Percutaneous Nephrolithotomy In Children Research Articles

Percutaneous Nephrolithotomy in Children with Cystine Stone: Long-Term Outcomes from a Single Institution

We determined the effectiveness of percutaneous nephrolithotomy in children with cystine stones and present the long-term outcomes. We reviewed the data of 65 renal units in 51 children who underwent percutaneous nephrolithotomy for cystine stones between 2000 and 2012. Of the patients 19 (37%) had undergone ipsilateral renal surgery and 11 (22%) had undergone extracorporeal shock wave lithotripsy. Children were designated as being stone-free or having residual stone (any evidence of persistent stone fragments irrespective of size). Medical treatment with α-mercaptopropionylglycine, potassium citrate or potassium sodium hydrogen citrate was recommended for all patients after stone analysis. Median stone burden was 3.3 cm(2) (range 1 to 13) and median patient age was 6 years (1 to 17). Stone-free status was achieved in 41 renal units (63.1%). Stone-free status was increased to 73.8% with additional endoscopic procedures. The remaining patients with residual stones were followed. Complication rate was 15.4%. A total of 35 children (68.6%) receiving regular medical treatment were followed for a median of 95 months (range 6 to 136). The recurrence rate for children achieving stone-free status was 31.2%, and the regrowth rate for children with residual stones was 29.4%. Percutaneous nephrolithotomy is a safe and effective treatment for children with cystine stones. Our high recurrence and regrowth rates emphasize that our treatment schedule is inadequate to prevent recurrent cystine calculi. Additional investigation is needed to determine the optimal medical therapy for preventing recurrence and regrowth of cystine stones.

Percutaneous nephrolithotomy in children in different age groups: data from the Clinical Research Office of the Endourological Society (CROES) Percutaneous Nephrolithotomy Global Study

To present the overall results of paediatric percutaneous nephrolithotomy (PCNL) compared with adults. To present the indications, complications and outcomes of patients treated in the participating centres in the PCNL Global Study, as categorised in different age groups. The Clinical Research Office of the Endourological Society (CROES) Study was conducted from November 2007 to December 2009, and included 96 centres and >5800 patients. All children aged ≤14 years in the PCNL Global Study database were the focus of the study. In all, 107 children aged ≤14 years were included in the analysis. The PCNL procedure was conducted in 13 patients (12.1%) in the supine position; tubeless PCNL was performed in 15 patients (14%); and balloon dilatation was preferred in 22 patients (20.5%). The overall mean operative duration was 97.02 min; blood transfusion rate, fever and stone-free rates were 9%, 14% and 70.1%, respectively. A comparison of the paediatric PCNL cases according to age groups showed no statistically significant differences between the subgroups for patient characteristics, co-morbidities, renal anomalies, or previous surgical history. In the evaluation of the operative details, the mean sheath size and nephrostomy tube size were larger in school-age children than the preschool children (P = 0.01 and 0.002, respectively). There was a difference in the preferred methods for confirming stone-free status, with ultrasonography preferred more in preschool children (P < 0.001). The PCNL procedure position, puncture site, dilatation method, postoperative tube application, and surgical outcomes were comparable in school- and preschool-age children. While operative details showed some differences between children and adults, the surgical outcomes were comparable. A considerable number (45.7%) of the paediatric patients had a previous history of stone intervention. Based on the findings of the present study, we can suggest that PCNL can be applied safely and effectively in children in different age groups. Outcomes appear comparable with those in adults for the success and complication rates, in the presence of substantial indications, appropriate equipment and adequate experience.

Complications and Associated Factors of Pediatric Extracorporeal Shock Wave Lithotripsy

We determined the safety, efficacy and complications of extracorporeal shock wave lithotripsy in managing pediatric urolithiasis and analyzed possible factors affecting the complication rate. We retrospectively reviewed 128 patients younger than 16 years who had undergone extracorporeal shock wave lithotripsy with a Lithostar® lithotripter between January 2000 and December 2010. Stone clearance and complications were assessed at postoperative week 1, and months 1 and 3. Success was defined as no radiological evidence of stone, or fragments 4 mm or less. Treatment failure was analyzed to find any correlation with stone size. Complications were assessed with a specific focus on rehospitalizations during postoperative week 1. The overall success rate was 93.5% (115 of 123 patients). Repeat treatment rate was 56.1% (69 patients). Extracorporeal shock wave lithotripsy failed in 8 children, who subsequently required ancillary procedures. Mean stone size in the treatment failure group was 17.03 mm, compared to 13.04 mm in the successfully treated group. A total of 22 patients (17.8%) had complications in postoperative week 1 but only 19 (15.4%, 12 boys and 7 girls) were rehospitalized at that time. Presence of a metabolic risk factor was the only predictive factor for complications. By comparison, we found a lower success rate and higher ancillary procedure rate in the group with complications. Extracorporeal shock wave lithotripsy is effective for pediatric urolithiasis, with a small but substantial morbidity rate. Parents should be informed about possible rehospitalization following extracorporeal shock wave lithotripsy due to complications independent of stone size.

1030 Percutaneous nephrolithotomy in children in different age groups

1030 Percutaneous nephrolithotomy in children in different age groups

Re: Efficiency of percutaneous nephrolithotomy in pediatric patients using adult-type instruments

We read the retrospective study comparing the outcomes of percutaneous nephrolithotomy (PCNL) in pediatric patients with great interest [1]. The authors have performed the procedure with 19F, 24F and 30F nephroscopes and 20F– 30F Amplatz sheath in all children. They performed the operations in prone position under fluoroscopy guidance. The study has shown that PCNL in children using adulttype instruments is safe and effective. Since the initial report by Woodside et al. [2], PCNL has come to be accepted as a well-established, minimally invasive procedure in children as well as adults. However, few centers have reported their experiences of PCNL in infants and very young children. PCNL with adult-size instruments may present problems in infants and preschool age children because of small size and mobility of the pediatric kidney, friable renal parenchyma, and the small size of the collecting system [3]. The authors have used the adult sized nephroscopes in this study. It might be well accepted to use single size equipment for all adults but this approach is not realistic for children. Children with a large stone burden and dilated collecting systems are good candidates for adult sized equipment. When the collecting system is not dilated, the instruments used in adults may be more traumatic because of their size. Additionally preschool age children have mobile and small size kidney. In our clinic, we use pediatric sized instruments in preschool children and older children with small stone burden or not dilated collecting system. The radiation exposure is an important concern in pediatric cases. Most of the urologists prefer to establish the access by themselves under fluoroscopy as in this study. We routinely use lead aprons under the child patients located between the X-ray tube and patient, except for abdomen, for radiation protection. We believe and suggest that this prevents the harmful effects of radiation on gonads and vital organs [4]. We think that, with experience, using a gentle technique, avoiding manipulations such as levering the nephroscope, and usage of flexible endoscopes and nitinol basket when necessary are important to increase the stone-free rate in PCNL. Also we believe that a holmium laser and nitinol basket catheter can be used through flexible nephroscope for locations unreachable using the rigid instruments. These manipulations might lower residual stone with higher stone-free rate in pediatric PCNL. Another potential complication of percutaneous nephrolithotomy is hypothermia, especially in this age group. Hypothermia during anesthesia produces potentially severe complications such as impaired platelet function and coagulation, decreased drug metabolism, increased wound infection rate and cardiac arrhythmias, and prolonged postanesthesia unit stay. We believe that warm air insufflators, electrical carpets, increased room temperature and warm infusion fluid are helpful to avoid hypothermia during PCNL.

UP-02.053 Percutaneous Nephrolithotomy in Children by Using Adult Size Instruments: 3 Years' Experience

UP-02.053 Percutaneous Nephrolithotomy in Children by Using Adult Size Instruments: 3 Years' Experience

Percutaneous nephrolithotomy in children: does age matter?

To compare the outcomes of percutaneous nephrolithotomy (PCNL) in 2 age groups. Fifty-one renal units (RU) of 45 patients were operated between January 2006 and December 2010. In all patients, PCNL was performed by pediatric nephroscope of 17F size through a 20F Amplatz sheath. Patients were examined in 2 groups (Group1: ≤5 years, Group 2: >5 years) and outcomes were compared accordingly. The mean age was 5.95 ± 3.63 years and male-to-female ratio was 23/22. The mean stone burden, operative time, and postoperative hospital stay were 4.24 ± 2.03 cm(2), 94.30 ± 37.28 min, and 5.18 ± 2.97 days, respectively. In the postoperative period, 44 renal units (86.2%) were stone-free. Two age groups were similar regarding the postoperative hospital stay, gender distribution, stone location, stone composition, and complication rates. However, stone burden and number of access was less and stone-free rate was higher in younger age group. The stone-free rate in preschool children is at least as good as older children without an increase in complication rates. The older children (>5 years) have a higher stone burden and need multiple accesses more frequently. The complications are mostly low grade and can be managed conservatively. Our results showed that PCNL in younger children as safe and effective as in the older children and age should not be considered as a limiting factor.

Successful Percutaneous Nephrolithotomy in Children: Multicenter Study on Current Status of its Use, Efficacy and Complications Using Clavien Classification

In this multicenter study we aimed to evaluate the efficacy and safety of percutaneous nephrolithotomy in children with respect to different features and using the Clavien classification system. Percutaneous nephrolithotomies performed in children at 3 urology departments between March 2006 and May 2010 were included in the study. Results are presented for complex/simple renal stones, tubeless/totally tubeless percutaneous nephrolithotomy, simultaneous bilateral percutaneous nephrolithotomy, instrument size and age groups. Patients were divided into 3 distinct groups, infants and toddlers (3 years or younger, group 1), preschool children (4 to 7 years, group 2) and school children (8 to 16 years, group 3). Perioperative complications are presented according to the modified Clavien classification system. A total of 140 percutaneous nephrolithotomies were performed in 130 patients (41.5% female, mean age 10.17 years). There were 23, 25 and 92 renal units in groups 1, 2 and 3, respectively. Pediatric instruments were used in 60 renal units and adult-sized instruments in 80. General assessment of complications showed Clavien grade I complications in 17 patients, II in 4, IIIa in 11 and IIIb in 7. There were no grade IV or V complications. Percutaneous nephrolithotomy can be applied safely in children of varying ages, even infants. Complications, as assessed with Clavien classification, are comparable to those seen in adults provided there is enough experience with the technique.

Percutaneous Nephrolithotomy in Children

The surgical management of pediatric stone disease has evolved significantly over the last three decades. Prior to the introduction of shockwave lithotripsy (SWL) in the 1980s, open lithotomy was the lone therapy for children with upper tract calculi. Since then, SWL has been the procedure of choice in most pediatric centers for children with large renal calculi. While other therapies such as percutaneous nephrolithotomy (PNL) were also being advanced around the same time, PNL was generally seen as a suitable therapy in adults because of the concerns for damage in the developing kidney. However, recent advances in endoscopic instrumentation and renal access techniques have led to an increase in its use in the pediatric population, particularly in those children with large upper tract stones. This paper is a review of the literature focusing on the indications, techniques, results, and complications of PNL in children with renal calculi.

Totally Tubeless Percutaneous Nephrolithotomy: Is It Safe and Effective in Preschool Children?

After the introduction of tubeless percutaneous nephrolithotomy (PNL), many studies conducted in adult patients have confirmed its efficacy and safety. There are limited studies reporting that tubeless PNL can be safely applied in children, however. Furthermore, there are no reports that evaluate the use of totally tubeless PNL in children. The present study evaluates the results of totally tubeless PNL in preschool children. The data of children seen in our clinic who were considered suitable for totally tubeless PNL were analyzed. Of 16 children, 8 patients underwent totally tubeless PNL (group 1) and 8 standard PNL (group 2). The two groups of patients were compared with regard to length of hospitalization, analgesic requirements, transfusion rates, hemoglobin (Hb) decrease, and immediate, early, and late complications. The mean ages of the patients were 56.6 months (9-84 mos) and 56.0 months (5-84 mos), and the mean follow-up was 21.5 months (3-44 mos) and 43.4 months (36-54 mos) in groups 1 and 2, respectively. Both groups were similar with regard to age, stone size, Hb change, and complications. Although operation duration, hospitalization period, and analgesic requirement were less in the totally tubeless PNL group, these differences were not statistically significant. The latest application of PNL, totally tubeless PNL, is also a safe and effective procedure in very small children if they are selected properly and if the surgeon has sufficient experience with the procedure. More studies with a higher number of participants are needed, however, to confirm that totally tubeless PNL increases the comfort of pediatric patients, decreases their hospitalization period, and is more economical.

Outcome of Percutaneous Nephrolithotomy in Children Having Complex Stones

Objectives: To review our experiences with percutaneous nephrolithotomy in children with complex renal calculi. Patients and Methods: We retrospectively analyzed the records of 31 children with complex renal calculi who were treated by percutaneous nephrolithotomy at 2 hospitals of our university between June 2003 and June 2008. The mean age of the patients was 10.4 years (range 22 months to 15 years). Three patients were aged ≤5 years. Stone clearance and complications were recorded. Results: The mean operating time (time from insertion of the ureteral catheter to placement of a nephrostomy tube) was 87.4 (range 50–180) min. In 2 patients the procedures were staged because of a large residual stone load. The extent of percutaneous tract dilation was undertaken taking patient age and the presence of hydronephrosis into consideration. Complete stone clearance with percutaneous nephrolithotomy was achieved in 21 (67.7%) of 31 patients. Adding extracorporeal lithotripsy increased total clearance to 24/31 (77.4%). The most common complication was bleeding that necessitated blood transfusion (7/31, 22.5%). Conclusion: Percutaneous nephrolithotomy is as safe and effective in children as it is in adults. The clearance rate can be increased with dual therapy. Tract dilation should be tailored according to patient age and the extent of hydronephrosis.

Status quo of percutaneous nephrolithotomy in children

Paediatric nephrolithiasis is quite challenging in terms of management because of the smaller size of the urinary tract and the bigger risk for stone recurrence. Children bear a higher risk of metabolic and infectious causes of stone disease and a longer lifetime risk for recurrence, especially in cases of residual fragments. Complete stone clearance should become the absolute objective and clinically insignificant residual fragments should be avoided. Nowadays, percutaneous nephrolithotomy (PCNL) arises as a logical first-line treatment option for considerable paediatric nephrolithiasis as miniaturization of endoscopes and advances in energy sources for stone fragmentation have facilitated stone-free rates. In this review we present the evolution of PCNL in children and we demonstrate its safety and efficacy. As appropriate instruments are available and relevant surgical experience is accumulating, age should no longer exist as a limiting factor for performing PCNL.

Percutaneous Nephrolithotomy in Children

To review the history of percutaneous nephrolithotomy (PCNL) in children, describe technical considerations, including advancements in equipment, and discuss future directions. A comprehensive literature review was performed using MEDLINE/PubMed to evaluate the use of PCNL in the pediatric population, including historical background, indications, operative techniques, and outcomes. PCNL was first applied to the pediatric population in the 1980s using adult-size instruments. Although there is still concern for potential renal damage in relatively small kidneys, initial investigations have demonstrated its safety and efficacy in children. Operative techniques are similar to those used in adult patients, but considerations specific to pediatric populations must be addressed. Modifications in technique including "mini-perc" access have reduced postoperative morbidity without an appreciable difference in outcomes. Technologic improvements, including miniaturization of endoscopes and advances in energy sources for stone fragmentation, have facilitated stone-free rates comparable to those of adult populations with PCNL monotherapy and sandwich shockwave lithotripsy therapy with minimal postoperative morbidity. Technologic advancements and refinements in technique have facilitated the successful application of PCNL in the pediatric population. As a result, PCNL has now replaced open surgery as the treatment of choice for large stone burdens in children of all ages.

UP-3.151: Percutaneous Nephrolithotomy in Children

UP-3.151: Percutaneous Nephrolithotomy in Children

Extracorporeal Shock Wave Lithotripsy in Prepubertal Children: 22-Year Experience at a Single Institution With a Single Lithotriptor

The sophistication of percutaneous nephrolithotomy and ureteroscopy challenges the efficacy of ESWL for urolithiasis in prepubertal patients. We evaluated our long-term experience with ESWL in these patients and determined its efficiency. We retrospectively reviewed the charts of all prepubertal patients who underwent ESWL. We evaluated the need for tubing, the 3-month stone-free rate, the need for additional ESWL, and the effect of stone size and location, and cystinuria on the 3-month stone-free rate. Between 1986 and 2008, 119 males and 97 females with a mean age of 6.6 years who had urolithiasis underwent ESWL using the Dornier HM3 lithotriptor. We treated 157 children with renal calculi with an average +/- SD diameter of 14.9 +/- 8.9 mm, of whom 66 (42%) required a tube in the urinary system. The 3-month stone-free rate was 80% and 31 patients (19.7%) needed an additional procedure. Stone location did not affect the stone-free rate but stone size did. We treated 59 patients for ureteral stones with an average stone length of 9.5 +/- 4.8 mm, of whom 41 (69%) required tube insertion. The 3-month stone-free rate was 78% and 13 patients (22%) needed an additional procedure. The 3-month stone-free rate did not depend on stone location or size. The rate was 37.5% in patients with cystinuria and 82.5% in all others (p <0.0001). Six patients (2.8%) had complications. The 3-month stone-free rate after ESWL in prepubertal patients is 80% and 20% of patients require additional procedures. ESWL is most effective for kidney stones less than 11 mm. ESWL has inferior results for cystine stones compared to other calculi. Complications are rare.

Tubeless Vs Tubed PCNL in Children

Purpose The Objective of this study is to compare postoperative outcomes between tubeless and conventional large bore nephrostomy tube drainage following percutaneous nephrolithotomy (PCNL) in children. Material and Methods Between May 2005 and February 2006, 54 patients age 14 years and below undergoing percutaneous nephrolithomy (PCNL) in 60 renal units and meeting the inclusion criteria were randomized to placement of a 16F nephrostomy tube (Group A, 30 renal units) or no tube drainage (Group B, 30 renal units) at the end of the procedure. Patient's ages, number and position of stones, operating time, change in haemoglobin, postoperative analgesia requirement, length of hospital stay and post operative complications were compared between the two groups. Inclusion criteria included stone size larger than 1.5 cm, no perforation or tear in palvicalyceal system during procedure, absence of anatomical obstruction e.g. PUJO, single puncture for achieving access tract, no other procedure performed under same anesthesia and no previous surgery on ipsilateral kidney. Results Group A - tubed Group B - tubeless Number of patients 28 (2 simultaneous bilateral) 26 (4 simultaneous bilateral, 1 horse-shoe kidney) Number of renal units 30 30 Male:female 15:13 16:10 Mean age 7.4 years 6.7 years Age range 3-13 years 1-13 years Size of stone (mean) 28.3 mm 21.3 mm Mean change in Hb 0.81mg /dl(0-3.3) 0.63 mg/dl (0-2.1) Mean operating time (minutes) 54.2 66 Ureteric stent in situ 30 29 How long stent retained 1.5 days 1 day Post op abdominal tenderness nil nil Analgesic requirements postoperatively mg of pethidine (mean) 6.8 mg. 4.17mg (p 0.05) Duration of urinary leakage nil Nil Post op US done 0 17 Collection present 0 Nil Post op duration of hospital stay 66 hours 43 hours (p 0.05) Post op complications 5 (UTI 2, Fever 3) 9 (UTI 5, Fever 4) Stone clearance 26 28 Requiring ESWL postoperatively 4 2 Final complete clearance 30 30 Conclusions Tubeless PCNL in children is safe and effective. Post operative analgesia requirement is less and hospital stay is shortened as compared to conventional nephrostomy placement after PCNL.

Percutaneous Nephrolithotomy in Children: Lessons Learned in 5 Years at a Single Institution

We retrospectively compared morbidity and success rates in children who underwent percutaneous nephrolithotomy with 3 different sizes of instruments. Percutaneous nephrolithotomy was performed using adult instruments via a 26Fr tract in 23 patients, using pediatric instruments via a 20Fr tract in 13 and using minimal access (14Fr) in 10. Percutaneous nephrolithotomy was performed using general anesthesia with parenteral antibiotic prophylaxis. Cystoscopy and retrograde pyelography were performed, and 5Fr to 6Fr soft ureteral catheters were placed during each procedure initially. Percutaneous access was established via fluoroscopic guidance with the patient in the prone position. Pneumatic, ultrasonic and holmium laser lithotriptors were used for in situ lithotripsy. A 14Fr nephrostomy catheter was placed at the end of the procedure in the 26Fr and 20Fr groups, and in the minimal access group the ureteral stent was left indwelling in cases of atraumatic procedure with no residual fragments. Mean patient age was 13.2, 5.9 and 6.3 years, respectively, in the 26Fr, 20Fr and minimal access groups (p=0.000). Sex distribution, previous surgery, stone size, surgery and fluoroscopy times, mean hemoglobin decrease and hospitalization time did not differ between the groups. However, blood transfusion rate was higher in groups 1 and 2. Stone-free rates were 69.5%, 80% and 90%, respectively, in groups 1 to 3. Overall, adjuvant shock wave lithotripsy treatment was needed in 3 children. Smaller instrument size to 20Fr did not significantly increase the operative time, and resulted in the same success rates as the adult sized devices. However, low blood transfusion rates were only reached in the minimal access percutaneous nephrolithotomy group.

Post-Percutaneous Nephrolithotomy Extensive Hemorrhage: A Study of Risk Factors

We identified risk factors predicting severe bleeding due to percutaneous nephrolithotomy. Computerized data on 2,909 patients who underwent a total of 3,878 percutaneous nephrolithotomy procedures between January 1995 and December 2005 were retrospectively reviewed. Data on patients who experienced severe bleeding requiring angiographic renal embolization were compared with those on other patients using univariate and multivariate analyses. We tested the characteristics of patients, kidneys and stones together with details of the operative procedure and surgeon experience. Severe bleeding complicated a total of 39 procedures (1%) in 25 males and 14 females with a mean age of 50.7 +/- 12.6 years. Associated morbidity included shock in 6 patients and perirenal hematoma in 4. Renal angiography revealed pseudoaneurysm in 20 patients, arteriovenous fistula in 9, the 2 lesions in 8 and arterial laceration in 2. Bleeding could be controlled with superselective embolization in 36 patients (92.3%). Followup was available on 33 patients (mean 21 +/- 15 months). Renal function was stable in all patients except 3 who had a post-embolization increase in serum creatinine, of whom all had a solitary kidney and none required renal replacement therapy. Significant risk factors for severe bleeding were upper caliceal puncture, solitary kidney, staghorn stone, multiple punctures and inexperienced surgeon. Percutaneous nephrolithotomy should be performed by an experienced endourologist in patients at risk for severe bleeding, such as those with a solitary kidney or staghorn stones.

Tubeless percutaneous nephrolithotomy in children

Objective To assess the effectiveness of tubeless percutaneous nephrolithotomy (PCNL) as an alternative to extracorporeal shock-wave lithotripsy (ESWL) in the management of urolithiasis in children. Materials and methods In 2003–2005 we operated on 20 cases that met the inclusion criteria. Extensive follow-up tests were performed in all patients; stone clearance was defined as the absence of residual fragments on plain abdominal X-ray and renal ultrasound. Pain-scale ruler (0–10) was used to evaluate pain postoperatively. Comparison was made with a group of 10 patients with very similar criteria operated upon with PCN tube. Results Mean follow-up period was 9 months (3–18 months) and mean age 7.5 years (4–15 years). Mean operative time was 115 min (45–180) with no significant bleeding intra- or postoperatively. Conversion to open surgery was necessary in one case. There were no major perioperative complications. In the tubeless group the pain score was 3–6 (mean 4.6), there was no need for IV analgesia, and median hospital stay was 1.7 days (1–4 days); urine leakage occurred in one patient. In the group with PCN tube the pain score was 5–8 (mean 5.5), IV analgesia was mandatory in four patients, and median hospital stay was 2.8 days (3–4 days); urine leakage occurred in five patients and a small residual stone was detected in one child. Conclusion Tubeless PCNL in children has the advantages of being less painful, less troublesome and shortening the hospital stay of the child. The decision to use this procedure is best made intraoperatively and depends on the experience of the surgeon.

Does percutaneous nephrolithotomy in children cause significant renal scarring?

Objective To determine the frequency of renal parenchymal damage following percutaneous nephrolithotomy (PCNL) in children. Patients and methods Fifty-six children undergoing PCNL in 60 renal units between January 2000 and December 2004 were included in this prospective study, and were subjected to postoperative technetium-99m dimercaptosuccinic acid ( 99mTc-DMSA). Using a standard questionnaire, demographics, number, size and location of stones, procedure details, outcome as indicated by clearance with PCNL alone or additional procedures, and follow up were documented. Presence of focal renal damage and its association with the PCNL tract were examined. Results Out of 60 renal units, cortical defects on 99mTc-DMSA scan were seen in 10 renal units (17%). In three of these kidneys, the site of focal defect corresponded to the access site for tract formation during PCNL. Two additional kidneys had scarring at multiple sites, one of which corresponded to the access site during PCNL. In the remaining five kidneys no association between focal renal damage and nephrostomy tract site could be ascertained. No association was seen between renal damage and the size of nephroscope used during PCNL. Conclusion There exists a risk of focal damage to renal parenchyma from the formation of the nephrostomy tract. In our series, focal damage was seen in 5% of patients; this may be an overestimate since preoperative 99mTc-DMSA scans were not available for our patients. Meticulous technique is important combined with a smaller nephroscope to minimize renal damage. Long-term follow up of such children is required to assess how many are left with permanent renal scars.