Intrarenal pressures during flexible ureteroscopy: an insight into safer endourology.

OBJECTIVES: To assess intrarenal pressures (IRPs) and complication rates after flexible ureteroscopy (fURS), and to assess factors that contribute to raised IRPs and postoperative complications. PATIENTS AND METHODS: After informed consent patients underwent fURS under general anaesthesia. The transducer of a 0.3556 mm (0.014″) pressure guidewire was placed in the renal pelvis for live recording of IRPs. The fURS procedures were performed in a routine manner under antibiotic cover with the aim of dusting the calculus to completion. The operating surgeon was blinded to the live-recorded IRPs. RESULTS: A total of 40 fURS procedures were performed in 37 patients (26 male and 11 female). The mean age was 50.5 years. As a cohort, the mean of average IRPs was 34.8 mmHg and the mean of maximal IRPs was 128.8 mmHg. Pearson's correlation showed a significant inverse correlation between the mean IRP and age (r[38]: -0.391, P = 0.013). Three cases experienced postoperative deviations from uncomplicated recovery, with two being hypotensive and one case being both hypotensive and hypoxic. Three cases returned to the emergency department within 30 days of surgery, with two cases of flank pain and one case of urosepsis with positive urine cultures. The patient presenting with urosepsis had exhibited IRPs exceeding the mean. CONCLUSION: The IRPs changed significantly from normal baseline levels during routine fURS. The mean IRP during fURS correlates with patient age, but not with other factors. The IRP may be related to increased complication rates at fURS. Understanding factors that influence IRP will allow urologists to better manage this intraoperatively.

Perspectives on technology: to use or to reuse, that is the endoscopic question-a systematic review of single-use endoscopes.

OBJECTIVE: To compare clinical outcomes of single-use endoscopes with those of reusable endoscopes to better define their role within urology. METHODS: A systematic search of electronic databases was performed. All studies comparing the clinical outcomes of participants undergoing urological procedures with single-use endoscopes to those of participants treated with reusable endoscopes were included. Results are reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 statement. RESULTS: Twenty-one studies in 3943 participants were identified. Six different single-use flexible ureteroscopes and two different single-use flexible cystoscopes were assessed. There were no differences in mean postoperative infection rates (4.0% vs 4.4%; P = 0.87) or overall complication rates (11.5% vs 11.9%; P = 0.88) between single-use and reusable endoscopes. For patients undergoing flexible ureteroscopy there were no differences in operating time (mean difference -0.05 min; P = 0.96), length of hospital stay (LOS; mean difference 0.06 days; P = 0.18) or stone-free rate (SFR; 74% vs 74.3%; P = 0.54) between the single-use and reusable flexible ureteroscope groups. CONCLUSION: This study is the largest to compare the clinical outcomes of single-use endoscopes to those of reusable endoscopes within urology, and demonstrated no difference in LOS, complication rate or SFR, with a shorter operating time associated with single-use flexible cystoscope use. It also highlights that the cost efficiency and environmental impact of single-use endoscopes is largely dependent on the caseload and reprocessing facilities available within a given institution. Urologists can therefore feel confident that whether they choose to 'use' or to 'reuse' based on the financial and environmental implications, they can do so without negatively impacting patient outcomes.

Percutaneous nephrolithotomy vs retrograde intrarenal surgery for renal stones: a Cochrane Review.

OBJECTIVES: To assess the effects of percutaneous nephrolithotomy (PCNL) vs retrograde intrarenal surgery (RIRS) for the treatment of renal stones in adults. METHODS: We performed a comprehensive search of the Cochrane Library, MEDLINE, Embase, three other databases, trials registries, other sources of the grey literature, and conference proceedings up to 23 March 2023. We applied no restrictions on publication language or status. Screening, data extraction, risk-of-bias assessment, and certainty of evidence (CoE) rating using the Grading of Recommendations Assessment, Development and Evaluations (GRADE) approach were done in duplicate by two independent reviewers. This co-publication focuses on the primary outcomes of this review only. RESULTS: We included 42 trials that met the inclusion criteria. Stone-free rate (SFR): PCNL may improve SFRs (risk ratio [RR] 1.13, 95% confidence interval [CI] 1.08-1.18; I2 = 71%; 39 studies, 4088 participants; low CoE). Major complications: PCNL probably has little to no effect on major complications (RR 0.86, 95% CI 0.59-1.25; I2 = 15%; 34 studies, 3649; participants; moderate CoE) compared to RIRS. Need for secondary interventions: PCNL may reduce the need for secondary interventions (RR 0.31, 95% CI 0.17-0.55; I2 = 61%; 21 studies, 2005 participants; low CoE) compared to RIRS. CONCLUSION: Despite shortcomings in most studies that lowered our certainty in the estimates of effect to mostly very low or low, we found that PCNL may improve SFRs and reduce the need for secondary interventions while not impacting major complications. Ureteric stricture rates may be similar compared to RIRS. We expect the findings of this review to be helpful for shared decision-making about management choices for individuals with renal stones.

Semirigid ureteroscopy and tamsulosin therapy as dilatation methods before flexible ureteroscopy: evaluation and benefits.

OBJECTIVE: To evaluate the effect of semirigid ureteroscopy and tamsulosin therapy as dilatation methods before flexible ureteroscopy advancement to the renal collecting system. PATIENTS AND METHODS: This prospective study included patients with renal stones less than 2 cm who underwent retrograde flexible ureteroscopy and laser lithotripsy. The patients were randomized into two groups: group A patients were given a placebo for 1 week before flexible ureteroscopy, and group B patients were administered 0.4 mg of tamsulosin once daily for 1 week before surgery and underwent active dilatation using semirigid ureteroscopy before flexible ureteroscopy. The ability of the flexible ureteroscope to reach the collecting system in both groups during the same operative session was assessed. Operative outcomes and complications were collected and analyzed in both groups. RESULTS: A total of 170 patients were included in our study, with each group comprising 85 patients. In group B, the flexible ureteroscope successfully accessed the kidney in 61 patients, while in group A, the flexible ureteroscope was successful only in 28 cases (71.4% versus 32.9%). In group A, 33 (38.8%) patients had lower urinary tract symptoms compared to 17 (20.2%) patients in group B (P = 0.013). CONCLUSION: Using tamsulosin therapy and semirigid ureteroscopy as dilatation methods before flexible ureteroscopy increased the success of primary flexible ureteroscopy advancement to renal collecting system.

Arterial pseudoaneurysm: a rare complication following laser lithotripsy-case series and literature review.

OBJECTIVE: To perform a comprehensive narrative review that will examine the risk factors and treatment outcomes of arterial pseudoaneurysm following laser flexible ureteroscopy (F-URS). METHODS: A retrospective case series and a review of literature was performed. Clinical records from three patients treated for postoperative arterial pseudoaneurysm from January of 2021 to November 2023 were identified. A comprehensive literature review was also performed. The MEDLINE and Scopus databases were searched. The analysis was made by a narrative synthesis. RESULTS: Three cases of postoperative arterial pseudoaneurysm were included, one from our center, one from Dubai, UAE, and one from Barcelona. The literature review identified six case reports, two after endocorporeal laser lithotripsy with thulium fiber laser (TFL) and four with Ho:YAG laser. All cases, from our series and literature review, presented with macroscopic hematuria and used high-power laser settings. All cases were treated by selective embolization. CONCLUSION: Ho:YAG or TFL lasers are both capable of causing arterial pseudoaneurysms following F-URS if high-power settings are used. Selective artery embolization continues to be the treatment of choice with good outcomes.

Risk factors of early infectious complications after ureterorenoscopy for stone disease: a prospective study.

PURPOSE: To prospectively evaluate the rate and associated risk factors of early infectious complications after ureterorenoscopy for urolithiasis. METHODS: After ethical committee approval, 400 therapeutic retrograde ureterorenoscopy procedures between August 3, 2020 and November 24, 2021 were included for analysis in a single-center study. Postoperative infection was defined as an afebrile urinary tract infection, fever (≥ 38 °C) with pyuria (≥ 300 WBC/µL) or proven urinary pathogen, and urosepsis. The primary outcome was the rate of infectious complications after ureterorenoscopy. Secondary outcomes were the perioperative factors that increased the risk of infectious complications within 30 days of surgery using univariate and multivariate logistic regression analysis. RESULTS: Twenty-nine of four hundred (7.3%) patients developed an infectious complication within 30 days after ureterorenoscopy. Ten (2.5%) patients developed an afebrile urinary tract infection, eight (2.0%) developed fever with pyuria, five (1.3%) febrile urinary tract infection, and six (1.5%) urosepsis. On univariate analysis, preoperative stent-type JFil® pigtail suture stent was significantly associated with the dependent variable (p < 0.001). On multivariate logistic regression analysis, older age (OR 1.035; 95% CI 1.006-1.070; p = 0.02) was found to be significantly associated with developing a postoperative infectious complication. CONCLUSIONS: A 7.3% rate of postoperative infectious complications and 1.5% urosepsis rate were observed after therapeutic ureterorenoscopy, without the need of intensive care admission. The only significant risk factors were preoperative stent type (JFil® pigtail suture stent) on univariate analysis, and older age on multivariate logistic regression analysis. Further multicentric prospective observational data are needed in this field.

Extracorporeal shock wave lithotripsy versus laser lithotripsy in the treatment of post-SWL steinstrasse: a randomized comparative study.

OBJECTIVE: To compare the efficacy of Holmium laser lithotripsy with that of extracorporeal shock lithotripsy (SWL) for post-SWL ureteral steinstrasse. MATERIALS AND METHODS: From January 2022 to July 2023, 36 patients with post-SWL ureteral steinstrasse were randomly divided into laser lithotripsy and SWL groups. Patients with pain, moderate to marked hydronephrosis, large leading stone fragments, and showing no spontaneous resolution within 3-4 weeks after medical expulsive therapy were included. Patients with sepsis were excluded. The success rate was the primary outcome. We compared the perioperative data between the groups. RESULTS: The success rate was higher in the ureteroscopy group than in the SWL group (p = 0.034). SWL was a significantly longer operation, and the fluoroscopy time was significantly longer in the SWL group than in the URS group (p = 0.027). Auxiliary procedures were more frequently performed in the SWL group than in the URS group (p = 0.02). JJ stents were inserted in 100% of patients in the URS group. Three patients (16.7%) underwent conversion to laser ureteroscopy after the second SWL session failed. No significant difference in the incidence of postoperative complications was observed between the groups, but the incidence of postoperative LUT was high in the ureteroscopy group. The mean hospital stay was 30 h in the ureteroscopy group. SWL was performed without the need for hospital admission. CONCLUSION: Ureteroscopic laser lithotripsy for steinstrasse was safe and effective, with a higher success rate, shorter fluoroscopy time, and shorter recovery period than SWL.

Unveiling the challenges of UTUC biopsies and cytology: insights from a global real-world practice study.

PURPOSE: Diagnostic ureteroscopy (dURS) is optional in the assessment of patients with upper tract urothelial carcinoma (UTUC) and provides the possibility of obtaining histology. METHODS: To evaluate endoscopic biopsy techniques and outcomes, we assessed data from patients from the CROES-UTUC registry. The registry includes multicenter prospective collected data on diagnosis and management of patients suspected having UTUC. RESULTS: We assessed 2380 patients from 101 centers. dURS with biopsy was performed in 31.6% of patients. The quality of samples was sufficient for diagnosis in 83.5% of cases. There was no significant association between biopsy techniques and quality (p = 0.458). High-grade biopsy accurately predicted high-grade disease in 95.7% and high-risk stage disease in 86%. In ureteroscopic low-grade tumours, the prediction of subsequent low-grade disease was 66.9% and low-risk stage Ta-disease 35.8%. Ureteroscopic staging correctly predicted non-invasive Ta-disease and ≥ T1 disease in 48.9% and 47.9% of patients, respectively. Cytology outcomes did not provide additional value in predicting tumour grade. CONCLUSION: Biopsy results adequately predict high-grade and high-risk disease, but approximately one-third of patients are under-staged. Two-thirds of patients with low-grade URS-biopsy have high-risk stage disease, highlighting the need for improved diagnostics to better assess patient risk and guide treatment decisions. CLINICAL TRIAL REGISTRATION: The study was registered at ClinicalTrials.gov (ClinicalTrials.gov NCT02281188; https://clinicaltrials.gov/ct2/show/NCT02281188 ).

Preoperative urine culture with contaminants is not associated with increased risk for urinary tract infection after ureteroscopic stone treatment.

PURPOSE: We aimed to assess whether the presence of contaminants in the pre-operative urine culture (preop-UC) predicts postoperative urinary tract infection (postop-UTI) in patients undergoing elective ureteroscopy with laser lithotripsy. METHODS: A retrospective chart review was performed from 01/2019 to 12/2021 examining patients with unilateral stone burden ≤ 2 cm who underwent ureteroscopy with laser lithotripsy and had a preop-UC within 3 months. Positive, negative, contaminated, and polymicrobial definitions for UCs were established in accordance with current guidelines. Patients with positive and polymicrobial cultures were excluded. Postop-UTI was defined as the presence of urinary symptoms and a positive UC within 30 days of the procedure. Multivariable logistic regression models were utilized to evaluate risk factors for contamination in the preop-UC and the risk of postop-UTI. RESULTS: A total of 201 patients met the inclusion-exclusion criteria. Preop-UC was negative in 153 patients and contaminated in 48 patients. Significant contaminant-related factors included female gender and increased BMI. Postop-UTI was diagnosed in 3.2% of patients with negative preop-UCs and 4.2% of patients with contaminants, with no difference between groups (p = 0.67). The regression model determined that the presence of contaminants in preop-UC failed to predict postop-UTI (OR 0.69, p = 0.64). CONCLUSION: The presence of contaminants in preop-UCs is not associated with an increased risk of postop-UTIs after ureteroscopy. Our study supports that contaminants in the preop-UC can be interpreted as a negative UC in terms of postop-UTI risk stratification. Preoperative antibiotics should not be prescribed for patients undergoing uncomplicated ureteroscopy for stone surgery in the setting of a contaminated preop-UC.

Illumination matters part I: comparative analysis of light sources and illumination in flexible ureteroscopy-fundamental findings from a PEARLS analysis.

PURPOSE: Illumination characteristics of flexible ureteroscopes have been evaluated in air, but not in saline, the native operative medium for endourology. The aim was to evaluate light properties of contemporary ureteroscopes in air versus saline, light distribution analysis, and color temperature. METHODS: We evaluated the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, and OTU WiScope using a 3D printed black target board in-vitro model submerged in saline. A spectrometer was used for lux and color temperature measurements at different opening locations. RESULTS: Illuminance was higher in saline compared to air (5679 vs. 5205 lx with Flex-Xc, p = 0.02). Illuminance in saline differed between ureteroscopes (ANOVA p < 0.001), with highest for the Flex-Xc at 100% brightness setting (5679 lx), followed by Pusen 9.2F (5280 lx), Flex-X2s (4613 lx), P7 (4371 lx), V3 (2374 lx), WiScope (582 lx) and finally Pusen 7.5F (255 lx). The same ranking was found at 50% brightness setting, with the highest ureteroscope illuminance value 34 times that of the scope with lowest illuminance. Most scopes had maximum illuminance off center, with skewness. Three scopes had two light sources, with one light source for all other scopes. Inter-scope comparisons revealed significant differences of color temperature (ANOVA p < 0.001). CONCLUSION: The study demonstrates the presence of inhomogeneous light spread as well as large differences in illumination properties of ureteroscopes, possibly impacting on the performance of individual scopes in vivo. Additionally, the study suggests that future studies on illumination characteristics of flexible ureteroscopes should ideally be done in saline, and no longer in air.

Illumination matters part IV: blackout and whiteout in flexible ureteroscopy - first report on a phenomenon observed by PEARLS.

PURPOSE: To date, no study has evaluated effects of varying brightness settings on image quality from flexible ureteroscopes submerged in saline. The aim was to evaluate blackout and whiteout occurrences in an in-vitro kidney calyx model. MATERIAL AND METHODS: We evaluated a series of contemporary flexible ureteroscopes including the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, as well as OTU WiScope using a 3D-printed enclosed pink in-vitro kidney calyx model submerged in saline. Endoscopic images were captured with ureteroscope tip placed at 5 mm,10 mm and 20 mm distances. The complete range of brightness settings and video capture modes were evaluated for each scope. Distribution of brightness on a grayscale histogram of images was analyzed (scale range 0 to 255). Blackout and whiteout were defined as median histogram ranges from 0 to 35 and 220 to 255, respectively (monitor image too dark or too bright for the human eye, respectively). RESULTS: Blackout occurred with the P7, Pusen 7.5F, 9.2F and WiScope at all distances, and V3 at 20 mm - with lowest brightness settings. Whiteout occurred with Flex-X2s, V3 and P7 at 5 mm and 10 mm, as well as with V3 and P7 at 20 mm - mostly with highest brightness settings. The Flex-Xc had neither blackout nor whiteout at all settings and distances. CONCLUSION: Blackout or whiteout of images is an undesirable property that was found for several scopes, possibly impacting diagnostic and therapeutic purposes during ureteroscopy. These observations form a guide to impact a urologist's choice of instruments and settings.

A machine learning approach using stone volume to predict stone-free status at ureteroscopy.

INTRODUCTION: To develop a predictive model incorporating stone volume along with other clinical and radiological factors to predict stone-free (SF) status at ureteroscopy (URS). MATERIAL AND METHODS: Retrospective analysis of patients undergoing URS for kidney stone disease at our institution from 2012 to 2021. SF status was defined as stone fragments < 2 mm at the end of the procedure confirmed endoscopically and no evidence of stone fragments > 2 mm at XR KUB or US KUB at 3 months follow up. We specifically included all non-SF patients to optimise our algorithm for identifying instances with residual stone burden. SF patients were also randomly sampled over the same time period to ensure a more balanced dataset for ML prediction. Stone volumes were measured using preprocedural CT and combined with 19 other clinical and radiological factors. A bagged trees machine learning model with cross-validation was used for this analysis. RESULTS: 330 patients were included (SF: n = 276, not SF: n = 54, mean age 59.5 ± 16.1 years). A fivefold cross validated RUSboosted trees model has an accuracy of 74.5% and AUC of 0.82. The model sensitivity and specificity were 75% and 72.2% respectively. Variable importance analysis identified total stone volume (17.7% of total importance), operation time (14.3%), age (12.9%) and stone composition (10.9%) as important factors in predicting non-SF patients. Single and cumulative stone size which are commonly used in current practice to guide management, only represented 9.4% and 4.7% of total importance, respectively. CONCLUSION: Machine learning can be used to predict patients that will be SF at the time of URS. Total stone volume appears to be more important than stone size in predicting SF status. Our findings could be used to optimise patient counselling and highlight an increasing role of stone volume to guide endourological practice and future guidelines.

Play it safe: renal function after bilateral flexible ureteroscopy for kidney stones.

PURPOSE: We searched for perioperative renal function deterioration risk factors in patients that underwent bilateral flexible ureteroscopy (fURS) for kidney stones. METHODS: From August 2016 to February 2020, symptomatic patients > 18 years old with bilateral kidney stones up to 20 mm in each side were prospectively studied. Serum creatinine samples were collected on admission to surgery, immediate postoperative (IPO), on POD 3, 10, and 30. Estimated glomerular filtration rate (eGFR) was calculated using Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) without a race coefficient. RESULTS: Thirty patients underwent bilateral fURS. Comparing to preoperative eGFR, median IPO and POD3 eGFR (p < 0.001) were significantly lower, and POD10 (p = 0.092) and POD30 (p = 0.648) were similar to preoperative eGFR. During follow-up, 22/30 (73.3%), 14/30 (46.7%), and 7/30 (23.3%) of the patients presented a decrease > 10% eGFR, > 20% eGFR, and > 30% eGFR, respectively. Multivariate analysis demonstrated that lower preoperative eGFR is a risk factor for eGFR < 60 mL/min/1.73 m2, p = 0.019 [1.021-1.263; 1.136]; ASA > 1 is a risk factor for decrease of eGFR > 10%, p = 0.028 [1.25-51.13; 8.00]; longer operative time is a risk factor for decrease of eGFR > 20%, p = 0.042 [1.00-1.05; 1.028]; and operative time ≥ 120 min is a risk factor for decrease of eGFR > 30%, p = 0.026 [0.016-0.773; 0.113]. CONCLUSIONS: Renal function suffers a reversible decrease after bilateral fURS. Our study suggests that adequate selection of patients and maintaining operative time < 120 min are relevant factors in preventing acute renal function deterioration following bilateral fURS.

Ureteroscopic management in cystinuric patients: long-term results from a tertiary care referral center.

OBJECTIVE: To evaluate long-term surgical and functional outcomes of cystinuric patients exclusively treated with Ureteroscopy (URS). METHODS: Data from patients treated for cystine stones at a single academic center were retrospectively analyzed. The management protocol consisted of (i) treating symptomatic or > 7 mm stones, (ii) multi-staged URS for voluminous stones, (iii) referring patients to a dedicated nephrological clinic. The eGFR was calculated according to the MDRD formula. CKD category was assessed according to the NKF classification. Relevant CKD was defined as CKD category ≥ 3a. Descriptive statistics were used to analyze the cohort data. RESULTS: Data from 46 cystinuric patients treated with 332 URS were available. Median age at diagnosis and at first URS in our center were 18 and 32 years, respectively. Median follow-up was 101 months. Median number of URS and recurrences per patient were 6 and 2, respectively. The median interval between the first and the last available creatinine level was 64 months. Median first and last eGFR were 72 and 74 mL/min, respectively. Overall, 83% of patients had stable or improved renal function within the study period. Ureteral stricture occurred in 3 (6.5%) patients. CONCLUSIONS: Cystinuria requires intensive endoscopic management. Most patients treated with URS have stable or improved renal function within a long-term follow-up. CKD is a not neglectable event that potentially occurs at an early stage of life. Current findings should be considered for the surgical management of cystinuric patients.

Cost-effectiveness of quality improvement intervention to reduce time between CT-detection and ureteroscopic laser fragmentation in acute symptomatic ureteric stones management.

OBJECTIVE: To prospectively assess clinical and cost effectiveness of emergency ureteroscopic laser fragmentation of urinary stones causing symptoms or obstruction. PATIENTS AND METHODS: 100 consecutive patients with an average (median) age 55.6 (57.5) years and average (median) stone size of 8.2 mm (± 7 mm) between October 2018 and December 2021 who underwent emergency ureteroscopy and laser fragmentation formed the study cohort as part of a clinical service quality improvement. Primary outcome was single procedure stone-free rate and cost-effectiveness. The secondary outcomes were complications, re-admission and re-intervention. A decision analysis model was constructed to compare the cost-effectiveness of emergency ureteroscopy with laser fragmentation (EUL) and emergency temporary stenting followed by delayed ureteroscopy with laser fragmentation (DUL) using our results and success rates for modelling. RESULTS: Single procedure stone-free rates (SFR) for EUL and DUL were 85%. The re-intervention rate, re-admission and complication rates of the study cohort (EUL) were 9%, 18%, and 4%, respectively, compared to 15%, 20%, and 5%, respectively for the control cohort (DUL). The decision analysis modelling demonstrated that the EUL treatment option was more cost-efficient, averting £2868 (€3260) per patient for the UK health sector. Total cost of delayed intervention was £7783 (€8847) for DUL in contrast to £4915 (€5580) for EUL. CONCLUSIONS: Implementation of quality improvement project based on a reduction in CT detection-to-laser fragmentation time interval in acute ureteric obstruction or symptoms caused by stones had similar clinical effectiveness compared to delayed ureteroscopic management, but more cost-effective.

Illumination matters Part III: Impact of light obstruction on illuminance from flexible ureteroscopes - a comparative PEARLS analysis.

PURPOSE: Artifacts from poor ureteroscopes' light design with shadowing and dark areas in the field of view have been reported. The aim was to quantify effects of light obstruction in a kidney calyx model. METHODS: We evaluated a series of contemporary flexible ureteroscopes including the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, as well as OTU Wiscope using an enclosed 3D-printed pink in vitro kidney calyx model submerged in saline, where the field of light was intentionally partially obstructed alternatively at 12, 3, 6, and 9 o'clock. A color spectrometer was used for illuminance measurements at a 45° opening position in the background of the model. RESULTS: Overall and mean background illuminance for each obstructive situation were significantly different between scopes for both 50% and 100% brightness settings (ANOVA p < 0.001). At 50% brightness setting, almost all scopes had their highest and lowest background illuminance with the 6 o'clock and 3 o'clock obstructive situation, respectively. At 100% brightness setting, these became 6 o'clock and 12 o'clock obstructive situations. Considering each obstructive situation individually, the Flex-Xc was consistently the scope with highest background illuminance and the Pusen 7.5F the lowest. Background illuminance for each obstructive situation varied significantly for each scope individually, with the greatest range of variability for Pusen 7.5F and V3. CONCLUSIONS: Illuminance performance of ureteroscopes within an obstructed calyx model differ significantly for various obstructive situations. Urologists should be aware of this to help guide their choice of ureteroscope.

Assessing renal tissue temperature changes and perfusion effects during laser activation in an in vivo porcine model.

INTRODUCTION: High fluid temperatures have been seen in both in vitro and in vivo studies with laser lithotripsy, yet the thermal distribution within the renal parenchyma has not been well characterized. Additionally, the heat-sink effect of vascular perfusion remains uncertain. Our objectives were twofold: first, to measure renal tissue temperatures in response to laser activation in a calyx, and second, to assess the effect of vascular perfusion on renal tissue temperatures. METHODS: Ureteroscopy was performed in three porcine subjects with a prototype ureteroscope containing a temperature sensor at its tip. A needle with four thermocouples was introduced percutaneously into a kidney with ultrasound guidance to allow temperature measurement in the renal medulla and cortex. Three trials of laser activation (40W) for 60 s were conducted with an irrigation rate of 8 ml/min at room temperature in each subject. After euthanasia, three trials were repeated without vascular perfusion in each subject. RESULTS: Substantial temperature elevation was observed in the renal medulla with thermal dose in two of nine trials exceeding threshold for tissue injury. The temperature decay time (t½) of the non-perfused trials was longer than in the perfused trials. The ratio of t½ between them was greater in the cortex than the medulla. CONCLUSION: High-power laser settings (40W) can induce potentially injurious temperatures in the in vivo porcine kidney, particularly in the medullary region adjacent to the collecting system. Additionally, the influence of vascular perfusion in mitigating thermal risk in this susceptible area appears to be limited.

Advancements in stone classification: unveiling the beauty of urolithiasis.

PURPOSE: Urolithiasis has become increasingly prevalent, leading to higher disability-adjusted life years and deaths. Various stone classification systems have been developed to enhance the understanding of lithogenesis, aid urologists in treatment decisions, and predict recurrence risk. The aim of this manuscript is to provide an overview of different stone classification criteria. METHODS: Two authors conducted a review of literature on studies relating to the classification of urolithiasis. A narrative synthesis for analysis of the studies was used. RESULTS: Stones can be categorized based on anatomical position, size, medical imaging features, risk of recurrence, etiology, composition, and morphoconstitutional analysis. The first three mentioned offer a straightforward approach to stone classification, directly influencing treatment recommendations. With the routine use of CT imaging before treatment, precise details like anatomical location, stone dimensions, and Hounsfield Units can be easily determined, aiding treatment planning. In contrast, classifying stones based on risk of recurrence and etiology is more complex due to dependencies on multiple variables, including stone composition and morphology. A classification system based on morphoconstitutional analysis, which combines morphological stone appearance and chemical composition, has demonstrated its value. It allows for the rapid identification of crystalline phase principles, the detection of crystalline conversion processes, the determination of etiopathogenesis, the recognition of lithogenic processes, the assessment of crystal formation speed, related recurrence rates, and guidance for selecting appropriate treatment modalities. CONCLUSIONS: Recognizing that no single classification system can comprehensively cover all aspects, the integration of all classification approaches is essential for tailoring urolithiasis patient-specific management.

Development and validation of a novel home-made bench-top training model for retrograde intrarenal surgery.

PURPOSE: To develop and validate a low-cost homemade bench-top training model to facilitate retrograde intrarenal surgery (RIRS) training. METHODS: The RIRS training model (G-Model) was developed using a surgical glove and a recycled ureter access sheath. Fifteen participants including 10 residents and 5 urologists were enrolled. Designed training curriculum for residents was carried out. Face validity, content validity, construct validity and criterion validity evaluation of the G-Model were carried out. RESULTS: The global score of face and content validity was 4.15 ± 0.53 and 4.65 ± 0.29, respectively. For construct validity, the overall modified global rating scale (mGRS) score was significantly improved [12.5 (5.25) vs. 24.0 (5.25), p = 0.004], and the total task time was significantly shortened (39.5 ± 4.48 min vs. 24.1 ± 3.81 min, p < 0.001) within residents after G-Model training. The baseline mGRS score and total task time of residents were poorer than those of urologists [12.5 (5.25) vs. 32.0 (1.00), p < 0.001; 39.5 ± 4.48 min vs. 16.0 ± 1.58 min, p < 0.001]. Spearman correlation analysis revealed strong correlations between residents' G-Model and real patient performance. CONCLUSION: The current study presented a valid low-cost easily accessible RIRS bench-top training model which could facilitate skill acquisition and translate to real-life scenario.

Radiation exposure of urologists during endourological procedures: a systematic review.

INTRODUCTION: Ionizing radiation is used daily during endourological procedures. Despite the dangers of both deterministic and stochastic effects of radiation, there is a lack of knowledge and awareness among urologists. This study reviewed the literature to identify the radiation exposure (RE) of urologists during endourological procedures. METHODS: A literature search of the Medline, Web of Science, and Google Scholar databases was conducted to collect articles related to the radiation dose to urologists during endourological procedures. A total of 1966 articles were screened. 21 publications met the inclusion criteria using the PRIMA standards. RESULTS: Twenty-one studies were included, of which 14 were prospective. There was a large variation in the mean RE to the urologist between studies. PCNL had the highest RE to the urologist, especially in the prone position. RE to the eyes and hands was highest in prone PCNL, compared to supine PCNL. Wearing a thyroid shield and lead apron resulted in a reduction of RE ranging between 94.1 and 100%. Educational courses about the possible dangers of radiation decreased RE and increased awareness among endourologists. CONCLUSIONS: This is the first systematic review in the literature analyzing RE to urologists over a time period of more than four decades. Wearing protective garments such as lead glasses, a thyroid shield, and a lead apron are essential to protect the urologist from radiation. Educational courses on radiation should be encouraged to further reduce RE and increase awareness on the harmful effects of radiation, as the awareness of endourologists is currently very low.