Intraoperative and postoperative surgical complications after ureteroscopy, retrograde intrarenal surgery, and percutaneous nephrolithotomy: a systematic review

Effect of Using Automated Irrigation Systems on the Risk of Infectious Complications after Endoscopic Combined Intrarenal Surgery: A Retrospective Cohort Study

Objective: Endoscopic combined intrarenal surgery (ECIRS) is a treatment option for kidney stones comparable with other standard methods. One reported complication of ECIRS is infection associated with high intrarenal pressure (IRP), and the irrigation system is an important factor affecting the IRP. Therefore, this study aimed to compare the operative outcomes and infectious complications between manual and gravity irrigation and automated irrigation systems for ECIRS. Materials and Methods: This single-center, retrospective cohort study enrolled patients who underwent ECIRS between January 2016 and August 2021. We compared operative results and complications between the two irrigation systems, and a multivariate analysis was performed to identify the factors associated with each outcome. Results: A total of 294 patients were enrolled in this study. The operative time was significantly longer in the manual and gravity irrigation group than in the automated irrigation group (122 ± 45 vs 108 ± 37 minutes, p = 0.003). Postoperative fever occurred in 25% of the patients in the manual and gravity group compared with 10% in the automated group (p < 0.001). In multivariate analysis, the use of a manual and gravity irrigation system was a significant factor associated with postoperative fever (p = 0.001) and longer operative time (p < 0.001). Conclusions: Using an automated irrigation system for flexible ureteroscopy in ECIRS reduces the risk of postoperative fever and the operative time.

Predictors and associations of complications in ureteroscopy for stone disease using AI: outcomes from the FLEXOR registry

We aimed to develop machine learning(ML) algorithms to evaluate complications of flexible ureteroscopy and laser lithotripsy(fURSL), providing a valid predictive model. 15 ML algorithms were trained on a large number fURSL data from > 6500 patients from the international FLEXOR database. fURSL complications included pelvicalyceal system(PCS) bleeding, ureteric/PCS injury, fever and sepsis. Pre-treatment characteristics served as input for ML training and testing. Correlation and logistic regression analysis were carried out by a multi-task neural network, while explainable AI was used for the predictive model. ML algorithms performed excellently. For intraoperative PCS bleeding, Extra Tree Classifier achieved the best accuracy at 95.03% (precision 80.99%), and greatest correlation with stone diameter(0.21) and residual fragments(0.26). PCS injury was best predicted by RandomForest (accuracy 97.72%, precision 63.50%). XGBoost performed best for ureteric injury (accuracy 96.88%, precision 60.67%). Both demonstrated moderate correlation with preoperative characteristics. Postoperative fever was predicted by Extra Tree Classifier with 91.34% accuracy (precision 58.20%). Cat Boost Classifier predicted postoperative sepsis with 99.15% accuracy (precision 66.38%), and the best overall performance. At logistic regression, postoperative fever/sepsis positively correlated with preoperative urine culture(p = 0.001). ML represents a powerful tool for automatic prediction of outcomes. Our study showed promises in algorithms training and validation on a very large database of patients treated for urolithiasis, with excellent accuracy for prediction of complications. With further research, reliable predictive nomograms could be created based on ML analysis, to serve as aid to urologists and patients in the decision making and treatment planning process.

A novel predictive method for URS and laser lithotripsy using machine learning and explainable AI: results from the FLEXOR international database

PURPOSE

We developed Machine learning (ML) algorithms to predict ureteroscopy (URS) outcomes, offering insights into diagnosis and treatment planning, personalised care and improved clinical decision-making.

METHODS

FLEXOR is a large international multicentric database including 6669 patients treated with URS for urolithiasis from 2015 to 2023. Preoperative and postoperative(PO) correlations were investigated through 15 ML-trained algorithms. Outcomes included stone free status (SFS, at 3-month imaging follow up), intraoperative (PCS bleeding, ureteric/PCS injury, need for postoperative drainage) and PO complications (fever, sepsis, need for reintervention). ML was applied for the prediction, correlation and logistic regression analysis. Explainable AI emphasizes key features and their contributions to the output.

RESULTS

Extra Tree Classifier achieved the best accuracy (81%) in predicting SFS. PCS bleed was negatively linked with 'positive urine culture'(-0.08), 'tamsulosin'(-0.08), 'stone location'(-0.10), 'fibre optic scope'(-0.19), 'Moses Fibre'(-0.09), and 'TFL'(-0.09), and positively with 'elevated creatine'(0.25), 'fever'(0.11), and 'stone diameter'(0.21). 'PCS injury' and 'ureteric injury' both showed moderate correlation with 'elevated creatinine'(0.11), 'fever'(0.10), and 'lower pole stone'(0.09). 'Tamsulosin'(0.23) use, presence of 'multiple'(0.25) or 'lower pole'(0.25) stones, 'reusable scope'(0.17) and 'Moses Fibre'(0.2546) increased the risk for PO stent, while 'digital scope'(-0.13) or 'TFL'(-0.29) reduced it. 'Preoperative fever'(0.10), 'positive urine culture'(0.16), and 'stone diameter'(0.10) may play a role in 'PO fever' and 'sepsis'. SFS was mainly influenced by 'age'(0.12), 'preoperative fever'(0.09), 'multiple stones'(0.15), 'stone diameter'(0.17), 'Moses Fibre"(0.15) and 'TFL'(-0.28).

CONCLUSION

ML is valuable tool for accurately predicting outcomes by analysing pre-existing datasets. Our model demonstrated strong performance in outcomes and risks prediction, laying the groundwork for development of accessible predictive models.

Investigation of the predictive value of Hounsfield units in predicting stone culture results in urinary stone disease

This study aimed to investigate the predictive ability of Hounsfield unit (HU) measurements for microorganism growth observed microbiologically in stone cultures after stone surgery and to create a model by adding other predictive factors for predicting stone culture positivity. Patients who underwent percutaneous nephrolithotomy, retrograde intrarenal surgery, or ureteroscopy and had stone cultures performed were included in the study. Demographic and clinical data, including age, gender, body mass index, stone size, stone volume, hydronephrosis grade, stone location, energy used, presence of preoperative stent or nephrostomy, operation duration, midstream urine culture, renal pelvic urine culture, stone culture results, and postoperative fever and systemic inflammatory response syndrome criteria, were recorded. Non-contrast computed tomography images were used to measure the HU at the stone's core (HUcore), the proximal surface of the stone periphery in the collecting system (HUproximal), the distal surface of the stone periphery in the collecting system (HUdistal), and the average HU of the stone periphery (HUperiphery mean). Absolute and relative differences between these values were calculated. A total of 383 patients were included, with microorganism growth observed in the stone cultures of 75 patients (19.6%). Radiological cut-off values distinguishing stones with positive cultures included RelativeHUdifference distal & proximal < 81.8, HUproximal < 807.0, and AbsoluteHUdifference core & periphery mean > 179.5. Factors associated with a statistically significant increase in the likelihood of positive stone cultures included longer operation duration (odds ratio [OR] = 1.102, 95% confidence interval [CI]: 1.053-1.154, p < 0.001), higher preoperative hydronephrosis grade (OR = 1.898, 95% CI: 1.289-2.795, p < 0.001), and the presence of preoperative stents or nephrostomy (OR = 4.232, 95% CI: 1.551-11.543, p = 0.005) in addition to the identified radiological HU cut-off values. HU values, as a radiological parameter, can predict microorganism growth in stone cultures, enabling identification of patients at risk for postoperative infectious complications.

Comparison of clinical effectiveness and safety of 272 µm and 365 µm holmium lasers in retrograde intrarenal surgery

INTRODUCTION

Surgeons typically prefer 270 µm and 272 µm laser probes in retrograde intrarenal surgery (RIRS) due to the reduced deflection capacity of flexible ureterorenoscopes when using larger probe diameters. This study aims to investigate the effects of 272 and 365 µm holmium laser probes on operative time, clinical efficacy, and complication rates in RIRS.

MATERIALS AND METHODS

A total of 285 patients with proximal ureteral or kidney stones who met the inclusion criteria were enrolled in the study. Patients were divided into two groups based on laser probe thickness: 272 µm and 365 µm. Stone-free rates, operative time, and complication rates were compared between the groups. Factors affecting stone-free rates were analyzed using multivariate logistic regression analysis.

RESULTS

Patient and stone characteristics were similar between the two groups. No significant differences were found in stone-free or complication rates. However, operative time was significantly shorter in the 365 µm probe group. In univariate analysis, risk factors for postoperative residual stones included multi-calyceal stones, lower pole stones, high Hounsfield unit (HU) values on non-contrast computed tomography, and larger stone size. In multivariate analysis, independent prognostic factors for residual stones were identified as multi-calycal stones, lower pole stones, and high HU values.

CONCLUSION

Compared to 272 µm laser probes, operative time was shorter in surgeries performed with 365 µm laser probes. The 365 µm holmium laser can be effectively and safely used in the treatment of proximal ureteral and renal stones, demonstrating high clinical efficacy and safety.

Pre- and post-operative safety considerations for patients undergoing percutaneous nephrolithotomy

INTRODUCTION

Percutaneous nephrolithotomy (PCNL) is a widely used surgical procedure for treating large and complex kidney stones. Although effective, it carries risks of complications such as bleeding, infection, and injury to adjacent structures. Optimisation of procedural techniques and perioperative care can help minimize these risks.

AREAS COVERED

This review examines key pre- and post-operative safety considerations for PCNL patients. Topics include pre-operative imaging, patient positioning, puncture techniques, tract dilation, postoperative drainage, and complication management. The literature search involved analyzing recent studies and clinical guidelines to identify best practices. The search was conducted in several databases, including PubMed, Embase, the Cochrane Library and clinical guidelines. Training modalities for improving procedural skills are discussed.

EXPERT OPINION

Improving the safety of PCNL requires a combination of meticulous surgical technique, proper patient selection, and adherence to standardized protocols. Continuous skill development and technological advancements will further improve patient outcomes.

Risk of bleeding after retrograde intrarenal surgery vs miniaturised percutaneous nephrolithotomy for 10-20 mm renal stones: a not so different safety profile

OBJECTIVE

To assess differences in bleeding risk between retrograde intrarenal surgery (RIRS) and minimally invasive miniaturised percutaneous nephrolithotomy (mini-PCNL) for 10-20 mm renal stones.

PATIENTS AND METHODS

A total of 176 patients with a renal stone between 10 and 20 mm were treated. For all patients the Stone Management According to Size-Hardness (SMASH) score was calculated: Hounsfield units × stone maximum size (cm)/100. Patients with score of <15 underwent RIRS (90 patients, Group A), whereas patients with score ≥15 underwent mini-PCNL (86 patients, Group B). In both groups the Cyber Ho laser was used. A statistical analysis was carried out to assess differences in the risk of bleeding.

RESULTS

Preoperative features were comparable. The mean maximum stone diameter was 17.1 and 16.8 mm in Groups A and B, respectively (P = 0.13). The stone-free rate was comparable (87.8% vs 95.3%, P = 0.07). The overall complication rate was 14.4% and 18.6% in Groups A and B, respectively (P = 0.09). Gross haematuria was observed in five cases (5.5%) after RIRS and seven (8.1%) after mini-PCNL (P = 0.07). The mean haemoglobin drop was 12 and 2 g/L at the first and third postoperative day after RIRS vs 17 and 3 g/L after mini-PCNL (P = 0.06 and P = 0.21, respectively). Blood transfusions and renal embolisation were never necessary.

CONCLUSION

When managing renal stones between 10 and 20 mm taking into account both size and hardness with the application of the SMASH score, RIRS and mini-PCNL show comparable efficacy. A higher bleeding risk has been expected with percutaneous approaches; however, in our cohort the incidence of clinically significant bleeding was low and comparable between the two groups when adopting mini-PCNL.

Association Between Renal Pelvis Urine Density and the Risk of Infectious Complications after Retrograde Intrarenal Surgery

Introduction: Renal pelvis urine density (RPUD), as measured by computed tomography (CT), may serve as an effective predictor for pyonephrosis. Our objective was to evaluate the correlation between the likelihood of developing infectious complications post-retrograde intrarenal surgery (RIRS) and RPUD measurements obtained from preoperative CT scans. Materials and Methods: We retrospectively reviewed data from patients who underwent RIRS for kidney stone treatment at a tertiary care facility between June 2017 and June 2024, using the hospital's database. The patients were divided into two groups based on the development of postoperative infective complications. The groups were compared in terms of preoperative (demographic data, stone characteristic, and RPUD) and operation data. RPUD was measured by creating an ellipse much as possible area encompassing the renal pelvis on the treated side area encompassing the renal pelvis on the treated side, and the average Hounsfield unit (HU) value was recorded. Results: Postoperative infection developed in 31 of 588 patients (5.3%). The median RPUD value was 15 in the infective group and 8 in the noninfective group, with a statistically significant difference between the groups (p = 0.001). Body mass index, stone burden, stone density, and RPUD were associated with postoperative infection in the multivariate analysis (p = 0.001, p = 0.008, p = 0.007, and p = 0.001, respectively). Each unit increase in RPUD increased the risk of postoperative infection 1.107-fold. The receiver operating characteristic (ROC) analysis demonstrated a significant relationship between RPUD value and the risk of postoperative infection, with an area under the curve of 0.742 (p = 0.001). When the RPUD cut-off value was accepted as 14, sensitivity was 0.613 and specificity was 0.779. Conclusion: This study showed a significant association between HU values in RPUD and the risk of infectious complications following RIRS. This finding suggests that incorporating urine HU values from CT images into preoperative risk assessment could be crucial for infection prevention and management.

Flexible ureteroscopy combined with potassium sodium hydrogen citrate(PSHC) intervention improves the stone-free rate(SFR) for 20-30 mm uric acid renal stones

OBJECTIVE

To evaluate the efficacy and safety of combining flexible ureteroscopy (FURS) with potassium sodium hydrogen citrate(PSHC) for the treatment of 20-30 mm uric acid renal stones.

METHODS

A retrospective analysis of outcomes of patients with 20-30 mm uric acid renal stones who were treated with FURS and holmium lithotripsy was conducted between July 2021 and May 2024. Of them, 60 patients accepted FURS combined potassium sodium hydrogen citrate(PSHC) therapy while 70 patients underwent the FURS procedure alone. The demographic data, stone characteristics, surgical details, and perioperative outcomes of the patients were assessed retrospectively. Stone-free status was defined as the complete absence of stones on computed tomography.

RESULTS

Totally 130 patients were enrolled and analyzed in this study. No significant differences were found between the two groups in terms of gender, age, body mass index, comorbidities, stone burden, stone density, number of stones, or laterality. The mean operation time, American Society of Anesthesiologists (ASA) score, postoperative stay, and complication rate were also similar between the groups. The combined group incurred higher costs (p < 0.01),but it achieved significantly higher stone-free rate and Wisconsin Stone Quality of Life Questionnaire score at 4 weeks post-operatively (96.7% vs. 85.7%,p = 0.029;124.63 vs. 114.44,p < 0.01). Additionally, the combined group had a significantly higher urine pH at 4 weeks postoperatively compared to the non-combined group (6.63 vs. 5.50, p < 0.01).

CONCLUSION

Compared to a single procedure, FURS combined with PSHC therapy is an effective and safe treatment for 20-30 mm uric acid renal stones.

A narrative review on extracorporeal shock wave lithotripsy, ureterolithotripsy, and percutaneous nephrolithotripsy in patients with anomalous kidneys

INTRODUCTION

The aim of this paper was to review the outcomes of shock wave lithotripsy (SWL), ureteroscopy, and percutaneous nephrolithotripsy (PCNL) in kidney stone patients with Congenital Anomalies of the Kidney and Urinary Tract (CAKUT).

EVIDENCE ACQUISITION

A literature search was performed on 15th November 2023 and updated on 18th October 2024 using Cochrane Central Register of Controlled Trials, PubMed, Scopus and Google Scholar with no date limit. Preclinical and animal studies, reviews, letters to editor, case reports, pediatric studies were excluded. Only English papers were included.

EVIDENCE SYNTHESIS

Forty-one articles were accepted. Seventeen studies focused on horse-shoe kidney (HSK). Among these, 3 papers focused on RIRS, 9 on PCNL, 5 compared RIRS vs PCNL. The remaining ones explored SWL, RIRS, PCNL in ectopic, malrotated and medullary sponge kidney and caliceal diverticulum stones. HSK, caliceal diverticulum and malrotated kidneys stones treated with SWL have poor stone-free rate, while the best choices are PCNL and ureteroscopy. In ectopic kidneys the best choice is ureteroscopy, SWL has poor stone-free rate, while PCNL is less safe for higher bowel injury risk. In medullary sponge kidneys regardless of the treatment used, stone-free rate is low, with a higher rate of retreatment.

CONCLUSIONS

SWL has lower stone-free rate and higher retreatment in all types of CAKUT but has the lowest rate of complications. PCNL has the best stone-free rate in large stone burdens and RIRS is effective procedure although higher reintervention rate and need of pre-stenting in some cases.

Severe bleeding in patients following "tubeless" percutaneous nephrolithotomy: Predictors of angioembolization

INTRODUCTION

Percutaneous nephrolithotomy (PCNL) is a widely used procedure for treating renal calculi. Advanced techniques have improved outcomes, but hemorrhage remains a significant complication. While most cases of hemorrhagic complications are typically managed conservatively, few cases necessitate interventions like angioembolization (AE). The purpose of this study is to identify risk factors closely associated with severe bleeding post-PCNL requiring AE and to assess if these factors can independently predict the type of lesion [arteriovenous fistula (AVF) vs pseudoaneurysm (PA)].

MATERIALS AND METHOD

A retrospective analysis was conducted on 119 patients who underwent "tubeless" PCNL and experienced severe bleeding between January 2018 and December 2023. The study reviewed demographic characteristics, stone characteristics, perioperative factors, and adverse events. The chi-square test and Fisher's exact test were used for univariate analysis. Logistic regression analysis was used in binomial analysis with a value of p < 0.05 considered statistically significant.

RESULTS

Out of 119 patients, 51 required AE. Elevated preoperative serum creatinine levels (>1.5 mg/dl) [p = 0.01], upper pole access [p = 0.008], and a larger access sheath size (standard PCNL vs mini-PCNL) [p ⩽ 0.001] were found to be significantly associated with AE. Logistic regression analysis revealed standard PCNL was significantly associated with post-PCNL bleeding requiring AE (odds ratio [OR]: 50, 95% confidence interval [CI]: 6.529-382.90, p ⩽ 0.001). Stone size and co-morbidities showed no significant association with AE. The average duration of presentation of symptoms post PCNL was 13.6 days. Most patients underwent coiling for AE, with a clinical success rate of 94%.

CONCLUSION

Elevated serum creatinine levels, upper pole access, and tract size >24 Fr are more prone to post-tubeless PCNL severe bleeding, which requires renal AE. The findings suggest that early angiography and possible AE should be considered for at-risk patients. In the future, these predictors may be integrated into predictive models to improve patient risk stratification.

A new scoring system to predict febrile urinary tract infection after retrograde intrarenal surgery

The current study aimed to determine the risk factors and define a new scoring system for predicting febrile urinary tract infection (F-UTI) following retrograde intrarenal surgery (RIRS) by using machine learning methods. We retrospectively analyzed the medical records of patients who underwent RIRS and 511 patients were included in the study. The patients were divided into two groups: Group 1 consisted of 34 patients who developed postoperative F-UTI, and Group 2 consisted of 477 patients who did not. We applied feature selection to determine the relevant variables. Consistency subset evaluator and greedy stepwise techniques were used for attribute selection. Logistic regression analysis was conducted on the variables obtained through feature selection to develop our scoring system. The accuracy of discrimination was assessed using the receiver operating characteristic curve. Five of the 19 variables, namely diabetes mellitus, hydronephrosis, administration type, a history of post-ureterorenoscopy (URS) UTI, and urine leukocyte count, were identified through feature selection. Binary logistic regression analysis showed that hydronephrosis, a history of post-URS UTI, and urine leukocyte count were significant independent predictors of F-UTI following RIRS. These three factors demonstrated good discrimination ability, with an area under curve value of 0.837. In the presence of at least one of these factors, 32 of 34 patients (94.1%) who developed postoperative F-UTI were successfully predicted. This new scoring system developed based on hydronephrosis, a history of post-URS UTI, and urine leukocyte count can successfully discriminate patients at risk of F-UTI development after RIRS.

Matched pair analysis of wide versus narrow focus during shockwave lithotripsy for urolithiasis

PURPOSE

To compare stone clearance and complications between a 'wide' (9 × 50 mm) and 'narrow' shockwave focus (6 × 28 mm) when undertaking shockwave lithotripsy (SWL) in patients with renal or ureteric stones.

METHODS

Data from patients undergoing SWL using the dual focus Storz Modulith SLX-F2 lithotripter at a single centre were prospectively collected between February 2018 and September 2020. Patients were matched by stone size, location, and number of treatments. Stone clearance, re-presentation within 31 days, symptoms, complications, and need for post SWL-interventions were compared using McNemar's test.

RESULTS

Patients receiving wide focus SWL (WF-SWL, n = 152) were matched with patients receiving narrow focus SWL (NF-SWL, n = 152). Median stone size was 6 mm; energy delivered to WF-SWL and NF-SWL groups was comparable. Complete stone clearance was achieved in 55% of WF-SWL patients (n = 84) and 41% (n = 63) of NF-SWL patients (p = 0.04). Treatment was considered successful in 74% (n = 113) of WF-SWL cases and 66% (n = 100) of NF-SWL (p = 0.20). No difference in rates of readmission, post-procedural pain, haematuria, urinary tract infections, analgesia or antibiotic requirements were identified.

CONCLUSION

This service evaluation demonstrates no differences in rates of overall treatment success nor complications on comparing WF-SWL and NF-SWL.

Acknowledging acute kidney disease following ureteroscopy and laser lithotripsy: results from a tertiary care referral center

BACKGROUND

Acute kidney disease (AKD) is a recently described syndrome consisting of kidney function abnormalities lasting less than 3 months. Little is known regarding AKD following ureteroscopy (URS) and laser lithotripsy.

OBJECTIVE

To evaluate the occurrence and evolution of AKD in stone patients treated with URS.

MATERIALS AND METHODS

Data from 284 patients treated with URS for urinary stones were retrospectively analyzed. According to the KDIGO 2020 criteria, AKD was defined as postoperative acute kidney injury (AKI) occurrence, estimated glomerular filtration rate (eGFR) decrease ≥ 35%, or serum creatinine (SCr) increase ≥ 50%. AKI was defined as SCr increase ≥ 0.3 mg/dL or ≥ 50%. AKD evolution was evaluated 60 days post-URS. Data were analyzed using descriptive statistics. Univariable (UVA) and multivariable (MVA) logistic regression analyses tested the association of patients' characteristics and perioperative data with the occurrence of AKD.

RESULTS

Overall, postoperative AKD occurred in 32 (11.3%) patients. Recovery from AKD was found in 26 (82%) patients and persistent AKD occurred in 6 (18%) patients. At UVA, age at surgery (p = 0.05), baseline SCr (p = 0.02), baseline CKD category (p = 0.006), Charlson comorbidity index (p = 0.01), operative time (p = 0.04) and postoperative complications (< 0.001) were associated with AKD. At MVA, CKD category (OR 2.99, 95% CI = 1.4-6.3; p = 0.004), operative time (OR 1.01, 95% CI = 1.001-1.018; p = 0.023) and postoperative complications (OR 3.5, 95% CI = 1.46-8.49; p = 0.005) were independent predictors of AKD.

CONCLUSIONS

AKD is a frequent complication in patients treated with URS. Moreover, AKD persists in a non-neglectable percentage of patients at medium-term follow-up. Therefore, nephrological assessment should be considered, especially in high-risk patients. Current findings should be considered for the peri-operative management of stone patients.

Complications of Single-Use Flexible Ureteroscopy vs. Reusable Flexible Ureteroscopy: A Narrative Review

Urolithiasis, or kidney stones, is a painful condition that is becoming increasingly common worldwide. For many, the solution lies in a minimally invasive procedure called flexible ureteroscopy (fURS). This technique involves inserting a tiny, flexible scope into the urinary tract to break up and remove stones. Reusable fURS scopes have traditionally been the norm. However, concerns about infection control and instrument durability have led to the development of single-use scopes. While both methods offer effective treatment, the question remains: which one is safer and more efficient? To answer this, we conducted a comprehensive review of the available research. We analyzed 37 studies that compared single-use and reusable fURS complication rates. While both methods carry risks, such as bleeding, infection, and ureteral injury, the overall complication rates were found to be similar. As technology continues to advance, fURS is becoming even safer and more effective. However, there is still a need for standardized reporting and further research to better understand the potential risks and benefits of both single-use and reusable scopes. Ultimately, the choice between the two will depend on various factors, including patient factors, surgeon preference, and healthcare resource availability.

Flank-free modified supine vs. prone position for pediatric nephrolithotripsy: an updated systematic review and meta-analysis

INTRODUCTION

Percutaneous nephrolithotomy (PCNL) is widely performed as the preferred treatment for kidney stones larger than 20 mm in pediatric patients, with current research focusing on comparing outcomes between prone and supine positions to determine optimal procedural positioning. Therefore, the aim of this study is to compare the efficacy of prone versus supine positioning in pediatric PCNL, providing clarity on this critical aspect of the procedure to guide clinical decision-making.

METHODS

We conducted a systematic review in PubMed, Embase, Scopus, Cochrane, Web of Science and Google Scholar. We included studies that compared PCNL in prone vs supine positions for pediatric patients. Our primary outcome was stone-free rate (SFR). Secondary outcomes included operative time, length of hospital stay and overall complications rate. The statistical analysis was performed using Review Manager 5.4.

RESULTS

We retrieved 8 articles, with 269 patients in the prone group and 223 patients in the supine group. The mean age of all patients was 7.92 years old. Our findings presented no statistically significant difference in SFR between the two positions (OR 0.67; CI95 0.38, 1.18; p = 0.17; I2 = 0%). Additionally, we noted a significant reduction in operative time in the supine position group (MD 13.75; CI95 4.35, 23.15; p = 0.004; I2 = 84%). At the same time, the length of hospital stay after the procedure was lower in supine group (MD 0.61; CI95 0.34, 0.88; p < 0.0001; I2 = 21%). No difference was observed regarding the total complication rate (OR 1.47; CI95 0.88, 2.47; p = 0.15; I2 = 0%).

CONCLUSION

Our meta-analysis suggests that PCNL performed in the prone position is equivalent to supine PCNL in terms of SFR. However, mainly in the RCT studies, we could observe benefits of the supine position in comparison of prone position in terms of lower operative time, as well as a reduced postoperative hospital stay.

Microchannel percutaneous nephrolithotomy versus flexible ureteroscopic lithotripsy for the treatment of 1-2 cm high hardness single upper ureteral stones: a propensity score-matched study

The objective of this study was to compare the clinical efficacy and safety of microchannel percutaneous nephrolithotripsy (MPCNL) with flexible ureteroscopic lithotripsy (FURL) in the treatment of single upper ureteral stones with a diameter of 1-2 cm and high hardness. This study retrospectively analyzed 89 patients diagnosed with a single upper ureteral stone with a 1-2 cm diameter and a computed tomography value > 1000 Hounsfield units. A propensity score matching system matched this study with factors to minimize the effect of baseline differences between patients. Ultimately, 29 patients in each of the two groups were successfully matched. The stone-free rate was marginally higher in the MPCNL group than in the FURL group (93.10% vs. 86.21%), although the difference did not reach statistical significance (P = 0.666). Furthermore, the mean operative time in the MPCNL group, although slightly longer than that in the FURL group, did not demonstrate a statistically significant difference (P = 0.833). However, patients in the MPCNL group exhibited a significantly more substantial decrease in hemoglobin than those in the FURL group (P < 0.001) and a substantially more extended postoperative hospital stay (P < 0.001). Regarding perioperative complications, the incidence of moderate pain was higher in the MPCNL group than in the FURL group (P = 0.037). The difference in overall complication rates between the two groups did not reach statistical significance (P = 0.108). MPCNL and FURL are efficacious surgical procedures for treating single upper ureteral stones with a 1-2 cm diameter and high hardness.

Does tilt-retrograde intrarenal surgery enhance stone clearance and offer better surgical ergonomics in patients with renal calculi? A prospective randomized control study

INTRODUCTION

Retrograde intrarenal surgery (RIRS) is the standard treatment for renal calculi. Direct visualization and fragmentation are its major advantages. The variable stone clearance rates and the ergonomic challenges faced by urologists are a few limitations. Table tilt enhances stone clearance and improves surgical ergonomics by facilitating better access to stones and reducing procedural strain.

SUBJECTS AND METHODS

In this prospective study, patients with intrarenal calculi were randomized into standard lithotomy RIRS (S-RIRS) and table-tilted RIRS (T-RIRS) groups. Specified table tilts were suggested for each of the stone locations. The outcomes with regard to stone clearance, operative and lasing time, and ergonomics were studied.

RESULTS

About 100 patients were studied, with 50 in each group. The overall operating time and lasing time in the T-RIRS group were less than that in the S-RIRS group (P < 0.001). The complication rates were the same in both groups. Most surgeons felt that the surgical ergonomics was better in the T-RIRS group (P < 0.001). When stone-free status was analyzed, seven patients in the S-RIRS group and one in the T-RIRS group had residual stones. The mean Borg category-ratio 10 (CR-10) scores in the S-RIRS and T-RIRS groups were 4.18 and 2.20, respectively (P < 0.001).

CONCLUSIONS

This is the first study to document the distinct advantages of T-RIRS and its benefits on surgical ergonomics. T-RIRS resulted in significantly shorter operative and lasing times, particularly for stones in lower calyces. Surgical ergonomics, assessed by the Borg CR-10 scale, were significantly better in the T-RIRS group. T-RIRS should become a standard of care for patients undergoing RIRS.

Exploring the competency of the comprehensive complication index over the clavien-dindo classification in standard percutaneous nephrolithotomy: a call for better complication reporting

PURPOSE

The Comprehensive Complication Index (CCI) was introduced in 2013 to overcome the limitations of the Clavien-Dindo Classification (CDC) in grading postoperative complications. The objective of this study to assess the predictive value of the CDC and the CCI for postoperative course in patients undergoing standard adult percutaneous nephrolithotomy (PCNL).

METHODS

A retrospective analysis of 320 renal units that underwent standard PCNL between July 2021 - April 2023 was conducted. The CDC and CCI systems assessed complications occurring within the first 30 days after surgery. A second CCI score was calculated only on the highest CDC grade, and this score was referred to as the noncumulative CCI. A comparative analysis was conducted to determine the predictive efficacy of both evaluation methods regarding the postoperative course.

RESULTS

The postoperative complication rate was 23.1% (74/320). Eight patients (2.5%) experienced multiple complications, resulting in a higher total CCI score than the noncumulative CCI (p = 0.010). Correlation analysis revealed that the CCI correlated with the length of hospital stay (LOS) more precisely than the noncumulative CCI (CCI: r = 0.335; p = 0.004 vs. noncumulative CCI: r = 0.325; p = 0.005). Compared with patients with a single complication, those with multiple complications had similar demographics, preoperative stone characteristics, and intraoperative features.

CONCLUSION

Cumulative CCI proves to be a more effective predictor of LOS and complication burden in standard PCNL than CDC. Hence, using CCI to evaluate complications after PCNL may be a more appropriate approach.

Incidence of metabolic syndrome in patients with unilateral or bilateral staghorn renal stones and its impact on percutaneous nephrolithotomy outcomes

BACKGROUND

To evaluate the incidence of metabolic syndrome (MetS) in patients with unilateral and bilateral staghorn calculi (SC) and evaluate the impact on the outcome of percutaneous nephrolithotomy (PCNL).

METHODS

The clinical data of patients who underwent PCNL for the treatment of SC between 2019 and 2022 were retrospectively reviewed. SC was divided into unilateral and bilateral. The incidence of MetS was compared between the patients with unilateral SC and the patients with bilateral SC, and the impact on the outcome of PCNL was assessed.

RESULTS

A total of 1778 patients underwent PCNL between 2019 and 2022. After screening computed tomography, 379 patients were confirmed to have SC, finally, leaving 310 patients with follow-up and complete data to be included in the study. Eighty-four had bilateral SC and 226 had unilateral SC. The patients with bilateral SC had a significantly higher body mass index and higher rates of complete staghorn stones and metabolic syndrome. Higher body mass index, hypertension, diabetes mellitus, hyperlipidaemia, and MetS were present in 62.58%, 44.84%, 21.94%, 60.65% and 27.42% of all patients, respectively. The number of MetS components remained significantly associated with bilateral SC. Specifically, when the number of MetS components increases from 0 to 3-4, the likelihood of developing bilateral staghorn calculi increases by 21.967 times. Eighty-five patients with MetS( +) had a higher rate of overall complications (number (N)(%), 29 (34.12) vs.33 (14.46), P < 0.001) and a comparable stone-free rate to 225 MetS(-) patients. Multivariable analysis confirmed that hyperlipidaemia (P = 0.044, odds ratio [OR] = 1.991, 95% confidence interval [CI] 1.020-3.888) and MetS (P = 0.005, OR = 2.427, 95% CI 1.316-4.477) were independent risk factors for overall complications.

CONCLUSIONS

MetS is correlated with the formation of bilateral SC and is the main predictor for complications of PCNL especially for low-grade complications (I-II).

Recent advances in the treatment of renal stones using flexible ureteroscopys

Upper urinary tract stones are a common urological disease that can be treated by flexible ureteroscopy (FURS) through the natural urinary tract, in addition to extracorporeal shock wave lithotripsy and percutaneous nephrolithotomy. The advantages of FURS are less trauma, faster recovery, and fewer complications, while its disadvantages include poor results of lithotripsy and stone extraction when dealing with larger stones, and prolonged operation time. Over the last two decades, the emergence of new technologies such as FURS combined with negative pressure suction, robot-assisted FURS, and artificially intelligent FURS, coupled with improvements in laser technology (the use of thulium fiber lasers and the invention of single-use flexible ureteroscopes (su-fURS) suitable for primary level application, have significantly increased the global adoption of FURS. This surge in usage holds a promising future in clinical application, benefiting a growing number of patients with renal calculi. Accompanied by changes in technical concepts and therapeutic modalities, the scope of indications for FURS is broadening, positioning it as a potential primary choice for urolithiasis treatment in the future. This review outlines the progress in employing FURS for the treatment of renal calculi in order to generate insights for further research.

URS for de-novo urolithiasis after kidney transplantation: a systematic review of the literature

INTRODUCTION

There is a gap in the available literature and guidelines concerning the optimal approach for treating allograft stones, which currently include external shockwave lithotripsy, ureteroscopy and laser lithotripsy, or percutaneous nephrolithotomy. The objective of this systematic review was to evaluate the safety and effectiveness of URS as a treatment option for patients in this scenario.

EVIDENCE ACQUISITION

A comprehensive search of the literature was conducted until August 2023. Only original articles written in English were considered for inclusion. This review has been registered in PROSPERO (registration number CRD42023451154).

EVIDENCE SYNTHESIS

Eleven articles were included (122 patients). The mean age was 46.9±9.5 years, with a male-to-female ratio of 62:49. The preferred ureteral reimplantation technique was the Lich-Gregoire. The mean onset time was 48.24 months. Acute kidney injury, urinary tract infections and fever were the most frequent clinical presentations (18.3% each), followed by hematuria (10%). The mean stone size measured 9.84 mm (±2.42 mm). Flexible URS was preferred over semirigid URS. The stone-free rate stood at 83.35%, while the overall complication rate was 13.93%, with six (4.9%) major complications reported. Stones were mainly composed of calcium oxalate (42.6%) or uric acid (14.8%). Over an average follow-up period of 30.2 months, the recurrence rate was 2.46%. No significant changes in renal function or allograft loss were reported.

CONCLUSIONS

URS remains an efficient choice for addressing de-novo allograft urolithiasis, offering the advantage of treating urinary stones with a good SFR and a low incidence of complications. Procedures should be performed in an Endourology referral center.

Application of AI in urolithiasis risk of infection: a scoping review

INTRODUCTION

Artificial intelligence and machine learning are the new frontier in urology; they can assist the diagnostic work-up and in prognostication bring superior to the existing nomograms. Infectious events and in particular the septic risk, are one of the most common and in some cases life threatening complication in patients with urolithiasis. We performed a scoping review to provide an overview of the current application of AI in prediction the infectious complications in patients affected by urolithiasis.

EVIDENCE ACQUISITION

A systematic scoping review of the literature was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses for Scoping Reviews (PRISMA-ScR) guidelines by screening Medline, PubMed, and Embase to detect pertinent studies.

EVIDENCE SYNTHESIS

A total of 467 articles were found, of which nine met the inclusion criteria and were considered. All studies are retrospective and published between 2021 and 2023. Only two studies performed an external validation of the described models. The main event considered is urosepsis in four articles, urinary tract infection in two articles and diagnosis of infection stones in three articles. Different AI models were trained, each of which exploited several types and numbers of variables. All studies reveal good performance. Random forest and artificial neural networks seem to have higher AUC, specificity and sensibility and perform better than the traditional statistical analysis.

CONCLUSIONS

Further prospective and multi-institutional studies with external validation are needed to better clarify which variables and AI models should be integrated in our clinical practice to predict infectious events.

Assessment of Effectiveness and Safety of Aspiration-Assisted Nephrostomic Access Sheaths in PCNL and Intrarenal Pressures Evaluation: A Systematic Review of the Literature

Background: Different suction-assisted nephrostomic sheaths have been developed for percutaneous nephrolithotomy (PCNL). Objectives: (1) To examine PCNL techniques performed with different aspiration-assisted sheaths (Clear Petra® sheath, Superperc, SuperminiPCNL, and a miniPCNL patented sheath), with specific regard to effectiveness and safety outcomes in adult and paediatric patients; (2) to extrapolate intrarenal pressure (IRP) data during these procedures. Methods: A systematic literature search was performed in accordance with PRISMA guidelines. Relevant articles up to 8 February 2024 were included. Results: Twenty-five studies were selected, thirteen retrospective and twelve prospective. The use of four different aspirating sheaths for miniPCNL was reported: Clear Petra® sheath, Superperc, SuperminiPCNL, and a miniPCNL patented sheath. Stone free rates (SFRs) across techniques ranged from 71.3% to 100%, and complication rates from 1.5% to 38.9%. Infectious complication rates varied from 0 to 27.8% and bleeding complication rates from 0 to 8.9%. Most complications were low grade ones. The trend among studies comparing aspiration- and non-aspiration-assisted miniPCNL was towards equivalent or better SFRs and lower overall infectious and bleeding complication rates in suction techniques. Operation time was consistently lower in suction procedures, with a mean shortening of the procedural time of 19 min. Seven studies reported IRP values during suction miniPCNL. Two studies reported satisfactory SFRs and adequate safety profiles in paediatric patient cohorts. Conclusions: MiniPCNL with aspirating sheaths appears to be safe and effective in both adult and paediatric patients. A trend towards a reduction of overall infectious and bleeding complications with respect to non-suction procedures is evident, with comparable or better SFRs and consistently shorter operative times. The IRP profile seems to be safe with the aid of aspirating sheaths. However, high quality evidence on this topic is still lacking.

Analyzing global research trends and focal points in the utilization of laser techniques for the treatment of urolithiasis from 1978 to 2022: visualization and bibliometric analysis

Laser lithotripsy is gaining global prominence and is a dynamically progressing field marked by a continual influx of new and comprehensive research each year. Recently, there has been a noticeable shift toward the adoption of various kinds of lasers, such as holmium: yttrium-aluminum-garnet (Ho:YAG) and thulium fiber (TFL) lasers. Consequently, we aim to conduct a bibliometric analysis to analyze key areas of research activity within scientific publications that center on the utilization of laser techniques in urolithiasis. A search of the literature spanning from 1978 to 2022 was carried out on 25 December 2023 using the Scopus database to explore research related to the application of laser techniques for urolithiasis treatment. Visualization analysis was performed using VOSviewer software (version 1.6.20). We examined 962 publications that met the specified criteria, 791 (82.22%) of which were original articles. The analysis of the retrieved publications indicated a consistent increase in research output from 1978 to 2022; a particularly noteworthy surge occurred after 2003. In particular, the U.S. claimed the leading position as the most productive country, contributing 211 articles (21.93%). However, India had the highest research productivity according to the adjustment index of 19.08. In the European region, 324 publications (33.68% of the total) originated from 25 countries. The Journal of Endourology contributed the most between 1978 and 2022 (n = 96, 9.98%). The most cited paper examined the effectiveness of holmium: yttrium-aluminum-garnet (Ho:YAG) lasers, while a subsequent study focused on the use of a thulium fiber laser (TFL), an emerging laser technology that has gained increased recognition. Co-occurrence analysis revealed three distinct clusters focusing on the types of laser technology, minimally invasive approaches, and success rate/postoperative complications. This comprehensive investigation delves into the global landscape of laser use for the treatment of urolithiasis. This review supports the emerging clinical concept of using various types of laser technology for urolithiasis treatment. Moreover, the hot issues that researchers should focus on based on the findings of this study are the use of different types of laser lithotripsy in view of the surgical approach, success rate and complications.

Develop a radiomics-based machine learning model to predict the stone-free rate post-percutaneous nephrolithotomy

Radiomics and machine learning have been extensively utilized in the realm of urinary stones, particularly in forecasting stone treatment outcomes. The objective of this study was to integrate clinical variables and radiomic features to develop a machine learning model for predicting the stone-free rate (SFR) following percutaneous nephrolithotomy (PCNL). A total of 212 eligible patients who underwent PCNL surgery at the Second Affiliated Hospital of Nanchang University were included in a retrospective analysis. Preoperative clinical variables and non-contrast-enhanced CT images of all patients were collected, and radiomic features were extracted after delineating the stone ROI. Univariate analysis was conducted to identify clinical variables strongly correlated with the stone-free rate after PCNL, and the least absolute shrinkage and selection operator algorithm (lasso regression) was utilized to screen radiomic features. Four supervised machine learning algorithms, including Logistic Regression, Random Forest (RF), Extreme Gradient Boosting (XGBoost), and Gradient Boosting Decision Tree (GBDT), were employed. The clinical variables with strong correlation and screened radiomic features were integrated into the four machine learning algorithms to construct a prediction model, and the receiver operating curve was plotted. The area under the receiver operating curve (AUC), the accuracy rate, the specificity, etc., were used to evaluate the predictive performance of the four models. After analyzing postoperative statistics, the stone-free rate following the procedure was found to be 70.3% (n = 149). Among the various clinical variables examined, factors, such as stone number, stone diameter, stone CT value, stone location, and history of stone surgery, were identified as statistically significant in relation to the stone-free rate after PCNL. A total of 121 radiomic features were extracted, and through lasso regression, 7 features most closely associated with the stone-free rate post-PCNL were identified. The predictive accuracy of different models (Logistic Regression, RF, XGBoost, and GBDT) for determining the stone-free rate after PCNL was evaluated, yielding accuracies of 78.1%, 76.6%, 75.0%, and 73.4%, respectively. The corresponding area under the curve AUC (95%CI) were 0.85 (0.83-0.89), 0.81 (0.76-0.85), 0.82 (0.78-0.85), and 0.77 (0.73-0.81), positioning these models among the top performers in logistic regression prediction. In terms of predictive importance scores, the key factors identified by the logistic regression model were number of stone, zone percentage, stone diameter, and surface area. Similarly, the RF model highlighted number of stone, stone CT value, stone diameter, and surface area as the top predictors. Among the four machine learning models, the logistic regression model demonstrated the highest accuracy and discrimination ability in predicting the stone-free rate following PCNL. In comparison to XGBoost and GBDT, RF also exhibited superior accuracy and a certain level of discrimination ability. However, based on the performance of all four models, logistic regression is more likely to aid in clinical decision-making by assisting clinicians in diagnosing PCNL in patients. This enables us to effectively predict the presence of residual stones post-surgery and ultimately select patients who are suitable candidates for PCNL.

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.

Transient ureteral obstruction after mini-percutaneous nephrolithotomy is associated with stone volume and location: results from a single-center, real-life study

PURPOSE

To evaluate the rate of and predictors of ureteral obstruction after mini-percutaneous nephrolithotomy (mPCNL) for kidney stones.

METHODS

We analyzed data from 263 consecutive patients who underwent mPCNL at a single tertiary referral academic between 01/2016 and 11/2022. Patient's demographics, stone characteristics, and operative data were collected. A nephrostomy tube was placed as the only exit strategy in each procedure. On postoperative day 2, an antegrade pyelography was performed to assess ureteral canalization. The nephrostomy tube was removed if ureteral canalization was successful. Descriptive statistics and logistic regression models were used to identify factors associated with a lack of ureteral canalization.

RESULTS

Overall, median (IQR) age and stone volume were 56 (47-65) years and 1.7 (0.8-4.2) cm3, respectively. Of 263, 55 (20.9%) patients showed ureteral obstruction during pyelography. Patients without ureteral canalization had larger stone volume (p < 0.001), longer operative time (p < 0.01), and higher rate of stones in the renal pelvis (p < 0.01) than those with normal pyelography. Length of stay was longer (p < 0.01), and postoperative complications (p = 0.03) were more frequent in patients without ureteral canalization. Multivariable logistic regression analysis revealed that stone volume (OR 1.1, p = 0.02) and stone located in the renal pelvis (OR 2.2, p = 0.04) were independent predictors of transient ureteral obstruction, after accounting for operative time.

CONCLUSION

One out of five patients showed transient ureteral obstruction after mPCNL. Patients with a higher stone burden and with stones in the renal pelvis are at higher risk of inadequate ureteral canalization. Internal drainage might be considered in these cases to avoid potential complications.

A novel model of urosepsis in mice developed by ureteral ligation and injection of Escherichia coli into the renal pelvis

Despite extensive investigations, urosepsis remains a life-threatening and high-mortality illness. The absence of widely acknowledged animal models for urosepsis prompted this investigation with the objective of formulating a replicable murine model. Eighty-four adult male C57BL/6J mice were arbitrarily distributed into three cohorts based on the concentration of the Escherichia coli (E. coli) solution administered into the renal pelvis: Sham, Low-grade sepsis (1.0 × 108 cfu/mL), and High-grade sepsis (1.0 × 109 cfu/mL). By fabricating a glass needle with a 100 μm outer diameter, bacterial leakage during renal pelvic injection was minimized. After the ureteral ligation, the mice were injected with this needle into the right renal pelvis (normal saline or E. coli solution, 1 ml/kg). Ten days post after E. coli injection, the mortality rates for the Low-grade sepsis and High-grade sepsis groups stood at 30 % and 100 %, respectively. Post-successful modeling, mice in the urosepsis cohort exhibited a noteworthy reduction in activity, body temperature, and white blood cell count within a 2-h timeframe. At the 24-h mark post-modeling, mice afflicted with urosepsis displayed compromised coagulation functionality. Concurrently, multiple organ dysfunction was confirmed as evidenced by markedly elevated levels of inflammatory factors (IL-6 and TNF-α) in four distinct organs (heart, lung, liver, and kidney). This study confirmed the feasibility of establishing a standardized mouse model of urosepsis by ureteral ligation and E. coli injection into the renal pelvis. A primary drawback of this model resides in the mice's diminished blood volume, rendering continuous blood extraction at multiple intervals challenging.

Ileal ureter replacement and ileocystoplasty for the treatment of bilateral ureteral strictures and bladder contracture: technique and outcomes

BACKGROUND

The aim of this study was to explore the feasibility of ileal ureter replacement and ileocystoplasty for the treatment of bilateral long-segment ureteral strictures combined with bladder contracture.

METHODS

A retrospective review of clinical data from seven patients who underwent bilateral Ileal Ureter Replacement and ileocystoplasty from April 2019 to February 2023 was conducted. The surgeries were performed using open, laparoscopic, and robot-assisted laparoscopic approaches. Baseline characteristics, perioperative, and mid-term results of the patients were collected. Follow-up period of 3-28 months. A detailed description of the technique was reported.

RESULTS

The mean age of the patients was 52.86±6.06 years. The average duration of surgery was 365±28.54 minutes, and the estimated intraoperative blood loss was 357.14±184.06 mL. The mean length of harvested ileum was 37.86±8.40 cm. The preoperative serum creatinine level was 88.02±18.05 μmol/L, postoperative day 1 creatinine level was 90.7±12.93μmol/L, postoperative 3-month creatinine level was 93.77±33.34 μmol/L, and the mean creatinine level at the last follow-up was 94.89±27.89μmol/L. The postoperative bladder capacity was 249.43±32.50 mL on average. The average length of hospital stay was 26.57±15.46 days. No complications of Clavien-Dindo grade 3 or higher were observed. During the follow-up period, no patients experienced deterioration of renal function after surgery.

CONCLUSIONS

Bilateral ileal ureter replacement and ileocystoplasty are effective surgical technique for the treatment of bilateral long-segment ureteral strictures combined with bladder contracture caused by radiation therapy.

JJ stent dislodgement in the distal ureter: how to recover it in preschool children?

Double-J ureteral stents are usually placed after various urological procedures. The dislodgement of their distal ringlet is a rare complication, whose retrieval is arduous in younger children, due to the small ureteral caliber. We propose our innovative endoscopic approach to recover the dislodged JJ stent. Under 8-9.8 Ch cystoscopy, the ureteral meatus is gently cannulated with a 00.18″ guidewire, then a balloon catheter Passeo 18 3-4 mm (Biotronik, Lake Oswego, OR, USA) is coaxially inserted. A pneumatic dilatation of the vesical-ureteral junction is performed up to 8 atmospheres for 5 minutes under direct vision. Consequently, the ureteral meatus allows the cystoscope passage, and the JJ-stent can be recovered thanks to endoscopic grasping forceps. A mono-J stent is then left in place for 24 hours. Four patients aged 8 months - 4 years have been successfully treated with this approach after that JJ migration was found intraoperatively or during ultrasonography. No intra- or postoperative complications occurred. Postoperative hospital stay was prolonged for one day. During 29.5 medium follow-up no clinical or ultrasonographic signs of vesical-ureteral reflux ensued. Our cystoscopic approach is effective and safe to ensure a prompt endoscopic JJ retrieval without changing neither surgical approach nor the anesthesiological support. We believe that all the pediatric urology centers should know the procedure and have small size balloon catheter available.

Initial experience with robot-assisted ureteroscopy with Ily® Robot

The aim of this study is to present the first Italian experience with robotic-assisted retrograde intrarenal surgery (rRIRS) using the Ily® platform. Procedures were performed for renal stones using the Ily® Robot (STERLAB, Vallauris, France), which is a ureteroscope holder with multiple degrees of freedom that can be controlled remotely through a wireless controller. In March 2023, consecutive patients with indications for rRIRS were included in the study. Demographic variables and stone characteristics were collected, and standard perioperative data were assessed. The one-month stone-free rate (SFR, i.e. no residual fragments) was evaluated using ultrasound. All participating surgeons filled out a Surgeons' Satisfaction Questionnaire (SSQ) based on a Likert-type scale. The questionnaire focused on: 1) ease of use; 2) ergonomics during renal cavity exploration; 3) stability during stone fragmentation. Among the patients, one had bilateral stones, while two had stones on the right side. The mean stone size was 13 mm. The average operative time was 70 minutes and the mean docking time was three minutes. No perioperative complications were recorded, and all patients were discharged on the first postoperative day. The one-month SFR was 100%. The SSQ scores were as follows: 1) ease of use: 4/5; 2) ergonomics: 5/5; 3) stability during stone fragmentation: 5/5. Based on the initial experience, the results indicate the feasibility, safety, and effectiveness of rRIRS. The ergonomic efficiency of the system was highly appreciated by the surgeons. While a cost-effectiveness analysis within clinical trials is necessary, rRIRS shows the potential for a more sustainable future for endoscopists and an improved workplace environment.

Translation and validation of the Italian version of the Wisconsin Stone Quality of Life Questionnaire (I-WISQOL) for assessing quality of life in patients with urolithiasis

BACKGROUND

Urolithiasis is a chronic condition, and it has been associated with a significant negative impact on patients' health-related quality of life (HRQOL). Several tools to assess patients' HRQOL have been validated in Italian, however disease-specific HRQOL instruments are still lacking. We aimed to develop and validate the Italian version of the WISQOL (I-WISQOL) in patients with urolithiasis.

METHODS

The Italian version of the WISQOL was developed in a multistep process involving primary translation, back-translation, and pilot testing among a group of patients (N.=10). Patients presenting with urolithiasis were prospectively recruited from the outpatient stone clinics and completed both questionnaire WISQOL and SF-36. Demographic information, as well as medical and surgical data, were obtained through an interview. Internal consistency of the I-WISQOL was obtained with Cronbach's α. Correlation of total scores of the I-WISQOL and SF36 was assessed to determine convergent validity using Spearman Rho. Correlations between clinical variables and results from the I-WISQOL were analyzed to descriptively assess the association of interest.

RESULTS

A total of 93 participants were evaluated and completed the Italian version of the I-WISQOL. The I-WISQOL demonstrated excellent internal consistency (Cronbach's α 0.95) and good convergent validity with the validated SF-36 (Spearman Rho r=0.70, P<0.001). Using ANOVA analysis, a significant decline in WISQOL Score was noted with the increasing number of renal colics (P=0.0543), ER visits (P=0.037), number of inpatient hospitalization (P=0.025). At multivariate analysis, worse WISQOL total score was predicted by a greater number of renal colic events (ß=-4.92 [-8.81-1.04], P=0.014) and by a greater number inpatient hospitalization (ß=-7.31 [-14.35 -0.26], P=0.042).

CONCLUSIONS

The I-WISQOL is an internally consistent and valid instrument to assess HRQOL in Italian-speaking patients with kidney stones. Its use in clinical practice should be implemented in order to tailor the management of each patient.

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

BACKGROUND

Retrograde Intrarenal Surgery (RIRS) is recommended as an alternative to percutaneous nephrolithotomy for stones up to 2 cm. Pre-stenting before RIRS remains controversial with various studies differing in outcomes and recommendations. We aim to understand how pre-stenting influences surgical outcomes.

METHODS

A number of 6579 patients from the TOWER group registry were divided into pre-stented (group 1) and non-pre-stented groups (group 2). Patients aged ≥18 years old, with normal calyceal anatomy were enrolled. Patients with ureteric stones, anomalous kidneys, bilateral stones, planned for ECIRS were excluded.

RESULTS

Patients are homogeneously distributed in both groups (3112 vs. 3467). The predominant indication for pre-stenting was symptom relief. Overall stone size was comparable, whilst group 1 had a significantly more multiple (1419 vs. 1283, P<0.001) and lower-pole (LP) stones (1503 vs. 1411, P<0.001). The mean operative time for group 2 was significantly longer (68.17 vs. 58.92, P<0.001). Stone size, LP stones, age, recurrence and multiple stones are contributing factors for residual fragments at the multivariable analysis. The incidence of postoperative day 1 fever and sepsis was significantly higher in group 2, indicating that pre-stenting is associated with a lower risk of post-RIRS infection and a lower overall complications rate (13.62% vs. 15.89%) (P<0.001).

CONCLUSIONS

RIRS without pre-stenting can be considered safe without significant morbidity. Multiple, lower-pole and large stone is a significant contributor towards residual fragments. Patients who were not pre-stented had significantly higher but low-grade complications, especially for lower pole and large volume stones. While we do not advocate routine pre-stenting, a tailored approach for these patients should include proper counselling regarding pre-stenting.

Optimizing Outcomes in Flexible Ureteroscopy: A Narrative Review of Suction Techniques

OBJECTIVE

The aim of this review is to summarize the existing suction systems in flexible ureteroscopy (fURS) and to evaluate their effectiveness and safety.

METHODS

A narrative review was performed using the Pubmed and Web of Science Core Collection (WoSCC) databases. Additionally, we conducted a search on the Twitter platform. Studies including suctions systems in fURS were included. Editorials, letters and studies reporting intervention with semirigid ureteroscopy, PCNL and mPCNL were excluded.

RESULTS

A total of 12 studies were included in this review. These studies comprised one in vitro study, one ex vivo study, one experimental study and eight cohort studies. The Pubmed and WoSCC searches identified three suction techniques (Irrigation/Suctioning system with control of pressure, suction ureteral access sheath (sUAS) and direct in scope suction (DISS)), and the Twitter search identified four of them. The overall results showed that suction is an effective and safe technique that improves stone-free rates, reduces operative time and limits complication rates after fURS.

CONCLUSIONS

The use of suctioning during common endourological procedures has been shown to improve safety and efficacy in several indications. However, randomized controlled trials are needed to confirm this.

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 Ureteroscope Performance between Reusable and Single-Use Models

BACKGROUND

Single-use flexible ureteroscopes for urinary retention have been developed in recent years as an alternative to reusable ureteroscopes in order to eliminate the risk of cross-infections and to solve the primary limitations of traditional reusable flexible ureteroscopes for urinary retention.

METHODS

In this study, we evaluated and contrasted three of the most recent types of flexible ureteroscopes, including two digital reusable versions (Olympus URF-V and Olympus URF-V2) and one single-use model (Pusen Medi-calUscope UE3022), in both ex vivo and in vivo scenarios. The influence of a variety of instruments on the flow of irrigation and its deflection was investigated ex vivo. In the in vivo investigation, a total of 40 patients were treated with retrograde fURS utilizing URF-V, 20 patients were treated with URF-V2, and 20 patients were treated with single-use fURS. The visibility and maneuverability of each fURS were evaluated by the same urologist during the procedures, and the results were compared.

RESULTS

Intraoperatively, we compared the image quality of reusable (URF-V and URF-V2) and single-use fURS USCOPE UE3022 cameras and found that there was no statistically significant difference between the two types of camera. The score for maneuverability was the same (4.2) regardless of whether we used the UscopeUE3022 or the URF-V2, but it was significantly lower (3.8, p = 0.03) when we utilized the URF-V. Irrigation was about the same when utilizing reused scopes, whereas employing a single-use scope was more than fifty percent more effective.

CONCLUSIONS

The findings of our research indicate that reusable and single-use fURs have visibility and maneuverability characteristics that are at least comparable to one another. The possibilities of the single-use type in terms of irrigation flow and deflection are superior.

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

OBJECTIVE

To analyze the pattern of speaker activity related to both flexible ureteroscopy (fURS) and percutaneous nephrolithotomy (PCNL) during plenary sessions at the main (endo)urological international meetings over the last 10 years.

METHODS

We reviewed the meeting programs of the main endourological international meetings (EAU, AUA, WCE, and SIU) during 2011-2019. We detected all invited speakers at plenary sessions regarding fURS or PCNL. The proportion of fURS and PCNL talks was evaluated yearly during the study period. In order to analyze plenary session speaker composition, we estimated and compared the mean number of talks per speaker according to surgical technique. We also analyzed possible differences in age distribution according to the topic of the talk as well as the presence of young (i.e., < 45 years) speakers. Data were analyzed using descriptive statistics.

RESULTS

During the last 10 years, a total of 498 plenary talks were found. Of those, 260 (52.2%), 211 (42.4%), and 27 (5.4%) discussed PCNL, fURS, or both, respectively. PCNL was more frequently discussed at the beginning and the end of the study period. Mean [SD] number of talks per speaker was higher for PCNL (2.9 [3.4] vs 1.6 [1.4], p < 0.001), meaning that a wider variety of speakers was invited to give fURS talks. Speakers discussing fURS were younger (median [interquartile range, IQR] age 48 [44-56] vs 52 [47-60] years, p < 0.001), and a higher proportion of young speakers was observed in the fURS group (26% vs 15% p < 0.001). PCNL speakers were more commonly discussing fURS than fURS speakers discussing PCNL (23% vs 17%, p = 0.43).

CONCLUSIONS

We found a wider variety of speakers at fURS plenary sessions as compared to PCNL ones. It is easier and quicker to become an internationally recognized expert in the field of fURS rather than PCNL. PCNL speakers were able to master fURS more frequently than the other way around.

Factors associated with complications after percutaneous nephrolithotomy: an analysis of 1,066 cases

OBJECTIVE

The aim of this study was to identify predictive factors for complications after percutaneous nephrolithotomy.

METHODS

We prospectively analyzed patients who underwent percutaneous nephrolithotomy from June 2011 to October 2018. The association of preoperative and intraoperative factors with the presence of complications was assessed using univariate and multivariate analyses. The significance level was set at p<0.05.

RESULTS

A total of 1,066 surgeries were evaluated, and the overall complication rate was 14.9%. In all, 105 (9.8%) surgeries were performed in the prone position, and 961 (90.2%) were performed in the supine position. Univariate analysis demonstrated that surgical position, upper pole puncture, surgical time, number of tracts, and Guys Stone Score were associated with complications. In multivariate analyses, prone position (odds ratio [OR] 2.10; p=0.003), surgical time ≥90 min (OR 1.76; p=0.014), upper pole puncture (OR 2.48; p<0.001), and Guys Stone Score 3 or 4 (OR 1.90; p=0.033) were independent predictive factors for complications after percutaneous nephrolithotomy.

CONCLUSION

Performing percutaneous nephrolithotomy in the supine position, in under 90 min, and avoiding upper pole punctures may reduce complications during the treatment of large kidney stones.

Propensity score-matched analysis comparing retrograde intrarenal surgery with percutaneous nephrolithotomy in anomalous kidneys

BACKGROUND

Endourologic interventions for urolithiasis in patients with anomalous kidneys can be challenging, and comparisons between these interventions are not well studied. We aim to compare the safety, outcomes and complications of retrograde intrarenal surgery (RIRS) versus percutaneous nephrolithotomy (PCNL) in patients with urolithiasis in anomalous kidneys.

METHODS

A propensity score-matched pair analysis (PSM) was performed on pooled patient data from 20 centers. 569 patients with anomalous kidneys (horseshoe kidney [HSK], ectopic kidney, malrotated kidney) and urolithiasis who received either PCNL or RIRS as the primary modality of intervention from 2010 to 2020 were analyzed. Patients were matched based on calculated propensity scores by a regression model using age, sex, comorbidities, stone size, and renal anomaly type as co-variates. Multivariate logistic regression of factors (mode of treatment [PCNL or RIRS], comorbidities, stone size) and their effects on outcomes of stone-free rate (SFR), need to abandon surgery due to intraoperative difficulty, postoperative hematuria and sepsis and were analyzed when applicable.

RESULTS

After PSM, there were a total of 127 pairs in each group. Overall, PCNL conferred a higher SFR compared to RIRS (OR=3.69, 95% CI 1.91-7.46, P<0.001), particularly in HSK (OR=3.33, 95% CI 1.22-9.99, P=0.023), and ectopic kidneys (OR=18.10, 95% CI 3.62-147.63, P=0.002), with no significant difference in malrotated kidneys. There was no significant difference in postoperative sepsis observed. Surgery was abandoned more often in RIRS than PCNL (6.3% vs. 0%, P=0.014). Although PSM provides a robust analysis due to baseline differences in the unmatched cohorts, this study was limited by an inevitable degree of selection bias.

CONCLUSIONS

While both modalities are safe and efficacious, PCNL yields better SFR than RIRS in patients with anomalous kidneys, with no difference in postoperative sepsis rates. Patients may benefit from personalized management best carried out in high volume endourology centers.

International Alliance of Urolithiasis (IAU) Guideline on percutaneous nephrolithotomy

The International Alliance of Urolithiasis (IAU) would like to release the latest guideline on percutaneous nephrolithotomy (PCNL) and to provide a clinical framework for surgeons performing PCNLs. These recommendations were collected and appraised from a systematic review and assessment of the literature covering all aspects of PCNLs from the PubMed database between January 1, 1976, and July 31, 2021. Each generated recommendation was graded using a modified GRADE methodology. The quality of the evidence was graded using a classification system modified from the Oxford Center for Evidence-Based Medicine Levels of Evidence. Forty-seven recommendations were summarized and graded, which covered the following issues, indications and contraindications, stone complexity evaluation, preoperative imaging, antibiotic strategy, management of antithrombotic therapy, anesthesia, position, puncture, tracts, dilation, lithotripsy, intraoperative evaluation of residual stones, exit strategy, postoperative imaging and stone-free status evaluation, complications. The present guideline on PCNL was the first in the IAU series of urolithiasis management guidelines. The recommendations, tips and tricks across the PCNL procedures would provide adequate guidance for urologists performing PCNLs to ensure safety and efficiency in PCNLs.

Presence of a Novel Anatomical Structure May Cause Bleeding When Using the Calyx Access in Mini-Percutaneous Nephrolithotomy

Background

Fused renal pyramid (FRP) is a kidney anatomical structure which was first identified by us. The vascular anatomy of FRP exhibits different from that of the normal renal pyramid (NRP), manifested by the distribution of the ectopic interlobar arteries in FRP. In this study, we analyzed the effect of FRPs on bleeding when using calyx access in mini-percutaneous nephrolithotomy (PCNL).

Patients and Methods

Overall, 633 patients who underwent ultrasound-guided single-tract mini-PCNL were divided into two groups according to the puncture method used: in group A, puncture was performed through the axial direction of the renal calyx, the line from the apex of the fornix to the center of the neck plane under B-mode ultrasound guidance; and in group B, Doppler ultrasound-guided axillary puncture through calyces corresponding to NRPs when the plane of renal column blood vessels on both sides was selected or calyx puncture through the hypovascular area of the FRPs. Relevant demographic and clinical data were retrospectively analyzed.

Results

The two groups exhibited similar baseline characteristics. No significant differences were found in hemoglobin reduction, puncture site, tract size, postoperative creatinine level, or stone-free rate between the two groups (P > 0.05). Blood transfusion and embolization rates in group B were significantly lower than those in group A (P = 0.03 and 0.045, respectively). No differences were found between the two groups in terms of persistent pain, hydrothorax, fever, subcapsular hematoma, and urosepsis (P > 0.05). The overall complication rate was not significantly different between the two groups (P = 0.505).

Conclusions

FRP is a non-negligible anatomical structure that may cause hemorrhage when using calyx access. Doppler ultrasound can identify ectopic blood vessels in FRPs to reduce bleeding during calyx access in mini-PCNL procedures.

Intrarenal pressures during percutaneous nephrolithotomy: a porcine kidney model

BACKGROUND

Increased intrarenal pressure during endoscopic lithotripsy is associated with increased adverse outcomes. The objective of this study was to evaluate the effect of various devices on IRP during percutaneous intrarenal surgery in ex vivo porcine kidney models.

METHODS

Whole intact porcine urinary tracts were harvested. Intrarenal pressure was measured using cystometrometry software. Intrarenal pressure during PCNL was recorded using variations of percutaneous access sheath size, irrigation height of 100 cm and 60 cm, use of a ureteric catheter and use of suction. The primary outcome was absolute IRP measurements. Secondary outcomes were comparisons of IRP between techniques.

RESULTS

Using a 30 Fr vs 26 Fr access sheath and 26 Fr nephroscope the mean pressure at an irrigation height of 60 cm was significantly lower than 100 cm (p = 0.0013 vs p < 0.0001, respectively). Pressure's during mini-PCNL were significantly higher than conventional PCNL in all variations. Using the 16.5 Fr access sheath and 12 Fr nephroscope produced a significantly lower pressure at a 60 cm irrigation height than 100 cm (p = 0.0010). IRP was significantly lower with a ureteric catheter in place vs no ureteric catheter at 100 cm (p = 0.0015) and at 60 cm (p = 0.0040).

CONCLUSIONS

Using standard PCNL tract sizes intrarenal pressure varied significantly depending on the height of the irrigation fluid. Mini-PCNL is at higher risk of pathological pressure, however, the use of a ureteric catheter significantly decreased pressure. To maintain safe IRP during PCNL urologists should be aware of these significant variations.

Impact of Trifecta definition on rates and predictors of "successful" robotic partial nephrectomy for localized renal masses: results from the Surface-Intermediate-Base Margin Score International Consortium

BACKGROUND

Over the years, five different Trifecta score definitions have been proposed to optimize the framing of "success" in partial nephrectomy (PN) field. However, such classifications rely on different metrics. The aim of the present study was to explore how the success rate of robotic PN, as well as its drivers, vary according to the currently available definitions of Trifecta.

METHODS

Data from consecutive patients with cT1-2N0M0 renal masses treated with robotic PN at 16 referral centers from September 2014 to March 2015 were prospectively collected. Trifecta rate was defined for each of the currently available definitions. Multivariable logistic regression analysis was used to evaluate possible predictors of "Trifecta failure" according to the different adopted formulation.

RESULTS

Overall, 289 patients met the inclusion criteria. Among the definitions, Trifecta rates ranged between 66.4% and 85.9%. Multivariable analysis showed that predictors for "Trifecta failure" were mainly tumor-related (i.e. tumor's nephrometry) for those Trifecta scores relying on WIT as a surrogate metric for postoperative renal function deterioration (definitions 1,2), while mainly surgery-related (i.e. ischemia time and excision strategy) for those including the percentage change in postoperative eGFR as the functional cornerstone of Trifecta (definitions 3-5).

CONCLUSIONS

There was large variability in rates and predictors of "unsuccessful PN" when using different Trifecta scores. Further research is needed to improve the value of the Trifecta metrics, integrating them into routine patient counseling and standardized assessment of surgical quality across institutions.

Can We Identify Patients in Danger of Complications in Retrograde Intrarenal Surgery?-A Retrospective Risk Factors Analysis

Retrograde intrarenal surgery (RIRS) is an innovative and effective method of kidney stones treatment, as it had great influence on the development of endoscopy in urology. The increasing prevalence of urolithiasis together with the rapid development of endourology leads to a rise in the number of procedures related to the disease. Flexible ureteroscopy is constantly being improved, especially regarding the effectiveness and safety of the procedure. The purpose of this study is to evaluate intraoperative and early post-operative complications of RIRS in the treatment of kidney stones. A retrospective analysis of medical records was performed. A series was comprised of 207 consecutive operations performed from 2017 to 2020. Complications occurred in 19.3% (n = 40) of patients. Occurrence according to the Clavien-Dindo scale was: 11.1% for grade I, 5.8% for grade II and 2.4% for grade IV. Infectious complications included SIRS (5.3%, n = 11) and sepsis (2.4%, n = 5). Statistical analysis revealed a correlation between acute post-operative infections and positive midstream urine culture, history of chronic or recurrent urinary tract infections, and increased body mass index (BMI). Furthermore, a significant correlation was observed between pain requiring the use of opioids with BMI over 25. Consequently, history of urinary tract infections, positive pre-operative urine culture, and increased BMI are considered risk factors and require appropriate management.