Research Appraisals
Evidence-based critical appraisals of the latest medical research, systematically evaluated using Oxford CEBM methodology.
Showing 5 appraisals
Urolithiasis
A validated custom pipeline for three-dimensional kidney stone renderings to create an open access repository
Three-dimensional (3D) rendering of urologic pathology plays an important role in simulation-based education, surgical training, and computer vision research; however, a standardized, open-access repository of high-fidelity kidney stone models stratified by chemical composition is lacking. We developed and validated a reproducible photogrammetry-based pipeline to generate realistic 3D kidney stone renderings. Chemically characterized human stones composed of calcium oxalate monohydrate (COM) (n = 11), uric acid (UA) (n = 5), cystine (n = 4), magnesium ammonium phosphate hexahydrate/carbonate apatite (MAPH/CA) (n = 2), and calcium hydrogen phosphate dihydrate (CHPD) (n = 3) were photographed using a custom-built rotating stage and dual fixed 4 K cameras. Rendered models were sent to 25 endourologists using a 5-point Likert-scale survey assessing geometric and surface texture fidelity. Successful 3D renderings were obtained for 8/11 COM stones, 5/5 UA stones, 2/2 MAPH/CA fragments, and 3/3 CHPD fragments, while all cystine stones failed to render. Across stone types, mean fidelity scores were highest for UA and COM stones (mean 3.8-3.9), intermediate for calcium phosphate stones (mean 3.6-3.8), and lowest for struvite stones (mean 3.0-3.3). Geometry scores were higher than texture scores overall, though this difference was not significant. Significant differences in geometric fidelity were observed across stone compositions (χ² = 9.30, p = 0.026). Inter-rater reliability was poor for individual evaluators (ICC = 0.10) but moderate for aggregated mean ratings (ICC = 0.67). This validated workflow enables the creation of generally realistic, open-access 3D kidney stone models (github.com/uro-glidar/3d-rendering-diverse-stones) for simulation, education, and future machine learning applications in endourology.
21 June 2026
Read appraisal →BMC urology
Comparison of suction and standard ureteral access sheath versus sheathless flexible ureteroscopy in management of upper ureteral and renal calculi
PURPOSE: Comparative effectiveness of suction versus traditional ureteral access sheath (UAS) remains an area of ongoing research. We aim to compare the outcomes of retrograde intrarenal surgery (RIRS) with suction and standard UAS versus without UAS in the management of renal and upper ureteric stones, with a specific focus on operative efficiency, stone-free rates, and postoperative complications. METHODS: This study was conducted between October 2023 and January 2025, including 90 patients with renal stones ≤ 3 cm and upper ureteric stones ≤ 1.5 cm. Patients were divided into three groups by random Allocation Software (version 2): Group A1 (standard UAS, n = 30), Group A2 (suction UAS, n = 30), and Group B (no UAS, n = 30). Operative time, vision quality, stone clearance, complications, and hospital stay were assessed. RESULTS: Group A2 had the shortest mean operative time (70.1 ± 10.3 min) with significantly better vision compared to Group A1 (114.3 ± 27.0 min) and Group B (125.0 ± 28.01 min) (p < 0.001). Residual stone rates were lowest in Group A2 (3.3%) compared to Group A1 (10.0%) and Group B (26.7%) (p = 0.035). The need for a second procedure was significantly higher in Group B (26.7%) compared to Group A1 (10.0%) and absent in Group A2 (p = 0.002). Hospital stay was significantly shorter in Group A2 compared to Group A1 and Group B (p = 0.005). Fever incidence (Clavien Grade II) was significantly higher in Group B (23.3%) compared to Group A1 (16.7%) and absent in Group A2 (p = 0.005). CONCLUSION: Suction ureteral access sheaths in flexible ureteroscopic lithotripsy for renal stones ≤ 3 cm and upper ureteric stones ≤ 1.5 cm was associated with improved stone clearance, reduced operative time and hospital stay, provide better endoscopic vision, minimized infectious complications and need for second procedure, compared to standard UAS or no sheath. However, outcomes may be influenced by surgeon experience and familiarity with suction-assisted systems. Prospective multicenter studies with larger sample sizes and varying surgeon experience levels are recommended.
27 May 2026
Read appraisal →World journal of urology
Supine mini-PCNL using pneumatic lithotripsy for pediatric renal stones: safety and efficacy in low-income countries
BACKGROUND: Mini-percutaneous nephrolithotomy (mini-PCNL) is an effective surgical technique for pediatric renal stones. However, data comparing different lithotripsy modalities in this population are limited. PURPOSE: To compare the efficacy, safety, and acute renal parenchymal impact of pneumatic lithotripsy versus Holmium: YAG (Ho: YAG) laser dusting during supine mini-percutaneous nephrolithotomy (mini-PCNL) in pediatric patients. PATIENTS AND METHODS: A double-masked, randomized clinical trial was conducted between March 2023 and October 2024. A total of 104 pediatric patients (ages 3-10 years) with solitary renal stones (10-25 mm) were randomized into two groups: Group 1 (n = 53) underwent mini-PCNL using a pneumatic lithotripter, and Group 2 (n = 51) underwent mini-PCNL using Ho: YAG laser dusting. Primary outcomes included operative time, stone-free rate (SFR), complications (Clavien-Dindo), and biochemical markers of renal injury, including Kidney Injury Molecule-1 (KIM-1) and albumin/creatinine (A/C) ratio. RESULTS: Pneumatic lithotripsy demonstrated significantly shorter mean operative times (59.5 vs. 67.6 min, p = 0.007) and lithotripsy times (p < 0.001) compared to the laser group. The stone-free rates were comparable between the pneumatic and laser groups (92.45% vs. 94.1%, p > 0.05). Group 1 (pneumatic) had a significantly shorter hospital stay (2.2 vs. 2.6 days, p = 0.004). While both groups showed postoperative elevations in injury markers, the laser group exhibited significantly higher and more sustained levels of urinary KIM-1 and A/C ratios, as well as higher postoperative RBC counts in nephrostomy samples (p < 0.05). No major complications or perforations occurred in either group. CONCLUSIONS: Pneumatic lithotripsy is a highly effective and safe alternative to laser lithotripsy for pediatric mini-PCNL. It offers comparable operative efficiency, reduced hospital stays, and potentially lower acute tubular injury as evidenced by lower KIM-1 levels. Given its lower cost and comparable stone-free rates, pneumatic lithotripsy is a favorable option for managing pediatric renal stones in resource-conscious settings.
18 May 2026
Read appraisal →World journal of urology
Complications of thulium fiber laser lithotripsy: a systematic review and meta-analysis by the EAU-YAU endourology and urolithiasis working group
BACKGROUND: Thulium Fiber Laser (TFL) has emerged as a promising alternative to Holmium: YAG for lithotripsy, yet its safety profile remains fragmented across various trials. This study aims to synthesize available evidence to determine the pooled complication rates associated with TFL lithotripsy . METHODS: A systematic review was conducted following PRISMA guidelines. We searched PubMed, Cochrane CENTRAL, and ClinicalTrials.gov for studies reporting complications of TFL in adult patients with urolithiasis. The primary outcome was the overall complication rate. Secondary outcomes included Clavien-Dindo grading, specific adverse events (fever, sepsis, injury), and stone-free rate (SFR). A random-effects meta-analysis was performed using the Freeman-Tukey double-arcsine transformation. RESULTS: Thirty-eight studies involving 3,329 patients were included. The pooled overall complication rate was 10.42% (95% CI: 8.01%-13.10%; I²=81.9%). Major complications (Clavien-Dindo III-V) were rare, with a pooled rate of 1.19% (95% CI: 0.68%-1.84%). Specific event rates included fever (2.45%), ureteral injury (1.37%), bleeding (1.07%), urosepsis (0.77%), ureteral strictures (0.70) and acute pyelonephritis (0.59%). Meta-regression identified operative time as a significant predictor of complications (p = 0.041), whereas stone size was not (p = 0.358). Subgroup analysis showed higher complication rates in pure renal stone treatments (13.83%) compared to ureteral stones (10.64%). The pooled Stone-Free Rate (SFR) was 87.61% (95% CI: 83.61%-91.12%). CONCLUSION: Thulium Fiber Laser lithotripsy demonstrates a pretty favorable safety profile with a very low incidence of high-grade complications (< 1.2%) and high efficacy.
14 May 2026
Read appraisal →World journal of urology
Clinical and procedural factors influencing ureteral stent dwell time and removal methods after endourological procedures: a systematic review.
INTRODUCTION: Ureteral stents are routinely used following endourological procedures to ensure adequate drainage and prevent obstruction. However, stent-related morbidity remains common, and optimal stent dwell time and removal methods are not well defined. This systematic review aimed to evaluate clinical and procedural factors influencing ureteral stent dwell time and the methods used for stent removal after endourological interventions. METHODS: A systematic review was conducted in accordance with PRISMA guidelines and registered on PROSPERO. MEDLINE and Embase were searched from inception to October 2025. Randomized controlled trials and comparative observational studies evaluating ureteral stent dwell time and/or removal methods in adults undergoing endourological procedures were included. Risk of bias was assessed using RoB 2 and ROBINS-I tools. RESULTS: Thirty-two studies encompassing 4,373 patients were included. Reported stent dwell times varied widely, most commonly ranging between 10 and 14 days in uncomplicated cases, with longer durations associated with increased rates of encrustation and removal difficulty. Removal techniques included rigid cystoscopy (48.7%), flexible cystoscopy (19.9%), extraction strings (23.5%), and device-assisted methods (7.9%). Less invasive approaches, particularly flexible cystoscopy and extraction-string removal, were consistently associated with reduced pain scores and improved patient comfort, although extraction strings carried a small risk of premature dislodgement. CONCLUSIONS: While practice patterns vary, the evidence suggests that a 10-14 day dwell time might be the optimal window to balance healing with the prevention of encrustation. Less invasive removal approaches, particularly flexible cystoscopy and extraction-string techniques, were generally associated with lower pain scores and high procedural success rates in selected patients. While these methods are safe and better tolerated, extraction strings carried a small, reproducible risk of premature dislodgement. High-quality prospective studies are needed to define determinant-based, individualized stent management strategies.
10 May 2026
Read appraisal →