What is the fate of insignificant residual fragment following percutaneous nephrolithotomy in pediatric patients with anomalous kidney? A comparison with normal kidney.

Pediatric population has increasing incidence of renal calculus and it is estimated to be around 50/10,000 population. The treatment of choice for large and complex stone in anomalous kidney is percutaneous nephrolithotomy (PCNL). The fate of insignificant residual fragment after PCNL in pediatric patients is not well documented. Here, we are reporting our long-term experience and follow-up of insignificant residual fragment in pediatric patients with anomalous kidney in comparison to normal kidney. Intuitional ethical approval was taken. A retrospective analysis of PCNL in pediatric (<18 years) anomalous kidney was performed from 2001 to 2013. The data of 52 pediatric patients with anomalous kidney (group B) have been compared to 251 normal kidneys (group A). The mean age of the patients was 7.83 + 3.45 (range 3-18) in group A and 8.21 ± 3.25 (range 5-18) in group B. The mean size of the insignificant residual fragment was 2.2 + 0.5 mm (1-4) in group A and 2.1 + 0.6 mm (range 1-4) in group B. Most of these residual fragments were single in number (72.55 vs. 67.30%, respectively). 54.98% children in group A and 67.30% in group B were symptomatic in the follow-up. Stone size was increased, stable and spontaneously passed in 49.8 vs. 71.15, 22.7 vs. 19.23 and 27.49 vs. 9.61% (p < 0.03), respectively, over mean follow-up of 50.34 months. Insignificant residual fragments in children are notorious for regrowth (49.8% in normal and 71.15% in anomalous kidney) in future. Most of the children will require symptomatic treatment (55.37 vs. 82.69%) or reintervention (39 vs. 46%) for insignificant residual fragment.