Percutaneous nephrolithotomy (PCNL) in patients with previous open stone surgery

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.

Percutaneous nephrolithotomy in previously operated patients: A prospective study

Purpose:

To determine the effect of previous renal stone surgery on result and complications of percutaneous nephrolithotomy (PCNL).

Materials and Methods:

Total 300 patients were enrolled in the study. We enrolled 100 surgery-naive cases (those with no history of any renal surgery) as control and labeled them as Group A. Group B comprised 100 cases who had PCNL in the past. Group C constituted 100 patients who had open renal stone surgery in the past. Stones were classified using Guy's stone score. PCNL was performed by standard technique in prone position and technical features encountered during operation and outcomes were compared between groups. Complications were graded using modified Clavien grading system.

Results:

There were no differences between the three groups in age, gender, body mass index, stone burden, and stone opacity. Multiple calyceal stones and distorted pelvicalyceal system anatomy were more in Group C, but stone score showed no statistically significant difference from other groups. The mean operative time (68.91 ± 21.27 min) and fluoroscopy time (264.40 ± 74.90 s) were longer in Group C, but there was no statistically significant difference between the groups. Multiple access was significantly more common in Group C compared to the other two groups (P < 0.001). Access location too did not show any statistically significant difference between the groups. Postoperative complications were more in previous stone surgery patients, but did not show statistically significant difference.

Conclusion:

PCNL is a safe and effective treatment modality for patients with renal stones regardless of history of previous PCNL or open renal surgery.

Mortality from kidney stone disease (KSD) as reported in the literature over the last two decades: a systematic review

INTRODUCTION

Current trends show a rising incidence of kidney stone disease (KSD) globally, with a lifetime risk of 10% and increasing hospital admissions. However, it is not perceived as a life-threatening condition and there are no publications examining its mortality rate. The aim of this review was to report on the number of KSD mortalities in the literature from the past two decades, identify risk factors, and to summarize their key learning points.

METHODS

A search was conducted for full-text English language articles that reported on KSD associated mortality, following intervention or conservative treatment, published between 1999 and 2017, using PubMed, MEDLINE, EMBASE, Scopus, CINAHL, Clinicaltrials.gov, Google Scholar and The Cochrane Library. Study quality and risk of bias assessment was undertaken using a validated critical appraisal tool from the Joanna Briggs Institute.

RESULTS

Of the 2786 articles identified, 34 were included. Of the total number of reported mortalities (2550), 21% were related to intervention. Sepsis was the leading cause of mortality. Risk factors identified were patients with multiple co-morbidities, spinal cord injury or neurogenic bladder and high stone burden. The main recommendations suggested were to treat pre-operative UTI or use prophylactic antibiotics and to reduce operative duration. The included studies were of moderate to good quality.

CONCLUSION

Pre-procedural optimization of the patients is the key to avoiding KSD mortality, and care should be taken in patients with multiple co-morbidities. Surgeons should meticulously plan for patients with high stone burden to reduce their operative time, as mortality can be procedural related.

The effects of previous open renal stone surgery types on PNL outcomes

INTRODUCTION

Our aim was to demonstrate the effect of insicion of renal parenchyma during open renal stone surgery (ORSS) on percutaneous nephrolithotomy (PNL) outcomes.

METHODS

Patients with history of ORSS who underwent PNL operation between June 2005 and June 2015 were analyzed retrospectively. Patients were divided into two groups according to their type of previous ORSS. Patients who had a history of ORSS with parenchymal insicion, such as radial nephrotomies, anatrophic nephrolithotomy, lower pole resection, and partial nephrectomy, were included in Group 1. Other patients with a history of open pyelolithotomy were enrolled in Group 2. Preoperative characteristics, perioperative data, stone-free status, and complications were compared between the groups. Stone-free status was defined as complete clearance of stone(s) or presence of residual fragments smaller than 4 mm. The retrospective nature of our study, different experience level of surgeons, and lack of the evaluation of anesthetic agents and cost of procedures were limitations of our study.

RESULTS

123 and 111 patients were enrolled in Groups 1 and 2, respectively. Preoperative characteristics were similar between groups. In Group 1, the mean operative time was statistically longer than in Group 2 (p=0.013). Stone-free status was significantly higher in Group 2 than in Group 1 (p=0.027). Complication rates were similar between groups. Hemorrhage requiring blood transfusion was the most common complication in both groups (10.5% vs. 9.9%).

CONCLUSIONS

Our study demonstrated that a history of previous ORSS with parenchymal insicion significantly reduces the success rates of PNL procedure.

Impact of previous open renal surgery on the outcomes of subsequent percutaneous nephrolithotomy: a meta-analysis

OBJECTIVE

The aim of this study was to systematically compare the perioperative outcomes of percutaneous nephrolithotomy in patients with or without previous ipsilateral open renal surgery (POS).

DESIGN

Systematic searches of the PubMed, Web of Science and Cochrane Library databases were used to identify relevant studies, and, following literature screening and data extraction, a meta-analysis was performed.

RESULTS

17 retrospective cohort studies involving 4833 procedures (4784 patients) were included. No statistically significant differences were observed between patients with or without POS in terms of supracostal access; single/multiple tracts; metal dilator need; time required to access the collecting system; fluoroscopic duration; demand for analgesics; hospital stay; final stone-free rate; and risk of developing certain complications (eg, fever, haemorrhage, haemo/hydro/pneumothorax, blood transfusion, urinary tract infection and sepsis) as well as regarding the risk of total complications. Patients with POS, however, had a greater drop in haemoglobin (weighted mean difference (WMD), 1.78 g/L; 95% CI 1.09 to 2.47; p<0.00001) and higher risk of bleeding that required angiographic embolisation (relative risk (RR), 3.73; 95% CI 1.36 to 10.21; p=0.01). In addition, patients with POS also had a lower initial stone-free rate (RR, 0.96; 95% CI 0.92 to 0.99; p=0.007) and more secondary treatment (RR, 1.61; 95% CI 1.09 to 2.37; p=0.02). Sensitivity analysis produced comparable results except for differences in operative time and initial stone-free rate, which did, however, prove to be statistically insignificant (p=0.16 and 0.69, respectively).

CONCLUSIONS

Current evidence suggests that percutaneous nephrolithotomy in patients with POS is associated with a significantly greater drop in haemoglobin, higher risk of requiring angiographic embolisation and auxiliary procedures, potentially longer operative time, and lower initial stone-free rate than percutaneous nephrolithotomy in patients without POS.

Percutaneous nephrolithotomy with one-shot dilation method: Is it safe in patients who had open surgery before?

INTRODUCTION

This study aimed to evaluate whether one-shot dilatation technique is as safe in patients with a history of open-stone surgery as it is in patients without previous open-stone surgery.

METHODS

Between January 2007 and February 2015, 82 patients who underwent percutaneous nephrolithotomy (PNL) surgery with one-shot dilation technique who previously had open-stone surgery were retrospectively reviewed and evaluated (Group 1). Another 82 patients were selected randomly among patients who had PNL with one-shot dilation technique, but with no history of open renal surgery (Group 2). Age, gender, type of kidney stone, duration of surgery, radiation exposure time, and whether or not there was any bleeding requiring perioperative and postoperative transfusion were noted for each patient.

RESULTS

The stone-free rates, operation and fluoroscopy time, and peroperative and postoperative complication rates were similar in both groups (p>0.05).

CONCLUSIONS

Our experience indicated that PNL with one-shot dilation technique is a reliable method in patients with a history of open-stone surgery.

The Efficacy of Percutaneous Nephrolithotomy Using Pneumatic Lithotripsy vs. the Holmium Laser: a Randomized Study

The objective of the study is to compare the efficacy of percutaneous nephrolithotomy using holmium laser vs pneumatic lithotripsy. From August 2010 to March 2014, 200 patients with double kidney and single kidney stones without previous operations or other diseases were randomized into two groups according to the type of lithotripter used: pneumatic (n = 100) and laser (n = 100). The preoperative, intraoperative, and post-operative follow-up findings were analyzed and compared. The average stone size was similar in both the pneumatic and holmium laser lithotripsy groups (202.8 ± 52.6 mm² vs. 200.3 ± 50.8 mm²). No significant difference was found between the operation time for the two groups (55.9 ± 16.5 min vs. 62.4 ± 17.6 min). The concentrations of creatinine in both groups increased 2-24 h after the operation and decreased to a normal level 1-4 days after the operation in both groups. Renal diuretic scan revealed that the peak and the renal index were both abnormal after the operation but became normal 4 days after the operation in both groups. No significant difference of creatinine concentration or the diuresis renogram was observed between the two groups. However, two cases in the holmium laser group had almost lost the renal function of the operated kidney 1 year later. Both pneumatic and holmium laser lithotripsy can be associated with acute renal injury in some patients after the operation without any significant difference. However, some infrequent severe renal function damage in laser lithotripsy should be noted.

Outcome and complications of percutaneous nephrolithotomy as primary versus secondary procedure for renal calculi

PURPOSE

To compare the efficacy of percutaneous nephrolithotomy (PCNL) as a primary procedure of patients following previous open surgery or post percutaneous nephrolithotomy (PCNL) for renal calculi.

MATERIALS AND METHODS

The medical records of 367 patients who underwent PCNL by a single surgeon from January 2008 to December 2013 were reviewed retrospectively. All patients were divided into 3 Groups. Group-1 (n=232) included patients with no history of ipsilateral open stone surgery. Group 2 (n=86) patients had undergone one or more open stone surgeries before PCNL, patients with failed or recurrence following PCNL were placed in Group-3 (n=49). The demographic data, operation duration, stone free rate (SFR), number of attempts to access the collecting system and intra operative and postoperative complications between the three Groups were compared.

RESULTS

There was no difference in sex, Body Mass Index (BMI), stone burden and laterality among the three Groups. Operation time was significantly less in first Group, while there was a statistically significant difference in operation duration between second and third Groups (p<0.05). The number of attempts to enter the collecting system was lower in the first Group in comparison to other two Groups (p<0.5). There was no significant differences among three groups in stone free rate. Intra operative and postoperative complications were slightly more frequent in Groups 2 and 3. Mortality occurred in 1 patient with colon perforation in Group-2.

CONCLUSION

Our study demonstrated that PCNL can be performed in patients even as secondary procedure without further complications.

Does previous open renal surgery or percutaneous nephrolithotomy affect the outcomes and complications of percutaneous nephrolithotomy

In this study, we aim to evaluate the effectiveness and safety of PNL in patients with a history of open renal surgery or PNL by comparing with primary patients and to compare impact of previous open renal surgery and PNL on the success and complications of subsequent PNL. Charts of patients, who underwent PNL at our institute, were analyzed retrospectively. Patients were divided into three groups according to history of renal stone surgery. Patients without history of renal surgery were enrolled into Group 1. Other patients with previous PNL and previous open surgery were categorized as Group 2 and Group 3. Preoperative characteristic, perioperative data, stone-free status, and complication rates were compared between the groups. Stone-free status was accepted as completing clearance of stone and residual fragment smaller than 4 mm. Eventually, 2070 patients were enrolled into the study. Open renal surgery and PNL had been done in 410 (Group 2) and 131 (Group 3) patients, retrospectively. The mean operation time was longer (71.3 ± 33.5 min) in Group 2 and the mean fluoroscopy time was longer (8.6 ± 5.0) in Group 3 but there was no statistically significant difference between the groups. Highest stone clearance was achieved in primary PNL patients (81.62%) compared to the other groups (77.10% in Group 2 and 75.61% in Group 3). Stone-free rate was not significantly different between Group 2 and Group 3. Fever, pulmonary complications, and blood transfusion requirement were not statically different between groups but angioembolization was significantly higher in Group 2. Percutaneous nephrolithotomy is a safe and effective treatment modality for patients with renal stones regardless history of previous PNL or open renal surgery. However, history of open renal surgery but not PNL significantly reduced PNL success.

Does previous stone treatment in children generate a disadvantage or just the opposite?

In this study we aimed to determine the effects of previous open renal surgery, percutaneous nephrolithotomy and extracorporeal shockwave lithotripsy (ESWL) on the results and complications of subsequent percutaneous nephrolithotomy (PCNL) in pediatric patients. We reviewed the files of all 105 patients with 116 renal units (RU) undergoing PCNL at two main institutions between December 2000 and February 2014. The 116 RUs were divided into four groups: primary PCNL patients with 44 RU (37.9%) were categorized as group 1, 29 RU (25%) with a history of failed ESWL on the same side were categorized as group 2, 23 RU (19.8%) with previous PCNL surgery were categorized as group 3 and 20 RU (17.2%) with open renal surgery were categorized as group 4. Patient characteristics, mean operative time, mean fluoroscopy time, time to access the collecting system, hemoglobin change, number of more than 1 access, stone-free rates, postoperative hospitalization time and complications in four groups were compared. There were no differences between the groups in age, sex, mean stone size and stone laterality. Mean operative time, mean fluoroscopy time, time to access the collecting system, hemoglobin change, complication rates, number of more than one access hospitalization times were similar in the each group (p > 0.05 for each parameter). The stone-free rates after PCNL were 81.8% in group 1, 79.3% in group 2, 78.3% in group 3 and 80 % in group 4 (p = 0.67). Percutaneous nephrolithotomy is effective and safe in children who have previously had open nephrolithotomy, history of ESWL or PCNL without no more complications than are seen with primary PCNL of kidneys and with similar success rate.

Does previous open nephrolithotomy affect the outcomes and complications of percutaneous nephrolithotomy in children?

OBJECTIVE

To analyze the success and complication rates of percutaneous nephrolithotomy (PCNL) performed in pediatric patients and to compare outcomes of the patients undergoing primary PCNL with those of patients who had undergone previous open nephrolithotomy.

MATERIALS AND METHODS

Between 2000 and 2011, PNL procedures were performed in 123 renal units (RU) of 111 children. We compared RU on which previous open surgery had been performed (group 1 RU = 26) on the same kidney with RU that had not been involved in previous surgery (group 2 RU = 97). Patient characteristics, pre- and postoperative hematocrit and creatinin levels, operative time, fluoroscopic screening time, stone free rate, complications and hospitalization time were documented and compared.

RESULTS

There were no significant differences between the groups in sex, stone burden, pre- and postoperative hematocrit levels. Mean age and pre- and postoperative creatinin levels were significantly higher in group 1 (p < 0.05). Mean operative time, fluoroscopic screening time and hospitalization times were similar in each group (p > 0.05). The stone free rates after PCNL were 65.4% in group 1 and 81.4% in group 2 (p > 0.05). Multiple access rate was higher in group 1; however, this was not statistically significant (27% vs. 15%, p > 0.05).

CONCLUSION

PCNL can be performed in pediatric patients who have previously undergone open nephrolithotomy but the success rates may be lower and risk of bowel injury higher. NCCT should be considered preoperatively for patients who have previously undergone open renal surgeries to investigate the presence of retrorenal colons. Our study includes relatively few patients with a history of open surgery and we believe that additional clinical studies with larger numbers of patients are needed to confirm our initial findings.

Factors Influencing the Duration of Urine Leakage following Percutaneous Nephrolithotomy

Purpose. The duration of urine leakage following the removal of the nephrostomy tube after percutaneous nephrolithotomy (PCNL) shows significant variations depending on the techniques used. We aimed to assess the factors likely to influence the duration of urine leakage. Material and Methods. In total, 103 patients who underwent PCNL were reviewed retrospectively. DUL was evaluated regarding patient characteristics, thickness of the access line, presence of hydronephrosis, and residual stones. Results. DUL was significantly prolonged in accordance with a decrease in the thickness of parenchyma tissue (R = −0.716, P < 0.001). DUL was prolonged as the degree of hydronephrosis (R = 0.526, P < 0.001) and the number of patients with residual stones (R = 0.273, P = 0.005) increased. Median DUL was significantly longer in patients with residual stones than those without residual stones (P = 0.002). In the receiving operating curve analysis, the optimum cut-off value of parenchymal thickness for hospitalization ≤12 h was 17.2 mm (sensitivity, 90.2%; specificity, 69.4%; P = 0.001). Conclusions. We found that parenchymal thickness of the access line, hydronephrosis, and residual stones were the most influential factors determining DUL following PCNL, respectively.

Percutaneous nephrolithotomy for renal stones following failed extracorporeal shockwave lithotripsy: different performances and morbidities

The purpose of this study is to summarize the results of percutaneous nephrolithotomy (PCNL) for renal stones following failed extracorporeal shockwave lithotripsy (SWL), and to investigate the effect of previous SWL on the performances and morbidities of subsequent PCNL. Sixty-two patients with a history of failed SWL who underwent PCNL on the same kidney (group 1) were compared to 273 patients who had received PCNL as first treatment choice (group 2). Patient demographics, stone characteristics, operative findings, and complications were documented and compared. Groups 1 and 2 had similar patient demographics and stone characteristics. Mean time to establish access was comparable in both groups (10.5 ± 4.2 vs. 9.6 ± 4.5 min, p = 0.894). Time required to remove stones and total operative time were longer in group 1 (71.5 ± 10.3 vs. 62.3 ± 8.6 min, p = 0.011 and 95.8 ± 12.0 vs. 80.6 ± 13.2 min., p = 0.018, respectively). Group 1 had lower clearance rate compared to group 2 (83.9 vs. 93.4 %, p = 0.021), while postoperative complications were similar in both groups. Scattered stone fragments buried within the tissues made the procedure more difficult for stone fragmenting and extracting, which lead to longer operative time and inferior stone free rate. However, the PCNL procedure was safe and effective in patients with failed SWL. The risk of complications was similar and clearance rate was encouraging.

PCNL--A comparative study in nonoperated and in previously operated (open nephrolithotomy/pyelolithotomy) patients--a single-surgeon experience

PURPOSE

Re-procedure in patients with history of open stone surgery is usually challenging due to the alteration in the retroperitoneal anatomy. The aim of this study was to determine the possible impact of open renal surgery on the efficacy and morbidity of subsequent percutaneous nephrolithotomy (PCNL).

MATERIALS AND METHODS

From March 2009 until September 2010, 120 patients underwent PCNL. Of these, 20 patients were excluded (tubeless or bilateral simultaneous PCNL). Of the remaining 100, 55 primary patients were categorized as Group 1 and the remaining (previous open nephrolithotomy) as Group 2. Standard preoperative evaluation was carried out prior to intervention, Statistical analysis was performed using SPSS v. 11 with the chi-square test, independent samples t-test, and Mann-Whitney U test. A p-value < 0.05 was taken as statistically significant.

RESULTS

Both groups were similar in demographic profile and stone burden. Attempts to access the PCS was less in Group 1 compared to Group 2 (1.2 + 1 2 vs. 3 + 1.3 respectively) and this was statistically significant (p < 0.04). However, the mean operative time between the two groups was not statistically significant (p = 0.44). Blood transfusion rate was comparable in the two groups (p = 0.24). One patient in Group 2 developed hemothorax following a supra-11th puncture. Remaining complications were comparable in both groups.

CONCLUSION

Patients with past history of renal stone surgery may need more attempts to access the pelvicaliceal system and have difficulty in tract dilation secondary to retroperitoneal scarring. But overall morbidity and efficacy is same in both groups.

Factors affecting operative time during percutaneous nephrolithotomy: our experience with the complete supine position

BACKGROUND AND PURPOSE

Operative time influences surgical outcomes, operation-related and indirectly anesthesia-related complications. We investigated variables that affect operative time during percutaneous nephrolithotomy (PCNL) with the complete supine position.

PATIENTS AND METHODS

We reviewed data of 120 patients who underwent complete supine PCNL by one surgeon. Correlation between age, sex, body mass index (BMI), preoperative serum creatinine and hemoglobin levels, history (stone surgery, shockwave lithotripsy (SWL), hypertension, diabetes), stone (side, opacity, burden, complexity), imaging for access, calix for access, number of tracts, and tubeless approach with operative time were assessed by univariate and multivariate statistical tests.

RESULTS

Mean operative time was 60.62±30.70 minutes. In univariate analysis, age, sex, groups of BMI, hypertension, diabetes, previous stone surgery and SWL, stone opacity, operation side, number of tracts, and tubeless approach had no effect on operative time. BMI (P=0.029, negative correlation), stone burden (P=0.001, positive correlation), imaging for access (P=0.001, fluoroscopy<ultrasonography), calix for access (P=0.035, upper>lower>middle) and probably complex stones (P=0.057, complex>noncomplex) were effective factors on operative time. Multiple linear regression revealed association between BMI (P=0.000, negative correlation), stone burden (P=0.005, positive correlation), imaging for access (P=0.000, fluoroscopy<ultrasonography), and calix for access (P=0.023) with operative time. In lower calix access, mean operative time was less than upper calix access (P=0.022, significant) and higher than middle calix access (P=0.930, nonsignificant).

CONCLUSIONS

BMI, stone burden, imaging for access, and calix for access were effective parameters on operative time in complete supine PCNL. Groups of BMI, previous stone surgery and SWL, number of tracts, and tubeless approach had no effect on operative time.

Variables that influence operative time during percutaneous nephrolithotomy: an analysis of 1897 cases

BACKGROUND AND PURPOSE

Operative time is an important perioperative factor and is related to postoperative complications and procedural cost-effectiveness. There are few studies, however, investigating factors that affect operative time during percutaneous nephrolithotomy (PCNL). In this study, patient and kidney stone-related factors that influence operative time were analyzed.

MATERIALS AND METHODS

Clinical records from 1897 patients with renal calculi who underwent PCNL were retrospectively reviewed, and these patients were divided into two groups based on their median operative time (group 1: ≤60 min; group 2: >60 min). Multivariate analyses as well as univariate analyses including chi-square, Fisher exact and Mann Whitney U tests were used to investigate the effects of independent variables on operative time, including patient and kidney stone-related factors such as age, sex, body mass index, history of ipsilateral open surgery, shockwave lithotripsy, presence of hydronephrosis, stone burden, stone type and opacity, and surgical experience.

RESULTS

The mean operative time was 64.9±27.6 minutes (range 10-220 min). Univariate analyses determined that a history of open surgery, presence of hydronephrosis, stone type and size, and surgical experience correlated with operative time (P<0.05 for all). Multivariate analyses revealed that presence of hydronephrosis (odds ratio [OR]: 1.44, 95% confidence interval [CI]: 1.17-1.78, P=0.002), stone type (OR: 2.12, 95% CI: 1.69-2.70, P<0.0001), stone burden (OR: 2.44, 95% CI: 1.85-3.12, P<0.0001), and surgical experience (OR: 0.56, 95% CI: 0.46-0.70, P<0.0001) were significant independent factors in influencing operative time.

CONCLUSIONS

Presence of hydronephrosis, renal stone size and type significantly affect the operative time during PCNL. The duration of the operation was also observed to decrease with increased surgical experience.

Which factors may effect urinary leakage following percutaneous nephrolithotomy?

OBJECTIVE

To evaluate the factors that may effect urinary leakage following percutaneous nephrolithotomy (PCNL).

METHODS

Four hundred and thirty-three patients who underwent PCNL were reviewed retrospectively. The factors that may lead to leakage after surgery were analyzed as categorized into four groups according to individual variables (age, sex, body mass index); renal factors (previous surgery, extracorporeal shock wave lithotripsy history, presence of hydronephrosis); stone burden; and surgical features (access number, type of dilatation, presence of nephrostomy catheter). These data were compared for the presence and duration of urinary leakage.

RESULTS

There was no statistically significant correlation between individual factors and both the presence of leak (POL) and the duration of leak (DOL) (P > 0.05). Among renal factors, only presence and degree of hydronephrosis was significantly correlated with POL (P < 0.001) and DOL (P < 0.001). The mean cumulative stone burden neither had impact on POL nor correlated with DOL (P > 0.05). Among surgical factors, dilatation with a Nephromax dilator significantly increased incidence of POL when compared with an Amplatz dilator (P < 0.001), yet did not change DOL. Using an internal ureteral stent significantly decreased incidence of POL and DOL (P < 0.001). DOL increased with catheter diameter and stay time (P < 0.05).

CONCLUSION

Several yet simple factors appear to be effective in postoperative urine leakage from the access sites after percutaneous stone surgery. Precautions may also be simple if these factors are considered preoperatively.