Faculty Bibliography

BACKGROUND:The stricture-formation rate following ureteroscopy ranges from 0.5 to 5% and might amount to 24% in patients with impacted ureteral stones. The pathogenesis of ureteral stricture formation is not yet fully understood. It is likely that the patient and stone characteristics, as well as intervention factors, play a role in this process. In this systematic review, we aimed to determine the potential factors responsible for ureteral stricture formation in patients having impacted ureteral stones. METHODS:Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) criteria, we conducted systematic online research through PubMed and Web of Science without a time restriction, applying the keywords "ureteral stone", "ureteral calculus", "impacted stone", "ureteral stenosis", "ureteroscopic lithotripsy", "impacted calculus", and "ureteral strictures" singly or in combination. RESULTS:After eliminating non-eligible studies, we identified five articles on ureteral stricture formation following treatment of impacted ureteral stones. Ureteral perforation and/or mucosal damage appeared as key predictors of ureteral stricture following retrograde ureteroscopy (URS) for impacted ureteral stones. Besides ureteral perforation stone size, embedded stone fragments into the ureter during lithotripsy, failed URS, degree of hydronephrosis, nephrostomy tube or double-J stent (DJS)/ureter catheter insertion were also suggested factors leading to ureteral strictures. CONCLUSION/CONCLUSIONS:Ureteral perforation during surgery might be considered the main risk factor for ureteral stricture formation following retrograde ureteroscopic stone removal for impacted ureteral stones.

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.

INTRODUCTION/BACKGROUND:The aim of this systematic review and meta-analysis was to provide an updated comparison between the currently available minimally invasive approaches (PCNL, laparoscopic [LP] and robotic pyelolithotomy [RP]) for the management of large renal stones. EVIDENCE ACQUISITION/METHODS:An electronic search of the current literature was conducted through the Medline and NCBI PubMed, Embase, Scopus and Cochrane Collaboration Central Register of Controlled Clinical Trials databases in March 2021. Studies about minimally-invasive treatment for kidney stones were considered. Inclusion criteria were: studies evaluating patients with large renal calculi (≥2 cm); the comparison of at least two of the three approaches (PCNL, LP, RP), and reporting data suitable for meta-analysis evaluation. Patients with concomitant management for ureteropelvic junction obstruction (UPJ-O) were excluded. EVIDENCE SYNTHESIS/RESULTS:Overall, 17 reports were considered for qualitative and quantitative synthesis, for a total cohort of 1079 patients, of which 534 with PCNL, 525 treated with LP, and 20 with RP. Of those, 16 compared PCNL with LP, while only 1 study compared LP with RP. PCNL mean operative time was statistically significantly shorter than LP and RP while mean estimated blood loss was statistically significantly higher for PNCL. No statistically significant differences were recorded among the three surgical approaches. Finally, PCNL demonstrated slightly, albeit statistically significant lower stone free rate when compared with LP. CONCLUSIONS:PCNL, LP and RP may be safely and efficiently used to manage large renal stones. All three procedures showed reasonably low rate of complications with a satisfactory stone clearance rate.

PURPOSE/OBJECTIVE:To evaluate the decompression of the pelvicalyceal system between urologists and radiologists. METHODS:A survey was distributed to urologists and to radiologists comparing double-J stent (DJS), percutaneous nephrostomy (PN) and primary ureteroscopy (URS) for three clinical scenarios (1-febrile hydronephrosis; 2-obstruction and persistent pain; 3-obstruction and anuria) before and after reading literature The survey included perception on radiation dose, cost and quality of life (QoL). RESULTS:Response rate was 40% (366/915). 93% of radiologists believe that DJS offers a better QOL compared to 70.6% of urologists (p = 0.006). 28.4% of urologists consider PN to be more expensive compared to 8.9% of radiologists (p = 0.006). 75% of radiologists believe that radiation exposure is higher with DJS as opposed to 33.9% of urologists. There was not a difference in the decompression preference in the first scenario. After reading the literature, 28.6% of radiologists changed their opinion compared to 5.2% of urologists (p < 0.001). The change favored DJS. In the second scenario, responders preferred equally DJS and they did not change their opinion. In the third scenario, 41% of radiologists chose PN as opposed to 12.6% of urologists (p < 0.001). After reading the literature, 17.9% of radiologists changed their opinion compared to 17.9% of urologists (p < 0.001), in favor of DJS. Although the majority of urologists (63.4%) consistently perform primary URS, only 3, 37 and 21% preferred it for the first, second and third scenarios, respectively. CONCLUSION/CONCLUSIONS:The decision on the type of drainage of a stone-obstructing hydronephrosis should be individualized.

Percutaneous nephrolithotomy (PCNL) is frequently used as the first-line treatment of large and complex stones. The key point for successful complex stone removal with minimal risk of complications is to establish the most appropriate access route. Understanding the three-dimensional (3D) relationship of kidney stones and renal collecting systems is crucial for planning and creating an optimal access route. By using a 3D volume segmentation tool a more accurate approach to the renal collecting system and stone treatment could be planned. The objective of this study was assessing the impact of 3D software in getting the desired access.

(1) Background: New pulse modulation (PM) technologies in Holmium:YAG lasers are available for urinary stone treatment, but little is known about them. We aim to systematically evaluate the published evidence in terms of their lithotripsy performance. (2) Methods: A systematic electronic search was performed (MEDLINE, Scopus, and Cochrane databases). We included all relevant publications, including randomized controlled trials, non-randomized comparative and non-comparative studies, and in-vitro studies investigating Holmium:YAG lithotripsy performance employing any new PM. (3) Results: Initial search yielded 203 studies; 24 studies were included after selection: 15 in-vitro, 9 in-vivo. 10 In-vitro compared Moses with regular PM, 1 compared Quanta's, 1 Dornier MedTech's, 2 Moses with super Thulium Fiber Laser, and 1 compared Moses with Quanta PMs. Six out of seven comparative studies found a statistically significant difference in favor of new-generation PM technologies in terms of operative time and five out of six in fragmentation time; two studies evaluated retropulsion, both in favor of new-generation PM. There were no statistically significant differences regarding stone-free rate, lasing and operative time, and complications between Moses and regular PM when data were meta-analyzed. (4) Conclusions: Moses PM seems to have better lithotripsy performance than regular modes in in-vitro studies, but there are still some doubts about its in-vivo results. Little is known about the other PMs. Although some results favor Quanta PMs, further studies are needed.

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.

OBJECTIVE:To analyze the trends and outcomes of retrograde intrarenal surgery for treatment of urolithiasis in anomalous kidneys in a large international multicenter series. MATERIALS AND METHODS:We designed a multicentric retrospective study. Nineteen high-volume centers worldwide were included. Pre-, peri- and postoperative data were collected, and a subgroup analysis was performed according to renal anomaly. RESULTS:We analyzed 414 procedures: 119 (28.7%) were horseshoe kidneys, 102 (24.6%) pelvic ectopic kidneys, 69 (16.7%) malrotated kidneys and 50 (12.1%) diverticular calculus. The average size (SD) of the stone was 13.9 (±6) millimeters and 193 (46.6%) patients had a pre-operative stent. In 249 cases (60.1%) a disposable scope was used. A UAS (ureteral access sheath) was used in 373 (90%) patients. A Holmium laser was used in 391 (94.4%) patients. The average (SD) operating time was 65.3 (±24.2) minutes. Hematuria, caliceal perforation and difficulty in stone localisation were mostly seen in diverticular stones and difficulty in UAS placement and lithotripsy in the cases of renal malrotation. The overall complication rate was 12%. Global stone-free rate was 79.2%. Residual fragments (RF) were significantly lesser in the pre-stented group (P <.05). Diverticular calculi was the group with more RF and needed ancillary procedures (P <.05). CONCLUSION:Retrograde intrarenal surgery in patients with anomalous kidneys is safe and effective with a high single-stage stone-free rate and low complication rate. There is a trend toward using smaller and disposable scopes and smaller UAS. Diverticular stones can still be challenging with higher rates of intraoperative hematuria, caliceal perforation and RF.

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.