The efficacy and safety of miniaturized percutaneous nephrolithotomy versus standard percutaneous nephrolithotomy: A systematic review and meta-analysis of randomized controlled trials

Incidence of metabolic syndrome in patients with unilateral or bilateral staghorn renal stones and its impact on percutaneous nephrolithotomy outcomes

BACKGROUND

To evaluate the incidence of metabolic syndrome (MetS) in patients with unilateral and bilateral staghorn calculi (SC) and evaluate the impact on the outcome of percutaneous nephrolithotomy (PCNL).

METHODS

The clinical data of patients who underwent PCNL for the treatment of SC between 2019 and 2022 were retrospectively reviewed. SC was divided into unilateral and bilateral. The incidence of MetS was compared between the patients with unilateral SC and the patients with bilateral SC, and the impact on the outcome of PCNL was assessed.

RESULTS

A total of 1778 patients underwent PCNL between 2019 and 2022. After screening computed tomography, 379 patients were confirmed to have SC, finally, leaving 310 patients with follow-up and complete data to be included in the study. Eighty-four had bilateral SC and 226 had unilateral SC. The patients with bilateral SC had a significantly higher body mass index and higher rates of complete staghorn stones and metabolic syndrome. Higher body mass index, hypertension, diabetes mellitus, hyperlipidaemia, and MetS were present in 62.58%, 44.84%, 21.94%, 60.65% and 27.42% of all patients, respectively. The number of MetS components remained significantly associated with bilateral SC. Specifically, when the number of MetS components increases from 0 to 3-4, the likelihood of developing bilateral staghorn calculi increases by 21.967 times. Eighty-five patients with MetS( +) had a higher rate of overall complications (number (N)(%), 29 (34.12) vs.33 (14.46), P < 0.001) and a comparable stone-free rate to 225 MetS(-) patients. Multivariable analysis confirmed that hyperlipidaemia (P = 0.044, odds ratio [OR] = 1.991, 95% confidence interval [CI] 1.020-3.888) and MetS (P = 0.005, OR = 2.427, 95% CI 1.316-4.477) were independent risk factors for overall complications.

CONCLUSIONS

MetS is correlated with the formation of bilateral SC and is the main predictor for complications of PCNL especially for low-grade complications (I-II).

Experience of Multiple Super-Selective Renal Angiographic Embolization (SRAE) After Minimally-Percutaneous Nephrolithotomy Haemorrhage: A Case Report

Minimally invasive percutaneous nephrolithotomy (mini-PCNL) maintains a stone clearance rate similar to standard PCNL while reducing blood loss. Bleeding is a complex and serious complication that can arise after PCNL surgery. Pseudoaneurysm (PA) is an uncommon type of delayed bleeding problem, which affects less than 1% of patients after PCNL. The most effective treatment for severe post-PCNL hemorrhage is super-selective renal angiographic embolization (SRAE), but it can fail in some patients and require additional surgical intervention. This report details the case of a male patient, 55 years old, who experienced severe bleeding four times and had three SRAE procedures and one laparoscopic procedure after PCNL. The presence of a renal artery pseudoaneurysm was not initially identified during the first two attempts of angiography due to arterial spasm and a small, undeveloped lesion. This case report is intended to enhance awareness of tiny pseudoaneurysms, emphasizing the importance of avoiding oversight to improve the success rate of embolization.

Reliability of nephrolithometric nomograms in patients treated with minimally invasive percutaneous nephrolithotomy: A precision study

Objectives

The study aimed to evaluate quality of nephrolithometric nomograms to predict stone-free rates (SFRs) and complication rates (CRs) in case of minimally invasive percutaneous nephrolithotomy (PNL). In the last decade, nomograms have been introduced to estimate the SFRs and CRs of PNL. However, no data are available regarding their reliability in case of utilization of miniaturized devices. Herein we present a prospective multicentric study to evaluate reliability of Guy's stone score (GSS), the stone size, tract length, obstruction, number of involved calyces, and essence of stone (S.T.O.N.E.) nephrolithometry score and Clinical Research Office of the Endourological Society (CROES) score in patients treated with minimally invasive PNL.

Methods

We evaluated SFRs and CRs of 222 adult patients treated with miniaturized PNL. Patients were considered stone-free if no residual fragments of any size at post-operative unenhanced computed tomography scan. Patients demographics, SFRs, and CRs were reported and analyzed. Performances of nomograms were evaluated with the area under the curve (AUC).

Results

We included 222 patients, the AUCs of GSS, CROES score, and S.T.O.N.E. nephrolithometry score were 0.69 (95% confidence interval [CI] 0.61-0.78), 0.64 (95% CI 0.56-0.73), and 0.62 (95% CI 0.52-0.71), respectively. Regarding SFRs, at multivariate binomial logistic regression, only the GSS had significance with an odds ratio of 0.53 (95% CI 0.31-0.95, p=0.04). We did not find significant correlation with complications, with only a trend for GSS.

Conclusion

This is the first study evaluating nomograms in miniaturized PNL. They still show good reliability; however, our data showed lower performances compared to standard PNL. We emphasize the need of further studies to confirm this trend. A dedicated nomogram for minimally invasive PNL may be necessary.

Comparative outcomes and cost of ambulatory PCNL in select kidney stone patients

Limited hospital resources and access to care during the COVID-19 pandemic led us to implement a quality-improvement study investigating the feasibility, safety, and costs of same-day discharge after PCNL. The outcomes of 53 consecutive first-look PCNL patients included in a same-day discharge protocol during COVID-19 were compared to 54 first-look PCNL patients admitted for overnight observation. Control group had a similar comorbidity profile. Demographics, operative details, 30 day outcomes and readmissions, complications, and cost were compared between the two groups. Same-day discharge and one-day admission post-PCNL patients did not have significantly different baseline characteristics. The study group were more likely to have mini-PCNL (81% vs 50%, p < 0.01). Operative characteristics including median pre-operative stone burden (1.4 vs 1.7 cm3, p = 0.47) and post-operative stone burden (0.14 vs 0.18 cm3, p = 0.061) were similar between the two groups. Clavien-Dindo complication rates were lower in the study group compared to controls (0 vs 7%, p = 0.045). Readmission rates (2 vs 4%, p = 0.569) and ED visits (4 vs 6%, p = 0.662) were similar between the two groups. Total cost ($6,648.92 vs $9,466.07, p < 0.01) was significantly lower and operating margin ($4,475.96 vs $1,742.16, p < 0.01) was significantly higher for the same-day discharge group. Percutaneous nephrolithotomy may be performed in select patients without an increase in short-term complications, ED visits, or readmissions. Patients undergoing mini-PCNL are particularly amenable to same-day discharge, however, standard PCNL patients should not be excluded from consideration. Avoiding overnight admission decreases total cost and increased hospital operating margin.

International Alliance of Urolithiasis (IAU) Guideline on percutaneous nephrolithotomy

The International Alliance of Urolithiasis (IAU) would like to release the latest guideline on percutaneous nephrolithotomy (PCNL) and to provide a clinical framework for surgeons performing PCNLs. These recommendations were collected and appraised from a systematic review and assessment of the literature covering all aspects of PCNLs from the PubMed database between January 1, 1976, and July 31, 2021. Each generated recommendation was graded using a modified GRADE methodology. The quality of the evidence was graded using a classification system modified from the Oxford Center for Evidence-Based Medicine Levels of Evidence. Forty-seven recommendations were summarized and graded, which covered the following issues, indications and contraindications, stone complexity evaluation, preoperative imaging, antibiotic strategy, management of antithrombotic therapy, anesthesia, position, puncture, tracts, dilation, lithotripsy, intraoperative evaluation of residual stones, exit strategy, postoperative imaging and stone-free status evaluation, complications. The present guideline on PCNL was the first in the IAU series of urolithiasis management guidelines. The recommendations, tips and tricks across the PCNL procedures would provide adequate guidance for urologists performing PCNLs to ensure safety and efficiency in PCNLs.

Mini Versus Standard Percutaneous Nephrolithotomy for the Management of Renal Stone Disease: Systematic Review and Meta-analysis of Randomized Controlled Trials

CONTEXT

Mini percutaneous nephrolithotomy (mPNL) involves the creation of a smaller access tract compared with standard PNL (sPNL). Smaller tract sizes could lead to decreased blood loss, pain, and need for blood transfusion. Previous studies on this topic have reported variable findings and were of poor quality.

OBJECTIVE

To compare the safety and efficacy of mPNL with those of sPNL for the management of patients with renal stone disease by conducting a systematic review and meta-analysis.

EVIDENCE ACQUISITION

Systematic literature search was performed to identify relevant randomized controlled trials (RCTs) for the review. The primary outcomes for the study were stone-free rate (SFR) and blood transfusion rate. The secondary outcomes were complication rates, fever, fall in hemoglobin, operative time, length of stay (LOS), need for auxiliary procedure, and visual analog scale (VAS) score at 24 h. We followed Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines, and the study protocol was registered with PROSPERO in priori (CRD42021252444).

EVIDENCE SYNTHESIS

In this review, 16 RCTs with 3961 patients were included. SFR was comparable between the two groups (risk ratio [RR] 1.01 [0.99, 1.04], p = 0.30), whereas the need for transfusion was lower with mPNL (RR 0.54 [0.37, 0.78], p = 0.001). Fall in hemoglobin (mean difference [MD] -0.67 [-0.93, -0.41], p = 0.000) and LOS (MD -0.59 [-0.81, -0.37], p = 0.000) were shorter with mPNL. Operative time was significantly shorter with sPNL (MD 8.28 [3.96, 12.59], p = 0.000). Complications were lower with mPNL (RR 0.89 [0.79, 0.97], p = 0.01). The need for auxiliary procedures (RR 0.77 [0.58, 1.03], p = 0.08) and VAS at 24 h (MD -0.79 [-1.63, 0.05], p = 0.06) were similar in the two groups.

CONCLUSIONS

Mini PNL has similar efficacy to sPNL in terms of SFRs. However, mPNL has a superior safety profile with fewer overall complications and a reduced need for blood transfusion.

PATIENT SUMMARY

In this study, we conducted a meta-analysis comparing mini and standard percutaneous nephrolithotomy (PNL) for the management of patients with renal stone disease. We showed that mini and standard PNL are associated with similar stone-free rates. Overall complications and the need for blood transfusion were lower with mini PNL.

The Safety and Efficacy of Endoscopic Combined Intrarenal Surgery (ECIRS) versus Percutaneous Nephrolithotomy (PCNL): A Systematic Review and Meta-Analysis

Purpose

Our aim is to evaluate the safety and efficacy of endoscopic combined intrarenal surgery compared to percutaneous nephrolithotomy to guide practitioners and inform guidelines.

Materials and Methods

A detailed database search was performed in PubMed, OVID, Scopus, and Web of Science in October 2021 to identify articles pertaining to ECIRS published between 2001 and 2021.

Results

Four nonrandomized comparative studies and one RCT were identified, yielding five studies with a total of 546 patients (ECIRS/mini-ECIRS, n = 277; PCNL/mini-PCNL, n = 269). Subjects in these five studies met the predefined inclusion criteria established by two reviewers (J.E.A. and R.L.S.) and were therefore eligible for analysis. The results demonstrated that ECIRS was associated with a higher SFR (OR: 4.20; 95% CI: 2.79, 6.33; p < 0.00001), fewer complications (OR: 0.63; 95% CI: 0.41, 0.97; p=0.04), and a shorter hospital stay (WMD: −1.27; 95% CI: −1.55, −0.98; p < 0.00001) when compared to PCNL. There were no statistically significant differences in blood transfusions (OR: 0.45; 95% CI: 0.12, 1.68; p=0.24), operative time (SMD: −1.05; 95% CI: −2.42, 0.31; p=0.13), or blood loss (SMD: −1.10; 95% CI: −2.46, 0.26; p=0.11) between ECIRS and PCNL.

Conclusions

ECIRS may be a more suitable approach for the surgical management of large and complex kidney stones currently indicating PCNL due to its superior efficacy with comparable surgical time and complication rate, though it is thought that a lack of resources and properly trained personnel may preclude ECIRS from becoming the standard. It is our impression that ECIRS may become the preferred technique in the endourologic community corresponding to the evolutionary sequence of percutaneous stone surgery.

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.

Acute pulmonary embolism and severe post thrombolysis renal bleeding, two deadly complications following mini-percutaneous nephrolithotomy: a rare case report

BACKGROUND

Acute pulmonary embolism and severe renal bleeding are two lethal postoperative complications, but there has been no report that involves both of them after mini-percutaneous nephrolithotomy.

CASE PRESENTATION

A 62-year-old woman was admitted to our hospital with extremely severe hydronephrosis and multiple right renal calculi. After thorough examination, she received prone-position mini-percutaneous nephrolithotomy under spinal anaesthesia. Three days postoperatively, the patient complained of chest pain and dyspnea. Computed tomography pulmonary angiogram (CTPA) showed multiple embolisms in the left pulmonary artery and its branches. Symptoms were relieved after anticoagulant and thrombolysis therapy. On the 6th postoperative day, the patient developed shortness of breath, computed tomography angiography (CTA) showed massive hemorrhage in the right kidney, diffused contrast medium in the middle and lower part of the right kidney was seen during digital substraction angiography (DSA). Superselective right renal artery embolization (SRAE) was then applied using coil to occlude the responsible artery. The patient generally recovered under conscientious care and was approved to be discharged 26 days postoperatively.

CONCLUSIONS

This is the first case that involved both acute pulmonary embolism and severe post thrombolysis renal bleeding. The importance of D-dimer in the prediction and early detection of pulmonary embolism should be noted. For post thrombolysis renal bleeding, SRAE is considered as a reliable treatment.

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.

Does previous standard percutaneous nephrolithotomy impair retrograde intrarenal surgery outcomes?

PURPOSE

The objective of this study is to evaluate the impact of a previous standard percutaneous nephrolithotomy (PCNL) on the outcomes of retrograde intrarenal surgery (RIRS).

MATERIALS AND METHODS

Outcomes of RIRS performed from January 2017 to January 2020 in adult patients with residual stone fragments ≤20mm after a standard PCNL (Post-PCNL) and symptomatic adult patients with kidney stones ≤20mm (Control) were prospectively studied. Stone-free rate (SFR) was evaluated on a postoperative day 90 non-contrast computed tomography. Surgical complications based on Clavien-Dindo classification during the 90 days of follow-up were recorded.

RESULTS

Outcomes of 55 patients and 57 renal units of the post-PCNL group were compared to 92 patients and 115 renal units of the control group. SFR was lower in post-PCNL group than in control (28/57, 49.1% vs. 86/115, 74.8%, p < 0.001). Overall complications were more frequent in post-PCNL group (p=0.004). Infundibula strictures were identified and incised with laser in 15/57 (26.3%) renal units of the post-PCNL group. Thirteen renal units had infundibulum stricture at the site of previous percutaneous tract (13/15; 86.7%, p=0.004) and one renal unit had three infundibula strictures. Postoperative complications were not affected by the treatment of infundibula strictures (p=0.198).

CONCLUSIONS

Previous standard PCNL significantly impairs the outcomes of RIRS. Infundibula strictures can be found in 26.3% of the patients with residual stone fragments after standard PCNL for large burden kidney stones. The main site of infundibulum stricture after standard PCNL is the infundibulum of the entry calyx.

Providing Several Skills to Treat Complex Infectious Stones of Solitary Kidney in a Patient Failed to Undergo Percutaneous Nephrolithotomy: A Case Report

Conservative treatment is closely associated with renal deterioration for patients with renal staghorn stones. It is well-recognized that percutaneous nephrolithotomy (PCNL) is recommended as the first-line treatment of renal stones larger than 2 cm due to its higher stone clearance and cost-effectiveness when compared with other treatment alternatives, such as shockwave lithotripsy and flexible ureteroscopy (FURS). Besides, our findings indicated that miniaturized PCNL could be served as an alternative to PCNL with a higher stone-free rate and a lower hemorrhage risk. Despite the higher cost-effectiveness of PCNL, the management of staghorn stones are still controversial in some special situations, such as a solitary kidney. Herein, we present a case with complex infectious stones of a right-sided solitary kidney, complaining of persistent pain in the right waist. The rarity of this case is that it is difficult to encounter these cotton-like staghorn stones which are clinically resistant to holmium laser lithotripsy, and the particularity is that the patient with solitary kidney failed to undergo PCNL. We found that the combination of intermittently high-frequency oscillation and flexible ureteroscopy forceps might contribute to treat the complex infectious stones in a patient with solitary kidney. Our surgical experience might be beneficial to such patients undergoing flexible ureteroscopy in clinical practice.

Study on Clinical Application of Different Ultrasound-Guided Planar Techniques in Minimally Invasive Percutaneous Nephrolithotomy

Objective. The objective is to explore the clinical application value of ultrasound long- and short-axis planar technology in real-time guided puncture in minimally invasive percutaneous nephrology. Methods. The clinical data of 80 patients undergoing real-time ultrasound-guided minimally invasive percutaneous nephrolithotomy from September 2018 to October 2019 were analyzed. The patients were randomly divided into 2 groups with different ultrasound-guided puncture techniques, long-axis in-plane technique and short-axis out-of-plane technique. Results. Minimally invasive percutaneous nephrolithotomies under real-time ultrasound guidance were successfully completed in both groups of patients. The success rate of the first puncture in the short-axis out-of-plane group was significantly higher than that in the long-axis in-plane group, and the differences were statistically significant (P <.05); the total puncture time in the short-axis out-of-plane group was significantly less than the long-axis in-plane group, and the differences were statistical significance (P <.05); there was no significant difference in the single-stage stone removal rate, total percutaneous renal channels, total hospital stay, and rate of complications by the Clavien classification between the 2 groups (P > .05). Conclusion. Ultrasound long-axis and short-axis planar technologies can achieve good clinical application results in real-time guided puncture to establish percutaneous renal channels during minimally invasive percutaneous nephrolithotomy. Compared with the long-axis in-plane technique, the short-axis out-of-plane technique can shorten the puncture time and improve the success rate of the first puncture.

Definition and Unfavorable Risk Factors of Trifecta in Mini-Percutaneous Nephrolithotomy

Objectives: In performing mini-percutaneous nephrolithotomy (PCNL), we aimed at achieving the trifecta of stone-free status and no complications in a single treatment session. We analyzed our experience to determine negative predictors for achieving these three-fold goals. Patients and Methods: The data of all consecutive patients who underwent tubeless mini-PCNL between July 2015 and March 2020 in two hospitals were retrospectively reviewed. Stone-free was defined as no residual stones. Complications were recorded and graded according to modified Clavien classification. Patients were divided into two groups according to the outcome (trifecta and non-trifecta). Factors affecting the outcome were compared between both groups by using univariate and multivariate analyses to detect independent unfavorable risk factors. Results: The study included 944 patients with mean age 40.2 years (standard deviation: 13.6). The stone-free rate after one session of mini-PCNL was 90.7%. Auxiliary procedures were needed in 14 patients (1.5%). Complications were observed in 76 patients (8.1%). Trifecta was achieved in 792 patients (84%). Independent unfavorable risk factors in multivariate analysis were number of caliceal groups affected by the stones (relative risks were 1.95 to 2.27 and 5.7 for one, two, and three caliceal groups respectively) and number of percutaneous tracts (relative risk was 2.2). Stone size and complexity were not significant predictors of missing trifecta in multivariate analysis. Conclusions: Mini-PCNL can achieve a high rate of trifecta (84%) for different stone sizes and complexities. Stones distribution in multiple caliceal groups and multiple tracts are the independent unfavorable risk factor.

Precision Stone Surgery: Current Status of Miniaturized Percutaneous Nephrolithotomy

PURPOSE OF REVIEW

Innovations in lasers and surgical technology have led to a renewed interest in the miniaturization of percutaneous nephrolithotomy (PCNL). We review the different approaches and evidence on the efficacy of mini-PCNL.

RECENT FINDINGS

Mini-PCNL encompasses a range of techniques using tract sizes from 4.8 to 22 F to treat renal stones. The most common device uses irrigation to passively extract stones out of the sheath. Super-mini-PCNL incorporates active suction. Ultra- and micro-techniques reduce the tract to smaller diameters. Laser fragmentation is the main lithotripsy modality. Studies demonstrate an association with reduced complications, hospital stay, and increased tubeless rate. Drawbacks include longer operative times while stone-free rates for larger stones may be sub-optimal. Mini-PCNL has advantages of less trauma and the avoidance of nephrostomy tubes. Ambulatory surgery is feasible in select patients. Advances in laser lithotripsy and active suction have the potential to improve stone clearance and treat larger stones.

Comparison of standard- and mini-percutaneous nephrolithotomy for staghorn stones

Objectives: To compare the outcomes of standard- and mini-percutaneous nephrolithotomy (PCNL) for the treatment of staghorn stones.

Patients and Methods: The data of consecutive adult patients who underwent PCNL for the treatment of staghorn stones, between July 2015 and December 2019 from three hospitals, were retrospectively reviewed. All cases were performed in a prone position under fluoroscopic guidance. The nephrostomy tracts were dilatated to 30 F in standard-PCNL and to 18–20 F in mini-PCNL. Stones were fragmented with pneumatic lithotripsy in both groups. Fragments were removed with forceps in the standard-PCNL, while they were evacuated through the sheath using the vacuum clearance effect in mini-PCNL. A ureteric stent was inserted after mini-PCNL, while a nephrostomy tube was inserted after standard-PCNL.

Results: The study included 153 patients; 70 underwent standard-PCNL and 83 underwent mini-PCNL. The stone-free rates of PCNL monotherapy were comparable for both groups (83% for mini-PCNL and 88.6% for standard-PCNL, P = 0.339). The incidence (12% vs 24.3%, P = 0.048) and severity of complications were significantly lesser with mini-PCNL (P = 0.031). Standard-PCNL was associated with increased rate of blood transfusion (12.9% vs 2.4%, P = 0.013) and a significant decrease in haemoglobin (P = 0.018). Hospital stay was significantly longer for standard-PCNL than mini-PCNL (median stay of 6 vs 3 days, P < 0.001).

Conclusions: The efficacy of mini-PCNL was comparable to standard-PCNL in the treatment of staghorn stones. The advantages of mini-PCNL included a lesser incidence and severity of complications, and shorter hospital stay.

Efficacy and safety of modified tract dilation technique using simultaneous pulling of proximal and distal ends of a guidewire for percutaneous nephrolithotomy in modified supine position

Purpose

Recently, the needs for supine percutaneous nephrolithotomy (PCNL) have become more increased because of an easy approach for endoscopic combined intrarenal surgery. However, making a nephrostomy tract during supine PCNL is more difficult than prone position due to movable kidney. To overcome this limitation, we used a modified nephrostomy tract dilation (MTD) technique using guidewire traction.

Materials and Methods

From January 2014 to June 2019, a total of 259 patients underwent PCNL in the modified supine position. Among them, the MTD technique was performed in 171 patients. For the MTD technique, two hydrophilic guidewires were passed from the nephrostomy tract and brought out through the urethra, then both proximal and distal ends were contralaterally pulled with tension for the easy placement of a fascia-cutting needle and a balloon catheter. We analyzed the efficacy of this technique in comparison with the conventional method.

Results

Intraoperative radiation exposure time (RET) (68.87 vs. 212.11 s) and hospital stay (5.90 vs. 6.74 days) were significantly shorter, while the success rate (77.2% vs. 63.6%) was significantly higher in the MTD group. Multivariate analysis showed that only the maximal stone diameter (odds ratio [OR], 1.928; 95% confidence interval [CI], 1.314–2.828; p=0.001) and MTD technique (OR, 0.017; 95% CI, 0.007–0.040; p<0.001) were independent factors for predicting short RET (<120 s).

Conclusions

This study demonstrated that MTD technique can be effectively and safely performed in modified supine position PCNL, and it can be helpful in reducing RET and enhancing success rates.

Minimally Invasive Percutaneous Nephrolithotomy: Initial North American Experience

Introduction and Objectives: The goal of this study is to evaluate the outcomes in a cohort of patients who underwent minimally invasive percutaneous nephrolithotomy (MIP) at a single institution from 2017 to 2019. Methods: Sixty patients at a single institution with two different surgeons underwent MIP from 2017 to 2019. The MIP technique uses a proprietary nephroscope with a "vacuum" technique for stone evacuation. Patients were identified who had postoperative CT scan imaging available for direct review. A prospectively maintained database was queried along with retrospective chart review to evaluate the stone-free rate defined as no stones on CT imaging. Preoperative, intraoperative, and postoperative variables were analyzed including initial stone size, access type (fluoroscopic vs ultrasonic), access location, operative positioning (supine vs prone), operative time, and 60-day complications. Results: Forty-six of 60 patients had CT imaging postoperatively that were reviewable. Of these, 43% (n = 20) were stone free as defined by no identifiable fragments seen, 11% (n = 5) had residual fragments 0 to 2 mm, 7% (n = 3) had residual fragments 2 to 4 mm, and 39% (n = 18) had residual fragments >4 mm. Mean initial stone size was 21 mm (1.9-84 mm). Sixty percent (n = 28) of the patients were discharged the same day as surgery. Fifty-one percent (n = 24) of access was achieved through ultrasound alone. Seventeen percent of patients (n = 8) had a complication within 30 days of surgery. All complications were Clavien III or lower with unplanned return to operating room rate of 2% (n = 1). Conclusions: We present North America's first single institution analysis of MIP cases with acceptable outcomes comparable with both retrograde intrarenal surgery and standard percutaneous nephrolithotomy. The exact role of MIP in renal stone disease needs to be determined by future studies that critically assess their outcomes.

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.

Comparison of intrarenal pelvic pressure and postoperative fever between standard- and mini-tract percutaneous nephrolithotomy: a systematic review and meta-analysis of randomized controlled trials

Background

High intrarenal pelvic pressure (IPP) induces systemic absorption of irrigation fluid containing bacteria or endotoxins, which is associated with postoperative fever (POF) and even urosepsis. The emphasis of this meta-analysis lies in comparison of IPP and POF between mini-tract percutaneous nephrolithotomy (MPCNL) and standard-tract percutaneous nephrolithotomy (SPCNL).

Methods

Eligible randomized controlled trials (RCTs) were identified from electronic databases from inception to November 2019. Studies selection, quality assessment, data extraction and analysis were accomplished by two independent reviewers using Cochrane Collaboration’s tools.

Results

Patients in the MPCNL group experienced higher IPP compared to SPCNL group [mean difference (MD): 8.31, 95% confidence interval (CI): 3.67–12.96, P=0.0005] with highly between-study heterogeneity (P=0.001, I²=85%). Notably, the IPP was higher in MPCNL group in different stages of the procedure including introduction, fragmentation and end. However, only two trials were available for pooled analysis. Additionally, the risk of POF in MPCNL was 2.43 times higher than that in SPCNL [odds ratio (OR): 2.43, 95% CI: 1.39–4.27, P=0.002] with no significant between-study heterogeneity (P=0.83, I²=0%). The two procedures was comparable on stone-free rate (SFR) (OR: 1.06, 95% CI: 0.61–1.86, P=0.83) and operation time (MD: 5.69, 95% CI: −4.54 to 15.91, P=0.28).

Conclusions

Current evidence indicates that MPCNL is an effective alternative to SPCNL with comparable SFR. IPP and POF is significantly higher during MPCNL compared to SPCNL. Intraoperative detection of IPP is of great significance for ensuring safety and reducing postoperative complications, especially for patients with MPCNL and the duration of stone fragmentation. Further large well-designed trials are warranted to confirm our findings.