Mini vs standard percutaneous nephrolithotomy for renal stones: a comparative study

Flexible ureteroscopy with novel flexible ureteral access sheath versus mini-percutaneous nephrolithotomy for treatment of 2-3 cm renal stones

OBJECTIVES

To assess and compare the effectiveness and safety of flexible ureteroscopy (f-URS) with a novel flexible ureteral access sheath (f-UAS) versus mini-percutaneous nephrolithotripsy (mini-PCNL) in treating 2-3 cm renal stones.

METHODS

Retrospectively analyzed consecutive cases that underwent f-URS with f-UAS (12/14 Fr) from January 29, 2022, to November 30, 2022. Consecutive cases that underwent mini-PCNL (18 Fr) from June 5, 2021, to January 26, 2022, were selected as controls. The f-UAS is a novel device with a 10 cm anterior tip that passively bends along with the f-URS to enter the renal calyx. We analyzed demographic characteristics, stone parameters, operative time, stone-free rates (SFR), hospitalization time, and complication.

RESULTS

A total of 96 consecutive cases that underwent f-URS with f-UAS and 96 consecutive cases that underwent mini-PCNL were included in the study. There were no significant differences between the two groups in terms of operative time (p = 0.06), stone volume clearance (p = 0.533) and complete SFR (p = 0.266) on the first postoperative day or residual Stone after 1 month (p = 0.407). We observed a significantly shorter postoperative hospital stay (1.4 days vs. 2.1 days; p < 0.001) and a lower decrease in hemoglobin levels (0.39 g/dL vs. 0.68 g/dL; p < 0.001) in the f-UAS group. The mini-PCNL group had a significantly higher overall complication rate (13.5%) compared with the f-UAS group (5.2%; p = 0.048).

CONCLUSIONS

In the treatment of 2-3 cm renal stones, f-URS with a novel f-UAS may provide a superior alternative to mini-PCNL, potentially challenging its established status.

The Outcome of the Miniaturized Percutaneous Nephrolithotomy in Lateral Position with Guidance of Non-Rotational C-Arm

Objective

Evaluation of the outcome of the miniaturized percutaneous nephrolithotomy in the treatment of nephrolithiasis with a lateral position based on the principle of a right triangle under the guidance of a C-Arm without contrast fluid.

Materials and Methods

Sixty-nine cases of Mini-PCNL with the assistance of a vacuum-assisted sheath in the lateral position were performed at Central Hospital from March 2021 to August 2022. Percutaneous renal access was under the guidance of a non-rotational C-arm without contrast medium, and we determined the puncture location and depth of the needle based on the principle of right triangles.

Results

The median age was 51.6 ± 12.5 years, and males accounted for 68.1% of the cases. 60.9% of all patients had normal weight. The median stone surface area was 361.1mm2, and 59.4% of all cases were graded as 2 regarding Guy's stone score. The successful renal access rate was 100%. The tunnel access from the middle and lower calyx accounted for 94.2%. The median access duration, fluoroscopy duration, and hospital length of stay were 271.7 seconds, 14.79 seconds, and 6.3 days, respectively. The complete stone clearance rate was 78.3%. Bleeding complications occurred in 2 patients without mortality. Three patients required an additional procedure.

Conclusion

The puncture technique into the renal calyxes based on the principle of the right triangle under the guidance of a non-rotational C-Arm without contrast medium in PCNL is a fast, exact, and safe technique.

Mini-percutaneous nephrolithotomy: Is smaller better for kidney stones in patients with neurogenic bladder?

INTRODUCTION

Patients with neurologic bladder are at an increased risk for urolithiasis, and currently, data on mini-percutaneous nephrolithotomy in this population are limited. Our objective was to compare mini (15F)-percutaneous nephrolithotomy, standard (24F)-PCNL and flexible ureteroscopy in terms of efficacy and safety in treatment of kidney stones in patients with neurogenic lower urinary tract dysfunction (NLUTD).

METHODS

We conducted a retrospective monocentric study in our neuro-urological referral centre. All consecutive patients with NLUTD and a cumulative size of renal calculi greater than 15mm or 10mm in the lower calyx, who had extraction surgery between 2005 and 2020, were included. The primary endpoint was the one-session stone-free rate (SFR) at 3 months on a CT scan. The secondary endpoints were complication (Clavien-Dindo grading system), operative time, blood loss and length of hospital stay.

RESULTS

We performed 76 standard PCNL (sPCNL), 46 flexible ureteroscopy lithotripsy (fURL) and 25 miniaturized PCNL (mPCNL). The one-session SFR was 37.5% for the mPCNL group, 38.2% for the sPCNL group and 37% for the fURL group with no significant difference between the three procedures (P=0.99). Early complications, blood loss and transfusion rates were lower in the mPCNL group than in the sPCNL group (P=0.047) and comparable to fURL group. The final SFRs after a second intervention for mPCNL, sPCNL and fURL were 48%, 61.8% and 63%, respectively (P=0.67).

CONCLUSION

The efficacy of mPCNL in patients with NLUTD was not different from other techniques, but a significantly lower rate of complications than sPCNL was observed.

LEVEL OF PROOF

3.

Miniaturizing the approach to upper tract renal calculi: Is smaller always better? A narrative review

Newer modalities for treating upper tract urinary stones focus on maintaining and improving outcomes, reducing complications, and optimizing patient care. This narrative review aims to outline novel miniaturized endourological innovations for managing upper tract calculi.

Comparison Between Mini-Percutaneous Nephrolithotomy and Standard Percutaneous Nephrolithotomy in Management of Large Renal Stones: A Randomized, Controlled Clinical Trial

Objectives: The aim of this study was to compare mini-percutaneous nephrolithotomy (PNL) and standard PNL in management of renal stones (20-40 mm) with regard to the operative time, fluoroscopy time, blood loss, stone-free rate, and postoperative complications. Subjects and Methods: This prospective, randomized comparative study was carried out on 93 patients divided into two groups: Group A included 44 patients who underwent standard PNL, whereas Group B included 49 patients who underwent mini-PNL. Results: Standard PNL showed shorter operative time, yet longer hospitalization and nephrostomy and catheterization time. The mean drop in hemoglobin level was significantly lower in the mini-PNL group. In the 1st postoperative week, the stone-free rate was higher in the standard PNL group, but this was statistically insignificant. However, 4 weeks postoperatively, the stone-free rate was significantly higher in Group A. Postoperative pain and the need for postoperative analgesia were significantly higher in standard PNL patients. Conclusions: Standard PNL achieved a higher stone-free rate and shorter operative time, while mini-PNL had the advantage of shorter hospitalization time and lower incidence of pain and postoperative complications.

Vacuum-assisted access sheath in supine mini-percutaneous nephrolithotomy (mini-PCNL)

INTRODUCTION

The vacuum-assisted access sheath is a new device for the treatment of kidney stones with percutaneous nephrolithotomy (PCNL).

OBJECTIVE

Our aim was to compare the stone-free rate (SFR) and complications between standard mini percutaneous nephrolithotomy (Mini-PCNL) and vacuum-assisted PCNL (Va-PCNL).

METHODS

Retrospective study of patients undergoing Mini-PCNL and Va-PCNL from January 2018 to June 2022. Va-PCNL was performed with a disposable sheath (ClearPetra®) with continuous high-flow irrigation and vacuum fluid dynamics for easier stone fragment removal. Baseline patient characteristics, surgical outcomes, perioperative and postoperative data were collected. We compared SFR and complications.

RESULTS

A total of 136 patients were identified, 57 (41,9%) underwent Va-PCNL and 79 (58,15%) Mini-PCNL. Mean operative time was significantly shorter in the Va-PCNL group (95 min.) than in Mini-PCNL (146 min; P = ,001) group. The tubeless technique was performed more frequently in Va-PCNL group (61,4% vs. 34,2%; P = ,002). We did not observe any differences in postoperative complications. The mean hospital stay was significantly lower in Va-PCNL with 1,7 ± 1,9 days per patient compared with 2,7 ± 1,5 days in the Mini-PCNL group (P = ,001). There were no differences in SFR at 3 months between Va-PCNL (71,9%) and Mini-PCNL (71,8%; P =v ,848).

CONCLUSION

Patients treated with Va-PCNL had comparable results to Mini-PCNL, showing equal SFR with similar infectious complications rates. Potential benefits of Va-PCNL include shorter operative time and postoperative stay.

Efficacy and safety of minimally invasive percutaneous nephrolithotomy versus retrograde intrarenal surgery in the treatment of upper urinary tract stones (> 1 cm): a systematic review and meta-analysis of 18 randomized controlled trials

BACKGROUND

The advantages and disadvantages of retrograde intrarenal surgery (RIRS) and minimally invasive percutaneous nephrolithotomy (mPCNL) for treatment of upper urinary tract calculi have not been conclusively determined.

METHODS

In this meta-analysis, We comprehensively evaluated the performance of the two surgical approaches in treatment of upper urinary calculi. We searched the Pubmed, Embase, Cochrane and Web of science databases for randomized controlled trial (RCT) articles on RIRS and mPCNL upto December 2022. Data were extracted by two independent reviewers and subjected to the meta-analysis using the Stata 15.1 software (StataSE, USA).

RESULTS

A total of 18 eligible RCTs involving 1733 patients were included in this study. The meta-analysis revealed that mPCNL of 1-2 cm or 2-3 cm stones had a higher stone clearance rate (RR:1.08, 95%CI (1.03, 1.14), p = 0.002) and shorter operation time (WMD : -10.85 min, 95%CI (-16.76, -4.94), p<0.001). However, it was associated with more hospital stay time (WMD :1.01 day, 95%CI(0.53, 1.5), p<0.001), hemoglobin drops (WMD :0.27 g/dl, 95%CI (0.14, 0.41), p<0.001), blood transfusion rate (RR:5.04, 95%CI(1.62, 15.65), p = 0.005), pain visual analogue score (WMD:0.75, 95%CI (0.04, 1.46), p = 0.037), hospital costs (SMD :-0.97, 95%CI (-1.19, -0.76), p<0.001) and major complications (RR:1.89, 95%CI(1.01, 3.53), p = 0.045).

CONCLUSION

Therefore, in terms of surgical effects and operation time, mPCNL is superior to RIRS, but is inferior with regards to other perioperative parameters. These factors should be fully considered in clinical decision making.

Which position is more advantageous for percutaneous nephrolithotomy: supine or prone?

Percutaneous nephrolithotomy (PNL) can be performed in a number of different positions. Our aim was to evaluate the convenience and advantages of the supine position following the transition from the prone to the supine position. 94 patients undergoing supine PNL (Group-1) and 93 patients undergoing prone PNL (Group-2) were retrospectively reviewed and included in the study. Patients who underwent mini-PNL (mPNL) were selected from Group-1 and Group-2 and divided into Group-1A supine mPNL patients (77) and Group-2A prone mPNL patients (53). Demographic characteristics, operative data and post-operative parameters were compared between these groups. The operation time was 74.4 ± 21.9 min in Group-1A and 79.2 ± 19.8 min in Group-2A (p = 0.076). The median value of fluoroscopy time was 30 s in Group-1A and 40 s in Group-2A (p = 0.003). In Group-1A, 59 patients had no intraoperative double-J stent (DJS) insertion and 18 patients had DJS insertion, while in Group-2A, 24 patients had no DJS insertion and 29 patients had DJS insertion (p < 0.001). MPNL was performed in 81.9% of patients in the supine position and 57% in the prone position. This difference was statistically significant (p < 0.001). No significant difference was found with regard to the success rate and the complications of mPNL. Fluoroscopy time is shorter in the supine position. Moreover, the insertion rates of DJS are low. With increasing experience, we have found that our standard PNL (sPNL) rate is gradually decreasing and more mPNL is being performed.

Antegrade Percutaneous Retrieval of Upward Migrated Double-J Stent in Very Small Size Pediatric Patients Under Ultrasonic Guide

Purpose: To evaluate the safety of antegrade percutaneous retrieval migrated ureteral stent in very small size pediatric patients with ultramini instruments under ultrasonography guide. Materials and Methods: A total number of 10 out of 115 patients who were referred to our center with upward migrated Double-J (DJ) were candidates for antegrade approach from 2017 to 2020. The pyelocalyceal system was punctured in a prone position by using an 18-gauge disposable needle with Chiba tip and visualization of the upper tract by 3.5 MHz ultrasonic guidance. Then 0.038-inch J tipped guide wire was passed through the needle and the tract was dilated up to 6F under ultrasonographic guide. The 8F access sheath was positioned over the 6F dilator. The semirigid 6F ureteroscope was introduced through the sheath and DJ was removed with a grasper. Results: The mean age was 11.4 ± 5.48 months. The mean time from the previous surgery to DJ removal procedure was 6.4 ± 0.84 weeks. The mean operation time was 11.7 ± 1.76 minutes. All the patients were discharged from the hospital within the 1st day. There were no serious complications (grade 3, 4, or 5) according to Clavien-Dindo classification. Conclusion: The antegrade retrieval of upward migrated DJ with ultramini instrument under ultrasonographic guidance in failed cases of retrograde approach is a safe and effective approach in very small size pediatric patients.

What Is the Ideal Treatment for 20-30 mm Kidney Stones? Comparative Outcomes of 1197 Patients

Background: The purpose of this study is to compare the efficacy and safety of extracorporeal shockwave lithotripsy (SWL), retrograde intrarenal surgery (RIRS), mini-percutaneous nephrolithotomy (mPNL), and standard-percutaneous nephrolithotomy (stPNL) for the treatment of 20-30 mm kidney stones. Methods: The records of 1197 patients (SWL = 149, RIRS = 205, mPNL = 525, and stPNL = 318) from 8 centers were reviewed retrospectively. Four procedures were compared for stone-free rates (SFRs), auxiliary treatment, and associated complications. Results: Initial SFRs were 43.6%, 54.6%, 86.7%, and 87.7% in SWL, RIRS, mPNL, and stPNL, respectively (P < .001), whereas the final SFRs were 71.8%, 80%, 90.5%, and 89.6% (P < .001). The rate of auxiliary treatment in the groups was 38.3%, 26.8%, 5%, and 4.4%, respectively (P < .001). The initial and final SFRs in the mPNL and stPNL groups were higher than those in SWL and RIRS groups (P < .001). The rate for auxiliary treatment was lower in the mPNL and stPNL groups (P < .001). The operation time was longer in the RIRS group (P = .005). According to the Clavien-Dindo classification, the complication rate in the SWL group was lower than that in the surgical approaches (P < .001); however, no statistical difference was detected between RIRS, mPNL, and stPNL groups. mPNL and stPNL had a higher success rate than RIRS or SWL for treating 20-30 mm kidney stones. Conclusion: In the treatment of 2-3 cm renal stones, RIRS and PNL were more effective than SWL to obtain a better SFR and less auxiliary treatment rate. Compared with RIRS, mPNL and stPNL provided a higher SFR with similar complication rates.

Correlation analysis between renal anatomical factors and residual stones after an ultrasound-guided PCNL

Introduction

To predict the factors of residual stones after percutaneous nephrolithotomy (PCNL) by analyzing the characteristics of the renal anatomical structure in intravenous urography, so as to make a reasonable operation plan, reduce the risk of residual stones in PCNL, and improve the stone-free rate (SFR).

Methods

A retrospective study was performed between January 2019 and September 2020 for patients treated with PCNL. According to the results of a kidney ureter bladder review after PCNL, 245 patients were divided into a residual stone group (71 patients, stone size >4 mm) and a stone-free group (174 patients, stone size ≤4 mm). An independent sample t-test was used to analyze the age, the length and width of channel calices, the angle between the channel calices and the involved calices, and the length and width of the involved calices. The gender, the channel types, the number of channels, the degree of hydronephrosis, and the number of involved calices were analyzed by using the chi-square test. A score of p < 0.05 was considered statistically significant. At the same time, logistic regression analysis was carried out to explore the independent influencing factors of the SFR after PCNL.

Results

A total of 71 patients developed residual stones after surgery. The overall residual rate was 29.0%. The width of the channel calices (p = 0.003), the angle between the channel calices and the involved calices (p = 0.007), the width of the involved calices (p < 0.001), the channel types (p = 0.008), and the number of involved calices (p < 0.001) were all significantly correlated with residual stones after PCNL. Logistic regression analysis showed that the width of the channel calices (p = 0.003), the angle between the channel calices and the involved calices (p = 0.012), the width of the involved calices (p < 0.001), the channel types (p = 0.008), and the number of involved calyces (p < 0.001) were all independent influencing factors of the SFR after PCNL.

Conclusion

A larger caliceal neck width and angle can reduce the risk of residual stones. The more calyces that are involved, the higher the risk of residual stones. There was no difference between F16 and F18, but F16 had a higher SFR than F24.

Comparison of postoperative outcomes of mini percutaneous nephrolithotomy and standard percutaneous nephrolithotomy: a meta-analysis

Our study was aimed to evaluate the postoperative outcomes of Mini Percutaneous Nephrolithotomy (Mini-PCNL) and Standard Percutaneous Nephrolithotomy (Standard-PCNL) to determine the optimum option for patients with renal calculi. For publications published between January 2010 and April 2021, a comprehensive search of the PubMed, Cochrane Library, Web of Science, and EMBASE databases was done. The literatures were chosen based on the criteria for inclusion and exclusion. After the data were retrieved and the quality was assessed, the meta-analysis was performed using Review Manager Software (RevMan 5.4.1, Cochrane Collaboration, Oxford, UK). We selected 20 trials with a total of 4953 people out of 322 studies. There were 2567 patients treated with Mini-PCNL and 2386 patients treated with Standard-PCNL. Meta-analysis results showed no difference in stone-free rates (SFR, P = 0.93), fever (P = 0.83), and postoperative pain (VAS score) (P = 0.21) between Mini-PCNL and Standard-PCNL. Patients in the Mini-PCNL group experienced shorter hospital stay (P < 0.0001), less hemoglobin drop (P < 0.00001), less blood transfusion (P < 0.00001), higher postoperative tubeless (P = 0.0002), and fewer complications including bleeding (P = 0.01), perforation (P = 0.03), and leakage (P = 0.01). Compared with Standard-PCNL, operative time was longer in the Mini-PCNL group (P = 0.0005). Mini-PCNL had a shorter hospital stay, less hemoglobin drop, less blood transfusion, greater postoperative tubeless, fewer complications, and a longer operational time when compared to Standard-PCNL. SFR, fever, and postoperative pain were similar in both of them. Mini-PCNL may be a superior option for patients with proper size renal calculi.

Comparison between standard, mini and ultra-mini percutaneous nephrolithotomy for single renal stones: a prospective study

PURPOSE

Based on the current trend of miniaturization of instruments used in percutaneous nephrolithotomy (PCNL), it is necessary to compare different PCNL modalities regarding their access sheath size used. Thus, the safety and efficacy among standard, mini and ultra-mini PCNL (s-PCNL, m-PCNL, um-PCNL) were compared.

METHODS

We performed a prospective, non-randomized trial between January 2018 and July 2020. Patients with stones classified as Guy's stone score grade I were included. The set-up for s-PCNL and m-PCNL included a 30 Fr and 22 Fr percutaneous tract, respectively. In both set-ups, an ultrasonic/ballistic lithotripter was utilized. In the case of um-PCNL, a 12 Fr percutaneous tract was established. A high-power laser was used for lithotripsy. Hemoglobin drop, complication rate, length of hospital stay (LOS), stone-free rate (SFR) and operation time were evaluated.

RESULTS

A total of 84 patients, 28 patients per method, were evaluated. Hemoglobin drop was higher in the s-PCNL group when compared to m-PCNL (p = 0.008) and um-PCNL groups (p < 0.001), while um-PCNL group had the slightest hemoglobin drop. LOS was similar between s-PCNL group and m-PCNL group, but um-PCNL group required shorter hospital stay than the other two modalities (p < 0.001). The complication and transfusion rates as well as SFR did not differ between groups. Operation time in the um-PCNL set-up was longer compared to s-PCNL (p < 0.001) and m-PCNL (p = 0.011), whereas s-PCNL and m-PCNL did not differ significantly.

CONCLUSION

m-PCNL showed less hemoglobin drop, but similar operation time and SFR when compared to s-PCNL. um-PCNL showed even less hemoglobin drop, but the operation time was longer compared to the two other modalities.

Mini-Percutaneous Nephrolithotomy With an Endoscopic Surgical Monitoring System for the Management of Renal Stones: A Retrospective Evaluation

Purpose

To compare the outcomes and postoperative quality of life of patients with renal calculi who underwent standard percutaneous nephrolithotomy (sPNL), mini-invasive percutaneous nephrolithotomy (mPNL) or mPNL with an endoscopic surgical monitoring system (ESMS) using a retrospective clinical trial.

Methods

Eighty-six adult patients with renal stones who were treated with sPNL were retrospectively compared to ninety-two patients who were treated with mPNL between July 2014 and December 2017. Next, further studies were retrospectively conducted using a matched paired method. The ninety-two patients treated with mPNL were divided into two groups based on whether the endoscopic surgical monitoring system (ESMS) was used (ESMS-mPNL vs. non-ESMS-mPNL). The ESMS used strain gauge transducers to measure the inflow and outflow of irrigation solution. Bleeding and fluid absorption during endoscopic surgery could be accurately calculated by computer program in ESMS.

Results

The fluoroscopy time, complication rate, stone-free status and clinically insignificant residual fragment (CIRF) rate were not significantly different between the two groups (sPNL vs. mPNL). The mPNL group had a significantly longer operation time than the sPNL group, and the mPNL group exhibited a markedly reduced 12-h postoperative visual analogue pain scale (VAS) score, mean hospitalization time, and return to work time, had slightly reduced haemoglobin loss, and underwent more tubeless operations. Moreover, among the 92 patients who underwent mPNL, the operation time (P = 0.090), complication rate (P = 0.996), stone-free status (P = 0.731), CIRF rates (P = 0.125) and number of tubeless operations (P = 0.760) were not significantly different between the two subgroups (non-ESMS-mPNL vs. ESMS-mPNL); however, the patients in the ESMS-mPNL group had significantly longer irrigation times than those in the non-ESMS-mPNL subgroup, along with marked reductions in irrigation fluid, blood loss, haemoglobin loss, 12 h postoperative VAS score, mean hospitalization time, and return to work time.

Conclusions

mPNL is less painful than sPNL in patients undergoing treatment for 20–40 mm renal stones. Similar stone-free rates were achieved by the two procedures, but mPNL was superior to sPNL in terms of blood loss, discomfort, hospitalization time and return to work time. We think that ESMS-mPNL is less painful for patients and more efficacious than non-ESMS-mPNL, and ESMS-mPNL achieves a stone-free rate that is similar to non-ESMS-mPNL in patients receiving treatment for 20–40 mm kidney stones.

The safety and efficiency of a 1470 nm laser in obtaining tract hemostasis in tubeless percutaneous nephrolithotomy: a retrospective cross-sectional study

Objective

It is challenging to perform a tubeless percutaneous nephrolithotomy (PNL) in patients with tract bleeding. The present study was designed to study the safety and efficacy of the 1470 nm laser for hemostatic completion in tubeless PNL patients with tract bleeding.

Patients and Methods

Between January 2020 and October 2021, 120 patients were retrospectively included and divided into two groups. The hemostasis group included 60 patients receiving tubeless PNL, in which a 1470 nm laser was used to manage tract bleeding. The other group included 60 patients receiving tubeless PNL in which the hemostasis procedure was not performed, serving as the control group. The differences in the patients’ demographic characteristics, procedural information, and posttreatment outcomes between the two groups were statistically compared.

Results

The differences associated with sex, age, weight, body mass index, urine culture, stone burden, calyx of puncture, degree of hydronephrosis and comorbidities between the two groups were not statistically significant. Compared with the control group, the hemostasis group showed greatly reduced blood loss (0.61 ± 0.31 vs. 0.85 ± 0.46 g/dL) and decreased postoperative hospitalization duration (2.83 ± 0.81 vs. 4.45 ± 0.91 days). The differences in operative time, stone-free rate, Visual Analogue Score and postoperative complications between the two groups were not statistically significant. In the subgroup analysis, the obese patients and patients with moderate to severe hydronephrosis in the hemostasis group also showed a significantly less blood loss (0.51 ± 0.22 vs. 0.83 ± 0.48 g/dL; 0.54 ± 0.27 vs. 0.85 ± 0.47 g/dL, respectively) and shorter length of postoperative hospitalization (2.62 ± 0.51 vs. 4.47 ± 1.19 days; 2.97 ± 0.63 vs. 4.41 ± 0.91 days, respectively) than those in the control group.

Conclusions

Our results demonstrated that 1470 nm laser is a safe, feasible and effective method to obtain tract hemostasis in tubeless PNL.

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.

Renal puncture access via a nonpapillary track in percutaneous nephrolithotomy: an in vitro porcine kidney experience

Recently, an increasing number of investigators have debated the wide rule of the puncture to renal papilla in PCNL. We evaluated the effect of renal papillary and nonpapillary puncture on bleeding in an in vitro porcine kidney experience, with the aim of determining the safe puncture sites of collecting system in PCNL. A total of 70 fresh porcine kidneys were selected and subjected to nephrostomy. We performed a puncture through a renal papilla, infundibulum, renal column, or minor calyceal neck (including the front, back, up, and down). The primary outcome was the amount of bleeding. The results showed that the papillary puncture group yielded minimal bleeding (1.59 ± 1.01 ml/min) compared with the infundibular puncture group (6.25 ± 4.46 ml/min, P < .001), renal column puncture group (4.24 ± 3.79 ml/min, P = 0.001), and minor calyceal neck puncture group (2.27 ± 1.35 ml/min, P = 0.011). However, after stratifying by orientation, the up (1.75 ± 0.80 ml/min, P = 0.501) or down (1.77 ± 0.72 ml/min, P = 0.437) minor calyceal neck puncture group and papillary puncture group yielded comparable bleeding. In summary, nonpapillary puncture must be carefully considered. Infundibular and renal column punctures were inferior to papillary puncture, and up or down minor calyceal neck puncture may be a prudent choice in specific situations.

Minimal invasive percutaneous nephrolithotomy (Mini-PCNL) in children: Ultrasound versus fluoroscopic guidance

BACKGROUND

Miniaturization of endoscopic instruments in percutaneous nephrolithotomy (PCNL) allowed less invasive procedures with low complication rates, especially in children. This study was conducted to evaluate the safety and efficacy of ultrasonography-guided (USG) versus fluoroscopy-guided (FG) mini-PCNL in children.

MATERIALS AND METHODS

This is a retrospective comparative study conducted from June 2015 to June 2020. The sample included 70 children (35 pateints underwent USG mini-PCNL and 35 pateints underwent FG mini-PCNL). They were compared mainly by the patients' demographic characteristics, procedural information, and post-treatment outcomes. In the USG mini-PCNL group, puncturing was performed using a 3.5 MHz US probe, whereas fluoroscopy was utilized in the FG mini- PCNL group.

RESULTS

Both groups were comparable in terms of gender, previous history of failed ESWL, and hydronephrosis grade. The mean stone burden was 15.94 ± 3.69 mm and 19.20 ± 7.41 mm in USG and FG groups, respectively (p = 0.024). The stonefree rate (SFR) was 97.1% in the USG group and 94.3% in the FG group, which was not statistically significant (p = 0.16). Mean operative time in the USG group and FG group was 69.00 ± 13.33 minutes and 63.48 ± 16.90 minutes, respectively. Four (11.4%) patients in the FG group required blood transfusions to restore the hemodynamic state (p = 0.039). Fever was detected in 4 (11.4%) patients in the USG group and 15 (31.4%) patients in the FG group (p = 0.041).

CONCLUSIONS

In children, mini PCNL under USG is safe and as effective as fluoroscopy.

Comparison of laparoscopic pyelolithotomy and retrograde intrarenal surgery in the management of large renal pelvic stones

BACKGROUND

To compare the clinical outcomes of laparoscopic pyelolithotomy (LP) and retrograde intrarenal surgery (RIRS) in the management of large renal pelvic stones.

PATIENTS AND METHODS

This study included patients who presented with a single renal pelvic stone sized ≥20 mm and who were treated primarily by LP or RIRS. The patients were grouped based on the surgical procedure they underwent. We retrospectively examined and compared the age, the longest axis, and the surface area of the stone, operation time, hospitalization time, complications, and stone-free rates of the two groups.

RESULTS

Of the 156 patients included in the study, 44 had LP, and 112 had RIRS. Patients who received LP (13 males, 31 females) had a median age of 54 (18-79) years, while those who underwent RIRS (46 males, 66 females) had a median age of 54.5 (18-79). Patients who received LP were found to have larger median stone size (30 mm vs 24 mm, P = .003), longer operation time (100 minutes vs 70 minutes, P = .007), lower complication rate (2% vs 8.9%, P = .063), longer median hospital stay (3 days vs 1 day, P < .001) and better stone-free rate at the third month (90.9% vs 67.9%, P < .001).

CONCLUSION

LP is a safe and efficient procedure that could be used as an alternative to RIRS in managing large renal pelvic stones.

Mini-percutaneous nephrolithotomy is a safe alternative to extracorporeal shockwave lithotripsy for high-density, renal stones: a prospective, randomised trial

OBJECTIVES

To compare the outcomes of miniaturised percutaneous nephrolithotomy (mini-PCNL) and extracorporeal shockwave lithotripsy (ESWL) in the management of 10-20 mm, non-lower pole, renal stones.

PATIENTS AND METHODS

This prospective randomised double-arm trial was conducted at a tertiary care hospital in Egypt from February to December 2020. Adult patients with single, non-lower pole, high-density (≥1000 HU) renal stones were randomised to receive mini-PCNL or ESWL. The stone-free rate (SFR); operative, fluoroscopy and hospitalisation times; blood loss; auxiliary procedures; retreatment; unscheduled hospital readmission; and complications were compared between the groups.

RESULTS

The primary analysis included 34 patients in the mini-PCNL group and 33 in the ESWL group. Overall, the SFR was 97.1% in the mini-PCNL group vs 30.3% in the ESWL group (P < 0.001). All patients in the ESWL group required retreatment, and none of them were stone-free after the first ESWL session. None of the patients in the mini-PCNL group required retreatment. The overall operative time, fluoroscopy time, auxiliary procedure, retreatment, and unscheduled hospital readmission were significantly higher in the ESWL group. The hospital stay and decrease in the haemoglobin level were significantly higher in the mini-PCNL group. The groups were comparable for the overall complication rate.

CONCLUSIONS

Mini-PCNL is more effective than ESWL for treating 10-20 mm, high-density, non-lower pole renal stones. Mini-PCNL has the advantages of a high SFR and abolishing the need for retreatment and re-hospitalisation.

Comparison of mini-percutaneous nephrolithotomy and retroperitoneal laparoscopic ureterolithotomy for treatment of impacted proximal ureteral stones greater than 15 mm

BACKGROUND

The optimal treatment for large impacted proximal ureteral stones remains controversial. The aim of this study was to evaluate the efficacy, safety, and potential complications of mini-percutaneous nephrolithotomy (MPCNL) and retroperitoneal laparoscopic ureterolithotomy (RPLU) in the treatment of impacted proximal ureteral stones with size greater than 15 mm.

METHODS

A total of 268 patients with impacted proximal ureteral stones greater than 15 mm who received MPCNL or RPLU procedures were enrolled consecutively between January 2014 and January 2019. Data on surgical outcomes and complications were collected and analyzed.

RESULTS

Demographic and ureteral stone characteristics found between these two groups were not significantly different. The surgical success rate (139/142, 97.9% vs. 121/126, 96.0%, P = 0.595) and stone-free rate after 1 month (139/142, 97.9% vs. 119/126, 94.4%, P = 0.245) of RPLU group were marginally higher than that of the MPCNL group, but there was no significant difference. There was no significant difference in the drop of hemoglobin between the two groups (0.8 ± 0.6 vs. 0.4 ± 0. 2 g/dL, P = 0.621). The mean operative time (68.2 ± 12.5 vs. 87.2 ± 16.8 min, P = 0.041), post-operative analgesics usage (2/121, 1.7% vs. 13/139, 9.4%, P = 0.017), length of hospital stay after surgery (2.2 ± 0.6 vs. 4.8 ± 0.9 days, P < 0.001), double J stent time (3.2 ± 0.5 vs. 3.9 ± 0.8 days, P = 0.027), time of catheterization (1.1 ± 0.3 vs. 3.5 ± 0.5 days, P < 0.001), and time of drainage tube (2.3 ± 0.3 vs. 4.6 ± 0.6 days, P < 0.001) of MPCNL group were significantly shorter than that of the RPLU group. The complication rate was similar between the two groups (20/121, 16.5% vs. 31/139, 22.3%, P = 0.242).

CONCLUSIONS

MPCNL and RPLU have similar surgical success and stone clearance in treating impacted proximal ureteral stones greater than 15 mm, while patients undergoing MPCNL had a lower post-operative pain rate and a faster recovery.

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.

A systematic review and meta-analysis of minimally invasive vs. standard percutaneous nephrolithotomy in the surgical management of renal stones

The present study aimed to assess current evidence on the effectiveness and safety of minimally invasive vs. standard percutaneous nephrolithotomy (PCNL) in the management of renal stones. A systematic search of electronic databases, which included PubMed, EMBASE and the Cochrane Library up to May 2019 was performed. Using Review Manager statistical software (version 5.3), primary outcomes, including stone-free rates (SFRs), were evaluated. Meanwhile, analysis was also performed to compare secondary outcomes, such as peri- and postoperative complications and operative data. Fourteen studies involving 1,611 patients with renal stones were analyzed based on the inclusion criteria. On the basis of the present analysis, mini percutaneous nephrolithotomy (MPCNL) was proven to have non-inferior clinical efficacy with respect to the SFR compared with PCNL [odds ratio (OR)=1.10; 95% confidence interval (CI), 0.84-1.44; P=0.48]. In addition, the meta-analysis showed that MPCNL had a significantly lower hemoglobin decrease [mean difference (MD)=-0.68; 95% CI, -1.05 to -0.31; P=0.0003] and fewer blood transfusions (OR=0.36; 95% CI, 0.18-0.71; P=0.003) compared with PCNL. Moreover, the MPCNL group had a shorter inpatient stay (MD=-0.81; 95% CI, -1.55 to -0.08; P=0.03) compared with the PCNL group. However, the overall evidence was insufficient to suggest a statistically significant difference in the adverse event profile for MPCNL compared with PCNL. The present meta-analysis indicates that MPCNL is an effective method for treating renal stones. Compared with PCNL, MPCNL not only has similarly high SFRs but is also associated with less blood loss, fewer blood transfusions, more favorable recovery time and shorter inpatient stays. However, the findings of the present study should be further confirmed by well-designed prospective randomized controlled trials with a larger patient series.

Effect of Active Aspiration and Sheath Location on Intrapelvic Pressure During Miniaturized Percutaneous Nephrolithotomy

OBJECTIVE

To evaluate the effects of location of the tip of percutaneous sheath and nephroscope in the collecting system together with active aspiration on the Intrapelvic pressure measurements (IPP) during miniaturized percutaneous nephrolithotomy (miniPNL).

MATERIALS AND METHODS

The data of 20 patients underwent miniPNL in supine position was collected prospectively. IPP measurements were done with an 8 Fr urodynamic pressure measurement catheter in 4 different settings with respect to location of tip of sheath and nephroscope. All 4 settings were repeated with active aspiration. Totally measurements were done and compared in 8 different settings for 90 seconds in each patient.

RESULTS

Highest mean IPP measurements were recorded in setting II (35.3 ± 11.8 cm H2O) where the sheath was located in the calyx and the tip of the nephroscope was in the renal pelvis. When active aspiration was applied, the mean pressure measurements were significantly lower than the counterpart settings without aspiration (all P values <.0001). When the active aspiration was applied, intrarenal pressure measurements did not exceed 40 cm H2O in any settings in any of the patients.

CONCLUSION

Location of the tip of the sheath and the nephroscope has significant effect on IPP measurements. Active aspiration significantly lowers the IPP and keeps it <40 cm H2O. Endourologists should be aware of possible alterations in IPP during miniPNL and active aspiration should be kept in mind as an effective solution to decrease the risk of complications related to high IPP.

The clinical research of 1,470 nm laser in percutaneous nephrolithotomy

Background

Percutaneous nephrolithotomy (PCNL) is the primary method for the treatment of renal calculi. The preservation of the nephrostomy tube after operation brings severe pain to the patients. We use a 1,470 nm semiconductor laser to stop bleeding after the operation, which cannot reserve the nephrostomy tube, fully reflect its safety and effectiveness, and provide a new method for clinical practice.

Methods

Forty-two patients with renal stones who came to our hospital from March 2016 to September 2019 were randomly divided into two groups: laser operation group (20 patients) and traditional operation group (22 patients). The stone removal rate, surgical effect, and postoperative complications were compared between the two groups.

Results

There was no significant difference in the stone clearance rate between the two groups at the 4th week after operation (P>0.05). However, the incidence of postoperative infection, incision pain, and massive bleeding in the laser surgery group were lower than those in the traditional surgery group (P<0.05). However, there was no significant difference in urine extravasation and postoperative hematuria between the two groups (P>0.05). The average postoperative hospital stay in the laser surgery group was shorter than that in the traditional surgery group, and the difference was statistically significant (P<0.05). Simultaneously, there was no significant difference in operation time, intraoperative blood loss, and medical expenses between the two groups (P>0.05).

Conclusions

The 1,470 nm laser is safe, effective, and feasible in PCNL operation, especially in hemostasis of the renal puncture channel, and it is worth popularizing.

A comparison among PCNL, Miniperc and Ultraminiperc for lower calyceal stones between 1 and 2 cm: a prospective, comparative, multicenter and randomised study

Background

Conventional Percutaneous Lithotripsy (PCNL) has been an effective, successful and easy approach for especially > 1 cm sized calyceal stones however risks of complications and nephron loss are inevitable. Our aim is to compare the efficacy and safety of PCNL, MiniPerc (MP) and UltraMiniPerc (UMP) for lower calyceal stones between 1 and 2 cm with a multicenter prospective randomized study.

Methods

Between January 2015 and June 2018, 132 consecutive patients with single lower calyceal stone were enrolled. Patients were randomized in three groups; A: PCNL; B: MP; C: UMP. 44 patients for the Group A, 47 for Group B and 41 for Group C. Exclusion criterias were the presence of coagulation impairments, age of < 18 or > 75, presence of infection or serious comorbidities. Patients were controlled with computerized tomography scan after 3 months. A negative CT or an asymptomatic patient with stone fragments < 3 mm size were the criteria to assess the stone-free status. Patient characteristics, stone free rates (SFR) s, complications and re-treatment rates were analyzed.

Results

The mean stone size were 16.38, 16.82 and 15.23 mm respectively in Group A, B and C(p = 0.34). The overall SFR was significantly higher in Group A (86.3%) and B (82.9%) as compared to Group C (78%)(p < 0.05). The re-treatment rate was significantly higher in Group C (12.1%) and complication rates was higher in Group A (13.6%) as compared to others(p < 0.05). The hospitalization was significantly shorter in Group C compared to Group A (p = 0.04).

Conclusions

PCNL and MP showed higher efficacy than UMP to obtain a better SFR. Auxiliary and re-treatment rates were higher in UMP. On the other hand for such this kind of stones PCNL had more complications. Overall evaluation favors MP as a better indication in stones 1–2 cm size.

Standard versus Mini-Percutaneous Nephrolithotomy for Renal Stones: A Meta-Analysis

Objective:

To compare the standard percutaneous nephrolithotomy and mini-percutaneous nephrolithotomy in order to determine the optimal tract size for patients with renal stones.

Methods:

A systematic search of Web of Science, EMBASE, Cochrane Library, and PubMed databases was conducted for articles published through 20 August 2019, reporting on a comparison of the standard percutaneous nephrolithotomy and mini-percutaneous nephrolithotomy using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

Results:

Of 763 studies, 14 were considered for the evidence synthesis. A total of 1980 cases were included. Of these patients, 897 cases underwent standard percutaneous nephrolithotomy, and 1083 cases underwent mini-percutaneous nephrolithotomy. Stone-free rates were 87.6% (786 of 897 patients) for standard percutaneous nephrolithotomy and 87.8% (951 of 1083 patients) for mini-percutaneous nephrolithotomy ( p = 0.57). Tract sizes of 30F and 22–26F in standard percutaneous nephrolithotomy group shorten operation time compared with mini-percutaneous nephrolithotomy ( p = 0.02; p = 0.004; respectively). Leakage ( p = 0.04), bleeding ( p = 0.01), blood transfusion ( p < 0.00001), and renal pelvis perforation ( p = 0.02) were more common in standard percutaneous nephrolithotomy group than in mini-percutaneous nephrolithotomy group. Subgroup analysis showed only blood transfusion for 30F and 22–26F standard percutaneous nephrolithotomy group was more common than mini-percutaneous nephrolithotomy ( p < 0.0001, p = 0.005, respectively).

Conclusion:

Standard percutaneous nephrolithotomy was associated with higher leakage, bleeding, blood transfusion, and renal pelvis perforation, but had a shorter operation time. Tract size of 30F improved the stone-free rate compared with mini-percutaneous nephrolithotomy, but led to more complications. Tract size of 22–26F was no better than 30F or mini-percutaneous nephrolithotomy.

Does the renal parenchymal thickness affect the efficacy of the retrograde intrarenal surgery? A prospective cohort study

Retrograde intrarenal surgery (RIRS) is one of the minimally invasive main treatment modalities in renal stone disease. There are many factors which affect stone-free rate (SFR). Our study was based on the hypothesis that higher renal parenchymal thickness (RPT) which may include higher average number of nephrons provides better diuresis. We investigated the efficacy of RPT on success of RIRS. This study is a single-centered prospective surgical cohort study. A total of 383 patients were analyzed. Regularly followed 304 patients with unilateral kidney stone at single pole or renal pelvis and who underwent single-session RIRS were included in the final analysis, and the patients' preoperative and postoperative 1st and 3rd months' data were evaluated. RPT was measured on the non-contrast computed tomography (CT) images. ROC analysis was performed to estimate the cutoff value of RPT for SFR. Univariate and multivariate logistic regression analyses were used to model the relationship between RPT and SFR after RIRS. ROC analysis revealed the best cutoff value of the RPT for predicting residual stone as 19 mm for both the 1st and 3rd month visits with Youden indexes of 0.397 and 0.406, respectively. To the best of our knowledge, this is the first study which evaluated the effect of RPT on the efficacy of RIRS. RPT measurement is a cost-effective method that can be easily performed on routinely applied non-contrast CT and may have predictive value for the surgical success in patients with nephrolithiasis.

Minimally invasive versus standard endoscopic combined intrarenal surgery for renal stones: a retrospective pilot study analysis

PURPOSE

The effect of combining miniaturization with endoscopic combined intrarenal surgery (ECIRS) is unclear. Thus, we compared the treatment outcomes between minimally invasive ECIRS (mini-ECIRS) using 16.5 Fr percutaneous access sheath and standard ECIRS using 24 Fr access sheath for renal stones MATERIALS AND METHODS: We retrospectively analyzed consecutive patients who underwent single session mini or standard-ECIRS in the modified Valdivia position for renal stones between April 2009 and May 2016. To adjust for patient characteristics, 77 pairs were matched using preoperative parameters including age, sex, history of febrile urinary tract infection (UTI), stone surface area, number of involved calyces, and staghorn calculi.

RESULTS

The stone free rate (SFR) was similar between mini and standard ECIRS according to non-contrast computed tomography (61.1% vs. 52.0%, p = 0.388). The rate of perioperative complications exceeding grade 2 based on the Clavien-Dindo classification was similar in both groups (19.5% vs. 26.0%, p = 0.442). Severe complications exceeding grade 3 were also similar in both groups (2.6% vs. 3.9%, p > 0.99). Two cases of septic shock were noted in each group. Although there was no difference regarding bleeding-related complications (2.6% vs. 6.5%, p = 0.442), pseudoaneurysm or blood transfusion was not observed in the mini-ECIRS group. Pain visual analog scale values in the perioperative period were lower in the mini-ECIRS group (1.34 ± 1.08 vs. 1.69 ± 1.23, p = 0.062).

CONCLUSIONS

This study demonstrated that, compared to standard ECIRS, mini-ECIRS maintained SFR without increasing perioperative complications, tended to reduce postoperative pain and had a potential to reduce bleeding-related complications. This report suggests the advantages of ECIRS miniaturization for renal stones.

Safety and efficacy of a single middle calyx access (MCA) in mini-PCNL

To compare outcomes of a single middle calyx access (MCA) with a single upper or lower calyceal access in mini-PCNL. From May 2015 through August 2018, patients' files who underwent a single renal access mini-PCNL were retrospectively reviewed. All patients underwent fluoroscopic-guided access (16-20 F) in the prone position. They were categorized into group 1 (MCA) and group 2 (either upper or lower calyceal access). Compared preoperative items included stone location, size, number and complexity (according to Guy's score). The compared outcome parameters were complication and stone-free rates. The study comprised 512 consecutive patients, 374 patients in group 1 and 138 in group 2. A single MCA was utilized to access 95% of proximal ureteral calculi, 89% for ureteropelvic junction stones, and 84% for stones present in the pelvicalyceal system and ureter. MCA was used in 89% of complete staghorn stones and 73% of multiple stones. the Stone-free rates (93% vs 90.6%, P = 0.350) and the complications rates (8% vs 7.2%, P = 0.772) were comparable between group 1 and 2 despite that MCA was used for most cases with complex stones. Complications severity were also comparable (P = 0.579). Mini-PCNL performed through a single MCA is effective and safe. This access can be used for the treatment of renal and upper ureteral calculi of different complexities and locations.