Outcome of conservative management of small renal stones in prepubertal children.

Abstract

INTRODUCTION: Renal stones are relatively uncommon in the pediatric population. This study aimed to evaluate the utility of conservative management of small renal stones in prepubertal children. PATIENTS AND METHODS: A retrospective chart review was conducted for children (&#x2264;12 years old) with small renal stones (3-10 mm) from 2016 to 2023 who underwent conservative management. Management included periodic renal ultrasonography, every 6 months, in addition to good hydration. Stones were confirmed by two consecutive ultrasounds. We recorded the patient's demographics and ultrasound findings (stone side, size, laterality, location, number, and associated hydronephrosis). Surgical intervention was indicated if recurrent loin pain, recurrent UTI, or worsening hydronephrosis (obstructing stone). Nephrolithiasis was considered resolved if stones were not visualized on 2 consecutive ultrasounds. Moreover, we evaluated conservative management outcomes for those presented during infancy (<12 months) versus later. RESULTS: We included 52 patients (65renal units) who presented at a median age of 46.1months (5.3-155.1). Seventy-five percent of patients had incidental renal stones. The median stone size was 4 mm (3-10). Forty-six percent of stones were in the lower calyx. The majority (70.8 %) had no hydronephrosis at presentation. During a median follow-up of 39months, 15patients with 17units (26.2 %) were documented stone-free. Ten patients (19.2 %) had symptomatic stone events, all measured &#x2265;4 mm. Of them, 6 patients (6 units) underwent surgical interventions, and 4 patients (4 units) experienced complications. A ROC curve analysis identified a stone size cutoff of 4 mm (sensitivity 100 % and 29 % specificity) that could be associated with symptomatic stone events. Using a multivariate Cox regression model, stone size was the only significantly associated factor with subsequent surgical intervention (p = 0.007). 19 % (10patients,12units) presented during infancy. Notably, the incidence of stone-free rate was significantly higher during infancy compared to older children (58.3 % vs 18.9 %,respectively). DISCUSSION: During a 39-month follow-up, 4 patients developed complications (2recurrent pain and 2 experienced UTI), supporting the safety of conservative management of small renal stones. This study is limited due to its retrospective design and the reliance on ultrasound as the main imaging method. To minimize that, all ultrasound images were carefully reviewed by two pediatric urologists. Moreover, renal stones were confirmed using strict criteria, which required detection in two consecutive ultrasounds. CONCLUSION: Although 26.2 % of units had spontaneously resolved nephrolithiasis, surgical intervention was only required in 11.5%of patients, all of whom had renal stones&#x2265;4 mm. Infants had higher spontaneous resolutions without complications, suggesting that conservative management may be especially effective in this subgroup.