Developing an Ex Vivo Pig Model for Teaching Ultrasound and Fluoroscopy-Guided Percutaneous Renal Access.

Introduction: Establishing percutaneous renal access is the key initial step to percutaneous nephrolithotomy; however, learning the technique during surgery for trainees is complicated by the number of approaches used to gain access, limited completion time during a breath hold. and attempt to minimize the number of passes through a kidney. There are many training models for percutaneous access commercially available all with their respective limitations. Our objective was to develop a low-cost, high-fidelity percutaneous access training model that addresses existing limitations and can be used with both ultrasound and fluoroscopy guidance. Methods: After a formal ethics exemption was attained, pig cadavers were harvested for flank, kidneys, and ureters. These were incorporated into a composite porcine tissue mould, created within a gelatin matrix. In the initial assessment, establishing percutaneous access under both ultrasound and fluoroscopy guidance was tested to refine usability. Once acceptable, its use during a training course was evaluated to assess impressions for use with ultrasound. Results: We were able to create a $45USD biodegradable model, which can facilitate percutaneous access using: fluoroscopy with intrarenal contrast; fluoroscopy with endoscopic guidance; and fluoro-less that is, ultrasound only. A cohort of 12 Canadian Postgraduate Year-3 residents who used the model for ultrasound access agreed that the model simulated a comparable tactile experience (58.33%) and anatomy (75%) to humans. Furthermore, majority of the residents agreed that model was easy to use with ultrasound guidance (91.67%), was a beneficial experience for their learning and future practice (83.33%) and if available would use to complement their intraoperative training (83.33%). Conclusion: We were able to develop a low-cost, preliminarily tested ex vivo pig model for percutaneous access compatible with multiple imaging modalities. We will continue refining our model and seek to understand its benefits when teaching percutaneous access to varying levels of learners.

Three-dimensionally printed non-biological simulator for percutaneous nephrolithotomy training.

Objective: We sought to improve the educational and pre-operative training on various stages of percutaneous nephrolithotomy (PCNL) under fluoroscopic and ultrasound guidance. We developed a three-dimensional (3D) printed simulator (3D-printed PCNL model) for urological trainees.Methods: 40 s year urology residents were randomly assigned into two groups, completing PCNL surgical steps on a URO Mentor™ surgical simulator (Group A) or on our new 3D-printed PCNL model (Group B). Following the training, both groups completed a standardized questionnaire (Likert scale from 0 to 10) which we used to asses the learning curve associated with PCNL training.Results: The mean score of Group A was 65.2/80 while Group B was 76.1/80. Mann-Whitney U-test showed no significant difference between the groups (U = 16, p < 0.05).Conclusion: The 3D-printed PCNL model developed is a novel and highly effective tool that can facilitate enhanced endourological education and personalized pre-operative planning for urolithiasis cases. According to the criteria tested, residents who used our 3D-printed PCNL models performed better under all metrics.

Retrograde nephrostomy access for percutaneous nephrolithotomy: a simple and safe technique.

This study aimed at illustrating our experience with the retrograde nephrostomy access technique for percutaneous nephrolithotomy (PCNL).This retrospective study was conducted between June 1997 and September 2018 for 648 patients who underwent PCNL with retrograde nephrostomy access. Included in the study were the patient demographic, operative time, site of the access, fluoroscopic exposure time, stone clearance rate, additional procedures and complications. A total of 648 patients aged between 25 and 70 years had renal stones and were included in this study. Retrograde nephrostomy access was achieved through the upper calyx in 252 patients (38.9%), middle calyx in 348 patients (53.7%) and lower calyx in 48 patients (7.4%). Among those patients, 108 (16.7%) required supracostal access. The average time for the retrograde access and PCNL was 14.4 min and 40 min, respectively. The average fluoroscopic exposure time for the retrograde access was 3.2 min. There were 12 failures (1.9%) as a result of severe hydronephrosis. Complete stone clearance was achieved in 91.8%. Small stone fragments (4 mm or less) were detected in 7.4%. Median hospital stay was 3.5 days (range 3-7). Complications occurred in 39 patients (6%). Eight patients (1.2%) developed significant postoperative hemorrhage that was controlled by transfusion and angioembolization. There were no recorded cases of colonic injuries, pneumothorax or hemothorax, demonstrating that the retrograde access technique is safe and reliable. It provides control over both ends of the wire eliminating the risk of accidental wire displacement. Radiation exposure is minimal. There are low failure and complication rates.

Thiel-embalmed cadavers as a novel training model for ultrasound-guided supine endoscopic combined intrarenal surgery.

OBJECTIVE: To evaluate Thiel-embalmed cadavers (TEC) as a training model for percutaneous nephrolithotomy (PCNL), more specifically for ultrasound (US)-guided supine endoscopic combined intrarenal surgery (ECIRS). SUBJECTS AND METHODS: Thirteen urologists (nine experienced endourologists, four fellows/residents) performed an US-guided supine ECIRS procedure on a TEC. The model was evaluated by way of a questionnaire (5-point Likert scale). Descriptive statistical analysis was performed and results were graphically presented using divergent bar graphs. RESULTS: US images were appreciated as lifelike in all aspects. Although distention of the collecting system was not ideal in one out of three TEC, US visualisation of the distended calyces during puncture was good. Skin penetration was more difficult and less realistic in TEC, while kidney puncture and dilatation were deemed very realistic. Ureteric and collecting system anatomy and consistency were similar to real life, although the mucosa appeared paler. US needle guidance was perceived as excellent. Overall, needle puncture assessment was realistic and useful as a training tool. Overall quality and satisfaction of TEC in US-guided supine ECIRS was good to excellent and comparable to a real-life procedure. Overall appropriateness of the TEC model was considered excellent for both initial and advanced supine PCNL training. CONCLUSION: Despite the minor drawbacks of tough skin and non-ideal collecting system dilatation during ureteroscopy, the TEC model was considered good to excellent as a training model for US-guided PCNL, in particular, US-guided needle puncture of the kidney during supine ECIRS.

[Using of a dismountable 3D-model of the collecting system with color segmentation to improve the learning curve of residents].

AIM: to determine the efficiency of using a non-biological dismountable 3D-model of the collecting system with color segmentation for better understanding of its anatomy by residents and to determine the optimal tactics of percutaneous nephrolithotomy (PNL). MATERIALS AND METHODS: 3D-models of the collecting system were developed based on CT data of 5 patients with staghorn stones, for whom PNL was planned. CT images were obtained in the Dicom format. RadiAnt DICOM Viewer was used for delineation and segmentation of the collecting system with 3D visualization. Using slicer 4.8.1 software, virtual models were processed to convert DICOM files to STL format. Then, virtual color extraction of each group of calyxes was performed for convenient disassembling and intraluminal study of the anatomy of the collecting system. The final stage included the printing of each area by the method of layer-by-layer deposition using a 3D printer Picaso designer X. To assess the efficiency of the dismountable 3D-model that simulates a certain collecting system, a questionnaire was used. It allowed to evaluate the understanding of the anatomy of the collecting system by residents, as well as the ability to determine the optimal calyx for PNL by comparing the answers with the result of a survey of practicing urologists who had performed more than 50 cases. RESULTS: After studying 3D-models by residents, determination of the number of calyxes in each group was not statistically significantly different from those for practicing urologists who used CT images. The choice of the calyx for primary puncture was not different between groups. However, residents chose the calyx for additional access worse (p=0.009). CONCLUSION: The dismountable 3D-model of the collecting system is promising for training of residents and planning PNL. Studying the anatomy of a single group of calyxes as well as the entire collecting system allows to choose the optimal calyx for percutaneous puncture during PNL.

Pilot Assessment of Immersive Virtual Reality Renal Models as an Educational and Preoperative Planning Tool for Percutaneous Nephrolithotomy.

BACKGROUND: Percutaneous nephrolithotomy (PCNL) requires the urologist to have detailed knowledge of the stone and its relationship with the renal anatomy. Immersive virtual reality (iVR) provides patient-specific three-dimensional models that might be beneficial in this regard. Our objective is to present the initial experience with iVR in surgeon planning and patient preoperative education for PCNL. MATERIALS AND METHODS: From 2017 to 2018 four surgeons, each of whom had varying expertise in PCNL, used iVR models to acquaint themselves with the renal anatomy before PCNL among 25 patients. iVR renderings were also viewed by patients using the same head-mounted Oculus rift display. Surgeons rated their understanding of the anatomy with CT alone and then after CT+iVR; patients also recorded their experience with iVR. To assess the impact on outcomes, the 25 iVR study patients were compared with 25 retrospective matched-paired non-iVR patients. Student's t-test was used to analyze collected data. RESULTS: iVR improved surgeons' understanding of the optimal calix of entry and the stone's location, size, and orientation (p < 0.01). iVR altered the surgical approach in 10 (40%) cases. Patients strongly agreed that iVR improved their understanding of their stone disease and reduced their preoperative anxiety. In the retrospective matched-paired analysis, the iVR group had a statistically significant decrease in fluoroscopy time and blood loss as well as a trend toward fewer nephrostomy tracts and a higher stone-free rate. CONCLUSIONS: iVR improved urologists' understanding of the renal anatomy and altered the operative approach in 40% of cases. In addition, iVR improved patient comprehension of their surgery. Clinically, iVR had benefits with regard to decreased fluoroscopy time and less blood loss along with a trend toward fewer access tracts and higher stone-free rates.

Contemporary practice patterns in the treatment of pediatric stone disease.

INTRODUCTION: To compare endourology versus pediatric urology exposure to pediatric stone cases during fellowship, comfortability in treating pediatric stone cases, and access to pediatric surgical equipment. MATERIALS AND METHODS: A survey was distributed to all pediatric urology fellowship programs and the Endourological Society. Age was stratified into < 12 months old, 12 months-4 years, 5-12 years, and 13-18 years. Exposure and comfortability performing extracorporeal shock wave lithotripsy (SWL), ureteroscopy (URS) and percutaneous nephrolithotomy (PCNL) were assessed across age groups. Exposure was assessed as 'yes/no' and comfortability was scaled from 1-5 ('would not do' to 'very comfortable'). RESULTS: Seventy-two surveys met inclusion criteria, with 23 (31.9%) from pediatric urologists and 49 (68.1%) by endourologists. During fellowship, pediatric urologists had more exposure to SWL in toddlers (p = 0.03) and school age children (p = 0.045), URS in toddlers (p = 0.012) and school age children (p = 0.002), and PCNL in infants (p = 0.031) and school age children (p = 0.025) compared to endourologists. Pediatric urologists were significantly more comfortable performing SWL in toddlers (p = 0.04), URS in toddlers (p = 0.04) and school age children (p = 0.04), and PCNL in school age children (p = 0.02) compared to endourologists. Endourologists were significantly more uncomfortable than pediatric urologists in performing URS in toddlers (p = 0.03) and PCNL in infants (p = 0.04) and school age children (p = 0.03). There were no differences in availability of pediatric equipment. CONCLUSIONS: Pediatric urologists, have significantly more exposure than endourologists during fellowship and are more comfortable performing surgical treatment for urolithiasis in most pediatric ages. Endourology fellowships may benefit from greater exposure to pediatric patients with stones.

Learning Curves in Urolithiasis Surgery: A Systematic Review.

BACKGROUND AND AIMS: Procedures for urolithiasis are a core part of the development for the urologist in training. Understanding the learning curve of the procedures is important, allowing for planning in the training and assessment of trainees. The aim of this study was to systematically review the literature pertaining to learning curves in urolithiasis surgery. MATERIALS AND METHODS: The review was registered on the PROSPERO database and conducted in keeping with the Preferred Reporting Items for Systematic reviews and Meta-Analysis statement. Embase, MEDLINE, and PsycINFO were systematically searched from inception to January 2018, with a reference review conducted. All empirical studies on learning curves in urolithiasis surgery were included irrespective of procedure. Articles describing pediatric surgery, nontechnical skills in surgery, or those not written in English were excluded. RESULTS: Of 390 articles identified from screening, a final 18 studies were included. Fourteen studies identified the learning curve in percutaneous nephrolithotomy. These studies identified a learning curve of between 30 and 60 cases for both operative time (OT) and complication rates. Four articles focused on flexible ureteroscopy (FURS); the learning curve for FURS has been outlined as 60 cases for OT and 56 cases for fragmentation efficacy. CONCLUSIONS: The complexities of determining learning curves are extensive; studies use different parameters to measure outcomes and observe skill acquisition rates of surgeons with differing prior experience. Evidence in this article can guide trainee urologists with regard to the expected rate of progress. Multi-operator multicenter research utilizing standard outcome measures should be conducted to establish definitive learning curves.

Differences in the percutaneous nephrolithotomy practice patterns among Latin American urologists with and without endourology training

ABSTRACT Purpose: Although the worldwide percutaneous nephrolithotomy (PCNL) practice pat- terns determined via a survey sent to members of the Endourological Society have been published, differences in PCNL practice patterns among Latin American urologists based on endourological or lithiasis training have not been published. To determine the PCNL practice patterns among Latin American urologists with and without training in endourology. Materials and Methods: The SurveyMonkey® web platform was used to develop a 27-item survey on PCNL for the treatment of renal stones, and the survey was sent via e- -mail and other electronic media to 2000 urologists from 15 Latin American countries. Endourology-trained (group 1) and nontrained urologists (group 2) were analyzed. The group results were compared using the chi-squared and Fisher's exact tests. SPSS version 20 for Windows was used for all analyses. Results: A total of 331 urologists responded to the survey (rate of 16.55%): 221 (66.7%) in group 1 and 110 (33.2%) in group 2). In groups 1 and 2, 91.9% and 63.2% performed PCNL, respectively: 85.1% and 58.5% used preoperative tomography, respectively; 12.7% and 4.7% used preoperative nephrolitometry nomograms, respectively: 45.2% and 32.1% used endoscopic combined intrarenal surgery, respectively: 68.3% and 38.7% used mul- tiple percutaneous tract realization, respectively: and 19.9% and 5.7% used minimally invasive PCNL, respectively (all p=0.0005). Conclusions: Statistically significant differences were observed in PCNL practice patterns of Latin American urologists with and without training in endourology. Specific training in endourology significantly influence the practice patterns of Latin American urologists.

Differences in the percutaneous nephrolithotomy practice patterns among Latin American urologists with and without endourology training.

PURPOSE: Although the worldwide percutaneous nephrolithotomy (PCNL) practice patterns determined via a survey sent to members of the Endourological Society have been published, differences in PCNL practice patterns among Latin American urologists based on endourological or lithiasis training have not been published. To determine the PCNL practice patterns among Latin American urologists with and without training in endourology. MATERIALS AND METHODS: The SurveyMonkey® web platform was used to develop a 27- item survey on PCNL for the treatment of renal stones, and the survey was sent via e-mail and other electronic media to 2000 urologists from 15 Latin American countries. Endourology-trained (group 1) and nontrained urologists (group 2) were analyzed. The group results were compared using the chi-squared and Fisher's exact tests. SPSS version 20 for Windows was used for all analyses. RESULTS: A total of 331 urologists responded to the survey (rate of 16.55%): 221 (66.7%) in group 1 and 110 (33.2%) in group 2). In groups 1 and 2, 91.9% and 63.2% performed PCNL, respectively; 85.1% and 58.5% used preoperative tomography, respectively; 12.7% and 4.7% used preoperative nephrolitometry nomograms, respectively; 45.2% and 32.1% used endoscopic combined intrarenal surgery, respectively; 68.3% and 38.7% used multiple percutaneous tract realization, respectively; and 19.9% and 5.7% used minimally invasive PCNL, respectively (all p=0.0005). CONCLUSIONS: Statistically significant differences were observed in PCNL practice patterns of Latin American urologists with and without training in endourology. Specific training in endourology significantly influence the practice patterns of Latin American urologists.

Incorporation of the fluoroless C-Arm Trainer at the American Urological Association hands on training percutaneous renal access.

OBJECTIVES: To assess for usefulness and validity evidence for incorporating the C-Arm Trainer (CAT) simulator into the annual AUA hands on course for training percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: The course started with a didactic session followed by four stations for training the "bull's eye" technique using the CAT simulator. Each station included a pre-test, 30-min practice on the simulator, and post-test. All participants were assessed using a 4-item checklist. All participants were asked to fill in a qualitative self-assessment questionnaire after the pre- and the post-test, and respond to a course evaluation questionnaire and post-course survey. RESULTS: A total of 38 physicians, who attended the hands on course, voluntarily participated in the study. Only 21.1% had previous practice on PCNL simulators. Compared with the results of the checklist total score and the qualitative self-assessment questionnaire scores after the pre-test, there was significant improvement in the checklist total score (p < 0.001), temporal demands (p = 0.003), situational stress (p = 0.003, and performance (0.003) after the post-test. A total of 14 (36%) participants responded to the course evaluation questionnaire, 50% evaluated the course as excellent, 28.6% as very good, and 21.4% as good. Unfortunately, only five (13%) participants responded to the post-course survey, 4/5 implemented the new competencies and knowledge into their practice, and 3/5 have attempted to obtain fluoroscopic guided PCA without assistance. CONCLUSION: The CAT simulator was considered useful for training the percutaneous renal access procedure. There was significant improvement in the qualitative and quantitative assessment parameters after the post-test compared with the pre-test.

Validation of a Full-Immersion Simulation Platform for Percutaneous Nephrolithotomy Using Three-Dimensional Printing Technology.

INTRODUCTION AND OBJECTIVES: The restriction of resident hours with an increasing focus on patient safety and a reduced caseload has impacted surgical training. A complex and complication prone procedure such as percutaneous nephrolithotomy (PCNL) with a steep learning curve may create an unsafe environment for hands-on resident training. In this study, we validate a high fidelity, inanimate PCNL model within a full-immersion simulation environment. METHODS: Anatomically correct models of the human pelvicaliceal system, kidney, and relevant adjacent structures were created using polyvinyl alcohol hydrogels and three-dimensional-printed injection molds. All steps of a PCNL were simulated including percutaneous renal access, nephroscopy, and lithotripsy. Five experts (>100 caseload) and 10 novices (<20 caseload) from both urology (full procedure) and interventional radiology (access only) departments completed the simulation. Face and content validity were calculated using model ratings for similarity to the real procedure and usefulness as a training tool. Differences in performance among groups with various levels of experience using clinically relevant procedural metrics were used to calculate construct validity. RESULTS: The model was determined to have an excellent face and content validity with an average score of 4.5/5.0 and 4.6/5.0, respectively. There were significant differences between novice and expert operative metrics including mean fluoroscopy time, the number of percutaneous access attempts, and number of times the needle was repositioned. Experts achieved better stone clearance with fewer procedural complications. CONCLUSIONS: We demonstrated the face, content, and construct validity of an inanimate, full task trainer for PCNL. Construct validity between experts and novices was demonstrated using incorporated procedural metrics, which permitted the accurate assessment of performance. While hands-on training under supervision remains an integral part of any residency, this full-immersion simulation provides a comprehensive tool for surgical skills development and evaluation before hands-on exposure.

Trainee-Associated Factors and Proficiency at Percutaneous Nephrolithotomy.

Percutaneous nephrolithotomy (PNL) is a complicated procedure for urology trainees. This study was designed to investigate the effect of trainees' ages and previous experience, as well as the number of operated cases, on proficiency at PNL by using patient outcomes. A cross sectional observational study was designed during a five-year period. Trainees in PNL fellowship programs were included. At the end of the program, the trainees' performance in PNL was assessed regarding five competencies and scored 1-5. If the overall score was 4 or above, the trainee was considered as proficient. The trainees' age at the beginning of the program and the years passed from their residency graduation were asked and recorded. Also, the number of PNL cases operated by each trainee was obtained via their logbooks. The age, years passed from graduation, and number of operated cases were compared between two groups of proficient and non-proficient trainees. Univariate and multivariate binary logistic regression analysis was applied to estimate the effect of aforementioned variables on the occurrence of the proficiency. Forty-two trainees were included in the study. The mean and standard deviation for the overall score were 3.40 (out of 5) and 0.67, respectively. Eleven trainees (26.2%) recognized as proficient in performing PNL. Univariate regression analysis indicated that each of three variables (age, years passed from graduation and number of operated cases) had statistically significant effect on proficiency. However, the multivariate regression analysis revealed that just the number of cases had significant effect on achieving proficiency. Although it might be assumed that trainees' age negatively correlates with their scores, in fact, it is their amount of practice that makes a difference. A certain number of cases is required to be operated by a trainee in order to reach the desired competency in PNL.

Implementation of minimally invasive percutaneous nephrolithotomy (MIP): comparison of the initial learning curve with the later on clinical routine in a tertiary centre.

OBJECTIVE: We report on the comparison of clinical results of the early phase of implementation of minimally invasive PNL (MIP) in a mentor-based approach with the later on clinical routine in a tertiary centre. PATIENTS AND METHODS: From January 2010 until January 2015 MIP was performed in 190 patients. Stone and patient characteristics were recorded in prospective manner. Perioperative complications were recorded within the Clavien-Classification. The first 120 consecutive patients undergoing MIP were evaluated and divided into three groups of 40 patients each. Mentor-based introduction of MIP was done within the first 40 patients (group A). Further patients were treated on routine clinical practice basis (group B and C). Treatment outcome was compared within the three groups. RESULTS: The groups did not significantly differ with regard to patient characteristics, operation time and decline in haemoglobin. In the mentor-based series mean stone size was 21.7 ± 12.6 vs. 15.6 ± 7.9 and 16.1 ± 8.4 mm in group B and C (p = 0.033). Primary stone-free rates were 65, 87.5 and 87.5% for the three groups (p = 0.015). Stone-free rate was higher in smaller and simple stones. Overall, complication rate was 41.7% including 36.7% Clavien grade I and II complications. CONCLUSIONS: MIP can be implemented safe and effectively with mentor-based approach. MIP has a high safety profile, which allows high safety and efficacy of MIP at the time of implementation.

Outcome from 5-year live surgical demonstrations in urinary stone treatment: are outcomes compromised?

PURPOSE: To compare intra- and post-operative outcomes of endourological live surgical demonstrations (LSDs) and routine surgical practice (RSP) for urinary stones. METHODS: Consecutive ureterorenoscopic (URS) and percutaneous (PNL) urinary stone procedures over a 5-year period were reviewed. Procedures were divided into LSDs and RSP. Differences between the groups were separately analysed for URS and PNL. Primary outcomes included intra- and post-operative complication rates and grades. Secondary outcomes were operation time, length of hospital stay, stone-free rate, and retreatment rate. Pearson's Chi-square analysis, Mann-Whitney U test, and logistic and linear regression were used to compare outcomes between LSDs and RSP. RESULTS: During the study period, we performed 666 URSs and 182 PNLs, and 151 of these procedures were LSDs. Among URSs, the overall intra-operative complication rate was 3.2% for LSDs and 2.5% for RSP (p = 0.72) and the overall post-operative complication rate was 13.7% for LSDs and 8.8% for RSP (p = 0.13). Among PNLs, the overall intra-operative complication rate was 8.9% for LSDs and 5.6% for RSP (p = 0.52) and the overall post-operative complication rate was 28.6% for LSDs and 34.9% for RSP (p = 0.40). For both URSs and PNLs, no statistically significant differences in complication grade scores were observed between LSDs and RSP. Operation time was significantly longer for LSD-URS group, but there was no difference between the PNL groups. There were no significant differences in length of hospital stay and stone-free rate. The retreatment rate was higher in the LSD-URS group compared with RSP-URS group but similar between the PNL groups. Multiple logistic regression analyses, adjusting for confounders, revealed no association between LSD and more or less favourable outcomes as compared to RSP. CONCLUSION: Live surgical demonstrations do not seem to compromise patients' safety and outcomes when performed by specialised endourologists.

Percutaneous nephrolithotomy: technique.

Percutaneous nephrolithotomy (PCNL) is considered to be the first line of treatment for large renal stones. Though PCNL comes with higher morbidity, its efficacy is unbeaten by other minimally invasive modalities. However, potential complications, such as bleeding, occur. Improved skills and modifications of the procedure may reduce the probability of adverse outcomes. This article discusses the current trends and standards in PCNL technique with special focus on all important steps as positioning, access, instruments, dilation, disintegration, and exit, including outcomes, complication management, and training modalities.