Ureteroscopic Performance of High Power Super Pulse Thulium Fiber Laser for the Treatment of Urolithiasis: Results of the First Case Series in North America

[Thulium or holmium laser or both: where will the journey take us?]

The Holmium:YAG laser has been the gold standard for laser lithotripsy over the past three decades and, since the late 1990s, also for prostate enucleation. Pulsed thulium fibre lasers (TFL) demonstrated their efficacy in in-vitro experiments and were introduced to the market a few years ago. Initial clinical results for TFL in lithotripsy and enucleation are very promising. In addition to TFL, a pulsed Thulium:YAG solid-state laser has been introduced, but clinical data for this laser are currently limited. This article aims to review the key technological differences between Ho:YAG lasers and pulsed thulium lasers and compare/discuss the initial clinical results for stone lithotripsy and laser enucleation.In-vitro studies have demonstrated the technical superiority of TFL compared with Ho:YAG lasers. However, as TFL is still a new technology, only limited studies are available to date, and optimal settings for lithotripsy have not been established. For enucleation, the differences of TFL compared with a high-power Ho:YAG laser seem to be clinically irrelevant. Initial studies on pulsed Tm:YAG lasers show good results, but there continues to be a lack of comparative studies.Based on the current literature, pulsed thulium lasers have the potential of being an alternative to Ho:YAG lasers. However, further studies are necessary to determine the optimal laser technology for enucleation and lithotripsy of urinary stones, considering all parameters, including efficacy, safety, and cost.

The Effect of High- and Low-power Holmium Laser Settings for Transurethral Lithotripsy in the Management of Adults with Ureteral Stone

Since there is insufficient evidence to determine the best treatment of transurethral laser lithotripsy (TLL) in ureteral stones, this study compared the effectiveness and safety of TLL using high-power (HP) (100 W) and low-power (LP) (20 W) laser settings. All patients with maximally sized ureteral stones who were planned for transurethral holmium laser lithotripsy were enrolled in this open study. One of the two laser setting groups-LP or HP-was allocated to each alternate patient. Using IBM SPSS Statistics 24, the treatment groups were compared for operating time, intraoperative and postoperative problems (up to 1 year), and rates of stone-free recovery. Welch tests were employed to compare continuous data, whereas Fisher's exact or Chi-square tests were used to assess categorical variables. At P < 0.05, statistical significance was established. A total of 207 individuals were included and preoperative data were comparable between the two groups. The HP group had a considerably greater ablation rate and a significantly shorter procedure duration (42.61 ± 11.74 min) than the LP group (78.56 ± 25.91 min) ( P = 0.025). The Overactive Bladder Symptom Score and International Prostate Symptom Score were considerably higher in the HP group than in the LP group. Treatment effectiveness was considerably impacted by the location of the ureteral stone, according to univariate and multivariate logistic regression models. A HP laser setting of up to 100 W greatly shortens the duration of the process for treating ureteral stones without raising the risk of problems.

Advances in lasers for the minimally invasive treatment of upper and lower urinary tract conditions: a systematic review

PURPOSE

Technological advancements in laser lithotripsy are expanding into numerous fields of urology, like ureteroscopy (URS), percutaneous nephrolithotomy (PCNL), and benign and malignant soft-tissue treatments. Since the amount of research regarding lasers in urology has grown exponentially, we present a systematic review of the most recent and relevant advances encompassing all lasers used in urological endoscopic treatment.

METHODS

We performed a literature search using PubMed (May 2023) to obtain information about lasers for urological purposes. We included only recent data from published articles between 2021 and 2023 or articles ahead of print.

RESULTS

Lasers are widely used in lithotripsy for ureteric, renal, and bladder stones, benign prostate surgery, and bladder and upper tract tumor ablation. While the holmium (Ho:YAG) laser is still predominant, there seems to be more emphasis on pulse modulation and newer lasers such as thulium fiber laser (TFL) and pulsed Tm:YAG laser.

CONCLUSION

The use of lasers and related technological innovations have shown increasing versatility, and over time have proven to be invaluable in the management of stone lithotripsy, treatment of benign and malignant prostate diseases, and urothelial tumors. Laser endoscopic treatment is heavily based on technological nuances, and it is essential to know at least the basics of these technologies. Ultimately the choice of laser used depends on its availability, cost, surgeon experience and expertise.

Super pulsed thulium fiber laser outcomes in retrograde intrarenal surgery for ureteral and renal stones: a systematic review and meta-analysis

BACKGROUND

Laser lithotripsy using a thulium fiber laser (TFL) has become an effective treatment option for small renal stones with low complication rates. TFL has a higher absorption coefficient, smaller fibers, and better pulse rate capability.

METHODS

We conducted a systematic review and meta-analysis to evaluate the published evidence regarding TFL's lithotripsy performance in retrograde intrarenal surgery (RIRS), for which we primarily assessed the outcomes of stone-free rate, operation time, and complications. We searched different databases from inception to April 2023. We assessed the methodological quality and risk of bias using the Cochrane Risk of Bias tool for randomized trials and the ROBINS-I tool for non-randomized studies. We used a random-effects model for meta-analysis and assessed heterogeneity using the I2 statistic.

RESULTS

Twelve published studies evaluated the efficacy of RIRS using a TFL for treating renal and ureteral stones. The meta-analysis revealed a predicted stone-free rate of 89.37% (95% CI: 83.93% to 93.12%), indicating that, on average, approximately 89.37% of patients achieved a stone-free state after treatment. The substantial heterogeneity among the studies was evident, as shown by a Q-value of 33.1174 and a p-value of 0.0003. The I2 value of 69.80% (95% CI: 25.91% to 92.02%) highlighted the proportion of variability attributed to genuine heterogeneity across the studies. Moreover, the H2 value 3.31 (95% CI: 1.35 to 12.53) indicated significant heterogeneity beyond random chance. The estimated overall effect size (logit-transformed) of 2.1289 was highly statistically significant (z = 8.7648, p < 0.0001) with a confidence interval of 1.6528 to 2.6049. The reported complications varied across studies, encompassing Clavien grade I-II complications in most cases, with a subset experiencing more severe Clavien grade III-V complications. Additionally, other studies noted a range of complications, such as haematuria, fever, transient creatinine elevation, and postoperative issues like bleeding, pain, and sepsis.

CONCLUSION

This meta-analysis suggests that RIRS using TFL is an effective and safe treatment option for renal and ureteral stones, with high stone-free and low complication rates. The included studies exhibited a low risk of bias and were of high quality. However, more extensive randomized controlled trials with extended follow-up periods are needed to investigate this technique's efficacy and safety.

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.

Prospective Comparison of Thulium and Holmium Laser Lithotripsy for the Treatment of Upper Urinary Tract Lithiasis

Background

Lithotripsy with holmium:yttrium-aluminum-garnet (Ho:YAG) laser is the current gold standard for treating stones of the upper urinary tract (UUT). The recently introduced thulium fiber laser (TFL) has the potential to be more efficient and as safe as Ho:YAG.

Objective

To compare the performance and complications between Ho:YAG and TFL for UUT lithotripsy.

Design setting and participants

This was a prospective single-center study of 182 patients treated between February 2021 and February 2022. In a consecutive approach, laser lithotripsy was performed via ureteroscopy with Ho:YAG for 5 mo, and then with TFL for 5 mo.

Outcome measurements and statistical analysis

Our primary outcome was stone-free (SF) status at 3 mo after ureteroscopy with Ho:YAG versus TFL lithotripsy. Secondary outcomes were complication rates and results regarding the cumulative stone size. Patients were followed at 3 mo with abdominal imaging (ultrasound or computed tomography).

Results and limitations

The study cohort comprised 76 patients treated with Ho:YAG laser and 100 patients treated with TFL. Cumulative stone size was significantly higher in the TFL than in the Ho:YAG group (20.4 vs 14.8 mm; p = 0.01). SF status was similar in both groups (68.4% vs 72%; p = 0.06). Complication rates were comparable. In subgroup analysis, the SF rate was significantly higher (81.6% vs 62.5%; p = 0.04) and the operative time was shorter for stones measuring 1-2 cm, whereas the results were similar for stones <1 cm and >2 cm. The lack of randomization and single-center design are the main limitations of the study.

Conclusions

TFL and Ho:YAG lithotripsy are comparable in terms of the SF rate and safety for the treatment of UUT lithiasis. According to our study, for a cumulative stone size of 1-2 cm, TFL is more effective than Ho:YAG.

Patient summary

We compared the efficiency and safety of two laser types for the treatment of stones in the upper urinary tract. We found that stone-free status at 3 months did not significantly differ between the holmium and thulium lasers.

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.

Retrograde intrarenal surgery: laser showdown (Ho:YAG vs thulium fiber laser)

PURPOSE OF REVIEW

Retrograde intrarenal surgery (RIRS) has always been recommended for large stones > 20 mm, using the Ho:YAG laser. The introduction of a new technology in the urological market, the thulium fiber laser (TFL) has revolutionized the endourology world because of its characteristics and significantly shorter laser-on time (LOT) and operative time, without scarifying the champ vision. The aim of this review is to evaluate the most relevant findings of the last 2 years of each laser technology, confronting Ho:YAG vs TFL, analyzing who is more suitable for performing an efficient RIRS.

RECENT FINDINGS

Five full clinical trials using TFL for RIRS were found. Median LOT was between 2.8 and 34 min. All stones were similar in terms of stone volume, >500 mm3, and stone density, > 800 HU. Low complication rate, mostly Clavien-Dindo grade I and II and not related to the laser itself. One clinical trial only analyzed the efficacy of TFL for > 20 mm renal stones.

SUMMARY

Based on this review, TFL performs a more efficient RIRS than the Ho:YAG laser with similar safety.

Current status of thulium fibre laser lithotripsy: an up-to-date review

OBJECTIVE

To perform an up-to-date review to scope the current status of the thulium fibre laser (TFL) in the setting of stone lithotripsy and provide a guide for the clinical urologist.

METHODS

A review of world literature was performed to identify original articles on TFL for stone lithotripsy. Our clinical experiences of using the technology have also been shared.

RESULTS

To date there have been 11 clinical studies published on TFL for stone lithotripsy. Three of these have been in the setting of miniaturised percutaneous nephrolithotomy (mini-PCNL) and the remainder have been on ureteroscopy (URS). There has only been one randomised study on this technology, which has been for URS. For URS, the range of settings has been 0.1-4 J × 7-300 Hz for both URS and mini-PCNL. Stones ranging from 0.4-3.2 and 1.5-3 cm have been treated with URS and mini-PCNL, respectively. The final stone-free rate for TFL has ranged from 66.6% to 100% and 85-100% for URS and mini-PCNL, respectively. The average length of stay ranged from 0.5 to 2.4 days in the URS group, but no studies have been reported this for mini-PCNL. Operative times in all the studies (both URS and mini PCNL) were <60 min.

CONCLUSION

Initial clinical studies reveal that TFL appears to be efficacious in the setting of stone lithotripsy. However, further randomised trials are warranted to delineate its formal position, as well as determine the optimal settings for use in clinical practice.