Pediatric Urolithiasis Research Articles

Pediatric Primary Urolithiasis: 12-Year Experience at a Midwestern Children's Hospital

Due to environmental and social changes (and possibly obesity) as new risk factors for stone formation in adults and changes in imaging techniques, we assessed whether etiologies of primary pediatric urolithiasis have changed, and if relationships exist between the condition and obesity or imaging technique. All pediatric patients with documented primary urolithiasis who underwent serum and 24-hour urine analyses between 1999 and 2010 were evaluated. Age at diagnosis, gender, body mass index and imaging technique were recorded. Of the 222 patients (48% male) all had normal serum creatinine, electrolytes and minerals. Primary pediatric urolithiasis was diagnosed by ultrasound in 73% of cases and computerized tomography in 27%. Mean ± SD annual incidence of urolithiasis per 1,000 clinic visits increased from 2.4 ± 1.5 in the first half of the study period to 6.2 ± 2.1 in the second half (p <0.005). Mean ± SD age at diagnosis was 11.8 ± 3.8 years and body mass index was 21.7 ± 5.7 (rate of overweight 15%). A total of 140 patients had urine output less than 1.0 ml/kg per hour, with this being the only abnormality in 54. Hypercalciuria was observed in 46% of patients, hypocitraturia in 10% and high calcium-to-citrate ratio in 51%. Mild absorptive hyperoxaluria was noted in 3 patients and hyperuricosuria in 11, with all 14 exhibiting at least 1 additional abnormality. Cystinuria was present in 1 patient. No etiology was identified in 20 patients (9.0%). Oliguria and hypercalciuria continue to be the most common etiologies of pediatric primary urolithiasis, followed by hypocitraturia. The recent increase in stone incidence is unlikely due to increased use of computerized tomography. Incidence of obesity was not higher than in the general population. Hyperoxaluria and cystinuria are rare, and thus might not be indicated in the initial analysis.

Assessment of risk factors of pediatric urolithiasis in Egypt.

ObjectivePediatric urolithiasis is a significant medical problem, which has seen an increasing incidence in developing countries. The main objective of the present study was to investigate the clinical characteristics and the most important risk factors that contribute to stone formation in Egyptian children.Patients and methodsThis prospective study was carried out at the outpatient clinics of Cairo university children’s hospital as well as October 6 University hospitals, between November 2008 and March 2012. One hundred and fifty children (100 males, 50 females; mean age 3.5 years; range, 1-14 years) suffering from urinary stones were included. The mean follow-up duration; 33.1 months. All patients underwent detailed medical and family histories, dietary habits and physical examination, including Growth percentiles. Laboratory investigations were performed including: complete urine analysis and culture and sensitivity tests, urine collection in 24-h to quantity urinary volume, pH, calcium, uric acid, magnesium, creatinine, oxalate and citrate. Blood samples were obtained to measure (serum creatinine, calcium, phosphorus, uric acid level, and alkaline phosphatase and electrolyte levels, in addition to pH and pCO2 values). Radio-sonographic investigation of the abdomen and pelvis was also performed.ResultsThe commonest presentations were abdominal pain in 42 children (28%) and gross hematuria in 35 patients (23%). Urinary tract infection was the most common risk factor, 60 patients (40%) had UTI, 70% of them had recurrent infections. Genito-urinary abnormalities, as a risk factor, were detected in 38 children (25%), with vesico-uretheral refux being the commonest abnormality (18/38). Metabolic risk factors were detected in 34 children (23%) with hypercalciuria and hyperoxaluria being the commonest metabolic abnormalities. Treatments used were, ESWL in 69 patients (46%), endoscopic interventions in 40 children (27%) and open surgery in 15 children (10%). The remaining 26 children (17%) were managed conservatively.Conclusionstreatment of pediatric urolithiasis requires stone removal besides a thorough metabolic and environmental evaluation of all patients on an individual basis, entailing the treatment of metabolic abnormalities. Children with a positive family history should be followed up cautiously to avoid stone recurrence.

Predictive Factors and Management of Steinstrasse After Shock Wave Lithotripsy in Pediatric Urolithiasis—A Multivariate Analysis Study

To define the predictive factors for the formation of steinstrasse (SS) after shock wave lithotripsy (SWL) and determine the treatment strategies for this complication in pediatric urolithiasis. We retrospectively reviewed the data of 341 renal units (RUs) treated with SWL for urolithiasis. The stone location, stone burden, auxiliary procedures, energy level, and number of shock waves were recorded. Statistical analysis was performed to detect the predictive factors for the formation of SS. In addition, the treatment of children with SS was evaluated. The mean age of the children was 8.31 years (range 1-17). Episodes of SS developed in 26 RUs (7.6%). Of the 26 RUs, 20 (77%) were localized in the lower, 5 (19%) in the upper, and 1 (4%) in multiple locations in the ureter. The stone burden was the only statistically significant factor predicting the formation of SS on logistic regression analysis (P = .001). Of the 26 RUs, 17 (65.4%) were successfully managed by repeat SWL monotherapy, 4 (15.4%) were managed with ureteroscopy after failure of SWL, 1 (3.8%) was managed by ureteroscopy monotherapy, and 4 (15.4%) were monitored with conservative management with antispasmodic drug plus hydration therapy. The mean number of SWL sessions was 1.72. The incidence of SS development in children after SWL treatment was similar to that in adult series. Our results suggest that the stone burden is a significant predictive factor for the development of SS after SWL in pediatric urolithiasis. Most children with SS could be easily and safely treated by repeat SWL.

From Hypercalciuria to Hypocitraturia—A Shifting Trend in Pediatric Urolithiasis?

We analyzed the metabolic abnormalities in children with urolithiasis, and the relationship between diet and hypocitraturia. A single center, retrospective analysis was conducted in all children with renal and/or ureteral calculi seen at our Multidisciplinary Stone Clinic between January 2010 and July 2011. Data at presentation were extracted from the clinical database. We analyzed 63 children (37 girls) with urolithiasis with a mean age of 13.43 ± 4.61 years. Of the 45 patients with 24-hour urinalysis, a metabolic risk factor was present in 68.9%, with hypocitraturia (58.1%) and hypercalciuria (48.3%) being the most common. Children with isolated hypocitraturia had lower urinary magnesium and potassium levels (1.06 ± 0.62 mg/kg and 0.53 ± 0.24 mmol/kg per day) than those with no metabolic abnormalities (1.72 ± 0.61 mg/kg and 0.68 ± 0.20 mmol/kg per day) (p = 0.015 and p = 0.132, respectively). Urinary citrate was positively correlated with urinary potassium (r = 0.50, p = 0.002) and urinary magnesium (r = 0.49, p = 0.001). Dietary analysis revealed a lower intake of magnesium and potassium in children with hypocitraturia (28.97% ± 12.25% and 15.42% ± 7.25% recommended dietary index) than in normocitraturic cases (51.06% ± 17.51% and 45.23% ± 29.49% recommended dietary index) (p = 0.042 and p = 0.056, respectively). The majority of children had an identifiable metabolic risk factor for urolithiasis, with hypocitraturia being the most common. This shift in metabolic trend may be a significant contributor to the increasing incidence in pediatric urolithiasis. Hypocitraturia appears to be dietary in origin, correlated with a low consumption of potassium and magnesium.

Association of Urolithiasis with Systemic Conditions Among Pediatric Patients at Children's Hospitals

Urolithiasis is associated with systemic medical conditions in adults but associations have not been well studied in children. We investigated the association of urolithiasis with diabetes mellitus, hypertension and obesity among children with and without urolithiasis. We performed a matched case-control study using the PHIS (Pediatric Health Information System) database. ICD-9 codes identified urolithiasis cases from 2004 to 2009. Four randomly selected controls were matched by age, hospital, patient care setting and year of treatment. Diagnoses from all hospital encounters were ascertained for comorbid conditions. Univariate and multivariable conditional logistic regression was used to assess the associations of urolithiasis with diabetes mellitus, hypertension and obesity. We identified 9,843 urolithiasis cases and 39,047 controls. On univariate analysis stone formers had significantly higher odds of obesity (OR 1.44, 95% CI 1.27-1.64) and hypertension (OR 2.12, 95% CI 1.88-2.40) compared to controls. The odds of type I diabetes mellitus was lower among cases compared to controls (OR 0.38, 95% CI 0.30-0.48). After adjusting for gender, race, insurance type and number of visits using logistic regression, children with urolithiasis still had higher odds of obesity (AOR 1.30, 95% CI 1.12-1.51) and hypertension (AOR 1.61, 95% CI 1.40-1.86) as well as lower odds of type I diabetes mellitus (AOR 0.32, 95% CI 0.25-0.41) compared to controls. Among pediatric patients at freestanding children's hospitals, urolithiasis is associated with higher odds of obesity and hypertension and lower odds of type I diabetes mellitus. These findings may be helpful in further elucidating the etiology of pediatric urolithiasis.

Minimally Invasive Surgical Approaches to Kidney Stones in Children

The existing treatment options for pediatric urolithiasis are endoscopic methods. Extracorporeal shockwave lithotripsy (SWL) is the first-line option for most of the kidney stones smaller than 1 cm in diameter. For larger stones or refractory cases, minimally invasive surgical methods are preferred. Percutaneous nephrolithotomy (PCNL) is a well-established treatment modality for most patients. This technique has shown evolution also in children so that miniaturized or tubeless methods could now be performed. Recent series show that flexible ureteroscopy is also becoming an important treatment option in the pediatric urology armamentarium for treating the calyceal and lower pole stones. Open surgery has a very limited role and it may be of use when there is a need to do an adjuvant reconstructive surgery. With the increasing experience, laparoscopic surgery is becoming an alternative option that may have potential to replace the open techniques.

Pediatric percutaneous nephrolithotomy using adult sized instruments: our experience.

To evaluate the safety and efficacy of pediatric percutaneous nephrolithotomy (PCNL) using adult sized instruments in the management of pediatric urolithiasis. We retrospectively reviewed the medical records of 38 children younger than 15 years who had undergone 45 PCNLs with adult sized instruments in our center between August 2007 and February 2010. There were 26 boys and 12 girls, with a mean age of 8.4 ± 4.24 years (range, 12 months to 13 years). Twelve patients had complete staghorn stone. Mean stone burden was 2.93 ± 0.89 cm. The tract was dilated between 26 and 30F. Standard PCNL was performed in 8 patients and tubeless PCNL in the next 37 subjects. Simultaneous transurethral lithotripsy was done in 9 patients. Stone clearance rate was 67%. Mean pre and postoperative hemoglobin levels were 12.67 ± 1.7 and 11.39 ± 1.6 g/dL, respectively. Mean hospitalization was 3.5 ± 1.1 days. Eight subjects had postoperative fever beyond day 1. Blood transfusion was required in only one patient. In one patient (3 years old) with a staghorn stone, hyponatremia and seizure occurred, which were treated conservatively without any adverse sequela. There was a significant difference in hospital stay between tubeless and standard PCNL groups (P < .02). We concluded that PCNL using adult sized instruments was relatively safe in children, with a clearance rate of 67%. We suggest prospective randomized studies to compare mini-perc and adult sized instruments use in pediatric PCNL.

Safety and efficacy of percutaneous nephrolithotomy for the treatment of paediatric urolithiasis.

INTRODUCTIONPaediatric percutaneous nephrolithotomy (PCNL) has revolutionised the treatment of paediatric nephrolithiasis. Paediatric PCNL has been performed using both adult and paediatric instruments. Stone clearance rates and complications vary according to the technique used and surgeon experience. We present our experience with PCNL using adult instruments and a 28Fr access tract for large renal calculi in children under 18 years.METHODSAll patients undergoing PCNL at our institution between 2000 and 2009 were reviewed. Demographics, surgical details and post-operative follow-up information were obtained to identify stone clearance rates and complications.RESULTSPCNL was performed in 32 renal units in 31 patients (mean age: 10.8 years). The mean stone diameter was 19mm (range: 5–40mm). Twenty-six cases required single puncture and six required multiple tracts. Overall, 11 staghorn stones, 10 multiple calyceal stones and 11 single stones were treated. Twenty-seven patients (84%) were completely stone free following initial PCNL. Two cases had extracorporeal shock wave lithotripsy for residual fragments, giving an overall stone free rate of 91% following treatment. There was no significant bleeding or sepsis encountered either during the operation or in the post-operative setting. No patient required or received a blood transfusion.CONCLUSIONSPaediatric PCNL can be performed safely with minimal morbidity using adult instruments for large stone burden, enabling rapid and complete stone clearance.

Current management of paediatric urolithiasis

We aimed to review a current management of paediatric nephrolithiasis. The current literature, including our own experience on the treatment of paediatric nephrolithiasis was reviewed by MEDLINE/PubMed search. We have used in our search following keywords: urolithiasis, nephrolithiasis, paediatrics, surgical treatment, conservative management, ESWL, ureteroscopy, and open renal surgery. The search was limited to the English language literature during the period of time from 1990 to 2011. All papers were reviewed independently by all co-authors and only the manuscripts directly related to the reviewed subjects were included into the current review. Due to the high incidence of predisposing factors for urolithiasis in children and high stone recurrence rates, every child with urinary stone should be given a complete metabolic evaluation. Most stones in children can be managed by ESWL and endoscopic techniques. Paediatric stone disease is an important clinical problem in paediatric urology practice. Because of its recurrent nature, every effort should be made to discover the underlying metabolic abnormality so that it can be treated appropriately. Obtaining a stone-free state with interventional management and close follow-up are of utmost importance.

Laparoscopic management of pediatric renal and ureteric stones

ObjectiveTo assess the feasibility of laparoscopy in the treatment of pediatric urolithiasis, we report our experience with the transperitoneal laparoscopic removal of stones. MethodRenal pelvic stones of size ≥1 cm on ultrasound were included for laparoscopic pyelolithotomy while smaller stones were managed with shock-wave lithotripsy monotherapy. Intrarenal stones, calyceal stones, complete staghorn stones, multiple stones and kidneys with intrarenal pelvis were excluded. Ureteric stones included for laparoscopic ureterolithotomy were of size ≥1 cm in the upper, mid or lower ureter, and smaller stones not responding to non-operative treatment. ResultsA total of 22 procedures were performed: 12 pyelolithotomies, and 8 lower and 2 upper ureterolithotomies. Complete removal of calculi was accomplished in 21 (95.45%) procedures. Complications associated with laparoscopic lithotomy included urinoma (4.54%), failure (4.54%) and omental prolapse (4.54%). ConclusionLaparoscopic lithotomy is safe and feasible in pediatric urolithiasis with pyelic and ureteric stones, with minimal complications and failure rate.

833 IS BMI ASSOCIATED WITH STONE FORMATION IN CHILDREN? SINGLE CENTER, PROSPECTIVE ANALYSIS

INTRODUCTION AND OBJECTIVES: Multiple reports exist identifying an increasing epidemic of pediatric urolithiasis in the modern era. Causative factors have been postulated, such as the obesity and fast food epidemics. We hypothesize that BMI is not truly causative, but more likely a confounding factor, in pediatric stone formers. METHODS: A two-year prospective clinical trial enrolled 52 patients through the Pediatric Urology department at the Childreni s Hospital of Pittsburgh. Patient demographics, BMI, method of stone diagnosis, stone analysis, 24 hour urine studies, labs and spot urine studies, and treatments were catalogued. Logistic regression analysis was used to compare variables among stone forming children iU age 18. RESULTS: Data on BMI was available for 49 of 52 stone forming children. Imaging data was available in 46 of 49 patients, including confirmation by CT in 40 (87%), ultrasound in 3 (6.5%), and KUB in 3 (6.5%). The median age of presenting children was 15 (mean: 14.4 2.5), median stone burden 2.8mm (mean: 3.5 1.7) and median BMI 20.0 (mean: 20.4 4.2). Approximately 10% (5/49) children were overweight (BMI 25-30) and only 2% (1/49) were obese. Infected stones were present in 2 children (4.3%), and end stage renal failure in 1 (2.2%). Litholink® studies were completed on all 49 patients; 24hr urine electrolytes are as outlined in Table 1. No patients had cystinuria. CONCLUSIONS: mong pediatric stone formers, we did not find higher rates of obesity than compared with the local population. In fact, all overweight children forming stones in our cohort accounted for only 10% of total patients. Both normal and overweight children had low citrate levels by Litholink assay, although overweight children had a more substantial reduction in urinary citrate. Greater patient numbers are needed to determine the true effect of obesity on 24 hour urine parameters, and the reversible causes for increased stone formation, including dietary analysis.

Pediatric Urolithiasis in Taiwan: A Nationwide Study, 1997-2006

To investigate the prevalence, incidence, associated risk factors, and treatment of pediatric urolithiasis in Taiwan. The present study used a subset of the National Health Insurance Research Database, known as the Longitudinal Health Insurance Database 2005, which contains the data for all paid medical benefit claims from 1997 to 2006 for a subset of 1 million beneficiaries randomly drawn from the population of 22.72 million individuals during any part of the calendar year 2005. Our analysis included the data of all newly diagnosed pediatric patients with an "International Classification of Disease, 9th revision," diagnosis of urolithiasis from 1997 through 2006. A total of 1679 pediatric subjects who had newly diagnosed urolithiasis without a previous attack were identified from 1997 to 2006 as the study sample. Of the 1679 patients, 808 were boys (48.1%) and 871 were girls (51.9%). The incidence rate of urolithiasis in 2005 was 0.047%. The peak age of pediatric stone occurrence in the study sample was 15-18 years (49.6%). The most common associated disease was urinary tract infection (34.1% of all subjects). The occurrence rate of pediatric urolithiasis correlated significantly with the urbanization level of the residence and geographic area. Using a nationwide, population-based study provides important clinical and epidemiologic information regarding pediatric urolithiasis. Additional studies are warranted to determine the effect of geographic area and urbanization level on the occurrence of pediatric stone disease.

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.

Extracorporeal shock wave lithotripsy as first line treatment for urinary tract stones in children: outcome of 500 cases

The continued evolution of stone treatment modalities, such as endourologic procedures, open surgery and shock wave lithotripsy, makes the assessment of continuous outcomes are essential. Pediatric urolithiasis are an important health problem allover the world, especially in Middle East region. We evaluate the safety, efficacy and factors affecting success rate and clearance of stones in children treated with shock wave lithotripsy. Between 2005 and 2010, a total of 500 children with stones in the upper urinary tract at different locations were treated by Extracorporeal shock wave lithotripsy (ESWL) in our department, Sohag University, Egypt. We have used the Siemn's Lithostar Modularis machine, Germany. A total of 371 boys and 129 girls with the average age of 8.63 ± 5 years, and a range from 9 months to 17 years were included in this study. Diagnosis of their urinary calculi was established either by the use of abdominal ultrasound, plain X-ray, intravenous urography, or CT scan. The stones were located in the kidney in 450 (90%) patients; 298 (66%) pelvic, 26 (5.7%) upper calices, 57 (12.6%) mid calices, and lower calices in 69 (15.3%) patients. The average of their stone sizes was 12.5 ± 7.2 mm. The other 50 children their stone were located in the proximal ureteral stones in 35 patients (70%); middle third in 5 (10%) patients and in the distal ureter in 10 (20%) patients. The average ureteral stone size was 7.5 ± 3.2 mm. All children were treated under general anesthesia with adequate lung and testes shielding using air foam. We treated the distal ureteral stones of young children in the supine position through greater sciatic foramen and lesser sciatic foramen as the path of shockwave instead of prone position, which is not a comfortable or natural position and could adversely affect cardiopulmonary function especially under general anesthesia. Localization was mainly done by ultrasound, and X-ray was only used to localize ureteral calculi. For follow-up, we have used abdominal ultrasound, plain X-ray, and CT scan if needed to confirm stone disintegration and clearance. The overall success rate for renal and ureteral calculi was 83.4 and 58.46%, respectively. The re-treatment rate was 4% in renal group and 28% for the ureteral group. No serious complications were recorded in our patients. Minor complications occurred in 15% of our patients; renal colic was reported in 10% of our treated patients, and repeated vomiting was reported in 5% that respond to antiemetics. In the renal group; children with history of pervious urologic surgical procedures had low success rate of stone clearance after ESWL. In the ureteral group stone burden, stone location, had a significant impact on stone clearance outcome. This study showed that SWL in pediatric age group for both renal and ureteral stone is cost effective, safe with an acceptable re-treatment rate; however children with large stone burden or previous urologic surgery have low success rate.

Pediatric urolithiasis: causative factors, diagnosis and medical management

Childhood urolithiasis is associated with considerable morbidity and recurrence. Many risk factors--including those metabolic, genetic, anatomic, dietary and environmental in nature--have been identified in children with urinary tract calculi. As pediatric urolithiasis with a metabolic etiology is the most common disease, evaluating the metabolic risk factors in patients is necessary to both effectively treat current stones and prevent recurrence. We discuss causative risk factors of pediatric urolithiasis, as well as the diagnostic and therapeutic approaches.

PEDIATRIC UROLOGY Large stone clearance in 2-year-old child with staghorn and calyceal stones using SWL monotherapy

Treatment of pediatric urolithiasis requires a thorough metabolic and urological evaluation on an individual basis.The objective of our case report was to determine the efficiency and the role of shockwave lithotripsy (SWL) in the treatment of pediatric urolithiasis.In this case report we reported our own experience in the management of staghorn and calyceal stones in both kidneys with SWL.In our case, clearance of multiple staghorn stones and a calyceal stone was obtained without any complications after 7 sessions of SWL over 2 months.

Treatment of pediatric urolithiasis: how small is “small enough”?

“Big” scars for stone removal are only needed in unusual circumstances. This is true given the fact that technology is fast evolving and instruments becoming smaller and smaller. The management of urolithiasis in children has undergone a paradigm shift in the past decade. Management of pediatric urolithiasis necessitates a balance between stone clearance and morbidity related to the procedure. A variety of treatment options are available, which include shock wave lithotripsy (SWL), percutaneous Nephrolithotomy (PCNL), and retrograde intra renal surgery (RIRS) and open surgery. Concerns regarding endourologic treatment include eVect on the renal development and function, the side eVects of radiation, and the implications of residual stones. Children with pediatric urolithiasis need to be worked up metabolically to prevent recurrence. The treatment options should be chosen with prudence, as each of the treatment options has its share of problems. SWL has been the treatment of choice for renal calculi less than 15 mm in size. The stone-free rates range from 68 to 84% [1]. In our study, ESWL was found to be safe and eVective in children as was in adults for solitary renal and upper ureteric stones less than 2 cm in size. We found that children required fewer and lower energy shock waves to achieve equivalent results. Considering that long-term data are awaited regarding functional consequences of shock waves on pediatric kidneys, it would be prudent to shock these kidneys as little as possible. In this context, we feel to minimize the “shock loss,” and optimizing the number and energy of shock waves, the patient should be given optimum anaesthesia with the use of ultrasound and Xuoroscopy for localizing and monitoring of stone fragmentation [2]. PCNL remains the most eVective option for treating large stones in this age group. The obvious downside of this approach is the potential for life-threatening complications such as bleeding; hence, surgeon experience is paramount in deciding the number and site of access. Stone-free rates of more than 90% have been shown in pediatric age group [3]. Percutaneous Nephrolithotomy has been described even in children as small as 11 months, having complex calyceal stones and/or staghorn calculi. The method to gain access, ultrasound or Xuoroscopy, is a matter of experience and personal preference. Ultrasound oVers the advantage of visualization of spleen and liver and avoids injury. It also minimizes radiation to these kids. The key to success in PCNL in these small patients is staging the procedure if required, miniaturization of instruments, and using ultrasound as the method of achieving access. PCNL oVers a good clearance rates with acceptable morbidity. Miniaturization of instruments particularly smaller nephroscopes and newer energy sources will decrease the morbidity of PCNL. The question is how small is small enough! In this regard, in our opinion, microperc is the “new kid on the block.” It has a role to play in percutaneous management of these small patients. Essentially, “microperc” involves performing the procedure through the eye of the needle. The microoptics of 0.9 mm diameter are used. The assembly has a integrated light head inserted through the working sheath of the needle, and PCNL can be done through the same needle sheath with a 3-way needle allowing irrigation, passage of Xexible telescope and a laser Wbre [4]. Although investigational, larger multicentre trials that are already underway will prove its utility. M. Desai (&) Nadiad, India e-mail: mrdesai@mpuh.org

Approach to Stone Formation in the Pediatric Population

Pediatric urolithiasis is more common than previously reported. All children with urolithiasis deserve a thorough evaluation after their initial presentation. With careful assessment, metabolic risk factors may be found in the majority of children, leading to appropriate medical therapy of modifiable risk factors and prevention of further stone formation. Furthermore, early identification of inborn errors of metabolism is important to prevent morbidities associated with these disorders, such as end-stage renal disease. This review discusses the etiologies of pediatric urolithiasis, the metabolic evaluation, and treatment options.

Management of Pediatric Urolithiasis Induced by Melamine-contaminated Powdered Formula (Report of 619 Cases)

To investigate the clinical features and therapeutic efficacy in children with urolithiasis caused by ingestion of melamine-contaminated powdered formula. The clinical presentation, laboratory data, ultrasound findings, and treatment methods used for 619 children with melamine-induced urolithiasis were retrospectively recorded and analyzed. The efficacy of the treatment in these children was summarized and evaluated. A total of 619 children aged 1-88 months were included in the present study (mean age 16.32 months). The male/female ratio was 1.9:1. Of the 619 patients, 577 received conservative treatment and 454 became stone free (78.7%). Of the 151 patients with renal and/or ureteral stones, 1-6 sessions of extracorporeal shock wave lithotripsy were performed in 81 patients (61 successful [35.5%] of 172 sessions) and retrograde ureteral catheterization in 70 patients (56 successfully treated [80.0%]). In centers without expertise in minimally invasive medical techniques, 5 patients with bilateral obstructive renal failure were successfully treated with ureteral lithectomy (n = 4) and percutaneous nephrostomy (n = 1). For the remaining 27 children with refractory renal or ureter stones, 9 were successfully treated with percutaneous nephrolithotomy and 18 children underwent ureteroscopic lithotripsy to become stone free. A total of 22 bladder and/or urethral stones were successfully treated with cystoscopic lithotripsy. Most children with melamine-induced urolithiasis were treated successfully with an infusion of fluids, urine basification, and diuresis. Extracorporeal shock wave lithotripsy is a safe and effective technique for patients in whom conservative treatment fails. However, for patients who have presented with obstructive renal failure, surgical intervention should be considered as early as possible to relieve the obstruction.

Safety of shock wave lithotripsy for treatment of pediatric urolithiasis: 20-year experience

Safety of shock wave lithotripsy for treatment of pediatric urolithiasis: 20-year experience