Pediatric urolithiasis

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.

Percutaneous nephrolithotomy in children: early and late anatomical and functional results

PURPOSE

We report our experience with percutaneous nephrolithotomy (PCNL) in children, and evaluate its early and late anatomical and functional results.

MATERIALS AND METHODS

A total of 65 children with renal calculi were treated with PCNL. Patient age at operation ranged from 9 months to 16 years (mean +/- SD of 5.9 +/- 0.9 years), and 27 (41.5%) were younger than 5 years. Seven patients had bilateral renal stones and, therefore, the number of kidneys treated by PCNL was 72. The patients were followed regularly every 3 months during year 1 and every 6 months thereafter. Renal scans using technetium dimercapto-succinic acid for detection of renal scarring and technetium diethylenetetramine-pentaacetic acid for determination of selective glomerular filtration rate (GFR) were performed in all patients at least once during followup, which ranged from 6 to 72 months (mean +/- SD 40 +/- 10).

RESULTS

Early complications included significant intraoperative bleeding in 1 case, renal pelvis perforation in 1 and transient fever in 2. Mean hospital stay +/- SD was 3 +/- 1.2 days (range 2 to 21). Of the renal units 62 (86%) were stone-free after a single PCNL, and the remaining 10 with residual stones were treated with a second look PCNL (4) and shock wave lithotripsy (6). Stone-free rates at hospital discharge and at 3 months were 93% and 100%, respectively. During followup 6 patients (9%) had recurrence of small renal stones and were successfully treated with shock wave lithotripsy. None of the kidneys had scarring on dimercapto-succinic acid renal scan. All of the kidneys except 1 showed improvement or stabilization of the corresponding GFR determined by diethylenetetraminepentaacetic acid renal scan. Comparison of the mean preoperative GFR of the corresponding kidney (28.8 +/- 11.2 ml per minute) with mean value at followup (36.1 +/- 9.9) showed an increase of statistical significance (p <0.01).

CONCLUSIONS

PCNL is a safe and effective procedure for the treatment of children with renal calculi. At long-term followup the procedure improves renal function without renal scarring.

THE IMPACT OF CALICEAL PELVIC ANATOMY ON STONE CLEARANCE AFTER SHOCK WAVE LITHOTRIPSY FOR PEDIATRIC LOWER POLE STONES

PURPOSE

The clearance rather than stone disintegration of lower pole stones after shock wave lithotripsy (SWL) is significantly inferior according to the other localizations of the kidney. We retrospectively evaluated the impact of caliceal pelvic anatomy on stone clearance after SWL for pediatric lower pole stones.

MATERIALS AND METHODS

We treated 163 renal units (RUs) in children 16 years old or younger with SWL between March 1992 and February 2002. In 36 RUs stones were localized in the lower calices. All patients were treated with sedoanalgesia except 3 (8%) who were treated under general anesthesia. Patients were evaluated by excretory urography and ultrasonography 12 weeks after the last session, and were designated as stone-free or with residual stone. The lower infundibular length, width, length-to-width ratio, pelvic caliceal height and lower infundibulopelvic angle were determined on standard excretory urography before SWL. All measurements were done by 1 urologist who was unaware of the results. Statistical analysis was performed with chi-square, Fisher's exact and Mann-Whitney U tests. ROC analysis was done to determine the cutoff points of caliceal anatomy measurements for stone clearance.

RESULTS

We treated 36 RUs in 23 males and 10 females with isolated lower caliceal stones. Median patient age was 10.5 years (range 2 to 16). Median stone burden was 0.7 cm (range 0.2 to 4), and median number of shock waves and energy used for the entire patient population was 1,500 and 17.2 kV, respectively. Overall stone-free rates for the 36 RUs were 61% after a median treatment session of 1 (range 1 to 7) and retreatment rates were 39%. Of the patients rendered free of stones 13 (59%) were treated in a single SWL session and 9 (41%) underwent 2 or more sessions. Median lower infundibular length, width, length-to-width ratio and pelvic caliceal height in the stone-free and residual stone group were 25.5, 28.0 mm, 4.5, 5.0 mm, 6.4, 5.5 mm and 21.5, 21.5 mm, respectively (p = 0.810, 0.327, 0.511 and 0.511). Median lower infundibulopelvic angle in the stone-free and residual stone groups was 92.50 and 92.50 degrees, and 60.0 and 54.50 degrees, respectively (p = 0.860 and 0.089). On ROC analysis no parameter predicting stone-free rate and cutoff points of caliceal anatomy measurements for stone clearance was found.

CONCLUSIONS

Our results suggest that caliceal pelvic anatomy in pediatric lower pole stones has no significant impact on stone clearance after SWL. There was a highly significant relation between retreatment rates and stone burden, which should be considered for determining the treatment modality.

Transperitoneal laparoscopic pyelolithotomy after failed percutaneous access in the pediatric patient

PURPOSE

We present our experience with transperitoneal laparoscopic pyelolithotomy in pediatric patients in whom percutaneous renal access failed and the stone burden warranted open intervention.

MATERIAL AND METHODS

A transperitoneal laparoscopic approach was used for pyelolithotomy in 8 patients 3 months to 10 years old (mean age 4 years). Percutaneous access failed secondary to a nondilated system and/or an occluding lower pole calculus. Inclusion criteria were failed percutaneous access secondary to a nondilated system and/or stone occlusion of the lower pole system and failed shock wave lithotripsy or a stone burden of greater than 2.5 cm2. A posterior pelviotomy was made. Stones in the renal pelvis were removed with rigid graspers under direct laparoscopic vision. A flexible cystoscope was introduced through a port if caliceal stones were present. The renal pelvis was reconstructed. A watertight anastomosis was verified.

RESULTS

Average operative time was 1.6 hours (range 0.8 to 2.3). Mean hospital stay was 2.15 days (range 2 to 3). A range of 1 to 3 stones (median of 1) were removed and the mean stone burden was 2.9 cm2. No intraoperative complications were noted. Stone analysis revealed 3 patients with calcium oxalate stones, 1 with a calcium phosphate stone and 4 with cysteine stones. There was 1 patient with stone recurrence at a mean followup of 12 months (range 3 to 20). Thus, the overall long-term stone-free rate was 87.5%.

CONCLUSIONS

Transperitoneal laparoscopic pyelolithotomy is feasible when percutaneous access fails and open pyelolithotomy is considered due to a large stone burden.

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.

Percutaneous nephrolithotomy for complex pediatric renal calculus disease

BACKGROUND AND PURPOSE

Pediatric renal calculus disease has been a management dilemma in view of the concern about the effects of the various treatment modalities on the growing kidney, the significant recurrence rate, and the long-term outcome. We report our experience with percutaneous nephrolithotomy (PCNL) monotherapy in staghorn or complex pediatric renal calculi.

PATIENTS AND METHODS

We retrospectively analyzed the case records of 116 patients younger than 15 years who underwent PCNL. The stones included 56 complex calculi. We defined complex calculi as either staghorn (complete or partial) or those with a large bulk and involving more than one calix, the upper ureter, or both.

RESULTS

Complete clearance was achieved in 50 patients (89.8%). Of these, 22 (39%) required a single tract, while 34 (61%) required multiple tracts. With subsequent SWL, the clearance rate increased to 96%. The average hemoglobin drop was 1.9 g/dL. Assessing the factors affecting the hemoglobin drop, the number of tracts and the size of tracts were found to be significant (P<0.01). The average change in the serum creatinine concentration between the preoperative and postoperative measurements was +0.03 mg/dL and was not different in patients with a single tract and those with multiple tracts (+0.02 and +0.04 mg/dL, respectively; P=NS). Intravenous urography done in 36 renal units postoperatively revealed good function in all. A DMSA renal scan in six children showed no scar.

CONCLUSIONS

Monotherapy with PCNL is safe and effective in the management of staghorn and complex renal calculi in single hospital stay. Ultrasound-guided peripheral caliceal puncture and limiting the tract dilatation to 22F are important factors in reducing the blood loss. Multiple tracts increase the hemoglobin drop but are not associated with an increased risk of complications (bleeding, postoperative infection, and prolonged urinary leak). Also, there is no deterioration in renal function after either single- or multiple-tract PCNL.

Pediatric urolithiasis--evaluation of risk factors in 95 children

OBJECTIVE

Pediatric urolithiasis is a rarely encountered pathology, except in endemic areas such as Turkey. As a recurrent pathology which may reveal functional as well and morphologic changes in the urinary tract, metabolic and environmental factors, in addition to urogenital abnormalities, should be evaluated thoroughly in each patient. In this prospective study, the patient and family histories of 95 children with stone disease were evaluated, together with serum and urine risk factors.

MATERIAL AND METHODS

Between 1996 and 2001, 95 children (25 females, 70 males; mean age 7.3 years; age range 0.6-15 years) referred to our department with urolithiasis were evaluated. All patients were investigated with respect to stone localization, associated abnormalities, urinary tract infection (UTI), positive family history and serum and urine risk factors. In addition to standard risk factors (hypocitraturia, hypercalciuria, hyperoxaluria, hyperuricosuria, hypomagnesuria), diet and 24-h urine volume were also assessed in all children. Children with cystinuria were excluded from the study.

RESULTS

Stone size ranged from 0.3 to 3.3 cm, with an average value of 2.0 cm. The localization of the stones was classified as unilateral single stone in 37 patients, multiple unilateral stones in six and bilateral multiple stones in 27. Hypocitraturia was the commonest risk factor detected in our patients. A positive family history was present in 51 cases (54%). In addition, UTI was present in 59 cases (62%) and 67 cases had a previous history of recurrent UTI. Associated urogenital abnormality was detected in nine cases (9.4%). There were significant correlations between stone size and urinary citrate excretion (p < 0.05) and between the presence of UTI and urinary phosphate excretion (r = 0.59, p = 0.047). Treatments used were open surgery in seven (7.3%) cases, extracorporeal shock-wave lithotripsy in 39 (41%) and endoscopic surgery in 20 (21%). Following these procedures, 39 (41%) patients were completely stone-free, 11 (11%) had residual stones (<5 mm in diameter) and 12 (14.8%) passed the stone(s) spontaneously. During follow-up, regrowth was seen in four (4.2%) patients and stone recurrence was noted in a further four (4.2%).

CONCLUSIONS

In addition to stone removal, treatment of pediatric urolithiasis requires a thorough metabolic and environmental evaluation of all patients on an individual basis. Obstructive pathologies have to be corrected immediately and apparent metabolic abnormalities should also be treated. Children with a positive family history should be followed carefully with respect to stone recurrence. Urine volume increases in parallel with body mass index and medical therapeutic agents which increase urine citrate levels should be encouraged.

Extracorporeal shock wave lithotripsy as first line treatment alternative for urinary tract stones in children: a large scale retrospective analysis

PURPOSE

Management of urinary tract stones in children represents a challenging problem. In this study we retrospectively analyzed our experience with extracorporeal shock wave lithotripsy (SWL) in children.

MATERIALS AND METHODS

During a 12-year period 408 urinary tract calculi in 344 children (mean age 8.7 +/- 3.9 years, range 6 months to 14 years) were managed with the Lithostar Plus lithotriptor (Siemens Medical Systems, Iselin, New Jersey). There were 57 caliceal stones, 167 in the renal pelvis, 31 in the proximal ureter, 16 in the mid ureter and 121 in the distal ureter, and 16 bladder stones.

RESULTS

All patients were treated on an outpatient basis, with intravenous sedation being used in 138 (40.1%), general anesthesia in 132 (38.4%) and no anesthesia in 74 (21.5%). A maximum of 3,500 shocks and 18 kV per session was given. A total of 780 SWL sessions were applied (mean 1.9 sessions per stone). Overall, a stone-free rate of 79.9% and clinically insignificant residual fragments in 13.2% of cases were observed at 3-month followup with a re-treatment rate of 53.9%. Overall efficacy quotient was 50.9%. Significantly more favorable results were achieved in ureteral calculi and stones 2 cm or smaller (p <0.05). Complications were observed in 33 patients (9.6%).

CONCLUSIONS

Our results indicate that SWL, with satisfactory stone-free rates and efficacy quotients in stones 2 cm or smaller can be offered as a first line treatment in children.

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.

Extracorporeal shock-wave lithotripsy for treatment of ureteral calculi in paediatric patients

Our objective was to determine the efficacy of extracorporeal shock wave lithotripsy (ESWL) in the treatment of paediatric ureteral calculous disease. We reviewed the records of 41 (23 boys, 18 girls) paediatric patients admitted to our clinic for the treatment of ureteral calculi between between 1989-2001. Patients' age varied between 4-16 years. The majority of the patients, 38 (92.7%) cases were treated initially with ESWL whereas 3 (7.3%) cases were subjected to ureterolithotomy. The mean age of the patients was found as 12.8+/-3.86 (4-16) years. Most calculi were located at either upper or lower ureter. The mean stone burden was 45.16+/-30.65 mm2 and the mean shock wave number per session and power as 2826.72+/-605.18 and 17.69+/-1.11 kV respectively. Minor complications included skin ecchymosis at the site of entry of shock waves in all cases and renal colic that responded to analgesics and emetics in 3 (7.9%) patients. The overall stone-free rate after ESWL was found to be 81.6%. Two (5.3%) cases have residual fragments that escaped to lower calices after lithotripsy for upper ureteral calculi and are still followed. There were 5 (13.2%) failures who were treated with ureterolitotomy for 1 upper and 1 lower ureteral calculi and with ureteroscopy for the rest. It appears that ESWL is still a good option for the initial treatment of most ureteral calculi in children as it is less invasive than ureteroscopy and has a high success rate as a first-line therapy.

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.

Metabolic evaluation of children with urolithiasis: are adult references for supersaturation appropriate?

PURPOSE

We determined the incidence of urinary stone risk factors in pediatric patients with urolithiasis.

MATERIALS AND METHODS

Between 1998 and 2001, 71 children with urolithiasis at 2 pediatric institutions underwent metabolic evaluation. The 24-hour urine samples were analyzed outside central laboratory using adult and known pediatric references. Supersaturation and traditional metabolic parameters were determined and compared.

RESULTS

All patients had metabolic abnormalities. Calcium related abnormalities were present in 92% of children, calcium oxalate supersaturation was abnormal in 69%, calcium phosphate supersaturation was elevated in 70% and traditional calcium parameters were abnormal in 80%. While 11% of the patients had abnormal calcium phosphate or oxalate supersaturation with normal traditional calcium parameters, 10% had normal calcium oxalate or phosphate supersaturation with abnormal traditional calcium parameters. Low urinary volume was identified in 75% of the children.

CONCLUSIONS

Metabolic abnormalities are extremely common in pediatric patients with urolithiasis. Calcium related abnormalities are the most common abnormality. Urinary supersaturation values are complementary to traditional metabolic parameters and may be more sensitive predictors of recurrent stone risk. It is important to establish pediatric reference ranges to interpret these data more accurately.

[Extracorporeal shock-wave lithotripsy. An established treatment]

Extracorporeal shock wave lithotripsy (ESWL) is the most required urinary stone therapy in our country and in the rest of the world. In a way it has replaced the alternative treatments (open surgery, percutaneous nephrolithectomy, ureteroscopy). Nevertheless these therapeutic approaches have still its own indications. Although there is no a definitive agreement, it should be desirable a world-wide consensus where each therapy will have a exactly defined land with all potential of each management improved. We review ESWL technical aspects, its literature-based most accepted indications, adverse bioeffects and last, future improvements are considered.

Percutaneous nephrolithotomy in the management of pediatric renal calculi

BACKGROUND AND PURPOSES

In the era of extracorporeal shockwave lithotripsy (SWL), there are still some patients who will require percutaneous nephrolithotomy (PCNL). Our experience with this procedure is reviewed and discussed.

PATIENTS AND METHODS

Fifty five patients with a mean age of 7.9 years (10 months-14 years) underwent 67 PCNL procedures on 62 renal units between September 1997 and April 2001. Of the patients, 13 had previous open renal surgery, 4 had a solitary kidney, 4 were SWL failures, 2 had osteogenesis imperfecta, one had anuria secondary to bilateral calculi, 2 had poorly functioning kidneys, and 1 had cystinuria (complete staghorn calculus). One disabled patient with neurologic disorders who had multiple stones underwent PCNL in order to decrease the stone burden and to improve the kidney function. Operations were performed under the guidance of monoplane fluoroscopy. Pneumatic or ultrasonic lithotripsy and forceps extraction were used with a rigid nephroscope or ureteroscope (as an alternative instrument in small-caliber tracts).

RESULTS

Excluding the patient with neurologic disorders, 53 of the renal units (86.9%) were stone free at the time of discharge, and the success rate was 96.7%, with six patients having insignificant residual fragments after the procedure. In one patient, open surgery was required, and the other patient was sent for SWL treatment. There was no contiguous organ injury, but in 16 procedures (23.9%), intraoperative hemorrhage was seen, and blood transfusions were required.

CONCLUSION

Pediatric urolithiasis is usually a result of metabolic abnormalities and urinary tract infection, and there is always a risk of recurrence that may necessitate multiple additional intervention. Therefore, PCNL must be considered in selected cases by urologists who are experienced in adult percutaneous procedures.

[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.

Pediatric urolithiasis

Pediatric stone disease is a frequently underestimated entity that can present unique problems in its management. The condition stems from any of a number of underlying, causative factors, and the significant possibility of recurrence must always be borne in mind. The primary care physician should be aware that the condition is readily treatable by an experienced pediatric urologist who has a range of treatment modalities at his or her disposal; however, overall success is governed by a timely referral and subsequent long-term follow-up to ensure the maintenance of a stone-free state.

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.

Percutaneous nephrolithotomy in older children

PURPOSE

The aim of this study was to evaluate the safety and efficacy of percutaneous nephrolithotomy (PCNL) in pediatric patients, older than 8 years, without any technical and instrumental modifications.

METHODS

The authors retrospectively evaluated the data of 16 percutaneously treated kidneys of 14 patients with a mean age of 11 years (range, 8 to 17). The mean stone burden was calculated as 301 mm2 (range, 120-750). Percutaneous accesses were done under fluoroscopic control, and 24F to 30F Amplatz dilators were used depending on patient size. Ultrasonic and laser lithotripsy were performed to fragment calculi.

RESULTS

Mean operating time was 111 minutes (range, 60 to 210 min) and no intraoperative or postoperative major complication was observed. Mean hemoglobin drop after the procedure was 1.16 g/dL (range, 0.3 to 2.8). Blood transfusion was required in only 1 patient, and mean postoperative hospitalization was 4.6 days (range, 3 to 10). Stone-free rate was calculated as 69% (11 of 16), but with residual fragments smaller than 4 mm, the success rate becomes 100% at patient's discharge.

CONCLUSIONS

PCNL is an effective and safe form of therapy in pediatric stone disease. Especially in older children the use of the same instruments and technique as in adults may achieve equal results without any increased risk of possible morbidity and need of blood transfusion.

Characteristics of pediatric urolithiasis in south-east Anatolia

BACKGROUND

Urolithiasis is endemic in Turkey and characteristics of urolithiasis vary in different regions of the world. The aim of the present study was to evaluate the etiological and clinical characteristics and course of pediatric urolithiasis in south-east Turkey.

METHODS

The study population consisted of 81 children (52 girls) with urolithiasis at a mean age of 6.2 +/- 4.2 years who were followed up for 1-32 months.

RESULTS

Metabolic disorders, anatomical defects and infection stones were found to be the etiological factor in 34.6, 29.6 and 22.2% of patients, respectively, while 13.6% of patients were considered idiopathic. Of all patients, 28.4% were admitted with acute renal failure (ARF) and 72.8% had urinary tract infection. Recurrence was seen in 19.8% of patients at presentation. The localization of the stone was found to be in the upper urinary tract, the lower urinary tract or both in 65.4, 14.8% and 17.3% of patients, respectively. Patients with multiple and bilateral stones had a higher risk for ARF than the others. The risk for chronic renal failure was significantly higher in children with multiple, bilateral or recurrent stones and with ARF at presentation.

CONCLUSIONS

Early diagnosis and management of renal stones and urinary tract infections is necessary to prevent the development of ARF or chronic renal failure and to improve the quality of a patient's life.

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.

Percutaneous management of renal calculi: experience with percutaneous nephrolithotomy in 60 children

PURPOSE

We report our experience with percutaneous nephrolithotomy in a pediatric population in which primary as well as recurrent stone episodes are frequent and the need for less invasive procedures is imperative.

MATERIALS AND METHODS

Percutaneous nephrolithotomy was performed in 60 children 3 to 13 years old (average age 6), including 44 boys (73.3%) and 16 girls (26.7%). There was a single obstructing renal calculus in 43 patients, while 17 had multiple calculi. The procedure was performed in 1 stage in 49 patients, and it was staged with preliminary nephrostomy in 11 who presented with calculous anuria and elevated serum creatinine. Normal saline was used as an irrigant and perioperatively serum electrolytes were measured to monitor fluid absorption in 18 patients. Stones were extracted intact from 40 patients (66.6%) and ultrasonic lithotripsy was performed in 20 (33.3%).

RESULTS

Of the 60 patients 50 (83.3%) were rendered stone-free at 1 session. Incomplete stone clearance at 1 session was due to intraoperative bleeding requiring blood transfusion, extravasation, multiple stones that were inaccessible via 1 tract, displacement of stone fragments into an inaccessible calix and insignificant residual fragments less than 3 mm. in 2 cases each. During followup of 3 months to 6 years (average 1 year) no late complications were noted.

CONCLUSIONS

Percutaneous nephrolithotomy is a safe and relatively efficacious mode of managing pediatric renal calculi. Although higher success rates are achieved in adults, caution should be exercised in children, in whom diligent attempts at stone clearance in 1 session may be made at the expense of safety.

Pediatric percutaneous nephrolithotomy: assessing impact of technical innovations on safety and efficacy

OBJECTIVES

To assess the safety and efficacy of percutaneous nephrolithotomy (PCNL) in the pediatric age group and the impact of certain technical modification on the ultimate outcome.

PATIENTS AND METHODS

We studied 45 renal units in 40 patients under 15 years of age who underwent PCNL at our institute. The average age was 9.2 years (range 11 months-15 years). There were 5 bilateral, 11 multiple, and 9 staghorn calculi. The average calculus size was 2.04 (0.9-4.5) cm. The PCNL was done with an ultrasound-guided peripheral puncture, a planned staged approach in some cases, and minimal tract dilatation with the use of a pediatric nephroscope and a specially designed slender probe for pneumatic intracorporeal lithotripsy.

RESULTS

Complete stone clearance was achieved in 41 of the 45 renal units, giving an overall clearance rate of 91%. Minor pyrexia (<100 degrees F/<2 days) was seen in 10 patients, whereas serious pyrexia was seen in 5. One patient had a prolonged leak from the nephrostomy site, which responded to double-J stenting, and one patient had a pelvic perforation with hyponatremia, which responded to conservative treatment. The average fall in hemoglobin was 1.6 g/dL, but none of the patients required blood transfusion.

CONCLUSION

We believe that our alterations in the standard technique of PCNL with the use of pediatric instruments can make it a safe and effective option in the modern management of pediatric urolithiasis.

Extracorporeal shockwave lithotripsy in the pediatric population

BACKGROUND

Shockwave lithotripsy (SWL) is being used increasingly as a therapeutic modality for childhood urolithiasis. We reported our experience and results of SWL in the pediatric population.

METHODS

The 59 renal units (RU) of 54 patients were retrospectively reviewed. The mean patient age was 10+/-3.5 years. All patients were treated with the Lithostar lithotripter in outpatient settings. Those with positive culture results were treated under appropriate antibiotic coverage. Seven patients were treated under general anesthesia and the rest under sedoanalgesia. Shielding of the lung fields or gonads was not used. For the upper pole stones, protection of the lungs was accomplished by elevating the upper half of the body with supportive pillows, thus moving the kidney away from the lung fields. Six RUs were catheterized via double-pigtail ureteral catheters or by percutaneous nephrostomy tube prior to treatment. The average stone load was 1.8+/-2.5 cm2.

RESULTS

Patients were treated with an average of 2.5 sessions. A total of 1000 to 2500 shockwaves were delivered between 14.5 and 17.8 kV. Routine spasmolytic treatment was not initiated. The stone-free rate was 64%, and clinically insignificant residual fragments (CIRF) were present in 29% of RUs; thus, the success rate was 93%. Fever that necessitated hospitalization occurred in one patient. No other complications were seen except skin bruising and early hematuria.

CONCLUSION

Shockwave lithotripsy is a safe and effective treatment modality for childhood stones of appropriate size and radiologic characteristics.

Percutaneous nephrolithotomy in infants and preschool age children: experience with a new technique

OBJECTIVES

To develop a less invasive method for performing percutaneous nephrolithotomy (PCNL) with the intent of decreasing the morbidity of the procedure in young children.

METHODS

A novel percutaneous renal access technique ("mini-perc") was developed using an 11F peel-away vascular access sheath. Tract dilation and insertion of the sheath into the collecting system was performed with a single pass over an access wire. PCNL was performed using pediatric instruments and electrohydraulic lithotripsy. Sheath design improvements were implemented that make it specific for pediatric PCNL.

RESULTS

Eleven procedures have been performed with the 11F sheath. Patient age ranged from 2 to 6 years (mean 3.4) and weight from 5 to 24 kg (mean 12.5). The average stone burden was 1.2 cm2. Mean procedure time, estimated blood loss, and length of hospitalization were 203 minutes, 25 mL, and 6 days, respectively. Six (85%) of 7 patients are currently stone free with an average follow-up of 12 weeks. No patient required transfusion, developed urosepsis, or had a procedure-related complication. One procedure was performed in an outpatient setting with no postoperative nephrostomy tube.

CONCLUSIONS

The 11F "mini-perc" technique was successful in rendering 85% of patients stone free with minimal morbidity. Its advantages over obtaining access with standard 24 to 34F access sheaths include a smaller skin incision, single-step dilation and sheath placement, good working access for pediatric instruments, variable length, and lower cost. In addition, the hypothesized decrease in renal and body wall trauma may result in less pain, reduced severity or risk of complications, and shorter hospital stays including the possibility of performing "tubeless" outpatient PCNLs. Further study is needed to confirm these possibilities.

Renal calculus disease

We have seen an explosion in technical innovations for the management of urolithiasis. Today, the endourologist possesses an assortment of minimally invasive tools to treat renal stones. Most patients receive fast, safe and effective treatment in the outpatient setting. Despite the many technical advances, however, anatomical malformations and complex stones still provide significant challenges in diagnosis, access to a targeted stone, fragmentation, and clearance of the resulting fragments. This review examines a variety of urinary stone presentations and treatment strategies for cost-effective management.

Report of the American Society of Nephrology meetings

PURPOSE

We summarize presentations on topics of interest to the pediatric urologist from the annual meeting of the American Society of Nephrology, November 1996.

MATERIALS AND METHODS

We reviewed all abstracts submitted for presentation and subsequently published in abstract form. Only those abstracts containing information pertinent to the field of pediatric urology were summarized for this report.

RESULTS

A total of 24 abstracts addressing a variety of topics were summarized. Obstructive uropathy was represented by the greatest number of papers and reflects the multiple investigative efforts currently evaluating the cellular aspects of this disorder. The genetic basis of hypercalciuria and the impact of water metabolism on nephroliathisis were also discussed.

CONCLUSIONS

Clinical and basic research activities that are of mutual interest to pediatric urologists and nephrologists are being conducted. The topic of obstructive uropathy has received the greatest attention during the last year. However, additional research, potentially collaborative in nature, on topics such as nephroliathisis and reflux nephropathy should be encouraged.