Retrograde Intrarenal Surgery Research Articles

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

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

The relationship between stone-free and patient position in retrograde intrarenal surgery: a randomized prospective study

PurposeResidual fragments not removed with urinary stone surgery may become symptomatic. In this context, this study was carried out to investigate the effect of performing retrograde intrarenal surgery, which is conventionally performed in the lithotomy position, in the modified lithotomy position (Trend-side) on stone-free rates following the surgery.MethodsThis prospective study consisted of 100 patients with a single kidney stone smaller than 2 cm between 2021 and 2023. These patients were randomized into two groups of 50 patients each to be operated on in the conventional lithotomy and Trend-side positions. Variables were compared using independent t test for continuous variables and chi-square test for categorical variables.ResultsThere was no significant difference between the lithotomy and Trend-side position groups in terms of preoperative size, density, location of the stone, and hydronephrosis degree. Stone-free rate was 72% (n = 36) in the lithotomy group and 92% (n = 46) in the Trend-side group. Hence, there was a significant difference between the groups in the stone-free rate in favor of the Trend-side group (p = 0.009). Fragmentation time was statistically significantly shorter in the Trend-side group than in the lithotomy group (34 ± 17 min vs. 43 ± 14 min; p = 0.006). There was no significant difference between the groups in postoperative complication rates.ConclusionPerforming retrograde intrarenal surgery in the Trend-side position shortened the duration of fragmentation compared to the lithotomy position and was associated with higher stone-free rates. In conclusion, the Trend-side position can be safely preferred in patients undergoing retrograde intrarenal surgery due to kidney stones.

Urinary Tract Infection Predictors in Patients Undergoing Retrograde IntraRenal Surgery for Renal Stones: Does the Instrument Make the Difference?

Background: Retrograde intrarenal surgery (RIRS) using flexible ureterorenoscopes is a cornerstone approach for renal stone removal, yet it carries a significant risk of postoperative urinary tract infection (UTI). With the emergence of single-use ureterorenoscopes, there is growing interest in their potential to mitigate this risk. This study aimed to compare the postoperative infection rates between single-use and multi-use ureterorenoscopes in RIRS procedures and to identify predictors of postoperative UTI. Methods: Data were collected from 112 consecutive patients who underwent RIRS for renal stones between March 2022 and September 2023. Peri-operative variables including age, gender, body mass index (BMI), stone size, stone location, type of ureterorenoscope, Hounsfield Units (HU), pre-operative hydronephrosis, laboratory analysis, and operative time were evaluated. Univariate and multivariate logistic regression analyses were performed to assess the predictors of postoperative UTI. Results: Of the cohort, 77 surgeries (68.7%) utilized multi-use ureterorenoscopes, while 35 (31.3%) utilized single-use devices. Stone diameter, number of stones, type of ureterorenoscope, and operative time were significant predictors of postoperative UTI in the univariate analysis. Multivariable logistic regression showed that operative time (OR, 1.3; 95% CI, 0.55–0.99; p = 0.03) and type of ureterorenoscope (multi-use vs. single-use) (OR, 1.14; 95% CI, 1.08–1.2; p < 0.001) were independent predictors of postoperative UTI. Conclusions: In conclusion, this study highlights that multi-use ureterorenoscopes and prolonged operative time are associated with an increased risk of postoperative UTI in RIRS procedures. Careful pre-operative evaluation and meticulous patient selection are essential to minimize the occurrence of postoperative UTIs and optimize patient outcomes in RIRS for renal stones.

The Effect of Reusable Flexible Ureteroscope Aging on the Efficacy and Safety of Retrograde Intrarenal Surgery.

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 X2) 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.

Clinical efficacy analysis of tip‑flexible suctioning ureteral access sheath combined with disposable flexible ureteroscope to treat 2-4cm renal stones.

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 (2-4cm in diameter). 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. 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). Compared to T-UAS, combining TFS-UAS with DFU for treating renal stones of 2-4cm diameter, although more time-consuming, resulted in higher SFRs and improved safety.

Does prior PCNL affect RIRS? A retrospective analysis of a single center data.

The aim of this study is to investigate the results and safety of retrograde intrarenal surgery (RIRS) in patients who have previously undergone percutaneous nephrolithotomy (PCNL). A retrospective analysis included patients who underwent RIRS for kidney stones between August 2018 and April 2023. Group 1 comprised 396 patients who underwent primary RIRS, while Group 2 included 231 individuals who had RIRS after previous PCNL. Evaluation parameters included preoperative characteristics, stone attributes, operative details, treatment outcomes, stone-free status, and complications. Statistical analysis utilized Student's t test, Mann-Whitney U test, and Pearson Chi-square test (p < 0.05). The mean age, body mass index, stone number, mean stone burden, and SFS were not statistically different between the groups. Lower pole stones were identified in 144 patients in Group 1 and 88 patients in Group 2 (p = 0.315). In Group 1 and Group 2, the mean operation time and fluoroscopy time were 65.23 ± 18.1min, 81.32 ± 14.3min, 26.34 ± 8.31s, 46.61 ± 7.6s, respectively, showing statistically significant differences between the groups (p = 0.013, p < 0.001, respectively). Infundibulum stenosis was identified and treated with a laser in 12% of Group 2 cases. Complications occurred in 12 patients in Group 1 and 14 patients in Group 2 (p = 0.136). A history of PCNL may contribute to extended operation times and increased fluoroscopy exposure in subsequent RIRS without significantly affecting postoperative SFS or complication rates.

External validation of a nomogram for outcome prediction in management of medium-sized (1-2 cm) kidney stones.

Stone nomogram by Micali et al., able topredict treatment failure of shock-wave lithotripsy (SWL), retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PNL) in the management of single 1-2 cm renal stones, was developed on 2605 patients and showed a high predictive accuracy, with an area under ROC curve of 0.793 at internal validation. The aim of the present study is to externally validate the model to assess whether it displayed a satisfactory predictive performance if applied to different populations. External validation was retrospectively performed on 3025 patients who underwent an active stone treatment from December 2010 to June 2021 in 26 centers from four countries (Italy, USA, Spain, Argentina). Collected variables included: age, gender, previous renal surgery, preoperative urine culture, hydronephrosis, stone side, site, density, skin-to-stone distance. Treatment failure was the defined outcome (residual fragments >4 mm at three months CT-scan). Model discrimination in external validation datasets showed an area under ROC curve of 0.66 (95% 0.59-0.68) with adequate calibration. The retrospective fashion of the study and the lack of generalizability of the tool towards populations from Asia, Africa or Oceania represent limitations of the current analysis. According to the current findings, Micali's nomogram can be used for treatment prediction after SWL, RIRS and PNL; however, a lower discrimination performance than the one at internal validation should be acknowledged, reflecting geographical, temporal and domain limitation of external validation studies. Further prospective evaluation is required to refine and improve the nomogram findings and to validate its clinical value.

New infundibulopelvic angle measurement method can predict stone-free rates following retrograde intrarenal surgery.

To enhance the accuracy of predicting stone-free rates after retrograde intrarenal surgery, we devised a novel approach to assess the renal infundibulopelvic angle. We conducted a retrospective review of patient records for those who underwent retrograde intrarenal surgery for renal stones between April 2018 and August 2019. Patient demographics, stone characteristics, and perioperative data were recorded. Subsequently, we introduced a modified angle measurement called the pelvic stone angle and evaluated its predictive performance for stone-free rates by comparing it with the traditional method in scoring systems. A total of 43 individuals were included in this study. Notable differences in stone burden and Hounsfield unit measurements were found between stone-free and non-stone-free patients. The pelvic stone angle demonstrated a good model fit when used in scoring systems, performing equally well as the conventional approach. The area under the receiver operating characteristic curve for the R.I.R.S. scoring system using the pelvic stone angle and the conventional approach did not show a significant difference. In conclusion, the predictive ability of the pelvic stone angle for stone-free rates was comparable to the old measurement method. Moreover, scoring systems using the pelvic stone angle exhibited a better model fit than those using the conventional approach.

Prospective Evaluation of Risk Factors Responsible for Infection Following Retrograde Intrarenal Surgery

Prospective Evaluation of Risk Factors Responsible for Infection Following Retrograde Intrarenal Surgery

International Alliance of Urolithiasis (IAU) guideline on retrograde intrarenal surgery (Russian adaptation)

Introduction. The emergence of new scientific and clinical evidence on the use of retrograde intrarenal surgery (RIRS) for the management of kidney stones has prompted periodic systematisation, analysis, and evaluation of outcomes to standardise its application and determine future directions for research and development.Objective. To present the Russian adaptation of a guideline on retrograde intrarenal surgery from the International Urolithiasis Alliance guideline series to provide a theoretical basis for urologists performing RIRS.Materials &amp; Methods. A systematic review was conducted on the RIRS-associated publications available in the PubMed database to prepare a set of recommendations during the period from 1 January 1964 until 1 October 2021. The recommendations were evaluated using the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) system, which classifies, evaluates, develops, and examines recommendations. The modified Oxford Centre for Evidence-Based Medicine's (OCEBM) system for categorising the level of evidence and relevant comments have been applied to assess the strength of the conclusions.Results. The research team conducted a comprehensive analysis of 36 published clinical guidelines on the following topics: 1. Indications and Contraindications 2. Preoperative Imaging 3. Preoperative Ureteral Stenting 4. Preoperative Medications 5. Perioperative Use of Antibiotics 6. Use of Antithrombotic Therapy 7. Anesthesia Issues 8. Intraoperative Positioning 9. Equipment 10. Complications.Conclusion. A series of recommendations for RIRS, offered here should help provide safe and effective performance of RIRS.

Cumulative sum analysis of the learning curve for retrograde intrarenal stone surgery in newbie surgeons.

This study investigated the learning curve of retrograde intrarenal surgery (RIRS) in patients with medium-sized stones using cumulative sum analysis (CUSUM) to evaluate the competence and proficiency of three new surgeons during their first RIRS procedures. We conducted a retrospective review of 227 patients from 2019 to 2022 at a single institution. The patients were divided into four groups based on the operating surgeon: tutor surgeon (85 patients), newbie surgeon A (21 patients), newbie surgeon B (85 patients), and newbie surgeon C (36 patients). Patients had one or multiple stones with the largest stone diameter fell within the range of 10-30mm. Fragmentation efficacy was calculated as "removed stone volume (mm3) divided by operative time (minutes)." CUSUM analysis monitored changes in fragmentation efficacy and validated surgical outcomes. No statistically significant differences were observed in the total stone volume, maximum stone size, or total operation time between the three newbie surgeons and the tutor surgeon. The mean fragmentation efficacy value was comparable among the newbie surgeons, but significantly different from that of the tutor surgeon. The minimum acceptable fragmentation efficacy level was set at 25.12mL/min, based on the tutor's average value. The CUSUM curves for the three surgeons initially remained relatively flat until Cases 12-15, after which they increased and eventually plateaued. Stone-free rates and postoperative complications did not differ significantly among the surgeons. Learning curve analysis for the three newbie surgeons indicated that approximately 12-15 cases were required to reach a plateau.

Retrograde Intrarenal Surgery for Lithiasis Using Suctioning Devices: A Shift in Paradigm?

New suction endoscopes, ureteral access sheaths (UAS) and catheters aim to improve the efficacy of flexible ureteroscopy and optimize its safety. Suction UAS with non-flexible tips have shown promising results, especially in maintaining low intrarenal pressure, but also in removing small debris and reducing the "snow globe" effect. In addition, suctioning UAS with a flexible tip offers the advantage of being able to be navigated through the pyelocaliceal system to where the laser lithotripsy is performed. It can also remove small stone fragments when the flexible ureteroscope is retracted, using the Venturi effect. Direct in-scope suction (DISS) involves aspirating dust and small stone debris through the working channel of a flexible ureteroscope, thus regulating intrarenal pressure and improving visibility. Steerable aspiration catheters are other devices designed to increase stone clearance of the pyelocaliceal system. They are inserted under fluoroscopic guidance into every calyx after retraction of the flexible ureteroscope, alternating irrigation and aspiration to remove dust and small gravels. Combining flexible-tip suction UAS and the DISS technique may offer some advantages worth evaluating. The advantage of using these instruments to achieve a low intrarenal pressure was demonstrated. The true practical impact on the long-term stone-free status is a matter requiring further studies.

Evaluation of the effect of 9.5/11.5-fr ureteral access sheath use on acute kidney injury with the myo-inositol oxygenase biomarker in patients undergoing retrograde intrarenal surgery: a prospective, randomized, and controlled study

Introduction We aimed to investigate whether a low intrarenal pressure provided by ureteral access sheath (UAS) use had a positive effect on the prevention of acute kidney injury through the evaluation of the myo-inositol oxygenase (MIOX). Material and methods The patients were divided into two groups according to whether a 9.5/11.5-Fr UAS was used during retrograde intrarenal surgery (RIRS): UAS group and non-UAS group. RIRS was performed under gravity irrigation and manual pumping was not used. For the measurement of MIOX, 5 cc blood samples were taken from the patients preoperatively and four hours postoperatively. Results Operation time and hospital stay were significantly longer in the UAS group. The mean preoperative and postoperative MIOX values were 0.77 ± 0.36 ng/ml and 0.74 ± 0.38 ng/ml, respectively, in the UAS group, and 0.74 ± 0.31 ng/ml and 0.83 ± 0.40 ng/ml, respectively, in the non-UAS group. The mean MIOX change was −0.29 ± 0.36 in the UAS group and 0.08 ± 0.44 in the non-UAS group, indicating no significant difference between the groups. Conclusion Even if UAS is not used, significant acute kidney injury is not observed under gravity irrigation and therefore, if we avoid manual pumping, the intrarenal pressure remains low, thus potentially rendering the use of 9,5/11,5-Fr UAS unnecessary.

Robot-assisted retrograde intrarenal surgery: first clinical experience with the ILY® system.

 

Efficacy of Flexible Ureteroscopy Lithotripsy and Percutaneous Nephrolithotomy in the Treatment of Patients with Kidney Stones and Their Impact on Inflammatory Response and Renal Function.

Kidney stones are one of the most common benign diseases in urology. As technology updates and iterates, more minimally invasive and laparoscopic surgeries with higher safety performance appear. This paper explores the effectiveness of retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PCNL) in treating kidney stones, focusing on their effects on inflammatory responses and renal function. We conducted a retrospective analysis of 200 patients with kidney stones treated in our hospital between June 2019 and June 2023. 100 patients who underwent RIRS were included in the RIRS group. Another 100 patients who underwent PCNL treatment were included in the PCNL group. The intraoperative blood loss, operation duration, and hospitalization time of the two groups of patients were recorded and compared. The enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of inflammatory factors in the serum of the two groups of patients: [serum amyloid A (SAA), interleukin-6 (IL-6) and high-sensitivity C-reactive protein (CRP)] and renal function index [blood urea nitrogen (BUN), creatinine (Scr) and serum cystatin (Cys-c)]. The two groups of patients were recorded separately: Postoperative complications and stone-free rate. Operation duration was longer for the RIRS group than the PCNL group, which exhibited significantly less intraoperative blood loss and shorter hospital stays (p < 0.05). Before surgery, there was no statistically significant difference in the serum levels of SAA, IL-6, and CRP between the two groups of patients (p > 0.05). On the first day after surgery, the serum SAA levels in both groups were lower than before surgery, IL-6 and CRP levels were higher than before surgery, and the serum levels of SAA, IL-6, and CRP in the RIRS group were significantly lower than those in the PCNL group. The difference was statistically significant (p < 0.05). Before surgery, there was no statistically significant difference in the serum BUN, Scr, and Cys-c levels between the two groups of patients (p > 0.05). On the first day after surgery, the serum BUN, Scr, and Cys-c levels of the two groups of patients were significantly higher than those before surgery. The serum BUN, Scr, and Cys-c levels of the RIRS group were significantly lower than those of the PCNL group, and the difference was statistically significant (p < 0.05). Both surgical methods have sound stone-clearing effects regarding long-term stone clearance rates 1 month and 3 months after surgery (p > 0.05). PCNL had a better stone clearance rate on the 2nd postoperative day (p < 0.05). The incidence of postoperative complications in the RIRS group was significantly lower than that in the PCNL group, and the difference was statistically significant (p < 0.05). For kidney stones ≤2 cm, PCNL showed higher stone clearance rates on the second postoperative day. However, RIRS and PCNL demonstrated adequate long-term stone clearance at 1 and 3 months post-surgery. Both surgical methods are safe and effective, and RIRS is safer than PCNL. Compared with PCNL, RIRS is a new method of kidney stone operation, which has less trauma to the patient's body and fewer complications after the operation, speeding up the recovery process of the patient.

COVID-19 outbreak impact on urolithiasis treatments: A multicenter retrospective study across 9 urological centers

Abstract Background The coronavirus disease (COVID-19) pandemic has posed challenges to the global health care community, affecting the management of upper urinary tract stones. Materials and methods This retrospective study involved 9 Italian centers. We compared the 12-month period prior to COVID-19 (March 1, 2019, to February 28, 2020; Period A) with the COVID-19 period (March 1, 2020, to February 28, 2021, Period B). This study aimed to compare outcomes during Periods A and B, specifically focusing on the overall number of treatments, rate of urgent/elective cases, and operational complexity. Results A total of 4018 procedures were collected, comprising 2176 procedures during Period A and 1842 during Period B, indicating a loss of 15.35% (p &lt; 0.001). In the elective cases, 1622 procedures were conducted in Period A, compared with 1280 in Period B, representing a 21.09% reduction in cases (p = 0.001). All types of stone treatments were affected: extracorporeal shock wave lithotripsy (−29.37%, p = 0.001), percutaneous nephrolithotomy (−26.47%, p = 0.008), retrograde surgeries for renal stones (−10.63%, p = 0.008), and semirigid ureterolithotripsy (−24.86%, p = 0.008). Waiting lists experienced significant delays during Period B. The waiting time for elective procedures increased during Period B (p &lt; 0.001). For ureteral stones, the mean waiting time in Period A was 61.44 days compared with 86.56 days in Period B (p = 0.008). The waiting time for renal stones increased from 64.96 days in Period A to 85.66 days in Period B for retrograde intrarenal surgery (p = 0.008) and from 96.9 days to 1103.9 days (p = 0.035) for percutaneous nephrolithotomy procedures. Conclusions Our study demonstrates that COVID-19 significantly disrupted endourological services across the country. Our data underline how patients received treatment over a prolonged period, potentially increasing the risk of stone-related complications and patient discomfort.

A new protocol for renal collecting system sterilization with antibiotic irrigation during lithotripsy in retrograde intrarenal surgery: a prospective, comparative study

PurposeTo present a new protocol using antibiotic irrigation during lithotripsy in retrograde intrarenal surgery (RIRS) to provide sterility of the renal collecting system.MethodsThis prospective study included 102 patients who underwent RIRS between January 2022 and August 2023. The patients were examined in two groups as those who received antibiotic irrigation (n:51) and standard irrigation (n:51). In the antibiotic irrigation group, 80 mg of gentamicin was dissolved in normal saline in a 3 L irrigation pouch to obtain a 26.7 mg/L concentration. In the standard irrigation group, normal saline was used. Preoperative information, including age, sex, body mass index (BMI), ASA score, stone side, volume, and density, and the Seoul National University Renal Stone Complexity (S-ReSC) score. The groups were compared with respect to postoperative fever (> 38 °C), urinary tract infection (UTI), systemic inflammatory response syndrome (SIRS), infectious complications such as sepsis, and stone-free rate.ResultsNo statistically significant difference was determined between the groups with respect to age, sex, BMI, ASA score, stone side, volume and density, and S-ReSC score (p > 0.05 for all). Statistically significant differences were determined between the groups with respect to postoperative fever (p = 0.05), SIRS (p = 0.05), and hospital length of stay (p = 0.05). Sepsis was observed in one patient in the standard irrigation group and in none of the antibiotic irrigation group.ConclusionThe reliability, efficacy, and utility of antibiotic irrigation during lithotripsy in RIRS were presented in this study as a new protocol for sterilization of the renal collecting system which will be able to reduce infectious complications.

Introducing an lsoprenaline Eluting Guidewire: Report on its Design and the Results of the Dose-Determining Pilot Study.

Introduction: Retrograde intrarenal surgery (RIRS) is associated with complications, many of which are related to the intrarenal pressure (IRP). We aim to describe the design of a novel isoprenaline-eluting guidewire ("IsoWire") and present the results from the first in vitro release studies and the first animal studies showing its effect on IRP. Materials and Methods: The IsoWire comprises a Nitinol core surrounded by a stainless-steel wire wound into a tight coil. The grooves created by this coil provided a reservoir for adding a hydrogel coating into which isoprenaline, a beta-agonist, was loaded. Animal studies were performed using a porcine model. For the control, IRP, heart rate (HR), and mean arterial pressure (MAP) were measured continuously for 6 minutes with a standard guidewire in place. For the experiment, the standard hydrophilic guidewire was removed, the IsoWire was inserted into the renal pelvis, and the same parameters were measured. Results: In vitro analysis of the isoprenaline release profile showed that most (63.9 ± 5.9%) of the loaded drug mass was released in the 1st minute, and almost all of the drug was released in the first 4 minutes exponentially. Porcine studies showed a 25.1% reduction in IRP in the IsoWire that released 10 μg in the 1st minute; however, there was a marked increase in HR. The average percentage reduction in IRP was 8.95% and 21.3% in the IsoWire that released 5 and 7.5 μg of isoprenaline, respectively, with no changes in HR or MAP. Conclusions: The IsoWire, which releases 5 and 7.5 μg of isoprenaline in the 1st minute, appears to be safe and effective in reducing the IRP. Further studies are needed to establish whether the isoprenaline-induced ureteral relaxation will render easier insertion of a ureteral access sheath, reduce IRP during sheathless RIRS, or even promote the practice of sheathless RIRS.

7.5F Mini Flexible Ureteroscope in Retrograde Intrarenal Surgery: Initial Results from a Multicenter Randomized Clinical Trial.

Objective: To report the initial results of an randomized clinical trail comparing the safety and efficacy between 7.5F and 9.2F flexible ureteroscope (FUS) in the management of renal calculi <2 cm. Materials and Methods: Eighty patients were enrolled and received retrograde intrarenal surgery (RIRS) with a different size FUS. The operation results and complications were compared. Results: Two cases in the 7.5F group and four cases in the 9.2F group failed to insert the 12/14F ureteral access sheath (UAS), respectively, and no significant difference (p = 0.396) was noted. However, 10/12F UAS was inserted in the 7.5F group, but not available in the 9.2F group, and thus, the 10/12F UAS inserting rate in the 7.5F group was higher than in the 9.2F group (100% vs 0%, p = 0.014), and the UAS insertion failure rate in 9.2F group was higher than in the 7.5F group (10% vs 0%, p = 0.040). The operation time in 7.5F group was shorter than the 9.2F group (35.60 ± 7.86 vs 41.05 ± 8.14, p = 0.003). Less irrigation was required in 7.5F group (813.93 ± 279.47 mL vs 1504.18 ± 385.31 mL, p = 0.000). The postoperative fever rate in 9.2F group was higher than 7.5F group (20% vs 5%, p = 0.043). There was no significant difference in sepsis (0% vs 2.5%, p = 0.314) between the two groups. No significant difference was noted in hospital stay (0.93 ± 0.49 days vs 1.14 ± 0.64 days, p = 0.099) between the two groups. The final stone-free rate (SFR) in 7.5F group was higher than 9.2F group (95% vs 80%, p = 0.043). Conclusion: The latest 7.5F mini FUS was a reliable instrument in RIRS to keep a good visualization with low requirement of irrigation, low postoperative infection complication, and also a high SFR when compared with the conventional 9.2F FUS. Clinical Trial Registration: NCT05231577.

Stone centers: a national survey on surgical techniques performed in Italy.

Recurrent and complex stone disease may be considered a challenging disease. In 2018, the Calculus group of the SIU (Italian Society of Urology) set itself the goal of establishing the minimum requirements for a center that could continuously manage urolithiasis pathology, named a Stone Center. In this study we present the results of a pilot survey carried out in 2019 with the aim of drawing a map of the situation of Italian urological centers dealing with urinary stones. A total of 260 national urology departments dealing with urolithiasis surgery were contacted for this study. A survey was issued to each of the centers to determine the number of patients treated for urinary stones and the amount of procedures performed per year: 1) extracorporeal shock wave lithotripsy ESWL; 2) ureterorenoscopy URS; 3) retrograde intrarenal surgery RIRS; 4) percutaneous nephrolithotomy PCNL. Out of 260 centers contacted, 188 fulfilled the survey. Outcomes were quite variable, with approximately 37% of the centers lacking a lithotripter, and 46% of those that did have it performing fewer than 100 treatments per year. In terms of endoscopic procedures, more than 80% of the centers contacted performed URS or RIRS; however, when it came to percutaneous lithotripsy, these numbers dropped significantly; 33% of the centers contacted did not perform PCNL, and of those who did, 18% had less than 5 years of experience as a center. Our survey shows a very heterogeneous national picture about urolithiasis treatments. Our goal is to create national paradigms to be able to define stone centers where the patient suffering from complex urinary stones can find a network of professionals with an adequate armamentarium suitable for the management of their pathology.