Comparative analysis of retrograde intrarenal surgery and modified ultra-mini percutaneous nephrolithotomy in management of lower pole renal stones (1.5-3.5 cm)

Comparative Analysis of Super-Mini Percutaneous Nephrolithotomy and Retrograde Intrarenal Surgery for the Management of Renal Calculi ≤2 cm Among Somali Population

Background: Limited data have explored the efficacy of super-mini percutaneous nephrolithotomy (SMP) and retrograde intrarenal surgery (RIRS) in managing ≤2 cm renal calculi. This study aims to comprehensively evaluate the safety and effectiveness of SMP compared with RIRS. Methods: This prospective cohort study investigated 210 patients with renal calculi (≤2 cm) undergoing SMP or RIRS, randomly recruited over 4 years. In total, 51.4% underwent SMP and 48.6% underwent RIRS. Results: The mean patient age was 31.3 ± 14.7 years; 56.7% were men, mean stone size of 1.3 ± 0.28 cm, and stone hardness of 1190.1 ± 352.83 Hounsfield units. Pearson's correlation indicated negative correlations for SMP with hospital stays (r = -0.138, p = 0.046), operating time (r = -0.519, p < 0.001), and stone-free rate (SFR) (r = -0.161, p = 0.020); and a positive correlation with a postoperative ureteral catheter (r = +0.389, p < 0.001). With regard to RIRS, the study shows a positive correlation with hospital stay (r = +0.138, p = 0.046), operating time (r = +0.519, p < 0.001), and SFR (r = +0.161, p = 0.020); and a negative correlation with postoperative ureteral catheter (r = -0.389, p < 0.001). Logistic regression, using SMP as the reference, RIRS was associated with β = +0.31, and 1.20 (95% confidence interval [CI], 1.14-1.27, p ≤ 0.001) risk of operation duration and β = +0.37, 1.44 (95% CI, 1.00-2.07, p = 0.047) risk of longer hospital stay. Conclusion: This study investigates the suitability of SMP and RIRS for treating renal calculi ≤2 cm. SMP demonstrated superior efficacy with significantly shorter operating times and reduced hospital stays, suggesting potential advantages for managing lower volume renal stones.

[The 1-cm lower calyx calculus: SWT, URS or Mini-PCNL? Guidelines vs. reality.]

Urinary stones of the upper urinary tract can be considered a widespread public health concern due to their high incidence and prevalence and their health policy-related and financial implications. A significant proportion of newly diagnosed kidney stones are lower-pole stones, i.e., stones affecting the lower calyx group of the renal pelvicalyceal system. These are often diagnosed by chance, i.e., as incidental findings during ultrasound or CT scans performed for other reasons, or as "secondary stones" detected during the diagnostic work-up of symptomatic urinary stones in other locations. Residual disintegrates after extracorporeal shock-wave lithotripsy (ESWL) or endoscopic stone therapy constitute a further, quantitatively significant group. These incidentally discovered lower-pole stones are often characterised by their small size and lack of symptoms. It stands to reason that some of these small, asymptomatic lower-pole stones do not always remain small and asymptomatic, and that treatment tends to become more complex with increasing size. There has been an astonishing lack of published studies with a high level of evidence over the last 20 years to provide a conclusive and reproducible answer to the question posed in this review. Small, asymptomatic stones can be monitored. Symptomatic and rapidly growing stones should be treated. There is a lack of valid risk factors allowing an identification of subgroups that should be treated prophylactically at the asymptomatic stage. In active therapy, a 10-to-20-year-old principle still holds true today: a high stone-free rate in one therapy session is offset by an increased complication rate, with increasing miniaturisation in endourology (retrograde and percutaneous) and increasingly effective laser disintegration shifting this basic principle more and more in favour of flexible URS and (mini, micro) PCNL. The range of indications for ESWL is undoubtedly becoming smaller, and this also applies to lower-pole stones. The results of an ongoing prospective randomised study comparing the different treatment modalities, albeit with recruitment difficulties, are still pending.

Does displacement of lower pole stones during retrograde intrarenal surgery improves stone-free status? A systematic review and meta-analysis

PURPOSE

Kidney stones are one of the most common urological diseases worldwide. The size and location of the stone are the most important factors in determining the most suitable treatment options. The aim of this review was to evaluate the displacement of lower pole stones.

METHODS

Three studies assessing the efficacy of translocating kidney stones from the lower pole of the kidney to other locations during retrograde intrarenal surgery published in the last 20 years were included. A systematic search was conducted in the PubMed, Embase, Latin American and Caribbean Health Sciences Literature (LILACS), and Web of Science databases using the following search terms: "Lower pole," "Lithotripsy." Meta-analysis was performed using Review Manager version 5.4.

RESULTS

Stone-free rates were improved through displacement (odds ratio - OR = -0.15; 95% confidence interval-95%CI -0.24--0.05; p = 0.002; I2 = 21%), but at the cost of increased surgical duration (mean difference = -12.50; 95%CI -24.06--0.95; p = 0.03; I2 = 94%). Although this represents a potentially negative outcome, the improvement in clearance rates justifies the additional investment of time and effort.

CONCLUSIONS

Displacement of lower pole kidney stones for subsequent lithotripsy brings significant benefits in terms of stone-free rate, with no difference in laser energy usage. However, it results in increased surgical time. Despite these factors, the benefits to patients undergoing the procedure are substantial.

Flexible ureteroscopy for lower pole calculus: is it still a challenge?

PURPOSE

Flexible ureteroscopy (fURS) is steadily gaining popularity in the management of renal calculi, including those located in the lower pole (LP). Due to difficulty in accessing to the LP of kidney in minority of cases with fURS and reports of lower stone-free rate (SFR), it is still considered as a challenge in selected cases. The purpose of the review was to analyze the various aspects of fURS for LP stones.

METHODS

An extensive review of the recent literature was done including different factors such as anatomy, preoperative stenting, stone size, flexible scopes, types of lasers, laser fibers, suction, relocation, stone-free rates, and complications.

RESULTS

The significance of various lower pole anatomical measurements remain a subject of debate and requires standardization. Recent improvements in fURS such as single-use digital scopes with better vision and flexibility, high power laser, thulium fiber laser, smaller laser fiber, and accessories have significantly contributed to make flexible ureteroscopy  more effective and safer in the management of LP stone. The utilization of thulium fiber lasers in conjunction with various suction devices is being recognized and can significantly improve SFR.

CONCLUSIONS

With the significant advancement of various aspects of fURS, this treatment modality has shown remarkable efficacy and gaining widespread acceptance in management of LP kidney stones. These developments have made the fURS of LP stones less challenging.

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.

Treatment of 2-4 cm kidney stones: multicentre experience. Comparison of safety, efficacy, and costs of percutaneous nephrolithotomy and retrograde intrarenal surgery

Introduction

The objective of this study is to compare the safety and efficacy, through the stone-free rate (SFR), as well as the costs, between retrograde intrarenal surgery (RIRS) and percutaneous nephrolithotomy (PCNL), for 2-4 cm kidney stones.

Material and methods

We analysed the data relating to RIRS and PCNL performed in 3 reference centres for kidney stones, in the period between 1/2019 and 12/2021. The total number of procedures was 130 (63 RIRS and 67 PCNL). We defined SFR as the absence of lithiasic fragments or stones <3 mm. Results were compared between 2 groups depending on the stone size: 2-3 cm stones (group 1) and >3 cm stones (group 2).

Results

The duration of RIRS was 90 minutes for group 1 and 115 minutes for group 2, and for PCNL it was 135 minutes for group 1 and 145 minutes for group 2. RIRS had shorter duration with a significant difference in group 1 (p = 0.000014). SFR for RIRS was 78% for group 1 and 21% for group 2, and for PCNL it was 92% for group 1 and 81% for group 2. Therefore, there is a statistically significant difference, which is more evident for 3 cm and multiple stones (p = 0.0057 for group 1, p = 0.000146 for group 2). The difference in costs was estimated by calculating the expected costs for a single surgical procedure and the estimated cost per day for ordinary hospitalization.

Conclusions

2-4 cm stones can be safely treated with both RIRS and PCNL, but RIRS should not be chosen as an option for stones >3 cm, except in selected cases. PCNL remains the gold standard for the treatment of complex stones, especially for stones >3 cm. Risk of postoperative complications is higher in PCNL, even if this difference is not great. The costs associated with RIRS, even when recalculating with the need for new treatments, remain cheaper.

Comparison of flexible ureteroscopy and mini-percutaneous nephrolithotomy in the treatment for renal calculi larger than 2 cm: a matched-pair analysis

To compare the effectiveness and safety of flexible ureteroscopy and mini-percutaneous nephrolithotomy for renal calculi > 2 cm and perform subgroup analysis of stone length and age. Patients received mini-percutaneous nephrolithotomy or flexible ureteroscopy in Qilu Hospital of Shandong University from 2016.01 to 2021.03 with renal calculi > 2 cm were retrospectively analyzed. Propensity score matching was performed to get comparable patients. The postoperative hospital days, operation time, complication rate, and stone free rate were compared. The age and stone length were analyzed by subgroup. 162 in 313 patients were finally included. Each group had 81 cases. Outcomes such as intraoperative transfusion, stone free rate show no difference either. Flexible ureteroscopy had shorter postoperative hospital days (3.2 days vs 7.2 days, P < 0.001) and fewer complications (9, 11.1% vs 25, 30.9%, P = 0.002) compared to mini-percutaneous nephrolithotomy. The postoperative hospital days, and complication of the flexible ureteroscopy were significantly lower than those in the mini-percutaneous nephrolithotomy for renal stones ≤ 2.5 cm; when the stone length > 2.5 cm, the stone free rate of flexible ureteroscopy was lower than that of the mini-percutaneous nephrolithotomy group, but not statistically significant. The complications of flexible ureteroscopy in the young group (18-39 years old) were significantly lower than those in the mini-percutaneous nephrolithotomy group. For 2-2.5 cm renal stones, flexible ureteroscopy can achieve a similar stone free rate with shorter hospital stay, and lower complications. For larger stones, flexible ureteroscopy performed poorly. Flexible ureteroscopy may be a better option for younger patients with fewer complications.

Initial Safety and Feasibility of Steerable Ureteroscopic Renal Evacuation (SURE), A Novel Approach for the Treatment of Urolithiasis

Background:

There is a need to reliably render urolithiasis patients completely stone free with minimal morbidity. We report on the initial safety and feasibility with steerable ureteroscopic renal evacuation (SURE) in a prospective study using basket extraction as a comparison.

Materials and Methods:

A pilot randomized controlled study was conducted comparing SURE with basket extraction postlaser lithotripsy. SURE is performed using the CVAC™ Aspiration System, a steerable catheter (with introducer). The safety and feasibility of steering CVAC throughout the collecting system under fluoroscopy and aspirating stone fragments as it was designed to do were evaluated. Fluoroscopy time, change in hemoglobin, adverse events through 30 days, total and proportion of stone volume removed at 1 day, intraoperative stone removal rate, and stone-free rate (SFR) at 30 days through CT were compared.

Results:

Seventeen patients were treated (n = 9 SURE, n = 8 Basket). Baseline demographics and stone parameters were not significantly different between groups. One adverse event occurred in each group (self-limiting ileus for SURE and urinary tract infection for Basket). No mucosal injury and no contrast extravasation were observed in either group. The CVAC catheter was steered throughout the collecting system and aspirated fragments. There was no significant difference in fluoroscopy time, procedure time, change in hemoglobin, or stone removal rate between groups. SURE removed more and a greater proportion of stone volume at day 1 vs baskets (202 mm³vs 91 mm³, p < 0.01 and 84% vs 56%, p = 0.022). SURE achieved 100% SFR at 30 days vs 75% for baskets, although this difference was not statistically significant (p = 0.20).

Conclusions:

This initial study suggests SURE is safe, feasible, and may be more effective in stone removal postlaser lithotripsy compared to basketing. More development is needed, and larger clinical studies are underway.

Comparison of Ultra-Mini Percutaneous Nephrolithotomy and Retrograde Intrarenal Surgery for Renal Stones: A Systematic Review and Meta-Analysis from the KSER Update Series

Miniaturized percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS) for renal stones have been developed to overcome the invasive disadvantages of PCNL. We aimed to compare the therapeutic effect and safety of ultra-mini percutaneous nephrolithotomy (UMPCNL) and RIRS for renal stones using an updated systematic review and meta-analysis. We searched clinical trials comparing UMPCNL and RIRS for renal stones using the PubMed, EMBASE, Cochrane Library, and Google Scholar databases up to October 2021. Seven studies were included in the current study. The renal stone size was 10–20 mm in three studies, 10–25 mm in one study, 10–35 mm in two studies, and not specified in one study. The stone-free rate of UMPCNL was higher than that of RIRS (p = 0.02; odds ratio (OR) = 2.01; 95% confidence interval (CI) = 1.12, 3.61). The complication rate showed no significant difference between UMPCNL and RIRS (p = 0.48; OR = 1.20; 95% CI = 0.73, 1.98). Regarding the operative time, UMPCNL was shorter than RIRS (p = 0.005; weighted mean difference (WMD) = −15.63; 95% CI = −26.60, −4.67). The hospital stay of UMPCNL was longer than that of RIRS (p = 0.0004; WMD = 1.48; 95% CI = 0.66, 2.31). UMPCNL showed higher efficacy than RIRS and similar safety to RIRS. UMPCNL may be a useful therapeutic option for moderate-sized renal stones.

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.

Can mini PCNL achieve the same results as RIRS? The initial single center experience

BACKGROUND

Urolithiasis is a prevalent disease worldwide with high recurrence rate, minimally invasive interventions have largely replaced open ones, namely PCNL and RIRS. Miniaturization, optical improvements, and modern laser types made these procedures safe and effective in the management of single renal stones.Aim of the study: Is to compare the effectiveness of mini PCNL with RIRS in the treatment of single renal stone of ≤25 mm.

PATIENTS AND METHODS

This prospective study that included 60 patients with single renal stones of ≤25 mm and were treated by either mini PCNL (group A) or RIRS (group B). The study was performed during the period from October 2020 to April 2021.

RESULTS

The mean operative time RIRS group was 43.6 ± 10.493, while for miniPCNL it was 36.6 ± 7.035 (P = 0.004). The stone free rate in RIRS and miniPCNL group was 70% and 90% respectively (P = 0.053). The need for JJ stent was higher in RIRS compared to miniPCNL group (70% vs. 40%) respectively (P = 0.02). The duration of hospital stay in miniPCNL was 38.2 h compared to 16.7 h for RIRS group (p = 0.0001). The rate of postoperative hemoglobin drop was higher in MiniPCNL compared to RIRS (P = 0.0001). There was no significant difference regarding complication rates between both groups.

CONCLUSION

Mini-PCNL FOR the treatment of renal stones sized ≤25 mm has high stone free rate, shorter operative time, less requirement for JJ stent and near similar post-operative pain and complications compared to RIRS.

Is physical therapy effective following extracorporeal shockwave lithotripsy and retrograde intrarenal surgery: a meta-analysis and systematic review

Background

Physical therapy, including percussion, inversion, vibration and combinations, was clinically performed to improve the stone free rate (SFR) following lithotripsy procedures. However, physical therapy is not widely accepted in clinical practice owing to lack of high level evidence support and a standard protocol. The present meta-analysis aimed to evaluate the efficacy and safety of physical therapy in improving SFR following extracorporeal shockwave lithotripsy (ESWL) and retrograde intrarenal surgery (RIRS).

Methods

Systematic review of literature from PubMed, Scopus, Cochrane library and Embase was performed in March 2019. The efficacy and safety of physical therapy after ESWL and RIRS were assessed by meta-analysis of SFR and complication rate.

Results

A total of 8 prospective studies with 1065 patients were enrolled. When compared to non-intervention, physical therapy provided a higher SFR (OR:3.38, 95% CI: 2.45–4.66, p < 0.0001) at all time points (week 1, week 2 and month 1), while there was no significant difference in complications such as hematuria, lumbago, dizziness and urinary tract infection (OR: 0.84; 95%CI: 0.62–1.13; p = 0.237). In subgroup analysis of different stone locations, lower calyx stone (OR: 3.51; 95%CI: 2.21–5.55; p < 0.0001), upper ureter and renal pelvic stones (OR:2.79; 95%CI:1.62–4.81; p = 0.0002) had a higher SFR after physical therapy, while there was no significant improvement in SFR in upper and middle calyx stones. In subgroup analysis of different techniques, EPVL (external physical vibration lithecbole, OR:3.47; 95%CI:2.24–5.37; p < 0.0001) and PDI (percussion, diuresis and inversion, OR:3.24; 95%CI:2.01–5.21; p < 0.0001) were both effective in improving SFR when compared to non-intervention.

Conclusions

Physical therapy is effective in improving the SFR after ESWL and RIRS, especially for lower calyx stones, upper ureter and renal pelvic stones, while without significant side effects. External physical vibration lithecbole (EPVL) might provide a relative uniformed and repeatable protocol for clinical practice of physical therapy.

Trial registration

PROSPERO 2019 CRD42019130228.