Patients who have undergone treatment that has included the surgical implantation of a prosthetic device can become dissatisfied for many reasons. One cause for dissatisfaction is any adverse event where there is a demonstrable causal nexus with the failure of a device that is defective or at risk of being so. The magnitude of therapeutic product failure is considerable and therapeutic goods such as Vioxx, Thalidomide, silicon-gel-filled breast implants, contaminated blood products, cardiac pacemakers and valves, and orthopaedic devices are testimony to this. Many of these events have exposed a greyish area of Australian law that balances medical negligence with consumer protection and contract law. Australian product liability legislation that regulates the use of therapeutic goods is a complex amalgam of law that has at its foundations the Trade Practices Act 1974 (Cth) and the Therapeutic Goods Act 1989 (Cth). When a surgical device fails there can be exposure to liability. This thesis explores those important issues that can impact on individuals or on organisations and it is evident that where issues of product liability concern implanted surgical devices the current regulations for consumer protection may not always be the most appropriate. It is evident that there is a culture of under-reporting of adverse events to a Therapeutic Good Administration that does not have the resources to investigate the cause for failure of a surgical device. Furthermore, there is a potential for bias and conflict of interest in an environment where the regulator depends on the regulated for the funding of its existence. Other issues include the complex and often undesirable consequences of those partnerships that can evolve with the development of an implantable device and with the undertaking of clinical trials, the role of the learned intermediary, that interface between manufacturer and consumer, and the role of the expert witness, that interface between justice and injustice. These and other matters that can significantly influence any debate of implantable surgical device product liability are explored and recommendations are made that might form the basis of a Therapeutic Goods (Safe Medical Devices) Amendment Act.

Patients who have undergone treatment that has included the surgical implantation of a prosthetic device can become dissatisfied for many reasons. One cause for dissatisfaction is any adverse event where there is a demonstrable causal nexus with the failure of a device that is defective or at risk of being so. The magnitude of therapeutic product failure is considerable and therapeutic goods such as Vioxx, Thalidomide, silicon-gel-filled breast implants, contaminated blood products, cardiac pacemakers and valves, and orthopaedic devices are testimony to this. Many of these events have exposed a greyish area of Australian law that balances medical negligence with consumer protection and contract law. Australian product liability legislation that regulates the use of therapeutic goods is a complex amalgam of law that has at its foundations the Trade Practices Act 1974 (Cth) and the Therapeutic Goods Act 1989 (Cth). When a surgical device fails there can be exposure to liability. This thesis explores those important issues that can impact on individuals or on organisations and it is evident that where issues of product liability concern implanted surgical devices the current regulations for consumer protection may not always be the most appropriate. It is evident that there is a culture of under-reporting of adverse events to a Therapeutic Good Administration that does not have the resources to investigate the cause for failure of a surgical device. Furthermore, there is a potential for bias and conflict of interest in an environment where the regulator depends on the regulated for the funding of its existence. Other issues include the complex and often undesirable consequences of those partnerships that can evolve with the development of an implantable device and with the undertaking of clinical trials, the role of the learned intermediary, that interface between manufacturer and consumer, and the role of the expert witness, that interface between justice and injustice. These and other matters that can significantly influence any debate of implantable surgical device product liability are explored and recommendations are made that might form the basis of a Therapeutic Goods (Safe Medical Devices) Amendment Act.

Orientador: Eduardo Galera da Silva / Banca: Claudio Hideki Kubo / Banca: Rodrigo Máximo de Araújo / Resumo: Para que o tratamento endodôntico tenha sucesso, buscam-se meios de realizar uma limpeza eficiente e modelagem adequada do canal radicular. No entanto, na prática clínica, alguns problemas podem ser encontrados durante a instrumentação, sendo um deles a formação de micro trincas e linhas de fratura, que podem evoluir após o estresse causado pelas forças oclusais e resultar em uma fratura completa da raiz. O presente estudo teve por objetivo avaliar a incidência de micro trincas dentinárias em 48 incisivos inferiores humanos extraídos, utilizando estereomicroscópio e Tomografia Computadorizada de Feixe Cônico (TCFC), após o preparo do canal radicular com o sistema ProDesign S (Easy Equipamentos Odontológicos, Belo Horizonte, MG, Brasil) em movimento rotatório e reciprocante, o sistema ProDesign R (Easy Equipamentos Odontológicos, Belo Horizonte, MG, Brasil) em movimento reciprocante e o sistema Reciproc (VDW, Munich, Germany) em movimento reciprocante. Além disso, buscouse analisar a superfície dos instrumentos quando sem uso, após o primeiro uso, e sucessivamente até o terceiro uso, através de estereomicroscópio e microscopia eletrônica de varredura. Os resultados foram submetidos à análise estatística por meio da Prova de Friedman. Houve formação de micro trincas dentinárias em todos os grupos avaliados em Estereomicroscópio após o preparo do canal radicular utilizando o sistema ProDesign S em movimento rotatório e reciprocante, o sistema ProDesign R em movimento reciprocant... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: So that the endodontic treatment is successful, means to achieve an efficient cleaning and proper modeling of root canal are sought. However, in clinical practice, some problems may be encountered during the instrumentation, one of them being the formation of micro cracks and lines of fracture, which may evolve after the stress caused by occlusal forces and result in a complete root fracture. The objective of this study is to evaluate the incidence of dentin micro cracks in 48 extracted human incisors using stereomicroscope and cone beam computed tomography (TCFC), after the root canal preparation with ProDesign S system (Easy Equipamentos Odontológicos, Belo Horizonte, MG, Brazil), in rotatory and reciprocating movement, ProDesign R system (Easy Equipamentos Odontológicos, Belo Horizonte, MG, Brazil) in reciprocating movement and Reciproc system (VDW, Munich, Germany) in reciprocating movement. In addition, it was aimed to analyze the instruments surface when without use, after first use, and successively until the third use, through a stereomicroscope and scanning electron microscopy. The results will be subjected to statistical analysis by means of the Friedman test. Dentin micro cracks were formed in all groups evaluated in a stereomicroscope after root canal preparation using the ProDesign S system in rotating and reciprocating motion, the ProDesign R system in reciprocating motion and the Reciproc system in reciprocating motion; but without statistically significant dif... (Complete abstract click electronic access below) / Mestre

This work describes a self-sensing technique for a piezoelectrically driven MRI-compatible tweezer style end effector, suitable for robot assisted, MRI guided surgery. Nested strain amplification mechanisms are used to amplify the displacement of the piezo actuators to practical levels for robotics. By using a hysteretic piezoelectric model and a two port network model for the compliant nested strain amplifiers, it is shown that force and displacement at the tweezer tip can be estimated if the input voltage and charge are measured. One piezo unit is used simultaneously as a sensor and an actuator, preserving the full actuation capability of the device. Experimental validation shows an average of 12% error between the self-sensed and true values.

Os aços inoxidáveis martensíticos são amplamente utilizados em aplicações biomédicas devido a sua excelente resistência a corrosão e boas propriedades mecânicas. Entretanto, em aplicações como brocas para a implantodontia, seu desempenho é insatisfatório. Nesta aplicação usualmente utiliza-se de revestimentos como DLC para melhorar a resistência a corrosão, a resistência ao desgaste, bem como, diminuir o coeficiente de atrito broca-osso. Diversos trabalhos na literatura mostram que a nitretação a baixas temperaturas produz camadas superficiais de alta dureza e alta resistência à corrosão. Sabe-se também que o aumento da dureza do substrato melhora o suporte para a adesão do revestimento como o DLC. Estes tratamentos são conhecidos como duplex. Neste trabalho estudou-se o efeito da nitretação a baixa temperatura na resistência à corrosão e dureza de aços inoxidáveis martensiticos do tipo ASTM 420F, bem como, a influência na dureza e resistência à corrosão do tratamento duplex nitretação e DLC. Foram escolhidos cinco parâmetros de nitretação a baixa temperatura, em tempos diferentes para avaliar o comportamento na dureza e resistência à corrosão. O parâmetro que teve o melhor desempenho, atingindo maior dureza e proporcionando uma melhor resistência à corrosão entre os demais, foi a 380°C por 6 horas. Nessa condição, a dureza média de topo foi de 894 HV (1Kgf) e não apresentou corrosão na camada nitretada com revestimento DLC. Pode-se esperar que aplicado essas condições em uma broca cirúrgica, dentro de sua condição de procedimentos cirúrgicos, o desgaste da ferramenta seja menor, uma vez que a sua superfície tem maior dureza do que usualmente comercializada, e mantendo sua resistência à corrosão em ambientes agressivos em que são expostas. / Martensitics stainless steels are used in biomedical applications because of that yours excellent corrosion resistance and good mechanical properties. However, in applications such as drills for implant their performance has been unsatisfactory. This application is usually used how DLC coatings to improve corrosion resistance, wear resistance and to decrease the coefficient of drill bone friction. Several studies in the literature show that nitriding at low temperatures produce surface layers of high hardness and high resistance to corrosion. It is also known that increasing the hardness of the substrate it improves the adhesion of the coating as DLC. These treatments are known as duplex. In this work were studied the effect of low temperature nitriding on the corrosion resistance and hardness of martensitic stainless steel type ASTM 420F, as well as the influence on the hardness and corrosion resistance of nitriding and DLC duplex treatment. Five parameters of nitriding at low temperature, at different times to evaluate the behavior in the hardness and corrosion resistance were chosen. The parameter that had the best performance providing a higher hardness and better corrosion resistance was at 380°C for 6 hours. The average hardness of the drill top was 894 HV (1 Kgf) and not showed corrosion in duplex layer. It can be expected to apply these conditions in a surgical drill, in the tool wear will be less, since the surface has a higher hardness than usually marketed and the drill maintained the resistance to corrosion in aggressive environment that they are exposited.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Este trabalho propõe e implementa um software que realiza o cálculo de vários modelos de transformadores de instrumentação e orienta o usuário em como efetuar medições e correções importantes nos mesmos. O software engloba transformadores de baixa e média potência, até 500 W, e com frequências de até alguns megahertz. O software cobre 3 modelos: o clássico quadripolo de baixa potência e baixa frequência; o quadripolo T com capacitor de saída para baixa potência e média frequência; e o modelo delta-estrela completo, para transformadores eletrônicos de alta frequência. O trabalho teve como objetivo criar uma ferramenta para o projeto de transformadores, especialmente transformadores de saída de instrumentação biomédica, como por exemplo, o transformador de saída do bisturi eletrônico. O software indica o modelo de acordo com os dados de entrada ou por escolha do usuário. O software foi criado para uso gratuito e foi desenvolvido em código Java, de modo que qualquer pessoa interessada possa usá-lo. Por suas características, o software pode trabalhar em todos os computadores, desktops ou celulares, e em quase todos os sistemas operacionais, basta que o usuário tenha a máquina virtual Java instalada em seu hardware. O usuário deve inserir os coeficientes necessários para realizar os cálculos, obtendo os resultados numéricos e gráficos do módulo da impedância versus frequência e de fase versus frequência na tela ou em um arquivo de dados no formato CSV (comma-separated values). O módulo de saída gráfica apresenta o módulo e a fase da impedância de entrada (Zin) em função da frequência. Isto permite ao usuário ver as ressonâncias e comportamentos característicos do transformador e tomar providências para executar um projeto conforme suas necessidades. / This work describes a software that performs calculation and gives some tips about building and measuring transformers parameters up to 500 W till a few megahertz. The software emulates 3 models: the classical T model for low power and low frequency; the T model with output capacitance; and the complete delta-star model, for high frequency electronic transformers. This work aimed to create a tool for design of transformers, especially biomedical instrumentation output transformers, like the output electrosurgical device transformer. Tips like, for example, how to wrap the secondary coil to minimize intrinsic capacitance are presented to the software user. The software indicates the model according to input data or by user choice. The software is for free use and is programmed in Java language, so that, any person interested can use it. It will be available on the internet for free download. This software can work on all computers, desktops or mobiles, and on almost all operating systems, as long as the user has the virtual machine in his hardware. The user must insert the coefficients required to perform the calculations. After this insertion he must click on the calculation button, so the results and the impedance (modulus and phase) versus frequency graphs are seen on the screen. The user can additionally export an XY CSV (comma-separated values) data file. The software graphical output modulus and phase parts shows behavior of the input impedance (Zin) versus frequency. This makes possible for the user see the resonances and characteristic behavior of the transformer.

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Este trabalho propõe e implementa um software que realiza o cálculo de vários modelos de transformadores de instrumentação e orienta o usuário em como efetuar medições e correções importantes nos mesmos. O software engloba transformadores de baixa e média potência, até 500 W, e com frequências de até alguns megahertz. O software cobre 3 modelos: o clássico quadripolo de baixa potência e baixa frequência; o quadripolo T com capacitor de saída para baixa potência e média frequência; e o modelo delta-estrela completo, para transformadores eletrônicos de alta frequência. O trabalho teve como objetivo criar uma ferramenta para o projeto de transformadores, especialmente transformadores de saída de instrumentação biomédica, como por exemplo, o transformador de saída do bisturi eletrônico. O software indica o modelo de acordo com os dados de entrada ou por escolha do usuário. O software foi criado para uso gratuito e foi desenvolvido em código Java, de modo que qualquer pessoa interessada possa usá-lo. Por suas características, o software pode trabalhar em todos os computadores, desktops ou celulares, e em quase todos os sistemas operacionais, basta que o usuário tenha a máquina virtual Java instalada em seu hardware. O usuário deve inserir os coeficientes necessários para realizar os cálculos, obtendo os resultados numéricos e gráficos do módulo da impedância versus frequência e de fase versus frequência na tela ou em um arquivo de dados no formato CSV (comma-separated values). O módulo de saída gráfica apresenta o módulo e a fase da impedância de entrada (Zin) em função da frequência. Isto permite ao usuário ver as ressonâncias e comportamentos característicos do transformador e tomar providências para executar um projeto conforme suas necessidades. / This work describes a software that performs calculation and gives some tips about building and measuring transformers parameters up to 500 W till a few megahertz. The software emulates 3 models: the classical T model for low power and low frequency; the T model with output capacitance; and the complete delta-star model, for high frequency electronic transformers. This work aimed to create a tool for design of transformers, especially biomedical instrumentation output transformers, like the output electrosurgical device transformer. Tips like, for example, how to wrap the secondary coil to minimize intrinsic capacitance are presented to the software user. The software indicates the model according to input data or by user choice. The software is for free use and is programmed in Java language, so that, any person interested can use it. It will be available on the internet for free download. This software can work on all computers, desktops or mobiles, and on almost all operating systems, as long as the user has the virtual machine in his hardware. The user must insert the coefficients required to perform the calculations. After this insertion he must click on the calculation button, so the results and the impedance (modulus and phase) versus frequency graphs are seen on the screen. The user can additionally export an XY CSV (comma-separated values) data file. The software graphical output modulus and phase parts shows behavior of the input impedance (Zin) versus frequency. This makes possible for the user see the resonances and characteristic behavior of the transformer.

Accessing the inner ear presents a significant challenge for the diagnosis and treatment of inner ear diseases. Many existing techniques to access the inner ear are invasive and can cause permanent damage to the cochlea. Recently, a novel microneedle has been fabricated to perforate the round window membrane (RWM) – a membrane sealing one of the two openings in the cochlea. These perforations enhance drug delivery into the inner ear, potentially improving the efficacy of therapeutics. Furthermore, they allow for the aspiration of perilymph samples, which is essential for diagnosing inner ear diseases. However, owing to limited knowledge about the mechanical properties of the RWM, certain technical aspects remain unexplored. Specifically, the interaction between the RWM and the microneedle during perforation is yet to be examined. This investigation is pivotal for the optimal design of microneedles — those robust enough to perforate RWMs yet delicate enough to minimize damage. In this thesis, we conduct a thorough examination of the guinea pig RWM, encompassing its geometry and its mechanical responses to pressures from the middle ear and inner ear. Additionally, we also formulate a comprehensive constitutive law for the guinea pig RWM. Our exploration begins with the creation of a U-Net model tailored to automatically segment the RWM. Despite the presence of other structures in the same image—such as bone, the basilar membrane, and ambient noise—the model proved invaluable for efficiently and automatically segmenting the RWM. To enhance accuracy, post-processing techniques like connected component analysis and majority voting were incorporated. Using this 3D model, we proceeded to study the RWM’s geometry. Recognizing the shrinkage observed in fixed RWMs, we integrated fresh RWM data to estimate the shrinkage ratio. Subsequently, we analyzed both the overall RWM thickness and that of the middle connective tissue layer—crucial metrics for future RWM modeling. Next, we proposed a method to evaluate the in-plane deformation of the RWM due to applied pressure. This involved using a bulge test system to pressurize and deform the RWM, combined with confocal microscopy to track stained nuclei or pre-introduced fluorescent beads on the RWM. We then utilized the coherent point drift (CPD) algorithm to measure the displacement of beads and nuclei. Results indicated that both markers could be successfully used to measure the RWM’s displacement. Further analysis revealed the in-plane Lagrangian strain of the RWM, with a significant observation being that the direction of maximum in-plane Lagrangian strain is perpendicular to the fiber direction. This underscores the crucial role of collagen fibers in determining the RWM’s mechanical properties. To conclude our study, we devised a constitutive law for the RWM, conceptualizing it as a combination of the ground substance and a family of dispersed fibers. This model was integrated into a FEBioStudio plugin, facilitating simulations of the RWM’s mechanical reactions to different pressures. Although our simulations closely aligned with experimental findings, some discrepancies were noted, likely stemming from an incomplete understanding of fiber dispersions. Nevertheless, our constitutive law reinforces the notion that fibers primarily govern the RWM’s mechanical characteristics.

Thesis (PhD)--Macquarie University, Macquarie Graduate School of Management, 2001. / Bibliography: leaves 288-310. / Introduction -- Introduction to research problem and methodology -- Study context -- Theoretical framework - Review of the literature -- Study design and methods -- Study sites, surgical procedures, and labour input to surgical production -- New intra-operative artefacts: goals, choices and consequences -- Conclusion. / Surgical technologies since the late 1980s have undergone substantial innovations that have involved ...the adoption of new machines, instruments, and related surgical materials... referred to throughtout this thesis as intra-operative artefacts... typically represents a commitment of substantial financial resources by the hospitals concerned. However, little is documented about the process whereby the decisions are made to adopt new intra-operative artefacts, and no previous research appears to have explored the work-related consequences of new intra-operative artefact adoption within operating theatre services. This thesis explores the reasons why new intra-operative artefacts are adopted, how the decisions are made, who are the participants in the decsion process and what are the expected and actual organisational consequences of new intra-operative artefact adoption. / Electronic reproduction. / xii, 347 leaves, bound : / Mode of access: World Wide Web. / Also available in print form

A limpeza de instrumentos odontológicos, médicos e cirúrgicos (IOMC) em máquina lavadora ultrassônica (MLUS) utiliza energia mecânica (vibrações sonoras - cavitação), química (soluções detergentes) e térmica (temperatura) associadas ao tempo de exposição. A eficácia deste processo é certificada por meio de testes de controle recomendados por normas internacionais. Neste estudo buscou-se avaliar o desempenho da MLUS quanto aos parâmetros mínimos aceitáveis nas condições práticas de uso através de testes descritos em normas e discutir os fatores de interferência durante o processo que podem comprometer a eficiência da limpeza dos IOMC. Uma pesquisa inicial analisou as condições operacionais da MLUS por meio de questionário auto-aplicado nos estabelecimentos assistenciais à saúde (EAS) de Curitiba mostrando amplo uso da MLUS, com procedimentos técnicos de preparo do processo de limpeza, relação de tempo/temperatura e perfil dos ciclos com a carga de acordo com recomendações da literatura. Entretanto, não houve consenso sobre testes e normas técnicas a serem aplicadas. Assim, foram realizados testes de tiras e folhas de alumínio, indicadores químicos Sono Check® e TOSI® Lum Check para instrumentais canulados baseados em normas internacionais. Os resultados mostraram que todas as folhas de alumínio testadas apresentaram padrão uniforme de perfurações (100%), indicando a eficiência da cavitação. Nas tiras de folhas de alumínio houve perfurações semelhantes na maioria delas (89%) e uma apresentou poucas alterações (11%) apontando falhas no teste e/ou no funcionamento do equipamento. Em 3 testes de indicadores químicos Sono Check® foi obtido resultado positivo (37,5%), em outros três houve demora na alteração da cor mas acabaram positivos (37,5%) e dois indicadores de 2 testes não alteraram a cor (25%). Os resultados positivos (75%) comprovaram a eficácia da atividade ultrassônica e os negativos indicaram pontos cegos no processo de cavitação, o que pode ser atribuído a fatores interferentes na limpeza como: uso da mesma solução de limpeza em vários ciclos, tipo e disposição da carga, nível de preenchimento da solução no tanque, temperatura e divergência das ondas ultrassônicas entre instrumentais e paredes do equipamento. Os resultados dos testes TOSI® Lum Check foram negativos pois apresentaram resíduos de fibrina na superfície das placas de aço que pode estar relacionado a um reduzido tempo de exposição, temperatura não adequada, qualidade da água, diluição incorreta da solução de limpeza, teste mal posicionado, sobrecarga e/ou carga incorreta de IOMC e ineficiência da solução limpante. Concluiu-se que os testes de controle comprovam a eficácia da atividade ultrassônica na limpeza e detectam falhas no desempenho da MLUS atribuídas a fatores interferentes citados e para tanto é recomendado a elaboração de uma norma técnica no Brasil com a implementação da monitoração da atividade ultrassônica para a garantia da qualidade do processo de limpeza ultrassônica. / The cleaning of dental, medical and surgical instruments (DMSI) with ultrasonic cleaning equipment (UCE) makes use of mechanical (sound vibrations – cavitation), chemical (detergent solutions) and thermal (temperature) energies associated with exposure time. To check the performance of the cleaning process it is necessary the use of tests recommended by international standards. In this study we have evaluated the performance of UCE concerning its minimal acceptable parameters by means of tests described on standards as well as discussing the interfering factors which could compromise the cleaning process of DMSI. Initially, a survey analyzed the operating conditions of UEC through a questionnaire answered by professionals of several health care establishments (HCE) of Curitiba city. The results showed wide use of UCE in the investigated HCE, technical procedures for preparation of the cleaning process, time/temperature relationship and load cycle profiles according to literature recommendations. However there was no agreement on the type test selection or adoption of technical standards. Considering those results, practical tests were carried out for aluminium foils and strips, Sono Check® chemical indicators and TOSI® Lum Check for cannulated instruments, based on international standards. Aluminium foils (100%) and strips (89%) have showed uniformity in the produced holes, indicating efficiency of the cavitation. Some strips presented few modifications (11%), indicating failures in the test and/or functioning of the equipment. Chemical indicators Sono Check®| presented positive results (75%) proving the effectiveness of ultrasonic activity, however some (25%) presented negative results indicating blind spots due to difficulties in the cavitation process, which can be attributed to interfering factors such as: use the same cleaning solution in several cycles, type and disposition of the load, level of the solution in the tank, temperature and divergence of ultrasonic waves between instrument and walls of the equipment. TOSI® Lum Check for cannulated instruments showed negative results which can be attributed to reduced exposure time, not adequate temperature, water quality, incorrect dilution of the cleaning solution, test bad positioned, overload and/or incorrect load of the instruments, and inefficiency of the cleaning solution. It was concluded that the control tests can prove the effectiveness of the ultrasound in the cleaning activity and detect performance failures for UCE assigned to the cited interfering factors. Therefore, it is recommended the development of a technical standard in Brazil which should include types of tests, procedures and operational control of the cycle parameters in order to ensure the quality control of the ultrasonic cleaning process.