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Published on: February 9, 2021
Are small residual stone fragments really insignificant in children?
Nida Dincel1, Berkan Resorlu, Ali Unsal
1Department of Pediatric Nephrology, Ege University, Faculty of Medicine, Izmir, Turkey.
Insights
Pediatric kidney stones less than 4mm, termed clinically insignificant residual fragments (CIRFs), often become symptomatic or regrow. These fragments require careful monitoring as spontaneous passage is uncommon.
Area of Science:
- Pediatric Urology
- Nephrolithiasis Management
- Minimally Invasive Surgery
Background:
- Residual stone fragments after pediatric urolithiasis procedures are common.
- The clinical significance of small (less than 4mm) asymptomatic residual fragments, termed clinically insignificant residual fragments (CIRFs), remains debated.
- Current management strategies often involve observation, but the natural history of CIRFs in children is not well-defined.
Purpose of the Study:
- To evaluate the significance of asymptomatic residual stone fragments (<4mm) in children following shock wave lithotripsy (SWL), percutaneous nephrolithotomy (PNL), and retrograde intrarenal surgery (RIRS).
- To determine the rates of spontaneous passage, re-growth, and symptomatic events associated with these residual fragments.
- To assess the appropriateness of the term "clinically insignificant residual fragments" (CIRFs) in the pediatric population.
Main Methods:
- A prospective study followed 85 children with residual fragments (<4mm) for a median of 22 months (range 6-50 months).
- Outcomes assessed included spontaneous fragment passage, fragment re-growth, and stone-related events (e.g., emergency visits, hospitalizations, interventions).
- Statistical analysis was performed to evaluate factors influencing outcomes, including stone location and number.
Main Results:
- 25.8% of children spontaneously passed residual fragments, with higher rates for renal pelvis stones (57.1%) versus lower pole stones (16.1%).
- 40% of patients experienced symptomatic episodes (renal colic, UTI, hematuria), and 21.2% had fragment re-growth.
- 29.4% required secondary interventions, and 23.5% needed medical management for complications, suggesting CIRFs are not always insignificant.
Conclusions:
- The term "clinically insignificant residual fragments" (CIRFs) may not be appropriate for postoperative residual fragments in children.
- A significant proportion of children with CIRFs experience symptoms, fragment re-growth, or require further interventions.
- Close monitoring and potentially proactive management of residual fragments in pediatric stone disease are warranted.
Objectives:
To assess the significance of asymptomatic residual stone fragments of less than 4mm (clinically insignificant residual fragments [CIRFs]) after shock wave lithotripsy (SWL), percutaneous nephrolithotomy (PNL), and retrograde intrarenal surgery (RIRS) in children.
Patients And Methods:
Eighty-five children were followed up for 6 to 50months (median 22). Outcomes measured were fragment re-growth, stone events (emergency department visits, hospitalization, or additional interventions) and spontaneous fragment passage.
Results:
During follow-up, 22 children (25.8%) passed residual fragments spontaneously. Highest spontaneous passage rate was found for renal pelvis stones and the lowest for the lower pole stones (57.1% vs. 16.1%; p<0.001). When the number of the fragments increased, the chance of the spontaneous passage decreased (30% vs 20%; p<0.05). Symptomatic episodes including renal colic, hematuria, or urinary tract infection were documented in 34 (40%) patients, and re-growth of fragments was observed in 18 (21.2%). Stone size had no significant effect on spontaneous passage (p=0.079), stone growth (p=0.528), and symptomatic episodes (p=0.402). Twenty-five patients (29.4%) required secondary intervention for stone re-growth or stone related events and the remaining 20 patients (23.5%) needed medical treatment for bothersome symptoms or complications.
Conclusions:
Our results suggest that 40% of children with CIRFs will become symptomatic and 20% will develop stone re-growth over the following 6months. Only one fifth of the fragments will pass spontaneously without any complications. Therefore, the use of the term "CIRF" is not appropriate for postoperative residual fragments in children.
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