Diana Popescu

Rapid prototyping for patient-specific surgical orthopaedics guides: A systematic literature review

There has been a lot of hype surrounding the advantages to be gained from rapid prototyping processes in a number of fields, including medicine. Our literature review aims objectively to assess how effective patient-specific surgical guides manufactured using rapid prototyping are in a number of orthopaedic surgical applications. To this end, we carried out a systematic review to identify and analyse clinical and experimental literature studies in which rapid prototyping patient-specific surgical guides are used, focusing especially on those that entail quantifiable outcomes and, at the same time, providing details on the guides’ design and type of manufacturing process. Here, it should be mentioned that in this field there are not yet medium- or long-term data, and no information on revisions. In the reviewed studies, the reported positive opinions on the use of rapid prototyping patient-specific surgical guides relate to the following main advantages: reduction in operating times, low costs and improvements in the accuracy of surgical interventions thanks to guides’ personalisation. However, disadvantages and sources of errors which can cause patient-specific surgical guide failures are as well discussed by authors. Stereolithography is the main rapid prototyping process employed in these applications although fused deposition modelling or selective laser sintering processes can also satisfy the requirements of these applications in terms of material properties, manufacturing accuracy and construction time. Another of our findings was that individualised drill guides for spinal surgery are currently the favourite candidates for manufacture using rapid prototyping. Other emerging applications relate to complex orthopaedic surgery of the extremities: the forearm and foot. Several procedures such as osteotomies for radius malunions or tarsal coalition could become standard, thanks to the significant assistance provided by rapid prototyping patient-specific surgical guides in planning and performing such operations.

Development of Bioabsorbable Interference Screws: How Biomaterials Composition and Clinical and Retrieval Studies Influence the Innovative Screw Design and Manufacturing Processes

The current development of bioresorbable materials provided the support for improvement of the clinical performance of the interference screws used during knee-ligament reconstruction. In general, commercially available biodegradable interference screws used in clinical practice are chemically based on degradable, but now a trend to use biodegradable composite materials using the same synthetic biodegradable polymers as matrix reinforced with biodegradable ceramics could be observed. Hydroxyapatite or tricalcium phosphate are used as ceramics in order to reduce the foreign body reaction and increase osteoconduction and mechanical properties of the biodegradable composite materials. In our study several new design features of an innovative interference screw were proposed in order to ameliorate press-fit fixation without damaging the graft based on clinical experience, retrieval analysis of some failed screw, and finite element simulation. We proposed a self-tapping screw with conical shape and three cutting flutes at the distal end and cylindrical shape at the proximal end. The clinical performance of an interference screw is assured by the combination between the clinical technique, screw design, and biodegradable composite material properties, which guarantees the integrity of the screw during insertion, the tissue regrowth, and the stability of fixation.

Implementation and evaluation of a model processing pipeline for assembly simulation

Purpose The paper aims to present the processing pipeline of an assembly immersive simulation application which can manage the interaction between the virtual scene and user using stereoscopic display and haptic devices. A new set of elements are integrated in a Collaborative Virtual Environment (CVE) and validated using an approach based on subjective and objective users’ performance criteria. The developed application is intended for Assembly/Disassembly (A/D) analysis, planning and training. Design/methodology/approach A mobility module based on contact information is used to handle the assembly components’ movements through real-time management of collision detection and kinematically constraint guidance. Information on CVE architecture, modules and application configuration process are presented. Impact of device type (3 degrees of freedom (DoFs) vs 6 DoFs) over user’s experience is evaluated. Parameters (number of assembled components and components assembly time) are measured for each user and each haptic device, and results are compared and discussed. Findings Test results proved the efficiency of using a mobility module based on predefined kinematic constraints for reducing the complexity of collision detection algorithms in real-time assembly haptic simulations. Also, experiments showed that, generally, users performed better with 3 DoFs haptic device compared to 6 DoFs haptic equipment. Originality/value The proposed immersive application automates the kinematical joints inference from 3D computer-aided design (CAD) assembly models and integrates it within a haptic-based virtual environment, for increasing the efficiency of A/D process simulations.

Intelligent Collaborative Platform for Development of Personalized Surgical Orthopedic Guides

Currently, the processes of developing new medical devices (in particular, patient specific guides for orthopedic surgery being of interest in our research), is hampered by the difficulty of correctly and efficiently quantifying and translating the specific medical requirements in terms of technical specifications. This is caused by the intrinsic difficulty of the demarche, but also by a complicated communication between surgeon and engineer given the different practical and research perspectives, specific constraints, motivation, evaluation criteria and professional language barrier. The advent and development of new technologies with applications in the medical field, such as robotics, haptic-based virtual and augmented reality, additive manufacturing, collaborative modeling, knowledge-based support decision systems, etc., make now possible to bridge the gap between surgeons’ ideas and needs and their practical materialization into new customized medical devices. The paper enrolls in this research trend, presenting a general framework for the development of an intelligent e-health platform, which provides in a collaborative environment the necessary knowledge and computer-aided tools for translating surgeons’ needs into technical specifications for the design and manufacturing of patient-specific guides for orthopedic surgery. These guides can be used in the minimally invasive surgical procedures and for reducing the x-ray radiation exposure during surgery, and for increasing accuracy in performing different types of specific orthopedic surgical procedures such as cutting, drilling, tapping and aligning, by transferring the tools trajectories from computer-aided planning to surgery.

Automated Stand for Non-Destructive Testing Evaluation of Metal Products

Problem be used for evaluating products quality: - Destructive evaluation, in which the product is destroyed in order to analyse its properties and internal structure; - Non destructive evaluation (NDE), used for identifying defect and irregularities, without damaging the product. These non destructive evaluation methods include [1-4]: ‐ Visual and optical testing – VT; ‐ Magnetic particle testing – MT; ‐ Liquid penetrant testing –PT; ‐ Radiographic testing – RT ; ‐ Ultrasounds testing – UT; ‐ Eddy current testing – ET; One of the most frequently used method of non destructive examination is PT or dye penetrant testing (DPT), due to the low costs involved, ease of use and flexibility, suitability to a large number of applications. This method evaluates the presence of open discontinuities (or cracks) on the surface part, based on reverse capillary action and on the developer absorption effect which draw out penetrant and produces indications visible for the inspector (see fig.1 for a principle scheme of LP examination [5]). Although widely used, PT has several disadvantages: - Limitation to surface defects or to the defects which communicates with the surface; - Only products with non porous surfaces (or with low porosity) can be inspected; - Important amount of time used for manipulating the parts during inspection; - Results interpretation heavily depends on subjective aspects such as operator experience, knowledge and motivation. In order to eliminate or reduce the operator involvement in the process steps, research has being made for automating the process, such examples of liquid penetrant inspection lines can be found in [10-15]. However, in all analysed automated PT systems, the inspection is still made visually by an inspector, who gives a pass/fail grade for the inspected parts. The difficulty of fully automating the liquid penetrant inspection process is due not only to the necessity to precisely determine and control process parameters (dwell time, developer time, drying time, quantity of penetrant, developer and cleaning water, pressure for spraying solutions with penetrant, developer and cleaning water, transport speed, etc.) but also to the evaluation and results interpretation process. Thus, even if there are patents [16-17] which present approaches and general frameworks for fully-automated LPT systems, including also automatic image processing of the flaws, to the best of the authors’ knowledge, these equipment are not yet implemented. In this context, this paper presents an experimental stand for a fully automated liquid penetrant inspection line, which includes the development and use of dedicated imaging software used for real time interpretation of the images acquired using a digital camera. The novelty of the research consist in designing and building a fully-automated LPT stand, controlled by a soft which contains also a module for acquisition and image processing in real time without no human implication.

Advanced Engineering in Orthopedic Surgery Applications

The paper reports the use of advanced engineering tools, techniques and manufacturing process for the preoperative planning, visualization and simulation of complex osteotomy of a diabetic foot (Charcot osteoarthropathy). Two case studies focused on the same clinical data are illustrating the use of medical modeling techniques, reverse engineering and Additive Manufacturing technology in the development of 3D printed anatomical model and customized surgical cutting guides, as well as the use of Augmented Reality (AR) tools for enhancing the communication and information exchange between surgeons, and between surgeons and engineers. A good and accurate communication surgeon-engineer in identifying and selecting anatomical landmarks and supporting surfaces, in establishing the resections trajectories and K-wires positions proved mandatory for the guides’ design process. The importance of using both 3D virtual models, AR models and physical models as collaboration tools is also discussed.

How to design and additive manufacture individualized surgical guides for hand osteotomy

The paper focuses on the design and additive manufacturing of patient-specific surgical guides, in particular for hand osteotomy. The use of these guides allows the surgeon to better orient during surgery, improves intervention accuracy, reduces surgery time and cost and decreases X-ray exposure. They can be used for routine activities or for new and complicated surgical procedures. The processes of design and manufacturing these guides involve tight collaboration between surgeon and engineer for correctly transferring medical requirements into technical specification, which can be a difficult task due to professional language barrier, specific constraints, etc. Therefore, starting from the approach used so far in practice, the paper fundaments the need and presents the current status of implementation of an intelligent online platform, as a modern solution to overcome miscommunication problems and to ensure a degree of automation to a workflow which otherwise has to be resumed for each patient/clinical case.

Virtual Reality in Orthopedic Surgeons Training

Nowadays the use of Virtual Reality (VR) based surgical simulators or training environments is becoming more and more spread in the medical world. These are usually dedicated to the development and improvement of novice trainees’ skills by helping them to learn different surgical techniques, to use proper instrumentation or to practice surgical protocols, but also in the training of expert surgeons for conserving their skills, for planning or rehearsing new, complicated or rare procedures. In this general context of interest, our paper aims at answering the following questions: What are the main requirements for a haptic device in order to be successfully used in the virtual training of orthopedic surgeons What requirements are mandatory to be included in an orthopedic surgery haptic-based training application for providing a realistic user’s experience These are legitimate questions considering that surgical education can really benefit the advantages offered by such virtual simulators only if they can satisfy a list of requirements among which high level of immersion and interactivity, realistic 3D virtual models and constraints of anatomical structures, good correspondence between real and simulated cases (i.e. a natural ‘behavior’ and ‘feeling’ of simulated anatomy). The focus of the literature review presented in this paper will be on orthopedic VR simulators for drilling, sawing and fixing implants screws, pins and plates, with an emphasize on devices’ characteristics and applications features. This study enrolls in the trend of improving user’s immersion experience at a cost as low as possible, representing the basis on which an innovative and affordable haptic device and an application for training basic orthopedic surgical skills are proposed for development in further research.

Method and Software for Analyzing the Assembly/Disassembly Operations of Mechanical Products

Enrolling in the current trends of using collaborative virtual environments and virtual reality techniques for engineering applications, the current paper presents the synthetic results of a research in which an innovative method and software application were developed for analyzing and simulating the Assembly/Disassembly (A/D) operations of mechanical products. Starting from the 3D CAD model of an assembly and using connection interface and mobility operator concepts, the application supports the designers in generating valid A/D plans by determining the interfaces between components, calculating the components mobility and identifying the functional role of components in an assembly. Thus, the developed software provides designers an automated tool for analyzing A/D operations, obtaining and simulating A/D sequences, useful in the design phase of a mechanical product, for training the operators, as well as for improving the productivity of activities such as recycling, maintenance and reusing. Moreover, the application was conceived so that, in a further step, to be integrated in an immersive environment, offering a realistic simulation in two modes of interaction: free mode and kinematically guided. Finally, in order to validate the proposed methods and concepts, the application was tested for evaluating users’ satisfaction degree.

Innovative Therapeutic Kit for Magnetically Controlled Viscosupplementation Treatment of Knee Osteoarthritis

The therapeutic attitude for degenerative knee joint damage (such as osteoarthritis) consists in a complex protocol which starts with physiotherapy sessions, involves the use of specific devices — orthosis for sustaining the affected joint, and includes intra-articular infiltrations for reducing the pain, improving joint mobility and minimizing functional deterioration [1, 2].Copyright