Vinit N. et al., 2021: Extracorporeal Shockwave Lithotripsy for Cystine Stones in Children: An Observational, Retrospective, Single-Center Analysis

Thursday, 14 April 2022

1921 Hits

Vinit N, Khoury A, Lopez P, Heidet L, Botto N, Traxer O, Boyer O, Blanc T, Lottmann HB.
Department of Pediatric Surgery and Urology, Necker-Enfants Malades Hospital, APHP, Paris, France.
Department of Pediatric Nephrology, Reference Center for Inherited Renal Disease (MARHEA), Necker-Enfants Malades Hospital, APHP, Paris, France.
INSERM UMR 1163, Laboratory of Inherited Kidney Diseases, Imagine Institute, Université de Paris, Paris, France.
Department of Urology, Tenon Hospital, APHP, Paris, France.
Groupe de Recherche Clinique sur la Lithiase Urinaire (GRC no 20), Tenon Hospital, Sorbonne Université, Paris, France.
Sorbonne Université, Paris, France.
Université de Paris, Paris, France.
INSERM U1151-CNRS UMR 8253, Université de Paris, Paris, France.

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
Front Pediatr. 2021 Nov 16;9:763317. doi: 10.3389/fped.2021.763317. eCollection 2021. PMID: 34869121. FREE ARTICLE

Comments 1

Hans-Göran Tiselius on Thursday, 14 April 2022 10:30

This is an interesting report on the usefulness of SWL for treating children with cystine stones.
The authors found that that for children below the age of 2, a stone-free rate of 83% was achieved. This is a result contrary to the general opinion and of great value given the “SWL-resistance” of cystine stones.
There are some factors that probably explain why stone-free rates at the same level were not obtained for children >2 years. The passage of fragments is much better in the youngest children because of the properties of the young ureter. Another explanation suggested by the authors is a better transmission of shockwaves. Although this is a possible explanation my personal view is that the aging stones react to shockwaves different from that in young and newly formed stones. The disintegration properties might change for stones that have been in the collecting system for a longer period. Personally, I was surprised how easily cystine stones in the very young child disintegrates.
The great advantage with SWL for children with cystine stones is that the stone removal can be completed non-invasively albeit repeated sessions might be necessary. This is particularly important for a group of patients in whom many surgical procedures might be necessary in the future. Importantly, the alternative treatment modality RIRS in the youngest patients may be associated with high rates of failure and complications [1].
Reference
1.Ishii H, Griffin S, Somani BK. Ureteroscopy for stone disease in the paediatric population: a systematic review. BJU Int 2015; 115:867-873
Hans-Göran Tiselius

This is an interesting report on the usefulness of SWL for treating children with cystine stones.
The authors found that that for children below the age of 2, a stone-free rate of 83% was achieved. This is a result contrary to the general opinion and of great value given the “SWL-resistance” of cystine stones.
There are some factors that probably explain why stone-free rates at the same level were not obtained for children >2 years. The passage of fragments is much better in the youngest children because of the properties of the young ureter. Another explanation suggested by the authors is a better transmission of shockwaves. Although this is a possible explanation my personal view is that the aging stones react to shockwaves different from that in young and newly formed stones. The disintegration properties might change for stones that have been in the collecting system for a longer period. Personally, I was surprised how easily cystine stones in the very young child disintegrates. 
The great advantage with SWL for children with cystine stones is that the stone removal can be completed non-invasively albeit repeated sessions might be necessary. This is particularly important for a group of patients in whom many surgical procedures might be necessary in the future. Importantly, the alternative treatment modality RIRS in the youngest patients may be associated with high rates of failure and complications [1].
Reference
1.Ishii H, Griffin S, Somani BK. Ureteroscopy for stone disease in the paediatric population: a systematic review. BJU Int 2015; 115:867-873
Hans-Göran Tiselius

Cancel Update Comment