Long-term results of extracorporeal shock wave lithotripsy in children

Acoustic shadowing in pediatric kidney stone ultrasound: a retrospective study with non-enhanced computed tomography as reference standard

BACKGROUND

The usefulness of acoustic shadowing as a feature of pediatric kidney stone ultrasound (US) may be underestimated.

OBJECTIVE

The hypothesis was that the majority of stones in children have acoustic shadowing and that its specificity is high (>90%) in pediatric kidney stones.

MATERIALS AND METHODS

Our retrospective observational study included children who had undergone abdominal non-enhanced computed tomography (CT) for kidney stones in a pediatric renal stone referral centre between 2015 and 2016. US examinations prior to CT were retrospectively assessed for US features such as acoustic shadowing, twinkle artifact and stone size. These features were compared to CT as reference standard.

RESULTS

Thirty-one patients (median age: 13 years, range: 1-17 years) with 77 suspected kidney stones were included. The median stone size was 5 mm (interquartile range [IQR]: 5 mm). For acoustic shadowing, sensitivity was 70% (95% confidence interval [CI] 56-80%) and specificity was 100% (95% CI 56-100%). All kidney stones with a diameter ≥9 mm demonstrated shadowing. Sensitivity for twinkle artifact was 88% (95% CI 72-96%), but specificity for twinkle artifact could not be calculated due to the lack of true negatives. All false-positive stones on US demonstrated twinkle artifact, but none showed shadowing.

CONCLUSION

Acoustic shadowing was demonstrated in the majority of pediatric kidney stones. Specificity was high, but this was not significant. Twinkle artifact is a sensitive US tool for detecting (pediatric) kidney calculi, but with a risk of false-positive findings.

Complications of surgical management of upper tract calculi in spina bifida patients: analysis of nationwide data

PURPOSE

The management of upper urinary tract stones in patients with spina bifida is challenging but poorly described in the literature. We compared urolithiasis interventions and related complications in patients with spina bifida to those in other stone formers using a national database.

MATERIALS AND METHODS

We retrospectively reviewed the NIS to identify hospital admissions for renal and ureteral stones from 1998 to 2011. We used ICD-9-CM codes to identify urological interventions, including shock wave lithotripsy, ureteroscopy, percutaneous nephrolithotomy and ureteral stent placement. NSQIP data were used to identify postoperative complications.

RESULTS

We identified 4,287,529 weighted stone hospital admissions, including 12,315 (0.3%) of patients with spina bifida. Compared to those without spina bifida the patients with spina bifida who had urolithiasis were significantly younger (mean age 34 vs 53 years), more likely to have public insurance (72% vs 44%) and renal vs ureteral calculi (81% vs 58%), and undergo percutaneous nephrolithotomy (27% vs 8%). After adjusting for age, insurance, comorbidity, treatment year, surgery type, stone location and hospital factors patients with spina bifida were more likely to have urinary tract infections (OR 2.5), urinary complications (OR 3.1), acute renal failure (OR 1.9), respiratory complications (OR 2.0), pneumonia (OR 1.5), respiratory insufficiency (OR 3.2), prolonged mechanical ventilation (OR 3.2), sepsis (OR 2.7), pulmonary embolism (OR 3.0), cardiac complications (OR 2.4) and bleeding (OR 1.6).

CONCLUSIONS

Compared to those without spina bifida the patients with spina bifida who were hospitalized for urolithiasis were younger, and more likely to have renal stones and undergo percutaneous nephrolithotomy. Urolithiasis procedures in patients with spina bifida were associated with a significantly higher risk of in-hospital postoperative complications.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Factors affecting complication rates of percutaneous nephrolithotomy in children: results of a multi-institutional retrospective analysis by the Turkish pediatric urology society

PURPOSE

We assessed factors affecting complication rates of percutaneous nephrolithotomy in children.

MATERIALS AND METHODS

We retrospectively evaluated data on 1,205 renal units in 1,157 children treated with percutaneous nephrolithotomy at 16 Turkish centers between 1991 and 2012. Of the patients 28.3% had a history of urolithiasis. Complications were evaluated according to the Satava classification system and modified Clavien grading system. Univariate and multivariate analyses were done to determine predictive factors affecting complication rates.

RESULTS

A total of 515 females and 642 males were studied. Mean ± SD patient age was 8.8 ± 4.7 years (range 4 months to 17 years). Mean ± SD stone size, operative time and postoperative hospital stay were 4.09 ± 4.06 cm(2), 93.5 ± 48.6 minutes and 5.1 ± 3.3 days, respectively. Postoperative stone-free rate was 81.6%. A total of 359 complications occurred in 334 renal units (27.7%). Complications were intraoperative in 118 cases and postoperative in 241. While univariate analysis revealed that stone history, positive urine culture, operative time, length of hospitalization, treatment success, punctured calyx and location of the stone significantly affected the complication rates (p <0.05), operative time, sheath size, mid calyceal puncture and partial staghorn formation were the statistically significant parameters affecting complication rates on multivariate logistic regression analysis.

CONCLUSIONS

Percutaneous nephrolithotomy is the treatment of choice for most renal calculi in children. The technique is effective and safe in children, with a high success rate and a low rate of major complications. The significant factors identified should be considered by clinicians to decrease associated complication rates.

The management of staghorn calculi in children

OBJECTIVES

To review reports focusing on the surgical treatment of staghorn stones in children, as despite all the improvements in the surgical treatment of paediatric urolithiasis the management of staghorn calculi still represents a challenging problem in urology practice.

METHODS

To evaluate current knowledge about treating staghorn calculi in children, we searched PubMed for relevant articles published between 1991 and 2011, using a combination of related keywords, i.e. staghorn stone, child, kidney calculi, surgical treatment, electrohydraulic shockwave therapy (ESWL), percutaneous nephrolithotomy (PCNL), and open surgery. Reports relating to the treatment of paediatric stone disease in general (open surgery, PCNL, ESWL) were also searched with the same method. Additional references were obtained from the reference list of full-text reports.

RESULTS

Although open surgery had been widely used in the past for treating such stones in children, currently it has only limited indications in highly selected patients. Current published data clearly indicate that, in experienced hands, both PCNL and ESWL are now effective methods for treating staghorn calculi in children.

CONCLUSIONS

Due to advanced techniques and instrumentation, it is now possible to successfully treat staghorn calculi in children, with very limited safety concerns. Currently, while PCNL is recommended as the first-line surgical treatment, ESWL, open surgery and/or combined methods are valuable but secondary options in the treatment of paediatric staghorn calculi.

Treatment of Kidney Stones Using Extracorporeal Shock Wave Lithotripsy (ESWL) and Double-J Stent in Infants

Background. Extracorporeal shock wave lithotripsy (ESWL) has progressively acquired popularity as being the gold standard treatment for upper urinary tract lithiasis in infants since 1980. Our aim was to evaluate the outcome of ESWL for kidney stones and the use of double-J stent in infants. Material and Methods. A prospective clinical trial study performed on 50 infants with renal calculi at pelvic admitted in the Urology ward of Shafa Hospital, Sari, Iran, between 2001 and 2010. Main outcome measure of our study was clearing stones after one or more consecutive sessions of ESWL. Results. The study included 50 patients with renal calculi at pelvic. Among them, there were 35 (70%) boys and 15 (30%) girls with the age ranging from 1 to 13 months (mean of 7 month ± 3 days). All of them were treated by standard ESWL using Simons Lithostor plus machine. The stone sizes ranged from 6 mm to 22 mm. Double-J stents were placed in 11 infants (22%) with stones larger than 13 mm. Most of the patients required only one ESWL session. Conclusion. Since there were no complications following ESWL treatment, we can conclude that, in short term, ESWL is an effective and safe treatment modality for renal lithiasis in infants. In addition, we recommend double-J stent in infants with stones larger than 13 mm.

Surgical management of pediatric urolithiasis

Pediatric urolithiasis poses a technical challenge to the urologist. A review of the recent literature on the subject was performed to highlight the various treatment modalities in the management of pediatric stones. A Medline search was used to identify manuscripts dealing with management options such as percutaneous nephrolithotomy, shock wave lithotripsy, ureteroscopy and cystolithotripsy in pediatric stone diseases. We also share our experience on the subject.

Shock wave lithotripsy should be the treatment modality for renal stone less than 1cm or < 150 mm² and proximal non-impacted ureteric stone less than 1 cm with normal renal function, no infection and favorable anatomy. Indications for PCNL in children are large burden stone more than 2cm or more than 150mm² with or without hydronephrosis, urosepsis and renal insufficiency, more than 1cm impacted upper ureteric stone, failure of SWL and significant volume of residual stones after open surgery. Shock wave lithotripsy can be offered for more soft (< 900 HU on CT scan) renal stones between 1-2cm. Primary vesical stone more than 1cm can be tackled with percutaneous cystolithomy or open cystolithotomy. Open renal stone surgery can be done for renal stones with associated structural abnormalities, large burden infective and staghorn stones, large impacted proximal ureteric stone. The role of laparoscopic surgery for stone disease in children still needs to be explored.

Pediatric urolithiasis: the current surgical management

Children represent about 1% of all patients with urolithiasis, but 100% of these children are considered high risk for recurrent stone formation, and it is crucial for them to receive a therapy that will render them stone free. In addition, a metabolic workup is necessary to ensure a tailored metaphylaxis to prevent or delay recurrence. The appropriate therapy depends on localization, size, and composition of the calculus, as well as on the anatomy of the urinary tract. In specialized centers, the whole range of extracorporeal shock-wave lithotripsy (ESWL), ureterorenoscopy (URS), and percutaneous nephrolithotomy (PCNL) are available for children, with the same efficiency and safety as in adults.

Safety of ungated shockwave lithotripsy in pediatric patients

OBJECTIVE

Ungated extracorporeal shockwave lithotripsy (ESWL) in adults is associated with cardiac arrhythmias. We report on the safety and efficacy of this method for treatment of renal calculi in children.

PATIENTS AND METHODS

Children under 14 years with radio-opaque renal stones were treated by ungated ESWL. Pre-treatment plain radiographs and intravenous urography and post-treatment ultrasonography and plain films were used to follow up clearance of fragments. All children were monitored for arrhythmias.

RESULTS

Thirty-seven children (28 males, nine females) with a median age of 5 years (range 2-14 years) underwent 69 ungated ESWL sessions for renal calculi. Nineteen children had stones located in the left kidney, 17 had stones located in the right kidney and one child had bilateral renal stones. The stone size ranged from 6 to 25 mm (mean 9.9 mm). Shockwave number ranged from 800 to 3650 (mean of 2500 shockwaves per session). All children underwent lithotripsy with a gradual incremental energy increase from 14 to 20 kV. No patient had cardiac arrhythmias or other intra-procedural complications. No patient required conversion to gated ESWL. The overall stone-free rate was 86%.

CONCLUSION

The results suggest that ungated ESWL is safe in children under 14 years. The efficacy was comparable to that of gated ESWL from previously published series.

Is extracorporeal shock wave lithotripsy in pediatrics a safe procedure?

Removal of urinary calculi is an essential element in the successful treatment of patients with urinary stone disease. The new generation of lithotriptors allows the treatment without the need for general anesthesia. The patients, often outpatients, have a faster discharge from the hospital with a reduction of hospitalization time and operating costs. Shock wave lithotripsy (SWL) is currently considered a safe technique for treatment of pediatric urinary lithiasias, with a low percentage of complications and subsequent surgical retreatments. But can we define SWL as a safe procedure in pediatrics? Herein, we will review the literature to justify SWL safety in children, focusing on important parameters as the insertion of preoperative stenting, side effects, and complications after the procedure.

Pediatric shockwave lithotripsy: size matters!

BACKGROUND AND PURPOSE

Shockwave lithotripsy (SWL) is a safe and efficacious modality for pediatric urolithiasis. Recent reports claim good results even with larger stone burdens, irrespective of stone location. We reviewed the outcomes of SWL in the pediatric population at our center to assess the impact of stone burden and location and the age of the child on the stone-free rate.

PATIENTS AND METHODS

Records of 106 patients <or=16 years of age (mean age 10.9 years) treated with SWL for stones with a surface area of 20 to 600 mm2 (mean 124.17 mm2) from July 1989 to June 2004 were reviewed. Metabolic abnormalities were present in 20.7% of the patients. All procedures were performed using the Siemens Lithostar, and stone clearance was assessed 3 months after SWL. Complications and the need for re-treatment and ancillary procedures were noted, and the impacts of stone size and location and the age of the child on stone clearance were assessed.

RESULTS

The overall stone-free rate was 87% (complete clearance 72%; insignificant [<3-mm] residual fragments 15%). The re-treatment rate was 58%, and the efficiency quotient was 47. Whereas stone size correlated strongly with the stone-free rate (Mann-Whitney U test x = 0.004; chi-square test P = 0.02), patient age and stone location did not have a significant impact.

CONCLUSIONS

Extracorporeal shockwave lithotripsy is an effective modality to treat pediatric upper urinary-tract calculi, especially when the stone burden is <200 mm2. Larger stone burdens are associated with poorer results, necessitate more ancillary procedures, and have a higher complication rate.

Endourologic management of pediatric urolithiasis: proposed clinical guidelines

BACKGROUND AND PURPOSE

Pediatric urolithiasis can be managed with various endourologic techniques, which are challenging and demanding. With the availability of advanced minimally invasive techniques, one has to select the appropriate modality. We analyzed the results of various techniques selected prospectively on the basis of our guidelines for the management of pediatric urolithiasis.

PATIENTS AND METHODS

We analyzed the results of percutaneous nephrolithotomy (PCNL), ureteroscopy (URS), and extracorporeal shockwave lithotripsy (SWL) in 45 children treated at our institute between January 2004 and May 2005. There were 35 boys and 10 girls ranging from 12 months to 17 years age (median age 8.2 +/- 5.72 years), with 25 children (55.6%) under the age of 8 years. Stone-free rate, complications, and hospital stay were assessed.

RESULTS

Extracorporeal lithotripsy was performed in 13 children (15 renal units) with average stone surface area of 50.8 +/- 35.8 mm(2). The stone-free rate was 92.3%. The total number of shocks per treatment ranged from 450 to 1400 (mean 856.3 +/- 189.6). A total of 25 PCNLs were done. Stone extraction was completed in a single stage in 20 units (80%), whereas 5 units (20%) required a second stage. Stone-free status was achieved in 23 renal units (95.8%). In the URS group, 9 procedures were planned in 8 children, and rigid ureteroscopy was successful in 6 (66.7%).

CONCLUSIONS

With the availability of various alternative approaches, proper treatment planning and judicious use of minimally invasive techniques can cure most patients. On the basis of our experience and results, we recommend an algorithm for the management of pediatric stone disease.

Minimally invasive treatment of ureteral calculi in children

A retrospective analysis was done to determine the efficacy of shock wave lithotripsy (SWL) and ureteroscopy in the treatment of paediatric ureteral calculi. We reviewed the records of 67 (35 boys, 32 girls) children (71 ureters) admitted to our clinic for treatment of ureteral calculi during 1990-2005. The initial treatment method was SWL in 80.3% (57 ureters), ureteroscopy in 11.3% (eight ureters) and open surgery in 8.5% (six ureters) of the renal units. The mean age of the patients was 10.67 +/- 4.4(1-16) years. The stone-free rates after SWL for upper, middle and lower ureteral calculi were 74.1, 100 and 75.9%, respectively. Increased stone diameter (P = 0.014) and/or burden (P = 0.002) were found to be significant factors that had an adverse affect on the stone-free rate after SWL while the success rates of SWL were independent of location. Including six patients (seven ureters) with failed SWL, a total of 14 patients (15 renal units) subjected to ureteroscopy for lower ureteral calculi yielded a stone-free rate of 93.3%. Thus, the overall stone-free rates after SWL, ureteroscopy and open surgery were found to be 75.4, 93.3 and 100%, respectively. Depending on the stone burden, SWL might be a good option for initial treatment of most ureteral calculi in children. Ureteroscopy offers a high success rate for lower ureteral calculi, including SWL failures.

Extracorporeal shock wave lithotripsy in the management of pediatric urolithiasis

The main objective of this paper was to evaluate the efficacy and safety of the management of pediatric urolithiasis by extracorporeal shock wave lithotripsy (ESWL). Between November 1988 and July 2000, 165 renal stones, 53 ureteral stones, and 5 bladder stones were treated in 126 pediatric patients using Siemens Lithostar lithotriptor. The ESWL treatments ranging from 1 to 7 were needed per patient (mean: 2.1). One ESWL session was performed for 49.6% of stones, two for 24.6%, three for 13.0 %, four for 5.6% and > 4 for 8.2%. The success rate for renal stone units (asymptomatic fragments less than 4 mm) was 88.2%, stone-free rate was 49.0%. The stone-free rate for ureteral stone units was 87.5%, but was 75% for bladder stones. The overall results of ESWL treatment in 126 children was satisfactory: the success rate was 90.5%, stone-free rate was 51.6%, residual fragments > 4 mm were 9.5%. General anesthesia was required in 65 children (136 treatments) under the age of 10, and only in 18 children (40 treatments) in the age 11-14. Auxiliary procedures, such as double J stent and percutaneous nephrostomy (PCN) were used in 19 and 7 patients, respectively. Perirenal hematoma in one patient and hematomas in enteric wall in another one patient were the only major complications managed conservatively without consequences. Low energy lithotripsy with the Siemens Lithostar in our series of pediatric patients was safe and relatively effective.

Clinical Insignificant Residual Fragments (CIRF) after Extracorporeal Lithotripsy: Implications and Treatment

The stone-free status depends on the appropriate selection of the urologic treatment according to the stone and excretory tract characteristics, and/or to the patient parameters.

Although the gold standard for the treatment is the stone-free status, the authors believe that the presence of non-infected, nonobstructive, asymptomatic residual fragments, smaller than 4–5 mm, can be treated with an adequate medical therapy in order to prevent stone growth. Further urological treatment is recommended if the clinical indications for stone removal persist.

Ungated extracorporeal shock wave lithotripsy in children: an initial series

OBJECTIVES

Ungated extracorporeal shock wave lithotripsy (ESWL) is associated with cardiac arrhythmias in adults. However, the incidence of arrhythmias in children undergoing ungated ESWL has not been established. Therefore, we report on the safety and efficacy of ungated ESWL of renal calculi in children.

METHODS

We evaluated all patients younger than 18 years of age who were undergoing ungated ESWL of renal calculi. All patients were monitored for arrhythmias, along with other standard monitoring, by the anesthesiologist.

RESULTS

Eight consecutive children (three boys and five girls) between 3.5 and 17 years of age (median 13.5) underwent 10 ESWL procedures for renal calculi. Of the 10 stones, 9 were located in the left kidney and 1 was located in the right kidney. The stone size ranged from 5 to 19 mm. Six patients underwent 3000 shocks and 2 patients underwent 800 and 2200 shocks. All patients underwent lithotripsy with a gradual incremental energy increase from 17 to 24 kV, except for 1 child (maximum of 18 kV) because of the patient's age (3.5 years). No patient had cardiac arrhythmias or other intraoperative complications. No patient required conversion to gated ESWL. The overall stone-free rate was 90.0% as determined by abdominal radiography and renal/bladder ultrasonography.

CONCLUSIONS

The results of this initial series suggest that ungated ESWL is safe and efficacious in patients younger than 18 years of age. Additional studies are warranted to evaluate further the use of ungated ESWL in the pediatric population.

Factors affecting the success rate of extracorporeal shock wave lithotripsy for renal calculi in children

The aim of the study was to analyse factors affecting the success rate of extracorporeal shock wave lithotripsy (ESWL) in children with renal calculi. We performed a retrospective analysis reviewing records of 85 (40 female, 45 male) children (89 renal units) subjected to ESWL for treatment of renal calculi during 1990-2005 in our department. As 4 patients had bilateral calculi and 19 children (21 renal units) had renal stones at more than one different site, each location was analysed separately for convenience. The mean age of the patients was 10.3+/-4.6 (2-16) years. The stone-free rates for renal pelvis, lower, middle and upper caliceal calculi were 70, 62, 50 and 73%, respectively. A higher rate (33%) of insignificant fragments (< or = 4 mm) was noted for lower pole calculi. Increased stone diameter (P=0.0001) and burden (P=0.04) were found as the most significant factors that adversely affect the stone-free rate for pelvis renalis calculi, whereas an acutely oriented infundibulum and/or a long lower infundibulum (P=0.005) were unfavourable factors for clearance of lower caliceal stones. The stone-free rate in children with multiple calculi was 48%, while 29% of the renal units had retained fragments. ESWL is a good initial option for treatment of most of the renal calculi < 2 cm except in the presence of unfavourable lower caliceal anatomy. Increased stone burden, multiple stones, staghorn calculi, narrow lower infundibulopelvic angle and long lower infundibulum are factors that adversely affect the clearance rate.

Endoscopic management of stones in children

PURPOSE OF REVIEW

Management of pediatric urolithiasis has evolved from open surgery to minimally invasive techniques. With advancements in instrumentation, endourological procedures are being performed more commonly in children. The current article reviews the literature published from January 2003 to September 2004 regarding endoscopic management of stones in children.

RECENT FINDINGS

Whereas recent literature supports shock-wave lithotripsy as the preferred treatment option for pediatric stones, it also confirms the safety of percutaneous nephrolithotomy and ureteroscopy in all age groups. Retrograde intrarenal surgery and laparoscopic surgery are newer additions to the armamentarium of the endourologist but their role needs to be better defined.

SUMMARY

The majority of stones in children can be managed using minimally invasive techniques. Proper treatment planning and use of appropriate instrumentation are important to achieve optimal outcome.

Outcome of small residual stone fragments following shock wave lithotripsy in children

PURPOSE

We evaluate the outcome of small residual stone fragments (RF) following extra-corporeal shock wave lithotripsy (ESWL, Dornier Medical Systems, Inc., Marietta, Georgia) in children.

MATERIALS AND METHODS

The medical records of 39 boys and 44 girls (88 renal units) with urolithiasis who underwent ESWL were reviewed. Median patient age was 7 years. Average stone burden was 14 mm. Mean followup was 46 months. After the first ESWL 40 of the 88 (46%) renal units became stone-free and 18 (20%) had RF 5 mm or less. The remaining 30 (34%) units required further treatment using ESWL or ancillary surgical procedures that rendered 12 of them stone-free and 8 with RF. The 26 renal units with RF constitute our study subjects. Adverse outcomes such as growth of RF, symptomatic episodes or calculi recurrence in stone-free cases were recorded.

RESULTS

Of the 26 renal units with RF 5 mm or less, 18 (69%) had an adverse clinical outcome (symptoms or RF growth) and 8 (31%) patients were asymptomatic and had no stone growth. Patients with RF had a significant increase in adverse clinical outcome compared to stone-free subjects, with an odds ratio of 3.9 (95% CI 1.5-9.6). The presence of metabolic disorders was associated with RF growth (odds ratio 11.4, 95% CI 1.5-79).

CONCLUSIONS

Small RF after ESWL is clinically significant in children and increase the chance of adverse clinical outcome. These patients require close followup, particularly those with identifiable predisposing disorders.

Epidemiology of paediatric renal stone disease in the UK

BACKGROUND

The previous epidemiological study of paediatric nephrolithiasis in Britain was conducted more than 30 years ago.

AIMS

To examine the presenting features, predisposing factors, and treatment strategies used in paediatric stones presenting to a British centre over the past five years.

METHODS

A total of 121 children presented with a urinary tract renal stone, to one adult and one paediatric centre, over a five year period (1997-2001). All children were reviewed in a dedicated stone clinic and had a full infective and metabolic stone investigative work up. Treatment was assessed by retrospective hospital note review.

RESULTS

A metabolic abnormality was found in 44% of children, 30% were classified as infective, and 26% idiopathic. Bilateral stones on presentation occurred in 26% of the metabolic group compared to 12% in the infective/idiopathic group (odds ratio 2.7, 95% CI 1.03 to 7.02). Coexisting urinary tract infection was common (49%) in the metabolic group. Surgically, minimally invasive techniques (lithotripsy, percutaneous nephrolithotomy, and endoscopy) were used in 68% of patients.

CONCLUSIONS

There has been a shift in the epidemiology of paediatric renal stone disease in the UK over the past 30 years. Underlying metabolic causes are now the most common but can be masked by coexisting urinary tract infection. Treatment has progressed, especially surgically, with sophisticated minimally invasive techniques now employed. All children with renal stones should have a metabolic screen.

The impact of radiological anatomy in clearance of lower calyceal stones after shock wave lithotripsy in paediatric patients

OBJECTIVE

To determine the factors affecting stone clearance after extracorporeal shock wave lithotripsy (ESWL) in children with lower calyceal stones.

MATERIALS AND METHODS

Lower pole stone clearance was reviewed in 34 patients aged between 2 and 16 years (23 boys and 11 girls) treated with ESWL between 1989 and 2001 in our clinic. Renal anatomy was determined on standard intravenous urograms. The lower infundibulopelvic angle (IPA) was measured by two different methods based either on measuring the angle between vertical pelvis axis and vertical axis of lower infundibulum or finding the angle between the ureteropelvic axis and vertical axis of lower infundibulum.

RESULTS

The mean age of the patients was 12.1+/-4.16 (2-16) years. The mean stone burden was found as 96.93+/-87.13 mm(2) and the mean shock wave number per session and power as 2631.4+/-593.1 and 17.57+/-1.1 kV, respectively. The stone-free rate was 55.9%. Fifteen (44.1%) cases had residual fragments retained in lower calices after lithotripsy and are still followed. The stone clearance was found to be unrelated to stone burden and infundibulum width (p=0.44 and p=0.34, respectively). However, a significant difference was present between mean lower pole infundibular length (p=0.0032) and lower IPA measurements according to both methods between stone-free cases and others. The most remarkable factor that had a significant influence on stone clearance was an acutely oriented infundibulum defined according to IPA-ureteropelvic axis angle determination method (p=0.00001) followed by Sampaio's pelvic axis method (p=0.0001). Only 1 (5%) patient was stone-free under 40 degrees and 1 (6%) case with an angle of 45 degrees had residual fragments in the former method. Similarly none of the cases had residual fragments over 90 degrees for Sampaio's method and 90% of the stone-free cases had a more obtuse angle. Thus, we determined that a cut-off point of 40 degrees for the IPA-ureteropelvic axis method and 90 degrees for Sampaio's method was most useful to determine the clearance of lower pole fragments.

CONCLUSION

The factors affecting stone clearance in paediatric patients are similar to adults.

[Treatment with shock-wave lithotripsy in children: our experience]

OBJECTIVES

To analyze the efficacy and complication rates of extracorporeal shock wave lithotripsy in the paediatric age group.

PATIENTS AND METHODS

From 1989 to 2000, 29 children (mean age 8 years, range 1-14) underwent ESWL for urinary calculi at our institution. A total of forty-four ESWL sessions were performed in 36 calculi and a previous double pigtail stent was inserted in 11 patients. Intravenous anesthesia was used in the vast majority of cases.

RESULTS

Complete removal of all stone fragments was achieved in 24 (66.7%) renal units after a first session, 6 (16.7%) after a second session. The rest of the patients became stone-free after 3 sessions in 3 patients, open lithotomy in 1 patient and ureteroscopy in another patient. In one case a watchful waiting was decided after the failure of the first session of ESWL. Mean hospital stay was 3.2 days (range 1-11) for each session. Complications appeared in 10 patients: 4 had renal colic, 3 haematuria, 2 fever and 1 subcutaneous hematoma.

CONCLUSIONS

ESWL is a safe and effective treatment for paediatric urolithiasis so it should be considered the first-line treatment.

Urolithiasis in the low birth weight infant: the role and efficacy of extracorporeal shock wave lithotripsy

PURPOSE

Nephrolithiasis in preterm infants rarely requires surgical management. When it persists despite conservative therapy, treatment options are not clearly defined. We report a single institutional experience with extracorporeal shock wave lithotripsy (ESWL)* for the treatment of these small infants.

MATERIALS AND METHODS

We treated 8 infants (mean age 13 months) with a history of prematurity and 9 persistent stones with a Dornier HM3 lithotriptor between 1996 and 1999. Mean weight was 7,700 gm. Of the infants 7 had been treated with furosemide for bronchopulmonary dysplasia and 1 presented with multiple anatomical abnormalities. Gantry modification with a wooden platform and polystyrene foam positioning was used for lung and visceral protection. Ureteral stents were placed in 5 patients before ESWL. Renal ultrasonography was performed before, and 2 and a mean of 8 weeks after ESWL. Stone risk factors in our population were investigated through a multispecialty approach.

RESULTS

Average stone burden was 47.9 mm.2. A total of 9 sessions of ESWL were required for complete fragmentation of the 9 renal stones. A mean total of 2,100 shocks at a mean 16.1 kV. were administered. One patient with bilateral stones was treated in 2 separate sessions after a 4-week interval. No repeat ESWL sessions or other surgical interventions were required in any patient. Renal ultrasonography demonstrated no post-ESWL morphological changes. Practices leading to a higher incidence of neonatal nephrolithiasis at our institution were also identified.

CONCLUSIONS

ESWL is effective treatment for nephrolithiasis in small infants. Short-term safety has been established but continued long-term functional followup is essential. Multifactorial etiologies of nephrolithiasis must be identified and modified promptly in the care of preterm infants.

Extracorporeal shock wave lithotripsy is highly effective for ureteral calculi in children

PURPOSE

Treatment of ureteral calculi in the pediatric population represents a unique challenge. Extracorporeal shock wave lithotripsy (ESWL*) and ureteroscopy have been advocated for the treatment of such stones. We present our experience with ESWL monotherapy for ureteral stones in children in the last decade.

MATERIALS AND METHODS

Between 1989 and 1999 we treated 21 boys and 17 girls with a mean age of 8 years (range 8 months to 14 years) with ureteral stones at our institution. Records were reviewed and analyzed for presentation, metabolic and anatomical anomalies, stone size and location, outcome and complications. Average stone size was 9.5 x 6.5 mm. (range 3 to 32). Stones were in the upper ureter in 17 cases, mid ureter in 2 and lower ureter in 19. All patients underwent ESWL with a Dornier HM3 lithotriptor under general anesthesia. Nephrostomies were placed in an anuric infant with bilateral ureteral obstruction and in 2 patients with nonfunctioning kidneys (4 renal units). Ureteral catheters were used in 15 patients for better identification and localization of the stone during ESWL. The catheters were removed immediately postoperatively.

RESULTS

Of the patients 31 (81.5%) were free of stones after 1 session of ESWL, 5 (13.1%) after 2 and 1 after 3. One patient underwent ureteroscopy for residual fragments after 2 ESWL sessions. The stone-free rate following 1 ESWL session was 100% for ureteral calculi 10 mm. or smaller regardless of location. Of the 12 patients with stones larger than 10 mm. 8 (67%) were free of stones following 1 ESWL session. The overall success rate of ESWL was 97.3%. No child had postoperative urinary infection or ureteral obstruction.

CONCLUSIONS

ESWL is an efficient and safe modality for the treatment of pediatric ureteral stones.

EXTRACORPOREAL SHOCK WAVE LITHOTRIPSY IS HIGHLY EFFECTIVE FOR URETERAL CALCULI IN CHILDREN

PURPOSE

Treatment of ureteral calculi in the pediatric population represents a unique challenge. Extracorporeal shock wave lithotripsy (ESWL*) and ureteroscopy have been advocated for the treatment of such stones. We present our experience with ESWL monotherapy for ureteral stones in children in the last decade.

MATERIALS AND METHODS

Between 1989 and 1999 we treated 21 boys and 17 girls with a mean age of 8 years (range 8 months to 14 years) with ureteral stones at our institution. Records were reviewed and analyzed for presentation, metabolic and anatomical anomalies, stone size and location, outcome and complications. Average stone size was 9.5 x 6.5 mm. (range 3 to 32). Stones were in the upper ureter in 17 cases, mid ureter in 2 and lower ureter in 19. All patients underwent ESWL with a Dornier HM3 lithotriptor under general anesthesia. Nephrostomies were placed in an anuric infant with bilateral ureteral obstruction and in 2 patients with nonfunctioning kidneys (4 renal units). Ureteral catheters were used in 15 patients for better identification and localization of the stone during ESWL. The catheters were removed immediately postoperatively.

RESULTS

Of the patients 31 (81.5%) were free of stones after 1 session of ESWL, 5 (13.1%) after 2 and 1 after 3. One patient underwent ureteroscopy for residual fragments after 2 ESWL sessions. The stone-free rate following 1 ESWL session was 100% for ureteral calculi 10 mm. or smaller regardless of location. Of the 12 patients with stones larger than 10 mm. 8 (67%) were free of stones following 1 ESWL session. The overall success rate of ESWL was 97.3%. No child had postoperative urinary infection or ureteral obstruction.

CONCLUSIONS

ESWL is an efficient and safe modality for the treatment of pediatric ureteral stones.

A fishnet gantry for pediatric extracorporeal shock wave lithotripsy on the Sonolith 3000

A new type of lithotripsy gantry composed of fishnet and bungee cords has been developed to allow proper patient positioning of infants and small children who undergo extracorporeal shock wave lithotripsy on the Sonolith 3000 lithotriptor. The materials are safe, inexpensive, easy to use, and do not interfere with shock wave delivery during a lithotripsy session. The gantry can be used for other lithotripsy machines that have a similar construction with a self-contained waterbath and a large lithotripsy table window.

The management of paediatric urolithiasis

OBJECTIVE

To evaluate the efficacy and safety of the management of paediatric urolithiasis by extracorporeal shock wave lithotripsy (ESWL), endoscopic ureterolithotomy, percutaneous nephrolithotomy (PCNL) and open nephrolithotomy.

PATIENTS AND METHODS

In a 3-year period (1997-1999), 59 children were treated for urolithiasis and underwent a total of 79 procedures. Thirty-two ESWL sessions were performed in 23 children (mean age 7.4 years, median 6.0). PCNL was undertaken in 30 renal units in 25 children (mean age 6.4 years, median 4.0). Eight patients (mean age 7.8 years, median 5) underwent 17 ureteroscopic procedures, six of which involved the use of a holmium laser. Three children with staghorn calculi underwent open nephrolithotomy under conditions of renal ischaemia and hypothermia.

RESULTS

Of the 23 children treated using ESWL, 21 (91%) became stone-free; 17 underwent one ESWL session (74%), three had two sessions and three (13%) had three sessions. All eight patients who underwent ureteroscopy became stone-free. Four patients in whom the stone could not be reached by ureteroscopy initially had a JJ stent inserted, and the stone and stent subsequently removed. Stones were cleared using PCNL in 27 of 30 renal units (90%); three patients who had residual stone fragments were rendered stone-free by ESWL. Two of three children undergoing open nephrolithotomy were stone-free after surgery and the remaining one rendered stone-free with ESWL. Metabolic evaluation showed that 25 of 45 children (55%) had a urinary infection, eight (18%) had hyperoxaluria, three (7%) had hypercalciuria, two (4%) had cystinuria, and no identifiable cause was found in seven (16%). Treatment by a single modality rendered 52 of the 59 children (88%) stone-free; when the different modalities were combined, 57 of 59 patients (97%) were cleared of their stones.

CONCLUSIONS

Technological advances in ESWL, ureteroscopy and PCNL have had a significant effect on the management of urolithiasis in children, allowing a safe and successful outcome. The comprehensive care of children with urolithiasis should include a full metabolic evaluation. Anatomical anomalies contribute to the complexity of many cases, necessitating a close liaison between adult and paediatric urologists, nephrologists and radiologists to optimize stone management in children.

Extracorporeal shock wave lithotripsy in children: experience using two second-generation lithotripters

OBJECTIVES

To assess the value of extracorporeal shock wave lithotripsy (ESWL) in treating paediatric urolithiasis, and to determine factors that may affect the results.

PATIENTS AND METHODS

Using two types of lithotripters (MFL 5000, Dornier MedTech GmbH, Germany, and the Echolith, Toshiba Medical Systems, Japan), 148 children and adolescents (mean age 11.2 years, SD 4.7, range 1-18) were treated for urinary stones. Of these, 137 patients had renal stones and 11 had ureteric stones. The respective mean (SD) stone width and length were 10.2 (4.1) and 12.9 (5.6) mm for renal stones and 7.6 (2.7) and 9.1 (2.7) mm for ureteric stones. The patients were assessed 3 months after treatment and the results compared using the chi-square test to detect factors that might be associated with the stone-free rate.

RESULTS

For those with renal stones, the overall stone-free rate was 86% and the re-treatment rate 64%. The only significant factor associated with the stone-free rate was the transverse diameter of the stone (P = 0.012); there was no significant effect of the type of lithotripter but there was a significant difference in re-treatment rate (P = 0.016) in favour of the MFL 5000. All those with ureteric stones were rendered stone-free and only four required re-treatment. Only one child among those with renal stones developed steinstrasse; this was managed by ureteroscopy and otherwise no other complications were recorded in either group.

CONCLUSIONS

ESWL is a safe and effective treatment for paediatric urolithiasis. The stone-free rate is influenced significantly by stone size. The re-treatment rate differed significantly between the electrohydraulic and piezoelectric lithotripters, but the stone-free rate did not.

Management of residual stones

Stone-free status is highly dependent on selection of the appropriate surgical technique, which should be tailored according to the individual stone and patient parameters. Although a stone-free state is the desired outcome of surgical intervention of urolithiasis, the authors believe that the presence of noninfection, nonobstructive, asymptomatic postprocedural residual fragments can be managed metabolically in order to prevent stone growth adequately. Further surgical intervention in the case of residual fragments is warranted if the clinical indications that prompted the original surgery persist.

Paediatric anatrophic nephrolithotomy; stone clearance - at what price?

OBJECTIVE

To evaluate the functional outcome of anatrophic nephrolithotomy in children.

PATIENTS AND METHODS

All children undergoing anatrophic nephrolithotomy for complex branching and multiple renal calculi over an 11-year period were studied prospectively. Demographic data, treatment details and outcome, as assessed by X-ray, ultrasonography and isotope studies, were recorded. Anatrophic nephrolithotomy was carried out with surface cooling of the kidney followed by nephrostomy drainage for 5-7 days.

RESULTS

Nine children (median age 4 years, range 7 months to 9 years) underwent anatrophic nephrolithotomy. Predisposing factors included urinary tract infection (by Proteus mirabilis) in all and hyper-calciuria in two children. The median (range) total ischaemic time at operation was 25 (15-40) min and the operative duration 150 (120-200) min. Three children required a blood transfusion. Stone clearance was incomplete in one child. There was no recurrent stone formation after a long-term follow-up (median 32 months, range 14-107) in the other patients. Isotope studies showed impaired split renal function (<40%) in six children before surgery; there was a significant decline (>5%) in divided function in five children (range 6-16%) after surgery.

CONCLUSION

Anatrophic nephrolithotomy is an effective means of rendering children with branching calculi stone-free, but this study suggests that it leads to some further parenchymal damage.

The efficacy and parenchymal consequences of extracorporeal shock wave lithotripsy in infants

OBJECTIVES

To determine the efficacy of extracorporeal shock-wave lithotripsy (ESWL) in young children and to evaluate, using renal scintigraphy, any possible adverse effects on renal parenchyma.

PATIENTS AND METHODS

From January 1991 to October 1998, 19 infants (aged 5-24 months) underwent ESWL for kidney urolithiasis using a Sonolith 3000 (14 kV, Technomed Corp, Lyon, France) or a Nova (14-20 kV, Direx Medical Systems, Paris, France) lithotripter. The treatment and its effects were evaluated using a physical examination, conventional imaging (plain abdominal X-ray and ultrasonography) and renal scintigraphy 24 h before ESWL and again at least 6 months after the last session of treatment.

RESULTS

Ten children were rendered stone-free by ESWL after one session and 18 after two sessions. At the follow-up (8 months to 8 years, mean 36 months) no hypertension was recorded and no acquired parenchymal damage was detected with conventional imaging. No scars or significant variation of differential function attributable to ESWL were identified on renal scintigraphy.

CONCLUSION

ESWL is clearly effective for treating infant urolithiasis. There were no renal parenchymal lesions associated with ESWL, even in previously damaged kidneys or after the treatment of staghorn calculi. A long-term follow-up (assessing blood pressure) is mandatory and renal scintigraphy before and 6 months after ESWL in infants is recommended to confirm these results in a larger series.

Mechanical percussion inversion can result in relocation of lower pole stone fragments after shock wave lithotripsy

OBJECTIVES

To determine whether mechanical percussion combined with inversion (MPI) therapy and forced diuresis can move stone fragments out of the lower pole of the kidney.

METHODS

Twelve patients with lower pole residual stone fragments at least 2 weeks after shock wave lithotripsy were treated using the following protocol. Eleven patients received 20 mg of furosemide before MPI therapy. Patients were treated in the prone Trendelenberg position on a pivoting stretcher and given 10 minutes of percussion over the flank using a mechanical chest physiotherapy percussor. Stone location was documented with plain abdominal radiographs before, immediately after, and 2 weeks following MPI therapy. Voided urine was strained immediately after MPI therapy and throughout the study period.

RESULTS

Abdominal radiographs before and after treatment demonstrated movement of fragments out of the lower pole in 11 patients. In 8 patients, the lower pole appeared entirely clear of fragments on the immediate post-treatment film. Four patients passed stone fragments in their first voided urine. Ten patients passed stone fragments during the 2-week follow-up period.

CONCLUSIONS

MPI therapy combined with diuresis can effectively mobilize stone fragments out of the lower pole calyces and appears to aid in the passage of fragments.

Staghorn calculi in children: treatment with monotherapy extracorporeal shock wave lithotripsy

PURPOSE

We evaluated the effectiveness of monotherapy extracorporeal shock wave lithotripsy (ESWLT) for treating children with staghorn calculi.

MATERIALS AND METHODS

From February 1992 to December 1997, 11 boys and 4 girls 14 months to 13 years old (median age 4 years) presented to our institution with staghorn calculi. In these patients ESWL was performed using a Siemens Lithostar-ULTRA with ultrasound stone localization and with intravenous sedation or without anesthesia. Using the Puigvert method the frequency and energy of the shock waves delivered were increased progressively to desensitize cutaneous nerve receptors, making the procedure less painful and improving stone fragmentation.

RESULTS

Overall stones resolved in 11 of the 15 patients (73.3%) after an average of 2 ESWL sessions. Of the 11 patients 7 were stone-free after only 1 session, 2 with fragments less than 5 mm. required no further intervention, and 2 required additional surgery, including percutaneous nephrolithotomy to remove large residual stone fragments in 1 and open renal surgery to remove a cystine staghorn calculus in 1. Ureteral stents were not required in any patients. One case of post-ESWL fever resolved promptly with antibiotics.

CONCLUSIONS

ESWL using the Siemens Lithostar-ULTRA is simple, effective and safe primary treatment in children with staghorn calculi.

Minimally invasive treatment of urinary tract calculi in children

OBJECTIVE

To report experience of a broad multimodality approach to the treatment of calculi in children using extracorporeal shock wave lithotripsy (ESWL), ureteroscopy/laser lithotripsy, lithoclast and percutaneous nephrolithotomy (PCNL).

PATIENTS AND METHODS

The treatment and outcome were reviewed in 43 children managed by a range of minimally invasive modalities, either singly or in combination, between 1990 and 1997. These patients represent a selected group deemed suitable for minimally invasive management during a period of developing experience with these techniques. Of this cohort, six children had previously undergone open stone surgery and contributory metabolic abnormalities were identified in seven. ESWL was the sole treatment modality in 24 children (56%). In five children (12%) ureteroscopy/laser lithotripsy was combined with ESWL, eight (18%) underwent ureteroscopy/laser lithotripsy alone, whilst three with bladder stones were treated with the lithoclast. Combined therapy including PCNL was required in three patients.

RESULTS

Of the 43 children treated, 38 (88%) were rendered stone-free. Metabolic disorders accounted for three of the five cases of residual calculi. Complications requiring intervention occurred in two children (7%) and three subsequently underwent open pyelolithotomy or ureterolithotomy after unsuccessful minimally invasive treatment.

CONCLUSIONS

Used selectively, the range of minimally invasive procedures available for adults, including ureteroscopy and PCNL, can be safely and effectively extended to the treatment of urinary tract calculi in children. The role of open surgery will diminish further with the availability of specialized instruments for paediatric PCNL.

[Extracorporeal lithotripsy in children. Study of its efficacy and evaluation of renal parenchymal damage by DMSA-Tc 99m scintigraphy: a series of 39 children]

AIM

The objectives of the study were to confirm the efficacy of extracorporeal shock wave lithotripsy (ESWL) in infants and children and to evaluate potential long-term renal parenchymal damage by 99m Tc DMSA renal scan.

MATERIALS AND METHODS

Between November 1989 and November 1997, 39 children between 10 months and 17-1/2 years of age (average: 7 years) were treated by extracorporeal shock wave lithotripsy for kidney or ureteral stones with a Sonolith 3000 lithotriptor (Technomed Corp). Forty-six stones were treated. Eight metabolic and 11 urological abnormalities were identified. The evaluation of the treatment and its consequences were based on a clinical examination, conventional imaging and a DMSA renal scan performed 24 h before extracorporeal shock wave lithotripsy and at least 6 months after treatment.

RESULTS

Treatment was successful (stone fragmented and eliminated) in 84.6% at 3 months after one to four sessions. Sixty-one sessions were necessary and two patients underwent open surgery for failed extracorporeal shock wave lithotripsy. Three recurrences were also retreated. At long term follow-up (6 months to 8 years) no incidents of high blood pressure were observed, nor parenchymal lesions imputable to extracorporeal shock wave lithotripsy.

CONCLUSIONS

The efficacy of the extracorporeal shock wave lithotripsy for children is proven. This study also confirms the innocuousness of extracorporeal shock wave lithotripsy for renal parenchyma even in infants. However, long term follow-up and further evaluation with the other categories of lithotriptors are necessary to make definitive conclusions.

Renal stone disease in children

Renal stone disease has been regarded as an uncommon problem in children compared to adults. However, increased awareness of this problem in children may lead to early intervention preventing long-term consequences on the kidney and the urinary tract. This article reviews the epidemiology, pathogenesis, and the most common etiologies of renal stones in children. The clinical features and diagnostic and therapeutic modalities for the specific etiologies are also outlined. Using these guidelines may be helpful not only in the treatment but also in the prevention of renal stones.

99mTechnetium-dimercapto-succinic acid renal scan in the evaluation of potential long-term renal parenchymal damage associated with extracorporeal shock wave lithotripsy in children

PURPOSE

Extracorporeal shock wave lithotripsy (ESWL) has been reported as efficient and safe in children. Because of reports of renal parenchymal damage in adults, this study was designed to assess the effects of ESWL in pediatric kidneys evaluated before and after treatment with (99m)technetium dimercapto-succinic acid (DMSA) renal scan.

MATERIALS AND METHODS

A total of 15 children, 9 months to 15 years old (mean age 6.5 years), underwent ESWL treatment for urolithiasis. Evaluation imaging included plain abdominal radiography, excretory urogram and/or renal sonography. DMSA renal scan was performed 24 hours before ESWL and at least 6 months after treatment.

RESULTS

ESWL was performed in 1 session for 8 patients, 2 sessions for 6 and 3 sessions for 1, delivering a range of 600 to 3,000 shock waves per session. Treatment was successful in achieving stone-free status in 87% of the cases. Long-term followup (1 to 5 years) showed no blood pressure changes. On DMSA renal scan no acquired parenchymal scar was identified at least 6 months after ESWL treatment.

CONCLUSIONS

The efficacy of ESWL in treating pediatric urolithiasis is confirmed. Renal parenchymal trauma associated with ESWL does not appear to cause long-term lesions identifiable by DMSA renal scan.

Minor residual fragments after extracorporeal shockwave lithotripsy: spontaneous clearance or risk factor for recurrent stone formation?

The aim of this study was to follow the fate of residual stone fragments (RF) < 5 mm after extracorporeal shockwave lithotripsy (SWL) over a sufficiently long period to determine how many are spontaneously cleared and after what time interval. A further aim was to clarify their role in clinical outcome and stone recurrence and regrowth. The clinical and radiologic data of 266 patients were analyzed. The patients were followed up for a mean of 387 days. After SWL, 55 patients (21%) had residual fragments < 5 mm in diameter. There were no significant differences between the stone-free patients and those with RF with regard to age, sex, relevant medical history, or SWL treatment. After a mean follow-up of 2.5 years, 12.7% of the residual fragments had not passed spontaneously, but all of them were clinically silent and located exclusively in the lower calices and the proximal ureter. Only 2% of the patients with RF showed stone regrowth, and no stone recurrences were observed within the follow-up period. In conclusion, although a minor pathophysiological role of RF < or = 5 mm cannot be discounted in recurrence and regrowth of kidney stones after SWL, more invasive attempts to clear all minor fragments do not seem warranted.

Pediatric urolithiasis

Urolithiasis in childhood is of diverse etiology requiring carefully planned individualized diagnostic and management protocols. The efficiency in diagnosis and management of urolithiasis in childhood follows a learning curve, especially when using the more recent technical innovations for management of urinary calculi. With current technical sophistication of transurethral and percutaneous techniques and ESWL, management of urolithiasis during childhood should be relatively straightforward as monotherapy using a single modality or as a combined approach with one or more techniques, saving open surgical intervention for situations where the new technology is either unavailable or inappropriate, or when surgical reconstruction of the urinary tract is necessary to forestall recurrent calculus formation. Postoperative morbidity after management of urinary calculi during childhood appears insignificant; calculus recurrence is uncommon. Long-term postoperative follow-up is mandatory, especially after using the newer technical innovations for urinary calculus management during childhood.