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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 mm 3 (Ho:YAG), 500-750 mm 3 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., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective: Current interventional guidelines refer to the cumulative stone diameter to choose the appropriate surgical modality (ureteroscopy [URS], extracorporeal shockwave lithotripsy [ESWL] and percutaneous nephrolithotomy [PCNL]). The stone volume (SV) has been introduced recently, to better estimate the stone burden. This review aimed to summarize the available methods to evaluate the SV and its use in urolithiasis treatment., Material and Methods: A comprehensive review of the literature was performed in December 2022 by searching Embase, Cochrane and Pubmed databases. Articles were considered eligible if they described SV measurement or the stone free rate after different treatment modalities (SWL, URS, PCNL) or spontaneous passage, based on SV measurement. Two reviewers independently assessed the eligibility and the quality of the articles and performed the data extraction., Results: In total, 28 studies were included. All studies used different measurement techniques for stone volume. The automated volume measurement appeared to be more precise than the calculated volume. In vitro studies showed that the automated volume measurement was closer to actual stone volume, with a lower inter-observer variability. Regarding URS, stone volume was found to be more predictive of stone free rates as compared to maximum stone diameter or cumulative diameter for stones >20 mm. This was not the case for PCNL and SWL., Conclusions: Stone volume estimation is feasible, manually or automatically and is likely a better representation of the actual stone burden. While for larger stones treated by retrograde intrarenal surgery, stone volume appears to be a better predictor of SFR, the superiority of stone volume throughout all stone burdens and for all stone treatments, remains to be proven. Automated volume acquisition is more precise and reproducible than calculated volume., (Copyright © 2023 AEU. Published by Elsevier España, S.L.U. All rights reserved.)

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., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: The novel pulsed thulium:yttrium-aluminum-garnet (p-Tm:YAG) laser was recently introduced. Current studies present promising p-Tm:YAG ablation efficiency, although all are based on non-human stone models or with unknown stone composition. The present study aimed to evaluate p-Tm:YAG ablation efficiency for stone dust from human urinary stones of known compositions., Methods: Calcium oxalate monohydrate (COM) and uric acid (UA) stones were subjected to lithotripsy in vitro using a p-Tm:YAG laser generator (Thulio®, Dornier MedTech GmbH, Germany). 200 J was applied at 0.1 J × 100 Hz, 0.4 J × 25 Hz or 2.0 J × 5 Hz (average 10W). Ablated stone dust mass was calculated from weight difference between pre-lithotripsy stone and post-lithotripsy fragments > 250 µm. Estimated ablated volume was calculated using prior known stone densities (COM: 2.04 mg/mm 3 , UA: 1.55 mg/mm 3 )., Results: Mean ablation mass efficiency was 0.04, 0.06, 0.07 mg/J (COM) and 0.04, 0.05, 0.06 mg/J (UA) for each laser setting, respectively. This translated to 0.021, 0.029, 0.034 mm 3 /J (COM) and 0.026, 0.030, 0.039 mm 3 /J (UA). Mean energy consumption was 26, 18, 17 J/mg (COM) and 32, 23, 17 J/mg (UA). This translated to 53, 37, 34 J/mm 3 (COM) and 50, 36, 26 J/mm 3 (UA). There were no statistically significant differences for laser settings or stone types (all p > 0.05)., Conclusion: To our knowledge, this is the first study showing ablation efficiency of the p-Tm:YAG laser for stone dust from human urinary stones of known compositions. The p-Tm:YAG seems to ablate COM and UA equally well, with no statistically significant differences between differing laser settings., (© 2023. The Author(s).)

Objectives: To assess the effect of various factors on laser fiber tip degradation with the thulium fiber laser (Tm-fiber): fiber stripping, adjustable laser settings (energy, frequency, peak power), and stone density. Methods: Two hundred seventy-three micrometer fibers were used with a 50W Tm-fiber. First, we assessed the evolution of power transmission with stripped and unstripped fibers submerged in saline. The laser was continuously activated for 5 minutes. The influence of each laser parameter (energy, frequency, and peak power) on fiber degradation was assessed by loss of power transmission and reduction of tip length. Second, we assessed the evolution of power transmission after 150 seconds of lithotripsy in a quasicontact mode against soft and hard BegoStones. The influence of lithotripsy with different laser settings on fiber degradation was assessed by loss of power transmission. Results: Power transmission was close to 100% with stripped fibers, while a power gain appeared for unstripped fibers after 5 minutes of laser emission. Thus, only stripped laser fibers were used during the second series of experiments. Regardless of laser settings, there was a constant loss of measured power transmission after lithotripsy with a significant difference between soft and hard stones, p  < 0.0001. Power transmission was 67% and 78% against hard and soft stones, respectively. While there was no influence of peak power on power output against hard stones, there was a significant one against soft stones. Conclusions: The main determinant of loss of power transmission during lithotripsy in contact mode with Tm-fiber is the stone density. Higher loss of power transmission occurs against hard stones than soft stones. All peak powers may be used against hard stones without a difference, while high peak power appears as an additional factor of power loss against soft stones, but this decrease will not the reach the one obtained with hard stones.

Les avancées technologiques en endo-urologie font désormais de l'urétéroscopie souple (URSS) une technique de choix pour traiter les calculs urinaires mais aussi un casse-tête lorsqu'il s'agit de choisir son équipement. La mise en place d'un guide de sécurité au sein des cavités rénales (nitinol, 0,035″, « stiff ») par cystoscopie rigide est non obligatoire mais constitue un critère de sécurité. Il en est de même concernant les gaines d'accès urétéral, celles avec aspiration étant en cours d'évaluation. Si leur utilisation réduit la pression et la température au sein des cavités rénales facilitant la vision, leur insertion peut occasionner des lésions urétérales. Les systèmes d'irrigation utilisant la gravité avec pompe manuelle sont à privilégier pour minimiser le risque de barotraumatisme. Le choix de l'urétéroscope est complexe : diamètre, capacité de déflexion, position du canal opérateur et qualité de vision sont à considérer. Aussi, il est difficilement envisageable de n'utiliser qu'un modèle endoscope pour l'intégralité des URSS. Les lasers Holmium:Yttrium-Aluminium-Grenat (Ho:YAG) et Thulium Fibré (TFL) sont aujourd'hui recommandés pour le traitement des calculs urinaires en URSS, avec un avantage potentiel du TFL pour la pulvérisation fine. Les paniers sont nombreux et divers, leur taille et forme devant également être considérées avant acquisition. En fin d'intervention, un drainage urétéral n'est pas systématique, mais les sondes JJ en silicone ont montré des risques d'incrustation et de gêne fonctionnelle plus faibles que les sondes faites de polyuréthane. Flexible ureteroscopy is now widely used as the preferred option to surgically treat a urinary stone, due to several technological advancements. Thus, choosing the adequate equipment is challenging, but respects safety concepts. Indeed, placing the safety wire (nitinol, 0,035″, "stiff") under rigid cystoscopy is not mandatory but improve safety. Regarding ureteral access sheath (UAS), considerations are similar: UAS facilitates vision, pressure and temperature control but can also be responsible of ureteral injuries at insertion. Suction devices are now under evaluation and could not be discussed. To limit the barotrauma risk, irrigation devices with manual pumps should be used (40 cmH 2 0). Choosing a flexible ureteroscope (fURS) is challenging; a special attention has to be given to size, deflexion, working channel position and vision. Thus, using a single fURS is hardly imaginable. Both Holmium:Yttrium-Aluminium-Garnet (Ho:YAG) and Thulium Fiber (TFL) lasers are recommended to treat urinary stones during fURS, with a potential advantage of TFL on thin pulverization. A wide variety of baskets exists and size and shape have to be considered before acquisition. Finally, if ureteral stenting is not mandatory in uncomplicated cases, silicone stents present a lower risk of encrustation and stent-related symptoms compared to polyurethane ones. [ABSTRACT FROM AUTHOR]

Décrire la technologie du laser Thulium:Yttrium-Aluminium-Garnet pulsé (p-Tm:YAG) et ses résultats actuels pour lithotritie laser endocorporelle. Une revue de la littérature, interrogeant les bases Pubmed, Scopus, et Cochrane a été conduite en janvier 2024 utilisant les mots clés « laser », « pulsed Thulium:YAG », « stones » et « lithotripsy ». De par les faibles niveaux de preuve et nombre de publications, une revue narrative de la littérature a été réalisée. Le laser p-Tm:YAG est un laser à cavité avec un cristal YAG dopé aux ions thulium, pompé par des diodes laser. Avec une longueur d'onde du faisceau laser de 2013 nm, il présente un coefficient d'absorption dans l'eau intermédiaire entre le laser Ho:YAG et TFL. Le diamètre minimal utilisable des fibres laser est de 200 μm. Différentes modulations impulsionnelles sont proposées visant à minimiser la rétropulsion des calculs avec notamment une puissance crête (Peak Power) réglable (≥ 800 W). De multiples études comparatives in vitro suggèrent que la capacité du p-Tm:YAG à fragmenter les calculs serait similaire à celle de l'Ho:YAG ; au contraire, sa capacité à pulvériser (dusting) tous types de calculs serait similaire à celle du TFL, avec une faible rétropulsion. Une seule étude in vivo a confirmé la faisabilité de la lithotritie du p-Tm:YAG au cours d'une urétéroscopie souple avec des taux de sans fragment résiduel (< 3 mm) et zéro fragment résiduel de 95 % et 55 %, respectivement. Aucune étude comparative n'est disponible à ce jour. Le nouveau laser p-Tm:YAG pulsé pourrait représenter un compromis sûr et efficace entre le laser Ho:YAG et le TFL pour la lithotritie laser endocoporelle mais des études comparatives, notamment avec le TFL sont nécessaires pour définir sa place dans l'arsenal thérapeutique. To describe the pulsed-Thulium:Yttrium-Aluminum Garnet (p-Tm:YAG) laser technology and its current evidence for endoscopic laser lithotripsy. A literature review, querying PubMed, Scopus, and Cochrane databases, was conducted in January 2023 using keywords "laser", "pulsed Thulium:YAG", "stones" and "lithotripsy". Due to the limited level of evidence and the number of publications, a narrative literature review was undertaken. The p-Tm:YAG laser is a cavity laser with a thulium-doped YAG crystal, pumped by laser diodes. With a laser beam wavelength of 2013 nm, p-Tm:YAG presents an intermediate absorption coefficient in water between Ho:YAG and TFL lasers. The minimal usable diameter of laser fibers for this technology is 200 μm. Various pulse modulations are proposed to minimize stone retropulsion, including adjustable peak power (≥ 800 W). Multiple in vitro comparative studies suggest that p-Tm:YAG's ability to fragment stones is similar to that of Ho:YAG, while its ability to dust various types of stones is similar to TFL, with low retropulsion. A single in vivo study confirmed the feasibility of p-Tm:YAG lithotripsy during flexible ureteroscopy, with stone-free (< 3 mm) and zero-fragment rates of 95% and 55%, respectively. No comparative studies are available to date. The new pulsed p-Tm:YAG laser could represent a safe and effective compromise between Ho:YAG and TFL for endoscopic laser lithotripsy, but comparative studies, especially with TFL, are necessary to define its role in the therapeutic arsenal. [ABSTRACT FROM AUTHOR]