European Association of Urology Section of Urolithiasis and International Alliance of Urolithiasis Joint Consensus on Retrograde Intrarenal Surgery for the Management of Renal Stones

Application of 11/13Fr suctioning ureteral access sheath and 8.55Fr single-use digital flexible ureteroscope in one-stage flexible ureteroscopic lithotripsy: an initial experience of 900 cases

OBJECTIVES

To report our initial experience of one-stage flexible ureteroscopic lithotripsy(FURL) with 11/13Fr suctioning ureteral access sheath(UAS) and 8.55Fr single-use digital flexible ureteroscope(SDFU) in upper ureteral or renal calculi.

MATERIALS AND METHODS

We retrospectively collected the clinical data of 900 adult patients with upper ureteral or renal calculi treated by FURL with 11/13Fr suctioning UAS and 8.55Fr SDFU from January 2022 to April 2024. Demographics, peri- and postoperative outcomes were assessed.

RESULTS

In all, 40 of 940 cases(4.26%) failed to introduce UAS and required second-stage FURL because of ureterostenosis and were excluded. Mean stones size of the remaining 900 eligible cases was 1.68 ± 0.58 cm in greatest diameter. There were 228 cases of upper ureteral stone, 456 cases of renal stone and 216 cases of concomitant ureteral and renal calculi. The mean operation time was 52.20 ± 20.21 min and the postoperative hospital stay was 2.87 ± 1.37 days. The stone-free rate of 1 month postoperatively was 89.56% and only 2.44% of patients with residue underwent additional reoperation. The rate of postoperative fever, postoperative pain needing analgesic and slight ureteral mucosal injury were 5.11%, 8.22% and 7.78%, respectively. None of patient suffered from severe complications, such as sepsis or ureteral perforation.

CONCLUSION

It's practical and suitable for the vast majority of adult patients to undergo FURL in single session with 11/13Fr suctioning UAS without preoperative stenting. FURL with 11/13Fr suctioning UAS and 8.55Fr SDFU is feasible, reliable, safe, and efficient in the management of renal stone and upper ureteral stone.

An international delphi survey and consensus meeting to define the risk factors for ureteral stricture after endoscopic treatment for urolithiasis

PURPOSE

Iatrogenic ureteral strictures (US) after endoscopic treatment for urolithiasis represent a significant healthcare concern. However, high-quality evidence on the risk factors associated with US is currently lacking. We aimed to develop a consensus statement addressing the definition, risk factors, and follow-up management of iatrogenic US after endoscopic treatment for urolithiasis.

METHODS

Utilizing a modified Delphi method, a steering committee developed survey statements based on a systematic literature review. Then, a two-round online survey was submitted to 25 experts, offering voting options to assess agreement levels. A consensus panel meeting was held for unresolved statements. The predetermined consensus threshold was set at 70%.

RESULTS

The steering committee formulated 73 statements. In the initial survey, consensus was reached on 56 (77%) statements. Following in-depth discussions and refinement of 17 (23%) statements in a consensus meeting, the second survey achieved consensus on 63 (86%) statements. This process underscored agreement on pivotal factors influencing US in endoscopic urolithiasis treatments.

CONCLUSIONS

This study provides a comprehensive list of categorized risk factors for US following endoscopic urolithiasis treatments. The objectives include enhancing uniformity in research, minimizing redundancy in outcome assessments, and effectively addressing risk factors associated with US. These findings are crucial for designing future clinical trials and guiding endoscopic surgeons in mitigating the risk of US.

Experience of Multiple Super-Selective Renal Angiographic Embolization (SRAE) After Minimally-Percutaneous Nephrolithotomy Haemorrhage: A Case Report

Minimally invasive percutaneous nephrolithotomy (mini-PCNL) maintains a stone clearance rate similar to standard PCNL while reducing blood loss. Bleeding is a complex and serious complication that can arise after PCNL surgery. Pseudoaneurysm (PA) is an uncommon type of delayed bleeding problem, which affects less than 1% of patients after PCNL. The most effective treatment for severe post-PCNL hemorrhage is super-selective renal angiographic embolization (SRAE), but it can fail in some patients and require additional surgical intervention. This report details the case of a male patient, 55 years old, who experienced severe bleeding four times and had three SRAE procedures and one laparoscopic procedure after PCNL. The presence of a renal artery pseudoaneurysm was not initially identified during the first two attempts of angiography due to arterial spasm and a small, undeveloped lesion. This case report is intended to enhance awareness of tiny pseudoaneurysms, emphasizing the importance of avoiding oversight to improve the success rate of embolization.

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.

Could radiological parameters help to predict the failure of ureteral access sheath placement

To identify the radiological parameters which may help to predict the success of ureteral access sheath (UAS) placement during retrograde intrarenal surgery (RIRS).The study included 49 patients in whom failure ureteral access sheath placement in RIRS and 49 control group patients who were successfully placement between January 2023 and December 2023. The age, gender, body mass index (BMI), non-contrast computed tomography (NCCT), and kidney ureter bladder (KUB) radiographs were compared between the two groups. Measurements of the anteroposterior (ap) diameter of the pelvic inlet, anteroposterior diameter of the pelvic outlet, interspinous distance diameter were taken from non-contrast computed tomography (NCCT), while pelvic anteroposterior diameter and pelvic lateral diameter were measured from kidney ureter bladder (KUB) radiography. There were no significant differences between the groups in age, gender, body mass index, ap pelvic inlet diameter, ap pelvic outlet, and interspinous distance diameter. However, a statistically significant difference was found between the pelvic ap diameter and pelvic lateral diameter values measured on the KUB radiography. The values for pelvic ap diameter and pelvic lateral diameter measured in the KUB radiographs can be used to predict the likelihood of UAS passage during RIRC procedures. However, further studies with larger patient groups are needed to establish a cut-off value.

Monitoring Intrarenal temperature changes during Ho: YAG laser lithotripsy in patients undergoing retrograde intrarenal surgery: a novel pilot study

Ho: YAG laser lithotripsy is widely used for urinary stone treatment, but concerns persist regarding its thermal effects on renal tissues. This study aimed to monitor intrarenal temperature changes during kidney stone treatment using retrograde intrarenal surgery with Ho: YAG laser. Fifteen patients were enrolled. Various laser power settings (0.8 J/10 Hz, 1.2 J/12 Hz) and irrigation modes (10 cc/min, 15 cc/min, 20 cc/min, gravity irrigation, and manual pump irrigation) were used. A sterile thermal probe was attached to a flexible ureterorenoscope and delivered into the calyceal system via the ureteral access sheath. Temperature changes were recorded with a T-type thermal probe with ± 0.1 °C accuracy. Laser power significantly influenced mean temperature, with a 4.981 °C difference between 14 W and 8 W laser power (p < 0.001). The mean temperature was 2.075 °C higher with gravity irrigation and 2.828 °C lower with manual pump irrigation (p = 0.038 and p = 0.005, respectively). Body mass index, laser power, irrigation model, and operator duty cycle explained 49.5% of mean temperature variability (Adj. R2 = 0.495). Laser power and operator duty cycle positively impacted mean temperature, while body mass index and specific irrigation models affected it negatively. Laser power and irrigation rate are critical for intrarenal temperature during Ho: YAG laser lithotripsy. Optimal settings and irrigation strategies are vital for minimizing thermal injury risk. This study underscores the need for ongoing research to understand and mitigate thermal effects during laser lithotripsy.

Arterial pseudoaneurysm: a rare complication following laser lithotripsy-case series and literature review

OBJECTIVE

To perform a comprehensive narrative review that will examine the risk factors and treatment outcomes of arterial pseudoaneurysm following laser flexible ureteroscopy (F-URS).

METHODS

A retrospective case series and a review of literature was performed. Clinical records from three patients treated for postoperative arterial pseudoaneurysm from January of 2021 to November 2023 were identified. A comprehensive literature review was also performed. The MEDLINE and Scopus databases were searched. The analysis was made by a narrative synthesis.

RESULTS

Three cases of postoperative arterial pseudoaneurysm were included, one from our center, one from Dubai, UAE, and one from Barcelona. The literature review identified six case reports, two after endocorporeal laser lithotripsy with thulium fiber laser (TFL) and four with Ho:YAG laser. All cases, from our series and literature review, presented with macroscopic hematuria and used high-power laser settings. All cases were treated by selective embolization.

CONCLUSION

Ho:YAG or TFL lasers are both capable of causing arterial pseudoaneurysms following F-URS if high-power settings are used. Selective artery embolization continues to be the treatment of choice with good outcomes.

Percutaneous nephrolithotomy or flexible ureteral lithotripsy, which one is better for patients with upper ureteral calculi of 1.5-2.0 cm in diameter

PURPOSE

First research to evaluate the clinical efficacy and safety of flexible ureteral lithotripsy (FURSL) and percutaneous nephrolithotomy (PCNL) in the treatment of the upper ureteral stone is between 1.5 cm and 2.0 cm in diameter since there is no consensus with such ureteral stone yet.

METHODS

From December 2018 to October 2022, 104 patients with calculi in the upper ureter received percutaneous nephrolithotomy (PCNL)or flexible ureteroscopic lithotripsy (FURSL) in our institution. The clinical data of the patients in the two groups were retrospectively searched. Stone removal rate, operation time, blood loss, postoperative pain score, postoperative inflammatory factor, postoperative complication rates and ureteral obstruction three months after the operation were compared between the two groups.

RESULTS

A total of 104 patients were included in the study. The stone clearance rate and the secondary surgery rate were 88.89% and 7.41% in the FURSL group, the figures were 97.96% and 2.0% in the PCNL group (p = 0.067, 0.497). Regarding ureteral obstruction three months after the operation, there were 2 patients in FURSL group and 0 patients in PCNL group(p = 0.497).Compared to patients in FURSL group, patients in the PCNL group had shorter operation time(PCNL 71.81 ± 18.94 min vs. FURSL 86.80 ± 22.49 min, p = 0.0004), fewer complications(PCNL 20.37% vs. FURSL 6.12%), and lower postoperative inflammatory factor(p = 0.0004), yet they got more hemoglobin drop (PCNL 13.14 ± 9.81 g/L vs. FURSL 4.77 ± 3.55 g/L, p < 0.0001), higher postoperative pain scores(p = 0.0017) in the first three postoperative days and longer hospital stay (PCNL 4.96 ± 1.21 days vs. FURSL 3.60 ± 0.83 days).

CONCLUSION

Both FURSL and PCNL were effective methods for treating upper ureteral stones of 1.5-2.0 cm in diameter given the extremely high stone clearance rate and a very low secondary surgery rate, as long as rare ureteral obstruction in medium-long term observation. Additionally, FURSL can effectively reduce surgical bleeding, postoperative pain, and hospital stay, while PCNL can decrease operation time, the risk of infection, and complications. Therefore, doctors could select suitable surgical treatment for those patients depending on their different clinical situations based on these findings.

Prevention of complications in endourological management of stones: What are the basic measures needed before, during, and after interventions?

Objective

This narrative review aims to describe measures to minimise the risk of complications during percutaneous nephrolithotomy (PCNL), ureteroscopy, and retrograde intrarenal surgery.

Methods

A literature search was conducted from the PubMed/PMC database for papers published within the last 10 years (January 2012 to December 2022). Search terms included "ureteroscopy", "retrograde intrarenal surgery", "PCNL", "percutaneous nephrolithotomy", "complications", "sepsis", "infection", "bleed", "haemorrhage", and "hemorrhage". Key papers were identified and included meta-analyses, systematic reviews, guidelines, and primary research. The references of these papers were searched to identify any further relevant papers not included above.

Results

The evidence is assimilated with the opinions of the authors to provide recommendations. Best practice pathways for patient care in the pre-operative, intra-operative, and post-operative periods are described, including the identification and management of residual stones. Key complications (sepsis and stent issues) that are relevant for any endourological procedure are then be discussed. Operation-specific considerations are then explored. Key measures for PCNL include optimising access to minimise the chance of bleeding or visceral injury. The role of endoscopic combined intrarenal surgery in this regard is discussed. Key measures for ureteroscopy and retrograde intrarenal surgery include planning and technique to minimise the risk of ureteric injury. The role of anaesthetic assessment is discussed. The importance of specific comorbidities on each step of the pathway is highlighted as examples.

Conclusion

This review demonstrates that the principles of meticulous planning, interdisciplinary teamworking, and good operative technique can minimise the risk of complications in endourology.

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.

Comparison of novel flexible and traditional ureteral access sheath in retrograde intrarenal surgery

OBJECTIVES

To compare the efficiency and safety of a novel flexible ureteral access sheath (f-UAS) and traditional ureteral access sheath (UAS) during retrograde intrarenal surgery (RIRS).

PATIENTS AND METHODS

Between January 2022 and September 2022, a total of 152 consecutive cases with renal stones underwent RIRS with the f-UAS. Their outcomes were compared with those of another 152 consecutive cases undergoing RIRS with traditional UAS using a 1:1 scenario matched-pair analysis, with matching parameters including age and stone size. The f-UAS is a novel UAS with a 10-cm-long tube at the tip that can follow the bends of flexible ureteroscope (f-URS).

RESULTS

Baseline characteristics were found to be similar between the two groups. The f-UAS group demonstrated significantly higher SFR (76.3% vs. 7.2%; P < 0.001) at 1 day postoperatively and a higher clearance rate of stone volume (98.11% vs. 91.78%; P < 0.001). The f-UAS group also had lower total complications rate (9.9% vs. 22.4%; P = 0.003), lower incidence of fever (5.9% vs 11.9%; P = 0.001), shorter operative times (56.5 min vs. 59.9 min; P = 0.047), and lower usage rate of baskets (17.1% vs. 100%; P < 0.001). There was no significant difference in SFR at 1 month postoperatively (P = 0.627) and in the length of postoperative hospital stay between the two groups (P = 0.225).

CONCLUSION

Compared to the traditional UAS during RIRS, the f-UAS showed several advantages, including higher SFR at 1 day postoperatively, shorter operative times, lower incidence of complications, and less use of basket.

Comparison of traditional and novel tip-flexible suctioning ureteral access sheath combined with flexible ureteroscope to treat unilateral renal calculi

OBJECTIVES

To compare the safety and efficacy of novel tip-flexible suctioning ureteral access sheath (NTFS-UAS) and traditional ureteral access sheath (T-UAS) combined with flexible ureteroscope for treating unilateral renal calculi.

MATERIALS AND METHODS

The clinical data of 214 patients with unilateral renal calculi treated by NTFS-UAS (n = 102) and T-UAS (n = 112) combined with flexible ureteroscope from August 2021 to April 2022 were analyzed retrospectively. Demographic characteristics, stone-related parameters, operative time, stone-free rates (SFR), hospitalization time and complication rate (CR) were analyzed.

RESULT

No significant difference was observed between the two groups in terms of demographic characteristics, stone-related parameters, intraoperative CR, and hospitalization time. The operative time of NTFS-UAS group was significantly shorter than T-UAS group (55.25 ± 11.42 min vs. 59.36 ± 15.59 min; P = 0.028). The NTFS-UAS group obtained significantly higher SFR on 1 day postoperatively (86.3% vs. 75.0%; P = 0.038), and higher SFR on 30 days postoperatively than T-UAS group (91.2% vs. 81.3%; P = 0.037). The hemoglobin loss of NTFS-UAS group (- 0.54 ± 0.69 g/dl) was significantly lower than T-UAS group (- 0.83 ± 0.66 g/dl; P = 0.002). There was a significantly lower incidence of overall CR (11.8% vs. 22.3%; P = 0.041), and infectious CR (8.8% vs. 18.8%; P = 0.037) in the NTFS-UAS group.

CONCLUSION

Compared to T-UAS combined with flexible ureteroscope for treating unilateral renal calculi, NTFS-UAS had superiority in higher SFR on 1 day and 30 days postoperatively. Shorter operation time, lower hemoglobin loss, lower incidences of overall and infectious CR were observed in NTFS-UAS group.

REGISTRATION NUMBER AND DATE

ChiCTR2300070210; April 5, 2023.

Influence of stone load on the outcome of same-session flexible ureteroscopy for bilateral upper urinary tract stones: a multicenter retrospective study

Purpose

This study aimed to evaluate the efficacy and safety of same-session flexible ureteroscopy (fURS) for the treatment of bilateral upper urinary tract stones and to examine the influence of stone load on the outcome of same-session fURS, stratifying by total diameter of stones (TDS) ≤30 mm vs. >30 mm.

Patients and methods

We retrospectively reviewed all cases of same-session fURS performed for bilateral upper urinary tract stones at four institutions between January 2017 and September 2020. All patients were divided into two groups based on TDS, ≤30 mm and >30 mm. Data on patient demographics, stone characteristics, surgical results, and complications were collected and analyzed for differences between the two groups. Stone-free rate (SFR) was defined as patients endoscopically stone-free or with radiological fragments <2 mm of each renal unit.

Results

A total of 121 patients with bilateral upper urinary tract stones underwent same-session fURS, consisting of 73 patients in the TDS ≤ 30 mm group and 48 patients in the TDS > 30 mm group. The mean bilateral stone size was 28.2 ± 12.2 mm (range: 9.1-38.4 mm), with a mean operating time of 97.1 ± 39.6 min (range: 19-220 min). The SFR was 54.5% after the first fURS, and SFR increased to 97.5% after re-fURS for residual stones. The operation time for the TDS > 30 mm group was longer than that of the TDS ≤ 30 mm group (85.1 ± 36.5 vs. 115.4 ± 37.4 min, p < 0.001). The SFR after the first fURS was significantly lower in the TDS > 30 mm group than in the TDS ≤ 30 mm group (25.0% vs. 73.9%, p < 0.001). Although there was no statistically significant difference in overall SFR between the two groups (93.7% vs. 100%, p = 0.060), the rate of re-fURS for residual stones was higher in the TDS > 30 mm group than in the TDS ≤ 30 mm group (75% vs. 26%, p < 0.001). There were no significant differences in length of hospital stay (LOS) (2.2 ± 0.7 vs. 2.3 ± 1.0, p = 0.329) or complication rate (10.9% vs. 14.6%, p = 0.582) between the two groups.

Conclusion

The results suggested that same-session fURS can be effectively performed with a low complication rate. A higher SFR after the first fURS can be achieved in the case of bilateral upper urinary tract stones with TDS ≤ 30 mm, and priority should be given to same-session fURS.

Optimal placement of flexible ureteral access sheath in retrograde intrarenal surgery

This study aims to explore the optimal location of flexible ureteral access sheath (f-UAS) in retrograde intrarenal lithotripsy (RIRS). RIRS model was built by AutoCAD 2011 software, and imported COMSOL 5.6 software to computer simulation. An RIRS model was constructed in vitro to analyze the distribution pattern of stone fragments and compare the weight of stone fragments carried out by the irrigation fluid when the f-UAS is in different positions. Computer simulation showed that the highest flow of irrigation fluid was in the channel of flexible ureteroscopy (f-URS) and in the lumen of f-UAS. From the f-URS to the renal collection system and then to the f-UAS, the velocity of irrigation fluid changes gradually from high-flow to low-flow and then to high-flow. When the f-URS and the f-UAS are at the same level, the irrigation fluid is always at a state of high flow during the process from f-URS to f-UAS. When the f-URS and the f-UAS are at the same level, it can increase the local intrarenal pressure (IRP) at the front of f-URS. The stone fragments are mainly sediment in the low-flow region of irrigation fluid. More stone fragments could follow the irrigation fluid out of the body when the tip of f-URS and the tip of f-UAS are at the same level (P < 0.001). The f-UAS should be brought closer to the stone in RIRS. And more stone fragments can be taken out of the body by the effect of irrigation fluid.

Causal relationship in gut microbiota and upper urinary urolithiasis using Mendelian randomization

Background

Several reports in recent years have found an association between gut microbiota and upper urinary urolithiasis. However, the causal relationship between them remains to be clarified.

Methods

Genetic variation is used as a tool in Mendelian randomization for inference of whether exposure factors have a causal effect on disease outcomes. We selected summary statistics from a large genome-wide association study of the gut microbiome published by the MiBioGen consortium with a sample size of 18,340 as an exposure factor and upper urinary urolithiasis data from FinnGen GWAS with 4,969 calculi cases and 213,445 controls as a disease outcome. Then, a two-sample Mendelian randomization analysis was performed by applying inverse variance-weighted, MR-Egger, maximum likelihood, and weighted median. In addition, heterogeneity and horizontal pleiotropy were excluded by sensitivity analysis.

Results

IVW results confirmed that class Deltaproteobacteria (OR = 0.814, 95% CI: 0.666-0.995, P = 0.045), order NB1n (OR = 0.833, 95% CI: 0.737-0.940, P = 3.15 × 10^-3), family Clostridiaceae1 (OR = 0.729, 95% CI: 0.581-0.916, P = 6.61 × 10^-3), genus Barnesiella (OR = 0.695, 95% CI: 0.551-0.877, P = 2.20 × 10^-3), genus Clostridium sensu_stricto_1 (OR = 0.777, 95% CI: 0.612-0.986, P = 0.0380), genus Flavonifractor (OR = 0.711, 95% CI: 0.536-0.944, P = 0.0181), genus Hungatella (OR = 0.829, 95% CI: 0.690-0.995, P = 0.0444), and genus Oscillospira (OR = 0.758, 95% CI: 0.577-0.996, P = 0.0464) had a protective effect on upper urinary urolithiasis, while Eubacterium xylanophilum (OR =1.26, 95% CI: 1.010-1.566, P = 0.0423) had the opposite effect. Sensitivity analysis did not find outlier SNPs.

Conclusion

In summary, a causal relationship was found between several genera and upper urinary urolithiasis. However, we still need further randomized controlled trials to validate.

The Uniform grading tooL for flexIble ureterorenoscoPes (TULIP-tool): a Delphi consensus project on standardised evaluation of flexible ureterorenoscopes

OBJECTIVE

To develop a standardised tool to evaluate flexible ureterorenoscopes (fURS).

MATERIALS AND METHODS

A three-stage consensus building approach based on the modified Delphi technique was performed under guidance of a steering group. First, scope- and user-related parameters used to evaluate fURS were identified through a systematic scoping review. Then, the main categories and subcategories were defined, and the expert panel was selected. Finally, a two-step modified Delphi consensus project was conducted to firstly obtain consensus on the relevance and exact definition of each (sub)category necessary to evaluate fURS, and secondly on the evaluation method (setting, used tools and unit of outcome) of those (sub)categories. Consensus was reached at a predefined threshold of 80% high agreement.

RESULTS

The panel consisted of 30 experts in the field of endourology. The first step of the modified Delphi consensus project consisted of two questionnaires with a response rate of 97% (n = 29) for both. Consensus was reached for the relevance and definition of six main categories and 12 subcategories. The second step consisted of three questionnaires (response rate of 90%, 97% and 100%, respectively). Consensus was reached on the method of measurement for all (sub)categories.

CONCLUSION

This modified Delphi consensus project reached consensus on a standardised grading tool for the evaluation of fURS - The Uniform grading tooL for flexIble ureterorenoscoPes (TULIP) tool. This is a first step in creating uniformity in this field of research to facilitate future comparison of outcomes of the functionality and handling of fURS.

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.

Comparison of flexible ureteroscopy in the treatment of 1-2 cm single nephrolithiasis and multiple nephrolithiasis

Objective

To compare the efficacy of flexible ureteroscopy for single urinary stones with that of multiple urinary stones.

Methods

A retrospective study was conducted on patients who underwent flexible ureteroscopy in Qilu Hospital of Shandong University from January 2016 to March 2021. Propensity score matching was used to match patients with no statistical difference in preoperative clinical data, and they were divided into solitary calculi and multiple calculi two groups. The postoperative hospital days, operation time, complications and stone free rate were compared between the two groups. And multiple stones were divided into high group (S-ReSc > 4) and non-high group (S-ReSc ≤ 4) for analysis.

Results

313 patients were counted. After propensity score matching, 198 patients were finally included in the study. There were 99 cases in the solitary stone group and the multiple stone group. There were no significant differences in postoperative hospital days, complications and stone free rate between the two groups. The operation time of patients with solitary stone group was significantly shorter than that of patients with multiple stones (65.00 min, 45.00 min VS 90.00 min, 50.00 min, P < 0.001). The SFR of high group in the multiple stones group was significantly lower than that in the non-high group (7, 58.3% VS 78, 89.7%, P = 0.013).

Conclusion

Despite the longer operation time, flexible ureteroscopy has similar outcomes in the treatment of multiple (S-Rec ≤ 4) compared to solitary calculi. Although, this doesn't apply when S-ReSc > 4.

RIRS with disposable or reusable scopes: does it make a difference? Results from the multicenter FLEXOR study

Introduction

With several single-use ureteroscopes now available, our aim was to analyze and compare data obtained globally from high-volume centers using both disposable and reusable flexible ureteroscopes and see if indeed in real-world practice either scope has a distinct advantage.

Methods

Retrospective analysis was performed on the FLEXOR registry, which was created as a TOWER group (Team of Worldwide Endourological Researchers, research wing of the Endourological Society) endeavor. Patients who underwent retrograde intrarenal surgery (RIRS) for renal stones from January 2018 to August 2021 were enrolled from 20 centers globally. A total of 6663 patients whose data were available for analysis were divided into Group 1 (Reusable scopes, 4808 patients) versus Group 2 (Disposable scopes, 1855 patients).

Results

The age and gender distribution were similar in both groups. The mean stone size was 11.8 mm and 9.6 mm in Groups 2 and 1, respectively (p < 0.001). Group 2 had more patients with >2 cm stones, lower pole stones and of higher Hounsfield unit. Thulium fiber laser (TFL) was used more in Group 2 (p < 0.001). Patients in Group 2 had a slightly higher stone-free rate (SFR) (78.22%) and a lower number of residual fragments (RFs) compared with Group 1 (p < 0.001). The need for further treatments for RF and overall complications was comparable between groups. On multivariate analysis, overall complications were more likely to occur in elderly patients, larger stone size, lower pole stones, and were also more when using disposable scopes with longer operative time. RFs were significantly higher (p < 0.001) for lower pole, larger, harder, multiple stones and in elderly.

Conclusion

Our real-world practice observations suggest that urologists choose disposable scopes for bigger, lower pole, and harder stones, and it does indeed help in improving the single-stage SFR if used correctly, with the appropriate lasers and lasing techniques in expert hands.

Role of Pediatric Ureteral Access Sheath and Outcomes Related to Flexible Ureteroscopy and Laser Stone Fragmentation: A Systematic Review of Literature

Context

Flexible ureteroscopy and laser lithotripsy (FURSL) represent a good treatment option for pediatric urolithiasis. Scarce evidence is available about the safety and efficacy of the concomitant use of a ureteral access sheath (UAS) in the setting of pediatric ureteroscopy (URS).

Objective

To acquire all the available evidence on UAS usage in pediatric FURSL, focusing on intra- and postoperative complications and stone-free rates (SFRs).

Evidence acquisition

We performed a systematic literature research using PubMed/MEDLINE, Embase, and Scopus databases. The inclusion criteria were cohorts of pediatric patients <18 yr old, submitted to URS for FURSL, reporting on more than ten cases of UAS placement. The primary outcomes were prestenting rates, operating time, ureteric stent placement rates after surgery, rates and grades of complications, ureteral injuries, and overall SFR. A total of 22 articles were selected.

Evidence synthesis

In total, 26 intraoperative and 130 postoperative complications following URS with UAS placement were reported (1.8% and 9.18% of the overall procedures, respectively). According to the Clavien-Dindo classification, 32 were classified as Clavien I, 29 as Clavien II, 43 as Clavien I or II, six as Clavien III, and one as Clavien IV. Twenty-one cases of ureteral injuries (1.59%) were noted in the whole cohort; most of them were ureteral perforation or extravasation, and were treated with a temporary indwelling ureteric stent. The overall SFR after a single URS procedure was 76.92%; after at least a second procedure, it was 84.9%.

Conclusions

FURSL is a safe and effective treatment option for pediatric urolithiasis. UAS use was associated with a low rate of ureteric injuries, mostly treated and resolved with a temporary indwelling ureteric stent.

Patient summary

We performed a systematic literature research on the utilization of a UAS during ureteroscopy for stone treatment in pediatric patients. We assessed the outcomes related to the rates of intra- and postoperative complications and the rates of efficacy of the procedure in the clearance of stones. The evidence shows a low rate and grade of complications associated with UAS placement and good stone-free outcomes. A ureteric injury may occur in 1.6% of cases, but it is usually managed and resolved with a temporary indwelling ureteric stent.

Comparison of flexible ureteroscopy and mini-percutaneous nephrolithotomy in the treatment for multiple nephrolithiasis

Objective

To compare the outcomes of flexible ureteroscopy and mini-percutaneous nephrolithotomy in the treatment for multiple nephrolithiasis in 1–2 cm size.

Methods

The clinical data of patients with multiple renal calculi in the range of 1–2 CM who underwent flexible ureteroscopy lithotripsy and percutaneous nephrolithotomy in Qilu Hospital of Shandong University from January 2016 to March 2021 were retrospectively collected and matched using propensity score matching. Then a subgrouping of the number of stones was performed. Patients were divided into Group A and Group B according to their stone numbers. Patients with no statistically significant differences in baseline data were matched to compare the safety and efficacy of the two procedures.

Results

A total of 210 patients with clinical data were collected, and the patients’ baseline data were not comparable, and 142 patients were finally included in the study after propensity score matching. There was no statistical difference in baseline data between the two groups of patients. The postoperative hospital days (3.00, 2.00 vs. 7.00, 3.00, P < 0.001), operation time (90.00, 50.00 vs. 110.00, 53.00, P = 0.018), complications (6, 6.8% vs. 14, 25.9%, P = 0.001) of patients in flexible ureteroscopy group %, P = 0.001) was significantly lower than that in the percutaneous nephrolithotomy group. There was no significant difference in stone clearance rate between the two groups (76, 86.4% vs. 42, 77.8%, P = 0.185). When the number of stones was no more than 3, the operation time (85.00, 49.00 vs. 110.00, 53.00, P = 0.005) and complications (2, 4.2% vs. 11, 29.7%, P = 0.001) of f-URS were significantly less than those of mPCNL, but when the number of stones was more than 3, there was no significant difference between the two operations.

Conclusion

For multiple nephrolithiasis within 1–2 CM, when the number of stones does not exceed 3, flexible ureteroscopy can achieve the same stone clearance rate as percutaneous nephrolithotomy, while having shorter post-operation days, operative time and fewer complications. When the number of stones is more than 3, there are no significant difference between two operations.

Identification of the Risk Factors for the Failure of Ureteral Access Sheath Placement

PURPOSE

Insertion of a ureteral access sheath (UAS) may fail in some patients in retrograde intrarenal surgery (RIRS), and this study aimed to seek preoperative risk factors for the failure of 12/14F UAS placement.

METHODS

We retrospectively analyzed 260 consecutive patients who underwent RIRS between May 2020 and March 2022 at our institution. Data on patient and stone characteristics and several computed tomography (CT)-based measurements were collected and compared between the success and failure UAS placement groups.

RESULTS

Twenty-nine (11.2%) patients failed to insert the UAS. Age, gender, height, weight, stone side, stone location, length of history, and computed tomography (CT)-based parameters were not significant differences between the two groups. Univariate logistic regression analyses showed sex (female/male) (odds ratio: 0.287 and 95% CI [0.107, 0.722], p=0.013), length of history 15-31 days (odds ratio: 0.315 and 95% CI [0.102, 0.974], p=0.045), length of history >31 days (odds ratio: 0.202 and 95% CI [0.051, 0.805], p=0.023), and diameter of the ipsilateral common iliac artery (odds ratio: 1.285 and 95% CI [1.018, 1.623], p=0.035) were associated with UAS placement.

CONCLUSION

Our study indicated that males, the short length of history, and the short diameter of the ipsilateral common iliac artery were the risk factors for the failure of UAS placement.

RISK OF OCCURRENCE AND WAYS TO IMPROVE THE TREATMENT OF UROLITHIASIS IN PATIENTS WITH A SINGLE KIDNEY

OBJECTIVE

The aim: To summarize the state of the problem of urolithiasis in patients with a single kidney and consider current views on improving its treatment based on the analysis of world literature.

PATIENTS AND METHODS

Materials and methods: The study conducted a thorough analysis of modern scientific literature sources in the international scientometric database, which highlighted the development of urolithiasis in patients with a single kidney and the peculiarities of its treatment. The main ways to improve treatment are identified. A critical assessment of the achievements and shortcomings of various surgical treatments. The authors' own developments are presented in the article.

CONCLUSION

Conclusions: The topographic position of the kidney in the retroperitoneal space affects not only the occurrence of pathological processes in the kidney, but also the surgical strategy in the treatment of nephrolithiasis. Percutaneous nephrolithotomy is the main treatment for large (> 2 cm) or complex kidney stones. Patients with a single kidney are more prone to bleeding with PCNL treatment than patients with bilateral kidneys because they have an increased thickness of the renal parenchyma as a result of compensatory hypertrophy. RIRS is a reliable choice for patients with a single kidney who is contraindicated in PCNL.