Thulium fiber laser vs Ho:YAG in RIRS: a prospective randomized clinical trial assessing the efficacy of lasers and different fiber diameters (150 µm and 200 µm).

INTRODUCTION: The aims of the study: (1) to compare the Super Pulse Thulium Fiber Laser (SP TFL) and the holmium: yttrium-aluminium-garnet (Ho:YAG) lasers in retrograde intrarenal surgery (RIRS); (2) to compare the efficacy of SP TFL laser fibers of different diameters (150 µm and 200 µm). METHODS: A prospective randomized single-blinded trial was conducted. Patients with stones from 10 to 20 mm were randomly assigned RIRS in three groups: (1) SP TFL (NTO IRE-Polus, Russia) with fiber diameter of 150 µm; (2) SP TFL with 200-µm fiber; and (3) Ho:YAG (Lumenis, USA) with 200-µm fiber. RESULTS: Ninety-six patients with kidney stones were randomized to undergo RIRS with SP TFL using a 150-µm fiber (34 patients) and a 200-µm fiber (32 patients) and RIRS with Ho:YAG (30 patients). The median laser on time (LOT) in the 200-µm SP TFL group was 9.2 (6.2-14.6) min, in 150-µm SP TFL-11.4 (7.7-14.9) min (p = 0.390), in Ho:YAG-14.1 (10.8-18.1) min (p = 0.021). The total energy consumed in 200-µm SP TFL was 8.4 (5.8-15.2) kJ; 150-µm SP TFL - 10.8 (7.3-13.5) kJ (p = 0.626) and in Ho:YAG-15.2 (11.1-25.3) kJ (p = 0.005). CONCLUSIONS: Irrespective of the density, RIRS with SP TFL laser has proven to be both a safe and effective procedure. Whilst the introduction of smaller fibers may have the potential to reduce the duration of surgery, SP TFL results in a reduction in the LOT and total energy for stone ablation in RIRS compared with Ho:YAG.

Prospective Single-Center Study of SuperPulsed Thulium Fiber Laser in Retrograde Intrarenal Surgery: Initial Clinical Data.

INTRODUCTION: The objective of this study was to present our clinical experience of using the thulium fiber laser in retrograde intrarenal surgery (RIRS). METHODS: A prospective clinical study performed after the IRB approval (Sechenov University, Russia). Patients with stones <30 mm were treated with SuperPulsed thulium fiber laser (SP TFL) (NTO IRE-Polus, Russia) through a 200-µm-diameter fiber. Stone size, density, the duration of the operation, and laser on time (LOT) were measured. Based on the surgeon's feedback, retropulsion and intraoperative visibility were also assessed (Likert scale). Stone-free rates (SFRs) were assessed with a low-dose CT scan 90 days after the operation. RESULTS: Between January 2018 and December 2019, 153 patients (mean age 54 ± 2.8 years) underwent RIRS with SP TFL (mean stone density 1,020 ± 382 HU). Median stone volume was 279.6 (139.4-615.8) mm3. Median LOT was 2.8 (IQR 1.6-6.6) min with median total energy for stone ablation 4.0 (IQR 2.1-7.17) kJ, median ablation speed was 1.7 (1.0-2.8) mm3/s, median ablation efficacy was 13.3 (7.3-20.9) J/mm3, and energy consumption was 170.3 (59.7-743.3) J/s. Overall, the SFR (at 3 months) was 89%. The overall complication rate was 8.4%. Retropulsion was present in 23 (15.1%) patients. Visibility was estimated as optimal in most patients, with poor visibility reported in only 13 (8.5%) patients. CONCLUSION: The SP TFL is a safe and efficient tool in lithotripsy, irrespective of the stone type and density. Retropulsion is minimal and visibility is maintained with SP TFL. Nonetheless, further clinical studies are needed to ensure optimal comparison with conventional holmium:YAG lithotripsy.

Superpulse thulium fiber laser lithotripsy: an in vitro comparison of 200 µm and 150 µm laser fibers.

PURPOSE: To investigate the thermal effects, stone retropulsion and ablation rate of SuperPulse Thulium-fiber laser (SP TFL) with two different surgical fibers of 200 and 150 µm in diameter. METHODS: SP TFL (NTO IRE-Polus, Fryazino, Russia) performance with 200 and 150 µm fibers (NTO IRE-Polus, Fryazino, Russia) was evaluated. Before each test, the laser fiber was cleaved, and the power measurement was taken to verify the actual laser output power. To compare the laser fibers in well-controlled environments, a number of setups were used to assess retropulsion, ablation efficacy, fiber burnback, energy transmission, and safety. RESULTS: Power measurements performed before each test revealed a 4.7% power drop for a 200 µm fiber SP TFL (14.3 ± 0.5 W) and 7.3% power drop for a 150 µm fiber SP TFL (13.9 ± 0.5 W) versus the nominally indicated power (15.0 W). Retropulsion with the TFL was minimal and comparable between fibers. We found no clinically relevant temperature differences between SP TFL with either 200 or 150 µm fibers. The ablation efficacy tended to be comparable under most parameters. Yet, we did observe a decreased diameter of residual fragments after the ablation with a 150 µm fiber. CONCLUSION: The smaller fiber (150 µm) is not inferior to 200 µm fiber in terms of fiber burnback, retropulsion, safety, and ablation rate. Moreover, it has the potential to decrease the diameter of fragments during lithotripsy, which may facilitate dusting during RIRS.

Temperature changes during laser lithotripsy with Ho:YAG laser and novel Tm-fiber laser: a comparative in-vitro study.

AIM: The aim of this study was to compare the thermal effects of Ho:YAG and Tm-fiber lasers during lithotripsy in an in-vitro model via real-time temperature measurement. METHODS: We compared a Ho:YAG laser (pav up to 100 W, Lumenis, Yokneam, Israel) and a superpulse Tm-fiber laser (SP TFL, pav up to 40 W, NTO IRE-Polus, Fryazino, Russia), both equipped with 200 µm bare-ended fibers. The following settings were used: 0.2 J, 40 Hz (nominal pav 8 W). Power meter FieldMaxII-TO (Coherent, Santa Clara, CA, USA) was used to verify output laser power (pav). Each laser was fired for 60 s in two setups: (1) thermos-insulated (quasi-adiabatic) cuvette; (2) actively irrigated setup with precise flow control (irrigation rates 0, 10, 35 mL/min). RESULTS: Power measurements performed before the test revealed a 10% power drop in Ho:YAG (up to 7.2 ± 0.1 W) and 6.25% power drop in SP TFL (up to 7.5 ± 0.1). At the second step of our experiment, irrigation reduced the respective temperatures in the same manner for both lasers (e.g., at 35 mL/s SP TFL - 1.9 °C; for Ho:YAG laser - 2.8 °C at 60 s). CONCLUSION: SP TFL and Ho:YAG lasers are not different in terms of volume-averaged temperature increase when the same settings are used in both lasers. Local temperature rises may fluctuate to some degree and differ for the two lasers due to varying jet streaming caused by non-uniform heating of the aqueous medium by laser light.

Thulium-fiber laser for lithotripsy: first clinical experience in percutaneous nephrolithotomy.

PURPOSE: To evaluate the efficacy and safety of thulium-fiber laser (TFL) in laser lithotripsy during percutaneous nephrolithotomy (PCNL). METHODS: Patients with stones < 30 mm were prospectively recruited to undergo PCNL using TFL "FiberLase" (NTO IRE-Polus, Russia). Stone size, stone density, operative time, and "laser on" time (LOT) were recorded. Study included only cases managed with fragmentation. Stone-free rate and residual fragments were determined on postoperative computer tomography. Complications were classified using the Clavien-Dindo grade. Stone retropulsion and endoscopic visibility were assessed based on surgeons' feedback using a questionnaire. RESULTS: A total of 120 patients were included in the study with a mean age of 52 (± 1.8) years; of these 77 (56%) were males. Mean stone size was 12.5 (± 8.8) mm with a mean density of 1019 (± 375) HU. Mean operative time was 23.4 (± 17.9) min and mean LOT was 5.0 (± 5.7) min. Most used settings were of 0.8 J/25-30 W/31-38 Hz (fragmentation). The mean total energy for stone ablation was 3.6 (± 4.3) kJ. Overall stone-free rate was 85%. The overall complication rate was 17%. Surgeons reported stone retropulsion that interfered with surgery in 2 (1.7%) cases insignificant retropulsion was noted in 16 (10.8%) cases. Poor visualization was reported in three (2.5%) cases and minor difficulties with visibility in four (3.3%) cases. CONCLUSIONS: TFL is a safe and effective modality for lithotripsy during PCNL and results in minimal retropulsion.

Contrast-enhanced ultrasound (CEUS) as a follow-up method after the focal treatment of renal tumors: systematic review and meta-analysis.

CONTEXT: Contrast-enhanced ultrasound (CEUS) is a cost-effective radiation-free diagnostic method that can be used for renal tumor postoperative visualization after ablative treatment. OBJECTIVE: To assess CEUS diagnostic accuracy comparing with CT and MRI as a follow-up method in short-term and long-term postoperative periods after renal tumor ablation. MATERIALS AND METHODS: A systematic review and meta-analysis were performed in Scopus and Medline databases using the query "(kidney OR rena* OR RCC) AND (ablation OR RFA OR MWA OR cryo*) AND CEUS". The endpoint of the study was the evaluation of the overall accuracy of CEUS. RESULTS: Twelve trials were included in the review. With CT or MRI as a reference, for a short-term group (< 6 weeks after ablation) pooled sensitivity was 90.2%, I2 = 0%; pooled specificity was 99.3%, I2 = 0%; pooled NPV was 98.6%, I2 = 0%; pooled PPV was 94.6%, I2 = 0%; the AUC on the SROC curve was 0.971. For the long-term group (> 6 weeks after ablation), pooled sensitivity was 95.3%, I2 = 0%; pooled specificity was 97.6%, I2 = 0%; PPV was 74.2%, I2 = 4%; NPV was 99.4%, I2 = 5%; AUC = 0.93. CONCLUSION: CEUS has high sensitivity and specificity in ruling out the presence of local recurrence after renal tumor ablation with a higher risk of false-positive results within follow-up > 6 weeks compared with that for CT or MRI. Further studies with a unified protocol and morphological control of local renal tumor recurrence after ablation are needed.

Role of monocarboxylate transporters and glucose transporters in prostate cancer.

OBJECTIVES: Currently, research of new diagnostic approaches to detect clinically significant prostate cancer is relevant because of the importance of early detection of aggressive forms of the disease, often challenging, even when using modern diagnostic tools. The aim of this review is to present the current knowledge regarding monocarboxylate transporters' and glucose transporters' expression as a component of glycolytic phenotype definition in prostate cancer cells. METHODS: We searched PubMed and Scopus databases. Twenty-six articles from 2003 to 2022 were included. Literature research and selection were carried out based on the recommendations of the PRISMA statement. RESULTS: The presence of "lactate shuttle" in the tumor tissue is associated with a worse prognosis. Increased expression of MCT2, MCT4, GLUT1, and down-regulation of GLUT3 are associated with prostate adenocarcinoma. MCT4 expression level correlates with the grade of tumor malignancy and disease prognosis. Up-regulation of GLUT1 and MCT4 is typical for hormone-resistant prostate cancer. Inhibition of MCT1 and MCT4 and GLUT1 in prostate cancer cells reduces their metabolic activity and growth rate, a suitable novel approach for targeted therapy. CONCLUSION: Review of the current studies showed that expression of certain MCTs and GLUTs types are associated with prostate cancer and some of them correlate with high malignancy and poor prognosis. Detection by immunohistochemistry of these transporters could represent a new diagnostic tool to identify aggressive forms of prostate cancer, and a novel therapeutic target for selective drugs.

In vitro renal calculi destruction by a high-frequency glow discharge plasma.

Despite the progress made in the treatment of nephrolithiasis, the existing methods of renal calculi destruction are not ideal and have both advantages and disadvantages. Considering the process of high-frequency glow discharge formation on the surface of an electrode and in an electrolyte solution, we obtained the results on the destruction of renal calculi in vitro. It was shown that the destruction of kidney stones by glow discharge plasma was caused by several processes-the plasma induced effect of hydrated electrons and shock wave effect of the electrolyte stimulated by electrical breakdowns in the plasma. The plasma generation modes were configured by estimating the thickness of the vapor-gas layer in which the plasma burns. Thus, the average rate of contact destruction of renal calculi was measured depending on the plasma generator input power and time of plasma exposure. We conclude that the method of stone fragmentation by high-frequency electrolyte plasma is rather perspective and can be used in endoscopic urology for percutaneous and transurethral lithotripsy.

Retrograde intrarenal surgery versus percutaneous nephrolithotomy in larger kidney stones. Could SuperPulsed Thulium-fiber laser change the game?

INTRODUCTION: The aim of this article was to compare retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PCNL) efficacy and safety with SuperPulsed Thulium-fiber laser (SP TFL) for stones 20 mm and larger. MATERIAL AND METHODS: Patients with large kidney stones (20 mm and larger) were recruited to undergo PCNL or RIRS with SP TFL lithotripsy. Both groups were comparable in terms of stone size and density, operation time, laser-on time (LOT), stone-free rate, residual fragments and complication rate. Stone retropulsion and visibility were assessed based on the surgeon's feedback using Likert scales. RESULTS: A total of 14 and 56 patients were included in the RIRS and PCNL groups, respectively. The mean stone density was 833.8 ±298.3 HU in the RIRS group and 882.3 ±408.5 HU in the PCNL group (p = 0.072). The median LOT was 11.7 (10.0-15.5) min for RIRS and 10.0 (6.0-12.1) min for PCNL (p = 0.207). The median total energy for stone ablation was 13.8 (11.8-25.0) kJ for RIRS and 12.0 (7.0-20.1) kJ for PCNL (p = 0.508). The median ablation speed was 3.9 (3.9-5.7) mm3/sec for RIRS and 5.0 (4.6-11.3) mm3/sec for PCNL (p = 0.085). We found a significant correlation between retropulsion and the type of surgery performed: with higher retropulsion in the PCNL (r = 0.298 with p = 0.012). The stone-free rate at 3-months was 85.7% in RIRS and 89.3% in PCNL (p = 0.505). CONCLUSIONS: SP TFL is a safe and effective modality for lithotripsy for both, RIRS and PCNL, achieving minimal retropulsion and good visibility. No discrepancies in procedure duration, complications, or LOT were identified between the different modalities.

Minimally invasive percutaneous nephrolithotomy with SuperPulsed Thulium-fiber laser.

We aimed to assess the efficacy and safety of minimally invasive percutaneous nephrolithotomy (PCNL) with SuperPulsed Thulium-fiber laser (SP TFL) using different frequency settings. 125 patients with solitary kidney calculi of up to 55 mm in the maximum diameter underwent mini-PCNL with the SP TFL. Stone-free rate, laser-on time, ablation efficacy, energy consumption, ablation speed and complications were all analyzed. Negative low-dose computed tomography scan or asymptomatic patients with stone fragments < 2 mm were the criteria for assessing the stone-free status. In 36 patients (28.8%) low frequency regimens were used (LF: 3-19 Hz-0.5-6 J), in 75 patients (60%) high frequency regimens were chosen (HF: 20-49 Hz-0.2-2 J) and in 14 (11.2%) patients higher frequency (HRF: 50-200 Hz-0.1-0.5 J) regimens were preferred. The mean age was 52 ± 1.8 years. Median stone diameter and median stone volume were larger at low frequency regimens compared to high frequency regimens. Ablation efficacy (J/mm3) was lower at low rather than at high frequency regimens. Ablation speed (mm3/sec) was higher at low compared to high frequency regimens. Surgeons reported minimal and absent retropulsion at higher frequency regimens. The best visibility was observed at high frequency regimens. The overall stone free rate (SFR) at 3 months was 85%. The majority of the postoperative complications were classified between Clavien grades I-II. SP TFL is an effective and safe tool for performing mini-PCNL regardless of the laser settings.

Superpulsed Thulium Fiber Laser for Stone Dusting: In Search of a Perfect Ablation Regimen-A Prospective Single-Center Study.

Objective: To compare the efficacy of the standard and higher frequency regimens for superpulsed thulium fiber laser (SP TFL) retrograde intrarenal surgery (RIRS). Materials and Methods: A prospective study of patients with renal calculi of 10-30 mm was performed. For RIRS, we used the SP TFL (NTO IRE-Polus, Russia) and a 9.5F flexible ureteroscope with 270° deflection and 3.6F working channel. Retropulsion and visibility were assessed based on the surgeon's feedback using three-point Likert scales. The stone-free rate was assessed at 3 months with CT. Results: A total of 40 patients were included in the study with a mean age of 56 years, mean stone density of 880 ± 381 HU, mean stone size of 16.5 ± 6.8 mm, and median stone volume of 883 (interquartile range 606-1664) mm3. Both ablation efficacy and speed were higher in the 200-Hz mode (2.7 J/mm3vs 3.8 J/mm3 and 5.5 mm3/second vs 8.0 mm3/second, respectively); moreover, the higher frequency correlated with increased ablation speed (r = -0.21, p = 0.019). However, both increased energy and frequency did not lead to increase of laser-on time or intraoperative complication rates. Conclusions: SP TFL is able to effectively disintegrate stones during RIRS with minimal complication rates. The use of higher frequency regimens showed higher efficacy and ablation speed and was not associated with increased complication rates.

Three-dimensionally printed non-biological simulator for percutaneous nephrolithotomy training.

Objective: We sought to improve the educational and pre-operative training on various stages of percutaneous nephrolithotomy (PCNL) under fluoroscopic and ultrasound guidance. We developed a three-dimensional (3D) printed simulator (3D-printed PCNL model) for urological trainees.Methods: 40 s year urology residents were randomly assigned into two groups, completing PCNL surgical steps on a URO Mentor™ surgical simulator (Group A) or on our new 3D-printed PCNL model (Group B). Following the training, both groups completed a standardized questionnaire (Likert scale from 0 to 10) which we used to asses the learning curve associated with PCNL training.Results: The mean score of Group A was 65.2/80 while Group B was 76.1/80. Mann-Whitney U-test showed no significant difference between the groups (U = 16, p < 0.05).Conclusion: The 3D-printed PCNL model developed is a novel and highly effective tool that can facilitate enhanced endourological education and personalized pre-operative planning for urolithiasis cases. According to the criteria tested, residents who used our 3D-printed PCNL models performed better under all metrics.

Extracorporeal ureter handling during laparoscopic pyeloplasty: tips and tricks for beginners.

INTRODUCTION: Laparoscopic preparation of the ureter is a challenging part of upper urinary tract reconstruction, due to limited depth perception provided by the camera and lack of wristed motion of most laparoscopic instruments needed for adequate spatulation and scar tissue removal. One solution has been to perform the more difficult portions of the surgery in an extracorporeal manner. A hybrid intracorporeal-extracorporeal approach to upper tract ureteral reconstruction facilitates ureteral preparation at the stage of mastering the technique. MATERIAL AND METHODS: This retrospective study included 100 patients with primary ureteropelvic junction obstruction, who underwent laparoscopic pyeloplasty from 2014 to 2017. The patients were stratified into 2 groups: those who underwent conventional laparoscopic surgery and those who were managed with the hybrid approach. For the hybrid approach, externalizing the ureter to skin level required additional mobilization of the upper urinary tract. RESULTS: A total of 47 patients underwent conventional laparoscopic pyeloplasty and 53 - hybrid surgery. The maximum body mass index was 32. The hybrid approach was 8.5 minutes shorter compared to the conventional approach (p <0.001). No complications higher than Clavien-Dindo IIIb (n = 2) were observed (in both groups). Complete success (the resolution of pain and/or hydronephrosis) was observed in 92.5% in the hybrid group and in 95.7% in the conventional treatment group. CONCLUSIONS: Hybrid pyeloplasty may be considered safe and effective. It has the advantage of making the surgery less challenging and time-consuming while offering improved precision. The advantages of the technique are particularly apparent during training. This technique can be recommended in the learning process of the surgeon.