Japanese survey of perioperative complications and ureteral stricture after ureteroscopy with laser lithotripsy for upper urinary tract stones in multicenter collaborative study.

OBJECTIVES: This study aimed to investigate perioperative complications and the details of postoperative ureteral stricture after ureteroscopy with laser lithotripsy (URS-L) for upper urinary tract stones in Japan. METHODS: Patient data on intra- and postoperative complications after ureteroscopy using URS-L were retrospectively collected from multiple centers in Japan between April 2017 and March 2020 with the cooperation of the Japanese Society of Endourology and Robotics. Data included the number of patients undergoing URS-L, number and type of intra- and postoperative complications, and detailed characteristics of postoperative ureteral stricture. RESULTS: In total, 14 125 patients underwent URS-L over 3 years at 82 institutions. Annual URS-L numbers gradually increased from 4419 in 2017, to 4760 in 2018, and 4946 in 2019. The total complication rate was 10.5%, which was divided into intra-operative complications in 1.40% and postoperative complications in 9.18%. The annual incidences of intra- and postoperative complications were not significantly different from year to year (p = 0.314 and p = 0.112). Ureteral perforation, ureteral avulsion, and the intra-operative conversion rate were 1.35%, 0.03%, and 0.02%, respectively. Fever >38°C, septic shock, blood transfusion, and postoperative mortality were 7.44%, 0.81%, 0.07%, and 0.04%, respectively. Ureteral stricture occurred in 0.8% of cases. The median length of stricture site was 10.0 mm and the success rate of stricture treatment was 54.6%. CONCLUSION: Although URS-L utilization has increased in Japan, the annual complication rate has remained steady. Although URS-L is a useful and less invasive procedure, devastating complications can still occur.

Comparing Same-Sitting Bilateral vs Unilateral Retrograde Intrarenal Surgery in the Elderly.

OBJECTIVE: To compare same-sitting bilateral vs unilateral retrograde intrarenal surgery (RIRS) in elderly patients, focusing on postoperative complications and stone-free rates (SFR). METHODS: Data from 2 multicenter databases, FLEXible ureteroscopy Outcomes Registry (FLEXOR) (unilateral RIRS) and same sitting bilateral-retrograde intrarenal surgery (SSB-RIRS) (bilateral RIRS), were analyzed, considering only patients aged 70+ with preoperative computed tomography. Patients were categorized into Group 1 (bilateral RIRS) and Group 2 (unilateral RIRS). Follow-up included imaging assessments and secondary treatments as needed. RESULTS: Group 1 included 146 patients, while group 2 had 495. Group 1's patients were slightly older and had a higher prevalence of recurrent stone formation. Group 2 often underwent RIRS for incidental stones. Group 1 had larger and more pelvic stones. Laser lithotripsy and total operation times were significantly longer in Group 1. Group 2 had significantly higher overall stone-free rates, although there were no significant differences in ancillary procedures for residual fragments. Group 1 experienced more pelvicalyceal injuries needing stenting, postoperative fever, and post-op hematuria not requiring transfusion. CONCLUSION: In conclusion, bilateral RIRS can be carefully considered in elderly patients. Preoperative counseling is essential for both primary and repeat RIRS procedures, and further research is needed to optimize instrument and laser strategies for better outcomes in elderly RIRS patients.

In vitro comparison of simulated intrapelvic pressure in an artificial kidney model during retrograde intrarenal surgery among various single-use ureteroscopes.

OBJECTIVES: This study compares intrapelvic pressure (IPP) during retrograde intrarenal surgery with various single-use flexible ureteroscopes (f-URS) in an artificial kidney model. METHODS: We created an artificial kidney model with a pressure sensor using a bladder evacuation device. The model was completely closed and the only backflow was on the side of the ureteroscope inside the ureteral access sheath (UAS). We tested five single-use f-URSs (LithoVue, Wiscope, PU3022A, PU3033A, and AXIS) with six different types of UAS (9.5/11.5-14/16 Fr). Using the automatic irrigation system, 30 s of irrigation was performed at various pressures (40-180 mmHg) and steady-state IPP was recorded. IPP was compared between the five single-use f-URSs. IPP cutoff value was determined at 30 mmHg. The diameter of the endoscope tip and the curved and shaft parts were also measured and recorded. RESULTS: The diameters of all parts were significantly different between single-use f-URSs. The maximum IPP tended to be higher in ureteroscopes with larger diameters of the proximal parts (curved part/shaft part). In LithoVue and Uscope PU3022A f-URSs, the maximum IPP did not exceed 30 mmHg when UAS ≥12/14 Fr was used. In AXIS and Wiscope f-URSs, it did not exceed the cutoff value when the UAS ≥11/13 Fr was used. In Uscope PU3033A f-URS, it did not exceed 30 mmHg when the UAS ≥10/12 Fr was used. CONCLUSIONS: Maximum IPP tended to be higher in f-URSs with larger diameters of the proximal part and the appropriate size of the UAS differed between various single-use f-URSs.

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

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

Models to predict the surgical outcome of mini-ECIRS (endoscopic combined intrarenal surgery) for renal and/or ureteral stones.

To establish a safer and more efficient treatment strategy with mini-endoscopic combined intrarenal surgery (ECIRS), the present study aimed to develop models to predict the outcomes of mini-ECIRS in patients with renal and/or ureteral stones. We retrospectively analysed consecutive patients with renal and/or ureteral stones who underwent mini-ECIRS at three Japanese tertiary institutions. Final treatment outcome was evaluated by CT imaging at 1 month postoperatively and stone free (SF) was defined as completely no residual stone or residual stone fragments ≤ 2 mm. Three prognostic models (multiple logistic regression, classification tree analysis, and machine learning-based random forest) were developed to predict surgical outcomes using preoperative clinical factors. Clinical data from 1432 ECIRS were pooled from a database registered at three institutions, and 996 single sessions of mini-ECIRS were analysed in this study. The overall SF rate was 62.3%. The multiple logistic regression model consisted of stone burden (P < 0.001), number of involved calyces (P < 0.001), nephrostomy prior to mini-ECIRS (P = 0.091), and ECOG-PS (P = 0.110), wherein the area under the curve (AUC) was 70.7%. The classification tree analysis consisted of the number of involved calyces with an AUC of 61.7%. The random forest model showed that the top predictive variable was the number of calyces involved, with an AUC of 91.9%. Internal validation revealed that the AUCs for the multiple logistic regression model, classification tree analysis and random forest models were 70.4, 69.6 and 85.9%, respectively. The number of involved calyces, and a smaller stone burden implied a SF outcome. The machine learning-based model showed remarkably high accuracy and may be a promising tool for physicians and patients to obtain proper consent, avoid inefficient surgery, and decide preoperatively on the most efficient treatment strategies, including staged mini-ECIRS.

PCNL vs RIRS in management of stones in calyceal diverticulum: outcomes from a global multicentre match paired study that reflects real world practice.

INTRODUCTION: Calyceal diverticulum (CD) is the outpouching of a calyx into the renal parenchyma, connected by an infundibulum. Often associated with recurrent stones, common surgical options include percutaneous nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS). We aim to present the real-world practises and outcomes comparing both approaches and the technical choices made. MATERIALS AND METHODS: Retrospective data including 313 patients from 11 countries were evaluated. One hundred and twenty-seven underwent mini-PCNL and one hundred and eighty-six underwent RIRS. Patient demographics, perioperative parameters, and outcomes were analysed using either T test or Mann-Whitney U test. Categorical data between groups were analysed using the Chi-squared test. Propensity score matching (PSM) was performed matching for baseline characteristics. Subgroup analyses for anomalous/malrotated kidneys and difficult diverticulum access were performed. RESULTS: After PSM, 123 patients in each arm were included, with similar outcomes for stone-free rate (SFR) and complications (p < 0.001). Hospitalisation was significantly longer in PCNL. Re-intervention rate for residual fragments (any fragment > 4 mm) was similar. RIRS was the preferred re-intervention for both groups. Intraoperative bleeding was significantly higher in PCNL (p < 0.032) but none required transfusion. Two patients with malrotated anatomy in RIRS group required transfusion. Lower pole presented most difficult access for both groups, and SFR was significantly higher in difficult CD accessed by RIRS (p < 0.031). Laser infundibulotomy was preferred for improving diverticular access in both. Fulguration post-intervention was not practised. CONCLUSION: The crux lies in identification of the opening and safe access. Urologists may consider a step-up personalised approach with a view of endoscopic combined approach where required.

Quality of life after urinary stone surgery based on Japanese Wisconsin Stone Quality of Life questionnaire: multicenter analysis from SMART study group.

We aimed to evaluate the impact of surgical treatment for urinary stones on perioperative health-related quality of life (HRQOL) using the Japanese Wisconsin Stone Quality of Life questionnaire (J-WISQOL), an HRQOL measure designed for patients with urinary stones. This study prospectively enrolled 123 patients with urinary stones who visited three academic hospitals for stone treatment. The participants completed the J-WISQOL within 4 weeks before and after the urinary stone treatment. Treatments included shock wave lithotripsy (SWL), ureteroscopy lithotripsy, and endoscopic combined intrarenal surgery. J-WISQOL was assessed for age, stone size and location, type of treatment, stone-free status, postoperative ureteral stent placement, hospital stay, and complications in all patients. Patients with stones in the ureter had significantly greater social impact D1 and disease impact D3 than those with stones in the kidney. In a comparison of pre- and postoperative J-WISQOL, patients without postoperative ureteral stent placement scored significantly higher on social impact D1 and disease impact D3. Patients with shorter hospital stays had significantly higher social impact D1 and disease impact D3 (p < 0.001) than those with longer hospital stays. SWL significantly improved the total score, social impact D1, and disease impact D3 compared with other treatments. Perioperative HRQOL in patients with urinary stones is particularly affected by the type of treatment, ureteral stent placement, and hospital stay, which should be considered in surgical selection and patient decision-making.

Application of ultrasound imaging in the treatment of urinary tract stones.

Urinary tract stones are a common clinical condition that affect millions of individuals worldwide. The management of these stones has evolved significantly over the past 70 years, and ultrasound imaging has emerged as a valuable tool for diagnosis, treatment planning, and follow-up. This review aims to provide an overview of the application of ultrasound imaging in the treatment of urinary tract stones, highlighting its advantages, limitations, and current advancements in the field.

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

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

Influence of pre-stenting on RIRS outcomes. Inferences from patients of the Global Multicentre Flexible Ureteroscopy Outcome Registry (FLEXOR).

BACKGROUND: Retrograde Intrarenal Surgery (RIRS) is recommended as an alternative to percutaneous nephrolithotomy for stones up to 2 cm. Pre-stenting before RIRS remains controversial with various studies differing in outcomes and recommendations. We aim to understand how pre-stenting influences surgical outcomes. METHODS: A number of 6579 patients from the TOWER group registry were divided into pre-stented (group 1) and non-pre-stented groups (group 2). Patients aged ≥18 years old, with normal calyceal anatomy were enrolled. Patients with ureteric stones, anomalous kidneys, bilateral stones, planned for ECIRS were excluded. RESULTS: Patients are homogeneously distributed in both groups (3112 vs. 3467). The predominant indication for pre-stenting was symptom relief. Overall stone size was comparable, whilst group 1 had a significantly more multiple (1419 vs. 1283, P<0.001) and lower-pole (LP) stones (1503 vs. 1411, P<0.001). The mean operative time for group 2 was significantly longer (68.17 vs. 58.92, P<0.001). Stone size, LP stones, age, recurrence and multiple stones are contributing factors for residual fragments at the multivariable analysis. The incidence of postoperative day 1 fever and sepsis was significantly higher in group 2, indicating that pre-stenting is associated with a lower risk of post-RIRS infection and a lower overall complications rate (13.62% vs. 15.89%) (P<0.001). CONCLUSIONS: RIRS without pre-stenting can be considered safe without significant morbidity. Multiple, lower-pole and large stone is a significant contributor towards residual fragments. Patients who were not pre-stented had significantly higher but low-grade complications, especially for lower pole and large volume stones. While we do not advocate routine pre-stenting, a tailored approach for these patients should include proper counselling regarding pre-stenting.

Do Hounsfield Units have any significance in predicting intra- and postoperative outcomes in retrograde intrarenal surgery using Holmium and Thulium fiber laser? Results from the FLEXible ureteroscopy Outcomes Registry (FLEXOR).

PURPOSE: To evaluate outcomes of flexible ureteroscopy for renal stones by comparing hard versus soft stones based on their attenuation on computed tomography (Hounsfield Units-HU). METHODS: Patients were divided into two groups according to the type of laser employed [Holmium:YAG (HL) or Thulium fiber laser (TFL)]. Residual fragments (RF) were defined as > 2 mm. Multivariable logistic regression analysis was performed to evaluate factors associated with RF and RF needing further intervention. RESULTS: 4208 patients from 20 centers were included. In whole series, age, recurrent stones, stone size, lower pole stones (LPS), and multiple stones were predictors of RF at multivariable analysis and LPS and stone size with RF requiring further treatment. HU and TFL were associated with lesser RF and RF requiring an additional treatment. In HU < 1000 stones, recurrent stones, stone size, and LPS were predictors of RF at multivariable analysis, whereas TFL was less likely associated with RF. Recurrent stones, stone size, and multiple stones were predictors of RF requiring further treatment, while LPS and TFL were associated with lesser RF requiring further treatment. In HU ≥ 1000 stones, age, stone size, multiple stones, and LPS were predictors of RF at multivariable analysis, while TFL was less likely associated with RF. Stone size and LPS were predictors of RF requiring further treatment, whereas TFL was associated with RF requiring further treatment. CONCLUSION: Stone size, LPS, and use of HL are predictors of RF after RIRS for intrarenal stones regardless of stone density. HU should be considered an important parameter in predicting SFR.

Evaluation of sexual function after dutasteride treatment in patients with once-negative prostate biopsy and benign prostate hyperplasia.

INTRODUCTION: Patients with benign prostatic hyperplasia are usually treated with 5α-reduced inhibitors (5ARIs) such as finasteride and dutasteride. However, studies on the influence of 5ARIs on sexual function have been controversial. In this study, we evaluated the impact of dutasteride treatment for erectile function in patients with once-negative prostate biopsy and benign prostate hyperplasia. PATIENTS AND METHODS: 81 patients with benign prostate hyperplasia were enrolled in a one-armed prospective study. They were administrated 0.5 mg/day of dutasteride for 12 months. Patient characteristics and changes of International Prostate Symptom Score (IPSS) and International Index of Erectile Function (IIEF)-15 scores at baseline and 12 months after dutasteride administration were examined. RESULTS: The mean ± standard deviation (SD) age of the patients was 69.4 ± 4.9 years and the prostate volume was 56.6 ± 21.3 mL, respectively. The mean ± SD prostate volume and PSA levels were decreased 25.0 and 50.9%, respectively, after 12 months of dutasteride administration. IPSS total, voiding subscore, storage subscore, and quality of life score significantly improved after 12 months of dutasteride administration. No statistically significant change in IIEF-total score from 16.3 ± 13.5 to 18.8 ± 16.0 (p = 0.14), IIEF-EF score from 5.1 ± 6.9 to 6.4 ± 8.3 (p = 0.13) were observed. There was no decrease in erectile function severity. CONCLUSION: Twelve months administration of dutasteride for patients with BPH improved urinary function and did not increase the risk of sexual dysfunction.

Impact of pelvicalyceal anatomical variation on surgical outcomes of endoscopic combined intrarenal surgery.

Objectives: The objective of this work is to investigate the impact of the pelvicalyceal anatomical system (PCS) on calyceal stone formation and surgical outcomes of endoscopic combined intrarenal surgery (ECIRS) for renal and/or proximal ureteral stones with a diameter >15 mm. Patients and methods: PCS was classified as Type I (single pelvis) or Type II (divided pelvis) according to the simple anatomical Takazawa classification. Using prospectively collected data from January 2016 to April 2020, 219 patients were retrospectively reviewed. After excluding patients who underwent a staged procedure, had hydronephrosis greater than grade 2, prior nephrostomy tubes, and failed to access the renal collecting system, 115 patients (Type I: 81, Type II: 34) were included, and the distribution of calyceal stones and surgical outcomes in ECIRS were compared between Types I and II PCS. Results: The median number of renal stone calyces in the Type II group was significantly more than that in the Type I group (p = 0.016). In particular, the Type II group possessed more upper stone calyces. Multivariate logistic regression analysis revealed that Type II PCS was associated with an increased odds ratio (OR) for the presence of upper stone calyces (OR: 2.93, p = 0.018). The stone-free (SF) status at 1 month after surgery, confirmed by abdominal plain radiography, was significantly higher in the Type I group compared with that in Type II (67.9% vs. 39.4%, respectively; p = 0.006). The requirement for additional surgical interventions was significantly higher in the Type II group compared with that in Type I (35.4% vs. 7.4%, respectively; p < 0.001). Multivariate analysis revealed that the number of stone calyces (OR: 4.26; p = 0.001) and Type II PCS (OR: 3.43; p = 0.009) were independent predictors of residual stones after ECIRS. Conclusion: We first revealed that the anatomic properties of PCS play a role in both upper calyceal stone formation and in the success of the ECIRS procedure. Because the SF rate in Type II PCS was significantly lower than that in Type I PCS, additional percutaneous nephrolithotomy tracts might be required, even for ECIRS.

Dynamic Changes in Fluid Temperatures during Laser Irradiation Using Various Laser Modes: A Thermography-Based In Vitro Phantom Study.

The differences in dynamic thermal changes during laser lithotripsy between various laser pulse modes are unclear. We used thermography to evaluate the temporal changes in high-temperature areas during laser activation in order to compare different laser pulse modes. An unroofed artificial kidney model was used for the experiments. The laser fired for 60 s with a laser setting of 0.4 J/60 Hz in the following four different laser pulse modes without saline irrigation: short pulse mode (SPM), long pulse mode (LPM), virtual basket mode (VBM) and Moses mode (MM). Using the first 30 s of moving images, we compared the ratio of a high-temperature area of >43 °C to the total area every 5 seconds. The dynamic changes in fluid temperatures were shown to be different between the laser pulse modes. The extent of the high-temperature areas during the laser activation was large in the LPM and MM compared with the SPM and VBM. While the high-temperature areas expanded in an anterior direction in the early laser irradiation period using the LPM, they spread in a posterior direction in the early laser activation period using the MM. Although only the temperature profile in one specific plane was investigated, these results are considered useful for preventing thermal injuries during retrograde intrarenal surgeries.

Impact of Vacuum-Assisted Mini-Endoscopic Combined Intrarenal Surgery for Staghorn Stones: Analysis of Perioperative Factors of Postoperative Fever and Stone-Free Status.

Background and Objective: This retrospective cohort study aimed to evaluate the clinical outcomes of vacuum-assisted mini-endoscopic combined intrarenal surgery (vmECIRS) for staghorn stones. Patients and Methods: We analyzed a total of 61 cases treated with initial vmECIRS using 14F/16F ClearPetra® percutaneous sheaths for staghorn stones. We primarily measured complications and stone-free rates (SFRs) to evaluate the safety and efficiency of vmECIRS. In addition, pre- and intraoperative factors in patients who experienced postoperative fever >38°C and achieved an initial stone-free status were evaluated. Results: The percentages of staghorn stones were 36.1% and 63.9% for complete and partial stones, respectively. The median stone volume was 8.48 cm3. The median operation time was 117 minutes, and the mean number of procedures was 1.54. Regarding postoperative complications, postoperative fever >38°C was reported in 18 patients (29.5%). The initial and final SFRs were 50.8% and 91.8%, respectively. Among patients with emerging fever >38°C, positive urine culture was the only significant risk factor in the multivariate analysis (odds ratio [OR], 7.500; 95% confidence interval [CI], 1.772-31.751; p = 0.006). Moreover, for achieving initial stone-free status, body mass index and stone volume were significant risk factors in the multivariate analysis (OR, 0.872; 95% CI, 0.776-0.980; p = 0.021; and OR, 0.882; 95% CI, 0.784-0.994; p = 0.039, respectively). Conclusions: These findings suggest that vmECIRS is safe and effective for treatment of staghorn stones. Although current guidelines suggest that percutaneous nephrolithotomy is the gold standard surgical technique for staghorn stones, vmECIRS could also be a treatment strategy. The Clinical Trial Registration number (ID: 2022-05-17-1).

Pelvicalyceal anatomy on the accessibility of reusable flexible ureteroscopy to lower pole calyx during retrograde intrarenal surgery.

OBJECTIVE: This study aimed to evaluate the pelvicalyceal anatomy on accessibility of reusable flexible ureteroscopy (fURS) to the lower pole calyx during retrograde intrarenal surgery (RIRS). METHODS: Here, 854 patients with ureteral or kidney stones with access to a renal collecting system using reusable fURS were classified into either the accessible group, in whom the deepest lower pole calyces could be touched; and the inaccessible group, in whom the deepest lower calyces could not be touched. We measured the infundibulopelvic angle (IPA), infundibular width (IW), infundibular length (IL), and calyceal pelvic height (CPH) using retrograde pyelograms and performed intergroup comparisons. RESULTS: The median IPA, IW, IL, and CPH in the accessible and inaccessible group were 60.5° and 45.6° (p < 0.001), 10.8 and 9.4 mm (p < 0.001), 33.2 and 36.4 mm (p < 0.001), and 25.9 and 30.9 mm (p < 0.001), respectively. IPA (OR 0.963, 95% CI 0.952-0.974, p < 0.001) and IW (OR 0.519, 95% CI 0.331-0.816, p = 0.004) were significant risk factors of renal pelvicalyceal anatomy related to the accessibility of the lower pole calyces. The cut-off value for IPA and IW was 45.8°(p < 0.001) and 7.8 mm (p < 0.001), respectively. CONCLUSIONS: IPA < 45.8° and IW <7.8 mm were negative predictors to access the lower pole calyces when using reusable fURS during RIRS.

Thermography-Based Comparison of Irrigation Temperatures Between Moses Mode and Virtual Basket Mode: An In Vitro Phantom Study.

Objectives: This study aims to evaluate changes in irrigation fluid temperatures during laser activation by using thermography, with comparison between Moses mode (MM) and virtual basket mode (VBM). Materials and Methods: Experiments were performed using an unroofed pyelocaliceal model. The laser was fired for 60 seconds at 0.4 J/60 Hz. Three runs were tested per setting using short pulse mode, long pulse mode, MM contact, and VBM. The time to reach threshold of thermal injury (43°C) was evaluated using thermometer and thermography, both with and without saline irrigation (25 mL/min). These outcomes were compared between laser pulse modes. Results: In measurement of time to reach the threshold, thermography-based time was significantly shorter than thermometer-based time in all laser modes under the condition of no irrigation. Thermography measurement results indicate that the speed of temperature rise depends on laser pulse modes, and the time to reach the threshold in MM was significantly shorter than that in VBM (9.0 seconds vs 14.3 seconds, p = 0.03). When 25 mL/min saline irrigation was used, the peak temperatures by both thermometer and thermography measurements did not exceed the threshold during laser activation. Conclusions: Thermography-based evaluation suggests that irrigation temperatures near mucosa around stones can rapidly elevate during laser lithotripsy when the irrigation condition is poor. Temperature rise speed in MM may be more rapid than that in VBM. To prevent thermal injury, laser pulse modes must be used selectively according to the condition of irrigation.

Indications, preferences, global practice patterns and outcomes in retrograde intrarenal surgery (RIRS) for renal stones in adults: results from a multicenter database of 6669 patients of the global FLEXible ureteroscopy Outcomes Registry (FLEXOR).

PURPOSE: To collect a multicentric database on behalf of TOWER research group to assess practice patterns and outcomes of retrograde intrarenal surgery (RIRS) for kidney stones. METHODS: Inclusion criteria: age ≥ 18 years, normal renal/calyceal system anatomy, calculi of any size, number, and position. STUDY PERIOD: January 2018 and August 2021. Stone-free status: absence of fragments > 2 mm, assessed post procedure according to the local protocol (KUB X-Ray and/or ultrasound or non-contrast CT scan). RESULTS: Twenty centers from fifteen countries enrolled 6669 patients. There were 4407 (66.2%) men. Mean age was 49.3 ± 15.59 years. Pain was the most frequent symptom indication for intervention (62.6%). 679 (10.2%) patients underwent RIRS for an incidental finding of stones. 2732 (41.0%) patients had multiple stones. Mean stone size was 10.04 ± 6.84 mm. A reusable flexible ureteroscope was used in 4803 (72.0%) procedures. A sheath-less RIRS was performed in 454 (6.8%) cases. Holmium:YAG laser was used in 4878 (73.1%) cases. A combination of dusting and fragmentation was the most common lithotripsy mode performed (64.3%). Mean operation time was 62.40 ± 17.76 min. 119 (1.8%) patients had an intraoperative injury of the ureter due to UAS insertion. Mean postoperative stay was 3.62 ± 3.47 days. At least one postoperative complication occurred in 535 (8.0%) patients. Sepsis requiring intensive care admission occurred in 84 (1.3%) patients. Residual fragments were detected in 1445 (21.7%) patients. Among the latter, 744 (51.5%) patients required a further intervention. CONCLUSION: Our database contributes real-world data to support to a better understanding of modern RIRS practice and outcomes.

Comparison of stone retropulsion between Moses mode and virtual basket mode: an in vitro study using artificial stones.

This study aimed to evaluate stone retropulsion in various laser pulse modes in both Moses mode (MM) and virtual basket mode (VBM). Experiments were performed using a channel-shaped rubber rail and artificial stones. We compared short pulse mode and long pulse mode in both MM and VBM with the laser tip positioned so that it was touching and at 1 and 2 mm distances from the stone surface. Stone retropulsion was measured after the laser fired for 10 s in three different laser settings: 0.5 J/8 Hz, 0.8 J/8 Hz and 1.0 J/8 Hz. When the laser tip was touching the artificial stone, stone retropulsion in MM was significantly shorter than that in VBM in all laser settings (P < 0.01, P = 0.02 and P = 0.02, respectively). At 1-mm distance, stone retropulsion in MM was significantly shorter than that in VBM in 0.8 J/8 Hz and 1.0 J/8 Hz settings (P < 0.01 and P = 0.01, respectively). At 2-mm distance, however, there were no differences between MM and VBM in stone retropulsion in any laser settings. Stone retropulsion was not significantly different between the laser settings at 1-mm distance in MM, or when touching in VBM. In conclusion, stone retropulsion distance in MM can be shorter than that in VBM. Stone retropulsion in MM and VBM may be differently influenced by laser settings and laser tip position.

Primary impact of simultaneous use of double devices through one-working channel when performing flexible ureteroscope with ureteral access sheath for single ureteral stone: In bench and retrospective clinical study.

OBJECTIVES: This study aimed to compare the simultaneous use of two devices versus a single device through a single working channel in flexible ureteroscopy using a ureteral access sheath for single ureteral stones. METHODS: In a bench study, the time to (i) set laser fiber, (ii) exchange laser fiber and nitinol basket through working channel, and (iii) pull out the device from working channel were measured 10 times in each step. In a clinical study, 156 patients who underwent flexible ureteroscopy with a ureteral access sheath for a ureteral stone in middle and upper ureter between April 2019 and November 2021 were assessed. One device was used at a time for 79 patients (S-Group) and two were simultaneously used for 77 (D-Group). Surgical outcomes and complications were compared. RESULTS: In the bench study, the mean time to change from laser fiber to basket and from basket to laser fiber through the working channel were 26.1 ± 3.7 s and 23.6 ± 2.0 s (p = 0.084), respectively, which were significantly longer than the laser setup time (p < 0.001). In the clinical study, although the stone-free rate was not significantly different between the groups (S-Group 89.8%, D-Group 93.5%; p = 0.412), the median operation time was significantly shorter (p < 0.001) and the rate of postoperative stenting was significantly lower (p = 0.002) in the D-Group. There were no significant between-group differences in intra- and post-operative complications. CONCLUSION: The simultaneous use of two devices through a single working channel is safe and could help save the time needed to exchange the laser fiber and nitinol basket.