Affordable passive 3D-printed prosthesis for persons with partial hand amputation

Background and Aim: Partial hand amputations are common in developing countries and have a negative impact on patients and their families’ quality of life. The uniqueness of each partial hand amputation, coupled with the relatively high costs of prostheses, makes it challenging to provide suitable prosthetic solutions in developing countries. Current solutions often have long lead times and require a high level of expertise to produce. The aim of this study was to design and develop an affordable patient-specific partial hand prosthesis for developing countries. Technique: The prosthesis was designed for a patient with transmetacarpal amputation (i.e. three amputated fingers and partial palm). The final design was passive, controlled by the contralateral hand, and utilized the advanced flexibility properties of thermoplastic polyurethane in a glove-like design that costs approximately 20 USD to fabricate. Quantitative and qualitative tests were conducted to assess performance of the device after the patient used the final design. A qualitative assessment was performed to gather the patient’s feedback following a series of tests of grasp taxonomy. A quantitative assessment was performed through a grasp and lift test to measure the prosthesis’ maximum load capacity. Discussion: This study showed that the prosthesis enhanced the patient’s manual handling capabilities, mainly in the form of grasp stability. The prosthesis was light weight and could be donned and doffed by the patient independently. Limitations include the need to use the contralateral hand to achieve grasping and low grasp strength. Clinical relevance: Persons with partial hand amputation in developing countries lack access to affordable functional prostheses, hindering their ability to participate in the community. 3D-printed prostheses can provide a low-cost solution that is adaptable to different amputation configurations

Reservoir Cannulas for Pediatric Oxygen Therapy: A Proof-of-Concept Study

Hypoxemia is a complication of pneumonia—the leading infectious cause of death in children worldwide. Treatment generally requires oxygen-enriched air, but access in low-resource settings is expensive and unreliable. We explored use of reservoir cannulas (RCs), which yield oxygen savings in adults but have not been examined in children. Toddler, small child, and adolescent breathing profiles were simulated with artificial lung and airway models. An oxygen concentrator provided flow rates of 0 to 5 L/min via a standard nasal cannula (NC) or RC, and delivered oxygen fraction (FdO2) was measured. The oxygen savings ratio (SR) and absolute flow savings (AFS) were calculated, comparing NC and RC. We demonstrated proof-of-concept that pendant RCs could conserve oxygen during pediatric therapy. SR mean and standard deviation were 1.1±0.2 to 1.4±0.4, 1.1±0.1 to 1.7±0.3, and 1.3±0.1 to 2.4±0.3 for toddler, small child, and adolescent models, respectively. Maximum AFS observed were 0.3±0.3, 0.2±0.1, and 1.4±0.3 L/min for the same models. RCs have the potential to reduce oxygen consumption during treatment of hypoxemia in children; however, further evaluation of products is needed, followed by clinical analysis in patients

Distributed manufacturing of open source medical hardware for pandemics

Distributed digital manufacturing offers a solution to medical supply and technology shortages during pandemics. To prepare for the next pandemic, this study reviews the state-of-the-art of open hardware designs needed in a COVID-19-like pandemic. It evaluates the readiness of the top twenty technologies requested by the Government of India. The results show that the majority of the actual medical products have some open source development, however, only 15% of the supporting technologies required to produce them are freely available. The results show there is still considerable research needed to provide open source paths for the development of all the medical hardware needed during pandemics. Five core areas of future research are discussed, which include (i) technical development of a wide-range of open source solutions for all medical supplies and devices, (ii) policies that protect the productivity of laboratories, makerspaces, and fabrication facilities during a pandemic, as well as (iii) streamlining the regulatory process, (iv) developing Good-Samaritan laws to protect makers and designers of open medical hardware, as well as to compel those with knowledge that will save lives to share it, and (v) requiring all citizen-funded research to be released with free and open source licenses

Data augmentation using background replacement for automated sorting of littered waste

The introduction of sophisticated waste treatment plants is making the process of trash sorting and recycling more and more effective and eco-friendly. Studies on Automated Waste Sorting (AWS) are greatly contributing to making the whole recycling process more efficient. However, a relevant issue, which remains unsolved, is how to deal with the large amount of waste that is littered in the environment instead of being collected properly. In this paper, we introduce BackRep: a method for building waste recognizers that can be used for identifying and sorting littered waste directly where it is found. BackRep consists of a data-augmentation procedure, which expands existing datasets by cropping solid waste in images taken on a uniform (white) background and superimposing it on more realistic backgrounds. For our purpose, realistic backgrounds are those representing places where solid waste is usually littered. To experiment with our data-augmentation procedure, we produced a new dataset in realistic settings. We observed that waste recognizers trained on augmented data actually outperform those trained on existing datasets. Hence, our data-augmentation procedure seems a viable approach to support the development of waste recognizers for urban and wild environments

Effect of the Thumb Orientation and Actuation on the Functionality and Performance of Affordable Prosthetic Hands: Obtaining Design Criteria

The advent of 3D printing technologies has enabled the development of low-cost prosthetic underactuated hands, with cables working as tendons for flexion. Despite the particular relevance to human grasp, its conception in prosthetics is based on vague intuitions of the designers due to the lack of studies on its relevance to the functionality and performance of the device. In this work, some criteria for designers are provided regarding the carpometacarpal joint of the thumb in these devices. To this end, we studied four prosthetic hands of similar characteristics with the motion of abduction/adduction of the thumb resolved in three different ways: fixed at a certain abduction, coupled with the motion of flexion/extension, and actuated independently of the flexion/extension. The functionality and performance of the hands were assessed for the basic grasps using the Anthropomorphic Hand Assessment Protocol (AHAP) and a reduced version of the Southampton Hand Assessment Procedure (SHAP). As a general rule, it seems desirable that thumb adduction/abduction is performed independently of flexion/extension, although this adds one degree of control. If having this additional degree of control is beyond debate, coupled flexion/extension and adduction/abduction should be avoided in favour of the thumb having a fixed slight palmar abduction.This research was supported by the Spanish MINECO, AEI, and ERDF under Grant DPI2017-89910-R; the MICIN/AEI/10.13039/501100011033 for the project PID2020-118021RB-I00; the Generalitat Valenciana under Grant GV/2018/125; and the Universitat Jaume I under Grant UJI-B2017-70

Mathematics teachers' pedagogy through technology: A systematic literature review

Mathematics teachers' pedagogy (MTP) is an integral part of classroom instructional mediation through technology or manipulatives. This article describes a logical literature analysis for the MTP and technology with GeoGebra (GG). The findings reveal the intervention impact of MTP with GG and other technologies such as matrix laboratory (MATLAB); an interactive whiteboard (IWB) and computer algebra system (CAS); wxMaxima, which is a CAS; information and communication technologies (ICT); concrete materials as well as other resources in developing students' performances in mathematics which were generally effective too. The systematic literature review (SLR) explored findings from current research between January 2011 and October 2020. Quality assessment screening of the papers was done and alongside further elimination of repeated documents from the analysis, twenty-eight publications met the refinement and inclusion/exclusion criteria out of 110 papers. The modified preferred reporting items for systematic reviews and meta-analyses (PRISMA) outline exemplifies the literature review accordingly. The authors observed, accomplished, and discussed the significance of the SLR. This was followed by the constraints, upcoming directions for MTP with technology and GG, and the MTP consequences for education and research

Free and Open Source 3-D Model Customizer for Websites to Democratize Design with OpenSCAD

International audience3-D printing has entered the consumer market because of recent radical price declines. Consumers can save substantial money by offsetting purchases with DIY pre-designed 3-D printed products. However, even more value can be obtained with distributed manufacturing using mass customization. Unfortunately, the average consumer is not technically sophisticated enough to easily design their own products. One solution to this is the use of an overlay on OpenSCAD parametric code, although current solutions force users to relinquish all rights to their own designs. There is thus a substantial need in the open source design community for a libre 3-D model customizer, which can be used in any design repository to democratize design. This study reports on the design, function, and validation of such software: the Free Open Source 3-D Customizer. It is demonstrated with a case study of the customization of 3-D printable external breast prosthetics. The results showed that novice users can adjust the available parameters according to their needs and save these to a new file on a website. This PHP (recursive acronym for PHP: Hypertext Preprocessor) library is free and open source and has potential for increasing the usefulness of online repositories to enable distributed manufacturing using consumer customized 3-D printable products

Simplified Negative Pressure Wound Therapy Device for Application in Low-Resource Settings

Negative pressure wound therapy (NPWT) provides proven wound healing benefits and is often a desirable wound treatment. Unfortunately, NPWT devices are not widely available in low-resource settings (LRSs). In order to overcome identified NPWT barriers, a simplified NPWT (sNPWT) system was designed and iteratively improved during field-based testing. The sNPWT technology, our device design iterations, and the design-based results of our field tests are described. The sNPWT system includes a bellows hand pump, an occlusive drape, and a tube with tube connectors, connecting the drape to the pump. The most critical property of a sNPWT system is that it must be airtight. The details of the design iterations needed to achieve an occlusive system are explained. During the design process, the sNPWT system was tested during the earthquake relief in Haiti. This testing found that a liquid sealant was necessary to seal the drape to the peri-wound skin. A study conducted in Rwanda verified that a liquid latex sealant was safe to use and that the tube connector must be connected to the drape with an airtight method during the manufacturing process. This work has shown that sNPWT is feasible in LRSs. Since the completion of the clinical testing, the design has been further evolved and the developers are working with contract manufactures to produce the final design and preparing for regulatory approval applications

3D PRINTING IN LOW RESOURCE HEALTHCARE SETTINGS: ANALYSIS OF POTENTIAL IMPLEMENTATIONS

3D printing has gained significant momentum in the past ten years, and its unique advantages make it especially ideal for use in low resource healthcare settings, where many designs have already been successfully implemented. Yet, little has been studied on how 3D printing can be sustainably and functionally implemented in low resource healthcare systems as a manufacturing practice. In this report, three business models are proposed for this implementation: In-House Operator, Independent Operator, and Print Farm. These models were then tested over four months in Kisumu county, Kenya, at two workshops and seven public hospitals. I worked with local medical professionals, engineers, and government officials to create and test 3D printed medical products. Human centered design criteria were used to assess the models. All three business models proved to have individual distinct benefits and challenges for application. However, specific contextual considerations are necessary to decide which implementation is the most sustainable. Through these findings, others may begin implementing more robust 3D printing systems in low resource healthcare contexts throughout the globe