Percutaneous nephrolithotomy versus retrograde intrarenal surgery: a systematic review and meta-analysis

Investigation of Predictors of Systemic Inflammatory Response Syndrome After Endourological Procedure of Upper Urinary Tract Stones

Background: In order to prevent infectious complications following endourological procedure of upper urinary tract stones, it is essential to determine which patients are at high risk of developing this complication. We aimed to identify predictors that may cause systemic inflammatory response syndrome (SIRS) after the endourological procedure of upper urinary tract stones. Materials and Methods: Patients who underwent percutaneous nephrolithotomy (PNL), flexible ureteroscopy (F-URS), or semirigid ureteroscopy (SR-URS) in our center between January 2011 and June 2020 were evaluated retrospectively. After surgery, patients were pursued for SIRS criteria. Logistic regression analyses were applied to identify predictors of SIRS. Results: A total of 1471 patients were included in the study. The rates of SIRS after PNL, F-URS, and SR-URS were 12.9%, 6.3%, and 1.7%, respectively. In multivariate analysis, predictors for SIRS were determined to be stone volume, operative time, and history of recurrent urinary tract infection (UTI) in the PNL group; ipsilateral stone surgery history, stone volume, and operative time in the F-URS group; and stone volume, operative time, and history of recurrent UTI in the SR-URS group. Conclusion: Stone volume and operative time were determined to be independent predictors of SIRS in endourological surgery of upper urinary tract stones.

Assessment of Factors Responsible for Stone-Free Status After Retrograde Intrarenal Surgery

Aim The study aimed to evaluate the predictive factors that determined stone-free rate (SFR) after retrograde intrarenal surgery (RIRS). Materials and methods This prospective study was conducted on 183 patients undergoing RIRS for renal stones. Patients were categorized into two groups, depending on stone-free status one month following the procedure. SFR was defined as the complete absence of stones or stones <4 mm. The parameters studied included patient demographics, presence of hydronephrosis, presence of preoperative double J-stent, abnormal renal anatomy, and stone characteristics (stone burden, stone number, stone density, stone location, lower pole infundibulopelvic angle, and lower pole renal infundibular length (RIL)). Univariate and multivariate analyses were performed to identify risk factors for residual stones. We assessed the predictive ability of the RIRS score and Resorlu-Unsal stone score (RUSS) for evaluating SFR utilizing receiver operating characteristic (ROC) analysis. Results 183 patients were included in the study with a median age of 51 years. 131 (71.6%) patients were declared stone-free after the procedure. The mean stone size and density were 16.9 SD±7.5 mm and 1038 SD±342 Hounsfield units (HU) respectively. Stone-free patients had lower stone size (14.3 mm vs. 23.6 mm, p<0.01) and stone density (970 HU vs. 1211 HU, p<0.01) compared to non-stone-free patients. Patients with residual stones had steeper lower pole renal infundibulopelvic angle (RIPA) (31.3° vs. 40.7°, p<0.01) and longer RIL (26.6 mm vs. 21.1 mm, p<0.01). Stone multiplicity (p<0.01), lower pole stone location (p<0.01), and renal malformations (p<0.01) were significant influencing factors for residual renal stones after RIRS. Multivariate analysis revealed stone size, stone density (HU), and stone location as independent predictors for SFR after RIRS. Among the scoring systems, the RIRS score had the highest diagnostic accuracy for SFR (area under the curve (AUC): -0.882, 95% CI-0.828-0.936). Conclusion Stone size, stone density (HU), and stone number are important predictors of SFR after RIRS. Lower pole stone location and abnormal renal anatomy play a substantial role in determining SFR after RIRS. In lower pole stones, a long RIL and acute RIPA negatively influence SFR. Additionally, the RIRS score was found to be a better predictor for SFR than the RUSS score.

Three-dimensional printing the navigation template for precise percutaneous renal puncture to treat pyonephrosis on a porcine model and a patient ：a case report

Objective

Percutaneous nephrolithotomy (PCNL) is the main method for pyonephrosis or lithotripsy in urology. However, it often comes with high risk, as the inaccurate puncture inevitably causes bleeding, intra- and post-operative complications. So, a new inter-disciplinary approach is needed to perform the puncture more accurately.

Methods

3 signs made of lead were marked onto the skin of the posterior side of the waist of a domestic pig or a patient, which was scanned by computed tomography (CT). Based on the CT images, the computer design and the 3D printing, a navigation template made of the transparent resin material is constructed. They were attached onto the surgical area on pig or patient according to the signs. During the PCNL, with this template, the puncture position, angle and depth were optimized in order to precisely enter the targeted renal pelvis or calices.

Results

With the 3D navigation templates, 18G puncture needles were used to enter the renal pelvis upon performing the PCNL on a porcine model and a patient. On the porcine model, the urine outflow was observed with minimal complication. Post-operative CT scans revealed that the needle was located in the renal pelvis. For the patient case, the puncture point was designed to target the calix with stone. No obvious bleeding and complication was found in renal puncture with template.

Conclusions

The navigation template was made with the combination of 3D printing, CT images and computer design. This template allows for accurate puncture of the renal pelvis or calix. Surgical improvement in kidney stones and pyonephrosis was observed in porcine model and patient case. In the future, prospective, trandomized, controlled clinical trials are needed to further confirm its advantage.

First 100 Reported Cases of Supine Percutaneous Nephrolithotomy in Malaysia: An Alternative Effective and Safe Approach to Treat Renal Stones

Background

Supine percutaneous nephrolithotomy (s-PCNL) offers great benefits from urological and anaesthetic points of view. We present the first evaluation of the outcomes of s-PCNL in Malaysia. Our aim was to explore the safety and efficacy of s-PCNL.

Methods

Institutional review board approval was obtained from the National Medical Research Register (NMRR ID-21002225-WLP). We retrospectively reviewed 115 patients with renal pelvis stones who underwent single renal access during s-PCNL between November 2020 and May 2023. Patients who underwent simultaneous ipsilateral or contralateral endourological procedures were included. The data were analysed to determine stone-free rates (SFR), major complication rates, blood transfusion rates, operative times and lengths of hospital stay (LOS).

Results

The SFR was higher for the single middle calyceal renal access (MCA) group than for the lower calyceal renal access (LCA) or upper calyceal renal access (UCA) groups (OR: 1.76; 95% confidence interval [CI]: 0.63, 4.92). In total, 0, 1 and 2 patients had major complications in the UCA, MCA and LCA groups, respectively (P = 0.453). One of the 115 patients (0.9%) needed blood transfusion. Subgroup analysis revealed mean operative times of 76.3 min and 78.6 min for patients who underwent sole s-PCNL (PCNL-only group) and those who had simultaneous ipsilateral and contralateral endourological procedures (PCNL-plus group), respectively (P = 0.786). The overall mean LOS was 2.9 days.

Conclusion

s-PCNL is a safe and effective alternative treatment for renal stones. We would recommend s-PCNL for patients who require an ipsilateral/contralateral endourological procedure (URS/RIRS) because it is time-efficient. All renal accesses are safe. Single MCA is recommended for complete stone clearance.

A Survey of Needle Steering Approaches in Minimally Invasive Surgery

In virtue of a curved insertion path inside tissues, needle steering techniques have revealed the potential with the assistance of medical robots and images. The superiority of this technique has been preliminarily verified with several maneuvers: target realignment, obstacle circumvention, and multi-target access. However, the momentum of needle steering approaches in the past decade leads to an open question-"How to choose an applicable needle steering approach for a specific clinical application?" This survey discusses this question in terms of design choices and clinical considerations, respectively. In view of design choices, this survey proposes a hierarchical taxonomy of current needle steering approaches. Needle steering approaches of different manipulations and designs are classified to systematically review the design choices and their influences on clinical treatments. In view of clinical consideration, this survey discusses the steerability and acceptability of the current needle steering approaches. On this basis, the pros and cons of the current needle steering approaches are weighed and their suitable applications are summarized. At last, this survey concluded with an outlook of the needle steering techniques, including the potential clinical applications and future developments in mechanical design.

Cone Beam Computed Tomography-Assisted Percutaneous Nephrolithotomy in a Hybrid Operating Room: Optimization of Patient Selection

Background: Cone beam computed tomography (CBCT) enables intraoperative cross-sectional and three-dimensional imaging of the urinary tract. CBCT in a hybrid operating room can be used for intraoperative detection of residual stones and potential additional stone extraction at the end of percutaneous nephrolithotomy (PCNL). This study describes our initial experience with intraoperative CBCT during PCNL and analyzes its role in potentially improving its outcomes. Methods: We conducted a single-center retrospective cohort study at a tertiary referral hospital between 2018 and 2021. The study aimed to evaluate the outcome of patients who underwent intraoperative noncontrast CBCT scan during PCNL. The CBCT scan was performed when the urologist determined the kidney to be endoscopically stone-free. In case any residual fragments were imaged, an additional effort was made to extract them. Patients were divided into three groups based on treatment outcome: stone-free upon CBCT, not stone-free with additional stone extraction after CBCT, and not stone-free without additional stone extraction. Procedure and patient characteristics were recorded to identify factors associated with additional stone extraction during CBCT-assisted PCNL. Results: A total of 102 procedures were included in this study. Intraoperative CBCT scans showed residual calcifications in 58 (57%) cases. In 39 cases, which is 38% of the total population and 61% of the cases with residual calcifications, one or more residual fragments imaged on the intraoperative CBCT-scan were extracted additionally within the same procedure. A higher Guy's Stone Score was associated with a higher likelihood of additionally extracting stones as a result of the CBCT. Conclusions: CBCT-assisted PCNL in a hybrid operating room can lead to additional stone extraction in the same procedure in 37% of all cases and in over 60% of the cases in which residual fragments are imaged. The value of CBCT-assisted PCNL appears to increase in the case of more complex stone surgery cases.

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.

Percutaneous nephrolithotomy vs retrograde intrarenal surgery for renal stones: a Cochrane Review

OBJECTIVES

To assess the effects of percutaneous nephrolithotomy (PCNL) vs retrograde intrarenal surgery (RIRS) for the treatment of renal stones in adults.

METHODS

We performed a comprehensive search of the Cochrane Library, MEDLINE, Embase, three other databases, trials registries, other sources of the grey literature, and conference proceedings up to 23 March 2023. We applied no restrictions on publication language or status. Screening, data extraction, risk-of-bias assessment, and certainty of evidence (CoE) rating using the Grading of Recommendations Assessment, Development and Evaluations (GRADE) approach were done in duplicate by two independent reviewers. This co-publication focuses on the primary outcomes of this review only.

RESULTS

We included 42 trials that met the inclusion criteria. Stone-free rate (SFR): PCNL may improve SFRs (risk ratio [RR] 1.13, 95% confidence interval [CI] 1.08-1.18; I2 = 71%; 39 studies, 4088 participants; low CoE). Major complications: PCNL probably has little to no effect on major complications (RR 0.86, 95% CI 0.59-1.25; I2 = 15%; 34 studies, 3649; participants; moderate CoE) compared to RIRS. Need for secondary interventions: PCNL may reduce the need for secondary interventions (RR 0.31, 95% CI 0.17-0.55; I2 = 61%; 21 studies, 2005 participants; low CoE) compared to RIRS.

CONCLUSION

Despite shortcomings in most studies that lowered our certainty in the estimates of effect to mostly very low or low, we found that PCNL may improve SFRs and reduce the need for secondary interventions while not impacting major complications. Ureteric stricture rates may be similar compared to RIRS. We expect the findings of this review to be helpful for shared decision-making about management choices for individuals with renal stones.

Is it Safe to Continue Aspirin in Patients Undergoing Percutaneous Nephrolithotomy?

OBJECTIVE

To evaluate peri-operative outcomes in patients on chronic aspirin therapy undergoing percutaneous nephrolithotomy (PCNL), with and without discontinuation of aspirin. Anti-coagulation and anti-platelet therapy are contraindications for PCNL per American Urological Association guidelines due to bleeding risk. However, there is potentially increased cardiovascular risk with peri-procedural aspirin withdrawal.

METHODS

Patients on chronic aspirin undergoing PCNL between January 2014 and May 2019 were retrospectively reviewed and stratified by continued or discontinued aspirin >5 days preoperatively. Hematologic complications, transfusions, and thrombotic complications were assessed with logistic regression model.

RESULTS

Three hundred twenty-five patients on chronic aspirin therapy underwent PCNL-85 continued and 240 discontinued aspirin. There were no significant differences in hemoglobin change, estimated blood loss, transfusions, creatinine change, thrombotic complications, 30-days re-admissions, complications, or 30-day emergency department visits. Patients who continued aspirin had longer length of stay (1.6 vs 1.9 days, P = .03). American Society of Anesthesiologists (ASA) score of 3 (OR 3.2, P = .02, 95% confidence intervals (CI) [1.2-8.4]), ASA score of 4 (OR 4.0, P = .02, 95% CI [1.2-13.1]), Black race, and previous smoking (OR 2.1, P = .02, 95% CI [1.1-3.9]) was associated with continued aspirin. Body mass index ≥30 was associated with aspirin discontinuation (OR 0.9, P = .004, 95% CI [0.9-1.0]). Increased postoperative hematologic complications were associated with additional anticoagulation medication (OR 2.9, P = .04, 95% CI [1.0-4.4]).

CONCLUSION

Continued aspirin use did not increase in postoperative complications in patients undergoing PCNL. Patients who are on additional anticoagulation medication are at risk of hematologic complications.

The Saudi urological association guidelines on urolithiasis

Aims

The Saudi Urolithiasis Guidelines are a set of recommendations for diagnosing, evaluating, and treating urolithiasis in the Saudi population. These guidelines are based on the latest evidence and expert consensus to improve patient outcomes and optimize care delivery. They cover the various aspects of urolithiasis, including risk factors, diagnosis, medical and surgical treatments, and prevention strategies. By following these guidelines, health-care professionals can improve care quality for individuals with urolithiasis in Saudi Arabia.

Panel

The Saudi Urolithiasis Guidelines Panel consists of urologists specialized in endourology with expertise in urolithiasis and consultation with a guideline methodologist. All panelists involved in this document have submitted statements disclosing any potential conflicts of interest.

Methods

The Saudi Guidelines on Urolithiasis were developed by relying primarily on established international guidelines to adopt or adapt the most appropriate guidance for the Saudi context. When necessary, the panel modified the phrasing of recommendations from different sources to ensure consistency within the document. To address areas less well covered in existing guidelines, the panel conducted a directed literature search for high quality evidence published in English, including meta analyses, randomized controlled trials, and prospective nonrandomized comparative studies. The panel also searched for locally relevant studies containing information unique to the Saudi Arabian population. The recommendations are formulated with a direction and strength of recommendation based on GRADE terminology and interpretation while relying on existing summaries of evidence from the existing guidelines.

Fluoroscopy Is Essential in Retrograde Intrarenal Surgery

Objective

This study aimed to investigate the necessity of using fluoroscopy in retrograde intrarenal surgery (RIRS). Material and Methods. A total of 612 patients who underwent RIRS for kidney stones were evaluated and divided into two groups. Group 1 routinely underwent the operation with fluoroscopy due to opaque stones (n: 504). In group 2, the procedure was performed without fluoroscopy because of nonopaque stones (n: 108). Both groups were assessed for stone size, location, and number. Success and complication rates were compared between the two groups.

Conclusion

This study was designed with the thought of not using fluoroscopy in RIRS patients with nonopaque stones and having the same stone-free rates in opaque stones. In the statistical analysis, there was no difference between the groups with and without scope for stone side, size, localization, and number; likewise, the complication rates developed in the comparison of both groups, stone-free rates, and hospital stay were the same. Discussion. Advances in the calibration of instruments, the development of optical systems, and improvements in imaging system resolution have gradually reduced the need for fluoroscopy in RIRS. This study provides further evidence that fluoroscopy is unnecessary in RIRS procedures, thereby eliminating unnecessary radiation exposure.

Percutaneous nephrolithotomy versus retrograde intrarenal surgery for treatment of renal stones in adults

BACKGROUND

Kidney stones (also called renal stones) can be a source of pain, obstruction, and infection. Depending on size, location, composition, and other patient factors, the treatment of kidney stones can involve observation, shock wave lithotripsy, retrograde intrarenal surgery (RIRS; i.e. ureteroscopic approaches), percutaneous nephrolithotomy (PCNL), or a combination of these approaches.

OBJECTIVES

To assess the effects of percutaneous nephrolithotomy (PCNL) versus retrograde intrarenal surgery (RIRS) for the treatment of renal stones in adults.

SEARCH METHODS

We performed a comprehensive search of the Cochrane Library, MEDLINE, Embase, Scopus, and two trials registries up to 23 March 2023. We applied no restrictions on publication language or status.

SELECTION CRITERIA

We included randomized controlled trials that evaluated PCNL (grouped by access size in French gauge [Fr] into three groups: ≥ 24 Fr [standard PCNL], 15-23 Fr [mini-PCNL and minimally invasive PCNL], and < 15 Fr [ultra-mini-, mini-micro-, super-mini-, and micro-PCNL]) versus RIRS.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies and extracted data from the included studies. Our primary outcomes were stone-free rate, major complications, and need for secondary interventions. Our main secondary outcomes were unplanned medical visits to emergency/urgent care or outpatient clinic, length of hospital stay, ureteral stricture or injury, and quality of life. We performed statistical analyses using a random-effects model. We rated the certainty of evidence using GRADE criteria. We adopted a minimally contextualized approach with predefined thresholds for minimal clinically important differences (MCIDs).

MAIN RESULTS

We included 42 trials assessing the effects of PCNL versus RIRS in 4571 randomized participants. Twenty-two studies were published as full-text articles, and 20 were published as abstract proceedings. The average size of stones ranged from 10.1 mm to 39.1 mm. Most studies did not report sources of funding or conflicts of interest. The main results for the most important outcomes are summarized below. Stone-free rate PCNL compared with RIRS may improve stone-free rates (risk ratio [RR] 1.13, 95% confidence interval [CI] 1.08 to 1.18; I2 = 71%; 39 studies, 4088 participants; low-certainty evidence). Based on 770 participants per 1000 being stone-free with RIRS, this corresponds to 100 more (62 more to 139 more) stone-free participants per 1000 with PCNL (an absolute difference of 10%, where the predefined MCID was 5%). Major complications PCNL compared with RIRS probably has little or no effect on major complications (RR 0.86, 95% CI 0.59 to 1.25; I2 = 15%; 34 studies, 3649 participants; moderate-certainty evidence). Based on 31 complications in the RIRS group, this corresponds to six fewer (13 fewer to six more) major complications per 1000 with PCNL (an absolute difference of 0.6%, where the predefined MCID was 2%). Need for secondary interventions PCNL compared with RIRS may reduce the need for secondary interventions (RR 0.31, 95% CI 0.17 to 0.55; I2 = 61%; 21 studies, 2005 participants; low-certainty evidence). Based on 222 secondary interventions in the RIRS group, this corresponds to 153 fewer (185 fewer to 100 fewer) secondary interventions per 1000 with PCNL (an absolute difference of 15.3%, where the predefined MCID was 5%). Unplanned medical visits No studies reported unplanned medical visits. Length of hospital stay PCNL compared with RIRS may extend length of hospital stay (mean difference 1.04 days more, 95% CI 0.27 more to 1.81 more; I2 = 100%; 26 studies, 2804 participants; low-certainty evidence). This effect size is greater than the predefined MCID of one day. Ureteral stricture or injury PCNL compared with RIRS may have little or no effect on the occurrence of ureteral strictures (RR 0.93, 95% CI 0.39 to 2.21; I2 = 0%; 13 studies, 1574 participants; low-certainty evidence). Based on 14 ureteral strictures in the RIRS group, this corresponds to one fewer (nine fewer to 17 more) ureteral strictures per 1000 with PCNL (an absolute difference of 0.1%, where the predefined MCID was 2%). Quality of life No studies reported quality of life.

AUTHORS' CONCLUSIONS

Based on a large body of evidence from 42 trials, we found that PCNL compared with RIRS may improve stone-free rates and may reduce the need for secondary interventions, but probably has little or no effect on major complications. PCNL compared with RIRS may have little or no effect on ureteral stricture rates and may increase length of hospital stay. We found no evidence on unplanned medical visits or participant quality of life. Because of the considerable shortcomings of the included trials, the evidence for most outcomes was of low certainty. Access size for PCNL was less than 24 Fr in most studies that provided this information. We expect the findings of this review to be helpful for shared decision-making about management choices for individuals with renal stones.

The effect of standard percutaneous nephrolithotomy, miniaturized percutaneous nephrolithotomy and retrograde intrarenal surgery on biomarkers of renal injury: a randomized clinical trial

Background

Observational studies on the association of endourological procedures with renal parenchymal damage are lacking. This randomized trial examined the effect of standard percutaneous nephrolithotomy (sPCNL) in comparison with miniaturized-PCNL (mini-PCNL) and retrograde intrarenal surgery (RIRS) for nephrolithiasis treatment on novel biomarkers of renal injury.

Methods

Seventy-five patients were randomized in a 1:1:1 ratio to receive sPCNL, mini-PCNL and RIRS for nephrolithiasis. The ratios of neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1) and interleukin-18 (IL-18) normalized for urinary creatinine (Cr) were calculated from urine samples collected at baseline (2-h preoperatively) and at 2-, 6-, 24- and 48-h postoperatively. Two-way mixed analysis of variance (ANOVA) for repeated measurements was used to evaluate the effects of type of procedure and time on studied biomarkers.

Results

Between baseline and 2-h postoperatively, no significant differences were observed in NGAL/Cr changes between sPCNL [median (interquartile range) 9.46 (4.82-14.9)], mini-PCNL [12.78 (1.69-25.24)] and RIRS [6.42 (2.61-23.90)] (P = .902). Similarly, no between-group differences were observed for KIM-1/Cr (P = .853) and IL-18 (P = .980) at 2 h, and all biomarkers at any time-point postoperatively. Within-groups, significant increases from baseline were noted for NGAL/Cr (sPCNL, P < .001; mini-PCNL, P < .001; RIRS, P = .001), KIM-1/Cr and IL-18/Cr at 2 h; progressively lower increases from baseline were noted in all groups for KIM-1/Cr and IL-18/Cr at 6-, 24- and 48-h postoperatively. As such, a significant effect of time but not of type of procedure was evidenced with two-way mixed ANOVA. No significant between-group differences were observed in acute kidney injury incidence and complications.

Conclusions

The endourological procedures under study are associated with similar patterns of early tubular injury, detected by novel biomarkers, which is largely reduced within 48 h and no changes in glomerular function.

Pure uric acid stone prediction model using the variant coefficient of stone density measured by thresholding 3D segmentation-based methods: A multicenter study

Urinary stones are common urological diseases with increasing prevalence and incidence worldwide. Among the various types of stones, uric acid stones can be dissolved by oral chemolysis without any surgical procedure. Therefore, our study demonstrates that variant coefficient of stone density measured by thresholding a three-dimensional segmentation-based method from noncontrast computed tomography images can be used to identify pure uric acid stones from non-pure uric acid stones. This study provides a preoperative pure uric acid stone prediction model that could reduce invasive procedural treatments. The pure uric acid stone prediction model may offer optimized clinical decision-making for patients with urinary stones.

BACKGROUND AND OBJECTIVES

While most urinary stones are managed with interventional therapy, uric acid (UA) stones can be dissolved by oral chemolysis without invasive procedures. This study aimed to develop and validate a pure UA (pUA) stone prediction model using a variant coefficient of stone density (VCSD) measured by thresholding a three-dimensional (3D) segmentation-based method.

METHODS

Patients with urolithiasis treated at Keimyung University Dongsan Hospital between January 2017 and December 2020 were divided into training and internal validation sets, and patients from Kyungpook National University Hospital between January 2017 and December 2018 were used as an external validation set. Each stone was segmented by a thresholding 3D segmentation-based method using an attenuation threshold of 130 Hounsfield units. VCSD was calculated as the stone heterogeneity index divided by the mean stone density.

RESULTS

A total of 1175 urinary stone cases in 1023 patients were enrolled in this study. Of these, 224 (19.1%) were pUA stone cases. Among the potential predictors, thresholding 3D segmentation-based VCSD, age, sex, radio-opacity, hypertension, diabetes, and urine pH were identified as independent pUA stone predictors, and VCSD was the most powerful indicator. The pUA stone prediction model showed good discrimination, yielding area under the receiver operating characteristic curve of 0.960 (95% confidence interval (CI): 0.940-0.979, P < 0.001), 0.931 (95% CI: 0.875-0.987, P < 0.001), and 0.938 (95% CI: 0.912-0.965, P < 0.001) in the training, internal validation, and external validation sets, respectively.

CONCLUSIONS

VCSD measured using 3D segmentation was a decisive independent predictive factor for pUA stones. Furthermore, the established prediction model with VCSD can serve as a noninvasive preoperative tool to identify pUA stones.

A systematic review and meta-analysis of outcomes between dusting and fragmentation in retrograde intrarenal surgery

OBJECTIVES

Comparing stone-free rates and associated outcome measures between two surgical modalities of lithotripsy fragmentation and removal or spontaneous passage of dust during retrograde intrarenal surgery (RIRS).

METHODS

In March 2023, we conducted a literature search in several widely used databases worldwide, including PubMed, Embase, and Google Scholar. We only considered English articles and excluded pediatric patients. Reviews and protocols without any published data were excluded. We also excluded articles with conference abstracts and irrelevant content. We used the Cochran-Mantel-Haenszel method and random-effects models to assess inverse variances and 95% confidence intervals (CIs) for mean differences in categorical variables. The results were reported as odds ratios (ORs) and 95% CIs. Statistical significance was set at p < 0.05.

RESULTS

Our final meta-analysis included nine articles, comprising two randomized controlled trials (RCTs) and seven cohort studies. The total number of patients included in these studies was 1326, and all studies used holmium laser lithotripsy. The pooled analysis of the dust and fragmentation groups showed that the fragmentation group had a higher stone-free rate (OR 0.6; 95% CI 0.41 - 0.89; p = 0.01); the dust group had a shorter operative time (WMD - 11.6 min; 95% CI - 19.56 - -3.63; p = 0.004); and the dust group had a higher retreatment rate (OR 2.03; 95% CI 1.31 - 3.13; p = 0.001). There was no statistically significant difference between the two groups in terms of length of hospital stay, overall complications, or postoperative fever.

CONCLUSIONS

Our results showed that both procedures could be safely and effectively used for upper ureteral and renal calculi lithotripsy, the dust group had potential advantages over the fragmentation group in terms of the operation time, and the fragmentation group had certain advantages in terms of stone-free rate and retreatment rate.

Effect of patient positioning on anesthesiologic risk in endourological procedures

Objective

The objective is to compare supine and prone positions in terms of arterial blood gas during lithotripsy endourology procedures in different stages.

Material and Methods

Cases of during lithotripsy endourology procedures in our department from March to September 2020 were included prospectively. The variables registered were body mass index, age, the American Society of Anesthesiologists (ASA) score, diabetes mellitus, positive end-expiratory pressure (PEEP), FiO2, stone size, stone location, procedural type, position, procedure duration, PaO2, SaO2, PaCO2, pH, and dynamic compliance. PaO2, SaO2, PaCO2, pH, and dynamic compliance were recorded at the beginning of the procedure, 5 min later, 15 min later, and at the end of the procedure.

Results

Thirty patients in prone position and 30 in lithotomy position were included in this study. Patients in prone position underwent percutaneous nephrolithotomy, and patients in supine/lithotomy underwent retrograde intrarenal surgery or ureteroscopy. Statistically significant differences were found in PEEP, duration, PaO2 at the beginning, SaO2 at the beginning and at the end of the procedure, PaCO2 at the beginning and at minute 5 and pH at the beginning of the surgery. The saturation PaO2 increased significantly on prone position and was statistically significantly better at the end of the surgery.

Conclusions

Both prone and supine positions were safe regarding anesthesiologic risk and had no clinically relevant differences in terms of individual comparisons in arterial blood gas parameters in static moments of the procedure. Prone position was related to an increase in PaO2 and a drop in PaCO2 gradually from the beginning to the end of the surgery.

Stone attenuation on computer tomography helps surgeons make decisions between miniaturized percutaneous nephrolithotomy or retrograde intrarenal surgery for lower pole stones: a retrospective study

A retrospective study was performed on 200 patients who underwent miniaturized percutaneous nephrolithotomy (mini-PCNL) or retrograde intrarenal surgery (RIRS) for 10-20 mm sized lower pole renal calculi to investigate the relationship between computed tomography (CT) attenuation of calculi and surgical outcomes. CT was used to examine the location, size, and CT attenuation values of the calculi. Additionally, the operation time, hospital stay, hemoglobin (Hb) reduction, stone-free rate (SFR), and complication rate were also meticulously documented and subjected to comparative analysis. Complications were assessed using the Clavien-Dindo grading system. We observed no significant differences in hospitalization data and follow-up outcomes, except for a longer hospital stay and higher Hb drops in patients receiving mini-PCNL. Statistical analysis revealed an association between CT attenuation and operation time. Compared with mini-PCNL, RIRS could reduce bleeding, hospital stay, surgery time, and complications for 10-20 mm sized lower pole kidney stones with CT values < 1000 HU. RIRS resulted in longer operation time and lower stone-free rates despite shorter hospital stays and less bleeding than mini-PCNL for stones with CT values > 1000 HU. Therefore, selecting an appropriate surgical method based on CT attenuation might improve outcomes. For patients with stone attenuation values < 1000 HU, RIRS is the recommended option. When stone attenuation values > 1000 HU, the surgical method should be chosen based on the patient's individual situation.

A Comparative Study on Outcomes of Retrograde Intrarenal Surgery (RIRS), Mini Percutaneous Nephrolithotomy (PCNL), and Extracorporeal Shock Wave Lithotripsy (ESWL) for Lower Pole Renal Calculi of < 1.5 cm

Background: Percutaneous nephrolithotomy (PCNL), established in the 1970s, has replaced open surgery for large stones. Extracorporeal shock wave lithotripsy (ESWL), once the preferred first-line treatment for small-to-medium-sized renal stones, has a questionable charm owing to patient reluctance for repeated treatments and hospitalizations since ESWL has a reduced stone-free rate (SFR). Flexible ureterorenoscopy, also referred to as RIRS, originally applied in the management of lower pole stones resistant to ESWL, is increasingly being used as a primary modality to manage lower pole stones, and it may potentially achieve higher SFR than ESWL and lower morbidity than PCNL for patients with low-volume stone diseases. Objectives: Observations were made to compare ESWL, mini PCNL, and RIRS in managing lower pole renal calculi of < 1.5 cm. Methods: This observational study encompassed all patients with lower pole renal stones with < 1.5 cm diameter and < 1000 HU density who underwent mini PCNL, RIRS, or ESWL from January 2020 to July 2021. There were 40, 60, and 60 patients in the RIRS, mini PCNL, and ESWL groups, respectively, for all of whom preoperative CT urogram was performed. The patients were informed of the procedures, and their informed consent was obtained. The stone-free rates of the three modalities were compared, and the outcomes were statistically analyzed. Results: The mean stone sizes in the present study were 12.99 × 3.56 mm in mini PCNL, 10.62 × 2.51 mm in RIRS, and 10.93 × 3.13 mm in ESWL. The mini PCNL group's SFR was significantly higher than those of other groups: 59 (98.3%) in mini PCNL, 34 (85%) in RIRS, and 46 (76.7%) in ESWL (P = 0.002). Out of the 60 patients in the mini PCNL group, only one (1.7%) required an ancillary procedure, while only six (10%) out of 40 patients in the RIRS group and 11 (18.33%) out of 60 patients in the ESWL group required the ancillary procedure (P = 0.031). Conclusions: For lower pole renal calculi < 1.5 cm, mini PCNL has the highest SFR, followed by RIRS and ESWL, in sequence. The ancillary procedure rate was 18.33% in the ESWL group, which was higher than those of mini PCNL (1.7%) and RIRS (10%).

Management of large kidney stones in the geriatric population

PURPOSE

The aim of this review is to highlight the unique factors that predispose geriatric patients to nephrolithiasis and to compare the utility and efficacy of surgical techniques in this specific patient population.

METHODS

PubMed and EMBASE databases were reviewed, and studies were organized according to surgical treatments.

RESULTS

Few prospective studies exist comparing kidney stone removal in the elderly to younger cohorts. In addition, various age cut-offs were used to determine who was considered elderly. Most studies which analyzed Percutaneous Nephrolithotomy (PCNL) found a slightly higher rate of minor complications but comparable stone free rate and operative time. For ureteroscopy (URS) and extracorporeal shockwave lithotripsy (ESWL), there were minimal complications observed and no difference in clinical success in the elderly. All surgical techniques were presumed to be safe in the elderly and most found no difference in stone-free rates.

CONCLUSIONS

Unique attributes of the geriatric population contribute to stone formation and must be considered when determining appropriate management modalities. This review provides an overview of the utility and efficacy of PCNL, URS and ESWL in the elderly, as well as a porposed algorithm for management in this population.

Learning curve in flexible ureteroscopy for renal stones: A propensity score-matched study

OBJECTIVE

To assess the learning curve and evaluate the impact of surgical experience related to the outcomes of flexible ureteroscopy (fURS) for upper urinary tract stones.

METHOD

We evaluated retrospectively lithiasis fURS performed in our institution between January 2004 and December 2020. Patients were divided into two groups by the number of procedures performed by surgeon. Group 1 (G1) included the first 50 procedures, and group 2 (G2) the next cases. These groups were matched on baseline characteristics by a propensity score. Stones free rate (SFR) and complication rate (CR) were compared. Learning curves were realized using logistic curve with 95% confidence interval.

RESULTS

After criteria exclusion and propensity score matching, 1548 procedures were analyzed (1:1, G1 and G2, n=774 procedures). A total of 29 surgeons were evaluated. The overall SFR was 68.4% without statistical difference between the two groups (G1=67.9% vs. G2=68.8%, P=0.72). The surgeon's experience was not associated with SFR (OR=1.15, 95% CI: 0.90-1.47), except in subgroup stones>2cm (OR=2.89, 95% CI: 1.29-6.46). The overall CR was 12.5%, mainly Clavien-Dindo grade I-II complications (96.2%). Surgical experience was not associated with CR (OR=1.06, 95% CI: 0.77-1.45). The overall logistic curves for probability of stone clearance and complication tended to be a flat slope.

CONCLUSION

Impact of surgical experience on fURS for UUTS was not associated with SFR and CR. However, for stones larger than 2cm, surgeon's experience tended to be associated with SFR, but without impact on overall complications.

LEVEL OF EVIDENCE: 3

Influencing factors of acute kidney injury following retrograde intrarenal surgery

PURPOSE

To investigate the influencing factors of acute kidney injury (AKI) following retrograde intrarenal surgery (RIRS).

METHODS

The data of patients who underwent RIRS for kidney stones between January 2018 and June 2022 at two tertiary centers were retrospectively analyzed. Demographic data of patients were obtained. According to kidney disease: Improving Global Outcomes (KDIGO) criteria, those with and without AKI were divided into two groups. Preoperative, intraoperative, and postoperative predictive factors of patients were investigated between the groups. In addition, the influencing factors of AKI were examined by multivariate analysis.

RESULTS

This study included 295 (35.7%) women and 532 (64.3%) men. The mean age was 50.03 ± 15.4 years (range 18-89), and mean stone size was 15.5 ± 6.1 mm (range 6-47). Overall, 672 of patients (81.3%) were stone-free after the initial treatment. According to KDIGO, 110 of patients (13.3%) had AKI during the postoperative period. Univariate analysis showed that stone size (P = .003), previous stone surgery (P = .010), renal malformations (P = .017), high operative time (P =  < .001), high preoperative creatinine value (P = .036), intraoperative complications (P = .018), and postoperative urinary tract infection (P = .003) had significant influence on the AKI after RIRS. Multivariate analysis excluded previous stone surgery, high preoperative creatinine value, renal malformations, and intraoperative complications from the logistic regression model, whereas other factors maintained their statistically significant effect on AKI, indicating that they were independent predictors.

CONCLUSIONS

Stone size, operative time, postoperative urinary tract infection, and diabetes mellitus are significant predictors of AKI. During RIRS, urologists should consider the factors that increase the risk of AKI and evaluate the treatment outcomes based on these factors.

Development and Validation of the Prediction Model of Sepsis in Patients After Percutaneous Nephrolithotomy and Sepsis Progresses to Septic Shock

Background: To study the predictors of sepsis and the progression of sepsis to septic shock in patients after percutaneous nephrolithotomy (PCNL) and to establish and validate predictive models. Methods: The patients were assigned to either the development cohort or the validation cohort depending on their hospital. In the development cohort, univariate and multivariate logistic regression analyses were used to screen independent risk factors for sepsis after PCNL and sepsis progression to septic shock. Nomogram prediction models were established according to the related independent risk factors. Areas under the receiver operating characteristic curves, calibration plots, and decision curve analysis (DCA) were used to estimate the discrimination, calibration, and clinical usefulness of the prediction models, respectively. The two sets of models were further validated on the validation cohort. Results: In the development cohort, the risk factors for sepsis after PCNL were diabetes, urine nitrite, staghorn calculi, HU value, albumin-globulin ratio, and high-sensitivity C-reactive protein/albumin ratio. The pre- and postoperative white blood cell counts were risk factors for the progression of sepsis to septic shock. The area under the ROC curve value for predicting sepsis risk was 0.891 and that for predicting septic shock risk was 0.981 in the development cohort; in the validation cohort, these values were 0.893 and 0.996, respectively. In the development cohort, the calibration test p values in the sepsis and septic shock cohorts were 0.946 and 0.634, respectively; in the validation cohort, these values were 0.739 and 0.208, respectively. DCA of the model in the sepsis and septic shock cohorts showed threshold probabilities of 10%-90% in the development cohort; in the validation cohort, these values were 10%-90%. Conclusion: The individualized nomogram prediction models can help improve the early identification of patients who are at higher risk of developing sepsis after PCNL and the progression of sepsis to septic shock to avoid further damage.

A robust localization approach for Percutaneous Nephrolithotomy (PCNL): A single-center retrospective study

BACKGROUND

Percutaneous Nephrolithotomy (PCNL) represents the gold standard treatment method for cases with large kidney stones. As a critical step in performing PCNL, the procedure of establishing a safe and accurate nephrostomy tract will dramatically impact the treatment quality of patients with large-sized kidney stones.

OBJECTIVE

This work attempts to describe a new and improved process of establishing an accurate nephrostomy tract and clinically evaluate the effectiveness and safeness of this proposed methodology.

METHODS

This work represents a retrospective single-center study carried out between August 2013 and November 2019. The collected samples consist of 937 patients who were operated on using PCNL coupled with our proposed procedure. Briefly, a preoperative B-ultrasonography was firstly performed to decide the puncture point in a simulated surgical position where was marked with ureteral catheter segments (2-3 cm). A computed tomography (CT) scan was followed to correct the anchor points in the simulated surgical position. After this, an accurate puncture operation was performed under the real-time guidance of intraoperative B ultrasound.

RESULTS

Examining this study, 851 subjects with renal stones and 86 subjects with ureteropelvic junction stones were included for the PCNL operation project. All samples were grouped with Guy's grading system: grade I, II, III, and IV patients there were 0.00%, 42.69%, 51.01%, and 6.30%, respectively. Among these patients, the average age was 48.49 ± 10.80 years old, with a male to female ratio of around 1.73:1.

CONCLUSIONS

This study showed that our developed method warrants an accurate and safe PCNL operation that involves the process of establishing the nephrostomy tract. Other advantageous attributes of this new PCNL process include negligible radiation exposure, lesser complications, and low failure rates. More importantly, this new localization approach is particularly attractive for hospitals that are new to the field of adopting PCNL considering its safeness, effectiveness, and learnability.

Evaluation of the Effectiveness of Interventions on Nephrolithiasis in Transplanted Kidney

CONTEXT

De Novo nephrolithiasis in renal transplant can have severe consequences since renal transplantation involves a single functioning kidney with medical and anatomical specificities (heterotopic transplantation on iliac vessels, immunosuppressive treatments, and comorbidities).

OBJECTIVE

To systematically review all available evidence on the prevalence of de novo nephrolithiasis in renal transplant, presentation, and stone characteristics, and to report in a meta-analysis the efficacy of stone treatments (extracorporeal shock wave lithotripsy [ESWL], medical treatment, percutaneous nephrolithotomy [PCNL], open surgery, and ureteroscopy).

EVIDENCE ACQUISITION

Medline, Embase, and the Cochrane Library were searched up to November 2021 for all relevant publications reporting the management of de novo nephrolithiasis in renal allografts. The primary outcome was stone-free rate (SFR) at 3 mo. Secondary outcomes included prevalence, stone characteristics (size, density, and composition), symptoms on presentation, need for drainage, complications, and recurrence. Data were narratively synthesized in light of methodological and clinical heterogeneity, and a meta-analysis was performed for SFR. The risk of bias of each included study was assessed.

EVIDENCE SYNTHESIS

We included 37 retrospective studies with 553 patients and 612 procedures; of the 612 procedures 20 were antegrade ureteroscopy, 154 retrograde ureteroscopy, 118 PCNL, 25 open surgery, 155 ESWL, and 140 surveillance/medical treatment. The prevalence of nephrolithiasis in renal transplant was 1.0%. The mean stone size on diagnosis was 11 mm (2-50). The overall SFR at 3 mo was 82%: 96% with open surgery, 95% with antegrade ureteroscopy, 86% with PCNL, 81% with retrograde ureteroscopy, and 75% with ESWL.

CONCLUSIONS

De novo nephrolithiasis in renal transplant is an infrequent condition. A high SFR were obtained with an antegrade approach (ureteroscopy, PCNL, and open approach) that should be considered in renal transplant patients owing to the heterotopic position of the renal graft. The choice of technique was correlated with stone size: generally ureteroscopy and ESWL for stones 11-12 mm (mean stone size) versus PCNL and open surgery for 17-25 mm stones.

PATIENT SUMMARY

De novo nephrolithiasis in renal transplants is an infrequent situation that can have severe consequences on the function of the renal graft. We evaluated the efficacy of each treatment and noted that antegrade approaches (open surgery, percutaneous nephrolithotomy, and antegrade ureteroscopy) were associated with the highest stone-free rate. As opposed to the management of nephrolithiasis in native kidney, an antegrade approach should be considered more in renal transplant patients.

In Vivo Feasibility Test of a New Flexible Ureteroscopic Robotic System, easyUretero, for Renal Stone Retrieval in a Porcine Model

PURPOSE

Using a new robotic endoscopic platform system developed for retrograde intrarenal surgery (RIRS) called easyUretero (ROEN Surgical Inc.), we evaluated the feasibility and safety of renal stone retrieval in a porcine model.

MATERIALS AND METHODS

Six female pigs were used for our in vivo study. First, 0.3-cm-sized phantom stones were inserted into the kidneys of each pig via the ureteral access sheath. Next, renal stone retrieval was attempted using manual RIRS in three pigs and robotic RIRS in three pigs. Three surgeons performed extraction of 10 stones in each session.

RESULTS

The mean stone retrieval time by manual RIRS was significantly shorter than that by robotic RIRS (399.9±185.4 sec vs. 1127.6±374.5 sec, p=0.001). In contrast, the questionnaire regarding usability showed high satisfaction in the surgeons' fatigue category for surgeons using robotic RIRS. The radiation exposure dose was also lower in robotic RIRS than in manual RIRS (0.14 µSv vs. 45.5 µSv). Postoperative ureteral injury assessment revealed Grade 0 in manual RIRS cases and Grades 0, 1, and 2 in robotic RIRS cases.

CONCLUSION

The easyUretero system is a new robotic RIRS system that was developed in Korea. The results of the present study suggest that using easyUretero for stone retrieval during RIRS is safe and ergonomic.

Feasibility of Laser Lithotripsy for Midsize Stones Using Robotic Retrograde Intrarenal Surgery System easyUretero in a Porcine Model

Purpose: To test the safety and feasibility of laser lithotripsy for midsize renal stones using a newly developed robotic retrograde intrarenal surgery (RIRS) system (easyUretero) in a porcine model. Materials and Methods: Three urologic surgeons representing three different RIRS experience levels (beginner, intermediate, and expert) participated. Four female pigs (aged 6 months) underwent manual or robotic RIRS. Under general anesthesia, a nephrostomy tract was created ventrally, and calcium stones (diameter, 1.0-1.5 cm) were inserted at renal calices. For manual RIRS, surgeons operated a flexible ureteroscope. For robotic RIRS, the ureteroscope was attached to the robotic slave device. The Auriga XL™ Holmium laser was used for lithotripsy. Lasering and stone retrieval time were measured. Kidneys and ureters were inspected for injury at the end of each session. Results: For the expert, both lasering and stone retrieval by manual RIRS were quicker than by robotic RIRS (22.8 ± 11.0 s/stone vs 234.5 ± 102.5 s/stone, p = 0.02; 41.5 ± 0.5 s/stone vs 79.3 ± 8.1 s/stone, p = 0.02). For the intermediate and beginner, lasering and stone retrieval times were not significantly different between manual and robotic procedures (127.8 ± 93.2 s/stone vs 284.8 ± 112.3 s/stone, p = 0.08; 86.0 ± 30.5 s/stone vs 84.1 ± 21.4 s/stone, p = 0.92). All stones were removed. Grade 1 ureteral and renal injuries occurred in both manual RIRS and robotic RIRS. Conclusions: The laser lithotripsy using the easyUretero robotic system is safe and feasible in a porcine model, even for less-experienced surgeons.

[Urolithiasis-Therapy and recurrence prevention taking into account gender-specific aspects]

The prevalence of urolithiasis is steadily increasing worldwide in both genders. Diet and lifestyle, such as the rising prevalence of obesity and other metabolic syndrome traits, are considered key factors in this trend. Gender differences as a result of interventional therapy for urolithiasis have not been observed. However, iatrogenic injury to the male urethra is considered the most common reason for urethral strictures after endourologic (stone) therapy. In contrast, sepsis, as the major cause of urinary stone-related mortality, is more frequently reported in women after ureterorenoscopy and percutaneous nephrolithotomy. There are also differences in the frequency of various types of stones between men and women. Calcium oxalate and uric acid stones are more commonly observed in men, while carbonate apatite and struvite are diagnosed more often in women. Urinary stone analysis is therefore paramount for successful recurrence prevention. Diagnosis is based on the assignment of patients to the low-risk or high-risk group. The medical nutrition and pharmacological measures for the therapy of the respective type of stone are based on the risk factors in 24 h urine samples. A personalized approach that accounts for gender differences could further improve treatment, and recurrence prevention decisions for urinary stones.

Systematic review on active treatment for urinary fistula after partial nephrectomy

INTRODUCTION

Urinary fistula is expected to become more frequent in urological practice as a result of expanding indication of partial nephrectomy given it's oncological results equivalent to those of radical nephrectomy but at a lower risk of progression to chronic kidney disease, lower cardiovascular morbidity, and overall mortality.

OBJECTIVES

Review and compare different techniques of contemporary active management for urinary fistula after partial nephrectomy.

METHODS

A systematic literature search on the MEDLINE database was conducted in March 2020, combining the terms: "urine leak", "urine leakage", "urinary leak" and "urinary fistula", with: "partial nephrectomy", "nephron sparing surgery" and "renal sparing surgery". This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Only articles related to active treatment were eligible. Abstracts in English and Spanish from the last two decades were screened. No restriction based on study design nor the length of follow-up.

PRIMARY OUTCOMES

1) Leak resolution rate 2) Time course of leak resolution and 3) Number of interventions needed for resolution.

RESULTS

Multiple studies were found. There were no randomized controlled trials. Urinary fistula can be solved in many ways with active treatment, with a high success rate (97.5%), an average of 1.4 intervention-per-patients and a mean time for leak resolution of 11 days (median of 3 days).

CONCLUSION

There is a high risk of bias due to the study's methodology. There is a broad range of effective alternatives and various approaches to solve urinary fistula in an appropriate timing.

Comparative efficacy and safety between Micro-Percutaneous Nephrolithotomy (Micro-PCNL) and retrograde intrarenal surgery (RIRS) for the management of 10–20 mm kidney stones in children: A systematic review and meta-analysis

Objectives

Kidney stone in children is a recurring problem that requires multiple interventions over time. Minimally-invasive approach, such as Extracorporeal Shockwave Lithotripsy (ESWL) is recommended for moderately-sized stones. However, since ESWL is associated with multiple interventions, Micro-Percutaneous Nephrolithotomy (Micro-PCNL) and Retrograde Intrarenal Surgery (RIRS) can also be considered to treat kidney stones in pediatric patients. Both approaches have their respective advantages and disadvantages. In this study, we aimed to compare the efficacy and safety of Micro-PCNL and RIRS in pediatric patients with kidney stones.

Methods

This systematic review and meta-analysis adhered to the PRISMA guideline and Cochrane Handbook of intervention. The included studies were obtained from the PubMed and ScienceDirect databases. The protocol of this review has been registered in PROSPERO (CRD42021265894). The quality of the studies was assessed using the Newcastle-Ottawa Scale, outcomes were analyzed using STATA®16, and certainty of evidence was evaluated using GRADE.

Results

A total of 239 participants were included in this study, divided into the Micro-PCNL (n = 112) and RIRS (n = 127) procedure groups. Statistical analysis revealed a significantly lower requirement of postoperative stenting procedure in Micro-PCNL compared to RIRS (OR 0.09; 95%CI 0.02, 0.47; p < 0.01). However, no significant difference was found in stone-free rate (p = 0.86), operative time (p = 0.09), UTI incidence (p = 0.67), blood transfusion requirement (p = 0.95), and length of stay (p = 0.77).

Conclusion

Micro-PCNL is superior to RIRS in managing pediatric kidney stones,10–20 mm in size based on their comparable SFR and fewer requirements of additional stenting procedures.

•

Micro-PCNL had a comparable SFR to RIRS in managing pediatric kidney stones,10–20 mm.

•

Micro-PCNL had less requirement of stenting procedure than RIRS in managing pediatric kidney stones,10–20 mm.

•

Micro-PCNL is superior to RIRS in managing pediatric kidney stones,10–20 mm.

Could retrograde intrarenal surgery be a safe and effective alternative to mini-percutaneous nephrolithotomy ın the management of relatively large (20-30 mm) stones? A critical evaluation

PURPOSE

To compare the outcomes of mini-percutaneous nephrolithotomy (mPCNL) and retrograde intrarenal surgery (RIRS) in patients with renal stones sizing 2-3 cm.

METHODS

A total of 566 patients from 6 institutions who underwent mPCNL (n = 440) and RIRS (n = 126) procedures were enrolled in our study. The retrospective patient cohort was reviewed and compared. Binary logistic regression analysis was performed to determine factors predicting success in the RIRS group.

RESULTS

The stone-free rates were 91.1 and 77% for the mPCNL and RIRS groups, respectively (p < 0.001). The auxiliary procedure rates were 4.5 and 39.7% in the mPCNL and RIRS groups, respectively (p < 0.001). Mean values of hemoglobin decrease, fluoroscopy time, and hospitalization time were significantly higher in the mPCNL group (p < 0.001). While the Clavien grade 1-2 complication rates were 10.9 and 34.1% (p < 0.001) in two groups, these values were 2.7 and 1.6% (p = 0.539), respectively, for Clavien grade 3-4 complication rates. Although three patients in the mPCNL group received blood transfusions, none of the patients in the RIRS groups were transfused. The stone location and stone density parameters were found to be the independent predictive factors for RIRS success.

CONCLUSIONS

mPCNL provided a higher stone-free rate, less need for the auxiliary procedure, and lower complication rates compared to RIRS in patients with 2-3 cm stones. Blood loss, radiation exposure, and a hospital stay of mPCNL can be significantly reduced with the RIRS technique in selected patients.

Comparison of renal parenchymal trauma after standard, mini and ultra-mini percutaneous tract dilation in porcine models

OBJECTIVE

To evaluate whether reducing tract dilation diameter in PCNL (percutaneous nephrolithotomy) procedures results in minimizing of renal trauma of the percutaneous tract.

METHODS

A percutaneous renal access tract was established bilaterally to 11 pigs. Two pigs were euthanized immediately after the experiment, while nine pigs were sacrificed 1 month later. The percutaneous accesses were dilated up to 30Fr, 22Fr or 12Fr. The animals underwent a contrast-enhanced computer tomography immediately after the procedure and 30 days later. DMSA-scintigraphy with SPECT-CT was also performed. The kidneys of all animals were harvested for histological evaluation. The volume of scar tissue and the percentage of renal volume replaced by scar tissue were calculated.

RESULTS

Immediate post-procedural CT-scans revealed a significant difference in defect diameter among the three modalities. However, the scar volume calculated on CT-images and histopathology showed a significant difference only when 30Fr dilation was compared to 12Fr dilation. The percentage of scar volume was negligible in all cases, but there was still a statistical difference between 30 and 12Fr dilation. Dilation up to 22Fr revealed no statistical differences compared to the other two modalities. DMSA-scintigraphy showed no scar tissue in any case.

CONCLUSION

Dilation up to 30Fr may cause a significantly larger scar tissue on renal parenchyma compared to 12Fr dilation as it was shown on CT-images and microscopic evaluation, but based on the DMSA/SPECT-CT this difference seems to be insignificant to the renal function. The scar tissue caused by 22Fr dilation seemed to have no significant difference from the other modalities.

Presence of a Novel Anatomical Structure May Cause Bleeding When Using the Calyx Access in Mini-Percutaneous Nephrolithotomy

Background

Fused renal pyramid (FRP) is a kidney anatomical structure which was first identified by us. The vascular anatomy of FRP exhibits different from that of the normal renal pyramid (NRP), manifested by the distribution of the ectopic interlobar arteries in FRP. In this study, we analyzed the effect of FRPs on bleeding when using calyx access in mini-percutaneous nephrolithotomy (PCNL).

Patients and Methods

Overall, 633 patients who underwent ultrasound-guided single-tract mini-PCNL were divided into two groups according to the puncture method used: in group A, puncture was performed through the axial direction of the renal calyx, the line from the apex of the fornix to the center of the neck plane under B-mode ultrasound guidance; and in group B, Doppler ultrasound-guided axillary puncture through calyces corresponding to NRPs when the plane of renal column blood vessels on both sides was selected or calyx puncture through the hypovascular area of the FRPs. Relevant demographic and clinical data were retrospectively analyzed.

Results

The two groups exhibited similar baseline characteristics. No significant differences were found in hemoglobin reduction, puncture site, tract size, postoperative creatinine level, or stone-free rate between the two groups (P > 0.05). Blood transfusion and embolization rates in group B were significantly lower than those in group A (P = 0.03 and 0.045, respectively). No differences were found between the two groups in terms of persistent pain, hydrothorax, fever, subcapsular hematoma, and urosepsis (P > 0.05). The overall complication rate was not significantly different between the two groups (P = 0.505).

Conclusions

FRP is a non-negligible anatomical structure that may cause hemorrhage when using calyx access. Doppler ultrasound can identify ectopic blood vessels in FRPs to reduce bleeding during calyx access in mini-PCNL procedures.

Ultramini-percutaneous nephrolithotomy versus retrograde intrarenal surgery in the treatment of 10-30 mm calculi: a randomized controlled trial

The surgical management of renal stones 10-30 mm is usually performed with percutaneous nephrolithotomy (PCNL) and retrograde intrarenal surgery (RIRS). Standard form of percutaneous nephrolithotomy has paved the way for miniaturized PCNL in many centres. We wanted to evaluate the efficacy, safety and the cost-effectiveness of ultramini-percutaneous nephrolithotomy (UMP) versus RIRS in the treatment of renal stones with stone burden 10-30 mm. Patients with renal stone burden 10-30 mm were prospectively randomized into either UMP or RIRS. The demographic data, stone characteristic, operative time and cost of the equipment were recorded. The stone free status, analgesic requirement, deterioration of the renal function and hemoglobin and the postoperative complications as per Clavein-Dindo grade were recorded. One hundred and fifty patients met inclusion criteria. Out of these 98 underwent UMP and 46 RIRS. Six withdrew the consent before the procedure. Mean stone size was comparable in either of the groups. Mean laser time and stone extraction time was significantly less for UMP compared to RIRS (41.17 min versus 73.58 min p < 0.0001). Mean consumable costs in the UMP group were considerably less at US$45.73 compared to the RIRS group at $423.11 (p < 0.0001). The stone free rates at 1 month of follow-up were 100% for UMP group and 73% for RIRS group. There were insignificant changes to mean hemoglobin and glomerular filtration rate (GFR) in all patients and the average length of the stay was similar in both the groups. The postoperative complications revealed Grade I and II rate of 10% in the UMP group and 35% in the RIRS group, respectively. We concluded that UMP to be safe, effective and more economical to the RIRS for renal stones up to 3 cm in size.Trial registered with ISRCTN registry ID ISRCTN20935105, Retrospective.

Using Intraoperative Portable CT Scan to Minimize Reintervention Rates in PCNL: A Prospective Trial

BACKGROUND AND PURPOSE

More than 40% of patients undergoing PCNL are left with residual stone fragments and often require secondary procedures. Portable CT (PCT) technology allows surgeons to obtain intraoperative cross-sectional imaging, identify and extract residual stones immediately, and thereby reduce the need for subsequent procedures. This prospective trial evaluates how incorporation of PCT during PCNL affects perioperative outcomes.

PATIENTS AND METHODS

We prospectively enrolled eligible patients undergoing initial PCNL for this trial (n=60), which entailed a single intraoperative CT-abdomen and ipsilateral antegrade ureteroscopy when the surgeon felt stone treatment was visually complete. If residual fragments were identified, the surgeon continued nephroscopy to find and remove them; if not, the procedure was concluded. These patients were compared to a retrospective cohort (n=174) who underwent initial PCNL with post-operative imaging performed the following day.

RESULTS

The two cohorts had similar demographic properties and stone characteristics, and location of percutaneous access. In the prospective arm, 50% of intraoperative PCT scans identified residual fragments, prompting continuation of surgery to remove them. This cohort had significantly higher stone-free rate (82% vs. 36%, p<0.01), lower rate of planned reintervention (7% vs. 32%, p<0.01), lower rate of urgent presentation with ureteral obstruction (0% vs. 7%, p=0.04), lower total CT-based effective radiation dose (8.4 vs. 14.6 mSv, p<0.01), and shorter length of stay (2.3 vs. 3.5 days, p<0.01) when compared to the retrospective cohort that did not use intraoperative PCT.

CONCLUSIONS

Obtaining an intraoperative portable CT scan during PCNL can substantially improve perioperative outcomes. Further evaluation of this modality through a randomized-controlled trial is warranted.

Evaluation of the optimal duration for retrograde intrarenal stone surgery to prevent postoperative complications

OBJECTIVE

To evaluate retrograde intrarenal surgery (RIRS) outcomes and to determine the effect of operative time on complications of RIRS.

METHODS

Patients undergoing RIRS for renal stones were evaluated. These patients were divided into two groups according to the operation time (Group 1<60 minutes and Group 2>60 minutes). Peroperative outcomes such as fluoroscopy time, stone-free rates, complications and duration of hospitalization were compared.

RESULTS

Group 1 consisted of 264 patients and Group 2 consisted of 297 patients. SFR rates, duration of hospitalization, and postoperative urinary tract infection rates were similar in both groups. Fluoroscopy time was 7.8±7.3 (0-49) sec in group 1 and 13.1±9.8 (0-81) sec in group 2. Complications according to modified Clavien-Dindo classification system (MCDCS) were 13 and 32 patients (Grade 1), 31 and 63 patients (Grade 2), 1 and 1 patient (Grade 3) in group 1 and 2, respectively. There was statistical difference between the two groups in terms of duration of fluoroscopy time and the MCDCS. Although duration of hospitalization and UTI rates were higher in group 2, no statistical significance was observed among groups.

CONCLUSION

Limiting the operation time to 60 minutes in RIRS seems to be important in reducing postoperative complications.

Totally tubeless single access tract mini-percutaneous nephrolithotripsy in treatment of large burden > 2-cm and/or complex renal stones: a case series of 62 patients

Background

Limited literature has focused on the use of totally tubeless mini-percutaneous nephrolithotomy (PCNL) for the treatment of large renal stones. We present our findings of treating patients with large and/or complex renal stones using single renal access totally tubeless mini-PCNL.

Methods

From March 2018 to May 2021, 62 consecutive cases in which single tract totally tubeless mini-PCNL was used to treat complex renal stones were enrolled, all with calculi > 2 cm. All procedure of puncture and dilation were guided by fluoroscope. The complexity of stones was assessed according to the Guy’s Scoring System (GSS). The surgical duration, length of hospital stay, analgesia requirement, stone-free rate, and perioperative morbidity were assessed.

Results

The mean preoperative stone burden was 36.69 ± 19.76 mm (above 2 cm in all cases), mean surgical duration was 61.93 ± 40.84 min (range 15–180 min), and mean hematocrit reduction was 4.67 ± 2.83%. Postoperative Nalbuphine was used in 6 patients. The mean length of stay was 2.46 ± 1.19 days (range 2–8 days), and the postoperative stone-free rate was 83.9% (52/62), and 87.1% (54/62) after auxiliary ESWL. The overall complication rate was 14.5%, the majority of complications being postoperative transient fever.

Conclusion

For the treatment of large bursen > 2 cm and/or complex renal stones, totally tubeless single tract mini-PCNL ensures a feasible SFR, low morbidity and short hospital stay. According to the low complication rate in our study, the totally tubeless manner was not associated with an increased risk of postoperative morbidity, and patients benefited from decreased postoperative analgesics use.

One-stage efficacy of single tract minimally invasive ECIRS in the improved prone frog split-leg position for staghorn stones

OBJECTIVE

To explore the feasibility, safety, and effectiveness of single tract minimally invasive endoscopic combined intrarenal surgery (stmECIRS) in the improved prone frog split-leg position for staghorn stones.

METHOD

A total of 83 patients with staghorn stones were retrospectively reviewed between January 2018 and June 2021. According to surgical procedure and position, patients were divided into a group of single tract minimally invasive percutaneous nephroscopy (stmPNL) in the prone position and a group of stmECIRS in the improved prone frog split-leg position (turned to the prone position after preset the flexible ureteroscope sheath in lithotomy position, meanwhile, bend both hips and knees to be frog abduction). Demographic characteristics, laboratory tests, stone characters, surgical information, stone-free rate (SFR), and perioperative complications were observed and analyzed.

RESULTS

There were no significant differences in demographic characteristics, changes level of Scr and Hb, stone size, radiation density, length of hospital stay, and operation time between the two groups. One-stage SFR in the stmECIRS group was significantly higher than that in the stmPNL group (84.4% vs. 57.9%) (P = 0.007), only 2 patients required blood transfusion after surgery (P = 0.862), and other postoperative complications were not statistically significant (P = 0.345).

CONCLUSIONS

StmECIRS in improved prone frog split-leg position has a higher one-stage SFR than stmPNL for staghorn renal stones, and without complications increased, which is a safe, efficient and feasible treatment.

Flexible ureterorenoscopy (RIRS) vs. Mini- percutaneous nephrolithotomy (MINI-PCNL) for renal stones 20–30 mm a prospective randomized study

Background

To evaluate the safety and efficacy of mini percutaneous nephrolithotomy (mini PCNL) and retrograde intrarenal surgery (RIRS) in treatment of kidney stones 20–30 mm.

Methods

A prospective randomized study of 70 patients who presented to the urology department with calyceal or renal pelvic stone of 20–30 mm between September 2017 and September 2019. Patients were randomly divided into two groups, Group A (Mini PCNL) consists of 35 patients who were treated with mini PCNL and Group B (RIRS) consists of 35 patients who were Achieving success of the technique was considered when the patient is stone-free or has radiologically insignificant residual fragments < 4 mm.

Results

The demographic data in this study were comparable in both groups. The stone size was 20.43 ± 2.2 mm in group A & 20.5 ± 2.1 in group B, with no statistical significance. Meanwhile, the operative time in group A was 59.71 ± 19.44 min and in group B was 80.43 ± 14.79 min with statistical significance difference (p value < 0.001), while Fluoroscopy time had a mean of 8.11 ± 2.05 min in group A & 5.8 ± 1.98 min in group B with statistically significant diffrence (p value < 0.001). The stone free rate (SFR) was 88.6% in mini PCNL and 82.9% in RIRS with no statistically significant difference (p value: 0.5).

Conclusion

RIRS and mini PCNL can be an effective and alternative option for treatment of renal stones 2–3 cm. Both techniques have relatively similar SFR but RIRS showed more operative time, on contrary Mini-PCNL has more operative and postoperative complications. A multicenter studies with larger numbers of patients will be more effective to confirm these results.

Percutaneous laser nephrolithotripsy: is it here to stay? Results of a systematic review

PURPOSE OF REVIEW

PCNL (percutaneous nephrolithotomy) and its miniaturized variants are being widely employed in stone surgery, owing to their high-stone-free rates (SFRs) and efficacy for large (>20 mm) stones. With advances in laser technology, it has been readily utilized in PCNL, with the potential for lower complication rates at similar SFR. We aimed to perform a systematic literature review with a focus on recent prospective clinical data that compares laser PCNL to either nonlaser PCNL, different PCNL sizes or other current standards of care such as shockwave lithotripsy (ESWL) or flexible ureteroscopy (FURS).

RECENT FINDINGS

Of the 294 studies initially identified through database searching, nine papers published between 2019 and 2021 were included which compared laser PCNL (Standard PCNL in three, mini-PCNL in four, ultra-mini PCNL in one, micro-PCNL in one study) to other nonlaser lithotripsy, ESWL, FURS, and different PCNL sizes. Complications for laser PCNL ranged from bleeding (4.4%), perirenal haematoma (1.1%), fever (4.6%), ureteric/renal pelvic injury (2.3%), haematuria (2.7%), and infection (2.6%). The mean SFR for laser PCNL was 91.5% at 3 months.

SUMMARY

Percutaneous laser nephrolithotripsy is well tolerated and effective, with high-SFRs at 3 months and relatively low intraoperative and postoperative complication rates. Further research is required to assess the role of intraoperative techniques and suction to improve outcomes further.

Retrograde intrarenal surgery: laser showdown (Ho:YAG vs thulium fiber laser)

PURPOSE OF REVIEW

Retrograde intrarenal surgery (RIRS) has always been recommended for large stones > 20 mm, using the Ho:YAG laser. The introduction of a new technology in the urological market, the thulium fiber laser (TFL) has revolutionized the endourology world because of its characteristics and significantly shorter laser-on time (LOT) and operative time, without scarifying the champ vision. The aim of this review is to evaluate the most relevant findings of the last 2 years of each laser technology, confronting Ho:YAG vs TFL, analyzing who is more suitable for performing an efficient RIRS.

RECENT FINDINGS

Five full clinical trials using TFL for RIRS were found. Median LOT was between 2.8 and 34 min. All stones were similar in terms of stone volume, >500 mm3, and stone density, > 800 HU. Low complication rate, mostly Clavien-Dindo grade I and II and not related to the laser itself. One clinical trial only analyzed the efficacy of TFL for > 20 mm renal stones.

SUMMARY

Based on this review, TFL performs a more efficient RIRS than the Ho:YAG laser with similar safety.

Needle-perc-assisted endoscopic surgery for patients with complex renal stones: technique and outcomes

Our aim was to investigate the safety and efficacy of needle-perc-assisted percutaneous nephrolithotomy (PCNL) or retrograde intrarenal surgery (RIRS), namely, needle-perc-assisted endoscopic surgery (NAES), in a series of patients with large and/or complex renal stones. From May 2018 to August 2021, a total of 119 patients underwent NAES at our institute. Among them, 94 patients underwent needle-perc-assisted standard PCNL in prone position and 25 underwent needle-perc-assisted RIRS in the Galdakao-modified supine Valdivia position or prone split-leg position. Clinical factors including age, sex, medical history, and stone characteristics were collected. Intraoperative and postoperative outcomes were retrospectively evaluated. The patients' mean age ± standard deviation was 50.3 ± 14.3 years. The mean stone size was 7.6 ± 3.7 and 1.7 ± 0.8 cm for needle-perc-assisted PCNL and RIRS, respectively. Of the 119 patients, 51 had staghorn stones, 16 had solitary kidneys, 17 had a history of ipsilateral renal surgery, and 6 had calyceal diverticular stones. The mean operative time was 83.4 ± 25.9 min for needle-perc-assisted PCNL and 66.3 ± 21.8 min for needle-perc-assisted RIRS. The stone-free rate (SFR) for needle-perc-assisted PCNL was 77.7% after the first treatment and 88.3% after auxiliary treatments. The SFR for needle-perc-assisted RIRS was 88.0% and no auxiliary treatments were carried out in this group. Eleven (11.7%) patients who underwent needle-perc-assisted standard PCNL developed Clavien-Dindo grade I or II complications. Three (12.0%) patients who underwent needle-perc-assisted RIRS developed a fever (grade I). The overall complication rate for NAES was 11.8%, with no urosepsis, angioembolization, or other grade III to V complications. In conclusion, NAES is a safe and effective procedure for one-step complete resolution of large and/or complex renal stones with no additional procedure-related complications.

Mini percutaneous nephrolithotomy versus standard percutaneous nephrolithotomy for the management of renal stones over 2 cm: a systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

Standard percutaneous nephrolithotomy (sPCNL) is recommended for renal stones over 2cm. Mini percutaneous nephrolithotomy (mPCNL) has also emerged as a promising technique in this setting. We performed a systematic review and meta-analysis of randomized controlled trials (RCTs) comparing the safety and efficacy of sPCNL to mPCNL for the management of renal stones over 2cm.

EVIDENCE ACQUISITION

We systematically searched PubMed, Cochrane Library and Scopus databases until April 2021 and sources of grey literature for relevant RCTs. We performed a meta-analysis of odds ratios (ORs) to compare bleeding or other complications and stone-free rate (SFR) between sPCNL and mPCNL. Similarly, we undertook a metaanalysis of weighted mean differences for the mean operative and hospitalization time between the two techniques (PROSPERO: CRD42021241860).

EVIDENCE SYNTHESIS

Pooled data from 8 RCTs (2535 patients) were available for analysis. sPCNL was associated with a higher hemoglobin drop (0.59g/dl, 95%CI: 0.4-0.77, I2=93%), higher likelihood of postoperative blood transfusion (OR: 2.58, 95%CI: 1.03-6.45, I2=30%) and longer hospital stay (0.75 days, 95%CI: 0.45-1.05, I2=73%) compared to mPCNL. No significant differences were demonstrated in SFR (OR: 0.92, 95%CI: 0.74-1.16, I2=0%) and mean operative time (4.05 minutes, 95%CI: -9.45-1.37, I2=91%) after sPCNL versus mPCNL. Similarly, no significant differences were observed for postoperative fever, pain and Clavien-Dindo complications.

CONCLUSIONS

mPCNL represents a safe and effective technique and may be also recommended as a first-line treatment modality for well-selected patients with renal stones over 2cm. Still, further high-quality RCTs on the field are mandatory, since the overall level of evidence is low.

Super-mini percutaneous nephrolithotomy (SMP) vs retrograde intrarenal surgery (RIRS) in the management of renal calculi ≤ 2 cm: a propensity matched study

OBJECTIVE

To compare the effectiveness and safety of Super-Mini PCNL (SMP) and Retrograde Intrarenal Surgery (RIRS) in the management of renal calculi ≤ 2 cm.

PATIENTS AND METHODS

A prospective, inter-institutional, observational study of patients presenting with renal calculi ≤ 2 cm. Patients underwent either SMP (Group 1) or RIRS (Group 2) and were performed by 2 experienced high-volume surgeons.

RESULTS

Between September 2018 and April 2019, 593 patients underwent PCNL and 239 patients had RIRS in two tertiary centers. Among them, 149 patients were included for the final analysis after propensity-score matching out of which 75 patients underwent SMP in one center and 74 patients underwent RIRS in the other. The stone-free rate (SFR) was statistically significantly higher in Group 1 on POD-1 (98.66% vs. 89.19%; p = 0.015), and was still higher in Group 1 on POD-30 (98.66% vs. 93.24%, p = 0.092) SFR on both POD-1 and POD-30 for lower pole calculi was higher in Group 1 (100 vs. 82.61%, p = 0.047 and 100 vs 92.61% p = 0.171). The mean (SD) operative time was significantly shorter in Group 1 at 36.43 min (14.07) vs 51.15 (17.95) mins (p < 0.0001). The mean hemoglobin drop was significantly less in Group 1 (0.31 vs 0.53 gm%; p = 0.020). There were more Clavien-Dindo complications in Group 2 (p = 0.021). The mean VAS pain score was significantly less in Group 2 at 6 and 12 h postoperatively (2.52 vs 3.67, 1.85 vs 2.40, respectively: p < 0.0001), whereas the mean VAS pain score was significantly less in Group 1 at 24 h postoperatively (0.31 vs 1.01, p < 0.0001). The mean hospital stay was significantly shorter in Group 1 (28.37 vs 45.70 h; p < 0.0001).

CONCLUSION

SMP has significantly lower operative times, complication rates, shorter hospital stay, with higher stone-free rates compared to RIRS. SMP is associated with more early post-operative pain though.

Retrograde Intrarenal Surgery Versus Miniaturized Percutaneous Nephrolithotomy for Kidney Stones >1cm: A Systematic Review and Meta-analysis of Randomized Trials

CONTEXT

Although miniaturized percutaneous nephrolithotomy (mPCNL) and retrograde intrarenal surgery (RIRS) are both options for treating >1cm kidney stones, controversies exist on whether one is more effective and safer than the other.

OBJECTIVE

To systematically appraise randomized trials comparing the effectiveness and safety of mPCNL and RIRS for treating >1cm kidney stones.

EVIDENCE ACQUISITION

A systematic search on PubMed/Medline, Web of Science, Embase, and ClinicalTrials.gov was conducted in August 2020 following the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA). Randomized trials comparing mPCNL and RIRS for >1cm kidney stones, and reporting stone-free rate (SFR), hemoglobin drop, transfusion rate, length of hospital stay (LOS), and/or complications, were included.

EVIDENCE SYNTHESIS

Eight studies compared mPCNL and RIRS, but one was not included due to its high risk of bias. SFR was higher for mPCNL (RR: 1.06 [95% coefficient interval {CI}, 1.01-1.10], p=0.008). Hemoglobin drop was higher for mPCNL (mean difference [MD]: 0.35 [95% CI, 0.05-0.65] g/dl, p=0.02); however, transfusion rates were similar (p=0.44). Complication rate was similar between mPCNL and RIRS (p=0.39), and the LOS was higher for mPCNL (MD: 1.11 [95% CI, 0.06-2.16] d, p=0.04). A subgroup analysis of lower pole stones showed that SFR was higher for mPCNL (RR: 1.09 [95% CI, 1.00-1.19], p=0.05).

CONCLUSIONS

Both approaches are effective and safe. Among these approaches, mPCNL has a higher SFR than RIRS for overall >1cm renal and lower pole stones, but longer LOS, and a higher hemoglobin drop that does not translate into higher transfusion rates. Complications are comparable.

PATIENT SUMMARY

Randomized trials have evaluated whether miniaturized percutaneous nephrolithotomy (mPCNL) or retrograde intrarenal surgery is more effective and safer for treating >1cm stones. After comparing the stone-free rate, hemoglobin drop, transfusion rate, length of hospital stay, and complications between both the approaches, mPCNL was found to be slightly more effective, but both were equally safe.