Flexible ureteroscopy and laser lithotripsy for renal stones 2 cm or greater: A single institutional experience

Comparison of conventional (basketing + dusting) and Moses (pop-dusting) holmium lasers during flexible ureteroscopy in the treatment of renal stones between 2 and 3 cm: a randomized clinical trial

To investigate the feasibility of conventional (basketing + dusting) and Moses (pop-dusting) holmium lasers during flexible ureteroscopy (FURS) in the treatment of 2-3 cm renal calculi and to compare the efficiency and safety of the two methods, a total of 230 patients with 2-3 cm kidney stones who underwent FURS were randomly divided into the conventional group and the Moses group. The mode of lithotripsy in the conventional group was fragmentation and dusting. The mode of lithotripsy in the Moses group was dusting and pop-dusting. Clinical and perioperative variables and complications were compared between the two cohorts. Multivariate analyses of factors contributing to the stone-free rate (SFR) and operation time were performed. No statistically significant differences were found in the demographics, renal stone-related data, SFR, or complications between the cohorts. The laser energy was higher in the Moses cohort than in the conventional cohort (119.3 ± 15.2 vs. 92.8 ± 15.1 kJ; P < 0.001), and the operation time was shorter in the Moses cohort than in the conventional cohort (99.5 ± 18.9 vs. 105.3 ± 13.7 min; P = 0.009). When there was isolated stone, the operation time was shorter in the Moses cohort than in the conventional cohort (99.6 ± 17.5 vs. 111.4 ± 10.7 min; P < 0.001), while there was no significant difference between the two cohorts when there were multiple stones (99.5 ± 20 vs. 101.2 ± 14 min; P = 0.415). Multivariate analyses found that an increase in stone volume can decrease the SFR and prolong the operation time, and use of a Moses laser can shorten the operation time. Both holmium laser modes during FURS can effectively treat 2-3 cm renal calculi. The Moses mode is recommended as the first choice for the treatment of isolated 2-3 cm renal stones. When treating multiple stones, the efficiency of these two laser modalities is the same. TRIAL REGISTRATION: ChiCTR2200056091.

Comparison of high and low pulse energy dusting protocols using holmium: YAG laser in flexible ureteroscopy for treatment of renal stones

Objectives

The management of renal stones, particularly those less than 2 cm in diameter, has changed with the development of endourological techniques, among which flexible ureteroscopy (FURS) using laser for lithotripsy has become a cornerstone. This study aims to compare the effectiveness of high pulse energy versus low pulse energy laser settings in renal stone dusting by Holmium YAG laser.

Patients and Methods

This prospective randomized study was conducted between September 2021 and November 2023 to compare the efficacy and safety of high energy versus low-energy pulse settings using a Holmium: YAG laser dusting of renal stones less than 2 cm in diameter. A total of 174 adult patients were included, divided equally into high- and low-pulse energy groups, based on the energy settings of the laser high energy (ranged from 1.2-2.5 Joules and frequency of 8 hz) and low energy (less than 0.5 Joules and frequency ≥ 15 hz) using the dusting ‎technique with non-touch non-stop approach. The study sought to evaluate the impact of these settings on stone fragmentation efficiency, operative time, laser energy consumption, and postoperative outcomes, including stone-free rates and complications.

Results

The study involved 174 patients who underwent renal stone lithotripsy and showed that using high pulse energy laser dusting settings significantly reduced operative times and more rapid dusting compared to low pulse energy settings, without affecting the stone-free rate. The study observed no significant differences in stone size or location between both groups. Minor postoperative complications were similar between both groups, indicating high pulse energy settings for lithotripsy dusting.

Conclusion

The efficacy of high pulse energy dusting in enhancing stone removal during surgery, potentially reducing operative time. Further validation through larger-scale studies is needed to solidify these findings. This technique presents a promising solution, particularly in regions with limited resources where acquiring expensive laser equipment is challenging.

The outcomes of flexible ureteroscopy for renal calculi of 2 cm or more with and without the use of ureteral access sheath: A retrospective study

INTRODUCTION

The rate of success of retrograde intrarenal surgery (RIRS) for treating urinary tract stones is high, and the procedure is growing in popularity. The routine use of ureteral access sheath (UAS) remains somewhat controversial. The aim of this study was to assess the efficacy and safety of employing UAS during flexible ureteroscopy for treating renal stones ≥ 2 cm.

METHODS

This retrospective study was accomplished from January 2021 to February 2023. From 495 consecutives flexible ureteroscopies, 112 patients had renal stones ≥ 2 cm (60 patients with the use of UAS and 52 patients without). The stone-free status was verified after 8 weeks of operation.

RESULTS

The average diameter of the renal stones in non-UAS or UAS treated groups was 22.5 mm and 22.6, respectively. None of the groups differed significantly in terms of stone side, stone size, stone position, or Hounsfield unite but there was significant difference (p < 0.001) among two groups as regard pre-operative stenting (cases with UAS had 23.3% pre-operative stenting).

CONCLUSIONS

It is not always necessary to use UAS in conjunction with flexible ureteroscopy and laser lithotripsy to treat renal calculi bigger than or equal two cm. Without the assistance of UAS, the surgery may be carried out successfully and safely.

Impact of pulse duration alterable laser ureterorenoscopic lithotripsy for upper urinary tract calculi

To assess the effectiveness of a pulse duration alterable Holmium-YAG (Ho:YAG) laser on the stone-free rate (SFR) compared to a conventional pulse duration fixed laser after ureterorenoscopic lithotripsy (URSL). The medical records from patients with upper urinary tract calculi of ≥ 9 mm and < 30 mm were retrospectively investigated. URSL using a conventional Ho:YAG Laser (group C) or a pulse duration alterable Ho:YAG system (group A) was included. In total, 228 and 188 patients were enrolled in groups C and A, respectively. A 272 µm optical core bare-ended, reusable laser fiber was used, and the laser system was set to a standard 0.8 J and 10 Hz (8 W of average power) in both groups. URSL adopts active fragmentation using an extraction approach. SF was defined as the complete absence of stone fragments on computed tomography (CT) 1-2 months after URSL. Sex, BMI, stone length, stone volume, stone density, and the number of patients with positive preoperative urine cultures were not significantly different between the groups. However, age, rate of preoperative febrile urinary tract infection (fUTI), and pre-stenting were significantly higher in group A, and the operative times and incidence of postoperative fUTI were comparable. The SFRs were 71.5% and 80.3% in groups C and A, respectively (P = 0.035). Multivariate logistic regression revealed that the use of conventional laser was associated with non-SF (odds ratio [OR] 1.090, 95% confidence interval [CI] 1.01-1.18, P = 0.040). The present study revealed the superior performance of a pulse duration alterable Ho:YAG laser on the SFR after URSL compared to a conventional pulse duration fixed laser delivery system.

External validation of the current scoring systems and derivation of a novel scoring system to predict stone free rates after retrograde intrarenal surgery in patients with cumulative stone diameter of 2-4 cm

OBJECTIVE

Our primary aim is to perform the external validation of the current scoring systems in predicting stone-free status (SFS) after retrograde intrarenal surgery (RIRS) for renal stones 2-4 cm and develop a novel scoring system by re-examining possible predictive factors related to SFS.

METHODS

Patients who underwent RIRS due to renal stones with a cumulative stone diameter of 2-4 cm between January 2017 and March 2021 were retrospectively screened. Residual stones ≤2 mm were defined as clinically insignificant, and these cases were considered to have SFS. Possible predictive factors related to SFS were examined using the multivariate logistic regression analysis. A nomogram and a scoring system were developed using independent predictive variables. The prediction ability of the previous and the new scoring system were evaluated with the ROC analysis.

RESULTS

The existing scoring systems were found to be insufficient in predicting SFS (AUC < 0.660 for all). The independent predictors of SFS were identified as stone surface area (OR: 0.991, p < 0.001), stone density (OR: 0.998, p < 0.001), number of stones (OR: 0.365, p = 0.033), and stone localization (p = 0.037). Using these predictive markers, a new scoring system with a score ranging between 4 and 15 was developed. The AUC value for this scoring system was 0.802 (0.734-0.870).

CONCLUSION

The RUSS, S-ReSC and R.I.R.S. scoring systems and Ito's nomogram failed to predict SFS in stones >2 cm. The SFS predictive ability of our new scoring system was higher in >2 cm stones compared to the other scoring systems.

Ureteroscopy and Holmium:YAG Laser Lithotripsy For Upper Tract Stones in a New Urology Centre: Our Initial Experience

Background

To demonstrate the outcome of our initial experience in the management of upper tract stones with ureteroscopy and Holmium: YAG laser lithotripsy.

Methodology

The data of thirty-two patients who had ureteroscopy and laser lithotripsy for upper urinary tract stones at a private urology centre in Awka, Anambra State Nigeria from September 2020 to June 2022 (20months) were retrospectively studied. Their sociodemographic data, clinical symptoms, the location and size of the stones, preoperative and postoperative stent use, hospital stay, complications, and stone-clearance rates were analyzed.

Results

A total of 32 procedures were performed on 32 patients. The mean age of the patients was 44.7 ± 12.2 years. The mean stone size was 15.4 ± 6.7mm with a range of 8.0-39mm, and Hounsfield unit ranging from 233-906. The stones were on the right tract, left tract, and bilateral in 46.9%, 43.7%, and 9.4% of the cases respectively. The patients had a mean length of hospital stay of 3.31 ± 1.45 days. The stone clearance rate was 90.3%. 53.1% of the patients had postoperative complications with 40.6% of these being post-operative fever which resolved with antibiotics. There was treatment failure in one patient due to the inability to scope the ureter on account of ureteral stricture.

Conclusion

Ureteroscopy and laser lithotripsy are safe and effective options in the management of upper tract stones with the advantages of being performed via a natural orifice, being less painful, with reduced risk of severe bleeding, irreversible loss of renal parenchyma, as well as a short hospital stay.

Flexible Ureteroscopy and Nephroscopy for Stone Removal in Patients with Multiple Renal Calculi

Objective

Renal calculi are a common type of urological calculi and are associated with morbidity. This study was aimed at exploring the effect of flexible ureteroscopy and nephroscopy on stone removal in patients with multiple renal calculi.

Method

This randomized controlled trial included a total of 78 cases with multiple renal calculi in our hospital. The patients were randomly divided into the study and control groups and treated with flexible ureteroscopy and percutaneous nephrolithotomy with pneumatic ballistics, respectively. The surgery condition, levels of prostaglandin F2α (PGF2α), prostaglandin E2 (PGE2), keratocyte growth factor (KGF), renal function indices, and the incidence of complications were analyzed before and after surgery in the two groups.

Result

The operation time, the postoperative analgesia pump application time, one-time stone removal rate, the intraoperative blood loss, and hospital stay of the study group were significantly lower than those of the control group. Postsurgery, the levels of PGE2, PGF2α, and KGF in the study group were significantly lower than those in the control group. The serum levels of SCR, BUN, and NGAL in the study group were significantly lower than those in the control group. In addition, the incidence complications in the study group were significantly lower.

Conclusion

Flexible ureteroscopy and laser lithotripsy under nephroscopy were equally effective against multiple renal calculi. Flexible ureteroscopy reduced surgical trauma without affecting renal function and had a low incidence of complications.

External validation of the T.O.HO. score and derivation of the modified T.O.HO. score for predicting stone-free status after flexible ureteroscopy in ureteral and renal stones

OBJECTIVE

The T.O.HO. scoring system was developed to predict stone-free status after flexible ureterenoscopy (fURS) lithotripsy applied for ureter and renal stones. This study aimed to perform the external validation of the T.O.HO. score in the Turkish population and propose a modification for this system.

MATERIAL METHODS

Patients who underwent fURS for kidney and ureteral stones between January 2017 and January 2020 were retrospectively analysed. The patient and stone characteristics and perioperative findings were noted. The T.O.HO. score was externally validated and compared with the STONE score. Stone-free parameters were evaluated with the multivariate analysis. Based on the results of this analysis, the T.O.HO. score was modified and internally validated.

RESULTS

A total of 621 patients were included in the study. The stone-free rate was determined as 79.8% (496/621) after fURS. The regression analysis showed that stone area had better predictive power than stone diameter (P = .025). Lower pole (reference), middle pole [odds ratio (OR) = 0.492 P = .016] and middle ureteral (OR = 0.227, P = .024) localisations, stone density (OR = 1.001, P < .001), and stone volume (OR = 1.008, P < .001) were determined as independent predictive markers for stone-free status. Based on the effect size of the stone surface area in the nomogram, stone volume was divided into five categories, at 1-point intervals. The AUC values of the T.O.HO., STONE, and modified T.O.HO. score in predicting stone-free status were calculated as 0.758, 0.634, and 0.821, respectively. The modified T.O.HO. created by adding stone volume was statistically significantly superior to the original version (ROC curve comparison, P < .001).

CONCLUSION

The T.O.HO. score effectively predicted stone-free status after fURS. However, modified T.O.HO. SS showed the best predictive performance compared with original T.O.HO. SS.