Retrograde intrarenal surgery in the management of pediatric cystine stones

Summary 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. Summary table . Stone characteristics and operative findings. Number of patients 14 Mean stone size (mm) 13.6 ± 2.4 (range: 10–18) Stone location Renal pelvis 4 Upper calyx 4 Middle calyx 3 Lower calyx 3 Mean operation time (minutes) 38.2 ± 7.2 (range: 30–50) Postoperative fever 1 (7.1%) Stone-free rate 100%