Comparison of mini percutaneous nephrolithotomy and standard percutaneous nephrolithotomy for renal stones >2cm: a systematic review and meta-analysis

Micro cost-effectiveness analysis of standard vs. mini percutaneous nephrolithotomy A single Canadian institution's experience

INTRODUCTION

Mini-percutaneous nephrolithotomy (mPCNL ) has been described as an alternative to standard nephrolithotomy (sPCNL ) for select stones. Studies suggest that mPCNL has comparable stone-free rates, with potential for decreased complications and shorter hospital stay. Costs associated with both procedures present a challenge to Canadian institutions due to capital acquisitions of equipment and ongoing disposables. The objective of this study was to compare the cost-effectiveness of both procedures at our institution.

METHODS

A decision tree analytic model was developed to compare costs and outcomes of both procedures. Primary outcomes included assessment of total capital, operative, and hospitalization costs. Cost and outcome of peri- and postoperative parameters were obtained using a retrospective analysis of 20 mPCNL and 84 sPCNL procedures on 1-2.5 cm stones between January 2020 and June 2022, and supplemented with internal hospital expenditure records and literature outcome data. Descriptive statistics and regression models were performed.

RESULTS

The estimated total cost-per-patient was $7427.05 and $5036.29 for sPCNL and mPCNL, respectively, resulting in cost-savings of $2390.76 in favor of mPCNL, with a comparable stone-free rate. The savings were due to lower costs associated with complications and hospital stay. mPCNL had higher capital costs ($95 116.00) compared to sPCNL ($78 517.00), but per-procedure operative costs were lower for mPCNL ($2504.48) compared to sPCNL ($3335.72). Cost-per-case regression of total costs intersected at 5.51 cases when accounting for operative and hospitalization costs, and at 20 cases when only considering operative costs.

CONCLUSIONS

Despite higher upfront costs, mCPNL may represent a valid, cost-effective alternative to sPCNL for select stones due to clinical and economic benefits in Canadian institutions.

Is percutaneous nephrolithotomy effective and safe in infants younger than 2 Years old? Comparison of mini standard percutaneous nephrolithotomy

BACKGROUND

In this study, we aimed to compare the operative outcomes, postoperative outcomes, stone-free status and complications of SPCNL and MPCNL in infants younger than two years of age.

METHODS

We retrospectively analyzed 163 patients younger than two years of age who underwent percutaneous nephrolithotomy (PCNL) in our institution between September 1999 and March 2022. The patients were divided into two groups depending on the tract size. The MPCNL group consisted of 73 patients with a tract of 22 Fr or less, and the SPCNL consisted of 90 patients with a tract greater than 22 Fr.

RESULTS

The median age of 163 patients included in the study was 17.3 (range 7-24) months. Although the median stone size was lower in the SPCNL group, no statistically significant difference was found between the two groups in terms of stone size (p = 0.073). The median operative time was 74.8 min in the MPCNL group and 62.8 min in the SPCNL group, with a statistically significant difference (p = 0.002). Stone free rates (SFR) were 89 % and 90.8 % in the MPCNL and SPCNL groups, and the clinically insignificant residual fragments (CIRF) rates were 11 % and 4.6 %, respectively (p = 0.064). The fluoroscopy time, nephrostomy withdrawal time, and hospitalization stay were similar in the two PCNL groups (p = 0.535, p = 0.253, and p = 0.143, respectively). Postoperative fever was similar in MPCNL and SPCNL groups (p = 0.504). Although bleeding (6.7%-2.7 %) and blood transfusion (3.3%-1.4 %) rates were higher in the SPCNL group, there was no statistically significant difference (p = 0.248 and p = 0.420, respectively). Prolonged urinary leakage occurred in 6 (8.2 %) patients in the MPCNL group and 1 (1.1 %) patient in the SPCNL group, with a statistically significant difference (p = 0.026).

CONCLUSIONS

With the development of MPCNL, the use of SPCNL in infants has decreased considerably. However, SPCNL continues to be an effective and reliable method when needed in suitable patients. Although PCNL in infants shows some differences from adults, it is an effective and safe method for suitable patients.

LEVEL OF EVIDENCE

Although we created our study by retrospectively examining the pediatric urology data that we created prospectively, our study is of a retrospective nature. Therefore the Level of Evidence is 3.

Intraoperative computed tomography for detection of residual stones in endourology procedures: systematic review and meta-analysis

BACKGROUND

Success rates in endourological procedures, notably percutaneous nephrolithotomy (PCNL) and ureteroscopy (URS), have demonstrated suboptimal outcomes, leading to more reinterventions and radiation exposure. Recently, the use of intraoperative computed tomography (ICT) scans has been hypothesized as a promising solution for improving outcomes in endourology procedures. With this considered, we conducted a comprehensive systematic review and meta-analysis encompassing all available studies that evaluate the impact of the use of intraoperative CT scans on surgical outcomes compared to conventional fluoroscopic-guided procedures.

METHODS

This systematic review was conducted in accordance with PRISMA guidelines. Multiple databases were systematically searched up to December of 2023. This study aimed to directly compare the use of an ICT scan with the standard non-ICT-guided procedure. The primary endpoint of interest was success rate, and the secondary endpoints were complications and reintervention rates, while radiation exposure was also evaluated. Data extraction and quality assessment were performed following Cochrane recommendations. Data was presented as an Odds ratio with 95%CI across trials and a random-effects model was selected for pooling of data.

RESULTS

A comprehensive search yielded 533 studies, resulting in the selection of 3 cohorts including 327 patients (103 ICT vs 224 in non-ICT). Primary outcome was significantly higher in the experimental group versus the control group (84.5% vs 41.4% respectively, 307 patients; 95% CI [3.61, 12.72]; p<0.00001; I2=0). Reintervention rates also decreased from 32.6% in the control to 12.6% in the ICT group (OR 0.34; 95%CI [0.12,0.94]; p =0.04; I2= 48%), whereas complication rates did not exhibit significant differences. Radiation exposure was also significantly reduced in two of the included studies.

CONCLUSION

This meta-analysis highlights a favorable outcome with intraoperative CT scan use in PCNL procedures, showing a considerable increase in SFR when compared to standard fluoroscopy and nephroscopy. Despite limited studies, our synthesis underscores the potential of ICT scans to significantly reduce residual stones and their consequences for endourology patients, as reinterventions and follow-up ionizing radiation studies.

Postoperative antibiotic prophylaxis for percutaneous nephrolithotomy and risk of infection: a systematic review and meta-analysis

PURPOSE

The aim of this study is to perform a high-quality meta-analysis using only randomized controlled trials (RCT) to better define the role of postoperative antibiotics in patients undergoing percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

A literature search for RCTs in EMBASE, PubMed, and Web of Science up to May 2023 was conducted following the PICO framework: Population-adult patients who underwent PCNL; Intervention-postoperative antibiotic prophylaxis until nephrostomy tube withdrawal; Control-single dose of antibiotic during the induction of anesthesia; and Outcome-systemic inflammatory response syndrome (SIRS) or sepsis and fever after PCNL. The protocol was registered on the PROSPERO database (CRD42022361579). We calculated odds ratios (OR) and 95% confidence intervals (CI). A random-effects model was employed, and the alpha risk was defined as < 0.05.

RESULTS

Seven articles, encompassing a total of 629 patients, were included in the analysis. The outcome of SIRS or sepsis was extracted from six of the included studies, while the outcome of postoperative fever was extracted from four studies. The analysis revealed no statistical association between the use of postoperative antibiotic prophylaxis until nephrostomy tube withdrawal and the occurrence of SIRS/sepsis (OR 1.236, 95% CI 0.731 - 2.089, p=0.429) or fever (OR 2.049, 95% CI 0.790 - 5.316, p=0.140).

CONCLUSION

Our findings suggest that there is no benefit associated with the use of postoperative antibiotic prophylaxis until nephrostomy tube withdrawal in patients undergoing percutaneous nephrolithotomy (PCNL). We recommend that antibiotic prophylaxis should be administered only until the induction of anesthesia in PCNL.

Comparing Balloon Dilation to Non-Balloon Dilation for Access in Ultrasound-Guided Percutaneous Nephrolithotomy: A Systematic Review and Meta-Analysis

PURPOSE

This study aims to evaluate the safety and efficacy of ultrasound-guided balloon dilation compared to non-balloon dilation for percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

A systematic review and meta-analysis were conducted by searching PubMed, EMBASE, and the Cochrane Library. Results were filtered using predefined inclusion and exclusion criteria as described and meta-analysis was performed using Review Manager 5.4 software.

RESULTS

A total of six studies involving 1189 patients who underwent PCNL were included. The meta-analysis results demonstrated that compared to non-balloon dilation, balloon dilation was associated with reduced haemoglobin drop [mean difference (MD) = -0.26, 95% CI = -0.40 ~ -0.12, P = 0.0002], decreased transfusion rate [odds ratio (OR) = 0.47, 95% CI = 0.24 ~ 0.92, P = 0.03], shorter tract establishment time (MD = -1.30, 95% CI = -1.87 ~ -0.72, P < 0.0001) and shorter operation time (MD = -5.23, 95% CI = -10.19 ~ -0.27, P = 0.04).

CONCLUSIONS

Overall, ultrasound-guided balloon dilatation offered several advantages in PCNL procedures. It facilitated faster access establishment, as evidenced by shorter access creation time. Additionally, it reduced the risk of kidney injury by minimizing postoperative haemoglobin drop and decreasing the need for transfusions. Moreover, it enhanced the efficiency of surgery by reducing the operation time. However, it is important to note that the quality of some included studies was subpar, as they did not adequately control for confounding factors that may affect the outcomes. Therefore, further research is necessary to validate and strengthen these findings.

Modified biplanar (0-90°) endoscopic-guided puncture technique for percutaneous nephrolithtomy: refinement with endoscopic combined intrarrenal surgery to reduce fluoroscopy and operative time

INTRODUCTION

We aim to publish our innovative modified biplanar 0-90 endoscopic guided puncture technique for percutaneous nephrolithotomy in supine recorded with a GoPro® camera for standardization of the technique. It solves drawbacks of the fluoroscopic technique, i.e., in kidneys with complex anatomy, it may be challenging to distinguish calyces as they are often superposed, and it does not allow for all benefits of a combined endoscopic approach (1, 2). Our technique shortens puncture and fluoroscopic time and is easy to teach and reproduce.

METHODS

A 77-year-old female patient had previous double J insertion due to an obstructing stone in the right distal ureter. She managed to pass the distal stone but remained with the double J and a 20mm stone (1300HU) in the right renal pelvis. The shared decision was for the actual standard of care (3, 4) endoscopic combined intrarenal surgery (ECIRS). The MiniECIRS started with flexible ureteroscopy and a posterior calix which gave direct access to the stone was chosen. The tip of the flexible scope was used to mark point A with the C-arm in the 0-degree position and line B in the 90-degree position. Puncture was fast and the MiniECIRS was uneventful with a single mid-pole access guided by the flexible scope. The surgeon had a Full-HD GoPro® camera mounted on his head, controlled by the surgical staff. All essential surgical steps were recorded.

RESULTS

The quality of the recorded movie was graded as excellent, and the camera did not cause any discomfort to the surgeon. Operative and X-Ray time were 120minutes and 2minutes (7.64mGy). Hemoglobin drop was 0.8g/dL. The post-operative day-1 computed tomography scan was stone-free. The patient was discharged 24h after surgery. Kidney stent was left with a string and removed after 5days. The patient remained asymptomatic and metabolic evaluation revealed a calcium oxalate stone, low urinary volume and hypocitraturia which were treated with potassium citrate and hydration.

CONCLUSION

The Modified Biplanar (0-90 degree) Endoscopic-Guided Puncture Technique for Percutaneous Nephrolithotomy joins the reproducibility of the same technique under fluoroscopy with advantages regarding safety and efficiency of ECIRS.

Nomogram to predict the risk of adverse outcomes in patients with residual stones following percutaneous nephrolithotomy

PURPOSE

To investigate the risk factors associated with adverse outcomes in patients with residual stones after percutaneous nephrolithotomy (PCNL) and to establish a nomogram to predict the probability of adverse outcomes based on these risk factors.

METHODS

We conducted a retrospective review of 233 patients who underwent PCNL for upper urinary tract calculi and had postoperative residual stones. The patients were divided into two groups according to whether adverse outcomes occurred, and the risk factors for adverse outcomes were explored by univariate and multivariate analyses. Finally, we created a nomogram for predicting the risk of adverse outcomes in patients with residual stones after PCNL.

RESULTS

In this study, adverse outcomes occurred in 125 (53.6%) patients. Multivariate logistic regression analysis indicated that the independent risk factors for adverse outcomes were the diameter of the postoperative residual stones (P < 0.001), a positive urine culture (P = 0.022), and previous stone surgery (P = 0.004). The above independent risk factors were used as variables to construct the nomogram. The nomogram model was internally validated. The calculated concordance index was 0.772. The Hosmer-Lemeshow goodness-of-fit test was performed (P > 0.05). The area under the ROC curve of this model was 0.772.

CONCLUSIONS

Larger diameter of residual stones, positive urine culture, and previous stone surgery were significant predictors associated with adverse outcomes in patients with residual stones after PCNL. Our nomogram could help to assess the risk of adverse outcomes quickly and effectively in patients with residual stones after PCNL.

The Mayo adhesive probability score predicts postoperative fever and intraoperative hemorrhage in mini-percutaneous nephrolithotomy

PURPOSE

Contemporary predictive tools for miniaturized percutaneous nephrolithotomy (mPCNL) mainly focus on stone clearance but not perioperative complications, especially infection and hemorrhage. This study aimed to evaluate whether the Mayo adhesive probability (MAP) score, an index of the perinephric fat characteristics, can predict postoperative fever and intraoperative hemorrhage in mPCNL.

METHODS

This is a retrospective study recruiting 159 mPCNL patients from July 2018 to January 2022. MAP scores were recorded using preoperative computed tomography. Postoperative complications included postoperative fever and intraoperative bleeding, defined as hemoglobin drop.

RESULTS

Over half patients had the MAP score ≧ 3. Men, elderly, chronic kidney disease, and diabetes were associated with a higher MAP score. The patients with a higher MAP score were more likely to have postoperative fever after mPCNL. On multivariate analysis, preoperative positive urine culture (OR 2.68) and a higher MAP score (OR 2.28) were both significantly associated with postoperative fever. ROC curves analysis of the combination of these two factors on predicting postoperative fever showed AUC values were 0.731 (0.652-0.810). Moreover, a higher MAP score (OR 2.30) and longer operative time (OR 2.16) were significantly associated with higher hemoglobin drop on multivariate analysis.

CONCLUSION

A high MAP score was associated with postoperative fever and intraoperative hemorrhage in patients undergoing mPCNL. The MAP score can be a novel and easy predictive tool to help endourologists improve the awareness of mPCNL safety.

Percutaneous management of upper tract stones: from mini to maxi percutaneous nephrolithotomy

PURPOSE OF REVIEW

Percutaneous nephrolithotomy (PCNL) continues as the gold standard for the surgical management of large renal stones. This short review is intended to highlight recent publications on PCNL of all tract sizes, from mini to standard.

RECENT FINDINGS

Literature on PCNL in the last 2 years has focused on several main themes - decreasing complications, improving postoperative pain control, and new technology to improve outcomes. Mini-PCNL continues to prove effective and safe, with a new vacuum sheath showing promise of improving stone-free rates and decreasing infections. In terms of infections, preoperative midstream urine culture continues to be a poor indicator of postoperative infection. One of the biggest changes to PCNL practice is the reintroduction of tranexamic acid, which has shown to significantly decrease bleeding and improve outcomes. In terms of postoperative pain control, local blocks are effective and low risk.

SUMMARY

There are many options for surgeons when it comes to PCNL from sheath size to pain management to preoperative medication to decrease bleeding. Future research will continue to highlight, which advances are the most beneficial.

Efficacy and safety of various endosurgical procedures for management of large renal stone: a systemic review and network meta-analysis of randomised control trials

Urolithiasis is the most common benign urological health condition. It has contributed sizeable burden of morbidity, disability, and medical health expenditure worldwide. There is limited high level of evidence on the efficacy and safety of treatment options of large renal stones. This network meta-analysis has examined the effectiveness and safety of various large renal stone management strategies. Systematic review and network meta-analysis (NMA) study design was employed to summarize comparative randomized controlled trials on humans with a diagnosis of renal stone larger than or equal to 2 cm in size. Our searching strategy was based on the Population, Interventions, Comparison, Outcomes, and Study (PICOS) approach. Medline via PubMed, Embase, Google scholar, SCOPUS, Science Direct, Cochrane library, Web of Science, and ClinicalTrials.gov were searched from inception to March 2023 to find eligible articles. Data extraction, screening, selection and risk of bias assessment were conducted by two independent reviewers. We found ten randomised control trials which consists 2917 patients, nine of them were labeled as low risk and one article was high risk. This network meta-analysis found that SFR was 86% (95% CI 84-88%) for Mini-PCNL, 86% (95% CI 84-88%) for standard PCNL, 79% (95% CI:73-86%) for RIRS, and 67% (95%CI:49-81 for staged URS for management of large renal stone. Overall complication rate was 32% (95% CI 27-38%) for standard PCNL, 16% (95% CI 12-21%) for Mini-PCNL, and 11% (95% CI 7-16%) for RIRS. Mini-PCNL (RR = 1.14 (95% CI 1.01-1.27) and PCNL (RR = 1.13 (95% CI 1.01-1.27)) were statistically associated with a higher SFR compared to RIRS. The pooled mean hospital stays were 1.56 days (95% CI 0.93-2.19) for RIRS, 2.96 days (95% CI 1.78-4.14) for Mini-PCNL, 3.9 days (95% CI 2.9-4.83) for standard PCNL, and 3.66 (95% CI 1.13-6.2) for staged URS. Mini-PCNL and standard PCNL were the most effective treatment options with significant morbidity and length of hospital stay, while RIRS was the safest management option with acceptable SFR, low morbidity, and short hospital stay.

Concerns about stone free rate and procedure events of percutaneous nephrolithotripsy (PCNL) for 2-4 cm kidney stones by standard-PCNL vs mini-PCNL- comparative randomised study

BACKGROUND

To compare the efficacy and safety of standard percutaneous nephrolithotomy (PCNL) with mini- PCNL for kidney stones 2-4 cm.

METHODS

Eighty patients were enrolled in a comparative study, they were randomly divided into mini-PCNL group (n = 40) and standard-PCNL (n = 40). Demographic characteristics, perioperative events, complications, stone free rate (SFR) were reported.

RESULTS

Both groups showed no significant difference in clinical data about age, stone location, back pressure changes, and body mass index. The mean operative time was (95 ± 17.9 min) in mini-PCNL, and (72.1 ± 14.9 min). Stone free rate were 80% and 85% in mini-PCNL and standard-PCNL respectively. Intra-operative complications, post-operative need for analgesia, hospital stay were significantly higher in standard-PCNL compared to mini-PCNL (85% vs. 80%). The study followed CONSORT 2010 guidelines for reporting parallel group randomization.

CONCLUSION

Mini-PCNL is an effective and safe treatment of kidney stones 2-4 cm, it has the advantage over standard-PCNL being has less intra-operative events, less post-operative analgesia, shorter hospital stay, while operative time and stone free rate are comparable when considering multiplicity, hardness, and site of stones.

Comparative study between ultra-mini-percutaneous nephrolithotomy versus stented extracorporeal shock wave lithotripsy for treatment of renal stones in Egypt

Objectives

The purpose of this study is to compare results, safety and outcome of ultra-mini-percutaneous nephrolithotomy (PCNL) versus stented shock wave lithotripsy (SWL) for the management of renal calculi sized 10-20 mm.

Methods

This study was conducted at Urology Department, Faculty of Medicine, Ain Shams University. After meeting inclusion and exclusion criteria, 90 patients were randomized to either ultra-mini-PCNL group or stented SWL group through the closed-envelope technique, with 45 patients in each group. Patient data were collected preoperatively, immediately postoperatively and 2 and 4 weeks postoperatively assessing operative time, hospital stay, complications including haematuria, fever, the need for blood transfusion, residual stones and the need for retreatment.

Results

Stone-free rate (SFR) was higher in the ultra-mini-PCNL group compared to the stented SWL group, with no statistically significant difference with P-value = 0.316. As for the need for retreatment, it was slightly higher in the stented SWL group compared to the ultra-mini-PCNL group, yet this difference was statistically insignificant with P-value = 0.681.We found no statistically significant difference between both groups regarding post-operative complications including fever, haematuria and need for blood transfusion, respectively.Operative time and hospital stay were significantly higher in the ultra-mini-PCNL group compared to the stented SWL group with P-value < 0.001 for both.

Conclusion

Both stented SWL and ultra-mini-PCNL are good treatment choices for renal stones sized less than 2 cm with low complication rates. Stone size indices were significant predictor for the need for retreatment. Further studies to compare SFR based on stone size in both interventions are needed.

Comparison of the effect of miniaturized and standard percutaneous nephrolithotomy on renal function assessed with DMSA scintigraphy

INTRODUCTION AND OBJECTIVES

We aimed to present a clinical study that compares standard and miniaturized percutaneous nephrolithotomy (PNL) effects on kidney function with scintigraphic imaging in primary kidney stone patients.

MATERIALS AND METHODS

One hundred four patients were included in this prospective study between May 2014 and February 2017. Eligible patients were divided into two groups miniaturized PNL (mPNL) and standard PNL (sPNL) with matched-pair analysis (1:1 scenario). Technetium-99m Dimercaptosuccinic Acid cortical scintigraphy imaging was performed before and after the operation.

RESULTS

There were no differences between the two groups in terms of success rate (mPNL (63.5%) vs. sPNL (71.2%), p=0.403), serum creatinine, glomerular filtration rate, split renal functions pre- and postoperatively (p≥0.05). There was no relationship between the type of operation and new scar formation (p=0.780). The rates of serious complication (grades 3 and 4 according to modified Clavien-Dindo Classification) were higher in sPNL (p=0.034). Stone burden, duration of operation, hemoglobin drop, multiple access, blood transfusion, and angioembolization were higher in patients with scarred kidneys (p<0.001, p=0.008, p=0.004, p<0.001, p=0.003, p=0.001, respectively). In multivariate analysis, only multiple access was found statistically significant for predicting new scar formation (p<0.001, OR: 24.28).

CONCLUSIONS

Miniaturized and standard PNL are reliable and successful operations for treating large kidney stones. No significant difference was found between the operation types regarding a decrease in renal function.

Deep learning model-assisted detection of kidney stones on computed tomography

Introduction:

The aim of this study was to investigate the success of a deep learning model in detecting kidney stones in different planes according to stone size on unenhanced computed tomography (CT) images.

Materials and Methods:

This retrospective study included 455 patients who underwent CT scanning for kidney stones between January 2016 and January 2020; of them, 405 were diagnosed with kidney stones and 50 were not. Patients with renal stones of 0–1 cm, 1–2 cm, and >2 cm in size were classified into groups 1, 2, and 3, respectively. Two radiologists reviewed 2,959 CT images of 455 patients in three planes. Subsequently, these CT images were evaluated using a deep learning model. The accuracy rate, sensitivity, specificity, and positive and negative predictive values of the deep learning model were determined.

Results:

The training group accuracy rates of the deep learning model were 98.2%, 99.1%, and 97.3% in the axial plane; 99.1%, 98.2%, and 97.3% in the coronal plane; and 98.2%, 98.2%, and 98.2% in the sagittal plane, respectively. The testing group accuracy rates of the deep learning model were 78%, 68% and 70% in the axial plane; 63%, 72%, and 64% in the coronal plane; and 85%, 89%, and 93% in the sagittal plane, respectively.

Conclusions:

The use of deep learning algorithms for the detection of kidney stones is reliable and effective. Additionally, these algorithms can reduce the reporting time and cost of CT-dependent urolithiasis detection, leading to early diagnosis and management.

A novel nomogram and a simple scoring system for urinary leakage after percutaneous nephrolithotomy

Introduction:

The present study aimed to investigate the factors of prolonged urinary leakage (PUL) after percutaneous nephrolithotomy (PCNL) and develop a new and simple scoring system to predict it.

Patients and Methods:

We retrospectively reviewed patients with renal stones who underwent PCNL at the University of Health Sciences Izmir Bozyaka Training and Research Hospital between April 2011 and January 2020. The patients were divided into two groups according to the presence of PUL, and their preoperative and perioperative data were compared. A multivariate regression analysis was applied to examine the relationship between perioperative descriptors and PUL, and a nomogram was developed using significant predictors. Then, the individual components of the nomogram were assigned points to form a scoring system.

Results:

There were 92 and 840 patients in the groups with and without PUL, respectively. The results of the univariate logistic regression analysis showed that hydronephrosis grade, parenchymal thickness, duration of nephroscopy, and duration of nephrostomy catheter were significantly associated with PUL. Subsequently, a multivariate regression analysis was carried out with these four factors as possible independent risk factors of PUL after PCNL. Based on the results of this analysis, a nomogram prediction model was developed with an area under the curve value of 0.811, which was consequently used to develop a new simple score system consisting of three characteristics: parenchymal thickness (1–5 points), duration of nephroscopy (1–3 points), and hydronephrosis grade (1–3 points).

Conclusion:

A novel scoring system is a useful tool for predicting PUL in patients who have undergone percutaneous nephrolithotomy.