Clinical efficacy and safety of flexible ureteroscopic lithotripsy using 365 μm holmium laser for nephrolithiasis: a prospective, randomized, controlled trial

Comparison of clinical effectiveness and safety of 272 µm and 365 µm holmium lasers in retrograde intrarenal surgery

INTRODUCTION

Surgeons typically prefer 270 µm and 272 µm laser probes in retrograde intrarenal surgery (RIRS) due to the reduced deflection capacity of flexible ureterorenoscopes when using larger probe diameters. This study aims to investigate the effects of 272 and 365 µm holmium laser probes on operative time, clinical efficacy, and complication rates in RIRS.

MATERIALS AND METHODS

A total of 285 patients with proximal ureteral or kidney stones who met the inclusion criteria were enrolled in the study. Patients were divided into two groups based on laser probe thickness: 272 µm and 365 µm. Stone-free rates, operative time, and complication rates were compared between the groups. Factors affecting stone-free rates were analyzed using multivariate logistic regression analysis.

RESULTS

Patient and stone characteristics were similar between the two groups. No significant differences were found in stone-free or complication rates. However, operative time was significantly shorter in the 365 µm probe group. In univariate analysis, risk factors for postoperative residual stones included multi-calyceal stones, lower pole stones, high Hounsfield unit (HU) values on non-contrast computed tomography, and larger stone size. In multivariate analysis, independent prognostic factors for residual stones were identified as multi-calycal stones, lower pole stones, and high HU values.

CONCLUSION

Compared to 272 µm laser probes, operative time was shorter in surgeries performed with 365 µm laser probes. The 365 µm holmium laser can be effectively and safely used in the treatment of proximal ureteral and renal stones, demonstrating high clinical efficacy and safety.

Microchannel percutaneous nephrolithotomy versus flexible ureteroscopic lithotripsy for the treatment of 1-2 cm high hardness single upper ureteral stones: a propensity score-matched study

The objective of this study was to compare the clinical efficacy and safety of microchannel percutaneous nephrolithotripsy (MPCNL) with flexible ureteroscopic lithotripsy (FURL) in the treatment of single upper ureteral stones with a diameter of 1-2 cm and high hardness. This study retrospectively analyzed 89 patients diagnosed with a single upper ureteral stone with a 1-2 cm diameter and a computed tomography value > 1000 Hounsfield units. A propensity score matching system matched this study with factors to minimize the effect of baseline differences between patients. Ultimately, 29 patients in each of the two groups were successfully matched. The stone-free rate was marginally higher in the MPCNL group than in the FURL group (93.10% vs. 86.21%), although the difference did not reach statistical significance (P = 0.666). Furthermore, the mean operative time in the MPCNL group, although slightly longer than that in the FURL group, did not demonstrate a statistically significant difference (P = 0.833). However, patients in the MPCNL group exhibited a significantly more substantial decrease in hemoglobin than those in the FURL group (P < 0.001) and a substantially more extended postoperative hospital stay (P < 0.001). Regarding perioperative complications, the incidence of moderate pain was higher in the MPCNL group than in the FURL group (P = 0.037). The difference in overall complication rates between the two groups did not reach statistical significance (P = 0.108). MPCNL and FURL are efficacious surgical procedures for treating single upper ureteral stones with a 1-2 cm diameter and high hardness.

Safety of flexible ureteroscopic lithotripsy with 365 μm fibers of Ho: YAG laser: a short-term follow-up

Our previous study first reported the efficacy of FURL using 365 μm fibers with holmium: yttrium aluminum garnet (Ho: YAG) laser lithotripsy. This study evaluates the 16-week safety of this procedure. A prospective cohort study was conducted, and the clinical characteristics of patients who underwent FURL using 365 μm fibers with Ho: YAG laser were retrospectively collected. Descriptive statistics were reported, and logistic regression analysis was conducted to identify risk factors influencing the stone-free rate (SFR). Infection-related laboratory parameters, including white blood cell count (WBC), procalcitonin (PCT), and C-reactive protein (CRP), were collected. Regression analysis was conducted to identify risk factors for the development of urosepsis post-surgery. Additionally, a 16-week follow-up was conducted in outpatient clinics, and kidney function was assessed. A total of 274 patients participated in this study. The 4-week stone-free rate (SFR) following FURL with 365 μm fibers of Ho: YAG laser was significantly associated with stone size and composition. No severe complications were observed following FURL procedures. There were no significant differences in white blood cell count (WBC), C-reactive protein (CRP), and procalcitonin (PCT) in peripheral blood before and after FURL procedures. Urosepsis was diagnosed in 1.82% of patients. Preoperative white blood cell count (WBC) in urine and preoperative urine culture results were identified as significant risk factors. Kidney function remained stable at 4 and 16 weeks following FURL. This prospective cohort study demonstrated the high safety of FURL with 365 μm fibers of Ho: YAG laser, as infection-related parameters during the perioperative period showed no significant differences, and kidney function remained stable throughout the 16-week follow-up.

The application of intravenous general anesthesia under nasopharyngeal airway assisted ventilation undergoing ureteroscopic holmium laser lithotripsy: A prospective, single-center, controlled trial

To observe the effect of intravenous general anesthesia under nasopharyngeal airway-assisted ventilation on patients undergoing ureteroscopic holmium laser lithotripsy. One hundred and twenty patients who underwent ureteroscopic holmium laser lithotripsy in our hospital were selected and randomly divided into nasopharyngeal airway group (research group) and laryngeal mask group (control group). These patients, respectively, received intravenous anesthesia under nasopharyngeal airway and laryngeal mask-assisted ventilation. The following evaluation indexes were compared and analyzed between the two groups, including anesthetic effect, hemodynamics, stress response, postoperative recovery, adverse reactions, etc. There were no significant differences in Visual Analog Scale, hemodynamics, and stress response between the two groups at each time point (P > 0.05). There were no significant differences in residence time and postoperative recovery time between the two groups (P > 0.05). The difference in airway establishment time between the two groups was statistically significant (P < 0.05), and cases with blood in the research group was significantly lower than those in the control group (P < 0.05). Patient satisfaction in research group was significantly higher than those in the control group (P < 0.05). The clinical effect of intravenous general anesthesia under nasopharyngeal airway-assisted ventilation in ureteroscopic holmium laser lithotripsy is significant, which helps to stabilize patients' hemodynamics, reduce their stress response and adverse reactions, and improve the satisfaction rate of patient.

Percutaneous nephrolithotomy or flexible ureteral lithotripsy, which one is better for patients with upper ureteral calculi of 1.5-2.0 cm in diameter

PURPOSE

First research to evaluate the clinical efficacy and safety of flexible ureteral lithotripsy (FURSL) and percutaneous nephrolithotomy (PCNL) in the treatment of the upper ureteral stone is between 1.5 cm and 2.0 cm in diameter since there is no consensus with such ureteral stone yet.

METHODS

From December 2018 to October 2022, 104 patients with calculi in the upper ureter received percutaneous nephrolithotomy (PCNL)or flexible ureteroscopic lithotripsy (FURSL) in our institution. The clinical data of the patients in the two groups were retrospectively searched. Stone removal rate, operation time, blood loss, postoperative pain score, postoperative inflammatory factor, postoperative complication rates and ureteral obstruction three months after the operation were compared between the two groups.

RESULTS

A total of 104 patients were included in the study. The stone clearance rate and the secondary surgery rate were 88.89% and 7.41% in the FURSL group, the figures were 97.96% and 2.0% in the PCNL group (p = 0.067, 0.497). Regarding ureteral obstruction three months after the operation, there were 2 patients in FURSL group and 0 patients in PCNL group(p = 0.497).Compared to patients in FURSL group, patients in the PCNL group had shorter operation time(PCNL 71.81 ± 18.94 min vs. FURSL 86.80 ± 22.49 min, p = 0.0004), fewer complications(PCNL 20.37% vs. FURSL 6.12%), and lower postoperative inflammatory factor(p = 0.0004), yet they got more hemoglobin drop (PCNL 13.14 ± 9.81 g/L vs. FURSL 4.77 ± 3.55 g/L, p < 0.0001), higher postoperative pain scores(p = 0.0017) in the first three postoperative days and longer hospital stay (PCNL 4.96 ± 1.21 days vs. FURSL 3.60 ± 0.83 days).

CONCLUSION

Both FURSL and PCNL were effective methods for treating upper ureteral stones of 1.5-2.0 cm in diameter given the extremely high stone clearance rate and a very low secondary surgery rate, as long as rare ureteral obstruction in medium-long term observation. Additionally, FURSL can effectively reduce surgical bleeding, postoperative pain, and hospital stay, while PCNL can decrease operation time, the risk of infection, and complications. Therefore, doctors could select suitable surgical treatment for those patients depending on their different clinical situations based on these findings.

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 initial experience of 4.5/6.5 Fr ureteroscopic laser lithotripsy under topical intraurethral anesthesia supplemented by preoperative and intraoperative medications

PURPOSE

To assess the safety and effectiveness of the 4.5/6.5 Fr ureteroscopic laser lithotripsy (URSL) under topical intraurethral anesthesia (TIUA) compared to spinal anesthesia (SA).

METHODS

A retrospective study was conducted on 47 (TIUA: SA = 23:24) patients receiving 4.5/6.5 Fr URSL from July 2022 to September 2022. For the TIUA group, atropine, pethidine, and phloroglucinol were used apart from lidocaine. In the SA group, patients received lidocaine and bupivacaine. We compare the two groups including stone-free rate (SFR), procedure time, anesthesia time, overall operative time, hospital stay, anesthesia failure, intraoperative pain, need for additional analgesia, cost, and complications.

RESULTS

The conversion rate in the TIUA group was 4.35% (1/23). SFR was 100% in both groups. Surgical waiting time and anesthesia time were longer in the SA group (P < 0.001). There were no statistical differences in operational time and intraoperative pain. Patients developed grade 0-1 ureteral injuries. Post-surgical time out of bed was noticeably faster in the TIUA group (P < 0.001). The post-operative complication rate including vomiting and back pain was lower in the TIUA group (P = 0.005).

CONCLUSION

TIUA had an equal surgical success rate and controlled patients' intraoperative pain as SA. It was superior in terms of TIUA's patient admission, waiting time for surgery, anesthesia time, post-operative time out of bed, low complications, and costs, especially for females.

Mutation of Klotho rs3752472 protect the kidney from the renal epithelial cell injury caused by CaOx crystals through the Wnt/β-catenin signaling pathway

Calcium oxalate (CaOx) is a major contributor to urolithiasis, one of the most common urological diseases. Our previous study has shown that Klotho rs3752472 polymorphism correlates with an increased risk of CaOx-related urolithiasis in human cohorts. This study aims to identify the effect of Klotho rs3752472 polymorphism on the renal epithelium injury caused by CaOx. A rat urolithiasis model was established and validated. Renal function was assessed, and histological examination was performed. The distribution and expression of Klotho in the rat model were detected by immunohistochemical staining and western blotting analysis. A renal epithelial cell line (HK2) was used and intervened by COM crystals with several concentrations and time points. Expression of Klotho and key mediators in Wnt/β-catenin pathway were assessed by Western blotting analysis. Wide-type and mutated plasmids of Klotho rs3752472 were added in the cell culture, and the activation of Wnt/β-catenin signaling was tested. Finally, Wide-type and mutated plasmids of Klotho rs3752472 were adoptively transferred to the rat model, and the expression of Klotho was verified. In the rat model, Klotho was mainly distributed in the renal tubular area, which significantly declined in the urolithiasis group. In vitro, COM crystals significantly inhibited the expression of Klotho and induced remarkable renal epithelial cell injury. The mutation of Klotho rs3752472 can notably enhance the expression of Klotho, as well as the protection from renal epithelial cell injury and the inhibition of Wnt/β-catenin signaling pathway. After adoptively transferred to the rat urolithiasis model, similar results were observed for the mutation of Klotho rs3752472. Klotho was significantly correlated with the renal epithelial cell injury induced by CaOx crystals. Furthermore, the mutation of Klotho rs3752472 can remarkably enhance the expression of Klotho in renal tissues and cells, and subsequently protect the renal epithelial cell from the formation of CaOx crystals through the inhibition of Wnt/β-catenin signaling pathway.

The clinical efficacy of novel vacuum suction ureteroscopic lithotripsy in the treatment of upper ureteral calculi

OBJECTIVE

To investigate the clinical efficacy of a novel vacuum suction ureteroscopic approach in the treatment of upper ureteral calculi and to compare it with traditional rigid and flexible ureteroscopic approaches.

SUBJECTS AND METHODS

A total of 160 patients with impacted upper ureteral calculi were included in this study. 50 patients underwent rigid ureteroscopic lithotripsy, 54 patients underwent flexible ureteroscopic lithotripsy, and 56 patients underwent vacuum suction ureteroscopic lithotripsy. The operative time, length of hospitalization, stone-free rate, the incidence of postoperative complications, and total treatment cost were compared among the three groups. Subgroup analysis was performed based on the stone diameter over and below 1.5 cm.

RESULTS

All operations were performed successfully, and there were no cases converted to open surgery. Compared with the other 2 groups, the vacuum suction ureteroscopy group had a higher stone-free rate at 3-5 days (90.0% vs. 61.9% vs. 55.6%, P < 0.05) and 1 month (96.4% vs. 77.7% vs. 74.0%, P < 0.05) postoperatively. In subgroup analysis, the stone-free rate of the vacuum suction ureteroscopy group was significantly higher when the stone diameter was > 1.5 cm at 1 month postoperatively (P < 0.05) compared with that in the other 2 groups; however, there were no differences in postoperative complications. (P > 0.05).

CONCLUSION

The novel vacuum suction ureteroscopic lithotripsy has significantly improved the stone-free rate especially in complicated cases, compared with that in rigid and flexible approaches; however, the complication and cost were not increased.