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INTRODUCTION AND OBJECTIVES Conventional renal stone dusting is challenging; the holmium laser (Ho:YAG) and holmium with MOSES Effect (Ho:YAG-MOSES) fail to uniformly produce fragments

Background: It is estimated that more than 1 million people are diagnosed with liver malignancy each year and one of the treatments is radioembolization with Y-90 and Ho-166. Objective: The aim of this study is to calculate the absorbed doses caused by Y-90 and Ho-166 in tumor and liver parenchyma using a phantom via Monte Carlo method. Methods: A liver model phantom including a tumor imitation of sphere (r =1.5cm) was defined in GATE. The total activity of 40 mCi Y-90 and Ho-166 was prescribed into tumor imitation as source and 2x2x2 mm3 voxel-sized Dose- Actors were identified at 30 locations. The simulation, performed to calculate the absorbed doses left by particles during 1 second for Y-90 and Ho-166, was run for a total of 10 days and 11 days, respectively. Total doses were calculated by taking the doses occurring in 1 second as a reference. Results: The maximum absorbed doses were found to be 2.334E+03±1.576E+01 Gy for Y-90 and 7.006E+02±6.013E- 01 Gy for Ho-166 at the center of tumor imitation. The minimum absorbed doses were found to be 2.133E-03±1.883E- 01 Gy for Y-90 and 1.152E-02±1.036E-03 Gy for Ho-166 at the farthest location from source. The mean absorbed doses in tumor imitation were found to be 1.50E+03±1.36E+00 Gy and 4.58E+02±4.75E-01 Gy for Y-90 and Ho-166, respectively. And, the mean absorbed doses in normal parenchymal tissue were found to be2.07E+01±9.58E-02 Gy and 3.79E+00±2.63E-02 Gy for Y-90 and Ho-166, respectively. Conclusion: Based on the results, Ho-166 is a good alternative to Y-90 according to dosimetric evaluation.

OBJECTIVE: To assess the fiber-tissue interaction through ablation, coagulation, and carbonization characteristics of the Ho:YAG laser and Super Pulsed Thulium Fiber Laser (TFL) in a non-perfused p...

Background: Holmium:yttrium aluminum garnet laser (Ho:YAG) is still considered the gold standard in laser lithotripsy. There is a large body of literature comparing the capabilities of Ho:YAG and thulium fiber lasers (TFLs). The novel, pulsed thulium:yttrium aluminum garnet laser (p-Tm:YAG) evaluation model has only been compared with Ho:YAG in terms of its dusting performance to date. It was this study's aim to compare the p-Tm:YAG's dusting efficiency with that of a chopped TFL. Materials and Methods: During the laser ablation procedure, while the laser device was emitting light, the laser fiber was spiraled across the surface of a uniform kidney stone model via software. We relied on the stone model's difference in weight before and after the dusting procedure to assess the dusting efficiency and assessed each laser device's dusting efficiency at various preset laser configurations and laser fiber-motion speeds. We compared both laser devices' laser configurations, which were identical in pulse energy and frequency, while keeping in mind that the pulse duration differed significantly. In addition, we tested each laser device's capability. Results: The average ablated weight across all laser configurations was 0.61 g (standard deviation [SD] = 0.44 g) for p-Tm:YAG and 0.76 g (SD = 0.51 g) for TFL. After statistical analysis, we found no significant difference in ablated weight between the laser devices (U = 1715.5, p-value = 0.11). The maximum permissible frequency configuration for TFL was 1600 Hz, which resulted in the worst overall dusting output. Conclusions: We observed that the p-Tm:YAG's dusting efficiency resembled that of TFL in the identical pulse energy and frequency laser configurations. The ablation efficiency did not seem to be affected by the laser devices' differences in pulse duration. Slower laser fiber-motion speeds resulted in more efficient ablation. When using the maximum preset frequency and power configuration, TFL's dusting efficiency appeared to be inefficient.

Introduction: Manipulation of Holmium:Yttrium–Aluminum–Garnet laser parameters such as pulse energy (PE), frequency, and duration can impact laser lithotripsy ablation efficiency. In 2017, Lumenis introduced Moses™ Technology, which uses pulse modulation to enhance the delivery of energy from fiber to stone as well as to minimize stone retropulsion. Since the introduction of Moses Technology, other companies have brought additional pulse modulation concepts to market. The purpose of this in vitro study is to compare the pulse characteristics and stone ablation efficiency of Lumenis Moses Technology with Quanta's Vapor Tunnel™. Materials and Methods: Submerged BegoStone phantoms were systematically ablated using either the Lumenis Moses Pulse 120H or the Quanta Litho 100 clinical laser system. Two PEs (0.4 and 1 J), three fiber-stone standoff distances (SDs) (0.5, 1, 2 mm), and all available pulse duration and modulation modes for each laser were tested in combination. Fiber speed was adjusted to scan across the stone surface at either 1 or 10 pulses/mm to form single pulse craters or an ablation trough, respectively. Volumes of single craters and 1 mm trough segments were imaged and quantified using optical coherence tomography. Results: Ablation volumes decreased with decreasing PE and increasing SD. Statistically significant variability was seen between pulse types (PT) at every tested parameter set. Among pulse modulation modes, Moses Distance (MD) was superior at 0.5 mm in all testing and at 2 mm in trough testing. Vapor Tunnel (VT) was superior in 2 mm single crater testing. All modulated pulses performed similarly at 1 mm. Conclusions: In this benchtop model of laser lithotripsy, stone ablation was significantly impacted by PT. MD demonstrated superior or noninferior stone ablation at most tested parameters. VT maintained its efficacy the best as SD increased. Future work should focus on the mechanistic differences of these modes relative to other traditional laser pulse modes.

Background Limited research has focused on success with hospital discharge on the same day of surgery after holmium laser enucleation of the prostate (HoLEP). Objective To determine the success of same-day discharge in our HoLEP cohort and factors associated with this approach. Design, setting, and participants A retrospective review of our prospectively maintained HoLEP database demonstrated that 473 adult males underwent HoLEP from July 2018 to December 2019 at a tertiary referral center and high-volume HoLEP hospital. Patients were divided into groups according to planned inpatient admission (PIA), successful same-day discharge (SDD), or unplanned admission (UA). Outcome measurements and statistical analysis The PIA, SDD, and UA groups were assessed for differences in preoperative demographic data, perioperative surgical data, and postoperative follow-up data. SDD and UA were then compared to determine if any specific factors predicted UA, including univariate and multivariate logistic regression analyses. Results and limitations Age (p = 0.0049), use of anticoagulation (p = 0.037), American Society of Anesthesiologists score of 3–4 (p = 0.0017), and enucleation time (p=0.0178) were significantly higher in the PIA group. Morcellation time (p = 0.0059) and the rate of bedside catheter irrigation (p = 0.04) were higher in the UA group. The SDD group had the highest rate of successful voiding trial (p = 0.0001). Among the three groups, there was no difference in the rate of postoperative complications (p = 0.141). In a comparison of the SDD and UA groups, morcellation time (p = 0.041), the rate of bedside clot evacuation (p = 0.004), and successful voiding trial (p = 0.003) all favored SDD. There was no difference in 90-d complications (p = 0.536). A limitation is the retrospective nature of this study. Conclusions HoLEP can be successfully performed as day surgery without an increase in postoperative complications. HoLEP as day surgery is possible for any patient who does not require admission for medical comorbidities. Patient summary Same-day discharge (SDD) after holmium laser enucleation of the prostate (HoLEP) is possible and is successful in 87.4% of patients. Patients with longer morcellation times and with post-procedure hematuria with clots are more likely to have an unplanned admission. Use of a 120-W modulated-pulse laser resulted in a higher rate of SDD success. The culture change to day surgery is time-intensive owing to education of the postsurgical care units and clinic staff, and in our experience took approximately 9 mo to seamlessly integrate SDD as our HoLEP standard of care.

Objectives: The Thulium Fiber Laser (TFL) is studied as an alternative to the holmium:yttrium-aluminium-garnet (Ho:YAG) laser for lithotripsy, with the advantage of an induced bubble stream (IBS). ...

Purpose: Previously published studies have shown small prostate size, capsular perforation and intraoperative bladder distension are associated with failed trial without a catheter (TWOC) after HoLEP. The study objective was to determine the relationship between MOSES pulse modulation versus standard laser technology and short-term catheter reinsertion following failed TWOC. Materials and Methods: The study included 487 patients who underwent HoLEP, using standard holmium laser settings (180 patients) or MOSES pulse modulation (255 patients), between August 2018 and February 2021. Catheter reinsertion defined as reinsertion following failed TWOC within 30 days of surgery. Association of pulse modulation with catheter reinsertion was examined using single and multivariable logistic regression models. Comparisons of pre and intraoperative characteristics between patients treated without and with pulse modulation were made using a Wilcoxon rank sum test for numeric characteristics or Fisher’s exact test for categorical characteristics. Results: Short-term catheter reinsertion occurred in 14% (26/180) of the standard laser setting group as compared with 10% (24/252) of the pulse modulation group. There was no statistically significant association with short-term catheter reinsertion in single (unadjusted OR [standard settings vs. pulse modulation], 1.60; 95% CI, 0.80–2.91; p=0.12) or multivariable analysis adjusting for specimen weight and operative time (adjusted OR [standard settings vs. pulse modulation], 1.44; 95% CI, 0.77–2.68; p=0.25). Conclusions: In this study, we found no association between post-HoLEP short-term catheter reinsertion following failed TWOC and MOSES pulse modulation. Although MOSES pulse modulation offers several well-documented advantages, catheter reinsertion events appear to be attributable to other factors.

Purpose The aim of this study was to compare the enucleation performances of four different types of laser devices in an ex-vivo experiment: a novel, pulsed Tm:YAG solid-state laser evaluation model (p-Tm:YAG), chopped thulium fibre laser (TFL), low-power Ho:YAG laser (LP-Ho:YAG), and a high-power Ho:YAG laser (HP-Ho:YAG). Methods Our primary aim was to endoscopically separate the fascial layers of a porcine belly using laser fibres within a time period of 60 s. The size of a “tissue pocket” was assessed numerically. The enucleation characteristics reflecting the surgeon’s experience were evaluated via the NASA Task Load Index (TLX) questionnaire and a questionnaire based on Likert scale. Results HP-Ho:YAG achieved with the available laser settings the largest overall “tissue pocket” (31.5 cm2) followed by p-Tm:YAG (15 cm2), TFL (12 cm2), and LP-Ho:YAG (6 cm2). The coagulation performances of p-Tm:YAG and TFL were rated the best. In the performance evaluation by the Likert questionnaire, HP-Ho:YAG (average score of 4.06) was rated highest, followed by p-Tm:YAG (3.94), TFL (3.38), and LP-Ho:YAG (3.25). The evaluation of the NASA-TLX performance questionnaire revealed average scores for HP-Ho:YAG, LP-Ho:YAG, TFL and p-Tm:YAG of 4.38, 4.09, 3.92 and 3.90, respectively. Conclusion We are the first to compare different laser devices and settings in an ex-vivo study. We found that the surgeons were most satisfied with the HP-Ho:YAG laser device, followed by the p-Tm:YAG. These findings could be highly relevant for future research and for the practical utilisation of laser systems in endourology.

A distributed temperature monitoring inside a cavity of ytterbium DFB and holmium fiber lasers has been demonstrated with a spatial resolution of 1 and 5 mm, respectively, for the first time to the best of our knowledge. For this, we use an optical backscatter reflectometer, which measures intracore temperature, and compare it with the data of an IR thermographic camera, which measures temperature from the surface of a fiber. In the case of holmium fiber laser pumped at a wavelength of 1125 nm with a power of 6 W, the maximum temperature variation along the ∼3-m active fiber reaches ∼60 °C. In the case of ytterbium DFB laser, we observe a strong inhomogeneity of the temperature along the DFB cavity, which leads to a significant decrease in the lasing efficiency. When pumped by a single-mode laser diode at a wavelength of 976 nm with a power of up to 526 mW, the maximum temperature difference reaches 37 °C for the 37-mm DBF cavity.

Purpose: To examine gas bubbles generated by two laser lithotripsy devices, a pulsed thulium solid-state laser and a holmium:yttrium-aluminum-garnet (Ho:YAG) device, and their possible effects in l...

Background: Holmium laser enucleation of the prostate (HoLEP) is a highly effective procedure for benign prostatic hyperplasia that is size independent and has been recommended for patients necessi...

Purpose: To compare a novel Thulium laser device with the commonly used Holmium:Yttrium-Aluminum-Garnet (Ho:YAG) laser in terms of the in vitro temperatures generated. Methods: Our study investigat...

Introduction: The advent of single-use disposable flexible ureteroscopes allows for rapid prototyping of novel endoscopes. In this regard, we sought to develop a female-specific ureteroscope, with ...

Endocorporeal laser lithotripsy (ELL) is currently the gold standard for the treatment of renal stones during retrograde intra-renal surgery (RIRS). The newly-authorised thulium fibre laser (Tm-Fibre) in now evaluated as a holmium:yttrium-aluminium-garnet (Ho:YAG) laser alternative, which is the most well-known laser source for ELL. This update aimed to present the fundamentals of pulsed lasers for EEL [technology, period, pulse characteristic (rate, duration, energy, shape), peak power, average power], and the available lithotripsy modes for both Tm-Fibre and Ho:YAG lasers.

Introduction The length of the operation to remove urinary concernments has a marked effect on the occurrence of postoperative complications in the time of the postoperative patients in the hospital. A significant factor contributing to the increase in time is the clouding of the fragmentation region, which increases the operation time and the number of complications. Purpose to develop a method of reducing the time of additional costs in contact lithotripsy with a holmium laser in order to reduce the risk of postoperative complications. Materials and methods The paper presents the own results of in vivo measurements of time intervals spent on fragmentation of stone. Fragmentation of stones in kidney was carried out by a holmium lithotripter of Triple type with the help of semirigid and flexible ureteroscopes. In the case of severe clouding of the fragmentation region, the author s technique of percutaneous micro-drainage of the kidney was used. The evaluation of the duration of the fragmentation procedure is based on statistical processing of the obtained measurement data using Excell Data Analysis tools. Results In the process of analysis of literary sources and results of own studies it was revealed that with increase in duration of contact laser lithotripsy the number of postoperative complications significantly increases. In order to reduce the time of transurethral contact holmium lithotripsy, the author s technique of percutaneous micro-drainage has been developed. By in vivo measurements and statistical processing of the data, it was found that by using the micro-drainage technique, the average additional washing time of the fragmentation region was reduced by an average of 4 times compared to the conventional technique. Conclusion By further washing the fragmentation region, it is possible to reduce the time of additional crushing costs by at least 4 times and reduce the number of postoperative complications.

Objectives To investigate the incidence of and risk factors for febrile complications (FCs) in patients undergoing holmium laser enucleation of the prostate (HoLEP). Methods This retrospective study enrolled 847 consecutive patients who underwent HoLEP in our hospital from June 2006 to December 2018. FCs were defined as a body temperature ≥38.0°C within 30 days after surgery. The incidence of FCs was determined and possible risk factors assessed using multivariate logistic regression analysis. Results Overall, 87 (10.3%) patients presented with FCs, and 6 (0.7%) had urosepsis, with no fatal complications. Multivariate logistic regression analysis revealed that patients with preoperative positive urine culture and urethral catheterization had an increased risk of FCs compared with those with a negative culture who did not need catheterization (odds ratio [OR] 2.587, 95% confidence interval [CI] 1.307-5.121). A negative urine culture with catheterization and a positive culture without catheterization were not associated with the development of FCs (OR 0.320, 95% CI 0.040-2.553 and OR 1.370, 95% CI 0.662-2.365, respectively). Other significant risk factors included preoperative serum albumin levels (OR 0.382, 95% CI 0.173-0.846) and immediate postoperative body temperature (OR 2.559, 95% CI 1.549-4.230). Conclusions FCs are relatively common among patients after HoLEP despite preoperative prophylactic antibiotic administration. Surgeons may need to consider performing screening of urine cultures prior to HoLEP, especially in patients with urethral catheterization, even if asymptomatic. If the culture is positive, prophylactic antibiotics should be tailored according to bacterial susceptibility.

Introduction: There are limited data regarding the effect of thulium laser (Tm:YAG) and holmium laser (Ho:YAG) on upper urinary tract. The aim of this study was to compare soft tissue effects of th...

Introduction surgical treatment of urinary stone disease plays an important role in urological practice. Stone fragmentation can be performed using various lithotripters, from which Holmium fiber laser (Ho: YAG) has currently taken the main place. According to the current literature, a superpulsed thulium fiber laser with a wavelength of 1.94 m and a maximum power output of 40 W showed in vitro higher efficiency compared to Ho: YAG, while having the same safety profile. The use of a thulium fiber laser with a pulse energy of 0.025-6 J and a high repetition rate (up to 1600 Hz) allows to most effectively perform stone dusting during retrograde intrarenal surgery (RIRS). Aim to improve the performance of RIRS using the 1.94m superpulsed thulium fiber laser. Materials and methods a total of 152 patients with renal stones who were treated during the period from February 2018 to July 2019 were included in the study. The analysis of the laser settings, their effect on retropulsion and visibility when performing RIRS using a superpulsed thulium fiber laser with a wavelength of 1.94 m and a maximum power output of 40 W, a peak power of 500 W, as well as an assessment of the stone-free rate the first postoperative day and 3 months after the procedure was done. Results The most frequently used settings were as following: 0.5 J, 30 Hz, 15 W (No. 1), 0.15 J, 200 Hz, 30 W (No. 2), 0.8 J, 31.25 Hz, 25 W (No. 3), 0.8 J, 37.5 Hz, 30 W (No. 4). The statistical analysis of the influence of the settings on the quality of endoscopic imaging and retropulsion was carried out. In addition, the features of each settings were analyzed. The stone-free rate on the first postoperative day was evaluated using low-dose CT. Conclusion A superpulsed thulium fiber laser with a wavelength of 1.94 m and a maximum power of 500 W has shown high efficiency in clinical practice when performing RIRS, since it allows to have good endoscopic imaging, minimal retropulsion, and to perform stone dusting, which had a positive effect on the stone-free rate. Optimization of the settings of thulium fiber lithotripsy may improve the results of surgical treatment of urinary stone disease.

PURPOSE The aim of this study was to systematically evaluate the potential to combine investigational contrast media with spectrally optimized energy-thresholding of photon-counting detector computed tomography (PCCT) for subtraction of calcified plaques in a coronary artery stenosis phantom. METHODS A small vessel phantom containing 3 fillable tubes (diameter, 3 mm each) with calcified plaques was placed into an anthropomorphic chest phantom. The plaques had incremental thicknesses ranging from 0.3 to 2.7 mm, simulating vessel stenoses ranging from 10% to 90% of the lumen diameter. The phantom was filled with 5 different investigational contrast media (iodine, bismuth, hafnium, holmium, and tungsten) at equal mass concentrations (15 mg/mL) and was imaged on a prototype PCCT at 140 kVp using optimized, contrast media-dependent energy thresholds. Contrast maps (CMs) were reconstructed for each contrast medium by applying a linear 2-material decomposition algorithm. Image noise magnitude and noise texture of CM were compared among the contrast media using the noise power spectrum. Two blinded readers independently rated the vessel lumen visualization on short-axis and the overall subjective image quality on long-axis CM relative to iodine as the reference standard. Four readers determined the highest degree of stenosis that could be assessed with high diagnostic confidence on long-axis CM. RESULTS Average image noise on CM was lower for tungsten (49 HU) and hafnium (62 HU) and higher for bismuth (81 HU) and holmium (165 HU) compared with iodine (78 HU). Noise texture of CM was similar among the contrast media. Interreader agreement for vessel lumen visualization on short-axis CM ranged from moderate to excellent (k = 0.567-0.814). Compared with iodine, lumen visualization of each reader was improved using tungsten (P < 0.001 for both readers), similar to improved using hafnium (P = 0.008, P = 0.29), similar using bismuth (P = 0.38, P = 0.69), and decreased using holmium (both, P < 0.001). Overall subjective image quality was similar for holmium and superior for tungsten, hafnium, and bismuth as compared with iodine. Higher-degree stenoses were evaluable with high confidence using tungsten (mean, 70%; interquartile range, 70%-70%), bismuth (70%; 60%-70%), and hafnium (75%; 70%-80%) compared with iodine (50%; 50%-60%) and holmium (50%; 50%-60%). CONCLUSIONS Spectral optimization in PCCT combined with investigational contrast media can improve calcium subtraction and stenosis assessment in small vessels. Contrast maps of tungsten and, to a lesser extent, hafnium as contrast media yielded superior image noise properties and improved vessel lumen visualization, along with a higher subjective image quality compared with the reference standard iodine.

Objectives: To describe the evolution of day-case success rate over the years and to identify predictive factors for prolonged hospitalization or readmissions. Methods: Retrospective review of all ...

We report the design and performance of a packaged broadband PM hybrid HDFA/TDFA in the 2000–2100 nm band using all-single-clad doped fibers. Internal small signal G = 49.1 dB, small signal NF = 6.5 dB, and P out = 3.54 W are achieved at λ s = 2051 nm. The simulated 3 dB output power bandwidth is 98 nm. Comparisons of experimental data and simulations show good agreement. We investigate through simulations an all-Holmium two stage PM optical amplifier design for comparison to the hybrid PM HDFA/TDFA.

Purpose: To evaluate the microsphere outflow dynamics and residual Ho-166 activity during and after transarterial radioembolization planning and treatment procedures, and to assess the distribution and predilection sites of residual activity in the proprietary delivery set and the microcatheter. Materials and Methods: Fifteen planning and 12 therapeutic radioembolization procedures were performed with poly-l-lactic acid microspheres loaded with Ho-166. The amount and distribution of residual activity was assessed by dose calibrator measurements and SPECT imaging. The activity flow profile from the microcatheter was assessed dynamically. For planning procedures, different injection methods were evaluated in order to attempt to decrease the residual activity. Results: The median residual activities for planning and treatment procedures using standard injection methods were 31.2% (range 17.3%–44.1%) and 4.3% (range 3.5%–6.9%), respectively. Planning residual activities could be decreased significantly with 2 injection methods similar to treatment procedures, to 17.5% and 10.9%, respectively ( P = 0.002). Main predilection sites of residual microspheres were the 3-way stopcock and the outflow needle connector. During treatment procedures, more than 80% of the injected activity is transferred during the first 3 injection cycles. Conclusion: After treatment procedures with holmium-loaded microspheres, mean residual activity in the delivery set is reproducibly low and between reported values for glass and resin microspheres. The majority of microspheres is transferred to the patient during the second and third injection cycle. An estimated residual waste of 3% to 4% may be included in the treatment activity calculation. For planning procedures, a modified injection technique should be used to avoid high residual activities.

Purpose: To examine the dusting performance of a novel solid state Thulium laser device compared to a standard holmium:yttrium-aluminum-garnet (Ho:YAG) device. Methods: This study compares a Dornie...

The 3.92 μm laser pumped by 888 and 962 nm sources in a high concentration holmium-doped InF3 fiber is predicted and verified by simulation for the first time. Most parameters involved in the numerical model are taken from published results about the fundamental properties of holmium in fluoroindate glasses. The remaining unknown parameters are estimated from published 888 nm single-wavelength pumping experimental data. Simulated results indicate that the dual-wavelength pumping system can give a more powerful output than the single-wavelength pumping system when the total launched power is at the same level. The laser output as a function of the power of each source, as well as several macro factors such as fiber length and output coupler reflectivity, are investigated to find the best condition for higher output. To evaluate the importance and influence of the known interionic energy transfer processes, we analyze the corresponding laser output and changes of population densities of laser upper and lower levels by isolating each process. This investigation gives a preliminary insight into the 3.92 μm laser performance and interionic dynamics of the dual-wavelength pumping system in holmium-doped InF3 fibers.

The work is devoted to obtaining of transparent nanocomposite materials as low loss, highly thermally conductive materials for potential laser applications. We report Ho3+:Y2O3–MgO nanocomposite ceramics with excellent mechanical and optical properties by combining glycine-nitrate process and spark plasma sintering. Morphology, structural-phase state, infrared transmittance and luminescence depending on the holmium concentration (0–12 at.%) were studied for the first time. It was found that optical transmittance reaches 75%@6000 nm for 3 at.% Ho3+:Y2O3–MgO ceramics. The absorption cross-section at 1931 nm and the emission cross-section at 2118 nm were determined to be σabs = 0.51 × 10−20 cm2 and σem = 0.29 × 10−20 cm2, respectively. Based on the testing results of luminescent characteristics it was demonstrated that Ho3+:Y2O3–MgO nanocomposite is a promising material for high-power eye-safe lasers operating in the 2 μm wavelength range.

OBJECTIVE: To investigate the mechanism of stone dusting in Holmium (Ho): YAG laser lithotripsy (LL). MATERIALS AND METHODS: Cylindrical BegoStone samples (6 × 6 mm, H × D) were treated in water using a clinical Ho:YAG laser lithotripter in dusting mode (0.2–0.4 J with 70–78 μs in pulse duration, 20 Hz) at various fiber tip to stone standoff distances (SD = 0, 0.5, and 1 mm). Stone damage craters were quantified by optical coherence tomography and bubble dynamics were captured by high-speed video imaging. To differentiate the contribution of cavitation vs thermal ablation to stone damage, three additional experiments were performed. First, presoaked wet stones were treated in air to assess stone damage without cavitation. Second, the laser fiber was advanced at various offset distances (OSD = 0.25, 1, 2, 3, and 10 mm) from the tip of a flexible ureteroscope to alter the dynamics of bubble collapse. Third, stones were treated with parallel fiber to minimize photothermal damage while isolating the contribution of cavitation to stone damage. RESULTS: Treatment in water resulted in 2.5- to 90-fold increase in stone damage compared with those produced in air where thermal ablation dominates. With the fiber tip placed at OSD = 0.25 mm, the collapse of the bubble was distracted away from the stone surface by the ureteroscope tip, leading to significantly reduced stone damage compared with treatment without the scope or with scope at large OSD of 3–10 mm. The average crater volume produced by parallel fiber orientation at 0.2 J after 100 pulses, where cavitation is the dominant mechanism of stone damage, was comparable with those produced by using perpendicular fiber orientation within SD = 0.25–1 mm. CONCLUSION: Cavitation plays a dominant role over photothermal ablation in stone dusting during short pulse Ho:YAG LL when 10 or more pulses are delivered to the same location.

Objective Laser technology in urology is currently used for both stone lithotripsy and prostate enucleation. Thulium fiber laser (TFL) is a novel laser, with initial studies showing potential benefits over other lasers both in terms of its effectiveness and safety profile. Material and methods In the first part of this review, a descriptive analysis of the theoretical concepts behind TFL was performed. This part focused on the physics and laser parameters as applied to the clinical practice. These were interpreted in the context of other lasers, namely, the Holmium:YAG laser to highlight the theoretical advantages as well as potential pitfalls offered by the TFL. In the second part of the review, a narrative synthesis of in-vitro studies regarding TFL and its modifications is performed assessing stone-related parameters, namely, ablation rate, operative time retropulsion, and safety. Results TFL achieved high ablation rates in most studies and performed better than Holmium:YAG laser across a range of different settings and ablation modes when the two lasers were compared. Moreover, its ability to use low pulse energy ensures minimal stone retropulsion with the retropulsion threshold estimated to be 2-4 times higher than that of Holmium:YAG laser. From a safety viewpoint, TFL poses no additional risks than other lasers, although it does potentially lead to slightly higher temperatures in the surrounding tissues during lithotripsy. Conclusion The unique properties of TFL have made it an attractive alternative to conventional laser techniques currently used in urology. Clinical studies are required before its application can become more widespread.

Incorporeal lithotripsy by using holmium:YAG laser has been recently successfully spread and used in the treatment of urolithiasis. Although this method is not as common in salivary gland surgery, it is also recommended for endoscopic treatment of sialolithiasis. In this study, we decided to analyse effectiveness of holmium:YAG laser method among patients with midsize stones as the treatment in this particular population is still not determined and remains in dispute. Thus, the primary aim of the study is a prospective, complex analysis of incorporeal holmium:YAG laser lithotripsy effectiveness and safety in patients suffering from sialolithiasis. The examined group consisted of 32 consecutive patients, 17 female (53%) and 15 male (47%). The average age was 42 (age range 22–70). In our series, sialoendoscopy with intraductal lithotripsy was performed in patients with wide range of stone’s diameter (3 to 10 mm). The calculi were removed with foreign body forceps or retrieval basket, after stone fragmentation with holmium:YAG laser. The power of the laser during surgery was set at 2.5 to 3.5 W. One shot energy equalled 0.5–0.7 J with frequency of 5 Hz. The bivariate Pearson Correlation and a point-biserial correlation were used to analyse the data. Total success rate of holmium:YAG laser lithotripsy in this consecutive group was equal to 90% and efficacy in the group with excluded cases when endoscopic approach difficulties were experienced (stone not visible) reached 93%. The long-term follow-up revealed that in 26 patients (84%), complete recovery was achieved. Two patients developed Wharton’s duct stenosis and one Stensen’s duct orifice stenosis (9.5%), of whom one required reoperation. Two patients eventually underwent total excision of submandibular gland. Sialoendoscopy combined with incorporeal laser-assisted lithotripsy proved to be effective and safe method for treatment of sialothiasis with midsize stones (4–8 mm) in population of clinic. Even taking into account the prevalence of complications associated with holmium:YAG laser, it is still safer alternative compared to open surgery where there is a significant risk of the bleeding, wound infection or injury of the facial nerve.

Introduction. Urolithiasis is one of the most common pathologies in modern urology. This disease is registered in 10% of the population and is manifested by an annual increase. Despite all the effectiveness and safety of Ho:YAG, in recent years, the thulium laser has attracted more and more interest. At the moment, in the modern literature there is not enough information about thulium and holmium ureterolithotripsy. The aim of this study is to compare the effectiveness of thulium and holmium ureterolithotripsy. Material and Methods. Since from October 2018 to October 2019 in City Centre Endoscopic Urology and New Technologies Clinical Hospital of St. Luke; St. Petersburg, 420 patients underwent contact ureterolithotripsy with using of thulium (group Б) or holmium (group А) lasers for calculi localized in the ureter. Results. Patients in group B had an advantage in terms of such indicators as the time of surgery, the time of lithotripsy in the Dusting and Fragmentation modes for ureteral calculi of any localization compared with group A. The SFR level in the two groups was relatively identical. Patients in group B had a lower rate of retropulsion during lithotripsy compared to patients in group A. And also in group B there was no migration of calculus into the renal cavity system. Conclusion. Our data indicate the same level of stone free rate when using both thulium and holmium lasers in the dusting and fragmentation modes. However, there is a higher efficiency during ureterolithotripsy using a thulium laser compared to ureterolithotripsy using a holmium laser, regardless of the lithotripsy mode.

Objective: To analyze the long-term efficacy and safety of holmium laser enucleation of the prostate (HoLEP) for benign prostatic hyperplasia. Materials and Methods: A total of 127 patients who und...

A mode-locked Thulium-Holmium doped fiber laser (THDFL) with a Germanium Selenide (GeSe) saturable absorber (SA) is demonstrated for operation in the 2.0 μm wavelength region. The SA device is fabricated by drop-casting the GeSe onto an arc-shaped fiber which is then incorporated into the THDFL to induce mode-locked pulses. Stable mode-locking is attained at 1908.78 nm, with pulse duration of 1.67 ps and output power of 2.74 mW at a maximum pump power of 476 mW. The results of this work show that the GeSe can be a viable alternative for ultrafast photonics applications in the 2.0 μm. region.

Summary High saturation magnetization, hysteresis-less long linear response range, and resistance to device fabrication conditions are figures of merit for magnetic materials. Despite advances in materials research, many high-saturating micro- and nanomagnetic materials are hysteresis-prone, have short linear ranges, and are sensitive to oxidation, resulting in device inefficiencies in high-frequency electronics and unpredictable responses in magnetic sensing applications. Holmium oxide is a promising material because of its high magnetic susceptibility, but synthetic options are limited, with low-temperature magnetism incompletely characterized. Here, we present physical vapor deposition synthesis and material characterization of polycrystalline holmium oxide thin films. The product has saturation magnetization exceeding 2 Tesla, linear range (μ0H) also exceeding 2 Tesla, zero magnetic remanence and coercivity, and resistance to harsh processing conditions including oxygen plasma and concentrated hydrofluoric acid etching, making these thin films ideal for fabricating next-generation nanoscale magnetic devices in advanced scientific and engineering applications.

Purpose: We performed in vitro studies to assess the relationship of pulse frequency on stone ablation during contact laser lithotripsy and determine if there is a threshold after which its effect ...

Purpose To evaluate the safety and feasibility of same-day treatment, including the simulation procedure for assessment of intrahepatic and extrahepatic distribution of the microspheres, with holmium-166 (166Ho)-radioembolization. Materials and Methods This was a secondary analysis of patients included in the 4 prospective studies (HEPAR I, HEPAR II, HEPAR PLuS, and SIM) on 166Ho-radioembolization. The technical success rate of the same-day treatment protocol, defined as the number of patients who completed the same-day treatment, was measured. Total in-room time, duration of the scout procedure, time to imaging, and duration of the treatment procedure were recorded. Reasons for discontinuation or adjustment of treatment were identified. Adverse events that occurred during the treatment day were recorded. Results One hundred five of 120 scheduled patients completed the same-day treatment with 166Ho-radioembolization (success rate, 88%). After the simulation procedure, treatment was cancelled in 15 patients because of extrahepatic deposition (n = 8), suboptimal tumor targeting (n = 1), unanticipated vascular anatomy (n = 5), and dissection (n = 1). In another 14 patients, the treatment plan was adjusted. The median total procedure time (ie, simulation, imaging, and treatment) was 6:39 hours:minutes (range, 3:58–9:17 hours:minutes). Back pain was a major same-day treatment-related complaint (n = 28). Conclusion 166Ho-radioembolization as a same-day treatment procedure is feasible in most selected patients, although treatment was adjusted in 12% of patients and cancelled in 12% of patients. This approach might be beneficial for a select patient population, such as patients needing a radiation segmentectomy.

Purpose The objective of this study was to investigate whether the use of an anti-reflux catheter improves tumor targeting for colorectal cancer patients with unresectable, chemorefractory liver metastases (mCRC) treated with holmium-166 (166Ho)-radioembolization. Materials and methods In this perspective, within-patient randomized study, left and right hepatic perfusion territories were randomized between infusion with a Surefire® anti-reflux catheter or a standard microcatheter. The primary outcome was the difference in tumor to non-tumor (T/N) activity distribution. Secondary outcomes included the difference in infusion efficiency, absorbed doses, predictive value of 166Ho-scout, dose-response relation, and survival. Results Twenty-one patients were treated in this study (the intended number of patients was 25). The median T/N activity concentration ratio with the use of the anti-reflux catheter was 3.2 (range 0.9–8.7) versus 3.6 (range 0.8–13.3) with a standard microcatheter. There was no difference in infusion efficiency (0.04% vs. 0.03% residual activity for the standard microcatheter and anti-reflux catheter, respectively) (95%CI − 0.05–0.03). No influence of the anti-reflux catheter on the dose-response rate was found. Median overall survival was 7.8 months (95%CI 6–13). Conclusion Using a Surefire® anti-reflux catheter did not result in a higher T/N activity concentration ratio in mCRC patients treated with 166Ho-radioembolization, nor did it result in improved secondary outcomes measures. Trial registration clinicaltrials.gov identifier: NCT02208804

Purpose Urinary stones can be successfully treated using a Holmium: Yttrium-Aluminum-Garnet (Ho: YAG) laser. Regarding success rates, laser pulse energy, frequency, and pulse width are well-known contributing factors. Whether the pulse shape might be a further factor influencing the laser efficiency is unclear. This study aimed to evaluate different modes of laser pulse shapes in a real-world setting. Materials and methods The Dornier Medilas® H Solvo (Wesling, Germany) was used in the treatment of ureter and kidney stones. Patients were randomized into standard pulse shape (SPS) and new pulse shape groups (NPS1; ureter) and (NPS2; kidney pelvis), depending on the stone localization. The primary endpoint was laser efficiency defined as mm³ stone destruction per overall operating time. Secondary endpoints encompassed number of stone recoveries and stone-free rate. Results Altogether 145 patients (24 SPS vs. 32 NPS1; 51 SPS vs. 38 NPS2) were included. No differences in sex, age, body mass index, stone localization and stone composition were found, except for preoperative stone size (133±95 [SPS] vs. 197±139 [NPS1] mm³; p=0.023) and (348±298 [SPS] vs. 525±429 [NPS2] mm³; p=0.042). Regarding the primary endpoint, a significant increase in laser efficiency could be detected for the NPS1 and NPS2 groups compared to the SPS groups (39.9±44.9 vs. 28.8±30.2 and 51.7±61.3 vs. 22.4±24.2 mm³/min [mean±standard deviation]). No statistically significant differences were found for secondary endpoints and perioperative complication rates. Conclusions Efficiency of the Ho: YAG laser can be positively influenced by different pulse shapes. This adds the variable of individualized intraoperative decision making.

Background To compare the diagnostic value of prostate cancer (PCa) between holmium laser enucleation of the prostate (HoLEP) and transurethral resection of the prostate (TURP). Methods We retrospectively analyzed the clinical data of 2909 patients who underwent surgery for benign prostatic hyperplasia (BPH) from January 2008 to June 2018. A total of 1362 patients received HoLEP, and 1547 patients received TURP. The baseline patient characteristics were collected. We then compared the perioperative outcomes of these patients who diagnosed with incidentally diagnosed prostatic carcinoma (IDPC) or PCa after BPH surgeries. Results The total detection rate of PCa in HoLEP group was higher than that in TURP group (85/6.24% vs. 61/3.94%, p = 0.005). Specifically, 55(4.6%) patients were diagnosed with IDPC in HoLEP group with prostate-specific antigen (PSA) less than 4 ng/ml, and 37(2.7%) patients in TURP group (p = 0.014). For the patients with PSA between 4 and 10 ng/ml, 15(13.9%) patients were diagnosed with PCa after HoLEP, and 6(5.0%) patients after TURP (p = 0.023). But the detection rate of PCa was not significantly different between the two groups when PSA was over 10 ng/ml. On the other hand, 57 in 1215 patients with no prostate biopsy preoperatively were diagnosed with PCa after HoLEP, while 42 in 1370 patients after TURP (4.7% vs. 3.1%, p = 0.040), respectively. Twenty-six patients received once biopsy and diagnosed with PCa in HoLEP group, while 15 patients in TURP group (18.4% vs. 8.9%, p = 0.018), respectively. However, no significant difference was observed for patients who received twice prostate biopsy in the two groups. Conclusions The present study showed that HoLEP can provide a higher total detection rate of PCa when compared with TURP. Besides, this superiority was especially embodied in patients with PSA less than 10 ng/ml.

Moses™ technology has been developed to improve holmium laser fragmentation at 1–2 mm distance from the stone. Because popcorn lithotripsy is a non-contact technique, we compared short pulse (SP) and Moses distance (MD) modes in an in vitro model. BegoStones were fragmented using a 120 W Ho:YAG laser (P120 Moses) and a 230 μm core fiber introduced through a ureteroscope. 20 W (1 J × 20 Hz; 0.5 J × 40 Hz) and 40 W (1 J × 40 Hz; 0.5 J × 80 Hz) settings (total energy 4.8 kJ) were tested using SP and MD modes. We assessed fragment size distribution and mass lost in fluid (initial mass–final dry mass of all sievable fragments). High-speed video analysis of fragmentation strike rate and vapor bubble characteristics was conducted for 1 J × 20 Hz and 0.5 J × 80 Hz. Laser strike rate (number of strikes divided by frequency) was categorized as: (1) direct—a visual plume of dust ejected from stone while in contact with fiber tip; (2) indirect—a visual plume of dust ejected with distance between stone and fiber tip. For 1 J × 20 Hz (20 W), MD resulted in more mass lost in fluid and a lower distribution of fragments ≥ 2 mm compared to SP (p

A MAX phase Ti3AlC2 thin film is demonstrated as a saturable absorber (SA) to induce Q-switching in the 2.0 μm region. The Ti3AlC2 thin film is sandwiched between two fiber ferrules and integrated into thulium doped fiber laser (TDFL) and thulium-holmium doped fiber laser (THDFL) cavities. Stable Q-switched pulses are observed at 1980.79 nm and 1959.3 nm in the TDFL and THDFL cavities respectively, with repetition rates of 32.57 kHz and 21.94 kHz and corresponding pulse widths of 2.72 μs and 3.9 μs for both cavities. The performance of the Ti3AlC2 based SA for Q-switching operation indicates the high potential of other MAX phase materials to serve as SAs in future photonics systems.

The increasing demand for large-scale integrated logic systems urges the development of multireadout molecular logic gates. Especially, it is of great significance to explore dual-readout logic devices with both fluorescence (FL) and magnetic resonance (MR) signals as measurable outputs, since the signal combination of FL/MR might render molecular logic devices better practicality in biomedical applications. In this study, holmium(III)-doped carbon nanodots (Ho-CDs), which exhibited pH-responsive behaviors in both FL and MR signals, were synthesized by a facile one-pot pyrolysis method. When triggered by H

Objective To investigate the effects of laser temporal pulse shaping of the super-pulse thulium fibre laser (SPTFL) and to compare these in controlled in vitro conditions with various holmium: yttrium aluminium garnet (Ho:YAG) pulse delivery modes. Materials and methods The SPTFL (Urolase SP, IRE-Polus, Fryazino, Russia), with an emission wavelength of 1.94 μm, and a Ho:YAG laser (P120H; Lumenis, Yokneam, Israel) with Moses technology were compared. Pulse shape, stone retropulsion and ablation efficiency were evaluated using BegoStones and compared for each laser mode: short (SP), long (LP), and Moses pulse (MP) for Ho:YAG, regular pulse (RP) and dual pulse (DP) for SPTFL. Results The Ho:YAG SP mode exhibited an asymmetrical pulse shape, with a steep leading slope and a much more gradual trailing slope, without any flat section. Pulses generated by the SPTFL were significantly longer and therefore had lower peak power than those generated by the Ho:YAG laser at equivalent energy settings. Retropulsion for the holmium:YAG LP and MP modes was similar and lower than that for the SP mode, but higher than for the SPTFL (all P ≤ 0.02), with an average stone displacement approximately four times and two times lower for SPTFL as compared to the Ho:YAG laser. Comparison of ablation volumes indicated that the SPTFL induced significantly higher (twofold) ablation than the Ho:YAG laser. Conclusions The magnitude and initial velocity of stone retropulsion decreased with longer pulse duration and lower pulse peak power, without sacrificing ablation efficiency. These observations are manifest when comparing the Ho:YAG laser with the SPTFL. The novel SPTFL provides greater versatility and control of pulse variables than the Ho:YAG laser. Further clinical investigation of practical benefits achievable with pulse-shaping SPTFL modes is warranted.

In this article, for the first time, an efficient multi-wavelength fiber laser based on a Tm:Er:Yb:Ho co-doped germanate glass, optically pumped at 980 nm wavelength and simultaneously emitting at 1550 nm, 1800 nm and 2050 nm wavelengths, is designed and optimized. An exhaustive model, taking into account the energy transfer phenomena between different rare earths, is developed. The device behavior is investigated by means of several parametric sweeps with respect to the input pump power, the fiber length, the dopant concentrations and the output mirrors reflectivities. Four optimal concentrations have been found by means of a home-made computer code based on particle swarm optimization (PSO) approach, allowing a global solution search. These concentrations allow levels of output powers very close to each other, equal to 20 mW $\pm$ 0.1 $\%$ at 1550 nm, 1800 nm and 2050 nm, respectively. These results predict the possibility of tailoring the dopant concentrations in order to construct broadband optical sources with similar emission powers at multiple wavelengths and broadband amplifiers.

Holmium:YAG(Ho:YAG) is currently the standard for lithotripsy. Superpulsed Thulium Fiber Laser(TFL) has been evaluated as an alternative for lithotripsy, using laser fibers with core-diameters(CDF) down to 50 µm and additional available settings suitable for “dusting” technique. This in-vitro study compared ablation rates, fissures and fragments’ size with 150µmCDF or 272µmCDF with different laser settings using TFL and Ho:YAG. 150CDF and 272CDF were compared using three settings for TFL “fine dusting”(FD:0.15 J/100 Hz); “dusting”(D:0.5 J/30 Hz); “fragmentation”(Fr:1 J/15 Hz) and Ho:YAG(D and Fr). An experimental setup consisting of immerged 10 mm cubes of artificial hard(H) or soft(S) stone phantoms was used with a 20 s’ lasing time and a spiral trajectory, in contact mode. Fragments (acquired through sieves) and stones were observed under optical microscopy before three-dimensional scanning to measure fragments and fissures(DOF) mean diameters and ablation volumes. Ablation volumes in with 150CDF-TFL and 272CDF-TFL were higher than those for 272CDF-Ho:YAG in both “dusting” (twofold and threefold) and “fragmentation”(1,5-fold and twofold). “Fine dusting” ablation rates with 150CDF-TFL and 272CDF-TFL were respectively at least 1,5-fold and twofold higher than those for 272CDF-Ho:YAG in “dusting”. 150CDF produced significantly smaller DOF than 272CDF in all settings against S and H except in fragmentation. 150CDF produced lower fragments’ diameter than 272CDF in all settings except dusting. These preliminary studies demonstrate that at equal settings and CDF, TFL ablation rates are at least two-fold higher than those with Ho:YAG. 150CDF produces smaller fissures and fragments (that meets the definition of “dusting” lithotripsy) than 272CDF and higher ablation volumes than Ho:YAG.

Objective To compare the efficacy and safety of miniature semi-rigid ureteroscopy (URS) with holmium (Ho)-yttrium-aluminium-garnet (YAG) laser lithotripsy vs shockwave lithotripsy (SWL) for treating upper urinary tract (UUT) calculi >1 cm in children. Patients and methods Children with unilateral single UUT ureteric stones of >1 cm were prospectively enrolled in this study. Patients were randomly divided into two groups: Group 1, treated with SWL; and Group 2, treated with URS (6/7.5 F) and laser lithotripsy. The patients’ characteristics, stones demographics, operative time, adjunctive procedures, stone-free rate (SFR), re-treatment rate, and complications were statistically analysed and compared. Success was defined as stone-free status (no stone residual of ≥0.3 cm) at 1 month from the initial treatment without any auxiliary procedures. Results In all, 68 patients with UUT stones met our inclusion criteria. There were no significant differences between the two groups for patient or stone demographics. In Group 1, the SFR was 26/34 (76.4%) and in Group 2 it was 33/34 (97.1%) (P = 0.03). A total of 12 auxiliary procedures in Group 1 and two in Group 2 were needed to reach a 100% SFR (P = 0.014). There were no significant differences between the two groups for operative times, adjunctive procedures, number of complicated cases or complications of Grade ≥III (P = 0.65, P = 0.23, P = 0.77, and P = 0.62, respectively). Conclusion Miniature semi-rigid URS with Ho-YAG laser lithotripsy for UUT ureteric stones of >1 cm in children was more effective than SWL in terms of SFR and re-treatment rate, with no significant difference in the rate or grade of complications. Abbreviations EQ: efficiency quotient; KUB: plain abdominal radiograph of the kidneys, ureters and bladder; RCT: randomised controlled trial; SFR: stone-free rate; SWL: shockwave lithotripsy; URS: ureteroscopy; US: ultrasonography/ultrasound; URS: ureteroscopy; UUT: upper urinary tract; YAG: yttrium-aluminium-garnet

PURPOSE OF REVIEW To update laser lithotripsy advances in regard to new laser types and technologies as well as review contemporary laser safety concerns. RECENT FINDINGS The high prevalence of urolithiasis and the continuing miniaturization of scopes has encouraged the growth of laser lithotripsy technology. The holmium:yttrium-aluminum-garnet (Ho:YAG) laser has been used for over 20 years in endourology and has been extensively studied. Holmium laser power output is affected by a number of factors, including pulse energy, pulse frequency, and pulse width. Several recent experimental studies suggest that the new dual-phase Moses 'pulse modulation' technology, introduced in high-power laser machines, carries a potential to increase stone ablation efficiency and decrease stone retropulsion. A newly introduced thulium fiber laser (TFL) has been adapted to a very small laser fiber size and is able to generate very low pulse energy and very high pulse frequency. Both of these technologies promise to play a larger role in laser lithotripsy in the near future. However, more experimental and clinical studies are needed to expand on these early experimental findings. Even though laser lithotripsy is considered safe, precautions should be taken to avoid harmful or even catastrophic adverse events to the patient or the operating room staff. SUMMARY The Ho:YAG laser remains the clinical gold standard for laser lithotripsy for over the last two decades. High-power Ho:YAG laser machines with Moses technology have the potential to decrease stone retropulsion and enhance efficiency of laser ablation. The new TFL has a potential to compete with and perhaps even replace the Ho:YAG laser for laser lithotripsy. Safety precautions should be taken into consideration during laser lithotripsy.

The purpose is to present our preliminary results where ultra-mini PCNL (UMPCNL) with the new 120-watt laser with the anti-retropulsion (Lumenis® MOSES Pulse™120H Holmium: YAG laser) was used for the first time to our knowledge. Twelve patients underwent ultra-mini PCNL in prone position under general anesthesia using a 12-F nephroscope with a 14-F Access sheath in our tertiary center. The fragmentation was performed with a 500 μm laser fiber using the 120-watt Lumenis® MOSES Pulse™120H Holmium: YAG laser). Efficacy was considered in terms of stone-free rates (SFR), complication rate, duration of the operation, and hospital stay. Our SFR was 91.6% with 11 patients out of 12 being completely free of any residual stone. The duration of the operation was 86.4 ± 36.8 (40-165) min, whereas the mean laser time (real stone fragmentation laser time) was 755.7 ± 954.7(241-3425) sec. The total laser energy used was 39.7 ± 52 KJoules (11.3-182). The fluoroscopy time and radiation doses were 358.5 ± 180.4 (154-750) sec and 64.7 ± 41.2 (14.7-159.0) mGy, respectively. The mean reduction in levels of hemoglobin postoperatively was 0.6 ± 0.3 (0.1-0.9) g/dL, and no complications were observed. The combination of UMPCNL with the new 120-watt laser and the unique anti-retropulsion technology (Lumenis® MOSES Pulse™120H Holmium: YAG laser) delivered very promising results and it could be the future of PCNL.

Purpose: To evaluate the factors affecting the effectiveness, safety, and success of retrograde holmium:yttrium–aluminum–garnet laser endopyelotomy as the primary treatment of ureteropelvic junction obstruction in adults. Methods: Adult patients who underwent retrograde holmium:yttrium–aluminum–garnet laser endopyelotomy as the primary treatment of ureteropelvic junction obstruction between January 2012 and June 2016 at our clinic were retrospectively analyzed. Success was defined as the relief of symptoms and the resolution of obstruction, as assessed via radiography. Factors affecting success were analyzed, such as the clinical characteristics, procedural outcomes, complications, and the type of ureteroscopy used in the procedure. Results: Procedural success was achieved in 29 (74.4%) out of 39 patients, with a mean age of 38.3 ± 12.3 years during a median follow-up duration of 44 (33–65) months. Failure occurred at a median of 4.5 (3–22) months. It was detected that the presence of primary obstruction, ipsilateral kidney function being >30% of normal, and the length of obstruction being Conclusion: Retrograde holmium:yttrium–aluminum–garnet laser endopyelotomy is a minimally invasive method that can be used effectively and safely as the primary treatment of patients with ureteropelvic obstruction, when long-term results are also taken into consideration. The decision of performing laser endopyelotomy should be made after a detailed evaluation of the characteristics of the patient as well as of the obstruction.