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Roughly 10% of the world’s population has chronic kidney disease (CKD). In its advanced stages, CKD greatly increases the risk of hospitalization and death. Although kidney transplantation has revolutionized the care of advanced CKD, clinicians have limited ways of assessing donor kidney quality. Thus, optimal donor kidney–recipient matching cannot be performed, meaning that some patients receive damaged kidneys that function poorly. Fibrosis is a form of chronic damage often present in donor kidneys, and it is an important predictor of future renal function. Currently, no safe, easy-to-perform technique exists that accurately quantifies renal fibrosis. We describe a potentially novel photoacoustic (PA) imaging technique that directly images collagen, the principal component of fibrotic tissue. PA imaging noninvasively quantifies whole kidney fibrotic burden in mice, and cortical fibrosis in pig and human kidneys, with outstanding accuracy and speed. Remarkably, 3-dimensional PA imaging exhibited sufficiently high resolution to capture intrarenal variations in collagen content. We further show that PA imaging can be performed in a setting that mimics human kidney transplantation, suggesting the potential for rapid clinical translation. Taken together, our data suggest that PA collagen imaging is a major advance in fibrosis quantification that could have widespread preclinical and clinical impact.

The Standardized Reporting of Machine Learning Applications in Urology (STREAM-URO) framework was developed to provide a set of recommendations to help standardize how machine learning studies in urology are reported. This framework serves three purposes: (1) to promote high-quality studies and streamline the peer review process; (2) to enhance reproducibility, comparability, and interpretability of results; and (3) to improve engagement and literacy of machine learning within the urological community.

Introduction: Percutaneous nephrolithotomy (PCNL) is the gold standard treatment for patients with a large stone burden. There are a variety of methods to teach this important endourologic procedur...

Background Little evidence exists regarding optimal peritoneal dialysis (PD) access insertion pathways, benchmarking for patency targets, and definitions of access dysfunction. Methods This quality improvement (QI) project evaluated patients with PD catheters inserted at a single center in Toronto, Canada, following: establishment of PD catheter insertion protocols, a PD access coordinator, PD access operator training, and outcomes reporting. We define primary vs secondary PD catheter dysfunction by presentation before/after initial home PD treatment. We report catheter dysfunction rates, interventions restoring PD catheter patency (interventional radiology [IR] vs advanced laparoscopic [AL]) (embedded vs non-embedded) between 2012 and 2017. Results A total of 297 first PD catheters were inserted between January 2012 and December 2017. Interventional radiology PD catheters ( n = 94) were placed in older patients with greater comorbidities and less prior abdominal surgery than AL-placed catheters. Indications for IR insertion included need for urgent dialysis given resource availability (36.2% [ n = 34]) and prohibitive surgical risk (26.6% [ n = 25]). Interventional radiology-inserted catheters had overall (primary and secondary) dysfunction rates of 17%. Non-embedded AL catheters had 16.1% overall dysfunction. Embedded AL-inserted PD catheters had a 24.6% overall dysfunction rate. Among all dysfunctional catheters, IR manipulation was successful in 31% ( n = 11), and surgical revision was necessary in all unsuccessful cases with either lysis of adhesions or omentopexy to establish patency. Conclusion Our PD catheter QI initiative involved tracking, outcome reporting, defining PD catheter dysfunction and PD access insertion pathway development, yielding important insights into opportunities for program improvement. Multicenter research initiatives are needed to further improve PD access dysfunction definitions and to establish the best benchmarks for these metrics.

Routine preoperative electrocardiogram (ECG) before shockwave lithotripsy (SWL) is frequently performed despite recommendations against its use in asymptomatic patients undergoing low-risk surgical procedures. This study assesses whether routine preoperative ECG before SWL is useful in patients at low risk for cardiac complications.A retrospective study of SWL at our center (2003-2013) reviewed all cardiac-related preoperative cancellations, intraoperative complications, postoperative admissions, and emergency department presentations in patients at low risk for cardiac complications. Patients received SWL with sedation and continuous five-lead ECG monitoring.Of 30,892 referrals, preoperative ECG triggered 13 (0.04%) cancelations in low-risk patients (1 with new atrial fibrillation and 12 with ischemia/previous infarction). Of these patients, 1 had a subsequent abnormal cardiac work-up and 11 underwent uncomplicated SWL without cardiac intervention (2 had unknown history). Of 27,722 treatments, 5 (0.02%) were stopped prematurely in low-risk patients because of arrhythmia (3 had normal preoperative ECG, 1 had abnormal ECG, and 1 did not complete ECG). Three patients developed an arrhythmia with sedation and 2 patients were admitted postoperatively because of cardiac complications (1 for atrial fibrillation and 1 for hypertension), of whom all had normal preoperative ECG. No patients presented to our emergency department with cardiac complications after SWL.In patients at low risk for cardiac complications, preoperative ECG triggered very few cancellations and did not predict early termination of treatment or cardiac complications after SWL. These findings suggest that in low-risk patients, routine preoperative ECG has little effect on treatment or complication rate and should be omitted.

Flexible ureteroscopy (fURS) is a one-person surgical technique, limiting trainees' ability to practice intra-operatively. Although well-suited for simulation training, few existing fURS simulators reproduce accurate, complex renal collecting system anatomies. We developed an anatomically accurate fURS simulator using 3D reconstructions of CT urograms and 3D printing technology to address this need.Patient-specific CT urograms were used to create 3D reconstructions of the renal collecting system using SlicerTM. 3D models were modified using BlenderTM. Hollow elastomer kidney models were created using an Objet 3DTM printer. To test and evaluate the new fURS simulator, 25 volunteers were recruited (5 novices, 13 residents, 7 urologists). Participants were asked to explore the model with fURS and were evaluated on their ability to deduce its 3D anatomy, their ability to navigate to prespecified calyces, and their time to task completion. Furthermore, participants were asked to compare the anatomical model to existing fURS benchtop models (Cook MedicalTM and Limb and ThingsTM) on several criteria, including internal visualization; tactile feedback; and overall functional and teaching fidelity, in a survey.We were able to create a fURS simulator that accurately replicates anatomically complex renal collecting systems. In exploring the model, we noted that unlike staff urologists, novices and residents often completely missed lower pole calyces. A survey comparison between our simulator and comparable benchtop simulators revealed consistently better ratings of our simulator on all criteria (p0.05).We were able to successfully create an anatomically accurate fURS simulator that provides a more realistic scoping experience. Preliminary testing revealed that trainees will benefit from this simulator particularly with respect to learning how to navigate challenging collecting systems.

Introduction: Obesity (body mass index [BMI] >35 kg/m2) remains a relative contraindication for kidney transplant, while patients after kidney transplantation (KTX) are predisposed to obesity. The present study aims to investigate the role of bariatric surgery in improving transplant candidacy in patients prior to KTX, as well its safety and efficacy in KTX patients postoperatively. Methods: A systematic search was conducted up to March 2020. Both comparative and non-comparative studies investigating the role of bariatric surgery before or after KTX were considered. Outcomes included change in BMI, rates of mortality and complications, and the rate of patients who underwent KTX following bariatric surgery. Pooled estimates were calculated using the random effects meta-analysis of proportions. Results: Twenty-one studies were eligible for final review; 11 studies investigated the role of bariatric surgery before KTX. The weighted mean BMI was 43.4 (5.7) kg/m2 at baseline and 33.9 (6.3) kg/m2 at 29.1 months followup. After bariatric surgery, 83% (95% confidence interval [CI] 57–99) were successfully listed for KTX and 83% (95% CI 65–97) patients subsequently received successful KTX. Ten studies investigated the role of bariatric surgery after kidney transplant. Weighted mean baseline BMI was 43.8 (2.2) kg/m2 and mean BMI at 19.5 months followup was 34.2 (6.7) kg/m2. Overall, all-cause 30-day mortality was 0.5% for both those who underwent bariatric surgery before or after receiving a KTX. The results of this study are limited by the inclusion of only non-randomized studies, limited followup, and high heterogeneity. Conclusions: Bariatric surgery may be safe and effective in reducing weight to improve KTX candidacy in patients with severe obesity and can also be used safely following KTX.

INTRODUCTION AND OBJECTIVE:In patients with end-stage renal disease, kidney transplantation improves survival. However, due to safety and increased rates of graft failure, severe obesity (BMI > 35k...

Background Simulation is becoming more important in the teaching and assessment of technical skills. The purpose of this study was to refine the use of motion analysis parameters (MAPs) to assess performance of a defined task in low-cost pediatric laparoscopic simulators of differing size. Methods 105 participants performed a defined intracorporeal suturing task in large and small pediatric laparoscopic simulators. Outcomes included MAPs — path length, extreme velocity events, and extreme acceleration events in all available degrees of freedom for novices, intermediates, and experts. ANOVA p Results In the smaller simulator, all MAPs discriminated between expertise groups in all degrees of freedom. In the larger simulator, all but one MAP discriminated between expertise groups. Experts demonstrated the greatest variability in performance between the larger and smaller simulators. Conclusion Analysis of motion in the performance of a defined intracorporeal suturing task allowed discrimination between novices, intermediates, and experts in large and small low-cost pediatric laparoscopic simulators. Further refinement in MAPs will determine their role in surgical education. Level of evidence Not applicable.

Introduction: Our aim was to explore the satisfaction, personal and professional challenges, and practice barriers among female urologists in Canada. Methods: A literature review was completed to design our survey. Trends with respect to career and personal satisfaction were identified, including academic advancement, mentorship, professional challenges, workplace discrimination, family satisfaction, and remuneration, among others. These key themes were formatted into 44 questions, translated into French, and distributed electronically as a survey to 80 female urology staff across Canada. Results: Sixty (75.0%) women completed the survey. Many had been in practice

This study analyzes instrument motion for segments of a defined intra-corporeal suturing task in a laparoscopic simulator. We describe a system providing real-time velocity and acceleration assessment in the performance of this task. Analysis of the deconstructed task segments allows targeted assessment and teaching. A traditional box trainer was fitted with a custom-built motion-tracking system. Participants were stratified into novice, intermediate and expert groups. They performed a defined intra-corporeal suturing task. Real-time data were collected in four degrees of freedom (DOFs) (Roll, Surge, Pitch, Yaw). The task was then deconstructed into four segments: loading needle/pull-through, double-throw knot, first single-throw knot, and second single-throw knot. Motion analysis parameters (MAPs) were studied for each DOF. Sixty-four participants were tested (14 novices, 19 intermediates, 31 experts). The largest difference in MAPs was seen in the ‘double-throw knot’ segment. MAPs for the ‘loading needle/pull-through’ segment revealed differences between novices and experts in Roll and Pitch DOFs only. For the ‘first single knot’ segment, similar MAP trends were noted across all DOFs, with significant differences between novices versus experts and intermediates versus experts. For the ‘second single knot’ segment, the difference in MAPs was preserved only for novices versus experts. By analyzing motion for a defined suturing task in a laparoscopic simulator, we can gain insight into the specific hand motions distinguishing experts from non-experts. Such information may allow teaching in a more focused, effective and efficient manner.

Pediatric surgical education has traditionally focused on the hard cognitive and psychomotor (technical) skills. While more and more attention is being paid to softer skills such as communication, collaboration, leadership, health advocacy, professionalism and scholarship, the bulk of curricula remain focused on the hard skills. An intricate part of education is the assessment of performance. This article reviews the current literature on the assessment of cognitive and psychomotor skills, focusing particularly on the assessment of technical skills in the realm of simulation.

Although a validated simulator exists for adult laparoscopy, there is no pediatric counterpart. The objective of this study is to develop and validate a pediatric laparoscopic surgery (PLS) simulator.A PLS simulator was developed. Participants were stratified according to level of expertise and tested on the fundamentals of laparoscopic surgery (FLS) and PLS simulators. A subsequent group was tested exclusively on the PLS simulator.The PLS intracorporeal suturing score was lower than its adult counterpart (P = .02). The PLS pattern-cutting score was higher than in the FLS simulator (P.001). If the latter was eliminated from the calculation, the revised total FLS score was significantly better than the revised PLS score. When all participants were combined, total PLS scores as well as performance on 3 of 5 tasks allowed differentiation between novice, intermediate, and expert.The PLS simulator was able to discriminate between the novice, intermediate, and expert using the total PLS score and the performance on 3 of the 5 tasks, thus providing evidence for construct validity. The other 2 tasks will require formal modification or a change in the scoring metrics to establish their independent construct validity.

Introduccion. El programa “Fundamentos de Cirugia Laparoscopica” es un modulo educativo desarrollado por la Society of American Gastrointestinal Endoscopic Surgeons , que incluye el desarrollo de habilidades practicas y conocimientos teoricos en cirugia laparoscopica. Su mision principal es brindar a los residentes de las areas quirurgicas, y a los cirujanos en general, una herramienta adicional en su formacion, para aprender los fundamentos y el conocimiento teorico necesario para la practica de la cirugia laparoscopica, lo que garantizara un mejor desempeno en las salas de cirugia y, por ende, mayor seguridad para los pacientes. Objetivo. Evaluar la efectividad de la telesimulacion para ensenar el componente practico del programa “Fundamentos de Cirugia Laparoscopica” en Colombia. Materiales y metodos. Veinte participantes (10 cirujanos generales y 10 residentes de cirugia general) de dos ciudades de Colombia, participaron en ocho sesiones (una semanal) de entrenamiento en “Fundamentos de Cirugia Laparoscopica” mediante telesimulacion. Se les hizo un examen practico antes de las telesimulaciones, y un examen teorico y practico, al final de las ocho sesiones. Resultados. Utilizando parametros numericos definidos por la Society of American Gastrointestinal Endoscopic Surgeons , se encontro diferencias significativas el examen previo y el posterior. El 100 % de los participantes aprobaron el componente practico del programa. Conclusiones. Este estudio demuestra la efectividad de la telesimulacion para mejorar las habilidades laparoscopicas de participantes sin conocimiento previo del programa “Fundamentos de Cirugia Laparoscopica”, lo que garantizo obtener el puntaje necesario para aprobar la seccion practica del programa. doi: http://dx.doi.org/ 10.7705/biomedica.v33i1.1425

Endothelial cells are known to respond to hemodynamic forces. Their phenotype has been suggested to differ between atheroprone and atheroprotective regions of the vasculature, which are characterized by the local hemodynamic environment. Once an atherosclerotic plaque has formed in a vessel, the obstruction creates complex spatial gradients in wall shear stress. Endothelial cell response to wall shear stress may be linked to the stability of coronary plaques. Unfortunately, in vitro studies of the endothelial cell involvement in plaque stability have been limited by unrealistic and simplified geometries, which cannot reproduce accurately the hemodynamics created by a coronary stenosis. Hence, in an attempt to better replicate the spatial wall shear stress gradient patterns in an atherosclerotic region, a three dimensional asymmetric stenosis model was created. Human abdominal aortic endothelial cells were exposed to steady flow (Re=50, 100, and 200 and τ=4.5 dyn/cm2, 9 dyn/cm2, and 18 dyn/cm2) in idealized 50% asymmetric stenosis and straight/tubular in vitro models. Local morphological changes that occur due to magnitude, duration, and spatial gradients were quantified to identify differences in cell response. In the one dimensional flow regions, where flow is fully developed and uniform wall shear stress is observed, cells aligned in flow direction and had a spindlelike shape when compared with static controls. Morphological changes were progressive and a function of time and magnitude in these regions. Cells were more randomly oriented and had a more cobblestone shape in regions of spatial wall shear stress gradients. These regions were present, both proximal and distal, at the stenosis and on the wall opposite to the stenosis. The response of endothelial cells to spatial wall shear stress gradients both in regions of acceleration and deceleration and without flow recirculation has not been previously reported. This study shows the dependence of endothelial cell morphology on spatial wall shear stress gradients and demonstrates that care must be taken to account for altered phenotype due to geometric features. These results may help explain plaque stability, as cells in shoulder regions near an atherosclerotic plaque had a cobblestone morphology indicating that they may be more permeable to subendothelial transport and express prothrombotic factors, which would increase the risk of atherothrombosis.

The response of the vascular endothelium to wall shear stress plays a central role in the development and progression of atherosclerosis. Current studies have investigated endothelial response using idealized in vitro flow chambers. Such cell culture models are unable to accurately replicate the complex in vivo wall shear stress patterns arising from anatomical geometries. To better understand this implication, we have created both simplified/tubular and anatomically realistic in vitro endothelial flow models of the human right coronary artery. A post-mortem vascular cast of the human left ventricular outflow tract was used to create geometrically accurate silicone elastomer models. Straight, tubular models were created using a custom made mold. Following the culture of human abdominal aortic endothelial cells within the inner lumen, cells were exposed to steady flow (Re = 233) for varying time periods. The resulting cell morphology was analyzed in terms of shape index and angle of orientation relative to the flow direction. In both models a progressive elongation and alignment of the endothelium in the flow direction was observed following 8, 12, and 24 hours. This change, however, was significantly less pronounced in the anatomical model (as observed from morphological variations indicative of localized flow features). Differences were also observed between the inner and outer walls at the disease-prone proximal region. Since morphological adaptation is a visual indication of endothelial shear stress activation, the use of anatomical models in endothelial genetic and biochemical studies may offer better insight into the disease process.

Endothelial cell dysfunction in response to hemodynamic forces is believed to be a cause of focal atherosclerosis. Flow in stenotic vessels creates complex spatial wall shear stress (WSS) gradients which may alter endothelial cell function and promote adhesion of inflammatory cells. In vitro studies have generally used unrealistic geometries, which cannot reproduce the complexity of physiological hemodynamics. We have developed a three dimensional asymmetric stenosis cell culture model to better study the interaction of endothelial cells with blood components. Human abdominal aortic endothelial cells (ECs) were exposed to steady physiological flows in our models. The adhesive properties of human promyelocytic cells (NB4) following exposure to all-trans-retinoic acid (ATRA) on ECs, were studied. Cells subjected to one dimensional flow aligned in flow direction and had a spindle-like shape when compared to static controls. EC morphology differed in the spatial WSS gradient regions, being randomly oriented and of cobblestone shape. Tumor necrosis factor α stimulation (TNF-α) increased significantly the expression of intercellular adhesion molecule (ICAM-1) and vascular cell adhesion molecule (VCAM-1) on ECs as observed by confocal microscopy and western blots. These cell adhesion molecules are known to be involved in inflammation and upregulated under the control of transcription factor nuclear factor κB (NF-κB). Under static conditions, NB4 cells adhered to a greater extent than under flow, with decreased adhesion observed with increasing flowrate. Regionally, cells under flow adhered more in the low wall shear stress recirculation region distal to the stenosis than in the one dimensional flow inlet region. At the proximal shoulder regions, greater adhesion was noticed although this was not significant. This suggests an important shear mediated role of neutrophil-endothelial interactions in the progression of atherosclerosis. Moreover, the regional response to complex hemodynamics may play an important role in plaque stability.

Upon clinical analysis, regions such as curvatures and bifurcations have been characterized as high prone regions where atherosclerotic plaques were more likely to occur. Biological studies have linked this phenomenon to the localized response of the endothelial cells to mechanical blood flow forces such as fluid shear stress. Present common in vitro flow cell culture models such as parallel-plate flow chambers and cone and plate viscometers used to study endothelial cell response depict a simplified geometry and thus, unrealistic in vivo conditions. The aim of this project was to develop a more realistic in vitro cell culture model by using an anatomically correct right coronary artery model and a more physiologic flow environment for dynamic endothelial cell culture experiments.Copyright © 2007 by ASME

Endothelial cell (EC) dysfunction has been linked to atherosclerosis through their response to hemodynamic forces. Flow in stenotic vessels creates complex spatial gradients in wall shear stress. In vitro studies examining the effect of shear stress on endothelial cells have used unrealistic and simplified models, which cannot reproduce physiological conditions. The objective of this study was to expose endothelial cells to the complex shear shear pattern created by an asymmetric stenosis. Endothelial cells were grown and exposed for different times to physiological steady flow in straight dynamic controls and in idealized asymmetric stenosis models. Cells subjected to 1D flow aligned with flow direction and had a spindle-like shape when compared to static controls. Endothelial cell morphology was noticeable different in the regions with a spatial gradient in wall shear stress, being more randomly oriented and of cobblestone shape. This occurred despite the presence of an increased magnitude in shear stress. No other study to date has described this morphology in the presence of a positive wall shear stress gradient or gradient of significant shear magnitude. This technique provides a more realistic model to study endothelial cell response to spatial and temporal shear stress gradients that are present in vivo and is an important advancement towards a better understanding of the mechanisms involved in coronary artery disease.