Future of kidney stone management: surgical intervention miniaturization of PCNL

Small tools, big impact and redefining endourology: the paradigm shift of ureteroscopy for large stones and percutaneous nephrolithotomy for small stones - a literature review

PURPOSE OF REVIEW

We aim to review the evolving paradigm in endourology, where technology has led us to manage small stones with ureteroscopy (URS) and large stones with miniaturized percutaneous nephrolithotomy (mPCNL) techniques. We analyse recent literature, their findings, emerging trends and newer technologies that are helping redefine modern day endourology in pushing these boundaries.

RECENT FINDINGS

A significant trend is the use of smaller devices to treat larger stones via ureteroscopy, and to treat smaller stones via percutaneous nephrolithotomy (PCNL). Improved laser technologies, smaller single use ureteroscopes and nephroscopes, suction access sheaths, all play a key role in this.The use of suction sheaths and vacuum assisted devices allows to control intrarenal pressure and help in reducing infectious and other complications whilst improving the stone-free rate (SFR). The treatment choice often depends on surgical expertise and available resources, guided by anatomical factors, stone composition and patient-specific considerations.

SUMMARY

The management of kidney stone disease has undergone a paradigm shift. While ureteroscopy is being done for larger renal stones, miniaturised PCNL is being done for small stones. This has been driven by a surge in technology, but a tailored and patient-centred approach is needed, and must be helped by guidelines and a multidisciplinary approach.

No ureteral catheter mini percutaneous nephrolithotomy (NUC-mPCNL) achieves enhanced recovery after surgery (ERAS)

Conventional mini percutaneous nephrolithotomy (mPCNL) typically necessitates the pre-operative placement of ureteral catheters. With the development of enhanced recovery after surgery (ERAS), we introduce a novel approach: no ureteral catheter mini percutaneous nephrolithotomy (NUC-mPCNL). To evaluate the efficacy and safety of this innovative procedure compared to mPCNL, we compared the total operative time, stone clearance rate (SCR), stone-free rate (SFR), and complications among patients undergoing either modality from January to September 2021. Our findings revealed a statistically significant reduction in the mean total operative time for the NUC-mPCNL group (42.6 ± 2.4 vs. 60.2 ± 3.4 min, p < 0.001). The SCR, SFR and CSFR were comparable between two groups (98.5% vs. 97.8%, 84.3% vs. 76.0%, 64.7% vs. 60.0%, p = 0.337, 0.295, 0.625). WBC rise, hemoglobin drop and neutrophil percentage rise were similar in both groups. The overall complication rate in the NUC-mPCNL group was lower; however, the difference was not statistically significant (Clavien I, II and III; 11 vs. 13, 1 vs. 2 and 1 vs. 1). Consequently, we conclude that NUC-mPCNL effectively shortens the operative time and holds potential for expedited postoperative recovery.

International Alliance of Urolithiasis (IAU) consensus on miniaturized percutaneous nephrolithotomy

Over the past three decades, there has been increasing interest in miniaturized percutaneous nephrolithotomy (mPCNL) techniques featuring smaller tracts as they offer potential solutions to mitigate complications associated with standard PCNL (sPCNL). However, despite this growing acceptance and recognition of its benefits, unresolved controversies and acknowledged limitations continue to impede widespread adoption due to a lack of consensus on optimal perioperative management strategies and procedural tips and tricks. In response to these challenges, an international panel comprising experts from the International Alliance of Urolithiasis (IAU) took on the task of compiling an expert consensus document on mPCNL procedures aimed at providing urologists with a comprehensive clinical framework for practice. This endeavor involved conducting a systematic literature review to identify research gaps (RGs), which formed the foundation for developing a structured questionnaire survey. Subsequently, a two-round modified Delphi survey was implemented, culminating in a group meeting to generate final evidence-based comments. All 64 experts completed the second-round survey, resulting in a response rate of 100.0%. Fifty-eight key questions were raised focusing on mPCNLs within 4 main domains, including general information (13 questions), preoperative work-up (13 questions), procedural tips and tricks (19 questions), and postoperative evaluation and follow-up (13 questions). Additionally, 9 questions evaluated the experts' experience with PCNLs. Consensus was reached on 30 questions after the second-round survey, while professional statements for the remaining 28 key questions were provided after discussion in an online panel meeting. mPCNL, characterized by a tract smaller than 18 Fr and an innovative lithotripsy technique, has firmly established itself as a viable and effective approach for managing upper urinary tract stones in both adults and pediatrics. It offers several advantages over sPCNL including reduced bleeding, fewer requirements for nephrostomy tubes, decreased pain, and shorter hospital stays. The series of detailed techniques presented here serve as a comprehensive guide for urologists, aiming to improve their procedural understanding and optimize patient outcomes.

Experimental study of a new technique for minimally invasive percutaneous nephrolithotomy: intelligent pressure-controlled minimally invasive percutaneous nephrolithotomy

BACKGROUND

To test the reliability and safety of a newly invented technique for minimally invasive percutaneous nephrolithotomy, intelligent pressure-controlled minimally invasive percutaneous nephrolithotomy (IPC-MPCNL).

METHODS

Eighteen kidneys of nine female pigs were randomly divided into three groups. Those in Groups A and B underwent IPC-MPCNL through the new system composed of a pressure-measuring MPCNL suctioning sheath and an irrigation and suctioning platform with pressure feedback control. The infusion flow rate was 500 ml/min in Group A and 750 ml/min in Group B. Those in Group C underwent MPCNL at an infusion flow rate of 500 ml/min. The renal pelvic pressure (RPP) monitored by a ureteral catheter and that monitored by the pressure-measuring sheath in Groups A and B were compared. The RPP in Group C was monitored by a ureteral catheter.

RESULTS

The RPP measured by the pressure-measuring sheath and that measured by the ureteral catheter in Group A was - 5.59 ± 1.95 mmHg and 4.46 ± 2.08 mmHg, respectively. The RPP measured by the pressure-measuring sheath and that measured by the ureteral catheter in Group B was - 4.00 ± 2.01 mmHg and 5.92 ± 2.05 mmHg, respectively. Hence, the RPPs measured by the pressure-measuring sheath in Groups A and B were consistent with those measured by the ureteral catheter. The RPP in Group C was 27.75 ± 5.98 mmHg (large fluctuations).

CONCLUSIONS

IPC-MPCNL can be used to accurately monitor the RPP and maintain it within a preset safe range via suction. The new technique and the new system are safe and reliable.

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.

Current evidence for suction in endourological procedures: comprehensive review of literature

PURPOSE OF REVIEW

To identify the latest advances on the utilization of suctioning devices in the surgical treatment of urinary stones.

RECENT FINDINGS

Advances are being made to incorporate suction and pressure control capabilities in percutaneous and ureteroscopic lithotripsy. Multiple retrospective studies and few prospective studies have shown that suctioning with minimally invasive percutaneous nephrolithotomy, commonly referred to as Super MiniPerc, can lead to better stone-free rates (SFR) and shorter operative time with lower incidence of infectious complications. Suctioning during retrograde intrarenal surgery (RIRS) has mainly been achieved through suctioning ureteral access sheath. Here as well, the incorporation of suction improved the SFR, but most importantly, reduced the risk of postoperative infectious complications.

SUMMARY

Theoretically suction in endourological procedures could facilitate stone debris removal and could reduce intrarenal pressure at the same time allowing for increased irrigation flow potentially decreasing operation time and infectious complications. These claims are supported in contemporary clinical studies, reporting superior SFR and reduced postoperative infectious complications in both percutaneous nephrolithotomy and RIRS.

Endoscopic Combined Intrarenal Surgery vs Percutaneous Nephrolithotomy for Large and Complex Renal Stone: A Systematic Review and Meta-Analysis

Background: Managing complex and large renal stones with percutaneous nephrolithotomy (PCNL) is difficult because of the likelihood of residual stones and multiple access. Endoscopic combined intrarenal surgery (ECIRS) is introduced as an improvement to the procedure to manage stones in one session. The objective of this systematic review and meta-analysis is to compare the efficacy and safety between ECIRS and PCNL for treating large and complex renal stones. Materials and Methods: We conducted a systematic review in the Embase, Scopus, and MEDLINE databases based on the 2020 Preferred Reporting Items for Systematic Review and Meta-Analyses guideline. Eligible studies comprised both randomized and nonrandomized studies comparing ECIRS and PCNL. Results: A total of five nonrandomized studies and one randomized controlled trial were included. The analysis was divided into two subgroups based on the PCNL type, a conventional PCNL (cPCNL) and a mini-PCNL (mPCNL). The one-step stone-free rate (SFR) of ECIRS were significantly higher compared with both the cPCNL (odds ratio [OR] 5.14, 95% confidence interval [CI] 2.54 to 10.4, p < 0.001) and mPCNL (OR 4.27, 95% CI 2.57-7.1, p < 0.001). There were no significant differences in mean operative time and hemoglobin drop between both groups (p > 0.05). The use of auxiliary procedures was significantly higher in both PCNL groups compared with the ECIRS group (OR 0.19, 95% CI 0.13-0.30, p < 0.001). The overall complication rate of ECIRS was lower compared with PCNL (OR 0.43, 95% CI 0.21-0.85, p = 0.02), especially urosepsis, in which the incidence was lower compared with cPCNL (OR 0.14, 95% CI 0.02-0.78, p = 0.02), but not mPCNL (p > 0.05). Conclusion: ECIRS is an effective and safe treatment particularly for large and complex nephrolithiasis, with significantly higher one-step SFR, a lower necessity for auxiliary procedures, and a lower complication rate compared with PCNL.

Efficacy of Super-Mini-PCNL and Ureteroscopy in Kidney Stone Sufferers and Risk Factors of Postoperative Infection

To investigate the efficacy of super-mini-PCNL (SMP) and ureteroscopy in kidney stone (KS) sufferers and learn the risk factors of postoperative infection. A retrospective analysis was performed on 180 KS sufferers who were diagnosed and treated in our hospital from May 2019 to May 2021. They were enrolled into an observation group (OG, n = 104) and a control group (CG, n = 76) based on different treatment methods. Therein, the former was treated with SMP, while the latter was treated with ureteroscopy. The operation time, blood loss, hospital stay, recent stone-free rate (one week after operation), changes of serum creatinine (SCr), blood urea nitrogen (BUN), and cystatin C (CysC) levels before and after operation and complications were compared. Those sufferers were assigned to infected and uninfected groups based on their postoperative infection. The risk factors were assessed through logistic regression, and the model formula was established. The predictive value of this model for infection was tested through RO. Compared with CG, the operation time of the OG was longer, the blood loss and hospital stay were lower (P < 0.05), and the stone-free rate was higher (P < 0.05). Renal function indexes before and after treatment (P > 0.05) and postoperative complications revealed no significant difference (P > 0.05). Logistic regression analysis manifested that preoperative urinary tract infection (OR: 4.690, 95% CI: 1.170-18.802), preoperative blood glucose level (OR: 11.188, 95% CI: 2.106-59.442), positive urine culture (OR: 10.931, 95% CI: 2.453-48.705), and infectious stones (OR: 3.951, 95% CI: 1.020-15.300) were independently related to infection. The risk prediction equation is logit(p)=-8.913+1.545 × X1+2.415 × X2+2.392 × X3+1.374 × X4, with a goodness-of-fit value of 0.545. The AUC is 0.930, so SMP is superior to ureteroscopy in KS sufferers. Preoperative urinary tract infection, preoperative blood glucose level, positive urine culture, and infectious stones are independently related to infection.

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.

Efficacy and safety of 3D printing-assisted percutaneous nephrolithotomy in complex renal calculi

This study evaluated the efficacy and safety of 3D printing technology combined with percutaneous nephrolithotomy in the treatment of complex renal calculi. Ninety patients with complex renal calculi were randomly divided into a 3D printing group (45 patients) and a control group (45 patients). In the 3D printing group, a patient-specific 1:1 3D printing model was established based on the patient's thin-layer CT scanning data. A 3D printing model was used for preoperative communication between doctors and patients. Preoperative puncture training, channel design, residual stone prediction, and percutaneous nephrolithotomy were performed under the guidance of a 3D printing model and B-ultrasound. The control group was treated with the conventional B-ultrasound-guided puncture method. Results suggest that there was a statistically significant difference between the two groups (P < 0.05). The overall score of the doctor-patient communication objects in the 3D printing group was 19.32 ± 1.57 points, and in the control group, it was 14.51 ± 2.13 points. The operation time of the 3D printing group was 103.21 ± 13.49 min, and that of the control group was 126.12 ± 25.87 min. The calculi clearance rate of the 3D printing group was 96%, while that of the control group was 80%. The incidence of postoperative complications was 6.67% in the 3D printing group and 22.22% in the control group. Compared with traditional percutaneous nephrolithotomy, 3D printing technology combined with percutaneous nephrolithotomy can significantly enhance the effectiveness of doctor–patient communication, shorten operation time, reduce operation bleeding, improve the stone clearance rate, reduce the incidence of complications and shorten the length of hospital stay. The proposed method is thus a safe and effective method to treat complex renal calculi.

The characteristics and influencing factors of fever in postoperative patients undergoing percutaneous nephrolithotomy: A retrospective analysis

Percutaneous nephrolithotomy (PCNL) is commonly used for the treatment of upper urinary calculi in clinical setting, and fever is a common complication after PCNL. It is necessary to evaluate the risk factors of fever in patients undergoing PCNL, to provide insights into the management of PCNL.Patients who underwent PCNL in our hospital from January 2018 to August 2020 were included. The clinical data of postoperative fever and no fever patients were collected and assessed. Logistic regression analyses were conducted to analyze the risk factors for fever in patients undergoing PCNL.A total of 276 patients undergoing PCNL were included, the incidence of postoperative fever for patients undergoing PCNL was 19.39%. No significant differences in the gender, body mass index, alcohol drinking, smoking, hypertension, hyperlipidemia, intraoperative blood infusion, length of hospital stay between fever patients, and no fever patients were found (all P > .05). There were significant differences in the age, diabetes, size of stones, duration of surgery between fever patients, and no fever patients (all P < .05). Age ≥60 years (odds ratio [OR] 2.143, 95% confidence interval [CI] 1.101∼3.264), diabetes (OR 2.218, 95% CI 1.176∼4.642), size of stone ≥2 cm (OR 1.428, 95%CI 1.104∼2.055), duration of surgery ≥100 minutes (OR 1.334, 95% CI 1.015∼1.923) were the risk factors for fever in patients with PCNL (all P < .05). Escherichia coli (48.44%), Staphylococcus aureus (18.75%), and Candida albicans (10.93%) were the top 3 pathogenic bacteria of urine culture.Fever is one of the common complications after PCNL. Patients with high-risk factors should be given full attentions and take corresponding preventive measures targeted on risks.

The Outcomes of Minimally Invasive Percutaneous Nephrolithotomy with Different Access Sizes for the Single Renal Stone ≤25 mm: A Randomized Prospective Study

OBJECTIVES

The aim of this study was to provide a randomized controlled trial comparing the outcomes of different access sizes used in the solo ultrasonic-guided minimally invasive percutaneous nephrolithotomy (mini-PCNL).

METHODS

From January 2018 to December 2019, a total of 160 cases with single renal stones of <25 mm were randomized to undergo mini-PCNLs with Fr16, Fr18, Fr20, or Fr22 accesses. All accesses were established with the axis of the target calyx as the marker for puncture location and then expanded to the desired size. Hemoglobin reduction, operative time, stone-free rate, complications, etc., were all recorded and assessed.

RESULTS

The demographic data were similar, and there were no significantly intergroup differences in stone-free rate, complications, and hospital stay time. The hemoglobin reduction was comparable and was 0.9 ± 0.6, 0.9 ± 0.7, 1.0 ± 0.5, and 1.1 ± 0.7 g/dL for the groups Fr16, Fr18, Fr20, and Fr22, respectively. The operative time was 53.4 ± 14.5, 48.5 ± 15.2, 42.8 ± 13.3, and 43.3 ± 13.1 min for the 4 groups, which decreased significantly from group Fr16 to Fr20, but there was no significant difference between Fr20 and Fr22 groups.

CONCLUSIONS

The axis of target calyx is a reliable marker for establishment of percutaneous renal access under ultrasonic guidance. The surgical outcomes of different access sizes were comparable, but the operation time was significantly shortened with the increase of size. However, Fr22 was not more efficient than Fr20.

The best treatment approach for lower calyceal stones ≤ 20 mm in maximal diameter: mini percutaneous nephrolithotripsy, retrograde intrarenal surgery or shock wave lithotripsy. A systematic review and meta-analysis of the literature conducted by the European Section of Uro-Technology and Young Academic Urologists

INTRODUCTION

The highest in quality data in the literature which compared mini percutaneous nephrolithotripsy (mPCNL), retrograde intrarenal surgery (RIRS) and shock wave lithotripsy (SWL) for the management of lower pole stone (LPS) with a maximal diameter ≤20mm were investigated by means of systematic review (SR) and meta-analysis.

EVIDENCE ACQUISITION

A SR of the literature was conducted on PubMed®, Cochrane, SCOPUS® and EMBASE® in January 2020. The study complied with the PRISMA statement and recommendations of the EAU Guidelines office. Only randomized controlled trials (RCTs) comparing retrograde intrarenal surgery (RIRS), shock wave lithotripsy (SWL) and mini-percutaneous nephrolithotripsy (mPCNL) were selected for the meta-analysis. The endpoints were the efficacy of each modality, measured by stone-free rate (SFR), operative time and retreatment rate and the safety of each method, based on hospitalization time and complications. Subgroup analyses for stones with a maximal diameter <10mm and 10-20 mm were performed.

EVIDENCE SYNTHESIS

Twenty-one RCTs were included in the meta-analysis. mPCNL had the highest SFR and the lowest retreatment rate among the three modalities, while SWL had the lowest SFR and the highest retreatment rate. The operative and hospitalization time were shorter in the case of SWL, whereas they were similar in the case of mPCNL and RIRS. The highest complication rate was observed in mPCNL group, which accounted for 8.3-22.4%, while RIRS and SWL had similar complication rates, which ranged between 1.3-31.4% and 0-48.5%, respectively. Further classification of the complications according to Clavien-Dindo system revealed that SWL had lower grade II complication rates compared to mPCNL and RIRS. Regarding stones <10mm, SWL and RIRS had similar SFR, complication rate, operation and hospitalization time. SWL had higher retreatment rate.

CONCLUSIONS

For LPSs ≤20mm, mPCNL provides the highest SFR and the lowest retreatment rate. This modality has a higher complication rate and longer hospital stay in comparison to the other modalities. SWL provides the lowest SFR with the highest retreatment rate. RIRS has similar complication rate to SWL and could be preferred over SWL. For stones up to 10mm, SWL may provide a valid alternative. Despite a higher retreatment rate, its SFR is similar to RIRS.

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.

Simulation-Based Percutaneous Renal Access Training: Evaluating a Novel 3D Immersive Virtual Reality Platform

Introduction: Percutaneous nephrolithotomy (PCNL) is the gold standard treatment for patients with a large stone burden. There are a variety of methods to teach this important endourologic procedure, including simulation. We evaluated three different PCNL simulation platforms for potential use in teaching and assessing percutaneous renal access skills. Materials and Methods: Urology residents, fellows, and faculty were recruited to participate in this study, which included completing standardized tasks on three PCNL simulation platforms: a virtual reality (VR) simulator (PercMentor, 3D Systems™), a porcine tissue simulator (Cook™ Medical), and a new 3D immersive VR simulator-Marion K181 (Marion Surgical™). Participants were asked to complete a standardized task-gaining prone percutaneous renal access using a fluoroscopic-guided technique. Participants were asked to rate the simulators, and performance data were recorded for analysis. Results: A total of 18 participants with varying levels of PCNL experience completed the study. The Marion K181 had higher ratings by participants in all domains (realism, tactile feedback, instrument movement, renal anatomy, fidelity of simulation, utility as teaching tool) compared with the PercMentor (p < 0.05) but did not differ in any domain when compared with the porcine PCNL model. Participants felt that the Marion K181 was comparable with the porcine PCNL model as a teaching tool, but had the advantage of not requiring radiation exposure. Fluoroscopy time was the variable that most consistently correlated with participant PCNL experience and level of training, across all three PCNL simulation platforms. Conclusions: There are a variety of PCNL simulation platforms available for teaching percutaneous renal access skills. Based on our initial comparative study, there is validity evidence to support the use of the novel Marion K181 PCNL simulator as a training tool rather than higher fidelity models requiring real radiation exposure. However, evidence is yet lacking for its use as an assessment tool.