904 resultados para Surgical instruments and apparatus
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BACKGROUND Although surgery represents the cornerstone treatment of endometrial cancer at initial diagnosis, scarce data are available in recurrent setting. The purpose of this study was to review the outcome of surgery in these patients. METHODS Medical records of all patients undergoing surgery for recurrent endometrial cancer at NCI Milano between January 2003 and January 2014 were reviewed. Survival was determined from the time of surgery for recurrence to last follow-up. Survival was estimated using Kaplan-Meier methods. Differences in survival were analyzed using the log-rank test. The Fisher's exact test was used to compare optimal versus suboptimal cytoreduction against possible predictive factors. RESULTS Sixty-four patients were identified. Median age was 66 years. Recurrences were multiple in 38 % of the cases. Optimal cytoreduction was achieved in 65.6 %. Median OR time was 165 min, median postoperative hemoglobin drop was 2.4 g/dl, and median length hospital stay was 5.5 days. Eleven patients developed postoperative complications, but only four required surgical management. Estimated 5-year progression-free survival (PFS) was 42 and 19 % in optimally and suboptimally cytoreduced patients, respectively. At multivariate analysis, only residual disease was associated with PFS. Estimated 5-year overall survival (OS) was 60 and 30 % in optimally and suboptimally cytoreduced patients, respectively. At multivariate analysis, residual disease and histotype were associated with OS. At multivariate analysis, only performance status was associated with optimal cytoreduction. CONCLUSIONS Secondary cytoreduction in endometrial cancer is associated with long PFS and OS. The only factors associated with improved long-term outcome are the absence of residual disease at the end of surgical resection and histotype.
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Despite several improvements in the surgical field and in the systemic treatment, ovarian cancer (OC) is still characterized by high recurrence rates and consequently poor survival. In OC, there is still a great lack of knowledge with regard to cancer behavior and mechanisms of recurrence, progression, and drug resistance. The OC metastatization process mostly occurs via intracoelomatic spread. Recent evidences show that tumor cells generate a favorable microenvironment consisting in T regulatory cells, T infiltrating lymphocytes, and cytokines which are able to establish an "immuno-tolerance mileau" in which a tumor cell can become a resistant clone. When the disease responds to treatment, immunoediting processes and cancer progression have been stopped. A similar inhibition of the immunosuppressive microenvironment has been observed after optimal cytoreductive surgery as well. In this scenario, the early identification of circulating tumor cells could represent a precocious signal of loss of the immune balance that precedes cancer immunoediting and relapse. Supporting this hypothesis, circulating tumor cells have been demonstrated to be a prognostic factor in several solid tumors such as colorectal, pancreatic, gastric, breast, and genitourinary cancer. In OC, the role of circulating tumor cells is still to be defined. However, as opposed to healthy women, circulating tumor cells have been demonstrated in peripheral blood of OC patients, opening a new research field in OC diagnosis, treatment monitoring, and follow-up.
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Research question: International and national sport federations as well as their member organisations are key actors within the sport system and have a wide range of relationships outside the sport system (e.g. with the state, sponsors, and the media). They are currently facing major challenges such as growing competition in top-level sports, democratisation of sports with ‘sports for all’ and sports as the answer to social problems. In this context, professionalising sport organisations seems to be an appropriate strategy to face these challenges and current problems. We define the professionalisation of sport organisations as an organisational process of transformation leading towards organisational rationalisation, efficiency and business-like management. This has led to a profound organisational change, particularly within sport federations, characterised by the strengthening of institutional management (managerialism) and the implementation of efficiency-based management instruments and paid staff. Research methods: The goal of this article is to review the current international literature and establish a global understanding of and theoretical framework for analysing why and how sport organisations professionalise and what consequences this may have. Results and findings: Our multi-level approach based on the social theory of action integrates the current concepts for analysing professionalisation in sport federations. We specify the framework for the following research perspectives: (1) forms, (2) causes and (3) consequences, and discuss the reciprocal relations between sport federations and their member organisations in this context. Implications: Finally, we work out a research agenda and derive general methodological consequences for the investigation of professionalisation processes in sport organisations.
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Introduction: International and national sports federations as well as their member organisations (usually sports clubs) are key actors within the sports system and have a wide range of relationships outside the sports system (e.g. with the state, sponsors, and the media). They are currently facing major challenges such as growing competition in top-‐level sports, democratisation of sports with “sports for all” and sports as the answer to social problems (integration, education, health, unemployment, etc.). In this context, professionalising sports organisations seems to be an appropriate strategy to face these challenges and solve current problems. This has led to a profound organisational change, particularly within sports federations, characterised by the strengthening of institutional management (managerialism) and the implementation of efficiency-‐based management instruments and paid staff. In this context the questions arise how sports organisations professionalise and what consequences this may have. Theoretical framework: The goal of our presentation is to review the international literature and develop an appropriate concept of professionalisation in sport federations. Our multi-‐level approach based on social theory of action integrates the current concepts and perspectives for analysing professionalisation in sports federations. We specify the framework for the following research perspectives: (1) forms, (2) causes and mechanisms, (3) consequences and (4) dynamics, and discuss the reciprocal relations between sports federations and their member organisations in this context. When analysing these different research perspectives, it is important to select or elaborate appropriate theoretical concepts to match the general multi-‐level framework Discussion: The elaborated multi-‐level framework for analysing professionalisation in sports federations is able to integrate most of the existing theoretical concepts and therefore, the broad range of endogenous as well as exogenous factors that might influence the professionalisation of sports organisations. Based on the theoretical framework, we can identify several consequences for the methodological design of studies intending to analyse the different perspectives of professionalisation in sports organisations: Data have to be collected on the different levels. Not only the forms of professionalisation and relevant structures of the organisations should be taken into account but also important characteristics of the environment (macro level) as well as members or member organisations, particularly key actors who might play a crucial role in gaining an understanding of professionalisation processes in sports organisations. In order to carry out a complex organisational research design, it seems necessary to focus on case studies – an approach that has become increasingly important in organisational research. Different strategies and methods of data collection have to be used within the case studies (e.g. interviews with experts within the organisations, questionnaire for selected people in the organisation, document analysis). Therefore, qualitative and quantitative research strategies have to be combined.
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The history of cerebral aneurysm surgery owes a great tribute to the tenacity of pioneering neurosurgeons who designed and developed the clips used to close the aneurysms neck. However, until the beginning of the past century, surgery of complex and challenging aneurysms was impossible due to the lack of surgical microscope and commercially available sophisticated clips. The modern era of the spring clips began in the second half of last century. Until then, only malleable metal clips and other non-metallic materials were available for intracranial aneurysms. Indeed, the earliest clips were hazardous and difficult to handle. Several neurosurgeons put their effort in developing new clip models, based on their personal experience in the treatment of cerebral aneurysms. Finally, the introduction of the surgical microscope, together with the availability of more sophisticated clips, has allowed the treatment of complex and challenging aneurysms. However, today none of the new instruments or tools for surgical therapy of aneurysms could be used safely and effectively without keeping in mind the lessons on innovative surgical techniques provided by great neurovascular surgeons. Thanks to their legacy, we can now treat many types of aneurysms that had always been considered inoperable. In this article, we review the basic principles of surgical clipping and illustrate some more advanced techniques to be used for complex aneurysms.
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BACKGROUND For chronic subdural hematoma, placement of a Blake drain with a two-burr-hole craniotomy is often preferred. However, the placement of such drains carries the risk of penetrating the brain surface or damaging superficial venous structures. OBJECTIVE To describe the use of a Nelaton catheter for the placement of a subdural drain in two-burr-hole trephination for chronic subdural hematoma. METHOD A Nelaton catheter was used to guide placement of a Blake drain into the subdural hematoma cavity and provide irrigation of the hematoma cavity. With the two-burr-hole method, the Nelaton catheter could be removed easily via the frontal burr hole after the Blake drain was in place. RESULTS We used the Nelaton catheters in many surgical procedures and found it a safe and easy technique. This method allows the surgeon to safely direct the catheter into the correct position in the subdural space. CONCLUSIONS This tool has two advantages. First, the use of a small and flexible Nelaton catheter is a safe method for irrigation of a chronic subdural hematoma cavity. Second, in comparison with insertion of subdural drainage alone through a burr hole, the placement of the Nelaton catheter in subdural space is easier and the risk of damaging relevant structures such as cortical tissue or bridging veins is lower. Thus this technique may help to avoid complications when placing a subdural drain.
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STUDY DESIGN Subgroup analysis of the lumbar spinal stenosis (LSS) without degenerative spondylolisthesis diagnostic cohort of the Spine Patient Outcomes Research Trial multicenter randomized clinical trial with a concurrent observational cohort. OBJECTIVE To determine if sedimentation sign on magnetic resonance image can help with LSS treatment decisions. SUMMARY OF BACKGROUND DATA LSS is one of the most common reasons for surgery in the US elderly, but there is a dearth of reliable diagnostic tools that give a clear indication for surgery. Recent studies have suggested that positive sedimentation sign on magnetic resonance image may be a possible prognostic indicator. METHODS All patients with LSS in both the randomized and observational cohorts had imaging-confirmed stenosis, were surgical candidates, and had neurogenic claudication for at least 12 weeks prior to enrollment. Patients were categorized as "mild," "moderate," or "severe" according to stenosis severity. Of the 654 patients with LSS enrolled in Spine Patient Outcomes Research Trial, complete T2-weighted axial and sagittal digitized images of 115 patients were available for retrospective review. An independent orthopedic spine surgeon evaluated these deidentified Digital Imaging and Communications in Medicine files for the sedimentation sign. RESULTS Sixty-six percent (76/115) of patients were found to have a positive sedimentation sign. Those with a positive sedimentation sign were more likely to have stenosis at L2-L3 (33% vs. 10% P=0.016) or L3-L4 76% vs. 51%, P=0.012), and to have severe (72% vs. 33%, P<0.0001) central stenosis (93% vs. 67% P<0.001) at 2 or more concurrent levels (57% vs. 18%, P=0.01). In multivariate models, the surgical treatment effect was significantly larger in the positive sedimentation sign group for Oswestry Disability Index (-16 vs. -7; P=0.02). CONCLUSION A positive sedimentation sign was associated with a small but significantly greater surgical treatment effect for Oswestry Disability Index in patients with symptomatic LSS, after adjusting for other demographic and imaging features. These findings suggest that positive sedimentation sign may potentially be a useful adjunct to help guide an informed treatment choice regarding surgery for LSS. LEVEL OF EVIDENCE 2.
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Unlike infections occurring during periods of chemotherapy-induced neutropenia, postoperative infections in patients with solid malignancy remain largely understudied. The purpose of this population-based study was to evaluate the clinical and economic burden, as well as the relationship of hospital surgical volume and outcomes associated with serious postoperative infection (SPI) – i.e., bacteremia/sepsis, pneumonia, and wound infection – following resection of common solid tumors.^ From the Texas Discharge Data Research File, we identified all Texas residents who underwent resection of cancer of the lung, esophagus, stomach, pancreas, colon, or rectum between 2002 and 2006. From their billing records, we identified ICD-9 codes indicating SPI and also subsequent SPI-related readmissions occurring within 30 days of surgery. Random-effects logistic regression was used to calculate the impact of SPI on mortality, as well as the association between surgical volume and SPI, adjusting for case-mix, hospital characteristics, and clustering of multiple surgical admissions within the same patient and patients within the same hospital. Excess bed days and costs were calculated by subtracting values for patients without infections from those with infections computed using multilevel mixed-effects generalized linear model by fitting a gamma distribution to the data using log link.^ Serious postoperative infection occurred following 9.4% of the 37,582 eligible tumor resections and was independently associated with an 11-fold increase in the odds of in-hospital mortality (95% Confidence Interval [95% CI], 6.7-18.5, P < 0.001). Patients with SPI required 6.3 additional hospital days (95% CI, 6.1 - 6.5) at an incremental cost of $16,396 (95% CI, $15,927–$16,875). There was a significant trend toward lower overall rates of SPI with higher surgical volume (P=0.037). ^ Due to the substantial morbidity, mortality, and excess costs associated with SPI following solid tumor resections and given that, under current reimbursement practices, most of this heavy burden is borne by acute care providers, it is imperative for hospitals to identify more effective prophylactic measures, so that these potentially preventable infections and their associated expenditures can be averted. Additional volume-outcomes research is also needed to identify infection prevention processes that can be transferred from higher- to lower-volume providers.^
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As an interface between the circulatory and central nervous systems, the neurovascular unit is vital to the development and survival of tumors. The malignant brain cancer glioblastoma multiforme (GBM) displays invasive growth behaviors that are major impediments to surgical resection and targeted therapies. Adhesion and signaling pathways that drive GBM cell invasion remain largely uncharacterized. Here we have utilized human GBM cell lines, primary patient samples, and pre-clinical mouse models to demonstrate that integrin αvβ8 is a major driver of GBM cell invasion. β8 integrin is overexpressed in many human GBM cells, with higher integrin expression correlating with increased invasion and diminished patient survival. Silencing β8 integrin in human GBM cells leads to impaired tumor cell invasion due to hyperactivation of the Rho GTPases Rac1 and Cdc42. β8 integrin associates with Rho GDP Dissociation Inhibitor 1 (RhoGDI1), an intracellular signaling effector that sequesters Rho GTPases in their inactive GDP-bound states. Silencing RhoGDI1 expression or uncoupling αvβ8 integrin-RhoGDI1 protein interactions blocks GBM cell invasion due to Rho GTPase hyperactivation. These data reveal for the first time that αvβ8 integrin, via interactions with RhoGDI1, suppresses activation of Rho proteins to promote GBM cell invasiveness. Hence, targeting the αvβ8 integrin-RhoGDI1 signaling axis may be an effective strategy for blocking GBM cell invasion.
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At Ny-Ålesund (78.9° N), Svalbard, surface radiation measurements of up- and downward short- and longwave radiation are operated since August 1992 in the frame of the Baseline Surface Radiation Network (BSRN), complemented with surface and upper air meteorology since August 1993. The long-term observations are the base for a climatological presentation of the surface radiation data. Over the 21-year observation period, ongoing changes in the Arctic climate system are reflected. Particularly, the observations indicate a strong seasonality of surface warming and related changes in different radiation parameters. The annual mean temperature at Ny-Ålesund has risen by +1.3 ± 0.7 K per decade, with a maximum seasonal increase during the winter months of +3.1 ± 2.6 K per decade. At the same time, winter is also the season with the largest long-term changes in radiation, featuring an increase of +15.6 ± 11.6 W/m**2 per decade in the downward longwave radiation. Furthermore, changes in the reflected solar radiation during the months of snow melt indicate an earlier onset of the warm season by about 1 week compared to the beginning of the observations. The online available dataset of Ny-Ålesund surface radiation measurements provides a valuable data source for the validation of satellite instruments and climate models.
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We describe a system designed to re-bunch positron pulses delivered by an accumulator supplied by a positron source and a Surko-trap. Positron pulses from the accumulator are magnetically guided in a 0.085 T field and are injected into a region free of magnetic fields through a μ -metal field terminator. Here positrons are temporally compressed, electrostatically guided and accelerated towards a porous silicon target for the production and emission of positronium into vacuum. Positrons are focused in a spot of less than 4 mm FWTM in bunches of ∼8 ns FWHM. Emission of positronium into the vacuum is shown by single shot positron annihilation lifetime spectroscopy.
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The paper explores the effects of birth order and sibling sex composition on human capital investment in children in India using the Indian Human Development Survey (IHDS). Endogeneity of fertility is addressed using instruments and controlling for household fixed effects. Family size effect is also distinguished from the sibling sex composition effect. Previous literature has often failed to take endogeneity into account and shows a negative birth order effect for girls in India. Once endogeneity of fertility is addressed, there is no evidence for a negative birth order effect or sibling sex composition effect for girls. Results show that boys are worse off in households that have a higher proportion of boys specifically when they have older brothers.
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ObjectKineticMonteCarlo models allow for the study of the evolution of the damage created by irradiation to time scales that are comparable to those achieved experimentally. Therefore, the essential ObjectKineticMonteCarlo parameters can be validated through comparison with experiments. However, this validation is not trivial since a large number of parameters is necessary, including migration energies of point defects and their clusters, binding energies of point defects in clusters, as well as the interactionradii. This is particularly cumbersome when describing an alloy, such as the Fe–Cr system, which is of interest for fusion energy applications. In this work we describe an ObjectKineticMonteCarlo model for Fe–Cr alloys in the dilute limit. The parameters used in the model come either from density functional theory calculations or from empirical interatomic potentials. This model is used to reproduce isochronal resistivity recovery experiments of electron irradiateddiluteFe–Cr alloys performed by Abe and Kuramoto. The comparison between the calculated results and the experiments reveal that an important parameter is the capture radius between substitutionalCr and self-interstitialFe atoms. A parametric study is presented on the effect of the capture radius on the simulated recovery curves.
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The lattice order degree and the strain in as-grown, Mn-implanted and post-implantedannealedInAsthinfilms were investigated with depth resolution by means of Rutherford backscattering spectrometry in channeling conditions (RBS/C). Three main crystallographic axes were analyzed for both In and As sublattices. The behaviour of the induced defects was evaluated in two regions with different native defects: the interface and the surface. The results show that Mn implantation and post-implantation annealing are anisotropic processes, affecting in a different way the In and As sublattices. The mechanisms influencing the enhancement and deterioration of the crystal quality during the implantation are discussed in relation to the as-grown defects and the segregation of the elements
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Rotator cuff tears of the shoulder are a common cause of pain and disability. Although surgery is frequently beneficial, re-tearing of the tendons is likely to re-occur. In many cases even if the reparation is successful it will still generate discomfort, problems with mobility, as well as a sharp pain. This project is funded in the cooperation with the Hospital Clinico San Carlos de Madrid. The purpose of this work is to analyze the effect of the surgical repair and the application of different therapies, including mesenchymal stem cell therapy on the biomechanical properties (strength and stiffness) of the repaired tendon. An animal model of rotator cuff tendon reparations has been developed on laboratory rats.To obtain the mechanical response of the healthy and repaired tendons, it was necessary to develop an experimental set up to reproduce the in-vivo working conditions of the tendons (37 ºC, immersed in physiological serum), and especially the load transfer. The biomechanical properties (maximum load and stiffness) have been measured in healthy and repaired tendons. A total of 70 rats are used in this particular study. It has been found that the repaired tendon is stronger than the original on. However, the repaired tendons demonstrate less flexibility than the healthy (original) ones prior to the damage