social implications: PPH is the leading obstetric cause of maternal death worldwide, mainly in low- and middle-income countries. The proposed phantom could speed up and optimise the design and validation of devices for PPH treatment, reducing the maternal mortality ratio. Originality/value: To the best of the authors' knowledge, the 3D-printed phantom represents the first example of a modular, flexible and transparent uterus model. It can be used to validate and perform usability tests of medical devices.

Keywords: 3D printing , Design for additive manufacturing , Device validation , Phantom , Post-partum haemorrhage

In this paper, the problem of robotic rehabilitation of upper limbs is addressed by focusing attention on the control of a standard collaborative robot for those training activities that can be performed with the aid of an end-effector type system. In particular, a novel admittance control, that constrains the motion of the robot along a prescribed path without imposing a specific time law along it, has been devised. The proposed approach exploits the features of the arc-length parameterization of a generic curve to obtain a simple control formulation able to guide the patient in both a passive or an active way, with the possibility of supporting the execution of the task with an additional force or opposing the motion with a braking force. Being the method independent from the particular curve considered for the constraint specification, it allows an intuitive definition of the task to be performed via Programming by Demonstration. Experimental results show the effectiveness of the proposed approach.

Keywords: Admittance control , Guidance virtual fixtures , Human-robot interaction , Rehabilitation

Virtual Reality (VR) opens new frontiers in the rehabilitation field. Low-cost head mounted displays and motion capture systems are available and easily integrated in consumer technologies, such as laptops, smartphones, and tablets. The main limit of VR is related to its acceptance because the technologies are usually considered too complex for patients' daily rehabilitation. Furthermore, available VR hardware solutions are usually designed for generic categories of users and there is a considerable margin to specific pathologies or patients. This chapter presents the development of VR platforms for both cognitive and motor skills rehabilitation starting from physicians' requirements and usability issues. Three VR applications are described: a platform for cognitive rehabilitation of patients with severe memory loss, an application to test the level of extra-personal neglect, and a web platform for hand motor skill rehabilitation.

Keywords: Cognitive rehabilitation , Motor skills rehabilitation , Tele-rehabilitation , User-centered design , Virtual reality

The definition of an innovative category of implantable devices, characterized not only by a fully customization but also by improved osteoconductive and functionalized bioactive surfaces, needs to be supported by a systematic approach. In the present work, a new human-machine interface based on the Mixed Reality (MR) is proposed and focused on the implantation of a fully customized prosthesis. By means of an informal and exploratory focus group (i.e., without using a structured questionnaire), the limitations belonging to the current procedure were highlighted and a first list of user needs was subsequently defined. The MR interface was then considered to be the most suitable solution to match the gathered requirements. However, the doctors proposed also to develop a desktop interface for a finer and easier manipulation of 3D models. The proposed MR application offers several advantages from the possibility to display 3D anatomical structures and 3D models of custom prostheses in an immersive environment to the optimized communication and data exchange among the players (medical staff, doctors and engineers). A mock-up of the MR applications is presented in this work to show the results of the design stage, before the deployment of the application.

Keywords: Collaborative Network , Fully Custom Implants , Immersive Environment , Mixed Reality

Three-dimensional printed models have been increasingly used in many fields of medicine. The most common benefits include a better understanding of anatomical details, an improved communication between clinicians and patients, a more accurate planning of treatments, and new opportunities for procedural training. In the cardiovascular field, this technology has contributed to improve the management of complex cases, in particular congenital heart disease, by fostering personalized preprocedural planning and increasing medical trainees' confidence. Cardiovascular structures, however, are extremely challenging to replicate using materials compatible with current 3D printing technologies. Hence, patient-specific computational models, generated from the same set of medical images as printed ones, can be combined to 3D printing technology to simulate different conditions and identify the optimal treatment for each specific patient. A further step forward is represented by the integration of advanced visualization techniques like augmented and virtual reality, to close still existing loopholes. In this chapter, we review the current possibilities associated with the use of patient-specific models, in the context of cardiovascular applications.

Keywords: 3D printing , cardiovascular models , computational fluid dynamics , finite element analyses , Patient-specific models , segmentation , validation

Objective: The aim of this study was to evaluate the influence of three different dental implant neck geometries, under a combined compressive/shear load using finite element analysis (FEA). The implant neck was positioned in D2 quality bone at the crestal level or 2 mm below. Methods: One dental implant (4.2 × 9 mm) was digitized by reverse engineering techniques using micro CT and imported into Computer Aided Design (CAD) software. Non-uniform rational B-spline surfaces were reconstructed, generating a 3D volumetric model similar to the digitized implant. Three different models were generated with different implant neck configurations, namely 0°, 10° and 20°. D2 quality bone, composed of cortical and trabecular structure, was modeled using data from CT scans. The implants were included in the bone model using a Boolean operation. Two different fixture insertion depths were simulated for each implant: 2 mm below the crestal bone and exactly at the level of the crestal bone. The obtained models were imported to FEA software in STEP format. Von Mises equivalent strains were analyzed for the peri-implant D2 bone type, considering the magnitude and volume of the affected surrounding cortical and trabecular bone. The highest strain values in both cortical and trabecular tissue at the peri-implant bone interface were extracted and compared. Results: All implant models were able to distribute the load at the bone-implant contact (BIC) with a similar strain pattern between the models. At the cervical region, however, differences were observed: the models with 10° and 20° implant neck configurations (Model B and C), showed a lower strain magnitude when compared to the straight neck (Model A). These values were significantly lower when the implants were situated at crestal bone levels. In the apical area, no differences in strain values were observed. Significance: The implant neck configuration influenced the strain distribution and magnitude in the cortical bone and cancellous bone tissues. To reduce the strain values and improve the load dissipation in the bone tissue, implants with 10° and 20 neck configuration should be preferred instead of straight implant platforms.

Keywords: Dental implants , Finite element analysis , Implant design , Strain distribution

In the article titled “Design of Additively Manufactured Lattice Structures for Biomedical Applications” [1], there was an error in the author's name, where “Sverio Maietta” should be corrected to “Saverio Maietta.” e corrected author name is shown in the author group above.

Background and objective: Because of the three-dimensional distribution of morphological features of human vertebrae and the whole spine, in recent years, to make more precise diagnoses and to design optimized surgical procedures, new protocols have been proposed based on analysing their three-dimensional (3D) models. In the related literature, processes of segmentation and morphological features recognition are essentially performed by a skilled operator that selects the interesting areas. So, being affected by the preparation and experience of the operator, this produces an evaluation that is poorly reproducible and repeatable for the uncertainties of a typical manual measurement process. Methods: To overcome this limitation, in this paper a new automatic method is proposed for feature segmentation and recognition of human vertebrae. The proposed computer-based method, starting from 3D high density discretized models of thoracic and lumbar vertebrae, automatically performs both the semantic and geometric segmentation of their morphological features. The segmentation and recognition rules codify some important definitions used in the traditional manual method, considering all the vertebra morphology information that is invariant inter-subject. Results: The automatic method proposed here is verified by analysing many real vertebrae, both acquired using a 3D scanner and coming from Computerized Tomography (CT) scans. The obtained results are critically discussed and compared with the traditional manual methods for vertebra analysis. The method has proven to be robust and reliable in the segmentation and recognition of morphological features of vertebrae. Furthermore, the proposed automatic method avoids the blurring of quantitative parameters get from vertebrae, resulting from poor repeatability and reproducibility of manual methods used in the state-of-the-art. Conclusions: Starting from the automatic segmentation and recognition here proposed, it is possible to automatically calculate the parameters of thoracic or lumbar vertebrae used in archaeology, medicine, or biomechanics or define their new ones.

Keywords: 3D medical image analysis , Computer methods for vertebra analysis , Shape segmentation , Thoracic and lumbar vertebrae , Three-dimensional measurement

Evidence regarding the effect of the onlay preparation design for different CAD/CAM restorative materials considering the preservation of cusps is lacking. Molars were 3D-modeled in four preparation designs for onlay restoration: Traditional design with functional cusp coverage (TFC), non-retentive design with functional cusp coverage (NFC), traditional design with non-functional cusp coverage (TNFC) and non-retentive design with non-functional cusp coverage (NNFC). The restorations were simulated with two CAD/CAM restorative materials: LD—lithium disilicate (IPS e.max CAD) and RC—resin composite (GrandioBloc). A 100 N axial load was applied to the occlusal surface, simulating the centric contact point. Von Mises (VM) and maximum principal (Pmax) stress were evaluated for restorations, cement layer and dental substrate. The non-retentive preparation design reduced the stress concentration in the tooth structure in comparison to the conventional retentive design. For LD onlays, the stress distribution on the restoration intaglio surface showed that the preparation design, as well as the prepared cusp, influenced the stress magnitude. The non-retentive preparation design provided better load distribution in both restorative materials and more advantageous for molar structure. The resin composite restoration on thenon-functional cusp is recommended when the functional cusp is preserved in order to associate conservative dentistry and low-stress magnitude.

Keywords: Biomechanics , Dental materials , Finite element analysis , Prosthodontics

The aim of the present study was to investigate the effect of shrinking and no shrinking dental filling materials combination in posterior restorations under the combined effects of polymerization shrinkage and occlusal load by means of 3D Finite Elements Analysis. Six computer-generated and restored class I or class II cavities models of a lower molar were designed in the CAD software and evaluated according to the cavity and restorative procedure. Different shrinking and no shrinking adhesive materials combination with diverse Young's modulus were considered. A food bolus was modeled on the occlusal surface replicating the chewing load using static linear analyses Polymerization shrinkage was simulated for the shrinking different restorative materials. The maximum principal stress was selected as analysis criteria. All models exhibited higher stresses along the dentine restoration interfaces with different magnitude and a similar stress trend along enamel restoration interface. Stress values up to 22 MPa and 19 MPa were recorded in the enamel and restoration, respectively. The use of elastic not shrinking material layer in combination with bulk fill composite reduced the stress magnitude in dentine and enamel to replace dental tissues. Class I and class II posterior cavities adhesively restored with shrinking filling material's combination showed the most unfavorable stress concentrations and the multilayer technique is a promising restorative alternative in posterior adhesive restorations when deep dentin and enamel volumes are missing.

Keywords: Dental materials , Dental restoration failure , Finite element analysis , Shrinkage polymerization

Background and objective: The aim of the present study was to review the literature concerning the analysis of periprosthetic bone remodeling through finite element (FE) simulation. Methods: A systematic review was conducted on 9 databases, taking into account a ten-year time period (from 2009 until 2020). The inclusion criteria were: articles published in English, publication date after 2009, full text articles, articles containing the keywords both in the abstract and in the title. The articles were classified through the following parameters: dimensionality of the simulation, modelling of the bone-prosthesis interface, output parameters, type of simulated prosthesis, bone remodeling algorithm. Results: Sixty-seven articles were included in the study. Femur and tooth were the most evaluated bone segment (respectively 41.8% and 29.9%). The 55.2% of the evaluated articles used a bonded bone-prosthesis interface, 73% used 3D simulations, 67.2% of the articles (45 articles) evaluate the bone remodeling by the bone density variation. At last, 59.7% of the articles employed algorithms based on a specific remodeling function. Conclusions: Increasing interest in the bone remodeling FE analysis in different bone segments emerged from the review, and heterogeneous solutions were adopted. An optimal balance between computational cost and accuracy is needed to accurately simulate the bone remodeling phenomenon in the post-operative period.

Keywords: Biological processes , Bone remodeling , Computational analysis , FE simulations , Prosthesis , Systematic review