Role of pelvicalyceal anatomy in the outcomes of retrograde intrarenal surgery (RIRS) for lower pole stones: outcomes with a systematic review of literature

Pelvicalyceal anatomy and stone related factors as predictors of stone free rate in retrograde intrarenal surgery for lower calyceal stone

INTRODUCTION

The objective of the present study is to evaluate the various pelvi-calyceal anatomy related and stone related parameters and their influence on stone free rate in retrograde intrarenal surgery for lower calyceal stones.

METHODS

The retrospective analysis of records of 206 patients who underwent retrograde intrarenal surgery for lower calyceal stones from December 2021 and November 2023.The patients were divided into two groups: stone free group and residual stone group. Various factors like patients' characteristics, stone size, volume, numbers, density, infundibular width, infundibulopelvic angle, operative time, lasing time, type of laser, and retreatment rate were compared between two groups.

RESULTS

The mean stone size in stone free group was 1.1 ± 0.7 cm whereas in residual stones group was 1.7 ± 0.4 cm (p = 0.03). Overall stone free rate was 62.1% (128/206) whereas residual stone rate was 37.9% (78/206). In stone-free group only 2.3% (3/128) of the patients had an acute infundibulopelvic angle ⩽ 30° whereas in the residual stones group an acute infundibulopelvic angle ⩽ 30° was found in 58.9% (46/78) of the patients (p < 0.001). Patients with an infundibulopelvic angle ⩽ 30°, 93.8% (46/49) had residual stones, whereas infundibulopelvic angle > 30° only 20.1% (32/157) had residual stones (p < 0.001). Multivariate logistic regression analysis has demonstrated that Infundibulopelvic angle and stone size were the only significant factors in predicting stone free rate for lower calyceal stone.

CONCLUSION

Infundibulopelvic angle and stone size have significant impact on the stone free rates in retrograde intrarenal surgery for lower calyceal stones.

Comparative analysis of scoring systems for patients undergoing retrograde intrarenal surgery with isolated lower calyx stones

PURPOSE

It is critical to provide patients with accurate information on potential surgical outcomes during the preoperative phase. Several scoring systems have been developed for this specific purpose. This study aimed to examine the predicted efficacy of scoring systems in patients with isolated lower calyx stones who underwent retrograde intrarenal surgery (RIRS).

METHODS

We performed a retrospective analysis of 85 patients who underwent RIRS for lower calyx stones between 2016 and 2023. The study computed each participant's Resorlu-Unsal Stone score (RUSS), R.I.R.S. scoring system score, Modified Seoul National University Renal Stone Complexity (S-ReSC) score, S.T.O.N.E. score, Ito's nomogram, and T.O.HO score. Residual stones less than 4 mm were classified as clinically insignificant residual fragments (CIRFs) and regarded as successful. Following that, we used receiver-operating characteristic (ROC) curves to compare various scoring systems' success predictions.

RESULTS

The median scores for RUSS, R.I.R.S. scoring system, Modified S-ReSC, S.T.O.N.E., Ito's nomogram, and T.O.HO score were 1 (1), 7 (2), 2 (0), 11 (1), 18 (4), and 7 (1), respectively. When CIRF cases were included, the stone-free rate increased to 80%. Only Ito's nomogram from scoring systems has a statistically significant cut-off value for success in ROC analysis (p = 0.021). In multivariate analysis, stone volume and preoperative hydronephrosis were associated with success (p = 0.004 and p = 0.035, respectively).

CONCLUSION

In the multivariate analysis, none of the scoring systems were significantly associated with success. Hence, a new scoring system must be developed exclusively for patients with isolated lower pole stones undergoing RIRS.

Relationship between stone volume, average CT value and operation time and efficiency before ureteral soft lens laser lithotripsy

BACKGROUND

Soft ureteroscopic holmium laser lithotripsy is becoming increasingly popular as the preferred method for treating mid-to-lower ureteral stones. Studies have indicated that the size, composition, hardness, and fragility of the stones can impact the treatment's effectiveness.

OBJECTIVE

To explore the relationship between stone volume, average CT value and operation time and efficiency before ureteral soft lens laser lithotripsy.

METHODS

Our study on 126 patients undergoing ureteroscopic holmium laser lithotripsy for ureteral calculi from May 2020 to January 2022 categorized them into groups based on stone volume and CT value. We compared surgical outcomes and analyzed correlations between stone characteristics, operation parameters, and stone clearance rate to identify independent risk factors influencing treatment efficacy.

RESULTS

Group A demonstrated significantly shorter operation durations and lower blood loss compared to Group B, along with higher single stone clearance rates and fewer postoperative complications. Similarly, Group C exhibited shorter operation times, reduced blood loss, higher stone clearance rates, and lower complication rates than Group D. Preoperative stone volume and CT value correlated positively with operation time and stone clearance rate, with both factors identified as independent risk factors affecting ureteral stone clearance following holmium laser lithotripsy.

CONCLUSION

The stone volume and average CT value before ureteral soft lens laser lithotripsy show a positive correlation with operation time and efficiency, indicating that larger stone volumes and higher CT values lead to slower lithotripsy speeds and reduced operation efficiency. Furthermore, preoperative stone volume and average CT value are identified as independent risk factors for residual stones.

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

OBJECTIVES

To compare the clinical efficacy and safety of single-use and reusable digital flexible ureteroscopy for the treatment of lower pole stones.

METHODS

We enrolled 135 patients underwent reusable flexible ureteroscopy (FURS) and 78 patients underwent single-use digital FURS. Demographic, clinical variables, anatomical parameters of the lower calyx and perioperative indicators were compared in the two groups.

RESULTS

Thirty-six patients in the infundibuloureter angle (IPA) < 45° subgroup had a mini-percutaneous nephrolithotomy (mini-PCNL), including 25 patients in the reusable FURS group and 11 patients in the single-use FURS group. The demographic and clinical variables in the two FURS groups were comparable. There was no statistical difference in the success rate of stone searching (P > 0.05). In terms of the success rate of lithotripsy, there was also no statistical difference in the IPA ≥ 45° subgroup (P > 0.05), whereas single-use FURS was superior in the IPA < 45° subgroup (χ2 = 6.513, P = 0.011). The length of the working fiber in the reusable FURS and single-use FURS groups was 3.20 ± 0.68 mm and 1.75 ± 0.47 mm, respectively (t = 18.297, P < 0.05). The use of a stone basket in the reusable FURS (31/135, 23.0%) was significantly higher than that in the single-use FURS (8/78, 10.3%) (χ2 = 5.336, P = 0.021). Compared with the reusable FURS group, the single-use FURS group had shorter operation times (P < 0.05) and higher stone-free rate (SFR) (χ2 = 4.230, P = 0.040). There was no statistical difference in the intraoperative transfer of mini-PCNL and postoperative complications between the two groups (P > 0.05).

CONCLUSIONS

Single-use and reusable FURS are alternative methods for removal of lower pole stones (i.e., 2 cm or less). Single-use FURS has a high success rate of lithotripsy, shorter operation time, and high stone-free rate.

Effect of infundibulopelvic angle on outcomes of ureteroscopy: a systematic review and meta-analysis

PURPOSE

The infundibulo-pelvic angle (IPA) is reportedly a predictor of successful ureteroscopy for lower pole renal stones, however there is uncertainty at which IPA success is likely. We therefore aimed to perform a meta-analysis and determine at which the angle of likely success and failure.

METHODS

We performed a systematic review and meta-analysis as per Cochrane guidelines in accordance to the PRISMA statement. The review was registered with PROSPERO prior to commencement (ID: CRD42022296732). We included studies reporting on outcomes of ureteroscopy for lower pole stones, with IPA. We excluded patients undergoing alternative treatments for lower pole stones, anatomical abnormalities and studies with < 10 patients. We assessed bias with the Newcastle-Ottawa scale. We performed meta-analysis in R, and summarised the findings as per GRADE.

RESULTS

Overall, there were 13 studies included, with 10 included for meta-analysis. These studies covered n = 1964 patients (71% stone free). Overall, the stone free patients had a significantly less acute mean IPA (52o ± 9o), compared to the non-stone free patients (39o ± 7o), on meta-analysis (REM MD = -13.0, 95% CI: -18.7 to -7.2, p < 0.001). On examination of forest plots, at IPA < 30o no patients were stone free, whilst > 50o all were stone free. Risk of bias was moderate, and certainty of evidence was 'very low'.

CONCLUSION

With a very low certainty of evidence, we demonstrate that at an IPA of < 30o no patient is stone free, whilst > 50o all patients (in this review) are stone free. More evidence is therefore needed.

Impact of previously failed extracorporeal shock wave lithotripsy on ureterorenoscopy outcomes in upper urinary tract stones: a prospective comparative study

OBJECTIVE

We sought to prospectively evaluate the impact of previously failed SWL on subsequent URS outcomes in the treatment of upper urinary tract stones.

MATERIALS AND METHODS

Between May 2021 and May 2023, one hundred thirty-six patients with proximal ureteral stones < 1.5 cm and renal stones < 2.5 cm who were candidates for URS were prospectively assigned to a non-SWL group, which included patients without a history of failed SWL before URS, and a post-SWL group, which included patients with a history of failed SWL before URS. The success rate was the primary outcome. The perioperative data of the two groups were compared.

RESULTS

The stone-free rate was 83.3% in the post-SWL group versus 81.3% in the non-SWL group, and 8.3% in the post-SWL group versus 9.4% in the non-SWL group had clinically insignificant residual fragments. There was no significant difference in the stone-free rate or success rate between the groups. No significant differences in intraoperative fluoroscopy time, operative time, intraoperative stone appearance, perioperative complications, or the presence of embedded fragments in the ureteral mucosa were detected between the two groups.

CONCLUSION

Compared with patients who underwent primary URS, patients who underwent salvage URS for upper urinary tract stones had similar stone-free rates, success rates, operative times, fluoroscopy times, and complication rates without any significant differences.

Comparative study between retrograde intrarenal surgery and ultrasound- guided shock wave lithotripsy for treatment of 1 to 2 cm radiolucent lower calyceal stones

Objectives

The objective is to compare the safety and efficacy of retrograde intrarenal surgery (RIRS) and ultrasound-guided (US-guided) shock wave lithotripsy (SWL) for the treatment of radiolucent lower pole calculi of 1-2 cm.

Materials and Methods

This prospective randomized study was performed at our tertiary care urology institute of Benha University Hospitals; cases were randomized either to undergo RIRS (Group A) or US-guided SWL with a triple focus system (Group B). The safety and effectiveness of both therapies were compared using new criteria for stone-free rate (SFR): Grade A (absolutely stone free), Grade B (≤2 mm fragments), and Grade C (>2 mm up to 4 mm fragments), fluoroscopy time, operative time, auxiliary procedures, retreatment, and complications.

Results

Out of 100 patients, 92 were eligible for this study. RIRS had a higher SFR of 88.9% compared to SWL, 72.3% (P = 0.045). Furthermore, stone-free classification significantly differed between the studied groups (P < 0.001), with Grade A being significantly higher in Group A. Conversely, Grades B and C were lower in Group A. On the other hand, operative and fluoroscopy times were significantly reduced with SWL (P = 0.004 and < 0.001, respectively). While complications did not significantly differ between the two groups (P = 0.340), a significant distinction was observed in terms of the Clavien-Dindo classification.

Conclusions

RIRS is an effective and safe option for treating radiolucent lower calyceal stones of ≤2 cm, with a greater SFR and lower need for auxiliary operations. However, Sono SWL is a cost-effective alternative that can achieve a comparable success rate after retreatment sessions.

Comparative Analysis of Super-Mini Percutaneous Nephrolithotomy and Retrograde Intrarenal Surgery for the Management of Renal Calculi ≤2 cm Among Somali Population

Background: Limited data have explored the efficacy of super-mini percutaneous nephrolithotomy (SMP) and retrograde intrarenal surgery (RIRS) in managing ≤2 cm renal calculi. This study aims to comprehensively evaluate the safety and effectiveness of SMP compared with RIRS. Methods: This prospective cohort study investigated 210 patients with renal calculi (≤2 cm) undergoing SMP or RIRS, randomly recruited over 4 years. In total, 51.4% underwent SMP and 48.6% underwent RIRS. Results: The mean patient age was 31.3 ± 14.7 years; 56.7% were men, mean stone size of 1.3 ± 0.28 cm, and stone hardness of 1190.1 ± 352.83 Hounsfield units. Pearson's correlation indicated negative correlations for SMP with hospital stays (r = -0.138, p = 0.046), operating time (r = -0.519, p < 0.001), and stone-free rate (SFR) (r = -0.161, p = 0.020); and a positive correlation with a postoperative ureteral catheter (r = +0.389, p < 0.001). With regard to RIRS, the study shows a positive correlation with hospital stay (r = +0.138, p = 0.046), operating time (r = +0.519, p < 0.001), and SFR (r = +0.161, p = 0.020); and a negative correlation with postoperative ureteral catheter (r = -0.389, p < 0.001). Logistic regression, using SMP as the reference, RIRS was associated with β = +0.31, and 1.20 (95% confidence interval [CI], 1.14-1.27, p ≤ 0.001) risk of operation duration and β = +0.37, 1.44 (95% CI, 1.00-2.07, p = 0.047) risk of longer hospital stay. Conclusion: This study investigates the suitability of SMP and RIRS for treating renal calculi ≤2 cm. SMP demonstrated superior efficacy with significantly shorter operating times and reduced hospital stays, suggesting potential advantages for managing lower volume renal stones.

Kidney collecting system anatomy applied to endourology - a narrative review

OBJECTIVE

To evaluate the surgical anatomy of the kidney collecting system through a narrative review of the literature, highlighting its importance during diagnosis and its approach during surgical procedures for the treatment of renal stones.

MATERIAL AND METHODS

We carried out a review about the anatomy of the kidney collecting system. We analyzed papers published in the past 40 years in the databases Pubmed, Embase and Scielo, and we included only papers in English and excluded case reports, editorials and opinions of specialists.

RESULTS

Renal collecting system could be divided in four groups: A1 - kidney midzone (KM), drained by minor calyx that are dependent on the superior or the inferior caliceal groups; A2 - KM drained by crossed calyx, one draining into the superior caliceal group and another draining into the inferior caliceal group; B1 - KM drained by a major caliceal group independent of both the superior and inferior groups; and B2 - KM drained by minor calyx entering directly into the renal pelvis. Some details and anatomic variations of the collecting system are related to clinical and radiological aspects, particularly perpendicular calyces, interpyelocalyx space, position of calyces in relation to renal border, classification of the renal collecting system, infundibular diameter and the angle between the lower infundibulum and renal pelvis.

CONCLUSION

The knowledge of intra-renal collecting system divisions and variations as the angle between the renal pelvis and lower infundibula, position of the calices in relationship with renal edge and the diameter and position of the calyces are important for the planning of minimally invasive renal surgeries.

Has fluoroless endourology (URS and PCNL) come of age? Evidence from a comprehensive literature review

INTRODUCTION

Radiation via the use of imaging is a key tool in management of kidney stones. Simple measures are largely taken by the endourologists to implement the 'As Low As Reasonably Achievable' (ALARA) principle, including the use of fluoroless technique. We performed a scoping literature review to investigate the success and safety of fluoroless ureteroscopy (URS) or percutaneous nephrolithotomy (PCNL) procedures for the treatment of KSD.

METHODS

A literature review was performed searching bibliographic databases PubMed, EMBASE and Cochrane library, and 14 full papers were included in the review in accordance with the PRISMA guidelines.

RESULTS

Of the 2535 total procedures analysed, 823 were fluoroless URS vs. 556 fluoroscopic URS; and 734 fluoroless PCNL vs. 277 fluoroscopic PCNL. The SFR for fluoroless vs. fluoroscopic guided URS was 85.3% and 77%, respectively (p=0.2), while for fluoroless PCNL vs. fluoroscopic group was 83.8% and 84.6%, respectively (p=0.9). The overall Clavien-Dindo I/II and III/IV complications for fluoroless and fluoroscopic guided procedures were 3.1% (n=71) and 8.5% (n=131), and 1.7% (n=23) and 3% (n=47) respectively. Only 5 studies reported a failure of the fluoroscopic approach with a total of 30 (1.3%) failed procedures.

CONCLUSION

The ALARA protocol has been implemented in endourology in numerous ways to protect both patients and healthcare workers during recent years. Fluoroless procedures for treatment of KSD are safe and effective with outcomes comparable to standard procedures and could become the new frontier of endourology in selected cases.

The effect of percussion, diuresis and inversion therapy on RIRS success for lower renal pole stones

Introduction

Inversion of the patient, forced diuresis after hydration, and mechanical percussion technique was developed for lower renal pole (LRP) stones with extracorporeal shock wave (ESWL). In this study, we aimed to analyze the effect of percussion, diuresis and inversion (PDI) therapy on the success rates of retrograde intrarenal surgery (RIRS) for the LRP stones.

Material and methods

114 patients who underwent RIRS for LRP stones <2cm were included in this study. Patients' demographic, clinical, radiological and anatomical features and success status were recorded prospectively. The patients were divided into two groups. One group received RIRS procedure only (non-PDI group) and the other group received PDI therapy after the RIRS procedure (PDI group).

Results

PDI was performed to 60 (52.6%) patients, and not performed to 54 (47.4%) patients. The success rate (58.3%) for the PDI group was higher than the non-PDI group (25.9%), and this difference was statistically significant (p <0.001). In multivariate logistic regression analysis, stone size (OR = 1.306; 95% CI = 1.019-1.674; p <0.001), IU (OR = 1.702; 95% CI = 1.383-2.096; p <0.001) and not performing PDI therapy (p <0.001) OR = 9.455; 95% Cl = 2.426-10.853; p = 0.001) were revealed to be independent risk factors for failure.

Conclusions

PDI therapy increases the success rates of RIRS performed for the LRP stones.

2022 Recommendations of the AFU Lithiasis Committee: Ureteroscopy and ureterorenoscopy

Technical advances, including miniaturization, have improved the deflection and optical performance of the ureteroscopes, and the availability of dedicated disposable devices have led to their increasing use for kidney and ureteral stone management. Ureterorenoscopy brings diagnostic evidence through the endoscopic description of stones and renal papillary abnormalities. Currently, intracorporeal lithotripsy during ureterorenoscopy is based on laser sources. Routine ureteral stenting is not necessary before ureterorenoscopy, especially because preoperative stenting for>30 days is considered as an independent risk factor of infection. Ureteral access sheaths allow the easy and repeated access to the upper urinary tract and thus facilitate ureterorenoscopy. Their use improves vision, decreases intrarenal pressure, and possibly reduces the operative time, but they may cause ureteral injury. METHODOLOGY: These recommendations were developed using two methods: the Clinical Practice Recommendation (CPR) method and the ADAPTE method, depending on whether or not the question was considered in the European Association of Urology (EAU) recommendations (https://uroweb.org/guidelines/urolithiasis [EAU 2022]) and their adaptability to the French context.

Flexible ureteroscopy for lower pole calculus: is it still a challenge?

PURPOSE

Flexible ureteroscopy (fURS) is steadily gaining popularity in the management of renal calculi, including those located in the lower pole (LP). Due to difficulty in accessing to the LP of kidney in minority of cases with fURS and reports of lower stone-free rate (SFR), it is still considered as a challenge in selected cases. The purpose of the review was to analyze the various aspects of fURS for LP stones.

METHODS

An extensive review of the recent literature was done including different factors such as anatomy, preoperative stenting, stone size, flexible scopes, types of lasers, laser fibers, suction, relocation, stone-free rates, and complications.

RESULTS

The significance of various lower pole anatomical measurements remain a subject of debate and requires standardization. Recent improvements in fURS such as single-use digital scopes with better vision and flexibility, high power laser, thulium fiber laser, smaller laser fiber, and accessories have significantly contributed to make flexible ureteroscopy  more effective and safer in the management of LP stone. The utilization of thulium fiber lasers in conjunction with various suction devices is being recognized and can significantly improve SFR.

CONCLUSIONS

With the significant advancement of various aspects of fURS, this treatment modality has shown remarkable efficacy and gaining widespread acceptance in management of LP kidney stones. These developments have made the fURS of LP stones less challenging.

Efficacy and safety of minimally invasive percutaneous nephrolithotomy versus retrograde intrarenal surgery in the treatment of upper urinary tract stones (> 1 cm): a systematic review and meta-analysis of 18 randomized controlled trials

BACKGROUND

The advantages and disadvantages of retrograde intrarenal surgery (RIRS) and minimally invasive percutaneous nephrolithotomy (mPCNL) for treatment of upper urinary tract calculi have not been conclusively determined.

METHODS

In this meta-analysis, We comprehensively evaluated the performance of the two surgical approaches in treatment of upper urinary calculi. We searched the Pubmed, Embase, Cochrane and Web of science databases for randomized controlled trial (RCT) articles on RIRS and mPCNL upto December 2022. Data were extracted by two independent reviewers and subjected to the meta-analysis using the Stata 15.1 software (StataSE, USA).

RESULTS

A total of 18 eligible RCTs involving 1733 patients were included in this study. The meta-analysis revealed that mPCNL of 1-2 cm or 2-3 cm stones had a higher stone clearance rate (RR:1.08, 95%CI (1.03, 1.14), p = 0.002) and shorter operation time (WMD : -10.85 min, 95%CI (-16.76, -4.94), p<0.001). However, it was associated with more hospital stay time (WMD :1.01 day, 95%CI(0.53, 1.5), p<0.001), hemoglobin drops (WMD :0.27 g/dl, 95%CI (0.14, 0.41), p<0.001), blood transfusion rate (RR:5.04, 95%CI(1.62, 15.65), p = 0.005), pain visual analogue score (WMD:0.75, 95%CI (0.04, 1.46), p = 0.037), hospital costs (SMD :-0.97, 95%CI (-1.19, -0.76), p<0.001) and major complications (RR:1.89, 95%CI(1.01, 3.53), p = 0.045).

CONCLUSION

Therefore, in terms of surgical effects and operation time, mPCNL is superior to RIRS, but is inferior with regards to other perioperative parameters. These factors should be fully considered in clinical decision making.

Residual fragment size following retrograde intrarenal surgery: a critical evaluation of related variables

Given the limited data on the predictive factors of residual kidney stone size after flexible ureteroscopy (fURS), this study aims to investigate the variables affecting residual stone size. The medical records of 642 patients without complications being treated for kidney stones with fURS between July 2014 and May 2022 were reviewed retrospectively, and the information of the 170 patients in whom residual stones were found was recorded. In addition to patient-specific factors and stone characteristics, length of postoperative hospital stay, postoperative fever, and preoperative antiaggregant use were evaluated. Of the 170 patients ultimately included in the study. The mean age was 51.56 (± 14.70). The mean stone size was 14.01 mm (± 5.75), the mean residual stone size was 7.04 mm (± 2.51), and the mean stone density was 829 Hounsfield units (± 395.06). The mean infundibulopelvic angle (IPA) was 49.37º (± 15.37), and 41.2% of the stones were non-opaque. The mean parenchymal thickness was 22.88 mm (± 5.55). 34 patients were on antiaggregant therapy. Preoperative stone size increases in stone density and decreases in IPA were found to be correlated with increase residual stone size (p < 0.001, p < 0.001, and p < 0.001, respectively). In addition, larger residual stones were observed after the fURS procedure in patients using anticoagulants and those without hydronephrosis (p = 0.02 and p = 0.016, respectively). Use of reliable predictive factors to forecast residual stone size after fURS may help to inform those treated and enable urologists to design rational surgical strategies.

A Feasibility Study on Clinical Utility, Efficacy and Limitations of 2 Types of Flexible and Navigable Suction Ureteral Access Sheaths in Retrograde Intrarenal Surgery for Renal Stones

OBJECTIVE

To evaluate stone-free rate, device maneuverability, and complications after retrograde intrarenal surgery (RIRS) using 2 different sizes of flexible and navigable suction ureteral access sheaths (FANS).

METHODS

A retrospective analysis was performed for patients who underwent RIRS for renal stones of any size, number, and location between November 2021 and October 2022. Group 1 had FANS of 12 French. Group 2 had FANS of 10 French. Both sheaths have a Y-shaped suction channel. Tip of 10 French FANS has 20% more flexibility. Lithotripsy was achieved using either thulium fiber or high-power holmium lasers. A 5-point Likert scale was used to assess the performance of each sheath.

RESULTS

There were 16 patients in Group 1 and 15 patients in Group 2. Baseline demographics and stone parameters were similar. Four patients in Group 2 had the same session bilateral RIRS. Sheath insertion was successful in all renal units but one. Ten French FANS had a higher percentage of excellent scores for ease of use, manipulation, and visibility. Neither of the sheaths had an average or difficult rating for all evaluation scales. A fornix rupture requiring prolonged stenting occurred in group 2. All patients were discharged within 24 hours of surgery. One patient in each group visited the emergency department (analgesic treatment). There were no infectious complications. At 3 months, a computed tomography scan showed that the absence of residual fragments >2 mm was significantly higher in Group 2 (94.7% vs 68.8%, P = 0.01).

CONCLUSION

The 10 Fr FANS showed a higher stone-free rate. There was no infectious complication using both sheaths.

Evaluation of validity and reliability of novel rapid measurement for infundibulopelvic angle: a comparison with PACS system

BACKGROUND

For patients with lower pole renal calculi (LPC), preoperative evaluation of infundibulopelvic angles (IPA) is of great significance; however, conventional measuring method is often inconvenient in clinical setting. Here we introduce a rapid novel method using built-in inclinometer in smartphone which is often used in anatomical parameters evaluating to implement the measurement of IPA.

MATERIALS AND METHODS

The randomized, self-controlled study on evaluating inclinometer application measured IPA on urography films collected from enrolled LPC patients. Results of statistical analysis for its validity and reliability compared to conventional PACS system are reported. Predictive performance of postoperative stone-free rates by IPA measured with the novel method was also evaluated in this study.

RESULTS

Bland-Altman plot result shows that there is favorable agreement between IPA values of these two methods. The time required to utilize the PACS was considerably greater than time required to take similar measure using smartphones. The precision-recall curve (PRC) indicates that the new method has similar predictive performance for postoperative clearance rates as PACS.

CONCLUSIONS

In summary, measurement of IPA implemented by integrated inclinometer of smartphone is rapid, convenient, accurate and reliable in evaluating renal anatomy parameters of LPC patients.

Minimally invasive nephrolithotomy versus retrograde intrarenal surgery in surgical management of Lower calyceal stones: a systematic review with meta-analysis

OBJECTIVE

The efficacy and safety of minimally invasive nephrolithotomy (MPCNL) versus retrograde intrarenal surgery (RIRS) was assessed for lower calyceal (LC) stones.

METHODS

Our team conducted a systematic literature search up to December, 2022, using PUBMED, EMBASE and the Cochrane Library. The study was registered in PROSPERO, CRD 42021247197. Randomized controlled trials evaluating the efficacy and safety of MPCNL versus RIRS for LC stones were collected. Heterogeneity among the studies was assessed using the χ 2 test based on the Q and I2 tests. Pooled effect sizes were calculated using a fixed model if I2 is less than 50%; otherwise, a random-effects model was chosen. The primary outcomes were the 3-month stone-free rate (3SFR) and total complications, while the secondary outcomes were the operating time, hospital stay, haemoglobin reduction, bleeding, postoperative fever and complications with the Clavien-Dindo system. A subgroup analysis of 10-20 mm LC stones was also designed.

RESULTS

A total of 7 peer-reviewed trials comprising 711 patients were identified. No statistical differences were observed in the heterogeneity results of the 3SFR or total complications ( P >0.1, I2 < 50%). Compared with RIRS, MPCNL had an unfavourable safety profile, resulting in total complications [odds ratio (OR): 1.87 (95% CI: 1.05, 3.33); P =0.03], haemoglobin reduction [OR: 0.81 (95% CI: 0.15, 1.47); P =0.02] and complications with Grade I [OR: 5.52 (95% CI: 1.34, 22.83); P =0.02] but an improved efficacy and 3SFR [OR: 2.43 (95% CI: 1.48, 3.97); P =0.0004]. As for the 10-20 mm LC stones, compared with RIRS, MPCNL also had an unfavourable safety profile, resulting in total complications [OR: 2.47 (95% CI: 1.20, 5.07); P =0.01], complications with Grade I [OR: 4.97 (95% CI: 0.99, 25.01); P =0.05] and an increased hospital stay [OR: 2.46 (95% CI: 2.26, 2.66); P =0.00001] but an improved efficacy and 3SFR {OR: 3.10 (95% CI: 1.61, 5.99); P =0.0008]. The efficacy effect of MPCNL and safety effect of RIRS were nearly equal for both stones sized less than 20 mm (number needed to treat = 17, number needed to harm = 20) and stones sized 10-20 mm (number needed to treat = 20, number needed to harm = 13). No statistical difference was found between the MPCNL and RIRS groups for the rest of outcomes.

CONCLUSION

Both MPCNL and RIRS are safe and effective management methods. Moreover, compared with RIRS, MPCNL had an unfavourable safety profile but improved efficacy for LC stones of ≤20 mm or 10-20 mm, and the differences were statistically significant. The relative profit of efficacy of MPCNL was similar to the relative profit of safety of RIRS.

Endourological Options for Small (< 2 cm) Lower Pole Stones - Does the Lower Pole Angle Matter?

PURPOSE OF REVIEW

Small renal stones in the lower pole are often difficult to treat. The angle of the lower pole to the renal pelvis (lower pole angle) is a limiting factor to rendering the patient stone free. This review explores the definitions of the lower pole angle, the various treatment options available, and how outcomes are influenced by the angle.

RECENT FINDINGS

It is clear the lower pole angle definition varies widely depending on described technique and imaging modality. However, it is clear that outcomes are worse with a steeper angle, especially for shock wave lithotripsy and retrograde intrarenal surgery (RIRS). Percutaneous nephrolithotomy has similar reported outcomes to RIRS, and there is limited evidence it may be superior for steeper angles over RIRS. Lower pole stones can be technically challenging and adequate assessment prior to choosing operative approach is key.

The efficacy of retrograde intra-renal surgery (RIRS) for lower pole stones: results from 2946 patients

PURPOSE

To evaluate the perioperative outcomes of retrograde intra-renal surgery (RIRS) for lower pole stones (LPS) and factors affecting stone-free rate (SFR).

METHODS

Data from 20 centers were retrospectively reviewed. Inclusion criteria were adult patients, normal renal anatomy, and LPS. Exclusion criteria were bilateral surgery, concomitant surgery for ureteral stones. SFR was defined as a single residual fragment (RF) ≤ 2 mm and evaluated 3-months after surgery. A multivariable logistic regression analysis was performed to assess factors associated with RF. Statistical significance was set at p value < 0.05.

RESULTS

2946 patients were included. Mean age and stone size were 49.9 years 10.19 mm, with multiple LPS in 61.1% of cases. Total operation and laser time were 63.89 ± 37.65 and 17.34 ± 18.39 min, respectively. Mean hospital stay was 3.55 days. Hematuria requiring blood transfusion and fever/urinary infections requiring prolonged antibiotics occurred in 6.1% and 169 5.7% of cases, while sepsis with intensive-care admission in 1.1% of patients. On multivariate analysis, Multiple stones (OR 1.380), stone size (OR 1.865), and reusable ureteroscopes (OR 1.414) were significantly associated with RF, while Thulium fiber laser (TFL) (OR 0.341) and pre-stenting (OR 0.750) were less likely associated with RF.

CONCLUSIONS

RIRS showed safety and efficacy for LPS with a mean diameter of 10 mm. This procedure can achieve a satisfactory SFR in pre-stented patients with a single and smaller stone, particularly with TFL use.

The Role of 12/14F Ureteral Access Sheath in Flexible Ureteroscopy for Moderate Nephrolithiasis

INTRODUCTION

The aim was a retrospective analysis of 12/14F ureteral access sheath (UAS) usage on perioperative outcomes in patients with moderate nephrolithiasis (MN). MN was defined as a maximum of two unilateral kidney stones with a maximum stone diameter of 6-10 mm.

MATERIAL AND METHODS

We conducted a monocentric retrospective univariate and multivariate analysis of flexible ureteroscopies (fURS) performed for MN between 01/2014 and 12/2018.

RESULTS

A total of 402 fURS were performed in patients with urolithiasis; 112 MN cases underwent further analysis. UAS was successfully applied in 33 MN cases [33/112 (29.46%)]. UAS was inserted regardless of the maximum kidney stone diameter and the presence of multiple kidney stones (p > 0.05). Univariate analysis revealed a prolonged median operation time (UAS: 94 min, non-UAS: 74 min, p = 0.04) and median fluoroscopy time (UAS: 75 s, non-UAS: 57.5 s, p = 0.04) in the UAS cohort. These differences were not confirmed on multivariate logistic regression.UAS was not associated with better stone-free rates in either the univariate or multivariate analysis (UAS: 26/33, non-UAS: 61/79, p = 1.0) nor with the occurrence of Clavien-Dindo ≥2 complications (UAS: 3/33, non-UAS: 9/79, p = 0.98) or median length of hospital stay (UAS: 2 days, non-UAS: 2 days, p = 0.169).

CONCLUSION

We identified no statistical benefits from the usage of 12/14F UAS for MN. As no relevant UAS-associated complications were documented, both strategies (with and without UAS) are feasible.

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.

Unfavorable factors in accessing the pelvicalyceal system during retrograde flexible ureteroscopy (fURS)

Flexible ureteroscopy (fURS) is a well-established procedure for treating multiple upper-urinary tract pathologies, particularly renoureteral lithiasis. Endoscopes have undergone significant advancements, including miniaturization, improved optics, and increased maneuverability. In addition, advancements in accessory instruments, such as the performance of laser fibers, guidewires, and extraction probes, have played a significant role in improving the overall performance of flexible ureteroscopy procedures. However, despite these advancements, unique circumstances can make achieving optimum results during flexible ureteroscopy challenging. These include congenital renal anomalies (horseshoe kidneys, ectopic kidneys, rotation anomalies), as well as the unique intrarenal anatomy (infundibulopelvic angle, infundibular length) or the specifications of the endoscope in terms of maneuverability (active and passive deflection). This review explored challenging scenarios during flexible ureteroscopy procedures in the pyelocaliceal system.

Role of Preoperative Ureteral Stent on Outcomes of Retrograde Intra-Renal Surgery (RIRS) in Children. Results From a Comparative, Large, Multicenter Series

OBJECTIVE

To assess outcomes of pre-stenting versus non-pre-stenting in children undergoing retrograde intrarenal surgery (RIRS) for intrarenal stones.

METHODS

Children/adolescent with kidney stones undergoing RIRS in 9 centers between 2015 and 2020 were retrospectively reviewed.

EXCLUSION CRITERIA

ureteral lithotripsy, bilateral procedures. Stone-free status was evaluated at 3-month and defined as a single residual fragment (RF) ≤2 mm/absence of multiple fragments. Patients were divided into two groups (Group 1 no-prestenting; Group 2 prestenting). Student's, Chi-square and Fisher's exact test was used to assess difference between groups. Univariable and multivariable logistic regression analysis were performed to predict RF. Statistical significance: P-value <0.05.

RESULTS

Three hundred eighty-nine children/adolescents were included (192 patients in Group 1). Prestented patients were younger compared with non-prestented (mean age 8.30 ± 4.93 vs 10.43 ± 4.30 years, P < 0.001). There were no differences in stone characteristics (number, size, locations). Lasing and total surgical time were similar. Urinary tract infections were more prevalent in Group 2 (10.7%) compared to Group 1 (3.7%, P = 0.016). Sepsis occurred in 2.1% of patients in Group 2 and no patient in Group 1 (P = 0.146). 30.7% patients in Group 1 and 26.4% in Group 2 had RF (P = 0.322). In univariate logistic regression analysis, stone size was associated with RF (OR 1.12 95%CI 1.06-1.18, P < 0.001), whereas Thulium fiber laser with a lower incidence (OR 0.24 95%CI 0.06-0.69, p=0.020). Multivariate logistic regression analysis showed that stone size was associated with RF (OR 1.20 95%CI 1.08-1.36, P = 0.001).

CONCLUSIONS

RIRS showed similar stone-free rate in pre and non-prestented children/adolescents, although prestented patients were younger. A higher risk of post-operative infections was reported in prestented patients.

Comparison and Evaluation of Outcomes of Ureteroscopy and Stone Laser Fragmentation in Extremes of Age Groups (≤10 Years and ≥80 Years of Age): A Retrospective Comparative Analysis of over 15 Years from 2 Tertiary European Centres

AIM

To assess and compare the outcomes associated with ureteroscopy and laser fragmentation (URSL) for extremes of age group (≤10 and ≥80 years).

METHODS

Retrospective consecutive data were collected from two European centres for all paediatric patients ≤10 undergoing URSL over a 15-year period (group 1). It was compared to consecutive data for all patients ≥80 years (group 2). Data were collected for patient demographics, stone characteristics, operative details, and clinical outcomes.

RESULTS

A total of 168 patients had 201 URSL procedures during this time (74 and 94 patients in groups 1 and 2 respectively). The mean age and stone sizes were 6.1 years and 85 years, and 9.7 mm and 13 mm for groups 1 and 2 respectively. While the SFR was slightly higher in group 2 (92.5% versus 87.8%, p = 0.301), post-operative stent rate was also significantly higher in the geriatric population (75.9% versus 41.2%, p = 0.0001). There was also no significant difference in pre-operative stenting (p = 0.886), ureteric access sheath use (UAS) (p = 0.220) and post-operative complications. Group 1 had an intervention rate of 1.3/patient as compared to 1.1/patient in group 2. The overall complications were 7.2% and 15.3% in groups 1 and 2 respectively (0.069), with 1 Clavien IV complication related to post-operative sepsis and brief ICU admission in group 2.

CONCLUSION

The paediatric population had a marginally higher incidence of repeat procedure, but the overall SFR and complications were similar, and post-operative stent insertion rates were much better compared to geriatric patients. URSL is a safe procedure in the extremes of age groups with no difference in the overall outcomes between the two groups.

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.

Best Practice in Interventional Management of Urolithiasis: An Update from the European Association of Urology Guidelines Panel for Urolithiasis 2022

PURPOSE

The European Association of Urology (EAU) has updated its guidelines on clinical best practice in urolithiasis for 2021. We therefore aimed to present a summary of best clinical practice in surgical intervention for patients with upper tract urolithiasis.

MATERIALS AND METHODS

The panel performed a comprehensive literature review of novel data up to May 2021. The guidelines were updated and a strength rating was given for each recommendation, graded using the modified Grading of Recommendations, Assessment, Development, and Evaluations methodology.

RESULTS

The choice of surgical intervention depends on stone characteristics, patient anatomy, comorbidities, and choice. For shockwave lithotripsy (SWL), the optimal shock frequency is 1.0-1.5 Hz. For ureteroscopy (URS), a postoperative stent is not needed in uncomplicated cases. Flexible URS is an alternative if percutaneous nephrolithotomy (PCNL) or SWL is contraindicated, even for stones >2 cm. For PCNL, prone and supine approaches are equally safe. For uncomplicated PCNL cases, a nephrostomy tube after PCNL is not necessary. Radiation exposure for endourological procedures should follow the as low as reasonably achievable principles.

CONCLUSIONS

This is a summary of the EAU urolithiasis guidelines on best clinical practice in interventional management of urolithiasis. The full guideline is available at https://uroweb.org/guidelines/urolithiasis.

PATIENT SUMMARY

The European Association of Urology has produced guidelines on the best management of kidney stones, which are summarised in this paper. Kidney stone disease is a common condition; computed tomography (CT) is increasingly used to diagnose it. The guidelines aim to decrease radiation exposure to patients by minimising the use of x-rays and CT scans. We detail specific advice around the common operations for kidney stones.

Single-Session Impact of High-Power Laser with Moses Technology for Lower Pole Stones in Retrograde Intrarenal Surgery: Retrospective Study

Background: This study aimed to evaluate the efficacy of a high-power holmium laser with Moses technology (MT) for the treatment of lower pole stones during retrograde intrarenal surgery (RIRS). Methods: Herein, 305 patients with lower pole stones who underwent RIRS using a high-power holmium laser with MT were retrospectively classified into the stone-free (SF) and non-SF groups. We measured the stone burden, stone volume, stone hardness, pre- or post-operative stent placement, infundibulopelvic angle (IPA), infundibular width (IW), infundibular length (IL), and calyceal pelvic height in terms of pelvicalyceal anatomy using retrograde pyelograms and evaluated the predictive factors of postoperative SF. Results: A total of 173 (56.7%) and 229 (75.1%) patients achieved a SF status on postoperative day one and at one month, respectively. Operation time in the SF group was shorter than that in the non-SF group (51.0 vs. 74.5 min). There were no significant differences in postoperative complications between the SF and non-SF groups. Significantly predictive risk factors in postoperative SF included total stone volume (odds ratio (OR), 1.056; 95% CI, 1.015-1.099; p = 0.007), IPA (OR, 0.970; 95% CI, 0.956-0.993; p = 0.009), and IW (OR, 0.295; 95% CI, 0.121-0.718; p = 0.007). The cut-off values of stone volume, IPA, and IW were 515.2 mm³, 46.8°, and 7.75 mm, respectively. Conclusions: A high-power holmium laser with MT in lower pole stones is a valuable option for positive outcomes and patient's safety. Larger stone volume, acute IPA, and narrow IW were negative predictors related to postoperative SF status.

A High-Fidelity Artificial Urological System for the Quantitative Assessment of Endoscopic Skills

Minimally-invasive surgery is rapidly growing and has become a standard approach for many operations. However, it requires intensive practice to achieve competency. The current training often relies on animal organ models or physical organ phantoms, which do not offer realistic surgical scenes or useful real-time feedback for surgeons to improve their skills. Furthermore, the objective quantitative assessment of endoscopic skills is also lacking. Here, we report a high-fidelity artificial urological system that allows realistic simulation of endourological procedures and offers a quantitative assessment of the surgical performance. The physical organ model was fabricated by 3D printing and two-step polymer molding with the use of human CT data. The system resembles the human upper urinary tract with a high-resolution anatomical shape and vascular patterns. During surgical simulation, endoscopic videos are acquired and analyzed to quantitatively evaluate performance skills by a customized computer algorithm. Experimental results show significant differences in the performance between professional surgeons and trainees. The surgical simulator offers a unique chance to train endourological procedures in a realistic and safe environment, and it may also lead to a quantitative standard to evaluate endoscopic skills.

Retrograde Intrarenal Surgery in Children: Evolution, Current Status, and Future Trends

Introduction: Incidence of urolithiasis in children has increased in recent years and with technological advancements and miniaturization of surgical instruments, pediatric urologists have acquired an impressive arsenal for their treatment. Retrograde intrarenal surgery (RIRS) has gained widespread popularity as it is a natural extension of semirigid ureteroscopy and can be done through natural orifice minimizing the morbidity of percutaneous access. The aim of this narrative review is to describe how RIRS has evolved over the decades in children and if the age-related anatomical difference impacts reported outcomes especially stone-free rate (SFR) and complications. Materials and Methods: An electronic literature search from inception to October 15, 2021 was performed using Medical Subject Heading terms in several combinations on PubMed, EMBASE, and Web of Science without language restrictions. A total of 2022 articles were founded and 165 articles were full-text screening. Finally, 2 pediatric urologists included 51 articles that summarize the available literature regarding the development and use of RIRS in children. Results: RIRS as of today is well established as a superior modality for all stones in all locations compared with extracorporeal shockwave lithotripsy both in children and adults. The passive dilation has decreased the need of active ureteral dilation, but the need to perform prestenting is not defined yet. Regarding the use of the ureteral access sheath, the literature tends to lean toward its placement in most cases, but we do not know its long-term effects over the growth of children. Finally, the SFR has increased as the experience of pediatric urologists increases, as well as the number of complications has decreased. Conclusion: RIRS in pediatrics has crossed many milestones, yet many areas need further research and larger data are required to make RIRS the procedure of choice for renal stone management in children across all age groups.

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

BACKGROUND

Retrograde intrarenal surgery (RIRS) has become the preferred treatment modality for nephrolithiasis. However, because of ongoing uncertainties regarding the optimal perioperative management, operative technique, and postoperative follow-up, as well as a lack of standardization for outcome reporting, consensus is needed to achieve more uniform clinical practice worldwide.

OBJECTIVE

To develop recommendations for RIRS on the basis of existing data and expert consensus.

DESIGN, SETTING, AND PARTICIPANTS

A protocol-driven, three-phase study was conducted by the European Association of Urology Section of Urolithiasis (EULIS) and the International Alliance of Urolithiasis (IAU). The process included: (1) a nonsystematic review of the literature to define domains for discussion; (2) a two-round modified Delphi survey involving experts in this field; and (3) an additional group meeting and third-round survey involving 64 senior representative members to formulate the final conclusions.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The results from each previous round were returned to the participants for re-evaluation of their decisions during the next round. The agreement threshold was set at 70%.

RESULTS AND LIMITATIONS

The panel included 209 participants who developed 29 consensus statements on the following topics of interest: (1) perioperative infection management; (2) perioperative antithrombotic therapy; (3) fundamentals of the operative technique; and (4) standardized outcome reporting. Although this consensus can be considered as a useful reference for more clinically oriented daily practice, we also acknowledge that a higher level of evidence from further clinical trials is needed.

CONCLUSIONS

The consensus statements aim to guide and standardize clinical practice and research on RIRS and to recommend standardized outcome reporting.

PATIENT SUMMARY

An international consensus on the best practice for minimally invasive surgery for kidney stones was organized and developed by two international societies. It is anticipated that this consensus will provide further guidance to urologists and may help to improve clinical outcomes for patients.

Radiomics in Urolithiasis: Systematic Review of Current Applications, Limitations, and Future Directions

Radiomics is increasingly applied to the diagnosis, management, and outcome prediction of various urological conditions. Urolithiasis is a common benign condition with a high incidence and recurrence rate. The purpose of this scoping review is to evaluate the current evidence of the application of radiomics in urolithiasis, especially its utility in diagnostics and therapeutics. An electronic literature search on radiomics in the setting of urolithiasis was conducted on PubMed, EMBASE, and Scopus from inception to 21 March 2022. A total of 7 studies were included. Radiomics has been successfully applied in the field of urolithiasis to differentiate phleboliths from calculi and classify stone types and composition pre-operatively. More importantly, it has also been utilized to predict outcomes and complications after endourological procedures. Although radiomics in urolithiasis is still in its infancy, it has the potential for large-scale implementation. Its greatest potential lies in the correlation with conventional established diagnostic and therapeutic factors.

Hybrid flexible ureteroscopy strategy in the management of renal stones - a narrative review

The introduction of single-use flexible ureteroscopes (suFURSs) in daily practice tends to overcome the main limitations of reusable ureteroscopes (reFURSs), in terms of high acquisition costs, maintenance, breakages and repairing costs, reprocessing and sterilization, as retrograde intrarenal surgery (RIRS) is promoted as first-line treatment of renal stones in most cases. A hybrid strategy implies having both instruments in the armamentarium of endourology and choosing the best strategy for cost-efficiency and protecting expensive reusable instruments in selected high-risk for breakage cases such as large stones of the inferior calyx, a steep infundibulopelvic angle or narrow infundibulum, or abnormal anatomy as in horseshoe and ectopic kidney. In terms of safety and efficiency, data present suFURSs as a safe alternative considering operating time, stone-free, and complication rates. An important aspect is highlighted by several authors about reusable instrument disinfection as various pathogens are still detected after proper sterilization. This comprehensive narrative review aims to analyze available data comparing suFURSs and reFURSs, considering economic, technical, and operative aspects of the two types of instruments, as well as the strategy of adopting a hybrid approach to selecting the most appropriate flexible ureteroscope in each case.

Comparison of the Efficacy and Complications of Soft Ureteroscopy Lithotripsy and Percutaneous Nephrolithotomy in the Treatment of Urinary Calculi: A Systematic Review and Meta-analysis

Objective

To systematically evaluate the efficacy and complications of soft ureteroscopic lithotripsy (SUL) and percutaneous nephrolithotomy (PCNL) in the treatment of urinary calculi and to provide evidence-proof medicine basis for the popularization and application of flexible ureteroscopic lithotripsy.

Methods

PubMed, EMBASE, ScienceDirect, Cochrane Library, China knowledge Network Database (CNKI), China VIP Database, Wanfang Database, and China Biomedical Literature Database (CBM) were searched for randomized controlled trials (RCT) related to soft ureteroscopic lithotripsy and percutaneous nephrolithotomy in the treatment of urinary calculi from Jan. 2010 to Mar. 2022. The bias risk of each included literature was assessed according to the standard of Cochrane manual 5.1.0. The collected data were meta-analyzed by RevMan 5.4 statistical software.

Results

Ultimately, 6 RCT (a total of 794 samples) were included for meta-analysis. Heterogeneity test results of stone clearance rate were chi² = 2.44, df = 5, P = 0.79 > 0.05, and I² = 0%, indicating none obvious heterogeneity among the included research data. The test of WMD was Z = 2.11 (P = 0.03). It could be considered that compared with PCNL in the treatment of urinary calculi, SUL had a higher stone clearance rate in patients with urolithiasis. Secondly, heterogeneity test of operation time was chi² = 184.95, df = 5, P < 0.00001, and I² = 97%. The results of heterogeneity test of intraoperative blood loss displayed chi² = 645.47, df = 5, P < 0.00001, and I² = 99%. Then, heterogeneity test results of postoperative hospital stay existed chi² = 57.37, df = 5, P < 0.00001, and I² = 91% with an obvious heterogeneity. According to the results of this analysis, it could be considered that compared with PCNL in the treatment of urolithiasis, the operation time of SUL in the treatment of urolithiasis was longer, but the amount of intraoperative bleeding and postoperative hospital stay was significantly reduced. The results of heterogeneity of stress index level NE showed as chi² = 0.32, df = 2, P = 0.85 > 0.05, and I² = 0%, and COR was chi² = 1.09, df = 1, P = 0.30 > 0.05, and I² = 8%. It showed that there was no obvious heterogeneity. The heterogeneity of ACTH was chi² = 390.36, df = 2, P < 0.00001, and I² = 99%, suggesting obvious heterogeneity. The test of combined effect dose WMD was Z = 21.90, 4.50, and 15.42, (P < 0.00001). It could be considered that there was a statistical difference in the WMD of stress response between patients with urinary calculi treated by soft ureteroscope and percutaneous nephrolithotomy, indicating that the stress response of patients with urinary calculi treated with SUL is less than that of PCNL. For the heterogeneity test of serum creatinine level, NE showed chi² = 0.78, df = 2, P = 0.68 > 0.05, and I² = 0% without obvious heterogeneity, and the combined effect dose WMD is analyzed by random effect model. The test of combined effect dose WMD was Z = 4.22 (P < 0.00001). It can be considered that the improvement of serum creatinine level in patients with urolithiasis treated with SUL was better than that of PCNL. The results of heterogeneity test on the safety of operation are as follows: chi² = 13.76, df = 5, P = 0.02, and I² = 64%, indicating obvious heterogeneity among the included research data. The combined effect dose of WMD was Z = 5.53 (P < 0.00001). This could be considered that soft ureteroscopic lithotripsy had higher safety and less postoperative complications than percutaneous nephrolithotomy in the treatment of urinary calculi. An inverted funnel chart was used to analyze the publication bias of the study with stone clearance rate as the outcome index. The results showed that the figure was not completely symmetrical and the Egger's test showed that the figure was P = 0.0005 < 0.001. It was suggested that there may be a certain degree of publication bias.

Conclusion

PCNL and SUL can achieve higher stone clearance rate in the treatment of renal calculi. However, SUL has the advantages of less intraoperative bleeding, short stress reaction and postoperative hospital stay, less damage to renal function, and low incidence of complications, which is beneficial to the rapid recovery of patients after operation. More studies with higher methodological quality and longer intervention time are needed to further verify.

The effects of stone density on surgical outcomes of retrograde intrarenal stone surgery

OBJECTIVE

Several pre-operative parameters have been studied to estimate stone-free rate (SFR) following retrograde intrarenal surgery (RIRS) procedures. The objective of this study was to evaluate the effects of stone density on surgical outcomes of RIRS.

METHODS

This retrospective study included 30 stone-free patients (Group SF) and 30 patients with residual fragments (Group RF). Patients' age and gender, laterality, non-contrast CT findings, including size and density of the kidney stones, infundibular pelvic angle (IPA), operational time, and post-operative pain were recorded and compared between the two groups. The stone density was measured by free hand region of interest (ROI) determination coincident with the stone borders and expressed as Hounsfield units (HUs).

RESULTS

The rate of single stones was significantly higher in Group SF compared to Group RF (p < 0.001). The mean stone size was found as 11.93 ± 7.81 mm in Group SF and 16.27 ± 7.29 mm in Group RF with the difference being statistically significant (p < 0.001). The mean IPA was 53.87 degrees in Group SF and 50.33 degrees in Group RF. The mean density was measured as 748.17 ± 318.14 HU in Group SF and 945.90 ± 345.30 HU in Group RF. The mean stone density was statistically significantly higher in patients with residual fragments compared to the stone-free patients (p < 0.001).

CONCLUSION

This study revealed that stone density as measured as HU affects the treatment outcomes with RIRS procedure and the mean density is significantly higher in patients with residual stone fragments.

ADVANCES IN KNOWLEDGE

Studies about the effects of HUs on stone-free rate are limited in the literature. Stone density affects the treatment outcomes with RIRS procedure and the mean density is significantly higher in patients with residual stone fragments.

The dilemma of 12/14F ureteral access sheath (UAS) usage: a case control study

BACKGROUND

The insertion of a ureteral access sheath (UAS) is a frequent procedure during flexible ureteroscopy (fURS) to facilitate kidney stone treatment. The aim of this study was to investigate the influence of 12/14 French (F) UAS on fURS outcomes.

METHODS

We performed a retrospective monocentric analysis of fURS procedures conducted at the Department of Urology (University Hospital Schleswig-Holstein, Lübeck, Germany) for kidney stone treatment via lithotripsy or basket stone retrieval between September 2013 and June 2017. Uni- and multivariate analyses were done with the help of RStudio (Version 1.0.136) software.

RESULTS

In total, 283 consecutive fURS were analyzed. UAS was applied in 98 cases (34.63%). The insertion of UAS was preferred in cases with multiple kidney stones and larger median maximal stone diameter (p < 0.05). UAS usage correlated with elevated radiation exposure in seconds (94 vs. 61; p < 0.0001), prolonged operation time in minutes (99 vs. 66, p < 0.0001), length of hospital stay over 48 h (LOS, 22.49% vs. 10.81%; p = 0.015), more frequent postoperative systemic inflammatory response syndrome (SIRS, 13.27% vs. 4.32%; p = 0.013) and lower postoperative stone-free rates (60.20% vs. 78.92%; p = 0.0013). Moreover, we conducted uni- and multivariate subgroup analysis for cases with multiple kidney stones (≥ 2) and comparable stone burden; UAS was inserted in 48.3% of these cases (71/147). On multivariate logistic regression, UAS insertion was statistically associated with prolonged operation time in minutes (101 vs. 77; p = 0.004). No statistical differences regarding radiation exposure, stone-free rates, postoperative SIRS rates or LOS were noted between UAS and non-UAS patients with multiple kidney stones of similar size (p > 0.05).

CONCLUSIONS

12/14F UAS does not seem to improve overall outcomes in fURS for kidney stones. In patients with multiple kidney stones it may be associated with elevated operation time without a clear benefit in terms of improved stone-free status or reduced perioperative complication rate. Further prospective randomized studies to specify the indications for UAS usage are urgently needed.

Development of a novel predictive model for a successful stone removal after flexible ureteroscopic lithotripsy based on ipsilateral renal function: a single-centre, retrospective cohort study in China

OBJECTIVES

The aims of this study were to investigate the effect of preoperative ipsilateral renal function on the success of kidney stone removal with flexible ureteroscopic lithotripsy and to develop a predictive model based on the results.

DESIGN

Retrospective cohort study.

SETTING

Data from the 2001-2012 period were collected from the electronic records of West China Hospital, Sichuan University.

PARTICIPANTS

576 patients who underwent flexible ureteroscopic lithotripsy were included in the study.

PRIMARY OUTCOME

Stone-free rate (SFR) after the procedures.

RESULTS

In patients with suspected impaired kidney function, the overall SFR was 70.1%. Stone volume (OR 1.46; 95% CI 1.18 to 1.80), lower calyx stones (OR 1.80; 95% CI 1.22 to 2.65), age (OR 1.02; 95% CI 1.00 to 1.04), body mass index (OR 1.10; 95% CI 1.04 to 1.17) and estimated glomerular filtration rate of the affected kidney (OR 0.95; 95% CI 0.94 to 0.97) were identified as independent predictors of SFR. Lasso regression selected the same five predictors as those identified by univariate and multivariate logistic regression analyses, thus verifying our model. The mean area under the curve, based on 1000 iterations and 10-fold validation, was 0.715 (95% CI 0.714 to 0.716). The Hodges-Lehmann test and calibration curve analysis revealed no significant mismatch between the prediction model and the retrospective cohort.

CONCLUSION

Ipsilateral renal function may be a novel independent risk factor for kidney stone removal with flexible ureteroscopic lithotripsy. A novel nomogram for predicting SFR that uses stone volume, lower calyx stones, age, body mass index and estimated glomerular filtration rate was developed, but remains to be externally validated.

Role of low- versus high-power laser in the treatment of lower pole stones: prospective non-randomized outcomes from a university teaching hospital

Introduction:

Ureteroscopy and laser stone fragmentation [flexible ureteroscopy and laser lithotripsy (FURSL)] has risen over the last two decades. Laser technology has also evolved over the time, shifting from low- to high-power lasers with the addition of MOSES technology that allows for ‘dusting and pop-dusting’ of stones. The aim of the study was to look at the outcomes of FURSL in lower pole stones (LPS) using low- and high-power lasers.

Patient and Methods:

In this study, we compared the outcomes of low-power holmium laser (group A, 20 W) and high-power holmium laser (group B, including both 60 W MOSES integrated system and 100 W lasers) for all patients with LPS treated with laser lithotripsy. Data were collected for patient demographics, stone location, size, pre- and postoperative stent, length of stay, complications and stone free rate (SFR).

Results:

A total of 284 patients who underwent FURSL procedure for LPS were analysed (168 group A, 116 group B). Outcomes showed that compared with group A, group B had a higher SFR (91.6% versus 96.5%, p = 0.13) and shorter operative time (52 versus 38 min, p < 0.001). The median length of stay was <24 h in all groups (day-case procedures). The complication rate was comparable between the two groups but with more infectious complications (n = 7) noted in group A compared with group B (n = 3) (p = 0.53).

Conclusion:

Compared with low-power laser, the use of high-power laser for LPS significantly reduced the use of ureteral access sheath (UAS), postoperative stent and procedural time. Although non-statistically significant, the SFR was higher in the high-power group even for relatively larger stone sizes, which was also reflected in a reduction of sepsis-related complication rates with these lasers.

Needle-perc-assisted endoscopic surgery for patients with complex renal stones: technique and outcomes

Our aim was to investigate the safety and efficacy of needle-perc-assisted percutaneous nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS), namely, needle-perc-assisted endoscopic surgery (NAES), in a series of patients with large and/or complex renal stones. From May 2018 to August 2021, a total of 119 patients underwent NAES at our institute. Among them, 94 patients underwent needle-perc-assisted standard PCNL in prone position and 25 underwent needle-perc-assisted RIRS in the Galdakao-modified supine Valdivia position or prone split-leg position. Clinical factors including age, sex, medical history, and stone characteristics were collected. Intraoperative and postoperative outcomes were retrospectively evaluated. The patients' mean age ± standard deviation was 50.3 ± 14.3 years. The mean stone size was 7.6 ± 3.7 and 1.7 ± 0.8 cm for needle-perc-assisted PCNL and RIRS, respectively. Of the 119 patients, 51 had staghorn stones, 16 had solitary kidneys, 17 had a history of ipsilateral renal surgery, and 6 had calyceal diverticular stones. The mean operative time was 83.4 ± 25.9 min for needle-perc-assisted PCNL and 66.3 ± 21.8 min for needle-perc-assisted RIRS. The stone-free rate (SFR) for needle-perc-assisted PCNL was 77.7% after the first treatment and 88.3% after auxiliary treatments. The SFR for needle-perc-assisted RIRS was 88.0% and no auxiliary treatments were carried out in this group. Eleven (11.7%) patients who underwent needle-perc-assisted standard PCNL developed Clavien-Dindo grade I or II complications. Three (12.0%) patients who underwent needle-perc-assisted RIRS developed a fever (grade I). The overall complication rate for NAES was 11.8%, with no urosepsis, angioembolization, or other grade III to V complications. In conclusion, NAES is a safe and effective procedure for one-step complete resolution of large and/or complex renal stones with no additional procedure-related complications.

Retrograde intrarenal surgery in lateral position for lower pole stone: an initial experience from Single Academic Hospital

Retrograde intrarenal surgery (RIRS) was generally challenging in management of lower pole stone (LPS) since the unfavorable anatomy. Theoretically, LPS was prone to fall out and down to renal pelvis when patients turned to lateral position, thus to facilitate lithotripsy. The aim of the present study was to report our initial experience of RIRS in lateral position for LPS. From January 2020 to February 2021, 21 patients with LPS received RIRS in lateral position. The intraoperative finding, operation time, complications and stone-free rate (SFR) were recorded and analyzed. The mean stone size was 16.7 ± 2.4 mm, multiple stones in lower pole were noted in 38.1% (8/21) cases. The mean infundibular-pelvic angle (IPA) was 35.2 ± 6.9°, IPA less than 30° was noted in six cases (28.6%, 6/21). Mean operation time was 43.5 ± 6.3 min. Obvious stone fragments dropping from the lower calyx to renal pelvis during the lithotripsy were noted in 17 cases (81.0%). Only one case (4.8%) suffered postoperative fever (Clavien I), no severe complication (> Clavien II) was noted. Hospital stay was 1.1 ± 0.3 days, the SFR in postoperative 1 month was 85.7%. LPS was prone to fall out and down to renal pelvis when patients in lateral position, thus to facilitate the lithotripsy. RIRS in lateral position was feasible for the management of LPS; however, RCT with large sample was required to certify our initial finding.

Retrograde Intrarenal Surgery Versus Miniaturized Percutaneous Nephrolithotomy for Kidney Stones >1cm: A Systematic Review and Meta-analysis of Randomized Trials

CONTEXT

Although miniaturized percutaneous nephrolithotomy (mPCNL) and retrograde intrarenal surgery (RIRS) are both options for treating >1cm kidney stones, controversies exist on whether one is more effective and safer than the other.

OBJECTIVE

To systematically appraise randomized trials comparing the effectiveness and safety of mPCNL and RIRS for treating >1cm kidney stones.

EVIDENCE ACQUISITION

A systematic search on PubMed/Medline, Web of Science, Embase, and ClinicalTrials.gov was conducted in August 2020 following the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA). Randomized trials comparing mPCNL and RIRS for >1cm kidney stones, and reporting stone-free rate (SFR), hemoglobin drop, transfusion rate, length of hospital stay (LOS), and/or complications, were included.

EVIDENCE SYNTHESIS

Eight studies compared mPCNL and RIRS, but one was not included due to its high risk of bias. SFR was higher for mPCNL (RR: 1.06 [95% coefficient interval {CI}, 1.01-1.10], p=0.008). Hemoglobin drop was higher for mPCNL (mean difference [MD]: 0.35 [95% CI, 0.05-0.65] g/dl, p=0.02); however, transfusion rates were similar (p=0.44). Complication rate was similar between mPCNL and RIRS (p=0.39), and the LOS was higher for mPCNL (MD: 1.11 [95% CI, 0.06-2.16] d, p=0.04). A subgroup analysis of lower pole stones showed that SFR was higher for mPCNL (RR: 1.09 [95% CI, 1.00-1.19], p=0.05).

CONCLUSIONS

Both approaches are effective and safe. Among these approaches, mPCNL has a higher SFR than RIRS for overall >1cm renal and lower pole stones, but longer LOS, and a higher hemoglobin drop that does not translate into higher transfusion rates. Complications are comparable.

PATIENT SUMMARY

Randomized trials have evaluated whether miniaturized percutaneous nephrolithotomy (mPCNL) or retrograde intrarenal surgery is more effective and safer for treating >1cm stones. After comparing the stone-free rate, hemoglobin drop, transfusion rate, length of hospital stay, and complications between both the approaches, mPCNL was found to be slightly more effective, but both were equally safe.

Comparison of two techniques for the management of 2-3 cm lower pole renal calculi in obese patients

OBJECTIVE

To compare the outcomes of mini percutaneous nephrolithotomy (mPNL) and retrograde intrarenal surgery (RIRS) for the management of 2-3 cm lower pole renal calculi (LPC) in obese patients.

PATIENTS AND METHODS

120 obese patients with 2-3 cm LPC were randomly divided into mPNL group and RIRS group. Demography, clinical characteristics, perioperative complications, and stone free rate (SFR) were recorded. Stone-free status means no stone on computed tomography 3 months after surgery, or residual fragments were less than 3 mm.

RESULTS

Baseline characteristics were similar between the two groups. The mean stone burden was 585.39 ± 131.06 mm² in the mPNL group and 548.64 ± 123.55 mm² in the RIRS group (P = 0.125). The SFR of mPNL group was significantly better than that of RIRS group (86.2% vs 61.4%, P = 0.002). Besides, the overall complication rate was 22.4% in the mPNL group and 7% in the RIRS group (P = 0.02). Patients performed with mPNL required longer length of hospital stay than those with RIRS (P = 0.001). There were no significant differences in operative time and stone composition between the two groups.

CONCLUSION

In our study, both mPNL and RIRS are safe and effective techniques for the treatment of 2-3 cm LPC in obese patients. Compared to RIRS, mPNL has better SFR at the expense of the higher incidence of complications and prolonged length of hospital stay.

Efficiency of retrograde intrarenal surgery in lower pole stones: disposable flexible ureterorenoscope or reusable flexible ureterorenoscope?

PURPOSE

The primary aim of this study to comparison of reusable and disposable flexible ureterorenoscope (fURS) efficiency in lower pole renal stone disease management. In addition, the secondary goal of this study was to evaluate the factors affecting stone-free rates (SFR) in lower pole stones.

MATERIALS AND METHODS

A prospective case-control study utilizing data from 122 consecutive ureteroscopic cases. The patients were divided into two groups according to the ureterorenoscope employed in the surgical intervention as disposable fURS (Group1, n:52) and reusable fURS (Group 2, n:70). Demographic characteristics, stone size, infundibulopelvic angle (IPA), SFR, hospitalization time, intraoperative complication rate (CR), operative time, preoperative or postoperative JJ stenting, and postoperative CR were analyzed.

RESULTS

There was no statistical difference between the demographic and renal stone-related data between the groups. Likewise, no difference is observed in term of intraoperative and postoperative outcomes such as fluoroscopy time, CR, and hospitalization time between the groups. Although SFR was higher in the disposable fURS group, there was no difference statistically. However, the operative time was longer in reusable fURS Group (47.02 ± 9.91 min in Group 1, and it was 57.97 ± 14.28 in Group 2) (p: 0.001). The multivariate regression analysis result to evaluate the factors of effect to operative time; the use of disposable fURS was associated with a 10.95-min decrease in procedure duration (p < 0.001).

CONCLUSIONS

Disposable fURS and reusable fURS have similar clinical efficiency and complication rates in the treatment of lower calyceal stones with RIRS. Nevertheless, disposable fURS is a useful treatment option for increased stone volume due to the advantages such as shorter operative time.

Modified Takazawa anatomical classification of renal pelvicalyceal system based on three-dimensional virtual reconstruction models

Background

Previous classification of renal pelvicalyceal anatomical structure may be difficult to intuitively understand and unpractical for endourological surgery. We aim to put forward a modified Takazawa anatomical classification of renal pelvicalyceal system based on three-dimensional (3D) virtual reconstruction models for endourological surgery.

Methods

We retrospectively collected data on 225 patients (320 kidneys) in total between Apr. 2017 and Dec. 2020, spatial anatomical structure of renal pelvis and calyces were modeled and corresponding morphological parameters were measured after 3D virtual reconstruction of computed tomography urography (CTU). The modified Takazawa renal pelvicalyceal anatomical classification was advanced based on the renal pelvicalyceal morphological parameters [bifurcated branches of renal pelvis, cross sectional area of renal pelvis and ureteropelvic junction (UPJ), infundibuloureteral angle (IUA), lower pole infundibular calyceal length (IL)] by 3D virtual reconstruction models, and comparison of renal pelvicalyceal system morphological parameters were performed to evaluate the differences in various classification types of renal pelvis and calyces.

Results

Anatomical structure of renal pelvis and calyces were divided into two main types (Type A and Type B) according to renal pelvic branch patterns. A single pelvis without bifurcated branch was regarded as Type A (62%) and subclassified into three subtypes: Type A1 (22%), Type A2 (27%) and Type A3 (13%), the slimline pelvis was classified as Type A1, the typical pelvis as Type A2 and the broad pelvis as Type A3. A divided pelvis with bifurcated branches was seen as Type B (38%) and subclassified into two subtypes: Type B1 (15%) with the wide and flat lower calyx branch, Type B2 (23%) with the narrow and steep lower calyx branch.

Conclusions

Previous studies have reported that the visualization and classification of renal pelvicalyceal anatomical structure by endocast, autopsy, ultrasonography and excretory urography, the modified Takazawa classification system based on 3D virtual reconstruction models enables to standardized different anatomical morphology of renal pelvicalyceal system and provide intuitive and concise information on anatomy, thus leading to the improvement in treatment modality.

Laparoscopic ureterolithotomy and retrograde flexible ureteroscopy-assisted transperitoneal laparoscopic ureteroureterostomy for a huge ureteropelvic junction stone and multiple small renal stones: A CARE-compliant case report

RATIONALE

Concurrent kidney and ureteral stones are always complicated and a clinical challenge. Improvements in endoscopic equipment have led to the widespread adoption of retrograde intrarenal surgery, which has a good stone clearance rate. On the other hand, laparoscopic ureterolithotomy (LUL) has been reported to be non-inferior to retrograde flexible ureteroscopy in stone-free rate and the need for axillary procedures, and to have a significantly lower rate of post-operative sepsis compared to retrograde flexible ureteroscopy. We describe a case managed with LUL followed by laparoscope-assisted retrograde intrarenal surgery (LA-RIRS) in a single operation for a large upper ureteral stone and small renal stones, which is usually challenging and requires axillary procedures.

PATIENT CONCERNS

The patient was a 66-year-old male with underlying hypertension and diabetes mellitus. He reported severe flank pain after receiving endoscopic management of concurrent right ureteropelvic junction stone and multiple renal stones about 1 month previously.

DIAGNOSIS

The residual stones were reassessed using non-contrast computed tomography before surgery. A 2.8-cm residual ureteropelvic junction stone and multiple renal stones with a maximum length of 1 cm were found. A second operation was considered to be necessary due to the deterioration of his renal function and refractory flank pain.

INTERVENTIONS

We performed LUL followed by LA-RIRS. Two surgeries were completed in a single operation. The Jackson-Pratt drain was removed 3 days after the operation.

OUTCOMES

After the surgery, no high-grade complications were recorded according to the Clavien Dindo classification. A follow-up kidney, ureter, and bladder radiograph performed 2 months after the operation revealed no residual stones. Renal echo revealed no obstructive nephropathy 1 month after double-J catheter removal.

CONCLUSION

LUL with LA-RIRS with a stone basket for renal stone extraction is a safe and feasible technique, and no step surgery or axillary procedures were needed in our case. If clinical cases with a huge stone burden over the ureter are indicated for LUL with concurrent small renal stones, LUL with LA-RIRS can be an alternative option.

Evaluation of the anatomical factors affecting the success of retrograde intrarenal surgery for isolated lower pole kidney stones

Studies which examine the factors affecting success rate in kidney stones located in the lower pole as well as the effects of infundibulopelvic angle (IPA) and infundibular length (IL) have been conducted with a small number of patients. We aimed to evaluate the cut-off points of IPA and IL parameters that effect the success of retrograde intrarenal surgery (RIRS) for isolated lower pole kidney stones. This retrospective study includes 168 patients who underwent primary RIRS due to isolated lower pole kidney stones in our clinic between January 2013 and May 2020. Pre-operative demographic data, medical history, physical examination, surgery duration as well as the post-operative hospitalization time of patients specifics were obtained. According to pre-operative computed tomography (CT), stone size, stone burden, stone density, number of stones (single and multiple), stone laterality, congenital kidney abnormality, the presence of solitary kidney, parameters of IPA and IL were measured and both included in the study. All patients were divided into two groups as the successful group and the unsuccessful group according to their post-operative success. These two groups were compared in terms of pre and post-operative data. Stone burden, IPA < 42.65°, and IL > 27.5 mm were specified as the independent risk factors for success of RIRS procedure. The patients for whom RIRS procedure is planned for lower pole kidney stones, stone burden, IPA, and IL should be taken into consideration to be able to predict success and it should be kept in mind that additional treatment may be required.

Is flexible ureteroscopy and laser lithotripsy (FURSL) the new gold standard for paediatric lower pole stones: Outcomes from 2 large European tertiary paediatric endourology centres

INTRODUCTION

While paediatric ureteroscopy has been increasingly performed, the evidence for its use in paediatric lower pole stones (LPS) is sparce. In this study we look at the effectiveness and outcomes of flexible ureteroscopy and lasertripsy (FURSL) in the management of LPS for a paediatric population.

METHODS

Data were collected from two large European tertiary endourology centres which specialise in paediatric kidney stone management. The study was registered as an audit at the respective hospitals. All data were cross-checked and analysed using electronic operative notes, discharge records, laboratory systems and patient correspondence. The inclusion criteria were patients 16 years with lower pole stones having a FURSL procedure.

RESULTS

A total of 57 paediatric patients underwent FURSL for LPS. The mean age was 10.1 years + 4.7 (range: 1-16.9 years) with a male:female ratio of 2:3. The mean single stone size was 9.45+3.9 mm (range: 3-20 mm) and 31(54.4%) had multiple stones. A pre-operative stent was present in 18(31.6%) patients and a post-operative stent or ureteric catheter was left behind in 32(56.1%) patients. The initial and final SFR was 82.4% and 98.2% respectively with 1.19 procedures per patient performed to be stone free. While there were no intra-operative complications, there were only four(7%) minor complications (Clavien I) noted which were all simple urinary infections. No long-term complications were noted.

CONCLUSION

Flexible ureteroscopy and lasertripsy achieves excellent outcomes for treatment of paediatric LPS. While some patients might need a second procedure for complete stone clearance, FURSL may be considered as the first-line treatment of lower pole stones.