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

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

Risk factors and prediction model for postoperative complications in patients with struvite stones after percutaneous nephrolithotomy and flexible ureteroscopy.

OBJECTIVE: To analyze the risk factors for complications in patients with struvite stones following percutaneous nephrolithotomy (PCNL) or flexible ureteroscopy (fURS), and to establish a nomogram for postoperative complications in patients following PCNL. METHODS: A retrospective analysis was conducted on patients with struvite stones after PCNL and fURS at the Department of Urology, Peking University People's Hospital, from January 2012 to March 2022. The common pathogens and antimicrobial susceptibilities in preoperative midstream urine culture were analyzed. Logistic regression analyses were used to evaluate the risk factors. Receiver-operating characteristic (ROC) curve, calibration plots, and decision curve analysis (DCA) were used to assess the discrimination, accuracy, and practicability of the nomogram. RESULTS: 332 patients with struvite stones received one-stage PCNL or fURS, including 243 cases of PCNL and 89 cases of fURS. 72 patients (21.69%) developed postoperative complications. The most common pathogens in preoperative urine cultures were Escherichia coli, Proteus mirabilis, and Enterococcus faecalis. Multivariate logistic regression analysis showed that preoperative hemoglobin (OR = 0.981, P = 0.042), staghorn stone (OR = 4.226, P = 0.037), and positive preoperative midstream urine culture (OR = 2.000, P = 0.043) were independent risk factors for postoperative complications in patients following PCNL. The nomogram showed good performance in discrimination, accuracy, and applicability. CONCLUSION: Preoperative hemoglobin, staghorn stone, and positive preoperative midstream urine culture were independent risk factors for postoperative complications in patients with struvite stones following PCNL. A nomogram was developed to predict the probability of postoperative complications.

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

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

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

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

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

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

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

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

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

PURPOSE: The aim of the study was to evaluate illumination properties in an in-vitro kidney calyx model in saline. DESIGN AND METHODS: We evaluated a series of contemporary flexible ureteroscopes including the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, as well as OTU WiScope using a 3D-printed closed pink kidney calyx model, submerged in saline. A spectrometer was used for illuminance and color temperature measurements at different openings located at center (direct light), 45° (direct and indirect light) and 90°(indirect light) to the axis of the scope. RESULTS: Maximum illuminance was at the center opening for all scopes (range: 284 to 12,058 lx at 50% brightness and 454 to 11,871 lx at 100% brightness settings). The scope with the highest center illuminance (Flex-Xc) was 26 times superior to the scope with the lowest illuminance (Pusen 7.5Fr) at 100% brightness setting. For each scope, there was a peripheral illuminance drop ranging from - 43 to - 92% at 50% brightness and - 43% to - 88% at 100% brightness settings, respectively (all p < 0.01). Highest drop was for the P7 and the Pusen 9.2F. All scopes had illuminance skew, except the V3. All scopes had a warm color temperature. CONCLUSION: Illumination properties vary between ureteroscopes in an enclosed cavity in saline, and differs at center vs 45° and 90° positions within scopes. Peripheral illuminance drop can be as high as - 92%, which is undesirable. This may affect the choice of ureteroscope and light brightness settings used in surgery by urologists.

Is "Kidney Stone Calculator" efficient in predicting ureteroscopic lithotripsy duration? A holmium:YAG and thulium fiber lasers comparative analysis.

PURPOSE: This study aimed to evaluate the ability of Kidney Stone Calculator (KSC), a flexible ureteroscopy surgical planning software, to predict the lithotripsy duration with both holmium:YAG (Ho:YAG) and thulium fiber laser (TFL). METHODS: A multicenter prospective study was conducted from January 2020 to April 2023. Patients with kidney or ureteral stones confirmed at non-contrast computed tomography and treated by flexible ureteroscopy with laser lithotripsy were enrolled. "Kidney Stone Calculator" provided stone volume and subsequent lithotripsy duration estimation using three-dimensional segmentation of the stone on computed tomography and the graphical user interface for laser settings. The primary endpoint was the quantitative and qualitative comparison between estimated and effective lithotripsy durations. Secondary endpoints included subgroup analysis (Ho:YAG-TFL) of differences between estimated and effective lithotripsy durations and intraoperative outcomes. Multivariate analysis assessed the association between pre- and intraoperative variables and these differences according to laser source. RESULTS: 89 patients were included in this study, 43 and 46 in Ho:YAG and TFL groups, respectively. No significant difference was found between estimated and effective lithotripsy durations (27.37 vs 28.36 min, p = 0.43) with a significant correlation (r = + 0.89, p < 0.001). Among groups, this difference did not differ (p = 0.68 and 0.07, respectively), with a higher correlation between estimated and effective lithotripsy durations for TFL compared to Ho:YAG (r = + 0.95, p < 0.001 vs r = + 0.81, p < 0.001, respectively). At multivariate analysis, the difference was correlated with preoperative (volume > 2000 mm3 (Ho:YAG), 500-750 mm3 SV and calyceal diverticulum (TFL)), operative (fragmentation setting (p > 0.001), and basket utilization (p = 0.05) (Ho:YAG)) variables. CONCLUSION: KSC is a reliable tool for predicting the lithotripsy duration estimation during flexible ureteroscopy for both Ho:YAG and TFL. However, some variables not including laser source may lead to underestimating this estimation.

The optimal ratio of endoscope-sheath diameter with negative-pressure ureteral access sheath: an in vitro research.

PURPOSE: To maintain safe intrarenal pelvic pressure (IPP), the combination of flexible ureteroscope (fURS) and traditional ureteral access sheath (T-UAS) should maintain a basic rule that is the ratio of endoscope-sheath diameter (RESD) ≤ 0.75. However, the negative-pressure ureteral access sheath (NP-UAS) may break the rule of negative pressure suction. This study aimed to examine the effect of NP-UAS on IPP and flow rate (FR) with varying RESD. METHODS: In a 3D-printed renal model, flexible ureteroscopy lithotripsy (fURL) was replicated. Six sizes of fURS paired with 12Fr T-UAS and NP-UAS resulted in six distinct RESDs of 0.63, 0.78, 0.87, 0.89, 0.90, and 0.91. While the irrigation pressure (IRP) was set between 100 and 800 cmH2O and the sucking pressure (SP) was set between 0 and 800 cmH2O, the IPP and FR were measured in each RESD. RESULTS: NP-UASs can reduce the IPP and increase the FR at the same RESD compared to T-UASs. The IPP decreased with increasing SP with NP-UAS. When RESD ≤ 0.78, T-UAS and NP-UAS can maintain IPP < 40 cmH2O in most circumstances. When RESD = 0.87, it is challenging for T-UAS to sustain IPP < 40 cmH2O; however, NP-UAS can do so. When RESD ≥ 0.89, it is difficult to maintain an IPP < 40 cmH2O even with NP-UAS. CONCLUSION: NP-UAS can decrease IPP and increase FR compared with T-UAS. To maintain a safe IPP, it is recommended that RESD < 0.85 when utilizing NP-UAS.

Factors affecting the intraoperative calculi excretion during flexible ureteroscopy lithotripsy: an in vitro analysis.

OBJECTIVE: To explore the parameters influencing intraoperative calculi excretion (ICE) during flexible ureteroscopy lithotripsy (fURL) using in vitro simulation experiments. METHODS: 3D-printed human kidney models were used to simulate the elimination of gravel during fURL. The factors influencing the ICE during fURL were analyzed by comparing the effects of different degrees of hydronephrosis (mild, moderate, and severe), surgical positions (supine and lateral position), ratios of endoscope-sheath diameter (RESD) (0.625, 0.725, and 0.825), gravel sizes (0.50-1.00 mm, 0.25-0.50 mm, and 0.10-0.25 mm), and ureteral access sheaths (UASs) (traditional UAS and negative-pressure UAS) on ICE. RESULTS: The impacts of various UAS, RESD, degree of hydronephrosis, surgical positions, and gravel sizes on ICE were all significant (p < 0.05). We found no evidence of multicollinearity for all the independent variables, and the linear regression equation fitted as ICE ( g / min ) = 0.102 + 0.083 ∗ UAS grade - 0.050 ∗ RESD grade - 0.048 ∗ hydronephrosis grade + 0.065 ∗ position grade - 0.027 ∗ gravel size grade (R2 = 0.569). CONCLUSION: Employing negative-pressure UAS, smaller RESD, milder hydronephrosis, lateral position, and smaller gravel size contribute to improved ICE during fURL. Among them, the adoption of negative-pressure UAS had the most substantial effects.

Clinical comparative study of single-use and reusable digital flexible ureteroscopy for the treatment of lower pole stones: a retrospective case-controlled study.

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.

Comparison of percutaneous nephrolithotomy and flexible ureterorenoscopy in the treatment of single upper ureteral calculi measuring 1 to 2 centimeters: a retrospective study.

PURPOSE: To compare the efficacy and safety of micropercutaneous nephrolithotomy (MPCNL) and flexible ureteroscopy (FURS) in the treatment of single upper ureteral calculi measuring 1 to 2 centimeters. METHODS: This study is a retrospective analysis that combines a review of medical records with an outcomes management database. A total of 163 patients who underwent MPCNL and 137 patients who had FURS were identified between January 2017 and December 2021. Demographic data, operation time, hospitalization time, stone-free rate, and complication rate were collected and analyzed. RESULTS: Preoperative general data of sex, age, BMI, serum creatinine, time of stone existence, stone hardness, stone diameter, preoperative hydronephrosis, and preoperative infection of the MPCNL group have no statistically significant difference with that of the FURS group. All MPCNL or FURS operations in both groups were successfully completed without any instances of reoperation or conversion to another surgical procedure. Patients who underwent MPCNL had a considerably reduced operation time (49.6 vs. 72.4 min; P<0.001), but a higher duration of hospitalization (9.1 vs. 3.9 days; P<0.001) compared to those who underwent FURS. The stone-free rate in the MPCNL group was superior to that of the FURS group, with a percentage of 90.8% compared to 71.5% (P<0.001). There was no statistically significant disparity in the rate of complications between the two groups (13.5% vs. 15.3%; P = 0.741). CONCLUSION: Both MPCNL and FURS are viable and secure surgical choices for individuals with solitary upper ureteral calculi measuring 1 to 2 cm. The FURS procedure resulted in a shorter duration of hospitalization compared to MPCNL. However, it had a comparatively lower rate of successfully removing the stones and required a longer duration for the operation.There were no substantial disparities observed in the complication rate between the two groups.FURS is the preferable option for treating uncomplicated upper ureteral calculi, whereas MPCNL is the preferable option for treating complicated upper ureteral calculi.Prior to making treatment options, it is crucial to take into account the expertise of surgeons, the quality of the equipment, and the preferences of the patient. TRIAL REGISTRATION: No.

Treatment of ureteropelvic junction obstruction in patients with renal calculi via laparoscopic pyeloplasty and flexible vacuum-assisted ureteral access sheath ureteroscopy: a multicenter retrospective observational study.

BACKGROUND: Ureteropelvic junction obstruction (UPJO) is a common obstructive disease of the urinary tract. UPJO patients commonly exhibit coexistent renal calculi. The main aim of therapy is to relieve the obstruction and remove the stones at the same time. METHODS: This retrospective study included 110 patients diagnosed with UPJO coexisting with multiple renal calculi at Shanxi Bethune Hospital and the First Hospital of Shanxi Medical University between March 2016 and January 2022. Patients were divided according to the methods used for dealing with UPJO and renal calculi. In Group A, patients underwent traditional open pyeloplasty and pyelolithotomy. In Group B, patients underwent percutaneous nephrolithotomy first and then laparoscopic pyeloplasty. In Group C, patients underwent flexible cystoscopy to remove stones and then laparoscopic pyeloplasty. In Group D, patients underwent flexible vacuum-assisted ureteral access sheath (FV-UAS)assisted flexible ureteroscopy (f-URS) and underwent laparoscopic pyeloplasty. The stones were broken up using a holmium laser. The pyeloplasty success rate, stone clearance rate, operation time, bleeding amount, complication occurrence rate, postsurgical pain, length of stay, and hospitalization cost were compared between the groups. The follow-up period was at least 2 years. RESULTS: The use of f-URS and the FV-UAS, significantly increased the renal stone clearance rate and significantly reduced the complication incidence and operation time in UPJO patients with multiple coexisting renal calculi. CONCLUSIONS: Laparoscopic pyeloplasty combined with f-URS and FV-UAS is safe and effective for treating UPJO in patients complicated by renal caliceal stones. TRIAL REGISTRATION: Retrospectively registered.

A retrospective comparison of Sun's tip-flexible semirigid ureterorenoscopy, super-mini percutaneous nephrolithotomy and flexible ureteroscopy applied to treat upper urinary tract calculi.

BACKGROUND: This retrospective study was conducted to compare the safety and efficacy of Sun's tip-flexible semirigid ureterorenoscopy (tf-URS), super-mini percutaneous nephrolithotomy (SMP) and flexible ureteroscopy (FURS) in treating upper urinary tract calculi, including upper ureteral or renal calculi. METHODS: We included patients with upper ureteral calculi or renal calculi 1.0-2.0 cm in size, who underwent tf-URS, SMP or FURS, respectively. The indicators reflecting safety and efficacy were compared among the three surgical techniques. RESULTS: SMP presented with higher single stone crushing success rate, but longer operation time and postoperative hospital stay, more blood loss, and higher postoperative pain score compared with FURS and tf-URS (P < 0.05). The hospitalization cost of tf-URS group was lower than that of SMP and FURS groups (P < 0.05). The incidence of postoperative fever in tf-URS group was significantly higher than that in SMP group (P < 0.05). No significant difference was found in mucosal injury, perirenal hematoma, and stone-free rate at 3 months after surgery (P > 0.05). CONCLUSIONS: tf-URS and FURS have the advantages in minimal invasion, hospitalization cost, patient comfort, and hospital stay while SMP has higher stone-free rate. These three surgical techniques are safe, reliable and complementary, which should be selected according to the actual situation.

Flexible Ureteroscopy with a Tip-Flexible Pressure-Controlling Ureteral Access Sheath for Renal Stones in Children.

INTRODUCTION: The aim of this study was to evaluate the safety and efficacy of flexible ureteroscopy using a tip-flexible pressure-controlling ureteral access sheath (TFPC-UAS) for renal stones in children. METHODS: Consecutive patients aged 5-18 years with renal stones of diameter 1-3 cm were enrolled between January 2022 and November 2023 at Ganzhou People's Hospital. The patients were treated with flexible ureteroscopy using the TFPC-UAS. The renal pelvic pressure (RPP) parameters were set as follows: control value at -10 mm Hg to 5 mm Hg, warning value at 20 mm Hg, and limit value at 30 mm Hg. The infusion flow rate was set to 100-120 mL/min. A holmium laser (276 µm) was used to fragment the stone at 2.0-2.5 J/pulse with a frequency of 20-30 pulses/s. The cases were analyzed for RPP, operative time, stone-free rate, and complications. RESULTS: A total of 21 consecutive patients were included. Two patients were switched to percutaneous nephrolithotomy owing to sheath placement failure. The RPP was -4.6 ± 2.1 mm Hg. The mean operative time was 56.5 ± 17.1 min. The postoperative hospitalization time was 1.5 ± 0.3 days. The stone-free rates at 1 day and 1 month after surgery were 81.0% and 85.7%, respectively. Residual stones in 2 patients were cleared after extracorporeal shockwave lithotripsy. Three cases of Clavien I complications and one case of Clavien II complications occurred. No major complications (Clavien grade III-V) were observed. CONCLUSIONS: Flexible ureteroscopy with a TFPC-UAS is safe and effective for renal stones in children.

Flexible ureteroscopy with novel flexible ureteral access sheath versus mini-percutaneous nephrolithotomy for treatment of 2-3 cm renal stones.

OBJECTIVES: To assess and compare the effectiveness and safety of flexible ureteroscopy (f-URS) with a novel flexible ureteral access sheath (f-UAS) versus mini-percutaneous nephrolithotripsy (mini-PCNL) in treating 2-3 cm renal stones. METHODS: Retrospectively analyzed consecutive cases that underwent f-URS with f-UAS (12/14 Fr) from January 29, 2022, to November 30, 2022. Consecutive cases that underwent mini-PCNL (18 Fr) from June 5, 2021, to January 26, 2022, were selected as controls. The f-UAS is a novel device with a 10 cm anterior tip that passively bends along with the f-URS to enter the renal calyx. We analyzed demographic characteristics, stone parameters, operative time, stone-free rates (SFR), hospitalization time, and complication. RESULTS: A total of 96 consecutive cases that underwent f-URS with f-UAS and 96 consecutive cases that underwent mini-PCNL were included in the study. There were no significant differences between the two groups in terms of operative time (p = 0.06), stone volume clearance (p = 0.533) and complete SFR (p = 0.266) on the first postoperative day or residual Stone after 1 month (p = 0.407). We observed a significantly shorter postoperative hospital stay (1.4 days vs. 2.1 days; p < 0.001) and a lower decrease in hemoglobin levels (0.39 g/dL vs. 0.68 g/dL; p < 0.001) in the f-UAS group. The mini-PCNL group had a significantly higher overall complication rate (13.5%) compared with the f-UAS group (5.2%; p = 0.048). CONCLUSIONS: In the treatment of 2-3 cm renal stones, f-URS with a novel f-UAS may provide a superior alternative to mini-PCNL, potentially challenging its established status.

International Alliance of Urolithiasis guideline on retrograde intrarenal surgery.

OBJECTIVES: To set out the second in a series of guidelines on the treatment of urolithiasis by the International Alliance of Urolithiasis that concerns retrograde intrarenal surgery (RIRS), with the aim of providing a clinical framework for urologists performing RIRS. MATERIALS AND METHODS: After a comprehensive search of RIRS-related literature published between 1 January 1964 and 1 October 2021 from the PubMed database, systematic review and assessment were performed to inform a series of recommendations, which were graded using modified GRADE methodology. Additionally, quality of evidence was classified using a modification of the Oxford Centre for Evidence-Based Medicine Levels of Evidence system. Finally, related comments were provided. RESULTS: A total of 36 recommendations were developed and graded that covered the following topics: indications and contraindications; preoperative imaging; preoperative ureteric stenting; preoperative medications; peri-operative antibiotics; management of antithrombotic therapy; anaesthesia; patient positioning; equipment; lithotripsy; exit strategy; and complications. CONCLUSION: The series of recommendations regarding RIRS, along with the related commentary and supporting documentation, offered here should help provide safe and effective performance of RIRS.

A single center comparative study of two single use digital flexible ureteroscopy in the management of renal stones less than 2 cm.

PURPOSE: For renal stones < 2 cm, guidelines recommend the use of retrograde intrarenal surgery as a first line treatment option. Many available single use flexible ureteroscopy were found. We aim to compare the effectiveness of two single use flexible ureteroscopy; Pusen Uscope 3011 versus LithoVue in the management of renal stones less than 2 cm. METHODS: Our study prospectively included 60 patients equally divided in to two groups: Pusen group and LithoVue group during the period from June 2020 to June 2021. The included patients were above 18 years old. Perioperative details as operative time, fluoroscopy time, hospital stay, and complications were recorded. Stone free rate was assessed. Base purchase cost was also compared. RESULTS: There was no statistically significant difference between the two groups regarding age, gender, and body mass index (BMI), stones size, side, number and location. The perioperative evaluation and outcome had no statistically significant differences between the two groups regarding the operative time, hospital stay, access sheath use, and stone free rate or radiation exposure. Among all cases, we had 49 cases (81.6%) with no postoperative complications (21 cases for Pusen group and 28 cases for LithoVue group). The incidence of postoperative complications was significantly higher among Pusen group than LithoVue group (p = 0.02). Initial purchase cost for both FURS had no significant difference (P = 0.86). CONCLUSION: RIRS can be performed effectively with Pusen 3011 and LithoVue single use flexible ureteroscopy in patients diagnosed with renal calculi < 2 cm with superior outcomes with LithoVue.

Pattern of key opinion leaders talks at major international urological meetings reflects the main differences in flexible ureteroscopy and PCNL diffusion.

OBJECTIVE: To analyze the pattern of speaker activity related to both flexible ureteroscopy (fURS) and percutaneous nephrolithotomy (PCNL) during plenary sessions at the main (endo)urological international meetings over the last 10 years. METHODS: We reviewed the meeting programs of the main endourological international meetings (EAU, AUA, WCE, and SIU) during 2011-2019. We detected all invited speakers at plenary sessions regarding fURS or PCNL. The proportion of fURS and PCNL talks was evaluated yearly during the study period. In order to analyze plenary session speaker composition, we estimated and compared the mean number of talks per speaker according to surgical technique. We also analyzed possible differences in age distribution according to the topic of the talk as well as the presence of young (i.e., < 45 years) speakers. Data were analyzed using descriptive statistics. RESULTS: During the last 10 years, a total of 498 plenary talks were found. Of those, 260 (52.2%), 211 (42.4%), and 27 (5.4%) discussed PCNL, fURS, or both, respectively. PCNL was more frequently discussed at the beginning and the end of the study period. Mean [SD] number of talks per speaker was higher for PCNL (2.9 [3.4] vs 1.6 [1.4], p < 0.001), meaning that a wider variety of speakers was invited to give fURS talks. Speakers discussing fURS were younger (median [interquartile range, IQR] age 48 [44-56] vs 52 [47-60] years, p < 0.001), and a higher proportion of young speakers was observed in the fURS group (26% vs 15% p < 0.001). PCNL speakers were more commonly discussing fURS than fURS speakers discussing PCNL (23% vs 17%, p = 0.43). CONCLUSIONS: We found a wider variety of speakers at fURS plenary sessions as compared to PCNL ones. It is easier and quicker to become an internationally recognized expert in the field of fURS rather than PCNL. PCNL speakers were able to master fURS more frequently than the other way around.

Intrarenal pressure study using 7.5 French flexible ureteroscope with or without ureteral access sheath in an ex-vivo porcine kidney model.

INTRODUCTION: 7.5F digital fURS and 9.5/11.5F ureteral access sheaths (UAS), both conventional (cUAS) and vacuum-assisted (vaUAS), are commercially available. Irrigation increases intrarenal pressure (IRP). This study analyzes the IRP with various irrigation rates using 7.5F fURS without UAS or with either cUAS or vaUAS in an ex-vivo porcine model. Pyelo-tubular backflow was also studied during these experiments. MATERIALS AND METHODS: 11 porcine kidneys were used. 7.5F digital fURS was tested without UAS and with 9.5/11.5F cUAS and vaUAS. 6F pressure monitor catheters were placed into the upper and lower calyces. IRPs were recorded under different irrigation rates. When vaUAS was used, the air vent was either open or closed. 300 mmHg aspiration pressure was chosen. Lastly, contrasted irrigation fluid was delivered until IRP reached above 30 mmHg. Fluoroscopy images were obtained at 5 mmHg intervals over this threshold to study the pyelo-tubular backflow. RESULTS: Using cUAS, IRP reached 30 mmHg with irrigation rates between 60 and 70 cc/min. Using vaUAS with vent closed, IRP never exceeded 10 mmHg with irrigation up to 120 cc/min. vaUAS with vent open performed marginally better than cUAS. fURS without UAS performed better than cUAS. Pyelo-tubular backflow became prominent at 40 mmHg. CONCLUSION: In an ex-vivo porcine model, 7.5F fURS could be used safely without UAS with irrigation rates up to 120 cc/min. The safety margin dropped to 60-70 cc/min with cUAS. vaUAS with vent closed maintained IRP < 10 mmHg with irrigation rates up to 120 cc/min. Pyelo-tubular backflow was observed with IRP > 35 mmHg.