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Objective: Urinary tract infection (UTI) is a common complication after ureteroscopy. Despite sterilization, there is evidence that reusable ureteroscopes can still harbor bacteria. Whether this property is associated with increased risk of UTI is unknown. The objective of this study was to compare rates of postoperative UTI after ureteroscopy for urolithiasis performed with single-use ureteroscopes vs reusable ureteroscopes. Materials and Methods: This was a single-center, retrospective cohort study of all patients who underwent ureteroscopy for urolithiasis between June 2012 and March 2021. Outcomes were compared between those who underwent stone removal with single-use and reusable ureteroscopes. The primary endpoint was postoperative UTI. The secondary endpoints were intra-operative and postoperative outcomes, and health service utilization after surgery. Results: Of 991 patients identified, 500 (50.4%) underwent ureteroscopy with a single-use ureteroscope. Rates of postoperative UTI were lower in those undergoing ureteroscopic stone removal with a single-use ureteroscope compared to a reusable ureteroscope (6.5% vs 11.9%, p = 0.018). In multivariable analysis, use of a single-use ureteroscope was associated with lower odds of postoperative UTI compared to a reusable ureteroscope when adjusting for risk (odds ratio 0.37, p = 0.015). Use of a single-use ureteroscope was associated with a higher stone clearance rate compared to a reusable ureteroscope (90.0% vs 83.9%, p = 0.005). There was no difference in operative time, overall complication rate, readmission, or emergency department visits between two groups. Conclusion: Single-use ureteroscopes are associated with a twofold decreased risk of UTI and increased stone clearance rate after ureteroscopy for urolithiasis compared to reusable ureteroscopes.

Introduction. Intrahepatic lithiasis (IHL) is a disease that occurs in middle-aged and elderly people. Presentations of IHL in the young are rare, and considerations in the differential diagnosis include primary sclerosing cholangitis, recurrent pyogenic cholangitis, bile acid transporter defect, Caroli's disease, and other known genetic diseases. Treatment is often complex, all in order to prevent complications. In this report, we describe the diagnosis and treatment, with the application of a flexible ureteroscope of 4 Fr, of a younger patient with intrahepatic lithiasis. Case report. A 25-year-old man appeared with a known diagnosis of IHL and a recurrent attack of abdominal pain that required medical treatment. Magnetic resonance imaging of the abdomen showed segmental stenosis of the left bile duct and segmental bile duct for the lateral section with intraductal calculi and its proximal dilatation and mild dilatation of the bile ducts for liver segments II and III. During surgery, a cholangiography and ultrasonography of the liver were performed. Through choledochotomy, the bile ducts were flushed, and extirpation of the several calculi was performed. The bile ducts were examined with a chole-dochscope, and the remaining concrements were removed with a flexible ureteroscope. Conclusion. Segmental liver bile ducts may be explored with a flexible ureteroscope without bile duct injury or trauma. In selected cases, with isolated lithiasis in one liver lobe and the absence of concomitant diseases, IHL can be treated surgically without liver resection. This case is unique because we did not perform liver resection but duct stone extraction, which was an appropriate treatment since there was no recurrence during the two-year follow-ups. [ABSTRACT FROM AUTHOR]

At present, endoscopic retrograde cholangiopancreatography (ERCP) and T－tube sinus tract lithotomy are the main treatment methods for residual choledocholithiasis after surgery. However, these treatment methods have certain drawbacks； for example, ERCP may cause complications such as postoperative pancreatitis, bleeding, and perforation, and T－tube sinus tract lithotomy may cause sinus tract injury and bleeding. As a commonly used instrument in urology, flexible ureteroscope has the characteristics of small diameter and flexible angle and thus has a good prospect in the treatment of common bile duct stones. A patient with common bile duct stones was successfully treated by flexible ureteroscopy combined with a stone basket in Department of General Surgery, The Second People’s Hospital of Guizhou Province. Up to now, the patient has been followed up for seven months with no special discomfort, and magnetic resonance cholangiopancreatography showed no common bile duct stones. [ABSTRACT FROM AUTHOR]

PurposeHigh intra-renal pressures during flexible ureteroscopy have been associated with adverse renal tissue changes as well as pyelovenous backflow. Our objective was to investigate the effect of various intra-renal pressures on histologic changes and fluid extravasation during simulated ureteroscopy.Materials and methodsTwenty-four juvenile pig kidneys with intact ureters were cannulated with an Olympus flexible ureteroscope with and without a ureteral access sheath and subjected to India ink-infused saline irrigation for 30 minutes at constant pressures ranging from sphygmomanometer settings of 50mm, 100mm and 200mmHg. Renal tissue samples were collected, processed and stained, and were evaluated by a blinded pathologist for depth of ink penetration into renal parenchyma as a percentage of total parenchymal thickness from urothelium to renal capsule.ResultsThe mean percentage of tissue penetration for kidneys with ink present in the cortical tubules at sphygmomanometer pressure settings of 50, 100, and 200mm Hg without a ureteral access sheath was 33.1, 31.0 and 99.3%, respectively and with ureteral access sheath was 0, 0 and 18.8%, respectively. Overall, kidneys with an access sheath demonstrated a smaller mean tissue penetration among all pressure compared to kidneys without a sheath (6.3% vs. 54.5%, p=0.0354). Of kidneys with sheath placement, 11% demonstrated any ink compared to 56% of kidneys without sheath placement.ConclusionsPressurized endoscopic irrigation leads to significant extravasation of fluid into the renal parenchyma. Higher intra-renal pressures were associated with increased penetration of irrigant during ureteroscopy in an ex-vivo porcine model.

INTRODUCTION:Two automated irrigation systems have been released for use during endoscopic procedures such as ureteroscopy: the Cogentix RocaFlow® (CRF) and Thermedx FluidSmart® (TFS). Accurate pressure control using automated systems may help providers maintain irrigation pressures within a safe range while also providing clear visualization. Our objective was to directly compare these systems based on their pressure accuracy, pressure-flow relationships, and fluid heating capabilities in order to help providers better utilize the temperature and pressure settings of each system. MATERIALS AND METHODS:An in vitro ureteroscopy model was used for testing, consisting of a short semirigid ureteroscope (6/7, 5F, 31cm Wolf 425612) connected to a continuous digital pressure transducer (Meriam m1550). Each system pressure output and flow-rate, via 100mL beaker filling time, was measured using multiple trials at pressure settings between 30 and 300mmHg. Output fluid temperature was monitored using a digital thermometer (Omega DP25-TH). RESULTS:The pressure output of both systems exceeded the desired setting across the entire tested range, a difference of 15.7±2.4mmHg for the TFS compared to 5.2±1.5mmHg for the CRF (p < 0.0001). Related to this finding, the TFS also had slightly higher flow rates across all trials (7±2mL/min). Temperature testing revealed a similar maximum temperature of 34.0⁰C with both systems, however, the TFS peaked after only 8 minutes and started to plateau as early as 4-5 minutes into the test, while the CRF took over 18 minutes to reach a similar peak. CONCLUSIONS:Our in vitro ureteroscopy testing found that the CRF system had better pressure accuracy than the TFS system but with noticeably slower fluid heating capabilities. Each system provided steady irrigation at safe pressures within their expected operating parameters with small differences in performance that should not limit their ability to provide steady irrigation at safe pressures.

According to the guidelines, percutaneous nephrolithotomy is the main treatment for patients with kidney stones larger than 2 cm. However, many studies have recently been published describing the safety and efficacy of retrograde intrarenal surgery (RIRS) in the treatment of patients with kidney stones of similar size. This paper reviews the literature on the use of RIRS in the treatment of patients with kidney stones larger than 2 cm. The study aims to evaluate the safety and efficacy of RIRS in the treatment of kidney stones larger than 2 cm. Such indicators as the duration of surgical treatment, stone-free rate, intra- and postoperative complications were evaluated. Also, the history of the development of ureteroscopy as a diagnostic and therapeutic method for diseases of the upper urinary tract is briefly reviewed. The material was searched in the PubMed, Scopus, Web of Science, and Google Scholar databases.

Objective: Unusual or unexpected effect of treatment Background: The removal of concurrent ureteral and renal stones within a single procedure has always been a challenge for urological surgeons. The incorporation of single-use digital flexible ureteroscopes into laparoscopic ureterolithotomy procedures has demonstrated effective removal of concurrent stones with a good clearance rate and decreased risk of bleeding and trauma. We report the successful removal of a unilateral upper ureteral stone and a smaller renal stone with this procedure. Case Report: A 60-year-old man visited the outpatient clinic with an ultrasonography report that revealed a large proximal ureteral stone with moderate hydronephrosis, accompanied by bilateral renal stones and prostatic hyperplasia. He had been experiencing urinary urgency for a year and was determined to undergo lithotomy. Due to his longstanding history of coronary artery disease and myocardial ischemia, the urologists decided that concurrent stone removal within an operation would be the best treatment. A preoperative computed tomography urogram measured the left ureteral and renal stones to be 2.0×0.8 cm and 0.6 cm, respectively. Both stones were successfully removed by laparoscopic ureterolithotomy using a single-use digital flexible ureteroscope. The patient had an uneventful recovery and remained well 1 month post-operation. Conclusions: The application of single-use digital flexible ureteroscopes for laparoscopic ureterolithotomy has demonstrated safety, efficiency, and cost-effectiveness. The authors believe that it is a safe alternative for the removal of concurrent ureteral and renal stones, especially in patients with multiple comorbidities. [ABSTRACT FROM AUTHOR]

PurposeTo critically review all literature concerning the cost-effectiveness of flexible ureteroscopy comparing single-use with reusable scopes.Materials and methodsA systematic online literature review was performed in PubMed, Embase and Google Scholar databases. All factors potentially affecting surgical costs or clinical outcomes were considered. Prospective assessments, case control and case series studies were included.Results741 studies were found. Of those, 18 were duplicated and 77 were not related to urology procedures. Of the remaining 646 studies, 59 were considered of relevance and selected for further analysis. Stone free and complication rates were similar between single-use and reusable scopes. Operative time was in average 20% shorter with digital scopes, single-use or not. Reusable digital scopes seem to last longer than optic ones, though scope longevity is very variable worldwide. New scopes usually last four times more than refurbished ones and single-use ureterorenoscopes have good resilience throughout long cases. Longer scope longevity is achieved with Cidex and if a dedicated nurse takes care of the sterilization process. The main surgical factors that negatively impact device longevity are lower pole pathologies, large stone burden and non-use of a ureteral access sheath. We have built a comprehensive fi nancial costeffective decision model to fl exible ureteroscope acquisition.ConclusionsThe cost-effectiveness of a fl exible ureteroscopy program is dependent of several aspects. We have developed a equation to allow a literature-based and adaptable decision model to every interested stakeholder. Disposable devices are already a reality and will progressively become the standard as manufacturing price falls.

Context: The refined mechanics of a flexible ureteroscope (fURS) are vulnerable to damage. Sending the fURS for repair is costly and has driven interest toward estimating the resources used for fURS repairs. Objective: To systematically review available literature and to estimate the total weighted repair rate of an fURS and the average repair cost per ureteroscopy. Evidence acquisition: A systematic review was conducted by searching the MEDLINE, Embase, Web of Science, and Cochrane Library databases. The average costs of all repairs identified in the included studies were extracted. A random-effect model was used to calculate the pooled total fURS repair rate. The total weighted repair rate and average cost per repair were multiplied to provide an average cost of repair per ureteroscopy procedure. Evidence synthesis: We identified 18 studies that fulfilled the inclusion criteria, which included 411 repairs from 5900 investigated ureteroscopy procedures. The calculated weighted repair rate was 6.5% ± 0.745% (95% confidence interval: 5.0–7.9%; I2 = 75.3%), equivalent to 15 ureteroscopy procedures before repair. The average cost per repair was 6808 USD; according to the weighted repair rate of 6.5%, this corresponds to an average repair cost of 441 USD per procedure. Egger’s regression test did not reveal a significant publication bias (p = 0.07). Conclusions: This is the first meta-analysis to estimate the repair rate of the fURS used for ureteroscopy. Our analysis demonstrates a repair rate of 6.5%, equivalent to 15 ureteroscopy procedures between fURS repairs and a repair cost of 441 USD per procedure. Ureteroscopy practices should consider fURS breakage rates and repair costs to optimize the use of reusable versus disposable devices. Patient summary: We reviewed available literature investigating the repair rate of a flexible ureteroscope (fURS). We found that fURSs are sent for repair after every 15 ureteroscopy procedures, corresponding to 441 USD per procedure in repair cost.

Maintenance of flexible ureteroscopes can involve high costs and administrative burden. Instrument fragility necessitates eventual repair, rendering scopes inaccessible during refurbishment. We conducted a multi-institutional prospective cohort study to identify perioperative factors influencing flexible ureteroscope durability. Patients undergoing flexible ureteroscopy (URS) at six United States endourology centers were enrolled between August 2014 and June 2015. Surgeon self-reported concern and satisfaction with scope performance as well as upward and downward angles of deflection for each scope tip were measured before and after each procedure. The need for scope repair was determined by the operating surgeon at the time of the procedure and recorded. 424 URS cases using 74 flexible ureteroscopes were identified. Scope repair was required in 28 cases (6.6%) involving 26 scopes (35.1%). Upon univariate analysis, shorter patient height, absence of guidewire use, presence of a ureteral access sheath (UAS), longer procedure time, larger stone size, lithotrite type, surgeon training level, and self-reported concern were associated with scope repair. Upon multivariate analysis, UAS use (OR = 2.53, p = 0.005) and degree loss of scope upward flexion during a case (OR = 1.02, p = 0.03) increased the odds of a scope needing repair while the use of safety guidewire decreased the odds of a scope repair (OR = 0.50, p = 0.045). Lithotrite use and surgeon concern were associated with degree loss of scope upward flexion. The use of a UAS, absence of a safety guidewire, and the loss of upward ureteroscope flexion should be considered when evaluating means of optimizing reusable ureteroscope durability.

IntroductionUreteral access sheaths (UAS) facilitate flexible ureteroscopy in the treatment of urolithiasis. The physical properties of UAS vary by manufacturer and model. We compared three new UAS: Glideway (GW, Terumo, 11/13Fr, 12/14Fr), Pathway (PW, Terumo 12/14F) and Navigator HD (NHD, Boston Scientific, 11/13Fr, 12/14Fr) in the domains of safety characteristics, positioning characteristics, lubricity and radioopacity.Materials and methodsIn vitro testing of the three UAS included safety testing-tip perforation force, sheath edge deformation and dilator extraction forces. Positioning characteristics tested included tip bending, stiffness (resistance to coaxial buckling forces), kinking (resistance to perpendicular forces), and insertion forces. Lubricity was assessed by measured frictional forces of the outer sheath. Finally, radio-opacity was tested utilizing fluoroscopic imaging of the three 12F sheaths and inner dilators.ResultsThe PW (0.245 lb) and GW (0.286 lb) required less force for tip perforation compared to the NHD (0.628 lb). The NHD sheath edge deformation was mild compared to more severe deformation for the PW and GW. The PW (1.008 lb) required greater force than the GW (0.136 lb) and NHD (0.043 lb) for inner dilator removal. The GW (3.69 lbs) and NHD (4.17 lb) had similar inner dilator tip stiffness when bent, while the PW had the weakest inner dilator tip, 1.91 lbs. The PW (0.271 lb) was most susceptible to buckling and kinking (1.626 lb). The most lubricious UAS was the NHD (0.055 lbs for 12F). The NHD (0.277 lbs) required the least insertional force through a biological model and possessed the greatest radio-opacity.ConclusionsComparison of different commercially available UAS in various sizes reveals that there are mechanical differences in sheaths that may play a role clinically. The Terumo sheaths' (GW and PW) were outperformed by the Boston Scientific NHD in simulating safety, ease of use and radio-opacity.

INTRODUCTION:Reusable ureteroscope durability and need for repair are significant sources of expense and inefficiency for patients and urologists. Utilization of LithoVue™, a disposable flexible digital ureteroscope, may address some of these concerns. To identify its economic impact on clinical care, we performed a micro-cost comparison between flexible reusable fiberoptic ureteroscopes (URF-P6™) and LithoVue. PATIENTS AND METHODS:For this prospective, single-center micro-costing study, all consecutive ureteroscopies performed during 1 week each in July and August 2016 utilized either URF-P6 or LithoVue ureteroscopes respectively. Workflow data were collected, including intraoperative events, postoperative reprocessing cycle timing, consumables usage, and ureteroscope cost data. RESULTS:Intraoperative data analysis showed mean total operating room time for URF-P6 and LithoVue cases were 93.4 ± 32.3 and 73.6 ± 17.4 minutes, respectively (p = 0.093). Mean cost of operating room usage per case was calculated at $1618.72 ± 441.39 for URF-P6 and $1348.64 ± 237.40 for LithoVue based on institutional cost rates exclusive of disposables. Postoperative data analysis revealed costs of $107.27 for labor and consumables during reprocessing for URF-P6 cases. The costs of ureteroscope repair and capital acquisition for each URF-P6 case were $957.71 and $116.02, respectively. The total ureteroscope cost per case for URF-P6 and LithoVue were $2799.72 and $2852.29, respectively. CONCLUSIONS:Micro-cost analysis revealed that the cost of LithoVue acquisition is higher per case compared to reusable fiberoptic ureteroscopes, but savings are realized in labor, consumables, and repair. When accounting for these factors, the total cost per case utilizing these two ureteroscopes were comparable.

Background and Objectives: Disposable flexible ureteroscopes have been widely used because of their cost-effectiveness and higher sterility potential compared with reusable flexible ureteroscopes. This study aimed to compare the surgical outcomes and complication rates in patients who undergo reusable or disposable flexible ureteroscopic stone surgeries (fURS) for urinary stone disease. Materials and Methods: A systematic review and meta-analysis were conducted under the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. This systematic review was registered with PROSPERO (CRD42022331291). Clinical trials comparing reusable and disposable fURS for stone disease were found from PubMed, EMBASE, Cochrane Library, and the Web of Science up to March 2022. Participants were patients with upper urinary tract stones; the interventions were reusable or disposable fURS. Outcomes, including stone-free rate, operation time, length of hospital stay, and complication rate, were compared for analysis. Results: Overall, 111 studies were identified, but after removing duplicate studies, 75 studies remained. Thirty-two of these studies were excluded. Of the 43 screened studies, 11 met the eligibility criteria. There was no difference in the stone-free rate (SFR) between disposable and reusable fURS (p = 0.14; OR = 1.36; 95% CI, 0.9 to 2.04). For operation time, no difference was identified between reusable and disposable fURS groups (p = 0.12; MD = −5.31; 95% CI, −12.08 to 1.46). For hospital stay, there was also no difference between the two groups (p = 0.61; MD = −0.03; 95% CI, −0.17 to 0.10). There was no significant difference in complication rate between the two groups (p = 0.85; OR = 0.95; 95% CI, 0.56 to 1.61). Conclusions: There were no differences in the SFR, operation time, length of hospital stay, and complication rate between reusable and disposable fURS. Disposable fURS may be a comparable alternative to reusable fURS. [ABSTRACT FROM AUTHOR]

Objective To evaluate the efficacy and safety of flexible ureteroscopy for upper urinary tract calculi in children. Methods Between March 2015 to March 2021, clinical data were retrospectively reviewed for 215 children with upper urinary tract calculi undergoing flexible ureteroscopy. With a total of 239 involved sides, there were 141 boys and 74 girls with a mean age of 4.6 (1. 2 - 14.4) years. There were renal calculi (n = 179 ; bilateral n = 19) and upper ureteral calculi (n = 36 ; bilateral n = 5). The diameter of calculi ranged from 5 to 28 mm. All of them were diagnosed preoperatively by urinary tract ultrasonography, spiral computed tomography (CT) or intravenous urography imaging (IVP) without severe urinary tract anomalies. Results The initial insertion of ureteric access sheath and flexible ureteroscope was successful for 19 sides. And 209 sides of ureter were successfully dilated by double-J stent for 4 weeks. Mini-invasive percutaneous nephrolithotomy (MPCNL) was performed for another 11 sides. Flexible ureteroscope was successfully inserted for 228 sides. In addition to 5 cases with small stone burdens and minimal intraoperative bleeding, others were managed with double J stenting for about 2-4 weeks post-operation. Stone-free status was routinely determined by urinary tract ultrasonography or spiral CT. And 148/228 sides (64. 9%) remained stone-free at 4 weeks after primary operation and overall stone-free rate was 89. 9% (205/228) at 3 months. Ureteroscopic procedures were performed twice or thrice for 75 sides. The average operative duration was 55 (25 - 115) min end average postoperative length of stay 3. 5 (2 -5) days. Severe complications included laceration at ureteral orifice (n = 5) and injury at ureteropelvic junction (n = 3). The latter included perforation at ureteropelvic junction (n =1). All of them were managed with double J stenting. There was one case of renal hematoma. During followups, one child of stricture of ureteropelvic junction was cured by pyeloureteroplasty 6 months later. Up until March 2022, recurrent calculi were detected ( n = 10) . Conclusion Combining flexible ureteroscopy and holmium laser lithotripsy is both safe and effective for upper tract calculi in children. It offers high stone-free rate and fewer complications. [ABSTRACT FROM AUTHOR]

Climate change poses a significant global health challenge, with medical procedures contributing substantially to CO 2 emissions. Urology, as part of the broader healthcare sector, has begun integrating Planetary Health concepts to address this issue. While earlier studies have focused on Life Cycle Assessments (LCA) of urological procedures, these evaluations remain data-dependent, and insights into intra-hospital emissions are limited. This study introduces a methodical approach for analyzing intra-institutional processes of LCA for single-use and reusable flexible ureterorenoscopes (fURS). The LCA method was applied to assess the greenhouse gas emissions (CO 2 equivalents, CO 2 -eq) generated across the life cycle of fURS, including production, use-phase, reprocessing, maintenance, and disposal. The study approximated the Global Warming Potential (GWP) per one-hour use and evaluated associated health impacts using the ReCiPe2016(H) method, which measures Disability-Adjusted Life Years (DALYs). Results showed that for reusable fURS, assuming 133 usages per device and maintenance after every 11th use, each application generated 1.24 kg CO 2 -eq, equivalent to 1.15E-06 DALYs. In contrast, single-use fURS generated 4.93 kg CO 2 -eq and 4.57E-06 DALYs per application. The production and reprocessing stages were identified as having the greatest environmental and health impacts. For reusable fURS, electricity required during refurbishment and use phases was a key contributor, whereas the production phase accounted for most of the impact in single-use devices. Overall, singleuse fURS had a substantially higher potential environmental and health impact than their reusable counterparts. This study underscores the environmental and health impacts of ureterorenoscopy and highlights the importance of incorporating Planetary Health principles into healthcare practices. It provides a foundation for further analyses and research, aiming to drive transformative action in the healthcare sector toward sustainability., Competing Interests: Declarations. Conflicts of interest: MT, JL, JH, IT, AS, MS, SR have no conflict of interest to declare., (© 2024. The Author(s).)

Flexible and navigable suction ureteral access sheath (FANS) is a potential game changer in flexible ureteroscopy (FURS). The influence of sheath size on outcomes needs research. The primary aim was to analyze 30-day single stage stone free status (SFS), zero fragment rate (ZFR) and complications when using 10/12Fr sheaths vis a vis other sheath sizes. The global FANS research group published the 30-day outcomes in patients who underwent FANS and reasoned this can be a potential game changer. We included 295 patients from this anonymized dataset with division into two groups: Group 1 (Smaller sheath) - 10/12Fr FANS, and Group 2 (Larger sheath) - 11/13Fr or 12/14Fr sheaths. Stone volume was similar between both groups (median 1320 mm 3 , p = 0.88). Ureteroscopy and total operative time was longer in the smaller sheath group (35 vs. 32 min, p = 0.02 and 50 vs. 45 min, p = 0.001, respectively). While 30-day computed tomography SFS (100% stone free or single residual fragment ≤ 2 mm) were not significantly different (96% vs. 95%, p > 0.99), ZFR (100% stone-free) was better with smaller sheaths (68% vs. 53%, p = 0.02). There was no difference in postoperative complication rates, and no sepsis in both groups. Urologists should consider individualizing appropriate sheath size in normal adult kidneys. Sheath size did not affect complication rates, risk of perioperative injury to the pelvicalyceal system or ureteric injury, but smaller FANS sheaths had similar high SFS. The ZFR with smaller sheaths was better, but this needs to be validated. These smaller sheath outcomes need to be balanced with longer ureteroscopy time, operative time, reach to the lower pole, ease of suction and visibility during lithotripsy. Large volume studies in different types of pelvicalyceal anatomy can determine if indeed smaller FANS is the best choice in FURS., Competing Interests: Declarations Ethics approval All procedures performed involving human participants were in accordance with the ethical standards of the institutional and/or national research committees and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The study was approved by the Ethics Committee of the Asian Institute of Nephrology and Urology, Hyderabad (#AINU 12/2022). Consent to participate Informed consent was obtained from all individual participants included in the study. Financial disclosures The authors have no relevant financial or non-financial interests to disclose. Competing interests The authors declare no competing interests., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To assess the time taken by the single use 7.5Fr suction flexible ureteroscope to reduce pressure under 40 mm Hg and to characterize the behavior of stones, fragments and dust during suction activation., Methods: An in vitro setting was developed for this experiment. A saline-filled globe, with the 7.5Fr single-use suction flexible ureteroscope, PU3033AH (ZhuHai Pusen Medical Technology Co, Ltd, Guangdon, China), an automatic irrigation pump and a pressure monitoring set were used at four modalities; i) continuous suction, no irrigation inflow; ii) continuous suction, irrigation inflow on; iii) one-second rate intermittent suction, irrigation inflow on, and iv) half-second rate intermittent suction, irrigation inflow on. The behavior of calcium oxalate stones from 0.5 to 5 mm when being aspirated via the ureteroscope into a plastic container filled with saline was recorded., Results: Suction with the PU3033AH worked properly with the inflow irritation on. The fastest strategy to lower the pressure was by continuously pressing the suction button with the irrigation inflow on. Overall, the median time to reach 40 mg was roughly 3.5 s. The PU3033AH could aspirate 0.5 mm stones. The suction mode on a continuous pattern allowed the relocation of stones ranging from 1 to 5 mm on an experimental setup with no obstacles., Conclusion: The PU3033AH was efficient in lowering pressure in a closed cavity mimicking the renal pelvis. Likewise, stone fragments under one millimeter were aspirated by the device whereas stones from one to five mm could be displaced when activating suction in continuous mode on an experimental setup with no obstacles., Competing Interests: Declarations Conflict of interest Dr. Laurian Dragos is lecturer for EMS and Boston Scientific and consultant for Ambu. Dr. Bhaskar Somani is consultant for Pusen, Boston Scientific, Cook Medical, Coloplast and Olympus. Dr. Oriol Angerri is lecturer for Boston Scientific and Cook Medical. Dr. Evangelos Liatsikos is consultant for Cook Medical and Karl Storz and lecturer for Karl Storz, Boston Scientific, EMS and Redpine. Dr. Panagiotis Kallidonis is lecturer for EMS and Cook Medical. None of the rest of authors have any conflict of interest to disclose., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: To compare intrarenal pressure (IRP) and irrigation flow by varying suspended water heights and hand-held pressure pumping during flexible ureteroscopy using an in vitro 3D printed kidney model., Methods: A 3D-printed silicone model was used to simulate the kidney. The ureteral access sheath(UAS) was connected to the kidney model and positioned at the ureteropelvic junction. Central venous pressure tubing was used to monitor the pressure in the renal pelvis under different conditions. Sheath sizes of 12Fr and 14Fr were tested with flexible ureteroscope (fURS) sizes of 7.5, 8.5, and 9.5Fr, respectively. The irrigation was gravity-based, with suspended water heights set at 60, 90, 120, 150, and 180 cm. The manual pumping as another set of measurement is used to measure the maximum intrarenal pressure., Results: Using a 12Fr sheath with a 9.5Fr fURS loading without additional accessories resulted in IRP ranging from 8.4 to 17.5 cmH2O, while manual pumping perfusion pressure exceeded 60 cmH2O. Loading a 200-um laser fiber reduced the pressure to 6.4-10.5 cmH2O, and using a stone basket decreased it to 4.0-5.0 cmH2O. Using a 14Fr sheath with a 9.5Fr fURS resulted in an IRP of 2.5-6.0 cmH2O, compared to 17 cmH2O with manual pumping. With a 12Fr sheath and a 7.5Fr fURS, the IRP ranged from 5.4 to 8.2 cmH2O, while manual pumping resulted in 25.5 cmH2O. With a 14Fr sheath and a 7.5Fr fURS, the IRP ranged from 1.5 to 4.3 cmH2O, and manual pumping resulted in 9.0 cmH2O., Conclusion: When using a UAS in a flexible ureteroscopy, the IRP can be maintained within a safe range with different fURS/UAS combos with a suspended water height of less than 180 cm. However, with specific fURS/UAS(9.5Fr/12Fr) combos, the IRP exceeded the safe limit when using manual pumping. Gravity irrigation with a suspended water height of less than 180 cm is safe in this simulated clinical environment., (© 2024. The Author(s).)

Purpose: This study aims to evaluate the efficacy of tip-flexible suctioning ureteral access sheath (TFS-UAS) compared to traditional ureteral access sheath (T-UAS) in flexible ureteroscopic lithotripsy (FURL) for unilateral upper urinary tract calculi., Methods: The study retrospectively compared outcomes from 103 cases using TFS-UAS and 138 using T-UAS treated with FURL for unilateral upper urinary tract calculi from January to October 2023. Assessed parameters included patient demographics, stone characteristics, preoperative urine cultures, ureteral pre-stenting, comorbidities, procedure time, stone-free rate (SFR), utilization of stone retrieval baskets, and postoperative Systemic Inflammatory Response Syndrome (SIRS) rates. The maximum angle of deflection was also measured when the flexible ureteroscope was located in different parts of the TFS-UAS with different diameters in vitro., Results: The TFS-UAS group achieved a higher Immediate SFR (76.70% vs. 63.77%, p = 0.031) and final SFR (89.32% vs. 73.91%, p = 0.003) than the T-UAS group, especially in the lower calyx stones (80.00% vs. 41.18%, p = 0.018) and upper urinary tract calculi with a cumulative diameter of 2 cm or larger (68.97% vs. 42.11%, p = 0.029). Notably, TFS-UAS with a 10 French (F) inside diameter size achieved a higher SFR (88.57% vs. 70.59%, p = 0.041) and a greater deflection angle than the 12.5 F inside diameter size. No significant variations were observed in the operative duration, hospitalization duration and the occurrence of SIRS between the compared cohorts., Conclusion: TFS-UAS significantly improves SFR in FURL treatment of unilateral upper urinary tract calculi, particularly for stones located in the lower calyx or with a cumulative diameter of 2 cm or greater, compared to T-UAS., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To create a machine-learning model for estimating the likelihood of post-retrograde intrarenal surgery (RIRS) sepsis., Methods: All consecutive patients with kidney stone(s) only undergoing RIRS in 16 centers were prospectively included (January 2022-August 2023)., Inclusion Criteria: adult, renal stone(s) only, CT scan (within three months), mid-stream urine culture (within 10 days)., Exclusion Criteria: concomitant ureteral stone, bilateral procedures. In case of symptomatic infection/asymptomatic bacteriuria, patients were given six days of antibiotics according to susceptibility profiles. All patients had antibiotics prophylaxis. Variables selected for the model: age, gender, age-adjusted Charlson Comorbidity Index, stone volume, indwelling preoperative bladder catheter, urine culture, single/multiple stones, indwelling preoperative stent/nephrostomy, ureteric access sheath, surgical time. Analysis was conducted using Python programming language, with Pandas library and machine learning models implemented using the Scikit-learn library. Machine learning algorithms tested: Decision Tree, Random Forest, Gradient Boosting. Overall performance was accurately estimated by K-Fold cross-validation with three folds., Results: 1552 patients were included. There were 20 (1.3%) sepsis cases, 16 (1.0%) septic shock cases, and three more cases (0.2%) of sepsis-related deaths. Random Forest model showed the best performance (precision = 1.00; recall = 0.86; F1 score = 0.92; accuracy = 0.92). A web-based interface of the predictive model was built and is available at https://emabal.pythonanywhere.com/ CONCLUSIONS: Our model can predict post-RIRS sepsis with high accuracy and might facilitate patient selection for day-surgery procedures and identify patients at higher risk of sepsis who deserve extreme attention for prompt identification and treatment., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Flexible and navigable suction ureteral access sheaths (FANS) have been introduced without current evidence on how to optimize deflection. Aim was to evaluate in vitro deflection angles with 2 different FANS techniques-sheath advancement and ureteroscope deflection; and effects of sheath size-ureteroscope combinations., Methods: We evaluated in vitro deflection angles of 10/12Fr, 11/13Fr and 12/14Fr FANS (Hunan Reborn Medical Co. Ltd) with six single-use flexible ureteroscopes (Pusen Uscope 7.5Fr, OTU WiScope 7.5Fr, OTU WiScope 8.6Fr, Innovex EU-scope 8.7Fr, Red Pine RP-U-C12 8.7Fr and Boston Scientific Lithovue 9.5Fr). Two deflection techniques were tested: (1) sheath advancement-advancing the sheath forward over a maximally deflected ureteroscope, and (2) ureteroscope deflection-maximally deflecting the ureteroscope from various starting positions relative to tip of the sheath., Results: Intra and inter-scope comparisons of maximum deflection angles were significantly different (all ANOVA p < 0.01). Largest maximum angles for all ureteroscopes were with the sheath advancement technique (range 218°-277°), and second largest for most scopes using the ureteroscope deflection technique at tip (range 111°-212°), mostly deviating from manufacturer specifications (range 270°-275°). 10/12Fr and 11/13Fr sheath sizes were more flexible than 12/14Fr. Largest angles were with 11/13Fr sheath-OTU8.6Fr/Innovex8.7Fr combinations., Conclusion: Optimal deflection with FANS is achieved using either a sheath advancement technique, or ureteroscope deflection technique at tip. Despite using these optimized techniques, deflection angles specified by manufacturers seem hardly achievable. The sheath advancement technique and 11/13Fr sheath-OTU8.6Fr/Innovex8.7Fr combinations may be better suited for lower pole situations. Urologists should be aware of these differences and apply the findings to their FANS technique., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: To explore the feasibility and safety of aflexible ureteroscopy with intelligent control of renal pelvic pressure(FUS-ICP) without a post-operative indwelling urinary catheter ., Methods: In this retrospective study, we assessed patients with upper urinary tract stones who were treated with FUS-ICP at the Ganzhou People's Hospital from February 2022 to December 2023. Patients were divided into the non-urinary catheter (non-UC) and urinary catheter (UC) groups according to whether an indwelling catheter was used after surgery., Results: In total, 142 patients were included in the study. There was no significant difference in the preoperative general data between the two groups. Patients in the non-UC group performed better than those in the UC group in terms of catheter-related bladder irritation (P = 0.001), the Sedation-Agitation Scale score (P = 0.012), and the numerical rating scale (P = 0.003). The incidences of urinary retention (P = 0.620), urinary tract infection (P = 0.529), and replacement of urethral catheter s (P = 0.438) in the UC group were inferior to those in the non-UC group, but there was no statistical significance., Conclusions: It is feasible and safe to perform FUS-ICP without a post-procedure indwelling urinary catheter., (© 2024. The Author(s).)

Purpose: To evaluate and compare the clinical results of different single-use flexible ureteroscopes (su-fURS) used in retrograde intrarenal surgery (RIRS)., Materials and Methods: RIRS cases performed identically by an experienced surgeon between 2022 and 2023 in a single center were retrospectively analyzed. These surgeries were performed with three su-fURS (Redpine RP-U-C12, Hugemed HU30, and Pusen Uscope 3022 A). In the study, the age, gender, body mass index, and Charlson comorbidity index of the patients were compared, along with their clinical details, such as the stone size, volume, density, location, and history of hydronephrosis or a double J stent or SWL. Operation time, stone-free rates (SFR), perioperative and postoperative complications, and hospitalization times were also compared., Results: The study included 208 patients. Pusen had 63 cases, Hugemed had 62, and Redpine had 83. The comparison of the patient's demographic and clinical properties with stone-related variables was similar between the groups. The SFR was similar between the groups (p = 0.056). Perioperative, postoperative, and total complication rates and the need for a second intervention showed no significant differences among the three groups (p = 0.324, 0.088, 0.061, and 0.052, respectively)., Conclusion: In the first study comparing the clinical results of cases in which different su-fURS were used, no difference was observed in surgical outcomes and complications, even though the technical features of these devices were different. Urologists should select su-fURS based on clinical requirements, financial constraints, and personal experiences., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The correlation between novel negative pressure ureteroscopic lithotripsy (NP-URL) combined with flexible ureteroscopy (FU) and percutaneous nephrolithotomy (PCNL) on stone-free rates (SFR) remains unclear. There is a lack of evidence from Chinese populations regarding the relationship between SFR and NP-URL combined with FU (NP-URL-FU) versus PCNL. We aimed to assess the association between NP-URL-FU and PCNL on SFR. We conducted a cohort study involving 166 participants with 2-4 cm kidney stones. Data on SFR (7 days and 2 months) were collected from all participants. Logistic regression analysis was used to substantiate the research objectives. NP-URL-FU versus PCNL showed an 86% decrease in the 7-day SFR (OR = 0.14, 95% CI 0.07-0.29). The results remained stable even after adjusting for potential confounders. However, no statistically significant association was found between the surgical method and the 2-month SFR. Further exploratory subgroup analyses showed no significant interactions, with all P values > 0.05. Among patients with 2-4 cm kidney stones, NP-URL-FU was associated with a lower risk of incident 7-day SFR than PCNL. However, no statistically significant difference was found in the long-term stone removal rate. Therefore, NP-URL-FU may be a viable alternative surgical option for patients seeking minimally invasive procedures., (© 2024. The Author(s).)

Objective: This study aimed to evaluate the accuracy and effectiveness of renal pelvic pressure (RPP) control during flexible ureteroscopic perfusion at various sites., Methods: Flexible ureteroscopy for the intelligent control of RPP was based on a ureteral access sheath (UAS) that integrated pressure measurement and suction functions (with automatic adjustment). Eleven consecutive patients with indurating nephrostomy tubes were enrolled. The nephrostomy tube was connected to a disposable invasive blood pressure sensor. The RPP was zeroed after the pressure stabilized. The flow rate and control value were set at 100 ml/min and - 5 mmHg, respectively. An 8.5 Fr flexible ureteroscope was irrigated at the renal pelvis, as well as the upper, middle, and lower calyces of the kidney for 1 min., Results: All 11 patients with upper urinary tract calculi underwent successful UAS placement. Pressures measured by the sheath and fistula during perfusion were - 5.07 ± 1.41 and - 4.89 ± 1.07 mmHg at the renal pelvis, -5.16 ± 1.36 and - 5.12 ± 1.32 mmHg at the upper calyces, -4.98 ± 0.87 and - 5.39 ± 1.01 mmHg at the middle calyces, as well as -4.95 ± 1.56 and - 5.64 ± 1.24 mmHg at the lower calyces, respectively. There were no significant differences in pressure between the sheath and fistula groups or in sheath and fistula pressures among parts. The RPP fluctuated; however, all values were within the safe limit of 20 mmHg., Conclusion: The UAS-based pressure monitoring technology can accurately and reliably monitor and control RPP within a set range., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: A new digital single-use flexible ureteroscope, Pusen direct in scope suction (DISS) 7.5Fr (PU3033AH), was evaluated with respect to manoeuvrability, suction quality, visibility and clinical efficiency., Methods: A prospective cohort study was conducted in six tertiary reference centers in Europe and Asia between February-April 2024. Adult patients who underwent flexible ureteroscopy and laser lithotripsy (fURSL) for urolithiasis were included. Demographic, intraoperative and follow-up characteristics were recorded. Quality parameters were rated by each surgeon using a Likert scale., Results: a total of 57 fURSL were performed. Preoperative characteristics revealed a mean stone volume of 480.00mm 3 (mean Hounsfield Unit- 998). 57.9%(n = 33) of the patients were pre-stented, and a ureteric access sheath was used in 64.9%(n = 37). Integrated-suction was deemed helpful in 94.7%(n = 54) fURSL as reported by the operators. An initial stone free rate (SFR) confirmed by postoperative imaging was achieved in 84.21%(n = 48). Quality parameters of the scope reached a mean Likert score of 4.5, with a "very good" mean evaluation for "scope placement", "visual quality", "irrigation", "deflection", "manoeuvrability", and "weight". "Suction quality" and "overall performance satisfaction" were rated "good". Comparing the Pusen DISS scope with other previously used scopes, overall satisfaction was rated 4.1. When asked if the surgeons would be willing to use the Pusen DISS 7.5Fr scope in the future, all the six surgeons answered positively., Conclusion: The DISS 7.5 Pusen ureteroscope displayed good visibility, manoeuvrability and suction quality, with excellent operative results. Further evaluation with larger comparative cohorts will help understand the potential of in-vivo use of integrated suctioning systems for fURSL., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: While the efficacy of flexible ureterorenoscopy (URS) in managing solitary kidney stones (KSs) is widely acknowledged, its effectiveness in treating multiple stones has scarcely been investigated. This study aims to assess the effectiveness and safety of retrograde intrarenal surgery (RIRS) utilizing flexible URS and laser lithotripsy in the management of multiple KSs.  Methods: This study was a single-group cohort study conducted on patients with multiple KSs who underwent treatment with RIRS using flexible URS and laser lithotripsy. Stone-free status was considered as the lack of residual stone fragments or any residual stone of any size. The first follow-up appointment was arranged 3-4 weeks following the procedure. If significant residual stones were present, patients underwent reintervention within 2-4 weeks., Results: A total of 110 patients with multiple KSs were included. The mean stone burden was 27.5 ± 7.9 mm, and the mean duration of the operation was 54.9 ± 19.7 minutes. Seven cases (6.3%) experienced intraoperative complications, while postoperative complications were found in eight cases (7.3%). After four weeks, a stone-free rate (SFR) was documented in 80.9% of the cases, and this rate increased to 93.6% after three months. The SFR after three months was significant with Guy's stone score (p < 0.001); however, it did not reach a significant level with any other parameters.  Conclusions: The RIRS with flexible URS may be an effective and potentially safe procedure for treating multiple KSs. It may yield a favorable SFR with an acceptable complication rate.

Purpose: This study aims to evaluate the clinical efficacy of using a tip‑flexible suctioning ureteral access sheath (TFS-UAS) in combination with a traditional ureteral access sheath (T-UAS) and a disposable flexible ureteroscope (DFU) for treating large renal stones (2-4 cm in diameter)., Methods: We retrospectively collected clinical data from 238 patients who underwent retrograde intrarenal surgery (RIRS) at Ganzhou People's Hospital between January 2019 and October 2023. The study included 238 patients who met the inclusion criteria, with 125 in the observation group using TFS-UAS and 113 in the control group using T-UAS. We compared differences in the stone-free rate (SFR), complication rates, surgery duration, and average hospital stay between the two groups., Results: All 238 surgeries were successfully completed. The stone-free rates for the observation group at the first and thirtieth day post-surgery were 87.20% and 95.20%, respectively, whereas for the control group, the rates were 73.45% and 85.84%, showing statistically significant differences (P < 0.05). The overall complication rates were 1.6% for the observation group and 14.16% for the control group, also statistically significant (P < 0.001). The surgical times for stone removal were (101.17 ± 25.64) minutes for the observation group and (86.23 ± 20.35) minutes for the control group, with significant differences (P < 0.05)., Conclusion: Compared to T-UAS, combining TFS-UAS with DFU for treating renal stones of 2-4 cm diameter, although more time-consuming, resulted in higher SFRs and improved safety., (© 2024. The Author(s).)

To compare the outcomes of using Ultrathin semirigid retrograde ureteroscopy and antegrade flexible ureteroscopy to treat proximal ureteric stones of sizes 1-2 cm. A prospective randomized multicenter study included patients who had proximal ureteric stones 1-2 cm, amenable for ureteroscopy and laser lithotripsy between August 2023 and February 2024. Two hundred thirty patients were divided evenly into two treatment groups. Group I included patients treated with antegrade flexible ureteroscopy and holmium laser stone fragmentation, and Group II included patients treated with retrograde ultrathin semirigid ureteroscopy. The study groups were compared in terms of patient demographics, stone access success, operation time, reoperation rates, peri-operative complications, and stone-free status. Group I included 114 patients, while Group II included 111. The mean age of the patients was 33.92 ± 10.37 years, and the size of the stones was 15.88 ± 3 mm. The study groups had comparable demographics and stone characteristics. The mean operative time was significantly longer in group I than in group II (102.55 ± 72.46 min vs. 60.98 ± 14.84 min, respectively, P < 0.001). Most reported complications were MCCS grades I and II, with no significant difference between the study groups. The stone-free rate after four weeks was 92.1% and 81.1% for groups I and II, respectively, which increased to 94.7% and 85.6% after eight weeks (P > 0.05). Antegrade flexible ureteroscopy is equivalent to retrograde ultrathin semirigid ureteroscopy in treating proximal ureteric stones regarding stone-free status and procedure-related morbidity. However, the antegrade approach has a longer operative time, greater fluoroscopy exposure, and longer hospital stays., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: This study aims to assess stone-free rates after flexible ureterorenoscopy (fURS) using the T.O.HO. (Tallness, Occupied lesion, Hounsfield unit evaluation) scoring system and Ito's nomogram., Materials and Methods: In the study conducted with 484 patients, the following parameters were analyzed: age, sex, comorbidities, hospitalization, affected side, extracorporeal shock wave lithotripsy (ESWL) history, stone length, stone density, number of stones, location, and presence of hydronephrosis., Results: Multivariate logistic regression analysis revealed that stone length, stone number, and lower pole stone location were associated with the prediction of stone-free status. The cut-off value for Ito's score was determined to be 13.5 points, with an AUC of 0.792 (sensitivity, 0.609; specificity, 0.821) and a 95% confidence interval of (0.752-0.832) (Fig. 1). The cutoff for the T.O.HO. score was 6.5 points, with an AUC of 0.744 (sensitivity 0.738, specificity 0.602) and a 95% confidence interval of (0.699-0.789)., Conclusion: In conclusion, T.O.HO. scoring system and the Ito's nomogram are promising tools to predict stone-free status (SFS) after fURS in preoperative evaluation. In addition, the success of scoring systems in predicting SFS preoperatively appears promising and offers a potentially valuable approach., (© 2024. The Author(s).)

Background: To compare the operative effect and clinical efficacy of the Moses laser mode and the Raykeen holmium laser energy platform powder mode under flexible ureteroscopic lithotripsy in patients with impacted upper ureteral stones., Methods: From March 2022 to September 2022, 72 patients were divided into a Moses laser group and a Raykeen laser group according to surgical method, with 36 patients in each group. CT and ureteroscopy confirmed that all patients had isolated impacted upper ureteral stones. The stone volume (mm 3 ), stone density (Hu) and severity of hydronephrosis were measured by CT. Postoperative complications were evaluated using the Clavien-Dindo score., Results: There were no complications of ureteral stenosis related to the laser treatment. The operative time and lithotripsy time were lower in the Moses laser group than in the Raykeen laser group (P < 0.05). The stone-free survival rate did not differ significantly between the two groups (P = 0.722). Stone volume was found to be positively correlated with laser energy and lithotripsy time in both groups (P < 0.01). There was no significant correlation between laser energy and lithotripsy time or ureteral stone density (Hu) in the Moses laser group (P > 0.05) or the Raykeen laser group (P > 0.05)., Conclusions: The contact mode of Moses technology and the powder mode of Raykeen laser lithotripsy can be used for the ablation of a single impacted upper ureteral stone. The ablation speed was related to the stone volume and the severity of polyp hyperplasia, not the stone density. We recommend the use of the powdered mode as a therapeutic measure for the treatment of impacted upper ureteral stones in flexible ureteroscopic lithotripsy., (© 2024. The Author(s).)

Purpose: To evaluate the stone clearance rate and limitations of a novel integrated suction capability within a single-use flexible ureteroscope according to stone particle size., Methods: Varying sized stone particles were created using a stone phantom (Begostone Plus, Bego ©, Lincoln, RI, USA). Particle size ranged as follows: 63-125 µm, 125-250 µm, 250-500 µm, 500 µm- 1 mm and 1-2 mm. These were mixed with Normal saline (0.9%) to mimic in vivo conditions. The suction enabled single-use flexible ureteroscope (Pusen, Zhuhai, China) was used to aspirate stone fragments in three trials. Firstly, aspiration of 5 g of each dust range was attempted. Secondly, a direct comparison of the integrated suction to a manual syringe technique was applied to 1 g of each size range. Finally, aspiration was applied to 5 g of a heterogenous 1:1:1:1:1 mixture. Endoscopic clearance rate (g/min) and number of blockages were recorded. Each challenge was repeated three times., Results: The integrated suction cleared 100% of dust < 250 µm. Endoscopic clearance rates were significantly faster than manual aspiration (3.01 g/min versus 0.41 g/min) for dust between 125 and 250 µm (p = 0.008). Complete endoscopic clearance by 180 s (without encountering test limiting blockages) was unsuccessful for particles > 250 µm. Clearance rates were greatly limited by stone particle size heterogeneity above 250 µm, to 0.09 g/min., Conclusion: This technology works better in vitro than previously DISS evaluated methods when challenged by stone dust < 250 µm. However, this adaptation is significantly challenged in the presence of stone dust particles > 250 µm., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: To evaluate the efficacy of a novel temperature control flexible ureteroscope system in the precise monitoring and control of intrarenal temperature (IRT) during ureteroscopy., Methods: We developed a novel temperature control flexible ureteroscope system (PT-Scope), including a temperature-monitoring ureteroscope and a irrigation-suction platform for temperature regulation. A porcine thermometry model was established to observe temperature changes under varying holmium laser powers (10, 20, 30 W) and irrigation rates (0, 20, 50 mL/min), utilizing percutaneous nephrostomy thermometry and PT-Scope measurements, with subsequent evaluation of temperature variations at different distances from the laser fiber tip. A porcine kidney stone model was established while porcine was randomly assigned to two groups: In the temperature control group, PT-Scope was connected to the irrigation-suction platform with temperature regulation, while in the nontemperature control group without temperature regulation. Comparative analysis was performed to evaluate differences in IRT between the two groups., Results: Across various laser powers and irrigation rates, the temperature measurement capability of the PT-Scope was precise, demonstrating consistency with percutaneous nephrostomy temperature measurements. The temperature obtained from the PT-Scope reflect the temperature approximately 0.05 cm away from the fiber tip, whereas temperatures close to fiber tip were significantly higher. The peak temperature of the temperature control group vs nontemperature control group were 31.70 ± 2.609°C and 44.37 ± 3.318 °C, respectively (P < 0.01). The mean temperature of the temperature control group vs nontemperature control group was 27.40 ± 2.107 °C vs 35.9 ± 1.921 °C (P < 0.01)., Conclusion: PT-Scope has demonstrated the capability to precisely monitor and control IRT within a safe threshold., Competing Interests: Declaration of Competing Interest The authors have no conflict of interest to declare., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: We sought to evaluate the technical feasibility of performing a combined robotically assisted mini-percutaneous nephrolithotomy (PCNL) and flexible ureteroscopy (URS) procedure by a single urologist using the MONARCH Platform, Urology (Johnson & Johnson MedTech, Redwood City, California)., Material and Methods: In this prospective, first-in-human clinical trial, 13 patients underwent robotically-assisted PCNL for renal calculi at the University of California-Irvine, Department of Urology. Successful completion of the procedure was assessed as the primary endpoint. Postoperative adverse events were monitored for 30 days following the completion of the procedure. Stone ablation efficiency was evaluated on postoperative day 30 with low-dose 2-3 mm slice CT scans. Patients were classified according to the maximum length of their residual stone fragments as either absolute stone-free (Grade A), < 2 mm remnants (Grade B), or 2.1-4.0 mm remnants (Grade C)., Results: The combined robotic mini-PCNL and URS procedure was successfully completed in 12 of 13 procedures. No robotic device-related adverse events occurred. Preoperative stone burden was quantified by both maximum linear measurement (median 32.8 mm) as well as by CT-based volume (median 1645.9 mm 3 ). Using the unique robotically assisted targeting system, percutaneous access was gained directly through the center of the renal papilla in a single pass in all cases. Median operative time was 187 minutes (range: 83-383 minutes). On postoperative day 30, a 98.7% (range: 72.9%-100.0%) volume reduction was achieved, with 5 Grade A (38.5%), 1 Grade B (7.7%), and 2 Grade C (15.4%). Three patients experienced complications (2 grade 1 and one grade 2 Clavien-Dindo)., Conclusions: Our preliminary investigation demonstrates the safety, efficacy, and feasibility of a unique robotic-assisted combined mini-PCNL and URS platform.

Introduction: We sought to compare the safety, efficacy, efficiency, and surgeon experience during upper urinary tract stone management with single-lumen (SLFU) vs dual-lumen flexible ureteroscopes (DLFU). Materials and Methods: Seventy-nine patients with proximal ureteral or renal stone burden <2 cm were randomized to a SLFU or DLFU. We recorded times for ureteroscopy (URS), laser lithotripsy, stone basketing, as well as intraoperative and postoperative complications. The rate of stone clearance and stone free status were calculated using CT imaging. Surgeons completed a survey after each procedure rating various metrics regarding ureteroscope performance. Results: Thirty-five patients from the single-lumen group and 44 patients from the dual-lumen group had comparable median URS time (37 vs 35 minutes, p = 0.984) and basketing time (12 vs 19 minutes; p = 0.584). Median lithotripsy time was decreased in the dual-lumen group (single: 6 vs dual: 2 minutes, p = 0.017). The stone clearance rate was superior in the dual-lumen group (single: 3.7 vs dual: 7.1 mm3/min, p = 0.025). The absolute stone-free rate (SFR) was superior for the dual-lumen group (single: 26% vs dual: 48%, p = 0.045). No differences in intraoperative (single: 0% vs dual: 2%; p = 0.375) and postoperative complications (single: 7% vs dual: 11%, p = 0.474) were observed. Surgeons' ratings of the dual-lumen ureteroscope was superior for visibility, comfort, ease of use, and overall performance. Conclusions: The use of the dual-lumen ureteroscope in patients with renal and proximal ureteral stones <2 cm provided shorter lithotripsy time, higher stone clearance rates, improved SFR, and superior surgeon ratings when compared with SLFUs. [ABSTRACT FROM AUTHOR]

PurposeCareful decontamination and sterilization of reusable flexible ureteroscopes used in ureterorenoscopy cases prevent the spread of infectious pathogens to patients and technicians. However, inefficient reprocessing and unavailability of ureteroscopes sent out for repair can contribute to expensive operating room (OR) delays. Time-driven activity-based costing (TDABC) was applied to describe the time and costs involved in reprocessing.Materials and methodsDirect observation and timing were performed for all steps in reprocessing of reusable flexible ureteroscopes following operative procedures. Estimated times needed for each step by which damaged ureteroscopes identified during reprocessing are sent for repair were characterized through interviews with purchasing analyst staff. Process maps were created for reprocessing and repair detailing individual step times and their variances. Cost data for labor and disposables used were applied to calculate per minute and average step costs.ResultsTen ureteroscopes were followed through reprocessing. Process mapping for ureteroscope reprocessing averaged 229.0 ± 74.4 minutes, whereas sending a ureteroscope for repair required an estimated 143 minutes per repair. Most steps demonstrated low variance between timed observations. Ureteroscope drying was the longest and highest variance step at 126.5 ± 55.7 minutes and was highly dependent on manual air flushing through the ureteroscope working channel and ureteroscope positioning in the drying cabinet. Total costs for reprocessing totaled $96.13 per episode, including the cost of labor and disposable items.ConclusionsUtilizing TDABC delineates the full spectrum of costs associated with ureteroscope reprocessing and identifies areas for process improvement to drive value-based care. At our institution, ureteroscope drying was one clearly identified target area. Implementing training in ureteroscope drying technique could save up to 2 hours per reprocessing event, potentially preventing expensive OR delays.

ObjectiveLithoVue™ is a novel, single-use, digital flexible ureteroscope that was released to the US market in January 2016. There are scant data regarding its performance in humans. Procedural outcomes comparing LithoVue with reusable ureteroscopes are presented in patients undergoing ureteroscopy for upper urinary tract pathology.Patients and methodsClinical outcomes between two groups of patients undergoing flexible ureteroscopy for upper urinary tract pathology were analyzed. The first group underwent surgery utilizing LithoVue, and the second group used reusable fiber-optic flexible ureteroscopes. Differences in procedural outcomes, operative times, and time spent in hospital were analyzed using two-tailed t-tests and chi-squared and Fisher's exact tests.ResultsOne hundred fifteen cases utilizing LithoVue and 65 cases utilizing reusable ureteroscopes were included in this study. Demographics, surgical indications, stone size, location, total stone burden, composition, procedural outcomes, and complications were comparable between groups. For all cases, LithoVue procedures lasted 54.1 ± 25.7 minutes compared with 64.5 ± 37.0 minutes for reusable scope procedures (p

Background: In robot-assisted flexible ureteroscopy, planning a safety-enhanced path facilitates ureteroscope reaching the target safely and quickly. However, current methods rarely consider the safety impact caused by body motion of the anterior part, such as impingement on the lumen wall and sweeping motion risk, or the method can only be used in collision-free situations., Methods: The kinematic model of the anterior part under C-shaped and S-shaped collision bending is first analysed. Considering the newly defined impingement cost and sweeping area, the differential evolution algorithm is adopted to optimise the path in the configuration space. Experiments were performed to verify the effectiveness of the method., Results: Compared with the competing algorithm, the proposed algorithm reduced impingement cost and sweeping area by an average of 31.0% and 8.64%. Force measurement experiments verified the rationality of the impingement cost expression., Conclusion: The experimental results proved the feasibility of the proposed path planning algorithm., (© 2024 John Wiley & Sons Ltd.)

Objectives: To investigate the safety of short-term stenting following flexible ureteroscopic lithotripsy (fURL) for patients without preoperative stents. Retaining double-J stent for 1-2 weeks after fURL is a common practice. At present, data on short-term stenting after non-pre-stented fURL is still lacking., Methods: 182 patients who met inclusion criteria were retrospectively divided into the 2-days group (2-day removal, 76 cases) and the 1-week group (1-week removal, 106 cases). The study endpoint was stent-associated adverse symptoms assessed by follow-up and completed validated questionnaires on postoperative days (POD) 7 and 12. A postoperative imaging review was performed 1 month after the surgery., Results: No statistical differences were found in the patients' demographic and stone-related characteristics. The 2-days group showed fewer urinary tract symptoms and lower scores on the ureteral stent symptom questionnaire on POD 7: less backache during urination (p = 0.004), less hematuria (p = 0.031), less frequent urination (p = 0.004), lower urinary symptoms index (p < 0.001), lower general health index (p < 0.001), and lower performance index (p < 0.001). There were no significant differences in fever (p = 0.372), visual analogue scale score (p = 0.760), and painkiller requirements (p = 0.160) on POD 7. The average general health score and work performance score remained significantly higher in the 1-week group patients at 5 days after removal compared to the 2-days group patients at 5 days after removal. (p < 0.001, p = 0.005). Five patients in the 2-days group and 15 patients in the 1-week group returned to the emergency department for additional treatments. No patient required rehospitalization. Stone-free rates were 85.5% in the 2-days group and 80.2% in the 1-week group (p = 0.499), respectively, and none of the patients got aggravating hydronephrosis., Conclusions: Compared to the common 1-week stent removal option, short-term stenting after non-pre-stented fURL is safe, which can enhance the patient's quality of life., (© 2024. The Author(s).)

Objectives: To report our initial experience of one-stage flexible ureteroscopic lithotripsy(FURL) with 11/13Fr suctioning ureteral access sheath(UAS) and 8.55Fr single-use digital flexible ureteroscope(SDFU) in upper ureteral or renal calculi., Materials and Methods: We retrospectively collected the clinical data of 900 adult patients with upper ureteral or renal calculi treated by FURL with 11/13Fr suctioning UAS and 8.55Fr SDFU from January 2022 to April 2024. Demographics, peri- and postoperative outcomes were assessed., Results: In all, 40 of 940 cases(4.26%) failed to introduce UAS and required second-stage FURL because of ureterostenosis and were excluded. Mean stones size of the remaining 900 eligible cases was 1.68 ± 0.58 cm in greatest diameter. There were 228 cases of upper ureteral stone, 456 cases of renal stone and 216 cases of concomitant ureteral and renal calculi. The mean operation time was 52.20 ± 20.21 min and the postoperative hospital stay was 2.87 ± 1.37 days. The stone-free rate of 1 month postoperatively was 89.56% and only 2.44% of patients with residue underwent additional reoperation. The rate of postoperative fever, postoperative pain needing analgesic and slight ureteral mucosal injury were 5.11%, 8.22% and 7.78%, respectively. None of patient suffered from severe complications, such as sepsis or ureteral perforation., Conclusion: It's practical and suitable for the vast majority of adult patients to undergo FURL in single session with 11/13Fr suctioning UAS without preoperative stenting. FURL with 11/13Fr suctioning UAS and 8.55Fr SDFU is feasible, reliable, safe, and efficient in the management of renal stone and upper ureteral stone., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: To systematically synthesize existing reported literature calculating the carbon footprint (CFP) of urological surgical practice and identify opportunities for improving the environmental impact of urology surgical practice., Methods: A systematic review was performed following PRISMA guidelines. The Cochrane, Embase, Ovid MEDLINE, and PubMed were searched between 1971 and 2023, with inclusion and exclusion criteria. The outcome measures were mapped across the included studies including assessment of risk of bias., Results: A total of 345 studies with titles were identified from an initial search, however only 5 were included. Three studies compared singleuse with reusable cystoscopes concluded that single-use cystoscopes are non-inferior to reusable cystoscopes environmentally due to the carbon footprint associated with decontamination and repackaging. Similarly, in a single study, the CFP of single-use and reusable ureteroscopes is comparable. Lastly, a single study concluded that robotics-assisted surgery in prostate cancer may be a better option than other approaches in terms of environmental sustainability., Conclusions: In conclusion, although minimally invasive (including robotic approaches) and endoscopic surgeries offer significant opportunities to improve healthcare we do need to consider the environmental impact. However, there is a paucity of good-quality literature to guide urological surgical practice to reduce the CFP and improve sustainability., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The purpose of this study is to compare the outcomes of transperitoneal laparoscopic ureterolithotomy (TPLU), retrograde flexible ureteroscopy (R-fURS), and mini-percutaneous antegrade flexible ureteroscopy (A-fURS) for treating large (≥ 15 mm) impacted proximal ureteral stones. A total of 105 adult patients were randomized into 3 equal groups: group A (35) patients underwent TPLU, group B (35) patients underwent R-fURS, and group C (35) patients underwent A-fURS. The initial stone-free rate was 100%, 68.6%, and 80% in groups A, B, and C, respectively. The mean operative time (OT) was (85.0 ± 7.57 min) in group A, (61.0 ± 8.21 min) in group B, and (89.57 ± 15.12 min) in group C. The three groups were comparable concerning the overall complications. R-fURS is a less invasive modality for treating such stones; however, it is associated with a lower SFR and a higher rate of auxiliary procedures. Both TPLU and miniperc A-fURS are effective and valuable alternatives for treating large impacted proximal ureteric stones., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: To report real-time IRP and FR while performing flexible ureteroscopy in porcine kidney model utilizing LithoVue™ Elite (Boston Scientific®) with different irrigation systems, including automated pumps., Methods: Using an ex-vivo model of porcine kidney, IRPs were measured with LithoVue Elite. Ureteroscopic settings (US) were tested with all permutations of irrigation methods (IM), working channel occupant (WCO), and ureteral access sheaths (UAS). IMs included: Single Action Pumping System (SAPS™, Boston Scientific), Thermedx FluidSmart™ (Stryker®), and ENDOMAT™ (Karl Storz®). Pumps were tested at 50, 100, and 150 mmHg. WCOs included a 1.9Fr zero-tip basket, 200 µm, and 365 µm laser fibers. UASs utilized 11/13Fr and 12/14Fr 36 cm., Results: 84 different US were tested (252 experiments). ENDOMAT had higher IRP but the same FR as Thermedx at the same US for 50 and 100 mmHg (p < 0.01). SAPS had higher IRP and FR than pumps in all US studies (p < 0.01). There was positive correlation between pressure set by the pump and both IRP and FR (rho > 0.9). As the diameter of the WCO increased, lower IRP and FR were observed with the pumps (p < 0.01). With SAPS, IRP was similar regardless of WCO, but FR was decreased with the increased diameter of WCO (p = 0.81 and p < 0.01, respectively). There was significantly higher IRP when using 11/13Fr UAS than 12/14Fr (p < 0.01)., Conclusion: IRP was higher with SAPS than automated pumps. ENDOMAT showed higher IRP than Thermedx when under 150 mmHg. IRP and FR increase with higher pump pressure and decrease with larger diameter WCO. Likewise, a larger UAS significantly reduced IRP., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: To compare the clinical efficacy and safety of single-use and reusable digital flexible ureteroscopy for the treatment of lower pole stones., Methods: We enrolled 135 patients underwent reusable flexible ureteroscopy (FURS) and 78 patients underwent single-use digital FURS. Demographic, clinical variables, anatomical parameters of the lower calyx and perioperative indicators were compared in the two groups., Results: Thirty-six patients in the infundibuloureter angle (IPA) < 45° subgroup had a mini-percutaneous nephrolithotomy (mini-PCNL), including 25 patients in the reusable FURS group and 11 patients in the single-use FURS group. The demographic and clinical variables in the two FURS groups were comparable. There was no statistical difference in the success rate of stone searching (P > 0.05). In terms of the success rate of lithotripsy, there was also no statistical difference in the IPA ≥ 45° subgroup (P > 0.05), whereas single-use FURS was superior in the IPA < 45° subgroup (χ2 = 6.513, P = 0.011). The length of the working fiber in the reusable FURS and single-use FURS groups was 3.20 ± 0.68 mm and 1.75 ± 0.47 mm, respectively (t = 18.297, P < 0.05). The use of a stone basket in the reusable FURS (31/135, 23.0%) was significantly higher than that in the single-use FURS (8/78, 10.3%) (χ2 = 5.336, P = 0.021). Compared with the reusable FURS group, the single-use FURS group had shorter operation times (P < 0.05) and higher stone-free rate (SFR) (χ2 = 4.230, P = 0.040). There was no statistical difference in the intraoperative transfer of mini-PCNL and postoperative complications between the two groups (P > 0.05)., Conclusions: Single-use and reusable FURS are alternative methods for removal of lower pole stones (i.e., 2 cm or less). Single-use FURS has a high success rate of lithotripsy, shorter operation time, and high stone-free rate., (© 2024. The Author(s).)

Purpose: To experimentally measure renal pelvis pressure (P RP ) in an ureteroscopic model when applying a simple hydrodynamic principle, the siphoning effect., Methods: A 9.5Fr disposable ureteroscope was inserted into a silicone kidney-ureter model with its tip positioned at the renal pelvis. Irrigation was delivered through the ureteroscope at 100 cm above the renal pelvis. A Y-shaped adapter was fitted onto the model's renal pelvis port, accommodating a pressure sensor and a 4 Fr ureteral access catheter (UAC) through each limb. The drainage flowrate through the UAC tip was measured for 60 s each run. The distal tip of the UAC was placed at various heights below or above the center of the renal pelvis to create a siphoning effect. All trials were performed in triplicate for two lengths of 4Fr UACs: 100 cm and 70 cm (modified from 100 cm)., Results: P RP was linearly dependent on the height difference from the center of the renal pelvis to the UAC tip for both tested UAC lengths. In our experimental setting, P RP can be reduced by 10 cmH 2 0 simply by lowering the distal tip of a 4 Fr 70 cm UAC positioned alongside the ureteroscope by 19.7 cm. When using a 4 Fr 100 cm UAC, P RP can drop 10 cmH 2 0 by lowering the distal tip of the UAC 23.3 cm below the level of the renal pelvis., Conclusion: Implementing the siphoning effect for managing P RP during ureteroscopy could potentially enhance safety and effectiveness., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Lithiasis is a common and recurrent disease. Flexible ureteroscopy (fURS) is the cornerstone of laser treatment of kidney stones. Kidney stones destruction requires its laser pulverization into small fragments in order to remove them through the ureter or improve their spontaneous expulsion along the urinary tract. However, most of the time, all the micro-fragments and dust created cannot be extracted using our surgical tools and may stay intra-renally at the end of the procedure. Adjuvant treatments (such as forced diuresis, inversion or mechanical pressure) were previously described to improve the expulsion of stone fragments after extra-corporeal shock wave lithotripsy. Nevertheless, the impact of adjuvant treatment after fURS remains unclear and mainly theoretical., Objective: The primary objective is to show that the injection of 40 mg of furosemide in slow intravenous during 10 min, after the procedure, increases the stone-free rate 3 months after a fURS for destruction of kidney stones with laser., Methods/design: The study will be a two-parallel group randomized, controlled, multicentric trial with a blinding evaluation. Nine French departments of urology will participate. Patients will be randomized in 2 groups: the experimental group (injection of 40 mg of furosemide at the end of the surgery) and a control one (usual care). Patients will be followed up for 3 months (± 2 weeks) after the surgery. Then, we will perform a low dose abdomino-pelvic CT scan. The primary outcome is the stone-free rate at 3 months. A centralized review of the images will be performed by two specialized radiologists, in a blind and crossed way to allow a homogenization of the results. The secondary outcomes will include the rate of early post-operative urinary tract infection (UTI), the evaluation of post-operative pain, and the safety of the use of furosemide in patients treated by fURS for renal stone laser destruction. As secondary objectives, it is also planned to look at the effect of the prescription of an alpha-blocker as usual treatment on stone-free rate and to assess the agreement between the imaging analysis of the urologist and the specialized radiologist., Discussion: Lithiasis is a public health problem. It affects about 10% of the general population. This prevalence is increasing (multiplied by 3 in 40 years), partly due to changes in the population's eating habits over the years. The lithiasis patient is a patient with a chronic disease requiring annual follow-up and who may suffer from multiple recurrences, with a recurrence rate at 5 years of 50%. Recurrences are partly due to residual fragments left in the kidneys at the end of the operation. Other risk factors for recurrence include dietary hygiene and the presence of an associated metabolic disease. The metabolic blood and urine tests recommended by the Association Française d'Urologie (AFU) can be used to manage these last two problems. As far as residual fragments are concerned, their presence leads to an early recurrence of stones because they form the bed for a new aggregation of crystals in the kidneys. Being able to reduce the rate of residual fragments in patients with the use of furosemide at the end of the intervention therefore seems essential in the management of recurrences in our patients. This will also improve our patients' quality of life. Indeed, lithiasis disease leads to chronic pain associated with acute pain that motivates consultations to the emergency for specialized management. This study is the first to evaluate the impact of forced diuresis with the use of furosemide on the stone-free rate after a fURS for destruction of kidney stone with laser., Trial Registration: ClinicalTrials.gov Identifier: NCT05916963 , first received: 22 June 2023. EU Clinical Trials Register EudraCT Number: 2022-502890-40-00., (© 2024. The Author(s).)

Upper urinary tract stones are a common urological disease that can be treated by flexible ureteroscopy (FURS) through the natural urinary tract, in addition to extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy. The advantages of FURS are less trauma, faster recovery, and fewer complications, while its disadvantages include poor results of lithotripsy and stone extraction when dealing with larger stones, and prolonged operation time. Over the last two decades, the emergence of new technologies such as FURS combined with negative pressure suction, robot-assisted FURS, and artificially intelligent FURS, coupled with improvements in laser technology (the use of thulium fiber lasers and the invention of single-use flexible ureteroscopes (su-fURS) suitable for primary level application, have significantly increased the global adoption of FURS. This surge in usage holds a promising future in clinical application, benefiting a growing number of patients with renal calculi. Accompanied by changes in technical concepts and therapeutic modalities, the scope of indications for FURS is broadening, positioning it as a potential primary choice for urolithiasis treatment in the future. This review outlines the progress in employing FURS for the treatment of renal calculi in order to generate insights for further research., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc.)

Purpose: Reusable flexible ureteroscopes may lose their mechanical functionality through overuse, which is known as "aging of the flexible ureteroscope." Although mechanical deterioration has been shown in several studies, the data about the effect of this situation on the efficacy and safety of retrograde intrarenal surgery (RIRS) are missing. The aim of our study was to evaluate the effect of the aging of flexible ureteroscopes on the efficacy and safety of RIRS. Methods: Patients who had undergone RIRS between 2017 and 2021 at a single center were retrospectively included in the study. Serial surgeries were performed using the same reusable flexible ureteroscope (Storz X 2 ) until it was broken or malfunctioned because of the aging process. Group 1 was formed by the first 10 cases on whom the flexible ureteroscopes were used, representing the youngest period of the instruments, whereas group 2 was composed of the last 10 cases on whom the flexible ureteroscopes were used, representing the oldest phase of the instruments. The operative and postoperative data-including the operation time, hospitalization time, intraoperative complications, postoperative complications, and stone-free rates-were compared between the two groups. Results: A total of five flexible ureteroscopes were included in the study. The number of cases for each flexible ureteroscope ranged between 87 and 133, with a median number of 107 cases. The demographic and clinical properties of patients in both groups were similar. The operation time, lasering time, and total laser pulse were similar between the groups. The stone-free rates in group 1 and group 2 were 82.0% and 78.0%, respectively ( p = 0.304). The complication rates were also similar between the groups ( p = 0.591). Conclusion: The aging of reusable flexible ureteroscopes did not negatively affect the efficacy and safety of RIRS. Therefore, surgeons may use the reusable types of flexible ureteroscopes until they are totally broken.