Influència de l'alçada protèsica en la capacitat de consolidació de les tuberositats en les hemiartroplàsties per fractures de l'húmer proximal

Descripció del recurs: 2 febrer 2010Estudis recents posen de manifest que la consolidació de les tuberositats en les hemiartroplàsties implantades per fractura de húmer proximal és el factor anatòmic més determinant en el resultat funcional de les mateixes. En el acte quirúrgic, la manca de referències anatòmiques provocades per la propia fractura condiciona que la implantació aquestes pròtesis sigui sovint imprecisa amb errors alçada. Els canvis en alçada de implant han estat avaluats sota el concepte de produir pinçament en el cas augmentar alçada del component i de debilitar el braç de palanca del deltoides en el cas de disminuir alçada, no han estat però estudiats sota el concepte de que canvis en alçada implantació de la pròtesi condicionen canvis en elongació dels tendons de la còfia rotadora, i per tant, canvis en les tensions de sutura de les tuberositats entre elles i amb la diàfisi, comprometent per tant la seva capacitat de consolidació. Hipòtesi de treball Els canvis en alçada de implant no condicionen variacions en elongació dels muscles de la còfia rotadora que comportin canvis en les tensions de les sutures de les tuberositats a la diàfisi humeral. Objectius 3.2.1 Determinar quina és la tendència alçada en la implantació de les hemiartroplàsties per fractura. 3.2.2 Analitzar quins són els resultats clínics funcionals de les hemiartroplàsties per fractura de húmer proximal segons alçada implantació. 3.2.3 Analitzar quins són els canvis en les tensions entre les sutures de les tuberositats entre elles i amb la diàfisi humeral en canviar alçada de implant en un model estàtic. 3.2.4 Analitzar quins son els canvis en les tensions entre les sutures de les tuberositats entre elles i amb la diàfisi humeral en canviar alçada de implant en un model dinàmic. El treball sobre la influència de la alçada en les hemiartroplàsties per fractura del terç proximal de húmer es composa de tres estudis diferents. En primer lloc es va realitzar un estudi clínic sobre 25 pacients, un segon estudi anatòmic, realitzat al Departament Anatomia de la Universitat Autònoma de Barcelona, en el qual sobre quatre preparacions anatòmiques es va collocar una hemiartroplàstia en diferents posicions alçada, i es van reproduir les sutures, sobre les quals es collocaren unes galgues que mesuraven la tensió que passava per les mateixes en aplicar una força de tracció sobre els tendons del manegot de rotadors (forces de tracció constant a través un mecanisme de manovella). I un tercer estudi que es va realitzar al Centre de Recerca Enginyeria Biomèdica de la Universitat Politècnica de Catalunya, mitjançant un robot dissenyat per a realitzar els moviments de espatlla sobre un fantomas al que se li colloca una hemiartroplàstia en diferents posicions alçada, i amb les mateixes galgues es mesura la tensió en les diferents sutures. Els resultats clínics que hem obtingut en el nostre estudi concorden essencialment amb aquells descrits a la literatura. la hemiartroplàstia en el tractament de les fractures de húmer proximal constitueix un tractament efectiu per a prevenir el dolor. Globalment, el moviment en un alt nombre de casos queda molt reduït, sobre tot elevació anterior, abducció i rotació externa. Des de un punt de vista estàtic, que vindria a ésser representat per la situació de repòs o de immobilització postoperatòria, les sutures realitzades entre les dues tuberositats i entre la tuberositat gran i la diàfisi son les que més a risc estan de trencar, i el seu trencament es el que més en risc posa la capacitat de consolidació de la tuberositat gran. En estudi dinàmic, en analitzar les fases del moviment i els cicles, observem que globalment la sutura que en major nombre ocasions trenca és la que registra el sensor 3, és a dir, la que uneix la tuberositat gran amb la diàfisi, i la configuració en la que trenca en el 100% de casos és la baixa. Conclusions sobre la hipòtesi de treball o conclusions principals Els canvis en alçada del component humeral en les hemiartroplàsties implantades per fractures complexes del húmer proximal condicionen variacions en les tensions de les sutures entre les tuberositats i entre les tuberositats i la diàfisi humeral. Conclusions sobre els objectius o conclusions accessòries 8.2.1 En la implantació de les hemiartroplàsties per fractura del húmer proximal hi ha una tendència a implantar el component humeral en una situació més baixa, comportant un escurçament de la longitud total humeral. 8.2.2. Els resultats clínics funcionals de les hemiartroplàsties implantades per fractura del húmer proximal son pitjors al implantar la pròtesi en una situació més baixa. 8.2.3. En un model estàtic, la sutura a més risc es la que uneix les tuberositats entre si, i el risc de ruptura es major al implantar la pròtesi en una situació més baixa que la anatòmica. 8.2.4. En un model dinàmic es produeix al inici del moviment un fenomen encaix que difereix segons la alçada a la que ha implantat la pròtesi i que comporta canvis en les tensions entre les sutures. 8.2.5. En les diferents fases del moviment (elevació anterior, rotació externa i rotació interna) les tensions entre les sutures varien de manera diferent segons alçada a la qual es deixa el component humeral.Recent studies show that tuberosity healing in hemiarthroplasties implanted in proximal humeral fractures is the most important anatomical factor of functional outcome. Surgical scenario gives no landmarks to properly position the prostheses in terms of height giving frequent errors. The changes in proper height of the implant have been subject of study because the impingement produced when increasing the height and because the shortening of the deltoid arm when decreasing total height, but no studies have been conducted to evaluate the effect of changing prostheses height on tuberosity suture tension and healing capacity. Hypothesis Changes of the prostheses height do not affect the tension thru the sutures of the tuberosities. Objectives 1 Observe the tendency of height implantation of hemiarthroplasties in proximal humeral fractures. 2 Determine functional outcomes of hemiarthroplasties in proximal humeral fractures at different heights. 3 Determine tension changes through tuberosity sutures in a static model at different prostheses heights. 4 Determine tension changes through tuberosity sutures in a dynamic model at different prostheses heights. The study of the influence of height in hemiarthroplasties in fractures of the proximal humerus includes three different works. First of all a clinical study was performed in 25 patients, secondly an anatomical study was carried out in the Anatomical Department of the Universitat Autònoma de Barcelona with 4 cadaveric specimens to which a hemiarthroplasty was implanted en several different positions according height suturing tuberosities back to the prostheses with an specially developed system to measure tension among sutures when a traction was applied passing through rotator cuff tendons. The third study was carried out in the Centre de Recerca Enginyeria Biomèdica de la Universitat Politècnica de Catalunya and with a robotic aid normal shoulder movements were reproduced on a humeral sawbone with a hemiarthoplasty implanted at different heights. The same tension register system was applied to measure tension among different sutures. Clinical results obtained in the study are in concordance with those published in the literature. Hemiarthroplasty for the treatment of proximal humeral fractures constitutes an effective treatment to prevent pain. Globally, movement is reduced most of the times, principally anterior elevation, abduction and external rotation. From the static point of view, represented by the immobilized arm after surgery, the sutures running through both tuberosities and between the greater tuberosity and the dyaphisis are the ones at risk of breakage and its breakage puts on risk tuberosity consolidation. In the dynamic study, when analyzing the three parts of the movement and the cycles, we could observe that globally the suture that breaks most of the times is the one that runs between greater tuberosity and dyaphisis and that placing the prostheses in a low position also increases the breakage risk. Conclusions Changing the height of the humeral component in hemiarthroplasties implanted because proximal humeral fractures produces changes in the tensions registered in the sutures running through the tuberosities and between the tuberosities and the dyaphisis. Secondary Conclusions 1 When implanting a hemiarthroplasty in a proximal humeral fractures there is a tendency to implant the humeral component in a low position, reducing total humeral length. 2. Functional clinical results of hemiarthroplasties implanted because proximal humeral fracture are worst when the prostheses is implanted in a lower position. 3. In a static model, the suture at risk is the one that runs between the tuberosyties and the risk of breakage is higher when the prostheses is implanted in a lower position. 4. In a dynamic model an accommodation phenomena is present when the movement starts and is different depending on the height of the prostheses implanted and affects the tensions registered through the sutures

Reduced scale feasibility of temperature rise tests in substation connectors

Due to the important increase of the power of electrical transmission and distribution grids expected for the following years, especially in developing countries such as Kenya, Brazil, Philippines or Mexico among others, that have planes of generating energy from clean sources far away from the centres of consumption [1] it becomes a matter of special importance adapting and developing new substation connectors’ testing methods according to the power and temperature regimes at which they are expected to work. The international normative frame of substation connectors established both by the International Electrotechnical Committee (IEC) [2] and the National Electrical Manufacturers Association (NEMA) [3] sets standardized tests for the evaluation of high voltage connectors. These tests are routinely done within the quality plans of the manufacturers. At the moment, testing of substation connectors –and in general switchgear and fittings- is time demanding and costly due to the energy consumed by such tests. The expectations for the following years are that the power consumption of these tests will not do nothing but grow due to expected increase of power of worldwide overhead lines. For instance, today temperature rise tests in substation connectors involve power ranges up to 100 kVA, which are applied in cycles that can last several weeks. These tests are only feasible in few laboratories and at a very high cost: temporary, monetary, energetic and environmental. For this reason, following the line of other technologies such as aeronautics, naval engineering, or automotive as well as other studies done in the field of electrical engineering specially related to the corona effect [4], this study proposes to develop a reduced scale test system to perform temperature rise tests for substation connectors. Both, a theoretical framework based on analytical formulas, finite element method (FEM) simulations and experimental data has been developed to conduct reduced scale temperature rise tests and to set the conditions at which they provide comparable results to those attained in the original scale tests. Firstly, two circular loops (original and reduced scale loops) composed of a power conductor and two terminal connectors were analysed. The aim of this first study was to determine in an easy and trustful way the voltage and current values to be applied in experimental reduced scale tests to achieve the same steady-state temperature as in the original scale temperature rise test. The scale relationship between tests was set in 1:1.8, although the method proposed in this study can deal with any other scale factor. This study was useful in order to have a first sight of the final results of the procedure using substation connectors.Postprint (published version

Simplification and cost reduction of visual corona tests

Peer ReviewedPostprint (author's final draft

Transient thermal modelling of substation connectors by means of dimensionality reduction

This paper proposes a simple, fast and accurate simulation approach based on one-dimensional reduction and the application of the finite difference method (FDM) to determine the temperatures rise in substation connectors. The method discretizes the studied three-dimensional geometry in a finite number of one-dimensional elements or regions in which the energy rate balance is calculated. Although a one-dimensional reduction is applied, to ensure the accuracy of the proposed transient method, it takes into account the three-dimensional geometry of the analyzed system to determine for all analyzed elements and at each time step different parameters such as the incremental resistance of each element or the convective coefficient. The proposed approach allows fulfilling both accuracy and low computational burden criteria, providing similar accuracy than the three-dimensional finite element method but with much lower computational requirements. Experimental results conducted in a high-current laboratory validate the accuracy and effectiveness of the proposed method and its usefulness to design substation connectors and other power devices and components with an optimal thermal behavior.Postprint (published version

A atividade legislativa municipal e sua efetividade

As atividades legislativas organizadas dentro do arcabouço institucional do parlamento municipal de Curitiba-PR são inúmeras, impulsionadas não apenas pela necessidade de solução de demandas da população, mas são importantes elementos da conexão e das trocas que se estabelecem entre os representantes políticos, os representantes e o poder executivo. Os requerimentos, as indicações, os projetos de lei, as homenagens, cada tipo de ação parlamentar é provocada por diferentes ambições. Cada uma delas traz o seu significado e todas elas são necessárias à performance parlamentar. Por outro lado, os vereadores carecem de participação nas Audiências e Consultas Públicas e outros mecanismos de aprimoramento constitucional que possibilita a sociedade organizada opinar e alterar a discussão e encaminhamento das políticas públicas, principalmente no que se refere à construção do Orçamento Público Municipal. Os vereadores desenvolvem laços mais duradouros que trocas eleitorais em sua prática corriqueira, estabelecendo que se denomina conexão político-representativa, mas não desenvolvem participação efetiva nas grandes questões que realmente conduzem e definem a feição da administração pública municipal

A representação política feminina na Câmara Municipal de Curitiba: “MULHER” OU “MULHERES”? - um estudo de caso

A partir da concepção de representação política elaborada por Judith Butler, refletimos sobre a produção legislativa das Vereadoras da Câmara Municipal de Curitiba, pretendendo com esta abordagem a atualidade da discussão sobre o feminismo, suas concepções e a prática concreta feminina de representantes parlamentares que, a nosso ver, resulta em projetos de lei e em leis que, se por um lado não são específicas para as mulheres, mas apresentam o propósito de localizá-las em determinados papéis sociais, dentro do todo social em que se inserem. As Vereadoras da Câmara Municipal de Curitiba representam a população em geral, e entre os vários setores, questionamos se as organizações de mulheres conseguem fazer valer seus direitos, se estão organizadas suficientemente para isso, se há uma identidade feminina a ser representada A precariedade da representação feminina no parlamento municipal indica, a partir da crítica de Butler, que não há um sujeito estável do feminismo, mas a categoria mulher está diluída em outros papéis sociais e contingências

Melanosis coli. Un caso interesante

Melanosis coli is a benign condition characterized by dark pigmentation of the colonic mucosa as a result of chronic use of anthraquinone laxatives (cascara, sennosides, buckthorn, etc.). A 60 year-old female patient, apparently healthy, who underwent a hysterectomy 31 years ago for fibromatosis, and with frequent and prolonged use of laxatives, starts with lower gastrointestinal symptoms, abdominal cramps, stools with mucus, without blood, without straining or urgency. Therefore, it was decided to perform an endoscopic and histological study of the colon to implement the appropriate treatment.La melanosis coli es una condición benigna caracterizada por la pigmentación oscura de la mucosa colónica como consecuencia del uso crónico de laxantes con antraquinona (cáscara sagrada, senósidos, frángula, etc.). Se presenta una paciente de 60 años de edad, antecedentes de aparente salud anterior, histerectomizada hace 31 años por fibromatosis y con uso frecuente y prolongado de laxantes que comenzó con síntomas digestivos bajos, cólicos abdominales y deposiciones con flema, sin sangre, sin pujos ni tenesmos, por lo que se decidió realizar un estudio endoscópico e histológico del colon para indicar la  terapéutica adecuada

Políticas públicas de desarrollo territorial rural: Instrumentos para enfrentar la crisis

The current global crisis scenario, aggravated by the emergence generated by COVID-19 pandemic, has shown the need for a multidimensional look at the serious problems of society. This article emphasizes the main conceptual contributions of the territorial approach for its application in public policies and presents a set of recommendations for the construction of innovative public policies for rural development, in the situation of the post-pandemic context. It values the importance of incorporating this approach into development policies as a knowledge tool capable of supporting measures to manage the crisis, from the perspective of compliance with the 2030 Agenda for Sustainable Development.El actual escenario de crisis global, agravado por la emergencia de la pandemia del COVID-19, ha evidenciado la necesidad de una mirada multidimensional sobre los graves problemas de la sociedad. Este artículo enfatiza los principales aportes conceptuales del abordaje territorial para su aplicación en las políticas públicas y presenta un conjunto de recomendaciones para la construcción de políticas públicas innovadoras de desarrollo rural, en el ámbito del contexto post pandemia. Valoriza la importancia de la incorporación de este enfoque en las políticas de desarrollo como una herramienta del conocimiento capaz de apoyar las medidas de enfrentamiento a la crisis, desde la perspectiva del cumplimento de la Agenda 2030 del Desarrollo Sostenible

Lipoma submucoso del colon. A propósito de un caso

Colon lipomas are the second most common benign tumors in the colon (0.2%), after the adenomas. They are the most frequent non-epithelial (mesenchymal) tumors in the colon.  The colonic enema can be used for its diagnosis, but the use of colonoscopy enables us to achieve a histological diagnosis and a curative treatment of this disease with minimal risk and overall improvement of the patient. The following work shows the above stated. A 62-year-old mixed-race patient, suffering from lower gastrointestinal symptoms was admitted. A colonoscopy was conducted and a smooth rounded lesion of about 3cm in diameter was detected in the left colon.  An excision was performed and the sample was sent for histological study. The patient evolved successfully until discharge from the outpatient department in a 2 weeks period.Los lipomas de colon ocupan el segundo lugar, después de los adenomas, dentro de los tumores benignos del colon (0.2%) y son los tumores no epiteliales (mesenquimatosos) más frecuentes en este órgano. Para su diagnóstico se puede utilizar el colon por enema, pero el uso de la colonoscopia permite llegar al diagnóstico histológico y al tratamiento curativo de esta enfermedad con el mínimo de riesgos y la mejoría total del paciente. El siguiente trabajo demuestra lo anteriormente planteado: se recibió un paciente de 62 años de edad, mestizo, aquejado de síntomas digestivos bajos, al que se le practicó una colonoscopia y se le detectó una lesión lisa, redondeada, de aproximadamente 3cms de diámetro en colon izquierdo; se le realizó exéresis y se envió la muestra para su estudio histológico, evolucionó satisfactoriamente hasta su egreso a la consulta externa, en el período de dos semanas