Superpulsed Thulium Fiber Laser Research Articles

Editorial Comment from Dr Anan to Endoscopic lithotripsy with a SuperPulsed thulium-fiber laser for ureteral stones: A single-center experience.

Editorial Comment from Dr Anan to Endoscopic lithotripsy with a SuperPulsed thulium-fiber laser for ureteral stones: A single-center experience.

Endoscopic lithotripsy with a SuperPulsed thulium-fiber laser for ureteral stones: A single-center experience.

To estimate the efficacy and safety of SuperPulsed thulium-fiber laser ureteral lithotripsy and to identify optimal laser settings. Patients with solitary stones were prospectively included. Lithotripsy was performed with a SuperPulsed thulium-fiber laser (NTO IRE-Polus, Fryazino, Russia) using a rigid ureteroscope 7.5 Ch (Richard Wolf, Knittlingen, Germany). We analyzed the efficacy of lithotripsy by measuring total energy required for stone disintegration, "laser-on" time, ablation speed, ablation efficacy, and energy consumption. Stone retropulsion and visibility were assessed using a three-point Likert scale. Complications were assessed using the Clavien-Dindo classification system. A total of 149 patients were included. The mean stone density was 985±360 Hounsfield units, the median (interquartile range) stone volume was 179(94-357) mm3 . The median (interquartile range) total energy was 1 (0.4-2)kJ, and laser-on time 1.2 (0.5-2.7)min. The median (interquartile range) stone ablation speed was 140(80-279) mm3 /min, energy for ablation of 1mm3 was 5.6 (3-9.9)J/mm3 and energy consumption was 0.9 (0.6-1)J/min. A correlation was found between retropulsion and the energy used (r=0.5, P<0.001). Multivariable analysis showed energy to be a predictor of increased retropulsion (odds ratio 65.7, 95% confidence interval 1.6-2774.1; P=0.028). No predictors for worse visibility were identified. The SuperPulsed thulium-fiber laser provides effective and safe lithotripsy during ureteroscopy regardless of stone density. Fiber diameter and laser frequency do not influence visibility or safety. Optimal laser settings are 0.5J×30Hz for fragmentation and 0.15J×100Hz for dusting.

P089 - Thulium fiber laser fulguration in combination with thulium “En bloc” technique resection of multifocal bladder tumor using SuperPulse Thulium Fiber Laser

P089 - Thulium fiber laser fulguration in combination with thulium “En bloc” technique resection of multifocal bladder tumor using SuperPulse Thulium Fiber Laser

Mechanism of Lithotripsy by Superpulse Thulium Fiber Laser and Its Clinical Efficiency

Thulium fiber laser with a wavelength of 1.94 µm is widely used in urology for lithotripsy. This paper studies the mechanism of lithotripsy and evaluates its clinical efficiency using the superpulse thulium fiber laser with a wavelength of 1.94 µm and a peak power of 500 W. An experimental setup was developed to study the mechanism of lithotripsy. The superpulse thulium fiber laser (TFL) with a wavelength of 1.94 µm with a peak power of 500 W (FiberLase U2 from “IRE-POLUS” Ltd., Fryazino, Moscow Region, Russia) was used for the lithotripsy of stone phantoms (BegoStone). The processes were recorded with a high-speed camera. The acoustic signals registered during lithotripsy were studied with wideband and needle hydrophones. The main mechanism of lithotripsy performed by using superpulse TFL was thermal cavitation in the water-filled pore space and thermal destruction of the phantom. During the clinical application of the superpulse thulium fiber laser, the high efficiency of laser lithotripsy was established. The performed optical and acoustic studies showed that the mechanism of the destruction of stones was based on the synergic effect of the explosive boiling of water in the pore space of the stone, and its thermal destruction is associated with the heating of the stone to several hundred degrees with laser radiation.

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.

PT132 - In vitro comparison of the induced vapor bubbles between 150µm and 272µm-core-diameter laser fibers with superpulsed thulium fiber laser

PT132 - In vitro comparison of the induced vapor bubbles between 150µm and 272µm-core-diameter laser fibers with superpulsed thulium fiber laser

180 - Comparison of the fissures and fragments produced with 150µm and 272µm laser fibers with superpulsed thulium fiber laser: An in vitro study

180 - Comparison of the fissures and fragments produced with 150µm and 272µm laser fibers with superpulsed thulium fiber laser: An in vitro study

178 - In vitro comparison of the induced vapor bubbles between saline solution, iodinated contrast agent, urine and deionized water with 150µm-core-diameter laser fiber with superpulsed thulium fiber laser

178 - In vitro comparison of the induced vapor bubbles between saline solution, iodinated contrast agent, urine and deionized water with 150µm-core-diameter laser fiber with superpulsed thulium fiber laser

PT131 - In vitro comparison of ablation rates between superpulsed thulium fiber laser and ho:Yag laser for endocorporeal lithotripsy

PT131 - In vitro comparison of ablation rates between superpulsed thulium fiber laser and ho:Yag laser for endocorporeal lithotripsy

181 - Super-pulse thulium-fiber laser for lithotripsy: First clinical experience in percutaneous nephrolithotomy

181 - Super-pulse thulium-fiber laser for lithotripsy: First clinical experience in percutaneous nephrolithotomy

The impact of the laser fiber-tissue distance on histological parameters in a porcine kidney model.

To evaluate the impact of the fiber-tissue distance on histological parameters in a porcine kidney model. Four lasers were tested at 60W using a 600-µm bare-ended fiber: a continuous wave (cw) thulium fiber laser (TFL), a super pulsed (SP) TFL, a Ho:YAG laser, and a blue diode laser (BDL). All tissue samples were mounted on a motorized XY-translation stage. The fiber-tissue distance was changed within a range from 0to 6mm. Ten incisions were made with each laser at each distance. Afterwards, the tissue samples were sliced with a microtome for lactate dehydrogenase staining to determine zones of thermal damage. In contact mode, the largest incision depth was found for the cw TFL (1.7 ± 0.1mm) compared to the SP TFL (1.0 ± 0.1mm), BDL (0.9 ± 0.1mm) and HoYAG laser (1.1 ± 0.1mm), respectively. With regard to the coagulative properties, the SP TFL and the Ho:YAG laser showed comparable coagulation depths with 0.7 ± 0.1 and 0.6 ± 0.1mm, respectively. At 2mm fiber-tissue distance, the Ho:YAG laser was the only laser that vaporized tissue (incision depth: 0.2 ± 0.1mm). The BDL was the only laser that caused coagulation at a distance of 3-5mm. Our results support the clinical observation that cw TFL must be defocused for best coagulation, while the coagulation depth of the SP TFL remains nearly constant within the range of 0-3mm. Increasing the distance of the laser fiber to the tissue up to 5mm did not cause significant differences with regard to coagulation depth using the BDL.

Initial Experiences Using Super Pulse Thulium Fiber Laser: Multipurpose Applications and the Assessment of Urologists' First Impression

Abstract Introduction: The super pulse thulium fiber (SPTF) laser has recently been acclaimed by more efficient lithotripsy activities, shorter laser, and treatment times demonstrated in preclinica...

PD07-12 THULIUM FIBER LASER LITHOTRIPSY IS SAFE, EFFICIENT AND EFFECTIVE IN MINIPCNL: THE INITIAL NORTH AMERICAN EXPERIENCE

You have accessJournal of UrologyStone Disease: Surgical Therapy II (PD07)1 Apr 2020PD07-12 THULIUM FIBER LASER LITHOTRIPSY IS SAFE, EFFICIENT AND EFFECTIVE IN MINIPCNL: THE INITIAL NORTH AMERICAN EXPERIENCE Maurilio Garcia-Gil*, Ben H. Chew, Mitchell R. Humphreys, Wilson Molina, Raphael V. Carrera, and Bodo Knudsen Maurilio Garcia-Gil*Maurilio Garcia-Gil* More articles by this author , Ben H. ChewBen H. Chew More articles by this author , Mitchell R. HumphreysMitchell R. Humphreys More articles by this author , Wilson MolinaWilson Molina More articles by this author , Raphael V. CarreraRaphael V. Carrera More articles by this author , and Bodo KnudsenBodo Knudsen More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000834.012AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The in vitro effects of thulium fiber laser (TFL) for lithotripsy has been previously described.1 We aim to describe the first North American clinical experience in the use of thulium laser lithotripsy in mini-PCNL. METHODS: A consecutive series of patients undergoing mini-PCNL with the TFL (SoltiveTM, Olympus Surgical) at two institutions was reviewed. Mini-PCNL with 16.5F dilation/17.5 sheath was performed with Storz MIPS system. The TFL was utilized in all cases for lithotripsy. Dust, stone debris, and fragments were cleared in standard fashion through nephrostomy sheath. Visual and fluoroscopic stone clearance was confirmed for all patients. Operative technique and postoperative management were maintained at the institutional standard. RESULTS: Six patients underwent mini-PCNL with TFL. Five cases were unilateral and performed supine and one patient had a bilateral mini-PCNL in the prone position. Mean age was 51, mean BMI was 30. Mean Charlson Comorbidity Index was 1.3 and mean ASA score was 2.8. 3 of 7 renal units had a single primary stone vs. 4 of 7 with more than one significant stone. Mean stone volume in primary calculus was 4,940mm3. Laser energy settings ranged from 0.1-1.0J and rate ranged from 20-500Hz. Mean laser time was 18.1 minutes (range = 0.9-28 min). Mean laser energy was 15.9kJ (range 1.6-64kJ). There were no intraoperative complications. 3 patients received stents, for a mean of 8 days. 2 of the 7 renal units had nephrostomy placed at end of case, both removed the next day. One patient had an extended 4 day hospital stay for treatment of bacteremia. Overall mean hospital stay was 1.6 days (range 1-4 days). Mean decrease in creatinine and hemoglobin were 0.1mg/dL and 1.0g/dL respectively. No blood transfusions were performed. CONCLUSIONS: In this initial North American cohort, the TFL has been shown to be promising as a safe and effective modality for clearance of calculi during mini-PCNL. Our group has noted synergy in the ability to clear stone when TFL is used in combination with supine mini-PCNL, in both fragmentation and dusting modes. Larger cohort and longer follow up is needed for further evaluation of this new technology. 1. Knudsen* B, Chew B, Molina W. MP79-1: SUPER PULSE THULIUM FIBER LASER COMPARED TO 120W HOLMIUM:YAG LASER: IMPACT ON RETROPULSION AND LASER FIBER BURN BACK. Journal of Urology. 2019. Source of Funding: SoltiveTM Thulium Fiber Laser was provided to institutions on a trial basis © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e166-e166 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Maurilio Garcia-Gil* More articles by this author Ben H. Chew More articles by this author Mitchell R. Humphreys More articles by this author Wilson Molina More articles by this author Raphael V. Carrera More articles by this author Bodo Knudsen More articles by this author Expand All Advertisement PDF downloadLoading ...

MP22-05 EFFICACY OF SUPER-PULSE THULIUM FIBER LASER IN ENDOSCOPIC MANAGEMENT OF LOWER URETERIC STONES IN INDIAN POPULATION

INTRODUCTION AND OBJECTIVE:Super-Pulse Thulium fiber laser is a novel intracorporeal lithotripter used for management of urinary tract stones. It has several advantages over Holmium-YAG laser inclu...

PD04-12 IN VITRO COMPARISON OF ABLATION RATES BETWEEN SUPERPULSED THULIUM FIBER LASER AND HO:YAG LASER FOR ENDOCORPOREAL LITHOTRIPSY

INTRODUCTION AND OBJECTIVE:Holmium: YAG (Ho:YAG) laser is currently the standard for lithotripsy. Recently, Superpulsed Thulium Fiber Laser (TFL) has been evaluated as an alternative for lithotrips...

PD34-06 FLEXIBLE URETEROSCOPY FOR LOWER POLE RENAL STONES: NOVEL SUPERPULSE THULIUM (TM) FIBER LASER LITHOTRIPSY. FIRST CLINICAL RESULTS

You have accessJournal of UrologyStone Disease: Surgical Therapy V (PD34)1 Apr 2020PD34-06 FLEXIBLE URETEROSCOPY FOR LOWER POLE RENAL STONES: NOVEL SUPERPULSE THULIUM (TM) FIBER LASER LITHOTRIPSY. FIRST CLINICAL RESULTS Dmitry Korolev*, Roman Klimov, Dmitry Tsarichenko, Mikhail Enikeev, Alim Dymov, Stanislav Ali, Gagik Akopyan, Vladimir Lekarev, Mark Taratkin, Leonid Rapoport, Dmitry Enikeev, and Peter Glybochko Dmitry Korolev*Dmitry Korolev* More articles by this author , Roman KlimovRoman Klimov More articles by this author , Dmitry TsarichenkoDmitry Tsarichenko More articles by this author , Mikhail EnikeevMikhail Enikeev More articles by this author , Alim DymovAlim Dymov More articles by this author , Stanislav AliStanislav Ali More articles by this author , Gagik AkopyanGagik Akopyan More articles by this author , Vladimir LekarevVladimir Lekarev More articles by this author , Mark TaratkinMark Taratkin More articles by this author , Leonid RapoportLeonid Rapoport More articles by this author , Dmitry EnikeevDmitry Enikeev More articles by this author , and Peter GlybochkoPeter Glybochko More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000905.06AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The SuperPulse Thulium (Tm) fiber laser (wavelength of 1.94 µm) has been recently introduced as a directed-energy source for urology. Preclinical studies have shown a significant potential of the SuperPulse Tm fiber laser (SP TFL) for lithotripsy. However, clinical reports of using SP TFL to treat urolithiasis are still few and limited. Of special interest are challenging cases, e.g., lower pole stones, when extreme deflection of the instrument is required. To evaluate the effectiveness of the SuperPulse Tm fiber laser in the management of lower pole small calyceal stones during flexible ureteroscopy (F-URS). METHODS: The SuperPulse Tm fiber laser device (Urolase 2, IRE Polus, Fryazino, Russia) has been cleared for clinical use by the Ministry of Health of Russian Federation. Study protocol has been approved by the Ethical Review Committee. Between January2018 and February 2019, 130 patients with kidney stones have undergone Thulium fiber laser lithotripsy during F-URS. We retrospectively analyzed 15 of this patients with a single radiopaque lower pole calculus that were included in the present study. Stone size, stone density, lithotripsy time (from the first to last footswitch press) and “lasering” (laser emission) time were measured. The SP TFL was used for stone disintegration with different settings in dusting and fragmentation modes (0.1 – 4J, 7-300Hz, 6-40W) via a fiber with a 200-μm core diameter. Low dose CT scanning was performed on POD 90 to assess SFR. RESULTS: Stone size ranged from 4 to 17 mm and stone density varied from 350 to 1459 HU. The average lithotripsy timewas 12 min (3-30 min). The average “lasering” time was 1.3 min (0.4-2.5 min) and the mean hospital stay was 1.1 ± 0.3 days. In all cases we reached the lower pole stone containing calyx with a laser fiber. The complication rates were evaluated by using the Clavien-Dindo grading system and did not exceed GII. The overall postoperative complication rate was 26.6% (GI 20%; GII 6.6%). SFR on POD 90 was achieved in 86.6% of cases. CONCLUSIONS: F-URS with SuperPulse Tm fiber laser is safe and effective option in the management of lower pole small calyceal stones. The possibility of using small laser fibers gives better instrument deflection which make possible to reach lower pole calyceal stones even with acute lower pole infundibulopelvic angle (IPA). Source of Funding: non © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e713-e713 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Dmitry Korolev* More articles by this author Roman Klimov More articles by this author Dmitry Tsarichenko More articles by this author Mikhail Enikeev More articles by this author Alim Dymov More articles by this author Stanislav Ali More articles by this author Gagik Akopyan More articles by this author Vladimir Lekarev More articles by this author Mark Taratkin More articles by this author Leonid Rapoport More articles by this author Dmitry Enikeev More articles by this author Peter Glybochko More articles by this author Expand All Advertisement PDF downloadLoading ...

PD30-01 COMPARISON OF SMALL CORE DIAMETER LASER FIBERS USED FOR LITHOTRIPSY WITH A 120W HO

INTRODUCTION AND OBJECTIVE: Small core (240 - 300μm) fibers are used for Ho:YAG laser lithotripsy. The SOLTIVE SuperPulsed Thulium Fiber (SPTF) Laser permits the use ≤ 200μm core sized fibers. We evaluate a 150μm and 200μm core size fiber used with the SPTF laser compared to a 242μm and 230μm core fiber used for Ho:YAG laser lithotripsy. METHODS: Fiber flexibility, mechanical breakdown and thermal breakdown are tested with the BSC Accumax 200 (242μm core), Lumenis SlimLine MOSES™ (230μm core), Olympus 200 SPTF (200μm core) and Olympus 150 SPTF (150μm core). Fiber flexibility is shown via a 3-point bend test 5x for each fiber size (results in N/mm). A 2-plate break test measures the tightest diameter a fiber could be bent before failure (N=5). For thermal breakdown, fibers were bent 180° at a diameter of 3cm during firing at pulse energies of 0.2, 0.5, 1, and 2 J, all at 10 Hz, in successive order for 15s or until fiber failure. If no failure, the bend diameter (BD) was reduced and the testing repeated until failure or 0.2 cm reached. BD = 3, 2, 1, 0.5, 0.4, 0.3, and 0.2cm were sequentially tested. Five trials for each fiber were performed. RESULTS: The 150 SPTF was less stiff than the 200 SPTF (Mean 0.0055 vs 0.0076 N/mm). Both fibers were less stiff than the Accumax 200 and MOSES 200 (Mean 0.014 & 0.0098 N/mm). Mean BD before mechanical failure was 0.099 mm for the 150 SPTF, 1.58 mm for the MOSES 200, 1.74 mm for the Accumax 200 and 1.861mm for the 200 SPTF. For thermal breakdown testing, the 150 SPTF reached BD = 0.3 cm prior to failing in 3/5 trials, with a BD = 0.2cm in 2/5, at pulse energy of 0.2 J. The 200 SPTF BD = 0.4 cm prior to failing in 2/5 trials, with a BD = 0.3cm in 3/5 trials, at a pulse energy of 0.2 J. The Accumax 200 failed at BD = 0.4 – 1.0 cm and pulse energies of 0.2 – 1.0J. For the MOSES™ 200, BD = 0.5cm in all trials, failing at pulse energies of 0.2-2.0J (Figure 1). CONCLUSIONS: The 150 and 200 SPTF fibers were more flexible and able to bend to a smaller diameter than the Accumax 200 and MOSES™ 200 fibers with laser energy pulsing through them. These fibers may provide clinical benefits during laser lithotripsy procedures, especially in the difficult to reach lower pole.Source of Funding: Olympus Surgical

How Lasers Ablate Stones: In Vitro Study of Laser Lithotripsy (Ho:YAG and Tm-Fiber Lasers) in Different Environments.

Introduction: There are two main mechanisms of stone ablation with long-pulsed infrared lasers: photothermal and photomechanical. Which of them is primary in stone destruction is still a matter of discussion. Water holds importance in both mechanisms but plays a major role in the latter. We sought to identify the prevailing mechanism of stone ablation by evaluating the stone mass loss after lithotripsy in different media. Materials and Methods: We tested a holmium:yttrium-aluminum-garnet (Ho:YAG) laser (100 W; Lumenis), a thulium-fiber laser U1 (TFL U1) (120 W; NTO IRE-Polus, Russia), and a SuperPulse thulium-fiber laser U2 (TFL U2) (500 W; NTO IRE-Polus). A single set of laser parameters (15 W = 0.5 J × 30 Hz) was used. Contact lithotripsy was performed in phantoms (BegoStones) in different settings: (a) hydrated phantoms in water, (b) hydrated phantoms in air, (c) dehydrated phantoms in water, and (d) dehydrated phantoms in air. Laser ablation was performed with total energy of 0.3 kJ. Phantom mass loss was defined as the difference between the initial phantom mass and the final phantom mass of the ablated phantoms. Results: All lasers demonstrated effective ablation in hydrated phantoms ablated in water; no visual differences between the lasers were detected. The ablation of dehydrated phantoms in air was also effective with visible vapor during ablation and condensation on the cuvette wall. Dehydrated phantoms in water and in air show minimal to no ablation accompanied with formation of white crust on phantom surface. Among laser types, TFL U2 had the highest phantom mass loss in all groups except for dehydrated phantoms ablated in air. Conclusions: Our results suggest that both photothermal and thermomechanical ablation mechanisms (explosive vaporization) occur in parallel during laser lithotripsy. In Ho:YAG and TFL U2 stone ablation explosive vaporization prevails, whereas in TFL U1 ablation photothermal mechanism appears to predominate.

Thermoexpandable Urethral Nickel-Titanium Stent Memokath for Managing Urethral Bulbar Stricture After Failed Urethroplasty.

Introduction: Urethral stenting became popular two decades ago, but nowadays its frequency is slightly decreased because of the rising application of urethroplasty. Today urethral stenting is reserved only for failure after urethral reconstruction or in cases when the plastic surgery is unfavorable. The Memokath stent (Pnn Medical A/S, Kvistgaard, Denmark) is manufactured from a biocompatible alloy of nickel and titanium and known to be the most popular in this field. Case Description: A 38-year-old man with a history of 9 years Memokath urethral stenting was admitted to our clinic with obstructive lower urinary tract symptoms. The indication for Memokath stenting was repeated recurrences after endoscopic and reconstructive operations. The plain radiography showed a normal position of the stent and only the endoscopic examination revealed its total calcification. New superpulse thulium fiber laser has been used to free the stent from the stones and safely remove it without additional urethral injury. Results: The postoperative time was within normal limits, the catheter was removed on the fourth day after operation. Three months follow-up was without stricture recurrence. We continue active surveillance of the patient. Conclusion: The calcification of the stent could be properly diagnosed endoscopically; the Memokath stent could be safely removed in 9 years after implantation; thulium fiber laser is effective and safe in the management of encrusted urethral stent.

Оптимизация параметров суперимпульсного тулиевого волоконного лазера с длиной волны излучения 1,94 мкм при миниперкутанной литотрипсии

At present, minipercutaneous nephrolithotripsy is a highly effective and safe method for fragmentation of stones with sizes up to 3 cm. The use for lithotripsy of a holmium: yttrium aluminum garnet laser with wavelength 2.1 μm (Ho:YAG) is a common practice today. Of late, however, more attention is paid to a new superpulse thulium fiber laser with wavelength 1.94 μm and maximum output power 40 W. The use of a thulium laser with pulse energy 0.025–6 J and a high repetition rate (to 1600 Hz) permits to obtain (compared with a holmium laser) better results of stone dusting. Objective. Selection of the optimal modes of stone fragmentation in minipercutaneous nephrolithotripsy with the use of a superpulse thulium fiber laser with wavelength 1.94 μm and maximum output power 40 W in patients with nephrolithiasis. Patients and methods. The study included patients (n = 171), who underwent minipercutaneous nephrolithotripsy using a superpulse thulium fiber laser during the period from February 2018 to July 2019. The following parameters of laser radiation were used: pulse energy 0.1-6 J, power 6-40 W, pulse rate 30-300 Hz. The impact of modes on endoscopic visualization and retropulsion was assessed intraoperatively. Results. Statistical analysis of the specificities of the most often used modes was conducted: No 1 – «0.15 J, 200 Hz, 30 W», No 2 – «0.5 J, 30 Hz, 15 W», No 3 – «0.8 J, 31.25 Hz, 25 W», No 4 – «0.8 J, 37.5 Hz, 30 W», No 5 – «1.5 J, 15 Hz, 30 W», No 6 – «1.5 J, 26.6 Hz, 40 W», No 7 – «2 J, 15 Hz, 30 W», No 8 – «2 J, 20 Hz, 40 W», No 9 – «4 J, 10 Hz, 40 W»; their effects on retropulsion and on endoscopic visualization were studies. The stone free rate was assessed on the first post-operative day according to the findings of low-dose CT. Conclusion. Study of the modes of thulium fiber lithotripsy, assessment of retropulsion and endoscopic visualization depending on the choice of emitted radiation parameters of a thulium fiber laser make it possible to improve the outcomes of operative treatment in patients with nephrolithiasis. Key words: minipercutaneous, nephrolithotripsy, nephrolithiasis, MPNL, thulium fiber lithotripsy, retropulsion, visibility, superpulse thulium fiber laser, wavelength 1.94 μm, stone free rate