Pediatric Percutaneous Nephrolithotomy Research Articles

Standard versus mini amplatz size in patients undergoing pediatric percutaneous nephrolithotomy through 16 years of experience: A retrospective study in single-center experience

Background: Pediatric urolithiasis is associated with considerable morbidity and a very high recurrence rate of approximately 67%. Current guideline recommendations for standard pediatric percutaneous nephrolithotomy (PCNL) remain a problem due to several complications, such as hemorrhage or renal damage, especially in the pediatric population. However, mini-PCNL is regarded as a safer and more effective method for pediatric patients. This study compares PCNL with mini-PCNL, along with their efficacy and safety, in the Cipto Mangunkusumo General Hospital, Indonesia. Methods: This observational retrospective study was performed on pediatric patients aged < 18 years (pediatric patients) who underwent PCNL with a standard 22-30 Fr sheath or mini 15-21 Fr sheath. We reviewed postoperative outcomes, including stone-free rate (SFR), presence of complications, and postoperative drainage method. Data analysis was performed using SPSS version 26.0. Results: Our study included a total of 42 pediatric patients (mean age: standard, 4.61 ± 3.52 years; mini, 8.0 ± 3.57 years; p<0.05). The stone-free rate was significantly higher in the mini-PCNL group (87.9%) than in the standard PCNL group (59.1%, p <0.05). All patients treated with mini-PCNL were tubeless, while some patients in the standard group still needed a postoperative drainage tube (p=0.012). Complications, such as infundibulum laceration, were rare, and their differences between groups insignificant (p=1). Even though it has been demonstrated that standard sheath PCNL is considered effective for children, smaller PCNL sheaths offers more experience. Mini-PCNL provides a similar complication rate, while remaining effective in treating urolithiasis; thus, it is thought to be a non-inferior option for treating pediatric populations, especially younger and smaller children. Conclusions: Mini-PCNL is non-inferior to standard PCNL in terms of efficacy and safety for the treatment of pediatric urolithiasis. Mini-PCNL resulted in higher SFR and totally tubeless follow-up.

Paediatric percutaneous nephrolithotomy (P-PCNL) reporting checklist.

To develop a reporting checklist that serves to improve and standardise reporting in studies pertaining to paediatric percutaneous nephrolithotomy (PCNL). Based on findings from systematic review of literature, a draft list of items was formulated. By process of review and revisions, a finalised version was established and consensus achieved. The finalised version of the checklist covers four main sections, which include the following areas: study details, pre-operative, operative and post-operative information. There are 18 further sub-items. Recommendations deemed to be of high importance to include are highlighted in bold. This practical tool can aid clinicians and researchers when undertaking and reviewing studies on paediatric PCNL. This is highly relevant given the current heterogeneity that exists as well as debate in best practice patterns.

Evaluation of the efficacy and safety of percutaneous nephrolithotomy in children

Background: Children represent 2-4.3% of the total population of stone formers. Currently, the majority of stones in children can be managed either with shock-wave lithotripsy (SWL), percutaneous nephrolithotomy (PCNL), ureterorenoscopy (URS), or a combination of these modalities. Open surgery is currently necessary in a few selected cases only. In our study, we wanted to evaluate the overall results of pediatric percutaneous nephrolithotomy (PCNL).Methods: This study was based on patients of age <14 years who underwent PCNL at Nizam’s Institute of Medical Sciences, Hyderabad, India from January 2019 to December 2020. This was a retrospective study. Children with >1 cm calculi were included and the exclusion criteria were stones of <1 cm, deranged renal functions, and bleeding disorders.Results: We performed 73 PCNL procedures on 65 children, achieved complete stone clearance in 93% and residual calculi (<10 mm) was seen following five cases; three patients underwent redo-PCNL. The complication rate in the present study was (16.4%) however, 100% of the total complications were minor i.e. Clavien score I and II, which were managed conservatively.Conclusions: Thus, PCNL is a suitable treatment option for children with nephrolithiasis as avoiding open surgery in children. Higher rates of failure and numerous sessions under anesthesia with short wave lithotripsy (SWL) makes it a non-viable option in children. RIRS is not widely available, non-affordable by many and long-term outcomes not clearly known with respect to ureteral strictures in children.

Single step track dilatation for percutaneous nephrolithotomy in children

Introduction and objectivesData on the use of single step dilatation technique during pediatric percutaneous nephrolithotomy (PCNL) in the literature is sparse. In this prospective randomized study, we aimed to compare the safety, efficacy, and perioperative complications of single step versus serial tract dilatation using Alken metal telescopic dilators during pediatric PCNL.MethodsPatients undergoing PCNL were randomized into two groups according to the dilatation technique used. In group A, Alken telescopic serial metal dilatation was utilized, and in group B, single step dilatation was performed. Inclusion criteria included children < 18 years with stone burden from 2 to 4 cm, located in the renal pelvis ± one calyx, who were candidates for PCNL.The primary outcomes were access time and complications’ rate. The secondary outcomes were dilatation fluoroscopy time, operative duration, stone free rate, postoperative hospital stay, hemoglobin deficit, and need for blood transfusion. Both outcomes were evaluated and compared between both treatment groups.ResultsA total of 70 patients were randomized into group A (35 patients) and group B (35 patients). Access was successfully obtained in all procedures. All the procedures were performed through a single tract.Access time and dilatation fluoroscopy time were shorter in group B (statistically significant). Patients in group A had higher rate of complications (statistically significant). Intraoperative bleeding requiring blood transfusion was less in single track dilatation than serial metal track dilatation.ConclusionsCompared to serial metal track dilatation, single step dilatation showed comparable operative time and stone free rate, with significantly reduced access time and dilatation fluoroscopy time.

The feasibility of one-day length of hospital stay after pediatric percutaneous nephrolithotomy.

To evaluate the safety of one-day length of hospital stay (LOS) after pediatric percutaneous nephrolithotomy (PNL), and to study the predictors of LOS. A retrospective study included pediatric patients who PNL for renal calculi more than 1 cm between January 2016 and October 2019. PNL was performed in prone position. The nephrostomy tubes and ureteric catheters were removed on the second day and patients were discharged if there was no perforation or significant residual stones. The stone free rate, LOS and the surgical complications were reported. Bivariate and multivariate analysis were used to predict the LOS. 220 patients were identified. The median age (range) was eight (Range: 3-17) years. Stone free rate was achieved in 200 patients (91%) of patients, while residual fragments were detected in 20 patients (9%). Complications, they were reported in 50 (22.7%) patients. 184 (83.6%) of patients stayed at the hospital for only 1 day, while 36 (16. 4%) stayed more than 1 day. Of 36 patients who stayed more than one-day, 34 had complications (p value <0.001).On multivariate analysis, surgical complications was found to be the only predictor of longer LOS (p value <0.001). Early nephrostomy tube removal and 1-day length of hospital stay could be a safe option after pediatric PNL. Surgical complications is a statistically significant predictor of longer LOS.

Which factors affect the success of pediatric PCNL? Single center experience over 20 years.

We aimed to investigate the impact of surgeons' experience on pediatric percutaneous nephrolithotomy (PCNL) outcomes. Between June 1997 and June 2018, 573 pediatric patients with 654 renal units underwent PCNL for renal stone disease by senior surgeons. Data were divided into two groups, group-1 (n = 267), first ten years period, group-2 (n = 387); second ten years period. Mean ± SD age of patients was 7.6 ± 4.9 (1-17) years. The stone-free rates (SFR) assessed after 4 weeks were 74.9% vs. 83.4% in group-1 vs. group-2, respectively (p = 0.03). The mean operation time, fluoroscopy time, and the number of patients requiring blood transfusion significantly decreased in group 2 (100.4 ± 57.5 vs. 63.63 ± 36.3, 12.1 ± 8.3 vs. 8.3 ± 5.4, and 24.3% vs. 2.9%; p < 0.001, p < 0.001, and p = 0.002 in group-1 versus group-2, respectively). On multivariate analysis, increasing stone size increased operation time (p < 0.001), fluoroscopy time (p < 0.001), intraoperative and postoperative blood transfusion rates (p = 0.006 and p = 0.018, respectively), and hospital stay (p = 0.002) but was not associated with change of glomerular filtration rate (GFR) (p = 0.71). Sheath size also correlated with increased fluoroscopy time (p < 0.001), operation time (p < 0.001), intraoperative blood transfusion (p < 0.001) and hospital stay, but sheath size did not affect postoperative blood transfusion (p = 0.614) or GFR change (p = 0.994). The percutaneous nephrolithotomy (PCNL) is a minimally invasive procedure and is well accepted because of its lower complication rate and high efficiency for pediatric patients. Stone and sheath size are predictive factors for blood loss and hospital stay. During 20 years, our fluoroscopy time, operation time, blood loss, and complication rates decreased, and stone-free rate increased.

Pediatric Percutaneous Nephrolithotomy in a Peripheral Tertiary Care Center in Nepal

Introduction Pediatric nephrolithiasis though uncommon, poses clinical management dilemma due to anatomical and physiological factors. Percutaneous Nephrolithotomy (PCNL) is well established in adults and miniaturization of the instruments has helped to expand its indication for uses in pediatric population with equivalent results. The aim of our study is to evaluate the application of the procedure in our settings.&#x0D; MethodsThis was a retrospective study done at Nepalgunj Medical College teaching hospital from June 2017 to April 2020. Total of 75 patients with 76 renal units under 18 year of age were evaluated. PCNL was done in prone position in all patients using fluoroscopy for initial puncture and subsequently for clearance. The size of the tract varying from 15 Fr to 24 Fr was decided based on the degree of hydronephrosis.&#x0D; ResultsMean stone volume was 372 mm2. With mean operative time of 58 min, 96% of stone clearance rate was achieved. Mini PCNL was done in most of the cases. Single tract was used in 84% cases mostly with subcostal puncture. Major complications were pelvic perforation in 4% cases and two patients required restaging.&#x0D; ConclusionPCNL in pediatric population is safe with good stone free rate with minimal complications. Application of miniaturized instruments has further improved the outcome with comparable morbidity.

Fluoroscopic imaging optimization in children during percutaneous nephrolithotrispy

Radiation protection management recommends radiation exposures that are as low as reasonably achievable (ALARA), while still maintaining image quality. The aim of the study is to compare radiation exposure during pediatric percutaneous nephrolithotomy (PCNL) before and after implementation of strategy for optimization of fluoroscopic imaging by measuring the Dose Area Product (DAP) and the Fluoroscopy time (FT) and study its effect on surgical outcomes. We prospectively observed 56 children (group 1) undergoing PCNL for kidney stones in whom a radiation dose reduction strategy was adopted. The strategy included several intraoperative measures, including: optimizing position by keeping the fluoroscopy table as far from the X-ray tube as possible and the image intensifier close to the patient, preventing use of fluoroscopy for positioning, use of pulsed mode with last image hold technique, beam collimation and use of a designated fluoroscopy technician. Outcomes were compared to those in 42 children (group 2) before implementing dose reduction strategy. DAP was decreased by 44% from 2.46 in group 2 to 1.38mGy m2 in group 1 (p<0.04). Total fluoroscopy time was significantly reduced by 55% from 100.8s in group 2-45s in group 1 (p<0.002) after protocol implementation with very little loss of image quality. Radiation exposure in children undergoing PCNL can be reduced significantly after optimization of fluoroscopy imaging. A reduced radiation protocol did not increase surgical complexity, operative time, or complication rates while reducing radiation exposure in a population vulnerable to its hazardous effects.

747 - Evolution of single center experiences in pediatric percutaneous nephrolithotomy over 20 years

747 - Evolution of single center experiences in pediatric percutaneous nephrolithotomy over 20 years

Safety and efficacy of percutaneous nephrolithotomy in paediatric age group: our 3 year experience in Western Rajasthan

Background: Percutaneous nephrolithotomy (PCNL) has become a well-established procedure for the management of pediatric renal calculi. Paediatric PCNL has been performed using both adult and paediatric instruments. Objectives: To evaluate the safety, efficacy and complications using the Modified Clavien scoring system (MCSS) in children undergoing PCNL using adult sized instruments.Methods: All patients less than 16 years old were analyzed retrospectively in Western Rajasthan undergoing PCNL procedure at Dr. SN Medical College and Hospital from April 2016 to March 2019. All PCNL procedures were performed in prone position under general anaesthesia with fluoroscopic guidance and using adult size instruments. All the demographics, surgical data and perioperative information were collected.Results: Total 112 patients with 120 renal units (8 patients with bilateral stones), (66 boys and 46 girls), with a mean (range) age was 10.01±4.02 (2-16) years. The mean (range) stone size in our study was 28.94±1.10 (20-50 mm). Overall, stone-free rate after PCNL was 95%. Twenty five (25) children (20.8%) had operative complications; 23/25 (92%) had, Clavien grade I in 15 (60%), grade II in 8(32%) and all managed conservatively. 2 patients had hydropneumothorax, managed with ICD tube. Stone size, operative duration and haemoglobin drop were significantly associated with complications on Univariate analysis (p&lt;0.05).Conclusions: In paedriatric age group PCNL is considered safe with MCSS showing grade I and grade II complications in majority (92%) of patients.

The Success of Pediatric Percutaneous Nephrolithotomy

The Success of Pediatric Percutaneous Nephrolithotomy

Local Anesthetic Infiltration During Pediatric Percutaneous Nephrolithotomy Improves Postoperative Analgesia

Local Anesthetic Infiltration During Pediatric Percutaneous Nephrolithotomy Improves Postoperative Analgesia

Can single-step dilatation technique in pediatric percutaneous nephrolithotomy be an effective alternative to stepwise dilatation?

Aim: The most important stage of percutaneous nephrolithotomy (PNL), which is an effective and reliable method in the treatment of large and complex kidney stones, is to create a suitable and effective tract after the accessory is provided. For this purpose, different techniques such as Amplatz, baloon and Alken dilators have been described. We aimed to compare the efficacy and safety of single-step Amplatz dilatation technique with stepwise Amplatz dilatation technique in pediatric PNL patients. Methods: This is a retrospective cohort study. We evaluated the data from 75 PNL operations performed on 72 pediatric patients in our center within the last decade. The data from single-step dilation technique patient group (group 1, n: 41) and the stepwise dilatation technique patient group (group 2, n: 34) was compared in terms of durations of fluoroscopy and surgery, stone-free and complication rates, pre and postoperative hematocrit levels and blood transfusions rates. Results: There was no significant difference between the groups in terms of demographic data, mean stone burden, duration of surgery, decrease in hematocrit, blood transfusion rates, stone-free rate and complication rates. The median fluoroscopy durations of group 1 and group 2 were 120 and 220 seconds, respectively. Duration of surgery and fluoroscopy were significantly shorter in the single-step dilatation group Conclusion: PNL is a safe and effective procedure for pediatric stone diseases. Performing this procedure with a single-step dilatation technique ensures that children are less exposed to radiation.

A new simple scoring system for prediction of success and complication rates in pediatric percutaneous nephrolithotomy: stone-kidney size score

Nomograms and scoring systems designed for predicting the success of percutaneous nephrolithotomy (PCNL) in adults are currently available. However, no scoring system currently exists primarily for predicting PCNL success in children. The objective of this study was to develop a scoring system to predict the stone-free and complication rates by using pre-operative parameters. A retrospective analysis was conducted on data from 434 renal units belonging to patients with kidney stones who underwent PCNL between 1997 and 2017. Renal stone index was calculated by dividing the length of the stone along its longest axis by the length of the kidney along its longest axis. Guy's Stone scores, S.T.O.N.E scores, and CROES scores for adults were calculated by filling in the variables for each patient. Factors that predicted success and complications were examined by univariate and multivariate analyses. Mean age was 8.3 (1-16) years, and male to female ratio was 236:165. When stone-free patients were compared with other patients, there was a statistically significant difference in the average stone/kidney index (SKI) value (stone size/kidney size on longitudinal axis) (0.266 vs 0.339, P<0.001). In multivariate analysis, factors that predicted success were the SKI and number of stones. A newly developed scoring scale, the stone-kidney score (SKS), combined scores for both the SKI and the number of stones into one value. A minimum total SKS score was 2, and a maximum total SKS score was 4. Success rates for SKS scores of 2, 3, and 4 were 86.4%, 73%, and 62.9% (P<0.001), respectively. Complication rates for SKS scores of 2, 3, and 4 were 13%, 22.1%, and 23.8%, respectively. The new scoring system has only two variables (number of stones and SKI) and three risk groups. An SKS score is easier to use and calculate. An SKI value can be simply calculated on any imaging modality by dividing the length of the stone along its longest axis by the length of the kidney along its longest axis. As in the new scoring system, the SKI value combined with the number of stones is useful in predicting stone-free rates after PCNL. When evaluated together, the SKI and presence of multiple stones may predict stone-free rates pre-operatively. The SKS is an individual-specific method that can be easily used in pediatric clinical practice. Further studies are required to develop and standardize this method.

Percutaneous Nephrolithotomy in Children: Analysis of Nationwide Hospitalizations and Short-Term Outcomes for the United States, 2001-2014.

To describe population-wide utilization rates and outcomes of percutaneous nephrolithotomy (PCNL) in the management of pediatric upper urinary tract calculi (UUTC). Patients <18 years with a diagnosis of UUTC, who underwent PCNL between 2001 and 2014 were identified from the National Inpatient Sample database. Annual PCNL rates, based on the at-risk population for each year, were estimated, and change in utilization rate was analyzed using negative binomial regression. Perioperative outcomes, hospital length of stay (LOS), and costs were determined; continuous and categorical variables were analyzed using nonparametric tests and Chi-squared tests, respectively. Trends tests and multivariable analyses (MVAs) were also performed where appropriate. An estimated 3206 pediatric PCNL procedures were performed. Mean annual PCNL rate increased significantly relative to 2001 (incidence rate ratio = 1.40; 95% confidence interval 1.15-1.71, p = 0.001). Proportion of PCNL as a fraction of all inpatient surgical procedures for UUTC also significantly increased over time, from 15.7% in 2001 to 26.4% in 2014 (p < 0.0001). Complications overall occurred in 20.7% of cases, with a significantly rising rate over time period (p < 0.0001). Complication rates were similar across hospital types and geographic regions. Median hospitalization cost was significantly higher for the West than for each of the other regions (p < 0.05 in each case). Median LOS was also highest for the West (4 days vs 3 days for each of the other regions). In MVA, significant predictors of both increased LOS and costs included black race, comorbidities of hypertension, diabetes, coagulopathy and neurologic disease, hospitalization in the South, and presence of complications. Race, gender, comorbidities, and treatment year were among the predictors of complications. PCNL utilization in the management of pediatric UUTC has significantly increased since 2001, with an associated increase in complication rates, although major complications were uncommon. Regional variations in costs and LOS were evident.

Predicting surgical outcome of pediatric percutaneous nephrolithotomy

Purpose: The aim was to evaluate the outcome of pediatric percutaneous nephrolithotomy (PCNL) guided by Guy’s stone score grading system. Patients and methods: This was a prospective study of children with renal calculi more than 2 cm. They were younger than 18 years and were a candidate for PCNL at our University Hospitals from January 2013 until July 2016. All of them had a low-dose noncontrast enhanced computed tomography. The procedure was performed under general anesthesia with the patients in the prone position guided by fluoroscopy. The stone-free rate and the presence and type of complications were estimated. The demographic and clinical data, stone characteristics, radiologic anatomy as well the PCNL approach and methods of lithotripsy used were evaluated. Comparison was performed through using univariate and multivariate analyses, and factors predicting the PCNL outcome were determined. Results: A total of 110 children with kidney stones were accepted for PCNL. Overall, 95 (86.3%) of 110 children were stone free after one-stage PCNL. Grade 1 Guy’s stone score was 97.5% (40/41) ( P <0.05). Mean hospital stay was 4.01 ± 2.0 days. Operative complications include bleeding in 12 (10.9%), extravasation in seven (6.4%), injury to the colon in one (0.9%), and renal pelvis perforation three (2.7%). In our study, larger Amplatz sheath, stone burden, and longer operative time are related to complications. Conclusion: Guy’s stone score correlated with both success and complications and can be used for decision making preoperatively in pediatric PCNL. Keywords: Guy’s stone score, minimally invasive, percutaneous nephrolithotomy, pediatric, urolithiasis

Renal stone composition does not affect the outcome of percutaneous nephrolithotomy in children.

We sought to investigate the association between renal stone composition and percutaneous nephrolithotomy outcomes in pediatric patients and define the characterization of the stone composition. The data of 1157 children who underwent percutaneous nephrolithotomy between 1991 and 2012 were retrieved from the multicenter database of the Turkish Pediatric Urology Society. The study population comprised 359 children (160 girls, 199 boys) with stone analyses. Patients were divided into five groups according to the stone composition [group 1: calcium oxalate; group 2: calcium phosphate; group 3: infection stones (magnesium ammonium phosphate, ammonium urate); group 4: cystine; group 5: uric acid, xanthine stones]. Patient characteristics, perioperative, postoperative, and stone characteristics were compared considering the stone composition. There were no significant differences between the groups concerning age, sex, side involved, preoperative hematocrit levels, and solitary renal unit. Patients with cystine stones were more likely to have a history of stone treatment. Groups 2 and 5 had mostly solitary stones. However, group 3 had staghorn stone more often, and group 4 frequently had multiple stones. Overall stone-free rate (79.4%) was similar among the groups. Although stone composition was related to blood transfusion and prolonged operative and fluoroscopy screening times on univariate analysis, it was not a significant predictor of them on multivariate analysis. Stone composition was not a predictor of outcomes of pediatric percutaneous nephrolithotomy. However, cystine and infection stones, which are larger and filled multiple calyxes due to the nature of stone forming, were more challenging cases that need multiple tracts.

Factors predicting postoperative febrile urinary tract infection following percutaneous nephrolithotomy in prepubertal children

Predictive tables and scoring systems can predict stone clearance. However, there is a paucity of evidence regarding the prediction of complications during percutaneous nephrolithotomy (PCNL), particularly in children, which remains under-researched. To our knowledge, no studies have evaluated the risk factors for febrile urinary tract infection (FUTI) after pediatric PCNL. To assess the predictive factors of FUTI in prepubertal children after PCNL and determine whether any prophylactic cephalosporins are superior for decreasing the FUTI rate. Data from 1157 children who underwent PCNL between 1991 and 2012 were retrieved from the multicenter database of the Turkish Pediatric Urology Society. Children >12 years of age were excluded, leaving 830 children (364 girls, 466 boys). Data were analyzed according to the presence of FUTI and compared between the FUTI and non-FUTI groups. Mean age was 6.46±3.38 years. Twenty-nine (3.5%) children had FUTI which was confirmed by urine culture. FUTI occurred more frequently in young children (5.5%) than school-age children (2.4%). In univariate analysis, there were significant differences between the FUTI and non-FUTI groups regarding age, cephalosporin subgroup (first, second and third generation cephalosporin), side of PCNL, staghorn stones, tract size, operative time, postoperative ureteral catheter usage, perioperative complications (SATAVA), and blood transfusion. Multivariate analysis revealed that age, side of PCNL, staghorn stones, tract size, operative time, and blood transfusion were independent predictors of FUTI. The smaller tract size could cause FUTI with poor fluid drainage that may lead to elevate renal pelvic pressure and trigger bacteremia-causing pyelovenous backflow. Filling the calyx and renal pelvis by a staghorn stone and the resulting obstruction of fluid drainage may elevate intrarenal pelvis pressure. Longer operative time is likely to increase renal pelvic pressure over longer periods, which may account for FUTI after pediatric PCNL. Younger age, right-sided PCNL, staghorn stones, mini-PCNL, longer operative time, and blood transfusion are risk factors for FUTI. First-, second-, and third-generation cephalosporins are equally effective for prophylaxis in prepubertal children undergoing PCNL.

Predictive ability of Guy's stone score in pediatric patients undergoing percutaneous nephrolithotomy

Several authors have evaluated, in a number of external validation and predominantly adult studies, Guy's stone score (GSS) as a predictive tool for the assessment of stone clearance after percutaneous nephrolithotomy (PCNL). However, there are limited and conflicting data investigating whether GSS could be a potential independent factor associated with residual stone rates and complications of PCNL for children. The aim of the current study was to evaluate the ability of GSS, as an independent factor, to predict residual stone rates and complications in pediatric patients undergoing PCNL. The records of the pediatric patients who had undergone PCNL for stone disease at the current department were retrospectively reviewed. Variables included patient, stone, and treatment parameters. The GSS was used for assessment of stone complexity. Univariate and multivariate analyses were performed to evaluate factors associated with residual stone rates and complications of pediatric PCNL. The study group consisted of 114 children (63 boys and 51 girls) with a median (interquartile range) age of 6 (3-11) years and who had undergone 122 PCNLs (eight bilateral). Multivariate logistic regression analysis (Summary Table) demonstrated that the independent risk factors for increased residual stone rate following pediatric PCNL monotherapy were GSS (OR 3.14, 95% CI 1.31-7.49, P=0.01) and number of calyces involved (OR 4.02, 95% CI 1.11-14.53, P=0.033). Multivariate logistic regression analysis demonstrated that the independent risk factors for complications following pediatric PCNL were surgical experience (OR 2.72, 95% CI 1.09-6.82, P=0.032), and operation time (OR 1.01, 95% CI 1.00-1.03, P=0.040). A prediction model is needed to pre-operatively counsel patients and evaluate outcomes for measuring treatment success of PCNL. The GSS provides a simple, reliable and reproducible tool for describing the complexity of PCNL while predicting postoperative stone-free status, despite its limitations. However, little research has been conducted on the applicability of GSS in pediatric patients undergoing PCNL. In addition, conflicting results have been reported about its association with complications of pediatric PCNL. The current study found that although GSS had a significant predictive ability for residual stone rates after pediatric PCNL revealed by multivariate logistic regression, the results did not conclude that complexity of GSS was directly proportional to complications of pediatric PCNL. The factors, including calyceal involvement and surgeon experience, may need to be incorporated in GSS to further improve its ability to predict outcomes of pediatric PCNL. 1422.

Factors Affecting the Success Rate of Percutaneous Nephrolithotomy in Paediatric Patients.

In this study, we aimed to determine factors affecting the success rate of percutaneous nephrolithotomy (PNL) in children. The series consisted of 41 consecutive children operated on by the same surgical team for renal calculi with PNL between June 2002 and May 2015 in our institution. A single calyx or pelvic stone was described as simple, while calculi located in more than one location (calyx and pelvis or more than one calices) or staghorn stones were described as complex. The procedure was deemed successful if the patient was completely stone-free (SF) or had residual fragments <4 mm. Thirty-four patients were found to be SF or had residual fragments <4 mm on the postoperative first day, thus the success rate was 82.9%. In complex stones, the success rate was significantly lower (45.5%) than simple stones (96.7%) (p < 0.001). The grade of hydronephrosis (Grade 0–1 vs. Grade 2–3) also had a negative impact on the success, with rates of 92.6% vs. 64.3%, respectively (p = 0.022). Previous urological procedure history on the same side yielded a success rate of 58.3%, whereas the success rate in the primary patients was 93.1% (p < 0.001). The localization of the stone (complex vs. simple), degree of hydronephrosis, and history of previous urological procedures were found to be the factors that affected the success of the paediatric PNL.