Extracorporeal shock wave lithotripsy for cystine urolithiasis in children: outcome and complications

Can cystinuria decrease the effectiveness of RIRS with high-power ho:yag laser in children? Outcomes from a tertiary endourology referral center

Cystinuria, which is the cause of cystine urolithiasis, accounts for 2-6% of all urinary stones in children, has a low prevalence with a high recurrence rate, making this metabolic disorder a therapeutic challenge in pediatric population. The aim of this work is evaluate the efficacy and safety of retrograde intra-renal surgery (RIRS) in pediatric patients with cystinuria and kidney stones smaller than 2 cm. Prospective study of 64 stones treated in 22 retrograde intra-renal surgeries (RIRS) in cystinuric pediatric patients with renal or proximal ureteral stones less than 2 cm. Average age of 9.5 years. The following data were analyzed: demographics, stone characteristics and surgical data with intra- and postoperative complications. Location of the stones was 68.7% in the calyces, 20.3% in the renal pelvis, and 9.3% in the ureteropelvic junction; 41% of cases had multiple locations. The average cystinuria level before the procedure was 825 mg/dL. The anatomy of 73% of the interventions increased the difficulty of flexible ureteroscopy and decreased stone free rates, because distorted renal anatomy was present: sclerosis of the pelvis or infundibulum, abnormal calyceal dilations, or excluded calyces. Intraoperative complications occurred in 18.2% of the procedures. Reno-vesical ultrasound was performed in all patients in the first postoperative month, with an SFR of 59%. Cystinuric patients are a challenge for pediatric urologists, decreasing the effectiveness of RIRS. However, it could be better treatment than SWL and with fewer complications than PCNL in the pediatric population with this disease.

Extracorporeal Shockwave Lithotripsy for Cystine Stones in Children: An Observational, Retrospective, Single-Center Analysis

Purpose: Cystinuria is a genetic disorder characterized by a defective reabsorption of cystine and dibasic amino acids leading to development of urinary tract calculi from childhood onward. Cystine lithiasis is known to be resistant to fragmentation. The aim was to evaluate our long-term experience with extracorporeal shockwave lithotripsy (ESWL) used as first-line urological treatment to treat cystine stones in children. Methods: We retrospectively reviewed the charts of all children who underwent ESWL for cystine stone. We assessed the 3-month stone-free rate, according to age, younger (group 1) or older (group 2) than 2 years old. Results: Between 2003 and 2016, 15 patients with a median (IQR) age at first treatment of 48 (15-108) months underwent ESWL in monotherapy. Median age was, respectively, 15 and 108 months in each group. The median (IQR) stone burden was 2,620 (1,202-8,265) mm³ in group I and 4,588 (2,039-5,427) mm³ in group II (p = 0.96). Eleven patients had bilateral calculi. ESWL was repeated on average 2.4 times, with a maximum of 4 for patients of group I, and 4.8 times, with a maximum of 9 for group II (p > 0.05). ESWL in monotherapy was significantly more efficient to reach stone-free status for children under 2 years of age: 83% vs. 6.2% (p = 0.040). The median (IQR) follow-up of the study was 69 (42-111) months. Conclusion: ESWL appears as a valid urological option for the treatment of cystine stones, in young children. Even if cystine stones are known to be resistant to fragmentation, we report 83% of stone-free status at 3 months with ESWL used in monotherapy in children under 2 years old with cystinuria. In older children, the success rate is too low to recommend ESWL as a first line approach.

Comparison of extracorporeal shockwave lithotripsy and retrograde intrarenal surgery in the treatment of renal pelvic and proximal ureteral stones ≤2 cm in children

Introduction:

We aimed to compare extracorporeal shockwave lithotripsy (ESWL) and retrograde intrarenal surgery (RIRS) in pediatric patients with ≤2 cm renal pelvis and proximal ureteral stones.

Methods:

Medical records of 165 pediatric patients who underwent shockwave lithotripsy (SWL) or RIRS for upper urinary system stones up to 2 cm between January 2014 and December 2018 were retrospectively reviewed. After exclusions, the remaining 130 patients included 73 in the SWL group and 57 in the RIRS group. The groups were compared for demographic features, stone characteristics, operative data, success, and complications.

Results:

The mean stone volume was 308 ± 85 (54–800) and 336 ± 96 (60–720) mm³ in SWL and RIRS groups, respectively (P = 0.46). There were no significant differences in success rates (60% vs. 70%, SWL and RIRS), auxiliary treatment rates (16.4% vs. 14%), and complication rates (26% vs. 24.5%). The number of active procedural sessions and number of anesthesia sessions was higher in the RIRS group (P < 0.001 and P < 0.001, respectively), while the procedural time and anesthesia time were higher in the SWL group (P < 0.001 and P < 0.001, respectively). Stone size was found to be an independent success predictive factor for both the treatment modalities.

Conclusions:

Both SWL and RIRS have similar success, complication, and auxiliary treatment rates. RIRS was superior in terms of total procedure and anesthesia durations, while SWL was superior in terms of numbers of anesthesia sessions and active procedure sessions. As both have similar success rates, the more minimally invasive SWL should be chosen for pediatric upper urinary system stones of less than 2 cm size.

Cystinuria: genetic aspects, mouse models, and a new approach to therapy

Cystinuria, a genetic disorder of cystine transport, is characterized by excessive excretion of cystine in the urine and recurrent cystine stones in the kidneys and, to a lesser extent, in the bladder. Males generally are more severely affected than females. The disorder may lead to chronic kidney disease in many patients. The cystine transporter (b^0,+) is a heterodimer consisting of the rBAT (encoded by SLC3A1) and b^0,+AT (encoded by SLC7A9) subunits joined by a disulfide bridge. The molecular basis of cystinuria is known in great detail, and this information is now being used to define genotype-phenotype correlations. Current treatments for cystinuria include increased fluid intake to increase cystine solubility and the administration of thiol drugs for more severe cases. These drugs, however, have poor patient compliance due to adverse effects. Thus, there is a need to reduce or eliminate the risks associated with therapy for cystinuria. Four mouse models for cystinuria have been described and these models provide a resource for evaluating the safety and efficacy of new therapies for cystinuria. We are evaluating a new approach for the treatment of cystine stones based on the inhibition of cystine crystal growth by cystine analogs. Our ongoing studies indicate that cystine diamides are effective in preventing cystine stone formation in the Slc3a1 knockout mouse model for cystinuria. In addition to crystal growth, crystal aggregation is required for stone formation. Male and female mice with cystinuria have comparable levels of crystalluria, but very few female mice form stones. The identification of factors that inhibit cystine crystal aggregation in female mice may provide insight into the gender difference in disease severity in patients with cystinuria.

Retrograde intrarenal surgery in the management of pediatric cystine stones

OBJECTIVE

To investigate the efficacy and safety of retrograde intrarenal surgery (RIRS) in the treatment of pediatric cystine stones.

STUDY DESIGN

Data of the pediatric patients who underwent RIRS for kidney stones were retrospectively evaluated. A total of 14 children with cystine stones managed with RIRS were identified. In addition to the patient demographics and stone characteristics, all retrospectively obtained operative data were evaluated and discussed in detail, with an emphasis on the success and complication rates.

RESULTS

Mean age of the 14 cases was 10.9 ± 2.2 years (range: 7-15). Mean stone size was 13.6 ± 2.4 mm (range: 10-18) (Summary table). Of these stones, four were located in the renal pelvis, three were in the lower, three were in the middle and the remaining four were located in upper calyx. Ureteral access sheath was used in 12 (85.7%) patients. The double-J ureteral stent was placed pre-operatively in one case and was inserted postoperatively in 12 cases. Mean operation time was 38.2 ± 7.2 min (range: 30-50). Complications were observed in two cases: mild ureteral laceration in the first and fever on the second postoperative day in the second patient. All of the patients were stone free on sonographic evaluation at the 4-week follow-up evaluation. Although potassium citrate treatment was initiated in 11 patients, tiopronin treatment was initiated in four patients for recurrence prophylaxis during long-term follow-up. During a mean follow-up period of 25.7 ± 5.2 months, stone recurrence was noted in one patient.

DISCUSSION

Treatment of patients with cystine stones is challenging, due to high risk of rapid recurrence in the presence of residual fragments. Besides allowing complete stone clearance in all cases in the current series, RIRS is a highly reproducible method that can be safely performed, even in recurrences. The major limitations of the current study were low number of patients and short follow-up period.

CONCLUSION

The results clearly indicated that RIRS is a safe treatment modality in the management of pediatric cystine stones.

[Cystinuria in children: A report of 4 cases]

Cystinuria is an inherited autosomal-recessive disorder of renal reabsorption of the dibasic amino acids. It is the cause of about 6% of all kidney stones observed in children. Cystine is relatively insoluble at the physiological pH of urine. Cystine stones are characteristic and frequent recurrences are observed. We report on 4 cases and describe the initial presentation (obstructive renal failure, urinary sepsis, familial screening) and the medical and surgical management. Medical management is mainly based on hyperhydration and urine alkalinization. Long-term therapy with sulfhydryl agents to prevent formation of renal stones seems to be effective but adverse side effects are frequent, requiring the withdrawal of treatment. Urological management has evolved from surgical stone removal to minimally invasive procedures (extracorporeal shock wave lithotripsy, ureteroscopy).

Nephrotic syndrome occurring during tiopronin treatment for cystinuria

Cystinuria is an autosomal recessive disorder characterized with abnormal tubular reabsorption of cystine and dibasic amino acids leading to cystine urolithiasis. The classical form is caused by mutations in the SLC3A1 gene (OMIM 220100). The cornerstone of the treatment is high hydration and alkalization of the urine to achieve urine pH between 7.0 and 7.5, at which point, cystine solubility in the urine is optimal. These measures very often fail, and thus addition of sulfhydryl agents like penicillamine and tiopronin (mercaptopropionyl glycine) is recommended. Herein, we report a 3-year-old boy with cystinuria resulting in recurrent nephrolithiasis requiring surgery and extracorporeal shock wave lithotripsy. Nine months after introduction of tiopronin, the boy manifested generalized edema, oliguria, and biochemical indices of nephrotic syndrome. Tiopronin was withdrawn, and the boy was given only supportive treatment. Within 10 days, he entered into clinical and biochemical remission. Pediatricians should be aware of this adverse effect of tiopronin, and therefore, testing of the urine with strips or sulfosalicylic acid at least once weekly at home may be very helpful for early detection of proteinuria.

Evaluation of renal function in children undergoing extracorporeal shock wave lithotripsy

PURPOSE

The effect of extracorporeal shock wave lithotripsy on the growing kidneys of young children has always been a concern. We determined whether shock wave lithotripsy causes renal parenchymal scarring or affects glomerular filtration rate in children.

MATERIALS AND METHODS

This prospective study included 100 children with renal stones who presented to the shock wave lithotripsy unit at our institution between March 2005 and March 2008. A total of 28 children had multiple stones in the same kidney. All children with bilateral renal stones had 1 kidney cleared of stones by percutaneous nephrolithotomy before undergoing shock wave lithotripsy. A total of 138 stones were subjected to shock wave lithotripsy. All children underwent radionuclide scan of the renal parenchyma using dimercapto-succinic acid, and glomerular filtration rate was estimated using diethylenetriamine pentaacetic acid before extracorporeal shock wave lithotripsy and 6 months afterward. Children with renal scarring due to previous surgery or vesicoureteral reflux were excluded from the study. The number of shock wave lithotripsy sessions to achieve stone-free status and the dose of shock waves used were recorded for each patient.

RESULTS

No patient demonstrated renal parenchymal scarring on dimercapto-succinic acid scan or any statistically significant change in glomerular filtration rate on diethylenetriamine pentaacetic acid scan up to 6 months after shock wave lithotripsy.

CONCLUSIONS

Shock wave lithotripsy is a safe modality for treating renal calculous disease in children up to 16 years old, with no impact on long-term kidney function.

Contemporary surgical management of pediatric urolithiasis

With miniaturization of instruments and refinement of surgical technique, the management of pediatric stone disease has undergone a dramatic evolution. While shock wave lithotripsy (SWL) is still commonly used to treat upper tract calculi, the use of ureteroscopy (URS) has dramatically increased and is now the procedure of choice for upper tract stone burdens less than 1.5cm at centers with significant experience. Percutaneous nephrolithotomy (PCNL) has replaced open surgical techniques for the treatment of large stone burdens greater than 2cm, with efficacy and complication rates similar to the adult population. Large institutional series demonstrate comparable stone-free and complication rates with SWL, URS, and PCNL, but concerns remain with these techniques regarding renal development and damage to the pediatric urinary tract. Randomized controlled trials comparing the efficacy of SWL and URS for upper tract stone burdens are needed to reach consensus regarding the most effective primary treatment modality in children.

Management of Cystinuria

Cystinuria is a monogenic disorder in which there is a transepithelial transport defect of di-basic amino acids, including cystine, ornithine, lysine, and arginine (COLA). This results in diminished reabsorption of these amino acids in both the intestine and renal proximal tubule. This article describes the disorder, reviews the mechanisms of normal COLA renal transport, and summarizes issues related to the disorder, such as the role of mutations, associated diseases, clinical manifestations, therapies, the renal impact, and handling of pediatric patients.

Early results of robot assisted laparoscopic lithotomy in adolescents

PURPOSE

The treatment of large stone burdens in children is difficult and often requires multiple procedures using a combination of therapies. Recently, laparoscopy has been shown to be effective in the management of larger stone burdens. We report our experience with robot assisted laparoscopic lithotomy in adolescents, and describe our technique.

MATERIALS AND METHODS

We retrospectively reviewed our experience with robot assisted laparoscopic pyelolithotomy in 5 patients operated on between 2002 and 2005. Mean patient age at surgery was 16.6 years, and mean followup was 15.4 months.

RESULTS

Cystine was the etiology in 4 patients with staghorn stones. The remaining patient had calcium oxalate stones and concurrent ureteropelvic junction obstruction. After pyelotomy stones were removed by a robotic grasper or by a flexible cystoscope introduced through a robotic port. One of the patients had an indwelling ureteral stent placed preoperatively, while 4 had stents placed robotically intraoperatively. Mean operative time was 315.4 minutes (range 165.0 to 462.0), and mean estimated blood loss was 19.0 ml (0.0 to 50.0). Mean hospital stay was 3.8 days (range 2.3 to 5.7), and mean narcotic usage was 2.1 mg/kg morphine (1.5 to 3.5). One patient with a cystine staghorn calculus required conversion to an open procedure because of inability to remove the stone. Of the 4 cases completed robotically 3 were rendered stone-free and 1 had a residual 6 mm lower pole stone.

CONCLUSIONS

The early results of robot assisted laparoscopic lithotomy reveal that the procedure is safe and efficacious. Further prospective studies comparing other minimally invasive procedures used for similar stone burdens are needed to determine the benefits of this procedure and its role in stone management.

Extracorporeal shock wave lithotripsy in the management of pediatric urolithiasis

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

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

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