An Investigation on Biocompatibility of Bio-Absorbable Polymer Coated Magnesium Alloys

Advances in biomaterials have enabled medical practitioners to replace diseased body parts or to assist in the healing process. In situations where a permanent biomaterial implant is used for a temporary application, additional surgeries are required to remove these implants once the healing process is complete, which increases medical costs and patient morbidity. Bio-absorbable materials dissolve and are metabolized by the body after the healing process is complete thereby negating additional surgeries for removal of implants. Magnesium alloys as novel bio-absorbable biomaterials, have attracted great attention recently because of their good mechanical properties, biocompatibility and corrosion rate in physiological environments. However, usage of Mg as biodegradable implant has been limited by its poor corrosion resistance in the physiological solutions. An optimal biodegradable implant must initially have slow degradation to ensure total mechanical integrity then degrade over time as the tissue heals. The current research focuses on surface modification of Mg alloy (MZC) by surface treatment and polymer coating in an effort to enhance the corrosion rate and biocompatibility. It is envisaged that the results obtained from this investigation would provide the academic community with insights for the utilization of bio-absorbable implants particularly for patients suffering from atherosclerosis. The alloying elements used in this study are zinc and calcium both of which are essential minerals in the human metabolic and healing processes. A hydrophobic biodegradable co-polymer, polyglycolic-co-caprolactone (PGCL), was used to coat the surface treated MZC to retard the initial degradation rate. Two surface treatments were selected: (a) acid etching and (b) anodization to produce different surface morphologies, roughness, surface energy, chemistry and hydrophobicity that are pivotal for PGCL adhesion onto the MZC. Additionally, analyses of biodegradation, biocompatibility, and mechanical integrity were performed in order to investigate the optimum surface modification process, suitable for biomaterial implants. The study concluded that anodization created better adhesion between the MZC and PGCL coating. Furthermore, PGCL coated anodized MZC exhibited lower corrosion rate, good mechanical integrity, and better biocompatibility as compared with acid etched.

Adaptive Fault-Tolerant Teleoperation

While the robots gradually become a part of our daily lives, they already play vital roles in many critical operations. Some of these critical tasks include surgeries, battlefield operations, and tasks that take place in hazardous environments or distant locations such as space missions. In most of these tasks, remotely controlled robots are used instead of autonomous robots. This special area of robotics is called teleoperation. Teleoperation systems must be reliable when used in critical tasks; hence, all of the subsystems must be dependable even under a subsystem or communication line failure. These systems are categorized as unilateral or bilateral teleoperation. A special type of bilateral teleoperation is described as force-reflecting teleoperation, which is further investigated as limited- and unlimited-workspace teleoperation. Teleoperation systems configured in this study are tested both in numerical simulations and experiments. A new method, Virtual Rapid Robot Prototyping, is introduced to create system models rapidly and accurately. This method is then extended to configure experimental setups with actual master systems working with system models of the slave robots accompanied with virtual reality screens as well as the actual slaves. Fault-tolerant design and modeling of the master and slave systems are also addressed at different levels to prevent subsystem failure. Teleoperation controllers are designed to compensate for instabilities due to communication time delays. Modifications to the existing controllers are proposed to configure a controller that is reliable in communication line failures. Position/force controllers are also introduced for master and/or slave robots. Later, controller architecture changes are discussed in order to make these controllers dependable even in systems experiencing communication problems. The customary and proposed controllers for teleoperation systems are tested in numerical simulations on single- and multi-DOF teleoperation systems. Experimental studies are then conducted on seven different systems that included limited- and unlimited-workspace teleoperation to verify and improve simulation studies. Experiments of the proposed controllers were successful relative to the customary controllers. Overall, by employing the fault-tolerance features and the proposed controllers, a more reliable teleoperation system is possible to design and configure which allows these systems to be used in a wider range of critical missions.

A utilização da pesquisa operacional para o gerenciamento dos leitos em um hospital particular: estudo de caso baseado em simulação computacional

The hospital is a place of complex actions, where several activities for serving the population are performed such as: medical appointments, exams, surgeries, emergency care, admission in wards and ICUs. These activities are mixed with anxiety, impatience, despair and distress of patients and their families, issues involving emotional balance both for professionals who provide services for them as for people cared by them. The healthcare crisis in Brazil is getting worse every year and today, constitutes a major problem for private hospitals. The patient that comes to emergencies progressively increase, and in contrast, there is no supply of hospital beds in the same proportion, causing overcrowding, declines in the quality of care delivered to patients, drain of professionals of the health area and difficulty in management the beds. This work presents a study that seeks to create an alternative tool that can contribute to the management of a private hospital beds. It also seeks to identify potential issues or deficiencies and therefore make changes in flow for an increase in service capacity, thus reducing costs without compromising the quality of services provided. The tool used was the Computational Simulation –based in discrete event, which aims to identify the main parameters to be considered for a proper modeling of this system. This study took as reference the admission of a private hospital, based on the current scenario, where your apartments are in saturation level as its occupancy rate. The relocation of project beds aims to meet the growing demand for surgeries and hospital admissions observed by the current administration.

Utilização do titâneo na confecção de estruturas metálicas em prótese parcial removível

Due to properties such as excellent biocompatibility, high resistance to corrosion and low specific weight, titanium has been considered a material of great interest for Dentistry. It has been widely used in implants and orthognathic surgeries. Recently, titanium has been seen as a feasible alternative for the fabrication of removable partial denture frameworks, either in pure titanium (99.75%) or in titanium alloy forms (Ti-6Al-4V; Ti-6A1-7Nb). Based on a review of the literature, this work studied the use of titanium for the fabrication of removable partial denture frameworks, focusing on its advantages and disadvantages as well as its characteristics. It was concluded that the use of titanium is a convenient option for partially edentulous arches rehabilitation with quite satisfactory and promising clinical results. However, the need for highly-equipped laboratories increases the cost, preventing its large scale use.

Utilização do titâneo na confecção de estruturas metálicas em prótese parcial removível

Due to properties such as excellent biocompatibility, high resistance to corrosion and low specific weight, titanium has been considered a material of great interest for Dentistry. It has been widely used in implants and orthognathic surgeries. Recently, titanium has been seen as a feasible alternative for the fabrication of removable partial denture frameworks, either in pure titanium (99.75%) or in titanium alloy forms (Ti-6Al-4V; Ti-6A1-7Nb). Based on a review of the literature, this work studied the use of titanium for the fabrication of removable partial denture frameworks, focusing on its advantages and disadvantages as well as its characteristics. It was concluded that the use of titanium is a convenient option for partially edentulous arches rehabilitation with quite satisfactory and promising clinical results. However, the need for highly-equipped laboratories increases the cost, preventing its large scale use.

Efeito da geometria do implante dentário e do protocolo de fresagem óssea na estabilidade primária e na osseointegração inicial: estudo experimental em cães

CHAPTER 1 - This study histologically evaluated two implant designs: a classic thread design versus another specifically designed for healing chamber formation placed with two drilling protocols. Forty dental implants (4.1 mm diameter) with two different macrogeometries were inserted in the tibia of 10 Beagle dogs, and maximum insertion torque was recorded. Drilling techniques were: until 3.75 mm (regular-group); and until 4.0 mm diameter (overdrillinggroup) for both implant designs. At 2 and 4 weeks, samples were retrieved and processed for histomorphometric analysis. For torque and BIC (bone-to-implant contact) and BAFO (bone area fraction occupied), a general-linear model was employed including instrumentation technique and time in vivo as independent. The insertion torque recorded for each implant design and drilling group significantly decreased as a function of increasing drilling diameter for both implant designs (p<0.001). No significant differences were detected between implant designs for each drilling technique (p>0.18). A significant increase in BIC was observed from 2 to 4 weeks for both implants placed with the overdrilling technique (p<0.03) only, but not for those placed in the 3.75 mm drilling sites (p>0.32). Despite the differences between implant designs and drilling technique an intramembranous-like healing mode with newly formed woven bone prevailed. CHAPTER 2 - The objective of this preliminary histologic study was to determine whether the alteration of drilling protocols (oversized, intermediate, undersized drilling) present different biologic responses at early healing periods of 2 weeks in vivo in a beagle dog model. Ten beagle dogs were acquired and subjected to surgeries in the tibia 2 weeks before euthanasia. During surgery, 3 implants, 4 mm in diameter by 10 mm in length, were placed in bone sites drilled to 3.5 mm, 3.75 mm, and 4.0 mm in final diameter. The insertion and removal torque was recorded for all samples. Statistical significance was set to 95% level of confidence and the number of dogs was considered as the statistical unit for all comparisons. For the torque and BIC and BAFO, a general linear model was employed including instrumentation technique and time in vivo as independent. Overall, the insertion torque increased as a function of drilling diameter from 4.0 mm, to 3.75 mm, to 3.5 mm, with a significant difference in torque levels between all groups (p<0.001). Statistical assessment of BIC and BAFO showed significantly higher values for the 3.75 mm (recommended) drilling group was observed relative to the other two groups (p<0.001). Different drilling dimensions resulted in variations in insertion torque values (primary stability) and different pattern of healing and interfacial remodeling was observed for the different groups. CHAPTER 3 - The present study evaluated the effect of different drilling dimensions (undersized, regular, and oversized) in the insertion and removal torques of dental implants in a beagle dog model. Six beagle dogs were acquired and subjected to bilateral surgeries in the radii 1 and 3 weeks before euthanasia. During surgery, 3 implants, 4 mm in diameter by 10 mm in length, were placed in bone sites drilled to 3.2 mm, 3.5 mm, and 3.8 mm in final diameter. The insertion and removal torque was recorded for all samples. Statistical analysis was performed by paired t tests for repeated measures and by t tests assuming unequal variances (all at the 95% level of significance). Overall, the insertion torque and removal torque levels obtained were inversely proportional to the drilling dimension, with a significant difference detected between the 3.2 mm and 3.5 mm relative to the 3.8 mm groups (P < 0.03). Although insertion torque–removal torque paired observations was statis- tically maintained for the 3.5 mm and 3.8 mm groups, a significant decrease in removal torque values relative to insertion torque levels was observed for the 3.2 mm group. A different pattern of healing and interfacial remodeling was observed for the different groups. Different drilling dimensions resulted in variations in insertion torque values (primary stability) and stability maintenance over the first weeks of bone healing.

Live volumetric (4D) visualization and guidance of in vivo human ophthalmic surgery with intraoperative optical coherence tomography.

Minimally-invasive microsurgery has resulted in improved outcomes for patients. However, operating through a microscope limits depth perception and fixes the visual perspective, which result in a steep learning curve to achieve microsurgical proficiency. We introduce a surgical imaging system employing four-dimensional (live volumetric imaging through time) microscope-integrated optical coherence tomography (4D MIOCT) capable of imaging at up to 10 volumes per second to visualize human microsurgery. A custom stereoscopic heads-up display provides real-time interactive volumetric feedback to the surgeon. We report that 4D MIOCT enhanced suturing accuracy and control of instrument positioning in mock surgical trials involving 17 ophthalmic surgeons. Additionally, 4D MIOCT imaging was performed in 48 human eye surgeries and was demonstrated to successfully visualize the pathology of interest in concordance with preoperative diagnosis in 93% of retinal surgeries and the surgical site of interest in 100% of anterior segment surgeries. In vivo 4D MIOCT imaging revealed sub-surface pathologic structures and instrument-induced lesions that were invisible through the operating microscope during standard surgical maneuvers. In select cases, 4D MIOCT guidance was necessary to resolve such lesions and prevent post-operative complications. Our novel surgical visualization platform achieves surgeon-interactive 4D visualization of live surgery which could expand the surgeon's capabilities.

The impact of user charges on patient choice of healthcare services in Ireland

This research assesses the impact of user charges in the context of consumer choice to ascertain how user charges in healthcare impact on patient behaviour in Ireland. Quantitative data is collected from a subset of the population in walk-in Urgent Care Clinics and General Practitioner surgeries to assess their responses to user charges and whether user charges are a viable source of part-funding healthcare in Ireland. Examining the economic theories of Becker (1965) and Grossman (1972), the research has assessed the impact of user charges on patient choice in terms of affordability and accessibility in healthcare. The research examined a number of private, public and part-publicly funded healthcare services in Ireland for which varying levels of user charges exist depending on patients’ healthcare cover. Firstly, the study identifies the factors affecting patient choice of privately funded walk-in Urgent Care Clinics in Ireland given user charges. Secondly, the study assesses patient response to user charges for a mainly public or part-publicly provided service; prescription drugs. Finally, the study examines patients’ attitudes towards the potential application of user charges for both public and private healthcare services when patient choice is part of a time-money trade-off, convenience choice or preference choice. These services are valued in the context of user charges becoming more prevalent in healthcare systems over time. The results indicate that the impact of user charges on healthcare services vary according to socio-economic status. The study shows that user charges can disproportionately affect lower income groups and consequently lead to affordability and accessibility issues. However, when valuing the potential application of user charges for three healthcare services (MRI scans, blood tests and a branded over a generic prescription drug), this research indicates that lower income individuals are willing to pay for healthcare services, albeit at a lower user charge than higher income earners. Consequently, this study suggests that user charges may be a feasible source of part-financing Irish healthcare, once the user charge is determined from the patients’ perspective, taking into account their ability to pay.

SCAPHOID AND LUNATE CARPAL MECHANICS OVER THE SPECTRUM OF HEALTHY FUNCTION

When ligaments within the wrist are damaged, the resulting loss in range of motion and grip strength can lead to reduced earning potential and restricted ability to perform important activities of daily living. Left untreated, ligament injuries ultimately lead to arthritis and chronic pain. Surgical repair can mitigate these issues but current procedures are often non-anatomic and unable to completely restore the wrist’s complex network of ligaments. An inability to quantitatively assess wrist function clinically, both before and after surgery, limits the ability to assess the response to clinical intervention. Previous work has shown that bones within the wrist move in a similar pattern across people, but these patterns remain challenging to predict and model. In an effort to quantify and further develop the understanding of normal carpal mechanics, we performed two studies using 3D in vivo carpal bone motion analysis techniques. For the first study, we measured wrist laxity and performed CT scans of the wrist to evaluate 3D carpal bone positions. We found that through mid-range radial-ulnar deviation range of motion the scaphoid and lunate primarily flexed and extended; however, there was a significant relationship between wrist laxity and row-column behaviour. We also found that there was a significant relationship between scaphoid flexion and active radial deviation range of motion. For the second study, an analysis was performed on a publicly available database. We evaluated scapholunate relative motion over a full range of wrist positions, and found that there was a significant amount of variation in the location and orientation of the rotation axis between the two bones. Together the findings from the two studies illustrate the complexity and subject specificity of normal carpal mechanics, and should provide insights that can guide the development of anatomical wrist ligament repair surgeries that restore normal function.

Reassembled, Slightly Askew:Composition & Sound Design

Reassembled, Slightly Askew is an autobiographical, immersive audio-based artwork based on Shannon Sickels’ experience of falling critically ill with a rare brain infection and her journey of rehabilitation with an acquired brain injury. Audience members experience Reassembled individually, listening to the audio via headphones while lying on a bed. The piece makes use of binaural microphone technology and spatial sound design techniques, causing listeners to feel they are inside Shannon’s head, viscerally experiencing her descent into coma, brain surgeries, early days in the hospital, and re-integration into the world with a hidden disability. It is a new kind of storytelling, never done before about this topic, that places the listener safely in the first-person perspective with the aim of increasing empathy and understanding. Reassembled… was made through a 5-year collaboration with an interdisciplinary team of artists led by Shannon Sickels (writer & performer), Paul Stapleton (composer & sound designer), Anna Newell (director), Hanna Slattne (dramaturgy), Stevie Prickett (choreography), and Shannon’s consultant neurosurgeon and head injury nurse. It’s development and production has been made possible with the support of a Wellcome Trust Arts Award, the Arts Council NI, Sonic Arts Research Centre, Belfast's Metropolitan Arts Centre, and grants from the Arts & Disability Award Ireland scheme. In its 2015 premiere year, Reassembled had 99 shows across Northern Ireland, including at the Cathedral Quarter Arts Festival (the MAC, Belfast) and BOUNCE Arts & Disability Forum Festival (Lyric Theatre, Belfast). It was awarded 5 stars in the Stage, a Hospital Club h100 Theatre & Performance Award, and been shared at medical conferences and trainings across the UK. It continues to be presented in diverse artistic and educational contexts, including as part of A Nation’s Theatre Festival in 2016 at Battersea Arts Centre in London where it was given 4 star reviews in the Guardian, Time Out London and the Evening Standard. "A real-life ordeal, captured by a daring, disorientating artistic collaboration, which works brilliantly on so many levels…It should be available on prescription.” — The Stage ★★★★★ www.reassembled.co.uk Audio clips and documentary footage available here: http://www.paulstapleton.net/portfolio/reassembled-slightly-askew

Bowel-associated dermatosis-arthritis syndrome in an adolescent with short bowel syndrome

Bowel-associated dermatosis-arthritis syndrome (BADAS) is a neutrophilic dermatosis, characterized by the occurrence of arthritis and skin lesions related to bowel disease with or without bowel bypass. We report an unusual case of BADAS in a 15-year-old white male with congenital aganglionosis of the colon and hypoganglionosis of the small intestine and multiple bowel surgeries in childhood complicated by short bowel syndrome. He presented with recurrent peripheral polyarthritis, tenosynovitis, and painful erythematous subcutaneous nodules located on the dorsolateral regions of the legs and on the dorsa of the feet. Histological examination disclosed a neutrophilic dermatosis confirming the diagnosis of BADAS.Although an uncommon disease, especially at pediatric age, it is important to evoke the diagnosis of BADAS in children and adolescents with bowel disease, because treatment options and prognosis are distinct from other rheumatologic conditions.

Dacriocistorrinostomia endoscópica nasal: resultados do Hospital Professor Doutor Fernando Fonseca

Objectivo: analisar os resultados da experiência de um hospital distrital na realização de dacriocistorrinostomias (DCR) endoscópicas e determinar o papel actual desta técnica para tratamento de obstruções da via nasolacrimal. Materiais e Métodos: Reviram-se os processos clínicos de 67 dacriocistorrinostomias endoscópicas consecutivas realizadas no Hospital Fernando Fonseca entre Janeiro de 1997 e Dezembro de 2012. Analisou-se a clínica apresentada pelos doentes, o nível da estenose detectado na dacriocistografia, as complicações intra e pós-operatórias e os resultados funcionais e anatómicos pós-operatórios. Resultados: Dos 51 doentes, 12 eram do sexo masculino e 34 do sexo feminino, com média de idades de 57 anos. A epífora foi a queixa predominante. Com a excepção de dois casos, todas as cirurgias foram executadas com instrumentos de dissecção motorizados. O sucesso da DCR endoscópica foi de 78,1%. Conclusões: A DCR endoscópica é uma técnica simples, segura e eficaz para o tratamento das obstruções distais da via nasolacrimal.

Bowel-associated dermatosis-arthritis syndrome in an adolescent with short bowel syndrome

Bowel-associated dermatosis-arthritis syndrome (BADAS) is a neutrophilic dermatosis, characterized by the occurrence of arthritis and skin lesions related to bowel disease with or without bowel bypass. We report an unusual case of BADAS in a 15-year-old white male with congenital aganglionosis of the colon and hypoganglionosis of the small intestine and multiple bowel surgeries in childhood complicated by short bowel syndrome. He presented with recurrent peripheral polyarthritis, tenosynovitis, and painful erythematous subcutaneous nodules located on the dorsolateral regions of the legs and on the dorsa of the feet. Histological examination disclosed a neutrophilic dermatosis confirming the diagnosis of BADAS.Although an uncommon disease, especially at pediatric age, it is important to evoke the diagnosis of BADAS in children and adolescents with bowel disease, because treatment options and prognosis are distinct from other rheumatologic conditions.

Resultados de cirurgia estapédica: a experiência recente do Hospital Professor Doutor Fernando Fonseca

Objectivo: analisar a experiência recente em cirurgia estapédica do Hospital Professor Doutor Fernando Fonseca, recorrendo à avaliação dos seus resultados audiométricos. Materiais e métodos: avaliação retrospectiva de processos clínicos referentes a 155 cirurgias estapédicas consecutivas realizadas no Hospital Professor Doutor Fernando Fonseca, entre Janeiro de 2006 e Dezembro de 2010. Resultados: a média de idades foi de 43,6 anos. A média de 4 frequências (0.5, 1, 2 e 4 kHz) do gap aero-ósseo pós- operatório foi de 5,2 dB. O ganho auditivo médio registado foi de 27 dB sendo a taxa de sucesso cirúrgico de 88,2%. A alteração da condução óssea nas altas frequências foi de 4,9 dB. Conclusões: A cirurgia estapédica apresenta uma elevada taxa de sucesso e baixa frequência de complicações, sendo uma opção preferencial no tratamento da otosclerose. Os resultados deste trabalho confirmam-no reforçando o recurso à cirurgia estapédica no Hospital Professor Doutor Fernando Fonseca.

La colecistectomía laparoscópica en el Hospital Vicente Corral Moscoso de Cuenca, 1994-2008

Antecedentes. La colecistectomía laparoscópica (CL, Cole-Lap) es el tratamiento de elección en la patología biliar benigna, la que presenta una elevada incidencia en nuestra ciudad y país. En el hospital Vicente Corral, cirujanos en formación y docentes, han participado en el desarrollo de esta técnica desde su inicio. Objetivo. Describir y compartir la experiencia de 14 años de colecistectomía laparoscópica en el Hospital Vicente Corral M. Métodos. Se presenta la casuística descriptiva y retrospectiva de 2.200 pacientes intervenidos por colecistectomía laparoscópica desde mayo de 1994 hasta enero 2008. Resultados. De 2.200 CL, el 79% son de sexo femenino, con promedio de edad de 43 años, con diagnóstico intraoperatorio de colecistitis crónica litiásica en el 82%. Se presentaron complicaciones entre mayores y menores en el 38%, las perforaciones de vesícula con salida de la bilis y las hemorragias provenientes de la arteria cística fueron las más frecuentes. La lesión de la vía biliar principal se registró en el 0.12%. En las 100 primeras cirugías se presentaron 25 complicaciones, mientras que en las 100 últimas fueron 34. El tiempo operatorio promedio fue de 35 minutos en el 2008. Discusión. La colecistectomía laparoscópica demuestra, en nuestro estudio, ser un procedimiento seguro y efectivo en pacientes con colecistitis calculosa aguda o crónica.