Outcomes of thulium fibre laser for treatment of urinary tract stones: results of a systematic review

Comparative study of thulium fiber laser versus holmium:yttrium-aluminum-garnet laser for ureteric stone management with semi-rigid ureteroscopy: A prospective, single-center study

Objective

To compare the efficacy and safety of thulium fiber laser (TFL) and holmium:yttrium-aluminum-garnet (Ho:YAG) laser for ureteric stone management with semi-rigid ureteroscopy.

Methods

In a prospective study from January 2020 to December 2021, we compared 40 patients in each group who underwent semi-rigid ureteroscopic lithotripsy with TFL and that with Ho:YAG laser. Stone volume, stone density, stone fragmentation rates, total lasing time, total operative time, endoscopic vision, retropulsion and stone free rates were analyzed in both groups and compared.

Results

Mean stone volume was comparable in the TFL group and the Ho:YAG laser group (282.45 [standard deviation, SD 139.79] mm3 vs. 279.49 [SD 312.52] mm3; p=0.964). Mean stone density was also comparable in the TFL group and the Ho:YAG laser group (1135.30 [SD 317.04] Hounsfield unit vs. 1131.75 [SD 283.03] Hounsfield unit; p=0.959). The mean stone fragmentation rates calculated as stone volume divided by lasing time were 25.85 (SD 10.61) mm3/min and 21.37 (SD 14.13) mm3/min in the TFL group and the Ho:YAG laser group, respectively (p=0.113). The mean total lasing time (10.15 [SD] 4.69 min vs. 11.43 [SD 4.56] min; p=0.222), mean operative time (25.13 [SD 9.51] min vs. 25.54 [SD 10.32] min; p=0.866), and mean total hospital stay (2.62 [SD 0.77] days vs. 2.61 [SD 0.84] days; p=0.893) were comparable in the TFL group and in the Ho:YAG group. The vision was better and retropulsion was less in the TFL group. The stone-free rate at 1 month postoperatively was slightly better in the TFL group (100% vs. 90%; p=0.095).

Conclusion

TFL technology was associated with the comparable total surgical time, total lasing time, and stone fragmentation rate with Ho:YAG laser. However, TFL had better endoscopic vision, lesser stone retropulsion, and slightly better stone-free rates.

Successful treatment of staghorn stones with flexible ureteroscopy and thulium fiber laser (TFL) lithotripsy: initial experience with 32 cases

Purpose

To investigate the efficacy and safety of flexible ureteroscopy with thulium fiber laser lithotripsy for management of renal staghorn stones.

Materials and Methods

Thirty-two patients with staghorn stones were recruited. Stone characteristics including: width, length, volume and density were analyzed. Ablation speed, laser efficacy and laser activity were recorded. The primary outcome was to assess stone free rate after the procedure using spiral CT scan.

Results

The median stone volume was 7339 (3183–53838) mm3. Median operative and lasing time were 135 (70–200) and 117 (50–180) minutes, respectively. The mean total energy delivered was 63.9 ± 30 KJ with a median ablation speed of 1.3 (0.5–4.9) mm3/sec. Mean laser efficacy was 7.5 ± 3.6 Joules/mm3. A total of 12 complications occurred in 8 patients (25%). The median hospital stay was 7 (3.5–48) hours and 30 patients (93.7%) were discharged on the same day of surgery. After the first session, seventeen patients (53%) were stone free with no residual fragments while six (19%) patients had residuals £ 2 mm. Nine patients (28%) had residuals > 2 mm with median residual size of 4 (3–9) mm. A second intervention was required in 4 cases.The overall stone free rate after completion of treatment was 65.6%.

Conclusion

Flexible ureteroscopy with thulium fiber laser lithotripsy is a safe and effective treatment option for staghorn stones with stone free rate comparable to standard PCNL with advantages of minimal morbidity, minimal blood loss and shorter hospital stay.

Laser Lithotripsy in Renal Lithiasis - 2023 Update - a Narative Review

INTRODUCTION

Urolithiasis is a serious health issue that is constantly getting worse around the world. In relation to laser lithotripsy, new techniques and technological advancements have emerged, giving urologists a wide range of choices for treating stone disease. The objective of the present review is to provide an overview of the most current developments and show how effective they are for reducing complications and boosting surgical effectiveness.

MATERIAL AND METHOD

In October 2023, we performed a comprehensive search of the literature, including relevant articles using the PubMed international database to identify related publications concerning ureteroscopic laser stone lithotripsy in renal lithiasis. Both review and original articles were selected. Searches were limited to studies written in English which involved human and adult subjects.

RESULTS

All eligible studies concerning ureteroscopic laser lithotripsy were published in 2022 and 2023. They were conducted in Asia (5/10), the North America (3/10) and Europe (2/10), and totalized 1570 patients with an age range between 18 and 85 years. Regarding the primary efficacy outcome, all studies focused on stone free rates (SFRs), complications and average operative time.

CONCLUSION

The rising frequency and incidence of stone disease has led to ongoing breakthroughs in endourology through technological advancements and ongoing developments. Unlike the relatively well-known Holmium laser, which has several uses in the field of stone lithotripsy, Thulium fiber laser (TFL) is a brand-new technological arrangement.

[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.

Safety and Efficacy of "Dusting and Pop-Dusting" with High-Power Laser for Treatment of Large Pediatric Stones with Ureteroscopy and Lasertripsy: Prospective Outcomes from a University Teaching Hospital

Introduction: The wide use of high-power laser has changed the landscape of ureteroscopy and lasertripsy (URSL). We wanted to look at the role and outcomes of high-power holmium:yttrium-aluminum-garnet laser for URSL in pediatric stone disease. Methods: A prospective analysis of consecutive pediatric patients treated with "Dusting and Pop-dusting" using a high-power laser was done between January 2016 and March 2022. The project was registered with our audit committee. Data were analyzed for patient demographics, stone characteristics, operative details, procedural outcomes, and complications. Stone-free rate (SFR) was defined as fragments ≤2 mm on postoperative ultrasound imaging 2-3 months after the procedure. Results: A total of 35 patients underwent 43 procedures (1.2 procedure/patient) during the study period with a mean age of 9.4 years (range 1-16 years) and a male:female ratio of 13:22. The stone location was in the kidney in 32 (91.4%) patients of which 8 were in multiple renal locations. The mean stone size was 18 mm (range 10-39 mm), with the pre- and post-stent rates of 37% and 56%, respectively. An access sheath was used in 19 (44%) procedures. The overall SFR on ultrasound scan was 94% (n = 33) with no procedural complications noted in our series and a mean length of stay of 0.9 days. Conclusion: Pediatric URSL using a high-power laser achieves a high SFR even for large and multiple renal stones with no complications noted in our prospective series. Parents must, however, be counseled about the need for staged procedures, which might be needed for large stones.

Analyzing global research trends and focal points in the utilization of laser techniques for the treatment of urolithiasis from 1978 to 2022: visualization and bibliometric analysis

Laser lithotripsy is gaining global prominence and is a dynamically progressing field marked by a continual influx of new and comprehensive research each year. Recently, there has been a noticeable shift toward the adoption of various kinds of lasers, such as holmium: yttrium-aluminum-garnet (Ho:YAG) and thulium fiber (TFL) lasers. Consequently, we aim to conduct a bibliometric analysis to analyze key areas of research activity within scientific publications that center on the utilization of laser techniques in urolithiasis. A search of the literature spanning from 1978 to 2022 was carried out on 25 December 2023 using the Scopus database to explore research related to the application of laser techniques for urolithiasis treatment. Visualization analysis was performed using VOSviewer software (version 1.6.20). We examined 962 publications that met the specified criteria, 791 (82.22%) of which were original articles. The analysis of the retrieved publications indicated a consistent increase in research output from 1978 to 2022; a particularly noteworthy surge occurred after 2003. In particular, the U.S. claimed the leading position as the most productive country, contributing 211 articles (21.93%). However, India had the highest research productivity according to the adjustment index of 19.08. In the European region, 324 publications (33.68% of the total) originated from 25 countries. The Journal of Endourology contributed the most between 1978 and 2022 (n = 96, 9.98%). The most cited paper examined the effectiveness of holmium: yttrium-aluminum-garnet (Ho:YAG) lasers, while a subsequent study focused on the use of a thulium fiber laser (TFL), an emerging laser technology that has gained increased recognition. Co-occurrence analysis revealed three distinct clusters focusing on the types of laser technology, minimally invasive approaches, and success rate/postoperative complications. This comprehensive investigation delves into the global landscape of laser use for the treatment of urolithiasis. This review supports the emerging clinical concept of using various types of laser technology for urolithiasis treatment. Moreover, the hot issues that researchers should focus on based on the findings of this study are the use of different types of laser lithotripsy in view of the surgical approach, success rate and complications.

Flexible ureteroscopic treatment of kidney stones: How do the new laser systems change our concepts?

Objective

Flexible ureteroscopy (fURS) has become a widely accepted and effective technique for treating kidney stones. With the development of new laser systems, the fURS approach has evolved significantly. This literature review aims to examine the current state of knowledge on fURS treatment of kidney stones, with a particular focus on the impact of the latest laser technologies on clinical outcomes and patient safety.

Methods

We conducted a search of the PubMed/PMC, Web of Science Core Collection, Scopus, Embase (Ovid), and Cochrane Databases for all randomized controlled trial articles on laser lithotripsy in September 2023 without time restriction.

Results

We found a total of 22 relevant pieces of literature. Holmium laser has been used for intracavitary laser lithotripsy for nearly 30 years and has become the golden standard for the treatment of urinary stones. However, the existing holmium laser cannot completely powder the stone, and the retropulsion of the stone after the laser emission and the thermal damage to the tissue have caused many problems for clinicians. The introduction of thulium fiber laser and Moses technology brings highly efficient dusting lithotripsy effect through laser innovation, limiting pulse energy and broadening pulse frequency.

Conclusion

While the holmium:yttrium-aluminum-garnet laser remains the primary choice for endoscopic laser lithotripsy, recent technological advancements hint at a potential new gold standard. Parameter range, retropulsion effect, laser fiber adaptability, and overall system performance demand comprehensive attention. The ablation efficacy of high-pulse-frequency devices relies on precise targeting, which may pose practical challenges.

The Saudi urological association guidelines on urolithiasis

Aims

The Saudi Urolithiasis Guidelines are a set of recommendations for diagnosing, evaluating, and treating urolithiasis in the Saudi population. These guidelines are based on the latest evidence and expert consensus to improve patient outcomes and optimize care delivery. They cover the various aspects of urolithiasis, including risk factors, diagnosis, medical and surgical treatments, and prevention strategies. By following these guidelines, health-care professionals can improve care quality for individuals with urolithiasis in Saudi Arabia.

Panel

The Saudi Urolithiasis Guidelines Panel consists of urologists specialized in endourology with expertise in urolithiasis and consultation with a guideline methodologist. All panelists involved in this document have submitted statements disclosing any potential conflicts of interest.

Methods

The Saudi Guidelines on Urolithiasis were developed by relying primarily on established international guidelines to adopt or adapt the most appropriate guidance for the Saudi context. When necessary, the panel modified the phrasing of recommendations from different sources to ensure consistency within the document. To address areas less well covered in existing guidelines, the panel conducted a directed literature search for high quality evidence published in English, including meta analyses, randomized controlled trials, and prospective nonrandomized comparative studies. The panel also searched for locally relevant studies containing information unique to the Saudi Arabian population. The recommendations are formulated with a direction and strength of recommendation based on GRADE terminology and interpretation while relying on existing summaries of evidence from the existing guidelines.

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.

Which Laser System Is Optimal for Cystolithotripsy of Large Bladder Calculi?

Introduction and Objective: A variety of laser sources are available to treat bladder stones. The aim of this study was to compare time and cost efficiency of the thulium fiber laser (TFL) to four holmium lasers (HLs) with different powers or technologies, including MOSES™ during simulated cystolithotripsy. Materials and Methods: In a benchtop simulation of laser cystolithotripsy, 25 identical 4-cm BegoStones (calcium oxalate monohydrate consistency) were placed on a grid within a 3D-printed bladder model. Lasers were operated at maximal energy, using a 550 μm fiber. Lasers compared were as follows: 60 W TFL, 120 W HL with MOSES, and conventional 120, 100, and 30 W HLs. Five trials were performed for each laser with endpoints of laser time, total time, number of fiber strippings, and total energy. Cost-effectiveness was modeled using laser purchase price, fiber, and operating room (OR) time cost. ANOVA with Tukey's B post hoc was performed to compare outcomes. Spearman's test was used to assess correlation between laser power and procedure time. Results: The laser and total operating times were significantly different between the five systems (p < 0.001). The 120 W HL with MOSES was the fastest with 60.9 minutes of laser and 68.3 minutes of procedure times, while the 30 W HL was the slowest with 281.2 minutes of laser and 297.5 minutes of procedure times. The 60 W TFL was faster than the 30 W HL, but slower than the higher power HLs. Higher laser power was associated with shorter procedure time (Rs = -0.98; p = 0.002). When estimating cost per procedure, the MOSES HL was the cheapest, but had the highest purchase cost. The TFL was not cost-effective for large bladder stones compared with the 100 W HL. Conclusions: When treating large bladder stones, total laser power was highly correlated with laser and procedure times and the TFL was limited by its total power. The most cost-effective laser for use will depend on the case volume.

Thulium Fiber Laser vs Pulse-Modulated Holmium MOSES Laser in Flexible Ureteroscopy for the Management of Kidney Stones: A Single-Center Retrospective Analysis

Introduction and Objective: The study's primary objective was to compare the laser efficiency and clinical outcomes of two widely used systems, the holmium MOSES laser and the thulium fiber laser (TFL), in managing kidney stones. The secondary outcomes were to evaluate the impact of stone composition on laser efficacy. Methods: We conducted a retrospective review of patients who underwent flexible ureteroscopy (f-URS) for solitary renal calculi between December 2020 and August 2022 at our institution and had a 3-month postoperative CT scan. Patient demographics and stone parameters were recorded, including stone site, size, volume, and density. Intraoperative data were collected and analyzed, including total operative time, ureteroscopy time, lasing time, technique, total energy delivered, and stone composition. All patients underwent a CT scan at 3 months follow-up. We recorded the presence of residual stones and the percentage of stone volume reduction. Ablation efficiency was calculated by dividing the energy utilized (J) by the stone volume (mm3). The ablation speed was calculated by dividing the stone volume (mm3) by the lasing time (seconds). Patients with a stone size <4 mm were deemed stone-free. Results: The MOSES and TFL groups comprised 62 and 49 patients, respectively. There were no significant differences between groups for baseline patient demographics or stone characteristics. The two modalities had comparable total energy, laser time, efficacy, and ablation speeds. No differences were detected in stone-free rates or complications between both groups. When dealing with calcium phosphate stones, we observed that the lasing time was significantly shorter with MOSES than TFL (7.95 vs 10.85 minutes, respectively [p = 0.01]). Conclusions: MOSES and TFL laser systems had comparable efficacy for lithotripsy of renal calculi during f-URS; however, calcium phosphate stones had a longer lasing time with TFL. REB Number: 100210.

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.

Innovations in Kidney Stone Removal

Urolithiasis is a common clinical condition, and surgical treatment is performed with different minimally invasive procedures, such as ureteroscopy, shockwave lithotripsy and percutaneous nephrolithotomy. Although the transition from open surgery to endourological procedures to treat this condition has been a paradigm shift, ongoing technological advancements have permitted further improvement of clinical outcomes with the development of modern equipment. Such innovations in kidney stone removal are new lasers, modern ureteroscopes, development of applications and training systems utilizing three-dimensional models, artificial intelligence and virtual reality, implementation of robotic systems, sheaths connected to vacuum devices and new types of lithotripters. Innovations in kidney stone removal have led to an exciting new era of endourological options for patients and clinicians alike.

Indications, preferences, global practice patterns and outcomes in retrograde intrarenal surgery (RIRS) for renal stones in adults: results from a multicenter database of 6669 patients of the global FLEXible ureteroscopy Outcomes Registry (FLEXOR)

PURPOSE

To collect a multicentric database on behalf of TOWER research group to assess practice patterns and outcomes of retrograde intrarenal surgery (RIRS) for kidney stones.

METHODS

Inclusion criteria: age ≥ 18 years, normal renal/calyceal system anatomy, calculi of any size, number, and position.

STUDY PERIOD

January 2018 and August 2021. Stone-free status: absence of fragments > 2 mm, assessed post procedure according to the local protocol (KUB X-Ray and/or ultrasound or non-contrast CT scan).

RESULTS

Twenty centers from fifteen countries enrolled 6669 patients. There were 4407 (66.2%) men. Mean age was 49.3 ± 15.59 years. Pain was the most frequent symptom indication for intervention (62.6%). 679 (10.2%) patients underwent RIRS for an incidental finding of stones. 2732 (41.0%) patients had multiple stones. Mean stone size was 10.04 ± 6.84 mm. A reusable flexible ureteroscope was used in 4803 (72.0%) procedures. A sheath-less RIRS was performed in 454 (6.8%) cases. Holmium:YAG laser was used in 4878 (73.1%) cases. A combination of dusting and fragmentation was the most common lithotripsy mode performed (64.3%). Mean operation time was 62.40 ± 17.76 min. 119 (1.8%) patients had an intraoperative injury of the ureter due to UAS insertion. Mean postoperative stay was 3.62 ± 3.47 days. At least one postoperative complication occurred in 535 (8.0%) patients. Sepsis requiring intensive care admission occurred in 84 (1.3%) patients. Residual fragments were detected in 1445 (21.7%) patients. Among the latter, 744 (51.5%) patients required a further intervention.

CONCLUSION

Our database contributes real-world data to support to a better understanding of modern RIRS practice and outcomes.

Laser Efficiency and Laser Safety: Holmium YAG vs. Thulium Fiber Laser

(1) Objective: To support the efficacy and safety of a range of thulium fiber laser (TFL) pre-set parameters for laser lithotripsy: the efficiency is compared against the Holmium:YAG (Ho:YAG) laser in the hands of juniors and experienced urologists using an in vitro ureteral model; the ureteral damage of both lasers is evaluated in an in vivo porcine model. (2) Materials and Methods: Ho:YAG laser technology and TFL technology, with a 200 µm core-diameter laser fibers in an in vitro saline ureteral model were used. Each participant performed 12 laser sessions. Each session included a 3-min lasering of stone phantoms (Begostone) with each laser technology in six different pre-settings retained from the Coloplast TFL Drive user interface pre-settings, for stone dusting: 0.5 J/10 Hz, 0.5 J/20 Hz, 0.7 J/10 Hz, 0.7 J/20 Hz, 1 J/12 Hz and 1 J/20 Hz. Both lasers were also used in three in vivo porcine models, lasering up to 20 W and 12 W in the renal pelvis and the ureter, respectively. Temperature was continuously recorded. After 3 weeks, a second look was done to verify the integrity of the ureters and kidney and an anatomopathological analysis was performed. (3) Results: Regarding laser lithotripsy efficiency, after 3 min of continuous lasering, the overall ablation rate (AR) percentage was 27% greater with the TFL technology (p < 0.0001). The energy per ablated mass [J/mg] was 24% lower when using the TFL (p < 0.0001). While junior urologists performed worse than seniors in all tests, they performed better when using the TFL than Ho:YAG technology (36% more AR and 36% fewer J/mg). In the in vivo porcine model, no urothelial damage was observed for both laser technologies, neither endoscopically during lasering, three weeks later, nor in the pathological test. (4) Conclusions: By using Coloplast TFL Drive GUI pre-set, TFL lithotripsy efficiency is higher than Ho:YAG laser, even in unexperienced hands. Concerning urothelial damage, both laser technologies with low power present no lesions.

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.

Comparison and outcomes of dusting versus stone fragmentation and extraction in retrograde intrarenal surgery: results of a systematic review and meta-analysis

INTRODUCTION

Lithotripsy during retrograde intrarenal surgery (RIRS) can be achieved either by fragmentation and extraction or dusting with spontaneous passage. We aimed to perform a systematic review on the safety and stone-free rate after RIRS by comparing the techniques of dusting vs fragmentation/extraction.

MATERIAL AND METHODS

This review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses statement. The inverse variance of the mean difference and 95% Confidence Interval (CI), Categorical variables were assessed using Cochran-Mantel-Haenszel Method with the random effect model and reported as Odds Ratio (OR) and 95% CI. Statistical significance was set at p <0.05.

RESULTS

There were 1141 patients included in 10 studies. Stone size was up to 2.5 cm All studies used holmium laser for lithotripsy. Meta-analysis showed no significant difference in surgical time (MD -5.39 minutes 95% CI -13.92-2.31, p = 0.16), postoperative length of stay (MD -0.19 days 95% CI -0.60 - -0.22, p=0.36), overall complications (OR 0.98 95% CI 0.58-1.66, p = 0.95), hematuria (OR 1.01 95% CI 0.30-3.42, p = 0.99), postoperative fever (OR 0.70 95% CI 0.41-1.19, p = 0.19) and sepsis (OR 1.03 95% CI 0.10-10.35, p = 0.98), immediate (OR 0.40 95% CI 0.13-1.24, p = 0.11) and overall stone-free rate (OR 0.76 95% CI 0.43-1.32, p = 0.33), and retreatment rate (OR 1.35 95% CI 0.57-3.20, p = 0.49) between the groups.

CONCLUSIONS

This systematic review infers that urologists can safely use either option of fragmentation and basket extraction or dusting without extraction to achieve similar outcomes as both techniques are similar for efficacy and safety.

NO Residual Stones after Flexible Ureteroscopy for Renal Stones - Update 2021. A Narrative Brief Review

Urolithiasis is a major health problem which is on the rise worldwide. New procedures and technological tools have arisen, providing the urologist with a vast arsenal of options for stone disease management. The goal of this narrative review is to summarize the most recent advancements and demonstrate their efficacy in reducing complications and increasing surgical efficacy. The latest modern advances in increasing stone rate after flexible ureteroscopy were included. The ureteral access sheet concept represents one of the most important parts in this procedure and new performances achieved in this field like suction and pressure control were evaluated. Another important aspect in flexible ureteroscopy is related to laser fibres. The latest achievements in Holmium and Thulium fibres were analysed and compared using both dusting and fragmenting techniques. After analysing these aspects, the conclusion was that suction improved visualization by removing "stone storm" and bleeding during the procedure and Thulium laser had the potential to become the new "gold standard" in the pursuit of obtaining a higher stone free rate.

Is There Still a Place for Percutaneous Nephrolithotomy in Current Times?

Background: Percutaneous nephrolithotomy (PCNL) and its miniaturized modifications are usually considered the standard surgical options for large (>20 mm) staghorn and infected stones. Moreover, PCNL is a viable alternative to retrograde intrarenal surgery (RIRS) for smaller stones (<20 mm) in the presence of anatomical malformations or inaccessible lower pole stones. However, due to the advancements in laser and scope technology, RIRS is expanding its indications with the potential benefits of lower complications and a shorter hospital stay. Methods: A literature search using the PUBMED database from inception to June 2022 was performed to explore the current role of PCNL in endourology. The analysis involved a narrative synthesis. Results: PCNL confirmed its role in the treatment of large and complex stones; moreover, miniaturized PCNL has become more competitive, gaining space among classic indications of flexible ureteroscopy. Conclusions: considering all the evaluated subgroups, we can conclude that PCNL is an old fascinating procedure and is here to stay.

A comparison among RIRS and MiniPerc for renal stones between 10 and 20 mm using thulium fiber laser (Fiber Dust): a randomized controlled trial

PURPOSE

We performed a prospective randomized comparison among Retrograde IntraRenal Surgery (RIRS) and MiniPerc (MP) for stones between 10 and 20 mm to evaluate outcomes with the same laser device: Fiber Dust.

METHODS

Patients with a single renal stone between 10 and 20 mm were randomized to RIRS (Group A) versus MP (Group B). Exclusion criteria were age < 18 or > 75, presence of acute infection, coagulation impairments, cardiovascular or pulmonary comorbidities. In both groups, the Fiber Dust laser was used. A CT scan after 3 months was performed. A negative CT scan or asymptomatic patients with stone fragments < 3 mm and a negative urinary culture were the criteria to assess the stone-free status. A statistical analysis was carried out to assess success, complication and retreatment rates and need for auxiliary treatments.

RESULTS

Between January 2021 and January 2022, 186 patients were enrolled (90 in Group A and 96 in Group B). Mean stone size was 15.8 mm and 14.9 mm in Group A and B, respectively (p = 0.23). The overall stone-free rate (SFR) was 73.3% for Group A and 84.4% for Group B. A higher SFR was reached for upper calyceal stones in Group A (90.4%) lower calyceal stones in Group B (91.6%). Retreatment rate (p = 0.31) and auxiliary procedure rate (p = 0.18) were comparable. Complication rate was 5.5% and 5.2% for Groups A and B, respectively.

CONCLUSIONS

RIRS and MP are both effective to obtain a postoperative SFR with Fiber Dust. According to the stone position one treatment is superior to the other one.

Temperature profiles during ureteroscopy with thulium fiber laser and holmium:YAG laser: Findings from a pre-clinical study

OBJECTIVE

The aim of this study was to investigate temperature profiles in both the renal pelvis and parenchyma during Thulium Fiber Laser (TFL) and Holmium:yttrium-aluminium-garnet (Ho:YAG) laser activation in an ex-vivo porcine model.

METHODS

Three porcine kidneys with intact renal pelvis and proximal ureters were used in the study. A temperature sensor was inserted through a nephrostomy tube into the renal pelvis and a second sensor was inserted directly into the renal parenchyma. Temperatures were recorded during continuous laser activation for 180 s, and for an additional 60 s after deactivation. TFL (150 μm and 200 μm) and Ho:YAG (270 μm) laser delivered power at settings of 2.4 W, 8 W, 20 W and 30 W.

RESULTS

Intrapelvic temperatures correlated directly to power settings. Higher power produced higher temperatures. For example, using a 150 μm fiber at 2.4 W resulted in a 2.6 °C rise from baseline (p = 0.008), whereas using the same fiber at 20 W produced a rise in temperature of 19.9 °C (p = 0.02). Larger laser fibers caused significantly higher temperatures compared to smaller fibers using equivalent power settings, e.g. mean temperature at 20 W using 150 μm was 39.6 °C compared to 44.9 °C using 200 μm, p < 0.001. There was a significant increase in parenchymal temperatures when applying 20 W and 30 W of laser power with the two larger fibers.

CONCLUSION

In this ex-vivo study, renal temperatures correlated directly to power settings. Higher power produced higher temperatures. Furthermore, larger laser fibers caused higher temperatures. These findings could help guide selection of safe power settings for ureteroscopic lithotripsy, but future clinical studies are needed for confirmation.

Theoretical and experimental evaluation of the distance dependence of fiber-based fluorescence and reflection measurements for laser lithotripsy

OBJECTIVES

In laser lithotripsy, a green aiming beam overlying the infrared (IR) treatment radiation gives rise to reflection and fluorescence signals that can be measured via the treatment fiber. While stone autofluorescence is used for target detection, the condition of the fiber can be assessed based on its Fresnel reflection. For good applicability, fluorescence detection of stones should work even when the stone and fiber are not in direct contact. Fiber breakage detection, on the other hand, can be falsified if surfaces located in front of the fiber reflect light from the aiming laser back into it. For both applications, therefore, a fundamental investigation of the dependence of the signal amplitude on the distance between fiber and surface is important.

METHODS

Calculations of the signal drop of fluorescence or diffuse and specular reflection with increasing fiber distance were performed using ray tracing based on a simple geometric model for different fiber core diameters. Reflection signals from a mirror, diffuse reflector, human calculi, and porcine renal tissue placed in water were measured at varying distances (0 - 5 mm). For human calculi, fluorescence signals were recorded simultaneously.

RESULTS

The calculations showed a linear signal decrease down to ~60% of the maximum signal (fiber in contact). The distance z at which the signal drops to for example 50% depends linearly on the diameter of the fiber core. For fibers used in lithotripsy and positioned in water,z_50%ranges from 0.55 mm (200 µm core diameter) to 2.73 mm (1 mm core diameter). The calculations were in good agreement with the experimental results.

CONCLUSIONS

The autofluorescence signals of stones can be measured in non-contact mode. Evaluating the Fresnel signal of the end face of the fiber to detect breakage is possible unless the fiber is situated less than some millimeters to reflecting surfaces.

Lithotripsy devices for percutaneous nephrolithotomy (PNL) - new developments

PURPOSE OF REVIEW

Percutaneous nephrolithotomy (PNL) is the mainstay of surgery for renal calculi>2 cm or complex multiple calculi and is a technique that has been around since 1976. We review recent literature surrounding novel lithotripsy devices and technology used in PNL.

RECENT FINDINGS

At present, the Holmium:yttrium-aluminum-garnet (Ho:YAG) laser is widely accepted as the gold standard laser lithotripsy for PNL. SwissLithoClast Trilogy offers a range of probes with a trifecta of electromagnetic, ultrasonic energy with surgeon-controlled suction. The Olympus Shockpulse-SE is a similar lithotripter that relies on continuous ultrasonic energy with pulsed ballistic energy to break stones. Thulium Fiber Laser (TFL) offers an alternative laser energy source to the Holmium laser, which has been shown to be very effective at producing small stone fragments and dust. The Moses technology is another addition in a long list of improvements to the Ho:YAG laser, forming vaporization bubble through which more effective energy can be applied to stones.

SUMMARY

Trilogy, Shockpulse, TFL and Moses pulse modulation technology for the Holmium laser all provide improvements compared with older lithotripsy devices. In particular, they convey a safer, efficient and more effective way to manage and clear stones.

The future of laser technology in kidney stones

PURPOSE OF REVIEW

The aim of this study was to present the recent and promising innovations of the new laser technologies used for the treatment of renal stones.

RECENT FINDINGS

Taking advantage of pulse modulation, new technologies such as the Moses effect, the Virtual basket and the Vapor tunnel have been introduced. These technologies seem to improve lithotripsy efficacy by reducing retropulsion and increasing the stone ablation rate.High-power laser lithotripsy has arisen in everyday clinical practice in some centres. The combination of equal efficacy and safety levels compared with the low-power laser lithotripsy and significantly reduced operative time could explain this trend.Thulium fibre laser is an innovative type of laser-emitting machine that offers a lot of advantages compared with its predecessors. The different mechanism of creating the laser pulse offers new possibilities in laser lithotripsy and perhaps in the future thulium fibre laser could replace Ho:YAG as the golden standard for laser lithotripsy.

SUMMARY

Laser lithotripsy is heavily based on technological equipment. The continuous improvement of available lasers increases the endoscopic lithotripsy levels of efficacy and safety.

Wavelength-stabilized tunable mode-locked thulium-doped fiber laser beyond 2 µm

We report the development of a widely tunable mode-locked thulium-doped fiber laser based on a robust chirped fiber Bragg grating (CFBG). By applying mechanical tension and compression to the CFBG, an overall tunability of 20.1 nm, spanning from 2022.1 nm to 2042.2 nm, was achieved. The observed mode-locked pulse train from this fiber laser has a repetition rate of 9.4 MHz with an average power of 12.6 dBm and a pulse duration between 9.0 ps and 12.8 ps, depending on the central wavelength. To the best of our knowledge, this is the first demonstration of a tunable mode-locked thulium-doped fiber laser operating beyond 2 µm using a CFBG as a wavelength-selective element.

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.

Thulium fiber laser versus holmium:yttrium aluminum garnet laser for stone lithotripsy during mini-percutaneous nephrolithotomy: A prospective randomized trial

INTRODUCTION

We aimed to evaluate the effectiveness and safety of the newly launched thulium fiber laser (TFL) with holmium laser lithotripsy in the miniaturized percutaneous nephrolithotomy (Miniperc) procedure for renal stones.

METHODS

The prospective study included patients with renal stones of size >1 cm to ≤3 cm. The patients who opted for extracorporeal shock wave lithotripsy, retrograde intrarenal surgeries, and stones >3 cm were excluded from the study. Demographics such as patient's age, sex, stone volume, and hardness were evaluated. The patients were randomized into holmium and TFL group for stone lithotripsy. Both the procedures were evaluated for stone disintegration time, operative time, hospital stay, intra- and postoperative complications, and stone-free rate.

RESULTS

A total of 125 patients with renal stones who underwent Miniperc were included in this study. The average size of the stone was comparable in both the groups (P = 0.053). The median stone disintegration time with holmium laser was 20 min 45 s and with TFL, it was 11 min 19 s (P < 0.001). The most common complications were Clavien grade I and II complications (P = 0.128). Prolonged postoperative hematuria was observed in the Thulium fiber laser group, which was conservatively managed. The stone-free rate with TFL (94.9%) was better than Holmium lithotripsy (90.9%).

CONCLUSIONS

The TFL has significant less stone disintegration time which effectively reduced the operative time of Miniperc procedure. The stone-free rate is better, but the incidence of self-limiting hematuria is higher with TFL as compared to Holmium laser.

A prospective comparative study of mini-PCNL using Trilogy™ or thulium fibre laser with suction

INTRODUCTION

There has been recent introduction of novel lithotripters and high-power lasers for stone disintegration. With miniaturization of PCNL, there is need of effective disintegration and faster stone-clearance. This study aimed to evaluate efficiency of Trilogy™ and Thulium fibre laser (TFL) in mini-percutaneous nephrolithotomy (mini-PCNL).

METHODS

This is prospective study comparing efficiency and outcomes of Trilogy™ and TFL in mini-PCNL between January 2019 and February 2020. Primary objective was to compare stone fragmentation rates, with secondary objectives beings stone-free rates and complications.

RESULTS

There were 60 mini-PCNL with suction using either Trilogy™ or TFL energy source. Mean stone size and density were 27.60 ± 10.17 mm, 22.04 ± 9.69 mm (p = 0.05) and 1172.9 ± 313.5HU, 1308.9 ± 333.9HU (p = 0.10) for Trilogy™ and TFL, respectively. Using 3D doctor imaging software from CT images, mean stone volumes were 3718.9 ± 3038.7mm³ for Trilogy™ and 3425.9 ± 3096.1mm³ for TFL(p = 0.77). Using probe-activation time or lasing time, stone-fragmentation rate was 5.98 ± 4.25mm³/sec for Trilogy™ and 3.95 ± 1.00mm³/sec for TFL(p = 0.015). Treatment time (puncture to complete clearance) was 32.48 ± 15.39 min for Trilogy™ and 28.63 ± 18.56 min for TFL(p = 0.38). Haemoglobin drop was 1.19 ± 0.76gm/dl for Trilogy™ and 0.99 ± 0.74gm/dl for TFL (p = 0.30). Trilogy™ arm had 96.6% complete clearance and TFL had 76.6% in TFL at 48 h. One patient in Trilogy™ arm required auxiliary RIRS for residual stone. Both arms had complete stone clearance at 1 month follow-up. Trilogy™ arm had 3 Clavien-Dindo grade-II complications while TFL had 2 Clavien-Dindo grade-II complications (UTI requiring antibiotics). There was no blood transfusion in either of arm.

CONCLUSION

Trilogy™ had significantly better stone fragmentation rate than TFL in managing renal stones. However, stone-free rates and complications were comparable for Trilogy™ and TFL.

New Lasers for Stone Treatment

Laser technology has been a breakthrough in urology. The new era in endocorporeal laser lithotripsy has recently begun in mid-2020, where promising technologies tested in vitro have reached their approval for clinical use and, in that way, have made it possible to confirm their safety and advantages in the real world, for the patient and for the urologist.

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.

A Systematic Review of Thulium Fiber Laser: Applications and Advantages of Laser Technology in the Field of Urology

Laser technology is widely used in urological surgery, from lithotripsy, prostate surgery to en-bloc resection of tumours. While Holmium:YAG has been widely employed over the last two decades, in recent years, there has been a surge of interest in Thulium Fiber Laser (TFL), which offers theoretical advantages of better water absorption and lower stone ablation thresholds. A systematic review was conducted to assess the evidence from clinical research on TFL's application for lithotripsy and prostate surgery. It identified 357 articles and 8 (1506 patients) were selected, of which 4 clinical studies each investigated TFL enucleation of prostate (ThuFLEP) and TFL lithotripsy. For flexible ureteroscopic lithotripsy (FURSL), stone ablation settings ranged from 0.1-4 J, and 7-300 Hz, mean operative time ranged from 23.4-39.8 minutes and lasing time ranged from 1.2-10 minutes. For stone dusting in percutaneous nephrolithotomy (PCNL), settings of 0.2 J and 125-200 Hz were found to be optimal. For ThuFLEP, all studies showed a significant improvement in IPSS (International Prostate Symptom Score), urinary flow rate (Qmax), quality of life measures, and post-void residual volume, with mean operative time ranging from 67-104.5 minutes. Our review shows that there is limited evidence on the use and clinical outcomes of TFL. ThuFLEP might suggest equivalence to the widely used HoLEP in the available evidence so far. TFL lithotripsy shows promising results but further prospective, randomized trials are required to properly assess its usability, clinical effectiveness and standardisation of the settings for successful adoption of the technology.

Outcomes of Ureteroscopy and Laser Stone Fragmentation (URSL) for Kidney Stone Disease (KSD): Comparative Cohort Study Using MOSES Technology 60 W Laser System versus Regular Holmium 20 W Laser

Background: For ureteroscopy and laser stone fragmentation (URSL), the use of laser technology has shifted from low power to higher power lasers and the addition of Moses technology, that allows for ‘fragmentation, dusting and pop-dusting’ of stones. We wanted to compare the outcomes of URSL for Moses technology 60 W laser system versus matched regular Holmium 20 W laser cases. Methods: Prospective data were collected for patients who underwent URSL using a Moses 60 W laser (Group A) and matched to historical control data using a regular Holmium 20 W laser (Group B), performed by a single surgeon. Data were collected for patient demographics, stone location, size, pre- and post-operative stent, operative time, length of stay, complications and stone free rate (SFR). Results: A total of 38 patients in each group underwent the URSL procedure. The stones were matched for their location (17 renal and 11 ureteric stones). The mean single and cumulative stone sizes (mm) were 10.9 ± 4.4 and 15.5 ± 9.9, and 11.8 ± 4.0 and 16.5 ± 11.3 for groups A and B, respectively. The mean operative time (min) was 51.6 ± 17.1 and 82.1 ± 27.0 (p ≤ 0.0001) for groups A and B. The initial SFR was 97.3% and 81.6% for groups A and B, respectively (p = 0.05), with 1 and 7 patients in each group needing a second procedure (p = 0.05), for a final SFR of 100% and 97.3%. While there were 2 and 5 Clavien I/II complications for groups A and B, none of the patients in group A had any infection related complication. Conclusions: Use of Moses technology with higher power was significantly faster for stone lithotripsy and reduced operative time and the number of patients who needed a second procedure to achieve a stone free status. It seems that the use of Moses technology with a mid-power laser is likely to set a new benchmark for treating complex stones, without the need for secondary procedures in most patients.