International Alliance of Urolithiasis (IAU) Guideline on percutaneous nephrolithotomy

Consensus statement addressing controversies and guidelines on pediatric urolithiasis

PURPOSE

We aimed to investigate controversial pediatric urolithiasis issues systematically, integrating expert consensus and comprehensive guidelines reviews.

METHODS

Two semi-structured online focus group meetings were conducted to discuss the study's need and content, review current literature, and prepare the initial survey. Data were collected through surveys and focus group discussions. Existing guidelines were reviewed, and a second survey was conducted using the Delphi method to validate findings and facilitate consensus. The primary outcome measures investigated controversial issues, integrating expert consensus and guideline reviews.

RESULTS

Experts from 15 countries participated, including 20 with 16+ years of experience, 2 with 11-15 years, and 4 with 6-10 years. The initial survey identified nine main themes, emphasizing the need for standardized diagnostic and treatment protocols and tailored treatments. Inter-rater reliability was high, with controversies in treatment approaches (score 4.6, 92% agreement), follow-up protocols (score 4.8, 100% agreement), and diagnostic criteria (score 4.6, 92% agreement). The second survey underscored the critical need for consensus on identification, diagnostic criteria (score 4.6, 92% agreement), and standardized follow-up protocols (score 4.8, 100% agreement).

CONCLUSION

The importance of personalized treatment in pediatric urolithiasis is clear. Prioritizing low-radiation diagnostic tools, effectively managing residual stone fragments, and standardized follow-up protocols are crucial for improving patient outcomes. Integrating new technologies while ensuring safety and reliability is also essential. Harmonizing guidelines across regions can provide consistent and effective management. Future efforts should focus on collaborative research, specialized training, and the integration of new technologies in treatment protocols.

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.

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.

Design and internal validation of S.I.C.K.: a novel nomogram predicting infectious and hemorrhagic events after percutaneous nephrolithotomy

BACKGROUND

Hemorrhagic and infectious events represent severe complications after percutaneous nephrolithotomy (PCNLs). Existing nephrolithometric nomograms have been introduced but their reliability in predicting complications is debated. We present a newly designed nomogram with intention to predict hemorrhagic/infectious events after PCNLs.

METHODS

We conducted a multicentric prospective study on adult patients undergoing standard (24 Fr) or mini (18 Fr) PCNL. Dataset was derived from previous RCT, where patients have been assigned to mini-PCNL or standard-PCNL to treat renal stones up to 40 mm. Aim of the study was to identify preoperative risk factors for early postoperative infectious/hemorrhagic complications including fever, septic shock, transfusion or angioembolization.

RESULTS

A total of 1980 patients were finally included. 992 patients (50.1%) received mini-PCNL and 848 standard PCNL (49.9%). The overall SFR was 86.1% with a mean maximum stone diameter of 29 mm (SD 25.0-35.0). 178 patients (8.9%) had fever,14 (0.7%) urosepsis, 24 patients (1.2%) required transfusion and 18 (0.9%) angioembolization. The overall complication was (11.7%). After multivariable analysis, the included elements in the nomogram were age (P=0.041), BMI (P=0.018), maximum stone diameter (P<0.001), preoperative hemoglobin (P=0.005), type 1/2 diabetes (P=0.05), eGFR<30 (P=0.0032), hypertension (>135/85 mmHg, P=0.001), previous PCNL or pyelo/nephrolithotomy (P=0.0018), severe hydronephrosis (P=0.002). After internal validation, the AUC of the model was 0.73.

CONCLUSIONS

This is the first nomogram predicting infections and bleedings after PCNLs, it shows a good accuracy and can support clinicians in their patients' peri-operative workout and management.

Mini-percutaneous nephrolithotomy versus retrograde intrarenal surgery for the treatment of 10-20-mm kidney stones in patients with ileal conduit: a comparative study

BACKGROUND

Both mini-percutaneous nephrolithotomy (mPNL) and retrograde intrarenal surgery (RIRS) are two major strategies for the endourological management of kidney stones. In the current study, we aimed to compare the efficacy and safety of mPNL and RIRS for the treatment of 10-20 mm kidney stones in patients with ileal conduit.

METHODS

Patients with a history of bladder cancer and ileal conduit who had undergone mPNL or RIRS for unilateral kidney stones 10-20 mm in size between January 2015 and June 2022 were retrospectively included. Baseline characteristics and perioperative outcomes were analyzed and compared between mPNL and RIRS.

RESULTS

The failure rate of the initial surgery was 2.5% and 18.9% for mPNL and RIRS, respectively (P=0.025). In total, 39 and 30 patients were finally included in the mPNL and RIRS groups. One-session stone-free rate (SFR) was higher in the mPNL group than the RIRS group (97.4% vs. 66.7%, P=0.002). However, there was no statistically significant difference between the two groups with regard to operation time, postoperative hospitalization, complications according to Clavien-Dindo classification, as well as the change in hemoglobin, creatinine, procalcitonin, and pain Visual Analogue Scale Score before and after the surgery. Moreover, Results were consistent across subgroup analyses in patients stratified by years (2015-2018 and 2019-2022).

CONCLUSIONS

Both mPNL and RIRS were feasible and safe for the treatment of 10-20 mm kidney stones in patients with ileal conduit. However, mPNL achieved superior SFR outcomes with a similar incidence of complications, and it might be a sensible alternative for selected patients.

International Alliance of Urolithiasis Guideline on Shockwave Lithotripsy

Different international associations have proposed their own guidelines on urolithiasis. However, the focus is primarily on an overview of the principles of urolithiasis management rather than step-by-step technical details for the procedure. The International Alliance of Urolithiasis (IAU) is releasing a series of guidelines on the management of urolithiasis. The current guideline on shockwave lithotripsy (SWL) is the third in the IAU guidelines series and provides a clinical framework for urologists and technicians performing SWL. A total of 49 recommendations are summarized and graded, covering the following aspects: indications and contraindications; preoperative patient evaluation; preoperative medication; prestenting; intraoperative analgesia or anesthesia; intraoperative position; stone localization and monitoring; machine and energy settings; intraoperative lithotripsy strategies; auxiliary therapy following SWL; evaluation of stone clearance; complications; and quality of life. The recommendations, tips, and tricks regarding SWL procedures summarized here provide important and necessary guidance for urologists along with technicians performing SWL. PATIENT SUMMARY: For kidney and urinary stones of less than 20 mm in size, shockwave lithotripsy (SWL) is an approach in which the stone is treated with shockwaves applied to the skin, without the need for surgery. Our recommendations on technical aspects of the procedure provide guidance for urologists and technicians performing SWL.

Development and internal validation of a prediction model to evaluate the risk of severe hemorrhage following mini-percutaneous nephrolithotomy

PURPOSE

To develop a new prediction model for assessing the severe hemorrhage events in post mini-percutaneous nephrolithotomy (mini-PCNL) patients and internally validate it, thus to guide decision making in clinical practice.

METHODS

The patients who underwent mini-PCNL were retrospectively reviewed. Potential risk factors were included as prediction variables for multivariate logistic regression analysis to identify independent risk factors, and prediction model was constructed. The predictive ability of the model was evaluated using the Concordance index (C-index) and Brier score. Bootstrapping resampling technique was used to perform internal validation. The related packages in R were used to generate the web application based on the prediction model.

RESULTS

Multiple-tract was the strongest predictor of severe hemorrhage following mini-PCNL. Other risk factors were none or mild hydronephrosis, congenital anomalies of urinary system, urinary tract infection, operation time and stone peak Hounsfield unit. A prediction model was constructed to assess the probability of severe hemorrhage after mini-PCNL. The C-index and Brier score were 0.731 and 0.093, respectively after correcting for optimism, which signified the excellent discrimination and calibration.

CONCLUSION

A new prediction model was developed to estimate risk of severe hemorrhage after mini-PCNL. It had been internally validated with good discrimination and calibration. The prediction model might be beneficial for endourologists in surgical decision-making and risk aversion.

Retroperitoneal laparoscopic renorrhaphy for post-percutaneous nephrolithotomy hemorrhage: a case report

Percutaneous nephrolithotomy is the preferred treatment for large renal calculi; however, postoperative hemorrhage is a dangerous complication. The three main causes of hemorrhage after percutaneous nephrolithotomy are pseudoaneurysms, arteriovenous fistulas, and arterial lacerations. The preferred treatment for acute hemorrhage is superselective angioembolization. However, in a few cases, angiography reveals no abnormal findings pertaining to hemorrhage. We herein present a clinical case of a 48-year-old man who presented with multiple complex right renal calculi and was managed with percutaneous nephrolithotomy in the prone position. Massive hemorrhage occurred 6 days postoperatively, and renal angiography was immediately performed. However, while the bleeding was still occurring, no extravasation was observed on renal angiography. We performed retroperitoneal laparoscopic renorrhaphy, which successfully stopped the bleeding and consequently preserved the kidney. We suggest that retroperitoneal laparoscopic renorrhaphy can be effective in patients who have undergone failed renal arterial embolization or are reluctant to undergo renal arterial embolization.