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Background and objectives: Renal stones are widespread, with a lifetime prevalence of 10% in adults. Flexible ureteroscopy enables urologists to treat lower calyx stones or even complex renal stones through the natural orifice and achieve an acceptable stone-free rate. Hence, we analyzed the effectiveness and safety of FURS versus PCNL in treating renal stones between 20 and 40 mm in diameter. Materials and methods: We retrospectively analyzed 250 consecutive patients with large renal solitary stones (stone burden between 2 and 4 cm) from 1 January 2019 to 31 December 2020. The patients were divided into two groups: group 1 (125 patients), in which the patients were treated by a retrograde flexible ureteroscopic approach, and group 2 (125 patients), in which we used percutaneous nephrolithotomy. Stone characteristics and anatomical data were observed based on the computed tomography (CT) and/or KUB (Kidney-ureter-Bladder) radiography imaging archive. Results: The mean stone burden was 26.38 ± 4.453 mm in group 1 and 29.44 ± 4.817 mm in group 2. The stone-free rate after the first ureteroscopy was higher for the PNL(percutaneous nephrolithotomy) group (90.4%) than the F-URS group (68%). After two sessions of ureteroscopy, the SFR was 88.8% in the first group, and after three procedures, the SFR rose to 95.2%. The overall complication rate was higher in group 1 than in group 2 (18.4% vs. 16.8%), but without statistical relevance (p > 0.5). Furthermore, we encountered more grade III and IV complications in the PNL group (8.8% vs. 4.8%, p < 0.05). Conclusion: Flexible ureteroscopy proves to be efficient in treating renal stones over 2 cm. However, the patients must be informed that more than one procedure might be necessary to overcome the entire stone burden. Full article

Backgound: The composition of stones formed in the urinary tract plays an important role in their management over time. The most common imaging method for the non-invasive evaluation of urinary stones is radiography and computed tomography (CT). However, CT is not very sensitive, and cannot differentiate between all critical stone types. In this study, we propose the application, and evaluate the potential, of a multi-modal (or multi-contrast) X-ray imaging technique called speckle-based imaging (SBI) to differentiate between various types of urinary stones. Methods: Three different stone samples were extracted from animal and human urinary tracts and examined in a laboratory-based speckle tracking setup. The results were discussed based on an X-ray diffraction analysis and a comparison with X-ray microtomography and grating-based interferometry. Results: The stones were classified through compositional analysis by X-ray diffraction. The multi-contrast images obtained using the SBI method provided detailed information about the composition of various urinary stone types, and could differentiate between them. X-ray SBI could provide highly sensitive and high-resolution characterizations of different urinary stones in the radiography mode, comparable to those by grating interferometry. Conclusions: This investigation demonstrated the capability of the SBI technique for the non-invasive classification of urinary stones through radiography in a simple and cost-effective laboratory setting. This opens the possibility for further studies concerning full-field in vivo SBI for the clinical imaging of urinary stones. Full article