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Objectives: The super-pulsed thulium fiber laser (SP TFL) is a new alternative to high-power holmium laser for intracorporeal lithotripsy. The SP TFL has shown advantages in dusting regimes, but benefits in fragmentation regimes are less understood. The second-generation SP TFL introduces an advanced fragmentation pulse (AFP) sequence to maximize SP TFL's efficiency in fragmentation. This study evaluates safety and efficacy of the SP TFL fragmentation mode in ureteroscopy (URS) and mini percutaneous nephrolithotomy (mini-PCNL). Materials and Methods: The study was conducted in two phases. Safety of a new AFP was compared ex vivo to standard SP TFL fragmentation settings by measuring the dimensions of wounds created in porcine kidney after laser exposure for 0.5, 1.0, and 2.0 s. The resulting wounds were evaluated histologically using nitro blue tetrazolium chloride (NBTC) stain. In the clinical phase, the second-generation SP TFL was used to fragment and extract ureteral and renal stones in 40 patients using ureteroscopic and percutaneous approaches. The stone size, volume, density, laser-on-time, and total energy were recorded for each patient. In addition, the chemical composition, ablation rate, and ablation efficiency were assessed for each stone treatment. Results: The ex vivo mucosa damage profiles caused by AFP were similar to those caused by regular pulses. In clinical phase, the median volume and density for ureteral stones were 0.4 cm3 and 1029 Hounsfield units (HU), for renal stones 1.3 cm3 and 1113 HU, respectively. Different stone types were crushed into fragments suitable for extraction. The mean AFP energy was 3 J and the average power for ureteral stones was 10.5 W, whereas for renal stones it was 28.5 J and 31 W, respectively. The overall complication rate was low in both groups. Conclusion: ST PFL with AFP capability facilitates effective fragmentation of ureteral and renal stones of any composition during URS and mini-PCNL with minimal complication rates. [ABSTRACT FROM AUTHOR]

Objective: National guidelines recommend periprocedural antibiotics before percutaneous nephrolithotomy (PCNL), yet it is not clear which is superior. We conducted a randomized trial to compare two guideline-recommended antibiotics: ciprofloxacin (cipro) vs cefazolin, on PCNL outcomes, focusing on the development of systemic inflammatory response syndrome (SIRS) criteria. Methods: Adult patients who were not considered high risk for surgical or infectious complications and undergoing PCNL were randomized to receive either cipro or cefazolin perioperatively. All had negative preoperative urine cultures. Demographic and perioperative data were collected, including SIRS criteria, intraoperative urine culture, duration of hospitalization, and need for intensive care. SIRS is defined by ≥2 of the following: body temperature <96.8°F or >100.4°F, heart rate >90 bpm, respiratory rate >20 per minute, and white blood cell count <4000 or >12,000 cells/mm3. Results: One hundred forty-seven patients were enrolled and randomized (79 cefazolin and 68 cipro). All preoperative characteristics were similar (p > 0.05), except for mean age, which was higher in the cipro group (64 vs 57 years, p = 0.03). Intra- and postoperative findings were similar, with no difference between groups (p > 0.05), except a longer mean hospital stay in the cefazolin group (2 hours longer, p = 0.02). There was no difference between SIRS episodes in both univariate and multivariate analyses. Conclusions: Despite the relatively broader coverage for urinary tract pathogens with ciprofloxacin, this prospective randomized trial did not show superiority over cefazolin. Our findings therefore support two appropriate options for perioperative antibiotic prophylaxis in patients undergoing PCNL who are nonhigh risk for infectious complications. [ABSTRACT FROM AUTHOR]

Introduction and Objective: The study's primary objective was to compare the laser efficiency and clinical outcomes of two widely used systems, the holmium MOSES laser and the thulium fiber laser (TFL), in managing kidney stones. The secondary outcomes were to evaluate the impact of stone composition on laser efficacy. Methods: We conducted a retrospective review of patients who underwent flexible ureteroscopy (f-URS) for solitary renal calculi between December 2020 and August 2022 at our institution and had a 3-month postoperative CT scan. Patient demographics and stone parameters were recorded, including stone site, size, volume, and density. Intraoperative data were collected and analyzed, including total operative time, ureteroscopy time, lasing time, technique, total energy delivered, and stone composition. All patients underwent a CT scan at 3 months follow-up. We recorded the presence of residual stones and the percentage of stone volume reduction. Ablation efficiency was calculated by dividing the energy utilized (J) by the stone volume (mm3). The ablation speed was calculated by dividing the stone volume (mm3) by the lasing time (seconds). Patients with a stone size <4 mm were deemed stone-free. Results: The MOSES and TFL groups comprised 62 and 49 patients, respectively. There were no significant differences between groups for baseline patient demographics or stone characteristics. The two modalities had comparable total energy, laser time, efficacy, and ablation speeds. No differences were detected in stone-free rates or complications between both groups. When dealing with calcium phosphate stones, we observed that the lasing time was significantly shorter with MOSES than TFL (7.95 vs 10.85 minutes, respectively [p = 0.01]). Conclusions: MOSES and TFL laser systems had comparable efficacy for lithotripsy of renal calculi during f-URS; however, calcium phosphate stones had a longer lasing time with TFL. REB Number: 100210. [ABSTRACT FROM AUTHOR]

Introduction: American Urological Association (AUA) guidelines recommend percutaneous nephrolithotomy (PCNL) for total stone burden greater than 20 mm, yet it is unclear if the number of stones affects adherence to this guideline. We aim to assess the impact of stone multiplicity on the choice of ureteroscopy (URS) vs PCNL as a first-line therapy for patients with high burden (>20 mm), and examine whether the AUA guideline-discordant care impacts patient outcomes. Materials and Methods: Data were collected from the Registry for Stones of the Kidney and Ureter (ReSKU) database, a prospectively collected registry of patients with stone disease. Multivariate logistic regression (MLR) was used to estimate the association between stone multiplicity and the decision to perform URS for high stone burden (>20 mm) patients. MLR was further used to estimate the association between performing URS and the following outcomes: stone-free rate, need for a second operation, and complications. Postoperative hospital stay was compared between patients receiving URS vs PCNL using Student's t-test. Results: One hundred twenty-five patients were included in this analysis. For patients with total stone burden exceeding 20 mm, those with more than three stones had roughly nine times the likelihood of undergoing URS over PCNL compared with patients with a single stone (adjusted odds ratio 9.21, confidence interval [95% CI] 2.55-40.58, p = 0.001). Stone-free rates, Clavien-Dindo scores, and frequency of second-look operations did not differ significantly between URS and PCNL patients. URS patients were discharged an average of 1.26 days earlier than patients who received PCNL (95% CI 0.72-1.81, p 20 mm will undergo URS and who will undergo PCNL. These deviations from AUA guidelines do not appear to worsen patient outcomes. These results suggest that careful consideration of each patient may warrant deviation from guidelines.

PurposeNephrolithiasis is an increasingly common ailment in the United States. Ureteroscopic management has supplanted shockwave lithotripsy as the most common treatment of upper tract stone disease. Ureteral stricture is a rare but serious complication of stone disease and its management. The impact of new technologies and more widespread ureteroscopic management on stricture rates is unknown. We describe our experience in managing strictures incurred following ureteroscopy for upper tract stone disease.Materials and methodsRecords for patients managed at four tertiary care centers between December 2006 and October 2015 with the diagnosis of ureteral stricture following ureteroscopy for upper tract stone disease were retrospectively reviewed. Study outcomes included number and type (endoscopic, reconstructive, or nephrectomy) of procedures required to manage stricture.ResultsThirty-eight patients with 40 ureteral strictures following URS for upper tract stone disease were identified. Thirty-five percent of patients had hydronephrosis or known stone impaction at the time of initial URS, and 20% of cases had known ureteral perforation at the time of initial URS. After stricture diagnosis, the mean number of procedures requiring sedation or general anesthesia performed for stricture management was 3.3 ± 1.8 (range 1-10). Eleven strictures (27.5%) were successfully managed with endoscopic techniques alone, 37.5% underwent reconstruction, 10% had a chronic stent/nephrostomy, and 10 (25%) required nephrectomy.ConclusionsThe surgical morbidity of ureteral strictures incurred following ureteroscopy for stone disease can be severe, with a low success rate of endoscopic management and a high procedural burden that may lead to nephrectomy. Further studies that assess specific technical risk factors for ureteral stricture following URS are needed.

An increasing number of patients are utilizing the internet to answer their medical questions. Given the lack of verified stone treatment resources on the web, we sought to evaluate online interest in kidney stone surgical interventions and assess the quality of the most popular resources on social media. Google Trends was used to evaluate public interest in different kidney stone interventions between March 2016 and February 2021 and reported as search volume index (SVI). Next, the social media analysis tool, BuzzSumo, was used to identify stone surgery content online on the social media platforms, YouTube, Instagram, Pinterest, Reddit, and Twitter. To evaluate the quality of health information presented in the online resources, the DISCERN instrument was employed by three individual raters. Ureteroscopy (URS), percutaneous nephrolithotomy (PCNL), and extracorporeal shockwave lithotripsy (SWL) were identified as the top search terms on Google Trends with mean SVIs of 47.75, 42.98, and 45.74, respectively (p = 0.012). On YouTube, URS, PCNL, and SWL had 12,549, 116,222, and 20,717 views, respectively. Nine articles and fifteen videos were chosen for analysis using the DISCERN tool with a mean score of 2.82 and 2.27, respectively, among three independent evaluators. The result of our study suggests that online users are interested in URS but engaged more often with PCNL content on social media platforms. We found that the quality of online resources related to stone surgery highlights the need for involvement of urologists in creation of engaging high-quality content and sharing of accurate information in a social media-driven society. [ABSTRACT FROM AUTHOR]

Background: Managing complex and large renal stones with percutaneous nephrolithotomy (PCNL) is difficult because of the likelihood of residual stones and multiple access. Endoscopic combined intrarenal surgery (ECIRS) is introduced as an improvement to the procedure to manage stones in one session. The objective of this systematic review and meta-analysis is to compare the efficacy and safety between ECIRS and PCNL for treating large and complex renal stones. Materials and Methods: We conducted a systematic review in the Embase, Scopus, and MEDLINE databases based on the 2020 Preferred Reporting Items for Systematic Review and Meta-Analyses guideline. Eligible studies comprised both randomized and nonrandomized studies comparing ECIRS and PCNL. Results: A total of five nonrandomized studies and one randomized controlled trial were included. The analysis was divided into two subgroups based on the PCNL type, a conventional PCNL (cPCNL) and a mini-PCNL (mPCNL). The one-step stone-free rate (SFR) of ECIRS were significantly higher compared with both the cPCNL (odds ratio [OR] 5.14, 95% confidence interval [CI] 2.54 to 10.4, p < 0.001) and mPCNL (OR 4.27, 95% CI 2.57–7.1, p < 0.001). There were no significant differences in mean operative time and hemoglobin drop between both groups (p > 0.05). The use of auxiliary procedures was significantly higher in both PCNL groups compared with the ECIRS group (OR 0.19, 95% CI 0.13–0.30, p < 0.001). The overall complication rate of ECIRS was lower compared with PCNL (OR 0.43, 95% CI 0.21–0.85, p = 0.02), especially urosepsis, in which the incidence was lower compared with cPCNL (OR 0.14, 95% CI 0.02–0.78, p = 0.02), but not mPCNL (p > 0.05). Conclusion: ECIRS is an effective and safe treatment particularly for large and complex nephrolithiasis, with significantly higher one-step SFR, a lower necessity for auxiliary procedures, and a lower complication rate compared with PCNL. [ABSTRACT FROM AUTHOR]

ObjectivesUltrasound-guided percutaneous nephrolithotomy (PCNL) has become increasingly utilized. Patients with nondilated collecting systems represent a challenge: the target calix is often difficult to visualize. Here we report pilot study results for retrograde ultrasound contrast injection to aid in percutaneous renal access during ultrasound-guided PCNL.Patients and methodsFrom April to July 2016, consecutive patients over the age of 18 years with nondilated collecting systems on preoperative imaging who presented for PCNL were enrolled. B-mode ultrasound imaging was compared with contrast-enhanced mode with simultaneous retrograde injection of Optison™ via an ipsilateral ureteral catheter.ResultsFive patients (four males and one female) with renal stones underwent PCNL with retrograde ultrasound contrast injection during the study period. Mean body mass index was 28.3 ± 5.6 kg/m2 and mean stone size was 24.5 ± 12.0 mm. Under B-mode ultrasound, all patients demonstrated nondilated renal collecting systems that appeared as hyperechoic areas, where it was difficult to identify a target calix for puncture. Retrograde contrast injection facilitated delineation of all renal calices initially difficult to visualize under B-mode ultrasound. Renal puncture was then performed effectively in all cases with a mean puncture time of 55.4 ± 44.8 seconds. All PCNL procedures were completed without intraoperative complications and no adverse events related to ultrasound contrast injection occurred.ConclusionRetrograde ultrasound contrast injection as an aide for renal puncture during PCNL is a feasible technique. By improving visualization of the collecting system, it facilitates needle placement in challenging patients without hydronephrosis. Future larger scale studies comparing its use to standard ultrasound-guided technique will be required to validate this concept.

Background: To classify intraoperative and postoperative complications using the modified Clavien classification system (MCCS) and modified Satava classification system (SCS) and to evaluate the parameters associated with complications in patients undergoing retrograde intrarenal surgery (RIRS) for renal and proximal ureteral stones. Materials and Methods: We performed a retrospective analysis of 949 patients who underwent RIRS for renal stones and proximal ureteral stones at two institutions between March 2015 and June 2020. Intraoperative complications were assessed using the SCS, and postoperative complications were graded according to the MCCS. Univariate and multivariate analyses were undertaken to determine predictive factors affecting complication rates. Results: The median stone size was determined as 13 mm (range 10–20 mm). The stone-free rate was 83.6% after the first intervention. Reprocedure was applied to 89 of the patients with residual stones and the final stone-free rate was 94.4% after reprocedure. According to SCS, the number of intraoperative events and complication incidences was 153 (16.1%). MCCS revealed postoperative complications in 121 (12.8%) patients. Major complications were observed in 18 (1.9%) patients. The rate of complications was higher in patients with renal anomalies (9.9% vs 3.4%, p = 0.001). Stone location, stone size, stone burden, stone number, stone density, and residual fragments were determined to be associated with the development of complications (p < 0.001, p < 0.001, p < 0.001, p < 0.001, p = 0.002, and p < 0.001, respectively). In addition, the multivariate analysis revealed that only the presence of residual fragments was a significant predictor of complication development for the patients with Grade ≥3 complications according to MCCS (p = 0.032). However, significant predictors were stone burden (p < 0.001), stone density (p = 0.002), and fluoroscopy time (p < 0.001) for those with Grade ≥2b complications according to SCS. Conclusion: This study showed that abnormal kidney anatomy, operation time, stone burden, and residual fragments were reliable predictors of complication development during and after RIRS. Appropriate preoperative management should be planned according to these predictors to prevent intraoperative and postoperative complications. [ABSTRACT FROM AUTHOR]

Objective: The aim of the study is to propose a visual classification for encrusted stents (ESs) to help choose the appropriate endourologic treatment. Materials and Methods: A multicenter, retrospective, and descriptive study was performed. A total of 140 patients with encrusted Double-J stents were enrolled from 5 different institutions. The novel visual grading for ureteral encrusted stent (V-GUES) classification system ranges from A to D, increasing with severity of encrustation. Results: ESs could be removed with a single intervention in 112 patients (86.8%). Type A and B ESs could be removed in all patients (100% success). Type D stents had minor retrieval and stone-free rates (p = 0.006 and p < 0.0001, respectively). Flexible ureteroscopy had a low success rate (77.7%) for type C stents (odds ratio [OR]: 0.21). Combined access had a 100% success rate for retrieval of type C ESs and a 92.9% success rate for type D ESs (OR: 9.18). Type D stents were associated with patients requiring more than one session to retrieve the stent (OR: 0.11) and stones (OR: 0.21). Conclusions: The V-GUES system is associated with treatment success rates of ES retrieval and stone-free status. It is also associated with the complication rate and the number of sessions needed for patients to be stent and stone free. The V-GUES classification could help counsel patients about the best treatment options and their outcomes. Further prospective studies will be needed to provide external validation. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the clinical value of contrast-enhanced ultrasound (CEUS) in percutaneous nephrolithotomy (PCNL) for kidney stone patients without hydronephrosis. Methods: Patients with nondilated collecting system kidney stones who underwent PCNL between October 2018 and December 2019 at our hospital were enrolled in this study. Patients who met the inclusion criteria were randomized into two groups: a CEUS-guided PCNL group and a conventional ultrasound (US)-guided PCNL group. The operation results of the two groups were compared, including the number of attempts for effective puncture, duration to effective puncture, stone clearance rate, blood loss, postoperative complications, and hospital stay. Results: Fifty-six patients with a nondilated collecting system who underwent PCNL for 60 kidneys were included in this study, including 4 patients who underwent bilateral PCNL due to bilateral renal stones. There were 30 kidneys in each group. All patients successfully underwent PCNL. The CEUS-guided PCNL group had more accurate punctures, with a higher effective rate of one puncture and shorter puncture time. There was no statistically significant difference in stone clearance rate between the two groups. Four cases of double channels were established in the conventional US-guided PCNL group, while there was only one case in the CEUS-guided PCNL group. In the CEUS-guided PCNL group, most cases (96.7%, 29/30) had no or only mild complications, which were significantly better than the conventional US-guided PCNL group (76.7%, 23/30). The mean postoperative hemoglobin loss in the CEUS-guided PCNL group was 9.5 (range 1–25) g/L, which was significantly lower than 15.5 (range 5–52) g/L in the conventional US-guided PCNL group. Conclusion: The CEUS technique can improve visibility of the nondilated renal collecting system, facilitate selection of suitable calix, and identify renal calix fornix. It also benefits needle placement in patients with a nondilated collecting system. [ABSTRACT FROM AUTHOR]

Objectives: To assess the association of skin-to-stone distance (SSD) and stone-free rates following extracorporeal shockwave lithotripsy (SWL) using two statistical methods: logistic regression and a matched-pair analysis approach. Patients and Methods: Patients with a solitary radio-opaque upper ureteral calculus diagnosed on noncontrast computed tomography were included. Patients were treated with a Sonolith I-Sys Lithotripter (focal depth 17 cm). Stone treatment success was defined as stone free (fragments ≤3 mm) at 3 months. Failure was defined as persistent fragments beyond 3 months or requirement for intervention with ureteroscopy. The outcome was assessed by a plain kidney, ureter, and bladder radiograph (KUB) at 2 weeks. Logistic regression was used to determine association of patient and stone factors with treatment failure. The patient cohort was divided into tertiles by SSD, and matched-pair analysis was undertaken between individuals from the top and bottom tertiles (SSD ≤12 cm and SSD ≥14 cm). Matching criteria consisted of age, sex, maximum stone diameter (±2 mm), and stone density (±250 HU). Results: From a database of 2849 patients who underwent SWL, 397 patients were identified who had treatment of a single upper ureteral stone. Age (odds ratio [OR]: 1.03, 95% confidence interval [CI]: 1.01–1.04, p = 0.007), SSD (OR: 1.16, 95% CI: 1.03–1.32, p = 0.02), stone side (OR: 1.65, 95% CI 1.01–2.73, p = 0.05), stone diameter (OR: 1.09, 95% CI: 1.00–1.19, p = 0.05), and multiple sessions (OR: 4.65, 95% CI: 2.61–8.29, p < 0.001) were significantly associated with treatment failure by logistic regression univariable analysis. Multiple sessions was the only factor significantly associated with treatment failure on multivariable analysis (OR: 4.03, 95% CI: 2.18–7.42, p < 0.001). From a cohort of 141 patients with SSD ≥14 cm and 174 patients with a SSD ≤12 cm, 66 matches were identified (132 patients). Forty-nine patients (74.2%) with SSD ≥14 cm were deemed stone free at follow-up vs 51 patients (77.3%) with SSD ≤12 cm (p = 0.85). Conclusion: This study demonstrates by two statistical methods that SWL can provide efficacious treatment of upper ureteral stones in obese patients and that the upper threshold of SSD for SWL with Sonolith I-SYS could be revised to allow these patients the benefits of SWL. [ABSTRACT FROM AUTHOR]

Introduction/Objectives: Despite minimal evidence that evaluates the effect of age on percutaneous nephrolithotomy (PCNL) morbidity, pediatric and elderly patients are considered high-risk groups. Our objective was to assess the effect of the extremes of ages on PCNL readmission and postoperative complication rates. Methods: We identified all PCNL encounters in the 2013 and 2014 Nationwide Readmission Database. Encounters were divided into five age groups: pediatric (<18 years old), young adult (18–25 years old), adult (26–64 years old), geriatric (65–74 years old), and elderly (≥75 years old). Weighted descriptive statistics were used to describe population demographics. We fit an adjusted weighted logistic regression model for 30-day readmission and complication rates. Results: We identified 23,357 encounters. Testing average effect of pediatric and elderly encounters to all other age groups did not reveal a difference in odds for 30-day readmissions, but did result in increased odds for 30-day GU readmissions (odds ratio: 17.7 [95% confidence interval (CI): 2.65–118.9]; p = 0.003). Compared to all other age groups, elderly encounters had 7.5 (95% CI: 2.5–22.7; p = 0.0004) times the odds of a 30-day readmission and 68.3 (95% CI: 29.1–160.4; p < 0.0001) times the odds of a postoperative complication. Conclusions: When comparing the average effect of the extremes of ages to all other age groups, we did not find evidence to suggest a difference in odds for 30-day GU readmissions, but did find increased odds for complications. Further examination revealed that PCNL encounters of elderly patients had significantly increased odds for both readmission and complications, whereas PCNL encounters of pediatric patients did not. [ABSTRACT FROM AUTHOR]

Introduction: A novel semirigid ureterorenoscope, named the Sotn ureterorenoscope, was designed with a vacuum suction system. The present study aimed to evaluate the feasibility and safety of using the Sotn ureterorenoscope to manage single proximal ureteral or renal pelvic stones. Patients and Methods: Data were retrospectively collected from consecutive patients treated with a Sotn ureterorenoscope between February 2010 and August 2015 at Sun Yat-sen Memorial Hospital of Sun Yat-sen University and Jiangmen Wuyi Traditional Chinese Medicine Hospital in China. The primary outcome was the primary stone-free rate (SFR) in 1 month. The secondary outcomes were the final SFR and the perioperative complication rate. Results: A total of 386 patients were evaluated, including 240 males and 146 females. The median (interquartile range [IR]) age was 50 (40–59) years. There were 96 and 290 stones located in the renal pelvis and proximal ureter, respectively. The median (IR) operative time and console time for all patients were 40 (30–70) and 20 (12–38) minutes, respectively. The primary overall SFR was 86.5%, whereas the SFRs for stones with a diameter of ≤1, 1 to 2, and 2 to 3 cm were 95.7%, 86.9%, and 69.0%, respectively. Complications occurred in 90 patients (23.3%); these complications were classified as Clavien–Dindo grades 1 to 2 (minor) in 79 (20.5%) patients, and grades 3 to 4 (major) in 11 (2.8%). Conclusions: The novel semirigid Sotn ureterorenoscope featuring a vacuum suction system is effective and safe for managing proximal ureteral and renal pelvic stones. [ABSTRACT FROM AUTHOR]

Introduction: Moses technology is a novel Holmium:YAG laser system designed to minimize stone retropulsion and improve stone ablation when the laser is not in direct contact with the stone. Our aim was to assess the efficiency of Moses technology relative to short- and long-pulse lithotripsy using an automated in vitro "dusting model" of stone comminution. Methods: All tests were conducted using a Lumenis Pulse 120H Holmium:YAG laser with a 365 μm Moses D/F/L fiber. "Hard" (15:3) and "soft" (15:6) Begostones mimicking calcium oxalate monohydrate and uric acid stones, respectively, were used. To assess ablation efficiency and fiber tip degradation, a dusting model was employed: the laser was moved by a three-dimensional positioning system in a spiral motion across a flat Begostone surface submerged in water. Ablation efficiency was measured as stone mass loss after 4 kJ of energy delivery. Fiber tip degradation was measured at 1 kJ intervals. Comparative trials with short pulse, long pulse, Moses contact, and Moses distance settings were completed with the laser tip positioned at 0, 1, and 2 mm distances from the stone at energy settings of 0.4 J delivered at 70 Hz. Results: In our dusting model, stone ablation was significantly greater the closer the laser was to the stone. On hard stones, pulse type did not have a significant impact on ablation at any distance. On soft stones at 0 mm, Moses contact produced the greatest ablation, significantly greater than long pulse (p < 0.05). At 1 mm, Moses distance produced significantly greater ablation than all other settings (p = 0.025) and was as effective as long or short pulse at 0 mm. At 2 mm distance, no pulse type demonstrated significantly different ablation. Fiber tip degradation was minimal and not significant between settings. Conclusions: Moses technology delivers greater ablation of soft stones when in contact and 1mm from the stone surface. [ABSTRACT FROM AUTHOR]

Objective: To identify avoidable predictors of postureteroscopy (URS) unplanned encounters and to minimize 30-day encounters. Materials and Methods: We performed retrospective chart review and telephone surveys on patients who underwent URS for urolithiasis between January and June 2016. Univariate and multivariable analyses evaluated for potential predictors of unplanned encounters. Results: Of 157 patients, there were 44 (28.0%) unplanned patient-initiated clinical phone calls, 23 (14.6%) emergency department (ED) visits, and 8 (5.1%) readmissions, with pain being the most common complaint during the encounters. Factors associated with a higher rate of phone calls include first-time stone procedure (36.6% vs 20.9%, p = 0.029), outpatient status (30.3% vs 0%, p = 0.021), intraoperative stent placement (31.2% vs 0%, p = 0.006), and stent removal at home (58.8% vs 28.8%, p = 0.014). Factors associated with increased rate of ED visits were first-time stone procedure (22.5% vs 8.1%, p = 0.011) and ureteral access sheath (UAS) usage (29.6% vs 11.8%, p = 0.018). Factors associated with a higher rate of readmissions were lower body mass index (23.9 vs 29.7, p = 0.013), bilateral procedure (20.0% vs 2.9%, p = 0.010), and UAS usage (14.8% vs 3.1%, p = 0.032). Stone burden, operative time, Charlson comorbidity index, and preoperative urinary tract infection were not significantly associated with postoperative encounters. Conclusions: Pain, first-time stone treatment, presence of a ureteral stent, outpatient status, bilateral procedures, and UAS usage were common reasons for postoperative encounters after URS. Appropriate perioperative patient education and counseling and adequate pain management may minimize these encounters and improve treatment quality and patient satisfaction. [ABSTRACT FROM AUTHOR]

Introduction: In the era of minimally invasive surgery, endoscopic and percutaneous interventions for urinary tract stones have become a mainstay, and the need for open stone surgery (OSS) has decreased. We sought to determine the contemporary incidence of OSS among urologists in the United States. Methods: Case logs submitted for certification to the American Board of Urology from 2005 to 2015 were queried for Current Procedural Terminology codes relevant to OSS. Cases were analyzed for the associated practice type, practice area population, geographic region, provider subspecialty, and certifying status of the reporting urologist. Results: A total of 334 cases of OSS were identified, with 73.4% performed by urologists self-identified as generalists. The most common subspecialists performing OSS were endourologists (12.3%). Most cases were done in the private practice setting (80.4%), and in practice areas with populations exceeding 1,000,000 (43.2%). OSS was more commonly reported by urologists applying for recertification than initial certification. Thirty open stone cases were reported each year on average, and there was no decrease in stone cases over time based on linear regression analysis ( R2 = 0.06). OSS was most commonly performed in the Western Section of the American Urological Association (AUA) (25.1%) and least commonly performed in the Northeastern Section (1.5%). A chi-square analysis was performed, and the Western Section had a significantly higher number of OSSs than expected as its urologists represent only 17% of the total AUA membership ( p < 0.01). The Northeastern Section comprises 7% of the AUA membership but only performed 1.5% of OSSs that were significantly lower than expected ( p < 0.001). Conclusions: Domestic performance of OSS remains stable. It is unclear as to whether the majority of these cases could be served by less-invasive technologies or whether the volume represents a true nadir. Future work may be warranted to assess attitudes, training, and feasibility of minimally invasive stone management in areas where OSS is most common. [ABSTRACT FROM AUTHOR]

Introduction: Patients with ileal conduit urinary diversions are at an increased risk of long-term upper urinary tract (UUT) complications, including anastomotic strictures, infections, and urolithiasis. The reconstructed urinary system poses challenges for endoscopic manipulation. We present and describe our dual-center experience in performing retrograde ureteroscopy to treat or diagnose UUT abnormalities in patients with ileal conduit incontinent diversion. Patient and Methods: We performed a retrospective analysis of medical records for all patients with previous urinary diversion who underwent retrograde ureteroscopic procedures via the ileal loop in our institutions over a 9 year period (between June 2007 and August 2016). Results: Fifty-four procedures were performed in 36 patients. Mean age was 61 (28–90) years. Average time from diversion to ureteroscopic procedure was 13.0 (0.08–53) years. Stone disease was the most common indication for intervention in 35.2% (19/54) of cases, with a stone-free rate of 78.9% (15/19). Other indications included surveillance of transitional-cell carcinoma in 22.2% (12/54), diagnostic flexible ureteroscopy (fURS) in 20.4% (11/54), stricture management in 11.1% (6/54), removal of encrusted stent/nephrostomy in 7.4% (4/54), urine leak after diversion in 1.9% (1/54), and miscellaneous in 1.9% (1/54). Successful retrograde access was possible in 74% (40/54) of cases. A long and tortuous ileal segment, too difficult to negotiate, was the most common cause of failure to access the UUT. In 13 out of 54 (24.1%) cases, retrograde fURS was combined with simultaneous percutaneous antegrade access. Six patients (11.1%) developed postprocedural pyrexia requiring additional antibiotic therapy, and one (1.9%) patient required embolization of the renal artery for ongoing bleeding. Median length of stay was 1 day (0–55), with 13 (24%) being performed as day-case procedures. Conclusions: Retrograde ureteroscopy in patients with ileal conduits can be technically challenging due to distorted anatomy. This procedure can be safely performed in experienced hands with standard endourological equipment. An antegrade approach can be carried out simultaneously, which may be required in a small number of patients. [ABSTRACT FROM AUTHOR]

Introduction: Determining whether bacterial presence in urine microscopy represents infection is important as ureteral stent placement is indicated in patients with obstructing urolithiasis and infection. We aim to investigate whether the presence of bacteria on urine microscopy is associated with other markers of infection in patients with obstructing urolithiasis presenting to the emergency room. Methods: We performed a cross-sectional study of 199 patients with obstructing urolithiasis and divided patients into two groups according to the presence of bacteria on urine microscopy. The primary outcome was serum white blood cell count and secondary outcomes were objective fever, subjective fever, tachycardia, pyuria, and final urine culture. Univariate and multivariate analysis were used to assess whether the presence of bacteria on microscopy was associated with other markers of infection. Results: The study included 72 patients in the bacteriuria group and 127 without bacteriuria. On univariate analysis, the presence of bacteria was not associated with leukocytosis, objective fever, or subjective fever, but it was associated with gender ( p < 0.001), pyuria ( p < 0.001), positive nitrites ( p = 0.001), positive leukocyte esterase ( p < 0.001), and squamous epithelial cells ( p = 0.002). In a multilinear regression model including the presence of squamous cells, age, and sex, the presence of bacteriuria was not related to serum white blood cell count (coefficient -0.47; 95% confidence interval [CI] -1.1, 0.2; p = 0.17), heart rate (coefficient 0.85; 95% CI -2.5, 4.2; p = 0.62), presence of subjective or objective fever (odds ratio [OR] 1.5; 95% CI 0.8, 3.1; p = 0.18), or the presence of squamous epithelial cells (coefficient -4.4; 95% CI -10, 1.2; p = 0.12). However, the presence of bacteriuria was related to only the degree of pyuria (coefficient 16.4; 95% CI 9.6, 23.3; p < 0.001). Conclusions: Bacteria on urine microscopy is not associated with other markers of systemic infection and may largely represent a contaminant. Renal colic may be a risk factor for providing a contaminated urine specimen. [ABSTRACT FROM AUTHOR]

Objective: Percutaneous nephrolithotomy (PCNL) is a well-established procedure for the management of urinary calculi and can be performed intercostally or subcostally. Favoring one approach vs the other is still debatable, and literature has been inconclusive regarding the efficacy and safety of both approaches. Hence, this study aims to assess the safety and efficacy of direct non-angled intercostal technique performed under full expiration and to compare it to the subcostal approach. Methods: PCNL was conducted among 361 patients during 2010-2015 at Saint George Hospital University Medical Center in Beirut, Lebanon. PCNL was done by one operator and by following a standard technique. After reviewing the medical records, 304 patients were included. Data analysis was conducted using Stata/IC 10.0. Bivariate analysis was conducted using Pearson's Chi-square, and logistic regression model was run. Alpha level was set at 0.05. Results: Of the total patients, 54.6% and 45.4% underwent intercostal (Group I) and subcostal (Group II) access, respectively. Mean drop in hemoglobin in Group II was 1.9 g/dL vs 1.48 g/dL in Group I ( p-value = 0.0040). The mean difference in operation time between group I (88.61 minutes) and group II (102.58 minutes) was statistically significant ( p-value = 0.0064). Patients were stone free in 88.05% of the intercostal cases and 78.52% of the subcostal cases. Group II patients were twice more likely to have residual stones compared to Group I ( p-value = 0.029). No statistical significance was observed in postoperative complications among both groups. In addition, no cases of pneumothorax were reported. Conclusion: Compared to subcostal access, intercostal approach under full expiration is a safe technique that provides optimal approach to the intrarenal collecting system and allows less angulation, less bleeding, and yields higher stone clearance with minimal complications. When performed by a well-trained urologist, intercostal access should be advocated in PCNL to obtain a direct non-angled access to the tip of the desired posterior calix. [ABSTRACT FROM AUTHOR]

Background: The challenges of training and assessing endourologic skill have driven the development of new training systems. The Center for Research in Education and Simulation Technologies (CREST) has developed a team and a methodology to facilitate this development process. Methods: Backwards design principles were applied. A panel of experts first defined desired clinical and educational outcomes. Outcomes were subsequently linked to learning objectives. Gross task deconstruction was performed, and the primary domain was classified as primarily involving decision-making, psychomotor skill, or communication. A more detailed cognitive task analysis was performed to elicit and prioritize relevant anatomy/tissues, metrics, and errors. Reference anatomy was created using a digital anatomist and clinician working off of a clinical data set. Three dimensional printing can facilitate this process. When possible, synthetic or virtual tissue behavior and textures were recreated using data derived from human tissue. Embedded sensors/markers and/or computer-based systems were used to facilitate the collection of objective metrics. A learning Verification and validation occurred throughout the engineering development process. Results: Nine endourology-relevant training systems were created by CREST with this approach. Systems include basic laparoscopic skills (BLUS), vesicourethral anastomosis, pyeloplasty, cystoscopic procedures, stent placement, rigid and flexible ureteroscopy, GreenLight PVP (GL Sim), Percutaneous access with C-arm (CAT), Nephrolithotomy (NLM), and a vascular injury model. Mixed modalities have been used, including 'smart' physical models, virtual reality, augmented reality, and video. Substantial validity evidence for training and assessment has been collected on systems. An open source manikin-based modular platform is under development by CREST with the Department of Defense that will unify these and other commercial task trainers through the common physiology engine, learning management system, standard data connectors, and standards. Conclusion: Using the CREST process has and will ensure that the systems we create meet the needs of training and assessing endourologic skills. [ABSTRACT FROM AUTHOR]

Ultrasound has become a mainstay tool in urologists' armamentarium for the diagnosis and management of nephrolithiasis. From starting as a rudimentary form of imaging, it has come to play a more prominent role over time, paralleling evolution in ultrasound technology. Throughout the medical community there is a growing emphasis on reducing the amount of ionizing radiation delivered to patients during routine imaging. As such there has been a resurgence of interest in ultrasound given its lack of associated radiation exposure and proven effectiveness as a diagnostic and therapeutic imaging modality. Herein, we provide a review of the history of ultrasound, how the use of ultrasound is expanding in both diagnosis and treatment of urinary stone disease, and finally how promising applications of ultrasound are shaping the future of kidney stone management. [ABSTRACT FROM AUTHOR]

Introduction: Ureteroscopy is increasingly used to treat upper tract urinary stone disease. A negative ureteroscopy is a ureteroscopy performed with the intent of removing a kidney or ureteral stone, but in which ultimately no stone is removed. Negative ureteroscopy may occur when the stone is found to have already passed, or the presumed stone is found to be outside of the collecting system. We sought to determine the rate of negative ureteroscopy in a large population-based sample as well as factors associated with its use. Patients and Methods: We examined nonpublic data from the Office of Statewide Health Planning and Development (OSHPD) Database for all patients in California undergoing outpatient surgery from 2010 to 2012. We identified all patients with an International Classification of Diseases, Ninth Revision (ICD-9) diagnosis code for upper tract urinary stone disease, who underwent a ureteroscopic procedure. After excluding patients undergoing second look procedures or who had diagnosis codes for separate urologic pathology, the negative ureteroscopy rate was defined as the proportion of those ureteroscopy cases coded as a diagnostic ureteroscopy. We fit logistic regression models to evaluate patient factors associated with negative ureteroscopy. Results: During the years 2010 to 2012, 20,236 eligible patients underwent ureteroscopic procedures for upper tract stone disease. Of these, 1287 patients underwent diagnostic ureteroscopy and 19,039 underwent ureteroscopy with stone removal accounting for a negative ureteroscopy rate of 6.3%. The odds of receipt of a negative ureteroscopy rate were higher in females compared to males (odds ratio [OR] 1.41, 95% confidence interval [CI] 1.25, 1.58) and lower in self-pay patients compared with insured patients (OR = 0.55, 95% CI 0.33, 0.91). Conclusions: Negative ureteroscopy is common, occurring in nearly 1 in 16 procedures to treat urinary stone disease. [ABSTRACT FROM AUTHOR]

Objective: To compare the efficacy and morbidity of extracorporeal shockwave lithotripsy (SWL) and flexible ureteroscopy (F-URS) for the management of upper tract urinary stones in children. Methods: All SWL and F-URS performed in children in a single institution between 2000 and 2014 were reviewed retrospectively. Only procedures performed to treat upper tract urinary stones (upper ureter or kidney) were included in this study. Preoperative and perioperative outcomes were compared between the SWL and F-URS groups. Univariate and multivariate logistic regression analyses were used to evaluate predictors of stone-free (SF) status. Results: Over the study period, 100 SWL and 46 F-URS were conducted in 69 children. The SWL and F-URS groups were comparable in terms of stone size (14.6 vs 13.2 mm, p = 0.32), but there were more multiple stones (31% vs 57%; p = 0.003) and lower pole calculi (14% vs 37%; p = 0.003) in the F-URS group. The SF rate after one procedure was almost two times higher in the F-URS group compared with the SWL group (37% vs 21%; p = 0.04) without increasing the complication rate (21.7% vs 16%; p = 0.31). Similar results were observed in the subgroup of single renal stones <20 mm (SF rates: 78.6% vs 50%; p = 0.06). In multivariate analysis, the use of F-URS vs SWL was a predictor of an SF status (odds ratio = 3.7; p = 0.02). Conclusion: F-URS provides a higher single-session SF rate, despite more complex urinary stones (multiple, lower pole, etc.) and without increasing morbidity. [ABSTRACT FROM AUTHOR]

Objective: We compared postoperative outcomes and quality of life (QoL) between patients who received a nephrostomy tube vs a ureteral stent following percutaneous nephrolithotomy (PCNL) in a prospective, double-blind, randomized manner. Materials and Methods: Between September 2015 and March 2016, we randomized 30 patients undergoing PCNL to receive nephrostomy drainage (Group 1: 8F or 10F) or Double-J ureteral stent (Group 2) at conclusion of surgery. Nephrostomy tubes were removed within 48 hours (before discharge) and ureteral stents were removed at least 2 weeks after surgery. Patients' QoL was assessed with the Wisconsin StoneQOL questionnaire preoperatively and then 7 to 10 days and 30 days following surgery. Inclusion criteria included an uncomplicated procedure, normal preoperative renal function, and clinically insignificant residual stone fragments on postoperative imaging. We calculated the preoperative and postoperative QoL score difference between the two groups. We also evaluated perioperative characteristics, inpatient analgesic requirements, length of stay (LOS), and postsurgical complications. Outcome: Patient characteristics between Groups 1 and 2 were comparable with similar age (58.3 vs 54.7, p = 0.534), gender ratio, and stone burden (276.6 mm2 vs 259 mm2, p = 0.84) and composition. There was no significant difference between perioperative outcomes, including stone-free rate (93.3% vs 86.7%), operative times (125.7 minutes vs 115 minutes, p = 0.29), estimated blood loss (103.3 mL vs 100.7 mL, p = 0.9), LOS (3.2 days vs 1.9 days, p = 0.1), and complications (2 in each group). Inpatient analgesic requirements were also the same (both 21.1 mg, p = 1.0). Assessment of QoL using the Wisconsin StoneQOL questionnaire showed significant differences between preoperative and postoperative health-related QoL in 18 of the 28-question instrument at 7 to 10 days. Patients in Group 2 had significantly worse QoL change and a multitude of negative responses on the StoneQOL assessment, not only those commonly associated with stent irritation. Eighty percent of participants in Group 2 also attributed their complaints to having a stent placed. Both groups had similar QoL status at 30 days after surgery. Conclusion: Despite the literature advocating 'tubeless' PCNL with ureteral stent placement at conclusion of surgery, our randomized prospective study shows that QoL is significantly worse with stent placement than with temporary nephrostomy drainage in the immediate aftermath following PCNL, using a validated QoL assessment instrument specific for nephrolithiasis. [ABSTRACT FROM AUTHOR]

Cavitation plays a significant role in the efficacy of stone comminution during shockwave lithotripsy (SWL). Although cavitation on the surface of urinary stones helps to improve fragmentation, cavitation bubbles along the propagation path may shield or block subsequent shockwaves (SWs) and potentially induce collateral tissue damage. Previous in vitro work has shown that applying low-amplitude acoustic waves after each SW can force bubbles to consolidate and enhance SWL efficacy. In this study, the feasibility of applying acoustic bubble coalescence (ABC) in vivo was tested. Model stones were percutaneously implanted and treated with 2500 lithotripsy SWs at 120 SW/minute with or without ABC. Comparing the results of stone comminution, a significant improvement was observed in the stone fragmentation process when ABC was used. Without ABC, only 25% of the mass of the stone was fragmented to particles <2 mm in size. With ABC, 75% of the mass was fragmented to particles <2 mm in size. These results suggest that ABC can reduce the shielding effect of residual bubble nuclei, resulting in a more efficient SWL treatment. [ABSTRACT FROM AUTHOR]

Purpose: We developed a polyethylene sack (the PercSac) that fits over the shaft of a rigid nephroscope and is deployed into the collecting system to capture a stone and contain fragments during percutaneous nephrolithotomy (PCNL). We previously reported our results using the PercSac in a percutaneous cystolithopaxy model. In this study, we compare the efficiency of stone fragmentation with and without the PercSac in an anatomically correct in vitro PCNL model. Materials and Methods: The PCNL model consisted of a human collecting system model created on a 3D printer. Ten BegoStones made in spherical molds of 2.0 cm diameter, matched for weight, were fragmented in the model using a 24F rigid nephroscope and an ultrasonic lithotripter, including five with and five without the PercSac. The total times for stone fragmentation and complete stone clearance, gross assessment of the stonefree status, and need for flexible nephroscopy to achieve a stone-free state were recorded. Results: The median time for stone fragmentation was significantly shorter in the PercSac group compared with the control group (217 seconds [IQR= 169-255] vs 340 seconds [IQR= 310-356], [p = 0.028]). Likewise, the total time for complete stone clearance from the kidney was significantly shorter for the PercSac group (293 seconds [IQR= 244-347] vs 376 seconds [IQR= 375-480], [p = 0.047]). In one trial with the PercSac, residual dust remained in the kidney, while in all five trials without the PercSac small residual fragments remained. All trials without the PercSac required flexible nephroscopy with basket extraction to become stone free, while none of the trials with the PercSac required flexible nephroscopy for stone clearance. Conclusions: Ultrasonic lithotripsy using the novel PercSac stone entrapment device is more efficient and efficacious than traditional ultrasonic lithotripsy in an in vitro PCNL model. The advantage may be even more pronounced during clinical PCNL where residual fragments migrate into difficult-to-access calices. Further in vivo testing is underway. [ABSTRACT FROM AUTHOR]

Introduction: Traditional techniques for obtaining percutaneous renal access utilize continuous fluoroscopy. In an attempt to minimize radiation exposure, we describe a novel laser direct alignment radiation reduction technique (DARRT) for percutaneous access and test it in a bench-top model. Methods: In this randomized-controlled bench-top study, 20 medical personnel obtained renal accesses using both the conventional bullseye technique and the laser DARRT. The primary endpoint was total fluoroscopy time. Secondary endpoints included insertion time, puncture attempts, course corrections, and subjective procedural difficulty. In the laser DARRT, fluoroscopy was used with the C-arm positioned with the laser beam at a 30° angle. The access needle and hub were aligned with the laser beam. Effective caliceal puncture was confirmed with fluoroscopy and direct vision. The Paired samples Wilcoxon signed rank test was used for statistical analysis with significance at p < 0.05. Results: A total of 120 needle placements were recorded. Fluoroscopy time for needle access using the laser DARRT was significantly lower than the bullseye technique in all groups as follows: attendings (7.09 vs 18.51 seconds; p < 0.001), residents (6.55 vs 13.93 seconds; p = 0.001), and medical students (6.69 vs 20.22 seconds; p < 0.001). Students rated the laser DARRT easier to use (2.56 vs 4.89; p < 0.001). No difference was seen in total access time, puncture attempts, or course corrections between techniques. Conclusion: The laser DARRT reduced fluoroscopy time by 63%, compared with the conventional bullseye technique. The least experienced users found the laser DARRT significantly easier to learn. This novel technique is promising and merits additional testing in animal and human models. [ABSTRACT FROM AUTHOR]

Introduction: The incidence of urolithiasis is increasing in the Western population. Significant advances in ureteroscopy and stone fragmentation energy sources have resulted in a paradigm shift in urolithiasis management. We aimed to assess the current state of urolithiasis management in Australia over the last 15 years using population-based data. Methods: Medicare Australia databases were accessed and Medicare rebate codes pertaining to ureteroscopy, extracorporeal shockwave lithotripsy (SWL), and percutaneous nephrolithotomy (PCNL) were extracted per state, year, and gender between 2001 and 2015. Population data were extracted from the Australian Bureau of Statistics website and provided the ''population at risk'' denominator to calculate incidence proportions. Results: From January 2001 to December 2015, 114,789 ureteroscopy or pyeloscopy procedures for stone extraction in adult patients were performed in Australia. During the same period, 48,209 SWL and 6956 PCNL procedures were performed. Ureteroscopy and pyeloscopy procedures have been increasing by an average of 9.3% year-on-year, population adjusted, while SWL has decreased by 3.5% and PCNL by 6.4% every year over the same period. In absolute terms, scope procedures have increased yearly by an average of 3.9 per 100,000 of population (confidence interval [95% CI]: 3.2, 4.5), while SWL has changed by -0.77 (95% CI: -0.88, -0.65) and PCNL by -0.16 (95% CI: -0.17, -0.14). Conclusion: Over the past 15 years in Australia, the total number of stone treatment procedures has increased significantly. Considerable increases in ureteroscopy were observed with relative and absolute reductions in SWL and PCNL. Regional variations in urolithiasis management strategies highlight the need for consensus on stone treatments within Australia. [ABSTRACT FROM AUTHOR]

Introduction: The American Urological Association (AUA) guidelines state that continuing anticoagulation and antiplatelet agents in routine ureteroscopy (URS) is safe and without increased risk of complications. However, these recommendations are based on small case series; thus, we sought to analyze bleeding-related complications among patients on antiplatelet therapy (APT). Materials and Methods: Overall, 4799 URS procedures performed at our institution between June 2009 and February 2016 were identified. Records were then retrospectively reviewed to confirm APT use and to identify periprocedural complications. Antiplatelet agents evaluated included aspirin (low dose and full dose) and P2Y12 receptor antagonists (clopidogrel, prasugugrel, ticagrelor). Patients were excluded if they were taking a concurrent anticoagulant agent or if additional non-URS procedures were performed. Results: Of 4799 URS procedures, 314 (6.5%) were performed on patients taking APT, of which 234 (74.5%) held APT, 63 (20.1%) continued APT, and 17 (5.4%) continued dual APT. The mean age was 70.1 years, and the majority of patients (69.6%) underwent a stone procedure with a stone-free rate of 80.2%. The overall bleedingrelated complication rate was 1.9%, whereas the significant bleeding-related event rate was 1.6% and this did not differ among the groups ( p = 0.3). The power to detect a 3% difference in bleeding between the groups was 0.95. Conclusions: Continuing APT in patients on chronic therapy does not appear to pose an increased risk of bleeding-related complications. Our findings support the current AUA guidelines as they relate to APT. [ABSTRACT FROM AUTHOR]

Objective: To investigate the impact of three-dimensional (3D) printed pelvicaliceal system models on residents' understanding of pelvicaliceal system anatomy before percutaneous nephrolithotripsy (PCNL). Materials and Methods: Patients with unilateral complex renal stones indicating PCNL were selected. Usable data of patients were obtained from CT-scans in Digital Imaging and Communications inMedicine (DICOM) format.Mimics software version 16.0 (Materialise, Belgium) was used for segmentation and extraction of pelvicaliceal systems (PCSs). All DICOM-formatted files were converted to the stereolithography file format. Finally, fused deposition modeling was used to create plasticine 3Dmodels of PCSs.Aquestionnaire was designed so that residents could assess the 3D models' effects on their understanding of the anatomy of the pelvicaliceal system before PCNL (Fig. 3). Results: Five patients' anatomically accurate models of the human renal collecting system were effectively generated (Figs. 1 and 2). After presentation of the 3D models, residents were 86% and 88% better at determining the number of anterior and posterior calices, respectively, 60% better at understanding stone location, and 64% better at determining optimal entry calix into the collecting system (Fig. 5). Conclusion: Generating kidney models of PCSs using 3D printing technology is feasible, and the models were accepted by residents as aids in surgical planning and understanding of pelvicaliceal system anatomy before PCNL. [ABSTRACT FROM AUTHOR]

Background: Percutaneous needle access is a critical step of performing percutaneous nephrolithotomy. Development of a synthetic model that accurately represents the forces encountered while gaining percutaneous renal access, allows for high ease of use and prevention of negative skill transfer. The objectives of this study were to define the needle insertion forces used during percutaneous renal access and to develop a multilayer synthetic physical simulator model based on human tissue data that is compatible with the SimPORTAL fluoroless C-arm trainer (CAT) camera system. Materials and Methods: Needle insertion data were collected using in situ fresh human cadaveric tissue within 72 hours of death. Ultrasound guidance was used to place percutaneous reference needles into the kidney, and axial force vs displacement data was collected using a custom-built force measurement device. A novel multilayer model that includes several types of synthetic materials for simulation of distinct tissue layers was developed based on the human tissue reference data. The multilayer prototype model and an existing single material model were subsequently tested using the same needle insertion protocol and the results were compared with human tissue data. Results: Average maximum forces for needle puncture into skin ranged from 2.75 to 2.80N for human tissue and from 4.53 to 4.19N for simulated human tissue. The overall slope for all force vs displacement data was 0.35 to 0.59 N/cm for human tissue. The overall slope was comparatively lower for the multilayer model (0.17 N/cm) and was highest in the existing single material model (5.08–9.79 N/cm). Conclusions: We have defined the forces for percutaneous renal access using fresh human cadaveric tissue and designed a multilayer synthetic simulator model that can be utilized for training percutaneous needle access to the renal collecting system using the CAT camera system. [ABSTRACT FROM AUTHOR]