Dissertations / Theses on the topic 'Implantable medical devices'
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Padera, Robert Francis 1969. "Mass transport in implantable medical devices." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9919.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Whitaker College of Health Sciences and Technology, 1998.Includes bibliographical references (leaves 96-104).
by Robert Francis Padera, Jr.
Ph.D.
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Ash, Sarah L. "Cybersecurity of wireless implantable medical devices." Thesis, Utica College, 2016. http://pqdtopen.proquest.com/#viewpdf?dispub=10109631.
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Wireless implantable medical devices are used to improve and prolong the lives of persons with critical medical conditions. The World Society of Arrhythmias reported that 133,262 defibrillators had been implanted in the United States in 2009 (NBC News, 2012). With the convenience of wireless technology comes the possibility of wireless implantable medical devices being accessed by unauthorized persons with malicious intents. Each year, the Food and Drug Agency (FDA) collects information on medical device failures and has found a substantial increase in the numbers of failures each year (Sametinger, Rozenblit, Lysecky, & Ott, 2015). Mark Goodman, founder of the Future Crimes Institute, wrote an article regarding wireless implantable medical devices (2015). According to Goodman, approximately 300,000 Americans are implanted with wireless implantable medical devices including, but not limited to, cardiac pacemakers and defibrillators, cochlear implants, neurostimulators, and insulin pumps. In upwards of 2.5 million people depend on wireless implantable medical devices to control potential life-threatening diseases and complications. It was projected in a 2012 study completed by the Freedonia Group that the need for wireless implantable medical devices would increase 7.7 percent annually, creating a 52 billion dollar business by 2015 (Goodman, 2015). This capstone project will examine the current cybersecurity risks associated with wireless implantable medical devices. The research will identify potential security threats, current security measures, and consumers’ responsibilities and risks once they acquire the wireless implantable medical devices. Keywords: Cybersecurity, Professor Christopher M. Riddell, critical medical conditions, FDA, medical device failures, risk assessment, wireless networks.
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Roohpour, Nima. "Polyurethane membranes for encapsulation of implantable medical devices." Thesis, Queen Mary, University of London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510793.
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Kod, M. S. "Wireless powering and communication of implantable medical devices." Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3004891/.
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FARINA, MARCO. "Implantable medical devices for drug and cell release." Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2709325.
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This work is focused on the research on how to leverage 3D printing technology in the field of cell transplantation. More specifically, the study of an artificial organ for hormone replacement therapies thanks to the close collaboration between the Methodist Hospital Research Institute, Houston, Texas and Politecnico di Torino, Turin, Italy.
Cell transplantation offers an attractive therapeutic approach for many endocrine deficiencies. Transplanted endocrine cells or engineered cells encapsulated in the here presented 3D printed device, can act as biological sensors detecting changes in hormonal levels and secrete molecules in response to maintain homeostasis.
The major advantage of this technology is that patients affected by endocrine disorder could potentially avoid the need of frequent hormone injections, such as insulin or testosterone, resulting in an improved quality of life and lower chronic side effects associated to external hormone supplementations.
This implant was extensively tested both in vitro and in vivo condition, providing remarkable results that lead to several publications.
The cell encapsulation system was fabricated via 3D printing technology adopting an FDA approved polymeric material. The structure, composed by an array of micro and macro channels, was specifically designed in order to allow vasculature formation within the device and for housing cells while avoiding cell clustering.
Over the course of the Ph.D., the technology was designed, fabricated and tested for the encapsulation of several cell lines and for small and large animal models.
According to the in vivo results, we demonstrated that our 3D printed device exemplifies a clinically translatable strategy for preserving viability and function of transplanted cells. Currently, is ongoing an experiment in Non-Human Primates (data not shown), last pre- clinical study before the possibility to move to the clinical development in humans.
The pre-vascularization approach to achieve an ideal intra-device milieu prior to transplantation, transcutaneous cell loading and refilling capabilities, as well as the
potential for rapid device retrievability, addresses current challenges in transplantation. This technology may offer exciting potential for clinical adoption in relevant medical areas of diabetes, hypogonadism, hypothyroidism, cancer, and neurological diseases among others.
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Saboorideilami, Vafa. "Hospital Purchasing for Implantable Medical Devices: A Triadic Perspective." University of Toledo / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1445269068.
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Cordero, Álvarez Rafael. "Subcutaneous Monitoring of Cardiac Activity for Chronically Implanted Medical Devices." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASS020.
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L'objectif de cette thèse de doctorat est le développement de capteurs et d'algorithmes pour une meilleure surveillance de l'activité cardiaque dans un défibrillateur cardioverteur implantable sous-cutané (S-ICD), et plus précisément pour améliorer la spécificité de détection des tachyarythmies dangereuses telles que la tachycardie ventriculaire (TV) et la fibrillation ventriculaire (FV) dans le S-ICD. Deux schémas de détection TV/FV indépendants ont été développés dans ce but : l'un de nature électrophysiologique et l'autre hémodynamique. Le schéma de détection électrophysiologique repose sur un ECG spécial qui a été enregistré le long d'un dipôle «court» situé au-dessus du grand pectoral inférieur gauche. Ce dipôle court maximise le rapport R/T et le rapport signal/bruit chez 9 volontaires sains. En théorie, cela devrait réduire le risque de détections faussement positives de TV/ FV simplement en raison de la taille, de l'emplacement et de l'orientation du dipôle, indépendamment de toute autre méthode de traitement du signal. Le schéma de détection hémodynamique repose quant à lui sur les vibrations cardiaques enregistrées par deux prototypes de capteurs accéléromètres triaxiaux. Les vibrations cardiaques sous-cutanées mesurées ont été caractérisées, validées physiologiquement et optimisées via leur filtrage le long de bandes passantes spécifiques et leur projection le long d'un référentiel spécifique patient. Le premier algorithme au monde indépendant de détection de FV par vibration cardiaque a été développé en opérant sur ces signaux optimisés. Les mêmes prototypes d'accéléromètre se sont également avérés capables d'enregistrer des accélérations respiratoires et de détecter l'apnée. Enfin, un dernier prototype de sonde sous-cutanée composite, composé de trois électrodes, d'un accéléromètre bi-axial et de connecteurs d'appareil standard. Ce prototype est capable d'enregistrer l'ECG dipolaire court, les vibrations cardiaques et les accélérations respiratoires. Cette sonde prototype a été implantée dans un quatrième et dernier animalThe aim of this doctoral thesis was the development of sensors and algorithms for the improved monitoring of cardiac activity in the subcutaneous implantable cardioverter-defibrillator (SICD). More precisely, to improve the detection specificity of dangerous tachyarrhythmia such as ventricular tachycardia (VT) and ventricular fibrillation (VF). Two independent VT/VF detection schemes were developed for this: one electrophysiological in nature, and the other hemodynamic. The electrophysiological sensing scheme relied on a special ECG that was recorded along a short dipole located above the lower left pectoralis major. This short dipole maximised R/T ratio and signal-to-noise ratio in a total of 9 healthy volunteers. In theory, it will reduce the risk of false positive VT/VF detections simply by consequence of the dipole size, location, and orientation and independently of any further signal processing methods. The hemodynamic sensing scheme relied on cardiac vibrations recorded from two tri-axial accelerometer prototype sensors. These subcutaneous cardiac vibrations were characterised, physiologically validated, and optimised via their filtering along specific bandwidths and projection along a patient specific reference frame. The world’s first independent cardiac vibration VF detection algorithm was developed operating on these optimised signals. The same accelerometer prototypes were also shown to be able to record respiratory accelerations and detect apnoea. A final subcutaneous lead prototype was developed capable of recording the short dipole ECG, cardiac vibrations, and respiratory accelerations. It consisted of three electrodes, a bi-axial accelerometer, and industry-standard device connectors. The prototype lead was implanted in a fourth and final animal
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Svensson, Andreas. "Design of Inductive Coupling for Powering andCommunication of Implantable Medical Devices." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-105112.
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Technological advances over the years have made it possible to reduce the size and power consumption of electronics. This has led to significant advances for biomedical sensors. It is now possible to reduce the size enough to create implantable sensors. This type of sensors can for instance be used to measure the glucose level of diabetes patients. An implantable sensor can significantly simplify the measurement procedure. Taking a measurement can be as simple as turning on a device, capable of receiving the data sent by the sensor. Unfortunately, the lifetime of this type of sensors can be limited by the battery of the implanted sensor. To improve the lifetime, the battery has to be replaced. Instead of a battery, energy harvesting can be used. One promising such method is to transfer power from outside the body to the implanted sensor. This thesis focuses on one such way, inductive coupling. Inductive coupling, can be used both to transfer power from an external device to the sensor, and to transfer data from the sensor to the external device. In this thesis a system for wireless power transfer has been proposed. The system is based on state of the art circuits for inductive powering and communication, for implantable devices. The system is adapted for powering an implantable biomedical sensor including a PIC16LF1823 microcontroller. The system includes asynchronous serial communication, from the microcontroller in the implantable device to the external reader device using load shift keying. The external device of the system, has been implemented in two different versions, one using a printed circuit board (PCB), and one simplified version using a breadboard. The implantable device has been implemented in three different versions, one on a PCB, one simplified version using a breadboard and finally one application specific integrated circuit (ASIC). All three implementations of the implantable devices use a resistor to simulate the power consumption of an actual biomedical sensor. The ASIC implementation contains only the parts needed for receiving power and transmitting data. The ASIC was designed using a 150nm CMOS process. The PCB implementations of both devices have been used to measure the system performance. The maximum total power consumption was found to be 107 mW, using a 5 V supply voltage. The maximum distance for powering the implantable device was found to be 4.5 cm in air. The sensor, including the microcontroller, is provided with 648 μW of power at the maximum distance. A raw data rate of 19200 bit/s has been used successfully to transfer data. Additionally, oscilloscope measurements indicates that a data rate close to 62500 bit/s could be possible. Simulations of the proposed ASIC show that the minimum total voltage drop from the received AC voltage to the regulated output voltage is 430 mV. This is much smaller than for the PCB implementation. The reduced voltage drop will reduce the power dissipation of the implantable device and increase the maximum possible distance between the external device and the implanted devices. The ASIC can provide 648 μW of power at a coupling coefficient k=0.0032.Tekniska framsteg genom åren har gjort det möjligt att minska storleken och effektforbrukningen hos elektronik. Detta har lett till stora framsteg för biomedicinska sensorer. Det är nu möjligt att tillverka elektronik liten nog att användas i sensor implantat. En sådan sensor skulle till exempel kunna användas for att mäta glukos värden i blodet hos diabetes patienter. Ett sådant Implantat kan forenkla mätningar, genom att endast en mottagare behövs for att kunna få mätvarden från sensorn. Livslängden för denna typ av sensor kan forbättras genom att undvika att använda ett batteri som energikalla. Istället kan energin överföras från en apparat utanför kroppen till implantatet. Denna rapport handlar om ett sadant sätt, namligen induktiv energiöverföring. Denna teknik kan användas både till att överfora energi till implantatet, och till att överfora data från implantatet till den externa enheten. I den har rapporten beskrivs ett system for tradlös energiöverforing. Systemet ar baserat på den senaste tekniken for induktiv överforing, och har anpassats for att förse en sensor som inkluderar en PIC16LF1823 mikrokontroller. Systemet inkluderar också asynkron seriell kommunikation från mikrokontrollern i implantatet till den externa enheten genom att använda lastmodulering. Den externa enheten har implementerats i två versioner. En full version på ett kretskort, samt en förenklad version pa ett kopplingsdäck. Tre versioner av kretsarna for implantatet har använts, en förenklad version på ett kopplingsdäck, en version på kretskort och en applikations specifik integrerad krets. Den applikations specifika integrerade kretsen har simulerats med modeller från en 150 nm CMOS tillverkningsprocess, medans de andra versionerna har konstruerats av diskreta komponenter och använts för mätningar. Mätresultat från kretskortsimplementationen visar på en maximal räckvidd pa cirka 4,5 cm i luft, med en total effektforbrukning pa 107 mW. Vid det maximala rakvidden mottags 648 μW. En dataöverföringshastighet pa 19200 bitar/s har uppnåtts med kretskorts versionen. Mätningar med oscilloskop visar att det kan vara möjligt att öka överforingshastigheten till 62500 bitar/s. Simuleringsresultat for den integrerade kretsen visar att det lägsta spänningsfallet från den mottagna växelspanningen till den reglerade likspänningen är 430 mV. Detta ar betydligt mindre for den integrerade kretsen än för kretskorts versionen, vilket resulterar i en lagre effektforbrukning och troligen en längre räckvidd för systemet. Den integrerade kretsen kan leverera 648 μW vid en kopplingsfaktor pa k=0.0032.
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Kiani, Mehdi. "Wireless power and data transmission to high-performance implantable medical devices." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53396.
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Novel techniques for high-performance wireless power transmission and data interfacing with implantable medical devices (IMDs) were proposed. Several system- and circuit-level techniques were developed towards the design of a novel wireless data and power transmission link for a multi-channel inductively-powered wireless implantable neural-recording and stimulation system. Such wireless data and power transmission techniques have promising prospects for use in IMDs such as biosensors and neural recording/stimulation devices, neural interfacing experiments in enriched environments, radio-frequency identification (RFID), smartcards, near-field communication (NFC), wireless sensors, and charging mobile devices and electric vehicles. The contributions in wireless power transfer are the development of an RFID-based closed-loop power transmission system, a high-performance 3-coil link with optimal design procedure, circuit-based theoretical foundation for magnetic-resonance-based power transmission using multiple coils, a figure-of-merit for designing high-performance inductive links, a low-power and adaptive power management and data transceiver ASIC to be used as a general-purpose power module for wireless electrophysiology experiments, and a Q-modulated inductive link for automatic load matching. In wireless data transfer, the contributions are the development of a new modulation technique called pulse-delay modulation for low-power and wideband near-field data communication and a pulse-width-modulation impulse-radio ultra-wideband transceiver for low-power and wideband far-field data transmission.
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Al-Hassanieh, Haitham (Haitham Zuhair). "Encryption on the air : non-Invasive security for implantable medical devices." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/66020.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 73-78).
Modern implantable medical devices (IMDs) including pacemakers, cardiac defibrillators and nerve stimulators feature wireless connectivity that enables remote monitoring and post-implantation adjustment. However, recent work has demonstrated that flawed security tempers these medical benefits. In particular, an understandable lack of cryptographic mechanisms results in the IMD disclosing private data and being unable to distinguish authorized from unauthorized commands. In this thesis, we present IMD-Shield; a prototype defenses against a previously proposed suite of attacks on IMDs. IMD-Shield is an external entity that uses a new full dulpex radio design to secure transmissions to and from the IMD on the air wihtout incorporating the IMD itself. Because replacing the install base of wireless-enabled IMDs is infeasible, our system non-invasively enhances the security of unmodified IMDs. We implement and evaluate our mechanism against modern IMDs in a variety of attack scenarios and find that it effectively provides confidentiality for private data and shields the IMD from unauthorized commands.
by Haitham Al-Hassanieh.
S.M.
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Yip, Marcus. "Ultra-low-power circuits and systems for wearable and implantable medical devices." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/84902.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2013.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 219-231).
Advances in circuits, sensors, and energy storage elements have opened up many new possibilities in the health industry. In the area of wearable devices, the miniaturization of electronics has spurred the rapid development of wearable vital signs, activity, and fitness monitors. Maximizing the time between battery recharge places stringent requirements on power consumption by the device. For implantable devices, the situation is exacerbated by the fact that energy storage capacity is limited by volume constraints, and frequent battery replacement via surgery is undesirable. In this case, the design of energy-efficient circuits and systems becomes even more crucial. This thesis explores the design of energy-efficient circuits and systems for two medical applications. The first half of the thesis focuses on the design and implementation of an ultra-low-power, mixed-signal front-end for a wearable ECG monitor in a 0.18pm CMOS process. A mixed-signal architecture together with analog circuit optimizations enable ultra-low-voltage operation at 0.6V which provides power savings through voltage scaling, and ensures compatibility with state-of-the-art DSPs. The fully-integrated front-end consumes just 2.9[mu]W, which is two orders of magnitude lower than commercially available parts. The second half of this thesis focuses on ultra-low-power system design and energy-efficient neural stimulation for a proof-of-concept fully-implantable cochlear implant. First, implantable acoustic sensing is demonstrated by sensing the motion of a human cadaveric middle ear with a piezoelectric sensor. Second, alternate energy-efficient electrical stimulation waveforms are investigated to reduce neural stimulation power when compared to the conventional rectangular waveform. The energy-optimal waveform is analyzed using a computational nerve fiber model, and validated with in-vivo ECAP recordings in the auditory nerve of two cats and with psychophysical tests in two human cochlear implant users. Preliminary human subject testing shows that charge and energy savings of 20-30% and 15-35% respectively are possible with alternative waveforms. A system-on-chip comprising the sensor interface, reconfigurable sound processor, and arbitrary-waveform neural stimulator is implemented in a 0.18[mu]m high-voltage CMOS process to demonstrate the feasibility of this system. The sensor interface and sound processor consume just 12[mu]W of power, representing just 2% of the overall system power which is dominated by stimulation. As a result, the energy savings from using alternative stimulation waveforms transfer directly to the system.
by Marcus Yip.
Ph.D.
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Mirbozorgi, Seyed Abdollah. "High-performance wireless power and data transfer interface for implantable medical devices." Doctoral thesis, Université Laval, 2015. http://hdl.handle.net/20.500.11794/26209.
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D’importants progès ont été réalisés dans le développement des systèmes biomédicaux implantables grâce aux dernières avancées de la microélectronique et des technologies sans fil. Néanmoins, ces appareils restent difficiles à commercialier. Cette situation est due particulièrement à un manque de stratégies de design capable supporter les fonctionnalités exigées, aux limites de miniaturisation, ainsi qu’au manque d’interface sans fil à haut débit fiable et faible puissance capable de connecter les implants et les périphériques externes. Le nombre de sites de stimulation et/ou d’électrodes d’enregistrement retrouvés dans les dernières interfaces cerveau-ordinateur (IMC) ne cesse de croître afin d’augmenter la précision de contrôle, et d’améliorer notre compréhension des fonctions cérébrales. Ce nombre est appelé à atteindre un millier de site à court terme, ce qui exige des débits de données atteingnant facilement les 500 Mbps. Ceci étant dit, ces travaux visent à élaborer de nouvelles stratégies innovantes de conception de dispositifs biomédicaux implantables afin de repousser les limites mentionnées ci-dessus. On présente de nouvelles techniques faible puissance beaucoup plus performantes pour le transfert d’énergie et de données sans fil à haut débit ainsi que l’analyse et la réalisation de ces dernières grâce à des prototypes microélectroniques CMOS. Dans un premier temps, ces travaux exposent notre nouvelle structure multibobine inductive à résonance présentant une puissance sans fil distribuée uniformément pour alimenter des systèmes miniatures d’étude du cerveaux avec des models animaux en ilberté ainsi que des dispositifs médicaux implantbles sans fil qui se caractérisent par une capacité de positionnement libre. La structure propose un lien de résonance multibobines inductive, dont le résonateur principal est constitué d’une multitude de résonateurs identiques disposés dans une matrice de bobines carrées. Ces dernières sont connectées en parallèle afin de réaliser des surfaces de puissance (2D) ainsi qu’une chambre d’alimentation (3D). La chambre proposée utilise deux matrices de résonateurs de base, mises face à face et connectés en parallèle afin d’obtenir une distribution d’énergie uniforme en 3D. Chaque surface comprend neuf bobines superposées, connectées en parallèle et réailsées sur une carte de circuit imprimé deux couches FR4. La chambre dispose d’un mécanisme naturel de localisation de puissance qui facilite sa mise en oeuvre et son fonctionnement. En procédant ainsi, nous évitons la nécessité d’une détection active de l’emplacement de la charge et le contrôle d’alimentation. Notre approche permet à cette surface d’alimentation unique de fournir une efficacité de transfert de puissance (PTE) de 69% et une puissance délivrée à la charge (PDL) de 120 mW, pour une distance de séparation de 4 cm, tandis que le prototype de chambre complet fournit un PTE uniforme de 59% et un PDL de 100 mW en 3D, partout à l’intérieur de la chambre avec un volume de chambre de 27 × 27 × 16 cm3. Une étape critique avant d’utiliser un dispositif implantable chez les humains consiste à vérifier ses fonctionnalités sur des sujets animaux. Par conséquent, la chambre d’énergie sans fil conçue sera utilisée afin de caractériser les performances d’ une interface sans fil de transmisison de données dans un environnement réaliste in vivo avec positionement libre. Un émetteur-récepteur full-duplex (FDT) entièrement intégré qui se caractérise par sa faible puissance est conçu pour réaliser une interfaces bi-directionnelles (stimulation et enregistrement) avec des débits asymétriques: des taux de tramnsmission plus élevés sont nécessaires pour l’enregistrement électrophysiologique multicanal (signaux de liaison montante) alors que les taux moins élevés sont utilisés pour la stimulation (les signaux de liaison descendante). L’émetteur (TX) et le récepteur (RX) se partagent une seule antenne afin de réduire la taille de l’implant. L’émetteur utilise la radio ultra-large bande par impulsions (IR-UWB) basée sur l’approche edge combining et le RX utilise la bande ISM (Industrielle, Scientifique et Médicale) de fréquence central 2.4 GHz et la modulation on-off-keying (OOK). Une bonne isolation (> 20 dB) est obtenue entre le TX et le RX grâce à 1) la mise en forme les impulsions émises dans le spectre UWB non réglementée (3.1-7 GHz), et 2) le filtrage espace-efficace (évitant l’utilisation d’un circulateur ou d’un diplexeur) du spectre du lien de communication descendant directement au niveau de l’ amplificateur à faible bruit (LNA). L’émetteur UWB 3.1-7 GHz utilise un e modultion OOK ainsi qu’une modulation par déplacement de phase (BPSK) à seulement 10.8 pJ / bits. Le FDT proposé permet d’atteindre 500 Mbps de débit de données en lien montant et 100 Mbps de débit de données de lien descendant. Il est entièrement intégré dans un procédé TSMC CMOS 0.18 um standard et possède une taille totale de 0.8 mm2. La consommation totale d’énergie mesurée est de 10.4 mW (5 mW pour RX et 5.4 mW pour TX au taux de 500 Mbps).In recent years, there has been major progress on implantable biomedical systems that support most of the functionalities of wireless implantable devices. Nevertheless, these devices remain mostly restricted to be commercialized, in part due to weakness of a straightforward design to support the required functionalities, limitation on miniaturization, and lack of a reliable low-power high data rate interface between implants and external devices. This research provides novel strategies on the design of implantable biomedical devices that addresses these limitations by presenting analysis and techniques for wireless power transfer and efficient data transfer. The first part of this research includes our proposed novel resonance-based multicoil inductive power link structure with uniform power distribution to wirelessly power up smart animal research systems and implanted medical devices with high power efficiency and free positioning capability. The proposed structure consists of a multicoil resonance inductive link, which primary resonator array is made of several identical resonators enclosed in a scalable array of overlapping square coils that are connected in parallel and arranged in power surface (2D) and power chamber (3D) configurations. The proposed chamber uses two arrays of primary resonators, facing each other, and connected in parallel to achieve uniform power distribution in 3D. Each surface includes 9 overlapped coils connected in parallel and implemented into two layers of FR4 printed circuit board. The chamber features a natural power localization mechanism, which simplifies its implementation and eases its operation by avoiding the need for active detection of the load location and power control mechanisms. A single power surface based on the proposed approach can provide a power transfer efficiency (PTE) of 69% and a power delivered to the load (PDL) of 120 mW, for a separation distance of 4 cm, whereas the complete chamber prototype provides a uniform PTE of 59% and a PDL of 100 mW in 3D, everywhere inside the chamber with a chamber size of 27×27×16 cm3. The second part of this research includes our proposed novel, fully-integrated, low-power fullduplex transceiver (FDT) to support bi-directional neural interfacing applications (stimulating and recording) with asymmetric data rates: higher rates are required for recording (uplink signals) than stimulation (downlink signals). The transmitter (TX) and receiver (RX) share a single antenna to reduce implant size. The TX uses impulse radio ultra-wide band (IR-UWB) based on an edge combining approach, and the RX uses a novel 2.4-GHz on-off keying (OOK) receiver. Proper isolation (> 20 dB) between the TX and RX path is implemented 1) by shaping the transmitted pulses to fall within the unregulated UWB spectrum (3.1-7 GHz), and 2) by space-efficient filtering (avoiding a circulator or diplexer) of the downlink OOK spectrum in the RX low-noise amplifier (LNA). The UWB 3.1-7 GHz transmitter using OOK and binary phase shift keying (BPSK) modulations at only 10.8 pJ/bit. The proposed FDT provides dual band 500 Mbps TX uplink data rate and 100 Mbps RX downlink data rate. It is fully integrated on standard TSMC 0.18 nm CMOS within a total size of 0.8 mm2. The total power consumption measured 10.4 mW (5 mW for RX and 5.4 mW for TX at the rate of 500 Mbps).
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Satya, Sarina. "ST Monitoring on the Programmer for Implantable Cardioverter Devices." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/258.
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Cardiovascular disease is one of the most prevalent causes of death which has a high mortality rate. If identified early and treated appropriately, the mortality in patients with cardiovascular disease can be hugely reduced. For several decades, 12-Lead ECG has been the standard technique used to identify ischemia, and recent studies have shown that intracardiac electrogram has many benefits over external monitoring such as holter. ST Monitoring feature has been added to St. Jude Medical intracardiac cardioverter defibrillators (ICD) to leverage the ECG technology for identifying cardiovascular disease. This algorithm monitors the intracardiac electrogram to detect and report patterns which could be related to ischemic events. This feature is expected to enhance the process of identifying ischemia and infarction, and provides long-term management of the disease.
In order to support the new implantable devices with ST Monitoring capability, the programmer software was updated to support this new feature in the device. This thesis discusses the work on the programmer. Chapter 1 begins with a background of how monitoring technology in an implantable device can benefit the patients facing high risk of myocardial infarction. Chapter 2 states the objective for the work on the programmer. Chapter 3 describes the implementation and the application of this feature. Conclusion and future development are discussed in Chapter 5.
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Du, Toit Hendrik. "Development of miniature enzymatic biofuel cells as potential power sources for implantable medical devices." Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.642054.
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Since the first implantation of a cardiac pacemaker numerous efforts have been made to develop miniature implantable power devices, which would be able to run continuously for long periods of time without the need for replacement. In this context enzymatic biofuel cells (EBFCs) represent an attractive alternative, as they work at body temperature, are light and easy to miniaturise. Additionally, enzymatic biofuel cells can generate energy from the metabolites already present in physiological fluids, and produce waste products that naturally occur in the human body. With a view to improving the biocompatibility of such devices, the use of highly porous gold (hPG) as a non-toxic high surface area alternative to the carbon nanotube based materials currently used was here investigated. The process for directly depositing hPG onto conductive surfaces was further developed to improve the stability of the deposited hPG films. The possibility of depositing these films on a range of different materials was also investigated. In particular it was shown that hPG films could also be deposited on very low cost materials, such as graphite composites. It was also demonstrated that these hPG electrodes exhibited potential for the direct electro-oxidation of aldehyde group containing sugars. The potential use of hPG electrodes as abiotic glucose sensors was consequently investigated and found to give stable amperometric responses between 0 and 50 mM, with a strong glucose dependant response even at the lowest concentration investigated of 0.5 µM. However, since hPG electrodes were found to be susceptible to a large degree of interference and fouling in biological solutions, the use of glucose oxidase (GOx) on hPG electrodes was investigated in order to increase the specificity and stability of such electrodes in biological systems. A rapid and simple technique for the direct and functional deposition of GOx onto hPG was developed without using foreign electron mediators. These hPG-GOx electrodes were found to act as glucose sensors with extremely high sensitivity (22.7 µA mM-1 cm-2), and a linear response to glucose in a range of between 50 μM and10 mM. Finally EBFCs that exhibit continuous flow through were developed using fast prototyping techniques that employ 3D printed moulds. These EBFCs employed hPG-GOx electrodes coupled with hPG and laccase electrodes in order to generate power from glucose. The continuous and stable power production from a flow through EBFC for up to 30 days was subsequently demonstrated for the first time, with a peak power output of approximately 2 µW.
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Jow, Uei-Ming. "A multiband inductive wireless link for implantable medical devices and small freely behaving animal subjects." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/51930.
Full textAbstract:
The objective of this research is to introduce two state-of-the-art wireless biomedical systems: (1) a multiband transcutaneous communication system for implantable microelectronic devices (IMDs) and (2) a new wireless power delivery system, called the “EnerCage,” for experiments involving freely-behaving animals. The wireless multiband link for IMDs achieves power transmission via a pair of coils designed for maximum coupling efficiency. The data link is able to handle large communication bandwidth with minimum interference from the power-carrier thanks to its optimized geometry. Wireless data and power links have promising prospects for use in biomedical devices such as biosensors, neural recording, and neural stimulation devices. The EnerCage system includes a stationary unit with an array of coils for inductive power transmission and three-dimensional magnetic sensors for non-line-of-sight tracking of animal subjects. It aims to energize novel biological data-acquisition and stimulation instruments for long-term experiments, without interruption, on freely behaving small animal subjects in large experimental arenas. The EnerCage system has been tested in one-hour in vivo experiment for wireless power and data communication, and the results show the feasibility of this system. The contributions from this research work are summarized as follows: 1. Development of an inductive link model. 2. Development of an accurate PSC models, with parasitic effects for implantable devices. 3. Proposing the design procedure for the inductive link with optimal physical geometry to maximize the PTE. 4. Design of novel antenna and coil geometry for wireless multiband link: power carrier, forward data link, and back telemetry. 5. Development of a model of overlapping PSCs, which can create a homogenous magnetic in a large experimental area for wireless power transmission at a certain coupling distance. 6. Design and optimization for multi-coil link, which can provide optimal load matching for maximum PTE. 7. Design of the wireless power and data communication system for long-term animal experiments, without interruption, on freely behaving small animal subjects in any shape of experimental arenas.
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Perez, Samuel. "Integration and Cross-Coupling of a Notched-Turbine Symbiotic Power Source for Implantable Medical Devices." Scholar Commons, 2018. http://scholarcommons.usf.edu/etd/7215.
Full textAbstract:
The purpose of this research is to design and integrate a symbiotic notched-turbine energy generator for implantation as a cross-coupled system capable of continuously and perpetually powering an electronic implantable medical device (IMD), which is a device designed to operate inside the body of a higher mammal to enhance, correct or provide the body with a function that has deviated from the norm or has stopped altogether. The list of IMDs available for implantation keeps growing every year, one of the newest being the VBLOC, produced by EnteroMedics®, and approved by the Food and Drug Administration (FDA) on January 15th, 2015[1], [2] to treat obesity in the United States, in lieu of the more dangerous and costly bariatric surgery widely used to treat the same condition. Some of the more traditional IMDs, such as the cardiac defibrillator, pacemaker, and insulin pumps require the use of a battery system for their operation.
The powering of IMDs is a topic of growing importance and as such, the energy released by the hydrodynamic action of the cardiovascular system of a higher mammal is presented in this work as a source of energy that can be converted into electricity by use of a microturbine, loaded with magnetic rings that induce a time-varying magnetic field onto a set of insulated coils through the process of electromagnetic induction (EMI) in accordance with Faraday’s Law.
This work goes beyond mere power production and focuses on the process required to integrate this power source with an IMD when it is coupled to the cardiovascular system for drawing hydro-mechanical power for conversion to electricity and to the IMD of choice to
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deliver the conditioned power, thus replicating a symbiotic process. The harvested energy in the form of a time-varying tri-phase sine wave is therefore rectified, conditioned and made available for use to the IMD.
The proposed 3-phase generator has a volume of 1.02 cm3 and has the potential to be implemented as a dual or quad system that doubles or quadruples the single generator power capabilities accordingly. The rectifying and conditioning circuits may be housed in a hermetically sealed container, covered with a biocompatible material such as, ultra-high molecular weight polyethylene (UHMWPE), polymethylmethacrylate (PMMA) or titanium, which can afford the best implantation properties such as non-absorbability, durability, hardness, and biocompatibility [4]. Additionally, the prevention of blood clotting is of paramount importance in any IMD, which can be helped, for example by treating its surface with Tethered-Liquid Perfluorocarbons (TLP) to prevent biofilm formation of the blood that typically leads to infections and clotting[5].
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Molosky, Vincent. "The Influence of Identifiable Personality Traits on Nurses’ Intention to Use Wireless Implantable Medical Devices." Diss., NSUWorks, 2019. https://nsuworks.nova.edu/gscis_etd/1078.
Full textAbstract:
Technically-driven medical devices such as wireless implantable medical devices (WIMD) have become ubiquitous within healthcare. The use of these devices has changed the way nurses administer patient care. Consequently, the nursing workforce is large and diverse, and with it comes an expected disparity in personalities. Research involving human factors and technology acceptance in healthcare is not new. Yet due to the changing variables in the manner of which patient care is being administered, both in person and in the mechanism of treatment, recent research suggests that individual human factors such as personality traits may hold unknown implications involving more successful adoption of emerging technologies for patient care.
The purpose of this research was to empirically investigate the influence of personality traits on a nurse’s intention to use WIMDs for patient care. One hundred and two nurses from a tertiary teaching hospital in Michigan were surveyed to determine if their identifiable personality traits statistically related to their intention to use a WIMD. A predictive model was developed by combining constructs from the unified theory of acceptance and use of technology (UTAUT) model and the Five Factor personality trait model (FFM). The model used moderated multiple regression (MMR) to statistically identify if the personality traits of openness, conscientiousness, extraversion, agreeableness, and neuroticism, moderated one or more statistically significant relationships between 1) performance expectancy (PE) and intention to use (IU), 2) effort expectancy (EE) and IU, 3) and social influence (SI) and IU. It was predicted that PE, EE, and SI would show statistical significance on a nurse’s IU of a WIMD when moderated by one or more of the five personality traits. Results showed statistical significance between PE and IU, and EE and IU, but not between SI and IU, when moderated by extraversion. Results showed no statistical significance between PE and IU, EE and IU, or SI and IU when moderated by openness, conscientiousness, agreeableness, or neuroticism.
This research has contributed by conducting an investigation on individual human factors that may impact nurses’ intention to use emerging technologies; and by providing statistical evidence that may help to better predict the role personality traits have on a nurse’s adoption of WIMDs for patient care.
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Do, Khoa Tat. "Universal Engineering Programmer - An In-house Development Tool For Developing and Testing Implantable Medical Devices In St. Jude Medical." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/488.
Full textAbstract:
During development and testing of the functionality of the pacemaker and defibrillator device, engineers in the St. Jude Medical Cardiac Rhythm Management Division use an in-house development tool called Universal Engineering Programmer (UEP) to ensure the device functions as expected, before it can be used to test on an animal or a human during the implantation process. In addition, some applications of UEP are incorporated into the official releases of the device product. UEP has been developed and used by engineers across departments in the St. Jude Medical Cardiac Rhythm Management Division (CRMD). This thesis covers the flexible and reusable design and implementation of UEP features, to allow engineers to easily and effectively develop and test the devices.
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Park, Yong J. "STT EVENT STREAM FEATURE TO ASSIST SOFTWARE TESTING OF IMPANTABLE DEVICES IN ST. JUDE MEDICAL." DigitalCommons@CalPoly, 2009. https://digitalcommons.calpoly.edu/theses/49.
Full textAbstract:
During development and testing of the pacemaker and defibrillator device functionality, engineers in the cardiac rhythm management industry use a patient simulator to ensure device functionality properly before device is tested with an animal or a human. The patient simulator is also used in the formal device product testing. In St. Jude Medical, a patient simulator called Simulation Test Tool (STT) has been developed and used by engineers in the company. While the Heart Simulator (HS) feature based on physiological heart model in the STT has been served as a main cardiac rhythm simulation feature, there has been an increasing need of a new feature in the STT for engineers to create heart rhythm scenarios more easily and effectively. This thesis covers the design and implementation of the new STT feature, called Event Stream, which allows users to create heart rhythm scenarios using simple text string based syntax for testing device functionality.
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Wu, Longfei. "Designing Effective Security and Privacy Schemes for Wireless Mobile Devices." Diss., Temple University Libraries, 2017. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/469736.
Full textAbstract:
Computer and Information SciencePh.D.
The growing ubiquity of modern wireless and mobile electronic devices has brought our daily lives with more convenience and fun. Today's smartphones are equipped with a variety of sensors and wireless communication technologies, which can support not only the basic functions like phone call and web browsing, but also advanced functions like mobile pay, biometric security, fitness monitoring, etc. Internet-of-Things (IoT) is another category of popular wireless devices that are networked to collect and exchange data. For example, the smart appliances are increasingly deployed to serve in home and office environments, such as smart thermostat, smart bulb, and smart meter. Additionally, implantable medical devices (IMD) is the typical type of modern wireless devices that are implanted within human body for diagnostic, monitoring, and therapeutic purposes. However, these modern wireless and mobile devices are not well protected compared with traditional personal computers (PCs), due to the intrinsic limitations in computation power, battery capacity, etc. In this dissertation, we first present the security and privacy vulnerabilities we discovered. Then, we present our designs to address these issues and enhance the security of smartphones, IoT devices, and IMDs. For smartphone security, we investigate the mobile phishing attacks, mobile clickjacking attacks and mobile camera-based attacks. Phishing attacks aim to steal private information such as credentials. We propose a novel anti-phishing scheme MobiFish, which can detect both phishing webpages and phishing applications (apps). The key idea is to check the consistency between the claimed identity and the actual identity of a webpage/app. The claimed identity can be extracted from the screenshot of login user interface (UI) using the optical character recognition (OCR) technique, while the actual identity is indicated by the secondary-level domain name of the Uniform Resource Locator (URL) to which the credentials are submitted. Clickjacking attacks intend to hijack user inputs and re-route them to other UIs that are not supposed to receive them. To defend such attacks, a lightweight and independent detection service is integrated into the Android operating system. Our solution requires no user or app developer effort, and is compatible with existing commercial apps. Camera-based attacks on smartphone can secretly capture photos or videos without the phone user's knowledge. One advanced attack we discovered records the user's eye movements when entering passwords. We found that it is possible to recover simple passwords from the video containing user eye movements. Next, we propose an out-of-band two-factor authentication scheme for indoor IoT devices (e.g., smart appliances) based on the Blockchain infrastructure. Since smart home environment consists of multiple IoT devices that may share their sensed data to better serve the user, when one IoT device is being accessed, our design utilizes another device to conduct a secondary authentication over an out-of-band channel (light, acoustic, etc.), to detect if the access requestor is a malicious external device. Unlike smartphones and IoT devices, IMDs have the most limited computation and battery resources. We devise a novel smartphone-assisted access control scheme in which the patient's smartphone is used to delegate the heavy computations for authentication and authorization. The communications between the smartphone and the IMD programmer are conducted through an audio cable, which can resist the wireless eavesdropping and other active attacks.
Temple University--Theses
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Rizzo, Giulia. "Study of a MagnetoElectric Transducer to Wireless Power Medical Implants." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPAST012.
Full textAbstract:
Actuellement, le marché des implants offre milliers de dispositifs différents pour diagnostiquer, traiter et suivre le patient. Dans la dernière décennie, d'importants travaux de recherche ont permis de rendre les dispositifs implantés plus durables et moins invasifs. La source d'énergie la plus utilisée reste néanmoins la pile électrochimique à usage unique. Pour un implant à long terme, il est nécessaire de remplacer la pile déchargée, ce qui nécessite une intervention chirurgicale coûteuse et invasive. Pour résoudre ces problèmes, deux approches ont été récemment proposées, la première consiste à utiliser l'énergie biomécanique du corps, et la deuxième consiste à transmettre de l'énergie depuis l'extérieur du corps humain. Dans le premier cas, par exemple, il est possible d'alimenter la nouvelle génération de pacemaker avec un MEMS piézoélectrique en utilisant l’énergie mécanique fournie par les battements cardiaques. Dans le deuxième cas, la télé-alimentation par induction entre deux bobines (l'une dans l'implant, l'autre à l'extérieur du corps) est une technologie de plus en plus répandue dans le secteur biomédical. Une différence importante entre ces deux techniques concerne les niveaux de puissance atteints : quelques µW pour la récupération d'énergie, et de quelques mW au W pour la télé-alimentation. Durant cette thèse, une nouvelle technologie de télé-alimentation a été développée. Le système considéré est constitué de deux blocs principaux, l'émetteur (situé à l’extérieur du corps) et le récepteur (situé dans l'implant). L'émetteur est constitué d’une bobine, sur laquelle il y a peu de contraintes en termes de taille et de position sur le corps. Le récepteur est un transducteur magnétoélectrique (ME). L’utilisation de ce système ME est notamment motivée par la possibilité de s’affranchir -au moins en partie- des contraintes d'alignement du système classique de bobine-bobine, alignement difficile à assurer dans le cas des dispositifs implantables. Le transducteur ME considéré est un composite constitué de matériaux piézoélectriques et magnétostrictifs. L’élément magnétostrictif a la propriété de se déformer mécaniquement, lorsqu'il est exposé à un champ magnétique. L’élément piézoélectrique se polarise et crée un champ électrique sous l’effet d’une contrainte mécanique. Ainsi, lorsque la bobine émettrice génère un champ magnétique, à la résonance, elle crée une déformation élastique du matériau magnétostrictif. Cette déformation mécanique est transmise à la couche piézoélectrique, dans laquelle apparaît un champ électrique, générant ainsi une tension électrique. Grâce à cette conversion magnéto-mécano-électrique, l'implant médical peut être alimenté ou rechargé. Pendant cette thèse, des transducteurs de différentes dimensions ont été réalisés et testés : 10mm et 16mm de diamètre, et de 2 à 5 mm d’épaisseur. Parmi de nombreux résultats de caractérisation, un résultat très intéressant montre qu’à diamètre égal les transducteurs les plus minces avec une fraction volumique de matériau magnétostrictif plus importante permettent d’atteindre des puissances plus importantes qu’avec des échantillons plus épais et dont la fraction volumique de matériau magnétostrictif plus faible. Ce résultat ouvre d’intéressantes perspectives pour la miniaturisation de transducteurs ME tout en conservant une efficacité satisfaisante dans le transfert d'énergie. Concernant les tests in vitro, les résultats obtenus sont très prometteurs, montrant des puissances suffisantes pour recharger un implant jusqu'à 20 mm de distance de la bobine émettrice, dans l'orientation la plus défavorable. Un tel résultat est impossible à obtenir dans le cas d’un système bobine-bobine dans la position la plus défavorable (bobines perpendiculaires).En conclusion, les résultats obtenus présentent des perspectives très intéressantes pour la télé-alimentation, en termes de dispositifs miniaturisés et d'adaptabilité à la localisation des dispositifs médicaux implantésNowadays, the market of implantable medical devices is very large and heterogeneous: of the order of 4,000 different device types tracked by the FDA in 2018 that can diagnose, monitor, and treat patients. Over the past decades, significant research has made to develop implanted systems more durable and less invasive. Despite dramatic progress in all directions, energy autonomy remains the Achilles heel of active implants. The most employed energy source remains today the single-use battery. For long-lasting implants such as pacemakers, the replacement of depleted batteries is necessary and requires a costly and invasive surgical procedure. To overcome these issues, different techniques have been investigated. The first approach consists in using the biomechanical energy available inside of the body, and the second is to transmit energy from outside of the human body. In the first case, it is possible, for example, to power the new generations of pacemakers using MEMS energy harvesting devices supplied by the heartbeat. In the second case, the wireless power transmission by induction between two coils (one in the implant, the other outside the body) is an increasingly widespread technology in the biomedical sector and in everyday life. The main difference between these two approaches is their power range: typically, a few microwatts for biomechanical energy harvesters, and milliwatts to watts for wireless power transmission. As part of this thesis, a new wireless power transmission technology has been developed. The considered system consists of two main blocks: the transmitter (out-body) and the receiver (located in the implant). The transmitter is a coil with no major constraints in terms of size and on-body position. The receiver is a magnetoelectric (ME) transducer. Investigating the use of a ME receiver, instead of the classical coil receiver, was in particular motivated by the willingness to reduce the alignment constraints of the classical coil-coil system, which is difficult to manage for implantable medical devices. The considered ME transducer is a composite made of piezoelectric and magnetostrictive layers. A magnetostrictive material has the property of mechanically deforming its structure, when exposed to a magnetic field. A piezoelectric material can be polarized and create an electric field under mechanical stress (direct effect). Therefore, the magnetic field, generated by the transmitter coil, induces an elastic deformation of the magnetostrictive material. This mechanical deformation is transmitted to the piezoelectric material, in which an electric field appears, generating an electric voltage across its electrodes. Thanks to the magnetic-mechanical-electrical energy conversion, achieved by the ME transducer, the medical implant can be wirelessly supplied or recharged. In this thesis, receivers with different sizes have been tested: 10 mm or 16 mm in diameter, and thickness comprised between 2 mm and 5 mm. Amongst numerous interesting experimental results, it was observed that thinner ME transducers with higher magnetostrictive volume ratio could generate higher electrical power than thicker samples with smaller magnetostrictive volume ratio. This result opens good prospects for the possibility of miniaturizing the ME transducer without losing efficiency in wireless power transfer. Concerning the in-vitro and phantom tests, the ME transducer exhibited very promising performances, converting enough power to recharge an implant up to 20 mm away from the transmitter coil, in the most unfavourable orientation. Such results are impossible to get using a coil-coil energy transmission system is the most unfavourable position (receiver perpendicular to the transmitter).In conclusion, the obtained results present very promising prospects for wireless energy transmission, in terms of miniaturised devices and adaptability to the localization of the implanted medical devices
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Chang, David Wei-Péng. "ST. JUDE MEDICAL: PULMONARY EDEMA MONITORING IN PACEMAKERS AND ICDS." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1112.
Full textAbstract:
Pulmonary edema occurs when fluid leaks from the pulmonary capillary network into the lung interstitium and alveoli. When the heart is not able to pump blood to the body efficiently, fluid can back up into the veins that take blood through the lungs to the left atrium. This then builds up the pressure in the blood vessels and fluid is pushed into the alveoli in the lungs. The fluid reduces normal oxygen movement through the lungs and can cause impaired gas exchange and respiratory failure. There are many causes of congestive heart failure that may lead to pulmonary edema such as heart attack, any diseases of the heart that weaken or stiffen the heart muscle, a leaking or narrowed heart valve, and sudden, severe high blood pressure.
Pulmonary edema is a strong indicator of congestive heart failure in patients and therefore can be used as a gauge for congestive heart failure. One way to diagnose cardiogenic pulmonary edema constantly is through the continuous monitoring of the transthoracic impedance throughout the day. One method to achieve this constant monitoring is through the use of a cardiac pacemaker or an implantable cardioverter defibrillator (ICD). Many patients who are at risk of heart failure have these medical devices implanted already. In these implantable cardiac devices, the connected cardiac leads can be utilized to continually screen several impedance vectors for decreases in impedance in the thoracic cavity. A pacemaker or ICD that implements Pulmonary Edema Monitoring is designed to continuously monitor these impedance vectors and alert the patient to seek medical attention. This thesis will discuss the implementation of Pulmonary Edema Monitoring via screening of multiple impedance vectors in a pacemaker or implantable cardioverter defibrillator and the effectiveness of this monitoring method. Furthermore, the design, implementation, and testing of this feature will be explored in greater detail.
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Gercek, Cihan. "Immunité des implants cardiaques actifs aux champs électriques de 50/60 Hz." Thesis, Université de Lorraine, 2016. http://www.theses.fr/2016LORR0226/document.
Full textAbstract:
La directive européenne 2013/35/UE précise les exigences minimales pour la protection des travailleurs exposés aux champs électromagnétiques et définit les porteurs d’implants comme travailleurs à risques particuliers. Concernant les porteurs de défibrillateur automatique implantable (DAI) ou de stimulateur cardiaque (SC), l’exposition au champ électrique ou magnétique d’extrêmement basse fréquence crée des inductions à l'intérieur du corps humain pouvant générer une tension perturbatrice susceptible de causer le dysfonctionnement de l’implant. Le sujet de ce travail de thèse porte sur la compatibilité électromagnétique des implants cardiaques soumis à un champ électrique basses fréquences (50/60 Hz). Des simulations numériques ont été effectuées afin de concevoir un banc expérimental pour l’exposition de fantômes incluant des stimulateurs ou des défibrillateurs implantables. Une étude expérimentale a permis d’établir par provocation les seuils de champ électrique permettant d’éviter tout dysfonctionnement éventuel de l’implant. Dans la partie simulation numérique ; un modèle humain virtuel (fantôme numérique contenant un implant cardiaque) a été placé en position debout sous une exposition verticale à un champ électrique. La méthode des éléments finis a été utilisée pour définir les phénomènes induits au niveau de l’implant cardiaque avec une résolution de 2mm (logiciel CST®). Dans la partie expérimentale, un banc d'essai dimensionné pour permettre de générer un champ électrique pouvant atteindre 100 kV/m aux fréquences 50-60 Hz a été conçu, optimisé et réalisé afin d’analyser le comportement des implants cardiaques. Plusieurs configurations ont été étudiées. Sur 54 implants cardiaques actifs testés (43 stimulateurs et 11 défibrillateurs) à des niveaux de champs électriques très élevés (100 kV/m) générés par notre dispositif expérimental, aux fréquences de 50-60 Hz, aucune défaillance n’a été observée pour des niveaux d’exposition publics et pour la plupart des configurations (+99%) sauf pour six stimulateurs cardiaques dans le cas d’une configuration « pire cas » peu réaliste en clinique : mode unipolaire avec une sensibilité maximale et en détection auriculaire. Les implants configurés avec une sensibilité nominale en mode bipolaire résistent bien à des champs électriques dépassant les valeurs seuils telles que définies par 2013/UE/35The European Directive 2013/ 35 / EU specify minimum requirements for the protection of workers exposed to electromagnetic fields and define with implants as “workers at particular risk”. Regarding the implantable cardioverter defibrillator wearers (ICD) or pacemaker (PM), exposure to electric or magnetic field of extremely low frequency creates inductions inside the human body that generate interference voltage which may cause the dysfunction of the implant. This thesis investigates the electromagnetic compatibility of cardiac implants subjected to an electric field low frequency (50/60 Hz). Computational simulations are effectuated in order to design an experimental bench for the exposure of a phantom including pacemakers or implantable defibrillators. A provocative study is established to define the electric field thresholds for preventing any malfunction of the implant. In numerical simulations; a virtual human model (digital phantom containing a cardiac implant) was placed in an upright position in a vertical exposure to an electric field. The finite element method was used to define the inductions in the cardiac implant level with a resolution of 2 mm (CST® software). In the experimental part, a test bench designed to allow generating an electric field up to 100 kV / m at frequencies 50-60 Hz was constructed, optimized and employed to investigate the behavior of cardiac implants.Several configurations were studied. 54 active cardiac implants (43 pacemakers and 11 defibrillators) are submitted to very high electric field of 50-60 Hz (up to 100 kV / m) inside the experimental bench. No failure was observed for public exposure levels for most configurations (+ 99%) except for six pacemakers in the case of a configuration clinically almost inexistent: unipolar mode with maximum sensitivity and atrial sensing.The implants configured with a nominal sensitivity in bipolar mode are resistant to electric fields exceeding the low action levels (ALs), even for the most high ALs, as defined by 2013 / 35 / EU
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Gercek, Cihan. "Immunité des implants cardiaques actifs aux champs électriques de 50/60 Hz." Electronic Thesis or Diss., Université de Lorraine, 2016. http://www.theses.fr/2016LORR0226.
Full textAbstract:
La directive européenne 2013/35/UE précise les exigences minimales pour la protection des travailleurs exposés aux champs électromagnétiques et définit les porteurs d’implants comme travailleurs à risques particuliers. Concernant les porteurs de défibrillateur automatique implantable (DAI) ou de stimulateur cardiaque (SC), l’exposition au champ électrique ou magnétique d’extrêmement basse fréquence crée des inductions à l'intérieur du corps humain pouvant générer une tension perturbatrice susceptible de causer le dysfonctionnement de l’implant. Le sujet de ce travail de thèse porte sur la compatibilité électromagnétique des implants cardiaques soumis à un champ électrique basses fréquences (50/60 Hz). Des simulations numériques ont été effectuées afin de concevoir un banc expérimental pour l’exposition de fantômes incluant des stimulateurs ou des défibrillateurs implantables. Une étude expérimentale a permis d’établir par provocation les seuils de champ électrique permettant d’éviter tout dysfonctionnement éventuel de l’implant. Dans la partie simulation numérique ; un modèle humain virtuel (fantôme numérique contenant un implant cardiaque) a été placé en position debout sous une exposition verticale à un champ électrique. La méthode des éléments finis a été utilisée pour définir les phénomènes induits au niveau de l’implant cardiaque avec une résolution de 2mm (logiciel CST®). Dans la partie expérimentale, un banc d'essai dimensionné pour permettre de générer un champ électrique pouvant atteindre 100 kV/m aux fréquences 50-60 Hz a été conçu, optimisé et réalisé afin d’analyser le comportement des implants cardiaques. Plusieurs configurations ont été étudiées. Sur 54 implants cardiaques actifs testés (43 stimulateurs et 11 défibrillateurs) à des niveaux de champs électriques très élevés (100 kV/m) générés par notre dispositif expérimental, aux fréquences de 50-60 Hz, aucune défaillance n’a été observée pour des niveaux d’exposition publics et pour la plupart des configurations (+99%) sauf pour six stimulateurs cardiaques dans le cas d’une configuration « pire cas » peu réaliste en clinique : mode unipolaire avec une sensibilité maximale et en détection auriculaire. Les implants configurés avec une sensibilité nominale en mode bipolaire résistent bien à des champs électriques dépassant les valeurs seuils telles que définies par 2013/UE/35The European Directive 2013/ 35 / EU specify minimum requirements for the protection of workers exposed to electromagnetic fields and define with implants as “workers at particular risk”. Regarding the implantable cardioverter defibrillator wearers (ICD) or pacemaker (PM), exposure to electric or magnetic field of extremely low frequency creates inductions inside the human body that generate interference voltage which may cause the dysfunction of the implant. This thesis investigates the electromagnetic compatibility of cardiac implants subjected to an electric field low frequency (50/60 Hz). Computational simulations are effectuated in order to design an experimental bench for the exposure of a phantom including pacemakers or implantable defibrillators. A provocative study is established to define the electric field thresholds for preventing any malfunction of the implant. In numerical simulations; a virtual human model (digital phantom containing a cardiac implant) was placed in an upright position in a vertical exposure to an electric field. The finite element method was used to define the inductions in the cardiac implant level with a resolution of 2 mm (CST® software). In the experimental part, a test bench designed to allow generating an electric field up to 100 kV / m at frequencies 50-60 Hz was constructed, optimized and employed to investigate the behavior of cardiac implants.Several configurations were studied. 54 active cardiac implants (43 pacemakers and 11 defibrillators) are submitted to very high electric field of 50-60 Hz (up to 100 kV / m) inside the experimental bench. No failure was observed for public exposure levels for most configurations (+ 99%) except for six pacemakers in the case of a configuration clinically almost inexistent: unipolar mode with maximum sensitivity and atrial sensing.The implants configured with a nominal sensitivity in bipolar mode are resistant to electric fields exceeding the low action levels (ALs), even for the most high ALs, as defined by 2013 / 35 / EU
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Chalon, Antoine. "Développement d’un dispositif médical implantable d’assistance ventriculaire par compression cardiaque directe : l’exosquelette cardiaque." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0313.
Full textAbstract:
L’assistance ventriculaire constitue une voie thérapeutique prometteuse de l’insuffisance cardiaque terminale. En dépit des progrès, notamment dans le développement des assistances de type shunt ventriculo-aortique, les écueils relatifs à l’encombrement, à l’alimentation et/ou aux interactions avec le sang de ces dispositifs limitent leur application clinique. Récemment, le concept de Compression Cardiaque Directe (DCC) apparaît comme une piste prometteuse en palliant les difficultés sus-citées. Dans ce travail de thèse, nous avons mis l’accent sur la conception et le test de faisabilité d’une solution de Compression Cardiaque Directe de type mécanique et entièrement implantable appelée l’Exosquelette Cardiaque. Notre travail expérimental a porté, dans un premier temps, sur la conception assistée par ordinateur et sur la modélisation numérique permettant ainsi d’optimiser et de prédire (i) les interactions tissus myocardiques/dispositifs et (ii) les pressions ventriculaires générées. Ensuite, un prototype fonctionnel a été réalisé par fabrication additive (titane, polymères) en s’appuyant sur les données issues de la modélisation et en respectant les contraintes énergétiques, mécaniques et architecturales anatomiques. Enfin, nous avons conduit une phase d’évaluation du potentiel de ce dispositif original sur un modèle de cœur ex vivo. Nous avons pu concevoir et valider un modèle numérique fondé sur le principe des éléments finis. Ce modèle à la fois simple et robuste, a permis de simuler (i) l’impact des points de fixation du dispositif sur le tissu cardiaque, (ii) l’efficacité de la compression externe sur la genèse des pressions intraventriculaires et (iii) l’influence de la compression mécanique externe sur le tissu cardiaque. Le prototype issu de ce travail de thèse a pu produire des résultats prometteurs concernant (i) la restauration physiologique de la pression intraventriculaire, (ii) la consommation énergétique suffisamment basse et (iii) le design compatible avec les contraintes anatomiques thoracique. L’ensemble de ces résultats esquissent la possibilité d’une implantation totale de l’Exosquelette Cardiaque chez le patientVentricular assistance is a promising therapeutic pathway for terminal chronic heart failure. Notwithstanding the progress made for the development of aorto-ventricular shunt pump among other things, the difficulties relatives to footprint, power supply and/or blood-device interactions are somehow limiting their clinical applications. Recently, direct cardiac compression (DCC) was suggested as a promising lead to overcome the difficulties mentioned above. In this work, we focused on the design and the feasibility of an implantable and mechanical Direct Cardiac Compression device called: The Cardiac Exosqueleton. Our experimental work used Computer Assisted Design (CAD) and numerical modeling to optimize and predict (i) tissue-device interactions and (ii) pressure generation inside ventricular cavities. Then, a functional prototype was realized by additive manufacturing (titanium, polymer) with the help of modeling data and with respect to the anatomical, mechanical and energetical limitations. Finally, we conducted an evaluation of the ability of our device on both in vitro setup and ex vivo heart. We were able to conceive and validate a numerical model based on finite element techniques. This simple yet robust model allowed us to study (i) the impact of suture fixation of a device at the apex of the heart, (ii) the influence of the direct cardiac compression on intracardiac pressures and (iii) overall and local tissue stress in the myocardium. Our prototype showed promising results concerning (i) the restoration of physiological intraventricular pressures, (ii) a low energy consumption and (iii) a shape that is compatible with the thoracic anatomical constraints. All of these results allow us to envision a total implantation of the cardiac exoskeleton into the patient
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Wagner, Quentin. "Optimisation de dispositifs médicaux thérapeutiques implantables pour l'ingénierie tissulaire osseuse et cartilagineuse." Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAJ114/document.
Full textAbstract:
Notre équipe a optimisé la formulation de dispositifs médicaux implantables pour l’ingénierie tissulaire osseuse et cartilagineuse. A ces fins, nous nous sommes basés sur des implants nanostructurés d’origine naturelle ou synthétique conçus au sein du laboratoire par la méthode d’électrospinning, pour imiter la matrice extracellulaire du compartiment osseux, et un hydrogel composé d’alginate et d’acide hyaluronique imitant la composition du compartiment cartilagineux. Dans une première partie de mon travail, pour la régénération osseuse, nous avons optimisé la formulation d’un implant nanostructuré à base de chitosane pour une accélération de cette régénération. Ceci a été possible en rendant actif ce dispositif médical implantable par incorporation de nanoparticules de silice, conférant à la construction nanocomposite des propriétés mécaniques accrues, et une excellente biocompatibilité avec le tissu hôte. Une autre étude pour la même visée a permis d’élaborer une nouvelle stratégie d’ensemencement de dispositif implantable synthétique et nanostructuré par des microtissus cellulaires, remplaçant un ensemencement de cellules isolées et permettant des performances de minéralisation accrues à l’intérieur de l’implant. Dans un deuxième temps, pour la régénération de l’unité ostéoarticulaire, nous avons proposé deux implants bi-compartimentés et hybrides comportant des microtissus de cellules souches mésenchymateuses. Ces implants sont composés d’un hydrogel contenant les cellules souches permettant la régénération du cartilage, et d’une membrane collagénique naturelle (Bio-Gide®) ou synthétique (membrane de polycaprolactone), dotée de nanoréservoirs (technologie brevetée par le laboratoire) de facteur de croissance ostéogénique (BMP-7) pour une régénération du socle osseux (os sous-chondral) de l’unité os-cartilage. La troisième partie de mon travail a concerné la vascularisation des implants osseux et particulièrement l’accélération du recrutement vasculaire. Dans ce cadre plus vasculaire, nous avons proposé une stratégie qui vise à doter un implant synthétique nanostructuré de facteur de croissance angiogénique (VEGF), puis à lui appliquer un ensemencement séquentiel de cellules mésenchymateuses adultes « ostéoblastes humains» et de cellules endothéliales humaines (HUVECs). Cette stratégie a permis un recrutement et une hiérarchisation accrue des cellules endothéliales dans l’implant. En conclusion, l’optimisation des implants développés au laboratoire permettra sans nul doute de proposer dans un futur proche de nouveaux dispositifs médicaux implantables (DMI) thérapeutique combinés de type DMI-MTI (Médicaments de Thérapie Innovante) pour l’ingénierie tissulaire osseuse et cartilagineuse en particulier en médecine régénérative ostéo-articulaireOur team optimized the formulation of implantable medical devices for bone and cartilage tissue engineering. To that end, we based our work on nanostructured implants, either natural or synthetic, made in the laboratory by electrospinning process, to mimic bone extracellular matrix, and hydrogel of alginate/hyaluronic acid to mimic cartilage extracellular matrix. First, concerning bone regeneration, we optimized the formulation of a nanostructured scaffold composed of natural chitosan to enhance bone regeneration. This was made possible by doping this implantable medical device with silica nanoparticles, offering this nanocomposite better mechanical properties, and excellent biocompatibility with host tissue. Another study with the same aim allowed elaborating a new cell seeding strategy, to seed these implantable medical devices with cell microtissues instead of single cells, offering higher mineralisation efficiencies within the implant. Consequently, for the regeneration of the osteochondral unit, we proposed two compartmented and hybrid implants comprising mesenchymal stem cells microtissues. Those implants are made of a hydrogel containing the stem cells, allowing the regeneration of cartilage, and a membrane, either natural (collagenic Bio-Gide®) or synthetic (electrospun polycaprolactone) equipped with nanoreservoirs (technology patented by the laboratory) of osteogenic growth factor (BMP-7) for the regeneration of osseous stand (the subchondral bone) of the bone-cartilage unit. Finally, to study the improvement in vascular recruitment, we proposed a new strategy combining the modification of an implantable device with angiogenic growth factor (VEGF), prior to its sequential seeding with mesenchymal cells “human osteoblasts” and human endothelial cells (HUVECs). This strategy allowed higher recruitment and structuration of endothelial cells within the implant. To conclude, the implant optimisation strategies developed in the laboratory will certainly allow proposing in the near future new combined Advanced Therapy Medicinal Products (ATMPs) and Implantable Medical Device for bone and cartilage regeneration, in particular in the field of osteoarticular regenerative nanomedicine
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Kelman, Christopher William, and christopher kelman@cmis csiro au. "Monitoring Health Care Using National Administrative Data Collections." The Australian National University. National Centre for Epidemiology and Population Health, 2001. http://thesis.anu.edu.au./public/adt-ANU20020620.151547.
Full textAbstract:
With the inevitable adoption of information technology into all areas of human pursuit, the potential benefits for health care should not be overlooked. In Australia, details of most health care encounters are currently recorded for administrative purposes. This results in an impressive electronic data-bank that could provide a national resource for health service evaluation.
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Evaluation of health services has become increasingly important to provide indicators of the benefits, risks and cost-effectiveness of treatments. However, if administrative data are to be used for this purpose, several questions must first be addressed: Are the current data collections accessible? What outcome measures can be derived from these data? Can privacy issues be managed? Could the quality of the data be improved? Is the existing infrastructure adequate to supply data for evaluation purposes? Could the existing system provide a basis for the development of an integrated health information system?
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The aims of the project were:
· To examine the potential for using administrative data to generate outcome measures and surveillance indicators.
· To investigate the logistics of gaining access to these data for the purpose of research. This to be achieved within the current ethical, political and financial framework.
· To compare the Australian health-service data system with the current international state-of-the-art.
· To develop suggestions for expansion of the present system as part of an integrated health record and information system. This system to manage patient records and provide data for quality management, treatment surveillance and cost-effectiveness evaluation as a routine activity.
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The thesis is presented in two parts. In the first part, a historical cohort study is described that involved patients with implantable medical devices. The potential to evaluate outcomes was investigated using all national health-service information currently available in electronic form. Record linkage techniques were used to combine and augment the existing data collections. Australias national health databases are to varying degrees, amenable to such linkage and cover doctor visits, pharmaceuticals, hospital admissions and deaths. The study focused on medical devices as an illustrative case but the results are applicable to the routine assessment of all medical and surgical interventions.
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For the Australian Medical Devices study, the records of 5,316 patients who had medical device implants in 1993-94 were selected from the archives of a major private health insurer. Five groups of medical implants were studied: heart valves, pacemakers, hips, vascular grafts and intra-optic lenses. Outcomes for these patients, including death, re-operation and health service utilisation, were compared and analysed.
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A comparison study was performed using data from the Manitoba Health database in Winnipeg, Canada. Manitoba provides a very similar demographic group to that found in Australia and is an example of a prototype integrated-health-information system. One of the principal advantages for research is that personally identified data about medical and hospital services are collected for all patients. Selection bias is eliminated because individual consent is not required for this type of research and all selected patients could be included in the study.
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The two studies revealed many barriers to the use of administrative data for health outcomes research. Service event data for the Australian cohort could be collected but only after long delays and hospital morbidity data were not available for the entire cohort. In contrast to the situation in Australia, the Manitoba data were both accessible and complete, but were lacking in detail in some areas.
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Analysis of the collected data demonstrated that without the addition of clinical data only general indications of trends could be deduced. However, with minimal supplementary clinical data, it was possible to examine differences in performance between brands of medical devices thus indicating one of the uses for this type of data collection.
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In the second part of the thesis, conclusions are presented about the potential uses and limitations of the existing system and its use as a basis for the development of a national Integrated Health Record and Information System (IHRIS). The need for the establishment of a systemic quality management system for health care is discussed.
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The study shows that linked administrative data can provide information about health outcomes which is not readily available from other sources. If expanded and integrated, the system that is currently used to collect and manage administrative data, could provide the basis for a national health information system. This system would provide many benefits for health care. Benefits would include the monitoring, surveillance and cost-effectiveness analysis of new and existing treatments involving medical devices, drugs and surgical procedures. An integrated health information system could thus provide for both clinical and administrative needs, while in addition providing data for research.
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Unfortunately, in Australia, the use of administrative data for this purpose is not currently feasible. The principal barrier is the existence of a culture within the Australian health care system which is not supportive of research and is deficient in quality and safety measures.
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Recent initiatives by both the Commonwealth and state governments have supported the introduction of measures to improve quality and safety in health care. It is argued here that an Integrated Health Record and Information System (IHRIS) would provide an essential component of any such scheme. The results of this study have important policy implications for health care management in both the administrative and clinical domains.
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Jordao, Zélzima Amélia. "Preuve de concept de l'utilisation d'un scaffold résorbable obtenu par impression 3D pour la reconstruction de l'hypoderme." Electronic Thesis or Diss., Université de Lille (2022-....), 2024. http://www.theses.fr/2024ULILS019.
Full textAbstract:
De nos jours, les patients qui ont la totalité de l'épaisseur de la peau détruite, dont l'hypoderme, disposent des solutions cliniques avec un certain nombre de limitations. Actuellement, le lipofilling est la principale solution pour la reconstruction de l'hypoderme grâce à la grande disponibilité du tissu adipeux autologue et au pouvoir de comblement de larges volumes. Cependant, le taux de résorption est de 80-90% dû à l'absence de vascularisation. L'ingénierie tissulaire peut être un outil efficace pour le développement d'une solution prometteuse pour améliorer l'efficacité du lipofilling. Cette thèse a pourobjectif de développer un scaffold poreux et résorbable par impression 3D pour soutenir la régénération vasculaire et du tissu adipeux. Les polymères synthétiques biorésorbables offrent de nombreux avantages tels que la facilité de mise en ouvre et leur adaptabilité (structure, propriétés, comportement, etc.) les rendant compatibles avec la réparation de l'hypoderme. De plus, leur association à l'impression 3D permet de créer des structures poreuses adaptées au tissu adipeux. Les travaux ont été menés sur 3 axes: le choix du matériau de conception, du design et la validation pré-clinique. Des études in vitro, avec le PLCL et le PDO, ont montré que le PLCL est plus adapté pour la conception du scaffold 3D. Le motif SCO a été choisi pour le design du scaffold 3D dont les propriétés mécaniques et la porosité sont compatibles avec les tissus mous. Ensuite, la validation pré-clinique du scaffold 3D en PLCL, sur le modèle murin, a prouvé qu'il peut être utilisé pour améliorer la survie et la vascularisation du tissu adipeuxNowadays, patients who have had the entire thickness of their skin destroyed, including the hypodermis, have access to clinical solutions with a number of limitations. At present, lipofilling is the main solution for hypodermis reconstruction, thanks to the wide availability of autologous adipose tissue and its ability to fill large volumes. However, the resorption rate is 80-90% due to the absence of vascularization. Tissue engineering can be an effective tool for developing a promising solution to improve the efficacy of lipofilling. The aim of this thesis is to develop a 3D-printed porous and resorbable scaffold to support vascular and adipose tissue regeneration. Synthetic bioresorbable polymers offer numerous advantages, such as ease of processing and adaptability (structure, properties, behavior, etc.), making them suitable for hypodermis repair. What's more, their combination with 3D printing makes it possible to create porous structures adapted to adipose tissue. Studies were carried out in 3 axes: choice of material, design and pre clinical validation. In vitro studies with PLCL and PDO showed that PLCL was more suitable for the development of the 3D scaffold. The SCO pattern was chosen for the design of the 3D scaffold, whose mechanical properties and porosity are compatible with soft tissue. Next, pre-clinical validation of the PLCL 3D scaffold, in the mouse model, proved that it can be used to improve survival and vascularization of adipose tissue
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Nesheim, Taylor Anthony. "THE BLE CLOAKER: SECURING IMPLANTABLE MEDICAL DEVICE COMMUNICATION OVER BLUETOOTH LOW ENERGY LINKS." DigitalCommons@CalPoly, 2015. https://digitalcommons.calpoly.edu/theses/1486.
Full textAbstract:
Historically Implantable Medical Devices (IMDs) such as pacemakers have only been able to communicate to external devices through close proximity means of communication, primarily through inductive telemetry. Because of the unlikelihood of an adversary being able to gain access to an IMD through this type of communication, these devices were never designed with security in mind. However the recent advent of IMDs that are equipped with long-range wireless capabilities has made it necessary to consider how to secure these devices from malicious attacks.
This work presents an implementation of prior work that developed a theoretical security model whose specific intent was to secure IMDs with long-range wireless capabilities against both passive and active adversaries, while also ensuring the safety of the patient. This implementation is known as the Bluetooth Low Energy (BLE) Cloaker model and provides a prototype system that uses BLE as the long-range communication medium between an emulated IMD, an external programmer, and the BLE Cloaker device itself. The BLE Cloaker acts as a secure data proxy between the IMD and the external programmer. This prototype shows the benefits and drawbacks of this theoretical model when used in a real world system as well as the security strengths and weaknesses of using BLE as the wireless link in a medical application.
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Duong, Jimmy Quoc Hy. "VERIFICATION PROCESS OF THE ST. JUDE MEDICAL ATRIAL FIBRILLATION IMPLANTABLE CARDIAC MONITOR DEVICE." DigitalCommons@CalPoly, 2010. https://digitalcommons.calpoly.edu/theses/414.
Full textAbstract:
The St. Jude Medical SJM ConfirmTM Implantable Cardiac Monitor (ICM) is a small implantable device that is used to detect arrhythmias and stores the electrogram (EGMs) records for physicians to verify the arrhythmia. The objective of this device is to provide physicians with the technology to monitor patients who are suspected of having arrhythmias but do not exhibit any symptoms of this heart condition. This device allows for long term continuous monitoring of patients and provides recordings for physicians to prove the existence of an arrhythmia. With the help of this device, doctors can make better decisions on determining what type of treatment patients would need and provide care for those who otherwise may be diagnosed too late.
The effort that goes into creating an ICM device is a strict and stringent process. The reason is to ensure that the device is of high quality. The software itself is quite complicated and the verification of the software is critical. Reviews of all verification test designs and test implementations are conducted to ensure complete coverage of software requirements. As part of the submission process for approval of these devices, a traceability report of the requirements to passed test cases must be provided, along with evidence that the software poses no harm to the patient.
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Trent, Alexis Raven. "Fabrication, Characterization and Cellular Interactions of Keratin Nanomaterial Coatings for Implantable Percutaneous Prosthetics." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/94417.
Full textAbstract:
Implantable medical devices face numerous complications when interfacing with soft tissue, and are plagued by negative responses from host tissue. One such class devices are percutaneous osseointegrated prosthetics (POP). POP consist of a bone anchored titanium post that extrudes through the skin and attaches to an external prosthetic. Compared to the traditional socket interface, POPs offer better stability, limb functionality, and osseoperception for both upper and lower prosthetic limbs. Although the POP surgery technique is well established, the main disadvantage to this technology remains the titanium (Ti) - skin interface. Some of the complications that can arise include epithelial downgrowth, mechanical tearing, and infection. Various types of coatings, surface structure, and antibiotic release technologies have been used to coat Ti in an effort to mitigate POP's associated obstacles, but these methods have failed to translate into published clinical studies and mainstream medical use.
One potential solution may be to mimic an interface already found in the human body, the fingernail-skin interface, which is infection-free and mechanically stable. The same keratins that make up the cortex of human hair fibers are found in the fingernail. These cortical human hair keratins can be extracted and purified, and fingernail-specific dimeric complexes coated onto Ti surfaces using silane coupling chemistry. Keratin has been used in other studies for its cell adhesion and differentiation properties, and it has been suggested that the Leu-Asp-Val (LDV) amino acid motif is the primary site responsible for cellular attachment.
In the present work, keratins extracted from human hair fibers and recombinant keratin nanomaterials (KN) were used to create biomimetic coatings on silanized Ti surfaces. These coatings were characterized and investigated for surface topography, elemental composition, cell adhesion motifs, and cell adhesion. Both keratin substrates showed the ability to create uniform coatings that retain a protein conformation that exhibits cell adhesion motifs. The coatings exhibit the ability to support cell adhesion of both epithelial and connective tissue cells. Application of fluid shear stress was used to test the mechanical adhesion strength of cells on keratin coatings. The structure, biochemical stability and sustained cellular adhesion of these coatings support keratin's capacity to provide a stable interface between POPs and skin. Side-by-side studies of extracted and recombinant keratins reveals that the recombinant form of these materials may provide distinct advantages for their use in POP devices.
Overall, this study confirmed that a uniform, silane-coupled keratin coating was feasible. We demonstrated the substrates contain a biological function in terms of cellular adhesion and phenotypic changes in skin-relevant cells. These results support the biomimetic function of keratin on silanized Ti, which may provide a suitable coating to translate percutaneous medical device coating applications toward clinical use.Ph. D.
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Fischer, Marie. "Élaboration in situ d’alliages de titane et de structures architecturées par fabrication additive : application aux dispositifs médicaux implantables." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0257/document.
Full textAbstract:
La problématique initiale part du constat que les échecs d’implants sont souvent causés par une inadéquation entre les propriétés élastiques de l’os et celles de l’implant. Aujourd’hui, ce problème de biocompatibilité mécanique suscite un intérêt croissant et a conduit au développement d’alliages de titane β-métastables qui possèdent un module d’élasticité faible, moitié moindre que celui de l’alliage Ti-6Al-4V classiquement utilisé dans les applications d’implantologie. De plus, les structures architecturées ou treillis font, elles aussi, l’objet d’intenses recherches dans le but de réduire le module d’élasticité et de maximiser la résistance. Leur mise en forme, avec une maîtrise précise de l’architecture, est possible grâce à la fabrication additive et les nombreuses possibilités qu’elle offre : liberté de design, gain matière, pièces complexes, customisation de masse... Ce travail de thèse porte sur la mise en œuvre de l’alliage de titane à bas module d’élasticité Ti-26Nb(%at.) par la technologie de fusion laser sur lit de poudres. Une stratégie d’élaboration in situ de ces alliages à partir de poudres élémentaires de Ti et de Nb est explorée, à la fois pour permettre d’éventuels ajustements de composition, et pour pallier au manque de disponibilité des alliages de titane sous forme de poudres. La démarche est réalisée avec deux morphologies de poudre, irrégulière et sphérique. Les effets des nombreux paramètres de ce procédé (puissance du laser, vitesse et stratégie de balayage...) sur l’homogénéité et la porosité des pièces élaborées sont quantifiés. Un alliage homogène peut être obtenu sous réserve de l’utilisation d’une densité d’énergie adaptée et d’une granulométrie de poudre tenant compte des températures de fusion respectives des éléments. La caractérisation de la microstructure met en évidence une texture marquée, dépendante de la stratégie de balayage. Les pièces élaborées présentent un bas module d’élasticité associé à une résistance mécanique élevée, avec une déformation élastique favorable par rapport à un alliage de référence coulé. Par ailleurs, un algorithme d’optimisation est développé et permet de contrôler les propriétés mécaniques d’une structure architecturée à partir de ses paramètres géométriques (rayon, longueur et orientation des poutres). La combinaison de cet alliage de titane à bas module d’élasticité et d’une structure architecturée développée à partir ce cet algorithme a été appliqué à une prothèse totale de hanche, qui a fait l’objet de simulations par éléments finis. L’évaluation du phénomène de stress-shielding montre que, comparativement à un modèle massif plus rigide, ce type de prothèse permet de réduire de façon significative la déviation des contraintes. En se rapprochant du modèle dit physiologique, cette prothèse peut être qualifiée de « biomimétique » sur le plan du comportement mécaniqueThe initial problematic arises from the fact that implant failure is often caused by a mismatch between the elastic properties of the bone and those of the implant. Nowadays, an increasing interest is given to this mechanical biocompatibility and led to the development of β-metastable titanium alloys that possess low Young’s modulus, about half that of the conventionally used Ti-6Al-4V alloy. Moreover, lattice structures are currently being the subject of many investigations with the aim of achieving low Young’s modulus and high strength. Their fabrication, with accurate control over the architecture, is made possible thanks to additive manufacturing processes and the several possibilities they offer: design freedom, reduced material usage rate, complex shapes, mass customisation... The present work focuses on the implementation of low modulus titanium alloy Ti-26Nb(at.%) by the means of selective laser melting. An in situ elaboration strategy, based on a mixture of elemental powders, is explored in order to allow potential composition adjustments and to overcome the unavailability of titanium alloy powders. The approach is carried out using two distinct powder morphologies, spherical and irregular. The effects of the numerous parameters of the process (laser power, speed, scanning strategy...) on homogeneity and porosity of the manufactured parts is quantified. A homogeneous alloy can be obtained subject to the use of suitable energy density levels and powder size distributions that take into account the respective fusion temperatures of both elements. Microstructure characterisation highlights a pronounced texture resulting from the scanning strategy. The elaborated samples display a low Young’s modulus associated with a high strength, and hence a favourable strength to elastic modulus ratio compared to the reference cast alloy. Furthermore, an optimization algorithm is developed and allows controlling the mechanical properties of a lattice structure with its geometrical parameters (radius, length and orientation of struts). The combined use of this low Young’s modulus titanium alloy with a lattice structure developed through this algorithm was applied to the design of a total hip prosthesis that was subjected to finite element simulations. Stress-shielding evaluation shows that, compared to a solid design, this kind of prosthesis permits to reduce stress-shielding significantly. By getting closer to a physiological model, this prosthesis can be qualified as “biomimetic” in terms of mechanical behaviour
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Canlas, Joel. "Creating software libraries to improve medical device testing of the Pacing System Analyzer (PSA) at St. Jude Medical." DigitalCommons@CalPoly, 2011. https://digitalcommons.calpoly.edu/theses/599.
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Software testing, specifically in the medical device field, has become increasingly complex over the last decade. Technological enhancements to simulate clinical scenarios and advancements in communicating to medical devices have created the need for better testing strategies and methodologies. Typical medical device companies have depended on manual testing processes to fulfill Food and Drug Administration (FDA) submission requirements specifically Class III devices which are life supporting, life sustaining devices. At St. Jude Medical, software testing of Class III devices such as implantable cardioverter-defibrillators (ICDs), pacemakers, and pacing analyzers are given top priority to ensure the highest quality in each product. High emphasis is made on improving software testing for ease of use and for catching more software errors in each device. A significant stride in testing has automated the process and has provided software verification teams with the tools they need to successfully test and deliver high quality products. By creating software libraries which interact with communication to the other interfaces needed to test medical devices, test engineers can focus on fully testing device requirements and will not be concerned with how each test will interact with the device or any other testing tools. The main focus will be a specific St. Jude Medical device known as the Pacing System Analyzer (PSA). The PSA device will be used to demonstrate how verification engineers are able to benefit from software libraries and allow the testing process and test development to be fully automated. New technologies and standards will be created to simulate clinical scenarios and to communicate to new devices. The goal is to use software engineering principles to create standard test libraries which sustain these changes while still allowing testers to focus on finding issues for each device.
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ASLIAN, HOSSEIN. "EFFECT OF MODERN RADIOTHERAPY ON PATIENTS WITH CARDIAC IMPLANTABLE ELECTRONIC DEVICES (CIEDs): A COMPREHENSIVE STUDY." Doctoral thesis, Università degli Studi di Trieste, 2020. http://hdl.handle.net/11368/2960311.
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During the last decades, cardiac implantable electronic device (CIED) therapy has become first line therapy for those who are at risk for life-threatening ventricular arrhythmias and those survived cardiac arrest. Therefore, there has be a continuous increase in the number of patients with CIEDs, especially in Europe and Italy.
Also, the number of new cancer patients is expected to experience an increase of 53% for 2030. Because radiotherapy (RT) is considered as one of the main component of cancer treatment, approximately 50% of cancer patients will receive at least one course of RT during their treatment. Accordingly, over the last decades, there has been an ever-increasing growth in the number of cancer patients and comorbid cardiovascular disease using CIEDs.
Since the publication of the American Association of Physicists in Medicine (AAPM)-TG34 report, as the earliest guideline published for the management of patients with CIEDs receiving general radiotherapy (RT) in 1994, technologies pertaining to all elements of the chain of RT have progressed. These developments, coupled with advancements in CIED technology, have led to a need for more research on this topic. Due to this fact, many studies have focused on the effect of radiotherapy on patients with CIEDs, and many aspects of this field have been investigated in the literature. However, with the widespread implementation of advanced RT technologies and techniques, the need to consider the different challenges of modern RT techniques when managing patients with CIEDs has arisen.
The main goal of this comprehensive study is to investigate effects of modern radiotherapy on CIED patients.
The thesis is divided in five chapters with an introductory chapter providing a very short explanation of CIED therapy and number of cancer patients with CIEDs.
In the first part of the study, chapter2, a deep review of the literature and analysis study have been conducted. This review and analysis highlighted the available sparse information in the literature and ended up by posing questions for future research.
In the second part of the research, chapter 3, the use of image-guided radiotherapy (IGRT) in patients with CIEDs was investigated. Accordingly, a multicenter dosimetry study to evaluate the imaging dose from Elekta XVI and Varian OBI kV-CBCT systems to cardiovascular implantable electronic devices (CIEDs) was carried out at four centers in the north of Italy, including university hospital of Trieste, Trento, Brescia, and Udine. The results of this study were applied to add new data in the literature and Associazione Italiana di Fisica Medica (aifm) working group.
In the third part, chapter 4, the effect of a stereotactic body radiotherapy (SBRT) using flattening filter-free beams on implantable cardioverter-defibrillators (ICDs), as widespread modern modality for the treatment of cancer, was done. First, a retrospective analysis of patients with CIEDs who underwent radiosurgery SBRT and radiosurgery (SRS) at Peter MacCallum Cancer Centre (the largest cancer research group in Australia) between 2014 and 2018 was performed. This was complemented through a phantom study through a multidisciplinary study between medical physicists, radiation oncologists and electrophysiologists at the university of Trieste, Peter Mac and Royal Melbourne Hospital. The results of this study were used to update some of the policies applied to manage CIED patients undergoing SBRT/SRS at PeterMac.
In the last part of this comprehensive study, chapter 5, a Monte Carlo (MC) study of out-of-field doses from an ELEKTA 6 and 15 MV photon beam in a homogeneous water phantom at depth of CIED and clinical depth was conducted. Correspondingly, a comparison between the MC results with MONACO treatment planning system (TPS), as a Monte Carlo-based TPS, and radiation dosimetry measurements was carried out to evaluate the accuracy of dose calculation outside the field, where a CIED is usually located.
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Noharet, Renaud. "Contribution à l'assurance qualité des dispositifs médicaux en implantologie orale : à propos de la précision du placement implantaire." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10109/document.
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L'assurance qualité est une discipline récente dans le domaine médical, d'autant plus en odontologie. Sa mise en oeuvre passe dans notre discipline essentiellement par l'application de règles d'exigences vis-à-vis des dispositifs médicaux utilisés au sein des cabinets dentaires. Les implants, les piliers, les prothèses implantaires mais également les guides chirurgicaux sont des exemples appliqués au domaine implantaire. Cette technique chirurgico-prothétique se doit d'être exécutée dans les meilleurs conditions avec une exigence optimale : chaque acte pouvant avoir des conséquences sur le patient et/ou l'avenir du traitement. Afin de répondre aux exigences d'assurance qualité du traitement implantaire, il semble que les guides chirurgicaux statiques puissent être un moyen afin d'améliorer le placement implantaire impactant donc la qualité de la thérapeutique mise en place. Dans un premier temps, les notions d'assurance qualité et des dispositifs médicaux sont remis en lumière, notamment au travers du filtre de l'implantologie orale. Ensuite, la qualité du traitement implantaire est discutée : des bases historiques jusqu'aux connaissances d'aujourd'hui. Il est important de maitriser l'évolution de cette technique et des outils associées afin de comprendre et donc d'utiliser les outils diagnostics et thérapeutiques à notre disposition aujourd'hui. Le dernier temps de ce travail constitue l'évaluation des outils actuels en implantologie (CFAO, stéréolithographie, chirurgie guide statique, informatique) au travers d'une étude sur sujets anatomiques. Cette étude évalue la précision du positionnement implantaire avec des guides dits conventionnels et des guides de chirurgie guidée statique. Cette précision est évaluée par comparaison des images préalables de planification et des examens tridimensionnels post-opératoiresThe quality assurance is a recent discipline in the medical domain, all the more in odontology. Its implementation passes in our discipline essentially by the application of rules of requirements towards medical devices used within dental surgeries. Implants, abutments, implant’s prosthesis but also the surgical guides are examples applied to the domain. This surgico-prosthetic technique owes be executed in the best conditions with an optimal requirement: every act which can have consequences on the patient and/or the future of the treatment. To meet the requirements of quality assurance of the treatment, it seems that the static surgical guides can be a way to improve the placement of implants thus impacting on the quality of the organized therapeutics. At first, the notions of quality assurance and medical devices are handed in light, in particular through the filter of the oral implantology. Then, the quality of the treatment is discussed: historic bases until the knowledge of today. It is important to master the evolution of this technique and tools associated to understand and thus use tools diagnoses and therapeutic at our disposal today. The last time of this work establishes) the evaluation of the current tools implantologie (CAD-CAM, stereolithography, surgery guides static, IT) through a study on anatomical subjects. This study estimates the precision of the implant’s positioning with conventional said guides and guides of static guided surgery. This precision is estimated by comparison of the preliminary images of planning and the post operative threedimensional examinations
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Bernard, Mélisande. "Etude de biocompatibilité des films à base de COC en tant que matériaux implantables." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLS378.
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L’objet de ce travail est l’étude de la biocompatibilité in vitro des matériaux à base de COC, afin d’évaluer leur potentiel de biomatériaux implantables.Cette évaluation est réalisée par le suivi de plusieurs paramètres : viabilité cellulaire/cytotoxicité, évaluation des phénomènes de stress oxydant, inflammatoires et hémocompatibilité. Une relation entre ces réponses biologiques et les propriétés physico chimiques des matériaux étudiés a été appréhendée.Les résultats montrent une bonne biocompatibilité des films testés avec un impact significatif de la présence des additifs (anti-oxydant et lubrifiant) sur les paramètres biologiques et physico-chimiques évalués.L’effet simulé du vieillissement biologique de ces matériaux sur leur biocompatibilité et leurs caractères physico-chimiques a également été étudié. Des conditions de pH et d’oxydation extrêmes, ainsi que le contact avec des macrophages pendant 1 mois, ont un effet sur la surface et sur l’interaction des films de COC avec l’environnement biologique sans compromettre leur biocompatbilité. La présence d’additifs a également eu un impact sur ces modifications.En suivant une logique de management du risque, la systématisation de l’ensemble des méthodes développées a permis d’obtenir une approche simplifiée et validée au sein du laboratoire, applicable à l’ensemble des matériaux naturels ou synthétiques susceptibles d’être utilisés dans la fabrication des DM implantablesAbstract : The purpose of this work is the study of the in vitro biocompatibility of COC-based materials in order to evaluate their potential as implantable biomaterials.This evaluation is carried out by monitoring several parameters: cell viability / cytotoxicity, evaluation of oxidative stress, inflammatory reactions and hemocompatibility. A relationship between these biological responses and physicochemical properties of the studied materials has been apprehended.Results show a good biocompatibility of the tested films with a significant impact of the presence of additives (anti-oxidant and lubricant) on the evaluated biological and physicochemical parameters.The simulated effect of biological aging of these materials on their biocompatibility and physico-chemical characteristics has also been studied. Extreme pH and oxidation conditions, as well as contact with macrophages during 1 month, affect the surface and interaction of COC films with the biological environment without compromising their biocompatibility. The presence of additives also had an impact on these changes.Following a risk management logic, the systematization of the developed methods within the laboratory made it possible to obtain a simplified and validated approach, applicable to all natural or synthetic materials that could be used for manufacturing implantable medical devices
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Siegel, Alice. "Etude de l’interaction mécanique entre un dispositif médical implantable actif crânien et le crâne face à des sollicitations dynamiques." Thesis, Paris, ENSAM, 2019. http://www.theses.fr/2019ENAM0012.
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Dans le cadre du développement accru d’implants crâniens actifs, l’étude de la résistance du complexe crâne-implant face à des chocs modérés est nécessaire afin d’assurer la sécurité du patient. Le but de cette thèse est de quantifier l’interaction mécanique entre le crâne et l’implant afin de développer un modèle éléments finis prédictif utilisable pour la conception des futurs dispositifs. Dans un premier temps, des essais matériaux sur titane et silicone ont permis d’extraire les paramètres élastiques, plastiques et de viscosité de leurs lois de comportement. Ces paramètres ont ensuite été implémentés dans un modèle éléments finis de l’implant sous sollicitations dynamiques, validé par des essais de choc de 2,5 J. L’implant dissipe une partie de l’énergie du choc et le modèle obtenu permet d’optimiser la conception de l’implant afin qu’il reste fonctionnel et étanche après l’impact. La troisième partie porte sur l’élaboration d’un modèle éléments finis du complexe crâne-implant sous sollicitations dynamiques. Des essais sur têtes cadavériques ovines ont permis d’optimiser les paramètres d’endommagement du crâne. Le modèle complet du complexe crâne-implant, corrélé à des essais de choc, apporte des éléments de réponses sur le comportement du crâne implanté face un choc mécanique, permettant ainsi d’optimiser la conception de l’implant afin de garantir l’intégrité du crâne.Ce modèle représente un premier outil pour l’analyse de l’interaction mécanique entre crâne et implant actif, et permet de dimensionner ce dernier de sorte à garantir son fonctionnement et son étanchéité, tout en assurant l’intégrité du crâneActive cranial implants are more and more developed to cure neurological diseases. In this context it is necessary to evaluate the mechanical resistance of the skull-implant complex under impact conditions as to ensure the patient’s security. The aim of this study is to quantify the mechanical interactions between the skull and the implant as to develop a finite element model for predictive purpose and for use in cranial implant design methodologies for future implants. First, material tests were necessary to identify the material law parameters of titanium and silicone. They were then used in a finite element model of the implant under dynamic loading, validated against 2.5 J-impact tests. The implant dissipates part of the impact energy and the model enables to optimize the design of implants for it to keep functional and hermetic after the impact. In the third part, a finite element model of the skull-implant complex is developed under dynamic loading. Impact tests on ovine cadaver heads are performed for model validation by enhancing the damage parameters of the three-layered skull and give insight into the behavior of the implanted skull under impact.This model is a primary tool for analyzing the mechanical interaction between the skull and an active implant and enables for an optimized design for functional and hermetic implants, while keeping the skull safe
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Lee, Hyung-Min. "A power-efficient wireless neural stimulating system with inductive power transmission." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53449.
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The objective of the proposed research is to advance the power efficiency of wireless neural stimulating systems in inductively powered implantable medical devices (IMD). Several innovative system- and circuit-level techniques are proposed towards the development of power-management circuits and wireless neural stimulating systems with inductive power transmission to improve the overall stimulation power efficiency.
Neural stimulating IMDs have been proven as effective therapies to alleviate neurological diseases, while requiring high power and performance for more efficacious treatments. Therefore, power-management circuits and neural stimulators in IMDs should have high power efficiencies to operate with smaller received power from a larger distance. Neural stimulating systems are also required to have high stimulation efficacy for activating the target tissue with a minimum amount of energy, while ensuring charge-balanced stimulation. These features provide several advantages such as a long battery life in an external power transmitter, extended-range inductive power transfer, efficacious and safe stimulation, and less tissue damage from overheating.
The proposed research presents several approaches to design and implement the power-efficient wireless neural stimulating IMDs: 1) optimized power-management circuits for inductively powered biomedical microsystems, 2) a power-efficient neural stimulating system with adaptive supply control, and 3) a wireless switched-capacitor stimulation (SCS) system, which is a combination structure of the power-management circuits and neural stimulator, to maximize both stimulator efficiency (before electrodes) and stimulus efficacy (after electrodes).
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Tortolano, Lionel. "Nécessite d'une approche analytique confondante dans l'évaluation des dispositifs médicaux implantables en biopolymères : application aux lentilles intraoculaires à base de polyacrylates." Thesis, Université Paris-Saclay (ComUE), 2016. http://www.theses.fr/2016SACLS121/document.
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L’implantation de lentilles intraoculaires est le traitement substitutif standard de la cataracte toutes origines confondues. L’implantation est faite à la suite de l’extraction du cristallin par phacoémulsification. Les implants souples, en acrylates hydrophobes, à bord carrés et « 1 pièce » sont recommandés pour prévenir la survenue de complications post-opératoires telles que l’opacification capsulaire postérieure. Cette complication multifactorielle est associée à un défaut de biocompatibilité. L’acte chirurgical, la physiopathologie du patient ainsi que la forme de la lentille intraoculaire modifient l’incidence. Malgré plusieurs mesures préventives, l’incidence n’est pas nulle et la prévalence continue d’augmenter avec le temps. Des cas tardifs d’opacifications surviennent jusqu’à 9 ans après la chirurgie. Un de nos objectifs dans le cadre de ce travail était de relier cette complication tardive au mécanisme de vieillissement des implants intraoculaires. Les résultats obtenus après hydrolyse et photo-oxydation, ont montré une altération des caractéristiques du polymère avec formation de composés néoformés de faibles masses moléculaires, qui diffusent au travers du polymère et migrent vers la surface en fonction de leur polarité et leur masse moléculaire. Il en résulte la création d’un gradient de concentrations de composés hydrophiles en surface et de composés hydrophobes dans les couches inférieures de l’implant. La vitesse du mécanisme de vieillissement est directement liée aux conditions (température, intensité de photo-oxydation). Par ailleurs, nous avons démontré l’existence d’une variation inter et intra lots des caractéristiques physico-chimiques de ces implants. Ces modifications de propriétés de surface constituent une explication à la survenue des complications tardives qui est liées à une modification de la biocompatibilité des implants intraoculaires, après vieillissementIntraocular lenses are the main treatment for cataract surgery whatever the origin. The implantation is done in the same surgical time as the lens extraction by phacoemulsification. Today, the recommended lenses are foldable acrylic copolymers with square edges and “1-piece”. This design decreases the incidence of adverse events as posterior capsular opacification (POC). This complication is multifactorial and is associated with a poor biocompatibility. The surgery and physiopathology are two others factor that impact the incidence of PCO. Despite many preventive actions, the incidence is not null and prevalence keep on increasing each year after the surgery. The late PCO cases occur until 9 years after the surgery. One of our objectives in the context of this work was to link this late complication to the aging mechanism of intraocular implants. The results obtained after hydrolysis and photo-oxidation have showed the characteristic modifications of the polymer with formation of low molecular weight compounds, which diffuse through the polymer and migrate to the surface, as a function of their polarity and their molecular weight. All these modifications have created concentration gradient. Indeed, the hydrophilic compounds have diffused on the surface and hydrophobic compounds in the implant matrix. The kinetic of the aging process is directly related to the aging conditions applied (temperature, intensity of photo-oxidation). Furthermore, we have demonstrated the existence of the variability between and within batches, of the physicochemical characteristics of these implants. These surface property modifications are an explanation for the occurrence of late complications that is related to a modification of the intraocular lenses biocompatibility after aging
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Cong, Peng. "WIRELESS BATTERYLESS IN VIVO BLOOD PRESSURE SENSING MICROSYSTEM FOR SMALL LABORATORY ANIMAL REAL-TIME MONITORING." Case Western Reserve University School of Graduate Studies / OhioLINK, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=case1228412139.
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Le, cann Sophie. "Etude biomécanique d'un nouvel implant rachidien pour préserver la croissance et la mobilité dans le traitement des scolioses." Thesis, Aix-Marseille, 2014. http://www.theses.fr/2014AIXM4074/document.
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Le "gold-standard" du traitement chirurgical des scolioses est l'arthrodèse, qui consiste, à l'aide d'une instrumentation adaptée, à corriger et redresser les déformations scoliotiques, puis fusionner les vertèbres du segment pathologique afin de consolider la correction réalisée. Cette fusion entraine la destruction de la biomécanique physiologique du rachis, en supprimant sa mobilité et sa croissance. Les travaux réalisés dans le cadre de cette thèse portent sur le développement et la validation d'un nouveau concept d'instrumentation rachidienne ayant pour objectifs de réduire voire d'arrêter l'évolution des déformations rachidiennes, en conservant croissance et mobilité. Ce nouveau dispositif a nécessité une étude biomécanique large, partant du concept nouveau de cet implant, passant par la mise au point d'une méthodologie expérimentale, la conception et la réalisation de prototypes, puis leur validation à travers des études numériques, mécaniques, tribologiques et in vivo sur gros animal. La caractérisation in vitro du dispositif porte sur des essais mécaniques de caractérisation de matériau et des essais tribologiques de caractérisation du frottement. La caractérisation in vivo consiste en deux études menées sur gros animal, le modèle de porc Landrace, une première sur l'étude de l'arrachement de vis pédiculaires, puis une seconde, de validation de concept, avec 2 mois d'implantation du montage. Les premières conclusions tirées de ces travaux sont positives quant au bon fonctionnement du système. Des études en cours et à venir permettront de compléter ces résultats, et de valider le système dans son ensemble, afin de permettre sa future mise sur le marchéThe "gold standard" of surgical treatment of scoliosis is arthrodesis, which, with an appropriate instrumentation, corrects and straightens the deformities and fuses the vertebra of the pathologic segment to consolidate the correction. This fusion leads to the destruction of the physiological biomechanics of the spine, destroying growth and mobility. The work done in this thesis focuses on the development and validation of a new concept of spinal instrumentation which objectives are to reduce or even stop the development of spinal deformities, maintaining growth and mobility. This device is composed of materials used in new ways, leading to friction issues that do not exist in the current spinal systems. Thus, the system required a large biomechanical study, starting from the new concept of this implant, carrying on the development of an experimental methodology, designing and prototyping and then validation through numerical, mechanical, tribological and large animal in vivo studies. In vitro characterization of the device involves characterization of material through mechanical tests, and characterization of the tribological behavior of the system. In vivo characterization consists of two studies on large animal, the Landrace pig model : a first one on pedicle screws pullout, and a second one with 2 months of implantation, to validate the concept. The initial findings from this work are positive about the correct behavior of this system. Ongoing and future studies will complement those results, and validate the system as a whole, to allow future marketing
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Inanlou, Farzad Michael-David. "Innovative transceiver approaches for low-power near-field and far-field applications." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/52245.
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Wireless operation, near-field or far-field, is a core functionality of any mobile or autonomous system. These systems are battery operated or most often utilize energy scavenging as a means of power generation. Limited access to power, expected long and uninterrupted operation, and constrained physical parameters (e.g. weight and size), which limit overall power harvesting capabilities, are factors that outline the importance for innovative low-power approaches and designs in advanced low-power wireless applications. Low-power approaches become especially important for the wireless transceiver, the block in charge of wireless/remote functionality of the system, as this block is usually the most power hungry component in an integrated system-on-chip (SoC). Three such advanced applications with stringent power requirements are examined including space-based exploratory remote sensing probes and their associated radiation effects, millimeter-wave phased-array radar for high-altitude tactical and geological imaging, and implantable biomedical devices (IMDs), leading to the proposal and implementation of low-power wireless solutions for these applications in SiGe BiCMOS and CMOS and platforms.
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Kulík, Jindřich. "Elektromagnetická interference kardiostimulátorů." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2008. http://www.nusl.cz/ntk/nusl-217723.
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This thesis deals with electromagnetic compatibility of implantable electro-medical devices using in cardiology. The main aim of this thesis is detection of the resistance of implantable pacemakers (PM) and implantable cardioverter defibrillators (ICD) to the electromagnetic interference. In the first part of this thesis, a function of the heart, which is necessary for understanding of PM and ICD operation, is described. The function and construction of PM and ICD is detailed in the theoretical part as well. The next part is focused on the electromagnetic compatibility. The next part is description of the measurement method and the experimental arrangement used for practical experiments with electromagnetic resistance of PM and ICD.
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Kabil, Julie. "Étude des interactions par radiofréquence entre multiples dispositifs médicaux pour la compatibilité IRM." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0001/document.
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Avec une population mondiale vieillissante, de plus en plus de personnes sont à risque de présenter des pathologies pour lesquelles l’Imagerie par Résonance Magnétique (IRM) est une modalité de choix : ainsi, le nombre d’examens IRM est en constante augmentation. Les patients âgés étant par ailleurs une population davantage susceptible de recevoir une implantation de dispositifs médicaux (tels qu’un pacemaker ou une prothèse de hanche), la sécurité des patients implantés en IRM est primordiale. En effet, cet appareil d’imagerie médicale fait intervenir différents champs électromagnétiques pouvant interagir avec un implant métallique et donner lieu à des risques potentiels pour le patient. Si des normes de compatibilité existent aujourd’hui pour soumettre individuellement les dispositifs médicaux à des tests standardisés et assurer leur innocuité en environnement IRM, les interactions entre multiples dispositifs médicaux vis-à-vis des ondes électromagnétiques radiofréquence (et des dangers qui peuvent en résulter) sont un domaine complexe qu’il est nécessaire de comprendre. L’objet de cette thèse est d’étudier ces interactions sur plusieurs niveaux : interactions intra-dispositif, interactions inter-dispositifs et interactions entre dispositif et plusieurs antennes. Une méthode de prédiction d’échauffement a été proposée pour simplifier l’étude de larges gammes d’implants, suivant les variations de paramètres caractérisant les différentes parties au sein d’une prothèse. Des simulations électromagnétiques et thermiques, associées à des mesures expérimentales dans un environnement IRM clinique, ont permis de mettre en évidence des phénomènes de couplages entre deux implants simplifiés et d’introduire une nouvelle métrique pour les quantifier. Enfin, une étude multi-antennes a fourni des éléments de réponse à la question de la sécurité d’un patient implanté en présence de plusieurs antennes, dans une configuration semblable à celle des examens en routine clinique. Les travaux présentés dans cette thèse ont ainsi permis d’évaluer les interactions vis-à-vis de la radiofréquence de l’IRM en présence d’un ou plusieurs dispositifs médicaux et antennes, ouvrant plusieurs perspectives pour aller vers une IRM sûre pour tousWith an aging population worldwide, more and more persons are at risk of suffering from pathologies which are best diagnosed or monitored with Magnetic Resonance Imaging (MRI): thus, the number of MRI exams is constantly increasing. Moreover, elderly patients being likely to undergo a medical device implantation (such as a pacemaker or a hip prosthesis) the safety of implanted patient in MRI is crucial. The medical imaging technique involves indeed different electromagnetic fields which can interact with a metallic implant and lead to potential hazard for the patient. Even though compatibility guidelines exist today to subject individually medical devices to standardized tests and ensure their harmlessness in an MRI environment, the interactions between multiple medical devices with respect to radiofrequency electromagnetic waves (and to the hazards that may follow) are a complex research area that has to be understood. The aim of this thesis is to study these interactions on different levels: intra-device interactions, inter-devices interactions and interactions between a device and several antennas. A prediction method has been proposed to simplify the study of large range of implants, according to the variations of parameters characterizing the different parts of a prosthesis. Electromagnetic and thermal simulations, associated with experimental measurements in a clinical MRI environment, allowed to highlight a coupling phenomenon between two simplified implants and to introduce a new metric to quantify them. Finally, a multi-antenna study led to some insights to answer the question of the safety of an implanted patient with several antennas, in a configuration similar to a clinical routine exam. Thus, the research work presented in this thesis allowed to assess the interactions with respect to MRI radiofrequency in presence of one or several medical devices and antennas, opening new prospects towards a safe MRI for everyone
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Kabil, Julie. "Étude des interactions par radiofréquence entre multiples dispositifs médicaux pour la compatibilité IRM." Electronic Thesis or Diss., Université de Lorraine, 2018. http://www.theses.fr/2018LORR0001.
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Avec une population mondiale vieillissante, de plus en plus de personnes sont à risque de présenter des pathologies pour lesquelles l’Imagerie par Résonance Magnétique (IRM) est une modalité de choix : ainsi, le nombre d’examens IRM est en constante augmentation. Les patients âgés étant par ailleurs une population davantage susceptible de recevoir une implantation de dispositifs médicaux (tels qu’un pacemaker ou une prothèse de hanche), la sécurité des patients implantés en IRM est primordiale. En effet, cet appareil d’imagerie médicale fait intervenir différents champs électromagnétiques pouvant interagir avec un implant métallique et donner lieu à des risques potentiels pour le patient. Si des normes de compatibilité existent aujourd’hui pour soumettre individuellement les dispositifs médicaux à des tests standardisés et assurer leur innocuité en environnement IRM, les interactions entre multiples dispositifs médicaux vis-à-vis des ondes électromagnétiques radiofréquence (et des dangers qui peuvent en résulter) sont un domaine complexe qu’il est nécessaire de comprendre. L’objet de cette thèse est d’étudier ces interactions sur plusieurs niveaux : interactions intra-dispositif, interactions inter-dispositifs et interactions entre dispositif et plusieurs antennes. Une méthode de prédiction d’échauffement a été proposée pour simplifier l’étude de larges gammes d’implants, suivant les variations de paramètres caractérisant les différentes parties au sein d’une prothèse. Des simulations électromagnétiques et thermiques, associées à des mesures expérimentales dans un environnement IRM clinique, ont permis de mettre en évidence des phénomènes de couplages entre deux implants simplifiés et d’introduire une nouvelle métrique pour les quantifier. Enfin, une étude multi-antennes a fourni des éléments de réponse à la question de la sécurité d’un patient implanté en présence de plusieurs antennes, dans une configuration semblable à celle des examens en routine clinique. Les travaux présentés dans cette thèse ont ainsi permis d’évaluer les interactions vis-à-vis de la radiofréquence de l’IRM en présence d’un ou plusieurs dispositifs médicaux et antennes, ouvrant plusieurs perspectives pour aller vers une IRM sûre pour tousWith an aging population worldwide, more and more persons are at risk of suffering from pathologies which are best diagnosed or monitored with Magnetic Resonance Imaging (MRI): thus, the number of MRI exams is constantly increasing. Moreover, elderly patients being likely to undergo a medical device implantation (such as a pacemaker or a hip prosthesis) the safety of implanted patient in MRI is crucial. The medical imaging technique involves indeed different electromagnetic fields which can interact with a metallic implant and lead to potential hazard for the patient. Even though compatibility guidelines exist today to subject individually medical devices to standardized tests and ensure their harmlessness in an MRI environment, the interactions between multiple medical devices with respect to radiofrequency electromagnetic waves (and to the hazards that may follow) are a complex research area that has to be understood. The aim of this thesis is to study these interactions on different levels: intra-device interactions, inter-devices interactions and interactions between a device and several antennas. A prediction method has been proposed to simplify the study of large range of implants, according to the variations of parameters characterizing the different parts of a prosthesis. Electromagnetic and thermal simulations, associated with experimental measurements in a clinical MRI environment, allowed to highlight a coupling phenomenon between two simplified implants and to introduce a new metric to quantify them. Finally, a multi-antenna study led to some insights to answer the question of the safety of an implanted patient with several antennas, in a configuration similar to a clinical routine exam. Thus, the research work presented in this thesis allowed to assess the interactions with respect to MRI radiofrequency in presence of one or several medical devices and antennas, opening new prospects towards a safe MRI for everyone
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Barbier, Thérèse. "Matériels et méthodes pour le développement de câbles compatibles IRM." Thesis, Université de Lorraine, 2017. http://www.theses.fr/2017LORR0313.
Full textAbstract:
L’Imagerie par Résonance Magnétique (IRM) est une technique d’imagerie de référence pour réaliser des diagnostics médicaux. Pour des patients implantés avec des dispositifs médicaux actifs, l’IRM peut engendrer des risques qui doivent être étudiés et minimisés. En effet, ces dispositifs sont constitués en partie de matériaux conducteurs et/ou magnétiques qui interagissent avec l’environnement électromagnétique d’une IRM. Lorsque ces dispositifs ont des câbles, une des interactions les plus problématiques est l’induction d’énergie dans ses câbles qui peut entrainer des stimulations, des dysfonctionnements ou des brûlures. Le premier objectif de cette thèse est de développer des outils pour étudier et quantifier ces interactions électromagnétiques d’une IRM sur un câble. Pour cela, des capteurs innovants compatibles IRM ont été développés pour mesurer la tension induite sur un câble, aux bornes de l’électronique d’entrée d’un dispositif médical actif. Des bancs de tests ont également été mis en place pour simuler les champs électromagnétiques d’une IRM. Le second objectif de cette thèse est de concevoir des câbles innovants qui réduisent au maximum ses interactions électromagnétiques avec une IRM. Nous avons réalisé un câble constitué d’un fil conducteur qui limite l’énergie induite par l’IRM grâce à son bobinage variable. Nous avons réalisé un deuxième câble avec un conducteur de fine épaisseur et des ruptures d’impédances sur sa longueurMagnetic Resonance Imaging (MRI) is an established imaging technique for medical diagnostics but could expose patients with active medical devices to risks that need to be studied and minimized. In fact, these devices encompass conductive and/or magnetic materials which interact with the electromagnetic field of the MRI. When these devices contain leads, MRI induced energy within the lead is considered to be one of the most problematic interaction as it can lead to stimulations, malfunction or burns. The first goal of this thesis is to create tools to study and quantify the electromagnetic interactions between an MRI and a lead. This has led to the design of novel MRI compatible sensors that measure induced voltage within leads connected active medical device entry terminals. Experimental MRI set-ups were also developed to simulate the MRI’s electromagnetic field. The second goal of this thesis is to design new leads that are minimally affected by the MRI’s electromagnetic field. Two proofs of concept were achieved. On the one hand, a lead capable of reducing MRI induced energy thanks to its winding was made. On the second hand, a second lead with a thin conductor and impedance mismatches along its length was created
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Héraud, Lorène. "Nouveaux alliages de titane superélastiques pour la fabrication de limes endodontiques : du matériau au prototype." Thesis, Rennes, INSA, 2016. http://www.theses.fr/2016ISAR0016.
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L’alliage NiTi (Nitinol) est à l’heure actuelle le seul alliage utilisé pour la fabrication de dispositifs médicaux qui nécessitent un effet mémoire de forme ou une superélasticité, comme les arcs orthodontiques, stents, cathéters et agrafes d’ostéosynthèse. La superélasticité est la capacité d’un alliage à se déformer de manière réversible bien plus qu’un alliage conventionnel. Elle est due à une transformation martensitique réversible entre deux phases cristallographiques, l’austénite et la martensite. Le NiTi entre dans la fabrication des limes endodontiques, un dispositif médical utilisé en dentisterie. Les limes endodontiques sont utilisées pour la mise en forme du système canalaire et la superélasticité de l’outil est nécessaire du fait que les canaux dentaires sont parfois très coudés. Cependant l’utilisation du NiTi souffre de quelques inconvénients, notamment de la toxicité reconnue du nickel mais aussi de sa rupture à caractère fragile et de sa difficulté de mise en forme.Certains alliages de titane du type β métastable présentent également des propriétés superélastiques. L’avantage est qu’ils peuvent être élaborés uniquement à partir d’éléments biocompatibles (i.e. Nb, Hf, Mo, Zr et Sn). Ils sont donc des candidats prometteurs pour le domaine médical.L’objectif de cette thèse est ainsi de déterminer l’intérêt potentiel des alliages de titane β métastable pour la réalisation de limes endodontiques.Dans ce travail de thèse, trois classes d’alliages ont été étudiées : le NiTi utilisé dans la fabrication des limes endodontiques actuelles, un alliage de titane β métastable disponible commercialement, le Beta III, de composition Ti-11,5Mo-6Zr-4,5Sn (% mass.) et des alliages de titane β métastable originaux élaborés en laboratoire, le Ti2448 et le Ti2334 de composition respectives Ti-24Nb-4Zr-8Sn (% mass.) et Ti-23Hf-3Mo-4Sn (% at.). Dans cette étude, l’influence de la composition et des traitements thermomécaniques sur les propriétés mécaniques et la transformation martensitique, responsable du comportement superélastique, a été étudiée. La transformation martensitique sous contrainte et son caractère réversible ont été plus profondément étudiés par une analyse in situ de diffraction des rayons X sous rayonnement synchrotron. Dans tous les dispositifs médicaux, il s’agit d’éviter la rupture intempestive pendant l’utilisation, aussi une résistance élevée à la rupture en chargement cyclique est nécessaire afin d’éviter les ruptures en fatigue dans le canal dentaire. Cette constatation a mené à étudier le comportement des alliages en fatigue et l’évolution de leur réponse mécanique et superélastique au cours des cycles. Enfin, le comportement des alliages une fois taillés en prototypes a été évalué avec l’équipement et les procédures de l’entrepriseThe NiTi (Nitinol) is the only alloy used for the manufacture of medical devices that require a shape memory effect or superelasticity, such as orthodontic arch wires, stents, catheters and osteosynthesis staples. The superelasticity is the ability of an alloy to deform reversibly much more than a conventional alloy. This is due to a reversible stress induced martensitic transformation between two crystallographic phases: austenite and martensite. NiTi is widely used in the manufacture of endodontic files, a medical device used in dentistry. The endodontic files are used to shape the root canal system and the superelasticity of the tool is necessary to follow very bent root canals. However, the use of NiTi suffers from several drawbacks, including the recognized toxicity of nickel but also its brittle character and its difficulty to manufacture. Some metastable β titanium alloys also exhibit superelastic properties. The advantage is that they can be elaborated with only biocompatible elements (i.e. Nb, Hf, Mo, Zr & Sn). Therefore, they are promising candidates for medical applications. The objective of this thesis is to determine the potential interest of metastable β titanium alloys for the production of endodontic files. Three classes of alloys were studied: the NiTi used in the manufacture of current endodontic files; a commercially available metastable β titanium alloy, the Beta III, whose composition is Ti-11,5Mo-6Zr-4,5Sn (weight %); and original metastable β titanium alloys developed in the laboratory, Ti2448 and Ti2334 having respective compositions of Ti-24Nb-4Zr-8Sn (weight %) and Ti-23Hf-3Mo-4Sn (atomic %). In this study, the influence of composition and thermomechanical treatments on the mechanical properties and on the stress induced martensitic transformation, responsible for the superelastic behavior, was studied. Stress induced martensitic transformation and its reversibility were most deeply studied by in situ X-ray diffraction analysis under synchrotron radiation. In all medical devices, it is needed to prevent accidental failure during use, therefore a high resistance to cyclic loading is necessary to avoid fatigue fractures in the canal system. This has led to study the fatigue behavior of alloys and the changes in their mechanical and superelastic responses during cycles. Finally, the behavior of alloys once manufactured into prototypes was evaluated with the company’s equipment and procedures
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Pugliano, Marion. "Conception et optimisation d'un implant thérapeutique combiné à des organoïdes de cellules souches pour la nanomédecine régénérative ostéoarticulaire." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAJ111.
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Notre équipe a mis au point une stratégie innovante d’implants thérapeutiques biphasiques, pour une régénération plus efficace et plus durable du cartilage articulaire, dans le cadre du traitement des lésions ostéochondrales. Ces implants pourraient représenter de meilleures alternatives aux traitements actuellement utilisés en chirurgie orthopédique. Dans un premier temps, nous avons élaboré un modèle d’implant thérapeutique à base de collagène de type II dérivé de méduse, fonctionnalisé par des nanoréservoirs de facteurs de croissance TGF-β3 et équipé de cellules souches mésenchymateuses humaines (hCSMs) dérivées de la moelle osseuse. La biocompatibilité et les propriétés chondrogéniques de cet implant ont été validées par des analyses in vitro, confirmant son potentiel thérapeutique pour la régénération du cartilage articulaire. Dans un second temps, nous nous sommes plus particulièrement concentrés sur la régénération de l’unité ostéochondrale. Il est en effet essentiel de régénérer un os sous-chondral sain, pour permettre une régénération stable du cartilage articulaire en surface. Dans ce but, nous avons développé un implant thérapeutique doté de deux compartiments : (i) un premier compartiment élaboré à partir d’un biomatériau synthétique de poly-ε-caprolactone (PCL), doté de nanoréservoirs de facteur de croissance BMP-7, pour la régénération de l’os sous-chondral : (ii) un second compartiment à base d’un hydrogel d’alginate et d’acide hyaluronique, ensemencé d’organoïdes hybrides de hCSMs et de chondrocytes humains, pour la régénération du cartilage articulaire. L’efficacité de cet implant biphasique a été confirmée in vitro et in vivo chez la souris. Dans un troisième temps, nous avons évalué notre stratégie d’implant thérapeutique biphasique en site intra-articulaire, chez l’animal de grande taille (brebis). Ces travaux ont permis de valider la faisabilité et l’efficacité de notre stratégie, combinant cette fois-ci : (i) un implant collagénique commercial, doté de nanoréservoirs de facteur de croissance BMP-2, pour la régénération de l’os sous-chondral ; (ii) un hydrogel d’alginate et d’acide hyaluronique, incorporant des organoïdes de CSMs de moelle osseuse de brebis, pour la régénération du cartilage articulaire. En conclusion, ces médicaments combinés de thérapie innovante, associant des biomatériaux naturels ou synthétiques (dispositif médical implantable), des molécules thérapeutiques et des cellules souches mésenchymateuses (médicament de thérapie innovante), permettent la régénération de l’unité ostéochondrale dans son ensemble. Cette stratégie novatrice permettra sans nul doute de grandes avancées en nanomédecine régénérative ostéoarticulaire, dans l’optique d’améliorer toujours plus le traitement et le confort des patientsOur team has developed an innovative strategy based on biphasic therapeutic implants allowing a more effective and long-lasting regeneration of articular cartilage in the treatment of osteochondral lesions. These implants may represent better alternatives to the current treatments used in orthopaedic surgery. First, we developed a jellyfish type II collagen therapeutic implant model, functionalized with TGF-β3 growth factor nanoreservoirs, and equipped with human bone marrow-derived mesenchymal stem cells (hMSCs). The biocompatibility and chondrogenic properties of this implant have been validated in vitro, confirming its therapeutic potential for the regeneration of articular cartilage. In a second time, we focused more on the regeneration of the osteochondral unit. Indeed, it is crucial to regenerate a healthy subchondral bone, to allow a stable regeneration of articular cartilage on the surface. To this end, we have developed a therapeutic implant with two compartments : (i) a first compartment based on a synthetic poly-ε-caprolactone (PCL) biomaterial, equipped with BMP-7 growth factor nanoreservoirs, for the regeneration of the subchondral bone ; (ii) a second compartment based on a hydrogel of alginate and hyaluronic acid, seeded with hybrid organoids of hMSCs and human chondrocytes, for the regeneration of the articular cartilage. The effectiveness of this biphasic implant has been confirmed in vitro and in vivo in mice. Thirdly, we evaluated our biphasic therapeutic implant strategy in the large animal (sheep). This work validated the feasibility and effectiveness of our strategy, by combining : (i) a commercial collagen implant with BMP-2 growth factor nanoreservoirs, for the regeneration of the subchondral bone ; (ii) a hydrogel of alginate and hyaluronic acid, incorporating organoids of sheep bone marrow MSCs, for the regeneration of articular cartilage. In conclusion, these combined advanced medicinal products (ATMPs), combining natural or synthetic biomaterials (implantable medical device), therapeutic molecules and mesenchymal stem cells, allow the regeneration of the entire osteochondral unit. This innovative strategy will undoubtedly lead to major advances in osteoarticular regenerative nanomedicine, aiming to improve the treatment and comfort of patients
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Monède, Hocquard Lucie. "Evaluation clinique, caractérisation mécanique et modélisation pour l'évolution de la conception d'un implant rachidien dynamique." Thesis, Bordeaux 1, 2012. http://www.theses.fr/2012BOR14721/document.
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L'objectif principal de tout dispositif médical implantable est d'améliorer l'état de santé du patient en lui assurant un risque minimum. Dans ce but, l'étude de l'implant rachidien B Dyn comporte plusieurs volets : - la réalisation d'un suivi clinique, - l’analyse et la proposition de solutions techniques (actions correctives), - la création d'un outil numérique pour des évolutions ultérieures (actions préventives).L’étude bibliographique initiale permet d'appréhender l'anatomie fonctionnelle du rachis lombaire, de comprendre les états pathologiques et leurs conséquences et enfin de faire un inventaire des techniques chirurgicales associées (résection osseuse, implantation de dispositifs...).Le suivi clinique d'une population de trente patients souligne ensuite les apports (somatiques et fonctionnels) du B Dyn dans sa conception première. Pour quelques cas, l'analyse des clichés radiographiques en position de flexion montre une détérioration naissante de l'anneau liée, probablement, à une surcharge accidentelle de l'implant. Ce constat impose une évolution de la conception de l'implant.Une analyse de la conception initiale et la caractérisation mécanique en traction, permettent de cibler les actions correctives à appliquer dans le cadre de cette évolution. La démarche mise en place s'appuie sur l'évaluation expérimentale pour sélectionner des solutions techniques satisfaisant aux critères fonctionnels ; elle conduit à une évolution du choix de matériau de l'anneau.Pour la réalisation d'évolutions ultérieures, un modèle éléments finis est créé. L’approche numérique se substitue ainsi à l’approche expérimentale contraignante et coûteuse. La caractérisation préalable des élastomères est nécessaire à l'obtention de données matériaux pour élaborer ce modèle. Les résultats des premières simulations d'un essai de traction sont comparés aux données expérimentales dans la perspective de la validation du modèle.A ce stade, l'étude du B Dyn propose une première solution d'évolution de l'implant et un outil numérique pour l'analyse future de solutions techniquesThe main focus of any implantable medical device is to improve the health of the patient by providing minimum risk. For this purpose, the study of the B Dyn spinal implant comprises several constituents: - The carrying out of a clinical follow up, - The analysis and choice of technical solutions (corrective actions) - The creation of a digital tool for further development (preventive actions).The initial bibliographical study enables to comprehend the functional anatomy of the lumbar spine, to understand the pathological states and their consequences and finally to list the associated surgical techniques (osseous resection, implantation of devices…).The clinical follow-up of a population of thirty patients then underlines the contributions (somatic and functional) of the B Dyn in its first design. For a few cases, the analysis of radiographs in flexion shows an incipient deterioration in the ring probably related to an accidental overloading of the implant. This observation requires an evolution in the design of the implant.An analysis of the initial design and the mechanical characterization in traction, allow targeting the corrective actions to be applied in the context of this evolution. The developed approach is based on the experimental evaluation in order to select technical solutions that would satisfy the functional criteria; this leads to an evolution of the choice of the ring material.To conduct subsequent developments, a finite element model is created. Thus the digital approach replaces the restrictive and expensive experimental approach. The preliminary characterization of elastomers is necessary to obtain materials data to work out this model. The results of the first simulations of a tensile test are compared to experimental data in the perspective of the model validation.At this stage, the B Dyn study provides a first solution of implant evolution and a numerical tool for the future analysis of technical solutions
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(5930498), Jiawei Zhou. "Ultrasonically Controlled/Powered Implantable Medical Devices." Thesis, 2019.
Find full textAbstract:
Implantable biomedical devices have been widely used to treat a variety of diseases for many decades. If allowed by the size and form factor, batteries have been the power source of choice in implantable devices (e.g., cardiac pacemakers). Batteries are, however, still big and come in shapes that are not ideal for minimally invasive deployment. Inductive powering is another commonly used energy source in which two well-aligned coils allow a transmitter to power the implanted receiver (e.g., cochlear implants). Once the receiver coil becomes small (mm-scale), the inductive powering link becomes very inefficient and sensitive to slight misalignment between the coils. Hence, it becomes increasingly difficult to power small devices implanted deep (>5 cm) within the tissue using inductive powering. Ultrasonic powering is an attractive alternative for powering miniature devices since it can penetrate deep into the tissue, it has greater efficiency at mm-scale receiver size, it can be omni-directional, and it is more amenable to miniaturization.
In this dissertation, I describe the use of ultrasonic waves to power and control mm-scale implantable devices. After a detailed look at ultrasonic transmission link, I will discuss factors affecting the power transfer efficiency. These include the effect of receiver aspect ratio and size on the resonant frequency and factors related to acoustic and electrical matching. A 3D printed acoustic matching layer in then described. I will discuss two applications using ultrasound to power and control implantable devices. The first is a low-power on-off acoustic control scheme to reduce the standby power consumption in implantable devices. The second is an ultrasonically powered electrolytic ablator with an on-board micro-light-source for the treatment of cancer.