Methods for medical applications

Osseointegrated implant is a promising solution for limb amputations, but its widespread use is limited by risks such as bone resorption, infections, and strict patient requirements. Typically, the bone and prosthesis are coupled using a press-fit condition, providing short-term stability, or primary stability (PS), which leads to bone in-growth and long-term stability, or secondary stability (SS). However, the greater stiffness of the implant compared to the bone is a concern for SS. Currently, osseointegrated implants are commercially available only in fixed configurations, with a limited use of customization. This study aims to compare the contact effectiveness of three press-fitted intramedullary stems for femoral amputations, developed using three designs (straight, standard curvature, and patient-specific curvature). Moreover, a novel implant design methodology is reported, such is an easy way to develop a patient-specific design. The von Mises stress distribution at the bone-implant interface was analyzed. The study uses CAD models of a femur acquired through CT scans. A FEA was conducted to evaluate the elastic behavior of the bone when the implant is press-fitted with an interference of 0.1 mm. The outcomes show how the patient-specific implant result in a more physiological distribution of the load in the bone. This study could be used as a starting point for further studies on primary and secondary stabilities.

Keywords: 3D Modelling , Finite Element Model , Osseointegration , Patient-Specific Design , Transfemoral Implant

The Reverse Total Shoulder Arthroplasty (RTSA) is a complex surgical procedure also due to the difficulty in correctly positioning all the components of the prosthesis. Malpositioning of the prosthesis, in fact, can lead to various complications such as scapular notching, early mobilization, instability and reducing of the range of movement (ROM). Preoperative planning with 3D imaging and patient specific instruments can be very useful tools to help surgeon in selecting the optimal position of implant components. Aim of this work is to develop a procedure based on a fully parametric CAD system that simulates the shoulder joint to identify the optimal positioning of the humeral and glenoid components of the prosthesis. In particular, the proposed system allows to find the optimal cutting angles of the humerus head and the glenoid cavity so to best fit the patient's bone structure and the prosthesis components and, consequently, to improve the range of movement. The system allows to create, in a semi-automatic way, CAD assembly models composed of the patient shoulder bones and different reverse shoulder prostheses. For each assembly different positions of the components of the prosthesis can be evaluated and various scenarios of movements can be simulated. In this way it is possible to identify the optimal positioning of the prosthesis for each patient in the preoperative stage. The proposed procedure has been tested with two types of prosthesis and two patients. Obtained results demonstrated that an optimal positioning of prosthesis an improve ROM up to 27%.

Keywords: CAD , Preoperative planning , Reverse engineering , Reverse total shoulder arthroplasty

The purpose of the study was to evaluate the performance of radiomics analysis of MR images for the detection of prostate cancer. The radiomics analysis was conducted using axial T2-weighted images from 49 prostate cancers. The study employs a sophisticated hybrid descriptive-inferential method for the meticulous selection and reduction of features, followed by discriminant analysis to construct a robust predictive model. Among 71 radiomics features, original_glrlm_ShortRunLowGrayLevelEmphasis demonstrated exemplary performance in differentiating between the whole prostate gland and prostate cancer. It had an AUROC of 68.46 (95% CI 0.544 – 0.824; p = 0.022), sensitivity of 76.25%, specificity of 73.15%, and accuracy of 71.02%. Radiomic analysis of T2 weighted MR images was demonstrated to have clinical application in prostate cancer detection, paving the way for improved diagnostic procedures and tailor-made treatment plans for prostate cancer patients.

Keywords: Magnetic Resonance Imaging , Prostate Cancer , Radiomics , Texture Analysis

This paper proposes a methodology to compare the trajectories from different articulators - both physical and digital - during lateral and protusive movements. In the case of digital articulators, the articulated models are digitally moved and exported in position; in the case of mechanical articulators, the models are locked into position and 3D scanned. The digital models in position, both digital and scanned, are aligned to a common reference system and a maxilla-based reference system is tracked. The trajectories are defined as interpolating splines through the maxilla-based reference system origins. A Gerber mechanical articulator and an “Artex CR adjustable” virtual articulator were compared. The repeatability of the mechanical trajectory is found to be less than 184 microns. The resting position of the two articulators is found significantly different meaning that a bias is introduced by the operator in the analogic protocol. The trajectories have significantly different shapes as expected coming from two different articulator models. The proposed methodology proved to be a valid means to compare different articulators.

Keywords: 3D Scanners , Articulators , Complete Dentures , Trajectory Reconstruction

Protein–protein interaction occurs on surface patches with some degree of complementary geometric and chemical features. Building on this understanding, this study endeavors to characterize the spike protein of the SARS-CoV-2 virus at the morphological and geometrical levels in its Alpha, Delta, and Omicron variants. In particular, the affinity between different SARS-CoV-2 spike proteins and the ACE2 receptor present on the membrane of the human respiratory system cells is investigated. To achieve an adequate degree of geometrical accuracy, the 3D depth maps of the proteins in exam are filtered by developing an ad-hoc convolutional filter with a kernel implemented as a sphere of varying radius, simulating a ball rolling on the surface (similar to the 'rolling ball' filter). This ball ideally models a hypothetical molecule that could interface with the protein and is inspired by the geometric approach to macromolecule–ligand interactions proposed by Kuntz et al. in 1982. The aim is to mitigate the imperfections and to obtain a smoother surface that could be studied from a geometrical perspective for binding purposes. A set of geometric descriptors, borrowed from the 3D face analysis context is then mapped point-by-point onto protein depth maps. Following a feature extraction phase inspired by Histogram of Oriented Gradients and Local Binary Patterns, the final histogram features are used as input for a Support Vector Machine classifier to automatically classify the proteins according to their surface affinity, where a similarity in shape is observed between ACE2 and the spike protein of the SARS-CoV-2 Omicron variant. Finally, Root Mean Square Error analysis is used to quantify the geometrical affinity between the ACE2 receptor and the respective Receptor Binding Domains of the three SARS-CoV-2 variants, culminating in a geometrical explanation for the higher contagiousness of Omicron relative to the other variants under study.

The use of CAD and 3D printing of surgical guides (SGs) for osteotomies is a widely developed practice in orthopaedic surgery, and particularly in maxillo-facial interventions, but validation studies rarely occur in literature. The present study defines a methodology to validate SGs dimensionally and mechanically through geometrical analysis, tensile testing, contact simulations, and abrasion testing. Distortions between the 3D printed SGs and the CAD model are quantified and an average deviation error for each production process step is obtained. Mechanical analysis identifies a way of applying the load on the SG to measure their equivalent linear stiffness (N/mm), maximum displacement (mm) and corresponding tolerable load (N) by varying some dimensional parameters. The stress state was assessed by finite element method (FEM) analysis, then the numerical results were compared with experimental ones using tensile tests: stiffness, maximum displacement and the corresponding loads were evaluated. The distribution of contact pressure on soft tissues was obtained numerically by FEM analysis. Finally, an ad hoc machine has been specially built to engrave discoidal specimens with typical operating room conditions. The methodology has been validated using 11 SG fibular and mandibular specimens and reporting the obtained results of each procedure step.

Keywords: CAD , Cutting guides , FEM , Maxillo-facial surgery , Surgical guides

In orthopedic surgery and maxillofacial there is a growing use of augmented reality (AR) as a technology to increase the visual perception of the surgeon in the operating room. The objective of this review is to analyze the state of the art in the use of AR for osteotomies, highlighting the advantages and the most-known open issues to be addressed in the future research. Scopus, Web of Science, Pubmed and IEEE Xplore databases have been explored with a keyword search, setting the time limits from January 2017 to January 2023, inclusive. Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines has been used in this review, focusing on anatomical districts, real-virtual environment interaction, advantaged and limitations of existing AR-based applications. 49 articles met the inclusion criteria and have been selected in the final analysis. For the sake of clarity, works have been grouped according to the anatomical district, but also the real-virtual environment interaction methodology was reported, as well as information regarding accuracy assessment. A Quality Function Deployment (QFD) has been used to assess the AR-based solutions with regards to the more traditional freehand (FH) and Patient Specific Template (PST) approaches. Finally, some suggestions to foster the AR-based solution adoption in osteotomies treatment have been drawn, considering the highlighted advantages and limitations of this technology. The AR resulted to meet the surgeons' needs more than other traditional approaches. Among the emerged advantages, AR can lead to a better surgical field accessibility, more flexible solutions and lower the management effort. Nonetheless, future research should address some well-known issues, among which the calibration time, the robustness of the tracking, and the HMDs discomfort.

Keywords: Augmented reality , Cutting guides , Maxillofacial surgery , Mixed reality , Orthopedic surgery , Osteotomies , Patient specific templates , Surgical guides

Background and objective: Many diseases of the spine require surgical treatments that are currently performed based on the experience of the surgeon. The basis of this study is to deliver an automatic and patient-specific algorithm able to come to the aid of the surgeons in pedicle arthrodesis operations, by finding the optimal direction of the screw insertion, the maximum screw diameter and the maximum screw length. Results: The paper introduce an algorithm based on the reconstructed geometry of a vertebra by 3D-scan that is able to identify the best introduction direction for screw and to select, from commercial and/or personalised databases, the best screws in order to maximize the occupation of the bone while not intersecting each other and not going through the walls of the pedicle and the bounds of the vertebral body. In fact, for pedicle arthrodesis surgery, the incorrect positioning of the screws may cause operating failures, an increase in the overall duration of surgery and, therefore, more harmful, real-time X-ray checks. In case of not availability on market, the algorithm also suggests parameters for designing and manufacturing an ‘ad hoc' solution. The algorithm has been tested on 6 vertebras extracted by a medical database. Furthermore, the algorithm is based on a procedure through which the surgeon can freely choose the entering point of the screw (based on his/her own experience and will). A real patient vertebra has been processed with almost 400 different entering point, always giving a feedback on the possibility to use the entering point (in case of unavailability of a good trajectory) and on the individuation of the right trajectory and the choose of the better screws. Conclusions: In very recent bibliography, several papers deal with procedure to screw' trajectory planning in arthrodesis surgery by using Computer Aided surgery systems, and some of them used also modern methodologies (KBE, AI, Deep learning, etc.) methods for planning the surgery as better as possible. Nevertheless, no methodologies or algorithm have been still realized to plan the trajectory and choose the perfect fitting screws on the basis of the patient-specific vertebra. This paper represents a wind of novelty in this field and allow surgeons to use the proposed algorithm for planning their surgeries. Finally, it allows also the easy creation of a customized surgical template, characterized by two cylindrical guides that follow a correct trajectory previously calculated by means of that automatic algorithm generated on the basis of a vertebra CAD model for a specific patient. The surgeon will be able to set the template (drilling guides) on the patient's vertebra and safely apply the screws.

Keywords: Neurosurgery , Optimal insertion direction , Pedicle arthrodesis , Spine surgery , Standard screw , Surgical planning , Surgical Template

Objectives: This study aimed to investigate the biocompatibility, osteogenic and antibacterial activity of biomedical devices based on Magnesium (Mg) Alloys manufactured by Superplastic Forming process (SPF) and subjected to Hydrothermal (HT) and Sol-Gel Treatment (Sol-Gel). Methods: Mg-SPF devices subjected to Hydrothermal (Mg-SPF+HT) and Sol-Gel Treatment (Mg-SPF+Sol-Gel) were investigated. The biocompatibility of Mg-SPF+Sol-Gel and Mg-SPF+HT devices was observed by indirect and direct cytotoxicity assays, whereas the colonization of sample surfaces was assessed by confocal microscopy. qRT-PCR analysis and microbial growth curve analyses were employed to evaluate the osteogenic and antibacterial activity of both SPF-Mg treated devices, respectively. Results: Mg-SPF+HT and Mg-SPF+Sol-Gel showed a high degree of biocompatibility. Analysis of mRNA expression of osteogenic genes in cells cultured on Mg-treated devices revealed a significant upregulation of the expression levels of BMP2 and Runx-2. Furthermore, the bacterial growth in strains developed in contact with both the Mg-SPF+HT and Mg-SPF+Sol-Gel devices was lower than that observed in the control. Significance: Hydrothermal and Sol-Gel Treatments of Mg alloys obtained through the SPF process demonstrated bioactive, osteogenic and antibacterial activity, offering a promising alternative to conventional Mg-based devices. The obtained Mg-based materials may have the potential to enhance the tunability of temporary devices in maxillary reconstruction, eliminating the need for second surgeries, and ensuring a good bone reconstruction and a reduced implant failure rate due to bacterial infections.

Keywords: Antibacterial materials , Bone tissue engineering , Metallic biomaterials , Mg alloys , Resorbable implants

Polyether-ether-2-ketone (PEKK) is a high-performance thermoplastic polymer used in various fields, from aerospace to medical applications, due to its exceptional mechanical and thermal properties. Nonetheless, the mechanical behavior of 3D-printed PEKK still deserves to be more thoroughly investigated, especially in view of its production by 3D printing, where mechanical properties measured at different scales are likely to be correlated to one another and to all play a major role in determining biomechanical properties, which include mechanical strength on one side and osteointegration ability on the other side. This work explores the mechanical behavior of 3D-printed PEKK through a multiscale approach, having performed both nanoindentation tests and standard tensile and compression tests, where a detailed view of strain distribution was achieved through Digital Image Correlation (DIC) techniques. Furthermore, for specimens tested up to failure, their fractured surfaces were analyzed through Scanning Electron Microscopy (SEM) to clearly outline fracture modes. Additionally, the internal structure of 3D-printed PEKK was explored through Computed Tomography (CT) imaging, providing a three-dimensional view of the internal structure and the presence of voids and other imperfections. Finally, surface morphology was analyzed through confocal microscopy. The multiscale approach adopted in the present work offers information about the global and local behavior of the PEKK, also assessing its material properties down to the nanoscale. Due to its novelty as a polymeric material, no previous studies have approached a multiscale analysis of 3D-printed PEKK. The findings of this study contribute to a comprehensive understanding of 3D-printed PEKK along with criteria for process optimization in order to customize its properties to meet specific application requirements. This research not only advances the knowledge of PEKK as a 3D-printing material but also provides insights into the multifaceted nature of multiscale material characterization.

Keywords: anisotropy , digital image correlation , lattice structure , mechanical properties , micromechanical characterization , multiscale mechanics , nanoindentation , PEKK , viscous behavior

In the last 50 years, the number of companies producing automated devices for surgical operations has grown extensively. The population started to be more confident about the technology capabilities. The first patents related to surgical robotics are expiring and this knowledge is becoming a common base for the development of future surgical robotics. The review describes some of the most popular companies manufacturing surgical robots. The list of the company does not pretend to be exhaustive but wishes to give an overview of the sector. Due to space constraints, only a limited selction of companies is reported. Most of the companies described are born in America or Europe. Advantages and limitations of each product firm are described. A special focus is given to the end effectors; their shape and dexterity are crucial for the positive outcome of the surgical operations. New robots are developed every year, and existing robots are allowed to perform a wider range of procedures. Robotic technologies improve the abilities of surgeons in the domains of urology, gynecology, neurology, spine surgery, orthopedic reconstruction (knee, shoulder), hair restoration, oral surgery, thoracic surgery, laparoscopic surgery, and endoscopy.

Keywords: Commercial products , End effectors , Endoscopic , Robotic surgery , Robotically assisted , Surgical robotics

Segmentation of anatomical components is a major step in creating accurate and realistic 3D models of the human body, which are used in many clinical applications, including orthopedics. Recently, many deep learning approaches have been proposed to solve the problem of manual segmentation, which is time-consuming and operator-dependent. In the present study, SegResNet has been adapted from other domains, such as brain tumors, for knee joints, in particular, to segment the femoral bone from magnetic resonance images. This algorithm has been compared to the well-known U-Net in terms of evaluation metrics, such as the Dice similarity coefficient and Hausdorff distance. In the training phase, various combinations of hyperparameters, such as epochs and learning rates, have been tested to determine which combination produced the most accurate results. Based on their comparable results, both U-Net and SegResNet performed well in accurately segmenting the femur. Dice similarity coefficients of 0.94 and Hausdorff distances less than or equal to 1 mm indicate that both models are effective at capturing anatomical boundaries in the femur. According to the results of this study, SegResNet is a viable option for automating the creation of 3D femur models. In the future, the performance and applicability of SegResNet in real-world settings will be further validated and tested using a variety of datasets and clinical scenarios.

Keywords: 3D modeling knee , automated segmentation , CNN , computer-aided design , deep learning , machine learning for engineering applications , MONAI framework , SegResNet , U-Net

Introduction: Clinical gait analysis can be used to evaluate the recovery process of patients undergoing total hip arthroplasty (THA). The postoperative walking patterns of these patients can be significantly influenced by the choice of surgical approach, as each procedure alters distinct anatomical structures. The aim of this study is twofold. The first objective is to develop a gait model to describe the change in ambulation one week after THA. The secondary goal is to describe the differences associated with the surgical approach. Materials and methods: Thirty-six patients undergoing THA with lateral (n = 9), anterior (n = 15), and posterior (n = 12) approaches were included in the study. Walking before and 7 days after surgery was recorded using a markerless motion capture system. Exploratory Factor Analysis (EFA), a data reduction technique, condensed 21 spatiotemporal gait parameters to a smaller set of dominant variables. The EFA-derived gait domains were utilized to study post-surgical gait variations and to compare the post-surgical gait among the three groups. Results: Four distinct gait domains were identified. The most pronounced variation one week after surgery is in the Rhythm (gait cycle time: +32.9%), followed by Postural control (step width: +27.0%), Phases (stance time: +11.0%), and Pace (stride length: − 9.3%). In postsurgical walking, Phases is statistically significantly different in patients operated with the posterior approach compared to lateral (p-value = 0.017) and anterior (p-value = 0.002) approaches. Furthermore, stance time in the posterior approach group is significantly lower than in healthy individuals (p-value < 0.001). Conclusions: This study identified a four-component gait model specific to THA patients. The results showed that patients after THA have longer stride time but shorter stride length, wider base of support, and longer stance time, although the posterior group had a statistically significant shorter stance time than the others. The findings of this research have the potential to simplify the reporting of gait outcomes, reduce redundancy, and inform targeted interventions in regards to specific gait domains.

Keywords: Factor analysis , Gait analysis , Motion capture , Recovery of function , Surgical approach , Total hip replacement

Total hip arthroplasty (THA) is a surgical procedure advised to treat end-stage osteoarthritis. There are several surgical approaches involving different biomechanical effects, potentially affecting the outcome. A possible consequence of THA is the Trendelenburg gait, which consists of a pelvis drop and trunk lean during walking due to a unilateral weakness of the hip abductors. Gait analysis can be useful in assessing the disorder. The purpose of the present research is twofold: i) to assess the Trendelenburg disease in patients undergoing THA through gait analysis; ii) to investigate the relationship between the disorder and surgical approaches. Patients' gaits were recorded 7 days after THA surgery, using two Microsoft Kinect V2 sensors and virtual skeletons were reconstructed by iPi Soft software. A customized tool was developed to automatically identify walking phases and recognize characteristics compatible with the Trendelenburg gait. In addition to pelvic drop and trunk lean in the frontal plane, kinematic measurements are proposed for a more complete assessment of the Trendelenburg gait. These variables are found to be effective in highlighting the differences between surgical approaches.

Keywords: Gait Analysis , Motion Capture , Recovery of Function , Total Hip Arthroplasty , Trendelenburg Gait

The correct execution of scanning protocols is crucial to ensure the quality of radiographic examinations. Recent advances in machine learning methods have opened up new possibilities for medical imaging. However, the potential of pose estimation models in this field is still largely unexplored. This study aims to address this gap by investigating the performance and an application of pose estimation in the context of X-ray image acquisition. To this goal, a pose estimation model was selected from a pool of state-of-the-art models. It was then trained on a dataset of 213 images of humans undergoing X-ray imaging. Despite the limited size of the dataset, the model achieved an AP of 0.902 and a near real-time inference speed of 7 FPS on CPU. The detection of landmarks through pose estimation enables the automatic assessment of pose adherence to prescribed imaging protocols. This automation can reduce human errors and alleviate the mental workload on radiologists. The results of this study highlight the potential of convolutional neural network-based pose estimation models to assist radiologists in performing X-ray imaging tasks effectively.

Keywords: Convolutional Neural Networks , Deep Learning , Optical Imaging , Pose Estimation , Radiography

Autologous ear reconstruction is a surgical procedure performed in the case of defects of the outer ear in which the malformed anatomy is reconstructed with autologous cartilage tissue and often involves the use of surgical guides modelled from a digital reconstruction of the ear anatomy. To obtain such three-dimensional anatomy, traditional imaging methods, which are expensive and invasive, can be replaced by professional 3D scanners or low-cost commercial devices. In this context, this paper focuses on the evaluation of two devices for the acquisition of the outer ear, the Intel® RealSense D405™ (stereo camera) and the TrueDepth camera of the iPhone® 13 (structured light camera), proposing a comparison based on four parameters: accuracy, precision, deviation range and point-to-point distance, in order to assess their usability in the medical field, and in particular in the context of autologous ear reconstruction. The results show that, despite significantly different handling of the raw data, the performance of the two devices is comparable: average accuracy is 0.76 mm for the D405 and 0.95 mm for the iPhone 13, average precision is 0.071 mm for the D405 and 0.065 mm for the iPhone 13, average range of deviation is 3.12 mm for the D405 and 3.64 mm for the iPhone 13.

Keywords: 3D scanning , Accuracy assessment , Ear reconstruction , RealSense D405 , TrueDepth camera

Nowadays the interest for improving methodologies to design customized external devices for the neck has considerably grown, considered that neck pathologies are widespread among the population. Their design for additive manufacturing starts by acquiring the body's part and, in order to achieve a satisfactory end result, the support of accurate reconstructed models from fast scans is relevant. At this aim, the availability of an average or statistical model could be potentially useful for reducing acquisition time and for upgrading low-resolution scans. This paper focuses on the application of a methodology for the creation of an average model of human neck. The method required the use of a set of scans, acquired by means of a structured light scanner, from which an accurate reconstruction of the neck surface was obtained. A number of healthy subjects of both genders was considered and the digital neck surfaces were used for creating an average digital model for males and for females. The methodology developed was based on mesh morphing and was applied to the sample considered with satisfactory results. The procedure is also suitable for the development of statistical models of the neck, that will cover future research

Keywords: Acquisition , Mesh morphing , Neck , Reverse Engineering

Aim: The objective of this research has been to apply a specific simulation to a patient to assess the biomechanical consequences of rotating an upper canine tooth through different attachment–aligner configurations and to predict the most efficient design using a three-dimensional finite element model of a full maxillary arch of a specific patient. Materials and methods: This was obtained by combining Cone-Beam Computed Tomography (CBCT) with the aim of reconstructing tooth roots and bone tissues, and Surface Structured-Light Scanning for creating digital tooth crown models from the patient's impressions. This model was imported into the finite element solver (Ansys® 17). Three different attachment–aligner combinations were created through the exploitation of computer-aided design (CAD) procedures, i.e., without attachments, with a couple of attachments and with an attachment and a pressure point. For each simulation, the resulting force–moment (MF) system applied by the aligner to the target tooth, as well as the tooth displacement and rotation, was computed using a workstation based on Intel Xeon CPU E3-1245 v3@3.40 GHz and 16 GB RAM. Simulations reported that by adding the pressure point and the attachment to the standard aligner the amount of Moment z (Mz) delivered to the tooth increased almost two times. Results and conclusions: The maximum tooth displacement (0.85 mm) was obtained with the attachment and pressure point aligner, while the lowest (0.058 mm) was obtained with use of a couple of attachments. Both the attachment and the pressure point have the potential to enhance the appliance's effectiveness. Particularly, the pressure point showed a higher influence on the load absolute value. The method applied in the present study should be used to retrieve the best design configuration for each patient and specific tooth movement

Keywords: aligners , digital workflow , finite element analysis , malocclusion , orthodontic movement , three-dimensional diagnosis and analysis , three-dimensional tooth movement

3D printed patient-specific hand orthoses can improve the efficiency of the treatment and the comfort of the patient, but since each customized orthosis is a virtually unique device, it is difficult to assess their mechanical response in the design phase, both experimentally and numerically. The Finite Element Method (FEM) could be used to predict the deformation of the orthosis under predetermined loads, but patient-specific models including interaction with the hand are still lacking. In the present work we present a computational model in which, starting from the scan data of the hand used to manufacture the orthosis, a FEM model of the hand is generated, including a skeletal structure. Hand bones positions and dimensions can be defined basing on simple anatomical measurements or literature data and the stiffness of the joints can be tuned in relation to patient pathology. The remaining hand volume consists of a soft tissue region, mimicking the non-linear mechanical behaviour of skin and muscles. Results show that both functional and structural indexes can be analyzed, such as contact pressures, stress state or the compliance of the orthosis, providing useful information for the design of custom devices. By using mesh deformation algorithms, the scan data could be used to generate different orthosis designs in target positions defined by the therapist and, taking advantage of a parametric model under development, the skeletal structure could be adapted correspondingly, providing an innovative pathway to investigate the response of the orthosis during the whole rehabilitation.

Keywords: 3D Printing , FEM , Hand Orthosys

The paper presents a hybrid user-centred/simulation approach to populate the design specification. It presents an application in the field of exoskeleton design, with the final goal to support workers to carry out their professional tasks. More than 100 professionals (mostly health workers) participated in the survey. The qualitative requirements were extracted are then tested in simulation environments. The approach proved to generate meaningful results for product concept generation. Beyond the expectations, the simulation also showed more adequate product architectures.

Keywords: exoskeletons , product design , product planning , requirements management , user-centred design