Análisis del desgaste de la articulación cabeza femoral-copa acetabular mediante simulación experimental con máquina perno-disco

Este trabajo presenta un estudio que permite establecer la vida útil esperada de un sistema prostético de cadera para el caso del fenotipo mexicano. En primera instancia se determinó la distancia total equivalente de deslizamiento y las condiciones de carga entre el componente femoral y la copa acetabular bajo condiciones normales de carga. Posteriormente, se desarrolló una simulación experimental para la realización de un ensayo tribológico en una máquina de desgaste del tipo Perno sobre Disco (Pin on Disk, POD). Este ensayo sometió al conjunto fabricado en acero inoxidable AISI-ASTM 316L, las probetas del componente femoral y polietileno de alta densidad, el componente acetabular, a condiciones de desgaste equivalentes a un uso cotidiano de diez años. Con respecto a la distribución de las cargas por aplicar en el desarrollo experimental, se empleó el método del elemento finito para realizar una simulación numérica de las condiciones de operación del conjunto y así determinar los esfuerzos correspondientes en la zona de interés. El ensayo tribológico realizado permitió evaluar la pérdida volumétrica de materiales del sistema analizado. Al comparar los resultados obtenidos con los reportados en la literatura, se puede establecer que en principio se valida el procedimiento planteado en este trabajo, lo que permitirá establecer con certidumbre la vida esperada de una prótesis de cadera. Se propone desarrollar un trabajo posterior que valida estadísticamente la metodología propuesta. Palabras clave: vida útil; componente femoral; copa acetabular; fenotipo mexicano; configuración Perno-Disco (POD

Wear analysis by applying a pin-disc configuration to phemoral head and acetabular cup

This work determines a prosthetic hip system’s life-span, focusing on a Mexican phenotype. The total sliding equivalent distance for the system was determined, as well as the loading regime under which the femoral component and the acetabular cup were subjected in normal operating conditions. An experimental tribology essay was then performed to simulate the wearing of the components in a Pin over Disc machine. This assay (for which the test specimens were manufactured in medical grade stainless steel AISI-ASTM 316L for the femoral component and high density polyethylene for the acetabular cup) was aimed at simulating wear conditions involved in 10 years of continuous operation. A numerical simulation of operational conditions (using the finite element method) was performedIn for establishing assay loading conditions to accurately determine where the loads should be applied. The tribology assay led to quantifying the volumetric loss of materials for the system being analysed. It can be concluded that the methodology proposed in this work for estimating the life-span of a prosthetic hip system was valid and accurate by comparing the results with those found in the literature. A statistical validation of the proposed method is plaaned for the future. Key words: Design life; femoral component; acetabular cup; Mexican phenotype; pin-disc configuration.Este trabajo presenta un estudio que permite establecer la vida útil esperada de un sistema prostético de cadera para el caso del fenotipo mexicano. En primera instancia se determinó la distancia total equivalente de deslizamiento y las condiciones de carga entre el componente femoral y la copa acetabular bajo condiciones normales de carga. Posteriormente, se desarrolló una simulación experimental para la realización de un ensayo tribológico en una máquina de desgaste del tipo Perno sobre Disco (Pin on Disk, POD). Este ensayo sometió al conjunto fabricado en acero inoxidable AISI-ASTM 316L, las probetas del componente femoral y polietileno de alta densidad, el componente acetabular, a condiciones de desgaste equivalentes a un uso cotidiano de diez años. Con respecto a la distribución de las cargas por aplicar en el desarrollo experimental, se empleó el método del elemento finito para realizar una simulación numérica de las condiciones de operación del conjunto y así determinar los esfuerzos correspondientes en la zona de interés. El ensayo tribológico realizado permitió evaluar la pérdida volumétrica de materiales del sistema analizado. Al comparar los resultados obtenidos con los reportados en la literatura, se puede establecer que en principio se valida el procedimiento planteado en este trabajo, lo que permitirá establecer con certidumbre la vida esperada de una prótesis de cadera. Se propone desarrollar un trabajo posterior que valida estadísticamente la metodología propuesta. Palabras clave: vida útil; componente femoral; copa acetabular; fenotipo mexicano; configuración Perno-Disco (POD

Wear analysis by applying a pin-disc configuration to phemoral head and acetabular cup Análisis del desgaste de la articulación cabeza femoral–copa acetabular mediante simulación experimental con máquina perno-disco

This work determines a prosthetic hip system’s life-span, focusing on a Mexican phenotype. The total sliding equivalent distance for the system was determined, as well as the loading regime under which the femoral component and the acetabular cup were subjected in normal operating conditions. An experimental tribology essay was then performed to simulate the wearing of the components in a Pin over Disc machine. This assay (for which the test specimens were manufactured in medical grade stainless steel AISI-ASTM 316L for the femoral component and high density polyethylene for the acetabular cup) was aimed at simulating wear conditions involved in 10 years of continuous operation. A numerical simulation of operational conditions (using the finite element method) was performedIn for establishing assay loading conditions to accurately determine where the loads should be applied. The tribology assay led to quantifying the volumetric loss of materials for the system being analysed. It can be concluded that the methodology proposed in this work for estimating the life-span of a prosthetic hip system was valid and accurate by comparing the results with those found in the literature. A statistical validation of the proposed method is plaaned for the future.&#13; &#13; Key words: Design life; femoral component; acetabular cup; Mexican phenotype; pin-disc configuration.<br>Este trabajo presenta un estudio que permite establecer la vida útil esperada de un sistema prostético de cadera para el caso del fenotipo mexicano. En primera instancia se determinó la distancia total equivalente de deslizamiento y las condiciones de carga entre el componente femoral y la copa acetabular bajo condiciones normales de carga. Posteriormente, se desarrolló una simulación experimental para la realización de un ensayo tribológico en una máquina de desgaste del tipo Perno sobre Disco (Pin on Disk, POD). Este ensayo sometió al conjunto fabricado en acero inoxidable AISI-ASTM 316L, las probetas del componente femoral y polietileno de alta densidad, el componente acetabular, a condiciones de desgaste equivalentes a un uso cotidiano&#13; de diez años. Con respecto a la distribución de las cargas por aplicar en el desarrollo experimental, se empleó el método del elemento finito para realizar una simulación numérica de las condiciones de operación del conjunto y así determinar los esfuerzos correspondientes en la zona de interés. El ensayo tribológico realizado permitió evaluar la pérdida volumétrica de materiales del sistema analizado. Al comparar los resultados obtenidos con los reportados en la literatura, se puede establecer que en principio se valida el procedimiento planteado en este trabajo, lo que permitirá establecer con certidumbre la vida esperada de una prótesis de cadera. Se propone desarrollar un trabajo posterior que valida estadísticamente la metodología propuesta.&#13; &#13; Palabras clave: vida útil; componente femoral; copa acetabular; fenotipo mexicano; configuración Perno-Disco (POD

Memoria del primer foro sobre logros, problemas y propuestas de los cuerpos académicos de educación y humanidades de la Universidad Autónoma del Estado de México

Motivados por el interés de dialogar nuestras preocupaciones cotidianas en torno al quehacer académico en la Universidad, e impulsados por la inquietud de compartir puntos de vista y apreciaciones acerca de la forma en que organizamos colectivamente el trabajo académico (en especial, de investigación) en los diferentes espacios de especialización disciplinaria e interdisciplinaria en los campos de las Ciencias de la Educación y las Humanidades, asistimos a la convocatoria para reflexionar qué tanto hemos avanzado como verdaderos equipos de trabajo (sobre todo en lo relativo a la investigación) y cuánto aún nos queda por hacer, a fin de coordinar esfuerzos individuales y sumar capacidades en proyectos y actividades comunes a cada cuerpo académico

Evaluation of a quality improvement intervention to reduce anastomotic leak following right colectomy (EAGLE): pragmatic, batched stepped-wedge, cluster-randomized trial in 64 countries

Background Anastomotic leak affects 8 per cent of patients after right colectomy with a 10-fold increased risk of postoperative death. The EAGLE study aimed to develop and test whether an international, standardized quality improvement intervention could reduce anastomotic leaks. Methods The internationally intended protocol, iteratively co-developed by a multistage Delphi process, comprised an online educational module introducing risk stratification, an intraoperative checklist, and harmonized surgical techniques. Clusters (hospital teams) were randomized to one of three arms with varied sequences of intervention/data collection by a derived stepped-wedge batch design (at least 18 hospital teams per batch). Patients were blinded to the study allocation. Low- and middle-income country enrolment was encouraged. The primary outcome (assessed by intention to treat) was anastomotic leak rate, and subgroup analyses by module completion (at least 80 per cent of surgeons, high engagement; less than 50 per cent, low engagement) were preplanned. Results A total 355 hospital teams registered, with 332 from 64 countries (39.2 per cent low and middle income) included in the final analysis. The online modules were completed by half of the surgeons (2143 of 4411). The primary analysis included 3039 of the 3268 patients recruited (206 patients had no anastomosis and 23 were lost to follow-up), with anastomotic leaks arising before and after the intervention in 10.1 and 9.6 per cent respectively (adjusted OR 0.87, 95 per cent c.i. 0.59 to 1.30; P = 0.498). The proportion of surgeons completing the educational modules was an influence: the leak rate decreased from 12.2 per cent (61 of 500) before intervention to 5.1 per cent (24 of 473) after intervention in high-engagement centres (adjusted OR 0.36, 0.20 to 0.64; P &lt; 0.001), but this was not observed in low-engagement hospitals (8.3 per cent (59 of 714) and 13.8 per cent (61 of 443) respectively; adjusted OR 2.09, 1.31 to 3.31). Conclusion Completion of globally available digital training by engaged teams can alter anastomotic leak rates. Registration number: NCT04270721 (http://www.clinicaltrials.gov)

Global variation in postoperative mortality and complications after cancer surgery: a multicentre, prospective cohort study in 82 countries

© 2021 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY-NC-ND 4.0 licenseBackground: 80% of individuals with cancer will require a surgical procedure, yet little comparative data exist on early outcomes in low-income and middle-income countries (LMICs). We compared postoperative outcomes in breast, colorectal, and gastric cancer surgery in hospitals worldwide, focusing on the effect of disease stage and complications on postoperative mortality. Methods: This was a multicentre, international prospective cohort study of consecutive adult patients undergoing surgery for primary breast, colorectal, or gastric cancer requiring a skin incision done under general or neuraxial anaesthesia. The primary outcome was death or major complication within 30 days of surgery. Multilevel logistic regression determined relationships within three-level nested models of patients within hospitals and countries. Hospital-level infrastructure effects were explored with three-way mediation analyses. This study was registered with ClinicalTrials.gov, NCT03471494. Findings: Between April 1, 2018, and Jan 31, 2019, we enrolled 15 958 patients from 428 hospitals in 82 countries (high income 9106 patients, 31 countries; upper-middle income 2721 patients, 23 countries; or lower-middle income 4131 patients, 28 countries). Patients in LMICs presented with more advanced disease compared with patients in high-income countries. 30-day mortality was higher for gastric cancer in low-income or lower-middle-income countries (adjusted odds ratio 3·72, 95% CI 1·70–8·16) and for colorectal cancer in low-income or lower-middle-income countries (4·59, 2·39–8·80) and upper-middle-income countries (2·06, 1·11–3·83). No difference in 30-day mortality was seen in breast cancer. The proportion of patients who died after a major complication was greatest in low-income or lower-middle-income countries (6·15, 3·26–11·59) and upper-middle-income countries (3·89, 2·08–7·29). Postoperative death after complications was partly explained by patient factors (60%) and partly by hospital or country (40%). The absence of consistently available postoperative care facilities was associated with seven to 10 more deaths per 100 major complications in LMICs. Cancer stage alone explained little of the early variation in mortality or postoperative complications. Interpretation: Higher levels of mortality after cancer surgery in LMICs was not fully explained by later presentation of disease. The capacity to rescue patients from surgical complications is a tangible opportunity for meaningful intervention. Early death after cancer surgery might be reduced by policies focusing on strengthening perioperative care systems to detect and intervene in common complications. Funding: National Institute for Health Research Global Health Research Unit

Effects of hospital facilities on patient outcomes after cancer surgery: an international, prospective, observational study

© 2022 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 licenseBackground: Early death after cancer surgery is higher in low-income and middle-income countries (LMICs) compared with in high-income countries, yet the impact of facility characteristics on early postoperative outcomes is unknown. The aim of this study was to examine the association between hospital infrastructure, resource availability, and processes on early outcomes after cancer surgery worldwide. Methods: A multimethods analysis was performed as part of the GlobalSurg 3 study—a multicentre, international, prospective cohort study of patients who had surgery for breast, colorectal, or gastric cancer. The primary outcomes were 30-day mortality and 30-day major complication rates. Potentially beneficial hospital facilities were identified by variable selection to select those associated with 30-day mortality. Adjusted outcomes were determined using generalised estimating equations to account for patient characteristics and country-income group, with population stratification by hospital. Findings: Between April 1, 2018, and April 23, 2019, facility-level data were collected for 9685 patients across 238 hospitals in 66 countries (91 hospitals in 20 high-income countries; 57 hospitals in 19 upper-middle-income countries; and 90 hospitals in 27 low-income to lower-middle-income countries). The availability of five hospital facilities was inversely associated with mortality: ultrasound, CT scanner, critical care unit, opioid analgesia, and oncologist. After adjustment for case-mix and country income group, hospitals with three or fewer of these facilities (62 hospitals, 1294 patients) had higher mortality compared with those with four or five (adjusted odds ratio [OR] 3·85 [95% CI 2·58–5·75]; p<0·0001), with excess mortality predominantly explained by a limited capacity to rescue following the development of major complications (63·0% vs 82·7%; OR 0·35 [0·23–0·53]; p<0·0001). Across LMICs, improvements in hospital facilities would prevent one to three deaths for every 100 patients undergoing surgery for cancer. Interpretation: Hospitals with higher levels of infrastructure and resources have better outcomes after cancer surgery, independent of country income. Without urgent strengthening of hospital infrastructure and resources, the reductions in cancer-associated mortality associated with improved access will not be realised. Funding: National Institute for Health and Care Research