International Alliance of Urolithiasis (IAU) guidelines on the management of pediatric urolithiasis.

The aim of this study was to construct the sixth in a series of guidelines on the treatment of urolithiasis by the International Alliance of Urolithiasis (IAU) that by providing a clinical framework for the management of pediatric patients with urolithiasis based on the best available published literature. All recommendations were summarized following a systematic review and assessment of literature in the PubMed database from January 1952 to December 2023. Each generated recommendation was graded using a modified GRADE methodology. Recommendations are agreed upon by Panel Members following review and discussion of the evidence. Guideline recommendations were developed that addressed the following topics: etiology, risk factors, clinical presentation and symptoms, diagnosis, conservative management, surgical interventions, prevention, and follow-up. Similarities in the treatment of primary stone episodes between children and adults, incorporating conservative management and advancements in technology for less invasive stone removal, are evident. Additionally, preventive strategies aiming to reduce recurrence rates, such as ensuring sufficient fluid intake, establishing well-planned dietary adjustments, and selective use pharmacologic therapies will also result in highly successful outcomes in pediatric stone patients. Depending on the severity of metabolic disorders and also anatomical abnormalities, a careful and close follow-up program should inevitably be planned in each pediatric patient to limit the risk of future recurrence rates.

Outcomes and considerations for retrograde intrarenal surgery (RIRS) in the setting of multiple and large renal stones (>15 mm) in children: Findings from multicentre and real-world setting.

Purpose: The aim of this study is to evaluate the outcomes of retrograde intra renal surgery (RIRS) in the setting of large or multiple stones in children (<18 years). Materials and Methods: Retrospective analysis was performed of paediatric RIRS cases at nine centres worldwide over a 6-year period. Patients were divided into two groups: Group 1 had a single stone <15 mm. Group 2 had either multiple stones, maximum stone diameter of >15 mm, or both. Outcomes included stone free rate (SFR) and complications within 30 days. Results: In total, 344 patients were included with 197 and 147 in Groups 1 and 2, respectively. Ureteric access sheaths were more frequently used in Group 2 (39.5% vs. 56.8%, p = 0.021). The operation time was significantly longer in Group 2 (p < 0.001). SFR after a single procedure was 84.7% in Group 1 and 63.7% in Group 2. Overall complication rates in Groups 1 and 2 were 7.6% and 33.3%, respectively. The most frequently reported complication in both groups was post-operative fever (4.4% vs. 14%, p = 0.004). The rate of Clavien I/II complications in groups 1 and 2 was 6% and 25.1%, respectively (p < 0.05). The rate of Clavien ≥ III complications in groups 1 and 2 was 1.6% and 8.1%, respectively (p < 0.05). On multivariate analysis, total operation time, stone size and multiplicity were significant predictors of residual fragments. Conclusions: RIRS can be performed in paediatric cases with large and multiple stone burdens, but the complication rate is significantly higher when compared to smaller stones.

The Utility and Safety of Ureteral Access Sheath During Retrograde Intrarenal Surgery in Children.

OBJECTIVE: To compare retrograde intrarenal surgery (RIRS) with and without ureteral access sheath (UAS) in different pediatric age groups. METHODS: The data of RIRS for kidney stone in children were obtained from 9 institutions. Demographic characteristics of patients and stones, intraoperative and postoperative results were recorded. While analyzing the data, patients who underwent RIRS without UAS (group 1) (n = 195) and RIRS with UAS (group 2) (n = 194) were compared. RESULTS: Group 1 was found to be young, thin, and short (P <.001, P = .021, P <.001), but there was no gender difference and similar symptoms were present except hematuria, which was predominant in group 2 (10.6% vs 17.3%, P <.001). Group 1 had smaller stone diameter (9.91 ± 4.46 vs 11.59 ± 4.85 mm, P = .001), shorter operation time (P = .040), less stenting (35.7% vs 72.7%, P = .003). Re-intervention rates and stone-free rates (SFR) were similar between groups (P = .5 and P = .374). However, group 1 had significantly high re-RIRS (P = .009). SFR had a positive correlation with smaller stone size and thulium fiber laser usage compared to holmium fiber laser (HFL) (P <.001 and P = .020), but multivariate analysis revealed only large stone size as a risk factor for residual fragments (P = .001). CONCLUSION: RIRS can be performed safely in children with and without UAS. In children of smaller size or younger age (<5 years), limited use of UAS was observed. UAS may be of greater utility in stones larger than 1 cm, regardless of the age, and using smaller diameter UAS and ureteroscopes can decrease the complications.

Experts' recommendations in laser use for the treatment of bladder cancer: a comprehensive guide by the European Section of Uro-Technology (ESUT) and Training and Research in Urological Surgery and Technology (TRUST)-Group.

PURPOSE: To identify laser settings and limits applied by experts during laser vaporization (vapBT) and laser en-bloc resection of bladder tumors (ERBT) and to identify preventive measures to reduce complications. METHODS: After a focused literature search to identify relevant questions, we conducted a survey (57 questions) which was sent to laser experts. The expert selection was based on clinical experience and scientific contribution. Participants were asked for used laser types, typical laser settings during specific scenarios, and preventive measures applied during surgery. Settings for a maximum of 2 different lasers for each scenario were possible. Responses and settings were compared among the reported laser types. RESULTS: Twenty-three of 29 (79.3%) invited experts completed the survey. Thulium fiber laser (TFL) is the most common laser (57%), followed by Holmium:Yttrium-Aluminium-Garnet (Ho:YAG) (48%), continuous wave (cw) Thulium:Yttrium-Aluminium-Garnet (Tm:YAG) (26%), and pulsed Tm:YAG (13%). Experts prefer ERBT (91.3%) to vapBT (8.7%); however, relevant limitations such as tumor size, number, and anatomical tumor location exist. Laser settings were generally comparable; however, we could find significant differences between the laser sources for lateral wall ERBT (p = 0.028) and standard ERBT (p = 0.033), with cwTm:YAG and pulsed Tm:YAG being operated in higher power modes when compared to TFL and Ho:YAG. Experts prefer long pulse modes for Ho:YAG and short pulse modes for TFL lasers. CONCLUSION: TFL seems to have replaced Ho:YAG and Tm:YAG. Most laser settings do not differ significantly among laser sources. For experts, continuous flow irrigation is the most commonly applied measure to reduce complications.

A multicentric non-randomized prospective observational study on the clinical efficiency of thulium fibre laser in large volume stones (> 1000 mm3).

PURPOSE: Our objective was to analyse the clinical efficiency of TFL in large volume stones during retrograde intrarenal surgery. MATERIALS AND METHODS: Patients with large volume renal stones (> 1000 mm3) operated at two different centres, from May 2020 to April 2021, were enrolled in this study. Retrograde intrarenal surgery was performed using 60W Superpulse thulium fibre laser™ (IPG Photonics, Russia). Demographic data, stone parameters, laser time, and total operating time were recorded, and laser efficacy (J/mm3) and ablation speed (mm3/s) were calculated. NCCT KUB was done at 3 months postoperatively to calculate stone-free rate. RESULTS: A total of 76 patients were included and analysed in the study. Mean stone volume was 1753.12 ± 1245.81 (1169.27-2193.25) mm3, mean stone density was 1104.46 ± 313.09 (875.00-1317.00) HU, mean laser time was 537.79 ± 689.89 (21.00-1080.00) sec, mean operating time was 43.38 ± 12.96 (35.00-51.25) min, mean laser efficacy was 20.30 ± 15.5 (8.88-25.57) J/mm3, and mean ablation speed was 1.32 ± 0.7 (0.82-1.64) mm3/sec. A strong positive correlation was found between the stone volume and ablation speed (r = 0.659, p = 0.000), and a moderate negative correlation was found between the stone volume and laser efficacy (J/mm3) (r = - 0.392, p = 0.000). With increasing volume of the stone, J/mm3 decreased significantly and ablation speed increased significantly (p < 0.001). Complications occurred in 21.05% (16/76) patients, most of which were Clavien grades 1-2. Overall SFR is 96.05%. CONCLUSION: Laser efficiency increases at higher stone volumes (> 1000 mm3), as less energy is required to ablate every mm3 of stone.

Improving Outcomes of Same-sitting Bilateral Flexible Ureteroscopy for Renal Stones in Real-world Practice-Lessons Learnt from Global Multicenter Experience of 1250 Patients.

Background: Bilateral kidney stones are commonly treated in staged procedures. Objective: To evaluate outcomes after same-sitting bilateral retrograde intrarenal surgery (SSB-RIRS) for renal stones. Design setting and participants: Data from adults who underwent bilateral RIRS in 21 centers were retrospectively reviewed (from January 2015 to June 2022). The inclusion criteria were unilateral/bilateral symptomatic bilateral stone(s) of any size/location in both kidneys and bilateral stones on follow-up with symptom/stone progression. Stone-free rate (SFR) was defined as absence of any fragment >3 mm at 3 mo. Outcome measurements and statistical analysis: Continuous variables are presented as medians and 25-75th percentiles. A multivariable logistic regression analysis was performed to evaluate independent predictors of sepsis and bilateral SFR. Results and limitations: A total of 1250 patients were included. The median age was 48.0 (36-61) yr. Of the patients, 58.2% were prestented. The median stone diameter was 10 mm on both sides. Multiple stones were present in 45.3% and 47.9% of the left and right kidneys, respectively. Surgery was stopped in 6.8% of cases. The median surgical time was 75.0 (55-90) min. Complications were transient fever (10.7%), fever/infection needing prolonged stay (5.5%), sepsis (2%), and blood transfusion (1.3%). Bilateral and unilateral SFRs were 73.0% and 17.4%, respectively. Female (odds ratio [OR] 2.97, 95% confidence interval [CI] 1.18-7.49, p = 0.02), no antibiotic prophylaxis (OR 5.99, 95% CI 2.28-15.73, p < 0.001), kidney anomalies (OR 5.91, 95% CI 1.96-17.94, p < 0.001), surgical time ≥100 min (OR 2.86, 95% CI 1.12-7.31, p = 0.03) were factors associated with sepsis. Female (OR 1.88, 95% CI 1.35-2.62, p < 0.001), bilateral prestenting (OR 2.16, 95% CI 1.16-7.66, p = 0.04), and the use of high-power holmium:YAG laser (OR 1.63, 95% CI 1.14-2.34, p < 0.01) and thulium fiber laser (OR 2.50, 95% CI 1.32-4.74, p < 0.01) were predictors of bilateral SFR. Limitations were retrospective study and no cost analysis. Conclusions: SSB-RIRS is an effective treatment with an acceptable complication rate in selected patients with kidney stones. Patient summary: In this large multicenter study, we looked at outcomes after same-sitting bilateral retrograde intrarenal surgery (SSB-RIRS) for renal stones in a large cohort. We found that SSB-RIRS was associated with acceptable morbidity and good stone clearance after a single session.

Comparison of Low-Power vs High-Power Holmium Lasers in Pediatric Retrograde Intrarenal Surgery Outcomes.

Objectives: To compare the outcomes of using low-power (up to 30 W) vs high-power (up to 120 W) holmium lasers in retrograde intrarenal surgery (RIRS) in children and to analyze if lasering techniques and the use of access sheath have any influence on the outcomes. Methods: We retrospectively reviewed data from 9 centers of children who underwent RIRS with holmium laser for the treatment of kidney stones between January 2015 and December 2020. Patients were divided into two groups: high-power and low-power holmium laser. Clinical, perioperative variables and complications were analyzed. Outcomes were compared between groups using Student's t-test for continuous variables, and Chi-square and Fisher's exact test for categorical variables. A multivariable logistic regression analysis model was also performed. Results: A total of 314 patients were included. A high-power and low-power holmium laser was used in 97 and 217 patients, respectively. Clinical and demographic variables were comparable between both groups, except for stone size where the low-power group treated larger stones (mean 11.11 vs 9.70 mm, p = 0.018). In the high-power laser group, a reduction in surgical time was found (mean 64.29 vs 75.27 minutes, p = 0.018) with a significantly higher stone-free rate (SFR) (mean 81.4% vs 59%, p < 0.001). We found no statistical differences in complication rates. The multivariate logistic regression model showed lower SFR in the low-power holmium group, especially with larger (p = 0.011) and multiple stones (p < 0.001). Conclusion: Our real-world pediatric multicenter study favors high-power holmium laser and establishes its safety and efficacy in children.

Role of Preoperative Ureteral Stent on Outcomes of Retrograde Intra-Renal Surgery (RIRS) in Children. Results From a Comparative, Large, Multicenter Series.

OBJECTIVE: To assess outcomes of pre-stenting versus non-pre-stenting in children undergoing retrograde intrarenal surgery (RIRS) for intrarenal stones. METHODS: Children/adolescent with kidney stones undergoing RIRS in 9 centers between 2015 and 2020 were retrospectively reviewed. EXCLUSION CRITERIA: ureteral lithotripsy, bilateral procedures. Stone-free status was evaluated at 3-month and defined as a single residual fragment (RF) ≤2 mm/absence of multiple fragments. Patients were divided into two groups (Group 1 no-prestenting; Group 2 prestenting). Student's, Chi-square and Fisher's exact test was used to assess difference between groups. Univariable and multivariable logistic regression analysis were performed to predict RF. Statistical significance: P-value <0.05. RESULTS: Three hundred eighty-nine children/adolescents were included (192 patients in Group 1). Prestented patients were younger compared with non-prestented (mean age 8.30 ± 4.93 vs 10.43 ± 4.30 years, P < 0.001). There were no differences in stone characteristics (number, size, locations). Lasing and total surgical time were similar. Urinary tract infections were more prevalent in Group 2 (10.7%) compared to Group 1 (3.7%, P = 0.016). Sepsis occurred in 2.1% of patients in Group 2 and no patient in Group 1 (P = 0.146). 30.7% patients in Group 1 and 26.4% in Group 2 had RF (P = 0.322). In univariate logistic regression analysis, stone size was associated with RF (OR 1.12 95%CI 1.06-1.18, P < 0.001), whereas Thulium fiber laser with a lower incidence (OR 0.24 95%CI 0.06-0.69, p=0.020). Multivariate logistic regression analysis showed that stone size was associated with RF (OR 1.20 95%CI 1.08-1.36, P = 0.001). CONCLUSIONS: RIRS showed similar stone-free rate in pre and non-prestented children/adolescents, although prestented patients were younger. A higher risk of post-operative infections was reported in prestented patients.

Durability of current generation flexible ureteroscopes: the experience from a high-volume centre.

Introduction: The aim of this article was to evaluate the durability of current generation fibreoptic flexible ureteroscopes (FURS), analyse factors that influence durability, identify reasons for premature damage of FURS and offer suggestions to expand its life span. Material and methods: A total of 952 retrograde intrarenal surgeries (RIRS) done for upper tract calculi using 8 fibreoptic FURS, namely three Storz Flex X2, one Flex X2S, two Olympus URF- P6, two Olympus URF- P7, between March 2013 and December 2018, were reviewed retrospectively. All procedures were done by two consultants, in a single referral centre. Data relating to stone characteristics and flexible ureteroscopy procedure were retrieved from hospital database. The primary end point was damage of FURS requiring first repair. Results: The average stone burden was 14.59 ±3.37 mm (range 3-22 mm). Ureteral access sheath was used in 95.4% of cases, 36.7% of the cases were pre-stented. Mean ureteroscope durability was 119 procedures and mean ureteroscopy time was 71.99 hours of use before first repair. Prolonged laser usage time and increased usage of accessories had significant negative impact on longevity of FURS (p = 0.002, p = 0.036 respectively). Inadvertent laser fibre misfire and extreme torque caused premature FURS damage, at the end of 35 and 12 procedures respectively. Conclusions: Current generation fibreoptic flexible ureteroscopes have a mean durability of 119 procedures. Anticipation of torque, knowledge of the common reasons for damage and meticulous handling is essential to maximise the durability of FURS.

The clinical efficiency and safety of 60W superpulse thulium fiber laser in retrograde intrarenal surgery.

Introduction: Our aim is to evaluate the clinical efficiency and safety of 60W Thulium fiber laser (TFL) during retrograde intrarenal surgery (RIRS). The performance of the TFL across different ranges of stone volumes and stone densities is assessed. Materials and Methods: Between October 2019 and August 2020, a prospective study was done on 135 patients with < 20 mm renal stones, who underwent RIRS using TFL. Stone parameters, total laser time, total energy delivered (kJ), and fiber burn-back were recorded. Laser efficacy (J/mm3) and ablation speed (mm3/s) were calculated. Results: Data of 126 of 135 patients included in the study were analyzed. The mean patient age was 45.04 ± 12.30 years. Mean stone size was 15.19 ± 4.52 mm, and mean stone volume was 1061.85 ± 806.81 mm3. Mean laser time was 19.78 ± 12.32 min. At higher stone volume (>1000 mm3), J/mm3 decreased significantly from 16.18 ± 5.90 to 10.92 ± 3.21 (P < 0.001) and the ablation speed increased significantly (0.77 ± 0.28-1.04 ± 0.28 mm3/s [P < 0.001]). Stone density did not have a significant influence on the laser efficacy [B = -0.31 (-2.45 to 1.82, p=0.771)] or on the ablation speed [B = -0.06 (-0.17 to 0.05, p=0.278)]. Overall SFR was 93.6%. The complication rate was 16.6% (21/126). Out of the 21, 12 patients had hematuria and 9 had fever, which were of Clavien grades 1-2. Conclusion: Superpulse TFL is efficient and safe. The work efficiency increases for larger volume stones. The work efficiency remains the same across different stone densities. No complication more than Clavien grade 2 was encountered.

Outcomes and lessons learnt from practice of retrograde intrarenal surgery (RIRS) in a paediatric setting of various age groups: a global study across 8 centres.

PURPOSE: To analyse and report the practice, outcomes and lessons learnt from a global series of retrograde intrarenal surgery (RIRS) in a paediatric multicentre series. METHODS: A retrospective review of anonymized pooled data gathered globally from 8 centres in paediatric patients (≤ 18 years of age) who had renal stones and underwent RIRS from 2015 to 2020 was performed. Patient demographics, perioperative parameters, stone characteristics, complications and stone-free rate (SFR; defined as endoscopically stone free and/or residual fragments < 2 mm on follow up imaging) were analysed. The cohort was stratified into 3 groups by age: < 5 years (Group A), 5-10 years (Group B) and > 10 years (Group C). Overall, post-operative complication rate was 13.7%. Chi-square comparisons were used for categorical variables; analysis of variance (ANOVA) or Kruskal-Wallis tests were used for continuous variables. RESULTS: 314 patients were analysed. The mean age was 9.54 ± 4.76 years. Groups A, B and C had 67 (21.3%), 83 (26.4%) and 164 (52.2%) patients, respectively. Mean stone size was 10.7 ± 4.62 mm. Pre-stenting was performed in 155 (49.4%) of patients, ureteral access sheaths (UAS) was used in 54.5% of patients with majority (71%) utilizing holmium laser for stone fragmentation. All complications were minor (Clavien-Dindo grade 1 and 2). SFR was 75.5%. CONCLUSIONS: RIRS is acceptable as a first-line intervention in the paediatric population with reasonable efficacy and low morbidity. Complications are slightly higher in patients < 5 years of age, which should be taken into account while counselling patients.

Real-world Global Outcomes of Retrograde Intrarenal Surgery in Anomalous Kidneys: A High Volume International Multicenter Study.

OBJECTIVE: To analyze the trends and outcomes of retrograde intrarenal surgery for treatment of urolithiasis in anomalous kidneys in a large international multicenter series. MATERIALS AND METHODS: We designed a multicentric retrospective study. Nineteen high-volume centers worldwide were included. Pre-, peri- and postoperative data were collected, and a subgroup analysis was performed according to renal anomaly. RESULTS: We analyzed 414 procedures: 119 (28.7%) were horseshoe kidneys, 102 (24.6%) pelvic ectopic kidneys, 69 (16.7%) malrotated kidneys and 50 (12.1%) diverticular calculus. The average size (SD) of the stone was 13.9 (±6) millimeters and 193 (46.6%) patients had a pre-operative stent. In 249 cases (60.1%) a disposable scope was used. A UAS (ureteral access sheath) was used in 373 (90%) patients. A Holmium laser was used in 391 (94.4%) patients. The average (SD) operating time was 65.3 (±24.2) minutes. Hematuria, caliceal perforation and difficulty in stone localisation were mostly seen in diverticular stones and difficulty in UAS placement and lithotripsy in the cases of renal malrotation. The overall complication rate was 12%. Global stone-free rate was 79.2%. Residual fragments (RF) were significantly lesser in the pre-stented group (P <.05). Diverticular calculi was the group with more RF and needed ancillary procedures (P <.05). CONCLUSION: Retrograde intrarenal surgery in patients with anomalous kidneys is safe and effective with a high single-stage stone-free rate and low complication rate. There is a trend toward using smaller and disposable scopes and smaller UAS. Diverticular stones can still be challenging with higher rates of intraoperative hematuria, caliceal perforation and RF.

Supine percutaneous nephrolithotomy in a 9-month infant.

Treatment of nephrolithiasis in infants is challenging. There are no separate guidelines for the management of renal stones in infants. There is a recent surge in doing PCNL in supine position. Literature is lacking regarding the feasibility and safety of supine PCNL in infants. We report a case of supine PCNL in 9-month-old female baby. We report our case to insist on the feasibility, safety and advantages of supine PCNL even in less than 1 year age group.

Emphysematous pyelonephritis with gas in inferior vena cava.

Emphysematous pyelonephritis (EPN) is a progressive necrotizing infection of the renal parenchyma, collecting system and perinephric tissue. A 36-year female with uncontrolled diabetes, presented with left emphysematous pyelonephritis, with air in the infra-hepatic inferior vena cava (IVC). She was hydrated, treated with intravenous antibiotics, insulin. Percutaneous nephrostomy with Double J stenting was done in modified supine position. Patient was discharged with nephrostomy. Two weeks later, flexible ureterorenoscopy was done and obstructing papillary necrosis removed. Pneumo-vena cava due to emphysematous pyelonephritis is quite rare and careful evaluation is required. Prompt intervention is life saving and obviates the need for nephrectomy.

Bilateral simultaneous RIRS for calculus anuria in a 4 months male baby.

Treatment of pediatric stone disease is a challenge, more so, in the case of infants. Infantile anuria due to calculus disease is rare, as pre-renal causes predominate. Retrograde intrarenal surgery is a less often sorted modality in infants, due to the lingering skepticism regarding handling pediatric ureters and urethra. We hereby present the first case report of bilateral simultaneous RIRS, in a 4 month old male child. With better stone free rates than ESWL and a lesser incidence of major complications, we opted for RIRS in this child, taking advantage of the pre-stented ureter.