Pediatric urolithiasis: medical and surgical management

Comparing the efficacy of extracorporeal shock wave lithotripsy and ureteroscopic lithotripsy in the treatment of proximal ureteral stones in children: A retrospective study

OBJECTIVES

Ureteroscopic lithotripsy and extracorporeal shock wave lithotripsy methods are commonly used in the treatment of proximal ureteral stones. There are no adequate studies showing which method is more effective in children. In our study, we aimed to evaluate and compare the efficacy of two treatment methods, commonly used for proximal ureteral stones in children.

METHODS

A total of 78 patients who underwent ureteroscopic lithotripsy (n = 38) and extracorporeal shock wave lithotripsy (n = 40) due to stones located in the proximal ureter between 2010 and 2021 were included in the study. Demographic data, clinical characteristics, and treatment outcomes were retrospectively analyzed. Kolmogorov-Smirnov, Chi-square, and Mann-Whitney U tests were used for statistical analysis.

RESULTS

There was no statistical difference between the demographic characteristics of the groups, except for the mean age values (p = 0.008). A statistically significant difference was found in favor of the extracorporeal shock wave lithotripsy group in terms of stone-free rates after the first intervention, complication rates requiring intervention, re-intervention rates, and the average number of anesthesia sessions per patient until stone-free status (p = 0.043, p = 0.009, p = 0.017, and p < 0.001, respectively).

CONCLUSIONS

The results of this retrospective study suggest that extracorporeal shock wave lithotripsy is the primary treatment option for single, non-complicated proximal ureteral stones.

Meta-Analysis of the Safety and Efficacy of α-Adrenergic Blockers for Pediatric Urolithiasis in the Distal Ureter

OBJECTIVE

Pediatric urolithiasis is a common condition, and medical expulsive therapy has grown to be accepted by many parents. We carried out a meta-analysis to identify the efficacy and safety of α-adrenergic blockers for the treatment of pediatric urolithiasis.

METHODS

We identified related articles from the PubMed, Embase, and Cochrane Library databases. All published randomized controlled trials (RCTs) describing the use of α-adrenergic blockers and placebo treatment for pediatric distal urolithiasis were involved. The outcomes included stone expulsion rate, stone expulsion time, pain episodes, need for analgesia, adverse events, and related subgroup analyses.

RESULTS

A total of nine RCTs were involved in our study, including 586 patients. We found that α-adrenergic blockers could significantly increase the rate of stone expulsion [odds ratio (OR), 3.49; 95% confidence interval (CI), 2.38-5.12; p < 0.00001], reduce the stone expulsion time [mean difference (MD), -5.15; 95% CI, -8.51 to -1.80; p = 0.003], and decrease pain episodes (MD, -1.02; 95% CI, -1.33 to -0.72; p < 0.00001) and analgesia demand (MD, -0.92; 95% CI, -1.32 to -0.53; p < 0.00001) but had a higher incidence of side effects (MD, 2.83; 95% CI, 1.55 to 5.15; p = 0.0007). During subgroup analyses, different medications (tamsulosin, doxazosin, and silodosin) also exhibited better efficiencies than placebo, except for doxazosin, which showed no difference in expulsion time (MD, -1.23; 95% CI, -2.98 to 0.51; p = 0.17). The three kinds of α-adrenergic blockers also appeared to be better tolerated, except for tamsulosin with its greater number of adverse events (MD, 2.85; 95% CI, 1.34 to 6.03; p = 0.006). Silodosin led to a better expulsion rate than tamsulosin (OR, 0.42; 95% CI, 0.20 to 0.92; p = 0.03). In addition, α-adrenergic blockers increased the stone expulsion rate regardless of stone size and decreased the expulsion time of stones measuring <5 mm (MD, -1.71; 95% CI, -2.91 to -0.52; p = 0.005), which was not the case for stones measuring >5 mm in expulsion time (MD, -3.61; 95% CI, -10.17 to 2.96; p = 0.28).

CONCLUSION

Our review suggests that α-adrenergic blockers are well-tolerated and efficient for treating pediatric distal urolithiasis. We also conclude that silodosin is the best choice of drug, offering a better expulsion rate, but it remains to be evaluated further by future studies.

Factors to predict shock-wave lithotripsy results in pediatric patients and external validation of a nomogram

OBJECTIVE

To evaluate the accuracy of the Dogan nomogram in predicting stone-free (SF) rate after a single shock wave lithotripsy (SWL) session and evaluate factors that predict SWL results in children.

PATIENTS AND METHODS

The study included 68 patients under 18 years of age who had been treated with SWL for radiopaque upper urinary tract stones in our tertiary centre from January 2010 to December 2016. The median age is 50 (6-207) months and median follow-up period is 9 (4-50) months. Patients with known cystine stone disease, abnormal renal anatomy, urinary diversion and multiple stones located in different calyces were excluded like in the original nomogram study. SF status was evaluated by performing plain abdominal radiography and urinary ultrasonography 2 weeks after each SWL session. Patients who were completely free of stones were considered to be SF. Multiple logistic regression analyses were performed to determine the variables affecting SF status. The bootstrap method with 1,000 replicates was used for the external validity of a nomogram developed by Dogan.

RESULTS

SF rates for each SWL session were determined as 54.4% (37/68) for the first session, 33.3% (7/21) for the second session and 55.6% (5/9) for the third session. Overall, the SF rate was 72.1% (49/68). Multiple logistic regression analysis showed positive and significant correlations of age and stone size with risk of SWL failure. The external calibration plot showed a nearly good validation with Dogan nomogram to predict SWL failure in first session.

CONCLUSION

Our study demonstrates that the Dogan nomogram can be used to predict the SF status after one session of SWL in pediatric patients.

Silodosin versus Tamsulosin as Medical Expulsive Therapy for Children with Lower-Third Ureteric Stones: Prospective Randomized Placebo-Controlled Study

AIM

To compare the efficacy and safety of silodosin versus tamsulosin as medical expulsive therapy for stones of lower-third ureter in children.

PATIENTS AND METHODS

This prospective single-blind placebo-controlled randomized study included 167 pediatric patients who presented with distal ureteric stone (DUS) less than 1 cm. Patients were randomized into 3 groups; group I received silodosin 4 mg once daily, and group II received tamsulosin 0.4 mg while those in group III had placebo. The side effects of the used drugs, both rate and time of stone expulsion, and number of pain episodes were compared among the study groups for a maximum of 4 weeks.

RESULTS

Follow-up data of our patients after treatment revealed that the stone expulsion rate was significantly higher and the time to stone expulsion was significantly shorter in group I (89.3%, 12.4 ± 2.3 days) and group II (74.5%, 16.2 ± 4.2 days) compared to group III (51.8%, 21.2 ± 5.6). However, a statistically significant difference between silodosin and tamsulosin groups in favor of the former one was reported regarding the 2 studied items. Meanwhile, pain episodes requiring analgesia were statistically fewer in group I and II in contrast to placebo group. Adverse events were comparable among all groups.

CONCLUSION

Silodosin provides significantly better stone expulsion rate and shorter expulsion time than tamsulosin for treatment of DUS. Both medications showed good safety profiles in children. However, further studies are required on a larger scale to confirm our results. Assessment of drug safety on younger age-group is still needed.

Xanthine calculi in a patient with Lesch-Nyhan syndrome and factor V Leiden treated with allopurinol: case report

Background

Lesch-Nyhan syndrome is a rare inborn error of purine metabolism marked by a complete deficiency of the enzyme hypoxanthine-guanine phosphoribosyltransferase (HPRT). Inherited as an X-linked recessive genetic disorder that primarily affects males, patients with Lesch-Nyhan syndrome exhibit severe neurological impairments, including choreoathetosis, ballismus, cognitive dysfunction, and self-injurious behavior. Uric acid levels are usually abnormally high, leading to kidney and bladder stones which often necessitate urological intervention. Factor V Leiden is an autosomal dominant disorder of blood clotting associated with hypercoagulability, thrombophilia, and renal disease.

Case presentation

We present the first reported case of xanthine calculi in a patient with Lesch-Nyhan syndrome and Factor V Leiden who was treated with allopurinol. A renal ultrasound and CT scan demonstrated bilateral staghorn calculi in the kidneys as well as nephrocalcinosis. Two years earlier the patient underwent cystoscopy with bilateral ureteroscopy and laser lithotripsy, and he was stone free afterwards. The patient subsequently underwent bilateral percutaneous nephrolithotomy (PCNL) and was stone free following the procedure. Patients with endogenous overproduction of uric acid who are being treated with allopurinol have a higher chance of developing xanthine stones.

Conclusions

Pediatricians treating these children should be aware of these rare conditions and promptly manage the potential complications that may require medical or surgical intervention.

Silodosin in the treatment of distal ureteric stones in children: A prospective, randomised, placebo-controlled study

Objectives

To evaluate the possible role of silodosin (a highly selective α_1A-adrenoceptor antagonist) in facilitating the passage of distal ureteric stones (DUS) in children, as the role of α-blockers as medical expulsive therapy is well known in adults.

Patients and methods

In all, 40 paediatric patients (27 boys and 13 girls) diagnosed with unilateral, single, radiopaque DUS of <10 mm were included in the study. Their mean (SD, range) age was 8.1 (2.7, 5–17) years. The patients were randomly divided into two groups: Group A, received silodosin 4 mg as a single bedtime dose; and Group B, received placebo as a single bedtime dose. Ibuprofen was prescribed to both groups on-demand for pain episode relief. Patients were followed up biweekly for 4 weeks. The stone expulsion time and rate, pain episodes, analgesic use, and any adverse effects were recorded.

Results

The mean (SD) stone size in Group A was 6.6 (1.7) mm and in Group B was 6.7 (1.4) mm (P = 0.4). Two patients were lost to follow-up (one from each group), and one patient in Group A refused to complete the study. The stone-free rate at end of the 4-week treatment period was 88.8% in Group A vs 73.6% in Group B (P = 0.4). The mean (SD) stone expulsion time was 7.0 (4.3) vs 10.4 (4.7) days in groups A and B, respectively (P = 0.02). The mean (SD) number of pain episodes requiring ibuprofen was 2.3 (1.4) vs 4.7 (2.6) episodes in groups A and B, respectively (P < 0.001). Adverse effects (headache and dizziness) were recorded in three patients (16.7%) in Group A, which were mild and none of them discontinued treatment, whilst no adverse effects were recorded in Group B.

Conclusions

The data in the present study show that silodosin can be safely used in the treatment of DUS in children for decreasing time to stone expulsion, pain episodes, and analgesic requirement.

The efficacy and safety of adrenergic alpha-antagonists in treatment of distal ureteral stones in pediatric patients: A systematic review and meta-analysis

OBJECTIVE

We carried out a systematic review and meta-analysis to evaluate the efficacy and safety of adrenergic alpha-antagonists as a medical expulsive therapy for ureteral stones in pediatric patients.

METHODS

The PubMed, EMBASE and Cochrane Controlled Trials Register databases were searched up to January 2016. All randomized controlled trials and all cohort studies in which patients were randomized to receive either adrenergic alpha-antagonists or placebo for ureteral stones were identified. The outcome measures assessed were overall stone expulsion rate (primary), expulsion time (secondary), and treatment-emergent adverse events.

RESULTS

Five trials with a total of 406 pediatric patients met the inclusion criteria. According to the doses of adrenergic alpha-antagonists, the pooling effects of adrenergic alpha-antagonists were analyzed, with a higher expulsion rate obtained than in controls, the stone expulsion rate (OR=2.70, 95% CI 1.49 to 4.91, P=0.001). Adrenergic alpha-antagonists statistically did not significantly decrease the number of the stone expulsion time with the placebo, the stone expulsion time (SMD=-4.65, 95% CI -9.76 to 0.45, P=0.07). Safety assessments included common treatment-emergent adverse events (TEAEs) (OR=2.01, 95% CI 0.74 to 5.48, P=0.17). Compared with placebos, there was a higher stone expulsion rate with the adrenergic alpha-antagonists; in addition, fewer adverse effects were observed.

CONCLUSIONS

This meta-analysis may suggest that adrenergic alpha-antagonists are a safe and effective medical expulsive therapy choice for ureteral stones in pediatric patients. As the level of classification of evidence-based medicine, the level of evidence of our article is Ia. But it remains to need a large-scale multicenter randomized controlled study to be further confirmed.

LEVEL OF EVIDENCE

The level of evidence of our study is V.

Mini-percutaneous nephrolithotomy with high-power holmium YAG laser in pediatric patients with staghorn and complex calculi

INTRODUCTION

Shock wave lithotripsy (SWL) is the treatment of choice for most cases of renal lithiasis in children. Some cases, however, are refractory to SWL and may be associated with anatomic and metabolic changes or a large stone burden. In these circumstances, mini-percutaneous nephrolithotomy (mini-PCNL) is an option.

OBJECTIVE

The aim was to assess the safety and efficacy of high-power holmium YAG (Ho:YAG) laser in mini-PCNL for staghorn calculi.

PATIENTS AND METHODS

The clinical records relating to 35 mini-PCNLs (Table) performed between January 2008 and December 2012 in 33 patients (27 boys and 6 girls; mean age 7 years, range 2-18 years) were retrospectively reviewed. Twenty-two (66.7%) of the patients had undergone a previous SWL (28.6% three sessions). The mini-PCNL puncture technique used involved fluoroscopic guidance with the C arm at 0-90° in the supine position. An 18F tract was used. Stone fragmentation was performed with a high-power Ho:YAG laser (Lumenis 100 W).

RESULTS

Ten of the mini-PCNLs (28.6%) were right sided, and 25 were left sided (71.4%). Stones were located in the lower calyceal group in 64% of patients and in the renal pelvis in 50%. The mean stone size was 4.46 cm(2) (range 3-13.20 cm(2)). The number of stones varied between one and 20, and 83.3% were radiopaque. The laser was set at 70 W (range 50-100 W) (3.5 J/pulse with a frequency of 20 pulses/s). The mean surgical time was 150 min. In 78% of patients, complete stone clearance was achieved, and the overall stone-free rate rose to 85% when residual stones were treated with either SWL or retrograde intrarenal surgery. No perioperative complications were seen.

DISCUSSION

There are few reports in the literature concerning the use of a high-power laser for treatment of complex stones and the few that do exist relate to adults have similar results, showing it to be highly effective and safe, with low morbidity. Some limitations of the present study must be acknowledged. It was retrospective and a relatively small number of patients were included. However, randomized prospective studies are required to confirm our findings and conclusions.

CONCLUSION

In the pediatric population, mini-PCNL with high-power Ho:YAG laser is feasible and safe and represents the technique of choice for complex renal stones.

Long-term effects of pediatric extracorporeal shockwave lithotripsy on renal function

Introduction

Extracorporeal shock wave lithotripsy (ESWL) is a well-known and successful treatment modality. In addition, it can be used in premature infants. ESWL is used to treat kidney and ureter stones in children. However, although it is a preferred noninvasive treatment in that setting, there is debate about its long-term effects on growing kidneys in children.

Objectives

To investigate the long-term effects of pediatric ESWL on renal function in light of updated literature.

Methods

PubMed and Medline were searched for studies on ESWL in a pediatric population with keywords including efficacy, child, kidney calculi, ureter calculi, lithotripsy, injury, vascular trauma, and shock waves. The research was limited to the English literature during a period from 1980 to 2014. In total, 3,000 articles were evaluated, but only 151 papers were considered. Only the manuscripts directly related to the reviewed subjects were included in the current study.

Results

However, the acute effects of ESWL in kidney are well-described. Although there are limited studies on the long-term effects of ESWL in children, there is a widespread opinion that ESWL is not affecting renal functions in the long-term.

Conclusion

ESWL is a safe, effective, and noninvasive treatment option in children. Although ESWL can cause some acute effects in the kidney, there is no long-term effect on the growing kidneys of children.

Dissolution therapy versus shock wave lithotripsy for radiolucent renal stones in children: a prospective study

PURPOSE

We prospectively evaluated the efficacy of dissolution therapy and standard shock wave lithotripsy as a noninvasive modality for radiolucent renal stones in children.

MATERIALS AND METHODS

A total of 87 children with radiolucent renal calculi were included in study. Median age was 2.5 years (range 0.5 to 13). Computerized tomography was done to confirm a stone density of less than 500 HU. Median stone length was 12 mm (range 7 to 24). Patients were randomly divided into 2 groups. The medical group of 48 patients received potassium sodium hydrogen citrate at a dose of 1 mEq/kg per day for 1 to 3 months. The shock wave lithotripsy group of 39 patients were treated with a Lithotripter S (Dornier Medtech, Kennesaw, Georgia) while under general anesthesia. Complications in each group were recorded. Patients were considered stone free when imaging within 3 months showed no evidence of stones.

RESULTS

The stone-free rate was 72.9% for dissolution therapy vs 82.1% after a single session of shock wave lithotripsy (p = 0.314). One patient per group experienced a pyelonephritis episode during followup (p = 0.698). Three of the 13 patients in whom medical regimens failed were noncompliant and 5 ingested the medication sporadically.

CONCLUSIONS

Medical dissolution therapy is a well tolerated, effective treatment for radiolucent renal stones in children. It eliminates the need for shock wave lithotripsy in up to 73% of cases.

[Urolithiasis in childhood]

Urinary stone disease is relatively rare in children with an overall incidence of 1-2 %; however, it is often associated with metabolic abnormalities that may lead to recurrent stone formation. Stone analysis and subsequent metabolic evaluation is therefore mandatory for this high-risk group after the first stone event. The objectives of stone management in children should be complete stone clearance, prevention of stone recurrence, preservation of renal function, control of urinary tract infections, correction of anatomical abnormalities and correction of the underlying metabolic disorders. The full range of minimally invasive procedures is available if active stone removal is necessary. The majority of stones in children can be managed either with extracorporeal shock wave lithotripsy which has a higher efficacy in children than in adults, percutaneous nephrolithotomy, ureterorenoscopy or a combination of these modalities while open or laparoscopic surgery is limited to well-selected cases with underlying anatomical abnormalities.

Metabolic risk factors and the effect of metaphylaxis in pediatric stone disease with hypocitraturia

To describe the metabolic risk factors and investigate the effect of prophylaxis based on these factors on long-term recurrence of urolithiasis in pediatric patients with hypocitraturia. One-hundred and twenty-nine pediatric patients who underwent percutaneous nephrolithotomy between January 2008 and June 2011 were evaluated for metabolic risk factors. The patients with hypocitraturia were enrolled in this study and the data were analyzed using statistical methods for a mean period of 2 years for metabolic abnormalities, stone type, and the effect of potassium citrate prophylaxis on stone recurrence. A 24-h urine metabolite analysis revealed one or more metabolic risk factors in 115 (89.2 %) of the patients, whereas 14 (10.8 %) of the patients had no metabolic abnormalities. Eighty-two (63.5 %) of 129 patients had hypocitraturia. Of them, 43 (52 %) were male and 39 (48 %) were female, with a mean age of 9.7 ± 4.9 and 6.7 ± 4.4 (1-16) years, respectively(p = 0.102). Thirty-five (42.7 %) had pure hypocitraturia, and 47 (57.3 %) had two or more metabolic abnormalities. The most common dual metabolic abnormality was hypocitraturia and hypomagnesuria. Seventy-one patients (87 %) with hypocitraturia received medical prophylaxis and continued regularly, whereas 11 (13 %) patients did not receive medical prophylaxis despite being advised to do so. After a mean follow-up of 26.5 ± 9.4 months, the rate of recurrence was 1.4 % in the patients with hypocitraturia who continued prophylaxis and occurred in all of the patients who did not receive prophylaxis (p < 0.001). Calcium oxalate stones (95.2 %) were the most commonly found stones in the stone analysis. Detailed clinical and laboratory evaluations should be performed in children with urolithiasis. Appropriate prophylactic treatment as potassium citrate, should be given to prevent reformation of stones in patient with hypocitraturia.

Minimally invasive percutaneous nephrolithotomy in preschool age children with kidney calculi (including stones induced by melamine-contaminated milk powder)

PURPOSE

This study was undertaken to assess the safety and efficacy of minimally invasive percutaneous nephrolithotomy (mini-PCNL) using ureteroscope and pneumatic intracorporeal lithotripsy in preschool age children with kidney calculi.

METHODS

We studied 27 renal units in 20 patients of preschool age (≤ 6 years) who underwent mini-PCNL at our institute. The mean age was 42.6 months (range 14-68 months). The average stone burden was 1.85 cm (range 0.9-2.8 cm). Eight patients aged 14 to 58 months had been exposed to melamine-tainted powdered formula. The mini-PCNL was performed with an X-ray-guided peripheral puncture. Minimal tract dilatation was undertaken to fit a 14-16 Fr peel-away sheath. Ureteroscope and pneumatic intracorporeal lithotripsy were used to fragment the stones.

RESULTS

Complete clearance was achieved in 23 renal units (85.2 %) with mini-PCNL monotherapy. This has increased to 92.6 % after adjunctive ESWL. The average fall in hemoglobin was 1.28 g/dL. None of the patients required blood transfusion. The median length of hospital stay was 8.2 days. Patients were followed up every 6 months for 2 years. There has been only one recurrence of stone and no long-term complications.

CONCLUSION

Mini-PCNL is a effective treatment for pediatric kidney stones refractory to extracorporeal shock wave lithotripsy, including stones induced by melamine-contaminated milk powder. The "mini-PCNL" technique, which uses ureteroscope and pneumatic intracorporeal lithotripsy, is a safe and feasible modality for treating renal calculi in preschool age children.

Tamsulosin for the management of distal ureteral stones in children: a prospective randomized study

PURPOSE

Based on efficacy demonstrated in the adult population, tamsulosin was evaluated with regard to facilitating ureteral stone expulsion in children presenting with distal ureteric calculi.

PATIENTS AND METHODS

A prospective randomized controlled study involving 61 children with distal ureteric calculi <12 mm was performed. The children were randomly divided into two groups. Group I (study group, n = 33) received tamsulosin and standard analgesia, and Group II (placebo group, n = 28) received standard analgesia and placebo. Patients were offered a closely monitored trial for spontaneous stone passage in the 4-week period prior to definitive therapy. The stone expulsion rate, number and duration of pain episodes, need for analgesia and possible side effects of medications were observed.

RESULTS

All patients completed the study and none were excluded due to side effects. No significant differences were found between the groups for age, gender and stone size. Mean patient age was 8.1 ± 6.8 years. There were 25 females and 36 males. The stone-free rate was 87.8% in Group I (29/33), compared with 64.2% (18/28) in Group II. A mean stone expulsion time of 8.2 and 14.5 days was recorded for Group I and II respectively, and this difference was statistically significant (P < 0.001).

CONCLUSIONS

Medical expulsion therapy for lower ureteric stones is a successful procedure in children. Tamsulosin demonstrated no clinically significant adverse effect, while proving to be a safe and effective treatment option.

Renal stones: evolving epidemiology and management

The incidence of renal stones in adults has increased significantly over time. Although published evidence is somewhat limited, during the last 10 years, there have been reports of 4-fold increase in the number of children evaluated for nephrolithiasis, and of those, a 7-fold increase in diagnosis of stone disease. The etiology of stone formation has shifted over time, with a transition from infectious causes to metabolic causes. It was our goal in this review of the literature on pediatric renal stone disease to further highlight the changing epidemiology and etiology as well as provide a framework for appropriate clinical evaluation and use of diagnostic tools when approaching a patient with suspected renal stone disease. We also provide guidance regarding treatment and prevention of renal stone disease in children.

Pediatric urinary stone disease--does age matter?

PURPOSE

It has been proposed that younger children are less likely to pass renal calculi spontaneously, and that children younger than 10 years are more likely to have an identifiable metabolic abnormality and subsequently a higher risk of recurrence. We report our clinical outcomes in children with urinary calculi, specifically examining these factors.

MATERIALS AND METHODS

We performed a retrospective review of all pediatric patients diagnosed with renal or ureteral calculi at our institution between 2000 and 2007. Of 150 patients evaluated and treated during this period 80 (86 stones) had sufficient followup data to be included. Patients were divided into 2 groups according to age, namely 10 years or younger and older than 10 years. There were 39 patients in the younger group and 41 patients in the older group. Stone size and location, successful passage or intervention, recurrence and 24-hour urine metabolic study results were recorded.

RESULTS

Of the younger cohort stones were ureteral in 43% and renal in 57%. The opposite trend was seen in older patients, with 69% having ureteral and 31% having renal stones (p = 0.02). Mean stone size (greatest dimension) did not differ significantly between the older and younger groups (6.9 mm vs 5.5 mm, p = 0.17). Overall stone passage rate was 34% for younger and 29% for older patients (p = 0.65). No significant mean size differences in passed stones existed between the groups (3.2 mm vs 2.5 mm, p = 0.31). Overall younger vs older ureteral stone passage rate was 37% vs 41% (p = 0.58), and for renal stones it was 32% vs 0%. Stones recurred in 7 younger and 6 older patients.

CONCLUSIONS

Younger children were more likely to present with renal stones, while older children had more ureteral stones. Overall children 10 years old or younger are as likely to pass stones as older children. Renal stones are more likely to be successfully managed expectantly in younger children. Metabolic abnormalities and stone recurrences are observed at similar rates between younger and older children.

Radiolucent renal stones in children: combined use of shock wave lithotripsy and dissolution therapy

OBJECTIVES

To provide a noninvasive efficient modality for the treatment of radiolucent renal stones in children. Uric acid calculi comprise a significant proportion of urinary stones.

METHODS

This study included 24 children (10 girls and 14 boys) with radiolucent renal stones. Of the 24 patients, 5 presented with bilateral renal stones, 8 with multiple stones, 4 with staghorn stones, and 7 with a solitary renal stone. Their age range was 2-12 years (mean 6.3 +/- 2.8). The stone size range was 12-65 mm in the largest diameter. All patients were treated with combined extracorporeal shock wave lithotripsy (ESWL) and medical therapy in the form of urinary alkalization using potassium sodium hydrogen citrate and allopurinol for the treatment of hyperuricosuria. Before ESWL, 3 patients had a percutaneous nephrostomy tube inserted and 2 patients had a ureteral stent placed to relieve obstruction. ESWL was performed with a Siemens Lithostar using either general anesthesia or intravenous sedation. The follow-up period after stone clearance was 12-36 months (mean 26 +/- 7.2).

RESULTS

The stone-free rate of 100% was achieved in all 24 patients after 3 months of combined use of extracorporeal shock wave lithotripsy and dissolution therapy.

CONCLUSIONS

Combined ESWL and dissolution therapy accelerated stone clearance and delayed stone recurrence. The use of ESWL and medical therapy as a combined modality is a safe and effective treatment of radiolucent renal stones in children.

Genetic causes of hypercalciuric nephrolithiasis

Renal stone disease (nephrolithiasis) affects 3-5% of the population and is often associated with hypercalciuria. Hypercalciuric nephrolithiasis is a familial disorder in over 35% of patients and may occur as a monogenic disorder that is more likely to manifest itself in childhood. Studies of these monogenic forms of hypercalciuric nephrolithiasis in humans, e.g. Bartter syndrome, Dent's disease, autosomal dominant hypocalcemic hypercalciuria (ADHH), hypercalciuric nephrolithiasis with hypophosphatemia, and familial hypomagnesemia with hypercalciuria have helped to identify a number of transporters, channels and receptors that are involved in regulating the renal tubular reabsorption of calcium. Thus, Bartter syndrome, an autosomal disease, is caused by mutations of the bumetanide-sensitive Na-K-Cl (NKCC2) co-transporter, the renal outer-medullary potassium (ROMK) channel, the voltage-gated chloride channel, CLC-Kb, the CLC-Kb beta subunit, barttin, or the calcium-sensing receptor (CaSR). Dent's disease, an X-linked disorder characterized by low molecular weight proteinuria, hypercalciuria and nephrolithiasis, is due to mutations of the chloride/proton antiporter 5, CLC-5; ADHH is associated with activating mutations of the CaSR, which is a G-protein-coupled receptor; hypophosphatemic hypercalciuric nephrolithiasis associated with rickets is due to mutations in the type 2c sodium-phosphate co-transporter (NPT2c); and familial hypomagnesemia with hypercalciuria is due to mutations of paracellin-1, which is a member of the claudin family of membrane proteins that form the intercellular tight junction barrier in a variety of epithelia. These studies have provided valuable insights into the renal tubular pathways that regulate calcium reabsorption and predispose to hypercalciuria and nephrolithiasis.

Shock wave lithotripsy is effective and safe for distal ureteral calculi in children

We evaluated the effectiveness of the Siemens Lithostar Modularis lithotriptor for the management of distal ureteric calculi in children. Between 2004 and 2006, 29 children with distal ureteric calculi were treated in our stone center with the Siemens Lithostar Modularis (Siemens Medical Solutions, Inc.) Effectiveness of lithotripsy, retreatment and efficacy quotient rates, and complications were assessed. The series consisted of 18 (62%) boys and 11 (38%) girls with an age range of 1-13 years (average age 7.0 +/- 3.5). Under fluoroscopic guidance, children were treated with a maximum 3,000 shocks at an average of 2.2 +/- 0.3 kV. Mean stone size was 8.2 +/- 3.2 mm (range 4-18). Success was defined as the lack of any visible stone fragments on posttreatment radiological evaluation. The mean number of sessions required was 1.5 +/- 0.8/patient (range 1-4). Complete clearance rate at 3 months was 86.2%. Re-treatment and efficacy quotient rates for distal ureteral stones were 41.4 and 55.6%, respectively. Complications such as urinary tract infection or steinstrasse occurred in 2 (6.9%) patients. Minor complications included petechial skin hemorrhage at the site of entry of shock waves in all patients. Our results show that shock wave lithotripsy for distal ureteral calculi with the Siemens Lithostar Modularis lithotriptor has a high success rate (86.2%) and efficacy quotient (55.6%) with negligible complications in children.

Extracorporeal shock wave lithotripsy in children: Results and short-term complications

AIM

The introduction of extracorporeal shock wave lithotripsy represented an important evolution in urinary tract lithiasis management. The aim of this study is to describe the results of extracorporeal shock wave lithotripsy for the treatment of urinary tract lithiasis in children, focusing on the index of elimination of the calculi and the complications occurring during the procedure and during the following three months.

METHODS

From September 1991 to July 2002, 135 children between one and 12 years, suffering from urinary tract lithiasis underwent extracorporeal shock wave lithotripsy. A retrospective analysis of these patients was carried out.

RESULTS

One hundred and ninety-five calculi ranging in size from 5.0 mm to 20.0 mm were treated, out of which 147 were found in the kidneys and 48 in the ureter. Urinary tract dilation was presented by 30% of the children at the time of the procedure. After extracorporeal shock wave lithotripsy 75.8% of the calculi were eliminated: 64.1% were stone-free and 11.7% had < or = 4 mm stones. Ureteral calculi and 5-10 mm stones responded better than the kidney and 11-20 mm stones (P = 0.027 and P = 0.012, respectively). No differences were detected according to the calculi location, whether in the ureter or kidney (P = 0.637 and P = 0.703, respectively). The shock wave intensity of 14kv was as efficient as the higher voltage. Short-term complications were observed in 23.7%, characterized by fever and pain.

CONCLUSION

In children, extracorporeal shock wave lithotripsy proved to be able to eliminate 75.8% of the treated calculi and 83.7% of the patients presented a complete or partial response. Complications were observed in 23.7% of patients, and pain was the most frequent symptom.

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.

Effect of potassium citrate therapy on stone recurrence and regrowth after extracorporeal shockwave lithotripsy in children

BACKGROUND AND PURPOSE

Stone disease in children may cause functional and morphologic changes in the urinary tract during longer-term follow-up. Prevention of stone recurrence will be possible only with careful metabolic evaluation and appropriate management. The possible preventive effects of potassium citrate therapy on true stone recurrence, as well as regrowth rates after shockwave lithotripsy (SWL), were evaluated in children treated for renal stones.

PATIENTS AND METHODS

Following assessment of the efficacy of SWL, 96 children (72 male, 53 female aged 4 to 14 years with a mean of 6.6 years) were evaluated for the effects of potassium citrate on residual fragments as well as true new stone formation during long-term follow-up. All children had calcium-containing stones with normal renal morphology and function without any urinary-tract infection. Depending on the outcome of treatment, patients with and without residual stones were allocated independently to Group I (N = 52) and Group II (N = 44), which were matched for sex and age. Group I was given oral potassium citrate 1 mEq/kg daily for 12 months; the remaining children served as controls. Follow-up ranged from 12 to 36.6 months, with a mean of 24.4 months. Follow-up results for at least a year with respect to the stone recurrence or stone growth rates were recorded in both groups.

RESULTS

Stone-free children undergoing no specific therapy had significant new stone formation compared with the group receiving potassium citrate on a regular basis (34.6% and 7.6%, respectively). Children with residual fragments receiving no specific preventive measure also showed significant new stone formation, along with enlargement of the fragments.

CONCLUSION

In addition to stone removal, treatment of pediatric urolithiasis requires a thorough metabolic evaluation. Depending on the abnormalities, each patient should be advised on adequate drinking to increase the urine volume in accordance with body size. Although children with hypocitraturia may well benefit from therapeutic agents that raise the urine citrate concentration, our results did clearly show that all children bearing residual fragments should be counseled on adequate fluid intake along potassium citrate treatment to prevent stone regrowth or formation during long-term follow-up.

Efficacy of extracorporeal shock wave lithotripsy for ureteric stones in children

OBJECTIVES

Management of ureteral stones in children represents a challenging problem. In this study, we retrospectively analyzed our experience with extracorporeal shock wave lithotripsy (ESWL) in 192 children with ureteric stones.

METHODS

Between 1990 and 2003, 192 children (<or= 14 years old) with ureteric calculi were treated with the Siemens Lithostar Plus (Siemens Medical Systems, Iselin, NJ). There were 39 stones in the proximal ureter, 19 in the mid-ureter and 134 in the distal ureter.

RESULTS

Mean patient age was 7.3+/-4.1 years (6 months-14 years). There were 122 boys (64.2%) and 70 girls (35.8%). All procedures were performed on an outpatient basis with intravenous sedation in 73 cases (38.1%), general anesthesia in 68 cases (35.7%) and no anesthesia in 51 cases (26.2%). A maximum of 3500 shocks and 18 kV per session were used. A 94% success rate was achieved in proximal (n: 39) and mid-ureteral stones (n: 19). Stone free rates for distal ureteral calculi were 90.6% for stones less than 1 cm in diameter (n: 94) and 91.7% for stones between 1 and 2 cm (n: 26). Overall re-treatment and efficacy quotient rates for proximal ureteral stones were 45.1% and 68.9%, 62.5% and 61.5% for mid-ureteral calculi, and 49.6% and 60.0% for distal ureteral stones.

CONCLUSION

Our results indicate that ESWL with highly satisfactory stone free rates ranging between 90 and 100% and negligible complications can be considered as a first line treatment for ureteric stones in the pediatric age group.

Pediatric urolithiasis: etiology, specific pathogenesis and medical treatment

Pediatric urolithiasis is an endemic disease in certain parts of the world, namely Turkey and the Far East. As a recurrent pathology which may reveal functional as well and morphologic changes in the urinary tract, environmental factors together with urogenital abnormalities should be evaluated thoroughly in each patient. The aims of management should be complete clearance of stones, treatment of urinary tract infections, preservation of renal function and prevention of stone recurrence. In addition to certain minimally invasive stone removal procedures, treatment of pediatric urolithiasis requires a detailed metabolic evaluation in all patients on an individual basis. Obstructive pathologies have to be corrected immediately and children with a positive family history should be followed carefully with respect to a high likelihood of stone re-growth and recurrence. Although specific management of each metabolic abnormality seems to be the key factor in the medical management of stone disease, as general advice each child should be forced to adequate fluid intake which will reveal the urine volume increase in accordance with the body mass index. Moreover, medical therapeutic agents which increase urine citrate levels should be encouraged.

[Evaluation of renal stone disease: metabolic study]

Renal stone formation is a multifactorial process in which all the information obtained from the patient (medical history, imaging tests, stone analysis, metabolic study and physicochemical urine analysis) shows a different facet of the same process. Consequently, all these investigations should be evaluated together. In half of all patients, stone formation is secondary to the presence of metabolic alterations in urine, of which the most frequent is idiopathic hypercalciuria. The second most frequent cause is infection and/or urinary malformations, while hereditary enzyme defects are highly unusual. Reference values for urinary excretion of lithogenic metabolites (calciuria, uricosuria, oxaluria, citraturia, etc.) are essential for an adequate metabolic study, since urinary excretion depends on multiple factors, which have been described in the various publications in the literature. Physicochemical study evaluating saturation of the various salts dissolved in urine should be performed. These saturations are currently considered to be a highly useful index for determining the risk of crystallization and stone formation in patients with lithiasis and for evaluating the effectiveness of treatment. Lastly, the metabolic profile of renal lithiasis in children resembles that in adults, suggesting that predisposition to renal lithiasis begins in childhood. The early detection of the metabolic alterations observed in these patients will reduce the incidence of this disease in both children and adults.

Percutaneous nephrolithotomy for treating renal calculi in children

OBJECTIVE

To report our experience with the percutaneous management of renal stone disease in children.

PATIENTS AND METHODS

The medical and radiological records of children up to 18 years old who were treated for renal calculi by percutaneous nephrolithotomy (PCNL) at our institution between March 1995 and April 2003 were reviewed. For stone removal a special paediatric 18 F access sheath was used.

RESULTS

In all, 26 PCNLs were used in 23 patients (10 boys and 13 girls, aged 1.7-16.8 years). The presenting symptoms were urinary tract infection, abdominal pain and/or haematuria. Of the 23 patients, 17 (75%) had associated metabolic disease or underlying urological anatomical abnormalities. Urinary tract infections were found in 15 patients (65%). The mean (range) stone burden was 6.0 (0.5-18.2) cm2, and the operative duration 127 (50-260) min. The primary stone-free rate was 58%, which increased to 81% after treating residual fragments. One blood transfusion was required and one patient developed urosepsis after PCNL, which was treated with antibiotics.

CONCLUSION

PCNL is an effective alternative for treating renal stones in children, and is the treatment of choice for stones refractory to extracorporeal shock wave lithotripsy.

Results of Shockwave Lithotripsy for Pediatric Urolithiasis

BACKGROUND AND PURPOSE

Shockwave lithotripsy (SWL) is widely practiced in the management of pediatric urolithiasis. However, the efficacy, need for ancillary procedures, and treatment-related complications are not as clearly defined as in the adult population. We reviewed the outcomes of SWL in the pediatric population at our lithotripsy unit.

PATIENTS AND METHODS

A retrospective review of all patients </=16 years of age treated with SWL between January 1991 and June 2002 was undertaken. One hundred patients with 115 stones underwent 131 SWL procedures (115 first treatments, 16 retreatments). The mean age was 10.7 years (range 10 months-16 years). Stone locations were as follows: caliceal 42.6%, renal pelvic 27%, and ureteral (30.4%). The mean stone size was 7.8 mm (range 2-23 mm). Risk factors for stone formation, the need for secondary therapies, and treatment-related complications were noted. The stone-free rate for a single-session SWL procedure, defined as complete absence of stone fragments on plain film, intravenous urography, or renal ultrasonography, was calculated based on 3-month follow-up. The efficiency quotient (EQ) was also calculated.

RESULTS

Risk factors were identified in 31 children (27.0%), including metabolic and anatomic abnormalities. Patients with a risk factor were less likely to be stone free after one SWL session than those without risk factors (31.7% v 64.7%; P < 0.001). General (74.8%), neurolept (24.4%), and epidural (0.8%) anesthesia were utilized. Ureteral stents were placed in 25% of treatments. There were no intraoperative complications. Minor complications were seen in 4.6% of patients. Ancillary procedures were required in 10 patients. Following initial SWL treatment, 60.2% of patients were stone free. The retreatment rate was 13.9%. Following a second treatment, the stone-free rate increased to 68%. The EQ was 54.3.

CONCLUSION

Employing a strict definition of treatment success, single-session SWL in our series offers moderate efficacy in the pediatric population. Patients who have a large stone or risk factor such as an anatomic abnormality are less likely to become stone free and might better undergo an endourologic procedure.

The effect of intracalyceal distribution on the clearance of renal stones of ≥ 20 mm in children after extracorporeal lithotripsy

OBJECTIVES

To determine the effect of the intracalyceal distribution of renal stones on clearance rates after treating paediatric nephrolithiasis with extracorporeal shock wave lithotripsy (ESWL).

PATIENTS AND METHODS

We assessed a retrospective case series of children (aged < or = 14 years) undergoing lithotripsy on an MPL 9000 (Dornier GmbH, Germany) echo-guided lithotripter. Patients were identified using an international coding and indexing system and ESWL registry. In all, 125 children were treated during 1990-2003, but 21 had stones of > or = 20 mm. Stone clearance was assessed at 1 and 3 months, the stone-free state being defined as no radiological evidence of stone or fragments of < or = 3 mm. Failed treatments were analysed to identify any correlation with stone site.

RESULTS

The overall stone-free rate was 81%; in four children the treatment failed (all girls) and subsequently they required ancillary procedures. Nineteen patients (90%) received up to three sessions of ESWL; two required four or more sessions. Of the four children in whom treatment failed, two had JJ stents; the stones were in the lower pole calyx in two, and the renal pelvis and lower pole calyx in two. The mean stone size in those where treatment failed was 25 mm, vs 21 mm in the stone-free group. The complication rate was 19%, but only one child required admission to hospital.

CONCLUSIONS

ESWL is very effective for renal stones in children, with minimal morbidity. Lower pole and partial staghorn stones with a major component in the lower pole calyx should preferably be treated by a percutaneous approach.

Bilateral Renal Calculi: Assessment of Staged v Synchronous Percutaneous Nephrolithotomy

BACKGROUND AND PURPOSE

Percutaneous stone removal has replaced open renal surgery and has become the treatment of choice for large or complex renal calculi. However, patients with large bilateral stone burdens still present a challenge. Simultaneous bilateral percutaneous nephrolithotomy (PCNL) has been demonstrated to be a well-tolerated, safe, cost-effective, and expeditious treatment. We present what is, to our knowledge, the first large retrospective series comparing synchronous and asynchronous bilateral PCNL.

PATIENTS AND METHODS

A chart review was performed on 26 patients undergoing 57 PCNLs for bilateral renal calculi over a 7-year period. Seven patients received synchronous PCNL (same anesthesia; Group 1), and 19 patients underwent asynchronous PNL (procedures separated by 1-3 months; Group 2). Complete surgical and hospital records were available on all patients. The average stone burden for Group 1 was 8.03 cm(2) on the left and 9.18 cm(2) on the right v 10.1 cm(2) on the left and 14.23 cm(2) on the right for Group 2 (P> 0.05). Variables of interest included anesthesia time, operative time, blood loss, transfusion rates, length of hospital stay, and complication rates. Each variable was evaluated per operation and per renal unit. Follow-up imaging with stone assessment was available on 20 patients.

RESULTS

Group 1 required 1.14 access tracts per renal unit to attempt complete clearance of the targeted stones v 1.88 tracts per renal unit in Group 2 (P> 0.05). The average operative time per renal unit was significantly less in Group 1 (83 minutes) than in Group 2 (168.5 minutes) (P< 0.0001), as was blood loss (178.5 mL v 307.4 mL, respectively; P= 0.02). However, blood loss per operation was similar at 357 mL in Group 1 and 282 mL in Group 2. Comparable transfusion rates of 28.6% and 36.8%, respectively, were noted. Forty percent of the patients in Group 1 were completely stone free compared with 36% of the patients in Group 2; however, an additional 50% and 57%, respectively, had residual stone burden <4 mm (P> 0.05). Complications occurred in 2 of 7 operations (28%) in Group 1 and 8 of 42 operations (19%) in Group 2. The total length of hospital stay was nearly doubled for patients undergoing staged PCNL (P= 0.0005).

CONCLUSIONS

These results demonstrate similar stone-free rates, blood loss per operation, and transfusion rates for simultaneous and staged bilateral PCNL. The reduced total operative time, hospital stay, and total blood loss, along with the requirement for only one anesthesia, makes synchronous bilateral PCNL an attractive option for select individuals. However, in patients with larger, less easily accessible stones, excessive bleeding may be encountered more frequently on the first side, thereby delaying management of the second side to a later date. Synchronous bilateral PCNL should be considered in patients in whom the first stage of stone removal is accomplished quickly and safely.

Ureteroscopy for the treatment of urolithiasis in children

PURPOSE

Ureteroscopy for treating urolithiasis in prepubertal children has become more common with the advent of smaller instruments. We reviewed our experience with ureteroscopy for urolithiasis in this cohort of patients as well as the literature using this treatment modality in children.

MATERIALS AND METHODS

Between 1994 and 2000 we performed 27 ureteroscopic stone extractions in 25 children. Ureteroscopy was done in a manner similar to that in adults. Ureteral dilation was performed when necessary to access the ureter. A stent was placed postoperatively if there was significant ureteral trauma.

RESULTS

Of the 25 children 13 were male and 12 were female. Average age was 9.2 years (range 3 to 14). Stones were 2 to 12 mm. in greatest diameter (average 6). Of the 27 procedures the ureteral orifice was dilated before stone treatment in 15 (56%), while in 19 (70%) a stent was placed afterward. No intraoperative and 2 postoperative complications were identified. Overall 92% of the children were rendered stone-free after 1 procedure and 100% were stone-free after 2.

CONCLUSIONS

Ureteroscopy for urolithiasis in prepubertal children is safe and effective. Routine ureteral dilation and ureteral stent placement are not always necessary in these patients.

Unenhanced helical computed tomography for the evaluation of suspected renal colic in the adolescent population: a pilot study

OBJECTIVES

Unenhanced helical computed tomography (UHCT) is rapidly becoming the preferred imaging modality for the evaluation of suspected renal colic in the adult population; however, a series addressing its use in the adolescent population has not been previously published. We assessed the utility of UHCT in the evaluation of suspected renal colic in this age group.

METHODS

Seventeen patients between the ages of 8 and 18 years (mean 14.7) presented to the emergency departments of four hospitals for evaluation of suspected renal colic. All patients were studied with UHCT immediately after initial evaluation. A single helical acquisition was performed from the midpoint of T-12 vertebra to a point below the bladder base, using a slice thickness of 5 mm. Films were reviewed by the institutional radiologist, and results were quantified.

RESULTS

Of the 17 patients who underwent evaluation, no abnormality was detected in 8 patients. A stone was localized in 7 patients who were then appropriately treated. One patient had no stone visualized, but secondary signs suggested a recently passed stone. The final patient had no stone; however, marked bilateral hydroureteronephrosis was noted that led to further evaluation. A single phlebolith was seen in only 1 patient, and no study was nondiagnostic.

CONCLUSIONS

UHCT is a safe, rapidly performed test for the evaluation of suspected renal colic in adolescents. It is highly sensitive and specific for renal and ureteral calculi and, more importantly, allows visualization of alternate pathology. In addition, secondary signs are seen that aid in determining obstruction and are helpful if no stone is visualized. Phleboliths, which can simulate a stone, are rarely seen in adolescence. We believe UHCT allows for rapid triage and localization of stones and should be recommended as the primary diagnostic modality for the evaluation of adolescents with suspected renal colic.

Treatment of distal ureteral stones in children: similarities to the american urological association guidelines in adults

PURPOSE

The American Urological Association (AUA) published clinical guidelines for the treatment of ureteral calculi in adults and note that up to 98% of stones less than 5 mm. in diameter will pass spontaneously. Ureteroscopy and shock wave lithotripsy were acceptable treatment choices for stones less than 10 mm. in diameter in the distal ureter. We reviewed our management of distal ureteral stones in children to see if the AUA Guidelines for adults would apply.

MATERIALS AND METHODS

A total of 14 males and 19 females with a mean age of 12 years (range 0.5 to 17) required hospitalization in the last 6 years for distal ureteral obstruction due to stones. Excretory urography or computerized tomography was performed in all cases, and mean stone size was 4 mm. (range 1 to 15). When stones did not pass spontaneously most patients were treated with ureteroscopic laser lithotripsy.

RESULTS

There were 12 (36%) with a mean age of 11 years and a mean stone size of 2 mm. (range 1 to 3) who passed stones spontaneously with intravenous hydration and narcotics. No child passed a stone 4 mm. or greater spontaneously in this series. Of 21 patients (64%) with a mean age of 12 years and a mean stone size of 5 mm. (range 1 to 15) 2 were treated with ureteral stents, 17 with ureteroscopic lithotripsy and 2 with shock wave lithotripsy. All patients were stone-free at the end of the procedures. The stone composition was predominantly calcium oxalate. Mean followup was 2 years.

CONCLUSIONS

Similar to the AUA guidelines in adults, most stones less than 3 mm. in diameter in the distal ureter of children will pass spontaneously. Stones 4 mm or greater in the distal ureter are likely to require endosurgical treatment. Ureteroscopy and shock wave lithrotripsy have a high success rate for stones between 4 and 15 mm. in the distal ureter. Needle ureteroscope and laser lithotripsy have allowed more stones to be treated safely and effectively in smaller children.

Metabolic evaluation of stone disease patients: a practical approach

In the last three decades, minimally invasive techniques have progressed significantly, replacing traditional open surgery as the mainstay of stone disease surgical treatment. The challenge for the next millennium remains medical prevention of calcium urolithiasis, a field where less dramatic progress has been achieved during the same period of time. The purpose of this article is to provide the practicing urologist with current practical guidelines for the assessment and management of calcium urolithiasis patients. The recommendations are based on the latest available information regarding the pathogenesis, medical treatment options, and decision-making rationale when managing these challenging patients. Every urolithiasis patient should undergo a basic evaluation, which is considered the minimal essential diagnostic work-up, in order to rule out obvious, treatable systemic causes of urinary stone disease. All patients should be advised about conservative nonspecific preventive measures. High-risk stone patients should have a more extensive metabolic evaluation based on two 24-hour urine samples. Treatment protocols for each patient are tailored individually according to the metabolic evaluation findings.

The role of percutaneous nephrolithotomy in the management of pediatric renal calculi

PURPOSE

Minimally invasive techniques for the treatment of urinary calculi in children are recommended due to an increased probability of recurrence. Percutaneous nephrolithotomy is well established in adults but to our knowledge this procedure has not been reported previously in a large series of children. We review our experience with percutaneous nephrolithotomy in children.

MATERIALS AND METHODS

From 1987 to 1995 percutaneous nephrolithotomy was performed in 25 children 3 to 16 years old (median age 8). Indications for percutaneous nephrolithotomy were an obstructed kidney in 10 cases, large stone size or staghorn calculus in 8, failed extracorporeal shock wave lithotripsy in 4 and residual stones after open surgery in 3. There were 15 solitary renal, 4 staghorn and 2 upper ureteral stones, and 5 children had multiple renal calculi.

RESULTS

Percutaneous nephrolithotomy was performed once in 22 patients, and 2, 3 or 5 times in the remainder. Of the 25 patients 17 (68%) were stone-free at hospital discharge or shortly thereafter following a single session of percutaneous nephrolithotomy. Retained calculi after a single percutaneous nephrolithotomy treatment were much more common with staghorn stones (2 of 4 cases or 50%) and multiple stones (3 of 5 or 60%) compared to solitary renal stones (2 of 15 or 13.3%). With subsequent extracorporeal shock wave lithotripsy or repeat percutaneous nephrolithotomy the stone clearance rate was as high as 92%. At a 2 to 66-month followup (average 23) no late complications were noted. Radioisotope scans available in 10 cases before and after percutaneous nephrolithotomy revealed unchanged differential function and evidence of significant renal scars in only 1.

CONCLUSIONS

Percutaneous nephrolithotomy is a suitable and safe procedure for treating renal stones in children.

Urolithiasis in the exstrophy-epispadias complex

PURPOSE

We sought to determine the incidence of urolithiasis in patients with the exstrophy-epispadias complex, associated risk factors and guidelines for the proper clinical management of this problem.

MATERIALS AND METHODS

We retrospectively reviewed the chart and x-rays of 530 patients with the exstrophy-epispadias complex treated at our institution.

RESULTS

Stones formed in 77 of the 530 patients (15%), including 16% of those with classic exstrophy, 25% of those with cloacal exstrophy and 3% of those with epispadias. White and male individuals were most commonly affected. Most calculi formed in the bladder, whether native or augmented by enterocystoplasty. Standard techniques were successful for stone removal. Most calculi consisted of calcium apatite, calcium oxalate monohydrate or magnesium ammonium phosphate, usually in combination with at least 1 other element. The risk of stone formation was associated with augmentation cystoplasty (p < 0.001) and a bladder neck procedure to increase outlet resistance (p < 0.001). Other risk factors included urinary tract infection, foreign bodies, vesicoureteral reflux and urinary stasis but not acidosis or immobilization. Stones recurred in 30 patients (39%), including equal numbers of those treated with open and closed techniques, and recurrence was associated with urinary tract infection or struvite composition (p < 0.05). Serum calcium abnormalities were not present in any patient, including those with metabolic acidosis or prolonged immobilization. Urinary chemistry studies were incomplete or unavailable.

CONCLUSIONS

These data suggest that urolithiasis in the exstrophy-epispadias complex is related to risk factors associated with surgical reconstruction of this condition. The role of metabolic abnormalities that may predispose to urolithiasis is unknown but under investigation. Standard treatment is effective but stone recurrence remains a significant problem. Urine chemistry data may provide information to help minimize stone development in this patient population.

The role of percutaneous nephrolithotomy in the management of pediatric renal calculi

PURPOSE

Minimally invasive techniques for the treatment of urinary calculi in children are recommended due to an increased probability of recurrence. Percutaneous nephrolithotomy is well established in adults but to our knowledge this procedure has not been reported previously in a large series of children. We review our experience with percutaneous nephrolithotomy in children.

MATERIALS AND METHODS

From 1987 to 1995 percutaneous nephrolithotomy was performed in 25 children 3 to 16 years old (median age 8). Indications for percutaneous nephrolithotomy were an obstructed kidney in 10 cases, large stone size or staghorn calculus in 8, failed extracorporeal shock wave lithotripsy in 4 and residual stones after open surgery in 3. There were 15 solitary renal, 4 staghorn and 2 upper ureteral stones, and 5 children had multiple renal calculi.

RESULTS

Percutaneous nephrolithotomy was performed once in 22 patients, and 2, 3 or 5 times in the remainder. Of the 25 patients 17 (68%) were stone-free at hospital discharge or shortly thereafter following a single session of percutaneous nephrolithotomy. Retained calculi after a single percutaneous nephrolithotomy treatment were much more common with staghorn stones (2 of 4 cases or 50%) and multiple stones (3 of 5 or 60%) compared to solitary renal stones (2 of 15 or 13.3%). With subsequent extracorporeal shock wave lithotripsy or repeat percutaneous nephrolithotomy the stone clearance rate was as high as 92%. At a 2 to 66-month followup (average 23) no late complications were noted. Radioisotope scans available in 10 cases before and after percutaneous nephrolithotomy revealed unchanged differential function and evidence of significant renal scars in only 1.

CONCLUSIONS

Percutaneous nephrolithotomy is a suitable and safe procedure for treating renal stones in children.

Treatment update on pediatric urolithiasis

At the doorstep of the twenty-first century the role of extracorporeal shock-wave lithotripsy (ESWL) as the treatment of choice for more than 80% of all stones in children is established. ESWL is safe and effective, with very few differences in success rates being observed among different lithotriptors. The present problem with ESWL appears to be the residual stone fragment, which has a proven clinical significance. A thorough metabolic evaluation and metaphylaxis is indicated in all children, and this will enable physicians to deal with the residual fragments in a more cause-specific manner and prevent regrowth. Another subject that needs prospective randomized studies to be unveiled is the assumption that a specific or universal metaphylaxis, possibly with alkaline citrates, will enhance stone clearance, lower the incidence of residual stone fragments, and optimize the ESWL results. Finally, both percutaneous nephrolithotomy and ureteroscopic stone removal have been established in children as safe and effective treatment options. This gives the clinician the opportunity to choose from a wide range of treatment alternatives, including open surgery, and only this approach will ensure 100% stone removal in individual patients along with the prevention of recurrence and, thus, the elimination of long-term morbidities in this vulnerable patient population.