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

Nicolas Vinit,Pauline Lopez,Thomas Blanc,Antoine Khoury,Olivia Boyer,Laurence Heidet,Henri B Lottmann,Olivier Traxer,Nathalie Botto

doi:10.3389/fped.2021.763317

Abstract

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.

Highlights

Cystinuria is a rare autosomal recessive genetic disorder characterized by defective reabsorption of cystine and other dibasic amino acids in the renal proximal tubule and intestinal epithelial cells [1]
With the approval from the Necker-Enfants Malades Hospital’s institutional review board, we retrospectively reviewed the data of all children treated in our center for cystine stones with at least one urological procedure for upper urinary tract stones
Between 2003 and 2016, 210 children were treated in our department for upper urinary tract stones

Summary

Introduction

Cystinuria is a rare autosomal recessive genetic disorder characterized by defective reabsorption of cystine and other dibasic amino acids (ornithine, lysine, and arginine) in the renal proximal tubule and intestinal epithelial cells [1]. Dysfunction of this transport mechanism is due to mutations in solute carrier genes SLC3A1 or in SLC7A9 [2]. Cystinuria is responsible for 5 to 10% of pediatric stones [3] and more than half of patients will develop stones throughout their lifetime, with a higher risk of recurrence, bilaterality [4], and loss of renal function [5,6,7] than children with non-cystine stones. The goal is to reach a stone-free status to avoid recurrence

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Discussion

Conclusion