Um novo modelo de conceito para implantes ortopédicos instrumentados ativos

Doutoramento em Engenharia MecânicaTotal hip replacement (THR) is one of the most performed surgical procedures around the world. Millions of THR are carried out worldwide each year. Currently, THR revision rates can be higher than 10%. A significant increase of the number of primary and revision THRs, mainly among patients less than 65 years old (including those under 45 years old) has been predicted for the forthcoming years. A worldwide increase in the use of uncemented fixation has also been reported, incidence caused mainly by the significant increase of more active and/or younger patients. Besides the significant breakthroughs for uncemented fixations, they have not been able to ensure long-term implant survival. Up to date, current implant models have shown evidences of their inability to avoid revision procedures. The performance of implants will be optimized if they are designed to perform an effective control over the osseointegration process. To pursue this goal, improved surgical techniques and rehabilitation protocols, innovative bioactive coatings (including those for controlled delivery of drugs and/or other bio-agents in the bone-implant interface), the concepts of Passive Instrumented Implant and Active Instrumented Implant have been proposed. However, there are no conclusive demonstrations of the effectiveness of such methodologies. The main goal of this thesis is to propose a new concept model for instrumented implants to optimize the bone-implant integration: the self-powered instrumented active implant with ability to deliver controlled and personalized biophysical stimuli to target tissue areas. The need of such a new model is demonstrated by optimality analyses conducted to study the performance of instrumented and non-instrumented orthopaedic implants. Promising results on the potential of a therapeutic actuation driven by cosurface-based capacitive stimulation were achieved, as well as for self-powering instrumented active implants by magnetic levitation-based electromagnetic energy harvesting.A artroplastia total da anca (THR) é um dos procedimentos cirúrgicos mais realizados à escala global. Milhões de THRs são realizadas todos os anos em todo o mundo. Atualmente, as taxas de revisão destas artroplastias podem ser superiores a 10%. O número de THRs primárias e de revisão têm aumentado e estima-se que cresçam acentuadamente nos próximos anos, principalmente em pacientes com idades inferiores a 65 anos (incluindo aqueles com menos de 45 anos). Também se tem verificado uma tendência generalizada para o uso de fixações não cimentadas, incidência principalmente causada pelo aumento significativo de pacientes mais jovens e/ou activos. Embora se tenham realizado avanços científicos no projeto de implantes não cimentados, têm-se verificado o seu insucesso a longo-prazo. Encontram-se evidências da ineficácia dos modelos de implantes que têm sido desenvolvidos para evitar procedimentos de revisão. O desempenho dos implantes será otimizado se estes foram projetados para controlarem eficazmente o processo de osseointegração. Para se alcançar este objetivo, têm sido propostas a melhoria das técnicas cirúrgicas e dos protocolos de reabilitação, a inovação dos revestimentos (onde se incluem os revestimentos ativos projetados para a libertação controlada de fármacos e/ou outros bio-agentes) e os conceitos de Implante Instrumentado Passivo e Implante Instrumentado Ativo. Contudo, não existem demonstrações conclusivas da eficácia de tais metodologias. O principal objetivo desta tese é propor um novo modelo de conceito para implantes instrumentados para se otimizar a integração osso-implante: o implante instrumentado ativo, energeticamente auto-suficiente, com capacidade de aplicar estímulos biofísicos em tecidos-alvo de forma controlada e personalizada. A necessidade de um novo modelo é demonstrada através da realização de análises de otimalidade ao desempenho dos implantes instrumentados e não-instrumentados. Foram encontrados resultados promissores para o controlo otimizado da osseointegração usando este novo modelo, através da atuação terapêutica baseada na estimulação capacitiva com arquitetura em co-superfície, assim como para fornecer energia elétrica de forma autónoma por mecanismos de transdução baseados em indução eletromagnética usando configurações baseadas na levitação magnética

Southwest Research Institute assistance to NASA in biomedical areas of the technology utilization program Final report, 1 Feb. 1969 - 24 Aug. 1970

Research progress in technology transfer by NASA Biomedical Application Tea

An investigation of the forces within the tibiae at typical blast loading rates : with different boots

Includes bibliographical references.Anti-Vehicular Landmines (AVLs), underbelly Improvised Explosive Devices (IEDs) or side-attack IEDs are some of the major threats to military vehicles and their occupants (Ramasamy et al., 2011). The lower extremities of the occupants are very prone to injury, mostly caused by underbelly detonation of AVLs or IEDs due to their spatial proximity to the rapidly deforming floor of a vehicle in response to the threat mechanism. Lower limb surrogate legs, such as a Hybrid III or Military Lower Extremity (MiL-Lx) legs, are used to quantify the impulse loading on the lower extremities when subjected to the forces of the rapidly deforming floor. These surrogate legs are also used in laboratories for simulated blast loading tests and scaled field tests to evaluate protection measures for the lower extremities. In this study, the responses of the HIII and MiL-Lx surrogate legs were evaluated at several blast loading conditions using the Modified Lower Limb Impactor. The impact tests were conducted using a lower limb impactor with the leg mounted vertically and attached to the knee of the Anthropomorphic Test Device (ATD). The MiL-Lx leg is a recently developed surrogate which has limited evaluation across the loading conditions. This work evaluated the MiL-Lx leg across a range of velocities from 2.7 – 10.2 m/s. The study also included the evaluation of the response of the surrogate legs when fitted with two different types of combat boot. The current study shows that the response of the MiL-Lx leg compares satisfactorily with a previous study of a simulated blast at 7.2 m/s and the Post Mortem Human Subject (PMHS) corridors conducted at Wayne State University (WSU), Michigan, U.S.A. The MiL-Lx leg force-time trajectories from both the lower and upper tibia load cell were found to have distinct features that can be related to the impactor dynamics. This observation implies that the response of the legs can be used to deduce the dynamics of the impactor or deforming floor. The MiL-Lx leg results measured by the lower tibia load cell shows that the combat boots mitigate the peak tibia force and delay the time to peak force. However, the results from the upper tibia load cell show that the boots did not reduce high-severity force, but only the delays the time-to-peak force. The upper tibia load cell did not show any potential mitigation capability of the combat boots. The HIII leg force-time trajectories from both the lower and upper load cells showed a similar bell shape and duration but different magnitudes. Both the lower and upper tibia load cells of the HIII leg showed that the combat boots had mitigation capabilities. This is the first time that the lower tibia response of the MiL-Lx leg has been tested and analysed at a range of loading conditions. This has resulted in better understanding of the response of the MiL-Lx leg and will ultimately lead to better protection measures of the lower extremities

Vibration

Studies on hand-transmitted vibration exposure, biodynamic responses, and biological effects were conducted by researchers at the Health Effects Laboratory Division (HELD) of the National Institute for Occupational Safety and Health (NIOSH) during the last 20 years. These studies are systematically reviewed in this report, along with the identification of areas where additional research is needed. The majority of the studies cover the following aspects: (i) the methods and techniques for measuring hand-transmitted vibration exposure; (ii) vibration biodynamics of the hand-arm system and the quantification of vibration exposure; (iii) biological effects of hand-transmitted vibration exposure; (iv) measurements of vibration-induced health effects; (iv) quantification of influencing biomechanical effects; and (v) intervention methods and technologies for controlling hand-transmitted vibration exposure. The major findings of the studies are summarized and discussed.CC999999/ImCDC/Intramural CDC HHSUnited States/2021-01-18T00:00:00Z34414357PMC83715621023

Excellentia Eminentia Effectio

"In these pages you will learn about the fascinating research endeavors that each of our faculty members is undertaking. We have divided their research into the broad categories of health, sustainability, information, and systems. While we recognize the imperfect nature of categorizing research that, by its very nature may be interdisciplinary or transdisciplinary, we nonetheless believe it will be helpful as a way to see the depth and breadth of our research endeavors within each grouping. As you read the profiles on these pages, I know you will begin to appreciate that, taken as a whole, the research spectrum at Columbia Engineering is exceptional and that, as our professors go about their work, they are at the cusp of making breakthroughs that will have a major impact on the way we live our lives today and tomorrow.

Cells in Space

Discussions and presentations addressed three aspects of cell research in space: the suitability of the cell as a subject in microgravity experiments, the requirements for generic flight hardware to support cell research, and the potential for collaboration between academia, industry, and government to develop these studies in space. Synopses are given for the presentations and follow-on discussions at the conference and papers are presented from which the presentations were based. An Executive Summary outlines the recommendations and conclusions generated at the conference

Southwest Research Institute assistance to NASA in biomedical areas of the technology

Significant applications of aerospace technology were achieved. These applications include: a miniaturized, noninvasive system to telemeter electrocardiographic signals of heart transplant patients during their recuperative period as graded situations are introduced; and economical vital signs monitor for use in nursing homes and rehabilitation hospitals to indicate the onset of respiratory arrest; an implantable telemetry system to indicate the onset of the rejection phenomenon in animals undergoing cardiac transplants; an exceptionally accurate current proportional temperature controller for pollution studies; an automatic, atraumatic blood pressure measurement device; materials for protecting burned areas in contact with joint bender splints; a detector to signal the passage of animals by a given point during ecology studies; and special cushioning for use with below-knee amputees to protect the integrity of the skin at the stump/prosthesis interface

Delivery Optimization and Evaluation of Biomechanics of an Injectable Nucleus Pulposus Replacement Device

Lower back pain effects up to 80% of people at some point in their life, a majority of cases being the result of degenerative disc disease. Treatment options for degenerative disc disease are limited, jumping from physical therapy to major spinal fusion and total disc replacement surgery with little to no approaches in between. Furthermore, surgical treatments have not shown to be more effective than conservative treatments and reducing pain and disability over the long term. Hydrogels have shown promise as a potential nucleus pulposus replacement device. Their properties are controllable and can be implanted into the body through minimally evasive routes. In order to successful act as a minimally invasive nucleus pulposus replacement device, the hydrogel must demonstrate an ability to be easily injectable, cure within the body, and restore mechanics once in place.One potential formulation to complete this task is HYDRAFILTM. HYDRAFILTM is a PVA/PEG based hydrogel designed as a nucleus pulposus replacement device. HYDRAFILTM demonstrates thermosetting properties that can be controlled through the use of thermal cycling and holding the material at elevated temperatures until injection. Through various mechanical tests and thermal analyses, HYDRAFILTM demonstrated the ability to cure within the disc and act as a solid implant. After curing HYDRAFILTM exhibits substantial mechanical strength and desired hydration properties

Southwest Research Institute assistance to NASA in biomedical areas of the Technology Utilization program

Technology utilization in biomedical areas, particularly for infants and handicapped person

An Investigation Of The Mechanism Of Traumatic Brain Injury Caused By Blast In The Open Field

Blast-induced traumatic brain injury (bTBI) is a signature wound of modern warfare. The current incomplete understanding of its injury mechanism impedes the development of strategies for effective protection of bTBI. Despite a considerable amount of experimental animal studies focused on the evaluation of brain neurotrauma caused by blast exposure, there is very limited knowledge on the biomechanical responses of the gyrenecephalic brain subjected to primary free-field blast waves imposed in vivo, and the correlation analysis between the biomechanical responses and its injury outcomes. Such information is crucial to the development of injury criteria of bTBI. This study aims to evaluate the external and internal mechanical responses of the brain against different levels of blast loading with Yucatan swine in free field, and to conduct correlational studies with brain tissue damage. To better understand primary bTBI, we have implemented an open field experimental model to apply controlled shock waves on swine head. The applied pressure levels of shock waves were predicted by finite element modeling and verified with calibrated testing. Biomechanical responses of primary blasts such as intracranial pressure (ICP), head kinetics, strain rate of skull, were measured in vivo during the blasts. A positive correlation between incident overpressure (IOP) and its corresponding biomechanical responses of the brain was observed. A parallel group of non-instrumented animals were used to collect injury data 72 hours post experiment. Cellular responses governed by primary blasts, such as neuronal degeneration and apoptosis were studied via immunohistochemistry. Representative fluorescent-stained images were examined under microscope. A positive correlation was found between the amount of degenerative neurons and the blast level. Significant elevation of apoptosis was found in the high-level blast. Comparisons between brains with varies ICP readings demonstrate differences of the numbers of neuronal degeneration and apoptosis within the imaged volume. Additionally, comparisons between sections at different locations of the head did not show spatial changes for cellular responses. These metrics provide a pathway for direct connection between the cellular damage and the measured biomechanical responses of the brain within the same experimental model, and could be critical in understanding the mechanisms of bTBI. This experimental data can be used to validate computer models of bTBI