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This review addresses the management of urolithiasis in renal transplant recipients, a notably vulnerable group due to the unique anatomical and physiological alterations of the transplanted organ. The prevalence of nephrolithiasis in these patients varies between 0.1% and 6.3%, with a significant impact on graft longevity and function. Surgical access complications due to the renal graft's position on the iliac vessels and the variety of urinary anastomoses complicate the treatment approaches. This study evaluates the effectiveness and outcomes of percutaneous nephrolithotomy (PCNL) and ureteroscopy (URS), two primary minimally invasive strategies for managing graft stones. Through a narrative review using the PubMed and EMBASE databases, it was found that PCNL offers high stone-free rates especially beneficial for large stones, whereas URS provides a less invasive option with a lower risk of complications for small stones. Both techniques require tailored approaches based on stone composition-mostly calcium oxalate-and specific patient anatomical factors. This review underscores the importance of early diagnosis, appropriate treatment selection, and continuous post-treatment monitoring to mitigate risks and promote long-term renal function in transplant recipients.

Background: An accurate estimation of the stone burden is the key factor for predicting retrograde intra-renal surgical outcomes. Volumetric calculations better stratify stone burden than linear measurements. We developed a free software to assess the stone volume and estimate the lithotrity duration according to 3D-segmented stone volumes, namely the Kidney Stone Calculator (KSC). The present study aimed to validate the KSC's reproducibility in clinical cases evaluating its inter-observer and intra-observer correlations., Methods: Fifty patients that harbored renal stones were retrospectively selected from a prospective cohort. For each patient, three urologists with different experience levels in stone management made five measurements of the stone volume on non-contrast-enhanced computed tomography (NCCT) images using the KSC., Results: the overall inter-observer correlation (Kendall's concordance coefficient) was 0.99 ( p < 0.0001). All three paired analyses of the inter-observer reproducibility were superior to 0.8. The intra-observer variation coefficients varied from 4% to 6%, and Kendall's intra-observer concordance coefficient was found to be superior to 0.98 ( p < 0.0001) for each participant. Subgroup analyses showed that the segmentation of complex stones seems to be less reproductible., Conclusions: The Kidney Stone Calculator is a reliable tool for the stone burden estimation. Its extension for calculating the lithotrity duration is of major interest and could help the practitioner in surgical planning., Competing Interests: The authors declare that they have no conflicts of interest to disclose other than the following: Olivier Traxer is a consultant for the Boston Scientific Corporation, Coloplast, Quanta System, Rocamed, Wolf, Court Medical, B-Braun, and IPG. Steeve Doizi is a consultant for the Boston Scientific Corporation and Coloplast. Frederic Panthier is a consultant for Dornier.

Introduction: Thulium lasers (TLs), namely the Thulium fiber laser (TFL) and the Thulium:YAG (Tm:YAG), are being increasingly adopted for the conservative treatment of upper urinary tract urothelial carcinoma (UTUC). However, to date, the real clinical impact of TLs on UTUC management remains not well-characterized. We performed a review of the literature to summarize the current evidence on TLs for UTUC treatment., Materials and Methods: We performed a systematic review in January 2023 using the Embase and Medline online databases, according to the PRISMA recommendations and using the PICO criteria. Outcomes of interest were: (i) to assess the safety and feasibility of TLs in the treatment of UTUC, and (ii) to evaluate the oncological outcomes in terms of tumor recurrence and conservative treatment failure. Moreover, we described TL characteristics and its interaction with soft tissue., Results: a total of 458 articles were screened, and six full texts including 273 patients were identified. All the included studies were retrospective series. Mean patient age ranged from 66 to 73 years. The indication of a conservative treatment was elective and imperative in 21.7-85% and 15-76% of cases, respectively. Laser power settings varied from 5 to 50 W. No intraoperative complications were reported, and all the procedures were successfully performed. The tumor recurrence rate was 17.7-44%, and the indication to radical nephroureterectomy was 3.7-44% during a follow-up of 6-50 months. Most of the postoperative complications were mild and transient, and ureteral strictures were reported in two studies. Major limitations were the retrospective nature of the studies, the small sample sizes, and the short follow-up., Conclusions: TL is an effective and safe technology for endoscopic UTUC treatment. However, current available literature lacks prospective and multicentric studies with large population sizes and long-term follow-up.

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.

(1) Introduction: To evaluate the feasibility of measuring the intrapelvic pressure (IPP) during flexible ureterorenoscopy (f-URS) with a PressureWire and to optimize safety by assessing IPP during surgery. (2) Methods: Patients undergoing f-URS for different treatments were recruited. A PressureWire (0.014", St. Jude Medical, Little Canada, MN, USA) was placed into the renal cavities to measure IPP. Gravity irrigation at 40 cmH 2 O over the patient and a hand-assisted irrigation system were used. Pressures were monitored in real time and recorded for analysis. Fluid balance and postoperative urinary tract infection (UTI) were documented. (3) Results: Twenty patients undergoing f-URS were included with successful IPP monitoring. The median baseline IPP was 13.6 (6.8-47.6) cmH 2 O. After the placement of the UAS, the median IPP was 17 (8-44.6) cmH 2 O. With irrigation pressure set at 40 cmH 2 O without forced irrigation, the median IPP was 34 (19-81.6) cmH 2 O. Median IPP during laser lithotripsy, with and without the use of on-demand forced irrigation, was 61.2 (27.2-149.5) cmH 2 O. The maximum pressure peaks recorded during forced irrigation ranged from 54.4 to 236.6 cmH 2 O. After the surgery, 3 patients (15%) presented UTI; 2 of them had a positive preoperative urine culture, previously treated, and a positive fluid balance observed after the surgery. (4) Conclusion: Based on our experience, continuous monitoring of IPP with a wire is easy to reproduce, effective, and safe. In addition, it allows us to identify and avoid high IPPs, which may affect surgery-related complications.

Background: Endocorporeal laser lithotripsy (EL) during flexible ureteroscopy (URS-f) often uses "dusting" settings with "painting" technique. The displacement velocity of the laser fiber (LF) at the stone surface remains unknown and could improve EL's ablation rates. This in vitro study aimed to define the optimal displacement velocity (ODV) for both holmium:yttrium-aluminium-garnet (Ho:YAG) and thulium fiber laser (Tm-Fiber)., Methods: A 50W-TFL (IRE Polus ® , Moscow, Russia) and a 30W-MH1-Ho:YAG laser (Rocamed ® , Signes, Provence-Alpes-Côte d'Azur, France), were used with 272 µm-Core-Diameter LF (Sureflex, Boston Scientific © , San Jose, CA, USA), comparing three TFL modes, "fine dusting" (FD: 0.05-0.15 J/100-600 Hz); "dusting" (D: 0.5 J/30-60 Hz); "fragmentation" (Fr: 1 J/15-30 Hz) and two Ho:YAG modes (D: 0.5 J/20 Hz, Fr: 1 J/15 Hz). An experimental setup consisting of immerged cubes of calcium oxalate monohydrate (COM) stone phantoms (Begostone Plus, Bego © , Lincoln, RI, USA) was used with a 2 s' laser operation time. LF were in contact with the stones, static or with a displacement of 5, 10 or 20 mm. Experiments were repeated four times. Stones were dried and µ-scanned. Ablation volumes (mm 3 ) were measured by 3D-segmentation., Results: ODV was higher in dusting compared to fragmentation mode during Ho:YAG lithotripsy (10 mm/s vs. 5 mm/s, respectively). With Tm-Fiber, dusting and fragmentation OVDs were similar (5 mm/s). Tm-Fiber ODV was lower than Ho:YAGs in dusting settings (5 mm/s vs. 10 mm/s, respectively). Without LF displacement, ablation volumes were at least two-fold higher with Tm-Fiber compared to Ho:YAG. Despite the LF-DV, we report a 1.5 to 5-fold higher ablation volume with Tm-Fiber compared to Ho:YAG., Conclusions: In dusting mode, the ODV Tm-Fiber is lower compared to ODV Ho:YAG , translating to a potential easier Tm-Fiber utilization for "painting" dusting technique. The ODV determinants remain unknown. Dynamic ablation volumes are higher to static ones, regardless of the laser source, settings or LF displacement velocity.

Objectives: To compare the risk of laser fiber fracture between Ho:YAG laser and Thulium Fiber Laser (TFL) with different laser fiber diameters, laser settings, and fiber bending radii., Methods: Lengths of 200, 272, and 365 μm single use fibers were used with a 30 W Ho:YAG laser and a 50 W Super Pulsed TFL. Laser fibers of 150 µm length were also tested with the TFL only. Five different increasingly smaller bend radii were tested: 1, 0.9, 0.75, 0.6, and 0.45 cm. A total of 13 different laser settings were tested for the Ho:YAG laser: six fragmentation settings with a short pulse duration, and seven dusting settings with a long pulse duration. A total of 33 different laser settings were tested for the TFL. Three laser settings were common two both lasers: 0.5 J × 12 Hz, 0.8 J × 8 Hz, 2 J × 3 Hz. The laser was activated for 5 min or until fiber fracture. Each measurement was performed ten times., Results: While fiber failures occurred with all fiber diameters with Ho:YAG laser, none were reported with TFL. Identified risk factors of fiber fracture with the Ho:YAG laser were short pulse and high energy for the 365 µm fibers ( p = 0.041), but not for the 200 and 272 µm fibers ( p = 1 and p = 0.43, respectively). High frequency was not a risk factor of fiber fracture. Fiber diameter also seemed to be a risk factor of fracture. The 200 µm fibers broke more frequently than the 272 and 365 µm ones ( p = 0.039). There was a trend for a higher number of fractures with the 365 µm fibers compared to the 272 µm ones, these occurring at a larger bend radius, but this difference was not significant., Conclusion: TFL appears to be a safer laser regarding the risk of fiber fracture than Ho:YAG when used with fibers in a deflected position.