Arterial pseudoaneurysm: a rare complication following laser lithotripsy-case series and literature review.

OBJECTIVE: To perform a comprehensive narrative review that will examine the risk factors and treatment outcomes of arterial pseudoaneurysm following laser flexible ureteroscopy (F-URS). METHODS: A retrospective case series and a review of literature was performed. Clinical records from three patients treated for postoperative arterial pseudoaneurysm from January of 2021 to November 2023 were identified. A comprehensive literature review was also performed. The MEDLINE and Scopus databases were searched. The analysis was made by a narrative synthesis. RESULTS: Three cases of postoperative arterial pseudoaneurysm were included, one from our center, one from Dubai, UAE, and one from Barcelona. The literature review identified six case reports, two after endocorporeal laser lithotripsy with thulium fiber laser (TFL) and four with Ho:YAG laser. All cases, from our series and literature review, presented with macroscopic hematuria and used high-power laser settings. All cases were treated by selective embolization. CONCLUSION: Ho:YAG or TFL lasers are both capable of causing arterial pseudoaneurysms following F-URS if high-power settings are used. Selective artery embolization continues to be the treatment of choice with good outcomes.

Illumination matters part I: comparative analysis of light sources and illumination in flexible ureteroscopy-fundamental findings from a PEARLS analysis.

PURPOSE: Illumination characteristics of flexible ureteroscopes have been evaluated in air, but not in saline, the native operative medium for endourology. The aim was to evaluate light properties of contemporary ureteroscopes in air versus saline, light distribution analysis, and color temperature. METHODS: We evaluated the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, and OTU WiScope using a 3D printed black target board in-vitro model submerged in saline. A spectrometer was used for lux and color temperature measurements at different opening locations. RESULTS: Illuminance was higher in saline compared to air (5679 vs. 5205 lx with Flex-Xc, p = 0.02). Illuminance in saline differed between ureteroscopes (ANOVA p < 0.001), with highest for the Flex-Xc at 100% brightness setting (5679 lx), followed by Pusen 9.2F (5280 lx), Flex-X2s (4613 lx), P7 (4371 lx), V3 (2374 lx), WiScope (582 lx) and finally Pusen 7.5F (255 lx). The same ranking was found at 50% brightness setting, with the highest ureteroscope illuminance value 34 times that of the scope with lowest illuminance. Most scopes had maximum illuminance off center, with skewness. Three scopes had two light sources, with one light source for all other scopes. Inter-scope comparisons revealed significant differences of color temperature (ANOVA p < 0.001). CONCLUSION: The study demonstrates the presence of inhomogeneous light spread as well as large differences in illumination properties of ureteroscopes, possibly impacting on the performance of individual scopes in vivo. Additionally, the study suggests that future studies on illumination characteristics of flexible ureteroscopes should ideally be done in saline, and no longer in air.

Could Use of a Flexible and Navigable Suction Ureteral Access Sheath Be a Potential Game-changer in Retrograde Intrarenal Surgery? Outcomes at 30 Days from a Large, Prospective, Multicenter, Real-world Study by the European Association of Urology Urolithiasis Section.

BACKGROUND AND OBJECTIVE: The aim of this study was to evaluate the stone-free status (SFS) rate and complications after flexible ureteroscopy (fURS) for treatment of renal stones using a flexible and navigable suction (FANS) ureteral access sheath. METHODS: Data for adults undergoing fURS in 25 centers worldwide were prospectively collected (August 2023 to January 2024). Exclusion criteria were abnormal renal anatomy and ureteral stones. All patients had computed tomography scans before and within 30 d after fURS with a FANS ureteral access sheath. SFS was defined as follows: grade A, zero fragments; grade B, a single fragment ≤2 mm; grade C, a single fragment 2.1-4 mm; and grade D, single/multiple fragments >4 mm. Data for continuous variables are presented as the median and interquartile range (IQR). Multivariable logistic regression was performed to evaluate predictors of grade A SFS. KEY FINDINGS AND LIMITATIONS: The study enrolled 394 patients (59.1% male) with a median age of 49 yr (IQR 36-61). The median stone volume was 1260 mm3 (IQR 706-1800). Thulium fiber laser (TFL) was used in 45.9% of cases and holmium laser in the rest. The median lasing time was 18 min (IQR 11-28) and the median operative time was 49 min (IQR 37-70). One patient required a blood transfusion and 3.3% of patients had low-grade fever. No patient developed sepsis. Low-grade ureteral injury occurred in eight patients (2%). The grade A SFS rate was 57.4% and the grade A + B SFS rate was 97.2%, while 2.8% of patients had grade C or D SFS. Eleven patients underwent repeat fURS. Multivariable analysis revealed that a stone volume of 1501-3000 mm3 (odds ratio 0.50) and of >3000 mm3 (odds ratio 0.29) were significantly associated with lower probability of grade A SFS, while TFL use was associated with higher SFS probability (odds ratio 1.83). Limitations include the lack of a comparative group. CONCLUSIONS AND CLINICAL IMPLICATIONS: fURS using a FANS ureteral access sheath resulted in a high SFS rate with negligible serious adverse event and reintervention rates. PATIENT SUMMARY: We looked at 30-day results for patients undergoing telescopic laser treatment for kidney stones using a special type of vacuum-assisted sheath to remove stone fragments. We found a high stone-free rate with minimal complications.

Ureteral stents: What your eyes can't see! An in vitro study.

OBJECTIVES: To characterize and compare in vitro the surfaces of ureteral stents (STENTS) before utilization. METHODS: Our in vitro experiment included six unused STENTS models: three double-pigtail with side orifices (ImaJin and Stenostent [Coloplast©,France], TriaSoft [BostonScientific©,USA]), two double-pigtail without side orifice (Vortek-TumorStent [Coloplast©,France], Urosoft-TumorStent [Bard-Angiomed©,Germany]) and one single-pigtail (J-Fil [Rocamed©,Monaco]). STENTS were made of polyurethane except for ImaJin (silicone). For all STENTS, four parts of the stent were specifically analyzed under high-resolution scanning electron microscopy (HR-SEM,FEI-XL40 [Philips©,France]): surface core, lateral orifice, ureteral loop, and black marking surface. Each experiment was repeated with three different samples from three different stents. STENTS analysis included multiple imperfection searches, defined as irregularities>10µm. RESULTS: All STENTS presented imperfections with no discernible differences. Imperfections were mainly located on the stent loop and on the lateral orifice. For STENTS without side orifice (J-Fil, Urosoft) imperfections were also reported, on the beveled cut as well as the distal loop orifice. Marking surfaces examinations found defects in the Urosoft and imperfections in the ImaJin and Stenostent. The Triasoft presented a better smoothness on marking surfaces compared to other STENTS. Additional matter was reported on the loop distal orifice for J-Fil and ImaJin but all STENTS presented irregular cross-sectional aeras. CONCLUSION: All ureteral stents are not perfectly smooth even before utilization. Imperfections were noticed regardless to stent composition or shape, and could play a role in the incrustation phenomenon, is association with inner irregularities, infection, and urine composition. Both manufacturing and material could have an impact on the stent external surface's smoothness.

Ureteroscopic management in cystinuric patients: long-term results from a tertiary care referral center.

OBJECTIVE: To evaluate long-term surgical and functional outcomes of cystinuric patients exclusively treated with Ureteroscopy (URS). METHODS: Data from patients treated for cystine stones at a single academic center were retrospectively analyzed. The management protocol consisted of (i) treating symptomatic or > 7 mm stones, (ii) multi-staged URS for voluminous stones, (iii) referring patients to a dedicated nephrological clinic. The eGFR was calculated according to the MDRD formula. CKD category was assessed according to the NKF classification. Relevant CKD was defined as CKD category ≥ 3a. Descriptive statistics were used to analyze the cohort data. RESULTS: Data from 46 cystinuric patients treated with 332 URS were available. Median age at diagnosis and at first URS in our center were 18 and 32 years, respectively. Median follow-up was 101 months. Median number of URS and recurrences per patient were 6 and 2, respectively. The median interval between the first and the last available creatinine level was 64 months. Median first and last eGFR were 72 and 74 mL/min, respectively. Overall, 83% of patients had stable or improved renal function within the study period. Ureteral stricture occurred in 3 (6.5%) patients. CONCLUSIONS: Cystinuria requires intensive endoscopic management. Most patients treated with URS have stable or improved renal function within a long-term follow-up. CKD is a not neglectable event that potentially occurs at an early stage of life. Current findings should be considered for the surgical management of cystinuric patients.

Is "Kidney Stone Calculator" efficient in predicting ureteroscopic lithotripsy duration? A holmium:YAG and thulium fiber lasers comparative analysis.

PURPOSE: This study aimed to evaluate the ability of Kidney Stone Calculator (KSC), a flexible ureteroscopy surgical planning software, to predict the lithotripsy duration with both holmium:YAG (Ho:YAG) and thulium fiber laser (TFL). METHODS: A multicenter prospective study was conducted from January 2020 to April 2023. Patients with kidney or ureteral stones confirmed at non-contrast computed tomography and treated by flexible ureteroscopy with laser lithotripsy were enrolled. "Kidney Stone Calculator" provided stone volume and subsequent lithotripsy duration estimation using three-dimensional segmentation of the stone on computed tomography and the graphical user interface for laser settings. The primary endpoint was the quantitative and qualitative comparison between estimated and effective lithotripsy durations. Secondary endpoints included subgroup analysis (Ho:YAG-TFL) of differences between estimated and effective lithotripsy durations and intraoperative outcomes. Multivariate analysis assessed the association between pre- and intraoperative variables and these differences according to laser source. RESULTS: 89 patients were included in this study, 43 and 46 in Ho:YAG and TFL groups, respectively. No significant difference was found between estimated and effective lithotripsy durations (27.37 vs 28.36 min, p = 0.43) with a significant correlation (r = + 0.89, p < 0.001). Among groups, this difference did not differ (p = 0.68 and 0.07, respectively), with a higher correlation between estimated and effective lithotripsy durations for TFL compared to Ho:YAG (r = + 0.95, p < 0.001 vs r = + 0.81, p < 0.001, respectively). At multivariate analysis, the difference was correlated with preoperative (volume > 2000 mm3 (Ho:YAG), 500-750 mm3 SV and calyceal diverticulum (TFL)), operative (fragmentation setting (p > 0.001), and basket utilization (p = 0.05) (Ho:YAG)) variables. CONCLUSION: KSC is a reliable tool for predicting the lithotripsy duration estimation during flexible ureteroscopy for both Ho:YAG and TFL. However, some variables not including laser source may lead to underestimating this estimation.

A historical comparison of thulium fiber laser systems for stone lithotripsy: navigating toward safe and effective parameters.

INTRODUCTION AND OBJECTIVES: Medical device companies have introduced new TFL machines, including Soltive (Olympus, Japan), Fiber Dust (Quanta System, Italy), and TFLDrive (Coloplast, France). The primary objective of this study is to compare our initial clinical experiences with TFL using those devices. Through this historical comparison of Thulium Fiber Laser systems for stone lithotripsy, we aim to advance our understanding and approach toward achieving safe and effective TFL parameters. MATERIALS AND METHODS: The data for this comparative analysis were extracted from three distinct prospective series that were previously published, outlining our initial clinical experience with the Soltive (Olympus, Japan), FiberDust laser (Quanta System, Italy), and TFLDrive laser (Coloplast, France). Parameters such as stone size, stone density, laser-on time (LOT), and laser settings were meticulously recorded. Additionally, we assessed critical variables such as ablation speed (expressed in mm3/s) and Joules/mm3 for each lithotripsy procedure. RESULTS: A total of 149 patients were enrolled in this study. Among them, 120 patients were subjected to analysis concerning renal stones. Statistically significant differences were observed in the median (IQR) stone volume: 650 (127-6027) mm3 for TFLDrive, 1800 (682.8-2760) mm3 for Soltive, and 1125 (294-4000) mm3 for FiberDust (p: 0.007); while there were no differences regarding stone density among the groups. Significant variations were identified in median (IQR) pulse energy, frequency, and total power. The Soltive group exhibited lower energy levels (0.3 J vs. 0.6 J, p: 0.002) but significantly higher pulse frequency (100 Hz vs. 17.5 Hz, p: 0.003) and total power (24 W vs. 11W, p: 0.001) compared to the other groups. Laser-on time showed no substantial differences across all three groups. Additionally, a statistically significant difference was observed in median J/mm3, with the TFLDrive group using higher values (24 J/mm3, p: 0.001), while the Soltive group demonstrated a higher median ablation speed of 1.16 mm3/s (p: 0.001). The overall complication rate remained low for all groups, with comparable stone-free rates. CONCLUSION: By reducing pulsed frequency, we improved laser efficiency, but smaller volumes lead to decreased efficiency due to increased retropulsion and fragment movement. Further studies are needed to identify and establish the appropriate laser settings for this new technology.

Comparison of European and American Guidelines for Upper Tract Urothelial Carcinoma: How Are They different?

Urothelial carcinoma (UC) affecting the urinary tract is recognized as one of the prevalent types of cancer, ranking fifth in terms of incidence. However, it is important to note that upper tract urothelial carcinoma (UTUC), in comparison to bladder cancer, is relatively uncommon and represents a minority of UC cases, accounting for ∼5% to 10%. It is worth emphasizing that as much as 60% of UTUC cases are invasive at the time of diagnosis, in contrast to 25% of bladder cancer cases. These statistics highlight the urgent need for well-designed, multidisciplinary strategies to guide optimal management for this vulnerable patient population, aiming to control treatment variability and minimize the risks associated with undertreatment and overtreatment. Methods: In this study, we present a comparative analysis of the contemporary guidelines on UTUC management from the European Association of Urology (EAU) and the American Urological Association/Society of Urologic Oncology (AUA/SUO) released in 2023. Our objective is to contrast the different guidelines and examine the evidence on which their recommendations are based. Results: By thoroughly reviewing the guidelines from both organizations, we observed substantial agreement on the management of UTUC. However, we also identified noticeable differences among these guidelines, leading to a wide range of recommendations. These disparities might stem from variations in clinical practices, regional preferences, and the availability of resources. It is crucial to acknowledge that both the EAU and AUA/SUO base their guidelines on the latest scientific evidence and expert consensus within their respective regions. Conclusions: These findings underscore the importance of ongoing collaboration, knowledge exchange, and harmonization of guidelines to improve the standard of care for UTUC globally. Future research should focus on identifying areas of consensus and bridging the gaps between different international guidelines to enhance the management outcomes for this challenging disease.

Editorial letter to: Incidence of Ureteric Strictures Following Ureteroscopic Laser Lithotripsy: Holmium: YAG Versus Thulium Fiber Laser.

Dear Editor, The original paper by Ahmad Para S et al1 analyzed the incidence of ureteral strictures following holmium: yttrium aluminum garnet (Ho:YAG) and thulium fiber laser (TFL) endocorporeal laser lithotripsy (ELL) for ureteral stones. The authors should be commended for their work because this is the first prospective randomized controlled trial comparing the ureteric stricture rates between these 2 laser technologies for ELL. This study concluded that the TFL had a higher incidence of ureteral strictures than the Ho: YAG laser. Our editorial letter aims to clarify and highlight some key points.

Illumination matters Part III: Impact of light obstruction on illuminance from flexible ureteroscopes - a comparative PEARLS analysis.

PURPOSE: Artifacts from poor ureteroscopes' light design with shadowing and dark areas in the field of view have been reported. The aim was to quantify effects of light obstruction in a kidney calyx model. METHODS: We evaluated a series of contemporary flexible ureteroscopes including the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, as well as OTU Wiscope using an enclosed 3D-printed pink in vitro kidney calyx model submerged in saline, where the field of light was intentionally partially obstructed alternatively at 12, 3, 6, and 9 o'clock. A color spectrometer was used for illuminance measurements at a 45° opening position in the background of the model. RESULTS: Overall and mean background illuminance for each obstructive situation were significantly different between scopes for both 50% and 100% brightness settings (ANOVA p < 0.001). At 50% brightness setting, almost all scopes had their highest and lowest background illuminance with the 6 o'clock and 3 o'clock obstructive situation, respectively. At 100% brightness setting, these became 6 o'clock and 12 o'clock obstructive situations. Considering each obstructive situation individually, the Flex-Xc was consistently the scope with highest background illuminance and the Pusen 7.5F the lowest. Background illuminance for each obstructive situation varied significantly for each scope individually, with the greatest range of variability for Pusen 7.5F and V3. CONCLUSIONS: Illuminance performance of ureteroscopes within an obstructed calyx model differ significantly for various obstructive situations. Urologists should be aware of this to help guide their choice of ureteroscope.

How much energy do we need to ablate 1 cubic millimeter of stone during Thulium Fiber Laser lithotripsy? An in vitro study.

INTRODUCTION: Both Holmium:yttrium-aluminium-garnet (Ho:YAG) laser and Thulium Fiber Laser (TFL) can effectively treat all urinary stone types. This in vitro study evaluated the ablation volume per pulse (AVP) and required energy needed to ablate 1mm3 (RE, J/mm3) of various stone types at different laser settings with TFL. METHODS: 272-µm core-diameter laser fibers (Boston Scientific©) were connected to a 50 Watts TFL generator (IPG®). An experimental setup immerged human stones of calcium oxalate monohydrate (COM), uric acid (UA), and cystine (CYS) with a single pulse lasing emission (0.5/0.8/1 J), in contact mode. Stones were dried out before three-dimensional scanning to measure AVP and deduce from the pulse energy (PE) and AVP the RE. A direct comparison with known Ho:YAG's AVP and RE was then carried out. RESULTS: AVP for COM stones was significantly greater than those for CYS stones and similar to UA stones (p = 0.02 and p = 0.06, respectively). If AVP increased with PE against COM and UA stones, AVP decreased against CYS stones. 1 J PE resulted in a threefold lower RE compared with other PE for COM stones. On the contrary, RE for CYS increased with PE, whereas PE did not had influence on RE for UA. TFL was associated with greater AVP for COM, but lower for UA and CYS stones compared to Ho:YAG laser. CONCLUSION: This in vitro study firstly describes the ablation volume per pulse and required energy to treat a cubic millimeter of three frequent human stone types, and suggest TFL could not be suited for cystine. Therefore, stone composition could be considered when choosing the laser source for lithotripsy.

Thulium:YAG laser: a good compromise between holmium:YAG and thulium fiber laser for endoscopic lithotripsy? A narrative review.

PURPOSE: To provide a technological description of the new pulsed solid-state Thulium:YAG laser (Tm:YAG). In addition, current available literature on Tm:YAG lithotripsy is also reviewed. MATERIALS AND METHODS: Medline, Scopus, Embase, and Web of Science databases were used to search for Tm:YAG operating mode articles. RESULTS: Tm:YAG technology works with a laser cavity with thulium-doped YAG crystal, pumped by laser diodes. Laser beam operates at 2013 nm, with an adjustable peak power (≥ 1000 W) and the minimal fiber laser diameter is of 200 µm. It has an intermediate water absorption coefficient and peak power-pulse duration. Various pulse modulations are proposed, aiming to minimize stone retropulsion. Multiple comparative in vitro studies suggest that Tm:YAG's ability to fragment stones is similar to the one of the Ho:YAG laser; on the contrary, its ability to dust all stone types is similar to the one of the TFL, with a low retropulsion. A single in vivo study assessed Tm:YAG lithotripsy feasibility. CONCLUSIONS: The new pulsed solid-state thulium:YAG laser could represent a safe and effective compromise between Ho:YAG laser and TFL for endoscopic lithotripsy, either in retrograde intra-renal surgeries or in percutaneous nephrolithotomy.

Laser Ablation Efficiency, Laser Ablation Speed, and Laser Energy Consumption During Lithotripsy: What Are They and How Are They Defined? A Systematic Review and Proposal for a Standardized Terminology.

CONTEXT: Laser performance for lithotripsy is currently reported using units of measurement such as J/mm3, mm3/J, mm3/s, s/mm3, and mm3/min. However, there are no current standardized definitions or terminology for these metrics. This may lead to confusion when assessing and comparing different laser systems. OBJECTIVE: The primary objective was to summarize outcome values and corresponding terminology from studies on laser lithotripsy performance using stone volume in relation to time or energy. The secondary objective was to propose a standardized terminology for reporting laser performance metrics. EVIDENCE ACQUISITION: A systematic review of the literature was conducted using the search string ("j*/mm3" OR "mm3/j*" OR "mm3/s*" OR "s*/mm3" OR "mm3/min*" OR "min*/mm3" AND "lithotripsy") on Scopus, Web of Science, Embase, and PubMed databases. Study selection, data extraction, and quality assessment were performed independently by two authors. EVIDENCE SYNTHESIS: A total of 28 studies were included, covering holmium:yttrium-aluminum-garnet (Ho:YAG), MOSES, and thulium fiber laser (TFL) technologies. Laser energy consumption values reported for the studies ranged from 2.0 - 43.5 J/mm3in vitro and from 2.7 - 47.8 J/mm3in vivo, translating to laser ablation efficiency of 0.023 - 0.500 mm3/J and 0.021 - 0.370 mm3/J, respectively. Laser ablation speeds ranged from 0.3 - 8.5 mm3/s in vivo, translating to lasing time consumption of 0.12 - 3.33 s/mm3. Laser efficacy ranged from 4.35 - 51.7 mm3/min in vivo. There was high heterogeneity for the terminology used to describe laser performance for the same metrics. CONCLUSIONS: The range of laser performance metric values relating stone volume to energy or time is wide, with corresponding differing terminology. We propose a standardized terminology for future studies on laser lithotripsy, including laser ablation efficiency (mm3/J), laser ablation speed (mm3/s), and laser energy consumption (J/mm3). Laser efficacy (mm3/min) is proposed as a broader term that is based on the total operative time, encompassing the whole technique using the laser. PATIENT SUMMARY: We reviewed studies to identify the units and terms used for laser performance when treating urinary stones. The review revealed a wide range of differing units, outcomes, and terms. Therefore, we propose a standardized terminology for future studies on laser stone treatment.

Initial experience with the graphical user interface for laser parameters setting of a new thulium fibre laser source device for urinary pathologies treatment.

BACKGROUND AND OBJECTIVE: We aimed to evaluate the concordance between the pre-settings ranges of thulium fibre laser (TFL) (Coloplast TFL Drive, Denmark) with easy-to-use graphical user interface and the laser settings used by a high-volume endo-urologist during surgical procedures. MATERIALS AND METHODS: In October 2022, we prospectively collected data of 67 patients who underwent TFL Drive (Coloplast, Denmark) for the management of urinary stones. Urothelial tumour (upper tract urinary cancer (UTUC) and bladder) 200 and 150 µm laser fibres were used for procedures. Stones characteristics (size and density) tumours and stenosis localizations, laser-on time (LOT), and laser settings were recorded. We also assessed the ablation speed (mm3/s), laser power (W), and Joules/mm3 values for each lithotripsy. RESULTS: A total 67 patients took part in the study. Median age was 52 (15-81) years. 55 (82%), 8 (12%), and 4 (6%) patients presented urinary stones, urothelial tumour, and stenosis, respectively. Median stone volume was 438 (36-6027) mm3 and median density was 988 (376-2000) HU. Median pulse energy was 0.6 (0.3-1.2), 0.8 (0.5-1) and 1 J for urinary stones, urothelial tumour and stenosis respectably. Endoscopically stone-free rate was 89%. Graphical user interface and surgeon accordance with the safety range were observed in 93.2%, 100% and 100% for urinary stones, UTUC and stenosis, respectively. CONCLUSION: During endoscopic procedures for urinary stones treatment, it is frequently needed to change laser parameters. These new TFL and GUI technology parameters remained in the pre-set security range in 94.1% of procedures.

Pulsed thulium:YAG laser-ready to dust all urinary stone composition types? Results from a PEARLS analysis.

PURPOSE: To evaluate whether stone dust can be obtained from all prevailing stone composition types using the novel pulsed thulium:YAG (p-Tm:YAG), including analysis of stone particle size after lithotripsy. METHODS: Human urinary stones of 7 different compositions were subjected to in vitro lithotripsy using a p-Tm:YAG laser with 270 µm silica core fibers (Thulio®, Dornier MedTech GmbH®, Wessling, Germany). A cumulative energy of 1000 J was applied to each stone using one of three laser settings: 0.1 J × 100 Hz, 0.4 J × 25 Hz and 2.0 J × 5 Hz (average power 10 W). After lithotripsy, larger remnant fragments were separated from stone dust using a previously described method depending on the floating ability of dust particles. Fragments and dust samples were then passed through laboratory sieves to evaluate stone particle count according to a semiquantitative analysis relying on a previous definition of stone dust (i.e., stone particles ≤ 250 µm). RESULTS: The p-Tm:YAG laser was able to produce stone dust from lithotripsy up to measured smallest mesh size of 63 µm in all seven stone composition types. Notably, all dust samples from all seven stone types and with all three laser settings had high counts of particles in the size range agreeing with the definition stone dust, i.e., ≤ 250 µm. CONCLUSION: This is the first study in the literature proving the p-Tm:YAG laser capable of dusting all prevailing human urinary stone compositions, with production of dust particles ≤ 250 µm. These findings are pivotal for the broader future implementation of the p-Tm:YAG in clinical routine.

Endoscopic Conservative Treatment of Upper Urinary Tract Urothelial Carcinoma with a Thulium Laser: A Systematic Review.

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

Navigating urolithiasis treatment: assessing the practicality and performance of thulium fiber laser, holmium YAG, and thulium YAG in real-world scenarios.

BACKGROUND: The management of urolithiasis has undergone significant advancements with the introduction of pulsed lasers, particularly the holmium:yttrium-aluminum-garnet (Ho:YAG) laser, which is currently considered the gold standard in endourology. However, the Ho:YAG laser has certain limitations, such as the inability to support small laser fibers (150 µm) and the requirement of a heavy water cooling system, making it challenging to transfer between operating rooms. These limitations have led to the emergence of new laser technologies, including the thulium fiber laser (TFL) and the thulium:yttrium-aluminum-garnet laser (Tm:YAG), as potential alternatives to the Ho:YAG laser. METHODS: In this review, we aimed to evaluate the effectiveness and safety of TFL, Ho:YAG, and Tm:YAG lasers in real-life scenarios by comparing clinical trial data with laboratory findings. A literature review was conducted, and relevant in vitro studies and clinical trials until March 2023 were analyzed. RESULTS: The findings indicate that TFL has demonstrated high ablation efficiency for stones of any composition, size, and location, superior the capabilities of Ho:YAG lasers. TFL has shown superior dusting and fragmentation abilities, lower retropulsion, and increased patient safety. The laser parameters, such as ablation efficiency, speed, operative time, dust quality, retropulsion, visibility, temperature safety, and stone-free rate, were compared between laboratory studies and clinical outcomes. CONCLUSION: Although the number of studies on TFL is limited, the available evidence suggests that TFL represents a significant advancement in laser technology for lithotripsy. However, further research is needed to fully explore the implications and limitations of TFL and Tm:YAG lasers.

Initial clinical experience with the pulsed solid-state thulium YAG laser from Dornier during RIRS: first 25 cases.

INTRODUCTION: Holmium:yttrium-aluminium-garnet (Ho:YAG) and thulium fiber (TFL) lasers are currently the two laser sources recommended for endocorporeal laser lithotripsy (ELL). Recently, the pulsed-thulium:YAG (Tm:YAG) laser was also proposed for ELL, as an answer to both Ho:YAG and TFL limitations. We aimed to evaluate the efficiency, safety, and laser settings of Tm:YAG laser in ELL during retrograde intrarenal surgery (RIRS). METHODS: A prospective study of the first 25 patients with ureteral and renal stones who underwent RIRS using the Thulio (pulsed-Tm:YAG, Dornier©, Germany) was performed in a single center. 272 µm laser fibers were used. Stone size, stone density, laser-on time (LOT) and laser settings were recorded. We also assessed the ablation speed (mm3/s), Joules/mm3 and laser power (W) values for each procedure. Postoperative results, such as stone-free rate (SFR) and zero fragments rate (ZFR) were also recorded. RESULTS: A total of 25 patients were analyzed (Table 1). The median (IQR) age was 55 (44-72) years old. Median (IQR) stone volume was 2849 (916-9153)mm3. Median (IQR) stone density was 1000 (600-1174)HU. Median (IQR) pulse energy, pulse rate and total power were 0.6 (0.6-0,8)J, 15(15-20)Hz and 12(9-16)W, respectively. All procedures used "Captive Fragmenting" pulse modulation (Table 2). The median (IQR) J/mm3 was 14,8 (6-21). The median (IQR) ablation rate was 0,75 (0,46-2)mm3/s. One postoperative complications occurred (streinstrasse). SFR and ZFR were 95% and 55%, respectively. CONCLUSION: The pulsed-Tm:YAG laser is a safe and effective laser source for lithotripsy during RIRS, using low pulse energy and low pulse frequency.