Temperature profile during endourological laser activation: introducing the thermal safety distance concept.

PURPOSE: To examine temporal-spatial distribution of heat generated upon laser activation in a bench model of renal calyx. To establish reference values for a safety distance between the laser fiber and healthy tissue during laser lithotripsy. METHODS: We developed an in-vitro experimental setup employing a glass pipette and laser activation under various intra-operative parameters, such as power and presence of irrigation. A thermal camera was used to monitor both temporal and spatial temperature changes during uninterrupted 60-second laser activation. We computed the thermal dose according to Sapareto and Dewey's formula at different distances from the laser fiber tip, in order to determine a safety distance. RESULTS: A positive correlation was observed between average power and the highest recorded temperature (Spearman's coefficient 0.94, p < 0.001). Irrigation was found to reduce the highest recorded temperature, with a maximum average reduction of 9.4 °C at 40 W (p = 0.002). A positive correlation existed between average power and safety distance values (Spearman's coefficient 0.86, p = 0.001). A thermal dose indicative of tissue damage was observed at 20 W without irrigation (safety distance 0.93±0.11 mm). While at 40 W, irrigation led to slight reduction in mean safety distance (4.47±0.85 vs. 5.22±0.09 mm, p = 0.08). CONCLUSIONS: Laser settings with an average power greater than 10 W deliver a thermal dose indicative of tissue damage, which increases with higher average power values. According to safety distance values from this study, a maximum of 10 W should be used in the ureter, and a maximum of 20 W should be used in kidney in presence of irrigation.

Contemporary Diagnostic Work-Up for Male Infertility: Emphasizing Comprehensive Baseline Assessment.

Infertility is a prevalent issue affecting many couples during their reproductive years, with a significant number facing challenges in conceiving despite regular unprotected intercourse. Male factor infertility (MFI) contributes significantly to these cases, with a significant proportion of men lacking an identifiable etiology. As such, a thorough assessment of MFI has become increasingly vital for personalized management. This position paper from the Andrology team at IRCCS Ospedale San Raffaele emphasizes a comprehensive and individualized approach to MFI work-up, addressing the evolving challenges encountered in clinical practice. Our approach involves a thorough diagnostic work-up to identify the underlying causes of MFI, integrating insights from extensive literature review and our proprietary data. Our data demonstrates that an extensive diagnostic assessment allows us to identify at least one underlying cause of MFI in most infertile men. However, challenges persist in diagnosing less severe phenotypes with unclear etiology. We discuss the importance of individualized MFI work-up and its implications for developing rational therapeutic protocols. Lastly, this paper highlights the necessity for a personalized diagnostic assessment, addressing the daily clinical challenges and emphasizing tailored approaches to try to improve outcomes among couples seeking first medical help for infertility.

Endourological society fellowship program: a real contribution to improve surgical outcomes of stone patients treated with ureteroscopy.

PURPOSE: We assessed the impact of the one-year endourological society fellowship program (ESFP) on the achievement of optimal surgical outcomes (OSO) in stone patients treated with ureteroscopy (URS). MATERIALS AND METHODS: We identified 303 stone patients treated with URS from January 2018 to June 2022 by five experienced surgeons (ES). Of those, two attended ESFP. OSO was defined as the presence of residual fragments ≤ 4 mm at 1-month post-operative imaging (Ultrasound + X - Ray or CT scan). Descriptive statistics explored patients' characteristics and the rate of OSO according to the attendance of ESFP. Uni- and multivariate logistic regression analyses (UVA and MVA) tested the impact of stone characteristics, surgical data, ESFP, and imaging technique on the rate of OSO. The LOWESS curve explored the graphical association between stone size and the multivariable-adjusted probability of OSO in the two groups of surgeons. RESULTS: Of 303 patients, 208 (69%) were treated by the two surgeons who attended ESFP. OSO was achieved in 66% and 52% of patients treated by ES with and without ESFP, respectively (p = 0.01). At UVA, ESFP (OR = 1.78; 95% CI = 1.09-2.90), stone diameter (OR = 0.92; 95% CI = 0.88-0.96), stone location (kidney vs. ureter; OR = 0.34; 95% CI = 0.21-0.58), imaging technique (CT scan vs. Ultrasound + X-Ray; OR = 0.28; 95% CI = 0.16-0.47) predicted OSO achievement (all p < 0.05). At MVA analyses, ESFP was associated with OSO (OR = 2.24; 95% CI = 1.29-3.88; p < 0.05), along with the other aforementioned variables. The LOWESS curve showed that the greater the stone size, the greater the difference in OSO in the two groups of surgeons. CONCLUSIONS: ESFP positively affects OSO achievement after URS, especially in patients with a high stone burden.

Acknowledging acute kidney disease following ureteroscopy and laser lithotripsy: results from a tertiary care referral center.

BACKGROUND: Acute kidney disease (AKD) is a recently described syndrome consisting of kidney function abnormalities lasting less than 3 months. Little is known regarding AKD following ureteroscopy (URS) and laser lithotripsy. OBJECTIVE: To evaluate the occurrence and evolution of AKD in stone patients treated with URS. MATERIALS AND METHODS: Data from 284 patients treated with URS for urinary stones were retrospectively analyzed. According to the KDIGO 2020 criteria, AKD was defined as postoperative acute kidney injury (AKI) occurrence, estimated glomerular filtration rate (eGFR) decrease ≥ 35%, or serum creatinine (SCr) increase ≥ 50%. AKI was defined as SCr increase ≥ 0.3 mg/dL or ≥ 50%. AKD evolution was evaluated 60 days post-URS. Data were analyzed using descriptive statistics. Univariable (UVA) and multivariable (MVA) logistic regression analyses tested the association of patients' characteristics and perioperative data with the occurrence of AKD. RESULTS: Overall, postoperative AKD occurred in 32 (11.3%) patients. Recovery from AKD was found in 26 (82%) patients and persistent AKD occurred in 6 (18%) patients. At UVA, age at surgery (p = 0.05), baseline SCr (p = 0.02), baseline CKD category (p = 0.006), Charlson comorbidity index (p = 0.01), operative time (p = 0.04) and postoperative complications (< 0.001) were associated with AKD. At MVA, CKD category (OR 2.99, 95% CI = 1.4-6.3; p = 0.004), operative time (OR 1.01, 95% CI = 1.001-1.018; p = 0.023) and postoperative complications (OR 3.5, 95% CI = 1.46-8.49; p = 0.005) were independent predictors of AKD. CONCLUSIONS: AKD is a frequent complication in patients treated with URS. Moreover, AKD persists in a non-neglectable percentage of patients at medium-term follow-up. Therefore, nephrological assessment should be considered, especially in high-risk patients. Current findings should be considered for the peri-operative management of stone patients.

Role of Follicle-stimulating Hormone, Inhibin B, and Anti-Müllerian Hormone in Predicting Sperm Retrieval from Men with Nonobstructive Azoospermia Undergoing Microdissection Testicular Sperm Extraction: A Systematic Review and Meta-analysis.

Background and objective: No clear-cut markers for predicting positive sperm retrieval (+SR) at microdissection testicular sperm extraction (mTESE) have been identified thus far. Our aim was to conduct a systematic review and meta-analysis to evaluate the ability of follicle-stimulating hormone (FSH), inhibin B (InhB), and anti-Müllerian hormone (AMH) to predict +SR in men with nonobstructive azoospermia (NOA) undergoing mTESE. Methods: We performed a search in the PubMed, EMBASE, Web of Science, and Scopus databases according to the Preferred Reporting Items for Systematic Review and Meta-analysis statement. Thirty-four publications were selected for inclusion in the analysis. Key findings and limitations: Overall, the mean +SR rate was 45%. Pooled standardized mean difference (SMD) values revealed significant hormonal differences between the +SR and -SR groups, with lower FSH (SMD -0.30), higher InhB (SMD 0.54), and lower AMH (SMD -0.56) levels in the +SR group. Pooled odds ratios (Ors) revealed no significant prediction of +SR by either FSH (OR 1.03, 95% confidence interval [CI] 1.00-1.06) or InhB (OR 1.01, 95% CI 1.00-1.02), despite variations in baseline levels and study heterogeneity. Conversely, AMH had significant predictive value (OR 0.82, 95% CI 0.73-0.92), with lower baseline levels in the +SR group. InhB and FSH levels were higher in the +SR group, while InhB exhibited the opposite trend. Conclusions and clinical implications: Despite study heterogeneity, our meta-analysis findings support the ability of AMH to predict +SR for men with NOA undergoing mTESE. Patient summary: We conducted a review and analysis of results from previous studies. Our findings show that for men with an infertility condition called nonobstructive azoospermia, blood levels of anti-Müllerian hormone can predict successful extraction of sperm using a microsurgical technique. Levels of two other hormones did not predict successful sperm extraction.

Rethinking Stone-free Rates and Surgical Outcomes in Endourology: A Point of View from PEARLS Members.

There is a lack of consensus on definitions for the success of endourological stone treatments. The zero-fragment rate (residual fragments [RFs] <1 mm) is now considered more accurate than the stone-free rate (RFs ≤4 mm). As stone volume may be adopted as the recommended method for preoperative estimation of the stone burden, the volumetric stone-free rate may be superior to standard linear RF measurements in defining success.

Natural History of Nonmetastatic Prostate Cancer Managed With Watchful Waiting.

Importance: It is uncertain to what extent watchful waiting (WW) in men with nonmetastatic prostate cancer (PCa) and a life expectancy of less than 10 years is associated with adverse consequences. Objective: To report transitions to androgen deprivation therapy (ADT), castration-resistant prostate cancer (CRPC), death from PCa, or death from other causes in men treated with a WW strategy. Design, Setting, and Participants: This nationwide, population-based cohort study included men with nonmetastatic PCa diagnosed since 2007 and registered in the National Prostate Cancer Register of Sweden with WW as the primary treatment strategy and with life expectancy less than 10 years. Life expectancy was calculated based on age, the Charlson Comorbidity Index (CCI), and a drug comorbidity index. Observed state transition models complemented observed data to extend follow-up to more than 20 years. Analyses were performed between 2022 and 2023. Exposure: Nonmetastatic PCa. Main Outcomes and Measures: Transitions to ADT, CRPC, death from PCa, and death from other causes were measured using state transition modeling. Results: The sample included 5234 men (median [IQR] age at diagnosis, 81 [79-84] years). After 5 years, 954 men with low-risk PCa (66.2%) and 740 with high-risk PCa (36.1%) were still alive and not receiving ADT. At 10 years, the corresponding proportions were 25.5% (n = 367) and 10.4% (n = 213), respectively. After 10 years, 59 men with low-risk PCa (4.1%) and 221 with high-risk PCa (10.8%) had transitioned to CRPC. Ten years after diagnosis, 1330 deaths in the low-risk group (92.3%) and 1724 in the high-risk group (84.1%) were from causes other than PCa. Conclusions and Relevance: These findings suggest that the WW management strategy is appropriate for minimizing adverse consequences of PCa in men with a baseline life expectancy of less than 10 years.

Illumination matters Part II: advanced comparative analysis of flexible ureteroscopes in a kidney model by PEARLS.

PURPOSE: The aim of the study was to evaluate illumination properties in an in-vitro kidney calyx model in saline. DESIGN 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 closed pink kidney calyx model, submerged in saline. A spectrometer was used for illuminance and color temperature measurements at different openings located at center (direct light), 45° (direct and indirect light) and 90°(indirect light) to the axis of the scope. RESULTS: Maximum illuminance was at the center opening for all scopes (range: 284 to 12,058 lx at 50% brightness and 454 to 11,871 lx at 100% brightness settings). The scope with the highest center illuminance (Flex-Xc) was 26 times superior to the scope with the lowest illuminance (Pusen 7.5Fr) at 100% brightness setting. For each scope, there was a peripheral illuminance drop ranging from - 43 to - 92% at 50% brightness and - 43% to - 88% at 100% brightness settings, respectively (all p < 0.01). Highest drop was for the P7 and the Pusen 9.2F. All scopes had illuminance skew, except the V3. All scopes had a warm color temperature. CONCLUSION: Illumination properties vary between ureteroscopes in an enclosed cavity in saline, and differs at center vs 45° and 90° positions within scopes. Peripheral illuminance drop can be as high as - 92%, which is undesirable. This may affect the choice of ureteroscope and light brightness settings used in surgery by urologists.

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.

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.

Fluid dynamics within renal cavities during endoscopic stone surgery: does the position of the flexible ureteroscope and ureteral access sheath affect the outflow rate?

PURPOSE: To evaluate the impact of ureteroscope position within renal cavities as well as different locations of the tip of the ureteral access sheath (UAS) on fluid dynamics during retrograde intrarenal surgery (RIRS). MATERIALS AND METHODS: A prospective observational clinical study was performed. Measurements with a flexible ureteroscope placed in the upper, middle and lower calyces were obtained with the tip of the UAS placed either 2 cm below the pyelo-ureteric junction (PUJ), or at the level of the iliac crest. RESULTS: 74 patients were included. The outflow rates from the middle and upper calyxes were statistically significantly higher compared to the lower calyx, both with the UAS close to the pyelo-ureteric junction and at the iliac crest. When the UAS was withdrawn and positioned at the level of the iliac crest, a significant decrease in outflow rates from the upper (40.1 ± 4.3 ml/min vs 35.8 ± 4.1 ml/min) and middle calyces (40.6 ± 4.0 ml/min vs 36.8 ± 4.6 ml/min) and an increase in the outflow from the lower calyx (28.5 ± 3.3 ml/min vs 33.7 ± 5.7 ml/min) were noted. CONCLUSIONS: Our study showed that higher fluid outflow rates are observed from upper and middle calyces compared to lower calyx. This was true when the UAS was positioned 2 cm below the PUJ and at the iliac crest. Significant worsening of fluid dynamics from upper and middle calyces was observed when the UAS was placed distally at the level of the iliac crest. While the difference was statistically significant, the absolute change was not significant. In contrast, for lower calyces, a statistically significant improvement was documented.

Trends in the use of radiation protection and radiation exposure of European endourologists: a prospective trial from the EULIS-YAU Endourology Group.

INTRODUCTION: Due to the radiation exposure for the urology staff during endourology, our aim was to evaluate the trends of radiation protection in the operation room by endourologists from European centers and to estimate their annual radiation. METHODS: We conducted a multicenter study involving experienced endourologists from different European centers to evaluate whether the protection and threshold doses recommended by the International Commission on Radiation Protection (ICRP) were being followed. A 36-question survey was completed on the use of fluoroscopy and radiation protection. Annual prospective data from chest, extremities, and eye dosimeters were collected during a 4-year period (2017-2020). RESULTS: Ten endourologists participated. Most surgeons use lead aprons and thyroid shield (9/10 and 10/10), while leaded gloves and caps are rarely used (2/10 both). Six out of ten surgeons wear leaded glasses. There is widespread use of personal chest dosimeters under the apron (9/10), and only 5/10 use a wrist or ring dosimeter and 4 use an eye dosimeter. Two endourologists use the ALARA protocol. The use of ultrasound and fluoroscopy during PCNL puncture was reported by 8 surgeons. The mean number of PCNL and URS per year was 30.9 (SD 19.9) and 147 (SD 151.9). The mean chest radiation was 1.35 mSv per year and 0.007 mSv per procedure. Mean radiation exposure per year in the eyes and extremities was 1.63 and 11.5 mSv. CONCLUSIONS: Endourologists did not exceed the threshold doses for radiation exposure to the chest, extremities and lens. Furthermore, the ALARA protocol manages to reduce radiation exposure.

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.

The Importance of Discordant Follicle Stimulating Hormone and Inhibin B Levels in Primary Infertile Men: Findings from a Cross-Sectional Study.

PURPOSE: We aimed to investigate the relationship between follicle stimulating hormone (FSH) and inhibin B (InhB). MATERIALS AND METHODS: Data from 1,230 consecutive men presenting for primary couple's infertility were analyzed. Health-significant comorbidities were scored with Charlson comorbidity index. Quartiles of FSH and InhB were considered to determine threshold values. Descriptive statistics and logistic regression models tested association between FSH and InhB values. RESULTS: Overall, 1,080 (87.8%) men had concordant FSH and InhB values. Conversely, 150 patients (12.2%) had discrepancies in FSH and InhB, with 78 (6.3%) and 72 (5.9%) men reporting both low and high FSH and InhB values, respectively. Infertile men with discordant values were younger (median [interquartile range] 38.0 years [34-41 years] vs. 36.0 years [31-40 years]); had smaller testicular volume (TV) (12 mL [10-15 mL] vs. 15 mL [12-20 mL]); and, had more frequently a sperm DNA fragmentation test >30% (179 [59.1%] vs. 40 [78.4%]) than those with concordant values (all p<0.05). Moreover, a higher frequency of previous cryptorchidism (27.3% vs. 11.9%), lower sperm concentration (3.0 million/mL [0.9-11.0 million/mL] vs. 13.8 million/mL [3.1-36.0 million/mL]), lower progressive sperm motility rates (12.0% [5.0%-25.3%] vs. 20.0% [7.0%-36.0%]), and greater rates of non-obstructive azoospermia (36.4% vs. 23.9%) were found in men with discordant FSH and InhB values (all p≤0.005). At multivariable logistic regression analysis, higher body mass index (odds ratio [OR], 1.08; p=0.001), smaller TV (OR, 0.91; p<0.001), and a history of cryptorchidism (OR, 2.49; p<0.001) were associated with discordant FSH and InhB values. CONCLUSIONS: More than one out of ten infertile men had discordant FSH and InhB values in the real-life setting showing worse clinical profiles than those with concordant levels. Smaller TV and history of cryptorchidism could be used as clinical markers to better tailor the need to test InhB.

A historical comparison of thulium fiber laser systems for stone lithotripsy: navigating toward safe and effective parameters.

INTRODUCTION AND OBJECTIVES: Medical device companies have introduced new TFL machines, including Soltive (Olympus, Japan), Fiber Dust (Quanta System, Italy), and TFLDrive (Coloplast, France). The primary objective of this study is to compare our initial clinical experiences with TFL using those devices. Through this historical comparison of Thulium Fiber Laser systems for stone lithotripsy, we aim to advance our understanding and approach toward achieving safe and effective TFL parameters. MATERIALS AND METHODS: The data for this comparative analysis were extracted from three distinct prospective series that were previously published, outlining our initial clinical experience with the Soltive (Olympus, Japan), FiberDust laser (Quanta System, Italy), and TFLDrive laser (Coloplast, France). Parameters such as stone size, stone density, laser-on time (LOT), and laser settings were meticulously recorded. Additionally, we assessed critical variables such as ablation speed (expressed in mm3/s) and Joules/mm3 for each lithotripsy procedure. RESULTS: A total of 149 patients were enrolled in this study. Among them, 120 patients were subjected to analysis concerning renal stones. Statistically significant differences were observed in the median (IQR) stone volume: 650 (127-6027) mm3 for TFLDrive, 1800 (682.8-2760) mm3 for Soltive, and 1125 (294-4000) mm3 for FiberDust (p: 0.007); while there were no differences regarding stone density among the groups. Significant variations were identified in median (IQR) pulse energy, frequency, and total power. The Soltive group exhibited lower energy levels (0.3 J vs. 0.6 J, p: 0.002) but significantly higher pulse frequency (100 Hz vs. 17.5 Hz, p: 0.003) and total power (24 W vs. 11W, p: 0.001) compared to the other groups. Laser-on time showed no substantial differences across all three groups. Additionally, a statistically significant difference was observed in median J/mm3, with the TFLDrive group using higher values (24 J/mm3, p: 0.001), while the Soltive group demonstrated a higher median ablation speed of 1.16 mm3/s (p: 0.001). The overall complication rate remained low for all groups, with comparable stone-free rates. CONCLUSION: By reducing pulsed frequency, we improved laser efficiency, but smaller volumes lead to decreased efficiency due to increased retropulsion and fragment movement. Further studies are needed to identify and establish the appropriate laser settings for this new technology.

Worldwide trends of practice and intervention in paediatric endourology: comparison of European versus Non-European responses.

Introduction: The area of paediatric endourology is unique and is recognised to be challenging, and it requires a certain level of focused training and expertise. Our aim was to conduct a worldwide survey in order to gain an overview regarding the current practice patterns for minimally invasive treatments of paediatric upper urinary tract stone patients. Material and methods: The survey was distributed between December 2021 and April 2022 through urology sections and societies in United Kingdom, Latin America and Asia. The survey was made up of 20 questions and it was distributed online using the free online Google Forms (TM). Results: 221 urologists answered the survey with 56 responses each from India, South America and UK and 53 responses from the rest of Europe (15 countries). In total, 163 responders (73.7%) managed paediatric stone patients in their daily practice. Of the responders, 60.2% were adult urologists and 39.8% were paediatric urologists. 12.9% adult urologists and 20.4% paediatric urologists run independent clinics while some run combined adult and paediatric clinics sometimes with the support of the nephrologists. Only 33.9% urologists offered all surgical treatments [extracorporeal shock wave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL), ureteroscopy (URS) and retrograde intrarenal surgery (RIRS)]. Conclusions: Treatment of paediatric stones can vary according to country and legislations. Based on the results of this survey, minimally invasive methods such as URS and mini PCNL seem to have become more popular. In most institutions a collaboration exists between adult and paediatric urologists, which is the key for a tailored decision making, counselling and treatment success.