Clinically Insignificant Residual Fragments: Is It an Appropriate Term in Children?

OBJECTIVE

To assess the outcome of clinically insignificant residual fragments (CIRFs) after shock wave lithotripsy (SWL) and percutaneous nephrolithotomy (PNL) in children.

METHODS

Sixty-one children with CIRFs diagnosed by noncontrast computed tomography (NCCT) 3 months after SWL and 1 month after PNL with documented follow-up ≥6 months were included in the study. Children were evaluated by urinalysis, urine culture, plain abdominal radiography, and urinary ultrasonography or noncontrast computed tomography. Outcomes measured were fragment regrowth, spontaneous fragment passage, and secondary interventions. A clinically significant outcome was defined as the need for secondary intervention for development of complications or regrowth of the residual fragment (RF).

RESULTS

The study included 42 boys and 19 girls with mean age of 6.2 years (range 1-14). After a median follow-up of 18 months, 16 children (26.2%) passed RF spontaneously. Regrowth of the RF was observed in 15 children (24.6%), and in 4 children (6.6%) the RF (of the same original size) slipped to the ureter and was treated by ureteroscopy. Therefore, a clinically significant outcome occurred in 31.2% of children with RF. Children with history of stone disease were more likely to develop clinical significance with time (HR, 4.38; 95% CI, 1.37-14; P = .013)

CONCLUSION

The term CIRF is not appropriate for all children with post-SWL and -PNL fragments, as one-third of patients have had fragments that became clinically significant. History of stone disease was the only predictor of clinical significance.