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

High-frequency in laser lithotripsy: do we truly know what it means?

INTRODUCTION AND OBJECTIVE

High frequency (HF) in laser lithotripsy lacks a consistent definition, potentially impacting clinical outcomes and patient safety. This review aims to analyze available evidence on the definition of HF.

MATERIALS AND METHODS

A comprehensive literature search of MEDLINE, Scopus, and Cochrane databases identified English-language studies published up to November 2024. Those mentioning HF focused on Holmium:YAG (Ho:YAG), Thulium Fiber Laser (TFL), and pulsed Thulium:YAG (p-Tm:YAG) in ureteral and renal endoscopic procedures; in vitro experiments and reviews/editorials were also included. User manuals from high-power laser manufacturers, and data from artificial intelligence (AI) platforms were also analyzed.

RESULTS

From 1030 initial records, 857 studies were screened after duplicate removal, and 106 studies were ultimately included. Most articles came from Europe (46), followed by North America (37) and Asia (20). HF was poorly defined in 25 articles, distributed across Europe (11), North America (7), and Asia (7). Most studies evaluated Ho:YAG (N = 80), followed by TFL (N = 13) and p-Tm:YAG (N = 1); the rest evaluated the first two lasers or all three. HF definitions varied, with European studies reporting ranges from 10 to 200 Hz, North American studies from 10 to 120 Hz, and Asian studies from 10 to 200 Hz. On average, HF ranged from 40 to 50 Hz. Among manufacturers, only four out of eight provided HF definitions in pre-setting/starting guidelines. AI platforms defined HF as 15-100 Hz for Ho:YAG, 50-2000 Hz for TFL, and 20-500 Hz for p-Tm:YAG.

CONCLUSIONS

There is no consensus on HF definitions in laser lithotripsy, with limited manufacturer guidelines and overly broad AI-defined ranges. Standardized terminology is essential. We propose defining HF as > 30 Hz for renal and > 15 Hz for ureteral procedures. Based on the available evidence, the use of HF settings does not appear to be necessary for dusting or popcorning techniques with current technologies.

Outcomes of holmium: YAG laser vs. Thulium fiber laser for ureteric stones during ureterorenoscopic lithotripsy - a prospective, randomized single-centre study

INTRODUCTION

The use of lasers has created a major impact in the management of stones. The aim of our study is to evaluate and compare the effectiveness and safety profile of Thulium fiber laser (TFL) and Holmium: YAG (Ho: YAG) laser in ureteric stones.

METHODS

It is a prospective randomized single-centre study carried out from December 2022 to December 2023. About 110 patients were subjected to the study with 55 randomized to each group. All underwent ureterorenoscopic lithotripsy either with TFL or Ho: YAG laser. Patient demographic data, stone-related factors, and complications were analyzed in both groups and compared.

RESULTS

Mean stone volume was comparable in the Ho: YAG laser and TFL group (578.62 [SD 296.48] mm3 vs. 556.64 [SD 246.18] mm3; P = 0.67). Mean total operative time was significantly different between the two groups (Ho: YAG - 27.3 (SD 2.77) vs. TFL - 24.8 (SD 2.58) minutes, P = 0.005). Mean lasing time was also found to be significantly different (Ho: YAG - 15.16 (SD 3.97) vs. TFL - 13.13 (SD 3.21) minutes, P = 0.004). Ablation speed was also significantly different (Ho: YAG mean 35.67 (SD 9.13) vs. TFL mean 40.48 (SD 10.60) mm3/min, P = 0.012). Stone-free rates (SFR) at 3 months follow-up were similar in TFL and Ho: YAG laser group.

CONCLUSIONS

Shorter lasing time, decreased overall operative time, and higher ablation speed are a few selective advantages of TFL over Ho: YAG laser. The SFR and complication rates remained almost the same in both.

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.

Efficacy and safety of thulium fiber laser versus holmium: yttrium-aluminum-garnet laser in lithotripsy for urolithiasis: a systematic review and meta-analysis

This meta-analysis compares the efficacy and safety of thulium fiber laser (TFL) with holmium: yttrium-aluminum-garnet (Ho: YAG) laser in lithotripsy for urolithiasis. A literature search was conducted across PubMed, Embase, Web of Science, the Cochrane Central Register of Controlled Trials (CENTRAL), and ClinicalTrials.gov to identify studies published up to July 2024. Studies evaluating clinical outcomes for urolithiasis treated with either Ho: YAG laser or TFL were included. The meta-analysis, using RevMan 5.4 software, focused on comparing the stone-free rate (SFR) between the two lasers. A total of 21 studies were included. TFL was associated with a significantly higher SFR (RR 1.09, 95% CI: 1.02 to 1.16; P = 0.01), shorter operation time (SMD - 1.24, 95% CI: -1.82 to -0.66; P < 0.001), shorter lasing time (SMD - 1.26, 95% CI: -1.98 to -0.54; P < 0.001), shorter hospital stay (SMD - 2.08, 95% CI: -4.15 to -0.02; P = 0.05), reduced stone basket usage (SMD 0.50, 95% CI: 0.33 to 0.76; P = 0.001), and a lower total number of intraoperative complications (RR 0.67, 95% CI: 0.47 to 0.96; P = 0.03). However, TFL was also associated with a higher risk of postoperative sepsis (RR 5.32, 95% CI: 1.71 to 16.56; P = 0.004). Subgroup analyses revealed that TFL achieved a higher SFR in several subgroups, including ureteral stones, non-MOSES technology, and follow-up periods of ≥ 3 months, among others. In conclusion, TFL lithotripsy shows superior efficiency and safety compared to the Ho: YAG laser, though the increased risk of postoperative sepsis warrants further investigation.

Efficacy and Safety of Semirigid Ureteroscopy Combined with Holmium:yttrium-aluminum-garnet Laser Lithotripsy for the Treatment of Proximal Ureteral Calculi: A Single-arm Meta-analysis

Background and objective

Ureteral stones are currently treated with holmium:yttrium-aluminum-garnet (Ho:YAG) laser lithotripsy using rigid and flexible ureteroscopes. This study aims to evaluate the efficacy and safety of semirigid ureteroscopy combined with Ho:YAG laser lithotripsy for treating proximal ureteral stones in real-world studies.

Methods

The PubMed, Embase, and Web of Science databases were searched systematically to retrieve all relevant studies up to April 2024. A meta-analysis of the retrieved studies was performed using Stata 14.0 software and expressed as rate, mean difference, and 95% confidence interval (CI). The main outcomes of this meta-analysis were stone-free rate (SFR) and perioperative outcomes including operation time, hospital stay, postoperative ureteral stent placement, auxiliary procedures, and intra- or postoperative complications.

Key findings and limitations

A total of 24 studies were included in this study, including 2058 patients with proximal ureteral stones. According to the results of the combined analysis, the SFR of semirigid ureteroscopy combined with Ho:YAG laser lithotripsy for the treatment of proximal ureteral stones was 78% (95% CI [75%, 82%]), operation time was 51.03 min (95% CI [43.5, 58.56]), hospital stay was 1.62 d (95% CI [1.54, 1.70]), auxiliary procedure rate was 20% (95% CI [15%, 25%]), and postoperative complication rate was 16% (95% CI [12%, 22%]).

Conclusions and clinical implications

The results of this study show that semirigid ureteroscopic Ho:YAG laser lithotripsy is a commonly used treatment for proximal ureteral calculi, but its efficacy and safety need to be improved further, and its efficacy is not related to the diameter of the endoscope.

Patient summary

This study showed that Ho:YAG laser lithotripsy with semirigid ureteroscopes is commonly used for treating ureteral stones. However, its efficacy and safety need to be improved further, and future research should focus on these.

Safety and efficacy of laser lithotripsy for treatment of bladder calculi: evidence from a systematic literature review

PURPOSE OF REVIEW

Bladder stones account for 5% of all urinary tract calculi. Contributing factors include bladder outflow obstruction, infections, foreign bodies, or neurogenic voiding dysfunction. This necessitates an effective treatment modality, and with advances in medical technology, minimally invasive techniques using lasers are being widely adopted. This systematic review aims to assess the efficacy and safety of laser lithotripsy for treating bladder stones.

RECENT FINDINGS

A thorough literature review (PROSPERO: CRD 42024551910) was conducted using appropriate search terms up to March 2024. Only original studies written in English, with at least 10 patients with bladder stones treated with laser, were considered with inclusion. A total of 8 studies (411 patients) were identified on screening with a mean age of 59.6 ± 8.5 years and a male: female ratio of 326 : 14. These reviews covered a geographical area of Asia, Europe, and the USA. The mean stone size was 3.7 ± 0.7 cm, and an overall stone-free rate (SFR) postlaser lithotripsy was 96%. Mean operation time was calculated to be 76.36 ± 47.10 min and an overall complication rate of 16.5% (n = 68), with the most common being haematuria (n = 22), followed by UTI (n = 18), incontinence (n = 8), urosepsis (n = 6), clot retention (n = 4), mucosal injury (n = 3) and urinary retention (n = 3). All complications were minor and there were no Clavien >II complications.

SUMMARY

Laser lithotripsy for bladder stone achieves an excellent success rate in the form of SFR, combined with a low risk of major complications, and allows concomitant treatment of enlarged prostate, and should be considered in all patients.

Ablation efficiency and laser safety of a novel superpulsed thulium fiber laser: a in vitro study

PURPOSE

To assess the ablation efficiency of the Superpulsed Thulium Fiber Laser (SP-TFL) and investigate the thermal effects of SP-TFL.

METHODS

A SP-TFLwas employed to evaluate ablation efficiency. Fresh ex-vivo pig kidneys and ureters were utilized to evaluate the renal pelvis and ureter temperature changes, different irrigation rates(0, 15, 38mL/min) and a long pulse width were used.

RESULTS

The research indicated that as laser output power increased, ablation rates significantly increased. Ablation rates(mg/min) were higher and the energy per ablated mass(J/mg) was lower at lower frequencies(10-50 Hz). Under the same frequency and single pulse energy, super short and short pulse widths demonstrated higher ablation rates at higher frequencies (exceeding 100 Hz). The temperature of the renal pelvis and ureter decreased with increasing irrigation rates. In the renal pelvis, without irrigation, the temperature quickly reached the critical threshold of 43℃. The irrigation rate was 15 ml/min and power was no more than 18 W, the renal pelvis temperature did not reach 43℃. When the irrigation rate were 38 ml/min, the temperature did not risen to 43℃. In the ureter, without irrigation, the temperature also quickly reached 43℃. The temperature reached 43℃ when the power exceeded to12W with an irrigation rate of 15 ml/min. With an irrigation rate of 38 ml/min, the temperature reached 43℃ at a laser power of 30 W.

CONCLUSIONS

The SP-TFL demonstrated promising ablation effectiveness especially for lower frequencies and super short and short pulse widths model. Proper irrigation rates, single pulse energy, frequency and pulse width are crucial during lithotripsy.

Current Status and Prospects of Pediatric Stone Disease: A Bibliometric and Visualization Study

Pediatric stone disease, once considered rare, has emerged as a significant research area in the past two decades due to a sharp increase in its incidence. Understanding the evolving epidemiology and treatment strategies for pediatric stone disease is crucial for enhancing child health protection. This study aims to summarize the advancements in pediatric stone disease research over the last two decades through bibliometric analysis. We conducted a comprehensive search in the Web of Science Core Collection (WoSCC) for literature on pediatric stone disease from January 1, 2000 to February 20, 2024. Econometric analyses were performed using tools such as VOSviewer, CiteSpace, and the R package "bibliometrix." Our search yielded 1,208 publications, predominantly from the United States and Turkey, showing an annual increase in publications on pediatric stone disease. Leading research institutions include Dicle University, Children's Hospital of Philadelphia, and the University of Pennsylvania, with the Journal of Pediatric Urology publishing the highest number of articles. The most prolific authors were C.P. Nelson and B. Hoppe, with Caleb P. Nelson being the most co-cited author. Research themes primarily focused on risk factors and therapeutic approaches for pediatric stone disease. Emerging research hotspots are identified by keywords such as mechanism, mini-percutaneous nephrolithotomy, recurrence, and retrograde intrarenal surgery. The study forecasts a continued upward trend in global research on pediatric stone disease, with future studies likely to delve deeper into risk factors and novel therapeutic methods.

Comparison of Thulium Fiber Laser versus Holmium laser in ureteroscopic lithotripsy: a Meta-analysis and systematic review

OBJECTIVES

To compare the efficacy and safety of thulium fiber laser (TFL) to holmium: YAG (Ho: YAG) laser in ureteroscopic lithotripsy for urolithiasis.

METHODS

PubMed, Web of Science, Embase, CENTRAL, SinoMed, CNKI database, VIP and Wanfang Database were systematically searched for all relevant clinical trials until September 2023. References were explored to identify the relevant articles. Meta-analysis was carried out for the retrieved studies using RevMan5.4.1 software, and the risk ratio, mean difference and 95% confidence interval were expressed. Statistical significance was set at p < 0.05. The main outcomes of this meta-analysis were stone-free rate (SFR), perioperative outcomes and intraoperative or postoperative complications.

RESULTS

Thirteen studies, including 1394 patients, were included. According to the results of pooled analysis, TFL was associated with significantly higher stone-free rate (SFR) [0.52, 95% CI (0.32, 0.85), P = 0.009], shorter operation time [-5.47, 95% CI (-8.86, -2.08), P = 0.002], and less stone migration [0.17, 95% CI (0.06, 0.50), P = 0.001]. However, there was no significant difference in terms of the laser time, duration of hospital stay, drop of hemoglobin level, total energy, postoperative ureteral stenting, the incidence of intraoperative complications or postoperative complications between TFL and Ho: YAGs.

CONCLUSION

The findings of this study demonstrated several advantages of TFL in terms of higher SFR, shorter operative time and less stone migration.

TRIAL REGISTRATION

The protocol of this systematic review was listed in PROSPERO ( www.crd.york.ac.uk/PROSPERO ) (Protocol number: CRD42022362550).

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

BACKGROUND AND OBJECTIVE

We aimed to evaluate the concordance between the pre-settings ranges of thulium fibre laser (TFL) (Coloplast TFL Drive, Denmark) with easy-to-use graphical user interface and the laser settings used by a high-volume endo-urologist during surgical procedures.

MATERIALS AND METHODS

In October 2022, we prospectively collected data of 67 patients who underwent TFL Drive (Coloplast, Denmark) for the management of urinary stones. Urothelial tumour (upper tract urinary cancer (UTUC) and bladder) 200 and 150 μm laser fibres were used for procedures. Stones characteristics (size and density) tumours and stenosis localizations, laser-on time (LOT), and laser settings were recorded. We also assessed the ablation speed (mm3/s), laser power (W), and Joules/mm3 values for each lithotripsy.

RESULTS

A total 67 patients took part in the study. Median age was 52 (15-81) years. 55 (82%), 8 (12%), and 4 (6%) patients presented urinary stones, urothelial tumour, and stenosis, respectively. Median stone volume was 438 (36-6027) mm3 and median density was 988 (376-2000) HU. Median pulse energy was 0.6 (0.3-1.2), 0.8 (0.5-1) and 1 J for urinary stones, urothelial tumour and stenosis respectably. Endoscopically stone-free rate was 89%. Graphical user interface and surgeon accordance with the safety range were observed in 93.2%, 100% and 100% for urinary stones, UTUC and stenosis, respectively.

CONCLUSION

During endoscopic procedures for urinary stones treatment, it is frequently needed to change laser parameters. These new TFL and GUI technology parameters remained in the pre-set security range in 94.1% of procedures.

Paediatric percutaneous nephrolithotomy (P-PCNL) reporting checklist

OBJECTIVE

To develop a reporting checklist that serves to improve and standardise reporting in studies pertaining to paediatric percutaneous nephrolithotomy (PCNL).

METHODS

Based on findings from systematic review of literature, a draft list of items was formulated. By process of review and revisions, a finalised version was established and consensus achieved.

RESULTS

The finalised version of the checklist covers four main sections, which include the following areas: study details, pre-operative, operative and post-operative information. There are 18 further sub-items. Recommendations deemed to be of high importance to include are highlighted in bold.

CONCLUSION

This practical tool can aid clinicians and researchers when undertaking and reviewing studies on paediatric PCNL. This is highly relevant given the current heterogeneity that exists as well as debate in best practice patterns.

Single use flexible ureteroscopes: Current status and future directions

Introduction

Single use ureteroscopes are a technological innovation that have become available in the past decade and gained increased popularity. To this end, there are now an increasing number of both benchside and clinical studies reporting outcomes associated with their use. Our aim was to deliver a narrative review in order to provide an overview of this new technology.

Methods

A narrative review was performed to gain overview of the history of the technology's development, equipment specifications and to highlight potential advantages and disadvantages.

Results

Findings from preclinical studies highlight potenial advantages in terms of the design of single use ureteroscopes such as the lower weight and more recent modifications such as pressure control. However, concerns regarding plastic waste and environmental impact still remain unanswered. Clinical studies reveal them to have a non inferior status for outcomes such as stone free rate. However, the volume of evidence, especially in terms of randomised trials remains limited. From a cost perspective, study conclusions are still conflicting and centres are recommended to perform their own micro cost analyses.

Conclusions

Most clinical outcomes for single use ureteroscopes currently match those achieved by reusable ureteroscopes but the data pool is still limited. Areas of continued debate include their environmental impact and cost efficiency.

Controversies in ureteroscopy: lasers, scopes, ureteral access sheaths, practice patterns and beyond

Ureteroscopy has become an increasingly popular surgical intervention for conditions such as urinary stone disease. As new technologies and techniques become available, debate regarding their proper use has risen. This includes the role of single use ureteroscopes, optimal laser for stone lithotripsy, basketing versus dusting, the impact of ureteral access sheath, the need for safety guidewire, fluoroscopy free URS, imaging and follow up practices are all areas which have generated a lot of debate. This review serves to evaluate each of these issues and provide a balanced conclusion to guide the clinician in their practice.

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.

Thulium fibre laser vs holmium: yttrium-aluminium-garnet laser lithotripsy for urolithiasis: meta-analysis of clinical studies

OBJECTIVE

To compare and assess the clinical outcomes between thulium fibre laser (TFL) and holmium: yttrium-aluminium-garnet (Ho:YAG) laser endoscopic lithotripsy of urolithiasis through a meta-analysis of comparative clinical studies.

METHODS

A systematic literature search was performed in May 2022, grey literature search in July 2022. Comparative clinical studies were evaluated according to Cochrane recommendations. Assessed outcomes include the stone-free rate (SFR), complication rate, operative time (OT), laser utilisation time (LUT), ablation rate (stone volume/laser time), ablation efficiency (energy use/stone volume), total energy usage, degree of retropulsion, and hospital stay. Risk ratios (RRs) and standardised mean differences (SMDs) were extrapolated. Subgroup analyses, heterogeneity, publication bias, and Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) assessment were performed. International Prospective Register of Systematic Reviews (PROSPERO) registration: CRD42022300788.

RESULTS

A total of 15 studies with 1698 cases were included in this review. The outcome of SFR showed no significant between-group difference (RR 1.09, 95% confidence interval [CI] 0.99-1.20). However, subgroup analysis of TFL vs Ho:YAG with no pulse modulation showed a SFR favouring TFL (RR 1.11, 95% CI 1.01-1.23). The composite postoperative complication rate was comparable between the two intervention groups (RR 0.97, 95% CI 0.66-1.43). OT, LUT and ablation rate were significantly better for TFL than Ho:YAG (SMD -1.19, 95% CI -1.85 to -0.52; SMD -1.67, 95% CI -2.62 to -0.72; SMD 0.59, 95% CI 0.15-1.03; respectively). The degree of retropulsion was significantly lower for TFL than Ho:YAG without pulse modulation (SMD -1.23, 95% CI -1.74 to -0.71). Ablation efficiency, total energy usage, and hospital stay were all comparable. Based on GRADE criteria, the evidence certainty was determined to be very low.

CONCLUSION

Overall, there was no between-group difference for the SFR. However, compared to Ho:YAG with no pulse modulation, TFL rendered a better SFR. Shorter OT and LUT, a lesser degree of retropulsion, and a better ablation rate were noted in favour of the TFL. There was no overall between-group difference for composite postoperative complication rate, ablation efficiency, total energy usage, and hospital stay. Currently, the available clinical evidence was assessed to be of very low certainty.

Comparison of Low-Power vs High-Power Holmium lasers in pediatric RIRS outcomes

OBJECTIVES

to compare the outcomes of using low-power (up to 30W) vs high-power (up to 120W) holmium lasers in retrograde intrarenal surgery (RIRS) in children and to analyse if lasering techniques and the use of access sheath have any influence on the outcomes.

METHODS

We retrospectively reviewed data from 9 centres of children who underwent RIRS with holmium laser for the treatment of kidney stones between January 2015 and December 2020. Patients were divided into two groups: high-power and low-power holmium laser. Clinical, perioperative variables and complications were analysed. Outcomes were compared between groups using Student's T-test for continuous variables, and Chi-square and Fisher's exact test for categorical variables. A multivariable logistic regression analysis model was also performed.

RESULTS

314 patients were included. A high-power and low-power holmium laser was used in 97 and 217 patients, respectively. Clinical and demographic variables were comparable between both groups, except for stone size where the low-power group treated larger stones (mean 11.11 mm vs 9.70 mm; p 0.018). In the high-power laser group, a reduction in surgical time was found (mean 64.29 min vs 75.27 min; p 0.018) with a significantly higher stone-free rate (SFR) (mean 81.4% vs 59%; p <0.001). We found no statistical differences in complication rates. The multivariate logistic regression model showed lower SFR in the low-power holmium group, especially with larger (p = 0.011) and multiple stones (p < 0.001).

CONCLUSION

Our real-world pediatric multicenter study favours high-power holmium laser and establishes its safety and efficacy in children.  .

International Alliance of Urolithiasis guideline on retrograde intrarenal surgery

OBJECTIVES

To set out the second in a series of guidelines on the treatment of urolithiasis by the International Alliance of Urolithiasis that concerns retrograde intrarenal surgery (RIRS), with the aim of providing a clinical framework for urologists performing RIRS.

MATERIALS AND METHODS

After a comprehensive search of RIRS-related literature published between 1 January 1964 and 1 October 2021 from the PubMed database, systematic review and assessment were performed to inform a series of recommendations, which were graded using modified GRADE methodology. Additionally, quality of evidence was classified using a modification of the Oxford Centre for Evidence-Based Medicine Levels of Evidence system. Finally, related comments were provided.

RESULTS

A total of 36 recommendations were developed and graded that covered the following topics: indications and contraindications; preoperative imaging; preoperative ureteric stenting; preoperative medications; peri-operative antibiotics; management of antithrombotic therapy; anaesthesia; patient positioning; equipment; lithotripsy; exit strategy; and complications.

CONCLUSION

The series of recommendations regarding RIRS, along with the related commentary and supporting documentation, offered here should help provide safe and effective performance of RIRS.

Paediatric Ureteroscopy (P-URS) reporting checklist: a new tool to aid studies report the essential items on paediatric ureteroscopy for stone disease

The burden of urolithiasis in children is increasing and this is mirrored by the number of surgical interventions in the form of ureteroscopy (URS). There exist many challenges in performing this surgery for this special patient group as well as a lack of consensus on technique. There is also large variation in how results are described and reported. There exists therefore, a need to improve and standardise the core outcomes, which are reported. To this end, we developed a new checklist to aid studies report the essential items on paediatric URS for stone disease. The Paediatric Ureteroscopy (P-URS) reporting checklist comprises four main sections (study details, pre-operative, operative and post-operative) and a total of 20 items. The tool covers a range of important elements, such as pre-stenting, complications, follow-up, stone-free rate, concomitant medical expulsive therapy and imaging, which are often lacking in studies. The checklist provides a summary of essential items that authors can use as a reference to improve general standards of reporting paediatric URS studies and increase the body of knowledge shared accordingly.

Understanding the ablation rate of Holmium:YAG and thulium fiber lasers. Perspectives from an in vitro study

This study sought to analyze the ablation rates of Holmium:YAG (Ho:YAG) and thulium fiber laser (TFL) under different settings combinations. Lasering was carried out by a computed spiral pattern through a stepper motor bearing a laser fiber. BegoStones were placed inside a water container and lasered therein and the ablation rate was calculated. Different combinations were tested for ~12 Watts (W) for Ho:YAG and TFL lasers. Further 25 W combination for TFL were conducted testing higher frequencies. One-hundred-one experiments were conducted. Under ~12 W, the highest ablation rate for Ho:YAG was obtained with 40 Hz/0.3 J, and Virtual Basket™ (VB) emission mode [114.35 (88.30 - 126.40) mg/min] whereas for TFL, using 40 Hz/0.3 J, and long pulse [143.40 (137.40 - 146) mg/min]. A matched-comparison for 12 Hz/1 J settings showed that TFL outperformed Ho:YAG using medium pulse [63.30 (55.30 - 81.30) vs 132.00 (115.70 - 228.60) mg/min, p=0.016] and long pulse [62.90 (51.60 - 78.90) vs 134.70 (110.60 - 149.30) mg/min, p=0.016]. In the 40 Hz/0.3 J settings, TFL outperformed Ho:YAG (p=0.034). Nonetheless, Ho:YAG with VB's ablation rate increased [114.35 (88.30 - 126.40)], being comparable to that of TFL with medium pulse [127.5 (88.90 - 141.70)] (p=0.400). In TFL 25 W experiments, the ablation rate of 500 Hz / 0.05 J, was higher than those of 1000 Hz / 0.025 J (p=0.049). TFL ablation rate is higher than that of Ho:YAG. Moreover, the Virtual Basket™ emission mode, increased Ho:YAG ablation rates, resulting reaching similar to that of TFL in certain modalities.

Paediatric kidney stone surgery: state-of-the-art review

While urolithiasis in children is rare, the global incidence is rising, and the volume of minimally invasive surgeries being performed reflects this. There have been many developments in the technology, which have supported the advancement of these interventions. However, innovation of this kind has also resulted in wide-ranging practice patterns and debate regarding how they should be best implemented. This is in addition to the extra challenges faced when treating stone disease in children where the patient population often has a higher number of comorbidities and for example, the need to avoid risk such as ionising exposure is higher. The overall result is a number of challenges and controversies surrounding many facets of paediatric stone surgery such as imaging choice, follow-up and different treatment options, for example, medical expulsive therapy, shockwave lithotripsy, ureteroscopy, and percutaneous nephrolithotomy. This article provides an overview of the current status of paediatric stone surgery and discussion on the key topics of debate.

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.

Management of Kidney Stone Disease in Pregnancy: A Practical and Evidence-Based Approach

PURPOSE OF REVIEW

Suspected kidney stone disease during pregnancy is a difficult condition for health professionals to manage. This is partly due to the more limited range of diagnostic and therapeutic strategies, which can be safely applied. A comprehensive review of literature was performed to identify evidence to develop a practical guide to aid clinicians.

RECENT FINDINGS

Ultrasound remains the recommended first line option for imaging. Complicated cases, such as suspected infected obstructed system, require urgent decompression such as in the form of percutaneous nephrostomy. This article highlights the pharmacotherapeutic agents, which are considered safe for use in pregnancy. Where surgical intervention is indicated, evidence supports ureteroscopy to be a safe option as long as infection has been treated. Ureteroscopy can offer definitive clearance of the stone(s) and can be less burdensome regarding bothersome symptoms compared to indwelling ureteral stent or nephrostomy, which also require regular exchange due to the high propensity for encrustation in pregnancy. A multidisciplinary approach is fundamental to safely manage suspected kidney stone disease in pregnancy. Adoption of a locally agreed pathway as suggested in this article supports improved patient care.

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.

Advances in Ureteroscopy: New technologies and current innovations in the era of Tailored Endourological Stone Treatment (TEST)

Ureteroscopy has undergone many advances in recent decades. As a result, it is able to treat an increasing range of patient groups including special populations such as pregnancy, anomalous kidneys and extremes of age. Such advances include Holmium laser, high-power systems and pulse modulation. Thulium fibre laser is a more recent introduction to clinical practice. Ureteroscopes have also been improved alongside vision and optics. This article provides an up-to-date guide to these topics as well as disposable scopes, pressure control and developments in operating planning and patient aftercare. These advances allow for a custom strategy to be applied to the individual patient in what we describe using a new term: Tailored endourological stone treatment (TEST).

Level of evidence: 5

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.

Thulium Fibre Laser versus Holmium:YAG for Ureteroscopic Lithotripsy: Outcomes from a Prospective Randomised Clinical Trial

BACKGROUND

Holmium:yttrium-aluminium-garnet (Ho:YAG) laser is the gold standard for ureterorenoscopic (URS) lithotripsy. Thulium fibre laser (TFL) has recently been introduced as a new technology and may challenge Ho:YAG as the preferred laser owing to favourable properties as demonstrated in preclinical studies.

OBJECTIVE

To evaluate and compare outcomes after URS lithotripsy with Ho:YAG and TFL.

DESIGN, SETTING, AND PARTICIPANTS

In a prospective randomised trial, patients aged ≥18 yr with ureteral and/or renal stones (≥5 mm) scheduled to undergo day-case URS lithotripsy were invited to participate. In total, 120 consecutively admitted patients with signed consent were included for randomisation.

INTERVENTION

URS lithotripsy with Ho:YAG or TFL.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome was the stone-free rate (SFR) assessed on noncontrast computed tomography at 3-mo follow-up. Secondary outcomes were the operative time and complications. Outcomes were compared between the groups using the t test and χ² test.

RESULTS AND LIMITATIONS

After a single session, the SFR was 67% in the Ho:YAG group and 92% in the TFL group, p = 0.001. For ureteral stones, the SFR was 100% in both groups, and for renal stones; 49% (Ho:YAG) and 86% (TFL), p = 0.001. Operative time was shorter using TFL (49 min) compared to Ho:YAG (57 min), p = 0.008. Bleeding that impaired the endoscopic view was the most frequent intraoperative adverse event and occurred in 13 patients (22%) in the Ho:YAG group and three (5%) in the TFL group, p = 0.014.

CONCLUSIONS

In this study, significantly more patients with renal stones achieved stone-free status and fewer experienced intraoperative complications using TFL compared to Ho:YAG. TFL is the emerging laser of choice for stone lithotripsy.

PATIENT SUMMARY

We compared outcomes after ureterorenoscopic treatment of kidney and ureteral stones using two different lasers. Our results show that the new thulium fibre laser technology is superior to the current standard laser (holmium:YAG) in clearing kidney stones and reducing operative complications.

Endourological management of encrusted ureteral stents: an up-to-date guide and treatment algorithm on behalf of the European Association of Urology Young Academic Urology Urolithiasis Group

Encrustation of ureteral stents can represent a complex challenge. Patients can require multiple intervention types as well as several operative sessions. Our aim was to establish a practical guide for managing such cases as well as an accompanying treatment algorithm. Nearly all cases can now be successfully managed with minimally invasive methods such as ureteroscopy and/or percutaneous nephrolithotomy. Use of a validated tool for grading burden of encrustation is recommended. Careful patient counselling as well as operative planning are of paramount importance. Identifying high risk patient groups such as pregnancy and implementing prevention strategies are also crucial.