Caveat Emptor: The Heat Is "ON": An In Vivo Evaluation of the Thulium Fiber Laser and Temperature Changes in the Porcine Kidney during Dusting and Fragmentation Modes

Temperature variations with Ho: YAG and thulium fiber lasers, including advanced fragmentation pulse (AFP) technology: an experimental analysis

PURPOSE

Recent developments in high-power systems and the super-pulsed thulium fiber laser (TFL) promise enhanced efficiency but raise concerns about thermal safety. This study examines the intrarenal temperature profiles of Ho: YAG and TFL systems including the advanced fragmentation pulse (AFP) mode under simulated conditions.

METHODS

A custom-designed kidney and ureter model was used to measure intrarenal temperature changes during laser activation. Real-time temperature data were recorded via thermocouples placed in collecting system. Results were analyzed to compare water temperature increases with the safety threshold of 43 °C.

RESULTS

At an irrigation flow rate of 23 mL/min and an initial water temperature of 22 ± 1 °C, WTIs for all laser systems remained below the safety threshold of temperature increase (STTI) during 60 s of laser activation. Ho: YAG consistently demonstrated the lowest WTIs, whereas TFL in AFP mode showed higher WTIs comparable to Ho: YAG but lower compared to TFL standard mode. Across all settings, WTIs were highest in the pelvis due to proximity to the laser fiber, with lower values in the upper and lower poles. The rapid temperature rise observed in the first 10-15 s was followed by a slower, steady increase. These findings confirm that with proper irrigation, even high-power laser lithotripsy systems, including TFL with AFP, operate within thermally safe limits.

CONCLUSION

This study confirms that both Ho: YAG and TFL systems, including AFP mode, remain thermally safe with adequate irrigation (23 mL/min) during 60-second activation sessions.

Initial experience of thulium fiber laser in retrograde intrarenal surgery for ureteral and renal stones in Japan: surgical outcomes and safety assessment compared with holmium: yttrium-aluminum-garnet with MOSES technology

BACKGROUND

Thulium fiber laser (TFL) has been used for the treatment of ureteral and renal stones in Japan since October 2023. However, there are no reports on the initial results of TFL in Japan. This study aimed to assess the initial results of TFL in retrograde intrarenal surgery (RIRS) and to compare them with those of holmium: yttrium-aluminum-garnet (Ho: YAG) laser with MOSES technology.

METHODS

This retrospective single-center study compared perioperative results, complications, and the "stone-free" rate (defined as ≤ 2 mm fragments on computed tomography 1 month after RIRS) between the TFL (60 W) (group A, n = 48) and Ho: YAG laser with MOSES technology (120 W) (group B, n = 48) laser. The inclusion criteria were renal or ureteral stones ≤ 20 mm in diameter and those scheduled for single-stage RIRS.

RESULTS

The two groups had similar baseline patient characteristics. No significant differences were found in operative time (45 vs. 54 min, P = 0.10), laser time (15 vs. 10 min, P = 0.12), stone-free rate (97.9% vs. 95.8%, P = 1.00), ureteral injury (2.1% vs. 8.3%, P = 0.36), or postoperative fever (0% vs. 4.2%, P = 0.49) between groups A and B. However, significant differences were found in basketing time (7 vs. 21 min, P < 0.01) between groups A and B.

CONCLUSIONS

Our study showed that RIRS with TFL had similar results and no difference in complications compared to RIRS with Ho: YAG laser with MOSES technology. The TFL had a significantly shorter basketing time than the Ho: YAG laser with MOSES technology. Furthermore, future research is needed to determine suitable laser settings for the TFL.

Prospective evaluation of efficacy, safety, cumulative laser energy, and stone-free rates in the post-market SOLTIVE™ SuperPulsed laser system registry: insights from team of worldwide endourological researchers' (T.O.W.E.R.) research consortium

The Thulium fiber laser (TFL) is a relatively new tool for endoscopic laser lithotripsy. The Endourological Society's T.O.W.E.R. registry sought to evaluate the stone-free rate (SFR) at 3 months following URS. A subset of the study sought to determine the association between cumulative TFL energy and SFRs. 423 patients with planned ureteroscopic lithotripsy using TFL (SOLTIVE™, Gyrus ACMI, Inc. d/b/a Olympus Surgical Technologies America) were prospectively enrolled between December 2020 and May 2023 at nine international sites. Baseline clinical characteristics and SFR data for kidney and ureteral stones were separately analyzed according to quartile cumulative TFL energy ranges. Median patient age was 58.0 (IQR: 44-67) years and maximal stone diameters were 9.9 (IQR: 7-12.9) mm and 7.4 (IQR 6.1-9.4) mm for kidney and ureteral stones, respectively. Overall SFR (no fragments) for renal and ureteral stones were 73.0% and 85.7% at 3-months. Cumulative energy levels were divided into quartiles and lower SFRs were observed with the highest quartile for kidney stones (p = 0.001), but not in ureteral stones. This correlated with kidney stone size as larger stones required more energy. The rate of adverse events related to the procedure was 1.9% (8/423). Higher stone burdens had lower stone free rates and required more cumulative laser energy. The TFL is effective in endoscopic lithotripsy. This post-marketing survey demonstrates that TFL is a safe and effective tool for endoscopic laser lithotripsy.

Warm irrigation fluid effect on Thulium fiber laser (TFL) ablation of uroliths

Prior laser studies have demonstrated that as the temperature of a medium increases, the amount of energy delivered to the target increases. We sought to investigate the role of irrigation fluid temperature on Thulium fiber laser (TFL) urolith ablation. 360 calculi were divided in vitro according to chemical composition: calcium oxalate monohydrate (COM), cystine (CYS), struvite (STR), calcium phosphate (CAP), uric acid (UA), and calcium oxalate dihydrate (COD). A 200 μm TFL was placed directly on each stone, while immersed in 0.9% NaCl at four different temperatures (25 C, 37 C, 44 C, 60 C) and a single laser pulse administered at distinct energy settings (0.1 J, 0.5 J, 1.5 J). Optical coherence tomography assessed the resulting ablation cone volume. Mean stone volume and porosity were evaluated through ANOVA and Tukey post-hoc analysis. A multivariate generalized model for each composition accounted for the impact of fluid temperature and laser energy on stone ablation. Warmer fluid temperatures yielded greater ablation cone volumes for most energy settings, excluding UA stones. When accounting for chemical composition, higher tensile strength stones (COM, CYS) benefited most from warmer fluid in comparison to frangible stones (CAP, STR). The effects of increasing fluid temperature are modest relative to laser pulse energy as a large temperature increase (i.e. 7ºC) is equivalent to a minor energy increase (i.e. 0.1 J). For non-UA stones, TFL ablation efficiency increases with warmer irrigation fluid. The effect, albeit modest compared to laser pulse energy, was most notable for COM and CYS stones.

Novel pressure- and temperature-controlled flexible ureteroscope system with a suction ureteral access sheath: a multicenter retrospective feasibility study

PURPOSE

The purpose of this study was to assess the feasibility of a pressure-controlled and temperature-controlled flexible ureteroscope system (PT Scope™) during flexible ureteroscopy.

MATERIALS AND METHODS

We developed the PT Scope™, a novel ureteroscope system with capabilities for monitoring and controlling intrarenal pressure and temperature to maintain them within set parameters. Data were retrospectively collected from 48 consecutive patients diagnosed with upper urinary tract stones who underwent flexible ureteroscopic lithotripsy using the PT Scope™ across five centers in China. Analyses focused on 24-h postoperative stone-free rates, intrarenal pressure and temperature measurements, and other procedural data.

RESULTS

Among the 48 patients treated with the PT Scope™ system, a significant stone-free rate of 89.6% was achieved within 24 h postoperation, without any instances of intraoperative complications such as perforation or mucosal hemorrhage. Only two patients reported mild postoperative pain and were managed with NSAIDs, and there were no cases of postoperative fever or sepsis. The average maximum intrarenal pressure and temperature were recorded at 30.2 ± 4.20 mmHg and 36.6 ± 4.27 °C, respectively. Notably, during lithotripsy, both the pressure and temperature were maintained below 30 mmHg and 43 °C for 99% of the procedure duration, respectively.

CONCLUSION

This preliminary investigation indicates that the PT Scope™ is a safe and effective tool for the treatment of upper urinary tract stones, offering the benefit of regulating intrarenal pressure and temperature within predetermined limits. These findings support the feasibility of the system for clinical application.

Assessing renal tissue temperature changes and perfusion effects during laser activation in an in vivo porcine model

INTRODUCTION

High fluid temperatures have been seen in both in vitro and in vivo studies with laser lithotripsy, yet the thermal distribution within the renal parenchyma has not been well characterized. Additionally, the heat-sink effect of vascular perfusion remains uncertain. Our objectives were twofold: first, to measure renal tissue temperatures in response to laser activation in a calyx, and second, to assess the effect of vascular perfusion on renal tissue temperatures.

METHODS

Ureteroscopy was performed in three porcine subjects with a prototype ureteroscope containing a temperature sensor at its tip. A needle with four thermocouples was introduced percutaneously into a kidney with ultrasound guidance to allow temperature measurement in the renal medulla and cortex. Three trials of laser activation (40W) for 60 s were conducted with an irrigation rate of 8 ml/min at room temperature in each subject. After euthanasia, three trials were repeated without vascular perfusion in each subject.

RESULTS

Substantial temperature elevation was observed in the renal medulla with thermal dose in two of nine trials exceeding threshold for tissue injury. The temperature decay time (t½) of the non-perfused trials was longer than in the perfused trials. The ratio of t½ between them was greater in the cortex than the medulla.

CONCLUSION

High-power laser settings (40W) can induce potentially injurious temperatures in the in vivo porcine kidney, particularly in the medullary region adjacent to the collecting system. Additionally, the influence of vascular perfusion in mitigating thermal risk in this susceptible area appears to be limited.

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.

Learning from the past and present to change the future: Endoscopic management of upper urinary tract urothelial carcinoma

Current guidelines recommend endoscopic management (EM) for patients with low-risk upper urinary tract urothelial carcinoma, as well as those with an imperative indication. However, regardless of the tumor risk, radical nephroureterectomy is still mainly performed worldwide despite the benefits of EM, such as renal function maintenance, no hemodialysis requirement, and treatment cost reduction. This might be explained by the association of EM with a high risk of local recurrence and progression. Furthermore, the need for rigorous patient selection and close surveillance following EM may be relevant. Nevertheless, recent developments in diagnostic modalities, pathological evaluation, surgical devices and techniques, and intracavitary regimens have been reported, which may contribute to improved risk stratification and treatments with superior oncological outcomes. In this review, considering recent advances in endourology and oncology, we propose novel treatment strategies for optimal EM.

Retrograde intra renal surgery and safety: pressure and temperature. A systematic review

PURPOSE OF REVIEW

Retrograde intra renal surgery (RIRS) with laser lithotripsy represents the gold-standard to treat renal stones up to 20 mm. Controlling intraoperative parameters such as intrarenal pressure (IRP) and temperature (IRT) is mandatory to avoid complications. This article reviews advances in IRP and IRT over the last 2 years.

RECENT FINDINGS

We conducted a PubMed/Embase search and reviewed publications that include temperature and pressure during RIRS. Thirty-four articles have been published which met the inclusion criteria. Regarding IRP, a consensus has emerged to control IRP during RIRS, in order to avoid (barotraumatic and septic) complications. Several monitoring devices are under evaluation but none of them are clinically approved for RIRS. Ureteral access sheath, low irrigation pressure and occupied working channel help to maintain a low IRP. Robotic systems and suction devices would improve IRP intraoperative management and monitoring. IRT determinants are the irrigation flow and laser settings. Low power settings(<20 W) with minimal irrigation flow (5-10 ml/min) are sufficient to maintain low IRT and allows continuous laser activation.

SUMMARY

Recent evidence suggests that IRP and IRT are closely related. IRP depends on inflow and outflow rates. Continuous monitoring would help to avoid surgical and infectious complications. IRT depends on the laser settings and the irrigation flow.

Lasers for stone lithotripsy: advantages/disadvantages of each laser source

PURPOSE

The purpose of this article was to make a narrative review of the literature in search of all articles regarding thulium:yttrium-aluminium-garnet (YAG), thulium laser fiber (TFL) and holmium:YAG (Ho:YAG) for lithotripsy from 2020 to 2023. A selection of articles of special interest and best evidence was made in order to give a better perspective on their advantages and disadvantages.

RECENT FINDINGS

New Ho:YAG technologies of as high power, high frequency and pulsed modulations have shown promising results for lithotripsy by reducing retropulsion with good ablation efficiency. High peak power makes it particularly good for percutaneous nephrolithotomy. High intrarenal temperatures and correct setting are still concerning points.TFL has arrived to be one of the main players in flexible ureteroscopy. Being highly efficient and quick, and by producing micro-dusting the laser is quickly heading to become a gold standard. The new pulsed Thulium YAG is the newest laser. For now, only in-vitro studies show promising results with efficient lithotripsy. As the peak power lies between Ho:YAG and TFL it may be able to adequately perform when needing and low power lithotripsy.

SUMMARY

Several new technologies have been developed in the last years for stone lithotripsy. All being efficient and safe if well used. Different advantages and disadvantages of each laser must be taken into consideration to give each laser the proper indication.

Different ureteral access sheaths sizes for retrograde intrarenal surgery

PURPOSE

There is a trend toward miniaturization in endourological stone therapy. Good visibility, intrarenal pressures and temperature control should be ensured by ureteral sheaths. In the context of the present study, 10/12 Charr. sheaths and 12/14 Charr. sheaths for flexible ureterorenoscopy were investigated regarding stone-free rate, complication rate and efficacy for laser lithotripsy.

METHODS

From January 2020 to January 2022, 100 patients each with kidney stone up to 1.5 cm in diameter were included in the study. Use of a 12/14 Charr. vs. 10/12 Charr. ureteral sheath for flexible ureterorenoscopy was compared. Perioperative data, stone size, volume and density, laser energy, laser duration, stone-free rates and complications based on Clavien-Dindo classification were retrospectively analyzed.

RESULTS

For both groups of ureteral access sheaths, there were no differences in median surgery duration (10/12 Charr: 29 min (7-105 min) vs. 12/14 Charr: 34 min (9-95 min); p = 0.33), overall complication rate (p = 0.61) and hospitalization (p = 0.155). There were no differences in stone-free rates (97.9% vs. 92.7%, p = 0.37). Laser lithotripsy duration usingholmium laser was 1.9 min (0.1-10.8 min) vs. 3.8 min (0.2-20.7 min) (p < 0.01) and applied laser energy was 3.1 J (0.15 J-10.29 J) vs. 6.8 J (1.07 J-26.77 J) (p < 0.01) for 12/14 Charr. sheaths and 10/12 Charr. sheaths, respectively.

CONCLUSION

In terms of stone-free rates, there are no differences between the 10/12 and 12/14 Charr. ureteral access sheaths. The laser duration and energy was increased with 10/12 Charr. sheaths without showing increased risk for clinical complications like trauma or inflammation.

Comparison of Superpulse Thulium Fiber Laser vs Holmium Laser for Ablation of Renal Calculi in an In Vivo Porcine Model

Introduction and Objectives: We sought to compare the effectiveness and efficiency of the superpulse thulium fiber laser (sTFL to the holmium: yttrium-aluminum-garnet [Ho:YAG] laser for ureteroscopic "dusting" of implanted renal stones in an in vivo porcine model. Methods: Twenty-four porcine kidneys (12 juvenile female Yorkshire pigs) were randomized to Ho:YAG or sTFL treatment groups. Canine calcium oxalate stones were scanned with computed tomography to calculate stone volume and stone density; the stones were randomized and implanted into each renal pelvis via an open pyelotomy. In all trials, a 14F, 35 cm ureteral access sheath was placed. With a 9.9F dual lumen flexible ureteroscope, laser lithotripsy was performed using dusting settings: Ho:YAG 200 μm laser fiber at 16 W (0.4 J, 40 Hz) or sTFL 200 μm laser fiber at 16 W (0.2 J, 80 Hz). Lithotripsy continued until no fragments over 1 mm were observed. No stone basketing was performed. Throughout the procedures, intrarenal and renal pelvis temperatures were measured using two percutaneously positioned K-type thermocouples, one in the upper pole calyx and one in the renal pelvis. After the lithotripsy, the ureteropelvic junction was occluded, the kidneys were bivalved, and all residual fragments were collected, dried, weighed, and then measured with an optical laser particle sizer. Results: Implanted stones were similar in volume and density in both groups. Intraoperative collecting system temperatures were similar for both groups (all <44°C). Compared to Ho:YAG, sTFL ablated stones faster (9 vs 27 minutes, p < 0.001) with less energy expenditure (8 vs 26 kJ, p < 0.001), and a greater stone clearance rate (73% vs 45%, p = 0.001). After sTFL lithotripsy, 77% of the remaining fragments were ≤1 mm vs 17% of fragments ≤1 mm after Ho:YAG treatment (p < 0.001). Conclusions: In an in vivo porcine kidney, using dusting settings, sTFL lithotripsy resulted in shorter ablation times, higher stone clearance rates, and markedly smaller stone fragments than Ho:YAG lithotripsy.

Thulium fiber laser in endourology: current clinical evidence

PURPOSE OF REVIEW

To review and summarize preclinical and clinical data on thulium fiber laser's (TFL) effectiveness (ablation rate, stone-free rate etc.) and safety in terms of laser injuries and thermal damage. This enables us to assess how the in-vitro evidence translates into the clinical real-life scenario.

RECENT FINDINGS

In this analysis, a total of 21 preclinical trials have been included. Most of the trials use conventional Holmium:YAG laser as a comparator, with only a few assessing lasers with pulse modulation. Most of the trials focus on the superior ablation rate and superior dusting features of TFL, as well as comparison of retropulsion (both in conventional Ho:YAG and in a pulse modulation), with a few studies assessing safety aspects. A total of 13 trials assessed TFL, clinically, in percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS). The clinical data obtained suggest that lithotripsy by TFL is safe, facilitates effective stone fragmentation, and results in a reduction of retropulsion. Unfortunately, most of the clinical trials lack a direct comparator, and so no clear-cut comparisons are possible.

SUMMARY

During in-vitro studies, TFL demonstrated to be a new energy source with a great potential for improved ablation, lower retropulsion and improved dusting. These claims are supported in contemporary clinical studies, reporting superior ablation and negligible retropulsion in both PCNL and RIRS. However, it should be noted that the data regarding clinical results compared with conventional Ho:YAG is still limited.

Thulium fiber laser lithotripsy: Is it living up to the Hype?

Objective

The holmium:yttrium-aluminium-garnet laser (Ho:YAG) has been the gold standard for laser lithotripsy over the last three decades. After demonstrating good in vitro efficacy, the thulium fiber laser (TFL) has been recently released in the market and the initial clinical results are encouraging. This article aims to review the main technology differences between the Ho:YAG laser and the TFL, discuss the initial clinical results with the TFL as well as the optimal settings for TFL lithotripsy.

Methods

We reviewed the literature focusing on the technological aspects of the Ho:YAG laser and TFL as well as the results of in vitro and in vivo studies comparing both technologies.

Results

In vitro studies show a technical superiority of TFL compared to the Ho:YAG laser and encouraging results have been demonstrated in clinical practice. However, as TFL is a new technology, limited studies are currently available, and the optimal settings for lithotripsy are not yet established.

Conclusion

TFL has the potential to be an alternative to the Ho:YAG laser, but more reports are still needed to determine the optimal laser for lithotripsy of urinary tract stones when considering all parameters including effectiveness, safety, and costs.

Glossary of pre-settings given by laser companies: no consensus!

INTRODUCTION

Since the construction of the first laser, many companies around the world have contributed to the development of new lasers technologies. To be user-friendly, some companies have developed a pre-setting mode in their laser devices. We aimed to review and compare all laser companies' pre-settings (PS) already established in the market.

MATERIALS AND METHODS

An online search of holmium:YAG (Ho:YAG) and thulium fiber laser (TFL) devices was carried out. Manual and PS mode, pulse width and pulse modulation technology data were collected. The PS parameters were collected directly from the brochure devices or by asking the companies consulting agents.

RESULTS

Thirty-nine laser devices were analyzed (33 Ho:YAG and 6 TFL). The power range varies from 15 to 152 W and 35 W to 60 W for Ho:YAG and TFL, respectively. PS are present in 66% of Ho:YAG lasers and the 33% of TFL. Long-pulse modes can be modified in 12 Ho:YAG and 1 TFL lasers. The median (IQR) PS for dusting stones with Ho:YAG laser is 0.4 J (0.2-1), 21.5 Hz (5-120), and 10 W (1.5-28) for energy, frequency and power, respectively; for Ho:YAG fragmentation is 0.8 J (0.3-5), 10 (3-15) Hz and 5 (1.5-50) W for energy, frequency, and power, respectively; and for popcorn is 0.8 J (0.4-1.2), 10 Hz (6-15) and 5 W (4-18) for energy, frequency, and power, respectively. Dusting and fragmentation mode of Rocamed MH01 and EMS LaserClast 35 are programmed according to the stone type. Most of these settings do not depend on the size of the fiber being used nor the location and type of stone. For TFL, the pre-sets are divided in bladder stone, dusting, fine dusting, fragmentation, and ureteral stone.

CONCLUSION

There is a huge variability regarding pre-sets offered by companies because there is no consensus. Pre-sets should provide a range to work efficacy and safety.

Ureteral Access Sheaths and Its Use in the Future: A Comprehensive Update Based on a Literature Review

Ureteral access sheaths (UASs) are part of urologist’s armamentarium when performing retrograde intrarenal surgery (RIRS). Recently, the world of RIRS has changed dramatically with the development of three game-changers: thulium fiber laser (TFL), smaller size single use digital flexible ureterosopes and intraoperative intrarenal pressure (IRP) measurement devices. We aimed to clarify the impact of UASs on IRP, complications and SFRs and put its indications in perspective of these three major technological improvements. A systematic review of the literature using the Medline, Scopus and Web of Science databases was performed by two authors and relevant studies were selected according to PRISMA guidelines. Recent studies showed that using a UAS lowers IRP and intrarenal temperature by increasing irrigation outflow during RIRS. Data on the impact of a UAS on SFRs, postoperative pain, risk of infectious complications, risk of ureteral strictures and risk of bladder recurrence of urothelial carcinoma after diagnostic RIRS were inconclusive. Prestenting for at least one week resulted in ureteral enlargement, while the influence of pre-operative administration of alpha-blockers was unclear. Since TFL, smaller single use digital ureteroscopes and devices with integrated pressure-measuring and aspiration technology seemed to increase SFRs and decrease pressure and temperature related complications, indications on the use of a UAS may decrease in the near future.

Initial clinical experience with the thulium fiber laser from Quanta System: First 50 reported cases

OBJECTIVE

To evaluate the new thulium fiber laser (TFL) from Quanta System (Fiber Dust™) in terms of efficiency, safety, and laser settings in laser lithotripsy during retrograde intrarenal surgery (RIRS).

METHODS

A prospective study of the first 50 patients with ureteral and renal stones who underwent RIRS using the new Fiber Dust (TFL from Quanta System, Italy) was performed in a single center. 200 µm and 150 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.

RESULTS

A total of 50 patients were analyzed. The median (IQR) age was 54.5 (43-65) years old. Median (IQR) stone volume was 347 (147-1800) mm³ and 1125 (294-4000) mm³ for ureteral and renal stones, respectively. Median (IQR) stone density was 900 (400-1500) HU for ureteral stones and 950 (725-1125) HU for renal stones. Median (IQR) pulse energy was 0.6 (0.5-1) J and 0.6 (0.5-0.9) J for ureteral and renal stones, respectively. Median (IQR) frequency for ureteral stones was 10 (10-20) Hz and for renal stones, 15 (10-20) Hz. All procedures used short pulse. There were no statistically significant differences in pulse energy, frequency, laser power or LOT in both groups. The median (IQR) J/mm³ was 8.7 (4.8-65.2) for ureteral stones vs 14.3 (7.8-24.7) for renal stones. The median (IQR) ablation rate was 0.3 (0.2-1.3) mm³/s for ureteral stones vs 0.7 (0.4-1.2) mm³/s for renal stones. Neither of those results reached the significance threshold. Overall complication rate was low in both groups, and none was related to TFL.

CONCLUSION

According to our results, the new TFL laser is safe and effective for lithotripsy during RIRS, using low pulse energy and low pulse frequency.

A Practical Guide for Intra-Renal Temperature and Pressure Management during Rirs: What Is the Evidence Telling Us

INTRODUCTION

One of the main limitations of Ho:YAG lithotripsy is represented by its advancement speed. The need for faster lithotripsy has led to the introduction of high-power laser equipment. This general trend in increasing Ho:YAG lithotripsy power has certain points that deserve to be considered and analyzed. The objective is to carry out a narrative review on intrarenal temperature and pressure during ureteroscopy.

METHODS

A literature search using PUBMED database from inception to December 2021 was performed. The analysis involved a narrative synthesis.

RESULTS

Using more power in the laser correlates with an increase in temperature that can be harmful to the kidney. This potential risk can be overcome by increasing either the irrigation inflow or outflow. Increasing irrigant flow can lead to high intrarenal temperature (IRP). The factors that allow the reduction of intrarenal pressure are a low irrigation flow, the use of a ureteral access sheath of adequate diameter according to the equipment used, and the occupation of the working channel by the laser or basket.

CONCLUSION

To maintain a safe temperature profile, it has been proposed to use chilled irrigation fluid, intermittent laser activation or to increase irrigation flow. This last recommendation can lead to increased IRP, which can be overcome by using a UAS. Another option is to use low power laser configurations in order to avoid temperature increases and not require high irrigation flows.

Thulium fiber laser pre-settings during ureterorenoscopy: Twitter's experts' recommendations

INTRODUCTION

Thulium fiber laser (TFL) is a novel laser in the field of urology. There is no consensus for optimal parameters. As most urologists use social media, being Twitter the platform with the most dissemination in healthcare, we aim to review the preferred TFL settings chosen by the experts and, to evaluate their pros and cons.

MATERIALS AND METHODS

A Twitter review was performed from November 2019 (firsts TFL experiences in urology) until October 2021 using the hashtags: "thuliumfiber", "ThuliumFiberLaser", "TFL" "soltive", "fiberdust", "OlympusUrology", "quanta_system", "IPG_Photonics", "rocamed". Only board-certified urologists were considered. The "tweets" selected include information about TFL preferred settings for stone lithotripsy and tissue ablation. Additionally, we also seek information regarding laser technique, fiber size, laser time, stone type and equipment.

RESULTS

A total of 42 opinions were identified. The 23 endourologists have a median of 2.298 followers (range 202-10.000). Most comments were about TFL settings for kidney stone dusting (61%). There was a significant difference (p < 0.05) for kidney stone dusting settings (dusting, frequency, and power) between endourologists. Only 24% reported their fiber size, 4 reported the stone composition and 2 endourologists mentioned their type of ureteroscope. There was no discussion about technique used (burst or continuous) nor equipment. Surgery time was reported 3 times.

CONCLUSION

There is no consensus in TFL pre-settings. When a pre-setting is proposed, it should also recommend technique to be used. Settings are personal and related to multiple factors, such as training, technique, equipment and fiber size.

Routine use of ureteral access sheaths for ureteroscopy, yay or nay?

n/a.

The Life and Death of Percutaneous Stone Removal: "Looking Back-Looking Forward"

Although percutaneous nephrolithotomy (PCNL) is less morbid than open surgery, it still carries risks of significant complications as well as injury to the renal parenchyma. Flexible ureteroscopic stone removal, although causes no appreciable damage to the renal parenchyma, has limitations, most notably, a lower stone-free rate than PCNL. Advances in our knowledge regarding ureteral physiology combined with technical developments applied to ureteral access sheath deployment and size may well propel retrograde intrarenal surgery to the forefront of kidney stone removal, regardless of stone size or location.