title: Retrograde intrarenal surgery in the management of pediatric cystine stones.
abstract: OBJECTIVE
  To investigate the efficacy and safety of retrograde intrarenal surgery (RIRS) in the treatment of pediatric cystine stones.
  
  
  METHODS
  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.
  
  
  CONCLUSIONS
  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.
  
  
  CONCLUSIONS
  The results clearly indicated that RIRS is a safe treatment modality in the management of pediatric cystine stones.
authors.affiliation: Department of Urology, Bagcilar Research and Training Hospital, Istanbul, Turkey. Electronic address: emrah.yuruk@yahoo.com.
authors.forename: E
authors.initials: E
authors.lastname: Yuruk
authors.affiliation: Department of Urology, Bagcilar Research and Training Hospital, Istanbul, Turkey.
authors.forename: M
authors.initials: M
authors.lastname: Tuken
authors.affiliation: Department of Urology, Bagcilar Research and Training Hospital, Istanbul, Turkey.
authors.forename: S
authors.initials: S
authors.lastname: Gonultas
authors.affiliation: Department of Urology, Bagcilar Research and Training Hospital, Istanbul, Turkey.
authors.forename: A
authors.initials: A
authors.lastname: Colakerol
authors.affiliation: Department of Urology, Bagcilar Research and Training Hospital, Istanbul, Turkey.
authors.forename: O O
authors.initials: OO
authors.lastname: Cakir
authors.affiliation: Department of Urology, Bagcilar Research and Training Hospital, Istanbul, Turkey.
authors.forename: M
authors.initials: M
authors.lastname: Binbay
authors.affiliation: Department of Urology, Dr. Lutfi Kirdar Kartal Training and Research Hospital, Istanbul, Turkey.
authors.forename: K
authors.initials: K
authors.lastname: Sarica
authors.affiliation: Department of Urology, Bagcilar Research and Training Hospital, Istanbul, Turkey.
authors.forename: A Y
authors.initials: AY
authors.lastname: Muslumanoglu
mesh_terms: D000293:Adolescent; D000768:Anesthesia, General / Q000379:methods; D002648:Child; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007669:Kidney Calculi / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D019060:Minimally Invasive Surgical Procedures / Q000379:methods; D009403:Nephrostomy, Percutaneous / Q000295:instrumentation / Q000379:methods*; D061214:Patient Safety; D019357:Potassium Citrate / Q000737:chemistry; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D015607:Stents; D016896:Treatment Outcome; D018608:Ultrasonography, Doppler / Q000379:methods; D018666:Ureteroscopy / Q000379:methods
chemical_list: D019357:Potassium Citrate
keywords: Cystine stone; Flexible ureteroscopy; Pediatric; Retrograde intrarenal surgery