Sodium-glucose cotranspor ter 2 (SGLT2) inhibitors in nephrolithiasis: should we "gliflozin" patients with kidney stone disease? / Inibidores de cotransportadores sódio-glicose-2 (SGLT2) na nefrolitíase - devemos "gliflozinar" os litiásicos?

ABSTRACT The prevalence of nephrolithiasis is increasing worldwide. Despite advances in understanding the pathogenesis of lithiasis, few studies have demonstrated that specific clinical interventions reduce the recurrence of nephrolithiasis. The aim of this review is to analyze the current data and potential effects of iSGLT2 in lithogenesis and try to answer the question: Should we also "gliflozin" our patients with kidney stone disease?

RESUMO A prevalência da nefrolitíase está aumentando em todo o mundo. Apesar dos avanços na compreensão da patogênese da doença litiásica, poucos estudos demonstraram que intervenções clínicas específicas diminuem a recorrência da nefrolitíase. O objetivo desta revisão é analisar os dados atuais e efeitos potenciais dos iSGLT2 na doença litiásica e tentar responder à pergunta: devemos também "gliflozinar" os litiásicos?

Evaluating the Safety of Retrograde Intrarenal Surgery (RIRS): Intra- and Early Postoperative Complications in Patients Enrolled in the Global Multicentre Flexible Ureteroscopy Outcome Registry (FLEXOR).

PURPOSE: To assess the incidence of the most common intra- and early postoperative complications following RIRS in a large series of patients with kidney stones. METHODS: We conducted a retrospective analysis of patients with kidney stones who underwent RIRS across 21 centers from January 2018 to August 2021, as part of the Global Multicenter Flexible Ureteroscopy Outcome (FLEXOR) Registry. RESULTS: Among 6669 patients undergoing RIRS, 4.5% experienced intraoperative pelvicalyceal system bleeding without necessitating blood transfusion. Only 0.1% of patients, required a blood transfusion. The second most frequent intraoperative complication was ureteric injury due to the ureteral access sheath requiring stenting (1.8% of patients). Postoperatively, the most prevalent early complications were fever/infections requiring antibiotics (6.3%), blood transfusions (5.5%), and sepsis necessitating intensive care unit admission (1.3%). In cases of ureteric injury, a notably higher percentage of patients exhibited multiple stones and stone(s) in the lower pole, and these cases were correlated with prolonged lasing and overall surgical time. Hematuria requiring a blood transfusion was associated with an increased prevalence of larger median maximum stone diameters, particularly among patients with stones exceeding 20 mm. Furthermore, these cases exhibited a significant prolongation in surgical time. Sepsis necessitating admission to the intensive care unit was more prevalent among the elderly, concomitant with a significantly larger median maximum stone diameter. CONCLUSIONS: Our analysis showed that RIRS has a good safety profile but bleeding requiring transfusions, ureteric injury, fever, and sepsis are still the most common complications despite advancements in technology.

Retrograde intrarenal surgery using the ILY robotic flexible ureteroscope: a single centre experience.

Introduction: The ILY robotic flexible ureteroscope has been introduced in order to improve intraoperative ergonomics, reduce operator distance from radiation and shorten the learning curve. In this study we aimed to assess the clinical performance and feasibility of the ILY robot during retrograde intrarenal surgery (RIRS) and combined endoscopic procedures (miniECIRS). Material and methods: The RIRS procedures were performed using the ILY robotic arm in 57 adult patients (46 RIRS and 11 miniECIRS) from 2022 to 2023. All procedures were performed in the supine position. Pre-stenting was not the standard of care. Results: Turning on and calibration of the device took approximately 100 s. Average draping time was 93 s using original ILY drapes and 47 s using classic drapes designed for C-arm covering. Mean docking time was 73 s in procedures with ureteral access sheath (UAS) and 61 s in procedures without it. The undocking took less than 60 s in every case. Average procedure time was 63 min for RIRS and 55 min for miniECIRS. Endoscopically proven stone-free rate was achieved in 37 (80.4%) RIRS and 10 (90.9%) miniECIRS patients. A total of 17 (36.9%) RIRS and 8 (72.7%) miniECIRS procedures required conversion in order to perform basketing and stone fragments retrieval/transposition. Conclusions: The use of ILY robot during endourological procedures is feasible and urologists that are familiar with the device controller do not require extensive training. The time needed for device draping, docking and undocking was approximately 4 minutes. Moreover, use of the robot resulted in satisfactory stone-free rates.

Percutaneous Nephrolithotomy for De Novo Urolithiasis After Kidney Transplantation: A Systematic Review of the Literature.

Introduction and Objective: Renal transplantation is the treatment for end-stage renal disease that offers better quality of life and survival. Among the possible complications that might affect allografts, urolithiasis might have severe consequences, causing acute kidney injury (AKI) or septic events in immunocompromised patients. Allograft stones might be treated with percutaneous nephrolithotomy (PCNL). The aim of this Cochrane style review was to assess the safety and efficacy of PCNL in patients with renal transplant. Methods: A comprehensive search in the literature was performed including articles between July 1982 and June 2023, with only English original articles selected for this review. Results: The final review encompassed nine articles (108 patients). The mean age was 46.4 ± 8.7 years, with a male:female ratio of 54:44. The average time from transplantation to urolithiasis onset was 47.54 ± 23.9 months. Predominant symptoms upon presentation were AKI (32.3%), followed by urinary tract infection and fever (24.2%), and oliguria (12.9%). The mean stone size was 20.1 ± 7.3 mm, with stones located in the calices or pelvis (41%), ureteropelvic junction (23.1%), or proximal ureter (28.2%). PCNL (22F-30F) was more frequently performed than mini-PCNLs (16F-20F) (52.4% vs 47.6%). Puncture was guided by ultrasound (42.9%), fluoroscopy (14.3%), or both (42.9%). The stone-free rate (SFR) and complication rates were 92.95% (range: 77%-100%) and 5.5%, respectively, with only one major complication reported. Postoperatively, a ureteral stent and nephrostomy were commonly placed in 47%, with four patients needing a second look PCNL. During an average follow-up of 32.5 months, the recurrence rate was 3.7% (4/108), and the mean creatinine level was 1.37 ± 0.28 mg/dL. Conclusions: PCNL remains a safe and effective option in de novo allograft urolithiasis, allowing to treat large stones in one-step surgery. A good SFR is achieved with a low risk of minor complications. These patients should be treated in an endourology center in conjunction with the renal or transplant team.

Real-World Effectiveness of Preventive Pharmacological Therapy in Patients With Urolithiasis: A Retrospective Cohort Study.

RATIONALE & OBJECTIVE: Data supporting the efficacy of preventive pharmacological therapy (PPT) to reduce urolithiasis recurrence are based on clinical trials with composite outcomes that incorporate imaging findings and which have uncertain clinical significance. This study sought to evaluate if the use of PPT leads to fewer symptomatic stone events. STUDY DESIGN: Retrospective cohort study. SETTING: & Participants: Medicare enrollees with urolithiasis who completed 24-hour urine collections that revealed hypercalciuria, hypocitraturia, low urine pH, or hyperuricosuria. EXPOSURE: PPT (thiazide diuretics for hypercalciuria, alkali for hypocitraturia or low urine pH, or uric acid lowering drugs for hyperuricosuria) categorized as, 1) adherent to guideline-concordant PPT, 2) nonadherent to guideline-concordant PPT, or 3) untreated. OUTCOME: Symptomatic stone event occurrence (emergency department [ED] visit or hospitalization for urolithiasis or stone-directed surgery). ANALYTICAL APPROACH: Cox proportional hazards regression. RESULTS: Among 13,942 patients, 31.0% were prescribed PPT. Compared to no treatment, concordant/adherent PPT use was associated with a significantly lower hazard of symptomatic stone events for patients with hypercalciuria (hazard ratio [HR], 0.736 [95% confidence interval (CI), 0.593 to 0.915]) and low urine pH (HR, 0.804 [CI, 0.650 to 0.996]) but not for patients with hypocitraturia or hyperuricosuria. These associations were largely driven by significantly lower rates of ED visits after initiating PPT among the concordant/adherent group versus untreated patients. Patients with hypercalciuria had adjusted two-year predicted probabilities of a visit of 3.8% [95% CI, 2.5% to 5.2%%] and 6.9% [95% CI, 6.0% to 7.7%] for the concordant/adherent PPT and no-treatment groups, respectively. Among patients with low urine pH, these probabilities were 4.3% [95% CI, 2.9% to 5.7%] and 7.3% [95% CI, 6.5% to 8.0%] for the concordant/adherent PPT and no-treatment groups, respectively. LIMITATIONS: Potential bias from the possibility that patients prescribed PPT had more severe disease than untreated patients. CONCLUSION: Patients with urolithiasis and hypercalciuria who were adherent to treatment with thiazide diuretics as well as those with low urine pH adherent to prescribed alkali therapy had fewer symptomatic stone events than untreated patients.

First prospective clinical assessment of the ILY® robotic flexible ureteroscopy platform.

PURPOSE: To present the initial prospective clinical assessment of the ILY® robotic ureteroscopy manipulator platform, focusing on its safety and effectiveness. METHODS AND MATERIALS: Data gathered from 31 kidney units which underwent elective robotic flexible ureteroscopy (FURS) for renal stone management utilizing the ILY® robotic system. Patient demographics, stone characteristics, surgical durations, perioperative and post-operative complications, and follow-up parameters were collected. Our primary outcome was evaluating the efficacy and safety of the ILY® robotic ureteroscopy for treating kidney stones. Therefore, we analyzed complication rates, surgical durations, and the stone-free rate during follow-up. RESULTS: Our cohort consisted of 29 patients, presenting with 45 stones with a median volume of 736.22 mm3. The median operation time was 85 min, accompanied by 3 min for robot draping, 3.5 min for robot docking, 48 min of console operation, and lasing time of 36.75 min. Post operative stay for all patients was 1 day, while complications were observed in 9.68% of cases. Notably, all complications were classified as CVD (Clavien-Dindo) class 1 due to pain requiring emergency department visit. The stone-free rate achieved was 93.55%, and none of the patient required reoperation for the treated stone. CONCLUSION: In the first prospective clinical experience of the ILY® robotic FURS, we demonstrated its efficacy and safety. To further investigate its clinical practical value, additional investigations are warranted, including direct comparative analyses with manual flexible ureteroscopy techniques.

[Imaging in nephroureterolithasis]. / Bildgebung bei Nephroureterolithiasis.

In the acute diagnostics of a suspected nephroureterolithiasis, ultrasonography should be the examination modality of choice. In cases of suspected urolithiasis, unclear flank pain with fever or in cases of a solitary kidney, a noncontrast computed tomography (CT) scan should always subsequently be performed. If the sonography findings are inconclusive in pregnant women a magnetic resonance imaging (MRI) examination can be considered. If there are indications for urinary diversion, a retrograde imaging study should be performed as part of the urinary diversion. This or CT imaging is also suitable for preinterventional imaging before shock wave lithotripsy, percutaneous nephrolithotomy or ureteroscopy. Postinterventional imaging is not always necessary and sonography is often sufficient. In a conservative treatment approach an abdominal plain X­ray can be used for follow-up assessment.

Safety and Efficacy of "Dusting and Pop-Dusting" with High-Power Laser for Treatment of Large Pediatric Stones with Ureteroscopy and Lasertripsy: Prospective Outcomes from a University Teaching Hospital.

Introduction: The wide use of high-power laser has changed the landscape of ureteroscopy and lasertripsy (URSL). We wanted to look at the role and outcomes of high-power holmium:yttrium-aluminum-garnet laser for URSL in pediatric stone disease. Methods: A prospective analysis of consecutive pediatric patients treated with "Dusting and Pop-dusting" using a high-power laser was done between January 2016 and March 2022. The project was registered with our audit committee. Data were analyzed for patient demographics, stone characteristics, operative details, procedural outcomes, and complications. Stone-free rate (SFR) was defined as fragments ≤2 mm on postoperative ultrasound imaging 2-3 months after the procedure. Results: A total of 35 patients underwent 43 procedures (1.2 procedure/patient) during the study period with a mean age of 9.4 years (range 1-16 years) and a male:female ratio of 13:22. The stone location was in the kidney in 32 (91.4%) patients of which 8 were in multiple renal locations. The mean stone size was 18 mm (range 10-39 mm), with the pre- and post-stent rates of 37% and 56%, respectively. An access sheath was used in 19 (44%) procedures. The overall SFR on ultrasound scan was 94% (n = 33) with no procedural complications noted in our series and a mean length of stay of 0.9 days. Conclusion: Pediatric URSL using a high-power laser achieves a high SFR even for large and multiple renal stones with no complications noted in our prospective series. Parents must, however, be counseled about the need for staged procedures, which might be needed for large stones.

Comparing Balloon Dilation to Non-Balloon Dilation for Access in Ultrasound-Guided Percutaneous Nephrolithotomy: A Systematic Review and Meta-Analysis.

PURPOSE: This study aims to evaluate the safety and efficacy of ultrasound-guided balloon dilation compared to non-balloon dilation for percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: A systematic review and meta-analysis were conducted by searching PubMed, EMBASE, and the Cochrane Library. Results were filtered using predefined inclusion and exclusion criteria as described and meta-analysis was performed using Review Manager 5.4 software. RESULTS: A total of six studies involving 1189 patients who underwent PCNL were included. The meta-analysis results demonstrated that compared to non-balloon dilation, balloon dilation was associated with reduced haemoglobin drop [mean difference (MD) = -0.26, 95% CI = -0.40 ~ -0.12, P = 0.0002], decreased transfusion rate [odds ratio (OR) = 0.47, 95% CI = 0.24 ~ 0.92, P = 0.03], shorter tract establishment time (MD = -1.30, 95% CI = -1.87 ~ -0.72, P < 0.0001) and shorter operation time (MD = -5.23, 95% CI = -10.19 ~ -0.27, P = 0.04). CONCLUSIONS: Overall, ultrasound-guided balloon dilatation offered several advantages in PCNL procedures. It facilitated faster access establishment, as evidenced by shorter access creation time. Additionally, it reduced the risk of kidney injury by minimizing postoperative haemoglobin drop and decreasing the need for transfusions. Moreover, it enhanced the efficiency of surgery by reducing the operation time. However, it is important to note that the quality of some included studies was subpar, as they did not adequately control for confounding factors that may affect the outcomes. Therefore, further research is necessary to validate and strengthen these findings.

Vacuum-assisted Mini-percutaneous Nephrolithotomy for 2-3-cm Renal Stones: A Comparative Study with Retrograde Intra-renal Surgery.

PURPOSE: To compare vacuum-assisted percutaneous nephrolithotomy (VAmini-PCNL) with retrograde intra-renal surgery (RIRS) for the treatment of renal stones measuring 2-3 cm in diameter. MATERIAL AND METHODS: This retrospective study included children receiving treatment for pyelocalyceal stones of 2-3 cm in diameter from November 2018 to September 2022. Consecutive patients undergoing VAmini-PCNL after 2020 were compared with a historically matched group undergoing RIRS. VAmini-PCNL was performed using a 12-Ch nephroscope through a 16-Ch vacuum ClearPetra access sheet. RIRS was performed using a flexible ureteroscope through a ureteral sheath. The endpoints included the need for pre-stenting, duration of surgery, complications, stone-free rate (SFR), and need for secondary procedures. RESULTS: The patients were grouped into two with 15 patients for each group. VAmini-PCNL group was not different from the RIRS one for age at surgery [median (range) 6.6 (1-12)years vs. 7.7 (1.5-14)years], and stone diameter [median (range) 2.4 (2.0-2.9)cm vs. 2.3 (2.1-2.8)cm] and density [median (range) 577.5 (421-1068) vs. 541.5 (462-927) Hunsfield Units]. Pre-stenting was necessary in five RIRS patients (33 %). The median duration of surgery was 85.3 (76-112)min for VAmini-PCNL vs. 150.6 (132-167)min for RIRS, p = 0.00001. No major complications were observed. The SFR was 100 % after VAmini-PCNL and 60 % after RIRS, p = 0.02. All residual fragments were removed with a second RIRS. CONCLUSION: VAmini-PCNL was feasible and safe in children aged >1 year. It allowed for a significantly higher SFR despite a significantly shorter operative time than RIRS, which also requires pre-stenting in one-third of patients and a second RIRS in 40 % of cases. LEVEL OF EVIDENCE: III.

Has fluoroless endourology (URS and PCNL) come of age? Evidence from a comprehensive literature review.

INTRODUCTION: Radiation via the use of imaging is a key tool in management of kidney stones. Simple measures are largely taken by the endourologists to implement the 'As Low As Reasonably Achievable' (ALARA) principle, including the use of fluoroless technique. We performed a scoping literature review to investigate the success and safety of fluoroless ureteroscopy (URS) or percutaneous nephrolithotomy (PCNL) procedures for the treatment of KSD. METHODS: A literature review was performed searching bibliographic databases PubMed, EMBASE and Cochrane library, and 14 full papers were included in the review in accordance with the PRISMA guidelines. RESULTS: Of the 2535 total procedures analysed, 823 were fluoroless URS vs. 556 fluoroscopic URS; and 734 fluoroless PCNL vs. 277 fluoroscopic PCNL. The SFR for fluoroless vs. fluoroscopic guided URS was 85.3% and 77%, respectively (p=0.2), while for fluoroless PCNL vs. fluoroscopic group was 83.8% and 84.6%, respectively (p=0.9). The overall Clavien-Dindo I/II and III/IV complications for fluoroless and fluoroscopic guided procedures were 3.1% (n=71) and 8.5% (n=131), and 1.7% (n=23) and 3% (n=47) respectively. Only 5 studies reported a failure of the fluoroscopic approach with a total of 30 (1.3%) failed procedures. CONCLUSION: The ALARA protocol has been implemented in endourology in numerous ways to protect both patients and healthcare workers during recent years. Fluoroless procedures for treatment of KSD are safe and effective with outcomes comparable to standard procedures and could become the new frontier of endourology in selected cases.

Failed insertion of ureteral access sheath during flexible ureterorenoscopy: a randomized controlled trial comparing second session flexible ureterorenoscopy or same session mini percutaneous nephrolithotomy.

PURPOSE: To compare different treatment approaches in patients with failed ureteral access sheath placement during first flexible ureterorenoscopy (f-URS) session. METHODS: Patients with kidney stones measuring 1-2 cm, presented to our urology clinic between September 2020 and September 2021, were included in the study for evaluation. The study was designed prospectively (Clinical-Trials number NCT05911945). Patients were randomized into two groups, in case of a failed ureteral access sheath placement during the first f-URS session. In group 1, JJ stent was placed for dilation and second session of f-URS was planned. In group 2, mini percutaneous nephrolithotomy (mPNL) was performed in the same session. RESULTS: Twenty-four patients were included in each group. Pre-operative demographic data and stone characteristics of the patients in each group were comparable. Operation time, fluoroscopy time, and hospital stay were significantly higher in the mini-PNL group. When SF-36 values were compared, physical function, pain, role limitation, and general health value scores were improved in both groups after treatment. The improvement in physical function and pain parameters was statistically significant in the mPNL group. In patients with failed ureteral access sheath placement, placing a JJ stent for dilation and postponing f-URS for 4-6 weeks provides the advantages of low hospitalization time for each admission, shorter fluoroscopy and operation time. CONCLUSIONS: Performing mPNL in the same session, results in better improvements in SF-36 parameters such as pain and physical function compared to f-URS. The success and complication rates of the two procedures were comparable.

Influence of tract location on the outcomes of endoscopic combined intrarenal surgery: A retrospective analysis of 1000 cases.

OBJECTIVES: This study aimed to investigate the influence of tract location on surgical outcomes in endoscopic combined intrarenal surgery (ECIRS), considering the location of residual stones. METHODS: From January 2015 to December 2021, 1417 consecutive patients underwent ECIRS in three hospitals. After excluding patients with preoperative percutaneous nephrostomy, intended multi-stage procedures, those with a tract in the renal pelvis, and those with multiple tracts, 1000 patients were retrospectively analysed by comparing three groups based on tract location: group 1 (upper calyx), group 2 (middle calyx), and group 3 (lower calyx). A multivariate logistic regression model was implemented to assess whether the tract location independently affected the stone-free status. RESULTS: Patient characteristics were significantly different among the groups in terms of age, stone laterality, presence of calyceal stones, and hydronephrosis. There were no differences in stone-free rate (SFR) among the three groups. Multivariate analysis indicated that the tract location (group 1 or 2 compared with group 3) did not significantly affect the stone-free status (odds ratio = 1.4, 0.9-1.9, p = 0.066). Surgical duration significantly varied among the groups, with the shortest time observed in group 1. Organ injury was observed exclusively in group 1 (1.13%). Residual fragments were predominantly found in the lower calyx, with the calyx associated with the tract being the second most common location. CONCLUSIONS: Tract location does not significantly affect SFR. To improve the SFR, observation of the lower calyx and tract placement is important.

Is Stent on a String the New Gold Standard for Postureteroscopy Ureteral Drainage? Evidence from a Systematic Review.

Introduction: Ureteral stents are widely used throughout urologic surgery, most commonly following ureteroscope (URS) procedures. This systematic review aims to assess the current evidence concerning stent on string (SOS) placed after URS and compare it with stents without strings (SWOSs). Methods: A systematic review was conducted on several databases using the preferred reporting items for systematic review and meta-analysis (PRISMA) methodology for studies in English language, for patients of all age groups, who had an SOS after URS for stone disease. Results: Of 1210 records identified, a total of 22 studies (20 adult and 2 pediatric studies) were included, with a total of 8382 patients. Of these, 3427 (40.9%) had SOSs inserted and 434 (11%) were in the pediatric age group. Our results show that SOS provides several advantages, and compared with SWOS, they were in situ for less time, with no difference in complications such as urinary tract infection or urinary symptoms. Furthermore, significant cost savings, less pain on removal, and high rates of safe home removal were reported in SOS, with >90% patients reporting that they would be happy to remove their SOSs at home. However, a small risk of stent dislodgment must be considered when making decisions regarding SOS placement after URS. Conclusion: SOS provides an excellent option after URS, especially in those patients with no intraoperative complication, and their placement is done as a routine insertion based on surgeon preference. These stents reduce dwell time, pain, cost, risks, and suffering involved from prolonged stenting, and majority of patients are happy to remove it themselves at home. Although their use seems to be still restricted in the current endourology practices, they are likely to become the new gold standard for routine URS in future, with more shared decision making and patient-reported outcome measures coming into the mainstream.

Advances in lasers for the minimally invasive treatment of upper and lower urinary tract conditions: a systematic review.

PURPOSE: Technological advancements in laser lithotripsy are expanding into numerous fields of urology, like ureteroscopy (URS), percutaneous nephrolithotomy (PCNL), and benign and malignant soft-tissue treatments. Since the amount of research regarding lasers in urology has grown exponentially, we present a systematic review of the most recent and relevant advances encompassing all lasers used in urological endoscopic treatment. METHODS: We performed a literature search using PubMed (May 2023) to obtain information about lasers for urological purposes. We included only recent data from published articles between 2021 and 2023 or articles ahead of print. RESULTS: Lasers are widely used in lithotripsy for ureteric, renal, and bladder stones, benign prostate surgery, and bladder and upper tract tumor ablation. While the holmium (Ho:YAG) laser is still predominant, there seems to be more emphasis on pulse modulation and newer lasers such as thulium fiber laser (TFL) and pulsed Tm:YAG laser. CONCLUSION: The use of lasers and related technological innovations have shown increasing versatility, and over time have proven to be invaluable in the management of stone lithotripsy, treatment of benign and malignant prostate diseases, and urothelial tumors. Laser endoscopic treatment is heavily based on technological nuances, and it is essential to know at least the basics of these technologies. Ultimately the choice of laser used depends on its availability, cost, surgeon experience and expertise.

Outcomes of Flexible Ureteroscopy vs Extracorporeal Shock Wave Lithotripsy for Renal Stones in Pediatric Patients: A European Association of Urology Urolithiasis Guidelines Systematic Review and Meta-Analysis.

PURPOSE: We sought to determine which treatment between flexible ureteroscopy and shock wave lithotripsy has a better stone-free rate in pediatric patients (<18 years) with renal or proximal ureteric stones (<2 cm). Subanalysis for all outcomes for randomized controlled trials only. MATERIALS AND METHODS: Using PubMed, Web of Science, and the Cochrane database, we identified studies (randomized clinical trials and prospective comparative nonrandomized studies) published until August 2022 reporting surgical outcomes of pediatrics patients undergoing flexible ureteroscopy and shock wave lithotripsy with renal or proximal ureteric stones <2 cm (PROSPERO ID: CRD42022378790). Only randomized controlled trials were considered for meta-analysis. Stone-free rate, operative time, and complications were analyzed. Analysis was performed in R. RESULTS: A total of 6 studies identified, of which 3 were randomized clinical trials and 4 had data on renal stones. A total of 669 patients were analyzed. Mean age ranged from 4.4 to 12.4 years. The shock wave lithotripsy group presented a range of stone-free rate between 21 and 90% while the flexible ureteroscopy group presented a range of stone-free rates between 37% and 97%. Meta-analysis of randomized controlled trials only (n=302) demonstrated significantly higher stone-free rate in flexible ureteroscopy vs shock wave lithotripsy (RR = 1.17, 95% CI: 1.04-1.33, P = 0.01), operative time (mean difference = +16.4 minutes, 95% CI: 7.3-25.5, P < 0.01) and hospital stay (mean difference = +0.25 days, 95% CI: 0.14-0.36, P < 0.001). But no difference in fluoroscopy exposure time (mean difference = -21.0 seconds, 95% CI: -42.6 to 0.56, P = 0.07), Clavien I-II (RR = 1.23, 95% CI: 0.71-2.12, P = 0.45) or Clavien III-V complications (RR = 1.04, 95% CI: 0.32-3.42, P = 0.95). CONCLUSIONS: Flexible ureteroscopy has a significantly higher stone-free rate than shock wave lithotripsy, with no difference in complication rate or fluoroscopy exposure time, and significantly higher operative times and hospital stay. However, the current evidence base for this is weak and further randomized trials are needed.

Does unenhanced computerized tomography as imaging standard post-retrograde intrarenal surgery paradoxically reduce stone-free rate and increase additional treatment for residual fragments? Outcomes from 5395 patients in the FLEXOR study by the TOWER group.

Background: Assessment of residual fragments (RFs) is a key step after treatment of kidney stones. Objective: To evaluate differences in RFs estimation based on unenhanced computerized tomography (CT) versus X-rays/ultrasound after retrograde intrarenal surgery (RIRS) for kidney stones. Design: A retrospective analysis of data from 20 centers of adult patients who had RIRS was done (January 2018-August 2021). Methods: Exclusion criteria: ureteric stones, anomalous kidneys, bilateral renal stones. Patients were divided into two groups (group 1: CT; group 2: plain X-rays or combination of X-rays/ultrasound within 3 months after RIRS). Clinically significant RFs (CSRFs) were considered RFs ⩾ 4 mm. One-to-one propensity score matching for age, gender, and stone characteristics was performed. Multivariable logistic regression analysis was performed to evaluate independent predictors of CSRFs. Results: A total of 5395 patients were included (1748 in group 1; 3647 in group 2). After matching, 608 patients from each group with comparable baseline and stone characteristics were included. CSRFs were diagnosed in 1132 patients in the overall cohort (21.0%). Post-operative CT reported a significantly higher number of patients with RFs ⩾ 4 mm, before (35.7% versus 13.9%, p < 0.001) and after matching (43.1% versus 23.9%, p < 0.001). Only 21.8% of patients in the matched cohort had an ancillary procedure post-RIRS which was significantly higher in group 1 (74.8% versus 47.6%, p < 0.001). Age [OR 1.015 95% confidence interval (CI) 1.009-1.020, p < 0.001], stone size (OR 1.028 95% CI 1.017-1.040, p < 0.001), multiple stones (OR 1.171 95% CI 1.025-1.339, p = 0.021), lower pole stone (OR 1.853 95% CI 1.557-2.204, p < 0.001) and the use of post-operative CT scan (OR 5.9883 95% CI 5.094-7.037, p < 0.001) had significantly higher odds of having CSRFs. Conclusions: CT is the only reliable imaging to assess the burden of RFs following RIRS and urologist should consider at least one CT scan to determine the same and definitely plan reintervention only based on CT rather than ultrasound and X-ray combination.

Effect of a high-citrate beverage on urine chemistry in patients with calcium kidney stones.

A well-accepted strategy to prevent kidney stones is to increase urine volume by increasing oral intake of fluids, especially water, to lower supersaturation of the relevant, relatively insoluble salts, and thereby lower the risk of precipitation. Randomized controlled trials have shown that this strategy works. It is inexpensive, safe, and intuitively attractive to patients. However, although any beverage can increase urine volume, and citrus juices can increase urine citrate content and pH, no beverage other than water has been clearly shown by randomized controlled trial to prevent kidney stones. We designed an innovative, palatable, low-calorie, high alkali citrate beverage to prevent kidney stones, called Moonstone. One packet of Moonstone powder, mixed in 500 ml of water, contains 24.5 meq of alkali citrate. We administered one packet twice a day to ten calcium stone formers. Moonstone resulted in an increase in mean 24-h urine citrate and urine pH, and a decrease in supersaturation of calcium oxalate in calcium stone formers compared to an equal volume of water. These changes, comparable to those seen in a prior study of a similar amount of (potassium-magnesium) citrate, will likely be associated with a clinically meaningful reduction in kidney stone burden in patients with calcium stones. The effect to increase urine pH would also be expected to benefit patients with uric acid and cystine stones, groups that we hope to study in a subsequent study. The study preparation was well tolerated and was selected as a preferred preventative strategy by about half the participants. Moonstone is an alternative, over-the-counter therapy for kidney stone prevention.

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.

Technical Aspects and Clinical Outcomes of Robotic Ureteroscopy: Is It Ready for Primetime?

PURPOSE OF REVIEW: Robotic surgery in urology has already been widely employed in robotic-assisted laparoscopic surgery for minimally invasive procedures (MIS). We wanted to analyse rapidly developing robotic ureteroscopy (RoboURS) for the treatment of renal stone disease. RECENT FINDINGS: A comprehensive literature review was performed for technical aspects and clinical outcomes of RoboURS. RoboURS has made significant breakthroughs with each model proving that this technology improves ergonomics and supports surgeon and instrument longevity while minimising musculoskeletal issues in retrograde intra-renal surgery (RIRS). Further randomised controlled trials are required to compare the efficacy of RoboURS vs manual flexible ureteroscopy (FURS). The cost-effectiveness will also need to be assessed prior to widespread acceptance into urological infrastructure and mainstream practice. RoboURS continues to evolve despite the limitations of infrastructure and cost-effectiveness. It holds the promise of a better future for surgeon longevity, reduced peri-operative morbidity and better workplace environment.