Real-time simultaneous endoscopic combined intrarenal surgery with intermediate-supine position: Washout mechanism and transport technique

An internally validated prognostic nomogram model predicts the stone-free rate following endoscopic combined intrarenal surgery for renal stones

BACKGROUND

Here, we aim to develop and validate a viable prognostic nomogram model for predicting a stone-free rate of kidney stones patients based on retrospective cohort analysis.

METHODS

This is a retrospective study that obtained a continuous cohort from the databases of two hospitals (General Hospital of Southern Theater Command, and Guangdong Second Provincial General Hospital), including 522 patients with kidney stones who underwent Endoscopic Combined Intrarenal Surgery (ECIRS) from January 2015 to December 2022.The characteristics of the primary cohort between the SF (stone-free) and SR (stone residue) groups were identified using single factor and multivariate logistic regression analyses. Factors in the main cohort were identified using minimal absolute shrinkage and selective operator regression. A nomogram was then constructed using these factors for subsequent analyses. Finally, a calibration curve, a receiver operating characteristic curve (ROC), and a decision curve analysis (DCA) curve were analyzed and plotted, and then used to test the predictive value of the nomogram in both calibration and discrimination.

RESULTS

Hydronephrosis, Renal Infundibular Length (RIL), Renal Infundibular Width (RIW), stone burden, and number of calyces involved were revealed to be significant factors in the prediction of stone-free rate after ECIRS. These five factors were used to develop a nomogram with good calibration and differentiation. The area under the curve (AUC) was 0.811 (95% CI: 0.766-0.856). The DCA demonstrated that the nomogram has clinical utility.

CONCLUSIONS

Hydronephrosis, renal infundibular length, renal infundibular width, stone burden, and number of involved calyces were all significantly linked with residual stone after ECIRS. A nomogram created with these five factors showed good calibration, differentiation, and clinical usefulness.

Endoscopic Combined Intrarenal Surgery: best practices and future perspectives

INTRODUCTION

Endoscopic Combined Intrarenal Surgery (ECIRS) has emerged as a promising technique for the management of large and complex kidney stones, potentially offering advantages over traditional Percutaneous Nephrolithotomy (PCNL). This study aims to evaluate best practices, outcomes, and future perspectives associated with ECIRS.

MATERIALS AND METHODS

A comprehensive PubMed search was conducted from 2008 to 2024, using MESH terms and the following key words: "ECIRS" and "Endoscopic Combined Intrarenal Surgery" The search yielded 157 articles, including retrospective cohort studies, two randomized controlled trials (RCTs), and four meta-analyses comparing ECIRS with PCNL. Most important findings were summarized regarding indications, patient positioning, kidney access, tract size, surgical outcomes, and complications.

RESULTS

ECIRS demonstrated higher stone-free rate, lower complication rate, and a reduced need for multiple procedures compared to traditional PCNL. Additionally, ECIRS has the potential to integrate new technologies to further enhance outcomes.

CONCLUSION

ECIRS demonstrates significant advantages in the management of large kidney stones. Future research should focus on well-designed RCTs to provide robust evidence of its efficacy, safety, and cost-effectiveness, potentially establishing ECIRS as the first option treatment for complex kidney stones.

Development of a novel percutaneous digital flexible nephroscope: its use and application

BACKGROUND

Renal calculi are one of the most frequent diseases in urology, and percutaneous nephrolithotomy (PCNL) being the gold standard for treating renal calculi larger than 2 cm. However, traditional rigid nephroscope cannot bend, presents significant limitations during PCNL. This study aims to develop a novel digital flexible nephroscope for PCNL and verify its safety and efficacy using 3D printed models and ex vivo porcine kidney models, providing new equipment for PCNL.

METHODS

Based on the determined technical parameters, the novel digital flexible nephroscope was manufactured. First, 3D-printed model and ex vivo porcine kidney models were utilized to simulate the PCNL procedures. Then, the traditional rigid nephroscope and the novel digital flexible nephroscope were utilized to simulate the PCNL procedures on 10 ex vivo porcine kidneys for comparison. We observed and recorded the renal calyces visualized and accessed by both the traditional rigid nephroscope and the novel digital flexible nephroscope.

RESULTS

In both the 3D printing and ex vivo porcine kidney models, the novel percutaneous digital flexible nephroscope smoothly entered the renal collecting system through the percutaneous renal tract. It freely changed angles to reach most target calyces, demonstrating significant advantages over the traditional rigid nephroscope.

CONCLUSION

The successful development of the novel percutaneous digital flexible nephroscope allows it to be used either independently or as an adjunct in complex stone cases, providing more effective and safer surgical equipment for percutaneous nephrolithotomy.

Efficacy of mini-endoscopic combined intrarenal surgery for pediatric kidney calculi: a single center retrospective study

Management of large pediatric kidney calculi (PKC) is challenging. This study aimed to evaluate the efficacy and safety of miniature endoscopic combined intrarenal surgery (mini-ECIRS) for PKC. We retrospectively analyzed mini-ECIRS in 16 pediatric patients undergoing kidney stone treatment between November 2014 and October 2023 to determine its safety, efficacy, and associated outcomes. The median age was 50.50 (interquartile range: 36.75, 84.75) months, and the mean stone size was 21.63 ± 11.65 mm. The stone-free rate was 81.25%. The median decrease in hemoglobin level on the day after surgery was 1.10 (0.80, 1.55), and no patient required a blood transfusion. The median number of general anesthesia procedures was 2.00 (2.00, 2.00). Postoperative complications included fever in two patients and difficulty in removing the ureteral stent in one patient. In this cohort, five patients underwent pre-stenting under general anesthesia before mini-ECIRS. Age was significantly lower in the pre-stenting group than in the non-pre-stenting (P < 0.01); however, there were no significant differences in operative time, stone-free rate, total number of general anesthesia procedures, hemoglobin loss, or postoperative hospital stay between the groups. Mini-ECIRS was found to be a safe and efficient treatment method with a high stone removal rate in pediatric patients.

Influence of tract location on the outcomes of endoscopic combined intrarenal surgery: A retrospective analysis of 1000 cases

OBJECTIVES

This study aimed to investigate the influence of tract location on surgical outcomes in endoscopic combined intrarenal surgery (ECIRS), considering the location of residual stones.

METHODS

From January 2015 to December 2021, 1417 consecutive patients underwent ECIRS in three hospitals. After excluding patients with preoperative percutaneous nephrostomy, intended multi-stage procedures, those with a tract in the renal pelvis, and those with multiple tracts, 1000 patients were retrospectively analysed by comparing three groups based on tract location: group 1 (upper calyx), group 2 (middle calyx), and group 3 (lower calyx). A multivariate logistic regression model was implemented to assess whether the tract location independently affected the stone-free status.

RESULTS

Patient characteristics were significantly different among the groups in terms of age, stone laterality, presence of calyceal stones, and hydronephrosis. There were no differences in stone-free rate (SFR) among the three groups. Multivariate analysis indicated that the tract location (group 1 or 2 compared with group 3) did not significantly affect the stone-free status (odds ratio = 1.4, 0.9-1.9, p = 0.066). Surgical duration significantly varied among the groups, with the shortest time observed in group 1. Organ injury was observed exclusively in group 1 (1.13%). Residual fragments were predominantly found in the lower calyx, with the calyx associated with the tract being the second most common location.

CONCLUSIONS

Tract location does not significantly affect SFR. To improve the SFR, observation of the lower calyx and tract placement is important.

Endoscopic combined intrarenal surgery composed of micro-perc and retrograde intrarenal surgery in the treatment of complex kidney stones in children

OBJECTIVE

This research aims to explore the efficiency and safety of endoscopic combined intrarenal surgery (Micro-ECIRS) composed of micro-percutaneous nephrolithotomy (Micro-perc) and retrograde intrarenal surgery (RIRS) in the Galdakao-modified supine Valdivia (GMSV) position for a single session for the treatment of complex nephrolithiasis in children.

MATERIALS AND METHODS

This study retrospectively reviewed patients aged < 18 years who underwent Micro-ECIRS in the GMSV position for renal stones larger than 2 cm under ultrasound guidance between August 2020 to May 2022 at our institution.

RESULTS

A total of 13 patients (8 males and 5 females) received Micro-ECIRS for renal stones under ultrasound guidancewhile adopting the GMSV position. The average stone size was 2.7 cm (range: 2.1-3.7 cm). Among them, 6 patients had left kidney stones, 5 patients had right kidney stones, and 2 patients had bilateral kidney stones. The mean operative time was 70.5 min (range: 54-93 min). The mean hospital stay was 6.4 days (range: 4-9 days). The mean hemoglobin decrease was 8.2 g/L (range: 5.1-12.4 g/L). The total number of kidneys that had complete stone clearance was 8 kidneys at 48 h postoperatively, 11 kidneys at 2 weeks postoperatively, and 14 kidneys at 1 month postoperatively.

CONCLUSION

Our results demonstrate that Micro-ECIRS while patients are in the GMSV position is a safe and effective method for the treatment of complex children nephrolithiasis. However, all children made three hospital visits and received anesthesia three times. Further research is needed to confirm these findings.

Current role of endoscopic combined intrarenal surgery in the management of renal stones: A scoping review

Introduction

This study aims to review the current role of endoscopic combined intrarenal surgery (ECIRS) in the management of renal stones, with a focus on its efficacy and safety. The secondary outcome was to highlight the tips and tricks to improve the urologist's experience with ECIRS.

Methods

A scoping review of the literature, in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines, was performed, using ECIRS and flexible ureteroscopy and percutaneous nephrolithotomy as the search terms. All original articles were screened and included.

Results

Thirty-three studies were included in the analysis. ECIRS showed a good efficacy and safety profile, with an excellent stone-free rate and a low rate of complications, mostly Clavien-Dindo I/II. With ECIRS, a reduction in the need for multiple access tracts was noted and direct visualization of the targeted calyx during the puncture increased the ability to attain transpapillary punctures, thereby reducing the amount of bleeding.

Conclusion

ECIRS, as the first-line minimal access intervention, is safe and efficacious, particularly for achieving a stone-free status in patients with large complex stones in a single stage. The ability to gain access under direct vision and the reduction in the number of tracts, in both the supine and the prone positions, makes this procedure an attractive surgical choice.

Evolution and current applications of endoscopic combined intrarenal surgery: a scoping review from back to the future

PURPOSE OF REVIEW

To systematically review the evolution of techniques, technology, clinical utility, limitations and possible future applications of endoscopic combined intrarenal surgery (ECIRS) for ureteral and kidney stones.

RECENT FINDINGS

The literature search was performed on 18th January 2023 using PubMed, EMBASE and Scopus. 35 studies were included. Among them, six were reviews. Since its introduction in 2008, ECIRS has evolved and improved. ECIRS can be performed in different patient position, such as modified supine Valdivia position by Galdakao, prone position with split-leg and supine position with good outcomes. Instrument miniaturization has also been introduced in ECIRS making it doable in an ambulatory setting. ECIRS showed shorter operative time, lower complication rate, and retreatment compared with conventional PCNL. Operative outcomes of mini-ECIRS are better than mini-PCNL alone. ECIRS also showed good outcomes in impacted upper ureteric stones. Recently, some studies have explored the robotic-assisted kidney puncture in ECIRS that avoided multitrack surgery, especially in anomalous kidney and staghorn stones.

SUMMARY

ECIRS is ready for primetime in endourology and can be considered the next gold-standard for a personalized stone approach in complex kidney stones.

PERCUTANEOUS APPROACH TO THE KIDNEY: SIMILARITIES AND DIFFERENCES OF VARIOUS TECHNIQUES - EXPERIENCE IN OSIJEK UNIVERSITY HOSPITAL CENTER

Today, percutaneous nephrolithotomy (PCNL) is a standard procedure in the treatment of large kidney stones. Development of the procedure began in 1976 with publication of the first reports, while turning point came in 1985 when the first 250 cases were described. Subsequently, PCNL has become standard in the treatment of kidney stones instead of open surgery. Numerous modifications of the procedure have been developed with advancement of modern technology. Nevertheless, there is still the necessity for clearer understanding of differences and circumstances of choice among different techniques. There are significant differences in the instruments used for the procedure, so we distinguish standard PCNL (working channel of 24-30 Fr), mini PCNL (working channel of 11-18 Fr), ultra-mini PCNL (working channel <15 Fr), and micro PCNL (working channel <6 Fr). With the development of flexible ureteroscopy (FURS), a combined method is also being developed, i.e., Endoscopic Combined IntraRenal Surgery (ECIRS, PCNL + FURS). Furthermore, each procedure can be performed in prone or supine position. The aim of this paper is to point out the similarities and differences, the advantages and disadvantages of different techniques, with an additional aim to present our experience and current standard practice in kidney stone treatment.

Miniaturization in percutaneous nephrolithotomy: What is new?

Objective

To summarize recent advancements in mini-percutaneous nephrolithotomy (mini-PCNL) in surgical technique, stone removal strategy, lithotripsy, and surgical model from the current literature.

Methods

We conducted a narrative review of relevant English-language articles up to October 2022 using the PubMed and Web of Science databases. The following keywords were used in the search: "percutaneous nephrolithotomy", "minimally invasive percutaneous nephrolithotomy", "mini-PCNL", "mini-perc", "mPCNL", and "miniaturization".

Results

A series of new progress has been made in many aspects of mini-PCNL, such as further reduction of tract size-needle perc and further improvement of robotic-assisted PCNL-artificial intelligence-powered robotic devices.

Conclusion

Many studies and trials have been conducted to reduce morbidity and increase the safety and effectiveness of mini-PCNL. It is crucial to realize that miniaturization of PCNL requires not only a smaller percutaneous tract size, but also an adjustment strategically in renal access, stone removal, lithotripsy, and surgical model in general. More large-scale prospective research needs to be carried out to further validate and optimize the safety and effectiveness of mini-PCNL.

Endoscopic combined intrarenal surgery in the prone split-leg position versus Galdakao-modified supine Valdivia position for the management of partial staghorn calculi

OBJECTIVE

To evaluate and compare the outcome of ECIRS in the treatment of partial staghorn renal calculi in both prone split-leg positions versus GMSV positions with regard to; technical aspects, success rate, operative time, complications, safety, and effectiveness of both approaches.

PATIENTS AND METHODS

Between October 2018 and August 2021, 66 patients with partial staghorn calculi were enrolled in this prospective comparative study. Patients were randomly divided according to a 1:1 ratio into two groups. Group A included 33 patients who were treated by (ECIRS) in the prone split-leg position, and group B included 33 patients who were treated by (ECIRS) in the Galdakao-modified supine Valdivia (GMSV) position.

RESULTS

No significant statistical difference between both groups regarding the mean age (p = 0.448), mean body mass index (BMI) (p = 0.137), mean stone burden (p = 0.435), mean operative time (p = 0.541) and the number of calyces located in branched stones (p = 0.628). The mean hospital stay was 6.71 ± 1.12 days for group A and 6.66 ± 1.10 days for group B patients (p = 0.724). The final SFR was achieved in (29)87.87% and (30)90.9% of group A & B patients, respectively (p = 0.694). No significant difference was detected between both groups in perioperative complication rates.

CONCLUSION

ECIRS is safe and effective in treating partial staghorn calculi either in the prone split-leg position or in the Galdakao-modified supine Valdivia position, with comparable outcomes and no statistically significant difference between both positions.

The First 100 Cases of Endoscopic Combined Intrarenal Surgery in Korea: Matched Cohort Analyses versus Shock-Wave Lithotripsy

PURPOSE

This study presents our initial experience with endoscopic combined intrarenal surgery (ECIRS) for large renal stones and compares the results of a propensity score-matched cohort of patients undergoing shock-wave lithotripsy (SWL).

MATERIALS AND METHODS

A total of 100 adults underwent ECIRS for renal stones between August 2017 and January 2019. For comparison, 2172 patients who underwent a first session of SWL between January 2005 and May 2018 were included in the SWL cohort. Propensity score matching was performed using maximal stone length (MSL), mean stone density (MSD), and stone heterogeneity index (SHI) scores. Stone-free rate (SFR) and success rate were compared between ECIRS and SWL.

RESULTS

In the ECIRS group, the mean MSL, mean MSD, and mean SHI were 28.7±15.2 mm, 1013.9±360.0 Hounsfield units (HU), 209.4±104.0 HU, respectively. The SFR was 70%, and the success rate was 82.0% in this group. Although the ECIRS group had larger, harder, and more homogeneous stones than the SWL group, ECIRS showed a higher SFR and success rate than SWL. After propensity-score matching, SFR and success rate remained higher with ECIRS than with SWL (both, p<0.001). In multivariate logistic regression, smaller stone size [odds ratio (OR): 0.947, 95% confidence interval (CI): 0.913-0.979, p=0.002] and lower Seoul National University Renal Stone Complexity score (OR: 0.759, 95% CI: 0.610-0.935, p=0.011) were independent predictors of successful ECIRS.

CONCLUSION

ECIRS showed a higher SFR and success rate than SWL for large renal stones. Smaller stone size and lower complexity of stones were associated with a higher likelihood of successful ECIRS.

Endoscopic Combined Intrarenal Surgery Versus Percutaneous Nephrolithotomy for Complex Renal Stones: A Systematic Review and Meta-Analysis

Background: Endoscopic combined intrarenal surgery (ECIRS) adds ureteroscopic vision to percutaneous nephrolithotomy (PCNL), which can be helpful when dealing with complex renal stones. Yet, there is still no consensus on the superiority of ECIRS. We aimed to critically analyze the available evidence of studies comparing efficacy, safety, bleeding risk, and efficiency of ECIRS and PCNL. Methods: We searched for studies comparing efficacy (initial and final stone-free rate), safety (postoperative fever, overall and severe complications), efficiency (operative time and hospital stay) and bleeding risk between ECIRS and PCNL. Meta-analysis was performed. Results: Seven studies (919 patients) were identified. ECIRS provided a significantly higher initial stone-free rate, higher final stone-free rate, lower overall complications, lower severe complications, and lower rate of requiring blood transfusion. There was no difference between the two groups in terms of postoperative fever, hemoglobin drop, operative time, and hospital stay. In the subgroup analysis, both minimally invasive and conventional ECIRS were associated with a higher stone-free rate and lower complication outcomes. Conclusions: When treating complex renal stones, ECIRS has a better stone-free rate, fewer complications, and requires fewer blood transfusions compared with PCNL. Subgroups either with minimally invasive or conventional intervention showed a consistent trend.

Application of a new position in endoscopic combined intrarenal surgery: modified prone split-leg position

Background

Endoscopic combined intrarenal surgery (ECIRS) is well established as a minimally invasive procedure for the treatment of multiple urolithiasis. The position is the key to the perfect combination of percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS). Galdakao-modified supine Valdivia (GMSV) and prone split-leg positions are widely used. However, both positions have their own advantages and disadvantages. This study aimed to evaluate the effect of ECIRS in the treatment of multiple urolithiasis in the modified prone split-leg position.

Patients and methods

A total of 96 patients with multiple urolithiasis underwent ECIRS in modified prone split-leg position from September 2017 to January 2021. Relevant demographic and clinical data were analysed retrospectively. Clinical outcomes, such as the stone free rate, complications and postoperative hospital stay were evaluated. The chi-square test was used to compare categorical variables and Student’s t test was applied for continuous variables of the treatment groups.

Results

The mean renal stone size was 32.5 ± 10.7 mm and renal stone surface area was 712.2 ± 264.8 mm². The mean ureteral stones size was 24.8 ± 12.3 mm. The mean surgical time was 82.2 ± 38.3 min. The incidence of complications was 16.7%, and they were mainly grade 1 and grade 2. No complications occurred above grade 3. The stone was completely removed in 75 (78.1%) patients in a single operation. The risk factors affecting the stone-free rate of ECIRS were analysed, and only the number of involved calyces by stone was found to be significant (p = 0.01).

Conclusion

ECIRS is safe and effective in the treatment of multiple renal calculi or multiple renal calculi with ipsilateral ureteral calculi in the modified prone split-leg position. The modification of the prone split-leg position makes the retrograde operation more convenient, which is conducive to the combination of RIRS and PCNL.

Comparison of the safety and efficacy between the prone split-leg and Galdakao-modified supine Valdivia positions during endoscopic combined intrarenal surgery: A multi-institutional analysis

OBJECTIVES

To evaluate the safety and efficacy of the prone split-leg and the Galdakao-modified supine Valdivia positions during endoscopic combined intrarenal surgery.

METHODS

A multi-institutional, retrospective cohort study was conducted between January 2014 and December 2018. The stone-free and complication rates were compared between the prone split-leg and the Galdakao-modified supine Valdivia positions. Anatomical variations were evaluated using contrast-enhanced computed tomography imaging.

RESULTS

In total, 118 and 100 patients underwent endoscopic combined intrarenal surgery in the prone split-leg and Galdakao-modified supine Valdivia positions, respectively. Renal punctures in the prone split-leg position were predominantly executed through the lower calyces (78.0%), whereas those in the Galdakao-modified supine Valdivia position were primarily performed through the middle calyces (64.0%; P < 0.001). Surgical duration in the prone split-leg position was significantly shorter than that in the Galdakao-modified supine Valdivia position (106.5 vs 126.0 min; P = 0.0459). There were no significant differences in the stone-free rate between the two positions (78.8% vs 76.0%; P = 0.629). Incidences of urinary tract injury (P = 0.033) and febrile urinary tract infection (23.7% vs 10.0%; P = 0.011) in the prone split-leg position were significantly higher than that in the Galdakao-modified supine Valdivia position. The tilt of the major renal axis was significantly greater in the prone position than the corresponding values in the oblique position (19.4° vs 8.5°; P = 0.019).

CONCLUSIONS

Anatomical variation might result in the differences of renal puncture calyx. Endoscopic combined intrarenal surgery in the Galdakao-modified supine Valdivia position may bring equal stone-free status, with a longer surgical time but fewer complications including febrile urinary tract infection and urinary tract injury than the prone split-leg position.

Effectiveness of Percutaneous Nephrolithotomy, Retrograde Intrarenal Surgery, and Extracorporeal Shock Wave Lithotripsy for Treatment of Renal Stones: A Systematic Review and Meta-Analysis

Background and objectives: To perform a updated systematic review and meta-analysis comparing effectiveness of percutaneous nephrolithotomy (PCNL), retrograde intrarenal surgery (RIRS), and extracorporeal shock wave lithotripsy (ESWL) for treatment of renal stones (RS). Materials and Methods: A total of 37 studies were included in this systematic review and meta-analysis about effectiveness to treat RS. Endpoints were stone-free rates (SFR), incidence of auxiliary procedure, retreatment, and complications. We also conducted a sub-analysis of ≥2 cm stones. Results: First, PCNL had the highest SFR than others regardless of stone sizes and RIRS showed a higher SFR than ESWL in <2 cm stones. Second, auxiliary procedures were higher in ESWL than others, and it did not differ between PCNL and RIRS. Finally, in <2 cm stones, the retreatment rate of ESWL was higher than others. RIRS required significantly more retreatment procedures than PCNL in ≥2 cm stones. Complication was higher in PCNL than others, but there was no statistically significant difference in complications between RIRS and PCNL in ≥2 cm stones. For ≥2 cm stones, PCNL had the highest SFR, and auxiliary procedures and retreatment rates were significantly lower than others. Conclusions: We suggest that PCNL is a safe and effective treatment, especially for large RS.

Effectiveness of Percutaneous Nephrolithotomy, Retrograde Intrarenal Surgery, and Extracorporeal Shock Wave Lithotripsy for Treatment of Renal Stones: A Systematic Review and Meta-Analysis

Background and objectives: To perform a updated systematic review and meta-analysis comparing effectiveness of percutaneous nephrolithotomy (PCNL), retrograde intrarenal surgery (RIRS), and extracorporeal shock wave lithotripsy (ESWL) for treatment of renal stones (RS). Materials and Methods: A total of 37 studies were included in this systematic review and meta-analysis about effectiveness to treat RS. Endpoints were stone-free rates (SFR), incidence of auxiliary procedure, retreatment, and complications. We also conducted a sub-analysis of ≥2 cm stones. Results: First, PCNL had the highest SFR than others regardless of stone sizes and RIRS showed a higher SFR than ESWL in <2 cm stones. Second, auxiliary procedures were higher in ESWL than others, and it did not differ between PCNL and RIRS. Finally, in <2 cm stones, the retreatment rate of ESWL was higher than others. RIRS required significantly more retreatment procedures than PCNL in ≥2 cm stones. Complication was higher in PCNL than others, but there was no statistically significant difference in complications between RIRS and PCNL in ≥2 cm stones. For ≥2 cm stones, PCNL had the highest SFR, and auxiliary procedures and retreatment rates were significantly lower than others. Conclusions: We suggest that PCNL is a safe and effective treatment, especially for large RS.

Surgical management of urinary stone

Urolithiasis is a common urological disease that causes a significant deterioration in patients’ life quality due to severe pain and frequent recurrence. With increases in the incidence of urolithiasis, different treatment methods have been developed. Although urolithiasis is still managed in Korea with extracorporeal shock wave lithotripsy, the development of minimally invasive techniques and endoscopy instruments has led to increased surgery. Prior to the introduction of endoscopy, urolithiasis surgery was performed as open procedures such as ureterolithotomy, pyelolithotomy, and nephrolithotomy. However, most recent stone surgeries are performed using endoscopy with comparable outcomes and fewer complications. Laparoscopic or robot-assisted laparoscopic surgeries are performed in exceptional cases. Since urolithiasis can be found in various urinary organs, such as the kidney, ureter, bladder, and even the urethra, the approach, method, and availability of endoscopy will vary depending on the stoneʼs size and location. Understanding the types and characteristics of each surgical method will determine the appropriate procedure for each patient and improve the surgical outcomes.

Endoscopic combined intrarenal surgery (ECIRS) - Tips and tricks to improve outcomes: A systematic review

OBJECTIVE

This study aimed at assessing current efficacy and safety of endoscopic combined intrarenal surgery (ECIRS) for the treatment of large and/or complex urolithiasis and identifying relevant tips and tricks able to improve its outcomes, mainly deriving from the adjunct of retrograde flexible ureteroscopy to the traditional antegrade approach of percutaneous nephrolithotomy (PNL).

MATERIAL AND METHODS

A systematic review was conducted using relevant databases (Ovid Medline, PubMed, Scopus, and Web of Sciences), employing "ECIRS" as the search term in all cases, and then adding "endoscopic combined intrarenal surgery" and "flexible ureteroscopy AND percutaneous nephrolithotomy" as search terms for PubMed and Scopus. Original articles and systematic reviews were selected according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Additionally, the reference lists of the selected publications were checked manually.

RESULTS

A total of 14 studies were selected for analysis: two systematic reviews, one randomized controlled trial, five nonrandomized comparative studies, three prospective case series, and three retrospective case series. ECIRS achieves high stone-free rates and rather low/low Clavien-Dindo grade complication rates, confirming the role of retrograde ureteroscopy in the maximization of its efficacy and safety. A narrative synthesis of the most recognized tips and tricks of ECIRS is provided.

CONCLUSION

The contribution of retrograde flexible ureteroscopy during PNL is essential. It plays a dual role, both diagnostic and active, allowing tailoring of the procedure to the patient, urolithiasis, and anatomy of the collecting system and optimization of the PNL efficacy and safety. This is ECIRS: an updated, complete, and versatile version of PNL.

Comparison of stone-free rates following shock wave lithotripsy, percutaneous nephrolithotomy, and retrograde intrarenal surgery for treatment of renal stones: A systematic review and network meta-analysis

OBJECTIVES

To perform a systematic review and network meta-analysis comparing stone-free rates following retrograde intrarenal surgery (RIRS), extracorporeal shock wave lithotripsy (SWL), and percutaneous nephrolithotomy (PCNL) treatments of renal stones.

MATERIALS AND METHODS

Clinical trials comparing RIRS, SWL, and PCNL for treatment of renal stones were identified from electronic databases. Stone-free rates for the procedures were compared by qualitative and quantitative syntheses (meta-analyses). Outcome variables are shown as risk ratios (ORs) with 95% credible intervals (CIs).

RESULTS

A total of 35 studies were included in this network meta-analysis of success and stone-free rates following three different treatments of renal stones. Six studies compared PCNL versus SWL, ten studies compared PCNL versus RIRS, fourteen studies compared RIRS versus SWL, and five studies compared PCNL, SWL, and RIRS. The quality scores within subscales were relatively low-risk. Network meta-analyses indicated that stone-free rates of RIRS (OR 0.38; 95% CI 0.22-0.64) and SWL (OR 0.12; 95% CI 0.067-0.19) were lower than that of PCNL. In addition, stone-free rate of SWL was lower than that of RIRS (OR 0.31; 95% CI 0.20-0.47). Stone free rate of PCNL was also superior to RIRS in subgroup analyses including ≥ 2 cm stone (OR 4.680; 95% CI 2.873-8.106), lower pole stone (OR 1.984; 95% CI 1.043-2.849), and randomized studies (OR 2.219; 95% CI 1.348-4.009). In rank-probability test, PCNL was ranked as No. 1 and SWL was ranked as No. 3.

CONCLUSIONS

PCNL showed the highest success and stone-free rate in the surgical treatment of renal stones. In contrast, SWL had the lowest success and stone-free rate.

Predictors of Uric Acid Stones: Mean Stone Density, Stone Heterogeneity Index, and Variation Coefficient of Stone Density by Single-Energy Non-Contrast Computed Tomography and Urinary pH

We analyzed the capacities of pertinent parameters (determined by single-energy non-contrast computed tomography [NCCT]) and urinary pH to predict uric acid stones. We reviewed the medical records of 501 patients whose stones were removed surgically or passed spontaneously between December 2014 and April 2016. Qualifying participants (n = 420) were stratified by the nature of the stone (calcium oxalate, uric acid, or infectious). Based on NCCT, we determined maximal stone length (MSL), mean stone density (MSD), and stone heterogeneity index (SHI) using Hounsfield units (HU) and calculated the variant coefficient of stone density (VCSD = SHI/MSD × 100). Urinary pH was also ascertained. Mean patient age was 55.55 ± 15.46 years. MSD (448.59 ± 173.21 HU), SHI (100.81 ± 77.37 HU), and VCSD (22.58 ± 10.55) proved to be significantly lower in uric acid versus other types of stones, as did urinary pH (5.33 ± 0.56; all p < 0.001). Receiver operating characteristic (ROC) curves depicting predictability of uric acid stones yielded area under ROC curve (AUC) values for MSD, SHI, VCSD, and urinary pH of 0.806 (95% CI: 0.761⁻0.850), 0.893 (95% CI: 0.855⁻0.931), 0.782 (95% CI: 0.726⁻0.839), and 0.797 (95% CI: 0.749⁻0.846), respectively, with corresponding cutpoints of 572.3 HU, 140.4 HU, 25.79, and 6.0. Among these four parameters, SHI was verifiably (DeLong's test) the most effective predictor of uric acid stones (all p < 0.001). Compared with MSD, VCSD, and urinary pH, SHI may better predict uric acid stones, using a cutpoint of 140.4 HU.